Btrfs: detect corrupted filesystem after write I/O errors

In check-integrity, detect when a superblock is written that points
to blocks that have not been written to disk due to I/O write errors.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>

1 files changed, 14 insertions, 2 deletions

diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 9197e2e33407..5a3e45db642a 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -37,8 +37,9 @@
  *        the file system was mounted, (i.e., they have been
  *        referenced by the super block) or they have been
  *        written since then and the write completion callback
- *        was called and a FLUSH request to the device where
- *        these blocks are located was received and completed.
+ *        was called and no write error was indicated and a
+ *        FLUSH request to the device where these blocks are
+ *        located was received and completed.
  *    2b. All referenced blocks need to have a generation
  *        number which is equal to the parent's number.
  *
@@ -2601,6 +2602,17 @@ static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
                                (unsigned long long)l->block_ref_to->dev_bytenr,
                                l->block_ref_to->mirror_num);
                         ret = -1;
+                } else if (l->block_ref_to->iodone_w_error) {
+                        printk(KERN_INFO "btrfs: attempt to write superblock"
+                               " which references block %c @%llu (%s/%llu/%d)"
+                               " which has write error!\n",
+                               btrfsic_get_block_type(state, l->block_ref_to),
+                               (unsigned long long)
+                               l->block_ref_to->logical_bytenr,
+                               l->block_ref_to->dev_state->name,
+                               (unsigned long long)l->block_ref_to->dev_bytenr,
+                               l->block_ref_to->mirror_num);
+                        ret = -1;
                 } else if (l->parent_generation !=
                            l->block_ref_to->generation &&
                            BTRFSIC_GENERATION_UNKNOWN !=