pseudofs_fileno.c revision 168720 
1/*-
2 * Copyright (c) 2001 Dag-Erling Co�dan Sm�rgrav
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/sys/fs/pseudofs/pseudofs_fileno.c 168720 2007-04-14 14:08:30Z des $");
31
32#include "opt_pseudofs.h"
33
34#include <sys/param.h>
35#include <sys/kernel.h>
36#include <sys/systm.h>
37#include <sys/limits.h>
38#include <sys/lock.h>
39#include <sys/malloc.h>
40#include <sys/mutex.h>
41#include <sys/proc.h>
42#include <sys/sysctl.h>
43#include <sys/systm.h>
44
45#include <fs/pseudofs/pseudofs.h>
46#include <fs/pseudofs/pseudofs_internal.h>
47
48/*
49 * Initialize fileno bitmap
50 */
51void
52pfs_fileno_init(struct pfs_info *pi)
53{
54
55	mtx_assert(&Giant, MA_OWNED);
56	mtx_init(&pi->pi_mutex, "pfs_fileno", NULL, MTX_DEF);
57	pi->pi_unrhdr = new_unrhdr(3, INT_MAX / NO_PID, &pi->pi_mutex);
58}
59
60/*
61 * Tear down fileno bitmap
62 */
63void
64pfs_fileno_uninit(struct pfs_info *pi)
65{
66
67	mtx_assert(&Giant, MA_OWNED);
68	delete_unrhdr(pi->pi_unrhdr);
69	pi->pi_unrhdr = NULL;
70	mtx_destroy(&pi->pi_mutex);
71}
72
73/*
74 * Allocate a file number
75 */
76void
77pfs_fileno_alloc(struct pfs_node *pn)
78{
79
80	/* make sure our parent has a file number */
81	if (pn->pn_parent && !pn->pn_parent->pn_fileno)
82		pfs_fileno_alloc(pn->pn_parent);
83
84	switch (pn->pn_type) {
85	case pfstype_root:
86		/* root must always be 2 */
87		pn->pn_fileno = 2;
88		break;
89	case pfstype_dir:
90	case pfstype_file:
91	case pfstype_symlink:
92	case pfstype_procdir:
93		pn->pn_fileno = alloc_unr(pn->pn_info->pi_unrhdr);
94		break;
95	case pfstype_this:
96		KASSERT(pn->pn_parent != NULL,
97		    ("pfstype_this node has no parent"));
98		pn->pn_fileno = pn->pn_parent->pn_fileno;
99		break;
100	case pfstype_parent:
101		KASSERT(pn->pn_parent != NULL,
102		    ("pfstype_parent node has no parent"));
103		if (pn->pn_parent == pn->pn_info->pi_root) {
104			pn->pn_fileno = pn->pn_parent->pn_fileno;
105			break;
106		}
107		KASSERT(pn->pn_parent->pn_parent != NULL,
108		    ("pfstype_parent node has no grandparent"));
109		pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno;
110		break;
111	case pfstype_none:
112		KASSERT(0,
113		    ("pfs_fileno_alloc() called for pfstype_none node"));
114		break;
115	}
116
117#if 0
118	printf("pfs_fileno_alloc(): %s: ", pn->pn_info->pi_name);
119	if (pn->pn_parent) {
120		if (pn->pn_parent->pn_parent) {
121			printf("%s/", pn->pn_parent->pn_parent->pn_name);
122		}
123		printf("%s/", pn->pn_parent->pn_name);
124	}
125	printf("%s -> %d\n", pn->pn_name, pn->pn_fileno);
126#endif
127}
128
129/*
130 * Release a file number
131 */
132void
133pfs_fileno_free(struct pfs_node *pn)
134{
135
136	switch (pn->pn_type) {
137	case pfstype_root:
138		/* not allocated from unrhdr */
139		return;
140	case pfstype_dir:
141	case pfstype_file:
142	case pfstype_symlink:
143	case pfstype_procdir:
144		free_unr(pn->pn_info->pi_unrhdr, pn->pn_fileno);
145		break;
146	case pfstype_this:
147	case pfstype_parent:
148		/* ignore these, as they don't "own" their file number */
149		break;
150	case pfstype_none:
151		KASSERT(0,
152		    ("pfs_fileno_free() called for pfstype_none node"));
153		break;
154	}
155}
156