diff mbox series

[v8,38/39] xfsprogs: Add delay ready attr set routines

Message ID 20200403220958.4944-39-allison.henderson@oracle.com (mailing list archive)
State Superseded
Headers show
Series xfsprogs: Delay Ready Attributes | expand

Commit Message

Allison Henderson April 3, 2020, 10:09 p.m. UTC
This patch modifies the attr set 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_set_args has become xfs_attr_set_iter, which uses a
state machine like switch to keep track of where it was when EAGAIN was
returned.

Two new helper functions have been added: xfs_attr_rmtval_set_init and
xfs_attr_rmtval_set_blk.  They provide a subset of logic similar to
xfs_attr_rmtval_set, but they store the current block in the delay attr
context to allow the caller to roll the transaction between allocations.
This helps to simplify and consolidate code used by
xfs_attr_leaf_addname and xfs_attr_node_addname. xfs_attr_set_args has
now become a simple loop to refresh the transaction until the operation
is completed.  Lastly, xfs_attr_rmtval_remove is no longer used, and is
removed.

Below is a state machine diagram for attr set operations. The XFS_DAS_*
states indicate places where the function would return -EAGAIN, and then
immediately resume from after being recalled 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_set_iter()
                 │
                 v
           need to upgrade
          from sf to leaf? ──n─┐
                 │             │
                 y             │
                 │             │
                 V             │
          XFS_DAS_ADD_LEAF     │
                 │             │
                 v             │
  ┌──────n── fork has   <──────┘
  │         only 1 blk?
  │              │
  │              y
  │              │
  │              v
  │     xfs_attr_leaf_try_add()
  │              │
  │              v
  │          had enough
  ├──────n──   space?
  │              │
  │              y
  │              │
  │              v
  │      XFS_DAS_FOUND_LBLK  ──┐
  │                            │
  │      XFS_DAS_FLIP_LFLAG  ──┤
  │      (subroutine state)    │
  │                            │
  │      XFS_DAS_ALLOC_LEAF  ──┤
  │      (subroutine state)    │
  │                            └─>xfs_attr_leaf_addname()
  │                                              │
  │                                              v
  │                                ┌─────n──  need to
  │                                │        alloc blks?
  │                                │             │
  │                                │             y
  │                                │             │
  │                                │             v
  │                                │  ┌─>XFS_DAS_ALLOC_LEAF
  │                                │  │          │
  │                                │  │          v
  │                                │  └──y── need to alloc
  │                                │         more blocks?
  │                                │             │
  │                                │             n
  │                                │             │
  │                                │             v
  │                                │          was this
  │                                └────────> a rename? ──n─┐
  │                                              │          │
  │                                              y          │
  │                                              │          │
  │                                              v          │
  │                                        flip incomplete  │
  │                                            flag         │
  │                                              │          │
  │                                              v          │
  │                                      XFS_DAS_FLIP_LFLAG │
  │                                              │          │
  │                                              v          │
  │                                            remove       │
  │                        XFS_DAS_RM_LBLK ─> old name      │
  │                                 ^            │          │
  │                                 │            v          │
  │                                 └──────y── more to      │
  │                                            remove       │
  │                                              │          │
  │                                              n          │
  │                                              │          │
  │                                              v          │
  │                                             done <──────┘
  └────> XFS_DAS_LEAF_TO_NODE ─┐
                               │
         XFS_DAS_FOUND_NBLK  ──┤
         (subroutine state)    │
                               │
         XFS_DAS_ALLOC_NODE  ──┤
         (subroutine state)    │
                               │
         XFS_DAS_FLIP_NFLAG  ──┤
         (subroutine state)    │
                               │
                               └─>xfs_attr_node_addname()
                                                 │
                                                 v
                                         find space to store
                                        attr. Split if needed
                                                 │
                                                 v
                                         XFS_DAS_FOUND_NBLK
                                                 │
                                                 v
                                   ┌─────n──  need to
                                   │        alloc blks?
                                   │             │
                                   │             y
                                   │             │
                                   │             v
                                   │  ┌─>XFS_DAS_ALLOC_NODE
                                   │  │          │
                                   │  │          v
                                   │  └──y── need to alloc
                                   │         more blocks?
                                   │             │
                                   │             n
                                   │             │
                                   │             v
                                   │          was this
                                   └────────> a rename? ──n─┐
                                                 │          │
                                                 y          │
                                                 │          │
                                                 v          │
                                           flip incomplete  │
                                               flag         │
                                                 │          │
                                                 v          │
                                         XFS_DAS_FLIP_NFLAG │
                                                 │          │
                                                 v          │
                                               remove       │
                           XFS_DAS_RM_NBLK ─> old name      │
                                    ^            │          │
                                    │            v          │
                                    └──────y── more to      │
                                               remove       │
                                                 │          │
                                                 n          │
                                                 │          │
                                                 v          │
                                                done <──────┘

Signed-off-by: Allison Collins <allison.henderson@oracle.com>
---
 include/libxfs.h         |   1 +
 libxfs/xfs_attr.c        | 384 ++++++++++++++++++++++++++++++++---------------
 libxfs/xfs_attr.h        |  16 ++
 libxfs/xfs_attr_leaf.c   |   1 +
 libxfs/xfs_attr_remote.c | 111 ++++++++------
 libxfs/xfs_attr_remote.h |   4 +
 6 files changed, 351 insertions(+), 166 deletions(-)
diff mbox series

Patch

diff --git a/include/libxfs.h b/include/libxfs.h
index 1244783..33ec7f1 100644
--- a/include/libxfs.h
+++ b/include/libxfs.h
@@ -169,6 +169,7 @@  enum ce { CE_DEBUG, CE_CONT, CE_NOTE, CE_WARN, CE_ALERT, CE_PANIC };
 #include "xfs_ialloc.h"
 
 #include "xfs_attr_leaf.h"
+#include "xfs_attr.h"
 #include "xfs_attr_remote.h"
 #include "xfs_trans_space.h"
 
diff --git a/libxfs/xfs_attr.c b/libxfs/xfs_attr.c
index 59d46a4..d03b235 100644
--- a/libxfs/xfs_attr.c
+++ b/libxfs/xfs_attr.c
@@ -45,7 +45,7 @@  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_addname(struct xfs_delattr_context *dac);
 STATIC int xfs_attr_leaf_removename(struct xfs_delattr_context *dac);
 STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);
 
@@ -53,12 +53,13 @@  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_delattr_context *dac);
 STATIC int xfs_attr_node_removename(struct xfs_delattr_context *dac);
 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);
 STATIC int xfs_attr_refillstate(xfs_da_state_t *state);
+STATIC int xfs_attr_leaf_try_add(struct xfs_da_args *args, struct xfs_buf *bp);
 
 STATIC void
 xfs_delattr_context_init(
@@ -228,8 +229,11 @@  xfs_attr_is_shortform(
 
 /*
  * Attempts to set an attr in shortform, or converts the tree to leaf form if
- * there is not enough room.  If the attr is set, the transaction is committed
- * and set to NULL.
+ * there is not enough room.  This function is meant to operate as a helper
+ * routine to the delayed attribute functions.  It returns -EAGAIN to indicate
+ * that the calling function should roll the transaction, and then proceed to
+ * add the attr in leaf form.  This subroutine does not expect to be recalled
+ * again like the other delayed attr routines do.
  */
 STATIC int
 xfs_attr_set_shortform(
@@ -237,16 +241,16 @@  xfs_attr_set_shortform(
 	struct xfs_buf		**leaf_bp)
 {
 	struct xfs_inode	*dp = args->dp;
-	int			error, error2 = 0;
+	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) {
-		error2 = xfs_trans_commit(args->trans);
-		args->trans = NULL;
-		return error ? error : error2;
+		return error;
 	}
 	/*
 	 * It won't fit in the shortform, transform to a leaf block.  GROT:
@@ -259,18 +263,10 @@  xfs_attr_set_shortform(
 	/*
 	 * 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);
-	error = xfs_defer_finish(&args->trans);
-	xfs_trans_bhold_release(args->trans, *leaf_bp);
-	if (error) {
-		xfs_trans_brelse(args->trans, *leaf_bp);
-		return error;
-	}
-
-	return 0;
+	return -EAGAIN;
 }
 
 /*
@@ -280,9 +276,83 @@  int
 xfs_attr_set_args(
 	struct xfs_da_args	*args)
 {
-	struct xfs_inode	*dp = args->dp;
-	struct xfs_buf          *leaf_bp = NULL;
-	int			error = 0;
+	struct xfs_buf			*leaf_bp = NULL;
+	int				error = 0;
+	struct xfs_delattr_context	dac;
+
+	xfs_delattr_context_init(&dac, args);
+
+	do {
+		error = xfs_attr_set_iter(&dac, &leaf_bp);
+		if (error != -EAGAIN)
+			break;
+
+		if (dac.flags & XFS_DAC_DEFER_FINISH) {
+			dac.flags &= ~XFS_DAC_DEFER_FINISH;
+			error = xfs_defer_finish(&args->trans);
+			if (error)
+				break;
+		}
+
+		error = xfs_trans_roll_inode(&args->trans, args->dp);
+		if (error)
+			break;
+
+		if (leaf_bp) {
+			xfs_trans_bjoin(args->trans, leaf_bp);
+			xfs_trans_bhold(args->trans, leaf_bp);
+		}
+
+	} while (true);
+
+	return error;
+}
+
+/*
+ * 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.
+ */
+int
+xfs_attr_set_iter(
+	struct xfs_delattr_context	*dac,
+	struct xfs_buf			**leaf_bp)
+{
+	struct xfs_da_args		*args = dac->da_args;
+	struct xfs_inode		*dp = args->dp;
+	int				error = 0;
+	int				sf_size;
+
+	/* State machine switch */
+	switch (dac->dela_state) {
+	case XFS_DAS_ADD_LEAF:
+		goto das_add_leaf;
+	case XFS_DAS_ALLOC_LEAF:
+	case XFS_DAS_FLIP_LFLAG:
+	case XFS_DAS_FOUND_LBLK:
+		goto das_leaf;
+	case XFS_DAS_FOUND_NBLK:
+	case XFS_DAS_FLIP_NFLAG:
+	case XFS_DAS_ALLOC_NODE:
+	case XFS_DAS_LEAF_TO_NODE:
+		goto das_node;
+	default:
+		break;
+	}
+
+	/*
+	 * New inodes may not have an attribute fork yet. So set the attribute
+	 * fork appropriately
+	 */
+	if (XFS_IFORK_Q((args->dp)) == 0) {
+		sf_size = sizeof(struct xfs_attr_sf_hdr) +
+		     XFS_ATTR_SF_ENTSIZE_BYNAME(args->namelen, args->valuelen);
+		xfs_bmap_set_attrforkoff(args->dp, sf_size, NULL);
+		args->dp->i_afp = kmem_zone_zalloc(xfs_ifork_zone, 0);
+		args->dp->i_afp->if_flags = XFS_IFEXTENTS;
+	}
 
 	/*
 	 * If the attribute list is already in leaf format, jump straight to
@@ -293,40 +363,53 @@  xfs_attr_set_args(
 	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.
+		 * If the attr was successfully set in shortform, no need to
+		 * continue.  Otherwise, is it converted from shortform to leaf
+		 * and -EAGAIN is returned.
 		 */
-		error = xfs_attr_set_shortform(args, &leaf_bp);
-		if (error || !args->trans)
-			return error;
+		error = xfs_attr_set_shortform(args, leaf_bp);
+		if (error == -EAGAIN) {
+			dac->flags |= XFS_DAC_DEFER_FINISH;
+			dac->dela_state = XFS_DAS_ADD_LEAF;
+		}
+		return error;
 	}
 
-	if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
-		error = xfs_attr_leaf_addname(args);
-		if (error != -ENOSPC)
-			return error;
+das_add_leaf:
 
-		/*
-		 * Commit that transaction so that the node_addname()
-		 * call can manage its own transactions.
-		 */
-		error = xfs_defer_finish(&args->trans);
-		if (error)
-			return error;
+	/*
+	 * After a shortform to leaf conversion, we need to hold the leaf and
+	 * cylce out the transaction.  When we get back, we need to release
+	 * the leaf.
+	 */
+	if (*leaf_bp != NULL) {
+		xfs_trans_brelse(args->trans, *leaf_bp);
+		*leaf_bp = NULL;
+	}
 
-		/*
-		 * Commit the current trans (including the inode) and
-		 * start a new one.
-		 */
-		error = xfs_trans_roll_inode(&args->trans, dp);
-		if (error)
+	if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
+		error = xfs_attr_leaf_try_add(args, *leaf_bp);
+		switch (error) {
+		case -ENOSPC:
+			dac->flags |= XFS_DAC_DEFER_FINISH;
+			dac->dela_state = XFS_DAS_LEAF_TO_NODE;
+			return -EAGAIN;
+		case 0:
+			dac->dela_state = XFS_DAS_FOUND_LBLK;
+			return -EAGAIN;
+		default:
 			return error;
-
+		}
+das_leaf:
+		error = xfs_attr_leaf_addname(dac);
+		if (error == -ENOSPC) {
+			dac->dela_state = XFS_DAS_LEAF_TO_NODE;
+			return -EAGAIN;
+		}
+		return error;
 	}
-
-	error = xfs_attr_node_addname(args);
+das_node:
+	error = xfs_attr_node_addname(dac);
 	return error;
 }
 
@@ -717,28 +800,32 @@  out_brelse:
  *
  * 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).
+ *
+ * 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_leaf_addname(
-	struct xfs_da_args	*args)
+	struct xfs_delattr_context	*dac)
 {
-	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;
+	struct xfs_da_args		*args = dac->da_args;
+	struct xfs_buf			*bp = NULL;
+	int				error, forkoff;
+	struct xfs_inode		*dp = args->dp;
 
-	/*
-	 * 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;
+	/* State machine switch */
+	switch (dac->dela_state) {
+	case XFS_DAS_FLIP_LFLAG:
+		goto das_flip_flag;
+	case XFS_DAS_ALLOC_LEAF:
+		goto das_alloc_leaf;
+	case XFS_DAS_RM_LBLK:
+		goto das_rm_lblk;
+	default:
+		break;
+	}
 
 	/*
 	 * If there was an out-of-line value, allocate the blocks we
@@ -747,7 +834,28 @@  xfs_attr_leaf_addname(
 	 * maximum size of a transaction and/or hit a deadlock.
 	 */
 	if (args->rmtblkno > 0) {
-		error = xfs_attr_rmtval_set(args);
+
+		/* Open coded xfs_attr_rmtval_set without trans handling */
+		error = xfs_attr_rmtval_set_init(dac);
+		if (error)
+			return error;
+
+		/*
+		 * Roll through the "value", allocating blocks on disk as
+		 * required.
+		 */
+das_alloc_leaf:
+		while (dac->blkcnt > 0) {
+			error = xfs_attr_rmtval_set_blk(dac);
+			if (error)
+				return error;
+
+			dac->flags |= XFS_DAC_DEFER_FINISH;
+			dac->dela_state = XFS_DAS_ALLOC_LEAF;
+			return -EAGAIN;
+		}
+
+		error = xfs_attr_rmtval_set_value(args);
 		if (error)
 			return error;
 	}
@@ -766,22 +874,25 @@  xfs_attr_leaf_addname(
 		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;
-
+		dac->dela_state = XFS_DAS_FLIP_LFLAG;
+		return -EAGAIN;
+das_flip_flag:
 		/*
 		 * Dismantle the "old" attribute/value pair by removing
 		 * a "remote" value (if it exists).
 		 */
 		xfs_attr_restore_rmt_blk(args);
 
+		xfs_attr_rmtval_invalidate(args);
+das_rm_lblk:
 		if (args->rmtblkno) {
-			error = xfs_attr_rmtval_remove(args);
+			error = __xfs_attr_rmtval_remove(args);
+
+			if (error == -EAGAIN) {
+				dac->dela_state = XFS_DAS_RM_LBLK;
+				return -EAGAIN;
+			}
+
 			if (error)
 				return error;
 		}
@@ -800,15 +911,11 @@  xfs_attr_leaf_addname(
 		/*
 		 * If the result is small enough, shrink it all into the inode.
 		 */
-		if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
+		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 */
-			if (error)
-				return error;
-			error = xfs_defer_finish(&args->trans);
-			if (error)
-				return error;
-		}
+
+		dac->flags |= XFS_DAC_DEFER_FINISH;
 
 	} else if (args->rmtblkno > 0) {
 		/*
@@ -968,16 +1075,23 @@  xfs_attr_node_hasname(
  *
  * "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_addname(
-	struct xfs_da_args	*args)
+	struct xfs_delattr_context	*dac)
 {
-	struct xfs_da_state	*state;
-	struct xfs_da_state_blk	*blk;
-	struct xfs_inode	*dp;
-	struct xfs_mount	*mp;
-	int			retval, error;
+	struct xfs_da_args		*args = dac->da_args;
+	struct xfs_da_state		*state = NULL;
+	struct xfs_da_state_blk		*blk;
+	struct xfs_inode		*dp;
+	struct xfs_mount		*mp;
+	int				retval = 0;
+	int				error = 0;
 
 	trace_xfs_attr_node_addname(args);
 
@@ -986,7 +1100,21 @@  xfs_attr_node_addname(
 	 */
 	dp = args->dp;
 	mp = dp->i_mount;
-restart:
+
+	/* State machine switch */
+	switch (dac->dela_state) {
+	case XFS_DAS_FLIP_NFLAG:
+		goto das_flip_flag;
+	case XFS_DAS_FOUND_NBLK:
+		goto das_found_nblk;
+	case XFS_DAS_ALLOC_NODE:
+		goto das_alloc_node;
+	case XFS_DAS_RM_NBLK:
+		goto das_rm_nblk;
+	default:
+		break;
+	}
+
 	/*
 	 * Search to see if name already exists, and get back a pointer
 	 * to where it should go.
@@ -1032,19 +1160,13 @@  restart:
 			error = xfs_attr3_leaf_to_node(args);
 			if (error)
 				goto out;
-			error = xfs_defer_finish(&args->trans);
-			if (error)
-				goto out;
 
 			/*
-			 * Commit the node conversion and start the next
-			 * trans in the chain.
+			 * Restart routine from the top.  No need to set  the
+			 * state
 			 */
-			error = xfs_trans_roll_inode(&args->trans, dp);
-			if (error)
-				goto out;
-
-			goto restart;
+			dac->flags |= XFS_DAC_DEFER_FINISH;
+			return -EAGAIN;
 		}
 
 		/*
@@ -1056,9 +1178,7 @@  restart:
 		error = xfs_da3_split(state);
 		if (error)
 			goto out;
-		error = xfs_defer_finish(&args->trans);
-		if (error)
-			goto out;
+		dac->flags |= XFS_DAC_DEFER_FINISH;
 	} else {
 		/*
 		 * Addition succeeded, update Btree hashvals.
@@ -1073,13 +1193,9 @@  restart:
 	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;
+	dac->dela_state = XFS_DAS_FOUND_NBLK;
+	return -EAGAIN;
+das_found_nblk:
 
 	/*
 	 * If there was an out-of-line value, allocate the blocks we
@@ -1088,7 +1204,27 @@  restart:
 	 * maximum size of a transaction and/or hit a deadlock.
 	 */
 	if (args->rmtblkno > 0) {
-		error = xfs_attr_rmtval_set(args);
+		/* Open coded xfs_attr_rmtval_set without trans handling */
+		error = xfs_attr_rmtval_set_init(dac);
+		if (error)
+			return error;
+
+		/*
+		 * Roll through the "value", allocating blocks on disk as
+		 * required.
+		 */
+das_alloc_node:
+		while (dac->blkcnt > 0) {
+			error = xfs_attr_rmtval_set_blk(dac);
+			if (error)
+				return error;
+
+			dac->flags |= XFS_DAC_DEFER_FINISH;
+			dac->dela_state = XFS_DAS_ALLOC_NODE;
+			return -EAGAIN;
+		}
+
+		error = xfs_attr_rmtval_set_value(args);
 		if (error)
 			return error;
 	}
@@ -1111,18 +1247,26 @@  restart:
 		 * 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;
-
+		dac->dela_state = XFS_DAS_FLIP_NFLAG;
+		return -EAGAIN;
+das_flip_flag:
 		/*
 		 * Dismantle the "old" attribute/value pair by removing
 		 * a "remote" value (if it exists).
 		 */
 		xfs_attr_restore_rmt_blk(args);
 
+		xfs_attr_rmtval_invalidate(args);
+
+das_rm_nblk:
 		if (args->rmtblkno) {
-			error = xfs_attr_rmtval_remove(args);
+			error = __xfs_attr_rmtval_remove(args);
+
+			if (error == -EAGAIN) {
+				dac->dela_state = XFS_DAS_RM_NBLK;
+				return -EAGAIN;
+			}
+
 			if (error)
 				return error;
 		}
@@ -1140,7 +1284,6 @@  restart:
 		error = xfs_da3_node_lookup_int(state, &retval);
 		if (error)
 			goto out;
-
 		/*
 		 * Remove the name and update the hashvals in the tree.
 		 */
@@ -1148,7 +1291,6 @@  restart:
 		ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
 		error = xfs_attr3_leaf_remove(blk->bp, args);
 		xfs_da3_fixhashpath(state, &state->path);
-
 		/*
 		 * Check to see if the tree needs to be collapsed.
 		 */
@@ -1156,11 +1298,9 @@  restart:
 			error = xfs_da3_join(state);
 			if (error)
 				goto out;
-			error = xfs_defer_finish(&args->trans);
-			if (error)
-				goto out;
-		}
 
+			dac->flags |= XFS_DAC_DEFER_FINISH;
+		}
 	} else if (args->rmtblkno > 0) {
 		/*
 		 * Added a "remote" value, just clear the incomplete flag.
diff --git a/libxfs/xfs_attr.h b/libxfs/xfs_attr.h
index 0e8ae1a..67af9d1 100644
--- a/libxfs/xfs_attr.h
+++ b/libxfs/xfs_attr.h
@@ -93,6 +93,16 @@  enum xfs_delattr_state {
 				      /* Zero is uninitalized */
 	XFS_DAS_RM_SHRINK	= 1,  /* We are shrinking the tree */
 	XFS_DAS_RMTVAL_REMOVE,	      /* We are removing remote value blocks */
+	XFS_DAS_ADD_LEAF,	      /* We are adding a leaf attr */
+	XFS_DAS_FOUND_LBLK,	      /* We found leaf blk for attr */
+	XFS_DAS_LEAF_TO_NODE,	      /* Converted leaf to node */
+	XFS_DAS_FOUND_NBLK,	      /* We found node blk for attr */
+	XFS_DAS_ALLOC_LEAF,	      /* We are allocating leaf blocks */
+	XFS_DAS_FLIP_LFLAG,	      /* Flipped leaf INCOMPLETE attr flag */
+	XFS_DAS_RM_LBLK,	      /* A rename is removing leaf blocks */
+	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 */
 };
 
 /*
@@ -105,8 +115,13 @@  enum xfs_delattr_state {
  */
 struct xfs_delattr_context {
 	struct xfs_da_args      *da_args;
+	struct xfs_bmbt_irec	map;
+	struct xfs_buf		*leaf_bp;
+	xfs_fileoff_t		lfileoff;
 	struct xfs_da_state     *da_state;
 	struct xfs_da_state_blk *blk;
+	xfs_dablk_t		lblkno;
+	int			blkcnt;
 	unsigned int            flags;
 	enum xfs_delattr_state  dela_state;
 };
@@ -126,6 +141,7 @@  int xfs_attr_get_ilocked(struct xfs_da_args *args);
 int xfs_attr_get(struct xfs_da_args *args);
 int xfs_attr_set(struct xfs_da_args *args);
 int xfs_attr_set_args(struct xfs_da_args *args);
+int xfs_attr_set_iter(struct xfs_delattr_context *dac, struct xfs_buf **leaf_bp);
 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);
diff --git a/libxfs/xfs_attr_leaf.c b/libxfs/xfs_attr_leaf.c
index e3f8457..5971e3e 100644
--- a/libxfs/xfs_attr_leaf.c
+++ b/libxfs/xfs_attr_leaf.c
@@ -19,6 +19,7 @@ 
 #include "xfs_bmap_btree.h"
 #include "xfs_bmap.h"
 #include "xfs_attr_sf.h"
+#include "xfs_attr.h"
 #include "xfs_attr_remote.h"
 #include "xfs_attr.h"
 #include "xfs_attr_leaf.h"
diff --git a/libxfs/xfs_attr_remote.c b/libxfs/xfs_attr_remote.c
index a9cd28d..f5ae92b 100644
--- a/libxfs/xfs_attr_remote.c
+++ b/libxfs/xfs_attr_remote.c
@@ -442,7 +442,7 @@  xfs_attr_rmtval_get(
  * Find a "hole" in the attribute address space large enough for us to drop the
  * new attribute's value into
  */
-STATIC int
+int
 xfs_attr_rmt_find_hole(
 	struct xfs_da_args	*args)
 {
@@ -469,7 +469,7 @@  xfs_attr_rmt_find_hole(
 	return 0;
 }
 
-STATIC int
+int
 xfs_attr_rmtval_set_value(
 	struct xfs_da_args	*args)
 {
@@ -629,6 +629,71 @@  xfs_attr_rmtval_set(
 }
 
 /*
+ * Find a hole for the attr and store it in the delayed attr context.  This
+ * initializes the context to roll through allocating an attr extent for a
+ * delayed attr operation
+ */
+int
+xfs_attr_rmtval_set_init(
+	struct xfs_delattr_context	*dac)
+{
+	struct xfs_da_args		*args = dac->da_args;
+	struct xfs_bmbt_irec		*map = &dac->map;
+	int error;
+
+	dac->lblkno = 0;
+	dac->lfileoff = 0;
+	dac->blkcnt = 0;
+	args->rmtblkcnt = 0;
+	args->rmtblkno = 0;
+	memset(map, 0, sizeof(struct xfs_bmbt_irec));
+
+	error = xfs_attr_rmt_find_hole(args);
+	if (error)
+		return error;
+
+	dac->blkcnt = args->rmtblkcnt;
+	dac->lblkno = args->rmtblkno;
+
+	return error;
+}
+
+/*
+ * Write one block of the value associated with an attribute into the
+ * out-of-line buffer that we have defined for it. This is similar to a subset
+ * of xfs_attr_rmtval_set, but records the current block to the delayed attr
+ * context, and leaves transaction handling to the caller.
+ */
+int
+xfs_attr_rmtval_set_blk(
+	struct xfs_delattr_context	*dac)
+{
+	struct xfs_da_args		*args = dac->da_args;
+	struct xfs_inode		*dp = args->dp;
+	struct xfs_bmbt_irec		*map = &dac->map;
+	int nmap;
+	int error;
+
+	nmap = 1;
+	error = xfs_bmapi_write(args->trans, dp,
+		  (xfs_fileoff_t)dac->lblkno,
+		  dac->blkcnt, XFS_BMAPI_ATTRFORK,
+		  args->total, map, &nmap);
+	if (error)
+		return error;
+
+	ASSERT(nmap == 1);
+	ASSERT((map->br_startblock != DELAYSTARTBLOCK) &&
+	       (map->br_startblock != HOLESTARTBLOCK));
+
+	/* roll attribute extent map forwards */
+	dac->lblkno += map->br_blockcount;
+	dac->blkcnt -= map->br_blockcount;
+
+	return 0;
+}
+
+/*
  * Remove the value associated with an attribute by deleting the
  * out-of-line buffer that it is stored on.
  */
@@ -670,48 +735,6 @@  xfs_attr_rmtval_invalidate(
 }
 
 /*
- * Remove the value associated with an attribute by deleting the
- * out-of-line buffer that it is stored on.
- */
-int
-xfs_attr_rmtval_remove(
-	struct xfs_da_args      *args)
-{
-	xfs_dablk_t		lblkno;
-	int			blkcnt;
-	int			error = 0;
-	int			done = 0;
-
-	trace_xfs_attr_rmtval_remove(args);
-
-	error = xfs_attr_rmtval_invalidate(args);
-	if (error)
-		return error;
-	/*
-	 * Keep de-allocating extents until the remote-value region is gone.
-	 */
-	lblkno = args->rmtblkno;
-	blkcnt = args->rmtblkcnt;
-	while (!done) {
-		error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
-				    XFS_BMAPI_ATTRFORK, 1, &done);
-		if (error)
-			return error;
-		error = xfs_defer_finish(&args->trans);
-		if (error)
-			return error;
-
-		/*
-		 * Close out trans and start the next one in the chain.
-		 */
-		error = xfs_trans_roll_inode(&args->trans, args->dp);
-		if (error)
-			return error;
-	}
-	return 0;
-}
-
-/*
  * 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 recall the function
diff --git a/libxfs/xfs_attr_remote.h b/libxfs/xfs_attr_remote.h
index ee3337b..482dff9 100644
--- a/libxfs/xfs_attr_remote.h
+++ b/libxfs/xfs_attr_remote.h
@@ -15,4 +15,8 @@  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_rmt_find_hole(struct xfs_da_args *args);
+int xfs_attr_rmtval_set_value(struct xfs_da_args *args);
+int xfs_attr_rmtval_set_blk(struct xfs_delattr_context *dac);
+int xfs_attr_rmtval_set_init(struct xfs_delattr_context *dac);
 #endif /* __XFS_ATTR_REMOTE_H__ */