Re: [PATCH v4 02/12] iomap: Rename IOMAP_ATOMIC -> IOMAP_ATOMIC_HW

[Christian Brauner <brauner@kernel.org>]

On Wed, Mar 05, 2025 at 01:57:26PM +0100, Carlos Maiolino wrote:
> Hi Christian,
> On Mon, Mar 03, 2025 at 05:11:10PM +0000, John Garry wrote:
> > In future xfs will support a SW-based atomic write, so rename
> > IOMAP_ATOMIC -> IOMAP_ATOMIC_HW to be clear which mode is being used.
> > 
> > Also relocate setting of IOMAP_ATOMIC_HW to the write path in
> > __iomap_dio_rw(), to be clear that this flag is only relevant to writes.
> > 
> > Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
> > Signed-off-by: John Garry <john.g.garry@oracle.com>
> 
> I pushed the patches in this series into this branch:
> git://git.kernel.org/pub/scm/fs/xfs/xfs-linux.git xfs-6.15-atomicwrites
> 
> Do you plan to send the iomap patches in this series yourself or is it ok with
> you if they go through xfs tree?

Ok, so this will have merge conflicts with vfs-6.15.iomap. I put the
preliminary iomap patches of this series onto vfs-6.15.iomap.

Please simply pull vfs-6.15.iomap instead of vfs-6.15.shared.iomap.
Nothing changes for you as everything has been kept stable. There'll be
no merge conflicts for us afterwards.

Thanks for the ping!

> 
> Cheers,
> Carlos
> 
> > ---
> >  Documentation/filesystems/iomap/operations.rst |  4 ++--
> >  fs/ext4/inode.c                                |  2 +-
> >  fs/iomap/direct-io.c                           | 18 +++++++++---------
> >  fs/iomap/trace.h                               |  2 +-
> >  include/linux/iomap.h                          |  2 +-
> >  5 files changed, 14 insertions(+), 14 deletions(-)
> > 
> > diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst
> > index d1535109587a..0b9d7be23bce 100644
> > --- a/Documentation/filesystems/iomap/operations.rst
> > +++ b/Documentation/filesystems/iomap/operations.rst
> > @@ -514,8 +514,8 @@ IOMAP_WRITE`` with any combination of the following enhancements:
> >     if the mapping is unwritten and the filesystem cannot handle zeroing
> >     the unaligned regions without exposing stale contents.
> > 
> > - * ``IOMAP_ATOMIC``: This write is being issued with torn-write
> > -   protection.
> > + * ``IOMAP_ATOMIC_HW``: This write is being issued with torn-write
> > +   protection based on HW-offload support.
> >     Only a single bio can be created for the write, and the write must
> >     not be split into multiple I/O requests, i.e. flag REQ_ATOMIC must be
> >     set.
> > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> > index 7c54ae5fcbd4..ba2f1e3db7c7 100644
> > --- a/fs/ext4/inode.c
> > +++ b/fs/ext4/inode.c
> > @@ -3467,7 +3467,7 @@ static inline bool ext4_want_directio_fallback(unsigned flags, ssize_t written)
> >  		return false;
> > 
> >  	/* atomic writes are all-or-nothing */
> > -	if (flags & IOMAP_ATOMIC)
> > +	if (flags & IOMAP_ATOMIC_HW)
> >  		return false;
> > 
> >  	/* can only try again if we wrote nothing */
> > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> > index e1e32e2bb0bf..c696ce980796 100644
> > --- a/fs/iomap/direct-io.c
> > +++ b/fs/iomap/direct-io.c
> > @@ -317,7 +317,7 @@ static int iomap_dio_zero(const struct iomap_iter *iter, struct iomap_dio *dio,
> >   * clearing the WRITE_THROUGH flag in the dio request.
> >   */
> >  static inline blk_opf_t iomap_dio_bio_opflags(struct iomap_dio *dio,
> > -		const struct iomap *iomap, bool use_fua, bool atomic)
> > +		const struct iomap *iomap, bool use_fua, bool atomic_hw)
> >  {
> >  	blk_opf_t opflags = REQ_SYNC | REQ_IDLE;
> > 
> > @@ -329,7 +329,7 @@ static inline blk_opf_t iomap_dio_bio_opflags(struct iomap_dio *dio,
> >  		opflags |= REQ_FUA;
> >  	else
> >  		dio->flags &= ~IOMAP_DIO_WRITE_THROUGH;
> > -	if (atomic)
> > +	if (atomic_hw)
> >  		opflags |= REQ_ATOMIC;
> > 
> >  	return opflags;
> > @@ -340,8 +340,8 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio)
> >  	const struct iomap *iomap = &iter->iomap;
> >  	struct inode *inode = iter->inode;
> >  	unsigned int fs_block_size = i_blocksize(inode), pad;
> > +	bool atomic_hw = iter->flags & IOMAP_ATOMIC_HW;
> >  	const loff_t length = iomap_length(iter);
> > -	bool atomic = iter->flags & IOMAP_ATOMIC;
> >  	loff_t pos = iter->pos;
> >  	blk_opf_t bio_opf;
> >  	struct bio *bio;
> > @@ -351,7 +351,7 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio)
> >  	u64 copied = 0;
> >  	size_t orig_count;
> > 
> > -	if (atomic && length != fs_block_size)
> > +	if (atomic_hw && length != fs_block_size)
> >  		return -EINVAL;
> > 
> >  	if ((pos | length) & (bdev_logical_block_size(iomap->bdev) - 1) ||
> > @@ -428,7 +428,7 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio)
> >  			goto out;
> >  	}
> > 
> > -	bio_opf = iomap_dio_bio_opflags(dio, iomap, use_fua, atomic);
> > +	bio_opf = iomap_dio_bio_opflags(dio, iomap, use_fua, atomic_hw);
> > 
> >  	nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, BIO_MAX_VECS);
> >  	do {
> > @@ -461,7 +461,7 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio)
> >  		}
> > 
> >  		n = bio->bi_iter.bi_size;
> > -		if (WARN_ON_ONCE(atomic && n != length)) {
> > +		if (WARN_ON_ONCE(atomic_hw && n != length)) {
> >  			/*
> >  			 * This bio should have covered the complete length,
> >  			 * which it doesn't, so error. We may need to zero out
> > @@ -652,9 +652,6 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> >  	if (iocb->ki_flags & IOCB_NOWAIT)
> >  		iomi.flags |= IOMAP_NOWAIT;
> > 
> > -	if (iocb->ki_flags & IOCB_ATOMIC)
> > -		iomi.flags |= IOMAP_ATOMIC;
> > -
> >  	if (iov_iter_rw(iter) == READ) {
> >  		/* reads can always complete inline */
> >  		dio->flags |= IOMAP_DIO_INLINE_COMP;
> > @@ -689,6 +686,9 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> >  			iomi.flags |= IOMAP_OVERWRITE_ONLY;
> >  		}
> > 
> > +		if (iocb->ki_flags & IOCB_ATOMIC)
> > +			iomi.flags |= IOMAP_ATOMIC_HW;
> > +
> >  		/* for data sync or sync, we need sync completion processing */
> >  		if (iocb_is_dsync(iocb)) {
> >  			dio->flags |= IOMAP_DIO_NEED_SYNC;
> > diff --git a/fs/iomap/trace.h b/fs/iomap/trace.h
> > index 9eab2c8ac3c5..69af89044ebd 100644
> > --- a/fs/iomap/trace.h
> > +++ b/fs/iomap/trace.h
> > @@ -99,7 +99,7 @@ DEFINE_RANGE_EVENT(iomap_dio_rw_queued);
> >  	{ IOMAP_FAULT,		"FAULT" }, \
> >  	{ IOMAP_DIRECT,		"DIRECT" }, \
> >  	{ IOMAP_NOWAIT,		"NOWAIT" }, \
> > -	{ IOMAP_ATOMIC,		"ATOMIC" }
> > +	{ IOMAP_ATOMIC_HW,	"ATOMIC_HW" }
> > 
> >  #define IOMAP_F_FLAGS_STRINGS \
> >  	{ IOMAP_F_NEW,		"NEW" }, \
> > diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> > index ea29388b2fba..87cd7079aaf3 100644
> > --- a/include/linux/iomap.h
> > +++ b/include/linux/iomap.h
> > @@ -189,7 +189,7 @@ struct iomap_folio_ops {
> >  #else
> >  #define IOMAP_DAX		0
> >  #endif /* CONFIG_FS_DAX */
> > -#define IOMAP_ATOMIC		(1 << 9)
> > +#define IOMAP_ATOMIC_HW		(1 << 9)
> >  #define IOMAP_DONTCACHE		(1 << 10)
> > 
> >  struct iomap_ops {
> > --
> > 2.31.1
> >