[PATCH 059/102] xfs: fix deadlock in xfs_rtfree_extent

Dave Chinner
2012-08-23T05:03:59Z

From: Kamal Dasu <kdasu.kdev@gmail.com>

Upstream commit: 5575acc7807595687288b3bbac15103f2a5462e1

To fix the deadlock caused by repeatedly calling xfs_rtfree_extent

- removed xfs_ilock() and xfs_trans_ijoin() from xfs_rtfree_extent(),
instead added asserts that the inode is locked and has an inode_item
attached to it.
- in xfs_bunmapi() when dealing with an inode with the rt flag
call xfs_ilock() and xfs_trans_ijoin() so that the
reference count is bumped on the inode and attached it to the
transaction before calling into xfs_bmap_del_extent, similar to
what we do in xfs_bmap_rtalloc.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Ben Myers <bpm@sgi.com>
---
fs/xfs/xfs_bmap.c | 9 +++++++++
fs/xfs/xfs_rtalloc.c | 9 ++++-----
2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 2af58c4..8f3b730 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -5039,6 +5039,15 @@ xfs_bunmapi(
cur->bc_private.b.flags = 0;
} else
cur = NULL;
+
+ if (isrt) {
+ /*
+ * Synchronize by locking the bitmap inode.
+ */
+ xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, mp->m_rbmip);
+ }
+
extno = 0;
while (bno != (xfs_fileoff_t)-1 && bno >= start && lastx >= 0 &&
(nexts == 0 || extno < nexts)) {
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 8f76fdf..7c62363 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -183,6 +183,7 @@ error_cancel:
oblocks = map.br_startoff + map.br_blockcount;
}
return 0;
+
error:
return error;
}
@@ -2149,11 +2150,9 @@ xfs_rtfree_extent(
xfs_buf_t *sumbp; /* summary file block buffer */

mp = tp->t_mountp;
- /*
- * Synchronize by locking the bitmap inode.
- */
- xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL);
- xfs_trans_ijoin_ref(tp, mp->m_rbmip, XFS_ILOCK_EXCL);
+
+ ASSERT(mp->m_rbmip->i_itemp != NULL);
+ ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL));

#if defined(__KERNEL__) && defined(DEBUG)
/*