Module Name: src
Committed By: hannken
Date: Wed Nov 23 19:39:11 UTC 2011
Modified Files:
src/sys/fs/union: union.h union_subr.c union_vfsops.c
Log Message:
Use hashinit() / hashdone() to create the union node hash list.
Cleanup the hash lookup in union_allocvp().
Needs more work as there is still a possible deadlock between
union_allocvp() and vclean().
To generate a diff of this commit:
cvs rdiff -u -r1.22 -r1.23 src/sys/fs/union/union.h
cvs rdiff -u -r1.53 -r1.54 src/sys/fs/union/union_subr.c
cvs rdiff -u -r1.65 -r1.66 src/sys/fs/union/union_vfsops.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/fs/union/union.h
diff -u src/sys/fs/union/union.h:1.22 src/sys/fs/union/union.h:1.23
--- src/sys/fs/union/union.h:1.22 Mon Nov 21 18:29:22 2011
+++ src/sys/fs/union/union.h Wed Nov 23 19:39:11 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: union.h,v 1.22 2011/11/21 18:29:22 hannken Exp $ */
+/* $NetBSD: union.h,v 1.23 2011/11/23 19:39:11 hannken Exp $ */
/*
* Copyright (c) 1994 The Regents of the University of California.
@@ -175,6 +175,7 @@ int union_readdirhook(struct vnode **, s
extern int (**union_vnodeop_p)(void *);
void union_init(void);
+void union_reinit(void);
void union_done(void);
int union_freevp(struct vnode *);
Index: src/sys/fs/union/union_subr.c
diff -u src/sys/fs/union/union_subr.c:1.53 src/sys/fs/union/union_subr.c:1.54
--- src/sys/fs/union/union_subr.c:1.53 Mon Nov 21 18:29:22 2011
+++ src/sys/fs/union/union_subr.c Wed Nov 23 19:39:11 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: union_subr.c,v 1.53 2011/11/21 18:29:22 hannken Exp $ */
+/* $NetBSD: union_subr.c,v 1.54 2011/11/23 19:39:11 hannken Exp $ */
/*
* Copyright (c) 1994
@@ -72,7 +72,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.53 2011/11/21 18:29:22 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: union_subr.c,v 1.54 2011/11/23 19:39:11 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -96,15 +96,13 @@ __KERNEL_RCSID(0, "$NetBSD: union_subr.c
#include <miscfs/genfs/genfs.h>
#include <miscfs/specfs/specdev.h>
-/* must be power of two, otherwise change UNION_HASH() */
-#define NHASH 32
-
-/* unsigned int ... */
+static LIST_HEAD(uhashhead, union_node) *uhashtbl;
+static u_long uhash_mask; /* size of hash table - 1 */
#define UNION_HASH(u, l) \
- (((((unsigned long) (u)) + ((unsigned long) l)) >> 8) & (NHASH-1))
+ ((((u_long) (u) + (u_long) (l)) >> 8) & uhash_mask)
+#define NOHASH ((u_long)-1)
-static LIST_HEAD(unhead, union_node) unhead[NHASH];
-static kmutex_t unheadlock[NHASH];
+static kmutex_t uhash_lock;
void union_updatevp(struct union_node *, struct vnode *, struct vnode *);
static int union_do_lookup(struct vnode *, struct componentname *, kauth_cred_t, const char *, u_long);
@@ -115,12 +113,34 @@ struct vnode *union_dircache(struct vnod
void
union_init(void)
{
+
+ mutex_init(&uhash_lock, MUTEX_DEFAULT, IPL_NONE);
+ uhashtbl = hashinit(desiredvnodes, HASH_LIST, true, &uhash_mask);
+}
+
+void
+union_reinit(void)
+{
+ struct union_node *un;
+ struct uhashhead *oldhash, *hash;
+ u_long oldmask, mask, val;
int i;
- for (i = 0; i < NHASH; i++) {
- LIST_INIT(&unhead[i]);
- mutex_init(&unheadlock[i], MUTEX_DEFAULT, IPL_NONE);
+ hash = hashinit(desiredvnodes, HASH_LIST, true, &mask);
+ mutex_enter(&uhash_lock);
+ oldhash = uhashtbl;
+ oldmask = uhash_mask;
+ uhashtbl = hash;
+ uhash_mask = mask;
+ for (i = 0; i <= oldmask; i++) {
+ while ((un = LIST_FIRST(&oldhash[i])) != NULL) {
+ LIST_REMOVE(un, un_cache);
+ val = UNION_HASH(un->un_uppervp, un->un_lowervp);
+ LIST_INSERT_HEAD(&hash[val], un, un_cache);
+ }
}
+ mutex_exit(&uhash_lock);
+ hashdone(oldhash, HASH_LIST, oldmask);
}
/*
@@ -129,10 +149,9 @@ union_init(void)
void
union_done(void)
{
- int i;
- for (i = 0; i < NHASH; i++)
- mutex_destroy(&unheadlock[i]);
+ hashdone(uhashtbl, HASH_LIST, uhash_mask);
+ mutex_destroy(&uhash_lock);
/* Make sure to unset the readdir hook. */
vn_union_readdir_hook = NULL;
@@ -145,37 +164,19 @@ union_updatevp(struct union_node *un, st
int ohash = UNION_HASH(un->un_uppervp, un->un_lowervp);
int nhash = UNION_HASH(uppervp, lowervp);
int docache = (lowervp != NULLVP || uppervp != NULLVP);
- int lhash, uhash;
bool un_unlock;
KASSERT(VOP_ISLOCKED(UNIONTOV(un)) == LK_EXCLUSIVE);
- /*
- * Ensure locking is ordered from lower to higher
- * to avoid deadlocks.
- */
- if (nhash < ohash) {
- lhash = nhash;
- uhash = ohash;
- } else {
- lhash = ohash;
- uhash = nhash;
- }
-
- if (lhash != uhash)
- mutex_enter(&unheadlock[lhash]);
- mutex_enter(&unheadlock[uhash]);
+ mutex_enter(&uhash_lock);
- if (ohash != nhash || !docache) {
+ if (!docache || ohash != nhash) {
if (un->un_cflags & UN_CACHED) {
un->un_cflags &= ~UN_CACHED;
LIST_REMOVE(un, un_cache);
}
}
- if (ohash != nhash)
- mutex_exit(&unheadlock[ohash]);
-
if (un->un_lowervp != lowervp) {
if (un->un_lowervp) {
vrele(un->un_lowervp);
@@ -222,11 +223,11 @@ union_updatevp(struct union_node *un, st
}
if (docache && (ohash != nhash)) {
- LIST_INSERT_HEAD(&unhead[nhash], un, un_cache);
+ LIST_INSERT_HEAD(&uhashtbl[nhash], un, un_cache);
un->un_cflags |= UN_CACHED;
}
- mutex_exit(&unheadlock[nhash]);
+ mutex_exit(&uhash_lock);
}
void
@@ -337,8 +338,8 @@ union_allocvp(
struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
voff_t uppersz, lowersz;
dev_t rdev;
- int hash = 0;
- int vflag, iflag;
+ u_long hash[3];
+ int vflag, iflag, lflag;
int try;
if (uppervp)
@@ -366,62 +367,53 @@ union_allocvp(
vflag = VV_ROOT;
}
-loop:
if (!docache) {
- un = 0;
- } else for (try = 0; try < 3; try++) {
- switch (try) {
- case 0:
- if (lowervp == NULLVP)
- continue;
- hash = UNION_HASH(uppervp, lowervp);
- break;
+ un = NULL;
+ goto found;
+ }
- case 1:
- if (uppervp == NULLVP)
- continue;
- hash = UNION_HASH(uppervp, NULLVP);
- break;
+ /*
+ * If both uppervp and lowervp are not NULL we have to
+ * search union nodes with one vnode as NULL too.
+ */
+ hash[0] = UNION_HASH(uppervp, lowervp);
+ if (uppervp == NULL || lowervp == NULL) {
+ hash[1] = hash[2] = NOHASH;
+ } else {
+ hash[1] = UNION_HASH(uppervp, NULLVP);
+ hash[2] = UNION_HASH(NULLVP, lowervp);
+ }
- case 2:
- if (lowervp == NULLVP)
- continue;
- hash = UNION_HASH(NULLVP, lowervp);
- break;
- }
+loop:
+ mutex_enter(&uhash_lock);
- mutex_enter(&unheadlock[hash]);
+ for (try = 0; try < 3; try++) {
+ if (hash[try] == NOHASH)
+ continue;
+ LIST_FOREACH(un, &uhashtbl[hash[try]], un_cache) {
+ if ((un->un_lowervp && un->un_lowervp != lowervp) ||
+ (un->un_uppervp && un->un_uppervp != uppervp) ||
+ UNIONTOV(un)->v_mount != mp)
+ continue;
- for (un = unhead[hash].lh_first; un != 0;
- un = un->un_cache.le_next) {
- if ((un->un_lowervp == lowervp ||
- un->un_lowervp == NULLVP) &&
- (un->un_uppervp == uppervp ||
- un->un_uppervp == NULLVP) &&
- (UNIONTOV(un)->v_mount == mp)) {
- int lflag;
-
- if (uppervp != NULL && (uppervp == dvp ||
- uppervp == un->un_uppervp))
- /* "." or already locked. */
- lflag = 0;
- else
- lflag = LK_EXCLUSIVE;
- vp = UNIONTOV(un);
- mutex_enter(vp->v_interlock);
- mutex_exit(&unheadlock[hash]);
- if (vget(vp, lflag))
- goto loop;
- break;
- }
+ if (uppervp != NULL &&
+ (uppervp == dvp || uppervp == un->un_uppervp))
+ /* "." or already locked. */
+ lflag = 0;
+ else
+ lflag = LK_EXCLUSIVE;
+ vp = UNIONTOV(un);
+ mutex_enter(vp->v_interlock);
+ mutex_exit(&uhash_lock);
+ if (vget(vp, lflag))
+ goto loop;
+ goto found;
}
-
- if (un)
- break;
-
- mutex_exit(&unheadlock[hash]);
}
+ mutex_exit(&uhash_lock);
+
+found:
if (un) {
KASSERT(VOP_ISLOCKED(UNIONTOV(un)) == LK_EXCLUSIVE);
KASSERT(uppervp == NULL ||
@@ -474,7 +466,6 @@ loop:
if (error == 0)
lowersz = va.va_size;
}
- hash = UNION_HASH(uppervp, lowervp);
/*
* Get a new vnode and share the lock with upper layer vnode,
@@ -497,8 +488,8 @@ loop:
}
if (docache) {
- mutex_enter(&unheadlock[hash]);
- LIST_FOREACH(un1, &unhead[hash], un_cache) {
+ mutex_enter(&uhash_lock);
+ LIST_FOREACH(un1, &uhashtbl[hash[0]], un_cache) {
if (un1->un_lowervp == lowervp &&
un1->un_uppervp == uppervp &&
UNIONTOV(un1)->v_mount == mp) {
@@ -506,7 +497,7 @@ loop:
* Another thread beat us, push back freshly
* allocated vnode and retry.
*/
- mutex_exit(&unheadlock[hash]);
+ mutex_exit(&uhash_lock);
ungetnewvnode(*vpp);
goto loop;
}
@@ -571,7 +562,7 @@ loop:
}
if (docache) {
- LIST_INSERT_HEAD(&unhead[hash], un, un_cache);
+ LIST_INSERT_HEAD(&uhashtbl[hash[0]], un, un_cache);
un->un_cflags |= UN_CACHED;
}
@@ -580,7 +571,7 @@ loop:
out:
if (docache)
- mutex_exit(&unheadlock[hash]);
+ mutex_exit(&uhash_lock);
return (error);
}
@@ -593,12 +584,12 @@ union_freevp(struct vnode *vp)
hash = UNION_HASH(un->un_uppervp, un->un_lowervp);
- mutex_enter(&unheadlock[hash]);
+ mutex_enter(&uhash_lock);
if (un->un_cflags & UN_CACHED) {
un->un_cflags &= ~UN_CACHED;
LIST_REMOVE(un, un_cache);
}
- mutex_exit(&unheadlock[hash]);
+ mutex_exit(&uhash_lock);
if (un->un_pvp != NULLVP)
vrele(un->un_pvp);
@@ -980,12 +971,12 @@ union_removed_upper(struct union_node *u
hash = UNION_HASH(un->un_uppervp, un->un_lowervp);
VOP_UNLOCK(vp);
- mutex_enter(&unheadlock[hash]);
+ mutex_enter(&uhash_lock);
if (un->un_cflags & UN_CACHED) {
un->un_cflags &= ~UN_CACHED;
LIST_REMOVE(un, un_cache);
}
- mutex_exit(&unheadlock[hash]);
+ mutex_exit(&uhash_lock);
}
#if 0
Index: src/sys/fs/union/union_vfsops.c
diff -u src/sys/fs/union/union_vfsops.c:1.65 src/sys/fs/union/union_vfsops.c:1.66
--- src/sys/fs/union/union_vfsops.c:1.65 Mon Nov 21 18:29:22 2011
+++ src/sys/fs/union/union_vfsops.c Wed Nov 23 19:39:11 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: union_vfsops.c,v 1.65 2011/11/21 18:29:22 hannken Exp $ */
+/* $NetBSD: union_vfsops.c,v 1.66 2011/11/23 19:39:11 hannken Exp $ */
/*
* Copyright (c) 1994 The Regents of the University of California.
@@ -77,7 +77,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.65 2011/11/21 18:29:22 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.66 2011/11/23 19:39:11 hannken Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -526,7 +526,7 @@ struct vfsops union_vfsops = {
(void *)eopnotsupp, /* vfs_fhtovp */
(void *)eopnotsupp, /* vfs_vptofh */
union_init,
- NULL, /* vfs_reinit */
+ union_reinit,
union_done,
NULL, /* vfs_mountroot */
(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
