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author | kib <kib@FreeBSD.org> | 2009-05-31 14:57:43 +0000 |
---|---|---|
committer | kib <kib@FreeBSD.org> | 2009-05-31 14:57:43 +0000 |
commit | 443228ae3b3ba01eab22a02b6017cb6d8af64c34 (patch) | |
tree | e967370fdcc8de8ab496321c7238fa38b602185d | |
parent | 0e1f2d3b3e4e791ad8dc69b5d3edfdbc1eca9771 (diff) | |
download | FreeBSD-src-443228ae3b3ba01eab22a02b6017cb6d8af64c34.zip FreeBSD-src-443228ae3b3ba01eab22a02b6017cb6d8af64c34.tar.gz |
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
-rw-r--r-- | sys/kern/vfs_cache.c | 160 | ||||
-rw-r--r-- | sys/sys/vnode.h | 1 |
2 files changed, 76 insertions, 85 deletions
diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c index 01c5e4c..cdfb308 100644 --- a/sys/kern/vfs_cache.c +++ b/sys/kern/vfs_cache.c @@ -206,7 +206,7 @@ SYSCTL_OPAQUE(_vfs_cache, OID_AUTO, nchstats, CTLFLAG_RD | CTLFLAG_MPSAFE, 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, struct vnode *vn, 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, char *buf, u_int *buflen) 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 vnode *vp, struct vnode *rdir, 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); } diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h index af1723f..3feae69 100644 --- a/sys/sys/vnode.h +++ b/sys/sys/vnode.h @@ -598,6 +598,7 @@ int insmntque1(struct vnode *vp, struct mount *mp, 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, |