Discussed with: kib
Tested by: pho
Modified:
head/sys/geom/journal/g_journal.c
head/sys/gnu/fs/ext2fs/ext2_vfsops.c
head/sys/kern/vfs_lookup.c
head/sys/kern/vfs_mount.c
head/sys/kern/vfs_subr.c
head/sys/kern/vfs_syscalls.c
head/sys/kern/vfs_vnops.c
head/sys/nfsclient/nfs_socket.c
head/sys/nfsclient/nfs_vfsops.c
head/sys/sys/mount.h
head/sys/ufs/ffs/ffs_softdep.c
head/sys/ufs/ufs/ufs_vfsops.c
Modified: head/sys/geom/journal/g_journal.c
==============================================================================
--- head/sys/geom/journal/g_journal.c Sun Nov 2 06:40:33 2008
(r184553)
+++ head/sys/geom/journal/g_journal.c Sun Nov 2 10:15:42 2008
(r184554)
@@ -2879,7 +2879,7 @@ g_journal_do_switch(struct g_class *clas
desc = g_journal_find_desc(mp->mnt_stat.f_fstypename);
if (desc == NULL)
continue;
- if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx))
+ if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK))
continue;
/* mtx_unlock(&mountlist_mtx) was done inside vfs_busy() */
Modified: head/sys/gnu/fs/ext2fs/ext2_vfsops.c
==============================================================================
--- head/sys/gnu/fs/ext2fs/ext2_vfsops.c Sun Nov 2 06:40:33 2008
(r184553)
+++ head/sys/gnu/fs/ext2fs/ext2_vfsops.c Sun Nov 2 10:15:42 2008
(r184554)
@@ -171,7 +171,7 @@ ext2_mount(mp, td)
flags = WRITECLOSE;
if (mp->mnt_flag & MNT_FORCE)
flags |= FORCECLOSE;
- if (vfs_busy(mp, LK_NOWAIT, 0))
+ if (vfs_busy(mp, MBF_NOWAIT))
return (EBUSY);
error = ext2_flushfiles(mp, flags, td);
vfs_unbusy(mp);
Modified: head/sys/kern/vfs_lookup.c
==============================================================================
--- head/sys/kern/vfs_lookup.c Sun Nov 2 06:40:33 2008 (r184553)
+++ head/sys/kern/vfs_lookup.c Sun Nov 2 10:15:42 2008 (r184554)
@@ -684,7 +684,7 @@ unionlookup:
*/
while (dp->v_type == VDIR && (mp = dp->v_mountedhere) &&
(cnp->cn_flags & NOCROSSMOUNT) == 0) {
- if (vfs_busy(mp, 0, 0))
+ if (vfs_busy(mp, 0))
continue;
vput(dp);
VFS_UNLOCK_GIANT(vfslocked);
Modified: head/sys/kern/vfs_mount.c
==============================================================================
--- head/sys/kern/vfs_mount.c Sun Nov 2 06:40:33 2008 (r184553)
+++ head/sys/kern/vfs_mount.c Sun Nov 2 10:15:42 2008 (r184554)
@@ -450,7 +450,6 @@ mount_init(void *mem, int size, int flag
mp = (struct mount *)mem;
mtx_init(&mp->mnt_mtx, "struct mount mtx", NULL, MTX_DEF);
- lockinit(&mp->mnt_lock, PVFS, "vfslock", 0, 0);
lockinit(&mp->mnt_explock, PVFS, "explock", 0, 0);
return (0);
}
@@ -462,7 +461,6 @@ mount_fini(void *mem, int size)
mp = (struct mount *)mem;
lockdestroy(&mp->mnt_explock);
- lockdestroy(&mp->mnt_lock);
mtx_destroy(&mp->mnt_mtx);
}
@@ -481,7 +479,7 @@ vfs_mount_alloc(struct vnode *vp, struct
TAILQ_INIT(&mp->mnt_nvnodelist);
mp->mnt_nvnodelistsize = 0;
mp->mnt_ref = 0;
- (void) vfs_busy(mp, LK_NOWAIT, 0);
+ (void) vfs_busy(mp, MBF_NOWAIT);
mp->mnt_op = vfsp->vfc_vfsops;
mp->mnt_vfc = vfsp;
vfsp->vfc_refcount++; /* XXX Unlocked */
@@ -507,19 +505,10 @@ vfs_mount_alloc(struct vnode *vp, struct
void
vfs_mount_destroy(struct mount *mp)
{
- int i;
MNT_ILOCK(mp);
- for (i = 0; mp->mnt_ref && i < 3; i++)
- msleep(mp, MNT_MTX(mp), PVFS, "mntref", hz);
- /*
- * This will always cause a 3 second delay in rebooting due to
- * refs on the root mountpoint that never go away. Most of these
- * are held by init which never exits.
- */
- if (i == 3 && (!rebooting || bootverbose))
- printf("Mount point %s had %d dangling refs\n",
- mp->mnt_stat.f_mntonname, mp->mnt_ref);
+ while (mp->mnt_ref)
+ msleep(mp, MNT_MTX(mp), PVFS, "mntref", 0);
if (mp->mnt_holdcnt != 0) {
printf("Waiting for mount point to be unheld\n");
while (mp->mnt_holdcnt != 0) {
@@ -928,7 +917,7 @@ vfs_domount(
vput(vp);
return (error);
}
- if (vfs_busy(mp, LK_NOWAIT, 0)) {
+ if (vfs_busy(mp, MBF_NOWAIT)) {
vput(vp);
return (EBUSY);
}
@@ -1245,19 +1234,31 @@ dounmount(mp, flags, td)
/* Allow filesystems to detect that a forced unmount is in progress. */
if (flags & MNT_FORCE)
mp->mnt_kern_flag |= MNTK_UNMOUNTF;
- error = lockmgr(&mp->mnt_lock, LK_DRAIN | LK_INTERLOCK |
- ((flags & MNT_FORCE) ? 0 : LK_NOWAIT), MNT_MTX(mp));
- if (error) {
- MNT_ILOCK(mp);
- mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_NOINSMNTQ |
- MNTK_UNMOUNTF);
- if (mp->mnt_kern_flag & MNTK_MWAIT)
- wakeup(mp);
- MNT_IUNLOCK(mp);
- if (coveredvp)
- VOP_UNLOCK(coveredvp, 0);
- return (error);
+ error = 0;
+ if (mp->mnt_lockref) {
+ if (flags & MNT_FORCE) {
+ mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_NOINSMNTQ |
+ MNTK_UNMOUNTF);
+ if (mp->mnt_kern_flag & MNTK_MWAIT) {
+ mp->mnt_kern_flag &= ~MNTK_MWAIT;
+ wakeup(mp);
+ }
+ MNT_IUNLOCK(mp);
+ if (coveredvp)
+ VOP_UNLOCK(coveredvp, 0);
+ return (EBUSY);
+ }
+ mp->mnt_kern_flag |= MNTK_DRAINING;
+ error = msleep(&mp->mnt_lockref, MNT_MTX(mp), PVFS,
+ "mount drain", 0);
}
+ MNT_IUNLOCK(mp);
+ KASSERT(mp->mnt_lockref == 0,
+ ("%s: invalid lock refcount in the drain path @ %s:%d",
+ __func__, __FILE__, __LINE__));
+ KASSERT(error == 0,
+ ("%s: invalid return value for msleep in the drain path @ %s:%d",
+ __func__, __FILE__, __LINE__));
vn_start_write(NULL, &mp, V_WAIT);
if (mp->mnt_flag & MNT_EXPUBLIC)
@@ -1321,9 +1322,10 @@ dounmount(mp, flags, td)
mp->mnt_flag |= async_flag;
if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
mp->mnt_kern_flag |= MNTK_ASYNC;
- lockmgr(&mp->mnt_lock, LK_RELEASE, NULL);
- if (mp->mnt_kern_flag & MNTK_MWAIT)
+ if (mp->mnt_kern_flag & MNTK_MWAIT) {
+ mp->mnt_kern_flag &= ~MNTK_MWAIT;
wakeup(mp);
+ }
MNT_IUNLOCK(mp);
if (coveredvp)
VOP_UNLOCK(coveredvp, 0);
@@ -1337,7 +1339,6 @@ dounmount(mp, flags, td)
vput(coveredvp);
}
vfs_event_signal(NULL, VQ_UNMOUNT, 0);
- lockmgr(&mp->mnt_lock, LK_RELEASE, NULL);
vfs_mount_destroy(mp);
return (0);
}
@@ -2070,7 +2071,6 @@ __mnt_vnode_first(struct vnode **mvp, st
wakeup(&mp->mnt_holdcnt);
return (NULL);
}
- mp->mnt_markercnt++;
(*mvp)->v_mount = mp;
TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes);
return (vp);
@@ -2093,7 +2093,6 @@ __mnt_vnode_markerfree(struct vnode **mv
MNT_ILOCK(mp);
*mvp = NULL;
- mp->mnt_markercnt--;
mp->mnt_holdcnt--;
if (mp->mnt_holdcnt == 0 && mp->mnt_holdcntwaiters != 0)
wakeup(&mp->mnt_holdcnt);
Modified: head/sys/kern/vfs_subr.c
==============================================================================
--- head/sys/kern/vfs_subr.c Sun Nov 2 06:40:33 2008 (r184553)
+++ head/sys/kern/vfs_subr.c Sun Nov 2 10:15:42 2008 (r184554)
@@ -335,42 +335,36 @@ SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST,
/*
* Mark a mount point as busy. Used to synchronize access and to delay
- * unmounting. Interlock is not released on failure.
+ * unmounting. Eventually, mountlist_mtx is not released on failure.
*/
int
-vfs_busy(struct mount *mp, int flags, struct mtx *interlkp)
+vfs_busy(struct mount *mp, int flags)
{
- int lkflags;
+
+ MPASS((flags & ~MBF_MASK) == 0);
MNT_ILOCK(mp);
MNT_REF(mp);
if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
- if (flags & LK_NOWAIT) {
+ if (flags & MBF_NOWAIT) {
MNT_REL(mp);
MNT_IUNLOCK(mp);
return (ENOENT);
}
- if (interlkp)
- mtx_unlock(interlkp);
+ if (flags & MBF_MNTLSTLOCK)
+ mtx_unlock(&mountlist_mtx);
mp->mnt_kern_flag |= MNTK_MWAIT;
- /*
- * Since all busy locks are shared except the exclusive
- * lock granted when unmounting, the only place that a
- * wakeup needs to be done is at the release of the
- * exclusive lock at the end of dounmount.
- */
msleep(mp, MNT_MTX(mp), PVFS, "vfs_busy", 0);
MNT_REL(mp);
MNT_IUNLOCK(mp);
- if (interlkp)
- mtx_lock(interlkp);
+ if (flags & MBF_MNTLSTLOCK)
+ mtx_lock(&mountlist_mtx);
return (ENOENT);
}
- if (interlkp)
- mtx_unlock(interlkp);
- lkflags = LK_SHARED | LK_INTERLOCK | LK_NOWAIT;
- if (lockmgr(&mp->mnt_lock, lkflags, MNT_MTX(mp)))
- panic("vfs_busy: unexpected lock failure");
+ if (flags & MBF_MNTLSTLOCK)
+ mtx_unlock(&mountlist_mtx);
+ mp->mnt_lockref++;
+ MNT_IUNLOCK(mp);
return (0);
}
@@ -381,8 +375,15 @@ void
vfs_unbusy(struct mount *mp)
{
- lockmgr(&mp->mnt_lock, LK_RELEASE, NULL);
- vfs_rel(mp);
+ MNT_ILOCK(mp);
+ MNT_REL(mp);
+ mp->mnt_lockref--;
+ if (mp->mnt_lockref == 0 && (mp->mnt_kern_flag & MNTK_DRAINING) != 0) {
+ MPASS(mp->mnt_kern_flag & MNTK_UNMOUNT);
+ mp->mnt_kern_flag &= ~MNTK_DRAINING;
+ wakeup(&mp->mnt_lockref);
+ }
+ MNT_IUNLOCK(mp);
}
/*
@@ -747,7 +748,7 @@ vnlru_proc(void)
mtx_lock(&mountlist_mtx);
for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
int vfsunlocked;
- if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx)) {
+ if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK)) {
nmp = TAILQ_NEXT(mp, mnt_list);
continue;
}
@@ -2837,7 +2838,6 @@ DB_SHOW_COMMAND(mount, db_show_mount)
db_printf(" mnt_maxsymlinklen = %d\n", mp->mnt_maxsymlinklen);
db_printf(" mnt_iosize_max = %d\n", mp->mnt_iosize_max);
db_printf(" mnt_hashseed = %u\n", mp->mnt_hashseed);
- db_printf(" mnt_markercnt = %d\n", mp->mnt_markercnt);
db_printf(" mnt_holdcnt = %d\n", mp->mnt_holdcnt);
db_printf(" mnt_holdcntwaiters = %d\n", mp->mnt_holdcntwaiters);
db_printf(" mnt_secondary_writes = %d\n", mp->mnt_secondary_writes);
@@ -2999,7 +2999,7 @@ sysctl_vnode(SYSCTL_HANDLER_ARGS)
n = 0;
mtx_lock(&mountlist_mtx);
TAILQ_FOREACH(mp, &mountlist, mnt_list) {
- if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx))
+ if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK))
continue;
MNT_ILOCK(mp);
TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
@@ -3361,7 +3361,7 @@ sync_fsync(struct vop_fsync_args *ap)
* not already on the sync list.
*/
mtx_lock(&mountlist_mtx);
- if (vfs_busy(mp, LK_EXCLUSIVE | LK_NOWAIT, &mountlist_mtx) != 0) {
+ if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK) != 0) {
mtx_unlock(&mountlist_mtx);
return (0);
}
Modified: head/sys/kern/vfs_syscalls.c
==============================================================================
--- head/sys/kern/vfs_syscalls.c Sun Nov 2 06:40:33 2008
(r184553)
+++ head/sys/kern/vfs_syscalls.c Sun Nov 2 10:15:42 2008
(r184554)
@@ -124,7 +124,7 @@ sync(td, uap)
mtx_lock(&mountlist_mtx);
for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
- if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx)) {
+ if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK)) {
nmp = TAILQ_NEXT(mp, mnt_list);
continue;
}
@@ -197,7 +197,7 @@ quotactl(td, uap)
vfslocked = NDHASGIANT(&nd);
NDFREE(&nd, NDF_ONLY_PNBUF);
mp = nd.ni_vp->v_mount;
- if ((error = vfs_busy(mp, 0, NULL))) {
+ if ((error = vfs_busy(mp, 0))) {
vrele(nd.ni_vp);
VFS_UNLOCK_GIANT(vfslocked);
return (error);
@@ -479,7 +479,7 @@ kern_getfsstat(struct thread *td, struct
continue;
}
#endif
- if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx)) {
+ if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK)) {
nmp = TAILQ_NEXT(mp, mnt_list);
continue;
}
@@ -741,7 +741,7 @@ fchdir(td, uap)
error = change_dir(vp, td);
while (!error && (mp = vp->v_mountedhere) != NULL) {
int tvfslocked;
- if (vfs_busy(mp, 0, 0))
+ if (vfs_busy(mp, 0))
continue;
tvfslocked = VFS_LOCK_GIANT(mp);
error = VFS_ROOT(mp, LK_EXCLUSIVE, &tdp, td);
Modified: head/sys/kern/vfs_vnops.c
==============================================================================
--- head/sys/kern/vfs_vnops.c Sun Nov 2 06:40:33 2008 (r184553)
+++ head/sys/kern/vfs_vnops.c Sun Nov 2 10:15:42 2008 (r184554)
@@ -957,9 +957,18 @@ vn_start_write(vp, mpp, flags)
}
if ((mp = *mpp) == NULL)
return (0);
+
+ /*
+ * VOP_GETWRITEMOUNT() returns with the mp refcount held through
+ * a vfs_ref().
+ * As long as a vnode is not provided we need to acquire a
+ * refcount for the provided mountpoint too, in order to
+ * emulate a vfs_ref().
+ */
MNT_ILOCK(mp);
if (vp == NULL)
MNT_REF(mp);
+
/*
* Check on status of suspension.
*/
@@ -1021,6 +1030,14 @@ vn_start_secondary_write(vp, mpp, flags)
*/
if ((mp = *mpp) == NULL)
return (0);
+
+ /*
+ * VOP_GETWRITEMOUNT() returns with the mp refcount held through
+ * a vfs_ref().
+ * As long as a vnode is not provided we need to acquire a
+ * refcount for the provided mountpoint too, in order to
+ * emulate a vfs_ref().
+ */
MNT_ILOCK(mp);
if (vp == NULL)
MNT_REF(mp);
Modified: head/sys/nfsclient/nfs_socket.c
==============================================================================
--- head/sys/nfsclient/nfs_socket.c Sun Nov 2 06:40:33 2008
(r184553)
+++ head/sys/nfsclient/nfs_socket.c Sun Nov 2 10:15:42 2008
(r184554)
@@ -1429,8 +1429,8 @@ nfs_timer(void *arg)
/*
* Terminate request if force-unmount in progress.
* Note that NFS could have vfs_busy'ed the mount,
- * causing the unmount to wait for the mnt_lock, making
- * this bit of logic necessary.
+ * causing the unmount to wait and making this bit
+ * of logic necessary.
*/
if (rep->r_nmp->nm_mountp->mnt_kern_flag &
MNTK_UNMOUNTF) {
nfs_softterm(rep);
Modified: head/sys/nfsclient/nfs_vfsops.c
==============================================================================
--- head/sys/nfsclient/nfs_vfsops.c Sun Nov 2 06:40:33 2008
(r184553)
+++ head/sys/nfsclient/nfs_vfsops.c Sun Nov 2 10:15:42 2008
(r184554)
@@ -258,7 +258,7 @@ nfs_statfs(struct mount *mp, struct stat
#ifndef nolint
sfp = NULL;
#endif
- error = vfs_busy(mp, LK_NOWAIT, NULL);
+ error = vfs_busy(mp, MBF_NOWAIT);
if (error)
return (error);
error = nfs_nget(mp, (nfsfh_t *)nmp->nm_fh, nmp->nm_fhsize, &np,
LK_EXCLUSIVE);
Modified: head/sys/sys/mount.h
==============================================================================
--- head/sys/sys/mount.h Sun Nov 2 06:40:33 2008 (r184553)
+++ head/sys/sys/mount.h Sun Nov 2 10:15:42 2008 (r184554)
@@ -142,13 +142,11 @@ struct vfsopt;
* Lock reference:
* m - mountlist_mtx
* i - interlock
- * l - mnt_lock
*
* Unmarked fields are considered stable as long as a ref is held.
*
*/
struct mount {
- struct lock mnt_lock; /* mount structure lock */
struct mtx mnt_mtx; /* mount structure interlock */
int mnt_gen; /* struct mount generation */
#define mnt_startzero mnt_list
@@ -175,7 +173,7 @@ struct mount {
struct netexport *mnt_export; /* export list */
struct label *mnt_label; /* MAC label for the fs */
u_int mnt_hashseed; /* Random seed for vfs_hash */
- int mnt_markercnt; /* marker vnodes in use */
+ int mnt_lockref; /* (i) Lock reference count */
int mnt_holdcnt; /* hold count */
int mnt_holdcntwaiters; /* waits on hold count */
int mnt_secondary_writes; /* (i) # of secondary writes */
@@ -319,6 +317,7 @@ void __mnt_vnode_markerfree(str
#define MNTK_ASYNC 0x00000002 /* filtered async flag */
#define MNTK_SOFTDEP 0x00000004 /* async disabled by softdep */
#define MNTK_NOINSMNTQ 0x00000008 /* insmntque is not allowed */
+#define MNTK_DRAINING 0x00000010 /* lock draining is happening */
#define MNTK_UNMOUNT 0x01000000 /* unmount in progress */
#define MNTK_MWAIT 0x02000000 /* waiting for unmount to finish */
#define MNTK_SUSPEND 0x08000000 /* request write suspension */
@@ -506,6 +505,13 @@ struct uio;
#ifdef _KERNEL
+/*
+ * vfs_busy specific flags and mask.
+ */
+#define MBF_NOWAIT 0x01
+#define MBF_MNTLSTLOCK 0x02
+#define MBF_MASK (MBF_NOWAIT | MBF_MNTLSTLOCK)
+
#ifdef MALLOC_DECLARE
MALLOC_DECLARE(M_MOUNT);
#endif
@@ -686,7 +692,7 @@ int vfs_scanopt(struct vfsoptlist *opts,
int vfs_setpublicfs /* set publicly exported fs */
(struct mount *, struct netexport *, struct export_args *);
void vfs_msync(struct mount *, int);
-int vfs_busy(struct mount *, int, struct mtx *);
+int vfs_busy(struct mount *, int);
int vfs_export /* process mount export info */
(struct mount *, struct export_args *);
int vfs_allocate_syncvnode(struct mount *);
Modified: head/sys/ufs/ffs/ffs_softdep.c
==============================================================================
--- head/sys/ufs/ffs/ffs_softdep.c Sun Nov 2 06:40:33 2008
(r184553)
+++ head/sys/ufs/ffs/ffs_softdep.c Sun Nov 2 10:15:42 2008
(r184554)
@@ -745,7 +745,7 @@ softdep_flush(void)
nmp = TAILQ_NEXT(mp, mnt_list);
if ((mp->mnt_flag & MNT_SOFTDEP) == 0)
continue;
- if (vfs_busy(mp, LK_NOWAIT, &mountlist_mtx))
+ if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK))
continue;
vfslocked = VFS_LOCK_GIANT(mp);
softdep_process_worklist(mp, 0);
Modified: head/sys/ufs/ufs/ufs_vfsops.c
==============================================================================
--- head/sys/ufs/ufs/ufs_vfsops.c Sun Nov 2 06:40:33 2008
(r184553)
+++ head/sys/ufs/ufs/ufs_vfsops.c Sun Nov 2 10:15:42 2008
(r184554)
@@ -118,7 +118,7 @@ ufs_quotactl(mp, cmds, id, arg, td)
if ((u_int)type >= MAXQUOTAS)
return (EINVAL);
- if (vfs_busy(mp, LK_NOWAIT, 0))
+ if (vfs_busy(mp, MBF_NOWAIT))
return (0);
switch (cmd) {
