xref: /freebsd/sys/fs/pseudofs/pseudofs_fileno.c (revision 3fc36ee018bb836bd1796067cf4ef8683f166ebc)
1 /*-
2  * Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
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("$FreeBSD$");
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  */
51 void
52 pfs_fileno_init(struct pfs_info *pi)
53 {
54 
55 	mtx_init(&pi->pi_mutex, "pfs_fileno", NULL, MTX_DEF);
56 	pi->pi_unrhdr = new_unrhdr(3, INT_MAX / NO_PID, &pi->pi_mutex);
57 }
58 
59 /*
60  * Tear down fileno bitmap
61  */
62 void
63 pfs_fileno_uninit(struct pfs_info *pi)
64 {
65 
66 	delete_unrhdr(pi->pi_unrhdr);
67 	pi->pi_unrhdr = NULL;
68 	mtx_destroy(&pi->pi_mutex);
69 }
70 
71 /*
72  * Allocate a file number
73  */
74 void
75 pfs_fileno_alloc(struct pfs_node *pn)
76 {
77 
78 	if (pn->pn_parent)
79 		PFS_TRACE(("%s/%s", pn->pn_parent->pn_name, pn->pn_name));
80 	else
81 		PFS_TRACE(("%s", pn->pn_name));
82 	pfs_assert_not_owned(pn);
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 		    ("%s(): pfstype_this node has no parent", __func__));
98 		pn->pn_fileno = pn->pn_parent->pn_fileno;
99 		break;
100 	case pfstype_parent:
101 		KASSERT(pn->pn_parent != NULL,
102 		    ("%s(): pfstype_parent node has no parent", __func__));
103 		if (pn->pn_parent->pn_type == pfstype_root) {
104 			pn->pn_fileno = pn->pn_parent->pn_fileno;
105 			break;
106 		}
107 		KASSERT(pn->pn_parent->pn_parent != NULL,
108 		    ("%s(): pfstype_parent node has no grandparent", __func__));
109 		pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno;
110 		break;
111 	case pfstype_none:
112 		KASSERT(0,
113 		    ("%s(): pfstype_none node", __func__));
114 		break;
115 	}
116 
117 #if 0
118 	printf("%s(): %s: ", __func__, 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  */
132 void
133 pfs_fileno_free(struct pfs_node *pn)
134 {
135 
136 	pfs_assert_not_owned(pn);
137 
138 	switch (pn->pn_type) {
139 	case pfstype_root:
140 		/* not allocated from unrhdr */
141 		return;
142 	case pfstype_dir:
143 	case pfstype_file:
144 	case pfstype_symlink:
145 	case pfstype_procdir:
146 		free_unr(pn->pn_info->pi_unrhdr, pn->pn_fileno);
147 		break;
148 	case pfstype_this:
149 	case pfstype_parent:
150 		/* ignore these, as they don't "own" their file number */
151 		break;
152 	case pfstype_none:
153 		KASSERT(0,
154 		    ("pfs_fileno_free() called for pfstype_none node"));
155 		break;
156 	}
157 }
158