From: John Garry <john.g.garry@oracle.com> mainline inclusion from mainline-v6.12-rc1 commit 9e0933c21c128d6d8ac4d8aae0babaf9a43100b8 category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/8862 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Support direct I/O atomic writes by producing a single bio with REQ_ATOMIC flag set. Initially FSes (XFS) should only support writing a single FS block atomically. As with any atomic write, we should produce a single bio which covers the complete write length. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> [djwong: clarify a couple of things in the docs] Signed-off-by: Darrick J. Wong <djwong@kernel.org> Conflicts: Documentation/filesystems/iomap/operations.rst Signed-off-by: Long Li <leo.lilong@huawei.com> --- fs/iomap/direct-io.c | 38 ++++++++++++++++++++++++++++++++++---- fs/iomap/trace.h | 3 ++- include/linux/iomap.h | 1 + 3 files changed, 37 insertions(+), 5 deletions(-) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index bcd3f8cf5ea4..2cc95448b97a 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -256,7 +256,7 @@ static void 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) + const struct iomap *iomap, bool use_fua, bool atomic) { blk_opf_t opflags = REQ_SYNC | REQ_IDLE; @@ -268,6 +268,8 @@ 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) + opflags |= REQ_ATOMIC; return opflags; } @@ -278,7 +280,8 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, const struct iomap *iomap = &iter->iomap; struct inode *inode = iter->inode; unsigned int fs_block_size = i_blocksize(inode), pad; - loff_t length = iomap_length(iter); + 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; @@ -288,6 +291,9 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, size_t copied = 0; size_t orig_count; + if (atomic && length != fs_block_size) + return -EINVAL; + if ((pos | length) & (bdev_logical_block_size(iomap->bdev) - 1) || !bdev_iter_is_aligned(iomap->bdev, dio->submit.iter)) return -EINVAL; @@ -365,7 +371,7 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, * can set up the page vector appropriately for a ZONE_APPEND * operation. */ - bio_opf = iomap_dio_bio_opflags(dio, iomap, use_fua); + bio_opf = iomap_dio_bio_opflags(dio, iomap, use_fua, atomic); nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, BIO_MAX_VECS); do { @@ -397,6 +403,17 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter, } n = bio->bi_iter.bi_size; + if (WARN_ON_ONCE(atomic && n != length)) { + /* + * This bio should have covered the complete length, + * which it doesn't, so error. We may need to zero out + * the tail (complete FS block), similar to when + * bio_iov_iter_get_pages() returns an error, above. + */ + ret = -EINVAL; + bio_put(bio); + goto zero_tail; + } if (dio->flags & IOMAP_DIO_WRITE) { task_io_account_write(n); } else { @@ -579,6 +596,9 @@ __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; @@ -640,7 +660,17 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (ret != -EAGAIN) { trace_iomap_dio_invalidate_fail(inode, iomi.pos, iomi.len); - ret = -ENOTBLK; + if (iocb->ki_flags & IOCB_ATOMIC) { + /* + * folio invalidation failed, maybe + * this is transient, unlock and see if + * the caller tries again. + */ + ret = -EAGAIN; + } else { + /* fall back to buffered write */ + ret = -ENOTBLK; + } } goto out_free_dio; } diff --git a/fs/iomap/trace.h b/fs/iomap/trace.h index 3ef694f9489f..65d7a58465f0 100644 --- a/fs/iomap/trace.h +++ b/fs/iomap/trace.h @@ -98,7 +98,8 @@ DEFINE_RANGE_EVENT(iomap_dio_rw_queued); { IOMAP_REPORT, "REPORT" }, \ { IOMAP_FAULT, "FAULT" }, \ { IOMAP_DIRECT, "DIRECT" }, \ - { IOMAP_NOWAIT, "NOWAIT" } + { IOMAP_NOWAIT, "NOWAIT" }, \ + { IOMAP_ATOMIC, "ATOMIC" } #define IOMAP_F_FLAGS_STRINGS \ { IOMAP_F_NEW, "NEW" }, \ diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 6bd7ed98cf1f..85ada1f1b131 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -178,6 +178,7 @@ struct iomap_folio_ops { #else #define IOMAP_DAX 0 #endif /* CONFIG_FS_DAX */ +#define IOMAP_ATOMIC (1 << 9) struct iomap_ops { /* -- 2.39.2