[PATCH v9 08/15] xfs: refine atomic write size check in xfs_file_write_iter()
From: John Garry <john.g.garry@oracle.com>
Date: 2025-04-25 16:46:43
Also in:
linux-block, linux-ext4, linux-fsdevel, linux-xfs, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
Currently the size of atomic write allowed is fixed at the blocksize.
To start to lift this restriction, partly refactor
xfs_report_atomic_write() to into helpers -
xfs_get_atomic_write_{min, max}() - and use those helpers to find the
per-inode atomic write limits and check according to that.
Also add xfs_get_atomic_write_max_opt() to return the optimal limit, and
just return 0 since large atomics aren't supported yet.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
fs/xfs/xfs_file.c | 12 +++++-------
fs/xfs/xfs_iops.c | 36 +++++++++++++++++++++++++++++++-----
fs/xfs/xfs_iops.h | 3 +++
3 files changed, 39 insertions(+), 12 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 55bdae44e42a..e8acd6ca8f27 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c@@ -1032,14 +1032,12 @@ 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) + if (ocount < xfs_get_atomic_write_min(ip)) return -EINVAL; + + if (ocount > xfs_get_atomic_write_max(ip)) + 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 22432c300fd7..77a0606e9dc9 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c@@ -601,16 +601,42 @@ xfs_report_dioalign( stat->dio_offset_align = stat->dio_read_offset_align; } +unsigned int +xfs_get_atomic_write_min( + struct xfs_inode *ip) +{ + if (!xfs_inode_can_hw_atomic_write(ip)) + return 0; + + return ip->i_mount->m_sb.sb_blocksize; +} + +unsigned int +xfs_get_atomic_write_max( + struct xfs_inode *ip) +{ + if (!xfs_inode_can_hw_atomic_write(ip)) + return 0; + + return ip->i_mount->m_sb.sb_blocksize; +} + +unsigned int +xfs_get_atomic_write_max_opt( + struct xfs_inode *ip) +{ + return 0; +} + static void xfs_report_atomic_write( struct xfs_inode *ip, struct kstat *stat) { - unsigned int unit_min = 0, unit_max = 0; - - if (xfs_inode_can_hw_atomic_write(ip)) - unit_min = unit_max = ip->i_mount->m_sb.sb_blocksize; - generic_fill_statx_atomic_writes(stat, unit_min, unit_max, 0); + generic_fill_statx_atomic_writes(stat, + xfs_get_atomic_write_min(ip), + xfs_get_atomic_write_max(ip), + xfs_get_atomic_write_max_opt(ip)); } STATIC int
diff --git a/fs/xfs/xfs_iops.h b/fs/xfs/xfs_iops.h
index 3c1a2605ffd2..0896f6b8b3b8 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); +unsigned int xfs_get_atomic_write_min(struct xfs_inode *ip); +unsigned int xfs_get_atomic_write_max(struct xfs_inode *ip); +unsigned int xfs_get_atomic_write_max_opt(struct xfs_inode *ip); #endif /* __XFS_IOPS_H__ */
--
2.31.1