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Commit 35bbb97f authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Chris Mason
Browse files

btrfs: don't create or leak aliased root while cleaning up orphans 



commit 909c3a22 (Btrfs: fix loading of orphan roots leading to BUG_ON)
avoids the BUG_ON but can add an aliased root to the dead_roots list or
leak the root.

Since we've already been loading roots into the radix tree, we should
use it before looking the root up on disk.

Cc: <stable@vger.kernel.org> # 4.5
Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 187ee58c

fs/btrfs/disk-io.c

+2 −2
Original line number Diff line number Diff line
@@ -1624,7 +1624,7 @@ int btrfs_init_fs_root(struct btrfs_root *root) 
	return ret;

}



static struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,

struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,

					u64 root_id)

{

	struct btrfs_root *root;

fs/btrfs/disk-io.h

+2 −0
Original line number Diff line number Diff line
@@ -68,6 +68,8 @@ struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info, 
struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,

				      struct btrfs_key *location);

int btrfs_init_fs_root(struct btrfs_root *root);

struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,

					u64 root_id);

int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,

			 struct btrfs_root *root);

void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info);

fs/btrfs/root-tree.c

+18 −9
Original line number Diff line number Diff line
@@ -272,6 +272,23 @@ int btrfs_find_orphan_roots(struct btrfs_root *tree_root) 
		root_key.objectid = key.offset;

		key.offset++;



		/*

		 * The root might have been inserted already, as before we look

		 * for orphan roots, log replay might have happened, which

		 * triggers a transaction commit and qgroup accounting, which

		 * in turn reads and inserts fs roots while doing backref

		 * walking.

		 */

		root = btrfs_lookup_fs_root(tree_root->fs_info,

					    root_key.objectid);

		if (root) {

			WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,

					  &root->state));

			if (btrfs_root_refs(&root->root_item) == 0)

				btrfs_add_dead_root(root);

			continue;

		}



		root = btrfs_read_fs_root(tree_root, &root_key);

		err = PTR_ERR_OR_ZERO(root);

		if (err && err != -ENOENT) {
@@ -310,16 +327,8 @@ int btrfs_find_orphan_roots(struct btrfs_root *tree_root) 
		set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);



		err = btrfs_insert_fs_root(root->fs_info, root);

		/*

		 * The root might have been inserted already, as before we look

		 * for orphan roots, log replay might have happened, which

		 * triggers a transaction commit and qgroup accounting, which

		 * in turn reads and inserts fs roots while doing backref

		 * walking.

		 */

		if (err == -EEXIST)

			err = 0;

		if (err) {

			BUG_ON(err == -EEXIST);

			btrfs_free_fs_root(root);

			break;

		}