[PATCH 00/10 v2] xfs: LARP - clean up xfs_attr_set_iter state machine

[PATCH 00/10 v2] xfs: LARP - clean up xfs_attr_set_iter state machine

[Dave Chinner]

HI folks,

Version 2 is here and working better. The first 11 patches are
largely the same as the first version, just we a couple of bugs
fixes which caused a couple patches to be reworked to fix conflicts.
These patches set up the xfs_attr_set_iter() state machine to be
more readable and maintainable. It largely jsut worked with LARP=0,
but failed on the first recovery when LARP was enabled.

I realised that recovery wasn't setting the initial state properly,
and then started digging into the recovery code. At this point, I
realised the recovery code didn't work correctly in all cases and
could often leave unremovable incomplete attrs sitting around. The
issues are larger documented ini patch 16 so I won't go over them
here, just read that patch.

However, to get, the whole replace operation for LARP=1 needed to
change. Luckily, that turned out to be pretty simple because it was
largely already broken down into component operations in the state
machine. hence I just needed to add new "remove" initial states to
the set_iter state machine, and that allowed the new algorithm to
function.

Then I realised that I'd just implemented the remove_iter algorithm
in the set_iter state machine, so I removed the remove_iter code and
it's states altogether and just pointed remove ops at the set-iter
remove initial states. The code now uses the XFS_DA_OP_RENAME flag
to determine if it should follow up an add or remove with a remove
or add, and it all largely jsut works. All runtime algorithms run
throught he same state machine just with different initial states
and state progressions.

And with patch 16, attr item log recovery uses that same state
machine, too. It has a few quirks that need to be handled, so I
added the XFS_DA_OP_RECOVERY flag to allow the right thing to be
done with the INCOMPLETE flag deep in the guts of the attr lookup
code. And so recovery with LARP=1 now seems to mostly work.

The current state is that larp=0 seems to pass attr group and
recoverloop group testing just fine. My current build is about 10
loops in without a failure. With larp=1, attr group passes jsut
fine, but I'm getting random recovery failures with recoveryloop
testing that aren't immediately obvious as being attribute intent
recvoery failures.  (e.g. things like unlinked inode recovery
finding inodes on the unlinked list that have nlink != 0). Hence
while it mostly works, I'm sure there are still some bugs lurking
there.

There's also a fair bit of cleanup needed of the last couple of
patches. There's some quirks in the state change code when
completing an op and determining whether we need to run the second
half of a replace op that need cleaning up, and the last patch needs
further splitting up and it changes stuff all over the place.

However, if you want to get an idea of what the code looks like,
see if it runs and breaks on your machines and maybe find some bugs
in it, help is welcome!

Cheers,

Dave.

[PATCH 01/16] xfs: avoid empty xattr transaction when attrs are inline

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

generic/642 triggered a reproducable assert failure in
xlog_cil_commit() that resulted from a xfs_attr_set() committing
an empty but dirty transaction. When the CIL is empty and this
occurs, xlog_cil_commit() tries a background push and this triggers
a "pushing an empty CIL" assert.

XFS: Assertion failed: !list_empty(&cil->xc_cil), file: fs/xfs/xfs_log_cil.c, line: 1274
Call Trace:
 <TASK>
 xlog_cil_commit+0xa5a/0xad0
 __xfs_trans_commit+0xb8/0x330
 xfs_trans_commit+0x10/0x20
 xfs_attr_set+0x3e2/0x4c0
 xfs_xattr_set+0x8d/0xe0
 __vfs_setxattr+0x6b/0x90
 __vfs_setxattr_noperm+0x76/0x220
 __vfs_setxattr_locked+0xdf/0x100
 vfs_setxattr+0x94/0x170
 setxattr+0x110/0x200
 path_setxattr+0xbf/0xe0
 __x64_sys_setxattr+0x2b/0x30
 do_syscall_64+0x35/0x80

The problem is related to the breakdown of attribute addition in
xfs_attr_set_iter() and how it is called from deferred operations.
When we have a pure leaf xattr insert, we add the xattr to the leaf
and set the next state to XFS_DAS_FOUND_LBLK and return -EAGAIN.
This requeues the xattr defered work, rolls the transaction and
runs xfs_attr_set_iter() again. This then checks the xattr for
being remote (it's not) and whether a replace op is being done (this
is a create op) and if neither are true it returns without having
done anything.

xfs_xattri_finish_update() then unconditionally sets the transaction
dirty, and the deferops finishes and returns to __xfs_trans_commit()
which sees the transaction dirty and tries to commit it by calling
xlog_cil_commit(). The transaction is empty, and then the assert
fires if this happens when the CIL is empty.

This patch addresses the structure of xfs_attr_set_iter() that
requires re-entry on leaf add even when nothing will be done. This
gets rid of the trailing empty transaction and so doesn't trigger
the XFS_TRANS_DIRTY assignment in xfs_xattri_finish_update()
incorrectly. Addressing that is for a different patch.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 39 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 48b7e7efbb30..b3d918195160 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -315,6 +315,7 @@ xfs_attr_leaf_addname(
 {
 	struct xfs_da_args	*args = attr->xattri_da_args;
 	struct xfs_inode	*dp = args->dp;
+	enum xfs_delattr_state	next_state = XFS_DAS_UNINIT;
 	int			error;
 
 	if (xfs_attr_is_leaf(dp)) {
@@ -335,37 +336,35 @@ xfs_attr_leaf_addname(
 			 * when we come back, we'll be a node, so we'll fall
 			 * down into the node handling code below
 			 */
-			trace_xfs_attr_set_iter_return(
-				attr->xattri_dela_state, args->dp);
-			return -EAGAIN;
+			error = -EAGAIN;
+			goto out;
 		}
-
-		if (error)
-			return error;
-
-		attr->xattri_dela_state = XFS_DAS_FOUND_LBLK;
+		next_state = XFS_DAS_FOUND_LBLK;
 	} else {
 		error = xfs_attr_node_addname_find_attr(attr);
 		if (error)
 			return error;
 
+		next_state = XFS_DAS_FOUND_NBLK;
 		error = xfs_attr_node_addname(attr);
-		if (error)
-			return error;
-
-		/*
-		 * If addname was successful, and we dont need to alloc or
-		 * remove anymore blks, we're done.
-		 */
-		if (!args->rmtblkno &&
-		    !(args->op_flags & XFS_DA_OP_RENAME))
-			return 0;
+	}
+	if (error)
+		return error;
 
-		attr->xattri_dela_state = XFS_DAS_FOUND_NBLK;
+	/*
+	 * We need to commit and roll if we need to allocate remote xattr blocks
+	 * or perform more xattr manipulations. Otherwise there is nothing more
+	 * to do and we can return success.
+	 */
+	if (args->rmtblkno ||
+	    (args->op_flags & XFS_DA_OP_RENAME)) {
+		attr->xattri_dela_state = next_state;
+		error = -EAGAIN;
 	}
 
+out:
 	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state, args->dp);
-	return -EAGAIN;
+	return error;
 }
 
 /*
-- 
2.35.1

Re: [PATCH 01/16] xfs: avoid empty xattr transaction when attrs are inline

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> generic/642 triggered a reproducable assert failure in
> xlog_cil_commit() that resulted from a xfs_attr_set() committing
> an empty but dirty transaction. When the CIL is empty and this
> occurs, xlog_cil_commit() tries a background push and this triggers
> a "pushing an empty CIL" assert.
> 
> XFS: Assertion failed: !list_empty(&cil->xc_cil), file:
> fs/xfs/xfs_log_cil.c, line: 1274
> Call Trace:
>  <TASK>
>  xlog_cil_commit+0xa5a/0xad0
>  __xfs_trans_commit+0xb8/0x330
>  xfs_trans_commit+0x10/0x20
>  xfs_attr_set+0x3e2/0x4c0
>  xfs_xattr_set+0x8d/0xe0
>  __vfs_setxattr+0x6b/0x90
>  __vfs_setxattr_noperm+0x76/0x220
>  __vfs_setxattr_locked+0xdf/0x100
>  vfs_setxattr+0x94/0x170
>  setxattr+0x110/0x200
>  path_setxattr+0xbf/0xe0
>  __x64_sys_setxattr+0x2b/0x30
>  do_syscall_64+0x35/0x80
> 
> The problem is related to the breakdown of attribute addition in
> xfs_attr_set_iter() and how it is called from deferred operations.
> When we have a pure leaf xattr insert, we add the xattr to the leaf
> and set the next state to XFS_DAS_FOUND_LBLK and return -EAGAIN.
> This requeues the xattr defered work, rolls the transaction and
> runs xfs_attr_set_iter() again. This then checks the xattr for
> being remote (it's not) and whether a replace op is being done (this
> is a create op) and if neither are true it returns without having
> done anything.
> 
> xfs_xattri_finish_update() then unconditionally sets the transaction
> dirty, and the deferops finishes and returns to __xfs_trans_commit()
> which sees the transaction dirty and tries to commit it by calling
> xlog_cil_commit(). The transaction is empty, and then the assert
> fires if this happens when the CIL is empty.
> 
> This patch addresses the structure of xfs_attr_set_iter() that
> requires re-entry on leaf add even when nothing will be done. This
> gets rid of the trailing empty transaction and so doesn't trigger
> the XFS_TRANS_DIRTY assignment in xfs_xattri_finish_update()
> incorrectly. Addressing that is for a different patch.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Ok makes sense, thx for catching this!
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 39 +++++++++++++++++++-------------------
> -
>  1 file changed, 19 insertions(+), 20 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 48b7e7efbb30..b3d918195160 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -315,6 +315,7 @@ xfs_attr_leaf_addname(
>  {
>  	struct xfs_da_args	*args = attr->xattri_da_args;
>  	struct xfs_inode	*dp = args->dp;
> +	enum xfs_delattr_state	next_state = XFS_DAS_UNINIT;
>  	int			error;
>  
>  	if (xfs_attr_is_leaf(dp)) {
> @@ -335,37 +336,35 @@ xfs_attr_leaf_addname(
>  			 * when we come back, we'll be a node, so we'll
> fall
>  			 * down into the node handling code below
>  			 */
> -			trace_xfs_attr_set_iter_return(
> -				attr->xattri_dela_state, args->dp);
> -			return -EAGAIN;
> +			error = -EAGAIN;
> +			goto out;
>  		}
> -
> -		if (error)
> -			return error;
> -
> -		attr->xattri_dela_state = XFS_DAS_FOUND_LBLK;
> +		next_state = XFS_DAS_FOUND_LBLK;
>  	} else {
>  		error = xfs_attr_node_addname_find_attr(attr);
>  		if (error)
>  			return error;
>  
> +		next_state = XFS_DAS_FOUND_NBLK;
>  		error = xfs_attr_node_addname(attr);
> -		if (error)
> -			return error;
> -
> -		/*
> -		 * If addname was successful, and we dont need to alloc
> or
> -		 * remove anymore blks, we're done.
> -		 */
> -		if (!args->rmtblkno &&
> -		    !(args->op_flags & XFS_DA_OP_RENAME))
> -			return 0;
> +	}
> +	if (error)
> +		return error;
>  
> -		attr->xattri_dela_state = XFS_DAS_FOUND_NBLK;
> +	/*
> +	 * We need to commit and roll if we need to allocate remote
> xattr blocks
> +	 * or perform more xattr manipulations. Otherwise there is
> nothing more
> +	 * to do and we can return success.
> +	 */
> +	if (args->rmtblkno ||
> +	    (args->op_flags & XFS_DA_OP_RENAME)) {
> +		attr->xattri_dela_state = next_state;
> +		error = -EAGAIN;
>  	}
>  
> +out:
>  	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state,
> args->dp);
> -	return -EAGAIN;
> +	return error;
>  }
>  
>  /*

[PATCH 02/16] xfs: initialise attrd item to zero

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

On the first allocation of a attrd item, xfs_trans_add_item() fires
an assert like so:

 XFS (pmem0): EXPERIMENTAL logged extended attributes feature added. Use at your own risk!
 XFS: Assertion failed: !test_bit(XFS_LI_DIRTY, &lip->li_flags), file: fs/xfs/xfs_trans.c, line: 683
 ------------[ cut here ]------------
 kernel BUG at fs/xfs/xfs_message.c:102!
 Call Trace:
  <TASK>
  xfs_trans_add_item+0x17e/0x190
  xfs_trans_get_attrd+0x67/0x90
  xfs_attr_create_done+0x13/0x20
  xfs_defer_finish_noroll+0x100/0x690
  __xfs_trans_commit+0x144/0x330
  xfs_trans_commit+0x10/0x20
  xfs_attr_set+0x3e2/0x4c0
  xfs_initxattrs+0xaa/0xe0
  security_inode_init_security+0xb0/0x130
  xfs_init_security+0x18/0x20
  xfs_generic_create+0x13a/0x340
  xfs_vn_create+0x17/0x20
  path_openat+0xff3/0x12f0
  do_filp_open+0xb2/0x150

The attrd log item is allocated via kmem_cache_alloc, and
xfs_log_item_init() does not zero the entire log item structure - it
assumes that the structure is already all zeros as it only
initialises non-zero fields. Fix the attr items to be allocated
via the *zalloc methods.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_attr_item.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
index 0e2ef0dedb28..b6561861ef01 100644
--- a/fs/xfs/xfs_attr_item.c
+++ b/fs/xfs/xfs_attr_item.c
@@ -725,7 +725,7 @@ xfs_trans_get_attrd(struct xfs_trans		*tp,
 
 	ASSERT(tp != NULL);
 
-	attrdp = kmem_cache_alloc(xfs_attrd_cache, GFP_NOFS | __GFP_NOFAIL);
+	attrdp = kmem_cache_zalloc(xfs_attrd_cache, GFP_NOFS | __GFP_NOFAIL);
 
 	xfs_log_item_init(tp->t_mountp, &attrdp->attrd_item, XFS_LI_ATTRD,
 			  &xfs_attrd_item_ops);
-- 
2.35.1

Re: [PATCH 02/16] xfs: initialise attrd item to zero

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> On the first allocation of a attrd item, xfs_trans_add_item() fires
> an assert like so:
> 
>  XFS (pmem0): EXPERIMENTAL logged extended attributes feature added.
> Use at your own risk!
>  XFS: Assertion failed: !test_bit(XFS_LI_DIRTY, &lip->li_flags),
> file: fs/xfs/xfs_trans.c, line: 683
>  ------------[ cut here ]------------
>  kernel BUG at fs/xfs/xfs_message.c:102!
>  Call Trace:
>   <TASK>
>   xfs_trans_add_item+0x17e/0x190
>   xfs_trans_get_attrd+0x67/0x90
>   xfs_attr_create_done+0x13/0x20
>   xfs_defer_finish_noroll+0x100/0x690
>   __xfs_trans_commit+0x144/0x330
>   xfs_trans_commit+0x10/0x20
>   xfs_attr_set+0x3e2/0x4c0
>   xfs_initxattrs+0xaa/0xe0
>   security_inode_init_security+0xb0/0x130
>   xfs_init_security+0x18/0x20
>   xfs_generic_create+0x13a/0x340
>   xfs_vn_create+0x17/0x20
>   path_openat+0xff3/0x12f0
>   do_filp_open+0xb2/0x150
> 
> The attrd log item is allocated via kmem_cache_alloc, and
> xfs_log_item_init() does not zero the entire log item structure - it
> assumes that the structure is already all zeros as it only
> initialises non-zero fields. Fix the attr items to be allocated
> via the *zalloc methods.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Ok, looks fine
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

> ---
>  fs/xfs/xfs_attr_item.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
> index 0e2ef0dedb28..b6561861ef01 100644
> --- a/fs/xfs/xfs_attr_item.c
> +++ b/fs/xfs/xfs_attr_item.c
> @@ -725,7 +725,7 @@ xfs_trans_get_attrd(struct xfs_trans		
> *tp,
>  
>  	ASSERT(tp != NULL);
>  
> -	attrdp = kmem_cache_alloc(xfs_attrd_cache, GFP_NOFS |
> __GFP_NOFAIL);
> +	attrdp = kmem_cache_zalloc(xfs_attrd_cache, GFP_NOFS |
> __GFP_NOFAIL);
>  
>  	xfs_log_item_init(tp->t_mountp, &attrdp->attrd_item,
> XFS_LI_ATTRD,
>  			  &xfs_attrd_item_ops);

[PATCH 03/16] xfs: make xattri_leaf_bp more useful

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

We currently set it and hold it when converting from short to leaf
form, then release it only to immediately look it back up again
to do the leaf insert.

Do a bit of refactoring to xfs_attr_leaf_try_add() to avoid this
messy handling of the newly allocated leaf buffer.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 50 +++++++++++++++++++++++++---------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index b3d918195160..a4b0b20a3bab 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -319,7 +319,15 @@ xfs_attr_leaf_addname(
 	int			error;
 
 	if (xfs_attr_is_leaf(dp)) {
+
+		/*
+		 * Use the leaf buffer we may already hold locked as a result of
+		 * a sf-to-leaf conversion. The held buffer is no longer valid
+		 * after this call, regardless of the result.
+		 */
 		error = xfs_attr_leaf_try_add(args, attr->xattri_leaf_bp);
+		attr->xattri_leaf_bp = NULL;
+
 		if (error == -ENOSPC) {
 			error = xfs_attr3_leaf_to_node(args);
 			if (error)
@@ -341,6 +349,8 @@ xfs_attr_leaf_addname(
 		}
 		next_state = XFS_DAS_FOUND_LBLK;
 	} else {
+		ASSERT(!attr->xattri_leaf_bp);
+
 		error = xfs_attr_node_addname_find_attr(attr);
 		if (error)
 			return error;
@@ -396,12 +406,6 @@ xfs_attr_set_iter(
 		 */
 		if (xfs_attr_is_shortform(dp))
 			return xfs_attr_sf_addname(attr);
-		if (attr->xattri_leaf_bp != NULL) {
-			xfs_trans_bhold_release(args->trans,
-						attr->xattri_leaf_bp);
-			attr->xattri_leaf_bp = NULL;
-		}
-
 		return xfs_attr_leaf_addname(attr);
 
 	case XFS_DAS_FOUND_LBLK:
@@ -992,18 +996,31 @@ xfs_attr_leaf_try_add(
 	struct xfs_da_args	*args,
 	struct xfs_buf		*bp)
 {
-	int			retval;
+	int			error;
 
 	/*
-	 * Look up the given attribute in the leaf block.  Figure out if
-	 * the given flags produce an error or call for an atomic rename.
+	 * If the caller provided a buffer to us, it is locked and held in
+	 * the transaction because it just did a shortform to leaf conversion.
+	 * Hence we don't need to read it again. Otherwise read in the leaf
+	 * buffer.
 	 */
-	retval = xfs_attr_leaf_hasname(args, &bp);
-	if (retval != -ENOATTR && retval != -EEXIST)
-		return retval;
-	if (retval == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
+	if (bp) {
+		xfs_trans_bhold_release(args->trans, bp);
+	} else {
+		error = xfs_attr3_leaf_read(args->trans, args->dp, 0, &bp);
+		if (error)
+			return error;
+	}
+
+	/*
+	 * Look up the xattr name to set the insertion point for the new xattr.
+	 */
+	error = xfs_attr3_leaf_lookup_int(bp, args);
+	if (error != -ENOATTR && error != -EEXIST)
 		goto out_brelse;
-	if (retval == -EEXIST) {
+	if (error == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
+		goto out_brelse;
+	if (error == -EEXIST) {
 		if (args->attr_flags & XATTR_CREATE)
 			goto out_brelse;
 
@@ -1023,14 +1040,11 @@ xfs_attr_leaf_try_add(
 		args->rmtvaluelen = 0;
 	}
 
-	/*
-	 * Add the attribute to the leaf block
-	 */
 	return xfs_attr3_leaf_add(bp, args);
 
 out_brelse:
 	xfs_trans_brelse(args->trans, bp);
-	return retval;
+	return error;
 }
 
 /*
-- 
2.35.1

Re: [PATCH 03/16] xfs: make xattri_leaf_bp more useful

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> We currently set it and hold it when converting from short to leaf
> form, then release it only to immediately look it back up again
> to do the leaf insert.
> 
> Do a bit of refactoring to xfs_attr_leaf_try_add() to avoid this
> messy handling of the newly allocated leaf buffer.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Ok, I think that looks good
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 50 +++++++++++++++++++++++++-------------
> --
>  1 file changed, 32 insertions(+), 18 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index b3d918195160..a4b0b20a3bab 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -319,7 +319,15 @@ xfs_attr_leaf_addname(
>  	int			error;
>  
>  	if (xfs_attr_is_leaf(dp)) {
> +
> +		/*
> +		 * Use the leaf buffer we may already hold locked as a
> result of
> +		 * a sf-to-leaf conversion. The held buffer is no
> longer valid
> +		 * after this call, regardless of the result.
> +		 */
>  		error = xfs_attr_leaf_try_add(args, attr-
> >xattri_leaf_bp);
> +		attr->xattri_leaf_bp = NULL;
> +
>  		if (error == -ENOSPC) {
>  			error = xfs_attr3_leaf_to_node(args);
>  			if (error)
> @@ -341,6 +349,8 @@ xfs_attr_leaf_addname(
>  		}
>  		next_state = XFS_DAS_FOUND_LBLK;
>  	} else {
> +		ASSERT(!attr->xattri_leaf_bp);
> +
>  		error = xfs_attr_node_addname_find_attr(attr);
>  		if (error)
>  			return error;
> @@ -396,12 +406,6 @@ xfs_attr_set_iter(
>  		 */
>  		if (xfs_attr_is_shortform(dp))
>  			return xfs_attr_sf_addname(attr);
> -		if (attr->xattri_leaf_bp != NULL) {
> -			xfs_trans_bhold_release(args->trans,
> -						attr->xattri_leaf_bp);
> -			attr->xattri_leaf_bp = NULL;
> -		}
> -
>  		return xfs_attr_leaf_addname(attr);
>  
>  	case XFS_DAS_FOUND_LBLK:
> @@ -992,18 +996,31 @@ xfs_attr_leaf_try_add(
>  	struct xfs_da_args	*args,
>  	struct xfs_buf		*bp)
>  {
> -	int			retval;
> +	int			error;
>  
>  	/*
> -	 * Look up the given attribute in the leaf block.  Figure out
> if
> -	 * the given flags produce an error or call for an atomic
> rename.
> +	 * If the caller provided a buffer to us, it is locked and held
> in
> +	 * the transaction because it just did a shortform to leaf
> conversion.
> +	 * Hence we don't need to read it again. Otherwise read in the
> leaf
> +	 * buffer.
>  	 */
> -	retval = xfs_attr_leaf_hasname(args, &bp);
> -	if (retval != -ENOATTR && retval != -EEXIST)
> -		return retval;
> -	if (retval == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
> +	if (bp) {
> +		xfs_trans_bhold_release(args->trans, bp);
> +	} else {
> +		error = xfs_attr3_leaf_read(args->trans, args->dp, 0,
> &bp);
> +		if (error)
> +			return error;
> +	}
> +
> +	/*
> +	 * Look up the xattr name to set the insertion point for the
> new xattr.
> +	 */
> +	error = xfs_attr3_leaf_lookup_int(bp, args);
> +	if (error != -ENOATTR && error != -EEXIST)
>  		goto out_brelse;
> -	if (retval == -EEXIST) {
> +	if (error == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
> +		goto out_brelse;
> +	if (error == -EEXIST) {
>  		if (args->attr_flags & XATTR_CREATE)
>  			goto out_brelse;
>  
> @@ -1023,14 +1040,11 @@ xfs_attr_leaf_try_add(
>  		args->rmtvaluelen = 0;
>  	}
>  
> -	/*
> -	 * Add the attribute to the leaf block
> -	 */
>  	return xfs_attr3_leaf_add(bp, args);
>  
>  out_brelse:
>  	xfs_trans_brelse(args->trans, bp);
> -	return retval;
> +	return error;
>  }
>  
>  /*

[PATCH 04/16] xfs: separate out initial attr_set states

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

We current use XFS_DAS_UNINIT for several steps in the attr_set
state machine. We use it for setting shortform xattrs, converting
from shortform to leaf, leaf add, leaf-to-node and leaf add. All of
these things are essentially known before we start the state machine
iterating, so we really should separate them out:

XFS_DAS_SF_ADD:
	- tries to do a shortform add
	- on success -> done
	- on ENOSPC converts to leaf, -> XFS_DAS_LEAF_ADD
	- on error, dies.

XFS_DAS_LEAF_ADD:
	- tries to do leaf add
	- on success:
		- inline attr -> done
		- remote xattr || REPLACE -> XFS_DAS_FOUND_LBLK
	- on ENOSPC converts to node, -> XFS_DAS_NODE_ADD
	- on error, dies

XFS_DAS_NODE_ADD:
	- tries to do node add
	- on success:
		- inline attr -> done
		- remote xattr || REPLACE -> XFS_DAS_FOUND_NBLK
	- on error, dies

This makes it easier to understand how the state machine starts
up and sets us up on the path to further state machine
simplifications.

This also converts the DAS state tracepoints to use strings rather
than numbers, as converting between enums and numbers requires
manual counting rather than just reading the name.

This also introduces a XFS_DAS_DONE state so that we can trace
successful operation completions easily.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 151 ++++++++++++++++++++++-----------------
 fs/xfs/libxfs/xfs_attr.h |  49 +++++++++----
 fs/xfs/xfs_trace.h       |  22 +++++-
 3 files changed, 140 insertions(+), 82 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index a4b0b20a3bab..b0bbf827fbca 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -59,7 +59,7 @@ STATIC int xfs_attr_leaf_try_add(struct xfs_da_args *args, struct xfs_buf *bp);
  */
 STATIC int xfs_attr_node_get(xfs_da_args_t *args);
 STATIC void xfs_attr_restore_rmt_blk(struct xfs_da_args *args);
-STATIC int xfs_attr_node_addname(struct xfs_attr_item *attr);
+static int xfs_attr_node_try_addname(struct xfs_attr_item *attr);
 STATIC int xfs_attr_node_addname_find_attr(struct xfs_attr_item *attr);
 STATIC int xfs_attr_node_addname_clear_incomplete(struct xfs_attr_item *attr);
 STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
@@ -224,6 +224,11 @@ xfs_init_attr_trans(
 	}
 }
 
+/*
+ * Add an attr to a shortform fork. If there is no space,
+ * xfs_attr_shortform_addname() will convert to leaf format and return -ENOSPC.
+ * to use.
+ */
 STATIC int
 xfs_attr_try_sf_addname(
 	struct xfs_inode	*dp,
@@ -268,7 +273,7 @@ xfs_attr_is_shortform(
 		ip->i_afp->if_nextents == 0);
 }
 
-STATIC int
+static int
 xfs_attr_sf_addname(
 	struct xfs_attr_item		*attr)
 {
@@ -276,14 +281,12 @@ xfs_attr_sf_addname(
 	struct xfs_inode		*dp = args->dp;
 	int				error = 0;
 
-	/*
-	 * Try to add the attr to the attribute list in the inode.
-	 */
 	error = xfs_attr_try_sf_addname(dp, args);
-
-	/* Should only be 0, -EEXIST or -ENOSPC */
-	if (error != -ENOSPC)
-		return error;
+	if (error != -ENOSPC) {
+		ASSERT(!error || error == -EEXIST);
+		attr->xattri_dela_state = XFS_DAS_DONE;
+		goto out;
+	}
 
 	/*
 	 * It won't fit in the shortform, transform to a leaf block.  GROT:
@@ -299,64 +302,42 @@ xfs_attr_sf_addname(
 	 * with the write verifier.
 	 */
 	xfs_trans_bhold(args->trans, attr->xattri_leaf_bp);
-
-	/*
-	 * We're still in XFS_DAS_UNINIT state here.  We've converted
-	 * the attr fork to leaf format and will restart with the leaf
-	 * add.
-	 */
-	trace_xfs_attr_sf_addname_return(XFS_DAS_UNINIT, args->dp);
-	return -EAGAIN;
+	attr->xattri_dela_state = XFS_DAS_LEAF_ADD;
+	error = -EAGAIN;
+out:
+	trace_xfs_attr_sf_addname_return(attr->xattri_dela_state, args->dp);
+	return error;
 }
 
-STATIC int
+static int
 xfs_attr_leaf_addname(
 	struct xfs_attr_item	*attr)
 {
 	struct xfs_da_args	*args = attr->xattri_da_args;
-	struct xfs_inode	*dp = args->dp;
-	enum xfs_delattr_state	next_state = XFS_DAS_UNINIT;
 	int			error;
 
-	if (xfs_attr_is_leaf(dp)) {
+	ASSERT(xfs_attr_is_leaf(args->dp));
 
-		/*
-		 * Use the leaf buffer we may already hold locked as a result of
-		 * a sf-to-leaf conversion. The held buffer is no longer valid
-		 * after this call, regardless of the result.
-		 */
-		error = xfs_attr_leaf_try_add(args, attr->xattri_leaf_bp);
-		attr->xattri_leaf_bp = NULL;
-
-		if (error == -ENOSPC) {
-			error = xfs_attr3_leaf_to_node(args);
-			if (error)
-				return error;
-
-			/*
-			 * Finish any deferred work items and roll the
-			 * transaction once more.  The goal here is to call
-			 * node_addname with the inode and transaction in the
-			 * same state (inode locked and joined, transaction
-			 * clean) no matter how we got to this step.
-			 *
-			 * At this point, we are still in XFS_DAS_UNINIT, but
-			 * when we come back, we'll be a node, so we'll fall
-			 * down into the node handling code below
-			 */
-			error = -EAGAIN;
-			goto out;
-		}
-		next_state = XFS_DAS_FOUND_LBLK;
-	} else {
-		ASSERT(!attr->xattri_leaf_bp);
+	/*
+	 * Use the leaf buffer we may already hold locked as a result of
+	 * a sf-to-leaf conversion. The held buffer is no longer valid
+	 * after this call, regardless of the result.
+	 */
+	error = xfs_attr_leaf_try_add(args, attr->xattri_leaf_bp);
+	attr->xattri_leaf_bp = NULL;
 
-		error = xfs_attr_node_addname_find_attr(attr);
+	if (error == -ENOSPC) {
+		error = xfs_attr3_leaf_to_node(args);
 		if (error)
 			return error;
 
-		next_state = XFS_DAS_FOUND_NBLK;
-		error = xfs_attr_node_addname(attr);
+		/*
+		 * We're not in leaf format anymore, so roll the transaction and
+		 * retry the add to the newly allocated node block.
+		 */
+		attr->xattri_dela_state = XFS_DAS_NODE_ADD;
+		error = -EAGAIN;
+		goto out;
 	}
 	if (error)
 		return error;
@@ -368,15 +349,46 @@ xfs_attr_leaf_addname(
 	 */
 	if (args->rmtblkno ||
 	    (args->op_flags & XFS_DA_OP_RENAME)) {
-		attr->xattri_dela_state = next_state;
+		attr->xattri_dela_state = XFS_DAS_FOUND_LBLK;
 		error = -EAGAIN;
+	} else {
+		attr->xattri_dela_state = XFS_DAS_DONE;
 	}
-
 out:
 	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state, args->dp);
 	return error;
 }
 
+static int
+xfs_attr_node_addname(
+	struct xfs_attr_item	*attr)
+{
+	struct xfs_da_args	*args = attr->xattri_da_args;
+	int			error;
+
+	ASSERT(!attr->xattri_leaf_bp);
+
+	error = xfs_attr_node_addname_find_attr(attr);
+	if (error)
+		return error;
+
+	error = xfs_attr_node_try_addname(attr);
+	if (error)
+		return error;
+
+	if (args->rmtblkno ||
+	    (args->op_flags & XFS_DA_OP_RENAME)) {
+		attr->xattri_dela_state = XFS_DAS_FOUND_NBLK;
+		error = -EAGAIN;
+	} else {
+		attr->xattri_dela_state = XFS_DAS_DONE;
+	}
+
+	trace_xfs_attr_node_addname_return(attr->xattri_dela_state, args->dp);
+	return error;
+}
+
+
 /*
  * Set the attribute specified in @args.
  * This routine is meant to function as a delayed operation, and may return
@@ -397,16 +409,14 @@ xfs_attr_set_iter(
 	/* State machine switch */
 	switch (attr->xattri_dela_state) {
 	case XFS_DAS_UNINIT:
-		/*
-		 * If the fork is shortform, attempt to add the attr. If there
-		 * is no space, this converts to leaf format and returns
-		 * -EAGAIN with the leaf buffer held across the roll. The caller
-		 * will deal with a transaction roll error, but otherwise
-		 * release the hold once we return with a clean transaction.
-		 */
-		if (xfs_attr_is_shortform(dp))
-			return xfs_attr_sf_addname(attr);
+		ASSERT(0);
+		return -EFSCORRUPTED;
+	case XFS_DAS_SF_ADD:
+		return xfs_attr_sf_addname(attr);
+	case XFS_DAS_LEAF_ADD:
 		return xfs_attr_leaf_addname(attr);
+	case XFS_DAS_NODE_ADD:
+		return xfs_attr_node_addname(attr);
 
 	case XFS_DAS_FOUND_LBLK:
 		/*
@@ -874,6 +884,13 @@ xfs_attr_set_deferred(
 	if (error)
 		return error;
 
+	if (xfs_attr_is_shortform(args->dp))
+		new->xattri_dela_state = XFS_DAS_SF_ADD;
+	else if (xfs_attr_is_leaf(args->dp))
+		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
+	else
+		new->xattri_dela_state = XFS_DAS_NODE_ADD;
+
 	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
 
 	return 0;
@@ -1233,8 +1250,8 @@ xfs_attr_node_addname_find_attr(
  * to handle this, and recall the function until a successful error code is
  *returned.
  */
-STATIC int
-xfs_attr_node_addname(
+static int
+xfs_attr_node_try_addname(
 	struct xfs_attr_item		*attr)
 {
 	struct xfs_da_args		*args = attr->xattri_da_args;
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index f6c13d2bfbcd..fc2a177f6994 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -443,21 +443,44 @@ struct xfs_attr_list_context {
  * to where it was and resume executing where it left off.
  */
 enum xfs_delattr_state {
-	XFS_DAS_UNINIT		= 0,  /* No state has been set yet */
-	XFS_DAS_RMTBLK,		      /* Removing remote blks */
-	XFS_DAS_RM_NAME,	      /* Remove attr name */
-	XFS_DAS_RM_SHRINK,	      /* We are shrinking the tree */
-	XFS_DAS_FOUND_LBLK,	      /* We found leaf blk for attr */
-	XFS_DAS_FOUND_NBLK,	      /* We found node blk for attr */
-	XFS_DAS_FLIP_LFLAG,	      /* Flipped leaf INCOMPLETE attr flag */
-	XFS_DAS_RM_LBLK,	      /* A rename is removing leaf blocks */
-	XFS_DAS_RD_LEAF,	      /* Read in the new leaf */
-	XFS_DAS_ALLOC_NODE,	      /* We are allocating node blocks */
-	XFS_DAS_FLIP_NFLAG,	      /* Flipped node INCOMPLETE attr flag */
-	XFS_DAS_RM_NBLK,	      /* A rename is removing node blocks */
-	XFS_DAS_CLR_FLAG,	      /* Clear incomplete flag */
+	XFS_DAS_UNINIT		= 0,	/* No state has been set yet */
+	XFS_DAS_SF_ADD,			/* Initial shortform set iter state */
+	XFS_DAS_LEAF_ADD,		/* Initial leaf form set iter state */
+	XFS_DAS_NODE_ADD,		/* Initial node form set iter state */
+	XFS_DAS_RMTBLK,			/* Removing remote blks */
+	XFS_DAS_RM_NAME,		/* Remove attr name */
+	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree */
+	XFS_DAS_FOUND_LBLK,		/* We found leaf blk for attr */
+	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr */
+	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE attr flag */
+	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks */
+	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
+	XFS_DAS_ALLOC_NODE,		/* We are allocating node blocks */
+	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE attr flag */
+	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks */
+	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
+	XFS_DAS_DONE,			/* finished operation */
 };
 
+#define XFS_DAS_STRINGS	\
+	{ XFS_DAS_UNINIT,	"XFS_DAS_UNINIT" }, \
+	{ XFS_DAS_SF_ADD,	"XFS_DAS_SF_ADD" }, \
+	{ XFS_DAS_LEAF_ADD,	"XFS_DAS_LEAF_ADD" }, \
+	{ XFS_DAS_NODE_ADD,	"XFS_DAS_NODE_ADD" }, \
+	{ XFS_DAS_RMTBLK,	"XFS_DAS_RMTBLK" }, \
+	{ XFS_DAS_RM_NAME,	"XFS_DAS_RM_NAME" }, \
+	{ XFS_DAS_RM_SHRINK,	"XFS_DAS_RM_SHRINK" }, \
+	{ XFS_DAS_FOUND_LBLK,	"XFS_DAS_FOUND_LBLK" }, \
+	{ XFS_DAS_FOUND_NBLK,	"XFS_DAS_FOUND_NBLK" }, \
+	{ XFS_DAS_FLIP_LFLAG,	"XFS_DAS_FLIP_LFLAG" }, \
+	{ XFS_DAS_RM_LBLK,	"XFS_DAS_RM_LBLK" }, \
+	{ XFS_DAS_RD_LEAF,	"XFS_DAS_RD_LEAF" }, \
+	{ XFS_DAS_ALLOC_NODE,	"XFS_DAS_ALLOC_NODE" }, \
+	{ XFS_DAS_FLIP_NFLAG,	"XFS_DAS_FLIP_NFLAG" }, \
+	{ XFS_DAS_RM_NBLK,	"XFS_DAS_RM_NBLK" }, \
+	{ XFS_DAS_CLR_FLAG,	"XFS_DAS_CLR_FLAG" }, \
+	{ XFS_DAS_DONE,		"XFS_DAS_DONE" }
+
 /*
  * Defines for xfs_attr_item.xattri_flags
  */
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 51e45341cf76..9fc3fe334b5f 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -4098,6 +4098,23 @@ DEFINE_ICLOG_EVENT(xlog_iclog_want_sync);
 DEFINE_ICLOG_EVENT(xlog_iclog_wait_on);
 DEFINE_ICLOG_EVENT(xlog_iclog_write);
 
+TRACE_DEFINE_ENUM(XFS_DAS_UNINIT);
+TRACE_DEFINE_ENUM(XFS_DAS_SF_ADD);
+TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ADD);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
+TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
+TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
+TRACE_DEFINE_ENUM(XFS_DAS_FOUND_LBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_FOUND_NBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_FLIP_LFLAG);
+TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
+TRACE_DEFINE_ENUM(XFS_DAS_ALLOC_NODE);
+TRACE_DEFINE_ENUM(XFS_DAS_FLIP_NFLAG);
+TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
+
 DECLARE_EVENT_CLASS(xfs_das_state_class,
 	TP_PROTO(int das, struct xfs_inode *ip),
 	TP_ARGS(das, ip),
@@ -4109,8 +4126,9 @@ DECLARE_EVENT_CLASS(xfs_das_state_class,
 		__entry->das = das;
 		__entry->ino = ip->i_ino;
 	),
-	TP_printk("state change %d ino 0x%llx",
-		  __entry->das, __entry->ino)
+	TP_printk("state change %s ino 0x%llx",
+		  __print_symbolic(__entry->das, XFS_DAS_STRINGS),
+		  __entry->ino)
 )
 
 #define DEFINE_DAS_STATE_EVENT(name) \
-- 
2.35.1

Re: [PATCH 04/16] xfs: separate out initial attr_set states

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> We current use XFS_DAS_UNINIT for several steps in the attr_set
> state machine. We use it for setting shortform xattrs, converting
> from shortform to leaf, leaf add, leaf-to-node and leaf add. All of
> these things are essentially known before we start the state machine
> iterating, so we really should separate them out:
> 
> XFS_DAS_SF_ADD:
> 	- tries to do a shortform add
> 	- on success -> done
> 	- on ENOSPC converts to leaf, -> XFS_DAS_LEAF_ADD
> 	- on error, dies.
> 
> XFS_DAS_LEAF_ADD:
> 	- tries to do leaf add
> 	- on success:
> 		- inline attr -> done
> 		- remote xattr || REPLACE -> XFS_DAS_FOUND_LBLK
> 	- on ENOSPC converts to node, -> XFS_DAS_NODE_ADD
> 	- on error, dies
> 
> XFS_DAS_NODE_ADD:
> 	- tries to do node add
> 	- on success:
> 		- inline attr -> done
> 		- remote xattr || REPLACE -> XFS_DAS_FOUND_NBLK
> 	- on error, dies
> 
> This makes it easier to understand how the state machine starts
> up and sets us up on the path to further state machine
> simplifications.
> 
> This also converts the DAS state tracepoints to use strings rather
> than numbers, as converting between enums and numbers requires
> manual counting rather than just reading the name.
> 
> This also introduces a XFS_DAS_DONE state so that we can trace
> successful operation completions easily.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 151 ++++++++++++++++++++++---------------
> --
>  fs/xfs/libxfs/xfs_attr.h |  49 +++++++++----
>  fs/xfs/xfs_trace.h       |  22 +++++-
>  3 files changed, 140 insertions(+), 82 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index a4b0b20a3bab..b0bbf827fbca 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -59,7 +59,7 @@ STATIC int xfs_attr_leaf_try_add(struct xfs_da_args
> *args, struct xfs_buf *bp);
>   */
>  STATIC int xfs_attr_node_get(xfs_da_args_t *args);
>  STATIC void xfs_attr_restore_rmt_blk(struct xfs_da_args *args);
> -STATIC int xfs_attr_node_addname(struct xfs_attr_item *attr);
> +static int xfs_attr_node_try_addname(struct xfs_attr_item *attr);
>  STATIC int xfs_attr_node_addname_find_attr(struct xfs_attr_item
> *attr);
>  STATIC int xfs_attr_node_addname_clear_incomplete(struct
> xfs_attr_item *attr);
>  STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
> @@ -224,6 +224,11 @@ xfs_init_attr_trans(
>  	}
>  }
>  
> +/*
> + * Add an attr to a shortform fork. If there is no space,
> + * xfs_attr_shortform_addname() will convert to leaf format and
> return -ENOSPC.
> + * to use.
> + */
>  STATIC int
>  xfs_attr_try_sf_addname(
>  	struct xfs_inode	*dp,
> @@ -268,7 +273,7 @@ xfs_attr_is_shortform(
>  		ip->i_afp->if_nextents == 0);
>  }
>  
> -STATIC int
> +static int
>  xfs_attr_sf_addname(
>  	struct xfs_attr_item		*attr)
>  {
> @@ -276,14 +281,12 @@ xfs_attr_sf_addname(
>  	struct xfs_inode		*dp = args->dp;
>  	int				error = 0;
>  
> -	/*
> -	 * Try to add the attr to the attribute list in the inode.
> -	 */
>  	error = xfs_attr_try_sf_addname(dp, args);
> -
> -	/* Should only be 0, -EEXIST or -ENOSPC */
> -	if (error != -ENOSPC)
> -		return error;
> +	if (error != -ENOSPC) {
> +		ASSERT(!error || error == -EEXIST);
> +		attr->xattri_dela_state = XFS_DAS_DONE;
> +		goto out;
> +	}
>  
>  	/*
>  	 * It won't fit in the shortform, transform to a leaf
> block.  GROT:
> @@ -299,64 +302,42 @@ xfs_attr_sf_addname(
>  	 * with the write verifier.
>  	 */
>  	xfs_trans_bhold(args->trans, attr->xattri_leaf_bp);
> -
> -	/*
> -	 * We're still in XFS_DAS_UNINIT state here.  We've converted
> -	 * the attr fork to leaf format and will restart with the leaf
> -	 * add.
> -	 */
> -	trace_xfs_attr_sf_addname_return(XFS_DAS_UNINIT, args->dp);
> -	return -EAGAIN;
> +	attr->xattri_dela_state = XFS_DAS_LEAF_ADD;
> +	error = -EAGAIN;
> +out:
> +	trace_xfs_attr_sf_addname_return(attr->xattri_dela_state, args-
> >dp);
> +	return error;
>  }
>  
> -STATIC int
> +static int
>  xfs_attr_leaf_addname(
>  	struct xfs_attr_item	*attr)
>  {
>  	struct xfs_da_args	*args = attr->xattri_da_args;
> -	struct xfs_inode	*dp = args->dp;
> -	enum xfs_delattr_state	next_state = XFS_DAS_UNINIT;
>  	int			error;
>  
> -	if (xfs_attr_is_leaf(dp)) {
> +	ASSERT(xfs_attr_is_leaf(args->dp));
>  
> -		/*
> -		 * Use the leaf buffer we may already hold locked as a
> result of
> -		 * a sf-to-leaf conversion. The held buffer is no
> longer valid
> -		 * after this call, regardless of the result.
> -		 */
> -		error = xfs_attr_leaf_try_add(args, attr-
> >xattri_leaf_bp);
> -		attr->xattri_leaf_bp = NULL;
> -
> -		if (error == -ENOSPC) {
> -			error = xfs_attr3_leaf_to_node(args);
> -			if (error)
> -				return error;
> -
> -			/*
> -			 * Finish any deferred work items and roll the
> -			 * transaction once more.  The goal here is to
> call
> -			 * node_addname with the inode and transaction
> in the
> -			 * same state (inode locked and joined,
> transaction
> -			 * clean) no matter how we got to this step.
> -			 *
> -			 * At this point, we are still in
> XFS_DAS_UNINIT, but
> -			 * when we come back, we'll be a node, so we'll
> fall
> -			 * down into the node handling code below
> -			 */
> -			error = -EAGAIN;
> -			goto out;
> -		}
> -		next_state = XFS_DAS_FOUND_LBLK;
> -	} else {
> -		ASSERT(!attr->xattri_leaf_bp);
> +	/*
> +	 * Use the leaf buffer we may already hold locked as a result
> of
> +	 * a sf-to-leaf conversion. The held buffer is no longer valid
> +	 * after this call, regardless of the result.
> +	 */
> +	error = xfs_attr_leaf_try_add(args, attr->xattri_leaf_bp);
> +	attr->xattri_leaf_bp = NULL;
>  
> -		error = xfs_attr_node_addname_find_attr(attr);
> +	if (error == -ENOSPC) {
> +		error = xfs_attr3_leaf_to_node(args);
>  		if (error)
>  			return error;
>  
> -		next_state = XFS_DAS_FOUND_NBLK;
> -		error = xfs_attr_node_addname(attr);
> +		/*
> +		 * We're not in leaf format anymore, so roll the
> transaction and
> +		 * retry the add to the newly allocated node block.
> +		 */
> +		attr->xattri_dela_state = XFS_DAS_NODE_ADD;
> +		error = -EAGAIN;
> +		goto out;
>  	}
>  	if (error)
>  		return error;
> @@ -368,15 +349,46 @@ xfs_attr_leaf_addname(
>  	 */
>  	if (args->rmtblkno ||
>  	    (args->op_flags & XFS_DA_OP_RENAME)) {
> -		attr->xattri_dela_state = next_state;
> +		attr->xattri_dela_state = XFS_DAS_FOUND_LBLK;
>  		error = -EAGAIN;
> +	} else {
> +		attr->xattri_dela_state = XFS_DAS_DONE;
>  	}
> -
>  out:
>  	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state,
> args->dp);
>  	return error;
>  }
>  
> +static int
> +xfs_attr_node_addname(
> +	struct xfs_attr_item	*attr)
> +{
> +	struct xfs_da_args	*args = attr->xattri_da_args;
> +	int			error;
> +
> +	ASSERT(!attr->xattri_leaf_bp);
> +
> +	error = xfs_attr_node_addname_find_attr(attr);
> +	if (error)
> +		return error;
> +
> +	error = xfs_attr_node_try_addname(attr);
> +	if (error)
> +		return error;
> +
> +	if (args->rmtblkno ||
> +	    (args->op_flags & XFS_DA_OP_RENAME)) {
> +		attr->xattri_dela_state = XFS_DAS_FOUND_NBLK;
> +		error = -EAGAIN;
> +	} else {
> +		attr->xattri_dela_state = XFS_DAS_DONE;
> +	}
> +
> +	trace_xfs_attr_node_addname_return(attr->xattri_dela_state,
> args->dp);
> +	return error;
> +}
> +
> +
>  /*
>   * Set the attribute specified in @args.
>   * This routine is meant to function as a delayed operation, and may
> return
> @@ -397,16 +409,14 @@ xfs_attr_set_iter(
>  	/* State machine switch */
>  	switch (attr->xattri_dela_state) {
>  	case XFS_DAS_UNINIT:
> -		/*
> -		 * If the fork is shortform, attempt to add the attr.
> If there
> -		 * is no space, this converts to leaf format and
> returns
> -		 * -EAGAIN with the leaf buffer held across the roll.
> The caller
> -		 * will deal with a transaction roll error, but
> otherwise
> -		 * release the hold once we return with a clean
> transaction.
> -		 */
> -		if (xfs_attr_is_shortform(dp))
> -			return xfs_attr_sf_addname(attr);
> +		ASSERT(0);
> +		return -EFSCORRUPTED;
> +	case XFS_DAS_SF_ADD:
> +		return xfs_attr_sf_addname(attr);
> +	case XFS_DAS_LEAF_ADD:
>  		return xfs_attr_leaf_addname(attr);
> +	case XFS_DAS_NODE_ADD:
> +		return xfs_attr_node_addname(attr);
>  
>  	case XFS_DAS_FOUND_LBLK:
>  		/*
> @@ -874,6 +884,13 @@ xfs_attr_set_deferred(
>  	if (error)
>  		return error;
>  
> +	if (xfs_attr_is_shortform(args->dp))
> +		new->xattri_dela_state = XFS_DAS_SF_ADD;
> +	else if (xfs_attr_is_leaf(args->dp))
> +		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
> +	else
> +		new->xattri_dela_state = XFS_DAS_NODE_ADD;
> +
Mmmm, I dont know about putting this part here, because the
xfs_attr_*_deferred routines do not get called during a replay, so this
initial state config would get missed.  If you scoot it up into
the xfs_attr_item_init call just a few lines up, then things should be
fine since both code path start with that.  Rest looks ok though.

Allison

>  	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
>  
>  	return 0;
> @@ -1233,8 +1250,8 @@ xfs_attr_node_addname_find_attr(
>   * to handle this, and recall the function until a successful error
> code is
>   *returned.
>   */
> -STATIC int
> -xfs_attr_node_addname(
> +static int
> +xfs_attr_node_try_addname(
>  	struct xfs_attr_item		*attr)
>  {
>  	struct xfs_da_args		*args = attr->xattri_da_args;
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index f6c13d2bfbcd..fc2a177f6994 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -443,21 +443,44 @@ struct xfs_attr_list_context {
>   * to where it was and resume executing where it left off.
>   */
>  enum xfs_delattr_state {
> -	XFS_DAS_UNINIT		= 0,  /* No state has been set yet */
> -	XFS_DAS_RMTBLK,		      /* Removing remote blks */
> -	XFS_DAS_RM_NAME,	      /* Remove attr name */
> -	XFS_DAS_RM_SHRINK,	      /* We are shrinking the tree */
> -	XFS_DAS_FOUND_LBLK,	      /* We found leaf blk for attr
> */
> -	XFS_DAS_FOUND_NBLK,	      /* We found node blk for attr
> */
> -	XFS_DAS_FLIP_LFLAG,	      /* Flipped leaf INCOMPLETE attr
> flag */
> -	XFS_DAS_RM_LBLK,	      /* A rename is removing leaf blocks */
> -	XFS_DAS_RD_LEAF,	      /* Read in the new leaf */
> -	XFS_DAS_ALLOC_NODE,	      /* We are allocating node
> blocks */
> -	XFS_DAS_FLIP_NFLAG,	      /* Flipped node INCOMPLETE attr
> flag */
> -	XFS_DAS_RM_NBLK,	      /* A rename is removing node blocks */
> -	XFS_DAS_CLR_FLAG,	      /* Clear incomplete flag */
> +	XFS_DAS_UNINIT		= 0,	/* No state has been set yet
> */
> +	XFS_DAS_SF_ADD,			/* Initial shortform set iter
> state */
> +	XFS_DAS_LEAF_ADD,		/* Initial leaf form set iter state
> */
> +	XFS_DAS_NODE_ADD,		/* Initial node form set iter state
> */
> +	XFS_DAS_RMTBLK,			/* Removing remote blks */
> +	XFS_DAS_RM_NAME,		/* Remove attr name */
> +	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree
> */
> +	XFS_DAS_FOUND_LBLK,		/* We found leaf blk for attr
> */
> +	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr
> */
> +	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE
> attr flag */
> +	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks
> */
> +	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
> +	XFS_DAS_ALLOC_NODE,		/* We are allocating node
> blocks */
> +	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE
> attr flag */
> +	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks
> */
> +	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
> +	XFS_DAS_DONE,			/* finished operation */
>  };
>  
> +#define XFS_DAS_STRINGS	\
> +	{ XFS_DAS_UNINIT,	"XFS_DAS_UNINIT" }, \
> +	{ XFS_DAS_SF_ADD,	"XFS_DAS_SF_ADD" }, \
> +	{ XFS_DAS_LEAF_ADD,	"XFS_DAS_LEAF_ADD" }, \
> +	{ XFS_DAS_NODE_ADD,	"XFS_DAS_NODE_ADD" }, \
> +	{ XFS_DAS_RMTBLK,	"XFS_DAS_RMTBLK" }, \
> +	{ XFS_DAS_RM_NAME,	"XFS_DAS_RM_NAME" }, \
> +	{ XFS_DAS_RM_SHRINK,	"XFS_DAS_RM_SHRINK" }, \
> +	{ XFS_DAS_FOUND_LBLK,	"XFS_DAS_FOUND_LBLK" }, \
> +	{ XFS_DAS_FOUND_NBLK,	"XFS_DAS_FOUND_NBLK" }, \
> +	{ XFS_DAS_FLIP_LFLAG,	"XFS_DAS_FLIP_LFLAG" }, \
> +	{ XFS_DAS_RM_LBLK,	"XFS_DAS_RM_LBLK" }, \
> +	{ XFS_DAS_RD_LEAF,	"XFS_DAS_RD_LEAF" }, \
> +	{ XFS_DAS_ALLOC_NODE,	"XFS_DAS_ALLOC_NODE" }, \
> +	{ XFS_DAS_FLIP_NFLAG,	"XFS_DAS_FLIP_NFLAG" }, \
> +	{ XFS_DAS_RM_NBLK,	"XFS_DAS_RM_NBLK" }, \
> +	{ XFS_DAS_CLR_FLAG,	"XFS_DAS_CLR_FLAG" }, \
> +	{ XFS_DAS_DONE,		"XFS_DAS_DONE" }
> +
>  /*
>   * Defines for xfs_attr_item.xattri_flags
>   */
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 51e45341cf76..9fc3fe334b5f 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4098,6 +4098,23 @@ DEFINE_ICLOG_EVENT(xlog_iclog_want_sync);
>  DEFINE_ICLOG_EVENT(xlog_iclog_wait_on);
>  DEFINE_ICLOG_EVENT(xlog_iclog_write);
>  
> +TRACE_DEFINE_ENUM(XFS_DAS_UNINIT);
> +TRACE_DEFINE_ENUM(XFS_DAS_SF_ADD);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ADD);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
> +TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
> +TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
> +TRACE_DEFINE_ENUM(XFS_DAS_FOUND_LBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_FOUND_NBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_FLIP_LFLAG);
> +TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
> +TRACE_DEFINE_ENUM(XFS_DAS_ALLOC_NODE);
> +TRACE_DEFINE_ENUM(XFS_DAS_FLIP_NFLAG);
> +TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
> +
>  DECLARE_EVENT_CLASS(xfs_das_state_class,
>  	TP_PROTO(int das, struct xfs_inode *ip),
>  	TP_ARGS(das, ip),
> @@ -4109,8 +4126,9 @@ DECLARE_EVENT_CLASS(xfs_das_state_class,
>  		__entry->das = das;
>  		__entry->ino = ip->i_ino;
>  	),
> -	TP_printk("state change %d ino 0x%llx",
> -		  __entry->das, __entry->ino)
> +	TP_printk("state change %s ino 0x%llx",
> +		  __print_symbolic(__entry->das, XFS_DAS_STRINGS),
> +		  __entry->ino)
>  )
>  
>  #define DEFINE_DAS_STATE_EVENT(name) \

Re: [PATCH 04/16] xfs: separate out initial attr_set states

[Dave Chinner]

On Thu, Apr 21, 2022 at 05:38:03PM -0700, Alli wrote:
> On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > We current use XFS_DAS_UNINIT for several steps in the attr_set
> > state machine. We use it for setting shortform xattrs, converting
> > from shortform to leaf, leaf add, leaf-to-node and leaf add. All of
> > these things are essentially known before we start the state machine
> > iterating, so we really should separate them out:
> > 
> > XFS_DAS_SF_ADD:
> > 	- tries to do a shortform add
> > 	- on success -> done
> > 	- on ENOSPC converts to leaf, -> XFS_DAS_LEAF_ADD
> > 	- on error, dies.
> > 
> > XFS_DAS_LEAF_ADD:
> > 	- tries to do leaf add
> > 	- on success:
> > 		- inline attr -> done
> > 		- remote xattr || REPLACE -> XFS_DAS_FOUND_LBLK
> > 	- on ENOSPC converts to node, -> XFS_DAS_NODE_ADD
> > 	- on error, dies
> > 
> > XFS_DAS_NODE_ADD:
> > 	- tries to do node add
> > 	- on success:
> > 		- inline attr -> done
> > 		- remote xattr || REPLACE -> XFS_DAS_FOUND_NBLK
> > 	- on error, dies
....
> > @@ -874,6 +884,13 @@ xfs_attr_set_deferred(
> >  	if (error)
> >  		return error;
> >  
> > +	if (xfs_attr_is_shortform(args->dp))
> > +		new->xattri_dela_state = XFS_DAS_SF_ADD;
> > +	else if (xfs_attr_is_leaf(args->dp))
> > +		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
> > +	else
> > +		new->xattri_dela_state = XFS_DAS_NODE_ADD;
> > +
> Mmmm, I dont know about putting this part here, because the
> xfs_attr_*_deferred routines do not get called during a replay, so this
> initial state config would get missed.  If you scoot it up into
> the xfs_attr_item_init call just a few lines up, then things should be
> fine since both code path start with that.  Rest looks ok though.

Yeah, recovery gets fixed up later on in the patchset. I managed
to get this through several rounds of fstests auto group and
several iterations of recoveryloop testing before I actually had
recovery hit the ASSERT(state != XFS_DAS_UNINIT) case....

I'm just getting back to this series now, so I'll look to clean this
aspect of it up.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

[PATCH 05/16] xfs: kill XFS_DAC_LEAF_ADDNAME_INIT

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

We re-enter the XFS_DAS_FOUND_LBLK state when we have to allocate
multiple extents for a remote xattr. We currently have a flag
called XFS_DAC_LEAF_ADDNAME_INIT to avoid running the remote attr
hole finding code more than once.

However, for the node format tree, we have a separate state for this
so we never reenter the state machine at XFS_DAS_FOUND_NBLK and so
it does not need a special flag to skip over the remote attr hold
finding code.

Convert the leaf block code to use the same state machine as the
node blocks and kill the  XFS_DAC_LEAF_ADDNAME_INIT flag.

This further points out that this "ALLOC" state is only traversed
if we have remote xattrs or we are doing a rename operation. Rename
both the leaf and node alloc states to _ALLOC_RMT to indicate they
are iterating to do allocation of remote xattr blocks.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 45 ++++++++++++++++++++--------------------
 fs/xfs/libxfs/xfs_attr.h |  6 ++++--
 fs/xfs/xfs_trace.h       |  3 ++-
 3 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index b0bbf827fbca..fed476bd048e 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -419,40 +419,41 @@ xfs_attr_set_iter(
 		return xfs_attr_node_addname(attr);
 
 	case XFS_DAS_FOUND_LBLK:
+		/*
+		 * Find space for remote blocks and fall into the allocation
+		 * state.
+		 */
+		if (args->rmtblkno > 0) {
+			error = xfs_attr_rmtval_find_space(attr);
+			if (error)
+				return error;
+		}
+		attr->xattri_dela_state = XFS_DAS_LEAF_ALLOC_RMT;
+		fallthrough;
+	case XFS_DAS_LEAF_ALLOC_RMT:
+
 		/*
 		 * If there was an out-of-line value, allocate the blocks we
 		 * identified for its storage and copy the value.  This is done
 		 * after we create the attribute so that we don't overflow the
 		 * maximum size of a transaction and/or hit a deadlock.
 		 */
-
-		/* Open coded xfs_attr_rmtval_set without trans handling */
-		if ((attr->xattri_flags & XFS_DAC_LEAF_ADDNAME_INIT) == 0) {
-			attr->xattri_flags |= XFS_DAC_LEAF_ADDNAME_INIT;
-			if (args->rmtblkno > 0) {
-				error = xfs_attr_rmtval_find_space(attr);
+		if (args->rmtblkno > 0) {
+			if (attr->xattri_blkcnt > 0) {
+				error = xfs_attr_rmtval_set_blk(attr);
 				if (error)
 					return error;
+				trace_xfs_attr_set_iter_return(
+						attr->xattri_dela_state,
+						args->dp);
+				return -EAGAIN;
 			}
-		}
 
-		/*
-		 * Repeat allocating remote blocks for the attr value until
-		 * blkcnt drops to zero.
-		 */
-		if (attr->xattri_blkcnt > 0) {
-			error = xfs_attr_rmtval_set_blk(attr);
+			error = xfs_attr_rmtval_set_value(args);
 			if (error)
 				return error;
-			trace_xfs_attr_set_iter_return(attr->xattri_dela_state,
-						       args->dp);
-			return -EAGAIN;
 		}
 
-		error = xfs_attr_rmtval_set_value(args);
-		if (error)
-			return error;
-
 		/*
 		 * If this is not a rename, clear the incomplete flag and we're
 		 * done.
@@ -547,15 +548,15 @@ xfs_attr_set_iter(
 				return error;
 		}
 
+		attr->xattri_dela_state = XFS_DAS_NODE_ALLOC_RMT;
 		fallthrough;
-	case XFS_DAS_ALLOC_NODE:
+	case XFS_DAS_NODE_ALLOC_RMT:
 		/*
 		 * If there was an out-of-line value, allocate the blocks we
 		 * identified for its storage and copy the value.  This is done
 		 * after we create the attribute so that we don't overflow the
 		 * maximum size of a transaction and/or hit a deadlock.
 		 */
-		attr->xattri_dela_state = XFS_DAS_ALLOC_NODE;
 		if (args->rmtblkno > 0) {
 			if (attr->xattri_blkcnt > 0) {
 				error = xfs_attr_rmtval_set_blk(attr);
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index fc2a177f6994..184dca735cf3 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -451,11 +451,12 @@ enum xfs_delattr_state {
 	XFS_DAS_RM_NAME,		/* Remove attr name */
 	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree */
 	XFS_DAS_FOUND_LBLK,		/* We found leaf blk for attr */
+	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr */
+	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE attr flag */
 	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks */
 	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
-	XFS_DAS_ALLOC_NODE,		/* We are allocating node blocks */
 	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE attr flag */
 	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks */
 	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
@@ -471,11 +472,12 @@ enum xfs_delattr_state {
 	{ XFS_DAS_RM_NAME,	"XFS_DAS_RM_NAME" }, \
 	{ XFS_DAS_RM_SHRINK,	"XFS_DAS_RM_SHRINK" }, \
 	{ XFS_DAS_FOUND_LBLK,	"XFS_DAS_FOUND_LBLK" }, \
+	{ XFS_DAS_LEAF_ALLOC_RMT, "XFS_DAS_LEAF_ALLOC_RMT" }, \
 	{ XFS_DAS_FOUND_NBLK,	"XFS_DAS_FOUND_NBLK" }, \
+	{ XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" },  \
 	{ XFS_DAS_FLIP_LFLAG,	"XFS_DAS_FLIP_LFLAG" }, \
 	{ XFS_DAS_RM_LBLK,	"XFS_DAS_RM_LBLK" }, \
 	{ XFS_DAS_RD_LEAF,	"XFS_DAS_RD_LEAF" }, \
-	{ XFS_DAS_ALLOC_NODE,	"XFS_DAS_ALLOC_NODE" }, \
 	{ XFS_DAS_FLIP_NFLAG,	"XFS_DAS_FLIP_NFLAG" }, \
 	{ XFS_DAS_RM_NBLK,	"XFS_DAS_RM_NBLK" }, \
 	{ XFS_DAS_CLR_FLAG,	"XFS_DAS_CLR_FLAG" }, \
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 9fc3fe334b5f..8739cc1e0561 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -4106,11 +4106,12 @@ TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
 TRACE_DEFINE_ENUM(XFS_DAS_FOUND_LBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_FOUND_NBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_FLIP_LFLAG);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
 TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
-TRACE_DEFINE_ENUM(XFS_DAS_ALLOC_NODE);
 TRACE_DEFINE_ENUM(XFS_DAS_FLIP_NFLAG);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
 TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
-- 
2.35.1

Re: [PATCH 05/16] xfs: kill XFS_DAC_LEAF_ADDNAME_INIT

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> We re-enter the XFS_DAS_FOUND_LBLK state when we have to allocate
> multiple extents for a remote xattr. We currently have a flag
> called XFS_DAC_LEAF_ADDNAME_INIT to avoid running the remote attr
> hole finding code more than once.
> 
> However, for the node format tree, we have a separate state for this
> so we never reenter the state machine at XFS_DAS_FOUND_NBLK and so
> it does not need a special flag to skip over the remote attr hold
> finding code.
> 
> Convert the leaf block code to use the same state machine as the
> node blocks and kill the  XFS_DAC_LEAF_ADDNAME_INIT flag.
> 
> This further points out that this "ALLOC" state is only traversed
> if we have remote xattrs or we are doing a rename operation. Rename
> both the leaf and node alloc states to _ALLOC_RMT to indicate they
> are iterating to do allocation of remote xattr blocks.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Looks ok to me
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

> ---
>  fs/xfs/libxfs/xfs_attr.c | 45 ++++++++++++++++++++----------------
> ----
>  fs/xfs/libxfs/xfs_attr.h |  6 ++++--
>  fs/xfs/xfs_trace.h       |  3 ++-
>  3 files changed, 29 insertions(+), 25 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index b0bbf827fbca..fed476bd048e 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -419,40 +419,41 @@ xfs_attr_set_iter(
>  		return xfs_attr_node_addname(attr);
>  
>  	case XFS_DAS_FOUND_LBLK:
> +		/*
> +		 * Find space for remote blocks and fall into the
> allocation
> +		 * state.
> +		 */
> +		if (args->rmtblkno > 0) {
> +			error = xfs_attr_rmtval_find_space(attr);
> +			if (error)
> +				return error;
> +		}
> +		attr->xattri_dela_state = XFS_DAS_LEAF_ALLOC_RMT;
> +		fallthrough;
> +	case XFS_DAS_LEAF_ALLOC_RMT:
> +
>  		/*
>  		 * If there was an out-of-line value, allocate the
> blocks we
>  		 * identified for its storage and copy the value.  This
> is done
>  		 * after we create the attribute so that we don't
> overflow the
>  		 * maximum size of a transaction and/or hit a deadlock.
>  		 */
> -
> -		/* Open coded xfs_attr_rmtval_set without trans
> handling */
> -		if ((attr->xattri_flags & XFS_DAC_LEAF_ADDNAME_INIT) ==
> 0) {
> -			attr->xattri_flags |=
> XFS_DAC_LEAF_ADDNAME_INIT;
> -			if (args->rmtblkno > 0) {
> -				error =
> xfs_attr_rmtval_find_space(attr);
> +		if (args->rmtblkno > 0) {
> +			if (attr->xattri_blkcnt > 0) {
> +				error = xfs_attr_rmtval_set_blk(attr);
>  				if (error)
>  					return error;
> +				trace_xfs_attr_set_iter_return(
> +						attr-
> >xattri_dela_state,
> +						args->dp);
> +				return -EAGAIN;
>  			}
> -		}
>  
> -		/*
> -		 * Repeat allocating remote blocks for the attr value
> until
> -		 * blkcnt drops to zero.
> -		 */
> -		if (attr->xattri_blkcnt > 0) {
> -			error = xfs_attr_rmtval_set_blk(attr);
> +			error = xfs_attr_rmtval_set_value(args);
>  			if (error)
>  				return error;
> -			trace_xfs_attr_set_iter_return(attr-
> >xattri_dela_state,
> -						       args->dp);
> -			return -EAGAIN;
>  		}
>  
> -		error = xfs_attr_rmtval_set_value(args);
> -		if (error)
> -			return error;
> -
>  		/*
>  		 * If this is not a rename, clear the incomplete flag
> and we're
>  		 * done.
> @@ -547,15 +548,15 @@ xfs_attr_set_iter(
>  				return error;
>  		}
>  
> +		attr->xattri_dela_state = XFS_DAS_NODE_ALLOC_RMT;
>  		fallthrough;
> -	case XFS_DAS_ALLOC_NODE:
> +	case XFS_DAS_NODE_ALLOC_RMT:
>  		/*
>  		 * If there was an out-of-line value, allocate the
> blocks we
>  		 * identified for its storage and copy the value.  This
> is done
>  		 * after we create the attribute so that we don't
> overflow the
>  		 * maximum size of a transaction and/or hit a deadlock.
>  		 */
> -		attr->xattri_dela_state = XFS_DAS_ALLOC_NODE;
>  		if (args->rmtblkno > 0) {
>  			if (attr->xattri_blkcnt > 0) {
>  				error = xfs_attr_rmtval_set_blk(attr);
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index fc2a177f6994..184dca735cf3 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -451,11 +451,12 @@ enum xfs_delattr_state {
>  	XFS_DAS_RM_NAME,		/* Remove attr name */
>  	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree
> */
>  	XFS_DAS_FOUND_LBLK,		/* We found leaf blk for attr
> */
> +	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr
> */
> +	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE
> attr flag */
>  	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks
> */
>  	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
> -	XFS_DAS_ALLOC_NODE,		/* We are allocating node
> blocks */
>  	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE
> attr flag */
>  	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks
> */
>  	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
> @@ -471,11 +472,12 @@ enum xfs_delattr_state {
>  	{ XFS_DAS_RM_NAME,	"XFS_DAS_RM_NAME" }, \
>  	{ XFS_DAS_RM_SHRINK,	"XFS_DAS_RM_SHRINK" }, \
>  	{ XFS_DAS_FOUND_LBLK,	"XFS_DAS_FOUND_LBLK" }, \
> +	{ XFS_DAS_LEAF_ALLOC_RMT, "XFS_DAS_LEAF_ALLOC_RMT" }, \
>  	{ XFS_DAS_FOUND_NBLK,	"XFS_DAS_FOUND_NBLK" }, \
> +	{ XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" },  \
>  	{ XFS_DAS_FLIP_LFLAG,	"XFS_DAS_FLIP_LFLAG" }, \
>  	{ XFS_DAS_RM_LBLK,	"XFS_DAS_RM_LBLK" }, \
>  	{ XFS_DAS_RD_LEAF,	"XFS_DAS_RD_LEAF" }, \
> -	{ XFS_DAS_ALLOC_NODE,	"XFS_DAS_ALLOC_NODE" }, \
>  	{ XFS_DAS_FLIP_NFLAG,	"XFS_DAS_FLIP_NFLAG" }, \
>  	{ XFS_DAS_RM_NBLK,	"XFS_DAS_RM_NBLK" }, \
>  	{ XFS_DAS_CLR_FLAG,	"XFS_DAS_CLR_FLAG" }, \
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 9fc3fe334b5f..8739cc1e0561 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4106,11 +4106,12 @@ TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
>  TRACE_DEFINE_ENUM(XFS_DAS_FOUND_LBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_FOUND_NBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_FLIP_LFLAG);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
>  TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
> -TRACE_DEFINE_ENUM(XFS_DAS_ALLOC_NODE);
>  TRACE_DEFINE_ENUM(XFS_DAS_FLIP_NFLAG);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
>  TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);

[PATCH 06/16] xfs: consolidate leaf/node states in xfs_attr_set_iter

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

The operations performed from XFS_DAS_FOUND_LBLK through to
XFS_DAS_RM_LBLK are now identical to XFS_DAS_FOUND_NBLK through to
XFS_DAS_RM_NBLK. We can collapse these down into a single set of
code.

To do this, define the states that leaf and node run through as
separate sets of sequential states. Then as we move to the next
state, we can use increments rather than specific state assignments
to move through the states. This means the state progression is set
by the initial state that enters the series and we don't need to
duplicate the code anymore.

At the exit point of the series we need to select the correct leaf
or node state, but that can also be done by state increment rather
than assignment.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 127 ++++++---------------------------------
 fs/xfs/libxfs/xfs_attr.h |   9 ++-
 2 files changed, 27 insertions(+), 109 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index fed476bd048e..655e4388dfec 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -407,6 +407,7 @@ xfs_attr_set_iter(
 	struct xfs_mount		*mp = args->dp->i_mount;
 
 	/* State machine switch */
+next_state:
 	switch (attr->xattri_dela_state) {
 	case XFS_DAS_UNINIT:
 		ASSERT(0);
@@ -419,6 +420,7 @@ xfs_attr_set_iter(
 		return xfs_attr_node_addname(attr);
 
 	case XFS_DAS_FOUND_LBLK:
+	case XFS_DAS_FOUND_NBLK:
 		/*
 		 * Find space for remote blocks and fall into the allocation
 		 * state.
@@ -428,9 +430,10 @@ xfs_attr_set_iter(
 			if (error)
 				return error;
 		}
-		attr->xattri_dela_state = XFS_DAS_LEAF_ALLOC_RMT;
+		attr->xattri_dela_state++;
 		fallthrough;
 	case XFS_DAS_LEAF_ALLOC_RMT:
+	case XFS_DAS_NODE_ALLOC_RMT:
 
 		/*
 		 * If there was an out-of-line value, allocate the blocks we
@@ -479,16 +482,18 @@ xfs_attr_set_iter(
 				return error;
 			/*
 			 * Commit the flag value change and start the next trans
-			 * in series.
+			 * in series at FLIP_FLAG.
 			 */
-			attr->xattri_dela_state = XFS_DAS_FLIP_LFLAG;
+			attr->xattri_dela_state++;
 			trace_xfs_attr_set_iter_return(attr->xattri_dela_state,
 						       args->dp);
 			return -EAGAIN;
 		}
 
+		attr->xattri_dela_state++;
 		fallthrough;
 	case XFS_DAS_FLIP_LFLAG:
+	case XFS_DAS_FLIP_NFLAG:
 		/*
 		 * Dismantle the "old" attribute/value pair by removing a
 		 * "remote" value (if it exists).
@@ -498,10 +503,10 @@ xfs_attr_set_iter(
 		if (error)
 			return error;
 
+		attr->xattri_dela_state++;
 		fallthrough;
 	case XFS_DAS_RM_LBLK:
-		/* Set state in case xfs_attr_rmtval_remove returns -EAGAIN */
-		attr->xattri_dela_state = XFS_DAS_RM_LBLK;
+	case XFS_DAS_RM_NBLK:
 		if (args->rmtblkno) {
 			error = xfs_attr_rmtval_remove(attr);
 			if (error == -EAGAIN)
@@ -516,7 +521,16 @@ xfs_attr_set_iter(
 			return -EAGAIN;
 		}
 
-		fallthrough;
+		/*
+		 * This is the end of the shared leaf/node sequence. We need
+		 * to continue at the next state in the sequence, but we can't
+		 * easily just fall through. So we increment to the next state
+		 * and then jump back to switch statement to evaluate the next
+		 * state correctly.
+		 */
+		attr->xattri_dela_state++;
+		goto next_state;
+
 	case XFS_DAS_RD_LEAF:
 		/*
 		 * This is the last step for leaf format. Read the block with
@@ -537,106 +551,6 @@ xfs_attr_set_iter(
 
 		return error;
 
-	case XFS_DAS_FOUND_NBLK:
-		/*
-		 * Find space for remote blocks and fall into the allocation
-		 * state.
-		 */
-		if (args->rmtblkno > 0) {
-			error = xfs_attr_rmtval_find_space(attr);
-			if (error)
-				return error;
-		}
-
-		attr->xattri_dela_state = XFS_DAS_NODE_ALLOC_RMT;
-		fallthrough;
-	case XFS_DAS_NODE_ALLOC_RMT:
-		/*
-		 * If there was an out-of-line value, allocate the blocks we
-		 * identified for its storage and copy the value.  This is done
-		 * after we create the attribute so that we don't overflow the
-		 * maximum size of a transaction and/or hit a deadlock.
-		 */
-		if (args->rmtblkno > 0) {
-			if (attr->xattri_blkcnt > 0) {
-				error = xfs_attr_rmtval_set_blk(attr);
-				if (error)
-					return error;
-				trace_xfs_attr_set_iter_return(
-					attr->xattri_dela_state, args->dp);
-				return -EAGAIN;
-			}
-
-			error = xfs_attr_rmtval_set_value(args);
-			if (error)
-				return error;
-		}
-
-		/*
-		 * If this was not a rename, clear the incomplete flag and we're
-		 * done.
-		 */
-		if (!(args->op_flags & XFS_DA_OP_RENAME)) {
-			if (args->rmtblkno > 0)
-				error = xfs_attr3_leaf_clearflag(args);
-			goto out;
-		}
-
-		/*
-		 * If this is an atomic rename operation, we must "flip" the
-		 * incomplete flags on the "new" and "old" attribute/value pairs
-		 * so that one disappears and one appears atomically.  Then we
-		 * must remove the "old" attribute/value pair.
-		 *
-		 * In a separate transaction, set the incomplete flag on the
-		 * "old" attr and clear the incomplete flag on the "new" attr.
-		 */
-		if (!xfs_has_larp(mp)) {
-			error = xfs_attr3_leaf_flipflags(args);
-			if (error)
-				goto out;
-			/*
-			 * Commit the flag value change and start the next trans
-			 * in series
-			 */
-			attr->xattri_dela_state = XFS_DAS_FLIP_NFLAG;
-			trace_xfs_attr_set_iter_return(attr->xattri_dela_state,
-						       args->dp);
-			return -EAGAIN;
-		}
-
-		fallthrough;
-	case XFS_DAS_FLIP_NFLAG:
-		/*
-		 * Dismantle the "old" attribute/value pair by removing a
-		 * "remote" value (if it exists).
-		 */
-		xfs_attr_restore_rmt_blk(args);
-
-		error = xfs_attr_rmtval_invalidate(args);
-		if (error)
-			return error;
-
-		fallthrough;
-	case XFS_DAS_RM_NBLK:
-		/* Set state in case xfs_attr_rmtval_remove returns -EAGAIN */
-		attr->xattri_dela_state = XFS_DAS_RM_NBLK;
-		if (args->rmtblkno) {
-			error = xfs_attr_rmtval_remove(attr);
-			if (error == -EAGAIN)
-				trace_xfs_attr_set_iter_return(
-					attr->xattri_dela_state, args->dp);
-
-			if (error)
-				return error;
-
-			attr->xattri_dela_state = XFS_DAS_CLR_FLAG;
-			trace_xfs_attr_set_iter_return(attr->xattri_dela_state,
-						       args->dp);
-			return -EAGAIN;
-		}
-
-		fallthrough;
 	case XFS_DAS_CLR_FLAG:
 		/*
 		 * The last state for node format. Look up the old attr and
@@ -648,7 +562,6 @@ xfs_attr_set_iter(
 		ASSERT(0);
 		break;
 	}
-out:
 	return error;
 }
 
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index 184dca735cf3..0ad78f9279ac 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -450,16 +450,21 @@ enum xfs_delattr_state {
 	XFS_DAS_RMTBLK,			/* Removing remote blks */
 	XFS_DAS_RM_NAME,		/* Remove attr name */
 	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree */
+
+	/* Leaf state set sequence */
 	XFS_DAS_FOUND_LBLK,		/* We found leaf blk for attr */
 	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote blocks */
-	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr */
-	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE attr flag */
 	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks */
 	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
+
+	/* Node state set sequence, must match leaf state above */
+	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr */
+	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE attr flag */
 	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks */
 	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
+
 	XFS_DAS_DONE,			/* finished operation */
 };
 
-- 
2.35.1

Re: [PATCH 06/16] xfs: consolidate leaf/node states in xfs_attr_set_iter

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> The operations performed from XFS_DAS_FOUND_LBLK through to
> XFS_DAS_RM_LBLK are now identical to XFS_DAS_FOUND_NBLK through to
> XFS_DAS_RM_NBLK. We can collapse these down into a single set of
> code.
> 
> To do this, define the states that leaf and node run through as
> separate sets of sequential states. Then as we move to the next
> state, we can use increments rather than specific state assignments
> to move through the states. This means the state progression is set
> by the initial state that enters the series and we don't need to
> duplicate the code anymore.
> 
> At the exit point of the series we need to select the correct leaf
> or node state, but that can also be done by state increment rather
> than assignment.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

This is kind of loopy, but I can follow it.  As long as folks are ok
with it, I think it's fine, it does collapse down a lot of duplicate
code.
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

> ---
>  fs/xfs/libxfs/xfs_attr.c | 127 ++++++-------------------------------
> --
>  fs/xfs/libxfs/xfs_attr.h |   9 ++-
>  2 files changed, 27 insertions(+), 109 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index fed476bd048e..655e4388dfec 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -407,6 +407,7 @@ xfs_attr_set_iter(
>  	struct xfs_mount		*mp = args->dp->i_mount;
>  
>  	/* State machine switch */
> +next_state:
>  	switch (attr->xattri_dela_state) {
>  	case XFS_DAS_UNINIT:
>  		ASSERT(0);
> @@ -419,6 +420,7 @@ xfs_attr_set_iter(
>  		return xfs_attr_node_addname(attr);
>  
>  	case XFS_DAS_FOUND_LBLK:
> +	case XFS_DAS_FOUND_NBLK:
>  		/*
>  		 * Find space for remote blocks and fall into the
> allocation
>  		 * state.
> @@ -428,9 +430,10 @@ xfs_attr_set_iter(
>  			if (error)
>  				return error;
>  		}
> -		attr->xattri_dela_state = XFS_DAS_LEAF_ALLOC_RMT;
> +		attr->xattri_dela_state++;
>  		fallthrough;
>  	case XFS_DAS_LEAF_ALLOC_RMT:
> +	case XFS_DAS_NODE_ALLOC_RMT:
>  
>  		/*
>  		 * If there was an out-of-line value, allocate the
> blocks we
> @@ -479,16 +482,18 @@ xfs_attr_set_iter(
>  				return error;
>  			/*
>  			 * Commit the flag value change and start the
> next trans
> -			 * in series.
> +			 * in series at FLIP_FLAG.
>  			 */
> -			attr->xattri_dela_state = XFS_DAS_FLIP_LFLAG;
> +			attr->xattri_dela_state++;
>  			trace_xfs_attr_set_iter_return(attr-
> >xattri_dela_state,
>  						       args->dp);
>  			return -EAGAIN;
>  		}
>  
> +		attr->xattri_dela_state++;
>  		fallthrough;
>  	case XFS_DAS_FLIP_LFLAG:
> +	case XFS_DAS_FLIP_NFLAG:
>  		/*
>  		 * Dismantle the "old" attribute/value pair by removing
> a
>  		 * "remote" value (if it exists).
> @@ -498,10 +503,10 @@ xfs_attr_set_iter(
>  		if (error)
>  			return error;
>  
> +		attr->xattri_dela_state++;
>  		fallthrough;
>  	case XFS_DAS_RM_LBLK:
> -		/* Set state in case xfs_attr_rmtval_remove returns
> -EAGAIN */
> -		attr->xattri_dela_state = XFS_DAS_RM_LBLK;
> +	case XFS_DAS_RM_NBLK:
>  		if (args->rmtblkno) {
>  			error = xfs_attr_rmtval_remove(attr);
>  			if (error == -EAGAIN)
> @@ -516,7 +521,16 @@ xfs_attr_set_iter(
>  			return -EAGAIN;
>  		}
>  
> -		fallthrough;
> +		/*
> +		 * This is the end of the shared leaf/node sequence. We
> need
> +		 * to continue at the next state in the sequence, but
> we can't
> +		 * easily just fall through. So we increment to the
> next state
> +		 * and then jump back to switch statement to evaluate
> the next
> +		 * state correctly.
> +		 */
> +		attr->xattri_dela_state++;
> +		goto next_state;
> +
>  	case XFS_DAS_RD_LEAF:
>  		/*
>  		 * This is the last step for leaf format. Read the
> block with
> @@ -537,106 +551,6 @@ xfs_attr_set_iter(
>  
>  		return error;
>  
> -	case XFS_DAS_FOUND_NBLK:
> -		/*
> -		 * Find space for remote blocks and fall into the
> allocation
> -		 * state.
> -		 */
> -		if (args->rmtblkno > 0) {
> -			error = xfs_attr_rmtval_find_space(attr);
> -			if (error)
> -				return error;
> -		}
> -
> -		attr->xattri_dela_state = XFS_DAS_NODE_ALLOC_RMT;
> -		fallthrough;
> -	case XFS_DAS_NODE_ALLOC_RMT:
> -		/*
> -		 * If there was an out-of-line value, allocate the
> blocks we
> -		 * identified for its storage and copy the value.  This
> is done
> -		 * after we create the attribute so that we don't
> overflow the
> -		 * maximum size of a transaction and/or hit a deadlock.
> -		 */
> -		if (args->rmtblkno > 0) {
> -			if (attr->xattri_blkcnt > 0) {
> -				error = xfs_attr_rmtval_set_blk(attr);
> -				if (error)
> -					return error;
> -				trace_xfs_attr_set_iter_return(
> -					attr->xattri_dela_state, args-
> >dp);
> -				return -EAGAIN;
> -			}
> -
> -			error = xfs_attr_rmtval_set_value(args);
> -			if (error)
> -				return error;
> -		}
> -
> -		/*
> -		 * If this was not a rename, clear the incomplete flag
> and we're
> -		 * done.
> -		 */
> -		if (!(args->op_flags & XFS_DA_OP_RENAME)) {
> -			if (args->rmtblkno > 0)
> -				error = xfs_attr3_leaf_clearflag(args);
> -			goto out;
> -		}
> -
> -		/*
> -		 * If this is an atomic rename operation, we must
> "flip" the
> -		 * incomplete flags on the "new" and "old"
> attribute/value pairs
> -		 * so that one disappears and one appears
> atomically.  Then we
> -		 * must remove the "old" attribute/value pair.
> -		 *
> -		 * In a separate transaction, set the incomplete flag
> on the
> -		 * "old" attr and clear the incomplete flag on the
> "new" attr.
> -		 */
> -		if (!xfs_has_larp(mp)) {
> -			error = xfs_attr3_leaf_flipflags(args);
> -			if (error)
> -				goto out;
> -			/*
> -			 * Commit the flag value change and start the
> next trans
> -			 * in series
> -			 */
> -			attr->xattri_dela_state = XFS_DAS_FLIP_NFLAG;
> -			trace_xfs_attr_set_iter_return(attr-
> >xattri_dela_state,
> -						       args->dp);
> -			return -EAGAIN;
> -		}
> -
> -		fallthrough;
> -	case XFS_DAS_FLIP_NFLAG:
> -		/*
> -		 * Dismantle the "old" attribute/value pair by removing
> a
> -		 * "remote" value (if it exists).
> -		 */
> -		xfs_attr_restore_rmt_blk(args);
> -
> -		error = xfs_attr_rmtval_invalidate(args);
> -		if (error)
> -			return error;
> -
> -		fallthrough;
> -	case XFS_DAS_RM_NBLK:
> -		/* Set state in case xfs_attr_rmtval_remove returns
> -EAGAIN */
> -		attr->xattri_dela_state = XFS_DAS_RM_NBLK;
> -		if (args->rmtblkno) {
> -			error = xfs_attr_rmtval_remove(attr);
> -			if (error == -EAGAIN)
> -				trace_xfs_attr_set_iter_return(
> -					attr->xattri_dela_state, args-
> >dp);
> -
> -			if (error)
> -				return error;
> -
> -			attr->xattri_dela_state = XFS_DAS_CLR_FLAG;
> -			trace_xfs_attr_set_iter_return(attr-
> >xattri_dela_state,
> -						       args->dp);
> -			return -EAGAIN;
> -		}
> -
> -		fallthrough;
>  	case XFS_DAS_CLR_FLAG:
>  		/*
>  		 * The last state for node format. Look up the old attr
> and
> @@ -648,7 +562,6 @@ xfs_attr_set_iter(
>  		ASSERT(0);
>  		break;
>  	}
> -out:
>  	return error;
>  }
>  
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index 184dca735cf3..0ad78f9279ac 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -450,16 +450,21 @@ enum xfs_delattr_state {
>  	XFS_DAS_RMTBLK,			/* Removing remote blks */
>  	XFS_DAS_RM_NAME,		/* Remove attr name */
>  	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree
> */
> +
> +	/* Leaf state set sequence */
>  	XFS_DAS_FOUND_LBLK,		/* We found leaf blk for attr
> */
>  	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote
> blocks */
> -	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr
> */
> -	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE
> attr flag */
>  	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks
> */
>  	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
> +
> +	/* Node state set sequence, must match leaf state above */
> +	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr
> */
> +	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE
> attr flag */
>  	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks
> */
>  	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
> +
>  	XFS_DAS_DONE,			/* finished operation */
>  };
>  

[PATCH 07/16] xfs: split remote attr setting out from replace path

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

When we set a new xattr, we have three exit paths:

	1. nothign else to do
	2. allocate and set the remote xattr value
	3. perform the rest of a replace operation

Currently we push both 2 and 3 into the same state, regardless of
whether we just set a remote attribute or not. Once we've set the
remote xattr, we have two exit states:

	1. nothign else to do
	2. perform the rest of a replace operation

Hence we can split the remote xattr allocation and setting into
their own states and factor it out of xfs_attr_set_iter() to further
clean up the state machine and the implementation of the state
machine.


Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 113 +++++++++++++++++++++------------------
 fs/xfs/libxfs/xfs_attr.h |  14 +++--
 fs/xfs/xfs_trace.h       |   9 ++--
 3 files changed, 77 insertions(+), 59 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 655e4388dfec..4b9c107fe5de 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -347,9 +347,11 @@ xfs_attr_leaf_addname(
 	 * or perform more xattr manipulations. Otherwise there is nothing more
 	 * to do and we can return success.
 	 */
-	if (args->rmtblkno ||
-	    (args->op_flags & XFS_DA_OP_RENAME)) {
-		attr->xattri_dela_state = XFS_DAS_FOUND_LBLK;
+	if (args->rmtblkno) {
+		attr->xattri_dela_state = XFS_DAS_LEAF_SET_RMT;
+		error = -EAGAIN;
+	} else if (args->op_flags & XFS_DA_OP_RENAME) {
+		attr->xattri_dela_state = XFS_DAS_LEAF_REPLACE;
 		error = -EAGAIN;
 	} else {
 		attr->xattri_dela_state = XFS_DAS_DONE;
@@ -376,9 +378,11 @@ xfs_attr_node_addname(
 	if (error)
 		return error;
 
-	if (args->rmtblkno ||
-	    (args->op_flags & XFS_DA_OP_RENAME)) {
-		attr->xattri_dela_state = XFS_DAS_FOUND_NBLK;
+	if (args->rmtblkno) {
+		attr->xattri_dela_state = XFS_DAS_NODE_SET_RMT;
+		error = -EAGAIN;
+	} else if (args->op_flags & XFS_DA_OP_RENAME) {
+		attr->xattri_dela_state = XFS_DAS_NODE_REPLACE;
 		error = -EAGAIN;
 	} else {
 		attr->xattri_dela_state = XFS_DAS_DONE;
@@ -388,6 +392,40 @@ xfs_attr_node_addname(
 	return error;
 }
 
+static int
+xfs_attr_rmtval_alloc(
+	struct xfs_attr_item		*attr)
+{
+	struct xfs_da_args              *args = attr->xattri_da_args;
+	int				error = 0;
+
+	/*
+	 * If there was an out-of-line value, allocate the blocks we
+	 * identified for its storage and copy the value.  This is done
+	 * after we create the attribute so that we don't overflow the
+	 * maximum size of a transaction and/or hit a deadlock.
+	 */
+	if (attr->xattri_blkcnt > 0) {
+		error = xfs_attr_rmtval_set_blk(attr);
+		if (error)
+			return error;
+		error = -EAGAIN;
+		goto out;
+	}
+
+	error = xfs_attr_rmtval_set_value(args);
+	if (error)
+		return error;
+
+	/* If this is not a rename, clear the incomplete flag and we're done. */
+	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
+		error = xfs_attr3_leaf_clearflag(args);
+		attr->xattri_dela_state = XFS_DAS_DONE;
+	}
+out:
+	trace_xfs_attr_rmtval_alloc(attr->xattri_dela_state, args->dp);
+	return error;
+}
 
 /*
  * Set the attribute specified in @args.
@@ -419,54 +457,26 @@ xfs_attr_set_iter(
 	case XFS_DAS_NODE_ADD:
 		return xfs_attr_node_addname(attr);
 
-	case XFS_DAS_FOUND_LBLK:
-	case XFS_DAS_FOUND_NBLK:
-		/*
-		 * Find space for remote blocks and fall into the allocation
-		 * state.
-		 */
-		if (args->rmtblkno > 0) {
-			error = xfs_attr_rmtval_find_space(attr);
-			if (error)
-				return error;
-		}
+	case XFS_DAS_LEAF_SET_RMT:
+	case XFS_DAS_NODE_SET_RMT:
+		error = xfs_attr_rmtval_find_space(attr);
+		if (error)
+			return error;
 		attr->xattri_dela_state++;
 		fallthrough;
+
 	case XFS_DAS_LEAF_ALLOC_RMT:
 	case XFS_DAS_NODE_ALLOC_RMT:
-
-		/*
-		 * If there was an out-of-line value, allocate the blocks we
-		 * identified for its storage and copy the value.  This is done
-		 * after we create the attribute so that we don't overflow the
-		 * maximum size of a transaction and/or hit a deadlock.
-		 */
-		if (args->rmtblkno > 0) {
-			if (attr->xattri_blkcnt > 0) {
-				error = xfs_attr_rmtval_set_blk(attr);
-				if (error)
-					return error;
-				trace_xfs_attr_set_iter_return(
-						attr->xattri_dela_state,
-						args->dp);
-				return -EAGAIN;
-			}
-
-			error = xfs_attr_rmtval_set_value(args);
-			if (error)
-				return error;
-		}
-
-		/*
-		 * If this is not a rename, clear the incomplete flag and we're
-		 * done.
-		 */
-		if (!(args->op_flags & XFS_DA_OP_RENAME)) {
-			if (args->rmtblkno > 0)
-				error = xfs_attr3_leaf_clearflag(args);
+		error = xfs_attr_rmtval_alloc(attr);
+		if (error)
 			return error;
-		}
+		if (attr->xattri_dela_state == XFS_DAS_DONE)
+			break;
+		attr->xattri_dela_state++;
+		fallthrough;
 
+	case XFS_DAS_LEAF_REPLACE:
+	case XFS_DAS_NODE_REPLACE:
 		/*
 		 * If this is an atomic rename operation, we must "flip" the
 		 * incomplete flags on the "new" and "old" attribute/value pairs
@@ -484,10 +494,9 @@ xfs_attr_set_iter(
 			 * Commit the flag value change and start the next trans
 			 * in series at FLIP_FLAG.
 			 */
+			error = -EAGAIN;
 			attr->xattri_dela_state++;
-			trace_xfs_attr_set_iter_return(attr->xattri_dela_state,
-						       args->dp);
-			return -EAGAIN;
+			break;
 		}
 
 		attr->xattri_dela_state++;
@@ -562,6 +571,8 @@ xfs_attr_set_iter(
 		ASSERT(0);
 		break;
 	}
+
+	trace_xfs_attr_set_iter_return(attr->xattri_dela_state, args->dp);
 	return error;
 }
 
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index 0ad78f9279ac..1de6c06b7f19 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -452,15 +452,17 @@ enum xfs_delattr_state {
 	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree */
 
 	/* Leaf state set sequence */
-	XFS_DAS_FOUND_LBLK,		/* We found leaf blk for attr */
+	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a leaf */
 	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote blocks */
+	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a leaf */
 	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE attr flag */
 	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks */
 	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
 
 	/* Node state set sequence, must match leaf state above */
-	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr */
+	XFS_DAS_NODE_SET_RMT,		/* set a remote xattr from a node */
 	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote blocks */
+	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a node */
 	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE attr flag */
 	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks */
 	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
@@ -476,13 +478,15 @@ enum xfs_delattr_state {
 	{ XFS_DAS_RMTBLK,	"XFS_DAS_RMTBLK" }, \
 	{ XFS_DAS_RM_NAME,	"XFS_DAS_RM_NAME" }, \
 	{ XFS_DAS_RM_SHRINK,	"XFS_DAS_RM_SHRINK" }, \
-	{ XFS_DAS_FOUND_LBLK,	"XFS_DAS_FOUND_LBLK" }, \
+	{ XFS_DAS_LEAF_SET_RMT,	"XFS_DAS_LEAF_SET_RMT" }, \
 	{ XFS_DAS_LEAF_ALLOC_RMT, "XFS_DAS_LEAF_ALLOC_RMT" }, \
-	{ XFS_DAS_FOUND_NBLK,	"XFS_DAS_FOUND_NBLK" }, \
-	{ XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" },  \
+	{ XFS_DAS_LEAF_REPLACE,	"XFS_DAS_LEAF_REPLACE" }, \
 	{ XFS_DAS_FLIP_LFLAG,	"XFS_DAS_FLIP_LFLAG" }, \
 	{ XFS_DAS_RM_LBLK,	"XFS_DAS_RM_LBLK" }, \
 	{ XFS_DAS_RD_LEAF,	"XFS_DAS_RD_LEAF" }, \
+	{ XFS_DAS_NODE_SET_RMT,	"XFS_DAS_NODE_SET_RMT" }, \
+	{ XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" },  \
+	{ XFS_DAS_NODE_REPLACE,	"XFS_DAS_NODE_REPLACE" },  \
 	{ XFS_DAS_FLIP_NFLAG,	"XFS_DAS_FLIP_NFLAG" }, \
 	{ XFS_DAS_RM_NBLK,	"XFS_DAS_RM_NBLK" }, \
 	{ XFS_DAS_CLR_FLAG,	"XFS_DAS_CLR_FLAG" }, \
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 8739cc1e0561..cf99efc5ba5a 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -4105,13 +4105,15 @@ TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
 TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
-TRACE_DEFINE_ENUM(XFS_DAS_FOUND_LBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
-TRACE_DEFINE_ENUM(XFS_DAS_FOUND_NBLK);
-TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
+TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
 TRACE_DEFINE_ENUM(XFS_DAS_FLIP_LFLAG);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
 TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_SET_RMT);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_REPLACE);
 TRACE_DEFINE_ENUM(XFS_DAS_FLIP_NFLAG);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
 TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
@@ -4141,6 +4143,7 @@ DEFINE_DAS_STATE_EVENT(xfs_attr_set_iter_return);
 DEFINE_DAS_STATE_EVENT(xfs_attr_leaf_addname_return);
 DEFINE_DAS_STATE_EVENT(xfs_attr_node_addname_return);
 DEFINE_DAS_STATE_EVENT(xfs_attr_remove_iter_return);
+DEFINE_DAS_STATE_EVENT(xfs_attr_rmtval_alloc);
 DEFINE_DAS_STATE_EVENT(xfs_attr_rmtval_remove_return);
 
 TRACE_EVENT(xfs_force_shutdown,
-- 
2.35.1

Re: [PATCH 07/16] xfs: split remote attr setting out from replace path

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> When we set a new xattr, we have three exit paths:
> 
> 	1. nothign else to do
> 	2. allocate and set the remote xattr value
> 	3. perform the rest of a replace operation
> 
> Currently we push both 2 and 3 into the same state, regardless of
> whether we just set a remote attribute or not. Once we've set the
> remote xattr, we have two exit states:
> 
> 	1. nothign else to do
> 	2. perform the rest of a replace operation
> 
> Hence we can split the remote xattr allocation and setting into
> their own states and factor it out of xfs_attr_set_iter() to further
> clean up the state machine and the implementation of the state
> machine.
> 
> 
Looks like it should retain the same code flow.  I can follow it, but I
feel like I'm the only one reviewing this?  As long as folks are ok
with the new code flow, I'm fine with it.

Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 113 +++++++++++++++++++++--------------
> ----
>  fs/xfs/libxfs/xfs_attr.h |  14 +++--
>  fs/xfs/xfs_trace.h       |   9 ++--
>  3 files changed, 77 insertions(+), 59 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 655e4388dfec..4b9c107fe5de 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -347,9 +347,11 @@ xfs_attr_leaf_addname(
>  	 * or perform more xattr manipulations. Otherwise there is
> nothing more
>  	 * to do and we can return success.
>  	 */
> -	if (args->rmtblkno ||
> -	    (args->op_flags & XFS_DA_OP_RENAME)) {
> -		attr->xattri_dela_state = XFS_DAS_FOUND_LBLK;
> +	if (args->rmtblkno) {
> +		attr->xattri_dela_state = XFS_DAS_LEAF_SET_RMT;
> +		error = -EAGAIN;
> +	} else if (args->op_flags & XFS_DA_OP_RENAME) {
> +		attr->xattri_dela_state = XFS_DAS_LEAF_REPLACE;
>  		error = -EAGAIN;
>  	} else {
>  		attr->xattri_dela_state = XFS_DAS_DONE;
> @@ -376,9 +378,11 @@ xfs_attr_node_addname(
>  	if (error)
>  		return error;
>  
> -	if (args->rmtblkno ||
> -	    (args->op_flags & XFS_DA_OP_RENAME)) {
> -		attr->xattri_dela_state = XFS_DAS_FOUND_NBLK;
> +	if (args->rmtblkno) {
> +		attr->xattri_dela_state = XFS_DAS_NODE_SET_RMT;
> +		error = -EAGAIN;
> +	} else if (args->op_flags & XFS_DA_OP_RENAME) {
> +		attr->xattri_dela_state = XFS_DAS_NODE_REPLACE;
>  		error = -EAGAIN;
>  	} else {
>  		attr->xattri_dela_state = XFS_DAS_DONE;
> @@ -388,6 +392,40 @@ xfs_attr_node_addname(
>  	return error;
>  }
>  
> +static int
> +xfs_attr_rmtval_alloc(
> +	struct xfs_attr_item		*attr)
> +{
> +	struct xfs_da_args              *args = attr->xattri_da_args;
> +	int				error = 0;
> +
> +	/*
> +	 * If there was an out-of-line value, allocate the blocks we
> +	 * identified for its storage and copy the value.  This is done
> +	 * after we create the attribute so that we don't overflow the
> +	 * maximum size of a transaction and/or hit a deadlock.
> +	 */
> +	if (attr->xattri_blkcnt > 0) {
> +		error = xfs_attr_rmtval_set_blk(attr);
> +		if (error)
> +			return error;
> +		error = -EAGAIN;
> +		goto out;
> +	}
> +
> +	error = xfs_attr_rmtval_set_value(args);
> +	if (error)
> +		return error;
> +
> +	/* If this is not a rename, clear the incomplete flag and we're
> done. */
> +	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
> +		error = xfs_attr3_leaf_clearflag(args);
> +		attr->xattri_dela_state = XFS_DAS_DONE;
> +	}
> +out:
> +	trace_xfs_attr_rmtval_alloc(attr->xattri_dela_state, args->dp);
> +	return error;
> +}
>  
>  /*
>   * Set the attribute specified in @args.
> @@ -419,54 +457,26 @@ xfs_attr_set_iter(
>  	case XFS_DAS_NODE_ADD:
>  		return xfs_attr_node_addname(attr);
>  
> -	case XFS_DAS_FOUND_LBLK:
> -	case XFS_DAS_FOUND_NBLK:
> -		/*
> -		 * Find space for remote blocks and fall into the
> allocation
> -		 * state.
> -		 */
> -		if (args->rmtblkno > 0) {
> -			error = xfs_attr_rmtval_find_space(attr);
> -			if (error)
> -				return error;
> -		}
> +	case XFS_DAS_LEAF_SET_RMT:
> +	case XFS_DAS_NODE_SET_RMT:
> +		error = xfs_attr_rmtval_find_space(attr);
> +		if (error)
> +			return error;
>  		attr->xattri_dela_state++;
>  		fallthrough;
> +
>  	case XFS_DAS_LEAF_ALLOC_RMT:
>  	case XFS_DAS_NODE_ALLOC_RMT:
> -
> -		/*
> -		 * If there was an out-of-line value, allocate the
> blocks we
> -		 * identified for its storage and copy the value.  This
> is done
> -		 * after we create the attribute so that we don't
> overflow the
> -		 * maximum size of a transaction and/or hit a deadlock.
> -		 */
> -		if (args->rmtblkno > 0) {
> -			if (attr->xattri_blkcnt > 0) {
> -				error = xfs_attr_rmtval_set_blk(attr);
> -				if (error)
> -					return error;
> -				trace_xfs_attr_set_iter_return(
> -						attr-
> >xattri_dela_state,
> -						args->dp);
> -				return -EAGAIN;
> -			}
> -
> -			error = xfs_attr_rmtval_set_value(args);
> -			if (error)
> -				return error;
> -		}
> -
> -		/*
> -		 * If this is not a rename, clear the incomplete flag
> and we're
> -		 * done.
> -		 */
> -		if (!(args->op_flags & XFS_DA_OP_RENAME)) {
> -			if (args->rmtblkno > 0)
> -				error = xfs_attr3_leaf_clearflag(args);
> +		error = xfs_attr_rmtval_alloc(attr);
> +		if (error)
>  			return error;
> -		}
> +		if (attr->xattri_dela_state == XFS_DAS_DONE)
> +			break;
> +		attr->xattri_dela_state++;
> +		fallthrough;
>  
> +	case XFS_DAS_LEAF_REPLACE:
> +	case XFS_DAS_NODE_REPLACE:
>  		/*
>  		 * If this is an atomic rename operation, we must
> "flip" the
>  		 * incomplete flags on the "new" and "old"
> attribute/value pairs
> @@ -484,10 +494,9 @@ xfs_attr_set_iter(
>  			 * Commit the flag value change and start the
> next trans
>  			 * in series at FLIP_FLAG.
>  			 */
> +			error = -EAGAIN;
>  			attr->xattri_dela_state++;
> -			trace_xfs_attr_set_iter_return(attr-
> >xattri_dela_state,
> -						       args->dp);
> -			return -EAGAIN;
> +			break;
>  		}
>  
>  		attr->xattri_dela_state++;
> @@ -562,6 +571,8 @@ xfs_attr_set_iter(
>  		ASSERT(0);
>  		break;
>  	}
> +
> +	trace_xfs_attr_set_iter_return(attr->xattri_dela_state, args-
> >dp);
>  	return error;
>  }
>  
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index 0ad78f9279ac..1de6c06b7f19 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -452,15 +452,17 @@ enum xfs_delattr_state {
>  	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree
> */
>  
>  	/* Leaf state set sequence */
> -	XFS_DAS_FOUND_LBLK,		/* We found leaf blk for attr
> */
> +	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a
> leaf */
>  	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote
> blocks */
> +	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a
> leaf */
>  	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE
> attr flag */
>  	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks
> */
>  	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
>  
>  	/* Node state set sequence, must match leaf state above */
> -	XFS_DAS_FOUND_NBLK,		/* We found node blk for attr
> */
> +	XFS_DAS_NODE_SET_RMT,		/* set a remote xattr from a
> node */
>  	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote
> blocks */
> +	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a
> node */
>  	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE
> attr flag */
>  	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks
> */
>  	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
> @@ -476,13 +478,15 @@ enum xfs_delattr_state {
>  	{ XFS_DAS_RMTBLK,	"XFS_DAS_RMTBLK" }, \
>  	{ XFS_DAS_RM_NAME,	"XFS_DAS_RM_NAME" }, \
>  	{ XFS_DAS_RM_SHRINK,	"XFS_DAS_RM_SHRINK" }, \
> -	{ XFS_DAS_FOUND_LBLK,	"XFS_DAS_FOUND_LBLK" }, \
> +	{ XFS_DAS_LEAF_SET_RMT,	"XFS_DAS_LEAF_SET_RMT" }, \
>  	{ XFS_DAS_LEAF_ALLOC_RMT, "XFS_DAS_LEAF_ALLOC_RMT" }, \
> -	{ XFS_DAS_FOUND_NBLK,	"XFS_DAS_FOUND_NBLK" }, \
> -	{ XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" },  \
> +	{ XFS_DAS_LEAF_REPLACE,	"XFS_DAS_LEAF_REPLACE" }, \
>  	{ XFS_DAS_FLIP_LFLAG,	"XFS_DAS_FLIP_LFLAG" }, \
>  	{ XFS_DAS_RM_LBLK,	"XFS_DAS_RM_LBLK" }, \
>  	{ XFS_DAS_RD_LEAF,	"XFS_DAS_RD_LEAF" }, \
> +	{ XFS_DAS_NODE_SET_RMT,	"XFS_DAS_NODE_SET_RMT" }, \
> +	{ XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" },  \
> +	{ XFS_DAS_NODE_REPLACE,	"XFS_DAS_NODE_REPLACE" },  \
>  	{ XFS_DAS_FLIP_NFLAG,	"XFS_DAS_FLIP_NFLAG" }, \
>  	{ XFS_DAS_RM_NBLK,	"XFS_DAS_RM_NBLK" }, \
>  	{ XFS_DAS_CLR_FLAG,	"XFS_DAS_CLR_FLAG" }, \
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 8739cc1e0561..cf99efc5ba5a 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4105,13 +4105,15 @@ TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
>  TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
> -TRACE_DEFINE_ENUM(XFS_DAS_FOUND_LBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
> -TRACE_DEFINE_ENUM(XFS_DAS_FOUND_NBLK);
> -TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
>  TRACE_DEFINE_ENUM(XFS_DAS_FLIP_LFLAG);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
>  TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_SET_RMT);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_REPLACE);
>  TRACE_DEFINE_ENUM(XFS_DAS_FLIP_NFLAG);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
>  TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
> @@ -4141,6 +4143,7 @@
> DEFINE_DAS_STATE_EVENT(xfs_attr_set_iter_return);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_leaf_addname_return);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_node_addname_return);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_remove_iter_return);
> +DEFINE_DAS_STATE_EVENT(xfs_attr_rmtval_alloc);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_rmtval_remove_return);
>  
>  TRACE_EVENT(xfs_force_shutdown,

[PATCH 08/16] xfs: XFS_DAS_LEAF_REPLACE state only needed if !LARP

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

We can skip the REPLACE state when LARP is enabled, but that means
the XFS_DAS_FLIP_LFLAG state is now poorly named - it indicates
something that has been done rather than what the state is going to
do. Rename it to "REMOVE_OLD" to indicate that we are now going to
perform removal of the old attr.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 79 ++++++++++++++++++++++++++--------------
 fs/xfs/libxfs/xfs_attr.h | 44 +++++++++++-----------
 fs/xfs/xfs_trace.h       |  4 +-
 3 files changed, 75 insertions(+), 52 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 4b9c107fe5de..c72f98794bb3 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -309,6 +309,23 @@ xfs_attr_sf_addname(
 	return error;
 }
 
+/*
+ * When we bump the state to REPLACE, we may actually need to skip over the
+ * state. When LARP mode is enabled, we don't need to run the atomic flags flip,
+ * so we skip straight over the REPLACE state and go on to REMOVE_OLD.
+ */
+static void
+xfs_attr_dela_state_set_replace(
+	struct xfs_attr_item	*attr,
+	enum xfs_delattr_state	replace)
+{
+	struct xfs_da_args	*args = attr->xattri_da_args;
+
+	attr->xattri_dela_state = replace;
+	if (xfs_has_larp(args->dp->i_mount))
+		attr->xattri_dela_state++;
+}
+
 static int
 xfs_attr_leaf_addname(
 	struct xfs_attr_item	*attr)
@@ -351,7 +368,7 @@ xfs_attr_leaf_addname(
 		attr->xattri_dela_state = XFS_DAS_LEAF_SET_RMT;
 		error = -EAGAIN;
 	} else if (args->op_flags & XFS_DA_OP_RENAME) {
-		attr->xattri_dela_state = XFS_DAS_LEAF_REPLACE;
+		xfs_attr_dela_state_set_replace(attr, XFS_DAS_LEAF_REPLACE);
 		error = -EAGAIN;
 	} else {
 		attr->xattri_dela_state = XFS_DAS_DONE;
@@ -382,7 +399,7 @@ xfs_attr_node_addname(
 		attr->xattri_dela_state = XFS_DAS_NODE_SET_RMT;
 		error = -EAGAIN;
 	} else if (args->op_flags & XFS_DA_OP_RENAME) {
-		attr->xattri_dela_state = XFS_DAS_NODE_REPLACE;
+		xfs_attr_dela_state_set_replace(attr, XFS_DAS_NODE_REPLACE);
 		error = -EAGAIN;
 	} else {
 		attr->xattri_dela_state = XFS_DAS_DONE;
@@ -421,6 +438,13 @@ xfs_attr_rmtval_alloc(
 	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
 		error = xfs_attr3_leaf_clearflag(args);
 		attr->xattri_dela_state = XFS_DAS_DONE;
+	} else {
+		/*
+		 * We are running a REPLACE operation, so we need to bump the
+		 * state to the step in that operation.
+		 */
+		attr->xattri_dela_state++;
+		xfs_attr_dela_state_set_replace(attr, attr->xattri_dela_state);
 	}
 out:
 	trace_xfs_attr_rmtval_alloc(attr->xattri_dela_state, args->dp);
@@ -442,7 +466,6 @@ xfs_attr_set_iter(
 	struct xfs_inode		*dp = args->dp;
 	struct xfs_buf			*bp = NULL;
 	int				forkoff, error = 0;
-	struct xfs_mount		*mp = args->dp->i_mount;
 
 	/* State machine switch */
 next_state:
@@ -470,39 +493,39 @@ xfs_attr_set_iter(
 		error = xfs_attr_rmtval_alloc(attr);
 		if (error)
 			return error;
+		/*
+		 * If there is still more to allocate we need to roll the
+		 * transaction so we have a full transaction reservation for
+		 * the next allocation.
+		 */
+		if (attr->xattri_blkcnt > 0)
+			break;
 		if (attr->xattri_dela_state == XFS_DAS_DONE)
 			break;
-		attr->xattri_dela_state++;
-		fallthrough;
+
+		goto next_state;
 
 	case XFS_DAS_LEAF_REPLACE:
 	case XFS_DAS_NODE_REPLACE:
 		/*
-		 * If this is an atomic rename operation, we must "flip" the
-		 * incomplete flags on the "new" and "old" attribute/value pairs
-		 * so that one disappears and one appears atomically.  Then we
-		 * must remove the "old" attribute/value pair.
-		 *
-		 * In a separate transaction, set the incomplete flag on the
-		 * "old" attr and clear the incomplete flag on the "new" attr.
+		 * We must "flip" the incomplete flags on the "new" and "old"
+		 * attribute/value pairs so that one disappears and one appears
+		 * atomically.  Then we must remove the "old" attribute/value
+		 * pair.
 		 */
-		if (!xfs_has_larp(mp)) {
-			error = xfs_attr3_leaf_flipflags(args);
-			if (error)
-				return error;
-			/*
-			 * Commit the flag value change and start the next trans
-			 * in series at FLIP_FLAG.
-			 */
-			error = -EAGAIN;
-			attr->xattri_dela_state++;
-			break;
-		}
-
+		error = xfs_attr3_leaf_flipflags(args);
+		if (error)
+			return error;
+		/*
+		 * Commit the flag value change and start the next trans
+		 * in series at REMOVE_OLD.
+		 */
+		error = -EAGAIN;
 		attr->xattri_dela_state++;
-		fallthrough;
-	case XFS_DAS_FLIP_LFLAG:
-	case XFS_DAS_FLIP_NFLAG:
+		break;
+
+	case XFS_DAS_LEAF_REMOVE_OLD:
+	case XFS_DAS_NODE_REMOVE_OLD:
 		/*
 		 * Dismantle the "old" attribute/value pair by removing a
 		 * "remote" value (if it exists).
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index 1de6c06b7f19..a4ff0a2305d6 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -455,7 +455,7 @@ enum xfs_delattr_state {
 	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a leaf */
 	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a leaf */
-	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE attr flag */
+	XFS_DAS_LEAF_REMOVE_OLD,	/* Start removing old attr from leaf */
 	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks */
 	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
 
@@ -463,7 +463,7 @@ enum xfs_delattr_state {
 	XFS_DAS_NODE_SET_RMT,		/* set a remote xattr from a node */
 	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a node */
-	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE attr flag */
+	XFS_DAS_NODE_REMOVE_OLD,	/* Start removing old attr from node */
 	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks */
 	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
 
@@ -471,26 +471,26 @@ enum xfs_delattr_state {
 };
 
 #define XFS_DAS_STRINGS	\
-	{ XFS_DAS_UNINIT,	"XFS_DAS_UNINIT" }, \
-	{ XFS_DAS_SF_ADD,	"XFS_DAS_SF_ADD" }, \
-	{ XFS_DAS_LEAF_ADD,	"XFS_DAS_LEAF_ADD" }, \
-	{ XFS_DAS_NODE_ADD,	"XFS_DAS_NODE_ADD" }, \
-	{ XFS_DAS_RMTBLK,	"XFS_DAS_RMTBLK" }, \
-	{ XFS_DAS_RM_NAME,	"XFS_DAS_RM_NAME" }, \
-	{ XFS_DAS_RM_SHRINK,	"XFS_DAS_RM_SHRINK" }, \
-	{ XFS_DAS_LEAF_SET_RMT,	"XFS_DAS_LEAF_SET_RMT" }, \
-	{ XFS_DAS_LEAF_ALLOC_RMT, "XFS_DAS_LEAF_ALLOC_RMT" }, \
-	{ XFS_DAS_LEAF_REPLACE,	"XFS_DAS_LEAF_REPLACE" }, \
-	{ XFS_DAS_FLIP_LFLAG,	"XFS_DAS_FLIP_LFLAG" }, \
-	{ XFS_DAS_RM_LBLK,	"XFS_DAS_RM_LBLK" }, \
-	{ XFS_DAS_RD_LEAF,	"XFS_DAS_RD_LEAF" }, \
-	{ XFS_DAS_NODE_SET_RMT,	"XFS_DAS_NODE_SET_RMT" }, \
-	{ XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" },  \
-	{ XFS_DAS_NODE_REPLACE,	"XFS_DAS_NODE_REPLACE" },  \
-	{ XFS_DAS_FLIP_NFLAG,	"XFS_DAS_FLIP_NFLAG" }, \
-	{ XFS_DAS_RM_NBLK,	"XFS_DAS_RM_NBLK" }, \
-	{ XFS_DAS_CLR_FLAG,	"XFS_DAS_CLR_FLAG" }, \
-	{ XFS_DAS_DONE,		"XFS_DAS_DONE" }
+	{ XFS_DAS_UNINIT,		"XFS_DAS_UNINIT" }, \
+	{ XFS_DAS_SF_ADD,		"XFS_DAS_SF_ADD" }, \
+	{ XFS_DAS_LEAF_ADD,		"XFS_DAS_LEAF_ADD" }, \
+	{ XFS_DAS_NODE_ADD,		"XFS_DAS_NODE_ADD" }, \
+	{ XFS_DAS_RMTBLK,		"XFS_DAS_RMTBLK" }, \
+	{ XFS_DAS_RM_NAME,		"XFS_DAS_RM_NAME" }, \
+	{ XFS_DAS_RM_SHRINK,		"XFS_DAS_RM_SHRINK" }, \
+	{ XFS_DAS_LEAF_SET_RMT,		"XFS_DAS_LEAF_SET_RMT" }, \
+	{ XFS_DAS_LEAF_ALLOC_RMT,	"XFS_DAS_LEAF_ALLOC_RMT" }, \
+	{ XFS_DAS_LEAF_REPLACE,		"XFS_DAS_LEAF_REPLACE" }, \
+	{ XFS_DAS_LEAF_REMOVE_OLD,	"XFS_DAS_LEAF_REMOVE_OLD" }, \
+	{ XFS_DAS_RM_LBLK,		"XFS_DAS_RM_LBLK" }, \
+	{ XFS_DAS_RD_LEAF,		"XFS_DAS_RD_LEAF" }, \
+	{ XFS_DAS_NODE_SET_RMT,		"XFS_DAS_NODE_SET_RMT" }, \
+	{ XFS_DAS_NODE_ALLOC_RMT,	"XFS_DAS_NODE_ALLOC_RMT" },  \
+	{ XFS_DAS_NODE_REPLACE,		"XFS_DAS_NODE_REPLACE" },  \
+	{ XFS_DAS_NODE_REMOVE_OLD,	"XFS_DAS_NODE_REMOVE_OLD" }, \
+	{ XFS_DAS_RM_NBLK,		"XFS_DAS_RM_NBLK" }, \
+	{ XFS_DAS_CLR_FLAG,		"XFS_DAS_CLR_FLAG" }, \
+	{ XFS_DAS_DONE,			"XFS_DAS_DONE" }
 
 /*
  * Defines for xfs_attr_item.xattri_flags
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index cf99efc5ba5a..a4b99c7f8ef0 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -4108,13 +4108,13 @@ TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
-TRACE_DEFINE_ENUM(XFS_DAS_FLIP_LFLAG);
+TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_OLD);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
 TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_SET_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_REPLACE);
-TRACE_DEFINE_ENUM(XFS_DAS_FLIP_NFLAG);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_OLD);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
 TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
 
-- 
2.35.1

Re: [PATCH 08/16] xfs: XFS_DAS_LEAF_REPLACE state only needed if !LARP

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> We can skip the REPLACE state when LARP is enabled, but that means
> the XFS_DAS_FLIP_LFLAG state is now poorly named - it indicates
> something that has been done rather than what the state is going to
> do. Rename it to "REMOVE_OLD" to indicate that we are now going to
> perform removal of the old attr.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 79 ++++++++++++++++++++++++++----------
> ----
>  fs/xfs/libxfs/xfs_attr.h | 44 +++++++++++-----------
>  fs/xfs/xfs_trace.h       |  4 +-
>  3 files changed, 75 insertions(+), 52 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 4b9c107fe5de..c72f98794bb3 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -309,6 +309,23 @@ xfs_attr_sf_addname(
>  	return error;
>  }
>  
> +/*
> + * When we bump the state to REPLACE, we may actually need to skip
> over the
> + * state. When LARP mode is enabled, we don't need to run the atomic
> flags flip,
> + * so we skip straight over the REPLACE state and go on to
> REMOVE_OLD.
> + */
> +static void
> +xfs_attr_dela_state_set_replace(
> +	struct xfs_attr_item	*attr,
> +	enum xfs_delattr_state	replace)
> +{
> +	struct xfs_da_args	*args = attr->xattri_da_args;
> +
	ASSERT(replace == XFS_DAS_LEAF_REPLACE ||
	       replace == XFS_DAS_NODE_REPLACE)
?

> +	attr->xattri_dela_state = replace;
> +	if (xfs_has_larp(args->dp->i_mount))
> +		attr->xattri_dela_state++;
> +}
> +
>  static int
>  xfs_attr_leaf_addname(
>  	struct xfs_attr_item	*attr)
> @@ -351,7 +368,7 @@ xfs_attr_leaf_addname(
>  		attr->xattri_dela_state = XFS_DAS_LEAF_SET_RMT;
>  		error = -EAGAIN;
>  	} else if (args->op_flags & XFS_DA_OP_RENAME) {
> -		attr->xattri_dela_state = XFS_DAS_LEAF_REPLACE;
> +		xfs_attr_dela_state_set_replace(attr,
> XFS_DAS_LEAF_REPLACE);
>  		error = -EAGAIN;
>  	} else {
>  		attr->xattri_dela_state = XFS_DAS_DONE;
> @@ -382,7 +399,7 @@ xfs_attr_node_addname(
>  		attr->xattri_dela_state = XFS_DAS_NODE_SET_RMT;
>  		error = -EAGAIN;
>  	} else if (args->op_flags & XFS_DA_OP_RENAME) {
> -		attr->xattri_dela_state = XFS_DAS_NODE_REPLACE;
> +		xfs_attr_dela_state_set_replace(attr,
> XFS_DAS_NODE_REPLACE);
>  		error = -EAGAIN;
>  	} else {
>  		attr->xattri_dela_state = XFS_DAS_DONE;
> @@ -421,6 +438,13 @@ xfs_attr_rmtval_alloc(
>  	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
>  		error = xfs_attr3_leaf_clearflag(args);
>  		attr->xattri_dela_state = XFS_DAS_DONE;
> +	} else {
> +		/*
> +		 * We are running a REPLACE operation, so we need to
> bump the
> +		 * state to the step in that operation.
> +		 */
> +		attr->xattri_dela_state++;
> +		xfs_attr_dela_state_set_replace(attr, attr-
> >xattri_dela_state);
>  	}
>  out:
>  	trace_xfs_attr_rmtval_alloc(attr->xattri_dela_state, args->dp);
> @@ -442,7 +466,6 @@ xfs_attr_set_iter(
>  	struct xfs_inode		*dp = args->dp;
>  	struct xfs_buf			*bp = NULL;
>  	int				forkoff, error = 0;
> -	struct xfs_mount		*mp = args->dp->i_mount;
>  
>  	/* State machine switch */
>  next_state:
> @@ -470,39 +493,39 @@ xfs_attr_set_iter(
>  		error = xfs_attr_rmtval_alloc(attr);
>  		if (error)
>  			return error;
> +		/*
> +		 * If there is still more to allocate we need to roll
> the
> +		 * transaction so we have a full transaction
> reservation for
> +		 * the next allocation.
> +		 */
> +		if (attr->xattri_blkcnt > 0)
> +			break;
Hmm, if attr->xattri_blkcnt > 0, then xfs_attr_rmtval_alloc returned
-EAGAIN, and we would have bailed out by now, so I dont think this part
ever gets executed.  Though I guess it doesnt hurt anything either?
 Rest looks ok though.

Allison
>  		if (attr->xattri_dela_state == XFS_DAS_DONE)
>  			break;
> -		attr->xattri_dela_state++;
> -		fallthrough;
> +
> +		goto next_state;
>  
>  	case XFS_DAS_LEAF_REPLACE:
>  	case XFS_DAS_NODE_REPLACE:
>  		/*
> -		 * If this is an atomic rename operation, we must
> "flip" the
> -		 * incomplete flags on the "new" and "old"
> attribute/value pairs
> -		 * so that one disappears and one appears
> atomically.  Then we
> -		 * must remove the "old" attribute/value pair.
> -		 *
> -		 * In a separate transaction, set the incomplete flag
> on the
> -		 * "old" attr and clear the incomplete flag on the
> "new" attr.
> +		 * We must "flip" the incomplete flags on the "new" and
> "old"
> +		 * attribute/value pairs so that one disappears and one
> appears
> +		 * atomically.  Then we must remove the "old"
> attribute/value
> +		 * pair.
>  		 */
> -		if (!xfs_has_larp(mp)) {
> -			error = xfs_attr3_leaf_flipflags(args);
> -			if (error)
> -				return error;
> -			/*
> -			 * Commit the flag value change and start the
> next trans
> -			 * in series at FLIP_FLAG.
> -			 */
> -			error = -EAGAIN;
> -			attr->xattri_dela_state++;
> -			break;
> -		}
> -
> +		error = xfs_attr3_leaf_flipflags(args);
> +		if (error)
> +			return error;
> +		/*
> +		 * Commit the flag value change and start the next
> trans
> +		 * in series at REMOVE_OLD.
> +		 */
> +		error = -EAGAIN;
>  		attr->xattri_dela_state++;
> -		fallthrough;
> -	case XFS_DAS_FLIP_LFLAG:
> -	case XFS_DAS_FLIP_NFLAG:
> +		break;
> +
> +	case XFS_DAS_LEAF_REMOVE_OLD:
> +	case XFS_DAS_NODE_REMOVE_OLD:
>  		/*
>  		 * Dismantle the "old" attribute/value pair by removing
> a
>  		 * "remote" value (if it exists).
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index 1de6c06b7f19..a4ff0a2305d6 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -455,7 +455,7 @@ enum xfs_delattr_state {
>  	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a
> leaf */
>  	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a
> leaf */
> -	XFS_DAS_FLIP_LFLAG,		/* Flipped leaf INCOMPLETE
> attr flag */
> +	XFS_DAS_LEAF_REMOVE_OLD,	/* Start removing old attr from leaf
> */
>  	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks
> */
>  	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
>  
> @@ -463,7 +463,7 @@ enum xfs_delattr_state {
>  	XFS_DAS_NODE_SET_RMT,		/* set a remote xattr from a
> node */
>  	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a
> node */
> -	XFS_DAS_FLIP_NFLAG,		/* Flipped node INCOMPLETE
> attr flag */
> +	XFS_DAS_NODE_REMOVE_OLD,	/* Start removing old attr from node
> */
>  	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks
> */
>  	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
>  
> @@ -471,26 +471,26 @@ enum xfs_delattr_state {
>  };
>  
>  #define XFS_DAS_STRINGS	\
> -	{ XFS_DAS_UNINIT,	"XFS_DAS_UNINIT" }, \
> -	{ XFS_DAS_SF_ADD,	"XFS_DAS_SF_ADD" }, \
> -	{ XFS_DAS_LEAF_ADD,	"XFS_DAS_LEAF_ADD" }, \
> -	{ XFS_DAS_NODE_ADD,	"XFS_DAS_NODE_ADD" }, \
> -	{ XFS_DAS_RMTBLK,	"XFS_DAS_RMTBLK" }, \
> -	{ XFS_DAS_RM_NAME,	"XFS_DAS_RM_NAME" }, \
> -	{ XFS_DAS_RM_SHRINK,	"XFS_DAS_RM_SHRINK" }, \
> -	{ XFS_DAS_LEAF_SET_RMT,	"XFS_DAS_LEAF_SET_RMT" }, \
> -	{ XFS_DAS_LEAF_ALLOC_RMT, "XFS_DAS_LEAF_ALLOC_RMT" }, \
> -	{ XFS_DAS_LEAF_REPLACE,	"XFS_DAS_LEAF_REPLACE" }, \
> -	{ XFS_DAS_FLIP_LFLAG,	"XFS_DAS_FLIP_LFLAG" }, \
> -	{ XFS_DAS_RM_LBLK,	"XFS_DAS_RM_LBLK" }, \
> -	{ XFS_DAS_RD_LEAF,	"XFS_DAS_RD_LEAF" }, \
> -	{ XFS_DAS_NODE_SET_RMT,	"XFS_DAS_NODE_SET_RMT" }, \
> -	{ XFS_DAS_NODE_ALLOC_RMT, "XFS_DAS_NODE_ALLOC_RMT" },  \
> -	{ XFS_DAS_NODE_REPLACE,	"XFS_DAS_NODE_REPLACE" },  \
> -	{ XFS_DAS_FLIP_NFLAG,	"XFS_DAS_FLIP_NFLAG" }, \
> -	{ XFS_DAS_RM_NBLK,	"XFS_DAS_RM_NBLK" }, \
> -	{ XFS_DAS_CLR_FLAG,	"XFS_DAS_CLR_FLAG" }, \
> -	{ XFS_DAS_DONE,		"XFS_DAS_DONE" }
> +	{ XFS_DAS_UNINIT,		"XFS_DAS_UNINIT" }, \
> +	{ XFS_DAS_SF_ADD,		"XFS_DAS_SF_ADD" }, \
> +	{ XFS_DAS_LEAF_ADD,		"XFS_DAS_LEAF_ADD" }, \
> +	{ XFS_DAS_NODE_ADD,		"XFS_DAS_NODE_ADD" }, \
> +	{ XFS_DAS_RMTBLK,		"XFS_DAS_RMTBLK" }, \
> +	{ XFS_DAS_RM_NAME,		"XFS_DAS_RM_NAME" }, \
> +	{ XFS_DAS_RM_SHRINK,		"XFS_DAS_RM_SHRINK" }, \
> +	{ XFS_DAS_LEAF_SET_RMT,		"XFS_DAS_LEAF_SET_RMT" }, \
> +	{ XFS_DAS_LEAF_ALLOC_RMT,	"XFS_DAS_LEAF_ALLOC_RMT" }, \
> +	{ XFS_DAS_LEAF_REPLACE,		"XFS_DAS_LEAF_REPLACE" }, \
> +	{ XFS_DAS_LEAF_REMOVE_OLD,	"XFS_DAS_LEAF_REMOVE_OLD" },
> \
> +	{ XFS_DAS_RM_LBLK,		"XFS_DAS_RM_LBLK" }, \
> +	{ XFS_DAS_RD_LEAF,		"XFS_DAS_RD_LEAF" }, \
> +	{ XFS_DAS_NODE_SET_RMT,		"XFS_DAS_NODE_SET_RMT" }, \
> +	{ XFS_DAS_NODE_ALLOC_RMT,	"XFS_DAS_NODE_ALLOC_RMT" },  \
> +	{ XFS_DAS_NODE_REPLACE,		"XFS_DAS_NODE_REPLACE" },  \
> +	{ XFS_DAS_NODE_REMOVE_OLD,	"XFS_DAS_NODE_REMOVE_OLD" },
> \
> +	{ XFS_DAS_RM_NBLK,		"XFS_DAS_RM_NBLK" }, \
> +	{ XFS_DAS_CLR_FLAG,		"XFS_DAS_CLR_FLAG" }, \
> +	{ XFS_DAS_DONE,			"XFS_DAS_DONE" }
>  
>  /*
>   * Defines for xfs_attr_item.xattri_flags
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index cf99efc5ba5a..a4b99c7f8ef0 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4108,13 +4108,13 @@ TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
> -TRACE_DEFINE_ENUM(XFS_DAS_FLIP_LFLAG);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_OLD);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
>  TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_SET_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REPLACE);
> -TRACE_DEFINE_ENUM(XFS_DAS_FLIP_NFLAG);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_OLD);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
>  TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
>  

[PATCH 09/16] xfs: remote xattr removal in xfs_attr_set_iter() is conditional

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

We may not have a remote value for the old xattr we have to remove,
so skip over the remote value removal states and go straight to
the xattr name removal in the leaf/node block.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 59 ++++++++++++++++++++--------------------
 fs/xfs/libxfs/xfs_attr.h |  8 +++---
 fs/xfs/xfs_trace.h       |  4 +--
 3 files changed, 36 insertions(+), 35 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index c72f98794bb3..8762d3a0605a 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -510,15 +510,14 @@ xfs_attr_set_iter(
 		/*
 		 * We must "flip" the incomplete flags on the "new" and "old"
 		 * attribute/value pairs so that one disappears and one appears
-		 * atomically.  Then we must remove the "old" attribute/value
-		 * pair.
+		 * atomically.
 		 */
 		error = xfs_attr3_leaf_flipflags(args);
 		if (error)
 			return error;
 		/*
-		 * Commit the flag value change and start the next trans
-		 * in series at REMOVE_OLD.
+		 * We must commit the flag value change now to make it atomic
+		 * and then we can start the next trans in series at REMOVE_OLD.
 		 */
 		error = -EAGAIN;
 		attr->xattri_dela_state++;
@@ -527,41 +526,43 @@ xfs_attr_set_iter(
 	case XFS_DAS_LEAF_REMOVE_OLD:
 	case XFS_DAS_NODE_REMOVE_OLD:
 		/*
-		 * Dismantle the "old" attribute/value pair by removing a
-		 * "remote" value (if it exists).
+		 * If we have a remote attr, start the process of removing it
+		 * by invalidating any cached buffers.
+		 *
+		 * If we don't have a remote attr, we skip the remote block
+		 * removal state altogether with a second state increment.
 		 */
 		xfs_attr_restore_rmt_blk(args);
-		error = xfs_attr_rmtval_invalidate(args);
-		if (error)
-			return error;
-
-		attr->xattri_dela_state++;
-		fallthrough;
-	case XFS_DAS_RM_LBLK:
-	case XFS_DAS_RM_NBLK:
 		if (args->rmtblkno) {
-			error = xfs_attr_rmtval_remove(attr);
-			if (error == -EAGAIN)
-				trace_xfs_attr_set_iter_return(
-					attr->xattri_dela_state, args->dp);
+			error = xfs_attr_rmtval_invalidate(args);
 			if (error)
 				return error;
-
-			attr->xattri_dela_state = XFS_DAS_RD_LEAF;
-			trace_xfs_attr_set_iter_return(attr->xattri_dela_state,
-						       args->dp);
-			return -EAGAIN;
+		} else {
+			attr->xattri_dela_state++;
 		}
 
+		attr->xattri_dela_state++;
+		goto next_state;
+
+	case XFS_DAS_LEAF_REMOVE_RMT:
+	case XFS_DAS_NODE_REMOVE_RMT:
+		error = xfs_attr_rmtval_remove(attr);
+		if (error == -EAGAIN)
+			break;
+		if (error)
+			return error;
+
 		/*
-		 * This is the end of the shared leaf/node sequence. We need
-		 * to continue at the next state in the sequence, but we can't
-		 * easily just fall through. So we increment to the next state
-		 * and then jump back to switch statement to evaluate the next
-		 * state correctly.
+		 * We've finished removing the remote attr blocks, so commit the
+		 * transaction and move on to removing the attr name from the
+		 * leaf/node block. Removing the attr might require a full
+		 * transaction reservation for btree block freeing, so we
+		 * can't do that in the same transaction where we removed the
+		 * remote attr blocks.
 		 */
+		error = -EAGAIN;
 		attr->xattri_dela_state++;
-		goto next_state;
+		break;
 
 	case XFS_DAS_RD_LEAF:
 		/*
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index a4ff0a2305d6..18e157bf19cb 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -456,7 +456,7 @@ enum xfs_delattr_state {
 	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a leaf */
 	XFS_DAS_LEAF_REMOVE_OLD,	/* Start removing old attr from leaf */
-	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks */
+	XFS_DAS_LEAF_REMOVE_RMT,	/* A rename is removing remote blocks */
 	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
 
 	/* Node state set sequence, must match leaf state above */
@@ -464,7 +464,7 @@ enum xfs_delattr_state {
 	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a node */
 	XFS_DAS_NODE_REMOVE_OLD,	/* Start removing old attr from node */
-	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks */
+	XFS_DAS_NODE_REMOVE_RMT,	/* A rename is removing remote blocks */
 	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
 
 	XFS_DAS_DONE,			/* finished operation */
@@ -482,13 +482,13 @@ enum xfs_delattr_state {
 	{ XFS_DAS_LEAF_ALLOC_RMT,	"XFS_DAS_LEAF_ALLOC_RMT" }, \
 	{ XFS_DAS_LEAF_REPLACE,		"XFS_DAS_LEAF_REPLACE" }, \
 	{ XFS_DAS_LEAF_REMOVE_OLD,	"XFS_DAS_LEAF_REMOVE_OLD" }, \
-	{ XFS_DAS_RM_LBLK,		"XFS_DAS_RM_LBLK" }, \
+	{ XFS_DAS_LEAF_REMOVE_RMT,	"XFS_DAS_LEAF_REMOVE_RMT" }, \
 	{ XFS_DAS_RD_LEAF,		"XFS_DAS_RD_LEAF" }, \
 	{ XFS_DAS_NODE_SET_RMT,		"XFS_DAS_NODE_SET_RMT" }, \
 	{ XFS_DAS_NODE_ALLOC_RMT,	"XFS_DAS_NODE_ALLOC_RMT" },  \
 	{ XFS_DAS_NODE_REPLACE,		"XFS_DAS_NODE_REPLACE" },  \
 	{ XFS_DAS_NODE_REMOVE_OLD,	"XFS_DAS_NODE_REMOVE_OLD" }, \
-	{ XFS_DAS_RM_NBLK,		"XFS_DAS_RM_NBLK" }, \
+	{ XFS_DAS_NODE_REMOVE_RMT,	"XFS_DAS_NODE_REMOVE_RMT" }, \
 	{ XFS_DAS_CLR_FLAG,		"XFS_DAS_CLR_FLAG" }, \
 	{ XFS_DAS_DONE,			"XFS_DAS_DONE" }
 
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index a4b99c7f8ef0..91852b9721e4 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -4109,13 +4109,13 @@ TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_OLD);
-TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_SET_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_REPLACE);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_OLD);
-TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
 
 DECLARE_EVENT_CLASS(xfs_das_state_class,
-- 
2.35.1

Re: [PATCH 09/16] xfs: remote xattr removal in xfs_attr_set_iter() is conditional

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> We may not have a remote value for the old xattr we have to remove,
> so skip over the remote value removal states and go straight to
> the xattr name removal in the leaf/node block.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Ok, I can follow it.  I may try and think of a new way to try and
illustrate it though as it is not nearly as linear as it used to be,
but I don't think that's a bad thing.  

Reviewed-by: Allison Henderson<allison.henderson@oracle.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 59 ++++++++++++++++++++----------------
> ----
>  fs/xfs/libxfs/xfs_attr.h |  8 +++---
>  fs/xfs/xfs_trace.h       |  4 +--
>  3 files changed, 36 insertions(+), 35 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index c72f98794bb3..8762d3a0605a 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -510,15 +510,14 @@ xfs_attr_set_iter(
>  		/*
>  		 * We must "flip" the incomplete flags on the "new" and
> "old"
>  		 * attribute/value pairs so that one disappears and one
> appears
> -		 * atomically.  Then we must remove the "old"
> attribute/value
> -		 * pair.
> +		 * atomically.
>  		 */
>  		error = xfs_attr3_leaf_flipflags(args);
>  		if (error)
>  			return error;
>  		/*
> -		 * Commit the flag value change and start the next
> trans
> -		 * in series at REMOVE_OLD.
> +		 * We must commit the flag value change now to make it
> atomic
> +		 * and then we can start the next trans in series at
> REMOVE_OLD.
>  		 */
>  		error = -EAGAIN;
>  		attr->xattri_dela_state++;
> @@ -527,41 +526,43 @@ xfs_attr_set_iter(
>  	case XFS_DAS_LEAF_REMOVE_OLD:
>  	case XFS_DAS_NODE_REMOVE_OLD:
>  		/*
> -		 * Dismantle the "old" attribute/value pair by removing
> a
> -		 * "remote" value (if it exists).
> +		 * If we have a remote attr, start the process of
> removing it
> +		 * by invalidating any cached buffers.
> +		 *
> +		 * If we don't have a remote attr, we skip the remote
> block
> +		 * removal state altogether with a second state
> increment.
>  		 */
>  		xfs_attr_restore_rmt_blk(args);
> -		error = xfs_attr_rmtval_invalidate(args);
> -		if (error)
> -			return error;
> -
> -		attr->xattri_dela_state++;
> -		fallthrough;
> -	case XFS_DAS_RM_LBLK:
> -	case XFS_DAS_RM_NBLK:
>  		if (args->rmtblkno) {
> -			error = xfs_attr_rmtval_remove(attr);
> -			if (error == -EAGAIN)
> -				trace_xfs_attr_set_iter_return(
> -					attr->xattri_dela_state, args-
> >dp);
> +			error = xfs_attr_rmtval_invalidate(args);
>  			if (error)
>  				return error;
> -
> -			attr->xattri_dela_state = XFS_DAS_RD_LEAF;
> -			trace_xfs_attr_set_iter_return(attr-
> >xattri_dela_state,
> -						       args->dp);
> -			return -EAGAIN;
> +		} else {
> +			attr->xattri_dela_state++;
>  		}
>  
> +		attr->xattri_dela_state++;
> +		goto next_state;
> +
> +	case XFS_DAS_LEAF_REMOVE_RMT:
> +	case XFS_DAS_NODE_REMOVE_RMT:
> +		error = xfs_attr_rmtval_remove(attr);
> +		if (error == -EAGAIN)
> +			break;
> +		if (error)
> +			return error;
> +
>  		/*
> -		 * This is the end of the shared leaf/node sequence. We
> need
> -		 * to continue at the next state in the sequence, but
> we can't
> -		 * easily just fall through. So we increment to the
> next state
> -		 * and then jump back to switch statement to evaluate
> the next
> -		 * state correctly.
> +		 * We've finished removing the remote attr blocks, so
> commit the
> +		 * transaction and move on to removing the attr name
> from the
> +		 * leaf/node block. Removing the attr might require a
> full
> +		 * transaction reservation for btree block freeing, so
> we
> +		 * can't do that in the same transaction where we
> removed the
> +		 * remote attr blocks.
>  		 */
> +		error = -EAGAIN;
>  		attr->xattri_dela_state++;
> -		goto next_state;
> +		break;
>  
>  	case XFS_DAS_RD_LEAF:
>  		/*
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index a4ff0a2305d6..18e157bf19cb 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -456,7 +456,7 @@ enum xfs_delattr_state {
>  	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a
> leaf */
>  	XFS_DAS_LEAF_REMOVE_OLD,	/* Start removing old attr from leaf
> */
> -	XFS_DAS_RM_LBLK,		/* A rename is removing leaf blocks
> */
> +	XFS_DAS_LEAF_REMOVE_RMT,	/* A rename is removing remote blocks
> */
>  	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
>  
>  	/* Node state set sequence, must match leaf state above */
> @@ -464,7 +464,7 @@ enum xfs_delattr_state {
>  	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a
> node */
>  	XFS_DAS_NODE_REMOVE_OLD,	/* Start removing old attr from node
> */
> -	XFS_DAS_RM_NBLK,		/* A rename is removing node blocks
> */
> +	XFS_DAS_NODE_REMOVE_RMT,	/* A rename is removing remote blocks
> */
>  	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
>  
>  	XFS_DAS_DONE,			/* finished operation */
> @@ -482,13 +482,13 @@ enum xfs_delattr_state {
>  	{ XFS_DAS_LEAF_ALLOC_RMT,	"XFS_DAS_LEAF_ALLOC_RMT" }, \
>  	{ XFS_DAS_LEAF_REPLACE,		"XFS_DAS_LEAF_REPLACE" }, \
>  	{ XFS_DAS_LEAF_REMOVE_OLD,	"XFS_DAS_LEAF_REMOVE_OLD" },
> \
> -	{ XFS_DAS_RM_LBLK,		"XFS_DAS_RM_LBLK" }, \
> +	{ XFS_DAS_LEAF_REMOVE_RMT,	"XFS_DAS_LEAF_REMOVE_RMT" },
> \
>  	{ XFS_DAS_RD_LEAF,		"XFS_DAS_RD_LEAF" }, \
>  	{ XFS_DAS_NODE_SET_RMT,		"XFS_DAS_NODE_SET_RMT" }, \
>  	{ XFS_DAS_NODE_ALLOC_RMT,	"XFS_DAS_NODE_ALLOC_RMT" },  \
>  	{ XFS_DAS_NODE_REPLACE,		"XFS_DAS_NODE_REPLACE" },  \
>  	{ XFS_DAS_NODE_REMOVE_OLD,	"XFS_DAS_NODE_REMOVE_OLD" },
> \
> -	{ XFS_DAS_RM_NBLK,		"XFS_DAS_RM_NBLK" }, \
> +	{ XFS_DAS_NODE_REMOVE_RMT,	"XFS_DAS_NODE_REMOVE_RMT" },
> \
>  	{ XFS_DAS_CLR_FLAG,		"XFS_DAS_CLR_FLAG" }, \
>  	{ XFS_DAS_DONE,			"XFS_DAS_DONE" }
>  
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index a4b99c7f8ef0..91852b9721e4 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4109,13 +4109,13 @@ TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_OLD);
> -TRACE_DEFINE_ENUM(XFS_DAS_RM_LBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_SET_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REPLACE);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_OLD);
> -TRACE_DEFINE_ENUM(XFS_DAS_RM_NBLK);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
>  
>  DECLARE_EVENT_CLASS(xfs_das_state_class,

[PATCH 10/16] xfs: clean up final attr removal in xfs_attr_set_iter

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

Clean up the final leaf/node states in xfs_attr_set_iter() to
further simplify the highe level state machine and to set the
completion state correctly.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 72 +++++++++++++++++++++++-----------------
 fs/xfs/libxfs/xfs_attr.h | 12 +++----
 fs/xfs/xfs_trace.h       |  5 +--
 3 files changed, 50 insertions(+), 39 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 8762d3a0605a..9dc08d59e4a6 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -61,7 +61,7 @@ STATIC int xfs_attr_node_get(xfs_da_args_t *args);
 STATIC void xfs_attr_restore_rmt_blk(struct xfs_da_args *args);
 static int xfs_attr_node_try_addname(struct xfs_attr_item *attr);
 STATIC int xfs_attr_node_addname_find_attr(struct xfs_attr_item *attr);
-STATIC int xfs_attr_node_addname_clear_incomplete(struct xfs_attr_item *attr);
+STATIC int xfs_attr_node_remove_attr(struct xfs_attr_item *attr);
 STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
 				 struct xfs_da_state **state);
 STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
@@ -451,6 +451,36 @@ xfs_attr_rmtval_alloc(
 	return error;
 }
 
+/*
+ * Remove the original attr we have just replaced. This is dependent on the
+ * original lookup and insert placing the old attr in args->blkno/args->index
+ * and the new attr in args->blkno2/args->index2.
+ */
+static int
+xfs_attr_leaf_remove_attr(
+	struct xfs_attr_item		*attr)
+{
+	struct xfs_da_args              *args = attr->xattri_da_args;
+	struct xfs_inode		*dp = args->dp;
+	struct xfs_buf			*bp = NULL;
+	int				forkoff;
+	int				error;
+
+	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno,
+				   &bp);
+	if (error)
+		return error;
+
+	xfs_attr3_leaf_remove(bp, args);
+
+	forkoff = xfs_attr_shortform_allfit(bp, dp);
+	if (forkoff)
+		error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
+		/* bp is gone due to xfs_da_shrink_inode */
+
+	return error;
+}
+
 /*
  * Set the attribute specified in @args.
  * This routine is meant to function as a delayed operation, and may return
@@ -463,9 +493,7 @@ xfs_attr_set_iter(
 	struct xfs_attr_item		*attr)
 {
 	struct xfs_da_args              *args = attr->xattri_da_args;
-	struct xfs_inode		*dp = args->dp;
-	struct xfs_buf			*bp = NULL;
-	int				forkoff, error = 0;
+	int				error = 0;
 
 	/* State machine switch */
 next_state:
@@ -564,32 +592,14 @@ xfs_attr_set_iter(
 		attr->xattri_dela_state++;
 		break;
 
-	case XFS_DAS_RD_LEAF:
-		/*
-		 * This is the last step for leaf format. Read the block with
-		 * the old attr, remove the old attr, check for shortform
-		 * conversion and return.
-		 */
-		error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno,
-					   &bp);
-		if (error)
-			return error;
-
-		xfs_attr3_leaf_remove(bp, args);
-
-		forkoff = xfs_attr_shortform_allfit(bp, dp);
-		if (forkoff)
-			error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
-			/* bp is gone due to xfs_da_shrink_inode */
-
-		return error;
+	case XFS_DAS_LEAF_REMOVE_ATTR:
+		error = xfs_attr_leaf_remove_attr(attr);
+		attr->xattri_dela_state = XFS_DAS_DONE;
+		break;
 
-	case XFS_DAS_CLR_FLAG:
-		/*
-		 * The last state for node format. Look up the old attr and
-		 * remove it.
-		 */
-		error = xfs_attr_node_addname_clear_incomplete(attr);
+	case XFS_DAS_NODE_REMOVE_ATTR:
+		error = xfs_attr_node_remove_attr(attr);
+		attr->xattri_dela_state = XFS_DAS_DONE;
 		break;
 	default:
 		ASSERT(0);
@@ -1262,8 +1272,8 @@ xfs_attr_node_try_addname(
 }
 
 
-STATIC int
-xfs_attr_node_addname_clear_incomplete(
+static int
+xfs_attr_node_remove_attr(
 	struct xfs_attr_item		*attr)
 {
 	struct xfs_da_args		*args = attr->xattri_da_args;
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index 18e157bf19cb..f4f78d841857 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -451,21 +451,21 @@ enum xfs_delattr_state {
 	XFS_DAS_RM_NAME,		/* Remove attr name */
 	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree */
 
-	/* Leaf state set sequence */
+	/* Leaf state set/replace sequence */
 	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a leaf */
 	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a leaf */
 	XFS_DAS_LEAF_REMOVE_OLD,	/* Start removing old attr from leaf */
 	XFS_DAS_LEAF_REMOVE_RMT,	/* A rename is removing remote blocks */
-	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
+	XFS_DAS_LEAF_REMOVE_ATTR,	/* Remove the old attr from a leaf */
 
-	/* Node state set sequence, must match leaf state above */
+	/* Node state set/replace sequence, must match leaf state above */
 	XFS_DAS_NODE_SET_RMT,		/* set a remote xattr from a node */
 	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a node */
 	XFS_DAS_NODE_REMOVE_OLD,	/* Start removing old attr from node */
 	XFS_DAS_NODE_REMOVE_RMT,	/* A rename is removing remote blocks */
-	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
+	XFS_DAS_NODE_REMOVE_ATTR,	/* Remove the old attr from a node */
 
 	XFS_DAS_DONE,			/* finished operation */
 };
@@ -483,13 +483,13 @@ enum xfs_delattr_state {
 	{ XFS_DAS_LEAF_REPLACE,		"XFS_DAS_LEAF_REPLACE" }, \
 	{ XFS_DAS_LEAF_REMOVE_OLD,	"XFS_DAS_LEAF_REMOVE_OLD" }, \
 	{ XFS_DAS_LEAF_REMOVE_RMT,	"XFS_DAS_LEAF_REMOVE_RMT" }, \
-	{ XFS_DAS_RD_LEAF,		"XFS_DAS_RD_LEAF" }, \
+	{ XFS_DAS_LEAF_REMOVE_ATTR,	"XFS_DAS_LEAF_REMOVE_ATTR" }, \
 	{ XFS_DAS_NODE_SET_RMT,		"XFS_DAS_NODE_SET_RMT" }, \
 	{ XFS_DAS_NODE_ALLOC_RMT,	"XFS_DAS_NODE_ALLOC_RMT" },  \
 	{ XFS_DAS_NODE_REPLACE,		"XFS_DAS_NODE_REPLACE" },  \
 	{ XFS_DAS_NODE_REMOVE_OLD,	"XFS_DAS_NODE_REMOVE_OLD" }, \
 	{ XFS_DAS_NODE_REMOVE_RMT,	"XFS_DAS_NODE_REMOVE_RMT" }, \
-	{ XFS_DAS_CLR_FLAG,		"XFS_DAS_CLR_FLAG" }, \
+	{ XFS_DAS_NODE_REMOVE_ATTR,	"XFS_DAS_NODE_REMOVE_ATTR" }, \
 	{ XFS_DAS_DONE,			"XFS_DAS_DONE" }
 
 /*
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 91852b9721e4..3a215d298e62 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -4110,13 +4110,14 @@ TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_OLD);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_RMT);
-TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
+TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_ATTR);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_SET_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_REPLACE);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_OLD);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_RMT);
-TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_ATTR);
+TRACE_DEFINE_ENUM(XFS_DAS_DONE);
 
 DECLARE_EVENT_CLASS(xfs_das_state_class,
 	TP_PROTO(int das, struct xfs_inode *ip),
-- 
2.35.1

Re: [PATCH 10/16] xfs: clean up final attr removal in xfs_attr_set_iter

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Clean up the final leaf/node states in xfs_attr_set_iter() to
> further simplify the highe level state machine and to set the
> completion state correctly.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Ok, I can follow it
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

> ---
>  fs/xfs/libxfs/xfs_attr.c | 72 +++++++++++++++++++++++---------------
> --
>  fs/xfs/libxfs/xfs_attr.h | 12 +++----
>  fs/xfs/xfs_trace.h       |  5 +--
>  3 files changed, 50 insertions(+), 39 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 8762d3a0605a..9dc08d59e4a6 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -61,7 +61,7 @@ STATIC int xfs_attr_node_get(xfs_da_args_t *args);
>  STATIC void xfs_attr_restore_rmt_blk(struct xfs_da_args *args);
>  static int xfs_attr_node_try_addname(struct xfs_attr_item *attr);
>  STATIC int xfs_attr_node_addname_find_attr(struct xfs_attr_item
> *attr);
> -STATIC int xfs_attr_node_addname_clear_incomplete(struct
> xfs_attr_item *attr);
> +STATIC int xfs_attr_node_remove_attr(struct xfs_attr_item *attr);
>  STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
>  				 struct xfs_da_state **state);
>  STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
> @@ -451,6 +451,36 @@ xfs_attr_rmtval_alloc(
>  	return error;
>  }
>  
> +/*
> + * Remove the original attr we have just replaced. This is dependent
> on the
> + * original lookup and insert placing the old attr in args-
> >blkno/args->index
> + * and the new attr in args->blkno2/args->index2.
> + */
> +static int
> +xfs_attr_leaf_remove_attr(
> +	struct xfs_attr_item		*attr)
> +{
> +	struct xfs_da_args              *args = attr->xattri_da_args;
> +	struct xfs_inode		*dp = args->dp;
> +	struct xfs_buf			*bp = NULL;
> +	int				forkoff;
> +	int				error;
> +
> +	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno,
> +				   &bp);
> +	if (error)
> +		return error;
> +
> +	xfs_attr3_leaf_remove(bp, args);
> +
> +	forkoff = xfs_attr_shortform_allfit(bp, dp);
> +	if (forkoff)
> +		error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
> +		/* bp is gone due to xfs_da_shrink_inode */
> +
> +	return error;
> +}
> +
>  /*
>   * Set the attribute specified in @args.
>   * This routine is meant to function as a delayed operation, and may
> return
> @@ -463,9 +493,7 @@ xfs_attr_set_iter(
>  	struct xfs_attr_item		*attr)
>  {
>  	struct xfs_da_args              *args = attr->xattri_da_args;
> -	struct xfs_inode		*dp = args->dp;
> -	struct xfs_buf			*bp = NULL;
> -	int				forkoff, error = 0;
> +	int				error = 0;
>  
>  	/* State machine switch */
>  next_state:
> @@ -564,32 +592,14 @@ xfs_attr_set_iter(
>  		attr->xattri_dela_state++;
>  		break;
>  
> -	case XFS_DAS_RD_LEAF:
> -		/*
> -		 * This is the last step for leaf format. Read the
> block with
> -		 * the old attr, remove the old attr, check for
> shortform
> -		 * conversion and return.
> -		 */
> -		error = xfs_attr3_leaf_read(args->trans, args->dp,
> args->blkno,
> -					   &bp);
> -		if (error)
> -			return error;
> -
> -		xfs_attr3_leaf_remove(bp, args);
> -
> -		forkoff = xfs_attr_shortform_allfit(bp, dp);
> -		if (forkoff)
> -			error = xfs_attr3_leaf_to_shortform(bp, args,
> forkoff);
> -			/* bp is gone due to xfs_da_shrink_inode */
> -
> -		return error;
> +	case XFS_DAS_LEAF_REMOVE_ATTR:
> +		error = xfs_attr_leaf_remove_attr(attr);
> +		attr->xattri_dela_state = XFS_DAS_DONE;
> +		break;
>  
> -	case XFS_DAS_CLR_FLAG:
> -		/*
> -		 * The last state for node format. Look up the old attr
> and
> -		 * remove it.
> -		 */
> -		error = xfs_attr_node_addname_clear_incomplete(attr);
> +	case XFS_DAS_NODE_REMOVE_ATTR:
> +		error = xfs_attr_node_remove_attr(attr);
> +		attr->xattri_dela_state = XFS_DAS_DONE;
>  		break;
>  	default:
>  		ASSERT(0);
> @@ -1262,8 +1272,8 @@ xfs_attr_node_try_addname(
>  }
>  
>  
> -STATIC int
> -xfs_attr_node_addname_clear_incomplete(
> +static int
> +xfs_attr_node_remove_attr(
>  	struct xfs_attr_item		*attr)
>  {
>  	struct xfs_da_args		*args = attr->xattri_da_args;
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index 18e157bf19cb..f4f78d841857 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -451,21 +451,21 @@ enum xfs_delattr_state {
>  	XFS_DAS_RM_NAME,		/* Remove attr name */
>  	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree
> */
>  
> -	/* Leaf state set sequence */
> +	/* Leaf state set/replace sequence */
>  	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a
> leaf */
>  	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a
> leaf */
>  	XFS_DAS_LEAF_REMOVE_OLD,	/* Start removing old attr from leaf
> */
>  	XFS_DAS_LEAF_REMOVE_RMT,	/* A rename is removing remote blocks
> */
> -	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
> +	XFS_DAS_LEAF_REMOVE_ATTR,	/* Remove the old attr from a leaf */
>  
> -	/* Node state set sequence, must match leaf state above */
> +	/* Node state set/replace sequence, must match leaf state above
> */
>  	XFS_DAS_NODE_SET_RMT,		/* set a remote xattr from a
> node */
>  	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a
> node */
>  	XFS_DAS_NODE_REMOVE_OLD,	/* Start removing old attr from node
> */
>  	XFS_DAS_NODE_REMOVE_RMT,	/* A rename is removing remote blocks
> */
> -	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
> +	XFS_DAS_NODE_REMOVE_ATTR,	/* Remove the old attr from a node */
>  
>  	XFS_DAS_DONE,			/* finished operation */
>  };
> @@ -483,13 +483,13 @@ enum xfs_delattr_state {
>  	{ XFS_DAS_LEAF_REPLACE,		"XFS_DAS_LEAF_REPLACE" }, \
>  	{ XFS_DAS_LEAF_REMOVE_OLD,	"XFS_DAS_LEAF_REMOVE_OLD" },
> \
>  	{ XFS_DAS_LEAF_REMOVE_RMT,	"XFS_DAS_LEAF_REMOVE_RMT" },
> \
> -	{ XFS_DAS_RD_LEAF,		"XFS_DAS_RD_LEAF" }, \
> +	{ XFS_DAS_LEAF_REMOVE_ATTR,	"XFS_DAS_LEAF_REMOVE_ATTR" },
> \
>  	{ XFS_DAS_NODE_SET_RMT,		"XFS_DAS_NODE_SET_RMT" }, \
>  	{ XFS_DAS_NODE_ALLOC_RMT,	"XFS_DAS_NODE_ALLOC_RMT" },  \
>  	{ XFS_DAS_NODE_REPLACE,		"XFS_DAS_NODE_REPLACE" },  \
>  	{ XFS_DAS_NODE_REMOVE_OLD,	"XFS_DAS_NODE_REMOVE_OLD" },
> \
>  	{ XFS_DAS_NODE_REMOVE_RMT,	"XFS_DAS_NODE_REMOVE_RMT" },
> \
> -	{ XFS_DAS_CLR_FLAG,		"XFS_DAS_CLR_FLAG" }, \
> +	{ XFS_DAS_NODE_REMOVE_ATTR,	"XFS_DAS_NODE_REMOVE_ATTR" },
> \
>  	{ XFS_DAS_DONE,			"XFS_DAS_DONE" }
>  
>  /*
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 91852b9721e4..3a215d298e62 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4110,13 +4110,14 @@ TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_OLD);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_RMT);
> -TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_ATTR);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_SET_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REPLACE);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_OLD);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_RMT);
> -TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_ATTR);
> +TRACE_DEFINE_ENUM(XFS_DAS_DONE);
>  
>  DECLARE_EVENT_CLASS(xfs_das_state_class,
>  	TP_PROTO(int das, struct xfs_inode *ip),

Re: [PATCH 10/16] xfs: clean up final attr removal in xfs_attr_set_iter

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Clean up the final leaf/node states in xfs_attr_set_iter() to
> further simplify the highe level state machine and to set the
> completion state correctly.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Ok, looks ok to me
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

> ---
>  fs/xfs/libxfs/xfs_attr.c | 72 +++++++++++++++++++++++---------------
> --
>  fs/xfs/libxfs/xfs_attr.h | 12 +++----
>  fs/xfs/xfs_trace.h       |  5 +--
>  3 files changed, 50 insertions(+), 39 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 8762d3a0605a..9dc08d59e4a6 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -61,7 +61,7 @@ STATIC int xfs_attr_node_get(xfs_da_args_t *args);
>  STATIC void xfs_attr_restore_rmt_blk(struct xfs_da_args *args);
>  static int xfs_attr_node_try_addname(struct xfs_attr_item *attr);
>  STATIC int xfs_attr_node_addname_find_attr(struct xfs_attr_item
> *attr);
> -STATIC int xfs_attr_node_addname_clear_incomplete(struct
> xfs_attr_item *attr);
> +STATIC int xfs_attr_node_remove_attr(struct xfs_attr_item *attr);
>  STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
>  				 struct xfs_da_state **state);
>  STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
> @@ -451,6 +451,36 @@ xfs_attr_rmtval_alloc(
>  	return error;
>  }
>  
> +/*
> + * Remove the original attr we have just replaced. This is dependent
> on the
> + * original lookup and insert placing the old attr in args-
> >blkno/args->index
> + * and the new attr in args->blkno2/args->index2.
> + */
> +static int
> +xfs_attr_leaf_remove_attr(
> +	struct xfs_attr_item		*attr)
> +{
> +	struct xfs_da_args              *args = attr->xattri_da_args;
> +	struct xfs_inode		*dp = args->dp;
> +	struct xfs_buf			*bp = NULL;
> +	int				forkoff;
> +	int				error;
> +
> +	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno,
> +				   &bp);
> +	if (error)
> +		return error;
> +
> +	xfs_attr3_leaf_remove(bp, args);
> +
> +	forkoff = xfs_attr_shortform_allfit(bp, dp);
> +	if (forkoff)
> +		error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
> +		/* bp is gone due to xfs_da_shrink_inode */
> +
> +	return error;
> +}
> +
>  /*
>   * Set the attribute specified in @args.
>   * This routine is meant to function as a delayed operation, and may
> return
> @@ -463,9 +493,7 @@ xfs_attr_set_iter(
>  	struct xfs_attr_item		*attr)
>  {
>  	struct xfs_da_args              *args = attr->xattri_da_args;
> -	struct xfs_inode		*dp = args->dp;
> -	struct xfs_buf			*bp = NULL;
> -	int				forkoff, error = 0;
> +	int				error = 0;
>  
>  	/* State machine switch */
>  next_state:
> @@ -564,32 +592,14 @@ xfs_attr_set_iter(
>  		attr->xattri_dela_state++;
>  		break;
>  
> -	case XFS_DAS_RD_LEAF:
> -		/*
> -		 * This is the last step for leaf format. Read the
> block with
> -		 * the old attr, remove the old attr, check for
> shortform
> -		 * conversion and return.
> -		 */
> -		error = xfs_attr3_leaf_read(args->trans, args->dp,
> args->blkno,
> -					   &bp);
> -		if (error)
> -			return error;
> -
> -		xfs_attr3_leaf_remove(bp, args);
> -
> -		forkoff = xfs_attr_shortform_allfit(bp, dp);
> -		if (forkoff)
> -			error = xfs_attr3_leaf_to_shortform(bp, args,
> forkoff);
> -			/* bp is gone due to xfs_da_shrink_inode */
> -
> -		return error;
> +	case XFS_DAS_LEAF_REMOVE_ATTR:
> +		error = xfs_attr_leaf_remove_attr(attr);
> +		attr->xattri_dela_state = XFS_DAS_DONE;
> +		break;
>  
> -	case XFS_DAS_CLR_FLAG:
> -		/*
> -		 * The last state for node format. Look up the old attr
> and
> -		 * remove it.
> -		 */
> -		error = xfs_attr_node_addname_clear_incomplete(attr);
> +	case XFS_DAS_NODE_REMOVE_ATTR:
> +		error = xfs_attr_node_remove_attr(attr);
> +		attr->xattri_dela_state = XFS_DAS_DONE;
>  		break;
>  	default:
>  		ASSERT(0);
> @@ -1262,8 +1272,8 @@ xfs_attr_node_try_addname(
>  }
>  
>  
> -STATIC int
> -xfs_attr_node_addname_clear_incomplete(
> +static int
> +xfs_attr_node_remove_attr(
>  	struct xfs_attr_item		*attr)
>  {
>  	struct xfs_da_args		*args = attr->xattri_da_args;
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index 18e157bf19cb..f4f78d841857 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -451,21 +451,21 @@ enum xfs_delattr_state {
>  	XFS_DAS_RM_NAME,		/* Remove attr name */
>  	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree
> */
>  
> -	/* Leaf state set sequence */
> +	/* Leaf state set/replace sequence */
>  	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a
> leaf */
>  	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a
> leaf */
>  	XFS_DAS_LEAF_REMOVE_OLD,	/* Start removing old attr from leaf
> */
>  	XFS_DAS_LEAF_REMOVE_RMT,	/* A rename is removing remote blocks
> */
> -	XFS_DAS_RD_LEAF,		/* Read in the new leaf */
> +	XFS_DAS_LEAF_REMOVE_ATTR,	/* Remove the old attr from a leaf */
>  
> -	/* Node state set sequence, must match leaf state above */
> +	/* Node state set/replace sequence, must match leaf state above
> */
>  	XFS_DAS_NODE_SET_RMT,		/* set a remote xattr from a
> node */
>  	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a
> node */
>  	XFS_DAS_NODE_REMOVE_OLD,	/* Start removing old attr from node
> */
>  	XFS_DAS_NODE_REMOVE_RMT,	/* A rename is removing remote blocks
> */
> -	XFS_DAS_CLR_FLAG,		/* Clear incomplete flag */
> +	XFS_DAS_NODE_REMOVE_ATTR,	/* Remove the old attr from a node */
>  
>  	XFS_DAS_DONE,			/* finished operation */
>  };
> @@ -483,13 +483,13 @@ enum xfs_delattr_state {
>  	{ XFS_DAS_LEAF_REPLACE,		"XFS_DAS_LEAF_REPLACE" }, \
>  	{ XFS_DAS_LEAF_REMOVE_OLD,	"XFS_DAS_LEAF_REMOVE_OLD" },
> \
>  	{ XFS_DAS_LEAF_REMOVE_RMT,	"XFS_DAS_LEAF_REMOVE_RMT" },
> \
> -	{ XFS_DAS_RD_LEAF,		"XFS_DAS_RD_LEAF" }, \
> +	{ XFS_DAS_LEAF_REMOVE_ATTR,	"XFS_DAS_LEAF_REMOVE_ATTR" },
> \
>  	{ XFS_DAS_NODE_SET_RMT,		"XFS_DAS_NODE_SET_RMT" }, \
>  	{ XFS_DAS_NODE_ALLOC_RMT,	"XFS_DAS_NODE_ALLOC_RMT" },  \
>  	{ XFS_DAS_NODE_REPLACE,		"XFS_DAS_NODE_REPLACE" },  \
>  	{ XFS_DAS_NODE_REMOVE_OLD,	"XFS_DAS_NODE_REMOVE_OLD" },
> \
>  	{ XFS_DAS_NODE_REMOVE_RMT,	"XFS_DAS_NODE_REMOVE_RMT" },
> \
> -	{ XFS_DAS_CLR_FLAG,		"XFS_DAS_CLR_FLAG" }, \
> +	{ XFS_DAS_NODE_REMOVE_ATTR,	"XFS_DAS_NODE_REMOVE_ATTR" },
> \
>  	{ XFS_DAS_DONE,			"XFS_DAS_DONE" }
>  
>  /*
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 91852b9721e4..3a215d298e62 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4110,13 +4110,14 @@ TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_OLD);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_RMT);
> -TRACE_DEFINE_ENUM(XFS_DAS_RD_LEAF);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE_ATTR);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_SET_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REPLACE);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_OLD);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_RMT);
> -TRACE_DEFINE_ENUM(XFS_DAS_CLR_FLAG);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE_ATTR);
> +TRACE_DEFINE_ENUM(XFS_DAS_DONE);
>  
>  DECLARE_EVENT_CLASS(xfs_das_state_class,
>  	TP_PROTO(int das, struct xfs_inode *ip),

[PATCH 11/16] xfs: xfs_attr_set_iter() does not need to return EAGAIN

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

Now that the full xfs_attr_set_iter() state machine always
terminates with either the state being XFS_DAS_DONE on success or
an error on failure, we can get rid of the need for it to return
-EAGAIN whenever it needs to roll the transaction before running
the next state.

That is, we don't need to spray -EAGAIN return states everywhere,
the caller just check the state machine state for completion to
determine what action should be taken next. This greatly simplifies
the code within the state machine implementation as it now only has
to handle 0 for success or -errno for error and it doesn't need to
tell the caller to retry.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 83 +++++++++++++++++-----------------------
 fs/xfs/xfs_attr_item.c   |  2 +
 2 files changed, 37 insertions(+), 48 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 9dc08d59e4a6..a509c998e781 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -303,7 +303,6 @@ xfs_attr_sf_addname(
 	 */
 	xfs_trans_bhold(args->trans, attr->xattri_leaf_bp);
 	attr->xattri_dela_state = XFS_DAS_LEAF_ADD;
-	error = -EAGAIN;
 out:
 	trace_xfs_attr_sf_addname_return(attr->xattri_dela_state, args->dp);
 	return error;
@@ -353,7 +352,6 @@ xfs_attr_leaf_addname(
 		 * retry the add to the newly allocated node block.
 		 */
 		attr->xattri_dela_state = XFS_DAS_NODE_ADD;
-		error = -EAGAIN;
 		goto out;
 	}
 	if (error)
@@ -364,20 +362,24 @@ xfs_attr_leaf_addname(
 	 * or perform more xattr manipulations. Otherwise there is nothing more
 	 * to do and we can return success.
 	 */
-	if (args->rmtblkno) {
+	if (args->rmtblkno)
 		attr->xattri_dela_state = XFS_DAS_LEAF_SET_RMT;
-		error = -EAGAIN;
-	} else if (args->op_flags & XFS_DA_OP_RENAME) {
+	else if (args->op_flags & XFS_DA_OP_RENAME)
 		xfs_attr_dela_state_set_replace(attr, XFS_DAS_LEAF_REPLACE);
-		error = -EAGAIN;
-	} else {
+	else
 		attr->xattri_dela_state = XFS_DAS_DONE;
-	}
 out:
 	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state, args->dp);
 	return error;
 }
 
+/*
+ * Add an entry to a node format attr tree.
+ *
+ * Note that we might still have a leaf here - xfs_attr_is_leaf() cannot tell
+ * the difference between leaf + remote attr blocks and a node format tree,
+ * so we may still end up having to convert from leaf to node format here.
+ */
 static int
 xfs_attr_node_addname(
 	struct xfs_attr_item	*attr)
@@ -392,19 +394,26 @@ xfs_attr_node_addname(
 		return error;
 
 	error = xfs_attr_node_try_addname(attr);
+	if (error == -ENOSPC) {
+		error = xfs_attr3_leaf_to_node(args);
+		if (error)
+			return error;
+		/*
+		 * No state change, we really are in node form now
+		 * but we need the transaction rolled to continue.
+		 */
+		goto out;
+	}
 	if (error)
 		return error;
 
-	if (args->rmtblkno) {
+	if (args->rmtblkno)
 		attr->xattri_dela_state = XFS_DAS_NODE_SET_RMT;
-		error = -EAGAIN;
-	} else if (args->op_flags & XFS_DA_OP_RENAME) {
+	else if (args->op_flags & XFS_DA_OP_RENAME)
 		xfs_attr_dela_state_set_replace(attr, XFS_DAS_NODE_REPLACE);
-		error = -EAGAIN;
-	} else {
+	else
 		attr->xattri_dela_state = XFS_DAS_DONE;
-	}
-
+out:
 	trace_xfs_attr_node_addname_return(attr->xattri_dela_state, args->dp);
 	return error;
 }
@@ -426,7 +435,6 @@ xfs_attr_rmtval_alloc(
 		error = xfs_attr_rmtval_set_blk(attr);
 		if (error)
 			return error;
-		error = -EAGAIN;
 		goto out;
 	}
 
@@ -482,11 +490,12 @@ xfs_attr_leaf_remove_attr(
 }
 
 /*
- * Set the attribute specified in @args.
- * This routine is meant to function as a delayed operation, and may return
- * -EAGAIN when the transaction needs to be rolled.  Calling functions will need
- * to handle this, and recall the function until a successful error code is
- * returned.
+ * Run the attribute operation specified in @attr.
+ *
+ * This routine is meant to function as a delayed operation and will set the
+ * state to XFS_DAS_DONE when the operation is complete.  Calling functions will
+ * need to handle this, and recall the function until either an error or
+ * XFS_DAS_DONE is detected.
  */
 int
 xfs_attr_set_iter(
@@ -547,7 +556,6 @@ xfs_attr_set_iter(
 		 * We must commit the flag value change now to make it atomic
 		 * and then we can start the next trans in series at REMOVE_OLD.
 		 */
-		error = -EAGAIN;
 		attr->xattri_dela_state++;
 		break;
 
@@ -575,8 +583,10 @@ xfs_attr_set_iter(
 	case XFS_DAS_LEAF_REMOVE_RMT:
 	case XFS_DAS_NODE_REMOVE_RMT:
 		error = xfs_attr_rmtval_remove(attr);
-		if (error == -EAGAIN)
+		if (error == -EAGAIN) {
+			error = 0;
 			break;
+		}
 		if (error)
 			return error;
 
@@ -588,7 +598,6 @@ xfs_attr_set_iter(
 		 * can't do that in the same transaction where we removed the
 		 * remote attr blocks.
 		 */
-		error = -EAGAIN;
 		attr->xattri_dela_state++;
 		break;
 
@@ -1200,14 +1209,6 @@ xfs_attr_node_addname_find_attr(
  * This will involve walking down the Btree, and may involve splitting
  * leaf nodes and even splitting intermediate nodes up to and including
  * the root node (a special case of an intermediate node).
- *
- * "Remote" attribute values confuse the issue and atomic rename operations
- * add a whole extra layer of confusion on top of that.
- *
- * This routine is meant to function as a delayed operation, and may return
- * -EAGAIN when the transaction needs to be rolled.  Calling functions will need
- * to handle this, and recall the function until a successful error code is
- *returned.
  */
 static int
 xfs_attr_node_try_addname(
@@ -1229,24 +1230,10 @@ xfs_attr_node_try_addname(
 			/*
 			 * Its really a single leaf node, but it had
 			 * out-of-line values so it looked like it *might*
-			 * have been a b-tree.
+			 * have been a b-tree. Let the caller deal with this.
 			 */
 			xfs_da_state_free(state);
-			state = NULL;
-			error = xfs_attr3_leaf_to_node(args);
-			if (error)
-				goto out;
-
-			/*
-			 * Now that we have converted the leaf to a node, we can
-			 * roll the transaction, and try xfs_attr3_leaf_add
-			 * again on re-entry.  No need to set dela_state to do
-			 * this. dela_state is still unset by this function at
-			 * this point.
-			 */
-			trace_xfs_attr_node_addname_return(
-					attr->xattri_dela_state, args->dp);
-			return -EAGAIN;
+			return -ENOSPC;
 		}
 
 		/*
diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
index b6561861ef01..f2de86756287 100644
--- a/fs/xfs/xfs_attr_item.c
+++ b/fs/xfs/xfs_attr_item.c
@@ -314,6 +314,8 @@ xfs_xattri_finish_update(
 	switch (op) {
 	case XFS_ATTR_OP_FLAGS_SET:
 		error = xfs_attr_set_iter(attr);
+		if (!error && attr->xattri_dela_state != XFS_DAS_DONE)
+			error = -EAGAIN;
 		break;
 	case XFS_ATTR_OP_FLAGS_REMOVE:
 		ASSERT(XFS_IFORK_Q(args->dp));
-- 
2.35.1

Re: [PATCH 11/16] xfs: xfs_attr_set_iter() does not need to return EAGAIN

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Now that the full xfs_attr_set_iter() state machine always
> terminates with either the state being XFS_DAS_DONE on success or
> an error on failure, we can get rid of the need for it to return
> -EAGAIN whenever it needs to roll the transaction before running
> the next state.
> 
> That is, we don't need to spray -EAGAIN return states everywhere,
> the caller just check the state machine state for completion to
> determine what action should be taken next. This greatly simplifies
> the code within the state machine implementation as it now only has
> to handle 0 for success or -errno for error and it doesn't need to
> tell the caller to retry.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Looks ok
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

> ---
>  fs/xfs/libxfs/xfs_attr.c | 83 +++++++++++++++++---------------------
> --
>  fs/xfs/xfs_attr_item.c   |  2 +
>  2 files changed, 37 insertions(+), 48 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 9dc08d59e4a6..a509c998e781 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -303,7 +303,6 @@ xfs_attr_sf_addname(
>  	 */
>  	xfs_trans_bhold(args->trans, attr->xattri_leaf_bp);
>  	attr->xattri_dela_state = XFS_DAS_LEAF_ADD;
> -	error = -EAGAIN;
>  out:
>  	trace_xfs_attr_sf_addname_return(attr->xattri_dela_state, args-
> >dp);
>  	return error;
> @@ -353,7 +352,6 @@ xfs_attr_leaf_addname(
>  		 * retry the add to the newly allocated node block.
>  		 */
>  		attr->xattri_dela_state = XFS_DAS_NODE_ADD;
> -		error = -EAGAIN;
>  		goto out;
>  	}
>  	if (error)
> @@ -364,20 +362,24 @@ xfs_attr_leaf_addname(
>  	 * or perform more xattr manipulations. Otherwise there is
> nothing more
>  	 * to do and we can return success.
>  	 */
> -	if (args->rmtblkno) {
> +	if (args->rmtblkno)
>  		attr->xattri_dela_state = XFS_DAS_LEAF_SET_RMT;
> -		error = -EAGAIN;
> -	} else if (args->op_flags & XFS_DA_OP_RENAME) {
> +	else if (args->op_flags & XFS_DA_OP_RENAME)
>  		xfs_attr_dela_state_set_replace(attr,
> XFS_DAS_LEAF_REPLACE);
> -		error = -EAGAIN;
> -	} else {
> +	else
>  		attr->xattri_dela_state = XFS_DAS_DONE;
> -	}
>  out:
>  	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state,
> args->dp);
>  	return error;
>  }
>  
> +/*
> + * Add an entry to a node format attr tree.
> + *
> + * Note that we might still have a leaf here - xfs_attr_is_leaf()
> cannot tell
> + * the difference between leaf + remote attr blocks and a node
> format tree,
> + * so we may still end up having to convert from leaf to node format
> here.
> + */
>  static int
>  xfs_attr_node_addname(
>  	struct xfs_attr_item	*attr)
> @@ -392,19 +394,26 @@ xfs_attr_node_addname(
>  		return error;
>  
>  	error = xfs_attr_node_try_addname(attr);
> +	if (error == -ENOSPC) {
> +		error = xfs_attr3_leaf_to_node(args);
> +		if (error)
> +			return error;
> +		/*
> +		 * No state change, we really are in node form now
> +		 * but we need the transaction rolled to continue.
> +		 */
> +		goto out;
> +	}
>  	if (error)
>  		return error;
>  
> -	if (args->rmtblkno) {
> +	if (args->rmtblkno)
>  		attr->xattri_dela_state = XFS_DAS_NODE_SET_RMT;
> -		error = -EAGAIN;
> -	} else if (args->op_flags & XFS_DA_OP_RENAME) {
> +	else if (args->op_flags & XFS_DA_OP_RENAME)
>  		xfs_attr_dela_state_set_replace(attr,
> XFS_DAS_NODE_REPLACE);
> -		error = -EAGAIN;
> -	} else {
> +	else
>  		attr->xattri_dela_state = XFS_DAS_DONE;
> -	}
> -
> +out:
>  	trace_xfs_attr_node_addname_return(attr->xattri_dela_state,
> args->dp);
>  	return error;
>  }
> @@ -426,7 +435,6 @@ xfs_attr_rmtval_alloc(
>  		error = xfs_attr_rmtval_set_blk(attr);
>  		if (error)
>  			return error;
> -		error = -EAGAIN;
>  		goto out;
>  	}
>  
> @@ -482,11 +490,12 @@ xfs_attr_leaf_remove_attr(
>  }
>  
>  /*
> - * Set the attribute specified in @args.
> - * This routine is meant to function as a delayed operation, and may
> return
> - * -EAGAIN when the transaction needs to be rolled.  Calling
> functions will need
> - * to handle this, and recall the function until a successful error
> code is
> - * returned.
> + * Run the attribute operation specified in @attr.
> + *
> + * This routine is meant to function as a delayed operation and will
> set the
> + * state to XFS_DAS_DONE when the operation is complete.  Calling
> functions will
> + * need to handle this, and recall the function until either an
> error or
> + * XFS_DAS_DONE is detected.
>   */
>  int
>  xfs_attr_set_iter(
> @@ -547,7 +556,6 @@ xfs_attr_set_iter(
>  		 * We must commit the flag value change now to make it
> atomic
>  		 * and then we can start the next trans in series at
> REMOVE_OLD.
>  		 */
> -		error = -EAGAIN;
>  		attr->xattri_dela_state++;
>  		break;
>  
> @@ -575,8 +583,10 @@ xfs_attr_set_iter(
>  	case XFS_DAS_LEAF_REMOVE_RMT:
>  	case XFS_DAS_NODE_REMOVE_RMT:
>  		error = xfs_attr_rmtval_remove(attr);
> -		if (error == -EAGAIN)
> +		if (error == -EAGAIN) {
> +			error = 0;
>  			break;
> +		}
>  		if (error)
>  			return error;
>  
> @@ -588,7 +598,6 @@ xfs_attr_set_iter(
>  		 * can't do that in the same transaction where we
> removed the
>  		 * remote attr blocks.
>  		 */
> -		error = -EAGAIN;
>  		attr->xattri_dela_state++;
>  		break;
>  
> @@ -1200,14 +1209,6 @@ xfs_attr_node_addname_find_attr(
>   * This will involve walking down the Btree, and may involve
> splitting
>   * leaf nodes and even splitting intermediate nodes up to and
> including
>   * the root node (a special case of an intermediate node).
> - *
> - * "Remote" attribute values confuse the issue and atomic rename
> operations
> - * add a whole extra layer of confusion on top of that.
> - *
> - * This routine is meant to function as a delayed operation, and may
> return
> - * -EAGAIN when the transaction needs to be rolled.  Calling
> functions will need
> - * to handle this, and recall the function until a successful error
> code is
> - *returned.
>   */
>  static int
>  xfs_attr_node_try_addname(
> @@ -1229,24 +1230,10 @@ xfs_attr_node_try_addname(
>  			/*
>  			 * Its really a single leaf node, but it had
>  			 * out-of-line values so it looked like it
> *might*
> -			 * have been a b-tree.
> +			 * have been a b-tree. Let the caller deal with
> this.
>  			 */
>  			xfs_da_state_free(state);
> -			state = NULL;
> -			error = xfs_attr3_leaf_to_node(args);
> -			if (error)
> -				goto out;
> -
> -			/*
> -			 * Now that we have converted the leaf to a
> node, we can
> -			 * roll the transaction, and try
> xfs_attr3_leaf_add
> -			 * again on re-entry.  No need to set
> dela_state to do
> -			 * this. dela_state is still unset by this
> function at
> -			 * this point.
> -			 */
> -			trace_xfs_attr_node_addname_return(
> -					attr->xattri_dela_state, args-
> >dp);
> -			return -EAGAIN;
> +			return -ENOSPC;
>  		}
>  
>  		/*
> diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
> index b6561861ef01..f2de86756287 100644
> --- a/fs/xfs/xfs_attr_item.c
> +++ b/fs/xfs/xfs_attr_item.c
> @@ -314,6 +314,8 @@ xfs_xattri_finish_update(
>  	switch (op) {
>  	case XFS_ATTR_OP_FLAGS_SET:
>  		error = xfs_attr_set_iter(attr);
> +		if (!error && attr->xattri_dela_state != XFS_DAS_DONE)
> +			error = -EAGAIN;
>  		break;
>  	case XFS_ATTR_OP_FLAGS_REMOVE:
>  		ASSERT(XFS_IFORK_Q(args->dp));

[PATCH 12/16] xfs: introduce attr remove initial states into xfs_attr_set_iter

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

Ground work to enable safe recovery of replace operations.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 139 ++++++++++++++++++++++-----------------
 fs/xfs/libxfs/xfs_attr.h |   4 ++
 fs/xfs/xfs_trace.h       |   3 +
 3 files changed, 84 insertions(+), 62 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index a509c998e781..8665b74ddfaf 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -459,6 +459,68 @@ xfs_attr_rmtval_alloc(
 	return error;
 }
 
+/*
+ * Mark an attribute entry INCOMPLETE and save pointers to the relevant buffers
+ * for later deletion of the entry.
+ */
+static int
+xfs_attr_leaf_mark_incomplete(
+	struct xfs_da_args	*args,
+	struct xfs_da_state	*state)
+{
+	int			error;
+
+	/*
+	 * Fill in disk block numbers in the state structure
+	 * so that we can get the buffers back after we commit
+	 * several transactions in the following calls.
+	 */
+	error = xfs_attr_fillstate(state);
+	if (error)
+		return error;
+
+	/*
+	 * Mark the attribute as INCOMPLETE
+	 */
+	return xfs_attr3_leaf_setflag(args);
+}
+
+/*
+ * Initial setup for xfs_attr_node_removename.  Make sure the attr is there and
+ * the blocks are valid.  Attr keys with remote blocks will be marked
+ * incomplete.
+ */
+static
+int xfs_attr_node_removename_setup(
+	struct xfs_attr_item		*attr)
+{
+	struct xfs_da_args		*args = attr->xattri_da_args;
+	struct xfs_da_state		**state = &attr->xattri_da_state;
+	int				error;
+
+	error = xfs_attr_node_hasname(args, state);
+	if (error != -EEXIST)
+		goto out;
+	error = 0;
+
+	ASSERT((*state)->path.blk[(*state)->path.active - 1].bp != NULL);
+	ASSERT((*state)->path.blk[(*state)->path.active - 1].magic ==
+		XFS_ATTR_LEAF_MAGIC);
+
+	if (args->rmtblkno > 0) {
+		error = xfs_attr_leaf_mark_incomplete(args, *state);
+		if (error)
+			goto out;
+
+		error = xfs_attr_rmtval_invalidate(args);
+	}
+out:
+	if (error)
+		xfs_da_state_free(*state);
+
+	return error;
+}
+
 /*
  * Remove the original attr we have just replaced. This is dependent on the
  * original lookup and insert placing the old attr in args->blkno/args->index
@@ -517,6 +579,21 @@ xfs_attr_set_iter(
 	case XFS_DAS_NODE_ADD:
 		return xfs_attr_node_addname(attr);
 
+	case XFS_DAS_SF_REMOVE:
+		attr->xattri_dela_state = XFS_DAS_DONE;
+		return xfs_attr_sf_removename(args);
+	case XFS_DAS_LEAF_REMOVE:
+		attr->xattri_dela_state = XFS_DAS_DONE;
+		return xfs_attr_leaf_removename(args);
+	case XFS_DAS_NODE_REMOVE:
+		error = xfs_attr_node_removename_setup(attr);
+		if (error)
+			return error;
+		attr->xattri_dela_state = XFS_DAS_NODE_REMOVE_RMT;
+		if (args->rmtblkno == 0)
+			attr->xattri_dela_state++;
+		break;
+
 	case XFS_DAS_LEAF_SET_RMT:
 	case XFS_DAS_NODE_SET_RMT:
 		error = xfs_attr_rmtval_find_space(attr);
@@ -1334,68 +1411,6 @@ xfs_attr_node_shrink(
 	return error;
 }
 
-/*
- * Mark an attribute entry INCOMPLETE and save pointers to the relevant buffers
- * for later deletion of the entry.
- */
-STATIC int
-xfs_attr_leaf_mark_incomplete(
-	struct xfs_da_args	*args,
-	struct xfs_da_state	*state)
-{
-	int			error;
-
-	/*
-	 * Fill in disk block numbers in the state structure
-	 * so that we can get the buffers back after we commit
-	 * several transactions in the following calls.
-	 */
-	error = xfs_attr_fillstate(state);
-	if (error)
-		return error;
-
-	/*
-	 * Mark the attribute as INCOMPLETE
-	 */
-	return xfs_attr3_leaf_setflag(args);
-}
-
-/*
- * Initial setup for xfs_attr_node_removename.  Make sure the attr is there and
- * the blocks are valid.  Attr keys with remote blocks will be marked
- * incomplete.
- */
-STATIC
-int xfs_attr_node_removename_setup(
-	struct xfs_attr_item		*attr)
-{
-	struct xfs_da_args		*args = attr->xattri_da_args;
-	struct xfs_da_state		**state = &attr->xattri_da_state;
-	int				error;
-
-	error = xfs_attr_node_hasname(args, state);
-	if (error != -EEXIST)
-		goto out;
-	error = 0;
-
-	ASSERT((*state)->path.blk[(*state)->path.active - 1].bp != NULL);
-	ASSERT((*state)->path.blk[(*state)->path.active - 1].magic ==
-		XFS_ATTR_LEAF_MAGIC);
-
-	if (args->rmtblkno > 0) {
-		error = xfs_attr_leaf_mark_incomplete(args, *state);
-		if (error)
-			goto out;
-
-		error = xfs_attr_rmtval_invalidate(args);
-	}
-out:
-	if (error)
-		xfs_da_state_free(*state);
-
-	return error;
-}
-
 STATIC int
 xfs_attr_node_removename(
 	struct xfs_da_args	*args,
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index f4f78d841857..e4b11ac243d7 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -451,6 +451,10 @@ enum xfs_delattr_state {
 	XFS_DAS_RM_NAME,		/* Remove attr name */
 	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree */
 
+	XFS_DAS_SF_REMOVE,		/* Initial shortform set iter state */
+	XFS_DAS_LEAF_REMOVE,		/* Initial leaf form set iter state */
+	XFS_DAS_NODE_REMOVE,		/* Initial node form set iter state */
+
 	/* Leaf state set/replace sequence */
 	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a leaf */
 	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote blocks */
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 3a215d298e62..c85bab6215e1 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -4105,6 +4105,9 @@ TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
 TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
 TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
+TRACE_DEFINE_ENUM(XFS_DAS_SF_REMOVE);
+TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);
-- 
2.35.1

Re: [PATCH 12/16] xfs: introduce attr remove initial states into xfs_attr_set_iter

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Ground work to enable safe recovery of replace operations.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 139 ++++++++++++++++++++++---------------
> --
>  fs/xfs/libxfs/xfs_attr.h |   4 ++
>  fs/xfs/xfs_trace.h       |   3 +
>  3 files changed, 84 insertions(+), 62 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index a509c998e781..8665b74ddfaf 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -459,6 +459,68 @@ xfs_attr_rmtval_alloc(
>  	return error;
>  }
>  
> +/*
> + * Mark an attribute entry INCOMPLETE and save pointers to the
> relevant buffers
> + * for later deletion of the entry.
> + */
> +static int
> +xfs_attr_leaf_mark_incomplete(
> +	struct xfs_da_args	*args,
> +	struct xfs_da_state	*state)
> +{
> +	int			error;
> +
> +	/*
> +	 * Fill in disk block numbers in the state structure
> +	 * so that we can get the buffers back after we commit
> +	 * several transactions in the following calls.
> +	 */
> +	error = xfs_attr_fillstate(state);
> +	if (error)
> +		return error;
> +
> +	/*
> +	 * Mark the attribute as INCOMPLETE
> +	 */
> +	return xfs_attr3_leaf_setflag(args);
> +}
> +
> +/*
> + * Initial setup for xfs_attr_node_removename.  Make sure the attr
> is there and
> + * the blocks are valid.  Attr keys with remote blocks will be
> marked
> + * incomplete.
> + */
> +static
> +int xfs_attr_node_removename_setup(
> +	struct xfs_attr_item		*attr)
> +{
> +	struct xfs_da_args		*args = attr->xattri_da_args;
> +	struct xfs_da_state		**state = &attr-
> >xattri_da_state;
> +	int				error;
> +
> +	error = xfs_attr_node_hasname(args, state);
> +	if (error != -EEXIST)
> +		goto out;
> +	error = 0;
> +
> +	ASSERT((*state)->path.blk[(*state)->path.active - 1].bp !=
> NULL);
> +	ASSERT((*state)->path.blk[(*state)->path.active - 1].magic ==
> +		XFS_ATTR_LEAF_MAGIC);
> +
> +	if (args->rmtblkno > 0) {
> +		error = xfs_attr_leaf_mark_incomplete(args, *state);
> +		if (error)
> +			goto out;
> +
> +		error = xfs_attr_rmtval_invalidate(args);
> +	}
> +out:
> +	if (error)
> +		xfs_da_state_free(*state);
> +
> +	return error;
> +}
> +
>  /*
>   * Remove the original attr we have just replaced. This is dependent
> on the
>   * original lookup and insert placing the old attr in args-
> >blkno/args->index
> @@ -517,6 +579,21 @@ xfs_attr_set_iter(
>  	case XFS_DAS_NODE_ADD:
>  		return xfs_attr_node_addname(attr);
>  
> +	case XFS_DAS_SF_REMOVE:
> +		attr->xattri_dela_state = XFS_DAS_DONE;
> +		return xfs_attr_sf_removename(args);
> +	case XFS_DAS_LEAF_REMOVE:
> +		attr->xattri_dela_state = XFS_DAS_DONE;
> +		return xfs_attr_leaf_removename(args);
> +	case XFS_DAS_NODE_REMOVE:
> +		error = xfs_attr_node_removename_setup(attr);
> +		if (error)
> +			return error;
> +		attr->xattri_dela_state = XFS_DAS_NODE_REMOVE_RMT;
> +		if (args->rmtblkno == 0)
> +			attr->xattri_dela_state++;
> +		break;
> +
Ok... it took me a little bit to understand why this was here, but it
makes sense after having skipped ahead to the next patch.  We're combining the add/remove code paths to better manage rename for journal replays.  Probably just add a blurb at the top?

"We need to merge the add and remove code paths to enable safe recovery
of replace operations.  Hoist the initial remove states from
xfs_attr_remove_iter into xfs_attr_set_iter.  We will make use of them
in the next patches."

I think the rest looks ok though.
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>


>  	case XFS_DAS_LEAF_SET_RMT:
>  	case XFS_DAS_NODE_SET_RMT:
>  		error = xfs_attr_rmtval_find_space(attr);
> @@ -1334,68 +1411,6 @@ xfs_attr_node_shrink(
>  	return error;
>  }
>  
> -/*
> - * Mark an attribute entry INCOMPLETE and save pointers to the
> relevant buffers
> - * for later deletion of the entry.
> - */
> -STATIC int
> -xfs_attr_leaf_mark_incomplete(
> -	struct xfs_da_args	*args,
> -	struct xfs_da_state	*state)
> -{
> -	int			error;
> -
> -	/*
> -	 * Fill in disk block numbers in the state structure
> -	 * so that we can get the buffers back after we commit
> -	 * several transactions in the following calls.
> -	 */
> -	error = xfs_attr_fillstate(state);
> -	if (error)
> -		return error;
> -
> -	/*
> -	 * Mark the attribute as INCOMPLETE
> -	 */
> -	return xfs_attr3_leaf_setflag(args);
> -}
> -
> -/*
> - * Initial setup for xfs_attr_node_removename.  Make sure the attr
> is there and
> - * the blocks are valid.  Attr keys with remote blocks will be
> marked
> - * incomplete.
> - */
> -STATIC
> -int xfs_attr_node_removename_setup(
> -	struct xfs_attr_item		*attr)
> -{
> -	struct xfs_da_args		*args = attr->xattri_da_args;
> -	struct xfs_da_state		**state = &attr-
> >xattri_da_state;
> -	int				error;
> -
> -	error = xfs_attr_node_hasname(args, state);
> -	if (error != -EEXIST)
> -		goto out;
> -	error = 0;
> -
> -	ASSERT((*state)->path.blk[(*state)->path.active - 1].bp !=
> NULL);
> -	ASSERT((*state)->path.blk[(*state)->path.active - 1].magic ==
> -		XFS_ATTR_LEAF_MAGIC);
> -
> -	if (args->rmtblkno > 0) {
> -		error = xfs_attr_leaf_mark_incomplete(args, *state);
> -		if (error)
> -			goto out;
> -
> -		error = xfs_attr_rmtval_invalidate(args);
> -	}
> -out:
> -	if (error)
> -		xfs_da_state_free(*state);
> -
> -	return error;
> -}
> -
>  STATIC int
>  xfs_attr_node_removename(
>  	struct xfs_da_args	*args,
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index f4f78d841857..e4b11ac243d7 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -451,6 +451,10 @@ enum xfs_delattr_state {
>  	XFS_DAS_RM_NAME,		/* Remove attr name */
>  	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree
> */
>  
> +	XFS_DAS_SF_REMOVE,		/* Initial shortform set iter
> state */
> +	XFS_DAS_LEAF_REMOVE,		/* Initial leaf form set iter
> state */
> +	XFS_DAS_NODE_REMOVE,		/* Initial node form set iter
> state */
> +
>  	/* Leaf state set/replace sequence */
>  	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a
> leaf */
>  	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote
> blocks */
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 3a215d298e62..c85bab6215e1 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4105,6 +4105,9 @@ TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
>  TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
>  TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
> +TRACE_DEFINE_ENUM(XFS_DAS_SF_REMOVE);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REPLACE);

[PATCH 13/16] xfs: switch attr remove to xfs_attri_set_iter

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

Now that xfs_attri_set_iter() has initial states for removing
attributes, switch the pure attribute removal code over to using it.
This requires attrs being removed to always be marked as INCOMPLETE
before we start the removal due to the fact we look up the attr to
remove again in xfs_attr_node_remove_attr().

Note: this drops the fillstate/refillstate optimisations from
the remove path that avoid having to look up the path again after
setting the incomplete flag and removeing remote attrs. Restoring
that optimisation to this path is future Dave's problem.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 26 +++++++++++++++-----------
 fs/xfs/xfs_attr_item.c   | 27 ++++++---------------------
 2 files changed, 21 insertions(+), 32 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 8665b74ddfaf..ccc72c0c3cf5 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -507,13 +507,11 @@ int xfs_attr_node_removename_setup(
 	ASSERT((*state)->path.blk[(*state)->path.active - 1].magic ==
 		XFS_ATTR_LEAF_MAGIC);
 
-	if (args->rmtblkno > 0) {
-		error = xfs_attr_leaf_mark_incomplete(args, *state);
-		if (error)
-			goto out;
-
+	error = xfs_attr_leaf_mark_incomplete(args, *state);
+	if (error)
+		goto out;
+	if (args->rmtblkno > 0)
 		error = xfs_attr_rmtval_invalidate(args);
-	}
 out:
 	if (error)
 		xfs_da_state_free(*state);
@@ -954,6 +952,13 @@ xfs_attr_remove_deferred(
 	if (error)
 		return error;
 
+	if (xfs_attr_is_shortform(args->dp))
+		new->xattri_dela_state = XFS_DAS_SF_REMOVE;
+	else if (xfs_attr_is_leaf(args->dp))
+		new->xattri_dela_state = XFS_DAS_LEAF_REMOVE;
+	else
+		new->xattri_dela_state = XFS_DAS_NODE_REMOVE;
+
 	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
 
 	return 0;
@@ -1342,16 +1347,15 @@ xfs_attr_node_remove_attr(
 {
 	struct xfs_da_args		*args = attr->xattri_da_args;
 	struct xfs_da_state		*state = NULL;
-	struct xfs_mount		*mp = args->dp->i_mount;
 	int				retval = 0;
 	int				error = 0;
 
 	/*
-	 * Re-find the "old" attribute entry after any split ops. The INCOMPLETE
-	 * flag means that we will find the "old" attr, not the "new" one.
+	 * The attr we are removing has already been marked incomplete, so
+	 * we need to set the filter appropriately to re-find the "old"
+	 * attribute entry after any split ops.
 	 */
-	if (!xfs_has_larp(mp))
-		args->attr_filter |= XFS_ATTR_INCOMPLETE;
+	args->attr_filter |= XFS_ATTR_INCOMPLETE;
 	state = xfs_da_state_alloc(args);
 	state->inleaf = 0;
 	error = xfs_da3_node_lookup_int(state, &retval);
diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
index f2de86756287..39af681897a2 100644
--- a/fs/xfs/xfs_attr_item.c
+++ b/fs/xfs/xfs_attr_item.c
@@ -298,12 +298,9 @@ xfs_attrd_item_release(
 STATIC int
 xfs_xattri_finish_update(
 	struct xfs_attr_item		*attr,
-	struct xfs_attrd_log_item	*attrdp,
-	uint32_t			op_flags)
+	struct xfs_attrd_log_item	*attrdp)
 {
 	struct xfs_da_args		*args = attr->xattri_da_args;
-	unsigned int			op = op_flags &
-					     XFS_ATTR_OP_FLAGS_TYPE_MASK;
 	int				error;
 
 	if (XFS_TEST_ERROR(false, args->dp->i_mount, XFS_ERRTAG_LARP)) {
@@ -311,20 +308,9 @@ xfs_xattri_finish_update(
 		goto out;
 	}
 
-	switch (op) {
-	case XFS_ATTR_OP_FLAGS_SET:
-		error = xfs_attr_set_iter(attr);
-		if (!error && attr->xattri_dela_state != XFS_DAS_DONE)
-			error = -EAGAIN;
-		break;
-	case XFS_ATTR_OP_FLAGS_REMOVE:
-		ASSERT(XFS_IFORK_Q(args->dp));
-		error = xfs_attr_remove_iter(attr);
-		break;
-	default:
-		error = -EFSCORRUPTED;
-		break;
-	}
+	error = xfs_attr_set_iter(attr);
+	if (!error && attr->xattri_dela_state != XFS_DAS_DONE)
+		error = -EAGAIN;
 
 out:
 	/*
@@ -435,8 +421,7 @@ xfs_attr_finish_item(
 	 */
 	attr->xattri_da_args->trans = tp;
 
-	error = xfs_xattri_finish_update(attr, done_item,
-					 attr->xattri_op_flags);
+	error = xfs_xattri_finish_update(attr, done_item);
 	if (error != -EAGAIN)
 		kmem_free(attr);
 
@@ -586,7 +571,7 @@ xfs_attri_item_recover(
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, 0);
 
-	ret = xfs_xattri_finish_update(attr, done_item, attrp->alfi_op_flags);
+	ret = xfs_xattri_finish_update(attr, done_item);
 	if (ret == -EAGAIN) {
 		/* There's more work to do, so add it to this transaction */
 		xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_ATTR, &attr->xattri_list);
-- 
2.35.1

Re: [PATCH 13/16] xfs: switch attr remove to xfs_attri_set_iter

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Now that xfs_attri_set_iter() has initial states for removing
> attributes, switch the pure attribute removal code over to using it.
> This requires attrs being removed to always be marked as INCOMPLETE
> before we start the removal due to the fact we look up the attr to
> remove again in xfs_attr_node_remove_attr().
> 
> Note: this drops the fillstate/refillstate optimisations from
> the remove path that avoid having to look up the path again after
> setting the incomplete flag and removeing remote attrs. Restoring
> that optimisation to this path is future Dave's problem.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 26 +++++++++++++++-----------
>  fs/xfs/xfs_attr_item.c   | 27 ++++++---------------------
>  2 files changed, 21 insertions(+), 32 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 8665b74ddfaf..ccc72c0c3cf5 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -507,13 +507,11 @@ int xfs_attr_node_removename_setup(
>  	ASSERT((*state)->path.blk[(*state)->path.active - 1].magic ==
>  		XFS_ATTR_LEAF_MAGIC);
>  
> -	if (args->rmtblkno > 0) {
> -		error = xfs_attr_leaf_mark_incomplete(args, *state);
> -		if (error)
> -			goto out;
> -
> +	error = xfs_attr_leaf_mark_incomplete(args, *state);
> +	if (error)
> +		goto out;
> +	if (args->rmtblkno > 0)
>  		error = xfs_attr_rmtval_invalidate(args);
> -	}
>  out:
>  	if (error)
>  		xfs_da_state_free(*state);
> @@ -954,6 +952,13 @@ xfs_attr_remove_deferred(
>  	if (error)
>  		return error;
>  
> +	if (xfs_attr_is_shortform(args->dp))
> +		new->xattri_dela_state = XFS_DAS_SF_REMOVE;
> +	else if (xfs_attr_is_leaf(args->dp))
> +		new->xattri_dela_state = XFS_DAS_LEAF_REMOVE;
> +	else
> +		new->xattri_dela_state = XFS_DAS_NODE_REMOVE;
> +
Mmmm, same issue here as in patch 4, this initial state configs would
get missed during a replay since these routines are only used in the
delayed attr code path, not the replay code path.


>  	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
>  
>  	return 0;
> @@ -1342,16 +1347,15 @@ xfs_attr_node_remove_attr(
>  {
>  	struct xfs_da_args		*args = attr->xattri_da_args;
>  	struct xfs_da_state		*state = NULL;
> -	struct xfs_mount		*mp = args->dp->i_mount;
>  	int				retval = 0;
>  	int				error = 0;
>  
>  	/*
> -	 * Re-find the "old" attribute entry after any split ops. The
> INCOMPLETE
> -	 * flag means that we will find the "old" attr, not the "new"
> one.
> +	 * The attr we are removing has already been marked incomplete,
> so
> +	 * we need to set the filter appropriately to re-find the "old"
> +	 * attribute entry after any split ops.
>  	 */
> -	if (!xfs_has_larp(mp))
> -		args->attr_filter |= XFS_ATTR_INCOMPLETE;
> +	args->attr_filter |= XFS_ATTR_INCOMPLETE;
>  	state = xfs_da_state_alloc(args);
>  	state->inleaf = 0;
>  	error = xfs_da3_node_lookup_int(state, &retval);
> diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
> index f2de86756287..39af681897a2 100644
> --- a/fs/xfs/xfs_attr_item.c
> +++ b/fs/xfs/xfs_attr_item.c
> @@ -298,12 +298,9 @@ xfs_attrd_item_release(
>  STATIC int
>  xfs_xattri_finish_update(
>  	struct xfs_attr_item		*attr,
> -	struct xfs_attrd_log_item	*attrdp,
> -	uint32_t			op_flags)
> +	struct xfs_attrd_log_item	*attrdp)
>  {
>  	struct xfs_da_args		*args = attr->xattri_da_args;
> -	unsigned int			op = op_flags &
> -					     XFS_ATTR_OP_FLAGS_TYPE_MAS
> K;
>  	int				error;
>  
>  	if (XFS_TEST_ERROR(false, args->dp->i_mount, XFS_ERRTAG_LARP))
> {
> @@ -311,20 +308,9 @@ xfs_xattri_finish_update(
>  		goto out;
>  	}
>  
> -	switch (op) {
> -	case XFS_ATTR_OP_FLAGS_SET:
> -		error = xfs_attr_set_iter(attr);
> -		if (!error && attr->xattri_dela_state != XFS_DAS_DONE)
> -			error = -EAGAIN;
> -		break;
> -	case XFS_ATTR_OP_FLAGS_REMOVE:
> -		ASSERT(XFS_IFORK_Q(args->dp));
> -		error = xfs_attr_remove_iter(attr);
> -		break;
> -	default:
> -		error = -EFSCORRUPTED;
> -		break;
> -	}
> +	error = xfs_attr_set_iter(attr);
> +	if (!error && attr->xattri_dela_state != XFS_DAS_DONE)
> +		error = -EAGAIN;
>  

The concern I have here is that op_flags is recorded and recovered from
the log item (see xfs_attri_item_recover).  Where as xattri_dela_state
is not.  What ever value was set in attr before the shut down would not
be there upon recovery, and with out op_flag we wont know how to
configure it.

I think maybe what you meant to do is log the state?  We need to get
into xfs_attri_log_format and turn alfi_op_flags into
a alfi_dela_state.  I think that would sew together what you are trying
to do here?

Allison

>  out:
>  	/*
> @@ -435,8 +421,7 @@ xfs_attr_finish_item(
>  	 */
>  	attr->xattri_da_args->trans = tp;
>  
> -	error = xfs_xattri_finish_update(attr, done_item,
> -					 attr->xattri_op_flags);
> +	error = xfs_xattri_finish_update(attr, done_item);
>  	if (error != -EAGAIN)
>  		kmem_free(attr);
>  
> @@ -586,7 +571,7 @@ xfs_attri_item_recover(
>  	xfs_ilock(ip, XFS_ILOCK_EXCL);
>  	xfs_trans_ijoin(tp, ip, 0);
>  
> -	ret = xfs_xattri_finish_update(attr, done_item, attrp-
> >alfi_op_flags);
> +	ret = xfs_xattri_finish_update(attr, done_item);
>  	if (ret == -EAGAIN) {
>  		/* There's more work to do, so add it to this
> transaction */
>  		xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_ATTR, &attr-
> >xattri_list);

Re: [PATCH 13/16] xfs: switch attr remove to xfs_attri_set_iter

[Dave Chinner]

On Tue, Apr 26, 2022 at 05:34:36PM -0700, Alli wrote:
> On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > Now that xfs_attri_set_iter() has initial states for removing
> > attributes, switch the pure attribute removal code over to using it.
> > This requires attrs being removed to always be marked as INCOMPLETE
> > before we start the removal due to the fact we look up the attr to
> > remove again in xfs_attr_node_remove_attr().
> > 
> > Note: this drops the fillstate/refillstate optimisations from
> > the remove path that avoid having to look up the path again after
> > setting the incomplete flag and removeing remote attrs. Restoring
> > that optimisation to this path is future Dave's problem.
> > 
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> > ---
> >  fs/xfs/libxfs/xfs_attr.c | 26 +++++++++++++++-----------
> >  fs/xfs/xfs_attr_item.c   | 27 ++++++---------------------
> >  2 files changed, 21 insertions(+), 32 deletions(-)
> > 
> > diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> > index 8665b74ddfaf..ccc72c0c3cf5 100644
> > --- a/fs/xfs/libxfs/xfs_attr.c
> > +++ b/fs/xfs/libxfs/xfs_attr.c
> > @@ -507,13 +507,11 @@ int xfs_attr_node_removename_setup(
> >  	ASSERT((*state)->path.blk[(*state)->path.active - 1].magic ==
> >  		XFS_ATTR_LEAF_MAGIC);
> >  
> > -	if (args->rmtblkno > 0) {
> > -		error = xfs_attr_leaf_mark_incomplete(args, *state);
> > -		if (error)
> > -			goto out;
> > -
> > +	error = xfs_attr_leaf_mark_incomplete(args, *state);
> > +	if (error)
> > +		goto out;
> > +	if (args->rmtblkno > 0)
> >  		error = xfs_attr_rmtval_invalidate(args);
> > -	}
> >  out:
> >  	if (error)
> >  		xfs_da_state_free(*state);
> > @@ -954,6 +952,13 @@ xfs_attr_remove_deferred(
> >  	if (error)
> >  		return error;
> >  
> > +	if (xfs_attr_is_shortform(args->dp))
> > +		new->xattri_dela_state = XFS_DAS_SF_REMOVE;
> > +	else if (xfs_attr_is_leaf(args->dp))
> > +		new->xattri_dela_state = XFS_DAS_LEAF_REMOVE;
> > +	else
> > +		new->xattri_dela_state = XFS_DAS_NODE_REMOVE;
> > +
> Mmmm, same issue here as in patch 4, this initial state configs would
> get missed during a replay since these routines are only used in the
> delayed attr code path, not the replay code path.

*nod*

I'm working on fixing this right now.

> > @@ -311,20 +308,9 @@ xfs_xattri_finish_update(
> >  		goto out;
> >  	}
> >  
> > -	switch (op) {
> > -	case XFS_ATTR_OP_FLAGS_SET:
> > -		error = xfs_attr_set_iter(attr);
> > -		if (!error && attr->xattri_dela_state != XFS_DAS_DONE)
> > -			error = -EAGAIN;
> > -		break;
> > -	case XFS_ATTR_OP_FLAGS_REMOVE:
> > -		ASSERT(XFS_IFORK_Q(args->dp));
> > -		error = xfs_attr_remove_iter(attr);
> > -		break;
> > -	default:
> > -		error = -EFSCORRUPTED;
> > -		break;
> > -	}
> > +	error = xfs_attr_set_iter(attr);
> > +	if (!error && attr->xattri_dela_state != XFS_DAS_DONE)
> > +		error = -EAGAIN;
> >  
> 
> The concern I have here is that op_flags is recorded and recovered from
> the log item (see xfs_attri_item_recover).  Where as xattri_dela_state
> is not.  What ever value was set in attr before the shut down would not
> be there upon recovery, and with out op_flag we wont know how to
> configure it.

Right, that's the real problem with the existing operational order
and intent contents - what is on disk and/or in the journal is not
consistent and is dependent on the state at which the operation
failed. hence to recover from this, we'd need to push the current
state into the intents as well.

That's pretty messy and nasty, and I'm trying to avoid that. This is
the reason why I've reworking the way the logged attribute is logged
and recovered in this series.

When we are doing a pure attr create, we have to consider:

- shortform create is a single transaction operation and so
  never leaves anything behind for recovery to clean up.
- leaf and node insertion of inline attributes are single
  transaction operations and never leave anything for
  recovery to clean up
- short-form to leaf and leaf to node operations roll the
  transaction without changing the attr contents, so if we
  crash after those conversions are committed, recovery only
  needs to create the new attr. IOWs, nothing to clean up
  before we run the create replay.
- creating a remote attr sets the INCOMPLETE flag on the new attr in
  when the name is inserted into the btree, and it is removed when
  the remote attr creation is complete. Hence there's a transient
  state in the journal where the attr is present but INCOMPLETE.

This last state is the problem - if recovery does not remove this
INCOMPLETE xattr, or it does not restart the recovery from the exact
point it failed, we will leave stale INCOMPLETE xattrs in the btree
whenever we recover from a crash. That leaves us with two choices;
either we:

- put a whole lot more state into the intent to enable exact
continuation of the operation (logging state and remote attr extent
target); or
- we just remove the INCOMPLETE xattr and run a normal create
  operation to recreate the entire xattr.


When we are doing a replace, we have similar state based problems -
did we crash during create or removal? IF we are doing the create
first, then we can crash with both a new incomplete and an old valid
xattr of the given name. ANd after we flip the flags over, we have
a new valid and an old incomplete old xattr, and like the create
state we can't tell which is which.

Now what do we do in recovery - which one is the one we have to
remove? Or do we have to remove both? We ahve the same problem as a
pure create - we don't know what to do without knowing the exact
state of the operation.

However, if we change the replace operation to do things in a
different order because we have an intent that stores the new attr
{name, value} pair, we can avoid this whole problem. THat isL

- log the new attr intent atomically with marking the existing attr
  INCOMPLETE.
- remove the old INCOMPLETE attr
- insert the new attr as per the pure create above

If we crash at any point during this operation, we will only ever
see a single INCOMPLETE entry under the name of the new attr,
regardless of whether we failed during the remove of the old xattr
of the create of the new xattr. And because of the intents, we'll
always have the new xattr name+val at recovery time.

Pure remove has the same problem - partial remove still needs
recovery to clean up, but we don't want partially removed xattrs to
ever be visible to userspace. Hence the logged remove operation is:

- log the new attr intent atomically with marking the existing attr
  INCOMPLETE.
- remove the old INCOMPLETE attr

And now the recovery operation is simply "remove the INCOMPLETE
xattr under the logged name".

IOWs, we now have the same recovery path for all three logged xattr
operations:

- remove the INCOMPLETE xattr under the logged name if it exists
  to return the attr fork to a known good state.
- for set/replace, create the new xattr that was logged in the
  intent.

To return to the original question, this means all recovery needs to
know is whether we are recovering a SET/REPLACE or a REMOVE
operation along with the logged xattr name/val pair from the intent.
We don't need to know what state we crashed in, nor do we need to
know partial setup/teardown target/state in the journal because all
we ever need to do to get back to a known good state is teardown
the existing INCOMPLETE xattr....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

[PATCH 14/16] xfs: remove xfs_attri_remove_iter

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

xfs_attri_remove_iter is not used anymore, so remove it and all the
infrastructure it uses and is needed to drive it.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 210 ++++-----------------------------------
 1 file changed, 18 insertions(+), 192 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index ccc72c0c3cf5..34c31077b08f 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -1340,6 +1340,24 @@ xfs_attr_node_try_addname(
 	return error;
 }
 
+static int
+xfs_attr_node_removename(
+	struct xfs_da_args	*args,
+	struct xfs_da_state	*state)
+{
+	struct xfs_da_state_blk	*blk;
+	int			retval;
+
+	/*
+	 * Remove the name and update the hashvals in the tree.
+	 */
+	blk = &state->path.blk[state->path.active-1];
+	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
+	retval = xfs_attr3_leaf_remove(blk->bp, args);
+	xfs_da3_fixhashpath(state, &state->path);
+
+	return retval;
+}
 
 static int
 xfs_attr_node_remove_attr(
@@ -1382,198 +1400,6 @@ xfs_attr_node_remove_attr(
 	return retval;
 }
 
-/*
- * Shrink an attribute from leaf to shortform
- */
-STATIC int
-xfs_attr_node_shrink(
-	struct xfs_da_args	*args,
-	struct xfs_da_state     *state)
-{
-	struct xfs_inode	*dp = args->dp;
-	int			error, forkoff;
-	struct xfs_buf		*bp;
-
-	/*
-	 * Have to get rid of the copy of this dabuf in the state.
-	 */
-	ASSERT(state->path.active == 1);
-	ASSERT(state->path.blk[0].bp);
-	state->path.blk[0].bp = NULL;
-
-	error = xfs_attr3_leaf_read(args->trans, args->dp, 0, &bp);
-	if (error)
-		return error;
-
-	forkoff = xfs_attr_shortform_allfit(bp, dp);
-	if (forkoff) {
-		error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
-		/* bp is gone due to xfs_da_shrink_inode */
-	} else
-		xfs_trans_brelse(args->trans, bp);
-
-	return error;
-}
-
-STATIC int
-xfs_attr_node_removename(
-	struct xfs_da_args	*args,
-	struct xfs_da_state	*state)
-{
-	struct xfs_da_state_blk	*blk;
-	int			retval;
-
-	/*
-	 * Remove the name and update the hashvals in the tree.
-	 */
-	blk = &state->path.blk[state->path.active-1];
-	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
-	retval = xfs_attr3_leaf_remove(blk->bp, args);
-	xfs_da3_fixhashpath(state, &state->path);
-
-	return retval;
-}
-
-/*
- * Remove the attribute specified in @args.
- *
- * This will involve walking down the Btree, and may involve joining
- * leaf nodes and even joining intermediate nodes up to and including
- * the root node (a special case of an intermediate node).
- *
- * This routine is meant to function as either an in-line or delayed operation,
- * and may return -EAGAIN when the transaction needs to be rolled.  Calling
- * functions will need to handle this, and call the function until a
- * successful error code is returned.
- */
-int
-xfs_attr_remove_iter(
-	struct xfs_attr_item		*attr)
-{
-	struct xfs_da_args		*args = attr->xattri_da_args;
-	struct xfs_da_state		*state = attr->xattri_da_state;
-	int				retval, error = 0;
-	struct xfs_inode		*dp = args->dp;
-
-	trace_xfs_attr_node_removename(args);
-
-	switch (attr->xattri_dela_state) {
-	case XFS_DAS_UNINIT:
-		if (!xfs_inode_hasattr(dp))
-			return -ENOATTR;
-
-		/*
-		 * Shortform or leaf formats don't require transaction rolls and
-		 * thus state transitions. Call the right helper and return.
-		 */
-		if (dp->i_afp->if_format == XFS_DINODE_FMT_LOCAL)
-			return xfs_attr_sf_removename(args);
-
-		if (xfs_attr_is_leaf(dp))
-			return xfs_attr_leaf_removename(args);
-
-		/*
-		 * Node format may require transaction rolls. Set up the
-		 * state context and fall into the state machine.
-		 */
-		if (!attr->xattri_da_state) {
-			error = xfs_attr_node_removename_setup(attr);
-			if (error)
-				return error;
-			state = attr->xattri_da_state;
-		}
-
-		fallthrough;
-	case XFS_DAS_RMTBLK:
-		attr->xattri_dela_state = XFS_DAS_RMTBLK;
-
-		/*
-		 * If there is an out-of-line value, de-allocate the blocks.
-		 * This is done before we remove the attribute so that we don't
-		 * overflow the maximum size of a transaction and/or hit a
-		 * deadlock.
-		 */
-		if (args->rmtblkno > 0) {
-			/*
-			 * May return -EAGAIN. Roll and repeat until all remote
-			 * blocks are removed.
-			 */
-			error = xfs_attr_rmtval_remove(attr);
-			if (error == -EAGAIN) {
-				trace_xfs_attr_remove_iter_return(
-					attr->xattri_dela_state, args->dp);
-				return error;
-			} else if (error) {
-				goto out;
-			}
-
-			/*
-			 * Refill the state structure with buffers (the prior
-			 * calls released our buffers) and close out this
-			 * transaction before proceeding.
-			 */
-			ASSERT(args->rmtblkno == 0);
-			error = xfs_attr_refillstate(state);
-			if (error)
-				goto out;
-
-			attr->xattri_dela_state = XFS_DAS_RM_NAME;
-			trace_xfs_attr_remove_iter_return(
-					attr->xattri_dela_state, args->dp);
-			return -EAGAIN;
-		}
-
-		fallthrough;
-	case XFS_DAS_RM_NAME:
-		/*
-		 * If we came here fresh from a transaction roll, reattach all
-		 * the buffers to the current transaction.
-		 */
-		if (attr->xattri_dela_state == XFS_DAS_RM_NAME) {
-			error = xfs_attr_refillstate(state);
-			if (error)
-				goto out;
-		}
-
-		retval = xfs_attr_node_removename(args, state);
-
-		/*
-		 * Check to see if the tree needs to be collapsed. If so, roll
-		 * the transacton and fall into the shrink state.
-		 */
-		if (retval && (state->path.active > 1)) {
-			error = xfs_da3_join(state);
-			if (error)
-				goto out;
-
-			attr->xattri_dela_state = XFS_DAS_RM_SHRINK;
-			trace_xfs_attr_remove_iter_return(
-					attr->xattri_dela_state, args->dp);
-			return -EAGAIN;
-		}
-
-		fallthrough;
-	case XFS_DAS_RM_SHRINK:
-		/*
-		 * If the result is small enough, push it all into the inode.
-		 * This is our final state so it's safe to return a dirty
-		 * transaction.
-		 */
-		if (xfs_attr_is_leaf(dp))
-			error = xfs_attr_node_shrink(args, state);
-		ASSERT(error != -EAGAIN);
-		break;
-	default:
-		ASSERT(0);
-		error = -EINVAL;
-		goto out;
-	}
-out:
-	if (state)
-		xfs_da_state_free(state);
-	return error;
-}
-
 /*
  * Fill in the disk block numbers in the state structure for the buffers
  * that are attached to the state structure.
-- 
2.35.1

Re: [PATCH 14/16] xfs: remove xfs_attri_remove_iter

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> xfs_attri_remove_iter is not used anymore, so remove it and all the
> infrastructure it uses and is needed to drive it.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/libxfs/xfs_attr.c | 210 ++++---------------------------------
> --
>  1 file changed, 18 insertions(+), 192 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index ccc72c0c3cf5..34c31077b08f 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -1340,6 +1340,24 @@ xfs_attr_node_try_addname(
>  	return error;
>  }
>  
> +static int
> +xfs_attr_node_removename(
> +	struct xfs_da_args	*args,
> +	struct xfs_da_state	*state)
> +{
> +	struct xfs_da_state_blk	*blk;
> +	int			retval;
> +
> +	/*
> +	 * Remove the name and update the hashvals in the tree.
> +	 */
> +	blk = &state->path.blk[state->path.active-1];
> +	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
> +	retval = xfs_attr3_leaf_remove(blk->bp, args);
> +	xfs_da3_fixhashpath(state, &state->path);
> +
> +	return retval;
> +}
>  
>  static int
>  xfs_attr_node_remove_attr(
> @@ -1382,198 +1400,6 @@ xfs_attr_node_remove_attr(
>  	return retval;
>  }
>  
> -/*
> - * Shrink an attribute from leaf to shortform
> - */
> -STATIC int
> -xfs_attr_node_shrink(
> -	struct xfs_da_args	*args,
> -	struct xfs_da_state     *state)
> -{
> -	struct xfs_inode	*dp = args->dp;
> -	int			error, forkoff;
> -	struct xfs_buf		*bp;
> -
> -	/*
> -	 * Have to get rid of the copy of this dabuf in the state.
> -	 */
> -	ASSERT(state->path.active == 1);
> -	ASSERT(state->path.blk[0].bp);
> -	state->path.blk[0].bp = NULL;
> -
> -	error = xfs_attr3_leaf_read(args->trans, args->dp, 0, &bp);
> -	if (error)
> -		return error;
> -
> -	forkoff = xfs_attr_shortform_allfit(bp, dp);
> -	if (forkoff) {
> -		error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
> -		/* bp is gone due to xfs_da_shrink_inode */
> -	} else
> -		xfs_trans_brelse(args->trans, bp);
> -
> -	return error;
> -}
> -
> -STATIC int
> -xfs_attr_node_removename(
> -	struct xfs_da_args	*args,
> -	struct xfs_da_state	*state)
> -{
> -	struct xfs_da_state_blk	*blk;
> -	int			retval;
> -
> -	/*
> -	 * Remove the name and update the hashvals in the tree.
> -	 */
> -	blk = &state->path.blk[state->path.active-1];
> -	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
> -	retval = xfs_attr3_leaf_remove(blk->bp, args);
> -	xfs_da3_fixhashpath(state, &state->path);
> -
> -	return retval;
> -}
> -
> -/*
> - * Remove the attribute specified in @args.
> - *
> - * This will involve walking down the Btree, and may involve joining
> - * leaf nodes and even joining intermediate nodes up to and
> including
> - * the root node (a special case of an intermediate node).
> - *
> - * This routine is meant to function as either an in-line or delayed
> operation,
> - * and may return -EAGAIN when the transaction needs to be
> rolled.  Calling
> - * functions will need to handle this, and call the function until a
> - * successful error code is returned.
> - */
> -int
> -xfs_attr_remove_iter(
> -	struct xfs_attr_item		*attr)
> -{
> -	struct xfs_da_args		*args = attr->xattri_da_args;
> -	struct xfs_da_state		*state = attr-
> >xattri_da_state;
> -	int				retval, error = 0;
> -	struct xfs_inode		*dp = args->dp;
> -
> -	trace_xfs_attr_node_removename(args);
> -
> -	switch (attr->xattri_dela_state) {
> -	case XFS_DAS_UNINIT:
> -		if (!xfs_inode_hasattr(dp))
> -			return -ENOATTR;
> -
> -		/*
> -		 * Shortform or leaf formats don't require transaction
> rolls and
> -		 * thus state transitions. Call the right helper and
> return.
> -		 */
> -		if (dp->i_afp->if_format == XFS_DINODE_FMT_LOCAL)
> -			return xfs_attr_sf_removename(args);
> -
> -		if (xfs_attr_is_leaf(dp))
> -			return xfs_attr_leaf_removename(args);
> -
> -		/*
> -		 * Node format may require transaction rolls. Set up
> the
> -		 * state context and fall into the state machine.
> -		 */
> -		if (!attr->xattri_da_state) {
> -			error = xfs_attr_node_removename_setup(attr);
> -			if (error)
> -				return error;
> -			state = attr->xattri_da_state;
> -		}
> -
> -		fallthrough;
> -	case XFS_DAS_RMTBLK:
> -		attr->xattri_dela_state = XFS_DAS_RMTBLK;
> -
> -		/*
> -		 * If there is an out-of-line value, de-allocate the
> blocks.
> -		 * This is done before we remove the attribute so that
> we don't
> -		 * overflow the maximum size of a transaction and/or
> hit a
> -		 * deadlock.
> -		 */
> -		if (args->rmtblkno > 0) {
> -			/*
> -			 * May return -EAGAIN. Roll and repeat until
> all remote
> -			 * blocks are removed.
> -			 */
> -			error = xfs_attr_rmtval_remove(attr);
> -			if (error == -EAGAIN) {
> -				trace_xfs_attr_remove_iter_return(
> -					attr->xattri_dela_state, args-
> >dp);
> -				return error;
> -			} else if (error) {
> -				goto out;
> -			}
> -
> -			/*
> -			 * Refill the state structure with buffers (the
> prior
> -			 * calls released our buffers) and close out
> this
> -			 * transaction before proceeding.
> -			 */
> -			ASSERT(args->rmtblkno == 0);
> -			error = xfs_attr_refillstate(state);

I think you can remove xfs_attr_refillstate too.  I'm getting some
compiler gripes about that being declared but not used, and I'm pretty
sure this was the last call to it, so probably it can go too.  Other
than that this patch looks ok.

Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

> -			if (error)
> -				goto out;
> -
> -			attr->xattri_dela_state = XFS_DAS_RM_NAME;
> -			trace_xfs_attr_remove_iter_return(
> -					attr->xattri_dela_state, args-
> >dp);
> -			return -EAGAIN;
> -		}
> -
> -		fallthrough;
> -	case XFS_DAS_RM_NAME:
> -		/*
> -		 * If we came here fresh from a transaction roll,
> reattach all
> -		 * the buffers to the current transaction.
> -		 */
> -		if (attr->xattri_dela_state == XFS_DAS_RM_NAME) {
> -			error = xfs_attr_refillstate(state);
> -			if (error)
> -				goto out;
> -		}
> -
> -		retval = xfs_attr_node_removename(args, state);
> -
> -		/*
> -		 * Check to see if the tree needs to be collapsed. If
> so, roll
> -		 * the transacton and fall into the shrink state.
> -		 */
> -		if (retval && (state->path.active > 1)) {
> -			error = xfs_da3_join(state);
> -			if (error)
> -				goto out;
> -
> -			attr->xattri_dela_state = XFS_DAS_RM_SHRINK;
> -			trace_xfs_attr_remove_iter_return(
> -					attr->xattri_dela_state, args-
> >dp);
> -			return -EAGAIN;
> -		}
> -
> -		fallthrough;
> -	case XFS_DAS_RM_SHRINK:
> -		/*
> -		 * If the result is small enough, push it all into the
> inode.
> -		 * This is our final state so it's safe to return a
> dirty
> -		 * transaction.
> -		 */
> -		if (xfs_attr_is_leaf(dp))
> -			error = xfs_attr_node_shrink(args, state);
> -		ASSERT(error != -EAGAIN);
> -		break;
> -	default:
> -		ASSERT(0);
> -		error = -EINVAL;
> -		goto out;
> -	}
> -out:
> -	if (state)
> -		xfs_da_state_free(state);
> -	return error;
> -}
> -
>  /*
>   * Fill in the disk block numbers in the state structure for the
> buffers
>   * that are attached to the state structure.

Re: [PATCH 14/16] xfs: remove xfs_attri_remove_iter

[Dave Chinner]

On Tue, Apr 26, 2022 at 05:34:47PM -0700, Alli wrote:
> On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > xfs_attri_remove_iter is not used anymore, so remove it and all the
> > infrastructure it uses and is needed to drive it.
> > 
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> > ---
> > -	case XFS_DAS_RMTBLK:
> > -		attr->xattri_dela_state = XFS_DAS_RMTBLK;
> > -
> > -		/*
> > -		 * If there is an out-of-line value, de-allocate the
> > blocks.
> > -		 * This is done before we remove the attribute so that
> > we don't
> > -		 * overflow the maximum size of a transaction and/or
> > hit a
> > -		 * deadlock.
> > -		 */
> > -		if (args->rmtblkno > 0) {
> > -			/*
> > -			 * May return -EAGAIN. Roll and repeat until
> > all remote
> > -			 * blocks are removed.
> > -			 */
> > -			error = xfs_attr_rmtval_remove(attr);
> > -			if (error == -EAGAIN) {
> > -				trace_xfs_attr_remove_iter_return(
> > -					attr->xattri_dela_state, args-
> > >dp);
> > -				return error;
> > -			} else if (error) {
> > -				goto out;
> > -			}
> > -
> > -			/*
> > -			 * Refill the state structure with buffers (the
> > prior
> > -			 * calls released our buffers) and close out
> > this
> > -			 * transaction before proceeding.
> > -			 */
> > -			ASSERT(args->rmtblkno == 0);
> > -			error = xfs_attr_refillstate(state);
> 
> I think you can remove xfs_attr_refillstate too.  I'm getting some
> compiler gripes about that being declared but not used, and I'm pretty
> sure this was the last call to it, so probably it can go too.

I'm going to ifdef it out for now, which will remove the compiler
warning. I'll leave a comment explaining why it's been left there
unused for the moment. That is a bit of a long story.....

.... so it's Story Time! :)

The xfs_attr_savestate(), xfs_attr_refillstate() pair are for saving
the state path cursor that points to the name entry in the btree so
we don't have to look it up again after we've removed the remote
value blocks.

Removing the remote value extents trashes the state cursor (points to
remote value extents that have been removed on return, not the name
entry in the btree), so to avoid doing another tree walk we save the
disk addresses of the path blocks before remote extent removal and
restore them to the state cursor afterwards.

This avoids having to walk the hash tree to find the data block that
contains the name entry again to remove that. It's an optimisation
that I removed when combining the two state machines because it hurt
my brain trying to reconcile the two paths. Hence I ended up using
the simpler _set_iter() path that just does the lookup a second time
when I combined the state machines rather than the more complex
save/restore path in the remove_iter state machine.

I left the code there because I want to re-introduce the
optimisation in future - it will benefit both the replace and remove
paths - but I want to get the code working correctly first before I
worry too much about intricate performance optimisations like this.

> Other
> than that this patch looks ok.
> 
> Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

Thanks!

-Dave.
-- 
Dave Chinner
david@fromorbit.com

[PATCH 15/16] xfs: split attr replace op setup from create op setup

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

In preparation for having a different replace algorithm when LARP
mode is active.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 194 ++++++++++++++++++++++-----------------
 fs/xfs/libxfs/xfs_attr.h |   2 -
 2 files changed, 112 insertions(+), 84 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 34c31077b08f..772506d44bfa 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -724,6 +724,96 @@ xfs_attr_lookup(
 	return xfs_attr_node_hasname(args, NULL);
 }
 
+static int
+xfs_attr_item_init(
+	struct xfs_da_args	*args,
+	unsigned int		op_flags,	/* op flag (set or remove) */
+	struct xfs_attr_item	**attr)		/* new xfs_attr_item */
+{
+
+	struct xfs_attr_item	*new;
+
+	new = kmem_zalloc(sizeof(struct xfs_attr_item), KM_NOFS);
+	new->xattri_op_flags = op_flags;
+	new->xattri_da_args = args;
+
+	*attr = new;
+	return 0;
+}
+
+/* Sets an attribute for an inode as a deferred operation */
+static int
+xfs_attr_defer_add(
+	struct xfs_da_args	*args)
+{
+	struct xfs_attr_item	*new;
+	int			error = 0;
+
+	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
+	if (error)
+		return error;
+
+	if (xfs_attr_is_shortform(args->dp))
+		new->xattri_dela_state = XFS_DAS_SF_ADD;
+	else if (xfs_attr_is_leaf(args->dp))
+		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
+	else
+		new->xattri_dela_state = XFS_DAS_NODE_ADD;
+
+	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
+
+	return 0;
+}
+
+/* Sets an attribute for an inode as a deferred operation */
+static int
+xfs_attr_defer_replace(
+	struct xfs_da_args	*args)
+{
+	struct xfs_attr_item	*new;
+	int			error = 0;
+
+	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
+	if (error)
+		return error;
+
+	if (xfs_attr_is_shortform(args->dp))
+		new->xattri_dela_state = XFS_DAS_SF_ADD;
+	else if (xfs_attr_is_leaf(args->dp))
+		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
+	else
+		new->xattri_dela_state = XFS_DAS_NODE_ADD;
+
+	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
+
+	return 0;
+}
+
+/* Removes an attribute for an inode as a deferred operation */
+static int
+xfs_attr_defer_remove(
+	struct xfs_da_args	*args)
+{
+
+	struct xfs_attr_item	*new;
+	int			error;
+
+	error  = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_REMOVE, &new);
+	if (error)
+		return error;
+
+	if (xfs_attr_is_shortform(args->dp))
+		new->xattri_dela_state = XFS_DAS_SF_REMOVE;
+	else if (xfs_attr_is_leaf(args->dp))
+		new->xattri_dela_state = XFS_DAS_LEAF_REMOVE;
+	else
+		new->xattri_dela_state = XFS_DAS_NODE_REMOVE;
+
+	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
+
+	return 0;
+}
+
 /*
  * Note: If args->value is NULL the attribute will be removed, just like the
  * Linux ->setattr API.
@@ -812,29 +902,35 @@ xfs_attr_set(
 	}
 
 	error = xfs_attr_lookup(args);
-	if (args->value) {
-		if (error == -EEXIST && (args->attr_flags & XATTR_CREATE))
-			goto out_trans_cancel;
-		if (error == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
-			goto out_trans_cancel;
-		if (error != -ENOATTR && error != -EEXIST)
+	switch (error) {
+	case -EEXIST:
+		/* if no value, we are performing a remove operation */
+		if (!args->value) {
+			error = xfs_attr_defer_remove(args);
+			break;
+		}
+		/* Pure create fails if the attr already exists */
+		if (args->attr_flags & XATTR_CREATE)
 			goto out_trans_cancel;
 
-		error = xfs_attr_set_deferred(args);
-		if (error)
+		error = xfs_attr_defer_replace(args);
+		break;
+	case -ENOATTR:
+		/* Can't remove what isn't there. */
+		if (!args->value)
 			goto out_trans_cancel;
 
-		/* shortform attribute has already been committed */
-		if (!args->trans)
-			goto out_unlock;
-	} else {
-		if (error != -EEXIST)
+		/* Pure replace fails if no existing attr to replace. */
+		if (args->attr_flags & XATTR_REPLACE)
 			goto out_trans_cancel;
 
-		error = xfs_attr_remove_deferred(args);
-		if (error)
-			goto out_trans_cancel;
+		error = xfs_attr_defer_add(args);
+		break;
+	default:
+		goto out_trans_cancel;
 	}
+	if (error)
+		goto out_trans_cancel;
 
 	/*
 	 * If this is a synchronous mount, make sure that the
@@ -898,72 +994,6 @@ xfs_attrd_destroy_cache(void)
 	xfs_attrd_cache = NULL;
 }
 
-STATIC int
-xfs_attr_item_init(
-	struct xfs_da_args	*args,
-	unsigned int		op_flags,	/* op flag (set or remove) */
-	struct xfs_attr_item	**attr)		/* new xfs_attr_item */
-{
-
-	struct xfs_attr_item	*new;
-
-	new = kmem_zalloc(sizeof(struct xfs_attr_item), KM_NOFS);
-	new->xattri_op_flags = op_flags;
-	new->xattri_da_args = args;
-
-	*attr = new;
-	return 0;
-}
-
-/* Sets an attribute for an inode as a deferred operation */
-int
-xfs_attr_set_deferred(
-	struct xfs_da_args	*args)
-{
-	struct xfs_attr_item	*new;
-	int			error = 0;
-
-	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
-	if (error)
-		return error;
-
-	if (xfs_attr_is_shortform(args->dp))
-		new->xattri_dela_state = XFS_DAS_SF_ADD;
-	else if (xfs_attr_is_leaf(args->dp))
-		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
-	else
-		new->xattri_dela_state = XFS_DAS_NODE_ADD;
-
-	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
-
-	return 0;
-}
-
-/* Removes an attribute for an inode as a deferred operation */
-int
-xfs_attr_remove_deferred(
-	struct xfs_da_args	*args)
-{
-
-	struct xfs_attr_item	*new;
-	int			error;
-
-	error  = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_REMOVE, &new);
-	if (error)
-		return error;
-
-	if (xfs_attr_is_shortform(args->dp))
-		new->xattri_dela_state = XFS_DAS_SF_REMOVE;
-	else if (xfs_attr_is_leaf(args->dp))
-		new->xattri_dela_state = XFS_DAS_LEAF_REMOVE;
-	else
-		new->xattri_dela_state = XFS_DAS_NODE_REMOVE;
-
-	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
-
-	return 0;
-}
-
 /*========================================================================
  * External routines when attribute list is inside the inode
  *========================================================================*/
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index e4b11ac243d7..cac7dfcf2dbe 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -559,8 +559,6 @@ bool xfs_attr_namecheck(const void *name, size_t length);
 int xfs_attr_calc_size(struct xfs_da_args *args, int *local);
 void xfs_init_attr_trans(struct xfs_da_args *args, struct xfs_trans_res *tres,
 			 unsigned int *total);
-int xfs_attr_set_deferred(struct xfs_da_args *args);
-int xfs_attr_remove_deferred(struct xfs_da_args *args);
 
 extern struct kmem_cache	*xfs_attri_cache;
 extern struct kmem_cache	*xfs_attrd_cache;
-- 
2.35.1

Re: [PATCH 15/16] xfs: split attr replace op setup from create op setup

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> In preparation for having a different replace algorithm when LARP
> mode is active.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Looks fine
Reviewed-by: Allison Henderson<allison.henderson@oracle.com>

> ---
>  fs/xfs/libxfs/xfs_attr.c | 194 ++++++++++++++++++++++---------------
> --
>  fs/xfs/libxfs/xfs_attr.h |   2 -
>  2 files changed, 112 insertions(+), 84 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 34c31077b08f..772506d44bfa 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -724,6 +724,96 @@ xfs_attr_lookup(
>  	return xfs_attr_node_hasname(args, NULL);
>  }
>  
> +static int
> +xfs_attr_item_init(
> +	struct xfs_da_args	*args,
> +	unsigned int		op_flags,	/* op flag (set or
> remove) */
> +	struct xfs_attr_item	**attr)		/* new xfs_attr_item
> */
> +{
> +
> +	struct xfs_attr_item	*new;
> +
> +	new = kmem_zalloc(sizeof(struct xfs_attr_item), KM_NOFS);
> +	new->xattri_op_flags = op_flags;
> +	new->xattri_da_args = args;
> +
> +	*attr = new;
> +	return 0;
> +}
> +
> +/* Sets an attribute for an inode as a deferred operation */
> +static int
> +xfs_attr_defer_add(
> +	struct xfs_da_args	*args)
> +{
> +	struct xfs_attr_item	*new;
> +	int			error = 0;
> +
> +	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
> +	if (error)
> +		return error;
> +
> +	if (xfs_attr_is_shortform(args->dp))
> +		new->xattri_dela_state = XFS_DAS_SF_ADD;
> +	else if (xfs_attr_is_leaf(args->dp))
> +		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
> +	else
> +		new->xattri_dela_state = XFS_DAS_NODE_ADD;
> +
> +	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
> +
> +	return 0;
> +}
> +
> +/* Sets an attribute for an inode as a deferred operation */
> +static int
> +xfs_attr_defer_replace(
> +	struct xfs_da_args	*args)
> +{
> +	struct xfs_attr_item	*new;
> +	int			error = 0;
> +
> +	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
> +	if (error)
> +		return error;
> +
> +	if (xfs_attr_is_shortform(args->dp))
> +		new->xattri_dela_state = XFS_DAS_SF_ADD;
> +	else if (xfs_attr_is_leaf(args->dp))
> +		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
> +	else
> +		new->xattri_dela_state = XFS_DAS_NODE_ADD;
> +
> +	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
> +
> +	return 0;
> +}
> +
> +/* Removes an attribute for an inode as a deferred operation */
> +static int
> +xfs_attr_defer_remove(
> +	struct xfs_da_args	*args)
> +{
> +
> +	struct xfs_attr_item	*new;
> +	int			error;
> +
> +	error  = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_REMOVE,
> &new);
> +	if (error)
> +		return error;
> +
> +	if (xfs_attr_is_shortform(args->dp))
> +		new->xattri_dela_state = XFS_DAS_SF_REMOVE;
> +	else if (xfs_attr_is_leaf(args->dp))
> +		new->xattri_dela_state = XFS_DAS_LEAF_REMOVE;
> +	else
> +		new->xattri_dela_state = XFS_DAS_NODE_REMOVE;
> +
> +	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
> +
> +	return 0;
> +}
> +
>  /*
>   * Note: If args->value is NULL the attribute will be removed, just
> like the
>   * Linux ->setattr API.
> @@ -812,29 +902,35 @@ xfs_attr_set(
>  	}
>  
>  	error = xfs_attr_lookup(args);
> -	if (args->value) {
> -		if (error == -EEXIST && (args->attr_flags &
> XATTR_CREATE))
> -			goto out_trans_cancel;
> -		if (error == -ENOATTR && (args->attr_flags &
> XATTR_REPLACE))
> -			goto out_trans_cancel;
> -		if (error != -ENOATTR && error != -EEXIST)
> +	switch (error) {
> +	case -EEXIST:
> +		/* if no value, we are performing a remove operation */
> +		if (!args->value) {
> +			error = xfs_attr_defer_remove(args);
> +			break;
> +		}
> +		/* Pure create fails if the attr already exists */
> +		if (args->attr_flags & XATTR_CREATE)
>  			goto out_trans_cancel;
>  
> -		error = xfs_attr_set_deferred(args);
> -		if (error)
> +		error = xfs_attr_defer_replace(args);
> +		break;
> +	case -ENOATTR:
> +		/* Can't remove what isn't there. */
> +		if (!args->value)
>  			goto out_trans_cancel;
>  
> -		/* shortform attribute has already been committed */
> -		if (!args->trans)
> -			goto out_unlock;
> -	} else {
> -		if (error != -EEXIST)
> +		/* Pure replace fails if no existing attr to replace.
> */
> +		if (args->attr_flags & XATTR_REPLACE)
>  			goto out_trans_cancel;
>  
> -		error = xfs_attr_remove_deferred(args);
> -		if (error)
> -			goto out_trans_cancel;
> +		error = xfs_attr_defer_add(args);
> +		break;
> +	default:
> +		goto out_trans_cancel;
>  	}
> +	if (error)
> +		goto out_trans_cancel;
>  
>  	/*
>  	 * If this is a synchronous mount, make sure that the
> @@ -898,72 +994,6 @@ xfs_attrd_destroy_cache(void)
>  	xfs_attrd_cache = NULL;
>  }
>  
> -STATIC int
> -xfs_attr_item_init(
> -	struct xfs_da_args	*args,
> -	unsigned int		op_flags,	/* op flag (set or
> remove) */
> -	struct xfs_attr_item	**attr)		/* new xfs_attr_item
> */
> -{
> -
> -	struct xfs_attr_item	*new;
> -
> -	new = kmem_zalloc(sizeof(struct xfs_attr_item), KM_NOFS);
> -	new->xattri_op_flags = op_flags;
> -	new->xattri_da_args = args;
> -
> -	*attr = new;
> -	return 0;
> -}
> -
> -/* Sets an attribute for an inode as a deferred operation */
> -int
> -xfs_attr_set_deferred(
> -	struct xfs_da_args	*args)
> -{
> -	struct xfs_attr_item	*new;
> -	int			error = 0;
> -
> -	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
> -	if (error)
> -		return error;
> -
> -	if (xfs_attr_is_shortform(args->dp))
> -		new->xattri_dela_state = XFS_DAS_SF_ADD;
> -	else if (xfs_attr_is_leaf(args->dp))
> -		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
> -	else
> -		new->xattri_dela_state = XFS_DAS_NODE_ADD;
> -
> -	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
> -
> -	return 0;
> -}
> -
> -/* Removes an attribute for an inode as a deferred operation */
> -int
> -xfs_attr_remove_deferred(
> -	struct xfs_da_args	*args)
> -{
> -
> -	struct xfs_attr_item	*new;
> -	int			error;
> -
> -	error  = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_REMOVE,
> &new);
> -	if (error)
> -		return error;
> -
> -	if (xfs_attr_is_shortform(args->dp))
> -		new->xattri_dela_state = XFS_DAS_SF_REMOVE;
> -	else if (xfs_attr_is_leaf(args->dp))
> -		new->xattri_dela_state = XFS_DAS_LEAF_REMOVE;
> -	else
> -		new->xattri_dela_state = XFS_DAS_NODE_REMOVE;
> -
> -	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
> -
> -	return 0;
> -}
> -
>  /*==================================================================
> ======
>   * External routines when attribute list is inside the inode
>  
> *====================================================================
> ====*/
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index e4b11ac243d7..cac7dfcf2dbe 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -559,8 +559,6 @@ bool xfs_attr_namecheck(const void *name, size_t
> length);
>  int xfs_attr_calc_size(struct xfs_da_args *args, int *local);
>  void xfs_init_attr_trans(struct xfs_da_args *args, struct
> xfs_trans_res *tres,
>  			 unsigned int *total);
> -int xfs_attr_set_deferred(struct xfs_da_args *args);
> -int xfs_attr_remove_deferred(struct xfs_da_args *args);
>  
>  extern struct kmem_cache	*xfs_attri_cache;
>  extern struct kmem_cache	*xfs_attrd_cache;

[PATCH 16/16] xfs: ATTR_REPLACE algorithm with LARP enabled needs rework

[Dave Chinner]

From: Dave Chinner <dchinner@redhat.com>

We can't use the same algorithm for replacing an existing attribute
when logging attributes. The existing algorithm is essentially:

1. create new attr w/ INCOMPLETE
2. atomically flip INCOMPLETE flags between old + new attribute
3. remove old attr which is marked w/ INCOMPLETE

This algorithm guarantees that we see either the old or new
attribute, and if we fail after the atomic flag flip, we don't have
to recover the removal of the old attr because we never see
INCOMPLETE attributes in lookups.

For logged attributes, however, this does not work. The logged
attribute intents do not track the work that has been done as the
transaction rolls, and hence the only recovery mechanism we have is
"run the replace operation from scratch".

This is further exacerbated by the attempt to avoid needing the
INCOMPLETE flag to create an atomic swap. This means we can create
a second active attribute of the same name before we remove the
original. If we fail at any point after the create but before the
removal has completed, we end up with duplicate attributes in
the attr btree and recovery only tries to replace one of them.

There are several other failure modes where we can leave partially
allocated remote attributes that expose stale data, partially free
remote attributes that enable UAF based stale data exposure, etc.

TO fix this, we need a different algorithm for replace operations
when LARP is enabled. Luckily, it's not that complex if we take the
right first step. That is, the first thing we log is the attri
intent with the new name/value pair and mark the old attr as
INCOMPLETE in the same transaction.

From there, we then remove the old attr and keep relogging the
new name/value in the intent, such that we always know that we have
to create the new attr in recovery. Once the old attr is removed,
we then run a normal ATTR_CREATE operation relogging the intent as
we go. If the new attr is local, then it gets created in a single
atomic transaction that also logs the final intent done. If the new
attr is remote, the we set INCOMPLETE on the new attr while we
allocate and set the remote value, and then we clear the INCOMPLETE
flag at in the last transaction taht logs the final intent done.

If we fail at any point in this algorithm, log recovery will always
see the same state on disk: the new name/value in the intent, and
either an INCOMPLETE attr or no attr in the attr btree. If we find
an INCOMPLETE attr, we run the full replace starting with removing
the INCOMPLETE attr. If we don't find it, then we simply create the
new attr.

Notably, recovery of a failed create that has an INCOMPLETE flag set
is now the same - we start with the lookup of the INCOMPLETE attr,
and if that exists then we do the full replace recovery process,
otherwise we just create the new attr.

Hence changing the way we do the replace operation when LARP is
enabled allows us to use the same log recovery algorithm for both
the ATTR_CREATE and ATTR_REPLACE operations. This is also the same
algorithm we use for runtime ATTR_REPLACE operations (except for the
step setting up the initial conditions).

The result is that:

- ATTR_CREATE uses the same algorithm regardless of whether LARP is
  enabled or not
- ATTR_REPLACE with larp=0 is identical to the old algorithm
- ATTR_REPLACE with larp=1 runs an unmodified attr removal algorithm
  from the larp=0 code and then runs the unmodified ATTR_CREATE
  code.
- log recovery when larp=1 runs the same ATTR_REPLACE algorithm as
  it uses at runtime.

Because the state machine is now quite clean, changing the algorithm
is really just a case of changing the initial state and how the
states link together for the ATTR_REPLACE case. Hence it's not a
huge amoutn of code for what is a fairly substantial rework
of the attr logging and recovery algorithm....

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c       | 137 ++++++++++++++-------------------
 fs/xfs/libxfs/xfs_attr.h       | 101 +++++++++++++++++++-----
 fs/xfs/libxfs/xfs_attr_leaf.c  |  22 ++++--
 fs/xfs/libxfs/xfs_da_btree.h   |   1 +
 fs/xfs/libxfs/xfs_defer.c      |   2 +
 fs/xfs/libxfs/xfs_log_format.h |   7 +-
 fs/xfs/xfs_acl.c               |   2 +-
 fs/xfs/xfs_attr_item.c         |  27 ++++++-
 fs/xfs/xfs_ioctl.c             |   2 +-
 fs/xfs/xfs_trace.h             |  10 +--
 fs/xfs/xfs_xattr.c             |   2 +-
 11 files changed, 197 insertions(+), 116 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 772506d44bfa..173144769ddc 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -260,19 +260,6 @@ xfs_attr_try_sf_addname(
 	return error;
 }
 
-/*
- * Check to see if the attr should be upgraded from non-existent or shortform to
- * single-leaf-block attribute list.
- */
-static inline bool
-xfs_attr_is_shortform(
-	struct xfs_inode    *ip)
-{
-	return ip->i_afp->if_format == XFS_DINODE_FMT_LOCAL ||
-	       (ip->i_afp->if_format == XFS_DINODE_FMT_EXTENTS &&
-		ip->i_afp->if_nextents == 0);
-}
-
 static int
 xfs_attr_sf_addname(
 	struct xfs_attr_item		*attr)
@@ -309,20 +296,29 @@ xfs_attr_sf_addname(
 }
 
 /*
- * When we bump the state to REPLACE, we may actually need to skip over the
- * state. When LARP mode is enabled, we don't need to run the atomic flags flip,
- * so we skip straight over the REPLACE state and go on to REMOVE_OLD.
+ * Handle the state change on completion of a multi-state attr operation.
+ *
+ * If the XFS_DA_OP_RENAME flag is set, this means the operation was the first
+ * modification in a attr replace operation and we still have to do the second
+ * state, indicated by @replace_state.
+ *
+ * We consume the XFS_DA_OP_RENAME flag so that when we are called again on
+ * completion of the second half of the attr replace operation we correctly
+ * signal that it is done.
  */
-static void
-xfs_attr_dela_state_set_replace(
+static enum xfs_delattr_state
+xfs_attr_complete_op(
 	struct xfs_attr_item	*attr,
-	enum xfs_delattr_state	replace)
+	enum xfs_delattr_state	replace_state)
 {
 	struct xfs_da_args	*args = attr->xattri_da_args;
+	bool			do_replace = args->op_flags & XFS_DA_OP_RENAME;
 
-	attr->xattri_dela_state = replace;
-	if (xfs_has_larp(args->dp->i_mount))
-		attr->xattri_dela_state++;
+	args->attr_flags &= ~XATTR_REPLACE;
+	args->op_flags &= ~XFS_DA_OP_RENAME;
+	if (do_replace)
+		return replace_state;
+	return XFS_DAS_DONE;
 }
 
 static int
@@ -364,10 +360,9 @@ xfs_attr_leaf_addname(
 	 */
 	if (args->rmtblkno)
 		attr->xattri_dela_state = XFS_DAS_LEAF_SET_RMT;
-	else if (args->op_flags & XFS_DA_OP_RENAME)
-		xfs_attr_dela_state_set_replace(attr, XFS_DAS_LEAF_REPLACE);
 	else
-		attr->xattri_dela_state = XFS_DAS_DONE;
+		attr->xattri_dela_state = xfs_attr_complete_op(attr,
+							XFS_DAS_LEAF_REPLACE);
 out:
 	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state, args->dp);
 	return error;
@@ -409,10 +404,9 @@ xfs_attr_node_addname(
 
 	if (args->rmtblkno)
 		attr->xattri_dela_state = XFS_DAS_NODE_SET_RMT;
-	else if (args->op_flags & XFS_DA_OP_RENAME)
-		xfs_attr_dela_state_set_replace(attr, XFS_DAS_NODE_REPLACE);
 	else
-		attr->xattri_dela_state = XFS_DAS_DONE;
+		attr->xattri_dela_state = xfs_attr_complete_op(attr,
+							XFS_DAS_NODE_REPLACE);
 out:
 	trace_xfs_attr_node_addname_return(attr->xattri_dela_state, args->dp);
 	return error;
@@ -442,18 +436,15 @@ xfs_attr_rmtval_alloc(
 	if (error)
 		return error;
 
-	/* If this is not a rename, clear the incomplete flag and we're done. */
-	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
+	attr->xattri_dela_state = xfs_attr_complete_op(attr,
+						++attr->xattri_dela_state);
+	/*
+	 * If we are not doing a rename, we've finished the operation but still
+	 * have to clear the incomplete flag protecting the new attr from
+	 * exposing partially initialised state if we crash during creation.
+	 */
+	if (attr->xattri_dela_state == XFS_DAS_DONE)
 		error = xfs_attr3_leaf_clearflag(args);
-		attr->xattri_dela_state = XFS_DAS_DONE;
-	} else {
-		/*
-		 * We are running a REPLACE operation, so we need to bump the
-		 * state to the step in that operation.
-		 */
-		attr->xattri_dela_state++;
-		xfs_attr_dela_state_set_replace(attr, attr->xattri_dela_state);
-	}
 out:
 	trace_xfs_attr_rmtval_alloc(attr->xattri_dela_state, args->dp);
 	return error;
@@ -578,11 +569,15 @@ xfs_attr_set_iter(
 		return xfs_attr_node_addname(attr);
 
 	case XFS_DAS_SF_REMOVE:
-		attr->xattri_dela_state = XFS_DAS_DONE;
-		return xfs_attr_sf_removename(args);
+		error = xfs_attr_sf_removename(args);
+		attr->xattri_dela_state = xfs_attr_complete_op(attr,
+						xfs_attr_init_add_state(args));
+		break;
 	case XFS_DAS_LEAF_REMOVE:
-		attr->xattri_dela_state = XFS_DAS_DONE;
-		return xfs_attr_leaf_removename(args);
+		error = xfs_attr_leaf_removename(args);
+		attr->xattri_dela_state = xfs_attr_complete_op(attr,
+						xfs_attr_init_add_state(args));
+		break;
 	case XFS_DAS_NODE_REMOVE:
 		error = xfs_attr_node_removename_setup(attr);
 		if (error)
@@ -678,12 +673,14 @@ xfs_attr_set_iter(
 
 	case XFS_DAS_LEAF_REMOVE_ATTR:
 		error = xfs_attr_leaf_remove_attr(attr);
-		attr->xattri_dela_state = XFS_DAS_DONE;
+		attr->xattri_dela_state = xfs_attr_complete_op(attr,
+						xfs_attr_init_add_state(args));
 		break;
 
 	case XFS_DAS_NODE_REMOVE_ATTR:
 		error = xfs_attr_node_remove_attr(attr);
-		attr->xattri_dela_state = XFS_DAS_DONE;
+		attr->xattri_dela_state = xfs_attr_complete_op(attr,
+						xfs_attr_init_add_state(args));
 		break;
 	default:
 		ASSERT(0);
@@ -753,14 +750,9 @@ xfs_attr_defer_add(
 	if (error)
 		return error;
 
-	if (xfs_attr_is_shortform(args->dp))
-		new->xattri_dela_state = XFS_DAS_SF_ADD;
-	else if (xfs_attr_is_leaf(args->dp))
-		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
-	else
-		new->xattri_dela_state = XFS_DAS_NODE_ADD;
-
+	new->xattri_dela_state = xfs_attr_init_add_state(args);
 	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
+	trace_xfs_attr_defer_add(new->xattri_dela_state, args->dp);
 
 	return 0;
 }
@@ -773,18 +765,13 @@ xfs_attr_defer_replace(
 	struct xfs_attr_item	*new;
 	int			error = 0;
 
-	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
+	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_REPLACE, &new);
 	if (error)
 		return error;
 
-	if (xfs_attr_is_shortform(args->dp))
-		new->xattri_dela_state = XFS_DAS_SF_ADD;
-	else if (xfs_attr_is_leaf(args->dp))
-		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
-	else
-		new->xattri_dela_state = XFS_DAS_NODE_ADD;
-
+	new->xattri_dela_state = xfs_attr_init_replace_state(args);
 	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
+	trace_xfs_attr_defer_replace(new->xattri_dela_state, args->dp);
 
 	return 0;
 }
@@ -802,14 +789,9 @@ xfs_attr_defer_remove(
 	if (error)
 		return error;
 
-	if (xfs_attr_is_shortform(args->dp))
-		new->xattri_dela_state = XFS_DAS_SF_REMOVE;
-	else if (xfs_attr_is_leaf(args->dp))
-		new->xattri_dela_state = XFS_DAS_LEAF_REMOVE;
-	else
-		new->xattri_dela_state = XFS_DAS_NODE_REMOVE;
-
+	new->xattri_dela_state = xfs_attr_init_remove_state(args);
 	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list);
+	trace_xfs_attr_defer_remove(new->xattri_dela_state, args->dp);
 
 	return 0;
 }
@@ -1032,6 +1014,7 @@ xfs_attr_shortform_addname(xfs_da_args_t *args)
 		 * not being around.
 		 */
 		args->attr_flags &= ~XATTR_REPLACE;
+		args->op_flags &= ~XFS_DA_OP_RENAME;
 	}
 
 	if (args->namelen >= XFS_ATTR_SF_ENTSIZE_MAX ||
@@ -1122,16 +1105,14 @@ xfs_attr_leaf_try_add(
 			goto out_brelse;
 
 		trace_xfs_attr_leaf_replace(args);
-
-		/* save the attribute state for later removal*/
-		args->op_flags |= XFS_DA_OP_RENAME;	/* an atomic rename */
-		xfs_attr_save_rmt_blk(args);
+		ASSERT(args->op_flags & XFS_DA_OP_RENAME);
 
 		/*
-		 * clear the remote attr state now that it is saved so that the
-		 * values reflect the state of the attribute we are about to
+		 * Save the existing remote attr state so that the current
+		 * values reflect the state of the new attribute we are about to
 		 * add, not the attribute we just found and will remove later.
 		 */
+		xfs_attr_save_rmt_blk(args);
 		args->rmtblkno = 0;
 		args->rmtblkcnt = 0;
 		args->rmtvaluelen = 0;
@@ -1293,16 +1274,14 @@ xfs_attr_node_addname_find_attr(
 			goto error;
 
 		trace_xfs_attr_node_replace(args);
-
-		/* save the attribute state for later removal*/
-		args->op_flags |= XFS_DA_OP_RENAME;	/* atomic rename op */
-		xfs_attr_save_rmt_blk(args);
+		ASSERT(args->op_flags & XFS_DA_OP_RENAME);
 
 		/*
-		 * clear the remote attr state now that it is saved so that the
-		 * values reflect the state of the attribute we are about to
+		 * Save the existing remote attr state so that the current
+		 * values reflect the state of the new attribute we are about to
 		 * add, not the attribute we just found and will remove later.
 		 */
+		xfs_attr_save_rmt_blk(args);
 		args->rmtblkno = 0;
 		args->rmtblkcnt = 0;
 		args->rmtvaluelen = 0;
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index cac7dfcf2dbe..49c89c49e7eb 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -444,18 +444,23 @@ struct xfs_attr_list_context {
  */
 enum xfs_delattr_state {
 	XFS_DAS_UNINIT		= 0,	/* No state has been set yet */
-	XFS_DAS_SF_ADD,			/* Initial shortform set iter state */
-	XFS_DAS_LEAF_ADD,		/* Initial leaf form set iter state */
-	XFS_DAS_NODE_ADD,		/* Initial node form set iter state */
-	XFS_DAS_RMTBLK,			/* Removing remote blks */
-	XFS_DAS_RM_NAME,		/* Remove attr name */
-	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree */
-
-	XFS_DAS_SF_REMOVE,		/* Initial shortform set iter state */
-	XFS_DAS_LEAF_REMOVE,		/* Initial leaf form set iter state */
-	XFS_DAS_NODE_REMOVE,		/* Initial node form set iter state */
-
-	/* Leaf state set/replace sequence */
+
+	/*
+	 * Initial sequence states. The replace setup code relies on the
+	 * ADD and REMOVE states for a specific format to be sequential so
+	 * that we can transform the initial operation to be performed
+	 * according to the xfs_has_larp() state easily.
+	 */
+	XFS_DAS_SF_ADD,			/* Initial sf add state */
+	XFS_DAS_SF_REMOVE,		/* Initial sf replace/remove state */
+
+	XFS_DAS_LEAF_ADD,		/* Initial leaf add state */
+	XFS_DAS_LEAF_REMOVE,		/* Initial leaf replace/remove state */
+
+	XFS_DAS_NODE_ADD,		/* Initial node add state */
+	XFS_DAS_NODE_REMOVE,		/* Initial node replace/remove state */
+
+	/* Leaf state set/replace/remove sequence */
 	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a leaf */
 	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a leaf */
@@ -463,7 +468,7 @@ enum xfs_delattr_state {
 	XFS_DAS_LEAF_REMOVE_RMT,	/* A rename is removing remote blocks */
 	XFS_DAS_LEAF_REMOVE_ATTR,	/* Remove the old attr from a leaf */
 
-	/* Node state set/replace sequence, must match leaf state above */
+	/* Node state sequence, must match leaf state above */
 	XFS_DAS_NODE_SET_RMT,		/* set a remote xattr from a node */
 	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote blocks */
 	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a node */
@@ -477,11 +482,11 @@ enum xfs_delattr_state {
 #define XFS_DAS_STRINGS	\
 	{ XFS_DAS_UNINIT,		"XFS_DAS_UNINIT" }, \
 	{ XFS_DAS_SF_ADD,		"XFS_DAS_SF_ADD" }, \
+	{ XFS_DAS_SF_REMOVE,		"XFS_DAS_SF_REMOVE" }, \
 	{ XFS_DAS_LEAF_ADD,		"XFS_DAS_LEAF_ADD" }, \
+	{ XFS_DAS_LEAF_REMOVE,		"XFS_DAS_LEAF_REMOVE" }, \
 	{ XFS_DAS_NODE_ADD,		"XFS_DAS_NODE_ADD" }, \
-	{ XFS_DAS_RMTBLK,		"XFS_DAS_RMTBLK" }, \
-	{ XFS_DAS_RM_NAME,		"XFS_DAS_RM_NAME" }, \
-	{ XFS_DAS_RM_SHRINK,		"XFS_DAS_RM_SHRINK" }, \
+	{ XFS_DAS_NODE_REMOVE,		"XFS_DAS_NODE_REMOVE" }, \
 	{ XFS_DAS_LEAF_SET_RMT,		"XFS_DAS_LEAF_SET_RMT" }, \
 	{ XFS_DAS_LEAF_ALLOC_RMT,	"XFS_DAS_LEAF_ALLOC_RMT" }, \
 	{ XFS_DAS_LEAF_REPLACE,		"XFS_DAS_LEAF_REPLACE" }, \
@@ -525,8 +530,7 @@ struct xfs_attr_item {
 	enum xfs_delattr_state		xattri_dela_state;
 
 	/*
-	 * Indicates if the attr operation is a set or a remove
-	 * XFS_ATTR_OP_FLAGS_{SET,REMOVE}
+	 * Attr operation being performed - XFS_ATTR_OP_FLAGS_*
 	 */
 	unsigned int			xattri_op_flags;
 
@@ -568,4 +572,65 @@ void xfs_attri_destroy_cache(void);
 int __init xfs_attrd_init_cache(void);
 void xfs_attrd_destroy_cache(void);
 
+/*
+ * Check to see if the attr should be upgraded from non-existent or shortform to
+ * single-leaf-block attribute list.
+ */
+static inline bool
+xfs_attr_is_shortform(
+	struct xfs_inode    *ip)
+{
+	return ip->i_afp->if_format == XFS_DINODE_FMT_LOCAL ||
+	       (ip->i_afp->if_format == XFS_DINODE_FMT_EXTENTS &&
+		ip->i_afp->if_nextents == 0);
+}
+
+static inline enum xfs_delattr_state
+xfs_attr_init_add_state(struct xfs_da_args *args)
+{
+	/*
+	 * On a pure remove, we can remove the attr fork so when we are
+	 * called to set the add state after the remove to set up the next
+	 * replace state, we can hit this case here. However, we will not see
+	 * an empty fork on logged replace operation, so if there is no attr
+	 * fork then we are done here.
+	 *
+	 * XXX: The replace state changeover needs a bit of rework to
+	 * avoid this quirk.
+	 */
+	if (!args->dp->i_afp)
+		return XFS_DAS_DONE;
+	if (xfs_attr_is_shortform(args->dp))
+		return XFS_DAS_SF_ADD;
+	if (xfs_attr_is_leaf(args->dp))
+		return XFS_DAS_LEAF_ADD;
+	return XFS_DAS_NODE_ADD;
+}
+
+static inline enum xfs_delattr_state
+xfs_attr_init_remove_state(struct xfs_da_args *args)
+{
+	if (xfs_attr_is_shortform(args->dp))
+		return XFS_DAS_SF_REMOVE;
+	if (xfs_attr_is_leaf(args->dp))
+		return XFS_DAS_LEAF_REMOVE;
+	return XFS_DAS_NODE_REMOVE;
+}
+
+/*
+ * If we are logging the attributes, then we have to start with removal of the
+ * old attribute so that there is always consistent state that we can recover
+ * from if the system goes down part way through. We always log the new attr
+ * value, so even when we remove the attr first we still have the information in
+ * the log to finish the replace operation atomically.
+ */
+static inline enum xfs_delattr_state
+xfs_attr_init_replace_state(struct xfs_da_args *args)
+{
+	args->op_flags |= XFS_DA_OP_RENAME;
+	if (xfs_has_larp(args->dp->i_mount))
+		return xfs_attr_init_remove_state(args);
+	return xfs_attr_init_add_state(args);
+}
+
 #endif	/* __XFS_ATTR_H__ */
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index e90bfd9d7551..ff5ed9319270 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -446,6 +446,14 @@ xfs_attr3_leaf_read(
  * Namespace helper routines
  *========================================================================*/
 
+/*
+ * If we are in log recovery, then we want the lookup to ignore the INCOMPLETE
+ * flag on disk - if there's an incomplete attr then recovery needs to tear it
+ * down. If there's no incomplete attr, then recovery needs to tear that attr
+ * down to replace it with the attr that has been logged. In this case, the
+ * INCOMPLETE flag will not be set in attr->attr_filter, but rather
+ * XFS_DA_OP_RECOVERY will be set in args->op_flags.
+ */
 static bool
 xfs_attr_match(
 	struct xfs_da_args	*args,
@@ -453,14 +461,18 @@ xfs_attr_match(
 	unsigned char		*name,
 	int			flags)
 {
+
 	if (args->namelen != namelen)
 		return false;
 	if (memcmp(args->name, name, namelen) != 0)
 		return false;
-	/*
-	 * If we are looking for incomplete entries, show only those, else only
-	 * show complete entries.
-	 */
+
+	/* Recovery ignores the INCOMPLETE flag. */
+	if ((args->op_flags & XFS_DA_OP_RECOVERY) &&
+	    args->attr_filter == (flags & XFS_ATTR_NSP_ONDISK_MASK))
+		return true;
+
+	/* All remaining matches need to be filtered by INCOMPLETE state. */
 	if (args->attr_filter !=
 	    (flags & (XFS_ATTR_NSP_ONDISK_MASK | XFS_ATTR_INCOMPLETE)))
 		return false;
@@ -819,7 +831,7 @@ xfs_attr_sf_removename(
 	totsize -= size;
 	if (totsize == sizeof(xfs_attr_sf_hdr_t) && xfs_has_attr2(mp) &&
 	    (dp->i_df.if_format != XFS_DINODE_FMT_BTREE) &&
-	    !(args->op_flags & XFS_DA_OP_ADDNAME)) {
+	    !(args->op_flags & (XFS_DA_OP_ADDNAME | XFS_DA_OP_RENAME))) {
 		xfs_attr_fork_remove(dp, args->trans);
 	} else {
 		xfs_idata_realloc(dp, -size, XFS_ATTR_FORK);
diff --git a/fs/xfs/libxfs/xfs_da_btree.h b/fs/xfs/libxfs/xfs_da_btree.h
index deb368d041e3..ca207d11bf66 100644
--- a/fs/xfs/libxfs/xfs_da_btree.h
+++ b/fs/xfs/libxfs/xfs_da_btree.h
@@ -90,6 +90,7 @@ typedef struct xfs_da_args {
 #define XFS_DA_OP_OKNOENT	(1u << 3) /* lookup op, ENOENT ok, else die */
 #define XFS_DA_OP_CILOOKUP	(1u << 4) /* lookup returns CI name if found */
 #define XFS_DA_OP_NOTIME	(1u << 5) /* don't update inode timestamps */
+#define XFS_DA_OP_RECOVERY	(1u << 6) /* running a recovery operation */
 
 #define XFS_DA_OP_FLAGS \
 	{ XFS_DA_OP_JUSTCHECK,	"JUSTCHECK" }, \
diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
index cac921ac18a8..991dee79c29c 100644
--- a/fs/xfs/libxfs/xfs_defer.c
+++ b/fs/xfs/libxfs/xfs_defer.c
@@ -23,6 +23,8 @@
 #include "xfs_bmap.h"
 #include "xfs_alloc.h"
 #include "xfs_buf.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
 #include "xfs_attr.h"
 
 static struct kmem_cache	*xfs_defer_pending_cache;
diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
index a27492e99673..e430f294c747 100644
--- a/fs/xfs/libxfs/xfs_log_format.h
+++ b/fs/xfs/libxfs/xfs_log_format.h
@@ -906,9 +906,10 @@ struct xfs_icreate_log {
  * Flags for deferred attribute operations.
  * Upper bits are flags, lower byte is type code
  */
-#define XFS_ATTR_OP_FLAGS_SET		1	/* Set the attribute */
-#define XFS_ATTR_OP_FLAGS_REMOVE	2	/* Remove the attribute */
-#define XFS_ATTR_OP_FLAGS_TYPE_MASK	0xFF	/* Flags type mask */
+#define XFS_ATTR_OP_FLAGS_SET		(1u << 0) /* Set the attribute */
+#define XFS_ATTR_OP_FLAGS_REMOVE	(1u << 1) /* Remove the attribute */
+#define XFS_ATTR_OP_FLAGS_REPLACE	(1u << 2) /* Replace the attribute */
+#define XFS_ATTR_OP_FLAGS_TYPE_MASK	0xFF	  /* Flags type mask */
 
 /*
  * This is the structure used to lay out an attr log item in the
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 5c52ee869272..df3059490af9 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -10,12 +10,12 @@
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_inode.h"
-#include "xfs_attr.h"
 #include "xfs_trace.h"
 #include "xfs_error.h"
 #include "xfs_acl.h"
 #include "xfs_da_format.h"
 #include "xfs_da_btree.h"
+#include "xfs_attr.h"
 #include "xfs_trans.h"
 
 #include <linux/posix_acl_xattr.h>
diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
index 39af681897a2..a46379a9e9df 100644
--- a/fs/xfs/xfs_attr_item.c
+++ b/fs/xfs/xfs_attr_item.c
@@ -490,9 +490,14 @@ xfs_attri_validate(
 	if (attrp->__pad != 0)
 		return false;
 
-	/* alfi_op_flags should be either a set or remove */
-	if (op != XFS_ATTR_OP_FLAGS_SET && op != XFS_ATTR_OP_FLAGS_REMOVE)
+	switch (op) {
+	case XFS_ATTR_OP_FLAGS_SET:
+	case XFS_ATTR_OP_FLAGS_REMOVE:
+	case XFS_ATTR_OP_FLAGS_REPLACE:
+		break;
+	default:
 		return false;
+	}
 
 	if (attrp->alfi_value_len > XATTR_SIZE_MAX)
 		return false;
@@ -553,11 +558,27 @@ xfs_attri_item_recover(
 	args->namelen = attrp->alfi_name_len;
 	args->hashval = xfs_da_hashname(args->name, args->namelen);
 	args->attr_filter = attrp->alfi_attr_flags;
+	args->op_flags = XFS_DA_OP_RECOVERY;
 
-	if (attrp->alfi_op_flags == XFS_ATTR_OP_FLAGS_SET) {
+	switch (attr->xattri_op_flags) {
+	case XFS_ATTR_OP_FLAGS_SET:
+	case XFS_ATTR_OP_FLAGS_REPLACE:
 		args->value = attrip->attri_value;
 		args->valuelen = attrp->alfi_value_len;
 		args->total = xfs_attr_calc_size(args, &local);
+		if (xfs_inode_hasattr(args->dp))
+			attr->xattri_dela_state = xfs_attr_init_replace_state(args);
+		else
+			attr->xattri_dela_state = xfs_attr_init_add_state(args);
+		break;
+	case XFS_ATTR_OP_FLAGS_REMOVE:
+		if (!xfs_inode_hasattr(args->dp))
+			goto out;
+		attr->xattri_dela_state = xfs_attr_init_remove_state(args);
+		break;
+	default:
+		error = -EFSCORRUPTED;
+		goto out;
 	}
 
 	xfs_init_attr_trans(args, &tres, &total);
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index e9eadc7337ce..64254895d083 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -15,7 +15,6 @@
 #include "xfs_iwalk.h"
 #include "xfs_itable.h"
 #include "xfs_error.h"
-#include "xfs_attr.h"
 #include "xfs_bmap.h"
 #include "xfs_bmap_util.h"
 #include "xfs_fsops.h"
@@ -37,6 +36,7 @@
 #include "xfs_ioctl.h"
 #include "xfs_da_format.h"
 #include "xfs_da_btree.h"
+#include "xfs_attr.h"
 
 #include <linux/mount.h>
 #include <linux/namei.h>
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index c85bab6215e1..8783aeb096c4 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -4100,13 +4100,10 @@ DEFINE_ICLOG_EVENT(xlog_iclog_write);
 
 TRACE_DEFINE_ENUM(XFS_DAS_UNINIT);
 TRACE_DEFINE_ENUM(XFS_DAS_SF_ADD);
-TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ADD);
-TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
-TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
-TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
-TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
 TRACE_DEFINE_ENUM(XFS_DAS_SF_REMOVE);
+TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ADD);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE);
+TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
 TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
 TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
@@ -4142,6 +4139,9 @@ DECLARE_EVENT_CLASS(xfs_das_state_class,
 DEFINE_EVENT(xfs_das_state_class, name, \
 	TP_PROTO(int das, struct xfs_inode *ip), \
 	TP_ARGS(das, ip))
+DEFINE_DAS_STATE_EVENT(xfs_attr_defer_add);
+DEFINE_DAS_STATE_EVENT(xfs_attr_defer_replace);
+DEFINE_DAS_STATE_EVENT(xfs_attr_defer_remove);
 DEFINE_DAS_STATE_EVENT(xfs_attr_sf_addname_return);
 DEFINE_DAS_STATE_EVENT(xfs_attr_set_iter_return);
 DEFINE_DAS_STATE_EVENT(xfs_attr_leaf_addname_return);
diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
index 0d050f8829ef..6935edcaa112 100644
--- a/fs/xfs/xfs_xattr.c
+++ b/fs/xfs/xfs_xattr.c
@@ -12,9 +12,9 @@
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_inode.h"
-#include "xfs_attr.h"
 #include "xfs_acl.h"
 #include "xfs_da_btree.h"
+#include "xfs_attr.h"
 
 #include <linux/posix_acl_xattr.h>
 
-- 
2.35.1

Re: [PATCH 16/16] xfs: ATTR_REPLACE algorithm with LARP enabled needs rework

[Alli]

On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> We can't use the same algorithm for replacing an existing attribute
> when logging attributes. The existing algorithm is essentially:
> 
> 1. create new attr w/ INCOMPLETE
> 2. atomically flip INCOMPLETE flags between old + new attribute
> 3. remove old attr which is marked w/ INCOMPLETE
> 
> This algorithm guarantees that we see either the old or new
> attribute, and if we fail after the atomic flag flip, we don't have
> to recover the removal of the old attr because we never see
> INCOMPLETE attributes in lookups.
> 
> For logged attributes, however, this does not work. The logged
> attribute intents do not track the work that has been done as the
> transaction rolls, and hence the only recovery mechanism we have is
> "run the replace operation from scratch".
> 
> This is further exacerbated by the attempt to avoid needing the
> INCOMPLETE flag to create an atomic swap. This means we can create
> a second active attribute of the same name before we remove the
> original. If we fail at any point after the create but before the
> removal has completed, we end up with duplicate attributes in
> the attr btree and recovery only tries to replace one of them.
> 
> There are several other failure modes where we can leave partially
> allocated remote attributes that expose stale data, partially free
> remote attributes that enable UAF based stale data exposure, etc.
> 
> TO fix this, we need a different algorithm for replace operations
> when LARP is enabled. Luckily, it's not that complex if we take the
> right first step. That is, the first thing we log is the attri
> intent with the new name/value pair and mark the old attr as
> INCOMPLETE in the same transaction.
> 
> From there, we then remove the old attr and keep relogging the
> new name/value in the intent, such that we always know that we have
> to create the new attr in recovery. Once the old attr is removed,
> we then run a normal ATTR_CREATE operation relogging the intent as
> we go. If the new attr is local, then it gets created in a single
> atomic transaction that also logs the final intent done. If the new
> attr is remote, the we set INCOMPLETE on the new attr while we
> allocate and set the remote value, and then we clear the INCOMPLETE
> flag at in the last transaction taht logs the final intent done.
> 
> If we fail at any point in this algorithm, log recovery will always
> see the same state on disk: the new name/value in the intent, and
> either an INCOMPLETE attr or no attr in the attr btree. If we find
> an INCOMPLETE attr, we run the full replace starting with removing
> the INCOMPLETE attr. If we don't find it, then we simply create the
> new attr.
> 
> Notably, recovery of a failed create that has an INCOMPLETE flag set
> is now the same - we start with the lookup of the INCOMPLETE attr,
> and if that exists then we do the full replace recovery process,
> otherwise we just create the new attr.
> 
> Hence changing the way we do the replace operation when LARP is
> enabled allows us to use the same log recovery algorithm for both
> the ATTR_CREATE and ATTR_REPLACE operations. This is also the same
> algorithm we use for runtime ATTR_REPLACE operations (except for the
> step setting up the initial conditions).
> 
> The result is that:
> 
> - ATTR_CREATE uses the same algorithm regardless of whether LARP is
>   enabled or not
> - ATTR_REPLACE with larp=0 is identical to the old algorithm
> - ATTR_REPLACE with larp=1 runs an unmodified attr removal algorithm
>   from the larp=0 code and then runs the unmodified ATTR_CREATE
>   code.
> - log recovery when larp=1 runs the same ATTR_REPLACE algorithm as
>   it uses at runtime.
> 
> Because the state machine is now quite clean, changing the algorithm
> is really just a case of changing the initial state and how the
> states link together for the ATTR_REPLACE case. Hence it's not a
> huge amoutn of code for what is a fairly substantial rework
> of the attr logging and recovery algorithm....
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Ok, I think I was able to follow most of this through.  I think it
looks mostly good, I did catch one buggly down below....

> ---
>  fs/xfs/libxfs/xfs_attr.c       | 137 ++++++++++++++-----------------
> --
>  fs/xfs/libxfs/xfs_attr.h       | 101 +++++++++++++++++++-----
>  fs/xfs/libxfs/xfs_attr_leaf.c  |  22 ++++--
>  fs/xfs/libxfs/xfs_da_btree.h   |   1 +
>  fs/xfs/libxfs/xfs_defer.c      |   2 +
>  fs/xfs/libxfs/xfs_log_format.h |   7 +-
>  fs/xfs/xfs_acl.c               |   2 +-
>  fs/xfs/xfs_attr_item.c         |  27 ++++++-
>  fs/xfs/xfs_ioctl.c             |   2 +-
>  fs/xfs/xfs_trace.h             |  10 +--
>  fs/xfs/xfs_xattr.c             |   2 +-
>  11 files changed, 197 insertions(+), 116 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> index 772506d44bfa..173144769ddc 100644
> --- a/fs/xfs/libxfs/xfs_attr.c
> +++ b/fs/xfs/libxfs/xfs_attr.c
> @@ -260,19 +260,6 @@ xfs_attr_try_sf_addname(
>  	return error;
>  }
>  
> -/*
> - * Check to see if the attr should be upgraded from non-existent or
> shortform to
> - * single-leaf-block attribute list.
> - */
> -static inline bool
> -xfs_attr_is_shortform(
> -	struct xfs_inode    *ip)
> -{
> -	return ip->i_afp->if_format == XFS_DINODE_FMT_LOCAL ||
> -	       (ip->i_afp->if_format == XFS_DINODE_FMT_EXTENTS &&
> -		ip->i_afp->if_nextents == 0);
> -}
> -
>  static int
>  xfs_attr_sf_addname(
>  	struct xfs_attr_item		*attr)
> @@ -309,20 +296,29 @@ xfs_attr_sf_addname(
>  }
>  
>  /*
> - * When we bump the state to REPLACE, we may actually need to skip
> over the
> - * state. When LARP mode is enabled, we don't need to run the atomic
> flags flip,
> - * so we skip straight over the REPLACE state and go on to
> REMOVE_OLD.
> + * Handle the state change on completion of a multi-state attr
> operation.
> + *
> + * If the XFS_DA_OP_RENAME flag is set, this means the operation was
> the first
> + * modification in a attr replace operation and we still have to do
> the second
> + * state, indicated by @replace_state.
> + *
> + * We consume the XFS_DA_OP_RENAME flag so that when we are called
> again on
> + * completion of the second half of the attr replace operation we
> correctly
> + * signal that it is done.
>   */
> -static void
> -xfs_attr_dela_state_set_replace(
> +static enum xfs_delattr_state
> +xfs_attr_complete_op(
>  	struct xfs_attr_item	*attr,
> -	enum xfs_delattr_state	replace)
> +	enum xfs_delattr_state	replace_state)
>  {
>  	struct xfs_da_args	*args = attr->xattri_da_args;
> +	bool			do_replace = args->op_flags &
> XFS_DA_OP_RENAME;
>  
> -	attr->xattri_dela_state = replace;
> -	if (xfs_has_larp(args->dp->i_mount))
> -		attr->xattri_dela_state++;
> +	args->attr_flags &= ~XATTR_REPLACE;
> +	args->op_flags &= ~XFS_DA_OP_RENAME;
> +	if (do_replace)
> +		return replace_state;
> +	return XFS_DAS_DONE;
>  }
>  
>  static int
> @@ -364,10 +360,9 @@ xfs_attr_leaf_addname(
>  	 */
>  	if (args->rmtblkno)
>  		attr->xattri_dela_state = XFS_DAS_LEAF_SET_RMT;
> -	else if (args->op_flags & XFS_DA_OP_RENAME)
> -		xfs_attr_dela_state_set_replace(attr,
> XFS_DAS_LEAF_REPLACE);
>  	else
> -		attr->xattri_dela_state = XFS_DAS_DONE;
> +		attr->xattri_dela_state = xfs_attr_complete_op(attr,
> +							XFS_DAS_LEAF_RE
> PLACE);
>  out:
>  	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state,
> args->dp);
>  	return error;
> @@ -409,10 +404,9 @@ xfs_attr_node_addname(
>  
>  	if (args->rmtblkno)
>  		attr->xattri_dela_state = XFS_DAS_NODE_SET_RMT;
> -	else if (args->op_flags & XFS_DA_OP_RENAME)
> -		xfs_attr_dela_state_set_replace(attr,
> XFS_DAS_NODE_REPLACE);
>  	else
> -		attr->xattri_dela_state = XFS_DAS_DONE;
> +		attr->xattri_dela_state = xfs_attr_complete_op(attr,
> +							XFS_DAS_NODE_RE
> PLACE);
>  out:
>  	trace_xfs_attr_node_addname_return(attr->xattri_dela_state,
> args->dp);
>  	return error;
> @@ -442,18 +436,15 @@ xfs_attr_rmtval_alloc(
>  	if (error)
>  		return error;
>  
> -	/* If this is not a rename, clear the incomplete flag and we're
> done. */
> -	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
> +	attr->xattri_dela_state = xfs_attr_complete_op(attr,
> +						++attr-
> >xattri_dela_state);
> +	/*
> +	 * If we are not doing a rename, we've finished the operation
> but still
> +	 * have to clear the incomplete flag protecting the new attr
> from
> +	 * exposing partially initialised state if we crash during
> creation.
> +	 */
> +	if (attr->xattri_dela_state == XFS_DAS_DONE)
>  		error = xfs_attr3_leaf_clearflag(args);
> -		attr->xattri_dela_state = XFS_DAS_DONE;
> -	} else {
> -		/*
> -		 * We are running a REPLACE operation, so we need to
> bump the
> -		 * state to the step in that operation.
> -		 */
> -		attr->xattri_dela_state++;
> -		xfs_attr_dela_state_set_replace(attr, attr-
> >xattri_dela_state);
> -	}
>  out:
>  	trace_xfs_attr_rmtval_alloc(attr->xattri_dela_state, args->dp);
>  	return error;
> @@ -578,11 +569,15 @@ xfs_attr_set_iter(
>  		return xfs_attr_node_addname(attr);
>  
>  	case XFS_DAS_SF_REMOVE:
> -		attr->xattri_dela_state = XFS_DAS_DONE;
> -		return xfs_attr_sf_removename(args);
> +		error = xfs_attr_sf_removename(args);
> +		attr->xattri_dela_state = xfs_attr_complete_op(attr,
> +						xfs_attr_init_add_state
> (args));
> +		break;
>  	case XFS_DAS_LEAF_REMOVE:
> -		attr->xattri_dela_state = XFS_DAS_DONE;
> -		return xfs_attr_leaf_removename(args);
> +		error = xfs_attr_leaf_removename(args);
> +		attr->xattri_dela_state = xfs_attr_complete_op(attr,
> +						xfs_attr_init_add_state
> (args));
> +		break;
>  	case XFS_DAS_NODE_REMOVE:
>  		error = xfs_attr_node_removename_setup(attr);
>  		if (error)
> @@ -678,12 +673,14 @@ xfs_attr_set_iter(
>  
>  	case XFS_DAS_LEAF_REMOVE_ATTR:
>  		error = xfs_attr_leaf_remove_attr(attr);
> -		attr->xattri_dela_state = XFS_DAS_DONE;
> +		attr->xattri_dela_state = xfs_attr_complete_op(attr,
> +						xfs_attr_init_add_state
> (args));
>  		break;
>  
>  	case XFS_DAS_NODE_REMOVE_ATTR:
>  		error = xfs_attr_node_remove_attr(attr);
> -		attr->xattri_dela_state = XFS_DAS_DONE;
> +		attr->xattri_dela_state = xfs_attr_complete_op(attr,
> +						xfs_attr_init_add_state
> (args));
>  		break;
>  	default:
>  		ASSERT(0);
> @@ -753,14 +750,9 @@ xfs_attr_defer_add(
>  	if (error)
>  		return error;
>  
> -	if (xfs_attr_is_shortform(args->dp))
> -		new->xattri_dela_state = XFS_DAS_SF_ADD;
> -	else if (xfs_attr_is_leaf(args->dp))
> -		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
> -	else
> -		new->xattri_dela_state = XFS_DAS_NODE_ADD;
> -
> +	new->xattri_dela_state = xfs_attr_init_add_state(args);
>  	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
> +	trace_xfs_attr_defer_add(new->xattri_dela_state, args->dp);
>  
>  	return 0;
>  }
> @@ -773,18 +765,13 @@ xfs_attr_defer_replace(
>  	struct xfs_attr_item	*new;
>  	int			error = 0;
>  
> -	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new);
> +	error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_REPLACE,
> &new);
>  	if (error)
>  		return error;
>  
> -	if (xfs_attr_is_shortform(args->dp))
> -		new->xattri_dela_state = XFS_DAS_SF_ADD;
> -	else if (xfs_attr_is_leaf(args->dp))
> -		new->xattri_dela_state = XFS_DAS_LEAF_ADD;
> -	else
> -		new->xattri_dela_state = XFS_DAS_NODE_ADD;
> -
> +	new->xattri_dela_state = xfs_attr_init_replace_state(args);
>  	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
> +	trace_xfs_attr_defer_replace(new->xattri_dela_state, args->dp);
>  
>  	return 0;
>  }
> @@ -802,14 +789,9 @@ xfs_attr_defer_remove(
>  	if (error)
>  		return error;
>  
> -	if (xfs_attr_is_shortform(args->dp))
> -		new->xattri_dela_state = XFS_DAS_SF_REMOVE;
> -	else if (xfs_attr_is_leaf(args->dp))
> -		new->xattri_dela_state = XFS_DAS_LEAF_REMOVE;
> -	else
> -		new->xattri_dela_state = XFS_DAS_NODE_REMOVE;
> -
> +	new->xattri_dela_state = xfs_attr_init_remove_state(args);
>  	xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new-
> >xattri_list);
> +	trace_xfs_attr_defer_remove(new->xattri_dela_state, args->dp);
>  
>  	return 0;
>  }
> @@ -1032,6 +1014,7 @@ xfs_attr_shortform_addname(xfs_da_args_t *args)
>  		 * not being around.
>  		 */
>  		args->attr_flags &= ~XATTR_REPLACE;
> +		args->op_flags &= ~XFS_DA_OP_RENAME;
>  	}
>  
>  	if (args->namelen >= XFS_ATTR_SF_ENTSIZE_MAX ||
> @@ -1122,16 +1105,14 @@ xfs_attr_leaf_try_add(
>  			goto out_brelse;
>  
>  		trace_xfs_attr_leaf_replace(args);
> -
> -		/* save the attribute state for later removal*/
> -		args->op_flags |= XFS_DA_OP_RENAME;	/* an atomic
> rename */
> -		xfs_attr_save_rmt_blk(args);
> +		ASSERT(args->op_flags & XFS_DA_OP_RENAME);
>  
>  		/*
> -		 * clear the remote attr state now that it is saved so
> that the
> -		 * values reflect the state of the attribute we are
> about to
> +		 * Save the existing remote attr state so that the
> current
> +		 * values reflect the state of the new attribute we are
> about to
>  		 * add, not the attribute we just found and will remove
> later.
>  		 */
> +		xfs_attr_save_rmt_blk(args);
>  		args->rmtblkno = 0;
>  		args->rmtblkcnt = 0;
>  		args->rmtvaluelen = 0;
> @@ -1293,16 +1274,14 @@ xfs_attr_node_addname_find_attr(
>  			goto error;
>  
>  		trace_xfs_attr_node_replace(args);
> -
> -		/* save the attribute state for later removal*/
> -		args->op_flags |= XFS_DA_OP_RENAME;	/* atomic
> rename op */
> -		xfs_attr_save_rmt_blk(args);
> +		ASSERT(args->op_flags & XFS_DA_OP_RENAME);
>  
>  		/*
> -		 * clear the remote attr state now that it is saved so
> that the
> -		 * values reflect the state of the attribute we are
> about to
> +		 * Save the existing remote attr state so that the
> current
> +		 * values reflect the state of the new attribute we are
> about to
>  		 * add, not the attribute we just found and will remove
> later.
>  		 */
> +		xfs_attr_save_rmt_blk(args);
>  		args->rmtblkno = 0;
>  		args->rmtblkcnt = 0;
>  		args->rmtvaluelen = 0;
> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> index cac7dfcf2dbe..49c89c49e7eb 100644
> --- a/fs/xfs/libxfs/xfs_attr.h
> +++ b/fs/xfs/libxfs/xfs_attr.h
> @@ -444,18 +444,23 @@ struct xfs_attr_list_context {
>   */
>  enum xfs_delattr_state {
>  	XFS_DAS_UNINIT		= 0,	/* No state has been set yet
> */
> -	XFS_DAS_SF_ADD,			/* Initial shortform set iter
> state */
> -	XFS_DAS_LEAF_ADD,		/* Initial leaf form set iter state
> */
> -	XFS_DAS_NODE_ADD,		/* Initial node form set iter state
> */
> -	XFS_DAS_RMTBLK,			/* Removing remote blks */
> -	XFS_DAS_RM_NAME,		/* Remove attr name */
> -	XFS_DAS_RM_SHRINK,		/* We are shrinking the tree
> */
> -
> -	XFS_DAS_SF_REMOVE,		/* Initial shortform set iter
> state */
> -	XFS_DAS_LEAF_REMOVE,		/* Initial leaf form set iter
> state */
> -	XFS_DAS_NODE_REMOVE,		/* Initial node form set iter
> state */
> -
> -	/* Leaf state set/replace sequence */
> +
> +	/*
> +	 * Initial sequence states. The replace setup code relies on
> the
> +	 * ADD and REMOVE states for a specific format to be sequential
> so
> +	 * that we can transform the initial operation to be performed
> +	 * according to the xfs_has_larp() state easily.
> +	 */
> +	XFS_DAS_SF_ADD,			/* Initial sf add state */
> +	XFS_DAS_SF_REMOVE,		/* Initial sf replace/remove
> state */
> +
> +	XFS_DAS_LEAF_ADD,		/* Initial leaf add state */
> +	XFS_DAS_LEAF_REMOVE,		/* Initial leaf
> replace/remove state */
> +
> +	XFS_DAS_NODE_ADD,		/* Initial node add state */
> +	XFS_DAS_NODE_REMOVE,		/* Initial node
> replace/remove state */
> +
> +	/* Leaf state set/replace/remove sequence */
>  	XFS_DAS_LEAF_SET_RMT,		/* set a remote xattr from a
> leaf */
>  	XFS_DAS_LEAF_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_LEAF_REPLACE,		/* Perform replace ops on a
> leaf */
> @@ -463,7 +468,7 @@ enum xfs_delattr_state {
>  	XFS_DAS_LEAF_REMOVE_RMT,	/* A rename is removing remote blocks
> */
>  	XFS_DAS_LEAF_REMOVE_ATTR,	/* Remove the old attr from a leaf */
>  
> -	/* Node state set/replace sequence, must match leaf state above
> */
> +	/* Node state sequence, must match leaf state above */
>  	XFS_DAS_NODE_SET_RMT,		/* set a remote xattr from a
> node */
>  	XFS_DAS_NODE_ALLOC_RMT,		/* We are allocating remote
> blocks */
>  	XFS_DAS_NODE_REPLACE,		/* Perform replace ops on a
> node */
> @@ -477,11 +482,11 @@ enum xfs_delattr_state {
>  #define XFS_DAS_STRINGS	\
>  	{ XFS_DAS_UNINIT,		"XFS_DAS_UNINIT" }, \
>  	{ XFS_DAS_SF_ADD,		"XFS_DAS_SF_ADD" }, \
> +	{ XFS_DAS_SF_REMOVE,		"XFS_DAS_SF_REMOVE" }, \
>  	{ XFS_DAS_LEAF_ADD,		"XFS_DAS_LEAF_ADD" }, \
> +	{ XFS_DAS_LEAF_REMOVE,		"XFS_DAS_LEAF_REMOVE" }, \
>  	{ XFS_DAS_NODE_ADD,		"XFS_DAS_NODE_ADD" }, \
> -	{ XFS_DAS_RMTBLK,		"XFS_DAS_RMTBLK" }, \
> -	{ XFS_DAS_RM_NAME,		"XFS_DAS_RM_NAME" }, \
> -	{ XFS_DAS_RM_SHRINK,		"XFS_DAS_RM_SHRINK" }, \
> +	{ XFS_DAS_NODE_REMOVE,		"XFS_DAS_NODE_REMOVE" }, \
>  	{ XFS_DAS_LEAF_SET_RMT,		"XFS_DAS_LEAF_SET_RMT" }, \
>  	{ XFS_DAS_LEAF_ALLOC_RMT,	"XFS_DAS_LEAF_ALLOC_RMT" }, \
>  	{ XFS_DAS_LEAF_REPLACE,		"XFS_DAS_LEAF_REPLACE" }, \
> @@ -525,8 +530,7 @@ struct xfs_attr_item {
>  	enum xfs_delattr_state		xattri_dela_state;
>  
>  	/*
> -	 * Indicates if the attr operation is a set or a remove
> -	 * XFS_ATTR_OP_FLAGS_{SET,REMOVE}
> +	 * Attr operation being performed - XFS_ATTR_OP_FLAGS_*
>  	 */
>  	unsigned int			xattri_op_flags;
>  
> @@ -568,4 +572,65 @@ void xfs_attri_destroy_cache(void);
>  int __init xfs_attrd_init_cache(void);
>  void xfs_attrd_destroy_cache(void);
>  
> +/*
> + * Check to see if the attr should be upgraded from non-existent or
> shortform to
> + * single-leaf-block attribute list.
> + */
> +static inline bool
> +xfs_attr_is_shortform(
> +	struct xfs_inode    *ip)
> +{
> +	return ip->i_afp->if_format == XFS_DINODE_FMT_LOCAL ||
> +	       (ip->i_afp->if_format == XFS_DINODE_FMT_EXTENTS &&
> +		ip->i_afp->if_nextents == 0);
> +}
> +
> +static inline enum xfs_delattr_state
> +xfs_attr_init_add_state(struct xfs_da_args *args)
> +{
> +	/*
> +	 * On a pure remove, we can remove the attr fork so when we are
> +	 * called to set the add state after the remove to set up the
> next
> +	 * replace state, we can hit this case here. However, we will
> not see
> +	 * an empty fork on logged replace operation, so if there is no
> attr
> +	 * fork then we are done here.
> +	 *
> +	 * XXX: The replace state changeover needs a bit of rework to
> +	 * avoid this quirk.
> +	 */
> +	if (!args->dp->i_afp)
> +		return XFS_DAS_DONE;
> +	if (xfs_attr_is_shortform(args->dp))
> +		return XFS_DAS_SF_ADD;
> +	if (xfs_attr_is_leaf(args->dp))
> +		return XFS_DAS_LEAF_ADD;
> +	return XFS_DAS_NODE_ADD;
> +}
> +
> +static inline enum xfs_delattr_state
> +xfs_attr_init_remove_state(struct xfs_da_args *args)
> +{
> +	if (xfs_attr_is_shortform(args->dp))
> +		return XFS_DAS_SF_REMOVE;
> +	if (xfs_attr_is_leaf(args->dp))
> +		return XFS_DAS_LEAF_REMOVE;
> +	return XFS_DAS_NODE_REMOVE;
> +}
> +
> +/*
> + * If we are logging the attributes, then we have to start with
> removal of the
> + * old attribute so that there is always consistent state that we
> can recover
> + * from if the system goes down part way through. We always log the
> new attr
> + * value, so even when we remove the attr first we still have the
> information in
> + * the log to finish the replace operation atomically.
> + */
> +static inline enum xfs_delattr_state
> +xfs_attr_init_replace_state(struct xfs_da_args *args)
> +{
> +	args->op_flags |= XFS_DA_OP_RENAME;
> +	if (xfs_has_larp(args->dp->i_mount))
> +		return xfs_attr_init_remove_state(args);
> +	return xfs_attr_init_add_state(args);
> +}
> +
>  #endif	/* __XFS_ATTR_H__ */
> diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c
> b/fs/xfs/libxfs/xfs_attr_leaf.c
> index e90bfd9d7551..ff5ed9319270 100644
> --- a/fs/xfs/libxfs/xfs_attr_leaf.c
> +++ b/fs/xfs/libxfs/xfs_attr_leaf.c
> @@ -446,6 +446,14 @@ xfs_attr3_leaf_read(
>   * Namespace helper routines
>  
> *====================================================================
> ====*/
>  
> +/*
> + * If we are in log recovery, then we want the lookup to ignore the
> INCOMPLETE
> + * flag on disk - if there's an incomplete attr then recovery needs
> to tear it
> + * down. If there's no incomplete attr, then recovery needs to tear
> that attr
> + * down to replace it with the attr that has been logged. In this
> case, the
> + * INCOMPLETE flag will not be set in attr->attr_filter, but rather
> + * XFS_DA_OP_RECOVERY will be set in args->op_flags.
> + */
>  static bool
>  xfs_attr_match(
>  	struct xfs_da_args	*args,
> @@ -453,14 +461,18 @@ xfs_attr_match(
>  	unsigned char		*name,
>  	int			flags)
>  {
> +
>  	if (args->namelen != namelen)
>  		return false;
>  	if (memcmp(args->name, name, namelen) != 0)
>  		return false;
> -	/*
> -	 * If we are looking for incomplete entries, show only those,
> else only
> -	 * show complete entries.
> -	 */
> +
> +	/* Recovery ignores the INCOMPLETE flag. */
> +	if ((args->op_flags & XFS_DA_OP_RECOVERY) &&
> +	    args->attr_filter == (flags & XFS_ATTR_NSP_ONDISK_MASK))
> +		return true;
> +
> +	/* All remaining matches need to be filtered by INCOMPLETE
> state. */
>  	if (args->attr_filter !=
>  	    (flags & (XFS_ATTR_NSP_ONDISK_MASK | XFS_ATTR_INCOMPLETE)))
>  		return false;
> @@ -819,7 +831,7 @@ xfs_attr_sf_removename(
>  	totsize -= size;
>  	if (totsize == sizeof(xfs_attr_sf_hdr_t) && xfs_has_attr2(mp)
> &&
>  	    (dp->i_df.if_format != XFS_DINODE_FMT_BTREE) &&
> -	    !(args->op_flags & XFS_DA_OP_ADDNAME)) {
> +	    !(args->op_flags & (XFS_DA_OP_ADDNAME | XFS_DA_OP_RENAME)))
> {
>  		xfs_attr_fork_remove(dp, args->trans);
>  	} else {
>  		xfs_idata_realloc(dp, -size, XFS_ATTR_FORK);
> diff --git a/fs/xfs/libxfs/xfs_da_btree.h
> b/fs/xfs/libxfs/xfs_da_btree.h
> index deb368d041e3..ca207d11bf66 100644
> --- a/fs/xfs/libxfs/xfs_da_btree.h
> +++ b/fs/xfs/libxfs/xfs_da_btree.h
> @@ -90,6 +90,7 @@ typedef struct xfs_da_args {
>  #define XFS_DA_OP_OKNOENT	(1u << 3) /* lookup op, ENOENT ok, else
> die */
>  #define XFS_DA_OP_CILOOKUP	(1u << 4) /* lookup returns CI name if
> found */
>  #define XFS_DA_OP_NOTIME	(1u << 5) /* don't update inode
> timestamps */
> +#define XFS_DA_OP_RECOVERY	(1u << 6) /* running a recovery
> operation */
>  
>  #define XFS_DA_OP_FLAGS \
>  	{ XFS_DA_OP_JUSTCHECK,	"JUSTCHECK" }, \
> diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
> index cac921ac18a8..991dee79c29c 100644
> --- a/fs/xfs/libxfs/xfs_defer.c
> +++ b/fs/xfs/libxfs/xfs_defer.c
> @@ -23,6 +23,8 @@
>  #include "xfs_bmap.h"
>  #include "xfs_alloc.h"
>  #include "xfs_buf.h"
> +#include "xfs_da_format.h"
> +#include "xfs_da_btree.h"
>  #include "xfs_attr.h"
>  
>  static struct kmem_cache	*xfs_defer_pending_cache;
> diff --git a/fs/xfs/libxfs/xfs_log_format.h
> b/fs/xfs/libxfs/xfs_log_format.h
> index a27492e99673..e430f294c747 100644
> --- a/fs/xfs/libxfs/xfs_log_format.h
> +++ b/fs/xfs/libxfs/xfs_log_format.h
> @@ -906,9 +906,10 @@ struct xfs_icreate_log {
>   * Flags for deferred attribute operations.
>   * Upper bits are flags, lower byte is type code
>   */
> -#define XFS_ATTR_OP_FLAGS_SET		1	/* Set the attribute
> */
> -#define XFS_ATTR_OP_FLAGS_REMOVE	2	/* Remove the attribute */
> -#define XFS_ATTR_OP_FLAGS_TYPE_MASK	0xFF	/* Flags type mask */
> +#define XFS_ATTR_OP_FLAGS_SET		(1u << 0) /* Set the
> attribute */
> +#define XFS_ATTR_OP_FLAGS_REMOVE	(1u << 1) /* Remove the
> attribute */
> +#define XFS_ATTR_OP_FLAGS_REPLACE	(1u << 2) /* Replace the
> attribute */
> +#define XFS_ATTR_OP_FLAGS_TYPE_MASK	0xFF	  /* Flags type mask
> */
>  
>  /*
>   * This is the structure used to lay out an attr log item in the
> diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
> index 5c52ee869272..df3059490af9 100644
> --- a/fs/xfs/xfs_acl.c
> +++ b/fs/xfs/xfs_acl.c
> @@ -10,12 +10,12 @@
>  #include "xfs_trans_resv.h"
>  #include "xfs_mount.h"
>  #include "xfs_inode.h"
> -#include "xfs_attr.h"
>  #include "xfs_trace.h"
>  #include "xfs_error.h"
>  #include "xfs_acl.h"
>  #include "xfs_da_format.h"
>  #include "xfs_da_btree.h"
> +#include "xfs_attr.h"
>  #include "xfs_trans.h"
>  
>  #include <linux/posix_acl_xattr.h>
> diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
> index 39af681897a2..a46379a9e9df 100644
> --- a/fs/xfs/xfs_attr_item.c
> +++ b/fs/xfs/xfs_attr_item.c
> @@ -490,9 +490,14 @@ xfs_attri_validate(
>  	if (attrp->__pad != 0)
>  		return false;
>  
> -	/* alfi_op_flags should be either a set or remove */
> -	if (op != XFS_ATTR_OP_FLAGS_SET && op !=
> XFS_ATTR_OP_FLAGS_REMOVE)
> +	switch (op) {
> +	case XFS_ATTR_OP_FLAGS_SET:
> +	case XFS_ATTR_OP_FLAGS_REMOVE:
> +	case XFS_ATTR_OP_FLAGS_REPLACE:
> +		break;
> +	default:
>  		return false;
> +	}
>  
>  	if (attrp->alfi_value_len > XATTR_SIZE_MAX)
>  		return false;
> @@ -553,11 +558,27 @@ xfs_attri_item_recover(
>  	args->namelen = attrp->alfi_name_len;
>  	args->hashval = xfs_da_hashname(args->name, args->namelen);
>  	args->attr_filter = attrp->alfi_attr_flags;
> +	args->op_flags = XFS_DA_OP_RECOVERY;
>  
> -	if (attrp->alfi_op_flags == XFS_ATTR_OP_FLAGS_SET) {
> +	switch (attr->xattri_op_flags) {
> +	case XFS_ATTR_OP_FLAGS_SET:
> +	case XFS_ATTR_OP_FLAGS_REPLACE:
>  		args->value = attrip->attri_value;
>  		args->valuelen = attrp->alfi_value_len;
>  		args->total = xfs_attr_calc_size(args, &local);
> +		if (xfs_inode_hasattr(args->dp))
I ran into a test failure and tracked it down to the above line.  I
suspect because xfs_inode_hasattr only checks to see if the inode has
an attr fork, it doesnt actually check to see if it has the attr we're
replacing.  So we fall into the replace code path where it should have
been the set code path.  If I replace it with the below line, the
failure is resolved:

	if (attr->xattri_op_flags == XFS_ATTR_OP_FLAGS_REPLACE)

I only encountered this bug after running with parent pointers though
which generates a lot more activity, but I figure it's not a bad idea
to catch things early.  There's one more test failure it's picking up,
though I havnt figured out the cause just yet.

The rest looks good though, I see the below lines address the issue of
the states needing to be initialized in the replay paths, so that
addresses the concerns in patches 4 and 13.  Thanks for all the larp
improvements!

Allison

> +			attr->xattri_dela_state =
> xfs_attr_init_replace_state(args);
> +		else
> +			attr->xattri_dela_state =
> xfs_attr_init_add_state(args);
> +		break;
> +	case XFS_ATTR_OP_FLAGS_REMOVE:
> +		if (!xfs_inode_hasattr(args->dp))
> +			goto out;
> +		attr->xattri_dela_state =
> xfs_attr_init_remove_state(args);
> +		break;
> +	default:
> +		error = -EFSCORRUPTED;
> +		goto out;
>  	}
>  
>  	xfs_init_attr_trans(args, &tres, &total);
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index e9eadc7337ce..64254895d083 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -15,7 +15,6 @@
>  #include "xfs_iwalk.h"
>  #include "xfs_itable.h"
>  #include "xfs_error.h"
> -#include "xfs_attr.h"
>  #include "xfs_bmap.h"
>  #include "xfs_bmap_util.h"
>  #include "xfs_fsops.h"
> @@ -37,6 +36,7 @@
>  #include "xfs_ioctl.h"
>  #include "xfs_da_format.h"
>  #include "xfs_da_btree.h"
> +#include "xfs_attr.h"
>  
>  #include <linux/mount.h>
>  #include <linux/namei.h>
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index c85bab6215e1..8783aeb096c4 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -4100,13 +4100,10 @@ DEFINE_ICLOG_EVENT(xlog_iclog_write);
>  
>  TRACE_DEFINE_ENUM(XFS_DAS_UNINIT);
>  TRACE_DEFINE_ENUM(XFS_DAS_SF_ADD);
> -TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ADD);
> -TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
> -TRACE_DEFINE_ENUM(XFS_DAS_RMTBLK);
> -TRACE_DEFINE_ENUM(XFS_DAS_RM_NAME);
> -TRACE_DEFINE_ENUM(XFS_DAS_RM_SHRINK);
>  TRACE_DEFINE_ENUM(XFS_DAS_SF_REMOVE);
> +TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ADD);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_REMOVE);
> +TRACE_DEFINE_ENUM(XFS_DAS_NODE_ADD);
>  TRACE_DEFINE_ENUM(XFS_DAS_NODE_REMOVE);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_SET_RMT);
>  TRACE_DEFINE_ENUM(XFS_DAS_LEAF_ALLOC_RMT);
> @@ -4142,6 +4139,9 @@ DECLARE_EVENT_CLASS(xfs_das_state_class,
>  DEFINE_EVENT(xfs_das_state_class, name, \
>  	TP_PROTO(int das, struct xfs_inode *ip), \
>  	TP_ARGS(das, ip))
> +DEFINE_DAS_STATE_EVENT(xfs_attr_defer_add);
> +DEFINE_DAS_STATE_EVENT(xfs_attr_defer_replace);
> +DEFINE_DAS_STATE_EVENT(xfs_attr_defer_remove);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_sf_addname_return);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_set_iter_return);
>  DEFINE_DAS_STATE_EVENT(xfs_attr_leaf_addname_return);
> diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
> index 0d050f8829ef..6935edcaa112 100644
> --- a/fs/xfs/xfs_xattr.c
> +++ b/fs/xfs/xfs_xattr.c
> @@ -12,9 +12,9 @@
>  #include "xfs_trans_resv.h"
>  #include "xfs_mount.h"
>  #include "xfs_inode.h"
> -#include "xfs_attr.h"
>  #include "xfs_acl.h"
>  #include "xfs_da_btree.h"
> +#include "xfs_attr.h"
>  
>  #include <linux/posix_acl_xattr.h>
>  

Re: [PATCH 16/16] xfs: ATTR_REPLACE algorithm with LARP enabled needs rework

[Dave Chinner]

On Thu, Apr 28, 2022 at 12:02:17AM -0700, Alli wrote:
> On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > We can't use the same algorithm for replacing an existing attribute
> > when logging attributes. The existing algorithm is essentially:
> > 
> > 1. create new attr w/ INCOMPLETE
> > 2. atomically flip INCOMPLETE flags between old + new attribute
> > 3. remove old attr which is marked w/ INCOMPLETE
> > 
> > This algorithm guarantees that we see either the old or new
> > attribute, and if we fail after the atomic flag flip, we don't have
> > to recover the removal of the old attr because we never see
> > INCOMPLETE attributes in lookups.
....
> > diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
> > index 39af681897a2..a46379a9e9df 100644
> > --- a/fs/xfs/xfs_attr_item.c
> > +++ b/fs/xfs/xfs_attr_item.c
> > @@ -490,9 +490,14 @@ xfs_attri_validate(
> >  	if (attrp->__pad != 0)
> >  		return false;
> >  
> > -	/* alfi_op_flags should be either a set or remove */
> > -	if (op != XFS_ATTR_OP_FLAGS_SET && op !=
> > XFS_ATTR_OP_FLAGS_REMOVE)
> > +	switch (op) {
> > +	case XFS_ATTR_OP_FLAGS_SET:
> > +	case XFS_ATTR_OP_FLAGS_REMOVE:
> > +	case XFS_ATTR_OP_FLAGS_REPLACE:
> > +		break;
> > +	default:
> >  		return false;
> > +	}
> >  
> >  	if (attrp->alfi_value_len > XATTR_SIZE_MAX)
> >  		return false;
> > @@ -553,11 +558,27 @@ xfs_attri_item_recover(
> >  	args->namelen = attrp->alfi_name_len;
> >  	args->hashval = xfs_da_hashname(args->name, args->namelen);
> >  	args->attr_filter = attrp->alfi_attr_flags;
> > +	args->op_flags = XFS_DA_OP_RECOVERY;
> >  
> > -	if (attrp->alfi_op_flags == XFS_ATTR_OP_FLAGS_SET) {
> > +	switch (attr->xattri_op_flags) {
> > +	case XFS_ATTR_OP_FLAGS_SET:
> > +	case XFS_ATTR_OP_FLAGS_REPLACE:
> >  		args->value = attrip->attri_value;
> >  		args->valuelen = attrp->alfi_value_len;
> >  		args->total = xfs_attr_calc_size(args, &local);
> > +		if (xfs_inode_hasattr(args->dp))
> I ran into a test failure and tracked it down to the above line.  I
> suspect because xfs_inode_hasattr only checks to see if the inode has
> an attr fork, it doesnt actually check to see if it has the attr we're
> replacing.

Right, that was intentional. It is based on the fact that if we
are recovering a set or a replace operation, we have to remove the
INCOMPLETE xattr first. However, if the attr fork is empty, there's
no INCOMPLETE xattr to remove, and so we can just go straight to the
set operation to create the new value.

Hmmm - what was the failure? Was it a null pointer dereference
on ip->i_afp? I wonder if you hit the corner case where attr removal
can remove the attr fork, and that's when it crashed and we've tried
to recover from?

Oh, I think I might have missed a case there. If you look at
xfs_attr_sf_removename() I added a case to avoid removing the attr
fork when XFS_DA_OP_RENAME is set because we don't want to remove it
when we are about to add to it again. But I didn't add the same
logic to xfs_attr3_leaf_to_shortform() which can also trash the attr
fork if the last attr we remove from the attr fork is larger than
would fit in a sf attr fork. Hence we go straight from leaf form to
no attr fork at all.

Ok, that's definitely a bug, I'll need to fix that, and it could be
the cause of this issue as removing the attr fork will set
forkoff to 0 and so the inode will not have an attr fork
instantiated when it is read into memory...


> So we fall into the replace code path where it should have
> been the set code path.  If I replace it with the below line, the
> failure is resolved:
> 
> 	if (attr->xattri_op_flags == XFS_ATTR_OP_FLAGS_REPLACE)
> 
> I only encountered this bug after running with parent pointers though
> which generates a lot more activity, but I figure it's not a bad idea
> to catch things early.  There's one more test failure it's picking up,
> though I havnt figured out the cause just yet.

Yup, that's a good idea.

> The rest looks good though, I see the below lines address the issue of
> the states needing to be initialized in the replay paths, so that
> addresses the concerns in patches 4 and 13.  Thanks for all the larp
> improvements!

I'm going to try to move them up into patches 4 and 13, so that
recovery at least tries to function correctly as we move through the
patch set.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

Re: [PATCH 16/16] xfs: ATTR_REPLACE algorithm with LARP enabled needs rework

[Alli]

On Tue, 2022-05-03 at 17:40 +1000, Dave Chinner wrote:
> On Thu, Apr 28, 2022 at 12:02:17AM -0700, Alli wrote:
> > On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> > > From: Dave Chinner <dchinner@redhat.com>
> > > 
> > > We can't use the same algorithm for replacing an existing
> > > attribute
> > > when logging attributes. The existing algorithm is essentially:
> > > 
> > > 1. create new attr w/ INCOMPLETE
> > > 2. atomically flip INCOMPLETE flags between old + new attribute
> > > 3. remove old attr which is marked w/ INCOMPLETE
> > > 
> > > This algorithm guarantees that we see either the old or new
> > > attribute, and if we fail after the atomic flag flip, we don't
> > > have
> > > to recover the removal of the old attr because we never see
> > > INCOMPLETE attributes in lookups.
> ....
> > > diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
> > > index 39af681897a2..a46379a9e9df 100644
> > > --- a/fs/xfs/xfs_attr_item.c
> > > +++ b/fs/xfs/xfs_attr_item.c
> > > @@ -490,9 +490,14 @@ xfs_attri_validate(
> > >  	if (attrp->__pad != 0)
> > >  		return false;
> > >  
> > > -	/* alfi_op_flags should be either a set or remove */
> > > -	if (op != XFS_ATTR_OP_FLAGS_SET && op !=
> > > XFS_ATTR_OP_FLAGS_REMOVE)
> > > +	switch (op) {
> > > +	case XFS_ATTR_OP_FLAGS_SET:
> > > +	case XFS_ATTR_OP_FLAGS_REMOVE:
> > > +	case XFS_ATTR_OP_FLAGS_REPLACE:
> > > +		break;
> > > +	default:
> > >  		return false;
> > > +	}
> > >  
> > >  	if (attrp->alfi_value_len > XATTR_SIZE_MAX)
> > >  		return false;
> > > @@ -553,11 +558,27 @@ xfs_attri_item_recover(
> > >  	args->namelen = attrp->alfi_name_len;
> > >  	args->hashval = xfs_da_hashname(args->name, args->namelen);
> > >  	args->attr_filter = attrp->alfi_attr_flags;
> > > +	args->op_flags = XFS_DA_OP_RECOVERY;
> > >  
> > > -	if (attrp->alfi_op_flags == XFS_ATTR_OP_FLAGS_SET) {
> > > +	switch (attr->xattri_op_flags) {
> > > +	case XFS_ATTR_OP_FLAGS_SET:
> > > +	case XFS_ATTR_OP_FLAGS_REPLACE:
> > >  		args->value = attrip->attri_value;
> > >  		args->valuelen = attrp->alfi_value_len;
> > >  		args->total = xfs_attr_calc_size(args, &local);
> > > +		if (xfs_inode_hasattr(args->dp))
> > I ran into a test failure and tracked it down to the above line.  I
> > suspect because xfs_inode_hasattr only checks to see if the inode
> > has
> > an attr fork, it doesnt actually check to see if it has the attr
> > we're
> > replacing.
> 
> Right, that was intentional. It is based on the fact that if we
> are recovering a set or a replace operation, we have to remove the
> INCOMPLETE xattr first. However, if the attr fork is empty, there's
> no INCOMPLETE xattr to remove, and so we can just go straight to the
> set operation to create the new value.
> 
> Hmmm - what was the failure? Was it a null pointer dereference
> on ip->i_afp? I wonder if you hit the corner case where attr removal
> can remove the attr fork, and that's when it crashed and we've tried
> to recover from?
No, the actual shutdown was from the error inject that the test case
uses.  The unexpected part was a set operation returning -ENODATA
because we incorrectly fell down the rename path.  I suspect the reason
the parent pointers exposed it was because the presence of the parent
pointer caused the attr fork to not be empty and so xfs_inode_hasattr
succeeds. 

> 
> Oh, I think I might have missed a case there. If you look at
> xfs_attr_sf_removename() I added a case to avoid removing the attr
> fork when XFS_DA_OP_RENAME is set because we don't want to remove it
> when we are about to add to it again. But I didn't add the same
> logic to xfs_attr3_leaf_to_shortform() which can also trash the attr
> fork if the last attr we remove from the attr fork is larger than
> would fit in a sf attr fork. Hence we go straight from leaf form to
> no attr fork at all.
> 
> Ok, that's definitely a bug, I'll need to fix that, and it could be
> the cause of this issue as removing the attr fork will set
> forkoff to 0 and so the inode will not have an attr fork
> instantiated when it is read into memory...
> 
> 
Ah, that could be it then.  The last failing test case is: expanding
the fork into node form, setting the inject, and attempting a rename.
 The correct result should be that it finds the attr correctly renamed,
but instead finds no attr.  So that sounds like what you've described.
 I will wait for your fix and then retest.  Thx for all your help here!

Allison

> > So we fall into the replace code path where it should have
> > been the set code path.  If I replace it with the below line, the
> > failure is resolved:
> > 
> > 	if (attr->xattri_op_flags == XFS_ATTR_OP_FLAGS_REPLACE)
> > 
> > I only encountered this bug after running with parent pointers
> > though
> > which generates a lot more activity, but I figure it's not a bad
> > idea
> > to catch things early.  There's one more test failure it's picking
> > up,
> > though I havnt figured out the cause just yet.
> 
> Yup, that's a good idea.
> 
> > The rest looks good though, I see the below lines address the issue
> > of
> > the states needing to be initialized in the replay paths, so that
> > addresses the concerns in patches 4 and 13.  Thanks for all the
> > larp
> > improvements!
> 
> I'm going to try to move them up into patches 4 and 13, so that
> recovery at least tries to function correctly as we move through the
> patch set.
> 
> Cheers,
> 
> Dave.

Re: [PATCH 16/16] xfs: ATTR_REPLACE algorithm with LARP enabled needs rework

[Dave Chinner]

On Tue, May 03, 2022 at 06:30:23PM -0700, Alli wrote:
> On Tue, 2022-05-03 at 17:40 +1000, Dave Chinner wrote:
> > On Thu, Apr 28, 2022 at 12:02:17AM -0700, Alli wrote:
> > > On Thu, 2022-04-14 at 19:44 +1000, Dave Chinner wrote:
> > > > From: Dave Chinner <dchinner@redhat.com>
> > > > 
> > > > We can't use the same algorithm for replacing an existing
> > > > attribute
> > > > when logging attributes. The existing algorithm is essentially:
> > > > 
> > > > 1. create new attr w/ INCOMPLETE
> > > > 2. atomically flip INCOMPLETE flags between old + new attribute
> > > > 3. remove old attr which is marked w/ INCOMPLETE
> > > > 
> > > > This algorithm guarantees that we see either the old or new
> > > > attribute, and if we fail after the atomic flag flip, we don't
> > > > have
> > > > to recover the removal of the old attr because we never see
> > > > INCOMPLETE attributes in lookups.
> > ....
> > > > diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
> > > > index 39af681897a2..a46379a9e9df 100644
> > > > --- a/fs/xfs/xfs_attr_item.c
> > > > +++ b/fs/xfs/xfs_attr_item.c
> > > > @@ -490,9 +490,14 @@ xfs_attri_validate(
> > > >  	if (attrp->__pad != 0)
> > > >  		return false;
> > > >  
> > > > -	/* alfi_op_flags should be either a set or remove */
> > > > -	if (op != XFS_ATTR_OP_FLAGS_SET && op !=
> > > > XFS_ATTR_OP_FLAGS_REMOVE)
> > > > +	switch (op) {
> > > > +	case XFS_ATTR_OP_FLAGS_SET:
> > > > +	case XFS_ATTR_OP_FLAGS_REMOVE:
> > > > +	case XFS_ATTR_OP_FLAGS_REPLACE:
> > > > +		break;
> > > > +	default:
> > > >  		return false;
> > > > +	}
> > > >  
> > > >  	if (attrp->alfi_value_len > XATTR_SIZE_MAX)
> > > >  		return false;
> > > > @@ -553,11 +558,27 @@ xfs_attri_item_recover(
> > > >  	args->namelen = attrp->alfi_name_len;
> > > >  	args->hashval = xfs_da_hashname(args->name, args->namelen);
> > > >  	args->attr_filter = attrp->alfi_attr_flags;
> > > > +	args->op_flags = XFS_DA_OP_RECOVERY;
> > > >  
> > > > -	if (attrp->alfi_op_flags == XFS_ATTR_OP_FLAGS_SET) {
> > > > +	switch (attr->xattri_op_flags) {
> > > > +	case XFS_ATTR_OP_FLAGS_SET:
> > > > +	case XFS_ATTR_OP_FLAGS_REPLACE:
> > > >  		args->value = attrip->attri_value;
> > > >  		args->valuelen = attrp->alfi_value_len;
> > > >  		args->total = xfs_attr_calc_size(args, &local);
> > > > +		if (xfs_inode_hasattr(args->dp))
> > > I ran into a test failure and tracked it down to the above line.  I
> > > suspect because xfs_inode_hasattr only checks to see if the inode
> > > has
> > > an attr fork, it doesnt actually check to see if it has the attr
> > > we're
> > > replacing.
> > 
> > Right, that was intentional. It is based on the fact that if we
> > are recovering a set or a replace operation, we have to remove the
> > INCOMPLETE xattr first. However, if the attr fork is empty, there's
> > no INCOMPLETE xattr to remove, and so we can just go straight to the
> > set operation to create the new value.
> > 
> > Hmmm - what was the failure? Was it a null pointer dereference
> > on ip->i_afp? I wonder if you hit the corner case where attr removal
> > can remove the attr fork, and that's when it crashed and we've tried
> > to recover from?
> No, the actual shutdown was from the error inject that the test case
> uses.  The unexpected part was a set operation returning -ENODATA
> because we incorrectly fell down the rename path. 

That's not correct - recovery of a set operation has to remove
the INCOMPLETE attr that is was in the process of being built. If
we are in recovery and we don't find an existing entry, we should
just then fall through the state machine to the set operation
as there was nothing to remove.

-ENOATTR/-ENODATA in that case is valid, it just sounds like we
didn't find an incomplete attr to remove and didn't handle the case
correctly.

> I suspect the reason
> the parent pointers exposed it was because the presence of the parent
> pointer caused the attr fork to not be empty and so xfs_inode_hasattr
> succeeds. 

I think it's the case where we fail immediately after logging the
first SET intent to the journal, and haven't actually logged
any other changes yet. That first intent can only be logged after
the attr fork has been created and logged, so -ENODATA is a case
recovery is supposed to handle for a SET operation.

> > Oh, I think I might have missed a case there. If you look at
> > xfs_attr_sf_removename() I added a case to avoid removing the attr
> > fork when XFS_DA_OP_RENAME is set because we don't want to remove it
> > when we are about to add to it again. But I didn't add the same
> > logic to xfs_attr3_leaf_to_shortform() which can also trash the attr
> > fork if the last attr we remove from the attr fork is larger than
> > would fit in a sf attr fork. Hence we go straight from leaf form to
> > no attr fork at all.
> > 
> > Ok, that's definitely a bug, I'll need to fix that, and it could be
> > the cause of this issue as removing the attr fork will set
> > forkoff to 0 and so the inode will not have an attr fork
> > instantiated when it is read into memory...
> > 
> > 
> Ah, that could be it then.  The last failing test case is: expanding
> the fork into node form, setting the inject, and attempting a rename.

Ah, so that's likely how we get the situation I suggested above - we
commit the node form expansion without other modifications but
include the SET intent, so if we recover that node form
transformation, we most definitely have a SET intent without an
INCOMPLETE attr to remove...

I'll add it to the list.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com