Commit 57a304cf authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: do not panic in __add_reloc_root 



If we have a duplicate entry for a reloc root then we could have fs
corruption that resulted in a double allocation.  Since this shouldn't
happen unless there is corruption, add an ASSERT(ret != -EEXIST) to all
of the callers of __add_reloc_root() to catch any logic mistakes for
developers, otherwise normal error handling will happen for normal
users.

Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 3c925863

fs/btrfs/relocation.c

+5 −1
Original line number Diff line number Diff line
@@ -638,9 +638,10 @@ static int __must_check __add_reloc_root(struct btrfs_root *root) 
				   node->bytenr, &node->rb_node);

	spin_unlock(&rc->reloc_root_tree.lock);

	if (rb_node) {

		btrfs_panic(fs_info, -EEXIST,

		btrfs_err(fs_info,

			    "Duplicate root found for start=%llu while inserting into relocation tree",

			    node->bytenr);

		return -EEXIST;

	}



	list_add_tail(&root->root_list, &rc->reloc_roots);
@@ -882,6 +883,7 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, 
		return PTR_ERR(reloc_root);



	ret = __add_reloc_root(reloc_root);

	ASSERT(ret != -EEXIST);

	if (ret) {

		/* Pairs with create_reloc_root */

		btrfs_put_root(reloc_root);
@@ -4059,6 +4061,7 @@ int btrfs_recover_relocation(struct btrfs_root *root) 
		}



		err = __add_reloc_root(reloc_root);

		ASSERT(err != -EEXIST);

		if (err) {

			list_add_tail(&reloc_root->root_list, &reloc_roots);

			btrfs_put_root(fs_root);
@@ -4279,6 +4282,7 @@ int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans, 
		return PTR_ERR(reloc_root);



	ret = __add_reloc_root(reloc_root);

	ASSERT(ret != -EEXIST);

	if (ret) {

		/* Pairs with create_reloc_root */

		btrfs_put_root(reloc_root);