From abeb452e0a54aa6b44ae7d20a774334bb0eae16c Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Thu, 14 Jul 2022 11:16:20 -0700 Subject: xfs: Don't free EOF blocks on close when extent size hints are set When we have a workload that does open/write/close on files with extent size hints set in parallel with other allocation, the file becomes rapidly fragmented. This is due to close() calling xfs_release() and removing the preallocated extent beyond EOF. This occurs for both buffered and direct writes that append to files with extent size hints. The existing open/write/close hueristic in xfs_release() does not catch this as writes to files using extent size hints do not use delayed allocation and hence do not leave delayed allocation blocks allocated on the inode that can be detected in xfs_release(). Hence XFS_IDIRTY_RELEASE never gets set. In xfs_file_release(), we can tell whether the inode has extent size hints set and skip EOF block truncation. We add this check to xfs_can_free_eofblocks() so that we treat the post-EOF preallocated extent like intentional preallocation and so are persistent unless directly removed by userspace. Before: Test 2: Extent size hint fragmentation counts /mnt/scratch/file.0: 1002 /mnt/scratch/file.1: 1002 /mnt/scratch/file.2: 1002 /mnt/scratch/file.3: 1002 /mnt/scratch/file.4: 1002 /mnt/scratch/file.5: 1002 /mnt/scratch/file.6: 1002 /mnt/scratch/file.7: 1002 After: Test 2: Extent size hint fragmentation counts /mnt/scratch/file.0: 4 /mnt/scratch/file.1: 4 /mnt/scratch/file.2: 4 /mnt/scratch/file.3: 4 /mnt/scratch/file.4: 4 /mnt/scratch/file.5: 4 /mnt/scratch/file.6: 4 /mnt/scratch/file.7: 4 Signed-off-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_bmap_util.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index e4126cae78b2..8319fd960638 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -708,12 +708,15 @@ xfs_can_free_eofblocks( return false; /* - * Do not free real preallocated or append-only files unless the file - * has delalloc blocks and we are forced to remove them. + * Do not free extent size hints, real preallocated or append-only files + * unless the file has delalloc blocks and we are forced to remove + * them. */ - if (ip->i_diflags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)) + if (xfs_get_extsz_hint(ip) || + (ip->i_diflags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND))) { if (!force || ip->i_delayed_blks == 0) return false; + } /* * Do not try to free post-EOF blocks if EOF is beyond the end of the -- cgit v1.2.3