src/sys/kern/vfs_cwd.c - diff

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Diff for /src/sys/kern/vfs_cwd.c between version 1.1.4.1 and 1.1.4.2

-version 1.1.4.1, 2008/11/18 11:36:58
+version 1.1.4.2, 2008/12/13 01:15:09
-Line 0
+Line 1
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+ /*      $NetBSD$        */
+ /*-
+  * Copyright (c) 2008 The NetBSD Foundation, Inc.
+  * 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.
+  *
+  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+  */
+ /*
+  * Current working directory.
+  */
+ #include <sys/cdefs.h>
+ __KERNEL_RCSID(0, "$NetBSD$");
+ #include <sys/param.h>
+ #include <sys/atomic.h>
+ #include <sys/filedesc.h>
+ #include <sys/proc.h>
+ #include <sys/vnode.h>
+ static int      cwdi_ctor(void *, void *, int);
+ static void     cwdi_dtor(void *, void *);
+ static pool_cache_t cwdi_cache;
+ void
+ cwd_sys_init(void)
+ {
+         cwdi_cache = pool_cache_init(sizeof(struct cwdinfo), coherency_unit,
+, 0, "cwdi", NULL, IPL_NONE, cwdi_ctor, cwdi_dtor, NULL);
+         KASSERT(cwdi_cache != NULL);
+ }
+ /*
+  * Create an initial cwdinfo structure, using the same current and root
+  * directories as curproc.
+  */
+ struct cwdinfo *
+ cwdinit(void)
+ {
+         struct cwdinfo *cwdi;
+         struct cwdinfo *copy;
+         cwdi = pool_cache_get(cwdi_cache, PR_WAITOK);
+         copy = curproc->p_cwdi;
+         rw_enter(&copy->cwdi_lock, RW_READER);
+         cwdi->cwdi_cdir = copy->cwdi_cdir;
+         if (cwdi->cwdi_cdir)
+                 VREF(cwdi->cwdi_cdir);
+         cwdi->cwdi_rdir = copy->cwdi_rdir;
+         if (cwdi->cwdi_rdir)
+                 VREF(cwdi->cwdi_rdir);
+         cwdi->cwdi_edir = copy->cwdi_edir;
+         if (cwdi->cwdi_edir)
+                 VREF(cwdi->cwdi_edir);
+         cwdi->cwdi_cmask =  copy->cwdi_cmask;
+         cwdi->cwdi_refcnt = 1;
+         rw_exit(&copy->cwdi_lock);
+         return (cwdi);
+ }
+ static int
+ cwdi_ctor(void *arg, void *obj, int flags)
+ {
+         struct cwdinfo *cwdi = obj;
+         rw_init(&cwdi->cwdi_lock);
+         return 0;
+ }
+ static void
+ cwdi_dtor(void *arg, void *obj)
+ {
+         struct cwdinfo *cwdi = obj;
+         rw_destroy(&cwdi->cwdi_lock);
+ }
+ /*
+  * Make p2 share p1's cwdinfo.
+  */
+ void
+ cwdshare(struct proc *p2)
+ {
+         struct cwdinfo *cwdi;
+         cwdi = curproc->p_cwdi;
+         atomic_inc_uint(&cwdi->cwdi_refcnt);
+         p2->p_cwdi = cwdi;
+ }
+ /*
+  * Make sure proc has only one reference to its cwdi, creating
+  * a new one if necessary.
+  */
+ void
+ cwdunshare(struct proc *p)
+ {
+         struct cwdinfo *cwdi = p->p_cwdi;
+         if (cwdi->cwdi_refcnt > 1) {
+                 cwdi = cwdinit();
+                 cwdfree(p->p_cwdi);
+                 p->p_cwdi = cwdi;
+         }
+ }
+ /*
+  * Release a cwdinfo structure.
+  */
+ void
+ cwdfree(struct cwdinfo *cwdi)
+ {
+         if (atomic_dec_uint_nv(&cwdi->cwdi_refcnt) > 0)
+                 return;
+         vrele(cwdi->cwdi_cdir);
+         if (cwdi->cwdi_rdir)
+                 vrele(cwdi->cwdi_rdir);
+         if (cwdi->cwdi_edir)
+                 vrele(cwdi->cwdi_edir);
+         pool_cache_put(cwdi_cache, cwdi);
+ }

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