xfs: skip unallocated regions of inode chunks in xfs_ifree_cluster()

xfs_ifree_cluster() is called to mark all in-memory inodes and inode
buffers as stale. This occurs after we've removed the inobt records and
dropped any references of inobt data. xfs_ifree_cluster() uses the
starting inode number to walk the namespace of inodes expected for a
single chunk a cluster buffer at a time. The cluster buffer disk
addresses are calculated by decoding the sequential inode numbers
expected from the chunk.

The problem with this approach is that if the inode chunk being removed
is a sparse chunk, not all of the buffer addresses that are calculated
as part of this sequence may be inode clusters. Attempting to acquire
the buffer based on expected inode characterstics (i.e., cluster length)
can lead to errors and is generally incorrect.

We already use a couple variables to carry requisite state from
xfs_difree() to xfs_ifree_cluster(). Rather than add a third, define a
new internal structure to carry the existing parameters through these
functions. Add an alloc field that represents the physical allocation
bitmap of inodes in the chunk being removed. Modify xfs_ifree_cluster()
to check each inode against the bitmap and skip the clusters that were
never allocated as real inodes on disk.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 7 insertions, 10 deletions

diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 47be76e7a124..c6d684ed84d0 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -1885,8 +1885,7 @@ xfs_difree_inobt(
 	struct xfs_buf			*agbp,
 	xfs_agino_t			agino,
 	struct xfs_bmap_free		*flist,
-	int				*deleted,
-	xfs_ino_t			*first_ino,
+	struct xfs_icluster		*xic,
 	struct xfs_inobt_rec_incore	*orec)
 {
 	struct xfs_agi			*agi = XFS_BUF_TO_AGI(agbp);
@@ -1947,9 +1946,9 @@ xfs_difree_inobt(
 	if (!(mp->m_flags & XFS_MOUNT_IKEEP) &&
 	    rec.ir_free == XFS_INOBT_ALL_FREE &&
 	    mp->m_sb.sb_inopblock <= XFS_INODES_PER_CHUNK) {
-
-		*deleted = 1;
-		*first_ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino);
+		xic->deleted = 1;
+		xic->first_ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino);
+		xic->alloc = xfs_inobt_irec_to_allocmask(&rec);
 
 		/*
 		 * Remove the inode cluster from the AGI B+Tree, adjust the
@@ -1974,7 +1973,7 @@ xfs_difree_inobt(
 
 		xfs_difree_inode_chunk(mp, agno, &rec, flist);
 	} else {
-		*deleted = 0;
+		xic->deleted = 0;
 
 		error = xfs_inobt_update(cur, &rec);
 		if (error) {
@@ -2118,8 +2117,7 @@ xfs_difree(
 	struct xfs_trans	*tp,		/* transaction pointer */
 	xfs_ino_t		inode,		/* inode to be freed */
 	struct xfs_bmap_free	*flist,		/* extents to free */
-	int			*deleted,/* set if inode cluster was deleted */
-	xfs_ino_t		*first_ino)/* first inode in deleted cluster */
+	struct xfs_icluster	*xic)	/* cluster info if deleted */
 {
 	/* REFERENCED */
 	xfs_agblock_t		agbno;	/* block number containing inode */
@@ -2170,8 +2168,7 @@ xfs_difree(
 	/*
 	 * Fix up the inode allocation btree.
 	 */
-	error = xfs_difree_inobt(mp, tp, agbp, agino, flist, deleted, first_ino,
-				 &rec);
+	error = xfs_difree_inobt(mp, tp, agbp, agino, flist, xic, &rec);
 	if (error)
 		goto error0;