Author: trasz Date: Mon Aug 24 13:18:13 2015 New Revision: 287107 URL: https://svnweb.freebsd.org/changeset/base/287107
Log: Make vfs_unmountall() unmount /dev after /, not before. The only reason this didn't result in an unclean shutdown is that devfs ignores MNT_FORCE flag. Reviewed by: kib@ MFC after: 1 month Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D3467 Modified: head/sys/kern/vfs_mount.c head/sys/kern/vfs_mountroot.c head/sys/kern/vfs_subr.c head/sys/sys/vnode.h Modified: head/sys/kern/vfs_mount.c ============================================================================== --- head/sys/kern/vfs_mount.c Mon Aug 24 12:17:15 2015 (r287106) +++ head/sys/kern/vfs_mount.c Mon Aug 24 13:18:13 2015 (r287107) @@ -1359,6 +1359,8 @@ dounmount(struct mount *mp, int flags, s vput(coveredvp); } vfs_event_signal(NULL, VQ_UNMOUNT, 0); + if (mp == rootdevmp) + rootdevmp = NULL; vfs_mount_destroy(mp); return (0); } Modified: head/sys/kern/vfs_mountroot.c ============================================================================== --- head/sys/kern/vfs_mountroot.c Mon Aug 24 12:17:15 2015 (r287106) +++ head/sys/kern/vfs_mountroot.c Mon Aug 24 13:18:13 2015 (r287107) @@ -95,6 +95,11 @@ static struct mntarg *parse_mountroot_op */ struct vnode *rootvnode; +/* + * Mount of the system's /dev. + */ +struct mount *rootdevmp; + char *rootdevnames[2] = {NULL, NULL}; struct mtx root_holds_mtx; @@ -236,6 +241,7 @@ vfs_mountroot_devfs(struct thread *td, s mtx_unlock(&mountlist_mtx); *mpp = mp; + rootdevmp = mp; set_rootvnode(); error = kern_symlinkat(td, "/", AT_FDCWD, "dev", UIO_SYSSPACE); Modified: head/sys/kern/vfs_subr.c ============================================================================== --- head/sys/kern/vfs_subr.c Mon Aug 24 12:17:15 2015 (r287106) +++ head/sys/kern/vfs_subr.c Mon Aug 24 13:18:13 2015 (r287107) @@ -3543,6 +3543,21 @@ SYSCTL_PROC(_kern, KERN_VNODE, vnode, CT ""); #endif +static void +unmount_or_warn(struct mount *mp) +{ + int error; + + error = dounmount(mp, MNT_FORCE, curthread); + if (error != 0) { + printf("unmount of %s failed (", mp->mnt_stat.f_mntonname); + if (error == EBUSY) + printf("BUSY)\n"); + else + printf("%d)\n", error); + } +} + /* * Unmount all filesystems. The list is traversed in reverse order * of mounting to avoid dependencies. @@ -3550,42 +3565,28 @@ SYSCTL_PROC(_kern, KERN_VNODE, vnode, CT void vfs_unmountall(void) { - struct mount *mp; - struct thread *td; - int error; + struct mount *mp, *tmp; CTR1(KTR_VFS, "%s: unmounting all filesystems", __func__); - td = curthread; /* * Since this only runs when rebooting, it is not interlocked. */ - while(!TAILQ_EMPTY(&mountlist)) { - mp = TAILQ_LAST(&mountlist, mntlist); + TAILQ_FOREACH_REVERSE_SAFE(mp, &mountlist, mntlist, mnt_list, tmp) { vfs_ref(mp); - error = dounmount(mp, MNT_FORCE, td); - if (error != 0) { - TAILQ_REMOVE(&mountlist, mp, mnt_list); - /* - * XXX: Due to the way in which we mount the root - * file system off of devfs, devfs will generate a - * "busy" warning when we try to unmount it before - * the root. Don't print a warning as a result in - * order to avoid false positive errors that may - * cause needless upset. - */ - if (strcmp(mp->mnt_vfc->vfc_name, "devfs") != 0) { - printf("unmount of %s failed (", - mp->mnt_stat.f_mntonname); - if (error == EBUSY) - printf("BUSY)\n"); - else - printf("%d)\n", error); - } - } else { - /* The unmount has removed mp from the mountlist */ - } + + /* + * Forcibly unmounting "/dev" before "/" would prevent clean + * unmount of the latter. + */ + if (mp == rootdevmp) + continue; + + unmount_or_warn(mp); } + + if (rootdevmp != NULL) + unmount_or_warn(rootdevmp); } /* Modified: head/sys/sys/vnode.h ============================================================================== --- head/sys/sys/vnode.h Mon Aug 24 12:17:15 2015 (r287106) +++ head/sys/sys/vnode.h Mon Aug 24 13:18:13 2015 (r287107) @@ -420,6 +420,7 @@ extern int vttoif_tab[]; * Global vnode data. */ extern struct vnode *rootvnode; /* root (i.e. "/") vnode */ +extern struct mount *rootdevmp; /* "/dev" mount */ extern int async_io_version; /* 0 or POSIX version of AIO i'face */ extern int desiredvnodes; /* number of vnodes desired */ extern struct uma_zone *namei_zone; _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
