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authorDarrick J. Wong <djwong@kernel.org>2024-08-13 10:39:39 +0300
committerChandan Babu R <chandanbabu@kernel.org>2024-09-03 07:37:38 +0300
commitf1204d96450fa7650dc27b8839df159a01998737 (patch)
treeada24ee18b026bbda30070b88d35e3c08d0d0bb6 /fs/xfs/xfs_file.c
parent816e3599ca9b9bbfdc456433cc707e75f2c31104 (diff)
downloadlinux-f1204d96450fa7650dc27b8839df159a01998737.tar.xz
xfs: only free posteof blocks on first close
Certain workloads fragment files on XFS very badly, such as a software package that creates a number of threads, each of which repeatedly run the sequence: open a file, perform a synchronous write, and close the file, which defeats the speculative preallocation mechanism. We work around this problem by only deleting posteof blocks the /first/ time a file is closed to preserve the behavior that unpacking a tarball lays out files one after the other with no gaps. Signed-off-by: Darrick J. Wong <djwong@kernel.org> [hch: rebased, updated comment, renamed the flag] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
Diffstat (limited to 'fs/xfs/xfs_file.c')
-rw-r--r--fs/xfs/xfs_file.c32
1 files changed, 11 insertions, 21 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 60424e642307..30b553ac8f56 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1204,15 +1204,21 @@ xfs_file_release(
* exposed to that problem.
*/
if (xfs_iflags_test_and_clear(ip, XFS_ITRUNCATED)) {
- xfs_iflags_clear(ip, XFS_IDIRTY_RELEASE);
+ xfs_iflags_clear(ip, XFS_EOFBLOCKS_RELEASED);
if (ip->i_delayed_blks > 0)
filemap_flush(inode->i_mapping);
}
/*
* XFS aggressively preallocates post-EOF space to generate contiguous
- * allocations for writers that append to the end of the file and we
- * try to free these when an open file context is released.
+ * allocations for writers that append to the end of the file.
+ *
+ * To support workloads that close and reopen the file frequently, these
+ * preallocations usually persist after a close unless it is the first
+ * close for the inode. This is a tradeoff to generate tightly packed
+ * data layouts for unpacking tarballs or similar archives that write
+ * one file after another without going back to it while keeping the
+ * preallocation for files that have recurring open/write/close cycles.
*
* There is no point in freeing blocks here for open but unlinked files
* as they will be taken care of by the inactivation path soon.
@@ -1230,25 +1236,9 @@ xfs_file_release(
(file->f_mode & FMODE_WRITE) &&
xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
if (xfs_can_free_eofblocks(ip) &&
- !xfs_iflags_test(ip, XFS_IDIRTY_RELEASE)) {
- /*
- * Check if the inode is being opened, written and
- * closed frequently and we have delayed allocation
- * blocks outstanding (e.g. streaming writes from the
- * NFS server), truncating the blocks past EOF will
- * cause fragmentation to occur.
- *
- * In this case don't do the truncation, but we have to
- * be careful how we detect this case. Blocks beyond EOF
- * show up as i_delayed_blks even when the inode is
- * clean, so we need to truncate them away first before
- * checking for a dirty release. Hence on the first
- * dirty close we will still remove the speculative
- * allocation, but after that we will leave it in place.
- */
+ !xfs_iflags_test(ip, XFS_EOFBLOCKS_RELEASED)) {
xfs_free_eofblocks(ip);
- if (ip->i_delayed_blks)
- xfs_iflags_set(ip, XFS_IDIRTY_RELEASE);
+ xfs_iflags_set(ip, XFS_EOFBLOCKS_RELEASED);
}
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
}