svn commit: r193174 - in head/sys: kern sys
Konstantin Belousov
kib at FreeBSD.org
Sun May 31 14:57:45 UTC 2009
Author: kib
Date: Sun May 31 14:57:43 2009
New Revision: 193174
URL: http://svn.freebsd.org/changeset/base/193174
Log:
Eliminate code duplication in vn_fullpath1() around the cache lookups
and calls to vn_vptocnp() by moving more of the common code to
vn_vptocnp(). Rename vn_vptocnp() to vn_vptocnp_locked() to signify that
cache is locked around the call.
Do not track buffer position by both the pointer and offset, use only
buflen to record the start of the free space.
Export vn_vptocnp() for external consumers as a wrapper around
vn_vptocnp_locked() that locks the cache and handles hold counts.
Tested by: pho
Modified:
head/sys/kern/vfs_cache.c
head/sys/sys/vnode.h
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Sun May 31 14:54:20 2009 (r193173)
+++ head/sys/kern/vfs_cache.c Sun May 31 14:57:43 2009 (r193174)
@@ -206,7 +206,7 @@ SYSCTL_OPAQUE(_vfs_cache, OID_AUTO, nchs
static void cache_zap(struct namecache *ncp);
-static int vn_vptocnp(struct vnode **vp, char **bp, char *buf, u_int *buflen);
+static int vn_vptocnp_locked(struct vnode **vp, char *buf, u_int *buflen);
static int vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir,
char *buf, char **retbuf, u_int buflen);
@@ -1036,12 +1036,55 @@ vn_fullpath_global(struct thread *td, st
return (error);
}
+int
+vn_vptocnp(struct vnode **vp, char *buf, u_int *buflen)
+{
+ int error;
+
+ CACHE_RLOCK();
+ error = vn_vptocnp_locked(vp, buf, buflen);
+ if (error == 0) {
+ /*
+ * vn_vptocnp_locked() dropped hold acquired by
+ * VOP_VPTOCNP immediately after locking the
+ * cache. Since we are going to drop the cache rlock,
+ * re-hold the result.
+ */
+ vhold(*vp);
+ CACHE_RUNLOCK();
+ }
+ return (error);
+}
+
static int
-vn_vptocnp(struct vnode **vp, char **bp, char *buf, u_int *buflen)
+vn_vptocnp_locked(struct vnode **vp, char *buf, u_int *buflen)
{
struct vnode *dvp;
+ struct namecache *ncp;
int error, vfslocked;
+ TAILQ_FOREACH(ncp, &((*vp)->v_cache_dst), nc_dst) {
+ if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
+ break;
+ }
+ if (ncp != NULL) {
+ if (*buflen < ncp->nc_nlen) {
+ CACHE_RUNLOCK();
+ numfullpathfail4++;
+ error = ENOMEM;
+ SDT_PROBE(vfs, namecache, fullpath, return, error,
+ startvp, NULL, 0, 0);
+ return (error);
+ }
+ *buflen -= ncp->nc_nlen;
+ memcpy(buf + *buflen, ncp->nc_name, ncp->nc_nlen);
+ SDT_PROBE(vfs, namecache, fullpath, hit, ncp->nc_dvp,
+ ncp->nc_name, vp, 0, 0);
+ *vp = ncp->nc_dvp;
+ return (0);
+ }
+ SDT_PROBE(vfs, namecache, fullpath, miss, vp, 0, 0, 0, 0);
+
vhold(*vp);
CACHE_RUNLOCK();
vfslocked = VFS_LOCK_GIANT((*vp)->v_mount);
@@ -1052,16 +1095,21 @@ vn_vptocnp(struct vnode **vp, char **bp,
VFS_UNLOCK_GIANT(vfslocked);
if (error) {
numfullpathfail2++;
+ SDT_PROBE(vfs, namecache, fullpath, return, error, startvp,
+ NULL, 0, 0);
return (error);
}
- *bp = buf + *buflen;
+
*vp = dvp;
CACHE_RLOCK();
if ((*vp)->v_iflag & VI_DOOMED) {
/* forced unmount */
CACHE_RUNLOCK();
vdrop(*vp);
- return (ENOENT);
+ error = ENOENT;
+ SDT_PROBE(vfs, namecache, fullpath, return, error, startvp,
+ NULL, 0, 0);
+ return (error);
}
vdrop(*vp);
@@ -1075,59 +1123,26 @@ static int
vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir,
char *buf, char **retbuf, u_int buflen)
{
- char *bp;
- int error, i, slash_prefixed;
- struct namecache *ncp;
+ int error, slash_prefixed;
#ifdef KDTRACE_HOOKS
struct vnode *startvp = vp;
#endif
buflen--;
- bp = buf + buflen;
- *bp = '\0';
+ buf[buflen] = '\0';
error = 0;
slash_prefixed = 0;
SDT_PROBE(vfs, namecache, fullpath, entry, vp, 0, 0, 0, 0);
- CACHE_RLOCK();
numfullpathcalls++;
+ CACHE_RLOCK();
if (vp->v_type != VDIR) {
- ncp = TAILQ_FIRST(&vp->v_cache_dst);
- if (ncp != NULL) {
- buflen -= ncp->nc_nlen;
- for (i = ncp->nc_nlen - 1; i >= 0 && bp != buf; i--)
- *--bp = ncp->nc_name[i];
- if (bp == buf) {
- numfullpathfail4++;
- CACHE_RUNLOCK();
- error = ENOMEM;
- SDT_PROBE(vfs, namecache, fullpath, return,
- error, startvp, NULL, 0, 0);
- return (error);
- }
- SDT_PROBE(vfs, namecache, fullpath, hit, ncp->nc_dvp,
- ncp->nc_name, vp, 0, 0);
- vp = ncp->nc_dvp;
- } else {
- SDT_PROBE(vfs, namecache, fullpath, miss, vp, 0, 0,
- 0, 0);
- error = vn_vptocnp(&vp, &bp, buf, &buflen);
- if (error) {
- SDT_PROBE(vfs, namecache, fullpath, return,
- error, startvp, NULL, 0, 0);
- return (error);
- }
- }
- if (buflen <= 0) {
- numfullpathfail4++;
- CACHE_RUNLOCK();
- error = ENOMEM;
- SDT_PROBE(vfs, namecache, fullpath, return, error,
- startvp, NULL, 0, 0);
+ error = vn_vptocnp_locked(&vp, buf, &buflen);
+ if (error)
return (error);
- }
- *--bp = '/';
- buflen--;
+ if (buflen == 0)
+ return (ENOMEM);
+ buf[--buflen] = '/';
slash_prefixed = 1;
}
while (vp != rdir && vp != rootvnode) {
@@ -1141,64 +1156,39 @@ vn_fullpath1(struct thread *td, struct v
continue;
}
if (vp->v_type != VDIR) {
- numfullpathfail1++;
CACHE_RUNLOCK();
+ numfullpathfail1++;
error = ENOTDIR;
break;
}
- TAILQ_FOREACH(ncp, &vp->v_cache_dst, nc_dst)
- if ((ncp->nc_flag & NCF_ISDOTDOT) == 0)
- break;
- if (ncp != NULL) {
- buflen -= ncp->nc_nlen;
- for (i = ncp->nc_nlen - 1; i >= 0 && bp != buf; i--)
- *--bp = ncp->nc_name[i];
- if (bp == buf) {
- numfullpathfail4++;
- CACHE_RUNLOCK();
- error = ENOMEM;
- break;
- }
- SDT_PROBE(vfs, namecache, fullpath, hit, ncp->nc_dvp,
- ncp->nc_name, vp, 0, 0);
- vp = ncp->nc_dvp;
- } else {
- SDT_PROBE(vfs, namecache, fullpath, miss, vp, 0, 0,
- 0, 0);
- error = vn_vptocnp(&vp, &bp, buf, &buflen);
- if (error)
- break;
- }
- if (buflen <= 0) {
- numfullpathfail4++;
- CACHE_RUNLOCK();
+ error = vn_vptocnp_locked(&vp, buf, &buflen);
+ if (error)
+ break;
+ if (buflen == 0) {
error = ENOMEM;
break;
}
- *--bp = '/';
- buflen--;
+ buf[--buflen] = '/';
slash_prefixed = 1;
}
- if (error) {
- SDT_PROBE(vfs, namecache, fullpath, return, error, startvp,
- NULL, 0, 0);
+ if (error)
return (error);
- }
if (!slash_prefixed) {
- if (bp == buf) {
- numfullpathfail4++;
+ if (buflen == 0) {
CACHE_RUNLOCK();
+ numfullpathfail4++;
SDT_PROBE(vfs, namecache, fullpath, return, 0,
- startvp, bp, 0, 0);
+ startvp, fullpath, 0, 0);
return (ENOMEM);
- } else
- *--bp = '/';
+ }
+ buf[--buflen] = '/';
}
numfullpathfound++;
CACHE_RUNLOCK();
- SDT_PROBE(vfs, namecache, fullpath, return, 0, startvp, bp, 0, 0);
- *retbuf = bp;
+ SDT_PROBE(vfs, namecache, fullpath, return, 0, startvp, buf + *buflen,
+ 0, 0);
+ *retbuf = buf + buflen;
return (0);
}
Modified: head/sys/sys/vnode.h
==============================================================================
--- head/sys/sys/vnode.h Sun May 31 14:54:20 2009 (r193173)
+++ head/sys/sys/vnode.h Sun May 31 14:57:43 2009 (r193174)
@@ -598,6 +598,7 @@ int insmntque1(struct vnode *vp, struct
int insmntque(struct vnode *vp, struct mount *mp);
u_quad_t init_va_filerev(void);
int speedup_syncer(void);
+int vn_vptocnp(struct vnode **vp, char *buf, u_int *buflen);
#define textvp_fullpath(p, rb, rfb) \
vn_fullpath(FIRST_THREAD_IN_PROC(p), (p)->p_textvp, rb, rfb)
int vn_fullpath(struct thread *td, struct vnode *vn,
More information about the svn-src-all
mailing list