1 files changed, 37 insertions, 4 deletions

diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c
index aee40db7a0..4a29b0138d 100644
--- a/fs/nilfs2/dir.c
+++ b/fs/nilfs2/dir.c
@@ -135,6 +135,9 @@ static bool nilfs_check_folio(struct folio *folio, char *kaddr)
 			goto Enamelen;
 		if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
 			goto Espan;
+		if (unlikely(p->inode &&
+			     NILFS_PRIVATE_INODE(le64_to_cpu(p->inode))))
+			goto Einumber;
 	}
 	if (offs != limit)
 		goto Eend;
@@ -160,6 +163,9 @@ Enamelen:
 	goto bad_entry;
 Espan:
 	error = "directory entry across blocks";
+	goto bad_entry;
+Einumber:
+	error = "disallowed inode number";
 bad_entry:
 	nilfs_error(sb,
 		    "bad entry in directory #%lu: %s - offset=%lu, inode=%lu, rec_len=%zd, name_len=%d",
@@ -174,7 +180,6 @@ Eend:
 		    dir->i_ino, (folio->index << PAGE_SHIFT) + offs,
 		    (unsigned long)le64_to_cpu(p->inode));
 fail:
-	folio_set_error(folio);
 	return false;
 }
 
@@ -378,11 +383,39 @@ found:
 
 struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct folio **foliop)
 {
-	struct nilfs_dir_entry *de = nilfs_get_folio(dir, 0, foliop);
+	struct folio *folio;
+	struct nilfs_dir_entry *de, *next_de;
+	size_t limit;
+	char *msg;
 
+	de = nilfs_get_folio(dir, 0, &folio);
 	if (IS_ERR(de))
 		return NULL;
-	return nilfs_next_entry(de);
+
+	limit = nilfs_last_byte(dir, 0);  /* is a multiple of chunk size */
+	if (unlikely(!limit || le64_to_cpu(de->inode) != dir->i_ino ||
+		     !nilfs_match(1, ".", de))) {
+		msg = "missing '.'";
+		goto fail;
+	}
+
+	next_de = nilfs_next_entry(de);
+	/*
+	 * If "next_de" has not reached the end of the chunk, there is
+	 * at least one more record.  Check whether it matches "..".
+	 */
+	if (unlikely((char *)next_de == (char *)de + nilfs_chunk_size(dir) ||
+		     !nilfs_match(2, "..", next_de))) {
+		msg = "missing '..'";
+		goto fail;
+	}
+	*foliop = folio;
+	return next_de;
+
+fail:
+	nilfs_error(dir->i_sb, "directory #%lu %s", dir->i_ino, msg);
+	folio_release_kmap(folio, de);
+	return NULL;
 }
 
 ino_t nilfs_inode_by_name(struct inode *dir, const struct qstr *qstr)
@@ -608,7 +641,7 @@ int nilfs_empty_dir(struct inode *inode)
 
 		kaddr = nilfs_get_folio(inode, i, &folio);
 		if (IS_ERR(kaddr))
-			continue;
+			return 0;
 
 		de = (struct nilfs_dir_entry *)kaddr;
 		kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);