From: John Garry john.g.garry@oracle.com
maillist inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I9VTE3 CVE: NA
Reference: https://lore.kernel.org/all/20240326133813.3224593-1-john.g.garry@oracle.com...
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Support atomic writes by submitting a single BIO with the REQ_ATOMIC set.
It must be ensured that the atomic write adheres to its rules, like naturally aligned offset, so call blkdev_dio_invalid() -> blkdev_atomic_write_valid() [with renaming blkdev_dio_unaligned() to blkdev_dio_invalid()] for this purpose. The BIO submission path currently checks for atomic writes which are too large, so no need to check here.
In blkdev_direct_IO(), if the nr_pages exceeds BIO_MAX_VECS, then we cannot produce a single BIO, so error in this case.
Finally set FMODE_CAN_ATOMIC_WRITE when the bdev can support atomic writes and the associated file flag is for O_DIRECT.
Signed-off-by: John Garry john.g.garry@oracle.com Signed-off-by: Long Li leo.lilong@huawei.com --- fs/block_dev.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c index b9104fc0a395..84060c7d80a1 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -272,6 +272,9 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter, bio.bi_end_io = blkdev_bio_end_io_simple; bio.bi_ioprio = iocb->ki_ioprio;
+ if (iocb->ki_flags & IOCB_ATOMIC) + bio.bi_opf |= REQ_ATOMIC; + ret = bio_iov_iter_get_pages(&bio, iter); if (unlikely(ret)) goto out; @@ -452,6 +455,10 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) bio->bi_opf = dio_bio_write_op(iocb); task_io_account_write(bio->bi_iter.bi_size); } + + if (iocb->ki_flags & IOCB_ATOMIC) + bio->bi_opf |= REQ_ATOMIC; + if (iocb->ki_flags & IOCB_NOWAIT) bio->bi_opf |= REQ_NOWAIT;
@@ -521,14 +528,30 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) return ret; }
+static bool blkdev_atomic_write_valid(struct block_device *bdev, loff_t pos, + struct iov_iter *iter) +{ + struct request_queue *q = bdev_get_queue(bdev); + unsigned int min_bytes = queue_atomic_write_unit_min_bytes(q); + unsigned int max_bytes = queue_atomic_write_unit_max_bytes(q); + + return generic_atomic_write_valid(pos, iter, min_bytes, max_bytes); +} + static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) { int nr_pages; + bool is_atomic = iocb->ki_flags & IOCB_ATOMIC; + struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES + 1); if (!nr_pages) return 0; + + if (is_atomic && !blkdev_atomic_write_valid(bdev, iocb->ki_pos, iter)) + return -EINVAL; + if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_PAGES) return __blkdev_direct_IO_simple(iocb, iter, nr_pages);
@@ -1863,6 +1886,7 @@ EXPORT_SYMBOL(blkdev_get_by_dev); static int blkdev_open(struct inode * inode, struct file * filp) { struct block_device *bdev; + int err;
/* * Preserve backwards compatibility and allow large file access @@ -1888,7 +1912,11 @@ static int blkdev_open(struct inode * inode, struct file * filp) filp->f_mapping = bdev->bd_inode->i_mapping; filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
- return blkdev_get(bdev, filp->f_mode, filp); + err = blkdev_get(bdev, filp->f_mode, filp); + if (!err && bdev_can_atomic_write(bdev) && filp->f_flags & O_DIRECT) + filp->f_mode |= FMODE_CAN_ATOMIC_WRITE; + + return err; }
static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)