/*
- * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License"). You may not use this file except in compliance with the
- * License. Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
*
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
*
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
*
* @(#)vfs_cache.c 8.5 (Berkeley) 3/22/95
*/
+/*
+ * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
+ * support for mandatory and extensible security protections. This notice
+ * is included in support of clause 2.2 (b) of the Apple Public License,
+ * Version 2.0.
+ */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
-#include <sys/mount.h>
-#include <sys/vnode.h>
+#include <sys/mount_internal.h>
+#include <sys/vnode_internal.h>
#include <sys/namei.h>
#include <sys/errno.h>
#include <sys/malloc.h>
+#include <sys/kauth.h>
+#include <sys/user.h>
+#include <sys/paths.h>
+
+#if CONFIG_MACF
+#include <security/mac_framework.h>
+#endif
/*
* Name caching works as follows:
* If it is a "negative" entry, (i.e. for a name that is known NOT to
* exist) the vnode pointer will be NULL.
*
- * 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 cacheing.
*/
-#define NCHHASH(dvp, hash_val) \
- (&nchashtbl[((u_long)(dvp) ^ ((dvp)->v_id ^ (hash_val))) & nchash])
+
LIST_HEAD(nchashhead, namecache) *nchashtbl; /* Hash Table */
+u_long nchashmask;
u_long nchash; /* size of hash table - 1 */
long numcache; /* number of cache entries allocated */
-TAILQ_HEAD(, namecache) nclruhead; /* LRU chain */
+int desiredNodes;
+int desiredNegNodes;
+int ncs_negtotal;
+int nc_disabled = 0;
+TAILQ_HEAD(, namecache) nchead; /* chain of all name cache entries */
+TAILQ_HEAD(, namecache) neghead; /* chain of only negative cache entries */
+
+
+#if COLLECT_STATS
+
struct nchstats nchstats; /* cache effectiveness statistics */
-u_long nextvnodeid = 0;
-int doingcache = 1; /* 1 => enable the cache */
+#define NCHSTAT(v) { \
+ nchstats.v++; \
+}
+#define NAME_CACHE_LOCK() name_cache_lock()
+#define NAME_CACHE_UNLOCK() name_cache_unlock()
+#define NAME_CACHE_LOCK_SHARED() name_cache_lock()
+
+#else
+
+#define NCHSTAT(v)
+#define NAME_CACHE_LOCK() name_cache_lock()
+#define NAME_CACHE_UNLOCK() name_cache_unlock()
+#define NAME_CACHE_LOCK_SHARED() name_cache_lock_shared()
+
+#endif
+
+
+/* vars for name cache list lock */
+lck_grp_t * namecache_lck_grp;
+lck_grp_attr_t * namecache_lck_grp_attr;
+lck_attr_t * namecache_lck_attr;
+
+lck_grp_t * strcache_lck_grp;
+lck_grp_attr_t * strcache_lck_grp_attr;
+lck_attr_t * strcache_lck_attr;
+
+lck_rw_t * namecache_rw_lock;
+lck_rw_t * strtable_rw_lock;
+
+#define NUM_STRCACHE_LOCKS 1024
+
+lck_mtx_t strcache_mtx_locks[NUM_STRCACHE_LOCKS];
+
+
+static vnode_t cache_lookup_locked(vnode_t dvp, struct componentname *cnp);
+static const char *add_name_internal(const char *, uint32_t, u_int, boolean_t, u_int);
+static void init_string_table(void) __attribute__((section("__TEXT, initcode")));
+static void cache_delete(struct namecache *, int);
+static void cache_enter_locked(vnode_t dvp, vnode_t vp, struct componentname *cnp, const char *strname);
+
+#ifdef DUMP_STRING_TABLE
/*
- * Delete an entry from its hash list and move it to the front
- * of the LRU list for immediate reuse.
+ * Internal dump function used for debugging
+ */
+void dump_string_table(void);
+#endif /* DUMP_STRING_TABLE */
+
+static void init_crc32(void) __attribute__((section("__TEXT, initcode")));
+static unsigned int crc32tab[256];
+
+
+#define NCHHASH(dvp, hash_val) \
+ (&nchashtbl[(dvp->v_id ^ (hash_val)) & nchashmask])
+
+
+
+/*
+ * This function builds the path to a filename in "buff". The
+ * length of the buffer *INCLUDING* the trailing zero byte is
+ * returned in outlen. NOTE: the length includes the trailing
+ * zero byte and thus the length is one greater than what strlen
+ * would return. This is important and lots of code elsewhere
+ * in the kernel assumes this behavior.
+ *
+ * This function can call vnop in file system if the parent vnode
+ * does not exist or when called for hardlinks via volfs path.
+ * If BUILDPATH_NO_FS_ENTER is set in flags, it only uses values present
+ * in the name cache and does not enter the file system.
*
- * NOTE: THESE MACROS CAN BLOCK (in the call to remove_name())
- * SO BE CAREFUL IF YOU HOLD POINTERS TO nclruhead OR
- * nchashtbl.
+ * passed in vp must have a valid io_count reference
*/
-#if DIAGNOSTIC
-#define PURGE(ncp) { \
- if (ncp->nc_hash.le_prev == 0) \
- panic("namecache purge le_prev"); \
- if (ncp->nc_hash.le_next == ncp) \
- panic("namecache purge le_next"); \
- LIST_REMOVE(ncp, nc_hash); \
- ncp->nc_hash.le_prev = 0; \
- TAILQ_REMOVE(&nclruhead, ncp, nc_lru); \
- TAILQ_INSERT_HEAD(&nclruhead, ncp, nc_lru); \
- /* this has to come last because it could block */ \
- remove_name(ncp->nc_name); \
- ncp->nc_name = NULL; \
+int
+build_path(vnode_t first_vp, char *buff, int buflen, int *outlen, int flags, vfs_context_t ctx)
+{
+ vnode_t vp, tvp;
+ vnode_t vp_with_iocount;
+ vnode_t proc_root_dir_vp;
+ char *end;
+ const char *str;
+ int len;
+ int ret = 0;
+ int fixhardlink;
+
+ if (first_vp == NULLVP)
+ return (EINVAL);
+
+ /*
+ * Grab the process fd so we can evaluate fd_rdir.
+ */
+ if (vfs_context_proc(ctx)->p_fd)
+ proc_root_dir_vp = vfs_context_proc(ctx)->p_fd->fd_rdir;
+ else
+ proc_root_dir_vp = NULL;
+
+ vp_with_iocount = NULLVP;
+again:
+ vp = first_vp;
+
+ end = &buff[buflen-1];
+ *end = '\0';
+
+ /*
+ * holding the NAME_CACHE_LOCK in shared mode is
+ * sufficient to stabilize both the vp->v_parent chain
+ * and the 'vp->v_mount->mnt_vnodecovered' chain
+ *
+ * if we need to drop this lock, we must first grab the v_id
+ * from the vnode we're currently working with... if that
+ * vnode doesn't already have an io_count reference (the vp
+ * passed in comes with one), we must grab a reference
+ * after we drop the NAME_CACHE_LOCK via vnode_getwithvid...
+ * deadlocks may result if you call vnode_get while holding
+ * the NAME_CACHE_LOCK... we lazily release the reference
+ * we pick up the next time we encounter a need to drop
+ * the NAME_CACHE_LOCK or before we return from this routine
+ */
+ NAME_CACHE_LOCK_SHARED();
+
+ /*
+ * Check if this is the root of a file system.
+ */
+ while (vp && vp->v_flag & VROOT) {
+ if (vp->v_mount == NULL) {
+ ret = EINVAL;
+ goto out_unlock;
+ }
+ if ((vp->v_mount->mnt_flag & MNT_ROOTFS) || (vp == proc_root_dir_vp)) {
+ /*
+ * It's the root of the root file system, so it's
+ * just "/".
+ */
+ *--end = '/';
+
+ goto out_unlock;
+ } else {
+ vp = vp->v_mount->mnt_vnodecovered;
+ }
+ }
+
+ while ((vp != NULLVP) && (vp->v_parent != vp)) {
+ int vid;
+
+ /*
+ * For hardlinks the v_name may be stale, so if its OK
+ * to enter a file system, ask the file system for the
+ * name and parent (below).
+ */
+ fixhardlink = (vp->v_flag & VISHARDLINK) &&
+ (vp->v_mount->mnt_kern_flag & MNTK_PATH_FROM_ID) &&
+ !(flags & BUILDPATH_NO_FS_ENTER);
+
+ if (!fixhardlink) {
+ str = vp->v_name;
+
+ if (str == NULL || *str == '\0') {
+ if (vp->v_parent != NULL)
+ ret = EINVAL;
+ else
+ ret = ENOENT;
+ goto out_unlock;
+ }
+ len = strlen(str);
+ /*
+ * Check that there's enough space (including space for the '/')
+ */
+ if ((end - buff) < (len + 1)) {
+ ret = ENOSPC;
+ goto out_unlock;
+ }
+ /*
+ * Copy the name backwards.
+ */
+ str += len;
+
+ for (; len > 0; len--)
+ *--end = *--str;
+ /*
+ * Add a path separator.
+ */
+ *--end = '/';
+ }
+
+ /*
+ * Walk up the parent chain.
+ */
+ if (((vp->v_parent != NULLVP) && !fixhardlink) ||
+ (flags & BUILDPATH_NO_FS_ENTER)) {
+ /*
+ * In this if () block we are not allowed to enter the filesystem
+ * to conclusively get the most accurate parent identifier.
+ * As a result, if 'vp' does not identify '/' and it
+ * does not have a valid v_parent, then error out
+ * and disallow further path construction
+ */
+ if ((vp->v_parent == NULLVP) && (rootvnode != vp)) {
+ /* Only '/' is allowed to have a NULL parent pointer */
+ ret = EINVAL;
+
+ /* The code below will exit early if 'tvp = vp' == NULL */
+ }
+
+ vp = vp->v_parent;
+
+ /*
+ * if the vnode we have in hand isn't a directory and it
+ * has a v_parent, then we started with the resource fork
+ * so skip up to avoid getting a duplicate copy of the
+ * file name in the path.
+ */
+ if (vp && !vnode_isdir(vp) && vp->v_parent)
+ vp = vp->v_parent;
+ } else {
+ /*
+ * No parent, go get it if supported.
+ */
+ struct vnode_attr va;
+ vnode_t dvp;
+
+ /*
+ * Make sure file system supports obtaining a path from id.
+ */
+ if (!(vp->v_mount->mnt_kern_flag & MNTK_PATH_FROM_ID)) {
+ ret = ENOENT;
+ goto out_unlock;
+ }
+ vid = vp->v_id;
+
+ NAME_CACHE_UNLOCK();
+
+ if (vp != first_vp && vp != vp_with_iocount) {
+ if (vp_with_iocount) {
+ vnode_put(vp_with_iocount);
+ vp_with_iocount = NULLVP;
+ }
+ if (vnode_getwithvid(vp, vid))
+ goto again;
+ vp_with_iocount = vp;
+ }
+ VATTR_INIT(&va);
+ VATTR_WANTED(&va, va_parentid);
+
+ if (fixhardlink) {
+ VATTR_WANTED(&va, va_name);
+ MALLOC_ZONE(va.va_name, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
+ } else {
+ va.va_name = NULL;
+ }
+ /*
+ * Ask the file system for its parent id and for its name (optional).
+ */
+ ret = vnode_getattr(vp, &va, ctx);
+
+ if (fixhardlink) {
+ if ((ret == 0) && (VATTR_IS_SUPPORTED(&va, va_name))) {
+ str = va.va_name;
+ vnode_update_identity(vp, NULL, str, strlen(str), 0, VNODE_UPDATE_NAME);
+ } else if (vp->v_name) {
+ str = vp->v_name;
+ ret = 0;
+ } else {
+ ret = ENOENT;
+ goto bad_news;
+ }
+ len = strlen(str);
+
+ /*
+ * Check that there's enough space.
+ */
+ if ((end - buff) < (len + 1)) {
+ ret = ENOSPC;
+ } else {
+ /* Copy the name backwards. */
+ str += len;
+
+ for (; len > 0; len--) {
+ *--end = *--str;
+ }
+ /*
+ * Add a path separator.
+ */
+ *--end = '/';
+ }
+bad_news:
+ FREE_ZONE(va.va_name, MAXPATHLEN, M_NAMEI);
+ }
+ if (ret || !VATTR_IS_SUPPORTED(&va, va_parentid)) {
+ ret = ENOENT;
+ goto out;
+ }
+ /*
+ * Ask the file system for the parent vnode.
+ */
+ if ((ret = VFS_VGET(vp->v_mount, (ino64_t)va.va_parentid, &dvp, ctx)))
+ goto out;
+
+ if (!fixhardlink && (vp->v_parent != dvp))
+ vnode_update_identity(vp, dvp, NULL, 0, 0, VNODE_UPDATE_PARENT);
+
+ if (vp_with_iocount)
+ vnode_put(vp_with_iocount);
+ vp = dvp;
+ vp_with_iocount = vp;
+
+ NAME_CACHE_LOCK_SHARED();
+
+ /*
+ * if the vnode we have in hand isn't a directory and it
+ * has a v_parent, then we started with the resource fork
+ * so skip up to avoid getting a duplicate copy of the
+ * file name in the path.
+ */
+ if (vp && !vnode_isdir(vp) && vp->v_parent)
+ vp = vp->v_parent;
+ }
+ /*
+ * When a mount point is crossed switch the vp.
+ * Continue until we find the root or we find
+ * a vnode that's not the root of a mounted
+ * file system.
+ */
+ tvp = vp;
+
+ while (tvp) {
+ if (tvp == proc_root_dir_vp)
+ goto out_unlock; /* encountered the root */
+
+ if (!(tvp->v_flag & VROOT) || !tvp->v_mount)
+ break; /* not the root of a mounted FS */
+ tvp = tvp->v_mount->mnt_vnodecovered;
+ }
+ if (tvp == NULLVP)
+ goto out_unlock;
+ vp = tvp;
+
+ if (vp && (flags & BUILDPATH_CHECKACCESS)) {
+ vid = vp->v_id;
+
+ NAME_CACHE_UNLOCK();
+
+ if (vp != first_vp && vp != vp_with_iocount) {
+ if (vp_with_iocount) {
+ vnode_put(vp_with_iocount);
+ vp_with_iocount = NULLVP;
+ }
+ if (vnode_getwithvid(vp, vid))
+ goto again;
+ vp_with_iocount = vp;
+ }
+ if ((ret = vnode_authorize(vp, NULL, KAUTH_VNODE_SEARCH, ctx)))
+ goto out; /* no peeking */
+
+ NAME_CACHE_LOCK_SHARED();
+ }
+ }
+out_unlock:
+ NAME_CACHE_UNLOCK();
+out:
+ if (vp_with_iocount)
+ vnode_put(vp_with_iocount);
+ /*
+ * Slide the name down to the beginning of the buffer.
+ */
+ memmove(buff, end, &buff[buflen] - end);
+
+ /*
+ * length includes the trailing zero byte
+ */
+ *outlen = &buff[buflen] - end;
+
+ return (ret);
}
-#else
-#define PURGE(ncp) { \
- LIST_REMOVE(ncp, nc_hash); \
- ncp->nc_hash.le_prev = 0; \
- TAILQ_REMOVE(&nclruhead, ncp, nc_lru); \
- TAILQ_INSERT_HEAD(&nclruhead, ncp, nc_lru); \
- /* this has to come last because it could block */ \
- remove_name(ncp->nc_name); \
- ncp->nc_name = NULL; \
+
+
+/*
+ * return NULLVP if vp's parent doesn't
+ * exist, or we can't get a valid iocount
+ * else return the parent of vp
+ */
+vnode_t
+vnode_getparent(vnode_t vp)
+{
+ vnode_t pvp = NULLVP;
+ int pvid;
+
+ NAME_CACHE_LOCK_SHARED();
+ /*
+ * v_parent is stable behind the name_cache lock
+ * however, the only thing we can really guarantee
+ * is that we've grabbed a valid iocount on the
+ * parent of 'vp' at the time we took the name_cache lock...
+ * once we drop the lock, vp could get re-parented
+ */
+ if ( (pvp = vp->v_parent) != NULLVP ) {
+ pvid = pvp->v_id;
+
+ NAME_CACHE_UNLOCK();
+
+ if (vnode_getwithvid(pvp, pvid) != 0)
+ pvp = NULL;
+ } else
+ NAME_CACHE_UNLOCK();
+ return (pvp);
+}
+
+const char *
+vnode_getname(vnode_t vp)
+{
+ const char *name = NULL;
+
+ NAME_CACHE_LOCK_SHARED();
+
+ if (vp->v_name)
+ name = vfs_addname(vp->v_name, strlen(vp->v_name), 0, 0);
+ NAME_CACHE_UNLOCK();
+
+ return (name);
+}
+
+void
+vnode_putname(const char *name)
+{
+ vfs_removename(name);
+}
+
+
+/*
+ * if VNODE_UPDATE_PARENT, and we can take
+ * a reference on dvp, then update vp with
+ * it's new parent... if vp already has a parent,
+ * then drop the reference vp held on it
+ *
+ * if VNODE_UPDATE_NAME,
+ * then drop string ref on v_name if it exists, and if name is non-NULL
+ * then pick up a string reference on name and record it in v_name...
+ * optionally pass in the length and hashval of name if known
+ *
+ * if VNODE_UPDATE_CACHE, flush the name cache entries associated with vp
+ */
+void
+vnode_update_identity(vnode_t vp, vnode_t dvp, const char *name, int name_len, uint32_t name_hashval, int flags)
+{
+ struct namecache *ncp;
+ vnode_t old_parentvp = NULLVP;
+#if NAMEDSTREAMS
+ int isstream = (vp->v_flag & VISNAMEDSTREAM);
+ int kusecountbumped = 0;
+#endif
+ kauth_cred_t tcred = NULL;
+ const char *vname = NULL;
+ const char *tname = NULL;
+
+ if (flags & VNODE_UPDATE_PARENT) {
+ if (dvp && vnode_ref(dvp) != 0) {
+ dvp = NULLVP;
+ }
+#if NAMEDSTREAMS
+ /* Don't count a stream's parent ref during unmounts */
+ if (isstream && dvp && (dvp != vp) && (dvp != vp->v_parent) && (dvp->v_type == VREG)) {
+ vnode_lock_spin(dvp);
+ ++dvp->v_kusecount;
+ kusecountbumped = 1;
+ vnode_unlock(dvp);
+ }
+#endif
+ } else {
+ dvp = NULLVP;
+ }
+ if ( (flags & VNODE_UPDATE_NAME) ) {
+ if (name != vp->v_name) {
+ if (name && *name) {
+ if (name_len == 0)
+ name_len = strlen(name);
+ tname = vfs_addname(name, name_len, name_hashval, 0);
+ }
+ } else
+ flags &= ~VNODE_UPDATE_NAME;
+ }
+ if ( (flags & (VNODE_UPDATE_PURGE | VNODE_UPDATE_PARENT | VNODE_UPDATE_CACHE | VNODE_UPDATE_NAME)) ) {
+
+ NAME_CACHE_LOCK();
+
+ if ( (flags & VNODE_UPDATE_PURGE) ) {
+
+ if (vp->v_parent)
+ vp->v_parent->v_nc_generation++;
+
+ while ( (ncp = LIST_FIRST(&vp->v_nclinks)) )
+ cache_delete(ncp, 1);
+
+ while ( (ncp = LIST_FIRST(&vp->v_ncchildren)) )
+ cache_delete(ncp, 1);
+
+ /*
+ * Use a temp variable to avoid kauth_cred_unref() while NAME_CACHE_LOCK is held
+ */
+ tcred = vp->v_cred;
+ vp->v_cred = NOCRED;
+ vp->v_authorized_actions = 0;
+ }
+ if ( (flags & VNODE_UPDATE_NAME) ) {
+ vname = vp->v_name;
+ vp->v_name = tname;
+ }
+ if (flags & VNODE_UPDATE_PARENT) {
+ if (dvp != vp && dvp != vp->v_parent) {
+ old_parentvp = vp->v_parent;
+ vp->v_parent = dvp;
+ dvp = NULLVP;
+
+ if (old_parentvp)
+ flags |= VNODE_UPDATE_CACHE;
+ }
+ }
+ if (flags & VNODE_UPDATE_CACHE) {
+ while ( (ncp = LIST_FIRST(&vp->v_nclinks)) )
+ cache_delete(ncp, 1);
+ }
+ NAME_CACHE_UNLOCK();
+
+ if (vname != NULL)
+ vfs_removename(vname);
+
+ if (IS_VALID_CRED(tcred))
+ kauth_cred_unref(&tcred);
+ }
+ if (dvp != NULLVP) {
+#if NAMEDSTREAMS
+ /* Back-out the ref we took if we lost a race for vp->v_parent. */
+ if (kusecountbumped) {
+ vnode_lock_spin(dvp);
+ if (dvp->v_kusecount > 0)
+ --dvp->v_kusecount;
+ vnode_unlock(dvp);
+ }
+#endif
+ vnode_rele(dvp);
+ }
+ if (old_parentvp) {
+ struct uthread *ut;
+
+#if NAMEDSTREAMS
+ if (isstream) {
+ vnode_lock_spin(old_parentvp);
+ if ((old_parentvp->v_type != VDIR) && (old_parentvp->v_kusecount > 0))
+ --old_parentvp->v_kusecount;
+ vnode_unlock(old_parentvp);
+ }
+#endif
+ ut = get_bsdthread_info(current_thread());
+
+ /*
+ * indicated to vnode_rele that it shouldn't do a
+ * vnode_reclaim at this time... instead it will
+ * chain the vnode to the uu_vreclaims list...
+ * we'll be responsible for calling vnode_reclaim
+ * on each of the vnodes in this list...
+ */
+ ut->uu_defer_reclaims = 1;
+ ut->uu_vreclaims = NULLVP;
+
+ while ( (vp = old_parentvp) != NULLVP ) {
+
+ vnode_lock_spin(vp);
+ vnode_rele_internal(vp, 0, 0, 1);
+
+ /*
+ * check to see if the vnode is now in the state
+ * that would have triggered a vnode_reclaim in vnode_rele
+ * if it is, we save it's parent pointer and then NULL
+ * out the v_parent field... we'll drop the reference
+ * that was held on the next iteration of this loop...
+ * this short circuits a potential deep recursion if we
+ * have a long chain of parents in this state...
+ * we'll sit in this loop until we run into
+ * a parent in this chain that is not in this state
+ *
+ * make our check and the vnode_rele atomic
+ * with respect to the current vnode we're working on
+ * by holding the vnode lock
+ * if vnode_rele deferred the vnode_reclaim and has put
+ * this vnode on the list to be reaped by us, than
+ * it has left this vnode with an iocount == 1
+ */
+ if ( (vp->v_iocount == 1) && (vp->v_usecount == 0) &&
+ ((vp->v_lflag & (VL_MARKTERM | VL_TERMINATE | VL_DEAD)) == VL_MARKTERM)) {
+ /*
+ * vnode_rele wanted to do a vnode_reclaim on this vnode
+ * it should be sitting on the head of the uu_vreclaims chain
+ * pull the parent pointer now so that when we do the
+ * vnode_reclaim for each of the vnodes in the uu_vreclaims
+ * list, we won't recurse back through here
+ *
+ * need to do a convert here in case vnode_rele_internal
+ * returns with the lock held in the spin mode... it
+ * can drop and retake the lock under certain circumstances
+ */
+ vnode_lock_convert(vp);
+
+ NAME_CACHE_LOCK();
+ old_parentvp = vp->v_parent;
+ vp->v_parent = NULLVP;
+ NAME_CACHE_UNLOCK();
+ } else {
+ /*
+ * we're done... we ran into a vnode that isn't
+ * being terminated
+ */
+ old_parentvp = NULLVP;
+ }
+ vnode_unlock(vp);
+ }
+ ut->uu_defer_reclaims = 0;
+
+ while ( (vp = ut->uu_vreclaims) != NULLVP) {
+ ut->uu_vreclaims = vp->v_defer_reclaimlist;
+
+ /*
+ * vnode_put will drive the vnode_reclaim if
+ * we are still the only reference on this vnode
+ */
+ vnode_put(vp);
+ }
+ }
+}
+
+
+/*
+ * Mark a vnode as having multiple hard links. HFS makes use of this
+ * because it keeps track of each link separately, and wants to know
+ * which link was actually used.
+ *
+ * This will cause the name cache to force a VNOP_LOOKUP on the vnode
+ * so that HFS can post-process the lookup. Also, volfs will call
+ * VNOP_GETATTR2 to determine the parent, instead of using v_parent.
+ */
+void vnode_setmultipath(vnode_t vp)
+{
+ vnode_lock_spin(vp);
+
+ /*
+ * In theory, we're changing the vnode's identity as far as the
+ * name cache is concerned, so we ought to grab the name cache lock
+ * here. However, there is already a race, and grabbing the name
+ * cache lock only makes the race window slightly smaller.
+ *
+ * The race happens because the vnode already exists in the name
+ * cache, and could be found by one thread before another thread
+ * can set the hard link flag.
+ */
+
+ vp->v_flag |= VISHARDLINK;
+
+ vnode_unlock(vp);
+}
+
+
+
+/*
+ * backwards compatibility
+ */
+void vnode_uncache_credentials(vnode_t vp)
+{
+ vnode_uncache_authorized_action(vp, KAUTH_INVALIDATE_CACHED_RIGHTS);
+}
+
+
+/*
+ * use the exclusive form of NAME_CACHE_LOCK to protect the update of the
+ * following fields in the vnode: v_cred_timestamp, v_cred, v_authorized_actions
+ * we use this lock so that we can look at the v_cred and v_authorized_actions
+ * atomically while behind the NAME_CACHE_LOCK in shared mode in 'cache_lookup_path',
+ * which is the super-hot path... if we are updating the authorized actions for this
+ * vnode, we are already in the super-slow and far less frequented path so its not
+ * that bad that we take the lock exclusive for this case... of course we strive
+ * to hold it for the minimum amount of time possible
+ */
+
+void vnode_uncache_authorized_action(vnode_t vp, kauth_action_t action)
+{
+ kauth_cred_t tcred = NOCRED;
+
+ NAME_CACHE_LOCK();
+
+ vp->v_authorized_actions &= ~action;
+
+ if (action == KAUTH_INVALIDATE_CACHED_RIGHTS &&
+ IS_VALID_CRED(vp->v_cred)) {
+ /*
+ * Use a temp variable to avoid kauth_cred_unref() while NAME_CACHE_LOCK is held
+ */
+ tcred = vp->v_cred;
+ vp->v_cred = NOCRED;
+ }
+ NAME_CACHE_UNLOCK();
+
+ if (tcred != NOCRED)
+ kauth_cred_unref(&tcred);
+}
+
+
+extern int bootarg_vnode_cache_defeat; /* default = 0, from bsd_init.c */
+
+boolean_t
+vnode_cache_is_authorized(vnode_t vp, vfs_context_t ctx, kauth_action_t action)
+{
+ kauth_cred_t ucred;
+ boolean_t retval = FALSE;
+
+ /* Boot argument to defeat rights caching */
+ if (bootarg_vnode_cache_defeat)
+ return FALSE;
+
+ if ( (vp->v_mount->mnt_kern_flag & (MNTK_AUTH_OPAQUE | MNTK_AUTH_CACHE_TTL)) ) {
+ /*
+ * a TTL is enabled on the rights cache... handle it here
+ * a TTL of 0 indicates that no rights should be cached
+ */
+ if (vp->v_mount->mnt_authcache_ttl) {
+ if ( !(vp->v_mount->mnt_kern_flag & MNTK_AUTH_CACHE_TTL) ) {
+ /*
+ * For filesystems marked only MNTK_AUTH_OPAQUE (generally network ones),
+ * we will only allow a SEARCH right on a directory to be cached...
+ * that cached right always has a default TTL associated with it
+ */
+ if (action != KAUTH_VNODE_SEARCH || vp->v_type != VDIR)
+ vp = NULLVP;
+ }
+ if (vp != NULLVP && vnode_cache_is_stale(vp) == TRUE) {
+ vnode_uncache_authorized_action(vp, vp->v_authorized_actions);
+ vp = NULLVP;
+ }
+ } else
+ vp = NULLVP;
+ }
+ if (vp != NULLVP) {
+ ucred = vfs_context_ucred(ctx);
+
+ NAME_CACHE_LOCK_SHARED();
+
+ if (vp->v_cred == ucred && (vp->v_authorized_actions & action) == action)
+ retval = TRUE;
+
+ NAME_CACHE_UNLOCK();
+ }
+ return retval;
+}
+
+
+void vnode_cache_authorized_action(vnode_t vp, vfs_context_t ctx, kauth_action_t action)
+{
+ kauth_cred_t tcred = NOCRED;
+ kauth_cred_t ucred;
+ struct timeval tv;
+ boolean_t ttl_active = FALSE;
+
+ ucred = vfs_context_ucred(ctx);
+
+ if (!IS_VALID_CRED(ucred) || action == 0)
+ return;
+
+ if ( (vp->v_mount->mnt_kern_flag & (MNTK_AUTH_OPAQUE | MNTK_AUTH_CACHE_TTL)) ) {
+ /*
+ * a TTL is enabled on the rights cache... handle it here
+ * a TTL of 0 indicates that no rights should be cached
+ */
+ if (vp->v_mount->mnt_authcache_ttl == 0)
+ return;
+
+ if ( !(vp->v_mount->mnt_kern_flag & MNTK_AUTH_CACHE_TTL) ) {
+ /*
+ * only cache SEARCH action for filesystems marked
+ * MNTK_AUTH_OPAQUE on VDIRs...
+ * the lookup_path code will time these out
+ */
+ if ( (action & ~KAUTH_VNODE_SEARCH) || vp->v_type != VDIR )
+ return;
+ }
+ ttl_active = TRUE;
+
+ microuptime(&tv);
+ }
+ NAME_CACHE_LOCK();
+
+ if (vp->v_cred != ucred) {
+ kauth_cred_ref(ucred);
+ /*
+ * Use a temp variable to avoid kauth_cred_unref() while NAME_CACHE_LOCK is held
+ */
+ tcred = vp->v_cred;
+ vp->v_cred = ucred;
+ vp->v_authorized_actions = 0;
+ }
+ if (ttl_active == TRUE && vp->v_authorized_actions == 0) {
+ /*
+ * only reset the timestamnp on the
+ * first authorization cached after the previous
+ * timer has expired or we're switching creds...
+ * 'vnode_cache_is_authorized' will clear the
+ * authorized actions if the TTL is active and
+ * it has expired
+ */
+ vp->v_cred_timestamp = tv.tv_sec;
+ }
+ vp->v_authorized_actions |= action;
+
+ NAME_CACHE_UNLOCK();
+
+ if (IS_VALID_CRED(tcred))
+ kauth_cred_unref(&tcred);
+}
+
+
+boolean_t vnode_cache_is_stale(vnode_t vp)
+{
+ struct timeval tv;
+ boolean_t retval;
+
+ microuptime(&tv);
+
+ if ((tv.tv_sec - vp->v_cred_timestamp) > vp->v_mount->mnt_authcache_ttl)
+ retval = TRUE;
+ else
+ retval = FALSE;
+
+ return retval;
}
-#endif /* DIAGNOSTIC */
+
+
/*
- * Move an entry that has been used to the tail of the LRU list
- * so that it will be preserved for future use.
+ * Returns: 0 Success
+ * ERECYCLE vnode was recycled from underneath us. Force lookup to be re-driven from namei.
+ * This errno value should not be seen by anyone outside of the kernel.
*/
-#define TOUCH(ncp) { \
- if (ncp->nc_lru.tqe_next != 0) { \
- TAILQ_REMOVE(&nclruhead, ncp, nc_lru); \
- TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru); \
- } \
+int
+cache_lookup_path(struct nameidata *ndp, struct componentname *cnp, vnode_t dp,
+ vfs_context_t ctx, int *dp_authorized, vnode_t last_dp)
+{
+ char *cp; /* pointer into pathname argument */
+ int vid;
+ int vvid = 0; /* protected by vp != NULLVP */
+ vnode_t vp = NULLVP;
+ vnode_t tdp = NULLVP;
+ kauth_cred_t ucred;
+ boolean_t ttl_enabled = FALSE;
+ struct timeval tv;
+ mount_t mp;
+ unsigned int hash;
+ int error = 0;
+
+#if CONFIG_TRIGGERS
+ vnode_t trigger_vp;
+#endif /* CONFIG_TRIGGERS */
+
+ ucred = vfs_context_ucred(ctx);
+ ndp->ni_flag &= ~(NAMEI_TRAILINGSLASH);
+
+ NAME_CACHE_LOCK_SHARED();
+
+ if ( dp->v_mount && (dp->v_mount->mnt_kern_flag & (MNTK_AUTH_OPAQUE | MNTK_AUTH_CACHE_TTL)) ) {
+ ttl_enabled = TRUE;
+ microuptime(&tv);
+ }
+ for (;;) {
+ /*
+ * Search a directory.
+ *
+ * The cn_hash value is for use by cache_lookup
+ * The last component of the filename is left accessible via
+ * cnp->cn_nameptr for callers that need the name.
+ */
+ hash = 0;
+ cp = cnp->cn_nameptr;
+
+ while (*cp && (*cp != '/')) {
+ hash = crc32tab[((hash >> 24) ^ (unsigned char)*cp++)] ^ hash << 8;
+ }
+ /*
+ * the crc generator can legitimately generate
+ * a 0... however, 0 for us means that we
+ * haven't computed a hash, so use 1 instead
+ */
+ if (hash == 0)
+ hash = 1;
+ cnp->cn_hash = hash;
+ cnp->cn_namelen = cp - cnp->cn_nameptr;
+
+ ndp->ni_pathlen -= cnp->cn_namelen;
+ ndp->ni_next = cp;
+
+ /*
+ * Replace multiple slashes by a single slash and trailing slashes
+ * by a null. This must be done before VNOP_LOOKUP() because some
+ * fs's don't know about trailing slashes. Remember if there were
+ * trailing slashes to handle symlinks, existing non-directories
+ * and non-existing files that won't be directories specially later.
+ */
+ while (*cp == '/' && (cp[1] == '/' || cp[1] == '\0')) {
+ cp++;
+ ndp->ni_pathlen--;
+
+ if (*cp == '\0') {
+ ndp->ni_flag |= NAMEI_TRAILINGSLASH;
+ *ndp->ni_next = '\0';
+ }
+ }
+ ndp->ni_next = cp;
+
+ cnp->cn_flags &= ~(MAKEENTRY | ISLASTCN | ISDOTDOT);
+
+ if (*cp == '\0')
+ cnp->cn_flags |= ISLASTCN;
+
+ if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.' && cnp->cn_nameptr[0] == '.')
+ cnp->cn_flags |= ISDOTDOT;
+
+ *dp_authorized = 0;
+#if NAMEDRSRCFORK
+ /*
+ * Process a request for a file's resource fork.
+ *
+ * Consume the _PATH_RSRCFORKSPEC suffix and tag the path.
+ */
+ if ((ndp->ni_pathlen == sizeof(_PATH_RSRCFORKSPEC)) &&
+ (cp[1] == '.' && cp[2] == '.') &&
+ bcmp(cp, _PATH_RSRCFORKSPEC, sizeof(_PATH_RSRCFORKSPEC)) == 0) {
+ /* Skip volfs file systems that don't support native streams. */
+ if ((dp->v_mount != NULL) &&
+ (dp->v_mount->mnt_flag & MNT_DOVOLFS) &&
+ (dp->v_mount->mnt_kern_flag & MNTK_NAMED_STREAMS) == 0) {
+ goto skiprsrcfork;
+ }
+ cnp->cn_flags |= CN_WANTSRSRCFORK;
+ cnp->cn_flags |= ISLASTCN;
+ ndp->ni_next[0] = '\0';
+ ndp->ni_pathlen = 1;
+ }
+skiprsrcfork:
+#endif
+
+#if CONFIG_MACF
+
+ /*
+ * Name cache provides authorization caching (see below)
+ * that will short circuit MAC checks in lookup().
+ * We must perform MAC check here. On denial
+ * dp_authorized will remain 0 and second check will
+ * be perfomed in lookup().
+ */
+ if (!(cnp->cn_flags & DONOTAUTH)) {
+ error = mac_vnode_check_lookup(ctx, dp, cnp);
+ if (error) {
+ NAME_CACHE_UNLOCK();
+ goto errorout;
+ }
+ }
+#endif /* MAC */
+ if (ttl_enabled && ((tv.tv_sec - dp->v_cred_timestamp) > dp->v_mount->mnt_authcache_ttl))
+ break;
+
+ /*
+ * NAME_CACHE_LOCK holds these fields stable
+ */
+ if ((dp->v_cred != ucred || !(dp->v_authorized_actions & KAUTH_VNODE_SEARCH)) &&
+ !(dp->v_authorized_actions & KAUTH_VNODE_SEARCHBYANYONE))
+ break;
+
+ /*
+ * indicate that we're allowed to traverse this directory...
+ * even if we fail the cache lookup or decide to bail for
+ * some other reason, this information is valid and is used
+ * to avoid doing a vnode_authorize before the call to VNOP_LOOKUP
+ */
+ *dp_authorized = 1;
+
+ if ( (cnp->cn_flags & (ISLASTCN | ISDOTDOT)) ) {
+ if (cnp->cn_nameiop != LOOKUP)
+ break;
+ if (cnp->cn_flags & LOCKPARENT)
+ break;
+ if (cnp->cn_flags & NOCACHE)
+ break;
+ if (cnp->cn_flags & ISDOTDOT) {
+ /*
+ * Force directory hardlinks to go to
+ * file system for ".." requests.
+ */
+ if (dp && (dp->v_flag & VISHARDLINK)) {
+ break;
+ }
+ /*
+ * Quit here only if we can't use
+ * the parent directory pointer or
+ * don't have one. Otherwise, we'll
+ * use it below.
+ */
+ if ((dp->v_flag & VROOT) ||
+ dp == ndp->ni_rootdir ||
+ dp->v_parent == NULLVP)
+ break;
+ }
+ }
+
+ /*
+ * "." and ".." aren't supposed to be cached, so check
+ * for them before checking the cache.
+ */
+ if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.')
+ vp = dp;
+ else if ( (cnp->cn_flags & ISDOTDOT) )
+ vp = dp->v_parent;
+ else {
+ if ( (vp = cache_lookup_locked(dp, cnp)) == NULLVP)
+ break;
+
+ if ( (vp->v_flag & VISHARDLINK) ) {
+ /*
+ * The file system wants a VNOP_LOOKUP on this vnode
+ */
+ vp = NULL;
+ break;
+ }
+ }
+ if ( (cnp->cn_flags & ISLASTCN) )
+ break;
+
+ if (vp->v_type != VDIR) {
+ if (vp->v_type != VLNK)
+ vp = NULL;
+ break;
+ }
+
+ if ( (mp = vp->v_mountedhere) && ((cnp->cn_flags & NOCROSSMOUNT) == 0)) {
+
+ if (mp->mnt_realrootvp == NULLVP || mp->mnt_generation != mount_generation ||
+ mp->mnt_realrootvp_vid != mp->mnt_realrootvp->v_id)
+ break;
+ vp = mp->mnt_realrootvp;
+ }
+
+#if CONFIG_TRIGGERS
+ /*
+ * After traversing all mountpoints stacked here, if we have a
+ * trigger in hand, resolve it. Note that we don't need to
+ * leave the fast path if the mount has already happened.
+ */
+ if ((vp->v_resolve != NULL) &&
+ (vp->v_resolve->vr_resolve_func != NULL)) {
+ break;
+ }
+#endif /* CONFIG_TRIGGERS */
+
+
+ dp = vp;
+ vp = NULLVP;
+
+ cnp->cn_nameptr = ndp->ni_next + 1;
+ ndp->ni_pathlen--;
+ while (*cnp->cn_nameptr == '/') {
+ cnp->cn_nameptr++;
+ ndp->ni_pathlen--;
+ }
+ }
+ if (vp != NULLVP)
+ vvid = vp->v_id;
+ vid = dp->v_id;
+
+ NAME_CACHE_UNLOCK();
+
+ if ((vp != NULLVP) && (vp->v_type != VLNK) &&
+ ((cnp->cn_flags & (ISLASTCN | LOCKPARENT | WANTPARENT | SAVESTART)) == ISLASTCN)) {
+ /*
+ * if we've got a child and it's the last component, and
+ * the lookup doesn't need to return the parent then we
+ * can skip grabbing an iocount on the parent, since all
+ * we're going to do with it is a vnode_put just before
+ * we return from 'lookup'. If it's a symbolic link,
+ * we need the parent in case the link happens to be
+ * a relative pathname.
+ */
+ tdp = dp;
+ dp = NULLVP;
+ } else {
+need_dp:
+ /*
+ * return the last directory we looked at
+ * with an io reference held. If it was the one passed
+ * in as a result of the last iteration of VNOP_LOOKUP,
+ * it should already hold an io ref. No need to increase ref.
+ */
+ if (last_dp != dp){
+
+ if (dp == ndp->ni_usedvp) {
+ /*
+ * if this vnode matches the one passed in via USEDVP
+ * than this context already holds an io_count... just
+ * use vnode_get to get an extra ref for lookup to play
+ * with... can't use the getwithvid variant here because
+ * it will block behind a vnode_drain which would result
+ * in a deadlock (since we already own an io_count that the
+ * vnode_drain is waiting on)... vnode_get grabs the io_count
+ * immediately w/o waiting... it always succeeds
+ */
+ vnode_get(dp);
+ } else if ( (vnode_getwithvid_drainok(dp, vid)) ) {
+ /*
+ * failure indicates the vnode
+ * changed identity or is being
+ * TERMINATED... in either case
+ * punt this lookup.
+ *
+ * don't necessarily return ENOENT, though, because
+ * we really want to go back to disk and make sure it's
+ * there or not if someone else is changing this
+ * vnode.
+ */
+ error = ERECYCLE;
+ goto errorout;
+ }
+ }
+ }
+ if (vp != NULLVP) {
+ if ( (vnode_getwithvid_drainok(vp, vvid)) ) {
+ vp = NULLVP;
+
+ /*
+ * can't get reference on the vp we'd like
+ * to return... if we didn't grab a reference
+ * on the directory (due to fast path bypass),
+ * then we need to do it now... we can't return
+ * with both ni_dvp and ni_vp NULL, and no
+ * error condition
+ */
+ if (dp == NULLVP) {
+ dp = tdp;
+ goto need_dp;
+ }
+ }
+ }
+
+ ndp->ni_dvp = dp;
+ ndp->ni_vp = vp;
+
+#if CONFIG_TRIGGERS
+ trigger_vp = vp ? vp : dp;
+ if ((error == 0) && (trigger_vp != NULLVP) && vnode_isdir(trigger_vp)) {
+ error = vnode_trigger_resolve(trigger_vp, ndp, ctx);
+ if (error) {
+ if (vp)
+ vnode_put(vp);
+ if (dp)
+ vnode_put(dp);
+ goto errorout;
+ }
+ }
+#endif /* CONFIG_TRIGGERS */
+
+errorout:
+ /*
+ * If we came into cache_lookup_path after an iteration of the lookup loop that
+ * resulted in a call to VNOP_LOOKUP, then VNOP_LOOKUP returned a vnode with a io ref
+ * on it. It is now the job of cache_lookup_path to drop the ref on this vnode
+ * when it is no longer needed. If we get to this point, and last_dp is not NULL
+ * and it is ALSO not the dvp we want to return to caller of this function, it MUST be
+ * the case that we got to a subsequent path component and this previous vnode is
+ * no longer needed. We can then drop the io ref on it.
+ */
+ if ((last_dp != NULLVP) && (last_dp != ndp->ni_dvp)){
+ vnode_put(last_dp);
+ }
+
+ //initialized to 0, should be the same if no error cases occurred.
+ return error;
+}
+
+
+static vnode_t
+cache_lookup_locked(vnode_t dvp, struct componentname *cnp)
+{
+ struct namecache *ncp;
+ struct nchashhead *ncpp;
+ long namelen = cnp->cn_namelen;
+ unsigned int hashval = (cnp->cn_hash & NCHASHMASK);
+
+ if (nc_disabled) {
+ return NULL;
+ }
+
+ ncpp = NCHHASH(dvp, cnp->cn_hash);
+ LIST_FOREACH(ncp, ncpp, nc_hash) {
+ if ((ncp->nc_dvp == dvp) && (ncp->nc_hashval == hashval)) {
+ if (memcmp(ncp->nc_name, cnp->cn_nameptr, namelen) == 0 && ncp->nc_name[namelen] == 0)
+ break;
+ }
+ }
+ if (ncp == 0) {
+ /*
+ * We failed to find an entry
+ */
+ NCHSTAT(ncs_miss);
+ return (NULL);
+ }
+ NCHSTAT(ncs_goodhits);
+
+ return (ncp->nc_vp);
}
// hash part of a componentname.
//
static unsigned int
-hash_string(const char *str, int len)
+hash_string(const char *cp, int len)
{
- unsigned int i, hashval = 0;
+ unsigned hash = 0;
- if (len == 0) {
- for(i=1; *str != 0; i++, str++) {
- hashval += (unsigned char)*str * i;
- }
+ if (len) {
+ while (len--) {
+ hash = crc32tab[((hash >> 24) ^ (unsigned char)*cp++)] ^ hash << 8;
+ }
} else {
- for(i=len; i > 0; i--, str++) {
- hashval += (unsigned char)*str * (len - i + 1);
- }
+ while (*cp != '\0') {
+ hash = crc32tab[((hash >> 24) ^ (unsigned char)*cp++)] ^ hash << 8;
+ }
}
-
- return hashval;
+ /*
+ * the crc generator can legitimately generate
+ * a 0... however, 0 for us means that we
+ * haven't computed a hash, so use 1 instead
+ */
+ if (hash == 0)
+ hash = 1;
+ return hash;
}
-
-
/*
* Lookup an entry in the cache
*
*/
int
-cache_lookup(dvp, vpp, cnp)
- struct vnode *dvp;
- struct vnode **vpp;
- struct componentname *cnp;
-{
- register struct namecache *ncp, *nnp;
- register struct nchashhead *ncpp;
- register long namelen = cnp->cn_namelen;
- char *nameptr = cnp->cn_nameptr;
-
- if (!doingcache) {
- cnp->cn_flags &= ~MAKEENTRY;
- return (0);
+cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
+{
+ struct namecache *ncp;
+ struct nchashhead *ncpp;
+ long namelen = cnp->cn_namelen;
+ unsigned int hashval;
+ boolean_t have_exclusive = FALSE;
+ uint32_t vid;
+ vnode_t vp;
+
+ if (cnp->cn_hash == 0)
+ cnp->cn_hash = hash_string(cnp->cn_nameptr, cnp->cn_namelen);
+ hashval = (cnp->cn_hash & NCHASHMASK);
+
+ if (nc_disabled) {
+ return 0;
}
+ NAME_CACHE_LOCK_SHARED();
+
+relook:
ncpp = NCHHASH(dvp, cnp->cn_hash);
- for (ncp = ncpp->lh_first; ncp != 0; ncp = nnp) {
- nnp = ncp->nc_hash.le_next;
-
- if (ncp->nc_dvp == dvp &&
- strncmp(ncp->nc_name, nameptr, namelen) == 0 &&
- ncp->nc_name[namelen] == 0) {
- /* Make sure the vp isn't stale. */
- if ((ncp->nc_dvpid != dvp->v_id) ||
- (ncp->nc_vp && ncp->nc_vpid != ncp->nc_vp->v_id)) {
- nchstats.ncs_falsehits++;
- PURGE(ncp);
- continue;
- }
- break;
+ LIST_FOREACH(ncp, ncpp, nc_hash) {
+ if ((ncp->nc_dvp == dvp) && (ncp->nc_hashval == hashval)) {
+ if (memcmp(ncp->nc_name, cnp->cn_nameptr, namelen) == 0 && ncp->nc_name[namelen] == 0)
+ break;
}
}
-
/* We failed to find an entry */
if (ncp == 0) {
- nchstats.ncs_miss++;
+ NCHSTAT(ncs_miss);
+ NAME_CACHE_UNLOCK();
return (0);
}
/* We don't want to have an entry, so dump it */
if ((cnp->cn_flags & MAKEENTRY) == 0) {
- nchstats.ncs_badhits++;
- PURGE(ncp);
- return (0);
+ if (have_exclusive == TRUE) {
+ NCHSTAT(ncs_badhits);
+ cache_delete(ncp, 1);
+ NAME_CACHE_UNLOCK();
+ return (0);
+ }
+ NAME_CACHE_UNLOCK();
+ NAME_CACHE_LOCK();
+ have_exclusive = TRUE;
+ goto relook;
}
+ vp = ncp->nc_vp;
/* We found a "positive" match, return the vnode */
- if (ncp->nc_vp) {
- if (ncp->nc_vp->v_flag & (VUINIT|VXLOCK|VTERMINATE|VORECLAIM)) {
- PURGE(ncp);
- return (0);
- }
+ if (vp) {
+ NCHSTAT(ncs_goodhits);
+
+ vid = vp->v_id;
+ NAME_CACHE_UNLOCK();
- nchstats.ncs_goodhits++;
- TOUCH(ncp);
- *vpp = ncp->nc_vp;
+ if (vnode_getwithvid(vp, vid)) {
+#if COLLECT_STATS
+ NAME_CACHE_LOCK();
+ NCHSTAT(ncs_badvid);
+ NAME_CACHE_UNLOCK();
+#endif
+ return (0);
+ }
+ *vpp = vp;
return (-1);
}
/* We found a negative match, and want to create it, so purge */
- if (cnp->cn_nameiop == CREATE) {
- nchstats.ncs_badhits++;
- PURGE(ncp);
- return (0);
+ if (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME) {
+ if (have_exclusive == TRUE) {
+ NCHSTAT(ncs_badhits);
+ cache_delete(ncp, 1);
+ NAME_CACHE_UNLOCK();
+ return (0);
+ }
+ NAME_CACHE_UNLOCK();
+ NAME_CACHE_LOCK();
+ have_exclusive = TRUE;
+ goto relook;
}
/*
* We found a "negative" match, ENOENT notifies client of this match.
- * The nc_vpid field records whether this is a whiteout.
+ * The nc_whiteout field records whether this is a whiteout.
*/
- nchstats.ncs_neghits++;
- TOUCH(ncp);
- cnp->cn_flags |= ncp->nc_vpid;
+ NCHSTAT(ncs_neghits);
+
+ if (ncp->nc_whiteout)
+ cnp->cn_flags |= ISWHITEOUT;
+ NAME_CACHE_UNLOCK();
return (ENOENT);
}
+const char *
+cache_enter_create(vnode_t dvp, vnode_t vp, struct componentname *cnp)
+{
+ const char *strname;
+
+ if (cnp->cn_hash == 0)
+ cnp->cn_hash = hash_string(cnp->cn_nameptr, cnp->cn_namelen);
+
+ /*
+ * grab 2 references on the string entered
+ * one for the cache_enter_locked to consume
+ * and the second to be consumed by v_name (vnode_create call point)
+ */
+ strname = add_name_internal(cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, TRUE, 0);
+
+ NAME_CACHE_LOCK();
+
+ cache_enter_locked(dvp, vp, cnp, strname);
+
+ NAME_CACHE_UNLOCK();
+
+ return (strname);
+}
+
+
+/*
+ * Add an entry to the cache...
+ * but first check to see if the directory
+ * that this entry is to be associated with has
+ * had any cache_purges applied since we took
+ * our identity snapshot... this check needs to
+ * be done behind the name cache lock
+ */
+void
+cache_enter_with_gen(struct vnode *dvp, struct vnode *vp, struct componentname *cnp, int gen)
+{
+
+ if (cnp->cn_hash == 0)
+ cnp->cn_hash = hash_string(cnp->cn_nameptr, cnp->cn_namelen);
+
+ NAME_CACHE_LOCK();
+
+ if (dvp->v_nc_generation == gen)
+ (void)cache_enter_locked(dvp, vp, cnp, NULL);
+
+ NAME_CACHE_UNLOCK();
+}
+
+
/*
* Add an entry to the cache.
*/
void
-cache_enter(dvp, vp, cnp)
- struct vnode *dvp;
- struct vnode *vp;
- struct componentname *cnp;
+cache_enter(struct vnode *dvp, struct vnode *vp, struct componentname *cnp)
+{
+ const char *strname;
+
+ if (cnp->cn_hash == 0)
+ cnp->cn_hash = hash_string(cnp->cn_nameptr, cnp->cn_namelen);
+
+ /*
+ * grab 1 reference on the string entered
+ * for the cache_enter_locked to consume
+ */
+ strname = add_name_internal(cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, FALSE, 0);
+
+ NAME_CACHE_LOCK();
+
+ cache_enter_locked(dvp, vp, cnp, strname);
+
+ NAME_CACHE_UNLOCK();
+}
+
+
+static void
+cache_enter_locked(struct vnode *dvp, struct vnode *vp, struct componentname *cnp, const char *strname)
{
- register struct namecache *ncp;
- register struct nchashhead *ncpp;
+ struct namecache *ncp, *negp;
+ struct nchashhead *ncpp;
- if (!doingcache)
+ if (nc_disabled)
return;
+ /*
+ * if the entry is for -ve caching vp is null
+ */
+ if ((vp != NULLVP) && (LIST_FIRST(&vp->v_nclinks))) {
+ /*
+ * someone beat us to the punch..
+ * this vnode is already in the cache
+ */
+ if (strname != NULL)
+ vfs_removename(strname);
+ return;
+ }
/*
* We allocate a new entry if we are less than the maximum
- * allowed and the one at the front of the LRU list is in use.
- * Otherwise we use the one at the front of the LRU list.
+ * allowed and the one at the front of the list is in use.
+ * Otherwise we use the one at the front of the list.
*/
- if (numcache < desiredvnodes &&
- ((ncp = nclruhead.tqh_first) == NULL ||
- ncp->nc_hash.le_prev != 0)) {
- /* Add one more entry */
- ncp = (struct namecache *)
- _MALLOC_ZONE((u_long)sizeof *ncp, M_CACHE, M_WAITOK);
+ if (numcache < desiredNodes &&
+ ((ncp = nchead.tqh_first) == NULL ||
+ ncp->nc_hash.le_prev != 0)) {
+ /*
+ * Allocate one more entry
+ */
+ ncp = (struct namecache *)_MALLOC_ZONE(sizeof(*ncp), M_CACHE, M_WAITOK);
numcache++;
- } else if (ncp = nclruhead.tqh_first) {
- /* reuse an old entry */
- TAILQ_REMOVE(&nclruhead, ncp, nc_lru);
+ } else {
+ /*
+ * reuse an old entry
+ */
+ ncp = TAILQ_FIRST(&nchead);
+ TAILQ_REMOVE(&nchead, ncp, nc_entry);
+
if (ncp->nc_hash.le_prev != 0) {
-#if DIAGNOSTIC
- if (ncp->nc_hash.le_next == ncp)
- panic("cache_enter: le_next");
-#endif
- LIST_REMOVE(ncp, nc_hash);
- remove_name(ncp->nc_name);
- ncp->nc_name = NULL;
- ncp->nc_hash.le_prev = 0;
+ /*
+ * still in use... we need to
+ * delete it before re-using it
+ */
+ NCHSTAT(ncs_stolen);
+ cache_delete(ncp, 0);
}
- } else {
- /* give up */
- return;
}
+ NCHSTAT(ncs_enters);
/*
* Fill in cache info, if vp is NULL this is a "negative" cache entry.
- * For negative entries, we have to record whether it is a whiteout.
- * the whiteout flag is stored in the nc_vpid field which is
- * otherwise unused.
*/
ncp->nc_vp = vp;
- if (vp)
- ncp->nc_vpid = vp->v_id;
- else
- ncp->nc_vpid = cnp->cn_flags & ISWHITEOUT;
ncp->nc_dvp = dvp;
- ncp->nc_dvpid = dvp->v_id;
- ncp->nc_name = add_name(cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, 0);
- TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru);
+ ncp->nc_hashval = cnp->cn_hash;
+ ncp->nc_whiteout = FALSE;
+
+ if (strname == NULL)
+ ncp->nc_name = add_name_internal(cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, FALSE, 0);
+ else
+ ncp->nc_name = strname;
+ /*
+ * make us the newest entry in the cache
+ * i.e. we'll be the last to be stolen
+ */
+ TAILQ_INSERT_TAIL(&nchead, ncp, nc_entry);
+
ncpp = NCHHASH(dvp, cnp->cn_hash);
#if DIAGNOSTIC
{
- register struct namecache *p;
+ struct namecache *p;
for (p = ncpp->lh_first; p != 0; p = p->nc_hash.le_next)
if (p == ncp)
panic("cache_enter: duplicate");
}
#endif
+ /*
+ * make us available to be found via lookup
+ */
LIST_INSERT_HEAD(ncpp, ncp, nc_hash);
+
+ if (vp) {
+ /*
+ * add to the list of name cache entries
+ * that point at vp
+ */
+ LIST_INSERT_HEAD(&vp->v_nclinks, ncp, nc_un.nc_link);
+ } else {
+ /*
+ * this is a negative cache entry (vp == NULL)
+ * stick it on the negative cache list
+ * and record the whiteout state
+ */
+ TAILQ_INSERT_TAIL(&neghead, ncp, nc_un.nc_negentry);
+
+ if (cnp->cn_flags & ISWHITEOUT)
+ ncp->nc_whiteout = TRUE;
+ ncs_negtotal++;
+
+ if (ncs_negtotal > desiredNegNodes) {
+ /*
+ * if we've reached our desired limit
+ * of negative cache entries, delete
+ * the oldest
+ */
+ negp = TAILQ_FIRST(&neghead);
+ cache_delete(negp, 1);
+ }
+ }
+ /*
+ * add us to the list of name cache entries that
+ * are children of dvp
+ */
+ LIST_INSERT_HEAD(&dvp->v_ncchildren, ncp, nc_child);
}
+
+/*
+ * Initialize CRC-32 remainder table.
+ */
+static void init_crc32(void)
+{
+ /*
+ * the CRC-32 generator polynomial is:
+ * x^32 + x^26 + x^23 + x^22 + x^16 + x^12 + x^10
+ * + x^8 + x^7 + x^5 + x^4 + x^2 + x + 1
+ */
+ unsigned int crc32_polynomial = 0x04c11db7;
+ unsigned int i,j;
+
+ /*
+ * pre-calculate the CRC-32 remainder for each possible octet encoding
+ */
+ for (i = 0; i < 256; i++) {
+ unsigned int crc_rem = i << 24;
+
+ for (j = 0; j < 8; j++) {
+ if (crc_rem & 0x80000000)
+ crc_rem = (crc_rem << 1) ^ crc32_polynomial;
+ else
+ crc_rem = (crc_rem << 1);
+ }
+ crc32tab[i] = crc_rem;
+ }
+}
+
+
/*
* Name cache initialization, from vfs_init() when we are booting
*/
void
-nchinit()
+nchinit(void)
{
- static void init_string_table(void);
+ int i;
+
+ desiredNegNodes = (desiredvnodes / 10);
+ desiredNodes = desiredvnodes + desiredNegNodes;
- TAILQ_INIT(&nclruhead);
- nchashtbl = hashinit(MAX(4096, desiredvnodes), M_CACHE, &nchash);
+ TAILQ_INIT(&nchead);
+ TAILQ_INIT(&neghead);
- init_string_table();
+ init_crc32();
+
+ nchashtbl = hashinit(MAX(CONFIG_NC_HASH, (2 *desiredNodes)), M_CACHE, &nchash);
+ nchashmask = nchash;
+ nchash++;
+
+ init_string_table();
+
+ /* Allocate name cache lock group attribute and group */
+ namecache_lck_grp_attr= lck_grp_attr_alloc_init();
+
+ namecache_lck_grp = lck_grp_alloc_init("Name Cache", namecache_lck_grp_attr);
+
+ /* Allocate name cache lock attribute */
+ namecache_lck_attr = lck_attr_alloc_init();
+
+ /* Allocate name cache lock */
+ namecache_rw_lock = lck_rw_alloc_init(namecache_lck_grp, namecache_lck_attr);
+
+
+ /* Allocate string cache lock group attribute and group */
+ strcache_lck_grp_attr= lck_grp_attr_alloc_init();
+
+ strcache_lck_grp = lck_grp_alloc_init("String Cache", strcache_lck_grp_attr);
+
+ /* Allocate string cache lock attribute */
+ strcache_lck_attr = lck_attr_alloc_init();
+
+ /* Allocate string cache lock */
+ strtable_rw_lock = lck_rw_alloc_init(strcache_lck_grp, strcache_lck_attr);
+
+ for (i = 0; i < NUM_STRCACHE_LOCKS; i++)
+ lck_mtx_init(&strcache_mtx_locks[i], strcache_lck_grp, strcache_lck_attr);
+}
+
+void
+name_cache_lock_shared(void)
+{
+ lck_rw_lock_shared(namecache_rw_lock);
+}
+
+void
+name_cache_lock(void)
+{
+ lck_rw_lock_exclusive(namecache_rw_lock);
+}
+
+void
+name_cache_unlock(void)
+{
+ lck_rw_done(namecache_rw_lock);
}
int
resize_namecache(u_int newsize)
{
- struct nchashhead *new_table;
- struct nchashhead *old_table;
- struct nchashhead *old_head, *head;
- struct namecache *entry, *next;
- uint32_t i;
- u_long new_mask, old_mask;
+ struct nchashhead *new_table;
+ struct nchashhead *old_table;
+ struct nchashhead *old_head, *head;
+ struct namecache *entry, *next;
+ uint32_t i, hashval;
+ int dNodes, dNegNodes;
+ u_long new_size, old_size;
+
+ dNegNodes = (newsize / 10);
+ dNodes = newsize + dNegNodes;
// we don't support shrinking yet
- if (newsize < nchash) {
+ if (dNodes <= desiredNodes) {
return 0;
}
+ new_table = hashinit(2 * dNodes, M_CACHE, &nchashmask);
+ new_size = nchashmask + 1;
- new_table = hashinit(newsize, M_CACHE, &new_mask);
if (new_table == NULL) {
return ENOMEM;
}
+ NAME_CACHE_LOCK();
// do the switch!
old_table = nchashtbl;
nchashtbl = new_table;
- old_mask = nchash;
- nchash = new_mask;
+ old_size = nchash;
+ nchash = new_size;
// walk the old table and insert all the entries into
// the new table
//
- for(i=0; i <= old_mask; i++) {
+ for(i=0; i < old_size; i++) {
old_head = &old_table[i];
for (entry=old_head->lh_first; entry != NULL; entry=next) {
//
// XXXdbg - Beware: this assumes that hash_string() does
// the same thing as what happens in
// lookup() over in vfs_lookup.c
- head = NCHHASH(entry->nc_dvp, hash_string(entry->nc_name, 0));
-
+ hashval = hash_string(entry->nc_name, 0);
+ entry->nc_hashval = hashval;
+ head = NCHHASH(entry->nc_dvp, hashval);
+
next = entry->nc_hash.le_next;
LIST_INSERT_HEAD(head, entry, nc_hash);
}
}
+ desiredNodes = dNodes;
+ desiredNegNodes = dNegNodes;
+ NAME_CACHE_UNLOCK();
FREE(old_table, M_CACHE);
return 0;
}
+static void
+cache_delete(struct namecache *ncp, int age_entry)
+{
+ NCHSTAT(ncs_deletes);
+ if (ncp->nc_vp) {
+ LIST_REMOVE(ncp, nc_un.nc_link);
+ } else {
+ TAILQ_REMOVE(&neghead, ncp, nc_un.nc_negentry);
+ ncs_negtotal--;
+ }
+ LIST_REMOVE(ncp, nc_child);
+
+ LIST_REMOVE(ncp, nc_hash);
+ /*
+ * this field is used to indicate
+ * that the entry is in use and
+ * must be deleted before it can
+ * be reused...
+ */
+ ncp->nc_hash.le_prev = NULL;
+
+ if (age_entry) {
+ /*
+ * make it the next one available
+ * for cache_enter's use
+ */
+ TAILQ_REMOVE(&nchead, ncp, nc_entry);
+ TAILQ_INSERT_HEAD(&nchead, ncp, nc_entry);
+ }
+ vfs_removename(ncp->nc_name);
+ ncp->nc_name = NULL;
+}
/*
- * Invalidate a all entries to particular vnode.
- *
- * We actually just increment the v_id, that will do it. The entries will
- * be purged by lookup as they get found. If the v_id wraps around, we
- * need to ditch the entire cache, to avoid confusion. No valid vnode will
- * ever have (v_id == 0).
+ * purge the entry associated with the
+ * specified vnode from the name cache
*/
void
-cache_purge(vp)
- struct vnode *vp;
+cache_purge(vnode_t vp)
{
- struct namecache *ncp;
- struct nchashhead *ncpp;
+ struct namecache *ncp;
+ kauth_cred_t tcred = NULL;
- vp->v_id = ++nextvnodeid;
- if (nextvnodeid != 0)
- return;
- for (ncpp = &nchashtbl[nchash]; ncpp >= nchashtbl; ncpp--) {
- while (ncp = ncpp->lh_first)
- PURGE(ncp);
- }
- vp->v_id = ++nextvnodeid;
+ if ((LIST_FIRST(&vp->v_nclinks) == NULL) &&
+ (LIST_FIRST(&vp->v_ncchildren) == NULL) &&
+ (vp->v_cred == NOCRED) &&
+ (vp->v_parent == NULLVP))
+ return;
+
+ NAME_CACHE_LOCK();
+
+ if (vp->v_parent)
+ vp->v_parent->v_nc_generation++;
+
+ while ( (ncp = LIST_FIRST(&vp->v_nclinks)) )
+ cache_delete(ncp, 1);
+
+ while ( (ncp = LIST_FIRST(&vp->v_ncchildren)) )
+ cache_delete(ncp, 1);
+
+ /*
+ * Use a temp variable to avoid kauth_cred_unref() while NAME_CACHE_LOCK is held
+ */
+ tcred = vp->v_cred;
+ vp->v_cred = NOCRED;
+ vp->v_authorized_actions = 0;
+
+ NAME_CACHE_UNLOCK();
+
+ if (IS_VALID_CRED(tcred))
+ kauth_cred_unref(&tcred);
+}
+
+/*
+ * Purge all negative cache entries that are children of the
+ * given vnode. A case-insensitive file system (or any file
+ * system that has multiple equivalent names for the same
+ * directory entry) can use this when creating or renaming
+ * to remove negative entries that may no longer apply.
+ */
+void
+cache_purge_negatives(vnode_t vp)
+{
+ struct namecache *ncp, *next_ncp;
+
+ NAME_CACHE_LOCK();
+
+ LIST_FOREACH_SAFE(ncp, &vp->v_ncchildren, nc_child, next_ncp)
+ if (ncp->nc_vp == NULL)
+ cache_delete(ncp , 1);
+
+ NAME_CACHE_UNLOCK();
}
/*
* Flush all entries referencing a particular filesystem.
*
* Since we need to check it anyway, we will flush all the invalid
- * entriess at the same time.
+ * entries at the same time.
*/
void
-cache_purgevfs(mp)
- struct mount *mp;
+cache_purgevfs(struct mount *mp)
{
struct nchashhead *ncpp;
- struct namecache *ncp, *nnp;
+ struct namecache *ncp;
+ NAME_CACHE_LOCK();
/* Scan hash tables for applicable entries */
- for (ncpp = &nchashtbl[nchash]; ncpp >= nchashtbl; ncpp--) {
- for (ncp = ncpp->lh_first; ncp != 0; ncp = nnp) {
- nnp = ncp->nc_hash.le_next;
- if (ncp->nc_dvpid != ncp->nc_dvp->v_id ||
- (ncp->nc_vp && ncp->nc_vpid != ncp->nc_vp->v_id) ||
- ncp->nc_dvp->v_mount == mp) {
- PURGE(ncp);
+ for (ncpp = &nchashtbl[nchash - 1]; ncpp >= nchashtbl; ncpp--) {
+restart:
+ for (ncp = ncpp->lh_first; ncp != 0; ncp = ncp->nc_hash.le_next) {
+ if (ncp->nc_dvp->v_mount == mp) {
+ cache_delete(ncp, 0);
+ goto restart;
}
}
}
+ NAME_CACHE_UNLOCK();
}
//
static LIST_HEAD(stringhead, string_t) *string_ref_table;
static u_long string_table_mask;
-static uint32_t max_chain_len=0;
-static struct stringhead *long_chain_head=NULL;
static uint32_t filled_buckets=0;
-static uint32_t num_dups=0;
-static uint32_t nstrings=0;
+
typedef struct string_t {
LIST_ENTRY(string_t) hash_chain;
- unsigned char *str;
+ const char *str;
uint32_t refcount;
} string_t;
-
-static int
-resize_string_ref_table()
+static void
+resize_string_ref_table(void)
{
- struct stringhead *new_table;
- struct stringhead *old_table;
- struct stringhead *old_head, *head;
- string_t *entry, *next;
- uint32_t i, hashval;
- u_long new_mask, old_mask;
+ struct stringhead *new_table;
+ struct stringhead *old_table;
+ struct stringhead *old_head, *head;
+ string_t *entry, *next;
+ uint32_t i, hashval;
+ u_long new_mask, old_mask;
- new_table = hashinit((string_table_mask + 1) * 2, M_CACHE, &new_mask);
- if (new_table == NULL) {
- return ENOMEM;
- }
+ /*
+ * need to hold the table lock exclusively
+ * in order to grow the table... need to recheck
+ * the need to resize again after we've taken
+ * the lock exclusively in case some other thread
+ * beat us to the punch
+ */
+ lck_rw_lock_exclusive(strtable_rw_lock);
- // do the switch!
- old_table = string_ref_table;
- string_ref_table = new_table;
- old_mask = string_table_mask;
- string_table_mask = new_mask;
+ if (4 * filled_buckets < ((string_table_mask + 1) * 3)) {
+ lck_rw_done(strtable_rw_lock);
+ return;
+ }
+ new_table = hashinit((string_table_mask + 1) * 2, M_CACHE, &new_mask);
- printf("resize: max chain len %d, new table size %d\n",
- max_chain_len, new_mask + 1);
- max_chain_len = 0;
- long_chain_head = NULL;
- filled_buckets = 0;
+ if (new_table == NULL) {
+ printf("failed to resize the hash table.\n");
+ lck_rw_done(strtable_rw_lock);
+ return;
+ }
- // walk the old table and insert all the entries into
- // the new table
- //
- for(i=0; i <= old_mask; i++) {
- old_head = &old_table[i];
- for (entry=old_head->lh_first; entry != NULL; entry=next) {
- hashval = hash_string(entry->str, 0);
- head = &string_ref_table[hashval & string_table_mask];
- if (head->lh_first == NULL) {
- filled_buckets++;
- }
+ // do the switch!
+ old_table = string_ref_table;
+ string_ref_table = new_table;
+ old_mask = string_table_mask;
+ string_table_mask = new_mask;
+ filled_buckets = 0;
- next = entry->hash_chain.le_next;
- LIST_INSERT_HEAD(head, entry, hash_chain);
+ // walk the old table and insert all the entries into
+ // the new table
+ //
+ for (i = 0; i <= old_mask; i++) {
+ old_head = &old_table[i];
+ for (entry = old_head->lh_first; entry != NULL; entry = next) {
+ hashval = hash_string((const char *)entry->str, 0);
+ head = &string_ref_table[hashval & string_table_mask];
+ if (head->lh_first == NULL) {
+ filled_buckets++;
+ }
+ next = entry->hash_chain.le_next;
+ LIST_INSERT_HEAD(head, entry, hash_chain);
+ }
}
- }
-
- FREE(old_table, M_CACHE);
+ lck_rw_done(strtable_rw_lock);
- return 0;
+ FREE(old_table, M_CACHE);
}
static void
init_string_table(void)
{
- string_ref_table = hashinit(4096, M_CACHE, &string_table_mask);
+ string_ref_table = hashinit(CONFIG_VFS_NAMES, M_CACHE, &string_table_mask);
}
-char *
-add_name(const char *name, size_t len, u_int hashval, u_int flags)
+const char *
+vfs_addname(const char *name, uint32_t len, u_int hashval, u_int flags)
{
- struct stringhead *head;
- string_t *entry;
- int chain_len = 0;
-
- //
- // If the table gets more than 3/4 full, resize it
- //
- if (4*filled_buckets >= ((string_table_mask + 1) * 3)) {
- if (resize_string_ref_table() != 0) {
- printf("failed to resize the hash table.\n");
- }
- }
+ return (add_name_internal(name, len, hashval, FALSE, flags));
+}
- if (hashval == 0) {
- hashval = hash_string(name, len);
- }
- head = &string_ref_table[hashval & string_table_mask];
- for (entry=head->lh_first; entry != NULL; chain_len++, entry=entry->hash_chain.le_next) {
- if (strncmp(entry->str, name, len) == 0 && entry->str[len] == '\0') {
- entry->refcount++;
- num_dups++;
- break;
+static const char *
+add_name_internal(const char *name, uint32_t len, u_int hashval, boolean_t need_extra_ref, __unused u_int flags)
+{
+ struct stringhead *head;
+ string_t *entry;
+ uint32_t chain_len = 0;
+ uint32_t hash_index;
+ uint32_t lock_index;
+ char *ptr;
+
+ /*
+ * if the length already accounts for the null-byte, then
+ * subtract one so later on we don't index past the end
+ * of the string.
+ */
+ if (len > 0 && name[len-1] == '\0') {
+ len--;
+ }
+ if (hashval == 0) {
+ hashval = hash_string(name, len);
}
- }
- if (entry == NULL) {
- // it wasn't already there so add it.
- MALLOC(entry, string_t *, sizeof(string_t) + len + 1, M_TEMP, M_WAITOK);
+ /*
+ * take this lock 'shared' to keep the hash stable
+ * if someone else decides to grow the pool they
+ * will take this lock exclusively
+ */
+ lck_rw_lock_shared(strtable_rw_lock);
- // have to get "head" again because we could have blocked
- // in malloc and thus head could have changed.
- //
- head = &string_ref_table[hashval & string_table_mask];
- if (head->lh_first == NULL) {
- filled_buckets++;
+ /*
+ * If the table gets more than 3/4 full, resize it
+ */
+ if (4 * filled_buckets >= ((string_table_mask + 1) * 3)) {
+ lck_rw_done(strtable_rw_lock);
+
+ resize_string_ref_table();
+
+ lck_rw_lock_shared(strtable_rw_lock);
}
+ hash_index = hashval & string_table_mask;
+ lock_index = hash_index % NUM_STRCACHE_LOCKS;
+
+ head = &string_ref_table[hash_index];
- LIST_INSERT_HEAD(head, entry, hash_chain);
- entry->str = (char *)((char *)entry + sizeof(string_t));
- strncpy(entry->str, name, len);
- entry->str[len] = '\0';
- entry->refcount = 1;
+ lck_mtx_lock_spin(&strcache_mtx_locks[lock_index]);
- if (chain_len > max_chain_len) {
- max_chain_len = chain_len;
- long_chain_head = head;
+ for (entry = head->lh_first; entry != NULL; chain_len++, entry = entry->hash_chain.le_next) {
+ if (memcmp(entry->str, name, len) == 0 && entry->str[len] == 0) {
+ entry->refcount++;
+ break;
+ }
}
+ if (entry == NULL) {
+ lck_mtx_convert_spin(&strcache_mtx_locks[lock_index]);
+ /*
+ * it wasn't already there so add it.
+ */
+ MALLOC(entry, string_t *, sizeof(string_t) + len + 1, M_TEMP, M_WAITOK);
- nstrings++;
- }
+ if (head->lh_first == NULL) {
+ OSAddAtomic(1, &filled_buckets);
+ }
+ ptr = (char *)((char *)entry + sizeof(string_t));
+ strncpy(ptr, name, len);
+ ptr[len] = '\0';
+ entry->str = ptr;
+ entry->refcount = 1;
+ LIST_INSERT_HEAD(head, entry, hash_chain);
+ }
+ if (need_extra_ref == TRUE)
+ entry->refcount++;
- return entry->str;
+ lck_mtx_unlock(&strcache_mtx_locks[lock_index]);
+ lck_rw_done(strtable_rw_lock);
+
+ return (const char *)entry->str;
}
+
int
-remove_name(const char *nameref)
+vfs_removename(const char *nameref)
{
- struct stringhead *head;
- string_t *entry;
- uint32_t hashval;
-
- hashval = hash_string(nameref, 0);
- head = &string_ref_table[hashval & string_table_mask];
- for (entry=head->lh_first; entry != NULL; entry=entry->hash_chain.le_next) {
- if (entry->str == (unsigned char *)nameref) {
- entry->refcount--;
- if (entry->refcount == 0) {
- LIST_REMOVE(entry, hash_chain);
- if (head->lh_first == NULL) {
- filled_buckets--;
- }
- entry->str = NULL;
- nstrings--;
+ struct stringhead *head;
+ string_t *entry;
+ uint32_t hashval;
+ uint32_t hash_index;
+ uint32_t lock_index;
+ int retval = ENOENT;
- FREE(entry, M_TEMP);
- } else {
- num_dups--;
- }
+ hashval = hash_string(nameref, 0);
+
+ /*
+ * take this lock 'shared' to keep the hash stable
+ * if someone else decides to grow the pool they
+ * will take this lock exclusively
+ */
+ lck_rw_lock_shared(strtable_rw_lock);
+ /*
+ * must compute the head behind the table lock
+ * since the size and location of the table
+ * can change on the fly
+ */
+ hash_index = hashval & string_table_mask;
+ lock_index = hash_index % NUM_STRCACHE_LOCKS;
+
+ head = &string_ref_table[hash_index];
+
+ lck_mtx_lock_spin(&strcache_mtx_locks[lock_index]);
+
+ for (entry = head->lh_first; entry != NULL; entry = entry->hash_chain.le_next) {
+ if (entry->str == nameref) {
+ entry->refcount--;
+
+ if (entry->refcount == 0) {
+ LIST_REMOVE(entry, hash_chain);
- return 0;
+ if (head->lh_first == NULL) {
+ OSAddAtomic(-1, &filled_buckets);
+ }
+ } else {
+ entry = NULL;
+ }
+ retval = 0;
+ break;
+ }
}
- }
+ lck_mtx_unlock(&strcache_mtx_locks[lock_index]);
+ lck_rw_done(strtable_rw_lock);
- return ENOENT;
+ if (entry != NULL)
+ FREE(entry, M_TEMP);
+
+ return retval;
}
+#ifdef DUMP_STRING_TABLE
void
dump_string_table(void)
{
struct stringhead *head;
string_t *entry;
- int i;
+ u_long i;
- for(i=0; i <= string_table_mask; i++) {
+ lck_rw_lock_shared(strtable_rw_lock);
+
+ for (i = 0; i <= string_table_mask; i++) {
head = &string_ref_table[i];
for (entry=head->lh_first; entry != NULL; entry=entry->hash_chain.le_next) {
printf("%6d - %s\n", entry->refcount, entry->str);
}
}
+ lck_rw_done(strtable_rw_lock);
}
+#endif /* DUMP_STRING_TABLE */
projects / apple / xnu.git / blobdiff