From 6d3113a193e3385c72240096fe397618ecab6e43 Mon Sep 17 00:00:00 2001 From: Omar Sandoval 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@vger.kernel.org # 4.4+ Reviewed-by: Nikolay Borisov Reviewed-by: Josef Bacik Reviewed-by: Johannes Thumshirn Signed-off-by: Omar Sandoval Signed-off-by: David Sterba --- fs/btrfs/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 259239b..b628c31 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 @@ 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; -- 2.7.4