Author: kib
Date: Fri Mar 11 11:51:38 2016
New Revision: 296652
URL: https://svnweb.freebsd.org/changeset/base/296652
Log:
Do not perform unneccessary shared recursion on the allproc_lock in
pfs_visible(). The recursion does not cause deadlock because the sx
implementation does not prefer exclusive waiters over the shared, but
this is an implementation detail.
Reported by: pho, Matthew Bryan <matthew.br...@isilon.com>
Reviewed by: jhb
Tested by: pho
Approved by: des (pseudofs maintainer)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Modified:
head/sys/fs/pseudofs/pseudofs_vnops.c
Modified: head/sys/fs/pseudofs/pseudofs_vnops.c
==============================================================================
--- head/sys/fs/pseudofs/pseudofs_vnops.c Fri Mar 11 11:38:31 2016
(r296651)
+++ head/sys/fs/pseudofs/pseudofs_vnops.c Fri Mar 11 11:51:38 2016
(r296652)
@@ -104,7 +104,8 @@ pfs_visible_proc(struct thread *td, stru
}
static int
-pfs_visible(struct thread *td, struct pfs_node *pn, pid_t pid, struct proc **p)
+pfs_visible(struct thread *td, struct pfs_node *pn, pid_t pid,
+ bool allproc_locked, struct proc **p)
{
struct proc *proc;
@@ -115,7 +116,8 @@ pfs_visible(struct thread *td, struct pf
*p = NULL;
if (pid == NO_PID)
PFS_RETURN (1);
- if ((proc = pfind(pid)) == NULL)
+ proc = allproc_locked ? pfind_locked(pid) : pfind(pid);
+ if (proc == NULL)
PFS_RETURN (0);
if (pfs_visible_proc(td, pn, proc)) {
if (p)
@@ -202,7 +204,7 @@ pfs_getattr(struct vop_getattr_args *va)
PFS_TRACE(("%s", pn->pn_name));
pfs_assert_not_owned(pn);
- if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc))
+ if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
PFS_RETURN (ENOENT);
vap->va_type = vn->v_type;
@@ -293,7 +295,7 @@ pfs_ioctl(struct vop_ioctl_args *va)
* This is necessary because process' privileges may
* have changed since the open() call.
*/
- if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc)) {
+ if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc)) {
VOP_UNLOCK(vn, 0);
PFS_RETURN (EIO);
}
@@ -326,7 +328,7 @@ pfs_getextattr(struct vop_getextattr_arg
* This is necessary because either process' privileges may
* have changed since the open() call.
*/
- if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc))
+ if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
PFS_RETURN (EIO);
if (pn->pn_getextattr == NULL)
@@ -462,7 +464,7 @@ pfs_lookup(struct vop_cachedlookup_args
PFS_RETURN (ENOENT);
/* check that parent directory is visible... */
- if (!pfs_visible(curthread, pd, pvd->pvd_pid, NULL))
+ if (!pfs_visible(curthread, pd, pvd->pvd_pid, false, NULL))
PFS_RETURN (ENOENT);
/* self */
@@ -546,7 +548,7 @@ pfs_lookup(struct vop_cachedlookup_args
got_pnode:
pfs_assert_not_owned(pd);
pfs_assert_not_owned(pn);
- visible = pfs_visible(curthread, pn, pid, NULL);
+ visible = pfs_visible(curthread, pn, pid, false, NULL);
if (!visible) {
error = ENOENT;
goto failed;
@@ -635,7 +637,7 @@ pfs_read(struct vop_read_args *va)
* This is necessary because either process' privileges may
* have changed since the open() call.
*/
- if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc))
+ if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
PFS_RETURN (EIO);
if (proc != NULL) {
_PHOLD(proc);
@@ -791,7 +793,7 @@ pfs_readdir(struct vop_readdir_args *va)
pfs_lock(pd);
/* check if the directory is visible to the caller */
- if (!pfs_visible(curthread, pd, pid, &proc)) {
+ if (!pfs_visible(curthread, pd, pid, true, &proc)) {
sx_sunlock(&allproc_lock);
pfs_unlock(pd);
PFS_RETURN (ENOENT);
@@ -995,7 +997,7 @@ pfs_write(struct vop_write_args *va)
* This is necessary because either process' privileges may
* have changed since the open() call.
*/
- if (!pfs_visible(curthread, pn, pvd->pvd_pid, &proc))
+ if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
PFS_RETURN (EIO);
if (proc != NULL) {
_PHOLD(proc);
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
