On Mon, Mar 11, 2024 at 08:22:52PM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@xxxxxxxxxx>
>
> Commit 1aa91d9c9933 ("xfs: Add async buffered write support") replace
> xfs_ilock(XFS_ILOCK_EXCL) with xfs_ilock_for_iomap() when locking the
> writing inode, and a new variable lockmode is used to indicate the lock
> mode. Although the lockmode should always be XFS_ILOCK_EXCL, it's still
> better to use this variable instead of useing XFS_ILOCK_EXCL directly
> when unlocking the inode.
>
> Fixes: 1aa91d9c9933 ("xfs: Add async buffered write support")
AFAICT, xfs_ilock_for_iomap can change lockmode from SHARED->EXCL, but
never changed away from EXCL, right? And xfs_buffered_write_iomap_begin
sets it to EXCL (and never changes it), right?
This seems like more of a code cleanup/logic bomb removal than an actual
defect that someone could actually hit, correct?
If the answers are {yes, yes, yes} then:
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
> ---
> fs/xfs/xfs_iomap.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index 18c8f168b153..ccf83e72d8ca 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -1149,13 +1149,13 @@ xfs_buffered_write_iomap_begin(
> * them out if the write happens to fail.
> */
> seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
> - xfs_iunlock(ip, XFS_ILOCK_EXCL);
> + xfs_iunlock(ip, lockmode);
> trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
> return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq);
>
> found_imap:
> seq = xfs_iomap_inode_sequence(ip, 0);
> - xfs_iunlock(ip, XFS_ILOCK_EXCL);
> + xfs_iunlock(ip, lockmode);
> return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
>
> found_cow:
> @@ -1165,17 +1165,17 @@ xfs_buffered_write_iomap_begin(
> if (error)
> goto out_unlock;
> seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
> - xfs_iunlock(ip, XFS_ILOCK_EXCL);
> + xfs_iunlock(ip, lockmode);
> return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
> IOMAP_F_SHARED, seq);
> }
>
> xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
> - xfs_iunlock(ip, XFS_ILOCK_EXCL);
> + xfs_iunlock(ip, lockmode);
> return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq);
>
> out_unlock:
> - xfs_iunlock(ip, XFS_ILOCK_EXCL);
> + xfs_iunlock(ip, lockmode);
> return error;
> }
>
> --
> 2.39.2
>
>
