Add new unmount(2) flag, MNT_NONBUSY, to check whether there are

any open vnodes before proceeding. Make autounmound(8) use this flag.
Without it, even an unsuccessfull unmount causes filesystem flush,
which interferes with normal operation.

Reviewed by:	kib@
Approved by:	re (gjb@)
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D7047
This commit is contained in:
Edward Tomasz Napierala 2016-07-07 09:03:57 +00:00
parent af625dc998
commit debc480e03
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=302388
5 changed files with 68 additions and 12 deletions

View File

@ -28,7 +28,7 @@
.\" @(#)umount.8 8.2 (Berkeley) 5/8/95
.\" $FreeBSD$
.\"
.Dd June 17, 2015
.Dd July 7, 2016
.Dt UMOUNT 8
.Os
.Sh NAME
@ -36,12 +36,12 @@
.Nd unmount file systems
.Sh SYNOPSIS
.Nm
.Op Fl fv
.Op Fl fnv
.Ar special ... | node ... | fsid ...
.Nm
.Fl a | A
.Op Fl F Ar fstab
.Op Fl fv
.Op Fl fnv
.Op Fl h Ar host
.Op Fl t Ar type
.Sh DESCRIPTION
@ -94,6 +94,15 @@ option and, unless otherwise specified with the
option, will only unmount
.Tn NFS
file systems.
.It Fl n
Unless the
.Fl f
is used, the
.Nm
will not unmount an active file system.
It will, however, perform a flush.
This flag disables this behaviour, preventing the flush
if there are any files open.
.It Fl t Ar type
Is used to indicate the actions should only be taken on
file systems of the specified type.

View File

@ -91,7 +91,7 @@ main(int argc, char *argv[])
struct addrinfo hints;
all = errs = 0;
while ((ch = getopt(argc, argv, "AaF:fh:t:v")) != -1)
while ((ch = getopt(argc, argv, "AaF:fh:nt:v")) != -1)
switch (ch) {
case 'A':
all = 2;
@ -103,12 +103,15 @@ main(int argc, char *argv[])
setfstab(optarg);
break;
case 'f':
fflag = MNT_FORCE;
fflag |= MNT_FORCE;
break;
case 'h': /* -h implies -A. */
all = 2;
nfshost = optarg;
break;
case 'n':
fflag |= MNT_NONBUSY;
break;
case 't':
if (typelist != NULL)
err(1, "only one -t option may be specified");
@ -124,8 +127,11 @@ main(int argc, char *argv[])
argc -= optind;
argv += optind;
if ((fflag & MNT_FORCE) != 0 && (fflag & MNT_NONBUSY) != 0)
err(1, "-f and -n are mutually exclusive");
/* Start disks transferring immediately. */
if ((fflag & MNT_FORCE) == 0)
if ((fflag & (MNT_FORCE | MNT_NONBUSY)) == 0)
sync();
if ((argc == 0 && !all) || (argc != 0 && all))
@ -609,7 +615,7 @@ usage(void)
{
(void)fprintf(stderr, "%s\n%s\n",
"usage: umount [-fv] special ... | node ... | fsid ...",
" umount -a | -A [-F fstab] [-fv] [-h host] [-t type]");
"usage: umount [-fnv] special ... | node ... | fsid ...",
" umount -a | -A [-F fstab] [-fnv] [-h host] [-t type]");
exit(1);
}

View File

@ -1204,6 +1204,28 @@ sys_unmount(struct thread *td, struct unmount_args *uap)
return (error);
}
/*
* Return error if any of the vnodes, ignoring the root vnode
* and the syncer vnode, have non-zero usecount.
*/
static int
vfs_check_usecounts(struct mount *mp)
{
struct vnode *vp, *mvp;
MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
if ((vp->v_vflag & VV_ROOT) == 0 && vp->v_type != VNON &&
vp->v_usecount != 0) {
VI_UNLOCK(vp);
MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
return (EBUSY);
}
VI_UNLOCK(vp);
}
return (0);
}
/*
* Do the actual filesystem unmount.
*/
@ -1260,6 +1282,21 @@ dounmount(struct mount *mp, int flags, struct thread *td)
return (EBUSY);
}
mp->mnt_kern_flag |= MNTK_UNMOUNT | MNTK_NOINSMNTQ;
if (flags & MNT_NONBUSY) {
MNT_IUNLOCK(mp);
error = vfs_check_usecounts(mp);
MNT_ILOCK(mp);
if (error != 0) {
mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_NOINSMNTQ);
MNT_IUNLOCK(mp);
if (coveredvp != NULL) {
VOP_UNLOCK(coveredvp, 0);
vdrop(coveredvp);
}
vn_finished_write(mp);
return (error);
}
}
/* Allow filesystems to detect that a forced unmount is in progress. */
if (flags & MNT_FORCE) {
mp->mnt_kern_flag |= MNTK_UNMOUNTF;

View File

@ -312,17 +312,21 @@ void __mnt_vnode_markerfree_active(struct vnode **mvp, struct mount *);
* External filesystem command modifier flags.
* Unmount can use the MNT_FORCE flag.
* XXX: These are not STATES and really should be somewhere else.
* XXX: MNT_BYFSID collides with MNT_ACLS, but because MNT_ACLS is only used for
* mount(2) and MNT_BYFSID is only used for unmount(2) it's harmless.
* XXX: MNT_BYFSID and MNT_NONBUSY collide with MNT_ACLS and MNT_MULTILABEL,
* but because MNT_ACLS and MNT_MULTILABEL are only used for mount(2),
* and MNT_BYFSID and MNT_NONBUSY are only used for unmount(2),
* it's harmless.
*/
#define MNT_UPDATE 0x0000000000010000ULL /* not real mount, just update */
#define MNT_DELEXPORT 0x0000000000020000ULL /* delete export host lists */
#define MNT_RELOAD 0x0000000000040000ULL /* reload filesystem data */
#define MNT_FORCE 0x0000000000080000ULL /* force unmount or readonly */
#define MNT_SNAPSHOT 0x0000000001000000ULL /* snapshot the filesystem */
#define MNT_NONBUSY 0x0000000004000000ULL /* check vnode use counts. */
#define MNT_BYFSID 0x0000000008000000ULL /* specify filesystem by ID. */
#define MNT_CMDFLAGS (MNT_UPDATE | MNT_DELEXPORT | MNT_RELOAD | \
MNT_FORCE | MNT_SNAPSHOT | MNT_BYFSID)
MNT_FORCE | MNT_SNAPSHOT | MNT_NONBUSY | \
MNT_BYFSID)
/*
* Internal filesystem control flags stored in mnt_kern_flag.
*

View File

@ -161,7 +161,7 @@ unmount_by_fsid(const fsid_t fsid, const char *mountpoint)
if (ret < 0)
log_err(1, "asprintf");
error = unmount(fsid_str, MNT_BYFSID);
error = unmount(fsid_str, MNT_NONBUSY | MNT_BYFSID);
if (error != 0) {
if (errno == EBUSY) {
log_debugx("cannot unmount %s (%s): %s",