From: Filipe Manana fdmanana@suse.com

commit e0391e92f9ab4fb3dbdeb139c967dcfa7ac4b115 upstream.

If we do a direct IO sync write, at btrfs_sync_file(), and we need to skip inode logging or we get an error starting a transaction or an error when flushing delalloc, we end up unlocking the inode when we shouldn't under the 'out_release_extents' label, and then unlock it again at btrfs_direct_write().

Fix that by checking if we have to skip inode unlocking under that label.

Reported-by: syzbot+7dbbb74af6291b5a5a8b@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/000000000000dfd631061eaeb4bc@google.com/ Fixes: 939b656bc8ab ("btrfs: fix corruption after buffer fault in during direct IO append write") Reviewed-by: Josef Bacik josef@toxicpanda.com Signed-off-by: Filipe Manana fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com --- fs/btrfs/file.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index a47a7bbf9b7e..952cf145c629 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2038,7 +2038,10 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)

out_release_extents: btrfs_release_log_ctx_extents(&ctx); - btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP); + if (skip_ilock) + up_write(&BTRFS_I(inode)->i_mmap_lock); + else + btrfs_inode_unlock(BTRFS_I(inode), BTRFS_ILOCK_MMAP); goto out; }