btrfs: Add graceful handling of V0 extents

Following the removal of the v0 handling code let's be courteous and
print an error message when such extents are handled. In the cases
where we have a transaction just abort it, otherwise just call
btrfs_handle_fs_error. Both cases result in the FS being re-mounted RO.

In case the error handling would be too intrusive, leave the BUG_ON in
place, like extent_data_ref_count, other proper handling would catch
that earlier.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 24 insertions, 3 deletions

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 6dfa92e5ceed..eaf59c742dc8 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -598,6 +598,11 @@ int find_inline_backref(struct extent_buffer *leaf, int slot,
         btrfs_item_key_to_cpu(leaf, &key, slot);
 
         item_size = btrfs_item_size_nr(leaf, slot);
+        if (item_size < sizeof(*ei)) {
+                btrfs_print_v0_err(leaf->fs_info);
+                btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL);
+                return 1;
+        }
         ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
         WARN_ON(!(btrfs_extent_flags(leaf, ei) &
                   BTRFS_EXTENT_FLAG_TREE_BLOCK));
@@ -782,7 +787,6 @@ again:
                         goto next;
                 }
 
-                ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
                 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
                         if (key.objectid == key.offset) {
                                 /*
@@ -826,6 +830,12 @@ again:
                         edge->node[UPPER] = upper;
 
                         goto next;
+                } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
+                        err = -EINVAL;
+                        btrfs_print_v0_err(rc->extent_root->fs_info);
+                        btrfs_handle_fs_error(rc->extent_root->fs_info, err,
+                                              NULL);
+                        goto out;
                 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
                         goto next;
                 }
@@ -3315,6 +3325,10 @@ static int add_tree_block(struct reloc_control *rc,
                         level = (int)extent_key->offset;
                 }
                 generation = btrfs_extent_generation(eb, ei);
+        } else if (item_size == sizeof(struct btrfs_extent_item_v0)) {
+                btrfs_print_v0_err(eb->fs_info);
+                btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
+                return -EINVAL;
         } else {
                 BUG();
         }
@@ -3720,7 +3734,6 @@ int add_data_references(struct reloc_control *rc,
                 if (key.objectid != extent_key->objectid)
                         break;
 
-                BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
                 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
                         ret = __add_tree_block(rc, key.offset, blocksize,
                                                blocks);
@@ -3729,6 +3742,10 @@ int add_data_references(struct reloc_control *rc,
                                               struct btrfs_extent_data_ref);
                         ret = find_data_references(rc, extent_key,
                                                    eb, dref, blocks);
+                } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
+                        btrfs_print_v0_err(eb->fs_info);
+                        btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
+                        ret = -EINVAL;
                 } else {
                         ret = 0;
                 }
@@ -3967,7 +3984,11 @@ restart:
                         flags = btrfs_extent_flags(path->nodes[0], ei);
                         ret = check_extent_flags(flags);
                         BUG_ON(ret);
-
+                } else if (item_size == sizeof(struct btrfs_extent_item_v0)) {
+                        err = -EINVAL;
+                        btrfs_print_v0_err(trans->fs_info);
+                        btrfs_abort_transaction(trans, err);
+                        break;
                 } else {
                         BUG();
                 }