The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 6d3113a193e3385c72240096fe397618ecab6e43 Mon Sep 17 00:00:00 2001
From: Omar Sandoval <osandov@xxxxxx>
Date: Thu, 16 Apr 2020 14:46:12 -0700
Subject: [PATCH] btrfs: fix error handling when submitting direct I/O bio
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: e65e15355429 ("btrfs: fix panic caused by direct IO")
CC: stable@xxxxxxxxxxxxxxx # 4.4+
Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 259239b33370..b628c319a5b6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -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 @@ static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip)
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;
