Author: kib
Date: Tue Feb 4 17:17:40 2020
New Revision: 357508
URL: https://svnweb.freebsd.org/changeset/base/357508
Log:
MFC r357199, r357306:
Save lower root vnode in nullfs mnt data instead of upper.
Modified:
stable/11/sys/fs/nullfs/null.h
stable/11/sys/fs/nullfs/null_subr.c
stable/11/sys/fs/nullfs/null_vfsops.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/sys/fs/nullfs/null.h
==============================================================================
--- stable/11/sys/fs/nullfs/null.h Tue Feb 4 17:15:51 2020
(r357507)
+++ stable/11/sys/fs/nullfs/null.h Tue Feb 4 17:17:40 2020
(r357508)
@@ -41,7 +41,7 @@
struct null_mount {
struct mount *nullm_vfs;
- struct vnode *nullm_rootvp; /* Reference to root null_node */
+ struct vnode *nullm_lowerrootvp; /* Ref to lower root vnode */
uint64_t nullm_flags;
};
Modified: stable/11/sys/fs/nullfs/null_subr.c
==============================================================================
--- stable/11/sys/fs/nullfs/null_subr.c Tue Feb 4 17:15:51 2020
(r357507)
+++ stable/11/sys/fs/nullfs/null_subr.c Tue Feb 4 17:17:40 2020
(r357508)
@@ -254,6 +254,9 @@ null_nodeget(mp, lowervp, vpp)
error = insmntque1(vp, mp, null_insmntque_dtr, xp);
if (error != 0)
return (error);
+ if (lowervp == MOUNTTONULLMOUNT(mp)->nullm_lowerrootvp)
+ vp->v_vflag |= VV_ROOT;
+
/*
* Atomically insert our new node into the hash or vget existing
* if someone else has beaten us to it.
Modified: stable/11/sys/fs/nullfs/null_vfsops.c
==============================================================================
--- stable/11/sys/fs/nullfs/null_vfsops.c Tue Feb 4 17:15:51 2020
(r357507)
+++ stable/11/sys/fs/nullfs/null_vfsops.c Tue Feb 4 17:17:40 2020
(r357508)
@@ -72,7 +72,7 @@ static vfs_extattrctl_t nullfs_extattrctl;
static int
nullfs_mount(struct mount *mp)
{
- struct vnode *lowerrootvp, *vp;
+ struct vnode *lowerrootvp;
struct vnode *nullm_rootvp;
struct null_mount *xmp;
struct thread *td = curthread;
@@ -159,36 +159,24 @@ nullfs_mount(struct mount *mp)
M_NULLFSMNT, M_WAITOK | M_ZERO);
/*
- * Save reference to underlying FS
+ * Save pointer to underlying FS and the reference to the
+ * lower root vnode.
*/
xmp->nullm_vfs = lowerrootvp->v_mount;
+ vref(lowerrootvp);
+ xmp->nullm_lowerrootvp = lowerrootvp;
+ mp->mnt_data = xmp;
/*
- * Save reference. Each mount also holds
- * a reference on the root vnode.
+ * Make sure the node alias worked.
*/
- error = null_nodeget(mp, lowerrootvp, &vp);
- /*
- * Make sure the node alias worked
- */
- if (error) {
+ error = null_nodeget(mp, lowerrootvp, &nullm_rootvp);
+ if (error != 0) {
+ vrele(lowerrootvp);
free(xmp, M_NULLFSMNT);
return (error);
}
- /*
- * Keep a held reference to the root vnode.
- * It is vrele'd in nullfs_unmount.
- */
- nullm_rootvp = vp;
- nullm_rootvp->v_vflag |= VV_ROOT;
- xmp->nullm_rootvp = nullm_rootvp;
-
- /*
- * Unlock the node (either the lower or the alias)
- */
- VOP_UNLOCK(vp, 0);
-
if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) {
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_LOCAL;
@@ -210,7 +198,6 @@ nullfs_mount(struct mount *mp)
mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag &
(MNTK_USES_BCACHE | MNTK_NO_IOPF | MNTK_UNMAPPED_BUFS);
MNT_IUNLOCK(mp);
- mp->mnt_data = xmp;
vfs_getnewfsid(mp);
if ((xmp->nullm_flags & NULLM_CACHE) != 0) {
MNT_ILOCK(xmp->nullm_vfs);
@@ -220,6 +207,7 @@ nullfs_mount(struct mount *mp)
}
vfs_mountedfrom(mp, target);
+ vput(nullm_rootvp);
NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
@@ -236,7 +224,7 @@ nullfs_unmount(mp, mntflags)
{
struct null_mount *mntdata;
struct mount *ump;
- int error, flags, rootrefs;
+ int error, flags;
NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
@@ -245,9 +233,9 @@ nullfs_unmount(mp, mntflags)
else
flags = 0;
- for (rootrefs = 1;; rootrefs = 0) {
+ for (;;) {
/* There is 1 extra root vnode reference (nullm_rootvp). */
- error = vflush(mp, rootrefs, flags, curthread);
+ error = vflush(mp, 0, flags, curthread);
if (error)
return (error);
MNT_ILOCK(mp);
@@ -274,6 +262,7 @@ nullfs_unmount(mp, mntflags)
TAILQ_REMOVE(&ump->mnt_uppers, mp, mnt_upper_link);
MNT_IUNLOCK(ump);
}
+ vrele(mntdata->nullm_lowerrootvp);
mp->mnt_data = NULL;
free(mntdata, M_NULLFSMNT);
return (0);
@@ -286,21 +275,24 @@ nullfs_root(mp, flags, vpp)
struct vnode **vpp;
{
struct vnode *vp;
+ struct null_mount *mntdata;
+ int error;
- NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
- (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
- (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
+ mntdata = MOUNTTONULLMOUNT(mp);
+ NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", mp,
+ mntdata->nullm_lowerrootvp);
- /*
- * Return locked reference to root.
- */
- vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
- VREF(vp);
-
- ASSERT_VOP_UNLOCKED(vp, "root vnode is locked");
- vn_lock(vp, flags | LK_RETRY);
- *vpp = vp;
- return 0;
+ error = vget(mntdata->nullm_lowerrootvp, (flags & ~LK_TYPE_MASK) |
+ LK_EXCLUSIVE, curthread);
+ if (error == 0) {
+ error = null_nodeget(mp, mntdata->nullm_lowerrootvp, &vp);
+ if (error == 0) {
+ if ((flags & LK_TYPE_MASK) == LK_SHARED)
+ vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
+ *vpp = vp;
+ }
+ }
+ return (error);
}
static int
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