sys/fs/pseudofs/pseudofs_fileno.c

   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_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  */
  63 void
  64 pfs_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  */
  76 void
  77 pfs_fileno_alloc(struct pfs_node *pn)
  78 {
  79
  80         if (pn->pn_parent)
  81                 PFS_TRACE(("%s/%s", pn->pn_parent->pn_name, pn->pn_name));
  82         else
  83                 PFS_TRACE(("%s", pn->pn_name));
  84         pfs_assert_not_owned(pn);
  85
  86         switch (pn->pn_type) {
  87         case pfstype_root:
  88                 /* root must always be 2 */
  89                 pn->pn_fileno = 2;
  90                 break;
  91         case pfstype_dir:
  92         case pfstype_file:
  93         case pfstype_symlink:
  94         case pfstype_procdir:
  95                 pn->pn_fileno = alloc_unr(pn->pn_info->pi_unrhdr);
  96                 break;
  97         case pfstype_this:
  98                 KASSERT(pn->pn_parent != NULL,
  99                     ("%s(): pfstype_this node has no parent", __func__));
 100                 pn->pn_fileno = pn->pn_parent->pn_fileno;
 101                 break;
 102         case pfstype_parent:
 103                 KASSERT(pn->pn_parent != NULL,
 104                     ("%s(): pfstype_parent node has no parent", __func__));
 105                 if (pn->pn_parent->pn_type == pfstype_root) {
 106                         pn->pn_fileno = pn->pn_parent->pn_fileno;
 107                         break;
 108                 }
 109                 KASSERT(pn->pn_parent->pn_parent != NULL,
 110                     ("%s(): pfstype_parent node has no grandparent", __func__));
 111                 pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno;
 112                 break;
 113         case pfstype_none:
 114                 KASSERT(0,
 115                     ("%s(): pfstype_none node", __func__));
 116                 break;
 117         }
 118
 119 #if 0
 120         printf("%s(): %s: ", __func__, pn->pn_info->pi_name);
 121         if (pn->pn_parent) {
 122                 if (pn->pn_parent->pn_parent) {
 123                         printf("%s/", pn->pn_parent->pn_parent->pn_name);
 124                 }
 125                 printf("%s/", pn->pn_parent->pn_name);
 126         }
 127         printf("%s -> %d\n", pn->pn_name, pn->pn_fileno);
 128 #endif
 129 }
 130
 131 /*
 132  * Release a file number
 133  */
 134 void
 135 pfs_fileno_free(struct pfs_node *pn)
 136 {
 137
 138         pfs_assert_not_owned(pn);
 139
 140         switch (pn->pn_type) {
 141         case pfstype_root:
 142                 /* not allocated from unrhdr */
 143                 return;
 144         case pfstype_dir:
 145         case pfstype_file:
 146         case pfstype_symlink:
 147         case pfstype_procdir:
 148                 free_unr(pn->pn_info->pi_unrhdr, pn->pn_fileno);
 149                 break;
 150         case pfstype_this:
 151         case pfstype_parent:
 152                 /* ignore these, as they don't "own" their file number */
 153                 break;
 154         case pfstype_none:
 155                 KASSERT(0,
 156                     ("pfs_fileno_free() called for pfstype_none node"));
 157                 break;
 158         }
 159 }