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Forcibly remove the cached items from pseudofs vncache on module unload.

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If some process' nodes were accessed using procfs and the process
cannot exit properly at the time modunload event is reported to the
pseudofs-backed filesystem, the assertion in pfs_vncache_unload() is
triggered.  Assertion is correct, the cache should be cleaned.

Approved by:	des (pseudofs maintainer)
Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2017-01-09 20:14:18 +00:00
parent 3ac0e4769e
commit d72b4d3918
1 changed files with 9 additions and 4 deletions
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13
sys/fs/pseudofs/pseudofs_vncache.c
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@ -51,6 +51,7 @@ static struct mtx pfs_vncache_mutex;
static struct pfs_vdata *pfs_vncache;
static eventhandler_tag pfs_exit_tag;
static void pfs_exit(void *arg, struct proc *p);
static void pfs_purge_locked(struct pfs_node *pn, bool force);
static SYSCTL_NODE(_vfs_pfs, OID_AUTO, vncache, CTLFLAG_RW, 0,
"pseudofs vnode cache");
@ -97,6 +98,9 @@ pfs_vncache_unload(void)
{
EVENTHANDLER_DEREGISTER(process_exit, pfs_exit_tag);
mtx_lock(&pfs_vncache_mutex);
pfs_purge_locked(NULL, true);
mtx_unlock(&pfs_vncache_mutex);
KASSERT(pfs_vncache_entries == 0,
("%d vncache entries remaining", pfs_vncache_entries));
mtx_destroy(&pfs_vncache_mutex);
@ -272,7 +276,7 @@ pfs_vncache_free(struct vnode *vp)
* used to implement the cache.
*/
static void
pfs_purge_locked(struct pfs_node *pn)
pfs_purge_locked(struct pfs_node *pn, bool force)
{
struct pfs_vdata *pvd;
struct vnode *vnp;
@ -280,7 +284,8 @@ pfs_purge_locked(struct pfs_node *pn)
mtx_assert(&pfs_vncache_mutex, MA_OWNED);
pvd = pfs_vncache;
while (pvd != NULL) {
if (pvd->pvd_dead || (pn != NULL && pvd->pvd_pn == pn)) {
if (force || pvd->pvd_dead ||
(pn != NULL && pvd->pvd_pn == pn)) {
vnp = pvd->pvd_vnode;
vhold(vnp);
mtx_unlock(&pfs_vncache_mutex);
@ -301,7 +306,7 @@ pfs_purge(struct pfs_node *pn)
{
mtx_lock(&pfs_vncache_mutex);
pfs_purge_locked(pn);
pfs_purge_locked(pn, false);
mtx_unlock(&pfs_vncache_mutex);
}
@ -321,6 +326,6 @@ pfs_exit(void *arg, struct proc *p)
if (pvd->pvd_pid == p->p_pid)
dead = pvd->pvd_dead = 1;
if (dead)
pfs_purge_locked(NULL);
pfs_purge_locked(NULL, false);
mtx_unlock(&pfs_vncache_mutex);
}