pseudofs_fileno.c revision 168637 
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 168637 2007-04-11 22:40:57Z 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/sysctl.h>
42#include <sys/systm.h>
43
44#include <fs/pseudofs/pseudofs.h>
45#include <fs/pseudofs/pseudofs_internal.h>
46
47/*
48 * Initialize fileno bitmap
49 */
50void
51pfs_fileno_init(struct pfs_info *pi)
52{
53	struct unrhdr *up;
54
55	up = new_unrhdr(3, INT_MAX, &pi->pi_mutex);
56	mtx_lock(&pi->pi_mutex);
57	pi->pi_unrhdr = up;
58	mtx_unlock(&pi->pi_mutex);
59}
60
61/*
62 * Tear down fileno bitmap
63 */
64void
65pfs_fileno_uninit(struct pfs_info *pi)
66{
67	struct unrhdr *up;
68
69	mtx_lock(&pi->pi_mutex);
70
71	up = pi->pi_unrhdr;
72	pi->pi_unrhdr = NULL;
73
74	mtx_unlock(&pi->pi_mutex);
75
76	delete_unrhdr(up);
77}
78
79/*
80 * Allocate a file number
81 */
82void
83pfs_fileno_alloc(struct pfs_info *pi, struct pfs_node *pn)
84{
85	/* pi is not really necessary as it can be derived */
86	KASSERT(pi == pn->pn_info, ("pn / pi mismatch"));
87
88	/* make sure our parent has a file number */
89	if (pn->pn_parent && !pn->pn_parent->pn_fileno)
90		pfs_fileno_alloc(pi, pn->pn_parent);
91
92	switch (pn->pn_type) {
93	case pfstype_root:
94		/* root must always be 2 */
95		pn->pn_fileno = 2;
96		break;
97	case pfstype_dir:
98	case pfstype_file:
99	case pfstype_symlink:
100	case pfstype_procdir:
101		pn->pn_fileno = alloc_unr(pi->pi_unrhdr);
102		break;
103	case pfstype_this:
104		KASSERT(pn->pn_parent != NULL,
105		    ("pfstype_this node has no parent"));
106		pn->pn_fileno = pn->pn_parent->pn_fileno;
107		break;
108	case pfstype_parent:
109		KASSERT(pn->pn_parent != NULL,
110		    ("pfstype_parent node has no parent"));
111		if (pn->pn_parent == pi->pi_root) {
112			pn->pn_fileno = pn->pn_parent->pn_fileno;
113			break;
114		}
115		KASSERT(pn->pn_parent->pn_parent != NULL,
116		    ("pfstype_parent node has no grandparent"));
117		pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno;
118		break;
119	case pfstype_none:
120		KASSERT(0,
121		    ("pfs_fileno_alloc() called for pfstype_none node"));
122		break;
123	}
124
125#if 0
126	printf("pfs_fileno_alloc(): %s: ", pi->pi_name);
127	if (pn->pn_parent) {
128		if (pn->pn_parent->pn_parent) {
129			printf("%s/", pn->pn_parent->pn_parent->pn_name);
130		}
131		printf("%s/", pn->pn_parent->pn_name);
132	}
133	printf("%s -> %d\n", pn->pn_name, pn->pn_fileno);
134#endif
135}
136
137/*
138 * Release a file number
139 */
140void
141pfs_fileno_free(struct pfs_info *pi, struct pfs_node *pn)
142{
143	/* pi is not really necessary as it can be derived */
144	KASSERT(pi == pn->pn_info, ("pn / pi mismatch"));
145
146	switch (pn->pn_type) {
147	case pfstype_root:
148		/* not allocated from unrhdr */
149		return;
150	case pfstype_dir:
151	case pfstype_file:
152	case pfstype_symlink:
153	case pfstype_procdir:
154		free_unr(pi->pi_unrhdr, pn->pn_fileno);
155		break;
156	case pfstype_this:
157	case pfstype_parent:
158		/* ignore these, as they don't "own" their file number */
159		break;
160	case pfstype_none:
161		KASSERT(0,
162		    ("pfs_fileno_free() called for pfstype_none node"));
163		break;
164	}
165}
166