Re: [Patch v9 07/10] block: Add fops atomic write support

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 6/20/24 14:53, John Garry wrote:
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.

Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>
---
  block/fops.c | 20 +++++++++++++++++---
  1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/block/fops.c b/block/fops.c
index 376265935714..be36c9fbd500 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -34,9 +34,12 @@ static blk_opf_t dio_bio_write_op(struct kiocb *iocb)
  	return opf;
  }
-static bool blkdev_dio_unaligned(struct block_device *bdev, loff_t pos,
-			      struct iov_iter *iter)
+static bool blkdev_dio_invalid(struct block_device *bdev, loff_t pos,
+				struct iov_iter *iter, bool is_atomic)
  {
+	if (is_atomic && !generic_atomic_write_valid(iter, pos))
+		return true;
+
  	return pos & (bdev_logical_block_size(bdev) - 1) ||
  		!bdev_iter_is_aligned(bdev, iter);
  }
@@ -72,6 +75,8 @@ static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
  	bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
  	bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
  	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))
@@ -343,6 +348,9 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *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;
@@ -359,12 +367,13 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
  static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
  {
  	struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
+	bool is_atomic = iocb->ki_flags & IOCB_ATOMIC;
  	unsigned int nr_pages;
if (!iov_iter_count(iter))
  		return 0;
- if (blkdev_dio_unaligned(bdev, iocb->ki_pos, iter))
+	if (blkdev_dio_invalid(bdev, iocb->ki_pos, iter, is_atomic))

Why not passing in iocb->ki_flags here?
Or, indeed, the entire iocb?

Cheers,

Hannes
--
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@xxxxxxx                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich





[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [NTFS 3]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [NTFS 3]     [Samba]     [Device Mapper]     [CEPH Development]

  Powered by Linux