From 157f683c2aa9c15ebc06dd1deabeae149581d853 Mon Sep 17 00:00:00 2001 From: Tomohiro Kusumi Date: Fri, 28 Jun 2019 17:36:42 +0900 Subject: [PATCH] Don't use d_path() for automount mount point for chroot'd users Chroot'd users fail to automount snapshots due to realpath(3) failure in mount.zfs(8). Construct a mount point path from sb of the ctldir inode and dirent name, instead of from d_path(), so that chroot'd users don't get affected by their view of fs. Signed-off-by: Tomohiro Kusumi --- module/zfs/zfs_ctldir.c | 41 +++++++---------------------------------- 1 file changed, 7 insertions(+), 34 deletions(-) diff --git a/module/zfs/zfs_ctldir.c b/module/zfs/zfs_ctldir.c index c8071a7c215f..039a64ce10fb 100644 --- a/module/zfs/zfs_ctldir.c +++ b/module/zfs/zfs_ctldir.c @@ -703,37 +703,6 @@ zfsctl_snapshot_name(zfsvfs_t *zfsvfs, const char *snap_name, int len, return (0); } -/* - * Returns full path in full_path: "/pool/dataset/.zfs/snapshot/snap_name/" - */ -static int -zfsctl_snapshot_path(struct path *path, int len, char *full_path) -{ - char *path_buffer, *path_ptr; - int path_len, error = 0; - - path_buffer = kmem_alloc(len, KM_SLEEP); - - path_ptr = d_path(path, path_buffer, len); - if (IS_ERR(path_ptr)) { - error = -PTR_ERR(path_ptr); - goto out; - } - - path_len = path_buffer + len - 1 - path_ptr; - if (path_len > len) { - error = SET_ERROR(EFAULT); - goto out; - } - - memcpy(full_path, path_ptr, path_len); - full_path[path_len] = '\0'; -out: - kmem_free(path_buffer, len); - - return (error); -} - /* * Returns full path in full_path: "/pool/dataset/.zfs/snapshot/snap_name/" */ @@ -1077,9 +1046,13 @@ zfsctl_snapshot_mount(struct path *path, int flags) if (error) goto error; - error = zfsctl_snapshot_path(path, MAXPATHLEN, full_path); - if (error) - goto error; + /* + * Construct a mount point path from sb of the ctldir inode and dirent + * name, instead of from d_path(), so that chroot'd users don't fail on + * mount.zfs(8). + */ + snprintf(full_path, MAXPATHLEN, "%s/.zfs/snapshot/%s", + zfsvfs->z_vfs->vfs_mntpoint, dname(dentry)); /* * Multiple concurrent automounts of a snapshot are never allowed.