btrfs: do not double complete bio on errors during compressed reads

I hit some weird panics while fixing up the error handling from
btrfs_lookup_bio_sums().  Turns out the compression path will complete
the bio we use if we set up any of the compression bios and then return
an error, and then btrfs_submit_data_bio() will also call bio_endio() on
the bio.

Fix this by making btrfs_submit_compressed_read() responsible for
calling bio_endio() on the bio if there are any errors.  Currently it
was only doing it if we created the compression bios, otherwise it was
depending on btrfs_submit_data_bio() to do the right thing.  This
creates the above problem, so fix up btrfs_submit_compressed_read() to
always call bio_endio() in case of an error, and then simply return from
btrfs_submit_data_bio() if we had to call
btrfs_submit_compressed_read().

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 964eab60742f..53f46d5c78c7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2543,10 +2543,15 @@ blk_status_t btrfs_submit_data_bio(struct inode *inode, struct bio *bio,
 			goto out;
 
 		if (bio_flags & EXTENT_BIO_COMPRESSED) {
+			/*
+			 * btrfs_submit_compressed_read will handle completing
+			 * the bio if there were any errors, so just return
+			 * here.
+			 */
 			ret = btrfs_submit_compressed_read(inode, bio,
 							   mirror_num,
 							   bio_flags);
-			goto out;
+			goto out_no_endio;
 		} else {
 			/*
 			 * Lookup bio sums does extra checks around whether we
@@ -2580,6 +2585,7 @@ out:
 		bio->bi_status = ret;
 		bio_endio(bio);
 	}
+out_no_endio:
 	return ret;
 }