diff options
Diffstat (limited to 'lib/libzfs/libzfs_mount.c')
| -rw-r--r-- | lib/libzfs/libzfs_mount.c | 110 |
1 files changed, 94 insertions, 16 deletions
diff --git a/lib/libzfs/libzfs_mount.c b/lib/libzfs/libzfs_mount.c index 9950bf967..75ce3676f 100644 --- a/lib/libzfs/libzfs_mount.c +++ b/lib/libzfs/libzfs_mount.c @@ -259,6 +259,82 @@ zfs_is_mountable(zfs_handle_t *zhp, char *buf, size_t buflen, } /* + * The filesystem is mounted by invoking the system mount utility rather + * than by the system call mount(2). This ensures that the /etc/mtab + * file is correctly locked for the update. Performing our own locking + * and /etc/mtab update requires making an unsafe assumption about how + * the mount utility performs its locking. Unfortunately, this also means + * in the case of a mount failure we do not have the exact errno. We must + * make due with return value from the mount process. + * + * In the long term a shared library called libmount is under development + * which provides a common API to address the locking and errno issues. + * Once the standard mount utility has been updated to use this library + * we can add an autoconf check to conditionally use it. + * + * http://www.kernel.org/pub/linux/utils/util-linux/libmount-docs/index.html + */ + +static int +do_mount(const char *src, const char *mntpt, char *opts) +{ + char *argv[8] = { + "/bin/mount", + "-t", MNTTYPE_ZFS, + "-o", opts, + (char *)src, + (char *)mntpt, + (char *)NULL }; + int rc; + + /* Return only the most critical mount error */ + rc = libzfs_run_process(argv[0], argv); + if (rc) { + if (rc & MOUNT_FILEIO) + return EIO; + if (rc & MOUNT_USER) + return EINTR; + if (rc & MOUNT_SOFTWARE) + return EPIPE; + if (rc & MOUNT_SYSERR) + return EAGAIN; + if (rc & MOUNT_USAGE) + return EINVAL; + + return ENXIO; /* Generic error */ + } + + return 0; +} + +static int +do_unmount(const char *mntpt, int flags) +{ + char force_opt[] = "-f"; + char lazy_opt[] = "-l"; + char *argv[7] = { + "/bin/umount", + "-t", MNTTYPE_ZFS, + NULL, NULL, NULL, NULL }; + int rc, count = 3; + + if (flags & MS_FORCE) { + argv[count] = force_opt; + count++; + } + + if (flags & MS_DETACH) { + argv[count] = lazy_opt; + count++; + } + + argv[count] = (char *)mntpt; + rc = libzfs_run_process(argv[0], argv); + + return (rc ? EINVAL : 0); +} + +/* * Mount the given filesystem. */ int @@ -268,9 +344,10 @@ zfs_mount(zfs_handle_t *zhp, const char *options, int flags) char mountpoint[ZFS_MAXPROPLEN]; char mntopts[MNT_LINE_MAX]; libzfs_handle_t *hdl = zhp->zfs_hdl; + int rc; if (options == NULL) - mntopts[0] = '\0'; + (void) strlcpy(mntopts, MNTOPT_DEFAULTS, sizeof (mntopts)); else (void) strlcpy(mntopts, options, sizeof (mntopts)); @@ -278,7 +355,12 @@ zfs_mount(zfs_handle_t *zhp, const char *options, int flags) * If the pool is imported read-only then all mounts must be read-only */ if (zpool_get_prop_int(zhp->zpool_hdl, ZPOOL_PROP_READONLY, NULL)) - flags |= MS_RDONLY; + (void) strlcat(mntopts, "," MNTOPT_RO, sizeof (mntopts)); + + /* + * Append zfsutil option so the mount helper allow the mount + */ + strlcat(mntopts, "," MNTOPT_ZFSUTIL, sizeof (mntopts)); #ifdef HAVE_LIBSELINUX if (is_selinux_enabled()) @@ -302,12 +384,9 @@ zfs_mount(zfs_handle_t *zhp, const char *options, int flags) /* * Determine if the mountpoint is empty. If so, refuse to perform the - * mount. We don't perform this check if MS_OVERLAY is specified, which - * would defeat the point. We also avoid this check if 'remount' is - * specified. + * mount. We don't perform this check if 'remount' is specified. */ - if ((flags & MS_OVERLAY) == 0 && - strstr(mntopts, MNTOPT_REMOUNT) == NULL && + if (strstr(mntopts, MNTOPT_REMOUNT) == NULL && !dir_is_empty(mountpoint)) { zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "directory is not empty")); @@ -316,20 +395,20 @@ zfs_mount(zfs_handle_t *zhp, const char *options, int flags) } /* perform the mount */ - if (mount(zfs_get_name(zhp), mountpoint, MS_OPTIONSTR | flags, - MNTTYPE_ZFS, NULL, 0, mntopts, sizeof (mntopts)) != 0) { + rc = do_mount(zfs_get_name(zhp), mountpoint, mntopts); + if (rc) { /* * Generic errors are nasty, but there are just way too many * from mount(), and they're well-understood. We pick a few * common ones to improve upon. */ - if (errno == EBUSY) { + if (rc == EBUSY) { zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "mountpoint or dataset is busy")); - } else if (errno == EPERM) { + } else if (rc == EPERM) { zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "Insufficient privileges")); - } else if (errno == ENOTSUP) { + } else if (rc == ENOTSUP) { char buf[256]; int spa_version; @@ -342,7 +421,7 @@ zfs_mount(zfs_handle_t *zhp, const char *options, int flags) ZFS_PROP_VERSION), spa_version); zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, buf)); } else { - zfs_error_aux(hdl, strerror(errno)); + zfs_error_aux(hdl, strerror(rc)); } return (zfs_error_fmt(hdl, EZFS_MOUNTFAILED, dgettext(TEXT_DOMAIN, "cannot mount '%s'"), @@ -350,8 +429,7 @@ zfs_mount(zfs_handle_t *zhp, const char *options, int flags) } /* add the mounted entry into our cache */ - libzfs_mnttab_add(hdl, zfs_get_name(zhp), mountpoint, - mntopts); + libzfs_mnttab_add(hdl, zfs_get_name(zhp), mountpoint, mntopts); return (0); } @@ -361,7 +439,7 @@ zfs_mount(zfs_handle_t *zhp, const char *options, int flags) static int unmount_one(libzfs_handle_t *hdl, const char *mountpoint, int flags) { - if (umount2(mountpoint, flags) != 0) { + if (do_unmount(mountpoint, flags) != 0) { zfs_error_aux(hdl, strerror(errno)); return (zfs_error_fmt(hdl, EZFS_UMOUNTFAILED, dgettext(TEXT_DOMAIN, "cannot unmount '%s'"), |