[PATCH 16/18 v2] xfs: use XFS_DA_OP flags in deferred attr ops

From: Dave Chinner <david@fromorbit.com>
To: linux-xfs@vger.kernel.org
Subject: [PATCH 16/18 v2] xfs: use XFS_DA_OP flags in deferred attr ops
Date: Wed, 11 May 2022 08:20:15 +1000	[thread overview]
Message-ID: <20220510222015.GV1098723@dread.disaster.area> (raw)
In-Reply-To: <20220509004138.762556-17-david@fromorbit.com>

From: Dave Chinner <dchinner@redhat.com>

We currently store the high level attr operation in
args->attr_flags. This falgs are what the VFS is telling us to do,
but don't necessarily match what we are doing in the low level
modification state machine. e.g. XATTR_REPLACE implies both
XFS_DA_OP_ADDNAME and XFS_DA_OP_RENAME because it is doing both a
remove and adding a new attr.

However, deep in the individual state machine operations, we check
errors against this high level VFS op flags, not the low level
XFS_DA_OP flags. Indeed, we don't even have a low level flag for
a REMOVE operation, so the only way we know we are doing a remove
is the complete absence of XATTR_REPLACE, XATTR_CREATE,
XFS_DA_OP_ADDNAME and XFS_DA_OP_RENAME. And because there are other
flags in these fields, this is a pain to check if we need to.

As the XFS_DA_OP flags are only needed once the deferred operations
are set up, set these flags appropriately when we set the initial
operation state. We also introduce a XFS_DA_OP_REMOVE flag to make
it easy to know that we are doing a remove operation.

With these, we can remove the use of XATTR_REPLACE and XATTR_CREATE
in low level lookup operations, and manipulate the low level flags
according to the low level context that is operating. e.g. log
recovery does not have a VFS xattr operation state to copy into
args->attr_flags, and the low level state machine ops we do for
recovery do not match the high level VFS operations that were in
progress when the system failed...

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
Version 2 (now that vger has finally got this to me after 2 days):
- fixed bug by that removed clearing remote block values after save
  for node format blocks. Clearing is now done by
  xfs_attr_save_rmt_blk() for both callers.

 fs/xfs/libxfs/xfs_attr.c      | 136 +++++++++++++++++++++++-------------------
 fs/xfs/libxfs/xfs_attr.h      |   3 +
 fs/xfs/libxfs/xfs_attr_leaf.c |   2 +-
 fs/xfs/libxfs/xfs_da_btree.h  |   8 ++-
 4 files changed, 83 insertions(+), 66 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 8be76f8d11c5..a36364b27aa1 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -467,7 +467,7 @@ 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)
+	else if (args->op_flags & XFS_DA_OP_REPLACE)
 		xfs_attr_dela_state_set_replace(attr, XFS_DAS_LEAF_REPLACE);
 	else
 		attr->xattri_dela_state = XFS_DAS_DONE;
@@ -512,7 +512,7 @@ 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)
+	else if (args->op_flags & XFS_DA_OP_REPLACE)
 		xfs_attr_dela_state_set_replace(attr, XFS_DAS_NODE_REPLACE);
 	else
 		attr->xattri_dela_state = XFS_DAS_DONE;
@@ -548,7 +548,7 @@ xfs_attr_rmtval_alloc(
 		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->op_flags & XFS_DA_OP_REPLACE)) {
 		error = xfs_attr3_leaf_clearflag(args);
 		attr->xattri_dela_state = XFS_DAS_DONE;
 	} else {
@@ -967,8 +967,6 @@ xfs_attr_set(
 
 	if (args->value) {
 		XFS_STATS_INC(mp, xs_attr_set);
-
-		args->op_flags |= XFS_DA_OP_ADDNAME;
 		args->total = xfs_attr_calc_size(args, &local);
 
 		/*
@@ -1126,28 +1124,41 @@ static inline int xfs_attr_sf_totsize(struct xfs_inode *dp)
  * Add a name to the shortform attribute list structure
  * This is the external routine.
  */
-STATIC int
-xfs_attr_shortform_addname(xfs_da_args_t *args)
+static int
+xfs_attr_shortform_addname(
+	struct xfs_da_args	*args)
 {
-	int newsize, forkoff, retval;
+	int			newsize, forkoff;
+	int			error;
 
 	trace_xfs_attr_sf_addname(args);
 
-	retval = xfs_attr_shortform_lookup(args);
-	if (retval == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
-		return retval;
-	if (retval == -EEXIST) {
-		if (args->attr_flags & XATTR_CREATE)
-			return retval;
-		retval = xfs_attr_sf_removename(args);
-		if (retval)
-			return retval;
+	error = xfs_attr_shortform_lookup(args);
+	switch (error) {
+	case -ENOATTR:
+		if (args->op_flags & XFS_DA_OP_REPLACE)
+			return error;
+		break;
+	case -EEXIST:
+		if (!(args->op_flags & XFS_DA_OP_REPLACE))
+			return error;
+
+		error = xfs_attr_sf_removename(args);
+		if (error)
+			return error;
+
 		/*
-		 * Since we have removed the old attr, clear ATTR_REPLACE so
-		 * that the leaf format add routine won't trip over the attr
-		 * not being around.
+		 * Since we have removed the old attr, clear XFS_DA_OP_REPLACE
+		 * so that the new attr doesn't fit in shortform format, the
+		 * leaf format add routine won't trip over the attr not being
+		 * around.
 		 */
-		args->attr_flags &= ~XATTR_REPLACE;
+		args->op_flags &= ~XFS_DA_OP_REPLACE;
+		break;
+	case 0:
+		break;
+	default:
+		return error;
 	}
 
 	if (args->namelen >= XFS_ATTR_SF_ENTSIZE_MAX ||
@@ -1170,8 +1181,8 @@ xfs_attr_shortform_addname(xfs_da_args_t *args)
  * External routines when attribute list is one block
  *========================================================================*/
 
-/* Store info about a remote block */
-STATIC void
+/* Save the current remote block info and clear the current pointers. */
+static void
 xfs_attr_save_rmt_blk(
 	struct xfs_da_args	*args)
 {
@@ -1180,10 +1191,13 @@ xfs_attr_save_rmt_blk(
 	args->rmtblkno2 = args->rmtblkno;
 	args->rmtblkcnt2 = args->rmtblkcnt;
 	args->rmtvaluelen2 = args->rmtvaluelen;
+	args->rmtblkno = 0;
+	args->rmtblkcnt = 0;
+	args->rmtvaluelen = 0;
 }
 
 /* Set stored info about a remote block */
-STATIC void
+static void
 xfs_attr_restore_rmt_blk(
 	struct xfs_da_args	*args)
 {
@@ -1229,28 +1243,27 @@ xfs_attr_leaf_try_add(
 	 * 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 (error == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
-		goto out_brelse;
-	if (error == -EEXIST) {
-		if (args->attr_flags & XATTR_CREATE)
+	switch (error) {
+	case -ENOATTR:
+		if (args->op_flags & XFS_DA_OP_REPLACE)
+			goto out_brelse;
+		break;
+	case -EEXIST:
+		if (!(args->op_flags & XFS_DA_OP_REPLACE))
 			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);
-
 		/*
-		 * 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.
 		 */
-		args->rmtblkno = 0;
-		args->rmtblkcnt = 0;
-		args->rmtvaluelen = 0;
+		xfs_attr_save_rmt_blk(args);
+		break;
+	case 0:
+		break;
+	default:
+		goto out_brelse;
 	}
 
 	return xfs_attr3_leaf_add(bp, args);
@@ -1389,46 +1402,45 @@ xfs_attr_node_hasname(
 
 STATIC int
 xfs_attr_node_addname_find_attr(
-	 struct xfs_attr_item		*attr)
+	 struct xfs_attr_item	*attr)
 {
-	struct xfs_da_args		*args = attr->xattri_da_args;
-	int				retval;
+	struct xfs_da_args	*args = attr->xattri_da_args;
+	int			error;
 
 	/*
 	 * Search to see if name already exists, and get back a pointer
 	 * to where it should go.
 	 */
-	retval = xfs_attr_node_hasname(args, &attr->xattri_da_state);
-	if (retval != -ENOATTR && retval != -EEXIST)
-		goto error;
-
-	if (retval == -ENOATTR && (args->attr_flags & XATTR_REPLACE))
-		goto error;
-	if (retval == -EEXIST) {
-		if (args->attr_flags & XATTR_CREATE)
+	error = xfs_attr_node_hasname(args, &attr->xattri_da_state);
+	switch (error) {
+	case -ENOATTR:
+		if (args->op_flags & XFS_DA_OP_REPLACE)
+			goto error;
+		break;
+	case -EEXIST:
+		if (!(args->op_flags & XFS_DA_OP_REPLACE))
 			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);
 
+		trace_xfs_attr_node_replace(args);
 		/*
-		 * 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.
 		 */
-		args->rmtblkno = 0;
-		args->rmtblkcnt = 0;
-		args->rmtvaluelen = 0;
+		xfs_attr_save_rmt_blk(args);
+		break;
+	case 0:
+		break;
+	default:
+		goto error;
 	}
 
 	return 0;
 error:
 	if (attr->xattri_da_state)
 		xfs_da_state_free(attr->xattri_da_state);
-	return retval;
+	return error;
 }
 
 /*
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index 6bef522533a4..e93efc8b11cd 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -584,6 +584,7 @@ xfs_attr_is_shortform(
 static inline enum xfs_delattr_state
 xfs_attr_init_add_state(struct xfs_da_args *args)
 {
+	args->op_flags |= XFS_DA_OP_ADDNAME;
 	if (!args->dp->i_afp)
 		return XFS_DAS_DONE;
 	if (xfs_attr_is_shortform(args->dp))
@@ -596,6 +597,7 @@ xfs_attr_init_add_state(struct xfs_da_args *args)
 static inline enum xfs_delattr_state
 xfs_attr_init_remove_state(struct xfs_da_args *args)
 {
+	args->op_flags |= XFS_DA_OP_REMOVE;
 	if (xfs_attr_is_shortform(args->dp))
 		return XFS_DAS_SF_REMOVE;
 	if (xfs_attr_is_leaf(args->dp))
@@ -606,6 +608,7 @@ xfs_attr_init_remove_state(struct xfs_da_args *args)
 static inline enum xfs_delattr_state
 xfs_attr_init_replace_state(struct xfs_da_args *args)
 {
+	args->op_flags |= XFS_DA_OP_ADDNAME | XFS_DA_OP_REPLACE;
 	return xfs_attr_init_add_state(args);
 }
 
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index e90bfd9d7551..53d02ce9ed78 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -1492,7 +1492,7 @@ xfs_attr3_leaf_add_work(
 	entry->flags = args->attr_filter;
 	if (tmp)
 		entry->flags |= XFS_ATTR_LOCAL;
-	if (args->op_flags & XFS_DA_OP_RENAME) {
+	if (args->op_flags & XFS_DA_OP_REPLACE) {
 		if (!xfs_has_larp(mp))
 			entry->flags |= XFS_ATTR_INCOMPLETE;
 		if ((args->blkno2 == args->blkno) &&
diff --git a/fs/xfs/libxfs/xfs_da_btree.h b/fs/xfs/libxfs/xfs_da_btree.h
index deb368d041e3..468ca70cd35d 100644
--- a/fs/xfs/libxfs/xfs_da_btree.h
+++ b/fs/xfs/libxfs/xfs_da_btree.h
@@ -85,19 +85,21 @@ typedef struct xfs_da_args {
  * Operation flags:
  */
 #define XFS_DA_OP_JUSTCHECK	(1u << 0) /* check for ok with no space */
-#define XFS_DA_OP_RENAME	(1u << 1) /* this is an atomic rename op */
+#define XFS_DA_OP_REPLACE	(1u << 1) /* this is an atomic replace op */
 #define XFS_DA_OP_ADDNAME	(1u << 2) /* this is an add operation */
 #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_REMOVE	(1u << 6) /* this is a remove operation */
 
 #define XFS_DA_OP_FLAGS \
 	{ XFS_DA_OP_JUSTCHECK,	"JUSTCHECK" }, \
-	{ XFS_DA_OP_RENAME,	"RENAME" }, \
+	{ XFS_DA_OP_REPLACE,	"REPLACE" }, \
 	{ XFS_DA_OP_ADDNAME,	"ADDNAME" }, \
 	{ XFS_DA_OP_OKNOENT,	"OKNOENT" }, \
 	{ XFS_DA_OP_CILOOKUP,	"CILOOKUP" }, \
-	{ XFS_DA_OP_NOTIME,	"NOTIME" }
+	{ XFS_DA_OP_NOTIME,	"NOTIME" }, \
+	{ XFS_DA_OP_REMOVE,	"REMOVE" }
 
 /*
  * Storage for holding state during Btree searches and split/join ops.
Dave Chinner
david@fromorbit.com
