| Message ID | 20241211085636.1380516-13-hch@lst.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [01/43] xfs: constify feature checks | expand |
On Wed, Dec 11, 2024 at 09:54:37AM +0100, Christoph Hellwig wrote: > 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. I'm not sure why an alwayscow inode now needs to require fsblock-aligned segments, seeing as it's been running mostly fine for years. Is this a bug fix? Or prep for rtzone files, which are (presumably) always written out of place? --D > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > 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 2b6d4c71994d..6bcfd4c34a37 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); > } > -- > 2.45.2 > >
On Thu, Dec 12, 2024 at 01:44:42PM -0800, Darrick J. Wong wrote: > On Wed, Dec 11, 2024 at 09:54:37AM +0100, Christoph Hellwig wrote: > > 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. > > I'm not sure why an alwayscow inode now needs to require fsblock-aligned > segments, seeing as it's been running mostly fine for years. Because the storage you test always_cow on doesn't actually force always_cow on you :) I.e. these segmented iovecs can end up overwriting a block. That's ok if you're on a conventional device, but it will error out on a sequential write required zoned.
On Fri, Dec 13, 2024 at 06:14:00AM +0100, Christoph Hellwig wrote: > On Thu, Dec 12, 2024 at 01:44:42PM -0800, Darrick J. Wong wrote: > > On Wed, Dec 11, 2024 at 09:54:37AM +0100, Christoph Hellwig wrote: > > > 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. > > > > I'm not sure why an alwayscow inode now needs to require fsblock-aligned > > segments, seeing as it's been running mostly fine for years. > > Because the storage you test always_cow on doesn't actually force > always_cow on you :) I.e. these segmented iovecs can end up overwriting > a block. That's ok if you're on a conventional device, but it will > error out on a sequential write required zoned. Fine with me then :) Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> --D
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 2b6d4c71994d..6bcfd4c34a37 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); }
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. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/xfs_file.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)