xfs: split xfs_bmap_add_attrfork into two pieces

Split this function into two pieces -- one to make the actual changes to
the inode core to add the attr fork, and another one to deal with
getting the transaction and locking the inodes.

The next couple of patches will need this to be split into two.  One
patch implements committing new parent pointer recordsets to damaged
files.  If one file has an attr fork and the other does not, we have to
create the missing attr fork before the atomic swap transaction, and can
use the behavior encoded in the current xfs_bmap_add_attrfork.

The second patch adapts /lost+found adoptions to handle parent pointers
correctly.  The adoption process will add a parent pointer to a child
that is being moved to /lost+found, but this requires that the attr fork
already exists.  We don't know if we're actually going to commit the
adoption until we've already reserved a transaction and taken the
ILOCKs, which means that we must have a way to bypass the start of the
current xfs_bmap_add_attrfork.

Therefore, create xfs_attr_add_fork as the helper that creates a
transaction and takes locks; and make xfs_bmap_add_attrfork the function
that updates the inode core and allocates the incore attr fork.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 10 insertions, 26 deletions

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 1f528cf2d906..6053f5e5c71e 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -1025,38 +1025,29 @@ xfs_bmap_set_attrforkoff(
 }
 
 /*
- * Convert inode from non-attributed to attributed.
- * Must not be in a transaction, ip must not be locked.
+ * Convert inode from non-attributed to attributed.  Caller must hold the
+ * ILOCK_EXCL and the file cannot have an attr fork.
  */
 int						/* error code */
 xfs_bmap_add_attrfork(
-	xfs_inode_t		*ip,		/* incore inode pointer */
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip,		/* incore inode pointer */
 	int			size,		/* space new attribute needs */
 	int			rsvd)		/* xact may use reserved blks */
 {
-	xfs_mount_t		*mp;		/* mount structure */
-	xfs_trans_t		*tp;		/* transaction pointer */
-	int			blks;		/* space reservation */
+	struct xfs_mount	*mp = tp->t_mountp;
 	int			version = 1;	/* superblock attr version */
 	int			logflags;	/* logging flags */
 	int			error;		/* error return value */
 
-	mp = ip->i_mount;
+	xfs_assert_ilocked(ip, XFS_ILOCK_EXCL);
 	ASSERT(!XFS_NOT_DQATTACHED(mp, ip));
-
-	blks = XFS_ADDAFORK_SPACE_RES(mp);
-
-	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_addafork, blks, 0,
-			rsvd, &tp);
-	if (error)
-		return error;
-	if (xfs_inode_has_attr_fork(ip))
-		goto trans_cancel;
+	ASSERT(!xfs_inode_has_attr_fork(ip));
 
 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 	error = xfs_bmap_set_attrforkoff(ip, size, &version);
 	if (error)
-		goto trans_cancel;
+		return error;
 
 	xfs_ifork_init_attr(ip, XFS_DINODE_FMT_EXTENTS, 0);
 	logflags = 0;
@@ -1077,7 +1068,7 @@ xfs_bmap_add_attrfork(
 	if (logflags)
 		xfs_trans_log_inode(tp, ip, logflags);
 	if (error)
-		goto trans_cancel;
+		return error;
 	if (!xfs_has_attr(mp) ||
 	   (!xfs_has_attr2(mp) && version == 2)) {
 		bool log_sb = false;
@@ -1096,14 +1087,7 @@ xfs_bmap_add_attrfork(
 			xfs_log_sb(tp);
 	}
 
-	error = xfs_trans_commit(tp);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
-	return error;
-
-trans_cancel:
-	xfs_trans_cancel(tp);
-	xfs_iunlock(ip, XFS_ILOCK_EXCL);
-	return error;
+	return 0;
 }
 
 /*