btrfs: replace BUG_ON() in btrfs_csum_one_bio() with proper error handling

There is a BUG_ON() in btrfs_csum_one_bio() to catch code logic error.
It has indeed caught several bugs during subpage development.
But the BUG_ON() itself will bring down the whole system which is
an overkill.

Replace it with a WARN() and exit gracefully, so that it won't crash the
whole system while we can still catch the code logic error.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 2673c6b..0b9401a 100644 (file)
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -665,7 +665,18 @@ blk_status_t btrfs_csum_one_bio(struct btrfs_inode *inode, struct bio *bio,
 
                if (!ordered) {
                        ordered = btrfs_lookup_ordered_extent(inode, offset);
-                       BUG_ON(!ordered); /* Logic error */
+                       /*
+                        * The bio range is not covered by any ordered extent,
+                        * must be a code logic error.
+                        */
+                       if (unlikely(!ordered)) {
+                               WARN(1, KERN_WARNING
+                       "no ordered extent for root %llu ino %llu offset %llu\n",
+                                    inode->root->root_key.objectid,
+                                    btrfs_ino(inode), offset);
+                               kvfree(sums);
+                               return BLK_STS_IOERR;
+                       }
                }
 
                nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info,