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

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[ Upstream commit 6d3113a193 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Omar Sandoval
2020-04-16 14:46:12 -07:00
committed by Chris
parent 241ecd43a3
commit 173d7d2574
1 changed files with 3 additions and 3 deletions
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6
fs/btrfs/inode.c
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@@ -8494,7 +8494,6 @@ static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip,
bio->bi_private = dip;
bio->bi_end_io = btrfs_end_dio_bio;
btrfs_io_bio(bio)->logical = file_offset;
atomic_inc(&dip->pending_bios);
while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
nr_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info, bvec->bv_len);
@@ -8560,7 +8559,8 @@ submit:
if (!ret)
return 0;
bio_put(bio);
if (bio != orig_bio)
bio_put(bio);
out_err:
dip->errors = 1;
/*
@@ -8607,7 +8607,7 @@ static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
io_bio->bi_private = dip;
dip->orig_bio = io_bio;
dip->dio_bio = dio_bio;
atomic_set(&dip->pending_bios, 0);
atomic_set(&dip->pending_bios, 1);
btrfs_bio = btrfs_io_bio(io_bio);
btrfs_bio->logical = file_offset;