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Commit cb44921a authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: don't loop forever on bad btree blocks 



When btrfs discovers the generation number in a btree block is
incorrect, it can loop forever without forcing the RAID
code to try a valid mirror, and without returning EIO.

This changes things to properly kick out the EIO.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 6b5b817f

fs/btrfs/ctree.c

+28 −9
Original line number Diff line number Diff line
@@ -1577,14 +1577,34 @@ read_block_for_search(struct btrfs_trans_handle *trans, 
	blocksize = btrfs_level_size(root, level - 1);



	tmp = btrfs_find_tree_block(root, blocknr, blocksize);

	if (tmp && btrfs_buffer_uptodate(tmp, gen)) {

	if (tmp) {

		if (btrfs_buffer_uptodate(tmp, 0)) {

			if (btrfs_buffer_uptodate(tmp, gen)) {

				/*

		 * we found an up to date block without sleeping, return

				 * we found an up to date block without

				 * sleeping, return

				 * right away

				 */

				*eb_ret = tmp;

				return 0;

			}

			/* the pages were up to date, but we failed

			 * the generation number check.  Do a full

			 * read for the generation number that is correct.

			 * We must do this without dropping locks so

			 * we can trust our generation number

			 */

			free_extent_buffer(tmp);

			tmp = read_tree_block(root, blocknr, blocksize, gen);

			if (tmp && btrfs_buffer_uptodate(tmp, gen)) {

				*eb_ret = tmp;

				return 0;

			}

			free_extent_buffer(tmp);

			btrfs_release_path(NULL, p);

			return -EIO;

		}

	}



	/*

	 * reduce lock contention at high levels
@@ -1596,7 +1616,6 @@ read_block_for_search(struct btrfs_trans_handle *trans, 
	btrfs_unlock_up_safe(p, level + 1);

	btrfs_set_path_blocking(p);



	if (tmp)

	free_extent_buffer(tmp);

	if (p->reada)

		reada_for_search(root, p, level, slot, key->objectid);