File: [local] / sys / kern / vfs_cache.c (download)
Revision 1.1.1.1 (vendor branch), Tue Mar 4 16:15:04 2008 UTC (16 years, 4 months ago) by nbrk
Branch: OPENBSD_4_2_BASE, MAIN
CVS Tags: jornada-partial-support-wip, HEAD Changes since 1.1: +0 -0 lines
Import of OpenBSD 4.2 release kernel tree with initial code to support
Jornada 720/728, StrongARM 1110-based handheld PC.
At this point kernel roots on NFS and boots into vfs_mountroot() and traps.
What is supported:
- glass console, Jornada framebuffer (jfb) works in 16bpp direct color mode
(needs some palette tweaks for non black/white/blue colors, i think)
- saic, SA11x0 interrupt controller (needs cleanup)
- sacom, SA11x0 UART (supported only as boot console for now)
- SA11x0 GPIO controller fully supported (but can't handle multiple interrupt
handlers on one gpio pin)
- sassp, SSP port on SA11x0 that attaches spibus
- Jornada microcontroller (jmcu) to control kbd, battery, etc throught
the SPI bus (wskbd attaches on jmcu, but not tested)
- tod functions seem work
- initial code for SA-1111 (chip companion) : this is TODO
Next important steps, i think:
- gpio and intc on sa1111
- pcmcia support for sa11x0 (and sa1111 help logic)
- REAL root on nfs when we have PCMCIA support (we may use any of supported pccard NICs)
- root on wd0! (using already supported PCMCIA-ATA)
|
/* $OpenBSD: vfs_cache.c,v 1.25 2007/06/21 12:05:14 pedro Exp $ */
/* $NetBSD: vfs_cache.c,v 1.13 1996/02/04 02:18:09 christos Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_cache.c 8.3 (Berkeley) 8/22/94
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/hash.h>
/*
* TODO: namecache access should really be locked.
*/
/*
* Name caching works as follows:
*
* Names found by directory scans are retained in a cache
* for future reference. It is managed LRU, so frequently
* used names will hang around. Cache is indexed by hash value
* obtained from (vp, name) where vp refers to the directory
* containing name.
*
* For simplicity (and economy of storage), names longer than
* a maximum length of NCHNAMLEN are not cached; they occur
* infrequently in any case, and are almost never of interest.
*
* Upon reaching the last segment of a path, if the reference
* is for DELETE, or NOCACHE is set (rewrite), and the
* name is located in the cache, it will be dropped.
*/
/*
* Structures associated with name caching.
*/
LIST_HEAD(nchashhead, namecache) *nchashtbl;
u_long nchash; /* size of hash table - 1 */
long numcache; /* number of cache entries allocated */
TAILQ_HEAD(, namecache) nclruhead; /* LRU chain */
struct nchstats nchstats; /* cache effectiveness statistics */
LIST_HEAD(ncvhashhead, namecache) *ncvhashtbl;
u_long ncvhash; /* size of hash table - 1 */
#define NCHASH(dvp, cnp) \
hash32_buf(&(dvp)->v_id, sizeof((dvp)->v_id), (cnp)->cn_hash) & nchash
#define NCVHASH(vp) (vp)->v_id & ncvhash
int doingcache = 1; /* 1 => enable the cache */
struct pool nch_pool;
u_long nextvnodeid;
/*
* Look for a name in the cache. We don't do this if the segment name is
* long, simply so the cache can avoid holding long names (which would
* either waste space, or add greatly to the complexity).
*
* Lookup is called with ni_dvp pointing to the directory to search,
* ni_ptr pointing to the name of the entry being sought, ni_namelen
* tells the length of the name, and ni_hash contains a hash of
* the name. If the lookup succeeds, the vnode is returned in ni_vp
* and a status of 0 is returned. If the locking fails for whatever
* reason, the vnode is unlocked and the error is returned to caller.
* If the lookup determines that the name does not exist (negative caching),
* a status of ENOENT is returned. If the lookup fails, a status of -1
* is returned.
*/
int
cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
{
struct namecache *ncp;
struct nchashhead *ncpp;
struct vnode *vp;
struct proc *p = curproc;
u_long vpid;
int error;
*vpp = NULL;
if (!doingcache) {
cnp->cn_flags &= ~MAKEENTRY;
return (-1);
}
if (cnp->cn_namelen > NCHNAMLEN) {
nchstats.ncs_long++;
cnp->cn_flags &= ~MAKEENTRY;
return (-1);
}
ncpp = &nchashtbl[NCHASH(dvp, cnp)];
LIST_FOREACH(ncp, ncpp, nc_hash) {
if (ncp->nc_dvp == dvp &&
ncp->nc_dvpid == dvp->v_id &&
ncp->nc_nlen == cnp->cn_namelen &&
!memcmp(ncp->nc_name, cnp->cn_nameptr, (u_int)ncp->nc_nlen))
break;
}
if (ncp == NULL) {
nchstats.ncs_miss++;
return (-1);
}
if ((cnp->cn_flags & MAKEENTRY) == 0) {
nchstats.ncs_badhits++;
goto remove;
} else if (ncp->nc_vp == NULL) {
if (cnp->cn_nameiop != CREATE ||
(cnp->cn_flags & ISLASTCN) == 0) {
nchstats.ncs_neghits++;
/*
* Move this slot to end of LRU chain,
* if not already there.
*/
if (TAILQ_NEXT(ncp, nc_lru) != NULL) {
TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru);
}
return (ENOENT);
} else {
nchstats.ncs_badhits++;
goto remove;
}
} else if (ncp->nc_vpid != ncp->nc_vp->v_id) {
nchstats.ncs_falsehits++;
goto remove;
}
vp = ncp->nc_vp;
vpid = vp->v_id;
if (vp == dvp) { /* lookup on "." */
VREF(dvp);
error = 0;
} else if (cnp->cn_flags & ISDOTDOT) {
VOP_UNLOCK(dvp, 0, p);
cnp->cn_flags |= PDIRUNLOCK;
error = vget(vp, LK_EXCLUSIVE, p);
/*
* If the above vget() succeeded and both LOCKPARENT and
* ISLASTCN is set, lock the directory vnode as well.
*/
if (!error && (~cnp->cn_flags & (LOCKPARENT|ISLASTCN)) == 0) {
if ((error = vn_lock(dvp, LK_EXCLUSIVE, p)) != 0) {
vput(vp);
return (error);
}
cnp->cn_flags &= ~PDIRUNLOCK;
}
} else {
error = vget(vp, LK_EXCLUSIVE, p);
/*
* If the above vget() failed or either of LOCKPARENT or
* ISLASTCN is set, unlock the directory vnode.
*/
if (error || (~cnp->cn_flags & (LOCKPARENT|ISLASTCN)) != 0) {
VOP_UNLOCK(dvp, 0, p);
cnp->cn_flags |= PDIRUNLOCK;
}
}
/*
* Check that the lock succeeded, and that the capability number did
* not change while we were waiting for the lock.
*/
if (error || vpid != vp->v_id) {
if (!error) {
vput(vp);
nchstats.ncs_falsehits++;
} else
nchstats.ncs_badhits++;
/*
* The parent needs to be locked when we return to VOP_LOOKUP().
* The `.' case here should be extremely rare (if it can happen
* at all), so we don't bother optimizing out the unlock/relock.
*/
if (vp == dvp || error ||
(~cnp->cn_flags & (LOCKPARENT|ISLASTCN)) != 0) {
if ((error = vn_lock(dvp, LK_EXCLUSIVE, p)) != 0)
return (error);
cnp->cn_flags &= ~PDIRUNLOCK;
}
return (-1);
}
nchstats.ncs_goodhits++;
/*
* Move this slot to end of LRU chain, if not already there.
*/
if (TAILQ_NEXT(ncp, nc_lru) != NULL) {
TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru);
}
*vpp = vp;
return (0);
remove:
/*
* Last component and we are renaming or deleting,
* the cache entry is invalid, or otherwise don't
* want cache entry to exist.
*/
TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
LIST_REMOVE(ncp, nc_hash);
ncp->nc_hash.le_prev = NULL;
if (ncp->nc_vhash.le_prev != NULL) {
LIST_REMOVE(ncp, nc_vhash);
ncp->nc_vhash.le_prev = NULL;
}
pool_put(&nch_pool, ncp);
numcache--;
return (-1);
}
/*
* Scan cache looking for name of directory entry pointing at vp.
*
* Fill in dvpp.
*
* If bufp is non-NULL, also place the name in the buffer which starts
* at bufp, immediately before *bpp, and move bpp backwards to point
* at the start of it. (Yes, this is a little baroque, but it's done
* this way to cater to the whims of getcwd).
*
* Returns 0 on success, -1 on cache miss, positive errno on failure.
*
* TODO: should we return *dvpp locked?
*/
int
cache_revlookup(struct vnode *vp, struct vnode **dvpp, char **bpp, char *bufp)
{
struct namecache *ncp;
struct vnode *dvp;
struct ncvhashhead *nvcpp;
char *bp;
if (!doingcache)
goto out;
nvcpp = &ncvhashtbl[NCVHASH(vp)];
LIST_FOREACH(ncp, nvcpp, nc_vhash) {
if (ncp->nc_vp == vp &&
ncp->nc_vpid == vp->v_id &&
(dvp = ncp->nc_dvp) != NULL &&
/* avoid pesky '.' entries.. */
dvp != vp && ncp->nc_dvpid == dvp->v_id) {
#ifdef DIAGNOSTIC
if (ncp->nc_nlen == 1 &&
ncp->nc_name[0] == '.')
panic("cache_revlookup: found entry for .");
if (ncp->nc_nlen == 2 &&
ncp->nc_name[0] == '.' &&
ncp->nc_name[1] == '.')
panic("cache_revlookup: found entry for ..");
#endif
nchstats.ncs_revhits++;
if (bufp != NULL) {
bp = *bpp;
bp -= ncp->nc_nlen;
if (bp <= bufp) {
*dvpp = NULL;
return (ERANGE);
}
memcpy(bp, ncp->nc_name, ncp->nc_nlen);
*bpp = bp;
}
*dvpp = dvp;
/*
* XXX: Should we vget() here to have more
* consistent semantics with cache_lookup()?
*
* For MP safety it might be necessary to do
* this here, while also protecting hash
* tables themselves to provide some sort of
* sane inter locking.
*/
return (0);
}
}
nchstats.ncs_revmiss++;
out:
*dvpp = NULL;
return (-1);
}
/*
* Add an entry to the cache
*/
void
cache_enter(struct vnode *dvp, struct vnode *vp, struct componentname *cnp)
{
struct namecache *ncp;
struct nchashhead *ncpp;
struct ncvhashhead *nvcpp;
if (!doingcache || cnp->cn_namelen > NCHNAMLEN)
return;
/*
* Free the cache slot at head of lru chain.
*/
if (numcache < desiredvnodes) {
ncp = pool_get(&nch_pool, PR_WAITOK);
bzero((char *)ncp, sizeof *ncp);
numcache++;
} else if ((ncp = TAILQ_FIRST(&nclruhead)) != NULL) {
TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
if (ncp->nc_hash.le_prev != NULL) {
LIST_REMOVE(ncp, nc_hash);
ncp->nc_hash.le_prev = NULL;
}
if (ncp->nc_vhash.le_prev != NULL) {
LIST_REMOVE(ncp, nc_vhash);
ncp->nc_vhash.le_prev = NULL;
}
} else
return;
/* grab the vnode we just found */
ncp->nc_vp = vp;
if (vp)
ncp->nc_vpid = vp->v_id;
/* fill in cache info */
ncp->nc_dvp = dvp;
ncp->nc_dvpid = dvp->v_id;
ncp->nc_nlen = cnp->cn_namelen;
bcopy(cnp->cn_nameptr, ncp->nc_name, (unsigned)ncp->nc_nlen);
TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru);
ncpp = &nchashtbl[NCHASH(dvp, cnp)];
LIST_INSERT_HEAD(ncpp, ncp, nc_hash);
/*
* Create reverse-cache entries (used in getcwd) for
* directories.
*/
ncp->nc_vhash.le_prev = NULL;
ncp->nc_vhash.le_next = NULL;
if (vp && vp != dvp && vp->v_type == VDIR &&
(ncp->nc_nlen > 2 ||
(ncp->nc_nlen > 1 && ncp->nc_name[1] != '.') ||
(ncp->nc_nlen > 0 && ncp->nc_name[0] != '.'))) {
nvcpp = &ncvhashtbl[NCVHASH(vp)];
LIST_INSERT_HEAD(nvcpp, ncp, nc_vhash);
}
}
/*
* Name cache initialization, from vfs_init() when we are booting
*/
void
nchinit(void)
{
TAILQ_INIT(&nclruhead);
nchashtbl = hashinit(desiredvnodes, M_CACHE, M_WAITOK, &nchash);
ncvhashtbl = hashinit(desiredvnodes/8, M_CACHE, M_WAITOK, &ncvhash);
pool_init(&nch_pool, sizeof(struct namecache), 0, 0, 0, "nchpl",
&pool_allocator_nointr);
}
/*
* Cache flush, a particular vnode; called when a vnode is renamed to
* hide entries that would now be invalid
*/
void
cache_purge(struct vnode *vp)
{
struct namecache *ncp;
struct nchashhead *ncpp;
vp->v_id = ++nextvnodeid;
if (nextvnodeid != 0)
return;
for (ncpp = &nchashtbl[nchash]; ncpp >= nchashtbl; ncpp--) {
LIST_FOREACH(ncp, ncpp, nc_hash) {
ncp->nc_vpid = 0;
ncp->nc_dvpid = 0;
}
}
vp->v_id = ++nextvnodeid;
}
/*
* Cache flush, a whole filesystem; called when filesys is umounted to
* remove entries that would now be invalid
*/
void
cache_purgevfs(struct mount *mp)
{
struct namecache *ncp, *nxtcp;
for (ncp = TAILQ_FIRST(&nclruhead); ncp != TAILQ_END(&nclruhead);
ncp = nxtcp) {
nxtcp = TAILQ_NEXT(ncp, nc_lru);
if (ncp->nc_dvp == NULL || ncp->nc_dvp->v_mount != mp)
continue;
/* free the resources we had */
ncp->nc_vp = NULL;
ncp->nc_dvp = NULL;
TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
if (ncp->nc_hash.le_prev != NULL) {
LIST_REMOVE(ncp, nc_hash);
ncp->nc_hash.le_prev = NULL;
}
if (ncp->nc_vhash.le_prev != NULL) {
LIST_REMOVE(ncp, nc_vhash);
ncp->nc_vhash.le_prev = NULL;
}
pool_put(&nch_pool, ncp);
numcache--;
}
}