Commit 495ba899 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: fsck: Fix check_path_loop() + snapshots 



A path exists in a particular snapshot: we should do the pathwalk in the
snapshot ID of the inode we started from, _not_ change snapshot ID as we
walk inodes and dirents.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 583ba52a

fs/bcachefs/fsck.c

+26 −36
Original line number Diff line number Diff line
@@ -2689,19 +2689,13 @@ int bch2_check_subvolume_structure(struct bch_fs *c) 
	return ret;

}



struct pathbuf_entry {

	u64	inum;

	u32	snapshot;

};



typedef DARRAY(struct pathbuf_entry) pathbuf;



static int bch2_bi_depth_renumber_one(struct btree_trans *trans, struct pathbuf_entry *p,

static int bch2_bi_depth_renumber_one(struct btree_trans *trans,

				      u64 inum, u32 snapshot,

				      u32 new_depth)

{

	struct btree_iter iter;

	struct bkey_s_c k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_inodes,

					       SPOS(0, p->inum, p->snapshot), 0);

					       SPOS(0, inum, snapshot), 0);



	struct bch_inode_unpacked inode;

	int ret = bkey_err(k) ?:
@@ -2720,14 +2714,15 @@ static int bch2_bi_depth_renumber_one(struct btree_trans *trans, struct pathbuf_ 
	return ret;

}



static int bch2_bi_depth_renumber(struct btree_trans *trans, pathbuf *path, u32 new_bi_depth)

static int bch2_bi_depth_renumber(struct btree_trans *trans, darray_u64 *path,

				  u32 snapshot, u32 new_bi_depth)

{

	u32 restart_count = trans->restart_count;

	int ret = 0;



	darray_for_each_reverse(*path, i) {

		ret = nested_lockrestart_do(trans,

				bch2_bi_depth_renumber_one(trans, i, new_bi_depth));

				bch2_bi_depth_renumber_one(trans, *i, snapshot, new_bi_depth));

		bch_err_fn(trans->c, ret);

		if (ret)

			break;
@@ -2738,26 +2733,19 @@ static int bch2_bi_depth_renumber(struct btree_trans *trans, pathbuf *path, u32 
	return ret ?: trans_was_restarted(trans, restart_count);

}



static bool path_is_dup(pathbuf *p, u64 inum, u32 snapshot)

{

	darray_for_each(*p, i)

		if (i->inum	== inum &&

		    i->snapshot	== snapshot)

			return true;

	return false;

}



static int check_path_loop(struct btree_trans *trans, struct bkey_s_c inode_k)

{

	struct bch_fs *c = trans->c;

	struct btree_iter inode_iter = {};

	pathbuf path = {};

	darray_u64 path = {};

	struct printbuf buf = PRINTBUF;

	u32 snapshot = inode_k.k->p.snapshot;

	bool redo_bi_depth = false;

	u32 min_bi_depth = U32_MAX;

	int ret = 0;



	struct bpos start = inode_k.k->p;



	struct bch_inode_unpacked inode;

	ret = bch2_inode_unpack(inode_k, &inode);

	if (ret)
@@ -2766,9 +2754,9 @@ static int check_path_loop(struct btree_trans *trans, struct bkey_s_c inode_k) 
	while (!inode.bi_subvol) {

		struct btree_iter dirent_iter;

		struct bkey_s_c_dirent d;

		u32 parent_snapshot = snapshot;



		d = inode_get_dirent(trans, &dirent_iter, &inode, &parent_snapshot);

		d = dirent_get_by_pos(trans, &dirent_iter,

				      SPOS(inode.bi_dir, inode.bi_dir_offset, snapshot));

		ret = bkey_err(d.s_c);

		if (ret && !bch2_err_matches(ret, ENOENT))

			goto out;
@@ -2786,15 +2774,10 @@ static int check_path_loop(struct btree_trans *trans, struct bkey_s_c inode_k) 


		bch2_trans_iter_exit(trans, &dirent_iter);



		ret = darray_push(&path, ((struct pathbuf_entry) {

			.inum		= inode.bi_inum,

			.snapshot	= snapshot,

		}));

		ret = darray_push(&path, inode.bi_inum);

		if (ret)

			return ret;



		snapshot = parent_snapshot;



		bch2_trans_iter_exit(trans, &inode_iter);

		inode_k = bch2_bkey_get_iter(trans, &inode_iter, BTREE_ID_inodes,

					     SPOS(0, inode.bi_dir, snapshot), 0);
@@ -2816,15 +2799,22 @@ static int check_path_loop(struct btree_trans *trans, struct bkey_s_c inode_k) 
			break;



		inode = parent_inode;

		snapshot = inode_k.k->p.snapshot;

		redo_bi_depth = true;



		if (path_is_dup(&path, inode.bi_inum, snapshot)) {

		if (darray_find(path, inode.bi_inum)) {

			printbuf_reset(&buf);

			prt_printf(&buf, "directory structure loop:\n");

			darray_for_each_reverse(path, i)

				prt_printf(&buf, "%llu:%u ", i->inum, i->snapshot);

			prt_printf(&buf, "%llu:%u", inode.bi_inum, snapshot);

			prt_printf(&buf, "directory structure loop in snapshot %u: ",

				   snapshot);



			ret = bch2_inum_snapshot_to_path(trans, start.offset, start.snapshot, NULL, &buf);

			if (ret)

				goto out;



			if (c->opts.verbose) {

				prt_newline(&buf);

				darray_for_each(path, i)

					prt_printf(&buf, "%llu ", *i);

			}



			if (fsck_err(trans, dir_loop, "%s", buf.buf)) {

				ret = remove_backpointer(trans, &inode);
@@ -2844,7 +2834,7 @@ static int check_path_loop(struct btree_trans *trans, struct bkey_s_c inode_k) 
		min_bi_depth = 0;



	if (redo_bi_depth)

		ret = bch2_bi_depth_renumber(trans, &path, min_bi_depth);

		ret = bch2_bi_depth_renumber(trans, &path, snapshot, min_bi_depth);

out:

fsck_err:

	bch2_trans_iter_exit(trans, &inode_iter);