Commit a6508079 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: dirent_points_to_inode() now warns on mismatch 



if an inode backpointer points to a dirent that doesn't point back,
that's an error we should warn about.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent e057a290

fs/bcachefs/fsck.c

+56 −28
Original line number Diff line number Diff line
@@ -21,6 +21,49 @@ 
#include <linux/bsearch.h>

#include <linux/dcache.h> /* struct qstr */



static bool inode_points_to_dirent(struct bch_inode_unpacked *inode,

				   struct bkey_s_c_dirent d)

{

	return  inode->bi_dir		== d.k->p.inode &&

		inode->bi_dir_offset	== d.k->p.offset;

}



static bool dirent_points_to_inode_nowarn(struct bkey_s_c_dirent d,

				   struct bch_inode_unpacked *inode)

{

	if (d.v->d_type == DT_SUBVOL

	    ? le32_to_cpu(d.v->d_child_subvol)	== inode->bi_subvol

	    : le64_to_cpu(d.v->d_inum)		== inode->bi_inum)

		return 0;

	return -BCH_ERR_ENOENT_dirent_doesnt_match_inode;

}



static void dirent_inode_mismatch_msg(struct printbuf *out,

				      struct bch_fs *c,

				      struct bkey_s_c_dirent dirent,

				      struct bch_inode_unpacked *inode)

{

	prt_str(out, "inode points to dirent that does not point back:");

	prt_newline(out);

	bch2_bkey_val_to_text(out, c, dirent.s_c);

	prt_newline(out);

	bch2_inode_unpacked_to_text(out, inode);

}



static int dirent_points_to_inode(struct bch_fs *c,

				  struct bkey_s_c_dirent dirent,

				  struct bch_inode_unpacked *inode)

{

	int ret = dirent_points_to_inode_nowarn(dirent, inode);

	if (ret) {

		struct printbuf buf = PRINTBUF;

		dirent_inode_mismatch_msg(&buf, c, dirent, inode);

		bch_warn(c, "%s", buf.buf);

		printbuf_exit(&buf);

	}

	return ret;

}



/*

 * XXX: this is handling transaction restarts without returning

 * -BCH_ERR_transaction_restart_nested, this is not how we do things anymore:
@@ -371,6 +414,7 @@ static int reattach_subvol(struct btree_trans *trans, struct bkey_s_c_subvolume 
		return ret;



	ret = remove_backpointer(trans, &inode);

	if (!bch2_err_matches(ret, ENOENT))

		bch_err_msg(c, ret, "removing dirent");

	if (ret)

		return ret;
@@ -900,21 +944,6 @@ static struct bkey_s_c_dirent inode_get_dirent(struct btree_trans *trans, 
	return dirent_get_by_pos(trans, iter, SPOS(inode->bi_dir, inode->bi_dir_offset, *snapshot));

}



static bool inode_points_to_dirent(struct bch_inode_unpacked *inode,

				   struct bkey_s_c_dirent d)

{

	return  inode->bi_dir		== d.k->p.inode &&

		inode->bi_dir_offset	== d.k->p.offset;

}



static bool dirent_points_to_inode(struct bkey_s_c_dirent d,

				   struct bch_inode_unpacked *inode)

{

	return d.v->d_type == DT_SUBVOL

		? le32_to_cpu(d.v->d_child_subvol)	== inode->bi_subvol

		: le64_to_cpu(d.v->d_inum)		== inode->bi_inum;

}



static int check_inode_deleted_list(struct btree_trans *trans, struct bpos p)

{

	struct btree_iter iter;
@@ -924,13 +953,14 @@ static int check_inode_deleted_list(struct btree_trans *trans, struct bpos p) 
	return ret;

}



static int check_inode_dirent_inode(struct btree_trans *trans, struct bkey_s_c inode_k,

static int check_inode_dirent_inode(struct btree_trans *trans,

				    struct bch_inode_unpacked *inode,

				    u32 inode_snapshot, bool *write_inode)

				    bool *write_inode)

{

	struct bch_fs *c = trans->c;

	struct printbuf buf = PRINTBUF;



	u32 inode_snapshot = inode->bi_snapshot;

	struct btree_iter dirent_iter = {};

	struct bkey_s_c_dirent d = inode_get_dirent(trans, &dirent_iter, inode, &inode_snapshot);

	int ret = bkey_err(d);
@@ -940,13 +970,13 @@ static int check_inode_dirent_inode(struct btree_trans *trans, struct bkey_s_c i 
	if (fsck_err_on(ret,

			trans, inode_points_to_missing_dirent,

			"inode points to missing dirent\n%s",

			(bch2_bkey_val_to_text(&buf, c, inode_k), buf.buf)) ||

	    fsck_err_on(!ret && !dirent_points_to_inode(d, inode),

			(bch2_inode_unpacked_to_text(&buf, inode), buf.buf)) ||

	    fsck_err_on(!ret && dirent_points_to_inode_nowarn(d, inode),

			trans, inode_points_to_wrong_dirent,

			"inode points to dirent that does not point back:\n%s",

			(bch2_bkey_val_to_text(&buf, c, inode_k),

			 prt_newline(&buf),

			 bch2_bkey_val_to_text(&buf, c, d.s_c), buf.buf))) {

			"%s",

			(printbuf_reset(&buf),

			 dirent_inode_mismatch_msg(&buf, c, d, inode),

			 buf.buf))) {

		/*

		 * We just clear the backpointer fields for now. If we find a

		 * dirent that points to this inode in check_dirents(), we'll
@@ -1145,7 +1175,7 @@ static int check_inode(struct btree_trans *trans, 
	}



	if (u.bi_dir || u.bi_dir_offset) {

		ret = check_inode_dirent_inode(trans, k, &u, k.k->p.snapshot, &do_update);

		ret = check_inode_dirent_inode(trans, &u, &do_update);

		if (ret)

			goto err;

	}
@@ -2474,10 +2504,8 @@ static int check_path(struct btree_trans *trans, pathbuf *p, struct bkey_s_c ino 
		if (ret && !bch2_err_matches(ret, ENOENT))

			break;



		if (!ret && !dirent_points_to_inode(d, &inode)) {

		if (!ret && (ret = dirent_points_to_inode(c, d, &inode)))

			bch2_trans_iter_exit(trans, &dirent_iter);

			ret = -BCH_ERR_ENOENT_dirent_doesnt_match_inode;

		}



		if (bch2_err_matches(ret, ENOENT)) {

			ret = 0;