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Commit a95236d9 authored by Jan Schmidt's avatar Jan Schmidt
Browse files

Btrfs: fix return value for __tree_mod_log_oldest_root 



In __tree_mod_log_oldest_root() we must return the found operation even if
it's not a ROOT_REPLACE operation. Otherwise, the caller assumes that there
are no operations to be rewinded and returns immediately.

The code in the caller is modified to improve readability.

Signed-off-by: default avatarJan Schmidt <list.btrfs@jan-o-sch.net>
parent 8ba97a15

fs/btrfs/ctree.c

+20 −13
Original line number Original line Diff line number Diff line
@@ -1023,6 +1023,10 @@ __tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info, 
		looped = 1;

		looped = 1;

	}

	}





	/* if there's no old root to return, return what we found instead */

	if (!found)

		found = tm;



	return found;

	return found;

}

}
@@ -1155,18 +1159,24 @@ get_old_root(struct btrfs_root *root, u64 time_seq) 
{

{

	struct tree_mod_elem *tm;

	struct tree_mod_elem *tm;

	struct extent_buffer *eb;

	struct extent_buffer *eb;

	struct tree_mod_root *old_root;

	struct tree_mod_root *old_root = NULL;

	u64 old_generation;

	u64 old_generation;

	u64 logical;





	eb = btrfs_read_lock_root_node(root);

	eb = btrfs_read_lock_root_node(root);

	tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);

	tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);

	if (!tm)

	if (!tm)

		return root->node;

		return root->node;





	if (tm->op == MOD_LOG_ROOT_REPLACE) {

		old_root = &tm->old_root;

		old_root = &tm->old_root;

		old_generation = tm->generation;

		old_generation = tm->generation;

		logical = old_root->logical;

	} else {

		logical = root->node->start;

	}





	tm = tree_mod_log_search(root->fs_info, old_root->logical, time_seq);

	tm = tree_mod_log_search(root->fs_info, logical, time_seq);

	/*

	/*

	 * there was an item in the log when __tree_mod_log_oldest_root

	 * there was an item in the log when __tree_mod_log_oldest_root

	 * returned. this one must not go away, because the time_seq passed to

	 * returned. this one must not go away, because the time_seq passed to
@@ -1174,26 +1184,23 @@ get_old_root(struct btrfs_root *root, u64 time_seq) 
	 */

	 */

	BUG_ON(!tm);

	BUG_ON(!tm);





	if (old_root->logical == root->node->start) {

	if (old_root)

		/* there are logged operations for the current root */

		eb = btrfs_clone_extent_buffer(root->node);

	} else {

		/* there's a root replace operation for the current root */

		eb = alloc_dummy_extent_buffer(tm->index << PAGE_CACHE_SHIFT,

		eb = alloc_dummy_extent_buffer(tm->index << PAGE_CACHE_SHIFT,

					       root->nodesize);

					       root->nodesize);

	}

	else

		eb = btrfs_clone_extent_buffer(root->node);

	btrfs_tree_read_unlock(root->node);

	btrfs_tree_read_unlock(root->node);

	free_extent_buffer(root->node);

	free_extent_buffer(root->node);

	if (!eb)

	if (!eb)

		return NULL;

		return NULL;

	btrfs_tree_read_lock(eb);

	btrfs_tree_read_lock(eb);

	if (old_root->logical != root->node->start) {

	if (old_root) {

		btrfs_set_header_bytenr(eb, eb->start);

		btrfs_set_header_bytenr(eb, eb->start);

		btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);

		btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);

		btrfs_set_header_owner(eb, root->root_key.objectid);

		btrfs_set_header_owner(eb, root->root_key.objectid);

	}

		btrfs_set_header_level(eb, old_root->level);

		btrfs_set_header_level(eb, old_root->level);

		btrfs_set_header_generation(eb, old_generation);

		btrfs_set_header_generation(eb, old_generation);

	}

	__tree_mod_log_rewind(eb, time_seq, tm);

	__tree_mod_log_rewind(eb, time_seq, tm);

	extent_buffer_get(eb);

	extent_buffer_get(eb);