[PATCH v20 00/14] Delay Ready Attributes

[PATCH v20 00/14] Delay Ready Attributes

[Allison Henderson]

Hi all,

This set is a subset of a larger series for Dealyed Attributes. Which is a
subset of a yet larger series for parent pointers. Delayed attributes allow
attribute operations (set and remove) to be logged and committed in the same
way that other delayed operations do. This allows more complex operations (like
parent pointers) to be broken up into multiple smaller transactions. To do
this, the existing attr operations must be modified to operate as a delayed
operation.  This means that they cannot roll, commit, or finish transactions.
Instead, they return -EAGAIN to allow the calling function to handle the
transaction.  In this series, we focus on only the delayed attribute portion.
We will introduce parent pointers in a later set.

The set as a whole is a bit much to digest at once, so I usually send out the
smaller sub series to reduce reviewer burn out.  But the entire extended series
is visible through the included github links.

Updates since v19: Added Darricks fix for the remote block accounting as well as
some minor nits about the default assert in xfs_attr_set_iter.  Spent quite     
a bit of time testing this cycle to weed out any more unexpected bugs.

xfs: Fix default ASSERT in xfs_attr_set_iter
  Replaced the assert with ASSERT(0);

xfs: Add delay ready attr remove routines
  Added Darricks fix for remote block accounting

This series can be viewed on github here:
https://github.com/allisonhenderson/xfs_work/tree/delay_ready_attrs_v20

As well as the extended delayed attribute and parent pointer series:
https://github.com/allisonhenderson/xfs_work/tree/delay_ready_attrs_v20_extended

And the test cases:
https://github.com/allisonhenderson/xfs_work/tree/pptr_xfstestsv3
In order to run the test cases, you will need have the corresponding xfsprogs

changes as well.  Which can be found here:
https://github.com/allisonhenderson/xfs_work/tree/delay_ready_attrs_xfsprogs_v20
https://github.com/allisonhenderson/xfs_work/tree/delay_ready_attrs_xfsprogs_v20_extended

To run the xfs attributes tests run:
check -g attr

To run as delayed attributes run:
export MOUNT_OPTIONS="-o delattr"
check -g attr

To run parent pointer tests:
check -g parent

I've also made the corresponding updates to the user space side as well, and ported anything
they need to seat correctly.

Questions, comment and feedback appreciated! 

Thanks all!
Allison

Allison Henderson (14):
  xfs: Reverse apply 72b97ea40d
  xfs: Add xfs_attr_node_remove_name
  xfs: Refactor xfs_attr_set_shortform
  xfs: Separate xfs_attr_node_addname and
    xfs_attr_node_addname_clear_incomplete
  xfs: Add helper xfs_attr_node_addname_find_attr
  xfs: Hoist xfs_attr_node_addname
  xfs: Hoist xfs_attr_leaf_addname
  xfs: Hoist node transaction handling
  xfs: Add delay ready attr remove routines
  xfs: Add delay ready attr set routines
  xfs: Remove xfs_attr_rmtval_set
  xfs: Clean up xfs_attr_node_addname_clear_incomplete
  xfs: Fix default ASSERT in xfs_attr_set_iter
  xfs: Make attr name schemes consistent

 fs/xfs/libxfs/xfs_attr.c        | 910 ++++++++++++++++++++++++----------------
 fs/xfs/libxfs/xfs_attr.h        | 403 ++++++++++++++++++
 fs/xfs/libxfs/xfs_attr_leaf.c   |   4 +-
 fs/xfs/libxfs/xfs_attr_leaf.h   |   2 +-
 fs/xfs/libxfs/xfs_attr_remote.c | 167 ++++----
 fs/xfs/libxfs/xfs_attr_remote.h |   8 +-
 fs/xfs/xfs_attr_inactive.c      |   2 +-
 fs/xfs/xfs_trace.h              |   2 -
 8 files changed, 1032 insertions(+), 466 deletions(-)

-- 
2.7.4

[PATCH v20 01/14] xfs: Reverse apply 72b97ea40d

[Allison Henderson]

Originally we added this patch to help modularize the attr code in
preparation for delayed attributes and the state machine it requires.
However, later reviews found that this slightly alters the transaction
handling as the helper function is ambiguous as to whether the
transaction is diry or clean.  This may cause a dirty transaction to be
included in the next roll, where previously it had not.  To preserve the
existing code flow, we reverse apply this commit.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/libxfs/xfs_attr.c | 28 +++++++++-------------------
 1 file changed, 9 insertions(+), 19 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 96146f4..190b46d 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -1214,24 +1214,6 @@ int xfs_attr_node_removename_setup(
 	return 0;
 }
 
-STATIC int
-xfs_attr_node_remove_rmt(
-	struct xfs_da_args	*args,
-	struct xfs_da_state	*state)
-{
-	int			error = 0;
-
-	error = xfs_attr_rmtval_remove(args);
-	if (error)
-		return error;
-
-	/*
-	 * Refill the state structure with buffers, the prior calls released our
-	 * buffers.
-	 */
-	return xfs_attr_refillstate(state);
-}
-
 /*
  * Remove a name from a B-tree attribute list.
  *
@@ -1260,7 +1242,15 @@ xfs_attr_node_removename(
 	 * overflow the maximum size of a transaction and/or hit a deadlock.
 	 */
 	if (args->rmtblkno > 0) {
-		error = xfs_attr_node_remove_rmt(args, state);
+		error = xfs_attr_rmtval_remove(args);
+		if (error)
+			goto out;
+
+		/*
+		 * Refill the state structure with buffers, the prior calls
+		 * released our buffers.
+		 */
+		error = xfs_attr_refillstate(state);
 		if (error)
 			goto out;
 	}
-- 
2.7.4

[PATCH v20 02/14] xfs: Add xfs_attr_node_remove_name

[Allison Henderson]

This patch pulls a new helper function xfs_attr_node_remove_name out
of xfs_attr_node_remove_step.  This helps to modularize
xfs_attr_node_remove_step which will help make the delayed attribute
code easier to follow

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 190b46d..8a08d5b 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -1214,6 +1214,25 @@ int xfs_attr_node_removename_setup(
 	return 0;
 }
 
+STATIC int
+xfs_attr_node_remove_name(
+	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 a name from a B-tree attribute list.
  *
@@ -1226,7 +1245,6 @@ xfs_attr_node_removename(
 	struct xfs_da_args	*args)
 {
 	struct xfs_da_state	*state;
-	struct xfs_da_state_blk	*blk;
 	int			retval, error;
 	struct xfs_inode	*dp = args->dp;
 
@@ -1254,14 +1272,7 @@ xfs_attr_node_removename(
 		if (error)
 			goto out;
 	}
-
-	/*
-	 * 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);
+	retval = xfs_attr_node_remove_name(args, state);
 
 	/*
 	 * Check to see if the tree needs to be collapsed.
-- 
2.7.4

[PATCH v20 03/14] xfs: Refactor xfs_attr_set_shortform

[Allison Henderson]

This patch is actually the combination of patches from the previous
version (v18).  Initially patch 3 hoisted xfs_attr_set_shortform, and
the next added the helper xfs_attr_set_fmt. xfs_attr_set_fmt is similar
the old xfs_attr_set_shortform. It returns 0 when the attr has been set
and no further action is needed. It returns -EAGAIN when shortform has
been transformed to leaf, and the calling function should proceed the
set the attr in leaf form.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 fs/xfs/libxfs/xfs_attr.c | 42 ++++++++++++++----------------------------
 1 file changed, 14 insertions(+), 28 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 8a08d5b..0ec1547 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -236,16 +236,11 @@ xfs_attr_is_shortform(
 		ip->i_afp->if_nextents == 0);
 }
 
-/*
- * Attempts to set an attr in shortform, or converts short form to leaf form if
- * there is not enough room.  If the attr is set, the transaction is committed
- * and set to NULL.
- */
 STATIC int
-xfs_attr_set_shortform(
-	struct xfs_da_args	*args,
-	struct xfs_buf		**leaf_bp)
+xfs_attr_set_fmt(
+	struct xfs_da_args	*args)
 {
+	struct xfs_buf          *leaf_bp = NULL;
 	struct xfs_inode	*dp = args->dp;
 	int			error, error2 = 0;
 
@@ -258,29 +253,29 @@ xfs_attr_set_shortform(
 		args->trans = NULL;
 		return error ? error : error2;
 	}
+
 	/*
 	 * It won't fit in the shortform, transform to a leaf block.  GROT:
 	 * another possible req'mt for a double-split btree op.
 	 */
-	error = xfs_attr_shortform_to_leaf(args, leaf_bp);
+	error = xfs_attr_shortform_to_leaf(args, &leaf_bp);
 	if (error)
 		return error;
 
 	/*
 	 * Prevent the leaf buffer from being unlocked so that a concurrent AIL
 	 * push cannot grab the half-baked leaf buffer and run into problems
-	 * with the write verifier. Once we're done rolling the transaction we
-	 * can release the hold and add the attr to the leaf.
+	 * with the write verifier.
 	 */
-	xfs_trans_bhold(args->trans, *leaf_bp);
+	xfs_trans_bhold(args->trans, leaf_bp);
 	error = xfs_defer_finish(&args->trans);
-	xfs_trans_bhold_release(args->trans, *leaf_bp);
+	xfs_trans_bhold_release(args->trans, leaf_bp);
 	if (error) {
-		xfs_trans_brelse(args->trans, *leaf_bp);
+		xfs_trans_brelse(args->trans, leaf_bp);
 		return error;
 	}
 
-	return 0;
+	return -EAGAIN;
 }
 
 /*
@@ -291,8 +286,7 @@ xfs_attr_set_args(
 	struct xfs_da_args	*args)
 {
 	struct xfs_inode	*dp = args->dp;
-	struct xfs_buf          *leaf_bp = NULL;
-	int			error = 0;
+	int			error;
 
 	/*
 	 * If the attribute list is already in leaf format, jump straight to
@@ -301,15 +295,8 @@ xfs_attr_set_args(
 	 * again.
 	 */
 	if (xfs_attr_is_shortform(dp)) {
-
-		/*
-		 * If the attr was successfully set in shortform, the
-		 * transaction is committed and set to NULL.  Otherwise, is it
-		 * converted from shortform to leaf, and the transaction is
-		 * retained.
-		 */
-		error = xfs_attr_set_shortform(args, &leaf_bp);
-		if (error || !args->trans)
+		error = xfs_attr_set_fmt(args);
+		if (error != -EAGAIN)
 			return error;
 	}
 
@@ -344,8 +331,7 @@ xfs_attr_set_args(
 			return error;
 	}
 
-	error = xfs_attr_node_addname(args);
-	return error;
+	return xfs_attr_node_addname(args);
 }
 
 /*
-- 
2.7.4

[PATCH v20 04/14] xfs: Separate xfs_attr_node_addname and xfs_attr_node_addname_clear_incomplete

[Allison Henderson]

This patch separate xfs_attr_node_addname into two functions.  This will
help to make it easier to hoist parts of xfs_attr_node_addname that need
state management

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/libxfs/xfs_attr.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 0ec1547..ad44d77 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -54,6 +54,7 @@ STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);
 STATIC int xfs_attr_node_get(xfs_da_args_t *args);
 STATIC int xfs_attr_node_addname(xfs_da_args_t *args);
 STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
+STATIC int xfs_attr_node_addname_clear_incomplete(struct xfs_da_args *args);
 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);
@@ -1073,6 +1074,28 @@ xfs_attr_node_addname(
 			return error;
 	}
 
+	error = xfs_attr_node_addname_clear_incomplete(args);
+	if (error)
+		goto out;
+	retval = 0;
+out:
+	if (state)
+		xfs_da_state_free(state);
+	if (error)
+		return error;
+	return retval;
+}
+
+
+STATIC int
+xfs_attr_node_addname_clear_incomplete(
+	struct xfs_da_args		*args)
+{
+	struct xfs_da_state		*state = NULL;
+	struct xfs_da_state_blk		*blk;
+	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.
-- 
2.7.4

[PATCH v20 05/14] xfs: Add helper xfs_attr_node_addname_find_attr

[Allison Henderson]

This patch separates the first half of xfs_attr_node_addname into a
helper function xfs_attr_node_addname_find_attr.  It also replaces the
restart goto with an EAGAIN return code driven by a loop in the calling
function.  This looks odd now, but will clean up nicly once we introduce
the state machine.  It will also enable hoisting the last state out of
xfs_attr_node_addname with out having to plumb in a "done" parameter to
know if we need to move to the next state or not.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 fs/xfs/libxfs/xfs_attr.c | 87 ++++++++++++++++++++++++++++++------------------
 1 file changed, 54 insertions(+), 33 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index ad44d77..5f56b05 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -52,7 +52,10 @@ STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);
  * Internal routines when attribute list is more than one block.
  */
 STATIC int xfs_attr_node_get(xfs_da_args_t *args);
-STATIC int xfs_attr_node_addname(xfs_da_args_t *args);
+STATIC int xfs_attr_node_addname(struct xfs_da_args *args,
+				 struct xfs_da_state *state);
+STATIC int xfs_attr_node_addname_find_attr(struct xfs_da_args *args,
+				 struct xfs_da_state **state);
 STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
 STATIC int xfs_attr_node_addname_clear_incomplete(struct xfs_da_args *args);
 STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
@@ -287,6 +290,7 @@ xfs_attr_set_args(
 	struct xfs_da_args	*args)
 {
 	struct xfs_inode	*dp = args->dp;
+	struct xfs_da_state     *state;
 	int			error;
 
 	/*
@@ -332,7 +336,14 @@ xfs_attr_set_args(
 			return error;
 	}
 
-	return xfs_attr_node_addname(args);
+	do {
+		error = xfs_attr_node_addname_find_attr(args, &state);
+		if (error)
+			return error;
+		error = xfs_attr_node_addname(args, state);
+	} while (error == -EAGAIN);
+
+	return error;
 }
 
 /*
@@ -896,48 +907,26 @@ xfs_attr_node_hasname(
  * External routines when attribute list size > geo->blksize
  *========================================================================*/
 
-/*
- * Add a name to a Btree-format attribute list.
- *
- * 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.
- */
 STATIC int
-xfs_attr_node_addname(
-	struct xfs_da_args	*args)
+xfs_attr_node_addname_find_attr(
+	struct xfs_da_args	*args,
+	struct xfs_da_state     **state)
 {
-	struct xfs_da_state	*state;
-	struct xfs_da_state_blk	*blk;
-	struct xfs_inode	*dp;
-	int			retval, error;
-
-	trace_xfs_attr_node_addname(args);
+	int			retval;
 
 	/*
-	 * Fill in bucket of arguments/results/context to carry around.
-	 */
-	dp = args->dp;
-restart:
-	/*
 	 * Search to see if name already exists, and get back a pointer
 	 * to where it should go.
 	 */
-	error = 0;
-	retval = xfs_attr_node_hasname(args, &state);
+	retval = xfs_attr_node_hasname(args, state);
 	if (retval != -ENOATTR && retval != -EEXIST)
-		goto out;
+		goto error;
 
-	blk = &state->path.blk[ state->path.active-1 ];
-	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
 	if (retval == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
-		goto out;
+		goto error;
 	if (retval == -EEXIST) {
 		if (args->attr_flags & XATTR_CREATE)
-			goto out;
+			goto error;
 
 		trace_xfs_attr_node_replace(args);
 
@@ -955,6 +944,38 @@ xfs_attr_node_addname(
 		args->rmtvaluelen = 0;
 	}
 
+	return 0;
+error:
+	if (*state)
+		xfs_da_state_free(*state);
+	return retval;
+}
+
+/*
+ * Add a name to a Btree-format attribute list.
+ *
+ * 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.
+ */
+STATIC int
+xfs_attr_node_addname(
+	struct xfs_da_args	*args,
+	struct xfs_da_state	*state)
+{
+	struct xfs_da_state_blk	*blk;
+	struct xfs_inode	*dp;
+	int			retval, error;
+
+	trace_xfs_attr_node_addname(args);
+
+	dp = args->dp;
+	blk = &state->path.blk[state->path.active-1];
+	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
+
 	retval = xfs_attr3_leaf_add(blk->bp, state->args);
 	if (retval == -ENOSPC) {
 		if (state->path.active == 1) {
@@ -980,7 +1001,7 @@ xfs_attr_node_addname(
 			if (error)
 				goto out;
 
-			goto restart;
+			return -EAGAIN;
 		}
 
 		/*
-- 
2.7.4

[PATCH v20 06/14] xfs: Hoist xfs_attr_node_addname

[Allison Henderson]

This patch hoists the later half of xfs_attr_node_addname into
the calling function.  We do this because it is this area that
will need the most state management, and we want to keep such
code in the same scope as much as possible

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 fs/xfs/libxfs/xfs_attr.c | 159 ++++++++++++++++++++++-------------------------
 1 file changed, 75 insertions(+), 84 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 5f56b05..b35c742 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -52,6 +52,7 @@ STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);
  * Internal routines when attribute list is more than one block.
  */
 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_da_args *args,
 				 struct xfs_da_state *state);
 STATIC int xfs_attr_node_addname_find_attr(struct xfs_da_args *args,
@@ -290,8 +291,8 @@ xfs_attr_set_args(
 	struct xfs_da_args	*args)
 {
 	struct xfs_inode	*dp = args->dp;
-	struct xfs_da_state     *state;
-	int			error;
+	struct xfs_da_state     *state = NULL;
+	int			error = 0;
 
 	/*
 	 * If the attribute list is already in leaf format, jump straight to
@@ -342,7 +343,75 @@ xfs_attr_set_args(
 			return error;
 		error = xfs_attr_node_addname(args, state);
 	} while (error == -EAGAIN);
+	if (error)
+		return error;
 
+	/*
+	 * Commit the leaf addition or btree split and start the next
+	 * trans in the chain.
+	 */
+	error = xfs_trans_roll_inode(&args->trans, dp);
+	if (error)
+		goto out;
+
+	/*
+	 * 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) {
+		error = xfs_attr_rmtval_set(args);
+		if (error)
+			return error;
+	}
+
+	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
+		/*
+		 * Added a "remote" value, just clear the incomplete flag.
+		 */
+		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.
+	 */
+	error = xfs_attr3_leaf_flipflags(args);
+	if (error)
+		goto out;
+	/*
+	 * Commit the flag value change and start the next trans in series
+	 */
+	error = xfs_trans_roll_inode(&args->trans, args->dp);
+	if (error)
+		goto out;
+
+	/*
+	 * Dismantle the "old" attribute/value pair by removing a "remote" value
+	 * (if it exists).
+	 */
+	xfs_attr_restore_rmt_blk(args);
+
+	if (args->rmtblkno) {
+		error = xfs_attr_rmtval_invalidate(args);
+		if (error)
+			return error;
+
+		error = xfs_attr_rmtval_remove(args);
+		if (error)
+			return error;
+	}
+
+	error = xfs_attr_node_addname_clear_incomplete(args);
+out:
 	return error;
 }
 
@@ -968,7 +1037,7 @@ xfs_attr_node_addname(
 {
 	struct xfs_da_state_blk	*blk;
 	struct xfs_inode	*dp;
-	int			retval, error;
+	int			error;
 
 	trace_xfs_attr_node_addname(args);
 
@@ -976,8 +1045,8 @@ xfs_attr_node_addname(
 	blk = &state->path.blk[state->path.active-1];
 	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
 
-	retval = xfs_attr3_leaf_add(blk->bp, state->args);
-	if (retval == -ENOSPC) {
+	error = xfs_attr3_leaf_add(blk->bp, state->args);
+	if (error == -ENOSPC) {
 		if (state->path.active == 1) {
 			/*
 			 * Its really a single leaf node, but it had
@@ -1023,88 +1092,10 @@ xfs_attr_node_addname(
 		xfs_da3_fixhashpath(state, &state->path);
 	}
 
-	/*
-	 * Kill the state structure, we're done with it and need to
-	 * allow the buffers to come back later.
-	 */
-	xfs_da_state_free(state);
-	state = NULL;
-
-	/*
-	 * Commit the leaf addition or btree split and start the next
-	 * trans in the chain.
-	 */
-	error = xfs_trans_roll_inode(&args->trans, dp);
-	if (error)
-		goto out;
-
-	/*
-	 * 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) {
-		error = xfs_attr_rmtval_set(args);
-		if (error)
-			return error;
-	}
-
-	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
-		/*
-		 * Added a "remote" value, just clear the incomplete flag.
-		 */
-		if (args->rmtblkno > 0)
-			error = xfs_attr3_leaf_clearflag(args);
-		retval = error;
-		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.
-	 */
-	error = xfs_attr3_leaf_flipflags(args);
-	if (error)
-		goto out;
-	/*
-	 * Commit the flag value change and start the next trans in series
-	 */
-	error = xfs_trans_roll_inode(&args->trans, args->dp);
-	if (error)
-		goto out;
-
-	/*
-	 * Dismantle the "old" attribute/value pair by removing a "remote" value
-	 * (if it exists).
-	 */
-	xfs_attr_restore_rmt_blk(args);
-
-	if (args->rmtblkno) {
-		error = xfs_attr_rmtval_invalidate(args);
-		if (error)
-			return error;
-
-		error = xfs_attr_rmtval_remove(args);
-		if (error)
-			return error;
-	}
-
-	error = xfs_attr_node_addname_clear_incomplete(args);
-	if (error)
-		goto out;
-	retval = 0;
 out:
 	if (state)
 		xfs_da_state_free(state);
-	if (error)
-		return error;
-	return retval;
+	return error;
 }
 
 
-- 
2.7.4

[PATCH v20 07/14] xfs: Hoist xfs_attr_leaf_addname

[Allison Henderson]

This patch hoists xfs_attr_leaf_addname into the calling function.  The
goal being to get all the code that will require state management into
the same scope. This isn't particularly aesthetic right away, but it is a
preliminary step to merging in the state machine code.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/libxfs/xfs_attr.c | 209 ++++++++++++++++++++++-------------------------
 fs/xfs/xfs_trace.h       |   1 -
 2 files changed, 96 insertions(+), 114 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index b35c742..4bbf34c 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -44,9 +44,9 @@ STATIC int xfs_attr_shortform_addname(xfs_da_args_t *args);
  * Internal routines when attribute list is one block.
  */
 STATIC int xfs_attr_leaf_get(xfs_da_args_t *args);
-STATIC int xfs_attr_leaf_addname(xfs_da_args_t *args);
 STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
 STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);
+STATIC int xfs_attr_leaf_try_add(struct xfs_da_args *args, struct xfs_buf *bp);
 
 /*
  * Internal routines when attribute list is more than one block.
@@ -291,8 +291,9 @@ xfs_attr_set_args(
 	struct xfs_da_args	*args)
 {
 	struct xfs_inode	*dp = args->dp;
+	struct xfs_buf		*bp = NULL;
 	struct xfs_da_state     *state = NULL;
-	int			error = 0;
+	int			forkoff, error = 0;
 
 	/*
 	 * If the attribute list is already in leaf format, jump straight to
@@ -307,10 +308,101 @@ xfs_attr_set_args(
 	}
 
 	if (xfs_attr_is_leaf(dp)) {
-		error = xfs_attr_leaf_addname(args);
-		if (error != -ENOSPC)
+		error = xfs_attr_leaf_try_add(args, bp);
+		if (error == -ENOSPC)
+			goto node;
+		else if (error)
+			return error;
+
+		/*
+		 * Commit the transaction that added the attr name so that
+		 * later routines can manage their own transactions.
+		 */
+		error = xfs_trans_roll_inode(&args->trans, dp);
+		if (error)
+			return error;
+
+		/*
+		 * 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) {
+			error = xfs_attr_rmtval_set(args);
+			if (error)
+				return error;
+		}
+
+		if (!(args->op_flags & XFS_DA_OP_RENAME)) {
+			/*
+			 * Added a "remote" value, just clear the incomplete
+			 *flag.
+			 */
+			if (args->rmtblkno > 0)
+				error = xfs_attr3_leaf_clearflag(args);
+
+			return error;
+		}
+
+		/*
+		 * 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.
+		 */
+
+		error = xfs_attr3_leaf_flipflags(args);
+		if (error)
+			return error;
+		/*
+		 * Commit the flag value change and start the next trans in
+		 * series.
+		 */
+		error = xfs_trans_roll_inode(&args->trans, args->dp);
+		if (error)
+			return error;
+
+		/*
+		 * Dismantle the "old" attribute/value pair by removing a
+		 * "remote" value (if it exists).
+		 */
+		xfs_attr_restore_rmt_blk(args);
+
+		if (args->rmtblkno) {
+			error = xfs_attr_rmtval_invalidate(args);
+			if (error)
+				return error;
+
+			error = xfs_attr_rmtval_remove(args);
+			if (error)
+				return error;
+		}
+
+		/*
+		 * Read in the block containing the "old" attr, then remove the
+		 * "old" attr from that block (neat, huh!)
+		 */
+		error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno,
+					   &bp);
+		if (error)
 			return error;
 
+		xfs_attr3_leaf_remove(bp, args);
+
+		/*
+		 * If the result is small enough, shrink it all into the inode.
+		 */
+		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;
+node:
 		/*
 		 * Promote the attribute list to the Btree format.
 		 */
@@ -737,115 +829,6 @@ xfs_attr_leaf_try_add(
 	return retval;
 }
 
-
-/*
- * Add a name to the leaf attribute list structure
- *
- * This leaf block cannot have a "remote" value, we only call this routine
- * if bmap_one_block() says there is only one block (ie: no remote blks).
- */
-STATIC int
-xfs_attr_leaf_addname(
-	struct xfs_da_args	*args)
-{
-	int			error, forkoff;
-	struct xfs_buf		*bp = NULL;
-	struct xfs_inode	*dp = args->dp;
-
-	trace_xfs_attr_leaf_addname(args);
-
-	error = xfs_attr_leaf_try_add(args, bp);
-	if (error)
-		return error;
-
-	/*
-	 * Commit the transaction that added the attr name so that
-	 * later routines can manage their own transactions.
-	 */
-	error = xfs_trans_roll_inode(&args->trans, dp);
-	if (error)
-		return error;
-
-	/*
-	 * 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) {
-		error = xfs_attr_rmtval_set(args);
-		if (error)
-			return error;
-	}
-
-	if (!(args->op_flags & XFS_DA_OP_RENAME)) {
-		/*
-		 * Added a "remote" value, just clear the incomplete flag.
-		 */
-		if (args->rmtblkno > 0)
-			error = xfs_attr3_leaf_clearflag(args);
-
-		return error;
-	}
-
-	/*
-	 * 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.
-	 */
-
-	error = xfs_attr3_leaf_flipflags(args);
-	if (error)
-		return error;
-	/*
-	 * Commit the flag value change and start the next trans in series.
-	 */
-	error = xfs_trans_roll_inode(&args->trans, args->dp);
-	if (error)
-		return error;
-
-	/*
-	 * Dismantle the "old" attribute/value pair by removing a "remote" value
-	 * (if it exists).
-	 */
-	xfs_attr_restore_rmt_blk(args);
-
-	if (args->rmtblkno) {
-		error = xfs_attr_rmtval_invalidate(args);
-		if (error)
-			return error;
-
-		error = xfs_attr_rmtval_remove(args);
-		if (error)
-			return error;
-	}
-
-	/*
-	 * Read in the block containing the "old" attr, then remove the "old"
-	 * attr from that block (neat, huh!)
-	 */
-	error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno,
-				   &bp);
-	if (error)
-		return error;
-
-	xfs_attr3_leaf_remove(bp, args);
-
-	/*
-	 * If the result is small enough, shrink it all into the inode.
-	 */
-	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;
-}
-
 /*
  * Return EEXIST if attr is found, or ENOATTR if not
  */
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 808ae33..3c1c830 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -1914,7 +1914,6 @@ DEFINE_ATTR_EVENT(xfs_attr_leaf_add);
 DEFINE_ATTR_EVENT(xfs_attr_leaf_add_old);
 DEFINE_ATTR_EVENT(xfs_attr_leaf_add_new);
 DEFINE_ATTR_EVENT(xfs_attr_leaf_add_work);
-DEFINE_ATTR_EVENT(xfs_attr_leaf_addname);
 DEFINE_ATTR_EVENT(xfs_attr_leaf_create);
 DEFINE_ATTR_EVENT(xfs_attr_leaf_compact);
 DEFINE_ATTR_EVENT(xfs_attr_leaf_get);
-- 
2.7.4

[PATCH v20 08/14] xfs: Hoist node transaction handling

[Allison Henderson]

This patch basically hoists the node transaction handling around the
leaf code we just hoisted.  This will helps setup this area for the
state machine since the goto is easily replaced with a state since it
ends with a transaction roll.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
---
 fs/xfs/libxfs/xfs_attr.c | 55 +++++++++++++++++++++++++-----------------------
 1 file changed, 29 insertions(+), 26 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 4bbf34c..812dd1a 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -309,10 +309,36 @@ xfs_attr_set_args(
 
 	if (xfs_attr_is_leaf(dp)) {
 		error = xfs_attr_leaf_try_add(args, bp);
-		if (error == -ENOSPC)
+		if (error == -ENOSPC) {
+			/*
+			 * Promote the attribute list to the Btree format.
+			 */
+			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.
+			 */
+			error = xfs_defer_finish(&args->trans);
+			if (error)
+				return error;
+
+			/*
+			 * Commit the current trans (including the inode) and
+			 * start a new one.
+			 */
+			error = xfs_trans_roll_inode(&args->trans, dp);
+			if (error)
+				return error;
+
 			goto node;
-		else if (error)
+		} else if (error) {
 			return error;
+		}
 
 		/*
 		 * Commit the transaction that added the attr name so that
@@ -402,32 +428,9 @@ xfs_attr_set_args(
 			/* bp is gone due to xfs_da_shrink_inode */
 
 		return error;
+	}
 node:
-		/*
-		 * Promote the attribute list to the Btree format.
-		 */
-		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.
-		 */
-		error = xfs_defer_finish(&args->trans);
-		if (error)
-			return error;
 
-		/*
-		 * Commit the current trans (including the inode) and
-		 * start a new one.
-		 */
-		error = xfs_trans_roll_inode(&args->trans, dp);
-		if (error)
-			return error;
-	}
 
 	do {
 		error = xfs_attr_node_addname_find_attr(args, &state);
-- 
2.7.4

[PATCH v20 09/14] xfs: Add delay ready attr remove routines

[Allison Henderson]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=yes, Size: 19804 bytes --]

This patch modifies the attr remove routines to be delay ready. This
means they no longer roll or commit transactions, but instead return
-EAGAIN to have the calling routine roll and refresh the transaction. In
this series, xfs_attr_remove_args is merged with
xfs_attr_node_removename become a new function, xfs_attr_remove_iter.
This new version uses a sort of state machine like switch to keep track
of where it was when EAGAIN was returned. A new version of
xfs_attr_remove_args consists of a simple loop to refresh the
transaction until the operation is completed. A new XFS_DAC_DEFER_FINISH
flag is used to finish the transaction where ever the existing code used
to.

Calls to xfs_attr_rmtval_remove are replaced with the delay ready
version __xfs_attr_rmtval_remove. We will rename
__xfs_attr_rmtval_remove back to xfs_attr_rmtval_remove when we are
done.

xfs_attr_rmtval_remove itself is still in use by the set routines (used
during a rename).  For reasons of preserving existing function, we
modify xfs_attr_rmtval_remove to call xfs_defer_finish when the flag is
set.  Similar to how xfs_attr_remove_args does here.  Once we transition
the set routines to be delay ready, xfs_attr_rmtval_remove is no longer
used and will be removed.

This patch also adds a new struct xfs_delattr_context, which we will use
to keep track of the current state of an attribute operation. The new
xfs_delattr_state enum is used to track various operations that are in
progress so that we know not to repeat them, and resume where we left
off before EAGAIN was returned to cycle out the transaction. Other
members take the place of local variables that need to retain their
values across multiple function calls.  See xfs_attr.h for a more
detailed diagram of the states.

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/libxfs/xfs_attr.c        | 223 +++++++++++++++++++++++++++++-----------
 fs/xfs/libxfs/xfs_attr.h        | 131 +++++++++++++++++++++++
 fs/xfs/libxfs/xfs_attr_leaf.c   |   2 +-
 fs/xfs/libxfs/xfs_attr_remote.c |  53 ++++++----
 fs/xfs/libxfs/xfs_attr_remote.h |   2 +-
 fs/xfs/xfs_attr_inactive.c      |   2 +-
 6 files changed, 327 insertions(+), 86 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 812dd1a..513d9ca 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -57,7 +57,6 @@ STATIC int xfs_attr_node_addname(struct xfs_da_args *args,
 				 struct xfs_da_state *state);
 STATIC int xfs_attr_node_addname_find_attr(struct xfs_da_args *args,
 				 struct xfs_da_state **state);
-STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
 STATIC int xfs_attr_node_addname_clear_incomplete(struct xfs_da_args *args);
 STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
 				 struct xfs_da_state **state);
@@ -241,6 +240,31 @@ xfs_attr_is_shortform(
 		ip->i_afp->if_nextents == 0);
 }
 
+/*
+ * Checks to see if a delayed attribute transaction should be rolled.  If so,
+ * transaction is finished or rolled as needed.
+ */
+int
+xfs_attr_trans_roll(
+	struct xfs_delattr_context	*dac)
+{
+	struct xfs_da_args		*args = dac->da_args;
+	int				error;
+
+	if (dac->flags & XFS_DAC_DEFER_FINISH) {
+		/*
+		 * The caller wants us to finish all the deferred ops so that we
+		 * avoid pinning the log tail with a large number of deferred
+		 * ops.
+		 */
+		dac->flags &= ~XFS_DAC_DEFER_FINISH;
+		error = xfs_defer_finish(&args->trans);
+	} else
+		error = xfs_trans_roll_inode(&args->trans, args->dp);
+
+	return error;
+}
+
 STATIC int
 xfs_attr_set_fmt(
 	struct xfs_da_args	*args)
@@ -544,16 +568,25 @@ xfs_has_attr(
  */
 int
 xfs_attr_remove_args(
-	struct xfs_da_args      *args)
+	struct xfs_da_args	*args)
 {
-	if (!xfs_inode_hasattr(args->dp))
-		return -ENOATTR;
+	int				error;
+	struct xfs_delattr_context	dac = {
+		.da_args	= args,
+	};
 
-	if (args->dp->i_afp->if_format == XFS_DINODE_FMT_LOCAL)
-		return xfs_attr_shortform_remove(args);
-	if (xfs_attr_is_leaf(args->dp))
-		return xfs_attr_leaf_removename(args);
-	return xfs_attr_node_removename(args);
+	do {
+		error = xfs_attr_remove_iter(&dac);
+		if (error != -EAGAIN)
+			break;
+
+		error = xfs_attr_trans_roll(&dac);
+		if (error)
+			return error;
+
+	} while (true);
+
+	return error;
 }
 
 /*
@@ -1197,14 +1230,16 @@ xfs_attr_leaf_mark_incomplete(
  */
 STATIC
 int xfs_attr_node_removename_setup(
-	struct xfs_da_args	*args,
-	struct xfs_da_state	**state)
+	struct xfs_delattr_context	*dac)
 {
-	int			error;
+	struct xfs_da_args		*args = dac->da_args;
+	struct xfs_da_state		**state = &dac->da_state;
+	int				error;
 
 	error = xfs_attr_node_hasname(args, state);
 	if (error != -EEXIST)
 		return error;
+	error = 0;
 
 	ASSERT((*state)->path.blk[(*state)->path.active - 1].bp != NULL);
 	ASSERT((*state)->path.blk[(*state)->path.active - 1].magic ==
@@ -1213,12 +1248,15 @@ int xfs_attr_node_removename_setup(
 	if (args->rmtblkno > 0) {
 		error = xfs_attr_leaf_mark_incomplete(args, *state);
 		if (error)
-			return error;
+			goto out;
 
-		return xfs_attr_rmtval_invalidate(args);
+		error = xfs_attr_rmtval_invalidate(args);
 	}
+out:
+	if (error)
+		xfs_da_state_free(*state);
 
-	return 0;
+	return error;
 }
 
 STATIC int
@@ -1241,70 +1279,133 @@ xfs_attr_node_remove_name(
 }
 
 /*
- * Remove a name from a B-tree attribute list.
+ * 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.
  */
-STATIC int
-xfs_attr_node_removename(
-	struct xfs_da_args	*args)
+int
+xfs_attr_remove_iter(
+	struct xfs_delattr_context	*dac)
 {
-	struct xfs_da_state	*state;
-	int			retval, error;
-	struct xfs_inode	*dp = args->dp;
+	struct xfs_da_args		*args = dac->da_args;
+	struct xfs_da_state		*state = dac->da_state;
+	int				retval, error;
+	struct xfs_inode		*dp = args->dp;
 
 	trace_xfs_attr_node_removename(args);
 
-	error = xfs_attr_node_removename_setup(args, &state);
-	if (error)
-		goto out;
+	switch (dac->dela_state) {
+	case XFS_DAS_UNINIT:
+		if (!xfs_inode_hasattr(dp))
+			return -ENOATTR;
 
-	/*
-	 * 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) {
-		error = xfs_attr_rmtval_remove(args);
-		if (error)
-			goto out;
+		/*
+		 * 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_shortform_remove(args);
+
+		if (xfs_attr_is_leaf(dp))
+			return xfs_attr_leaf_removename(args);
 
 		/*
-		 * Refill the state structure with buffers, the prior calls
-		 * released our buffers.
+		 * Node format may require transaction rolls. Set up the
+		 * state context and fall into the state machine.
 		 */
-		error = xfs_attr_refillstate(state);
-		if (error)
-			goto out;
-	}
-	retval = xfs_attr_node_remove_name(args, state);
+		if (!dac->da_state) {
+			error = xfs_attr_node_removename_setup(dac);
+			if (error)
+				return error;
+			state = dac->da_state;
+		}
+
+		/* fallthrough */
+	case XFS_DAS_RMTBLK:
+		dac->dela_state = XFS_DAS_RMTBLK;
 
-	/*
-	 * Check to see if the tree needs to be collapsed.
-	 */
-	if (retval && (state->path.active > 1)) {
-		error = xfs_da3_join(state);
-		if (error)
-			goto out;
-		error = xfs_defer_finish(&args->trans);
-		if (error)
-			goto out;
 		/*
-		 * Commit the Btree join operation and start a new trans.
+		 * 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.
 		 */
-		error = xfs_trans_roll_inode(&args->trans, dp);
-		if (error)
-			goto out;
-	}
+		if (args->rmtblkno > 0) {
+			/*
+			 * May return -EAGAIN. Roll and repeat until all remote
+			 * blocks are removed.
+			 */
+			error = __xfs_attr_rmtval_remove(dac);
+			if (error == -EAGAIN)
+				return error;
+			else if (error)
+				goto out;
 
-	/*
-	 * If the result is small enough, push it all into the inode.
-	 */
-	if (xfs_attr_is_leaf(dp))
-		error = xfs_attr_node_shrink(args, state);
+			/*
+			 * 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;
+			dac->dela_state = XFS_DAS_RM_NAME;
+			dac->flags |= XFS_DAC_DEFER_FINISH;
+			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 (dac->dela_state == XFS_DAS_RM_NAME) {
+			error = xfs_attr_refillstate(state);
+			if (error)
+				goto out;
+		}
 
+		retval = xfs_attr_node_remove_name(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;
+
+			dac->flags |= XFS_DAC_DEFER_FINISH;
+			dac->dela_state = XFS_DAS_RM_SHRINK;
+			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);
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index 2b1f619..1267ea8 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -74,6 +74,133 @@ struct xfs_attr_list_context {
 };
 
 
+/*
+ * ========================================================================
+ * Structure used to pass context around among the delayed routines.
+ * ========================================================================
+ */
+
+/*
+ * Below is a state machine diagram for attr remove operations. The  XFS_DAS_*
+ * states indicate places where the function would return -EAGAIN, and then
+ * immediately resume from after being called by the calling function. States
+ * marked as a "subroutine state" indicate that they belong to a subroutine, and
+ * so the calling function needs to pass them back to that subroutine to allow
+ * it to finish where it left off. But they otherwise do not have a role in the
+ * calling function other than just passing through.
+ *
+ * xfs_attr_remove_iter()
+ *              │
+ *              v
+ *        have attr to remove? ──n──> done
+ *              │
+ *              y
+ *              │
+ *              v
+ *        are we short form? ──y──> xfs_attr_shortform_remove ──> done
+ *              │
+ *              n
+ *              │
+ *              V
+ *        are we leaf form? ──y──> xfs_attr_leaf_removename ──> done
+ *              │
+ *              n
+ *              │
+ *              V
+ *   ┌── need to setup state?
+ *   │          │
+ *   n          y
+ *   │          │
+ *   │          v
+ *   │ find attr and get state
+ *   │ attr has remote blks? ──n─┐
+ *   │          │                v
+ *   │          │         find and invalidate
+ *   │          y         the remote blocks.
+ *   │          │         mark attr incomplete
+ *   │          ├────────────────┘
+ *   └──────────┤
+ *              │
+ *              v
+ *   Have remote blks to remove? ───y─────┐
+ *              │        ^          remove the blks
+ *              │        │                │
+ *              │        │                v
+ *              │  XFS_DAS_RMTBLK <─n── done?
+ *              │  re-enter with          │
+ *              │  one less blk to        y
+ *              │      remove             │
+ *              │                         V
+ *              │                  refill the state
+ *              n                         │
+ *              │                         v
+ *              │                   XFS_DAS_RM_NAME
+ *              │                         │
+ *              ├─────────────────────────┘
+ *              │
+ *              v
+ *       remove leaf and
+ *       update hash with
+ *   xfs_attr_node_remove_cleanup
+ *              │
+ *              v
+ *           need to
+ *        shrink tree? ─n─┐
+ *              │         │
+ *              y         │
+ *              │         │
+ *              v         │
+ *          join leaf     │
+ *              │         │
+ *              v         │
+ *      XFS_DAS_RM_SHRINK │
+ *              │         │
+ *              v         │
+ *       do the shrink    │
+ *              │         │
+ *              v         │
+ *          free state <──┘
+ *              │
+ *              v
+ *            done
+ *
+ */
+
+/*
+ * Enum values for xfs_delattr_context.da_state
+ *
+ * These values are used by delayed attribute operations to keep track  of where
+ * they were before they returned -EAGAIN.  A return code of -EAGAIN signals the
+ * calling function to roll the transaction, and then call the subroutine to
+ * finish the operation.  The enum is then used by the subroutine to jump back
+ * 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 */
+};
+
+/*
+ * Defines for xfs_delattr_context.flags
+ */
+#define XFS_DAC_DEFER_FINISH		0x01 /* finish the transaction */
+
+/*
+ * Context used for keeping track of delayed attribute operations
+ */
+struct xfs_delattr_context {
+	struct xfs_da_args      *da_args;
+
+	/* Used in xfs_attr_node_removename to roll through removing blocks */
+	struct xfs_da_state     *da_state;
+
+	/* Used to keep track of current state of delayed operation */
+	unsigned int            flags;
+	enum xfs_delattr_state  dela_state;
+};
+
 /*========================================================================
  * Function prototypes for the kernel.
  *========================================================================*/
@@ -92,6 +219,10 @@ int xfs_attr_set(struct xfs_da_args *args);
 int xfs_attr_set_args(struct xfs_da_args *args);
 int xfs_has_attr(struct xfs_da_args *args);
 int xfs_attr_remove_args(struct xfs_da_args *args);
+int xfs_attr_remove_iter(struct xfs_delattr_context *dac);
+int xfs_attr_trans_roll(struct xfs_delattr_context *dac);
 bool xfs_attr_namecheck(const void *name, size_t length);
+void xfs_delattr_context_init(struct xfs_delattr_context *dac,
+			      struct xfs_da_args *args);
 
 #endif	/* __XFS_ATTR_H__ */
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 556184b..d97de20 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -19,8 +19,8 @@
 #include "xfs_bmap_btree.h"
 #include "xfs_bmap.h"
 #include "xfs_attr_sf.h"
-#include "xfs_attr_remote.h"
 #include "xfs_attr.h"
+#include "xfs_attr_remote.h"
 #include "xfs_attr_leaf.h"
 #include "xfs_error.h"
 #include "xfs_trace.h"
diff --git a/fs/xfs/libxfs/xfs_attr_remote.c b/fs/xfs/libxfs/xfs_attr_remote.c
index 48d8e9c..c26193b 100644
--- a/fs/xfs/libxfs/xfs_attr_remote.c
+++ b/fs/xfs/libxfs/xfs_attr_remote.c
@@ -674,10 +674,12 @@ xfs_attr_rmtval_invalidate(
  */
 int
 xfs_attr_rmtval_remove(
-	struct xfs_da_args      *args)
+	struct xfs_da_args		*args)
 {
-	int			error;
-	int			retval;
+	int				error;
+	struct xfs_delattr_context	dac  = {
+		.da_args	= args,
+	};
 
 	trace_xfs_attr_rmtval_remove(args);
 
@@ -685,31 +687,30 @@ xfs_attr_rmtval_remove(
 	 * Keep de-allocating extents until the remote-value region is gone.
 	 */
 	do {
-		retval = __xfs_attr_rmtval_remove(args);
-		if (retval && retval != -EAGAIN)
-			return retval;
+		error = __xfs_attr_rmtval_remove(&dac);
+		if (error && error != -EAGAIN)
+			break;
 
-		/*
-		 * Close out trans and start the next one in the chain.
-		 */
-		error = xfs_trans_roll_inode(&args->trans, args->dp);
+		error = xfs_attr_trans_roll(&dac);
 		if (error)
 			return error;
-	} while (retval == -EAGAIN);
+	} while (true);
 
-	return 0;
+	return error;
 }
 
 /*
  * Remove the value associated with an attribute by deleting the out-of-line
- * buffer that it is stored on. Returns EAGAIN for the caller to refresh the
- * transaction and re-call the function
+ * buffer that it is stored on. Returns -EAGAIN for the caller to refresh the
+ * transaction and re-call the function.  Callers should keep calling this
+ * routine until it returns something other than -EAGAIN.
  */
 int
 __xfs_attr_rmtval_remove(
-	struct xfs_da_args	*args)
+	struct xfs_delattr_context	*dac)
 {
-	int			error, done;
+	struct xfs_da_args		*args = dac->da_args;
+	int				error, done;
 
 	/*
 	 * Unmap value blocks for this attr.
@@ -719,12 +720,20 @@ __xfs_attr_rmtval_remove(
 	if (error)
 		return error;
 
-	error = xfs_defer_finish(&args->trans);
-	if (error)
-		return error;
-
-	if (!done)
+	/*
+	 * We don't need an explicit state here to pick up where we left off. We
+	 * can figure it out using the !done return code. The actual value of
+	 * attr->xattri_dela_state may be some value reminiscent of the calling
+	 * function, but it's value is irrelevant with in the context of this
+	 * function. Once we are done here, the next state is set as needed by
+	 * the parent
+	 */
+	if (!done) {
+		dac->flags |= XFS_DAC_DEFER_FINISH;
 		return -EAGAIN;
+	}
 
-	return error;
+	args->rmtblkno = 0;
+	args->rmtblkcnt = 0;
+	return 0;
 }
diff --git a/fs/xfs/libxfs/xfs_attr_remote.h b/fs/xfs/libxfs/xfs_attr_remote.h
index 9eee615..002fd30 100644
--- a/fs/xfs/libxfs/xfs_attr_remote.h
+++ b/fs/xfs/libxfs/xfs_attr_remote.h
@@ -14,5 +14,5 @@ int xfs_attr_rmtval_remove(struct xfs_da_args *args);
 int xfs_attr_rmtval_stale(struct xfs_inode *ip, struct xfs_bmbt_irec *map,
 		xfs_buf_flags_t incore_flags);
 int xfs_attr_rmtval_invalidate(struct xfs_da_args *args);
-int __xfs_attr_rmtval_remove(struct xfs_da_args *args);
+int __xfs_attr_rmtval_remove(struct xfs_delattr_context *dac);
 #endif /* __XFS_ATTR_REMOTE_H__ */
diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c
index bfad669..aaa7e66 100644
--- a/fs/xfs/xfs_attr_inactive.c
+++ b/fs/xfs/xfs_attr_inactive.c
@@ -15,10 +15,10 @@
 #include "xfs_da_format.h"
 #include "xfs_da_btree.h"
 #include "xfs_inode.h"
+#include "xfs_attr.h"
 #include "xfs_attr_remote.h"
 #include "xfs_trans.h"
 #include "xfs_bmap.h"
-#include "xfs_attr.h"
 #include "xfs_attr_leaf.h"
 #include "xfs_quota.h"
 #include "xfs_dir2.h"
-- 
2.7.4