583 lines
13 KiB
C
583 lines
13 KiB
C
/* $NetBSD: kern_fileassoc.c,v 1.24 2007/02/08 16:06:58 elad Exp $ */
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/*-
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* Copyright (c) 2006 Elad Efrat <elad@NetBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_fileassoc.c,v 1.24 2007/02/08 16:06:58 elad Exp $");
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#include "opt_fileassoc.h"
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#include <sys/param.h>
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#include <sys/mount.h>
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#include <sys/queue.h>
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#include <sys/malloc.h>
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#include <sys/vnode.h>
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#include <sys/namei.h>
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#include <sys/exec.h>
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#include <sys/proc.h>
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#include <sys/inttypes.h>
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#include <sys/errno.h>
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#include <sys/fileassoc.h>
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#include <sys/specificdata.h>
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#include <sys/hash.h>
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#include <sys/fstypes.h>
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#include <sys/kmem.h>
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#include <sys/once.h>
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#define FILEASSOC_INITIAL_TABLESIZE 128
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static struct fileassoc_hash_entry *
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fileassoc_file_lookup(struct vnode *, fhandle_t *);
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static struct fileassoc_hash_entry *
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fileassoc_file_add(struct vnode *, fhandle_t *);
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static struct fileassoc_table *fileassoc_table_resize(struct fileassoc_table *);
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static specificdata_domain_t fileassoc_domain;
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static specificdata_key_t fileassoc_mountspecific_key;
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/*
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* Hook entry.
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* Includes the hook name for identification and private hook clear callback.
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*/
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struct fileassoc {
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LIST_ENTRY(fileassoc) list;
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const char *name; /* name. */
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fileassoc_cleanup_cb_t cleanup_cb; /* clear callback. */
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specificdata_key_t key;
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};
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static LIST_HEAD(, fileassoc) fileassoc_list;
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/* An entry in the per-mount hash table. */
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struct fileassoc_hash_entry {
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fhandle_t *handle; /* File handle */
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specificdata_reference data; /* Hooks. */
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u_int nassocs; /* # of hooks. */
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LIST_ENTRY(fileassoc_hash_entry) entries; /* List pointer. */
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};
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LIST_HEAD(fileassoc_hashhead, fileassoc_hash_entry);
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struct fileassoc_table {
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struct fileassoc_hashhead *hash_tbl;
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size_t hash_size; /* Number of slots. */
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u_long hash_mask;
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size_t hash_used; /* # of used slots. */
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specificdata_reference data;
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};
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/*
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* Hashing function: Takes a number modulus the mask to give back an
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* index into the hash table.
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*/
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#define FILEASSOC_HASH(tbl, handle) \
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(hash32_buf((handle), FHANDLE_SIZE(handle), HASH32_BUF_INIT) \
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& ((tbl)->hash_mask))
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static void *
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file_getdata(struct fileassoc_hash_entry *e, const struct fileassoc *assoc)
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{
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return specificdata_getspecific(fileassoc_domain, &e->data,
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assoc->key);
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}
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static void
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file_setdata(struct fileassoc_hash_entry *e, const struct fileassoc *assoc,
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void *data)
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{
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specificdata_setspecific(fileassoc_domain, &e->data, assoc->key,
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data);
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}
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static void
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file_cleanup(struct fileassoc_hash_entry *e, const struct fileassoc *assoc)
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{
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fileassoc_cleanup_cb_t cb;
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void *data;
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cb = assoc->cleanup_cb;
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if (cb == NULL) {
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return;
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}
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data = file_getdata(e, assoc);
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(*cb)(data);
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}
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static void
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file_free(struct fileassoc_hash_entry *e)
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{
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struct fileassoc *assoc;
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LIST_REMOVE(e, entries);
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LIST_FOREACH(assoc, &fileassoc_list, list) {
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file_cleanup(e, assoc);
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}
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vfs_composefh_free(e->handle);
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specificdata_fini(fileassoc_domain, &e->data);
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kmem_free(e, sizeof(*e));
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}
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static void
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table_dtor(void *vp)
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{
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struct fileassoc_table *tbl = vp;
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struct fileassoc_hashhead *hh;
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u_long i;
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/* Remove all entries from the table and lists */
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hh = tbl->hash_tbl;
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for (i = 0; i < tbl->hash_size; i++) {
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struct fileassoc_hash_entry *mhe;
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while ((mhe = LIST_FIRST(&hh[i])) != NULL) {
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file_free(mhe);
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}
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}
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/* Remove hash table and sysctl node */
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hashdone(tbl->hash_tbl, M_TEMP);
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specificdata_fini(fileassoc_domain, &tbl->data);
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kmem_free(tbl, sizeof(*tbl));
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}
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/*
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* Initialize the fileassoc subsystem.
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*/
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static int
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fileassoc_init(void)
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{
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int error;
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error = mount_specific_key_create(&fileassoc_mountspecific_key,
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table_dtor);
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if (error) {
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return error;
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}
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fileassoc_domain = specificdata_domain_create();
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return 0;
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}
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/*
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* Register a new hook.
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*/
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int
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fileassoc_register(const char *name, fileassoc_cleanup_cb_t cleanup_cb,
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fileassoc_t *result)
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{
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int error;
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specificdata_key_t key;
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struct fileassoc *assoc;
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static ONCE_DECL(control);
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error = RUN_ONCE(&control, fileassoc_init);
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if (error) {
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return error;
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}
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error = specificdata_key_create(fileassoc_domain, &key, NULL);
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if (error) {
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return error;
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}
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assoc = kmem_alloc(sizeof(*assoc), KM_SLEEP);
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assoc->name = name;
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assoc->cleanup_cb = cleanup_cb;
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assoc->key = key;
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LIST_INSERT_HEAD(&fileassoc_list, assoc, list);
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*result = assoc;
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return 0;
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}
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/*
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* Deregister a hook.
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*/
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int
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fileassoc_deregister(fileassoc_t assoc)
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{
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LIST_REMOVE(assoc, list);
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specificdata_key_delete(fileassoc_domain, assoc->key);
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kmem_free(assoc, sizeof(*assoc));
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return 0;
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}
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/*
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* Get the hash table for the specified device.
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*/
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static struct fileassoc_table *
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fileassoc_table_lookup(struct mount *mp)
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{
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return mount_getspecific(mp, fileassoc_mountspecific_key);
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}
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/*
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* Perform a lookup on a hash table. If hint is non-zero then use the value
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* of the hint as the identifier instead of performing a lookup for the
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* fileid.
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*/
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static struct fileassoc_hash_entry *
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fileassoc_file_lookup(struct vnode *vp, fhandle_t *hint)
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{
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struct fileassoc_table *tbl;
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struct fileassoc_hashhead *tble;
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struct fileassoc_hash_entry *e;
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size_t indx;
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fhandle_t *th;
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int error;
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tbl = fileassoc_table_lookup(vp->v_mount);
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if (tbl == NULL) {
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return NULL;
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}
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if (hint == NULL) {
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error = vfs_composefh_alloc(vp, &th);
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if (error)
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return (NULL);
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} else {
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th = hint;
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}
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indx = FILEASSOC_HASH(tbl, th);
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tble = &(tbl->hash_tbl[indx]);
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LIST_FOREACH(e, tble, entries) {
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if (((FHANDLE_FILEID(e->handle)->fid_len ==
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FHANDLE_FILEID(th)->fid_len)) &&
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(memcmp(FHANDLE_FILEID(e->handle), FHANDLE_FILEID(th),
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(FHANDLE_FILEID(th))->fid_len) == 0)) {
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break;
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}
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}
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if (hint == NULL)
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vfs_composefh_free(th);
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return e;
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}
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/*
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* Return hook data associated with a vnode.
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*/
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void *
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fileassoc_lookup(struct vnode *vp, fileassoc_t assoc)
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{
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struct fileassoc_hash_entry *mhe;
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mhe = fileassoc_file_lookup(vp, NULL);
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if (mhe == NULL)
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return (NULL);
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return file_getdata(mhe, assoc);
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}
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static struct fileassoc_table *
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fileassoc_table_resize(struct fileassoc_table *tbl)
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{
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struct fileassoc_table *newtbl;
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struct fileassoc_hashhead *hh;
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u_long i;
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/*
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* Allocate a new table. Like the condition in fileassoc_file_add(),
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* this is also temporary -- just double the number of slots.
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*/
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newtbl = kmem_zalloc(sizeof(*newtbl), KM_SLEEP);
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newtbl->hash_size = (tbl->hash_size * 2);
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if (newtbl->hash_size < tbl->hash_size)
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newtbl->hash_size = tbl->hash_size;
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newtbl->hash_tbl = hashinit(newtbl->hash_size, HASH_LIST, M_TEMP,
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M_WAITOK | M_ZERO, &newtbl->hash_mask);
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newtbl->hash_used = 0;
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specificdata_init(fileassoc_domain, &newtbl->data);
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/* XXX we need to make sure nothing uses fileassoc here! */
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hh = tbl->hash_tbl;
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for (i = 0; i < tbl->hash_size; i++) {
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struct fileassoc_hash_entry *mhe;
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while ((mhe = LIST_FIRST(&hh[i])) != NULL) {
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struct fileassoc_hashhead *vhh;
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size_t indx;
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LIST_REMOVE(mhe, entries);
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indx = FILEASSOC_HASH(newtbl, mhe->handle);
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vhh = &(newtbl->hash_tbl[indx]);
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LIST_INSERT_HEAD(vhh, mhe, entries);
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newtbl->hash_used++;
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}
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}
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if (tbl->hash_used != newtbl->hash_used)
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panic("fileassoc_table_resize: inconsistency detected! "
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"needed %zu entries, got %zu", tbl->hash_used,
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newtbl->hash_used);
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hashdone(tbl->hash_tbl, M_TEMP);
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specificdata_fini(fileassoc_domain, &tbl->data);
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kmem_free(tbl, sizeof(*tbl));
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return (newtbl);
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}
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/*
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* Create a new fileassoc table.
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*/
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static struct fileassoc_table *
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fileassoc_table_add(struct mount *mp)
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{
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struct fileassoc_table *tbl;
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/* Check for existing table for device. */
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tbl = fileassoc_table_lookup(mp);
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if (tbl != NULL)
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return (tbl);
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/* Allocate and initialize a table. */
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tbl = kmem_zalloc(sizeof(*tbl), KM_SLEEP);
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tbl->hash_size = FILEASSOC_INITIAL_TABLESIZE;
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tbl->hash_tbl = hashinit(tbl->hash_size, HASH_LIST, M_TEMP,
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M_WAITOK | M_ZERO, &tbl->hash_mask);
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tbl->hash_used = 0;
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specificdata_init(fileassoc_domain, &tbl->data);
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mount_setspecific(mp, fileassoc_mountspecific_key, tbl);
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return (tbl);
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}
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/*
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* Delete a table.
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*/
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int
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fileassoc_table_delete(struct mount *mp)
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{
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struct fileassoc_table *tbl;
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tbl = fileassoc_table_lookup(mp);
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if (tbl == NULL)
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return (EEXIST);
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mount_setspecific(mp, fileassoc_mountspecific_key, NULL);
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table_dtor(tbl);
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return (0);
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}
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/*
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* Run a callback for each hook entry in a table.
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*/
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int
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fileassoc_table_run(struct mount *mp, fileassoc_t assoc, fileassoc_cb_t cb)
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{
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struct fileassoc_table *tbl;
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struct fileassoc_hashhead *hh;
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u_long i;
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tbl = fileassoc_table_lookup(mp);
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if (tbl == NULL)
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return (EEXIST);
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hh = tbl->hash_tbl;
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for (i = 0; i < tbl->hash_size; i++) {
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struct fileassoc_hash_entry *mhe;
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LIST_FOREACH(mhe, &hh[i], entries) {
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void *data;
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data = file_getdata(mhe, assoc);
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if (data != NULL)
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cb(data);
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}
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}
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return (0);
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}
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/*
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* Clear a table for a given hook.
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*/
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int
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fileassoc_table_clear(struct mount *mp, fileassoc_t assoc)
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{
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struct fileassoc_table *tbl;
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struct fileassoc_hashhead *hh;
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u_long i;
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tbl = fileassoc_table_lookup(mp);
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if (tbl == NULL)
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return (EEXIST);
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hh = tbl->hash_tbl;
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for (i = 0; i < tbl->hash_size; i++) {
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struct fileassoc_hash_entry *mhe;
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LIST_FOREACH(mhe, &hh[i], entries) {
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file_cleanup(mhe, assoc);
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file_setdata(mhe, assoc, NULL);
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}
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}
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return (0);
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}
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/*
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* Add a file entry to a table.
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*/
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static struct fileassoc_hash_entry *
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fileassoc_file_add(struct vnode *vp, fhandle_t *hint)
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{
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struct fileassoc_table *tbl;
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struct fileassoc_hashhead *vhh;
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struct fileassoc_hash_entry *e;
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size_t indx;
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fhandle_t *th;
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int error;
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if (hint == NULL) {
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error = vfs_composefh_alloc(vp, &th);
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if (error)
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return (NULL);
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} else
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th = hint;
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e = fileassoc_file_lookup(vp, th);
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if (e != NULL) {
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if (hint == NULL)
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vfs_composefh_free(th);
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return (e);
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}
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tbl = fileassoc_table_lookup(vp->v_mount);
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if (tbl == NULL) {
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tbl = fileassoc_table_add(vp->v_mount);
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}
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indx = FILEASSOC_HASH(tbl, th);
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vhh = &(tbl->hash_tbl[indx]);
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e = kmem_zalloc(sizeof(*e), KM_SLEEP);
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e->handle = th;
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specificdata_init(fileassoc_domain, &e->data);
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LIST_INSERT_HEAD(vhh, e, entries);
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/*
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* This decides when we need to resize the table. For now,
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* resize it whenever we "filled" up the number of slots it
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* has. That's not really true unless of course we had zero
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* collisions. Think positive! :)
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*/
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if (++(tbl->hash_used) == tbl->hash_size) {
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struct fileassoc_table *newtbl;
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newtbl = fileassoc_table_resize(tbl);
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mount_setspecific(vp->v_mount, fileassoc_mountspecific_key,
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newtbl);
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}
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return (e);
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}
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/*
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* Delete a file entry from a table.
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*/
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int
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fileassoc_file_delete(struct vnode *vp)
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{
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struct fileassoc_table *tbl;
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struct fileassoc_hash_entry *mhe;
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mhe = fileassoc_file_lookup(vp, NULL);
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if (mhe == NULL)
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return (ENOENT);
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file_free(mhe);
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tbl = fileassoc_table_lookup(vp->v_mount);
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--(tbl->hash_used); /* XXX gc? */
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return (0);
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}
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/*
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* Add a hook to a vnode.
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*/
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int
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fileassoc_add(struct vnode *vp, fileassoc_t assoc, void *data)
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{
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struct fileassoc_hash_entry *e;
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void *olddata;
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e = fileassoc_file_lookup(vp, NULL);
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if (e == NULL) {
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e = fileassoc_file_add(vp, NULL);
|
|
if (e == NULL)
|
|
return (ENOTDIR);
|
|
}
|
|
|
|
olddata = file_getdata(e, assoc);
|
|
if (olddata != NULL)
|
|
return (EEXIST);
|
|
|
|
file_setdata(e, assoc, data);
|
|
|
|
e->nassocs++;
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Clear a hook from a vnode.
|
|
*/
|
|
int
|
|
fileassoc_clear(struct vnode *vp, fileassoc_t assoc)
|
|
{
|
|
struct fileassoc_hash_entry *mhe;
|
|
|
|
mhe = fileassoc_file_lookup(vp, NULL);
|
|
if (mhe == NULL)
|
|
return (ENOENT);
|
|
|
|
file_cleanup(mhe, assoc);
|
|
file_setdata(mhe, assoc, NULL);
|
|
|
|
--(mhe->nassocs); /* XXX gc? */
|
|
|
|
return (0);
|
|
}
|