btrfs: abort transaction on generation mismatch when marking eb as dirty

When marking an extent buffer as dirty, at btrfs_mark_buffer_dirty(),
we check if its generation matches the running transaction and if not we
just print a warning. Such mismatch is an indicator that something really
went wrong and only printing a warning message (and stack trace) is not
enough to prevent a corruption. Allowing a transaction to commit with such
an extent buffer will trigger an error if we ever try to read it from disk
due to a generation mismatch with its parent generation.

So abort the current transaction with -EUCLEAN if we notice a generation
mismatch. For this we need to pass a transaction handle to
btrfs_mark_buffer_dirty() which is always available except in test code,
in which case we can pass NULL since it operates on dummy extent buffers
and all test roots have a single node/leaf (root node at level 0).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 9 insertions, 8 deletions

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 1ce5dd154499..45cae356e89b 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -194,7 +194,7 @@ int btrfs_insert_hole_extent(struct btrfs_trans_handle *trans,
 	btrfs_set_file_extent_encryption(leaf, item, 0);
 	btrfs_set_file_extent_other_encoding(leaf, item, 0);
 
-	btrfs_mark_buffer_dirty(leaf);
+	btrfs_mark_buffer_dirty(trans, leaf);
 out:
 	btrfs_free_path(path);
 	return ret;
@@ -811,11 +811,12 @@ blk_status_t btrfs_alloc_dummy_sum(struct btrfs_bio *bbio)
  * This calls btrfs_truncate_item with the correct args based on the overlap,
  * and fixes up the key as required.
  */
-static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info,
+static noinline void truncate_one_csum(struct btrfs_trans_handle *trans,
 				       struct btrfs_path *path,
 				       struct btrfs_key *key,
 				       u64 bytenr, u64 len)
 {
+	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct extent_buffer *leaf;
 	const u32 csum_size = fs_info->csum_size;
 	u64 csum_end;
@@ -836,7 +837,7 @@ static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info,
 		 */
 		u32 new_size = (bytenr - key->offset) >> blocksize_bits;
 		new_size *= csum_size;
-		btrfs_truncate_item(path, new_size, 1);
+		btrfs_truncate_item(trans, path, new_size, 1);
 	} else if (key->offset >= bytenr && csum_end > end_byte &&
 		   end_byte > key->offset) {
 		/*
@@ -848,10 +849,10 @@ static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info,
 		u32 new_size = (csum_end - end_byte) >> blocksize_bits;
 		new_size *= csum_size;
 
-		btrfs_truncate_item(path, new_size, 0);
+		btrfs_truncate_item(trans, path, new_size, 0);
 
 		key->offset = end_byte;
-		btrfs_set_item_key_safe(fs_info, path, key);
+		btrfs_set_item_key_safe(trans, path, key);
 	} else {
 		BUG();
 	}
@@ -994,7 +995,7 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
 
 			key.offset = end_byte - 1;
 		} else {
-			truncate_one_csum(fs_info, path, &key, bytenr, len);
+			truncate_one_csum(trans, path, &key, bytenr, len);
 			if (key.offset < bytenr)
 				break;
 		}
@@ -1202,7 +1203,7 @@ extend_csum:
 		diff /= csum_size;
 		diff *= csum_size;
 
-		btrfs_extend_item(path, diff);
+		btrfs_extend_item(trans, path, diff);
 		ret = 0;
 		goto csum;
 	}
@@ -1249,7 +1250,7 @@ found:
 	ins_size /= csum_size;
 	total_bytes += ins_size * fs_info->sectorsize;
 
-	btrfs_mark_buffer_dirty(path->nodes[0]);
+	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 	if (total_bytes < sums->len) {
 		btrfs_release_path(path);
 		cond_resched();