[PATCH v2 02/11] xfs: Switch atomic write size check in xfs_file_write_iter()

John Garry
2025-02-13T13:57:17Z

Currently the size of atomic write allowed is fixed at the blocksize.

To start to lift this restriction, refactor xfs_get_atomic_write_attr()
to into a helper - xfs_report_atomic_write() - and use that helper to
find the per-inode atomic write limits and check according to that.

Signed-off-by: John Garry <john.g.garry@oracle.com>
---
fs/xfs/xfs_file.c | 12 +++++-------
fs/xfs/xfs_iops.c | 20 +++++++++++++++++---
fs/xfs/xfs_iops.h | 3 +++
3 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index f7a7d89c345e..258c82cbce12 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -853,14 +853,12 @@ xfs_file_write_iter(
return xfs_file_dax_write(iocb, from);

if (iocb->ki_flags & IOCB_ATOMIC) {
- /*
- * Currently only atomic writing of a single FS block is
- * supported. It would be possible to atomic write smaller than
- * a FS block, but there is no requirement to support this.
- * Note that iomap also does not support this yet.
- */
- if (ocount != ip->i_mount->m_sb.sb_blocksize)
+ unsigned int unit_min, unit_max;
+
+ xfs_get_atomic_write_attr(ip, &unit_min, &unit_max);
+ if (ocount < unit_min || ocount > unit_max)
return -EINVAL;
+
ret = generic_atomic_write_valid(iocb, from);
if (ret)
return ret;
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 40289fe6f5b2..ea79fb246e33 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -600,15 +600,29 @@ xfs_report_dioalign(
stat->dio_offset_align = stat->dio_read_offset_align;
}

+void
+xfs_get_atomic_write_attr(
+ struct xfs_inode *ip,
+ unsigned int *unit_min,
+ unsigned int *unit_max)
+{
+ if (!xfs_inode_can_atomicwrite(ip)) {
+ *unit_min = *unit_max = 0;
+ return;
+ }
+
+ *unit_min = *unit_max = ip->i_mount->m_sb.sb_blocksize;
+}
+
static void
xfs_report_atomic_write(
struct xfs_inode *ip,
struct kstat *stat)
{
- unsigned int unit_min = 0, unit_max = 0;
+ unsigned int unit_min, unit_max;
+
+ xfs_get_atomic_write_attr(ip, &unit_min, &unit_max);

- if (xfs_inode_can_atomicwrite(ip))
- unit_min = unit_max = ip->i_mount->m_sb.sb_blocksize;
generic_fill_statx_atomic_writes(stat, unit_min, unit_max);
}

diff --git a/fs/xfs/xfs_iops.h b/fs/xfs/xfs_iops.h
index 3c1a2605ffd2..ce7bdeb9a79c 100644
--- a/fs/xfs/xfs_iops.h
+++ b/fs/xfs/xfs_iops.h
@@ -19,5 +19,8 @@ int xfs_inode_init_security(struct inode *inode, struct inode *dir,
extern void xfs_setup_inode(struct xfs_inode *ip);
extern void xfs_setup_iops(struct xfs_inode *ip);
extern void xfs_diflags_to_iflags(struct xfs_inode *ip, bool init);
+void xfs_get_atomic_write_attr(struct xfs_inode *ip,
+ unsigned int *unit_min, unsigned int *unit_max);
+

#endif /* __XFS_IOPS_H__ */
--
2.31.1