Merge tag 'pull-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull rename updates from Al Viro:
 "Fix directory locking scheme on rename

  This was broken in 6.5; we really can't lock two unrelated directories
  without holding ->s_vfs_rename_mutex first and in case of same-parent
  rename of a subdirectory 6.5 ends up doing just that"

* tag 'pull-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  rename(): avoid a deadlock in the case of parents having no common ancestor
  kill lock_two_inodes()
  rename(): fix the locking of subdirectories
  f2fs: Avoid reading renamed directory if parent does not change
  ext4: don't access the source subdirectory content on same-directory rename
  ext2: Avoid reading renamed directory if parent does not change
  udf_rename(): only access the child content on cross-directory rename
  ocfs2: Avoid touching renamed directory if parent does not change
  reiserfs: Avoid touching renamed directory if parent does not change

1 files changed, 13 insertions, 8 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index d252935f9c8a..467ba47a691c 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3591,10 +3591,14 @@ struct ext4_renament {
 	int dir_inlined;
 };
 
-static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
+static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent, bool is_cross)
 {
 	int retval;
 
+	ent->is_dir = true;
+	if (!is_cross)
+		return 0;
+
 	ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
 					      &retval, &ent->parent_de,
 					      &ent->dir_inlined);
@@ -3612,6 +3616,9 @@ static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
 {
 	int retval;
 
+	if (!ent->dir_bh)
+		return 0;
+
 	ent->parent_de->inode = cpu_to_le32(dir_ino);
 	BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
 	if (!ent->dir_inlined) {
@@ -3900,7 +3907,7 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 			if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
 				goto end_rename;
 		}
-		retval = ext4_rename_dir_prepare(handle, &old);
+		retval = ext4_rename_dir_prepare(handle, &old, new.dir != old.dir);
 		if (retval)
 			goto end_rename;
 	}
@@ -3964,7 +3971,7 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	}
 	inode_set_mtime_to_ts(old.dir, inode_set_ctime_current(old.dir));
 	ext4_update_dx_flag(old.dir);
-	if (old.dir_bh) {
+	if (old.is_dir) {
 		retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
 		if (retval)
 			goto end_rename;
@@ -3987,7 +3994,7 @@ static int ext4_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	if (unlikely(retval))
 		goto end_rename;
 
-	if (S_ISDIR(old.inode->i_mode)) {
+	if (old.is_dir) {
 		/*
 		 * We disable fast commits here that's because the
 		 * replay code is not yet capable of changing dot dot
@@ -4114,14 +4121,12 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
 		ext4_handle_sync(handle);
 
 	if (S_ISDIR(old.inode->i_mode)) {
-		old.is_dir = true;
-		retval = ext4_rename_dir_prepare(handle, &old);
+		retval = ext4_rename_dir_prepare(handle, &old, new.dir != old.dir);
 		if (retval)
 			goto end_rename;
 	}
 	if (S_ISDIR(new.inode->i_mode)) {
-		new.is_dir = true;
-		retval = ext4_rename_dir_prepare(handle, &new);
+		retval = ext4_rename_dir_prepare(handle, &new, new.dir != old.dir);
 		if (retval)
 			goto end_rename;
 	}