Re: [PATCH v5 6/7] xfs: Validate atomic writes
From: "Darrick J. Wong" <djwong@kernel.org>
Date: 2024-08-21 17:10:31
Also in:
linux-fsdevel, linux-xfs, lkml
On Sat, Aug 17, 2024 at 09:47:59AM +0000, John Garry wrote:
quoted hunk ↗ jump to hunk
Validate that an atomic write adheres to length/offset rules. Since we require extent alignment for atomic writes, this effectively also enforces that the BIO which iomap produces is aligned. For an IOCB with IOCB_ATOMIC set to get as far as xfs_file_dio_write(), FMODE_CAN_ATOMIC_WRITE will need to be set for the file; for this, FORCEALIGN and also ATOMICWRITES flags would also need to be set for the inode. Signed-off-by: John Garry <john.g.garry@oracle.com> --- fs/xfs/xfs_file.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 4cdc54dc9686..9b6530a4eb4a 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c@@ -684,9 +684,20 @@ xfs_file_dio_write( struct kiocb *iocb, struct iov_iter *from) { - struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp)); + struct inode *inode = file_inode(iocb->ki_filp); + struct xfs_inode *ip = XFS_I(inode); struct xfs_buftarg *target = xfs_inode_buftarg(ip); size_t count = iov_iter_count(from); + struct xfs_mount *mp = ip->i_mount; + + if (iocb->ki_flags & IOCB_ATOMIC) { + if (count < i_blocksize(inode)) + return -EINVAL; + if (count > XFS_FSB_TO_B(mp, ip->i_extsize)) + return -EINVAL;
Here's also the place to check the dynamic things like dalign/swidth alignment. Other than that, this looks good. --D
+ if (!generic_atomic_write_valid(iocb, from)) + return -EINVAL; + } /* direct I/O must be aligned to device logical sector size */ if ((iocb->ki_pos | count) & target->bt_logical_sectormask) -- 2.31.1