Page MenuHomeFreeBSD
Files F149526922

D30401.diff
No OneTemporary
Actions

D30401.diff
View Options

diff --git a/sys/fs/nullfs/null_vfsops.c b/sys/fs/nullfs/null_vfsops.c
--- a/sys/fs/nullfs/null_vfsops.c
+++ b/sys/fs/nullfs/null_vfsops.c
@@ -163,7 +163,12 @@
* Save pointer to underlying FS and the reference to the
* lower root vnode.
*/
- xmp->nullm_vfs = lowerrootvp->v_mount;
+ xmp->nullm_vfs = vfs_pin_from_vp(lowerrootvp);
+ if (xmp->nullm_vfs == NULL) {
+ vput(lowerrootvp);
+ free(xmp, M_NULLFSMNT);
+ return (ENOENT);
+ }
vref(lowerrootvp);
xmp->nullm_lowerrootvp = lowerrootvp;
mp->mnt_data = xmp;
@@ -173,6 +178,7 @@
*/
error = null_nodeget(mp, lowerrootvp, &nullm_rootvp);
if (error != 0) {
+ vfs_unpin(xmp->nullm_vfs);
vrele(lowerrootvp);
free(xmp, M_NULLFSMNT);
return (error);
@@ -263,6 +269,7 @@
TAILQ_REMOVE(&ump->mnt_uppers, mp, mnt_upper_link);
MNT_IUNLOCK(ump);
}
+ vfs_unpin(ump);
vrele(mntdata->nullm_lowerrootvp);
mp->mnt_data = NULL;
free(mntdata, M_NULLFSMNT);
diff --git a/sys/fs/unionfs/union_vfsops.c b/sys/fs/unionfs/union_vfsops.c
--- a/sys/fs/unionfs/union_vfsops.c
+++ b/sys/fs/unionfs/union_vfsops.c
@@ -75,6 +75,7 @@
unionfs_domount(struct mount *mp)
{
int error;
+ struct mount *lowermp, *uppermp;
struct vnode *lowerrootvp;
struct vnode *upperrootvp;
struct unionfs_mount *ump;
@@ -285,15 +286,28 @@
error = unionfs_nodeget(mp, ump->um_uppervp, ump->um_lowervp,
NULLVP, &(ump->um_rootvp), NULL, td);
vrele(upperrootvp);
- if (error) {
+ if (error != 0) {
free(ump, M_UNIONFSMNT);
mp->mnt_data = NULL;
return (error);
}
+ lowermp = vfs_pin_from_vp(ump->um_lowervp);
+ uppermp = vfs_pin_from_vp(ump->um_uppervp);
+
+ if (lowermp == NULL || uppermp == NULL) {
+ if (lowermp != NULL)
+ vfs_unpin(lowermp);
+ if (uppermp != NULL)
+ vfs_unpin(uppermp);
+ free(ump, M_UNIONFSMNT);
+ mp->mnt_data = NULL;
+ return (ENOENT);
+ }
+
MNT_ILOCK(mp);
- if ((ump->um_lowervp->v_mount->mnt_flag & MNT_LOCAL) &&
- (ump->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
+ if ((lowermp->mnt_flag & MNT_LOCAL) != 0 &&
+ (uppermp->mnt_flag & MNT_LOCAL) != 0)
mp->mnt_flag |= MNT_LOCAL;
mp->mnt_kern_flag |= MNTK_NOMSYNC | MNTK_UNIONFS;
MNT_IUNLOCK(mp);
@@ -343,6 +357,8 @@
if (error)
return (error);
+ vfs_unpin(ump->um_lowervp->v_mount);
+ vfs_unpin(ump->um_uppervp->v_mount);
free(ump, M_UNIONFSMNT);
mp->mnt_data = NULL;
diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -49,6 +49,7 @@
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/libkern.h>
+#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mutex.h>
@@ -504,6 +505,39 @@
MNT_IUNLOCK(mp);
}
+struct mount *
+vfs_pin_from_vp(struct vnode *vp)
+{
+ struct mount *mp;
+
+ mp = atomic_load_ptr(&vp->v_mount);
+ if (mp == NULL)
+ return (NULL);
+ MNT_ILOCK(mp);
+ if (mp != vp->v_mount || (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
+ MNT_IUNLOCK(mp);
+ return (NULL);
+ }
+ MNT_REF(mp);
+ KASSERT(mp->mnt_pinned_count < INT_MAX,
+ ("mount pinned count overflow"));
+ ++mp->mnt_pinned_count;
+ MNT_IUNLOCK(mp);
+ return (mp);
+}
+
+void
+vfs_unpin(struct mount *mp)
+{
+ MNT_ILOCK(mp);
+ KASSERT(mp->mnt_pinned_count > 0, ("mount pinned count underflow"));
+ KASSERT((mp->mnt_kern_flag & MNTK_UNMOUNT) == 0,
+ ("mount pinned with pending unmount"));
+ --mp->mnt_pinned_count;
+ MNT_REL(mp);
+ MNT_IUNLOCK(mp);
+}
+
void
vfs_rel(struct mount *mp)
{
@@ -567,6 +601,7 @@
#endif
arc4rand(&mp->mnt_hashseed, sizeof mp->mnt_hashseed, 0);
TAILQ_INIT(&mp->mnt_uppers);
+ mp->mnt_pinned_count = 0;
return (mp);
}
@@ -605,6 +640,8 @@
vn_printf(vp, "dangling vnode ");
panic("unmount: dangling vnode");
}
+ KASSERT(mp->mnt_pinned_count == 0,
+ ("mnt_pinned_count = %d", mp->mnt_pinned_count));
KASSERT(TAILQ_EMPTY(&mp->mnt_uppers), ("mnt_uppers"));
if (mp->mnt_nvnodelistsize != 0)
panic("vfs_mount_destroy: nonzero nvnodelistsize");
@@ -1811,7 +1848,7 @@
MNT_ILOCK(mp);
if ((mp->mnt_kern_flag & MNTK_UNMOUNT) != 0 ||
(mp->mnt_flag & MNT_UPDATE) != 0 ||
- !TAILQ_EMPTY(&mp->mnt_uppers)) {
+ mp->mnt_pinned_count != 0) {
dounmount_cleanup(mp, coveredvp, 0);
return (EBUSY);
}
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -831,6 +831,9 @@
* valid.
*/
while (mp->mnt_kern_flag & MNTK_UNMOUNT) {
+ KASSERT(mp->mnt_pinned_count == 0,
+ ("%s: non-zero pinned count %d with pending unmount",
+ __func__, mp->mnt_pinned_count));
if (flags & MBF_NOWAIT || mp->mnt_kern_flag & MNTK_REFEXPIRE) {
MNT_REL(mp);
MNT_IUNLOCK(mp);
diff --git a/sys/sys/mount.h b/sys/sys/mount.h
--- a/sys/sys/mount.h
+++ b/sys/sys/mount.h
@@ -242,6 +242,7 @@
struct mtx mnt_listmtx;
struct vnodelst mnt_lazyvnodelist; /* (l) list of lazy vnodes */
int mnt_lazyvnodelistsize; /* (l) # of lazy vnodes */
+ int mnt_pinned_count; /* (i) unmount prevented */
struct lock mnt_explock; /* vfs_export walkers lock */
TAILQ_ENTRY(mount) mnt_upper_link; /* (i*) we in the all uppers */
TAILQ_HEAD(, mount) mnt_uppers; /* (i) upper mounts over us */
@@ -1011,6 +1012,8 @@
int vfs_suser(struct mount *, struct thread *);
void vfs_unbusy(struct mount *);
void vfs_unmountall(void);
+struct mount *vfs_pin_from_vp(struct vnode *);
+void vfs_unpin(struct mount *);
extern TAILQ_HEAD(mntlist, mount) mountlist; /* mounted filesystem list */
extern struct mtx_padalign mountlist_mtx;
extern struct nfs_public nfs_pub;

File Metadata

Mime Type
text/plain
Expires
Thu, Mar 26, 1:00 AM (4 h, 1 m)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
30356450
Default Alt Text
D30401.diff (5 KB)

Event Timeline