| From e0d76fa4475ef2cf4b52d18588b8ce95153d021b Mon Sep 17 00:00:00 2001 |
| From: Brian Foster <bfoster@redhat.com> |
| Date: Thu, 26 Jan 2017 13:18:09 -0800 |
| Subject: xfs: prevent quotacheck from overloading inode lru |
| |
| From: Brian Foster <bfoster@redhat.com> |
| |
| commit e0d76fa4475ef2cf4b52d18588b8ce95153d021b upstream. |
| |
| Quotacheck runs at mount time in situations where quota accounting must |
| be recalculated. In doing so, it uses bulkstat to visit every inode in |
| the filesystem. Historically, every inode processed during quotacheck |
| was released and immediately tagged for reclaim because quotacheck runs |
| before the superblock is marked active by the VFS. In other words, |
| the final iput() lead to an immediate ->destroy_inode() call, which |
| allowed the XFS background reclaim worker to start reclaiming inodes. |
| |
| Commit 17c12bcd3 ("xfs: when replaying bmap operations, don't let |
| unlinked inodes get reaped") marks the XFS superblock active sooner as |
| part of the mount process to support caching inodes processed during log |
| recovery. This occurs before quotacheck and thus means all inodes |
| processed by quotacheck are inserted to the LRU on release. The |
| s_umount lock is held until the mount has completed and thus prevents |
| the shrinkers from operating on the sb. This means that quotacheck can |
| excessively populate the inode LRU and lead to OOM conditions on systems |
| without sufficient RAM. |
| |
| Update the quotacheck bulkstat handler to set XFS_IGET_DONTCACHE on |
| inodes processed by quotacheck. This causes ->drop_inode() to return 1 |
| and in turn causes iput_final() to evict the inode. This preserves the |
| original quotacheck behavior and prevents it from overloading the LRU |
| and running out of memory. |
| |
| Reported-by: Martin Svec <martin.svec@zoner.cz> |
| Signed-off-by: Brian Foster <bfoster@redhat.com> |
| Reviewed-by: Eric Sandeen <sandeen@redhat.com> |
| Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> |
| Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/xfs/xfs_qm.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/fs/xfs/xfs_qm.c |
| +++ b/fs/xfs/xfs_qm.c |
| @@ -1177,7 +1177,8 @@ xfs_qm_dqusage_adjust( |
| * the case in all other instances. It's OK that we do this because |
| * quotacheck is done only at mount time. |
| */ |
| - error = xfs_iget(mp, NULL, ino, 0, XFS_ILOCK_EXCL, &ip); |
| + error = xfs_iget(mp, NULL, ino, XFS_IGET_DONTCACHE, XFS_ILOCK_EXCL, |
| + &ip); |
| if (error) { |
| *res = BULKSTAT_RV_NOTHING; |
| return error; |
