bcachefs: Check for casefolded dirents in non casefolded dirs

Check for mismatches between casefold dirents and casefold directories.

A mismatch will cause lookups to fail, as we'll be doing the lookup with
the casefolded name, which won't match the non-casefolded dirent, and
vice versa.

Reported-by: Christopher Snowhill <chris@kode54.net>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Author: Kent Overstreet

fs/bcachefs/fsck.c

@@ -2190,6 +2190,41 @@ static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
 
 	struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
 
+	/* check casefold */
+	if (fsck_err_on(d.v->d_casefold != !!hash_info->cf_encoding,
+			trans, dirent_casefold_mismatch,
+			"dirent casefold does not match dir casefold\n%s",
+			(printbuf_reset(&buf),
+			 bch2_bkey_val_to_text(&buf, c, k),
+			 buf.buf))) {
+		struct qstr name = bch2_dirent_get_name(d);
+		u32 subvol = d.v->d_type == DT_SUBVOL
+			? d.v->d_parent_subvol
+			: 0;
+		u64 target = d.v->d_type == DT_SUBVOL
+			? d.v->d_child_subvol
+			: d.v->d_inum;
+		u64 dir_offset;
+
+		ret =   bch2_hash_delete_at(trans,
+					    bch2_dirent_hash_desc, hash_info, iter,
+					    BTREE_UPDATE_internal_snapshot_node) ?:
+			bch2_dirent_create_snapshot(trans, subvol,
+						    d.k->p.inode, d.k->p.snapshot,
+						    hash_info,
+						    d.v->d_type,
+						    &name,
+						    target,
+						    &dir_offset,
+						    BTREE_ITER_with_updates|
+						    BTREE_UPDATE_internal_snapshot_node|
+						    STR_HASH_must_create) ?:
+			bch2_trans_commit(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc);
+
+		/* might need another check_dirents pass */
+		goto out;
+	}
+
 	if (d.v->d_type == DT_SUBVOL) {
 		ret = check_dirent_to_subvol(trans, iter, d);
 		if (ret)

fs/bcachefs/sb-errors_format.h

@@ -209,13 +209,15 @@ enum bch_fsck_flags {
 	x(subvol_to_missing_root,				188,	0)		\
 	x(subvol_root_wrong_bi_subvol,				189,	FSCK_AUTOFIX)	\
 	x(bkey_in_missing_snapshot,				190,	0)		\
+	x(bkey_in_deleted_snapshot,				315,	0)		\
 	x(inode_pos_inode_nonzero,				191,	0)		\
 	x(inode_pos_blockdev_range,				192,	0)		\
 	x(inode_alloc_cursor_inode_bad,				301,	0)		\
 	x(inode_unpack_error,					193,	0)		\
 	x(inode_str_hash_invalid,				194,	0)		\
 	x(inode_v3_fields_start_bad,				195,	0)		\
 	x(inode_snapshot_mismatch,				196,	0)		\
+	x(snapshot_key_missing_inode_snapshot,			314,	0)		\
 	x(inode_unlinked_but_clean,				197,	0)		\
 	x(inode_unlinked_but_nlink_nonzero,			198,	0)		\
 	x(inode_unlinked_and_not_open,				281,	0)		\
@@ -237,6 +239,8 @@ enum bch_fsck_flags {
 	x(inode_unreachable,					210,	FSCK_AUTOFIX)	\
 	x(inode_journal_seq_in_future,				299,	FSCK_AUTOFIX)	\
 	x(inode_i_sectors_underflow,				312,	FSCK_AUTOFIX)	\
+	x(inode_has_case_insensitive_not_set,			316,	FSCK_AUTOFIX)	\
+	x(inode_parent_has_case_insensitive_not_set,		317,	FSCK_AUTOFIX)	\
 	x(vfs_inode_i_blocks_underflow,				311,	FSCK_AUTOFIX)	\
 	x(vfs_inode_i_blocks_not_zero_at_truncate,		313,	FSCK_AUTOFIX)	\
 	x(deleted_inode_but_clean,				211,	FSCK_AUTOFIX)	\
@@ -262,6 +266,7 @@ enum bch_fsck_flags {
 	x(dirent_to_overwritten_inode,				302,	0)		\
 	x(dirent_to_missing_subvol,				230,	0)		\
 	x(dirent_to_itself,					231,	0)		\
+	x(dirent_casefold_mismatch,				318,	FSCK_AUTOFIX)	\
 	x(quota_type_invalid,					232,	0)		\
 	x(xattr_val_size_too_small,				233,	0)		\
 	x(xattr_val_size_too_big,				234,	0)		\
@@ -301,6 +306,7 @@ enum bch_fsck_flags {
 	x(btree_ptr_v2_written_0,				268,	0)		\
 	x(subvol_snapshot_bad,					269,	0)		\
 	x(subvol_inode_bad,					270,	0)		\
+	x(subvol_missing,					308,	FSCK_AUTOFIX)	\
 	x(alloc_key_stripe_sectors_wrong,			271,	FSCK_AUTOFIX)	\
 	x(accounting_mismatch,					272,	FSCK_AUTOFIX)	\
 	x(accounting_replicas_not_marked,			273,	0)		\
@@ -322,7 +328,7 @@ enum bch_fsck_flags {
 	x(dirent_stray_data_after_cf_name,			305,	0)		\
 	x(rebalance_work_incorrectly_set,			309,	FSCK_AUTOFIX)	\
 	x(rebalance_work_incorrectly_unset,			310,	FSCK_AUTOFIX)	\
-	x(MAX,							314,	0)
+	x(MAX,							319,	0)
 
 enum bch_sb_error_id {
 #define x(t, n, ...) BCH_FSCK_ERR_##t = n,