ovl: persistent inode number for directories (b7a807dc) · Commits · 戴 / test

fs/overlayfs/dir.c

+33 −4

Original line number	Diff line number	Diff line
		@@ -150,12 +150,39 @@ static int ovl_dir_getattr(const struct path path, struct kstat stat,
		type = ovl_path_real(dentry, &realpath);
		old_cred = ovl_override_creds(dentry->d_sb);
		err = vfs_getattr(&realpath, stat, request_mask, flags);
		revert_creds(old_cred);
		if (err)
		return err;
		goto out;

		stat->dev = dentry->d_sb->s_dev;
		/*
		* When all layers are on the same fs, use the copy-up-origin st_ino,
		* which is persistent, unique and constant across copy up.
		*
		* Otherwise the pair {real st_ino; overlay st_dev} is not unique, so
		* use the non persistent overlay st_ino.
		*/
		if (ovl_same_sb(dentry->d_sb)) {
		if (OVL_TYPE_ORIGIN(type)) {
		struct kstat lowerstat;

		ovl_path_lower(dentry, &realpath);
		err = vfs_getattr(&realpath, &lowerstat,
		STATX_INO, flags);
		if (err)
		goto out;

		WARN_ON_ONCE(stat->dev != lowerstat.dev);
		stat->ino = lowerstat.ino;
		}
		} else {
		stat->ino = dentry->d_inode->i_ino;
		}

		/*
		* Always use the overlay st_dev for directories, so 'find -xdev' will
		* scan the entire overlay mount and won't cross the overlay mount
		* boundaries.
		*/
		stat->dev = dentry->d_sb->s_dev;

		/*
		* It's probably not worth it to count subdirs to get the
		@@ -164,8 +191,10 @@ static int ovl_dir_getattr(const struct path path, struct kstat stat,
		*/
		if (OVL_TYPE_MERGE(type))
		stat->nlink = 1;
		out:
		revert_creds(old_cred);

		return 0;
		return err;
		}

		/* Common operations required to be done after creation of file on upper */