[SRU][X][PATCH] xfs: fix xfs_log_ticket leak in xfs_end_io() after fs shutdown

[Rafael David Tinoco]

From: Brian Foster <bfoster at redhat.com>

BugLink: https://bugs.launchpad.net/bugs/1706132

If the filesystem has shut down, xfs_end_io() currently sets an
error on the ioend and proceeds to ioend destruction. The ioend
might contain a truncate transaction if the I/O extended the size of
the file. This transaction is only cleaned up in
xfs_setfilesize_ioend(), however, which is skipped in this case.
This results in an xfs_log_ticket leak message when the associate
cache slab is destroyed (e.g., on rmmod).

This was originally reproduced by xfs/141 on a distro kernel. The
problem is reproducible on an upstream kernel, but not easily
detected in current upstream if the xfs_log_ticket cache happens to
be merged with another cache. This can be reproduced more
deterministically with the 'slab_nomerge' kernel boot option.

Update xfs_end_io() to proceed with normal end I/O processing after
an error is set on an ioend due to fs shutdown. The I/O type-based
processing is already designed to handle an I/O error and ensure
that the ioend is cleaned up correctly.

Signed-off-by: Brian Foster <bfoster at redhat.com>
Reviewed-by: Dave Chinner <dchinner at redhat.com>
Signed-off-by: Dave Chinner <david at fromorbit.com>
Signed-off-by: Rafael David Tinoco <rafael.tinoco at canonical.com>
---
 fs/xfs/xfs_aops.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 29e7e5dd5178..159b2ee471d8 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -214,10 +214,12 @@ xfs_end_io(
 	struct xfs_inode *ip = XFS_I(ioend->io_inode);
 	int		error = 0;
 
-	if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+	/*
+	 * Set an error if the mount has shut down and proceed with end I/O
+	 * processing so it can perform whatever cleanups are necessary.
+	 */
+	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
 		ioend->io_error = -EIO;
-		goto done;
-	}
 
 	/*
 	 * For unwritten extents we need to issue transactions to convert a
-- 
2.13.3