ovl: do not reconnect upper index records in ovl_indexdir_cleanup()

ovl_indexdir_cleanup() is called on mount of overayfs with nfs_export
feature to cleanup stale index records for lower and upper files that have
been deleted while overlayfs was offline.

This has the side effect (good or bad) of pre populating inode cache with
all the copied up upper inodes, while verifying the index entries.

For copied up directories, the upper file handles are decoded to conncted
upper dentries.  This has the even bigger side effect of reading the
content of all the parent upper directories which may take significantly
more time and IO than just reading the upper inodes.

Do not request connceted upper dentries for verifying upper directory index
entries, because we have no use for the connected dentry.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/export.c

@@ -463,7 +463,7 @@ static struct dentry *ovl_lookup_real_inode(struct super_block *sb,
 
 	/* Get connected upper overlay dir from index */
 	if (index) {
-		struct dentry *upper = ovl_index_upper(ofs, index);
+		struct dentry *upper = ovl_index_upper(ofs, index, true);
 
 		dput(index);
 		if (IS_ERR_OR_NULL(upper))
@@ -739,7 +739,7 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
 
 	/* Then try to get a connected upper dir by index */
 	if (index && d_is_dir(index)) {
-		struct dentry *upper = ovl_index_upper(ofs, index);
+		struct dentry *upper = ovl_index_upper(ofs, index, true);
 
 		err = PTR_ERR(upper);
 		if (IS_ERR_OR_NULL(upper))

fs/overlayfs/namei.c

@@ -487,7 +487,8 @@ int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
 }
 
 /* Get upper dentry from index */
-struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index)
+struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index,
+			       bool connected)
 {
 	struct ovl_fh *fh;
 	struct dentry *upper;
@@ -499,7 +500,7 @@ struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index)
 	if (IS_ERR_OR_NULL(fh))
 		return ERR_CAST(fh);
 
-	upper = ovl_decode_real_fh(ofs, fh, ovl_upper_mnt(ofs), true);
+	upper = ovl_decode_real_fh(ofs, fh, ovl_upper_mnt(ofs), connected);
 	kfree(fh);
 
 	if (IS_ERR_OR_NULL(upper))
@@ -572,7 +573,7 @@ int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index)
 	 * directly from the index dentry, but for dir index we first need to
 	 * decode the upper directory.
 	 */
-	upper = ovl_index_upper(ofs, index);
+	upper = ovl_index_upper(ofs, index, false);
 	if (IS_ERR_OR_NULL(upper)) {
 		err = PTR_ERR(upper);
 		/*

fs/overlayfs/overlayfs.h

@@ -525,7 +525,8 @@ int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
 		      enum ovl_xattr ox, struct dentry *real, bool is_upper,
 		      bool set);
-struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
+struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index,
+			       bool connected);
 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
 		       struct qstr *name);