[PATCH 1/5] xfs: don't treat append-only files as having preallocations

Darrick J. Wong
2024-06-12T17:46:48Z

From: Christoph Hellwig <hch@lst.de>

The XFS XFS_DIFLAG_APPEND maps to the VFS S_APPEND flag, which forbids
writes that don't append at the current EOF.

But the commit originally adding XFS_DIFLAG_APPEND support (commit
a23321e766d in xfs xfs-import repository) also checked it to skip
releasing speculative preallocations, which doesn't make any sense.

Another commit (dd9f438e3290 in the xfs-import repository) late extended
that flag to also report these speculation preallocations which should
not exist in getbmap.

Remove these checks as nothing XFS_DIFLAG_APPEND implies that
preallocations beyond EOF should exist.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_bmap_util.c | 9 ++++-----
fs/xfs/xfs_icache.c | 2 +-
2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index ac2e77ebb54c..eb8056b1c906 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -331,8 +331,7 @@ xfs_getbmap(
}

if (xfs_get_extsz_hint(ip) ||
- (ip->i_diflags &
- (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))
+ (ip->i_diflags & XFS_DIFLAG_PREALLOC))
max_len = mp->m_super->s_maxbytes;
else
max_len = XFS_ISIZE(ip);
@@ -526,10 +525,10 @@ 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 real extents in preallocated 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 (ip->i_diflags & XFS_DIFLAG_PREALLOC)
if (!force || ip->i_delayed_blks == 0)
return false;

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 0953163a2d84..41b8a5c4dd69 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -1158,7 +1158,7 @@ xfs_inode_free_eofblocks(
if (xfs_can_free_eofblocks(ip, false))
return xfs_free_eofblocks(ip);

- /* inode could be preallocated or append-only */
+ /* inode could be preallocated */
trace_xfs_inode_free_eofblocks_invalid(ip);
xfs_inode_clear_eofblocks_tag(ip);
return 0;