* Re: [PATCH v3 3/4] fs: make _submit_bh consistent with generic bio chaining
2015-04-23 23:04 ` [PATCH v3 3/4] fs: make _submit_bh consistent with generic bio chaining Ming Lin
@ 2015-04-24 7:25 ` Christoph Hellwig
0 siblings, 0 replies; 2+ messages in thread
From: Christoph Hellwig @ 2015-04-24 7:25 UTC (permalink / raw)
To: Ming Lin
Cc: linux-kernel, Christoph Hellwig, Kent Overstreet, Jens Axboe,
Dongsu Park, Al Viro, linux-fsdevel
On Thu, Apr 23, 2015 at 04:04:34PM -0700, Ming Lin wrote:
> From: Kent Overstreet <kent.overstreet@gmail.com>
>
> Make _submit_bh() handle refcounting by increasing bio->bi_remaining,
> followed by bio_endio(). Since bio chaining was introduced with
> 196d38bccfcf ("block: Generic bio chaining"), refcounting should be
> done on bi_remaining instead of ancient bio_cnt. Doing that, calling
> convention can be consistent with the immutable biovecs API.
I think this and the copy & paste version in nilfs2 can just go away.
Since the big barrier to flush rewrite we will never fail FUA
and FLUSH requests with BIO_EOPNOTSUPP. That error is just left
for DISCARD adn WRITE_SAME. So something like the untested patch
below should take care of this:
diff --git a/block/bounce.c b/block/bounce.c
index ab21ba2..4bac725 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -128,9 +128,6 @@ static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
struct bio_vec *bvec, *org_vec;
int i;
- if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
- set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
-
/*
* free up bounce indirect pages used
*/
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 639f266..e8d7670 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3225,11 +3225,8 @@ static int write_dev_supers(struct btrfs_device *device,
*/
static void btrfs_end_empty_barrier(struct bio *bio, int err)
{
- if (err) {
- if (err == -EOPNOTSUPP)
- set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
+ if (err)
clear_bit(BIO_UPTODATE, &bio->bi_flags);
- }
if (bio->bi_private)
complete(bio->bi_private);
bio_put(bio);
@@ -3257,11 +3254,7 @@ static int write_dev_flush(struct btrfs_device *device, int wait)
wait_for_completion(&device->flush_wait);
- if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
- printk_in_rcu("BTRFS: disabling barriers on dev %s\n",
- rcu_str_deref(device->name));
- device->nobarriers = 1;
- } else if (!bio_flagged(bio, BIO_UPTODATE)) {
+ if (!bio_flagged(bio, BIO_UPTODATE)) {
ret = -EIO;
btrfs_dev_stat_inc_and_print(device,
BTRFS_DEV_STAT_FLUSH_ERRS);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index d688cfe..6a44bea 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2767,8 +2767,6 @@ static int __must_check submit_one_bio(int rw, struct bio *bio,
else
btrfsic_submit_bio(rw, bio);
- if (bio_flagged(bio, BIO_EOPNOTSUPP))
- ret = -EOPNOTSUPP;
bio_put(bio);
return ret;
}
diff --git a/fs/buffer.c b/fs/buffer.c
index c7a5602..efd85e0 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2938,10 +2938,6 @@ static void end_bio_bh_io_sync(struct bio *bio, int err)
{
struct buffer_head *bh = bio->bi_private;
- if (err == -EOPNOTSUPP) {
- set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
- }
-
if (unlikely (test_bit(BIO_QUIET,&bio->bi_flags)))
set_bit(BH_Quiet, &bh->b_state);
@@ -3041,13 +3037,7 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)
if (buffer_prio(bh))
rw |= REQ_PRIO;
- bio_get(bio);
submit_bio(rw, bio);
-
- if (bio_flagged(bio, BIO_EOPNOTSUPP))
- ret = -EOPNOTSUPP;
-
- bio_put(bio);
return ret;
}
EXPORT_SYMBOL_GPL(_submit_bh);
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 5765f88..c5d81e8 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -359,7 +359,6 @@ void ext4_io_submit(struct ext4_io_submit *io)
if (bio) {
bio_get(io->io_bio);
submit_bio(io->io_op, io->io_bio);
- BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP));
bio_put(io->io_bio);
}
io->io_bio = NULL;
diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index dc3a9efd..42468e5 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -343,11 +343,6 @@ static void nilfs_end_bio_write(struct bio *bio, int err)
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct nilfs_segment_buffer *segbuf = bio->bi_private;
- if (err == -EOPNOTSUPP) {
- set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
- /* to be detected by nilfs_segbuf_submit_bio() */
- }
-
if (!uptodate)
atomic_inc(&segbuf->sb_err);
@@ -374,15 +369,8 @@ static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
bio->bi_end_io = nilfs_end_bio_write;
bio->bi_private = segbuf;
- bio_get(bio);
submit_bio(mode, bio);
segbuf->sb_nbio++;
- if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
- bio_put(bio);
- err = -EOPNOTSUPP;
- goto failed;
- }
- bio_put(bio);
wi->bio = NULL;
wi->rest_blocks -= wi->end - wi->start;
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index a1b25e3..809feb3 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -118,7 +118,6 @@ struct bio {
#define BIO_CLONED 4 /* doesn't own data */
#define BIO_BOUNCED 5 /* bio is a bounce bio */
#define BIO_USER_MAPPED 6 /* contains user pages */
-#define BIO_EOPNOTSUPP 7 /* not supported */
#define BIO_NULL_MAPPED 8 /* contains invalid user pages */
#define BIO_QUIET 9 /* Make BIO Quiet */
#define BIO_SNAP_STABLE 10 /* bio data must be snapshotted during write */
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