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-rw-r--r--sys/kern/vfs_cache.c155
1 files changed, 142 insertions, 13 deletions
diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c
index 7c7afa3..860db8d 100644
--- a/sys/kern/vfs_cache.c
+++ b/sys/kern/vfs_cache.c
@@ -45,7 +45,25 @@
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/malloc.h>
+#include <sys/sysproto.h>
+#include <sys/proc.h>
+#include <sys/filedesc.h>
+/*
+ * This structure describes the elements in the cache of recent
+ * names looked up by namei.
+ */
+
+struct namecache {
+ LIST_ENTRY(namecache) nc_hash; /* hash chain */
+ LIST_ENTRY(namecache) nc_src; /* source vnode list */
+ TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */
+ struct vnode *nc_dvp; /* vnode of parent of name */
+ struct vnode *nc_vp; /* vnode the name refers to */
+ u_char nc_flag; /* flag bits */
+ u_char nc_nlen; /* length of name */
+ char nc_name[0]; /* segment name */
+};
/*
* Name caching works as follows:
@@ -67,8 +85,8 @@
/*
* Structures associated with name cacheing.
*/
-#define NCHHASH(dvp, cnp) \
- (&nchashtbl[((dvp)->v_id + (cnp)->cn_hash) & nchash])
+#define NCHHASH(dvp, hash) \
+ (&nchashtbl[((dvp)->v_id + (hash)) & nchash])
static LIST_HEAD(nchashhead, namecache) *nchashtbl; /* Hash Table */
static TAILQ_HEAD(, namecache) ncneg; /* Hash Table */
static u_long nchash; /* size of hash table */
@@ -108,6 +126,8 @@ static u_long numneghits; STATNODE(CTLFLAG_RD, numneghits, &numneghits);
static void cache_zap __P((struct namecache *ncp));
+MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
+
/*
* Flags in namecache.nc_flag
*/
@@ -131,7 +151,7 @@ cache_zap(ncp)
numneg--;
}
numcache--;
- free(ncp, M_CACHE);
+ free(ncp, M_VFSCACHE);
}
/*
@@ -155,7 +175,10 @@ cache_lookup(dvp, vpp, cnp)
struct vnode **vpp;
struct componentname *cnp;
{
- register struct namecache *ncp;
+ struct namecache *ncp;
+ u_long hash;
+ u_char *cp;
+ int len;
if (!doingcache) {
cnp->cn_flags &= ~MAKEENTRY;
@@ -182,7 +205,11 @@ cache_lookup(dvp, vpp, cnp)
}
}
- LIST_FOREACH(ncp, (NCHHASH(dvp, cnp)), nc_hash) {
+ hash = 0;
+ len = cnp->cn_namelen;
+ for (cp = cnp->cn_nameptr; len; len--, cp++)
+ hash += *cp;
+ LIST_FOREACH(ncp, (NCHHASH(dvp, hash)), nc_hash) {
numchecks++;
if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
!bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
@@ -246,8 +273,11 @@ cache_enter(dvp, vp, cnp)
struct vnode *vp;
struct componentname *cnp;
{
- register struct namecache *ncp;
- register struct nchashhead *ncpp;
+ struct namecache *ncp;
+ struct nchashhead *ncpp;
+ u_long hash;
+ u_char *cp, *dp;
+ int len;
if (!doingcache)
return;
@@ -269,7 +299,7 @@ cache_enter(dvp, vp, cnp)
}
ncp = (struct namecache *)
- malloc(sizeof *ncp + cnp->cn_namelen, M_CACHE, M_WAITOK);
+ malloc(sizeof *ncp + cnp->cn_namelen, M_VFSCACHE, M_WAITOK);
bzero((char *)ncp, sizeof *ncp);
numcache++;
if (!vp) {
@@ -288,9 +318,12 @@ cache_enter(dvp, vp, cnp)
*/
ncp->nc_vp = vp;
ncp->nc_dvp = dvp;
- ncp->nc_nlen = cnp->cn_namelen;
- bcopy(cnp->cn_nameptr, ncp->nc_name, ncp->nc_nlen);
- ncpp = NCHHASH(dvp, cnp);
+ len = ncp->nc_nlen = cnp->cn_namelen;
+ hash = 0;
+ dp = ncp->nc_name;
+ for (cp = cnp->cn_nameptr; len; len--, cp++, dp++)
+ hash += (*dp = *cp);
+ ncpp = NCHHASH(dvp, hash);
LIST_INSERT_HEAD(ncpp, ncp, nc_hash);
if (LIST_EMPTY(&dvp->v_cache_src))
vhold(dvp);
@@ -300,7 +333,7 @@ cache_enter(dvp, vp, cnp)
} else {
TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
}
- if (numneg*ncnegfactor > numcache) {
+ if (numneg * ncnegfactor > numcache) {
ncp = TAILQ_FIRST(&ncneg);
cache_zap(ncp);
}
@@ -314,7 +347,7 @@ nchinit()
{
TAILQ_INIT(&ncneg);
- nchashtbl = hashinit(desiredvnodes*2, M_CACHE, &nchash);
+ nchashtbl = hashinit(desiredvnodes*2, M_VFSCACHE, &nchash);
}
/*
@@ -456,3 +489,99 @@ vfs_cache_lookup(ap)
return (error);
return (VOP_CACHEDLOOKUP(ap->a_dvp, ap->a_vpp, ap->a_cnp));
}
+
+
+#ifndef _SYS_SYSPROTO_H_
+struct __getcwd_args {
+ u_char *buf;
+ u_int buflen;
+};
+#endif
+
+#define STATNODE(mode, name, var) \
+ SYSCTL_INT(_vfs_cache, OID_AUTO, name, mode, var, 0, "");
+
+static int disablecwd;
+SYSCTL_INT(_debug, OID_AUTO, disablecwd, CTLFLAG_RW, &disablecwd, 0, "");
+
+static u_long numcwdcalls; STATNODE(CTLFLAG_RD, numcwdcalls, &numcwdcalls);
+static u_long numcwdfail1; STATNODE(CTLFLAG_RD, numcwdfail1, &numcwdfail1);
+static u_long numcwdfail2; STATNODE(CTLFLAG_RD, numcwdfail2, &numcwdfail2);
+static u_long numcwdfail3; STATNODE(CTLFLAG_RD, numcwdfail3, &numcwdfail3);
+static u_long numcwdfail4; STATNODE(CTLFLAG_RD, numcwdfail4, &numcwdfail4);
+static u_long numcwdfound; STATNODE(CTLFLAG_RD, numcwdfound, &numcwdfound);
+int
+__getcwd(p, uap)
+ struct proc *p;
+ struct __getcwd_args *uap;
+{
+ char *bp, *buf;
+ int error, i, slash_prefixed;
+ struct filedesc *fdp;
+ struct namecache *ncp;
+ struct vnode *vp;
+
+ numcwdcalls++;
+ if (disablecwd)
+ return (ENODEV);
+ if (uap->buflen < 2)
+ return (EINVAL);
+ if (uap->buflen > MAXPATHLEN)
+ uap->buflen = MAXPATHLEN;
+ buf = bp = malloc(uap->buflen, M_TEMP, M_WAITOK);
+ bp += uap->buflen - 1;
+ *bp = '\0';
+ fdp = p->p_fd;
+ slash_prefixed = 0;
+ for (vp = fdp->fd_cdir; vp != fdp->fd_rdir && vp != rootvnode;) {
+ if (vp->v_flag & VROOT) {
+ vp = vp->v_mount->mnt_vnodecovered;
+ continue;
+ }
+ if (vp->v_dd->v_id != vp->v_ddid) {
+ numcwdfail1++;
+ free(buf, M_TEMP);
+ return (ENOTDIR);
+ }
+ ncp = TAILQ_FIRST(&vp->v_cache_dst);
+ if (!ncp) {
+ numcwdfail2++;
+ free(buf, M_TEMP);
+ return (ENOENT);
+ }
+ if (ncp->nc_dvp != vp->v_dd) {
+ numcwdfail3++;
+ free(buf, M_TEMP);
+ return (EBADF);
+ }
+ for (i = ncp->nc_nlen - 1; i >= 0; i--) {
+ if (bp == buf) {
+ numcwdfail4++;
+ free(buf, M_TEMP);
+ return (ENOMEM);
+ }
+ *--bp = ncp->nc_name[i];
+ }
+ if (bp == buf) {
+ numcwdfail4++;
+ free(buf, M_TEMP);
+ return (ENOMEM);
+ }
+ *--bp = '/';
+ slash_prefixed = 1;
+ vp = vp->v_dd;
+ }
+ if (!slash_prefixed) {
+ if (bp == buf) {
+ numcwdfail4++;
+ free(buf, M_TEMP);
+ return (ENOMEM);
+ }
+ *--bp = '/';
+ }
+ numcwdfound++;
+ error = copyout(bp, uap->buf, strlen(bp) + 1);
+ free(buf, M_TEMP);
+ return (error);
+}
+
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