svn commit: r184652 - in head/sys: dev/hwpmc fs/procfs kern
John Baldwin
jhb at FreeBSD.org
Tue Nov 4 11:04:01 PST 2008
Author: jhb
Date: Tue Nov 4 19:04:01 2008
New Revision: 184652
URL: http://svn.freebsd.org/changeset/base/184652
Log:
Remove unnecessary locking around vn_fullpath(). The vnode lock for the
vnode in question does not need to be held. All the data structures used
during the name lookup are protected by the global name cache lock.
Instead, the caller merely needs to ensure a reference is held on the
vnode (such as vhold()) to keep it from being freed.
In the case of procfs' <pid>/file entry, grab the process lock while we
gain a new reference (via vhold()) on p_textvp to fully close races with
execve(2).
For the kern.proc.vmmap sysctl handler, use a shared vnode lock around
the call to VOP_GETATTR() rather than an exclusive lock.
MFC after: 1 month
Modified:
head/sys/dev/hwpmc/hwpmc_mod.c
head/sys/fs/procfs/procfs.c
head/sys/fs/procfs/procfs_map.c
head/sys/kern/kern_descrip.c
head/sys/kern/kern_proc.c
Modified: head/sys/dev/hwpmc/hwpmc_mod.c
==============================================================================
--- head/sys/dev/hwpmc/hwpmc_mod.c Tue Nov 4 18:56:12 2008 (r184651)
+++ head/sys/dev/hwpmc/hwpmc_mod.c Tue Nov 4 19:04:01 2008 (r184652)
@@ -680,9 +680,7 @@ pmc_getfilename(struct vnode *v, char **
*fullpath = "unknown";
*freepath = NULL;
- vn_lock(v, LK_CANRECURSE | LK_EXCLUSIVE | LK_RETRY);
vn_fullpath(curthread, v, fullpath, freepath);
- VOP_UNLOCK(v, 0);
}
/*
Modified: head/sys/fs/procfs/procfs.c
==============================================================================
--- head/sys/fs/procfs/procfs.c Tue Nov 4 18:56:12 2008 (r184651)
+++ head/sys/fs/procfs/procfs.c Tue Nov 4 19:04:01 2008 (r184652)
@@ -70,17 +70,13 @@ procfs_doprocfile(PFS_FILL_ARGS)
char *fullpath = "unknown";
char *freepath = NULL;
struct vnode *textvp;
- int err;
+ PROC_LOCK(p);
textvp = p->p_textvp;
- VI_LOCK(textvp);
- vholdl(textvp);
- err = vn_lock(textvp, LK_EXCLUSIVE | LK_INTERLOCK);
- vdrop(textvp);
- if (err)
- return (err);
+ vhold(textvp);
+ PROC_UNLOCK(p);
vn_fullpath(td, textvp, &fullpath, &freepath);
- VOP_UNLOCK(textvp, 0);
+ vdrop(textvp);
sbuf_printf(sb, "%s", fullpath);
if (freepath)
free(freepath, M_TEMP);
Modified: head/sys/fs/procfs/procfs_map.c
==============================================================================
--- head/sys/fs/procfs/procfs_map.c Tue Nov 4 18:56:12 2008 (r184651)
+++ head/sys/fs/procfs/procfs_map.c Tue Nov 4 19:04:01 2008 (r184652)
@@ -175,10 +175,9 @@ procfs_doprocmap(PFS_FILL_ARGS)
shadow_count = obj->shadow_count;
VM_OBJECT_UNLOCK(obj);
if (vp != NULL) {
- vfslocked = VFS_LOCK_GIANT(vp->v_mount);
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
vn_fullpath(td, vp, &fullpath, &freepath);
- vput(vp);
+ vfslocked = VFS_LOCK_GIANT(vp->v_mount);
+ vrele(vp);
VFS_UNLOCK_GIANT(vfslocked);
}
} else {
Modified: head/sys/kern/kern_descrip.c
==============================================================================
--- head/sys/kern/kern_descrip.c Tue Nov 4 18:56:12 2008 (r184651)
+++ head/sys/kern/kern_descrip.c Tue Nov 4 19:04:01 2008 (r184652)
@@ -2537,10 +2537,9 @@ export_vnode_for_sysctl(struct vnode *vp
freepath = NULL;
fullpath = "-";
FILEDESC_SUNLOCK(fdp);
- vfslocked = VFS_LOCK_GIANT(vp->v_mount);
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
vn_fullpath(curthread, vp, &fullpath, &freepath);
- vput(vp);
+ vfslocked = VFS_LOCK_GIANT(vp->v_mount);
+ vrele(vp);
VFS_UNLOCK_GIANT(vfslocked);
strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path));
if (freepath != NULL)
@@ -2708,10 +2707,9 @@ sysctl_kern_proc_filedesc(SYSCTL_HANDLER
freepath = NULL;
fullpath = "-";
FILEDESC_SUNLOCK(fdp);
- vfslocked = VFS_LOCK_GIANT(vp->v_mount);
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
vn_fullpath(curthread, vp, &fullpath, &freepath);
- vput(vp);
+ vfslocked = VFS_LOCK_GIANT(vp->v_mount);
+ vrele(vp);
VFS_UNLOCK_GIANT(vfslocked);
strlcpy(kif->kf_path, fullpath,
sizeof(kif->kf_path));
Modified: head/sys/kern/kern_proc.c
==============================================================================
--- head/sys/kern/kern_proc.c Tue Nov 4 18:56:12 2008 (r184651)
+++ head/sys/kern/kern_proc.c Tue Nov 4 19:04:01 2008 (r184652)
@@ -1440,11 +1440,11 @@ sysctl_kern_proc_vmmap(SYSCTL_HANDLER_AR
kve->kve_shadow_count = obj->shadow_count;
VM_OBJECT_UNLOCK(obj);
if (vp != NULL) {
- vfslocked = VFS_LOCK_GIANT(vp->v_mount);
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
vn_fullpath(curthread, vp, &fullpath,
&freepath);
cred = curthread->td_ucred;
+ vfslocked = VFS_LOCK_GIANT(vp->v_mount);
+ vn_lock(vp, LK_SHARED | LK_RETRY);
if (VOP_GETATTR(vp, &va, cred) == 0) {
kve->kve_fileid = va.va_fileid;
kve->kve_fsid = va.va_fsid;
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