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authorLachlan McIlroy <lmcilroy@redhat.com>2009-04-23 22:18:00 -0400
committerFelix Blyakher <felixb@sgi.com>2009-04-30 00:25:25 -0500
commitdef6b3ba56b637d58126ef67fc19bab57945fcc4 (patch)
tree983618561a50a6f9a423577c7fcd46fc1c539a62 /fs/xfs
parentdc2a5536d633dd2318f82f3d5ad3c9e43cfc21d7 (diff)
xfs_file_last_byte() needs to acquire ilock
We had some systems crash with this stack: [<a00000010000cb20>] ia64_leave_kernel+0x0/0x280 [<a00000021291ca00>] xfs_bmbt_get_startoff+0x0/0x20 [xfs] [<a0000002129080b0>] xfs_bmap_last_offset+0x210/0x280 [xfs] [<a00000021295b010>] xfs_file_last_byte+0x70/0x1a0 [xfs] [<a00000021295b200>] xfs_itruncate_start+0xc0/0x1a0 [xfs] [<a0000002129935f0>] xfs_inactive_free_eofblocks+0x290/0x460 [xfs] [<a000000212998fb0>] xfs_release+0x1b0/0x240 [xfs] [<a0000002129ad930>] xfs_file_release+0x70/0xa0 [xfs] [<a000000100162ea0>] __fput+0x1a0/0x420 [<a000000100163160>] fput+0x40/0x60 The problem here is that xfs_file_last_byte() does not acquire the inode lock and can therefore race with another thread that is modifying the extext list. While xfs_bmap_last_offset() is trying to lookup what was the last extent some extents were merged and the extent list shrunk so the index we lookup is now beyond the end of the extent list and potentially in a freed buffer. Signed-off-by: Lachlan McIlroy <lmcilroy@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Felix Blyakher <felixb@sgi.com> Signed-off-by: Felix Blyakher <felixb@sgi.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_inode.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index e7ae08d1df48..123b20c8cbf2 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1258,8 +1258,10 @@ xfs_file_last_byte(
* necessary.
*/
if (ip->i_df.if_flags & XFS_IFEXTENTS) {
+ xfs_ilock(ip, XFS_ILOCK_SHARED);
error = xfs_bmap_last_offset(NULL, ip, &last_block,
XFS_DATA_FORK);
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (error) {
last_block = 0;
}