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btrfs: fix error handling when submitting direct I/O bio

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In btrfs_submit_direct_hook(), if a direct I/O write doesn't span a RAID
stripe or chunk, we submit orig_bio without cloning it. In this case, we
don't increment pending_bios. Then, if btrfs_submit_dio_bio() fails, we
decrement pending_bios to -1, and we never complete orig_bio. Fix it by
initializing pending_bios to 1 instead of incrementing later.

Fixing this exposes another bug: we put orig_bio prematurely and then
put it again from end_io. Fix it by not putting orig_bio.

After this change, pending_bios is really more of a reference count, but
I'll leave that cleanup separate to keep the fix small.

Fixes: e65e153554 ("btrfs: fix panic caused by direct IO")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Omar Sandoval 2020-04-16 14:46:12 -07:00 committed by David Sterba
parent 1072c12d7d
commit 6d3113a193
1 changed files with 3 additions and 3 deletions
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6
fs/btrfs/inode.c
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@ -7939,7 +7939,6 @@ static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip)
/* bio split */
ASSERT(geom.len <= INT_MAX);
atomic_inc(&dip->pending_bios);
do {
clone_len = min_t(int, submit_len, geom.len);
@ -7989,7 +7988,8 @@ submit:
if (!status)
return 0;
bio_put(bio);
if (bio != orig_bio)
bio_put(bio);
out_err:
dip->errors = 1;
/*
@ -8030,7 +8030,7 @@ static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
bio->bi_private = dip;
dip->orig_bio = bio;
dip->dio_bio = dio_bio;
atomic_set(&dip->pending_bios, 0);
atomic_set(&dip->pending_bios, 1);
io_bio = btrfs_io_bio(bio);
io_bio->logical = file_offset;