From 4ef3440174881b2fe5df2734843eddb2984ce73c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 27 Oct 2023 09:58:24 +0200 Subject: [PATCH] xfs: refine the unaligned check for always COW inodes in xfs_file_dio_write For always COW inodes we also must check the alignment of each individual iovec segment, as they could end up with different I/Os due to the way bio_iov_iter_get_pages works, and we'd then overwrite an already written block. The existing always_cow sysctl based code doesn't catch this because nothing enforces that blocks aren't rewritten, but for zoned XFS on sequential write required zones this is a hard error. Signed-off-by: Christoph Hellwig Reviewed-by: "Darrick J. Wong" --- fs/xfs/xfs_file.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 785f6bbf1406..d88a771d4c23 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -721,7 +721,16 @@ xfs_file_dio_write( /* direct I/O must be aligned to device logical sector size */ if ((iocb->ki_pos | count) & target->bt_logical_sectormask) return -EINVAL; - if ((iocb->ki_pos | count) & ip->i_mount->m_blockmask) + + /* + * For always COW inodes we also must check the alignment of each + * individual iovec segment, as they could end up with different + * I/Os due to the way bio_iov_iter_get_pages works, and we'd + * then overwrite an already written block. + */ + if (((iocb->ki_pos | count) & ip->i_mount->m_blockmask) || + (xfs_is_always_cow_inode(ip) && + (iov_iter_alignment(from) & ip->i_mount->m_blockmask))) return xfs_file_dio_write_unaligned(ip, iocb, from); return xfs_file_dio_write_aligned(ip, iocb, from); } -- 2.50.1