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Allow vdrop() of a vnode not yet on the per-mount list after r306512.

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The old code allowed calling vdrop() before insmntque() to place the vnode back
onto the freelist for later recycling.  Some downstream consumers may rely on
this support.  Normally insmntque() failing is fine since is uses vgone() and
immediately frees the vnode rather than attempting to add it to the freelist if
vdrop() were used instead.

Also assert that vhold() cannot be used on such a vnode.

Reviewed by:	kib, cem, markj
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D12126
This commit is contained in:
bdrewery 2017-08-28 19:29:51 +00:00
parent dfcd3e3b61
commit 79ee71cc38
1 changed files with 29 additions and 13 deletions
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42
sys/kern/vfs_subr.c
View File

@ -2861,6 +2861,8 @@ _vhold(struct vnode *vp, bool locked)
* Remove a vnode from the free list, mark it as in use,
* and put it on the active list.
*/
VNASSERT(vp->v_mount != NULL, vp,
("_vhold: vnode not on per mount vnode list"));
mp = vp->v_mount;
mtx_lock(&mp->mnt_listmtx);
if ((vp->v_mflag & VMP_TMPMNTFREELIST) != 0) {
@ -2935,21 +2937,35 @@ _vdrop(struct vnode *vp, bool locked)
if ((vp->v_iflag & VI_OWEINACT) == 0) {
vp->v_iflag &= ~VI_ACTIVE;
mp = vp->v_mount;
mtx_lock(&mp->mnt_listmtx);
if (active) {
TAILQ_REMOVE(&mp->mnt_activevnodelist, vp,
if (mp != NULL) {
mtx_lock(&mp->mnt_listmtx);
if (active) {
TAILQ_REMOVE(&mp->mnt_activevnodelist,
vp, v_actfreelist);
mp->mnt_activevnodelistsize--;
}
TAILQ_INSERT_TAIL(&mp->mnt_tmpfreevnodelist,
vp, v_actfreelist);
mp->mnt_tmpfreevnodelistsize++;
vp->v_iflag |= VI_FREE;
vp->v_mflag |= VMP_TMPMNTFREELIST;
VI_UNLOCK(vp);
if (mp->mnt_tmpfreevnodelistsize >=
mnt_free_list_batch)
vnlru_return_batch_locked(mp);
mtx_unlock(&mp->mnt_listmtx);
} else {
VNASSERT(active == 0, vp,
("vdropl: active vnode not on per mount "
"vnode list"));
mtx_lock(&vnode_free_list_mtx);
TAILQ_INSERT_TAIL(&vnode_free_list, vp,
v_actfreelist);
mp->mnt_activevnodelistsize--;
freevnodes++;
vp->v_iflag |= VI_FREE;
VI_UNLOCK(vp);
mtx_unlock(&vnode_free_list_mtx);
}
TAILQ_INSERT_TAIL(&mp->mnt_tmpfreevnodelist, vp,
v_actfreelist);
mp->mnt_tmpfreevnodelistsize++;
vp->v_iflag |= VI_FREE;
vp->v_mflag |= VMP_TMPMNTFREELIST;
VI_UNLOCK(vp);
if (mp->mnt_tmpfreevnodelistsize >= mnt_free_list_batch)
vnlru_return_batch_locked(mp);
mtx_unlock(&mp->mnt_listmtx);
} else {
VI_UNLOCK(vp);
counter_u64_add(free_owe_inact, 1);