vfs_init.c

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    1 /*
    2  * Copyright (c) 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * This code is derived from software contributed
    6  * to Berkeley by John Heidemann of the UCLA Ficus project.
    7  *
    8  * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 3. All advertising materials mentioning features or use of this software
   19  *    must display the following acknowledgement:
   20  *      This product includes software developed by the University of
   21  *      California, Berkeley and its contributors.
   22  * 4. Neither the name of the University nor the names of its contributors
   23  *    may be used to endorse or promote products derived from this software
   24  *    without specific prior written permission.
   25  *
   26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   36  * SUCH DAMAGE.
   37  *
   38  *      @(#)vfs_init.c  8.3 (Berkeley) 1/4/94
   39  * $FreeBSD$
   40  */
   41 
   42 
   43 #include <sys/param.h>
   44 #include <sys/systm.h>
   45 #include <sys/kernel.h>
   46 #include <sys/mount.h>
   47 #include <sys/sysctl.h>
   48 #include <sys/vnode.h>
   49 #include <sys/malloc.h>
   50 #include <vm/vm_zone.h>
   51 
   52 
   53 MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes");
   54 
   55 /*
   56  * XXX this bloat just exands the sysctl__vfs linker set a little so that
   57  * we can attach sysctls for VFS modules without expanding the linker set.
   58  * Currently (1998/09/06), only one VFS uses sysctls, so 2 extra linker
   59  * set slots are more than sufficient.
   60  */
   61 extern struct linker_set sysctl__vfs;
   62 static int mod_xx;
   63 SYSCTL_INT(_vfs, OID_AUTO, mod0, CTLFLAG_RD, &mod_xx, 0, "");
   64 SYSCTL_INT(_vfs, OID_AUTO, mod1, CTLFLAG_RD, &mod_xx, 0, "");
   65 
   66 /*
   67  * Zone for namei
   68  */
   69 struct vm_zone *namei_zone;
   70 
   71 /*
   72  * vfs_init.c
   73  *
   74  * Allocate and fill in operations vectors.
   75  *
   76  * An undocumented feature of this approach to defining operations is that
   77  * there can be multiple entries in vfs_opv_descs for the same operations
   78  * vector. This allows third parties to extend the set of operations
   79  * supported by another layer in a binary compatibile way. For example,
   80  * assume that NFS needed to be modified to support Ficus. NFS has an entry
   81  * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by
   82  * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions)
   83  * listing those new operations Ficus adds to NFS, all without modifying the
   84  * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but
   85  * that is a(whole)nother story.) This is a feature.
   86  */
   87 
   88 /* Table of known vnodeop vectors (list of VFS vnode vectors) */
   89 static struct vnodeopv_desc **vnodeopv_descs;
   90 static int vnodeopv_num;
   91 
   92 /* Table of known descs (list of vnode op handlers "vop_access_desc") */
   93 static struct vnodeop_desc **vfs_op_descs;
   94 static int *vfs_op_desc_refs;                   /* reference counts */
   95 static int num_op_descs;
   96 static int vfs_opv_numops;
   97 
   98 static void
   99 vfs_opv_recalc(void)
  100 {
  101         int i, j;
  102         vop_t ***opv_desc_vector_p;
  103         vop_t **opv_desc_vector;
  104         struct vnodeopv_entry_desc *opve_descp;
  105         struct vnodeopv_desc *opv;
  106 
  107         if (vfs_op_descs == NULL)
  108                 panic("vfs_opv_recalc called with null vfs_op_descs");
  109 
  110         /*
  111          * Run through and make sure all known descs have an offset
  112          *
  113          * vop_default_desc is hardwired at offset 1, and offset 0
  114          * is a panic sanity check.
  115          */
  116         vfs_opv_numops = 0;
  117         for (i = 0; i < num_op_descs; i++)
  118                 if (vfs_opv_numops < (vfs_op_descs[i]->vdesc_offset + 1))
  119                         vfs_opv_numops = vfs_op_descs[i]->vdesc_offset + 1;
  120         for (i = 0; i < num_op_descs; i++)
  121                 if (vfs_op_descs[i]->vdesc_offset == 0)
  122                         vfs_op_descs[i]->vdesc_offset = vfs_opv_numops++;
  123         /*
  124          * Allocate and fill in the vectors
  125          */
  126         for (i = 0; i < vnodeopv_num; i++) {
  127                 opv = vnodeopv_descs[i];
  128                 opv_desc_vector_p = opv->opv_desc_vector_p;
  129                 if (*opv_desc_vector_p)
  130                         FREE(*opv_desc_vector_p, M_VNODE);
  131                 MALLOC(*opv_desc_vector_p, vop_t **,
  132                        vfs_opv_numops * sizeof(vop_t *), M_VNODE, M_WAITOK);
  133                 if (*opv_desc_vector_p == NULL)
  134                         panic("no memory for vop_t ** vector");
  135                 bzero(*opv_desc_vector_p, vfs_opv_numops * sizeof(vop_t *));
  136 
  137                 /* Fill in, with slot 0 being panic */
  138                 opv_desc_vector = *opv_desc_vector_p;
  139                 opv_desc_vector[0] = (vop_t *)vop_panic;
  140                 for (j = 0; opv->opv_desc_ops[j].opve_op; j++) {
  141                         opve_descp = &(opv->opv_desc_ops[j]);
  142                         opv_desc_vector[opve_descp->opve_op->vdesc_offset] =
  143                                 opve_descp->opve_impl;
  144                 }
  145 
  146                 /* Replace unfilled routines with their default (slot 1). */
  147                 opv_desc_vector = *(opv->opv_desc_vector_p);
  148                 if (opv_desc_vector[1] == NULL)
  149                         panic("vfs_opv_recalc: vector without a default.");
  150                 for (j = 0; j < vfs_opv_numops; j++)
  151                         if (opv_desc_vector[j] == NULL)
  152                                 opv_desc_vector[j] = opv_desc_vector[1];
  153         }
  154 }
  155 
  156 void
  157 vfs_add_vnodeops(void *data)
  158 {
  159         struct vnodeopv_desc *opv;
  160         struct vnodeopv_desc **newopv;
  161         struct vnodeop_desc **newop;
  162         int *newref;
  163         vop_t **opv_desc_vector;
  164         struct vnodeop_desc *desc;
  165         int i, j;
  166 
  167         opv = (struct vnodeopv_desc *)data;
  168         MALLOC(newopv, struct vnodeopv_desc **,
  169                (vnodeopv_num + 1) * sizeof(*newopv), M_VNODE, M_WAITOK);
  170         if (newopv == NULL)
  171                 panic("vfs_add_vnodeops: no memory");
  172         if (vnodeopv_descs) {
  173                 bcopy(vnodeopv_descs, newopv, vnodeopv_num * sizeof(*newopv));
  174                 FREE(vnodeopv_descs, M_VNODE);
  175         }
  176         newopv[vnodeopv_num] = opv;
  177         vnodeopv_descs = newopv;
  178         vnodeopv_num++;
  179 
  180         /* See if we have turned up a new vnode op desc */
  181         opv_desc_vector = *(opv->opv_desc_vector_p);
  182         for (i = 0; (desc = opv->opv_desc_ops[i].opve_op); i++) {
  183                 for (j = 0; j < num_op_descs; j++) {
  184                         if (desc == vfs_op_descs[j]) {
  185                                 /* found it, increase reference count */
  186                                 vfs_op_desc_refs[j]++;
  187                                 break;
  188                         }
  189                 }
  190                 if (j == num_op_descs) {
  191                         /* not found, new entry */
  192                         MALLOC(newop, struct vnodeop_desc **,
  193                                (num_op_descs + 1) * sizeof(*newop),
  194                                M_VNODE, M_WAITOK);
  195                         if (newop == NULL)
  196                                 panic("vfs_add_vnodeops: no memory for desc");
  197                         /* new reference count (for unload) */
  198                         MALLOC(newref, int *,
  199                                 (num_op_descs + 1) * sizeof(*newref),
  200                                 M_VNODE, M_WAITOK);
  201                         if (newref == NULL)
  202                                 panic("vfs_add_vnodeops: no memory for refs");
  203                         if (vfs_op_descs) {
  204                                 bcopy(vfs_op_descs, newop,
  205                                         num_op_descs * sizeof(*newop));
  206                                 FREE(vfs_op_descs, M_VNODE);
  207                         }
  208                         if (vfs_op_desc_refs) {
  209                                 bcopy(vfs_op_desc_refs, newref,
  210                                         num_op_descs * sizeof(*newref));
  211                                 FREE(vfs_op_desc_refs, M_VNODE);
  212                         }
  213                         newop[num_op_descs] = desc;
  214                         newref[num_op_descs] = 1;
  215                         vfs_op_descs = newop;
  216                         vfs_op_desc_refs = newref;
  217                         num_op_descs++;
  218                 }
  219         }
  220         vfs_opv_recalc();
  221 }
  222 
  223 void
  224 vfs_rm_vnodeops(void *data)
  225 {
  226         struct vnodeopv_desc *opv;
  227         struct vnodeopv_desc **newopv;
  228         struct vnodeop_desc **newop;
  229         int *newref;
  230         vop_t **opv_desc_vector;
  231         struct vnodeop_desc *desc;
  232         int i, j, k;
  233 
  234         opv = (struct vnodeopv_desc *)data;
  235         /* Lower ref counts on descs in the table and release if zero */
  236         opv_desc_vector = *(opv->opv_desc_vector_p);
  237         for (i = 0; (desc = opv->opv_desc_ops[i].opve_op); i++) {
  238                 for (j = 0; j < num_op_descs; j++) {
  239                         if (desc == vfs_op_descs[j]) {
  240                                 /* found it, decrease reference count */
  241                                 vfs_op_desc_refs[j]--;
  242                                 break;
  243                         }
  244                 }
  245                 for (j = 0; j < num_op_descs; j++) {
  246                         if (vfs_op_desc_refs[j] > 0)
  247                                 continue;
  248                         if (vfs_op_desc_refs[j] < 0)
  249                                 panic("vfs_remove_vnodeops: negative refcnt");
  250                         MALLOC(newop, struct vnodeop_desc **,
  251                                (num_op_descs - 1) * sizeof(*newop),
  252                                M_VNODE, M_WAITOK);
  253                         if (newop == NULL)
  254                                 panic("vfs_remove_vnodeops: no memory for desc");
  255                         /* new reference count (for unload) */
  256                         MALLOC(newref, int *,
  257                                 (num_op_descs - 1) * sizeof(*newref),
  258                                 M_VNODE, M_WAITOK);
  259                         if (newref == NULL)
  260                                 panic("vfs_remove_vnodeops: no memory for refs");
  261                         for (k = j; k < (num_op_descs - 1); k++) {
  262                                 vfs_op_descs[k] = vfs_op_descs[k + 1];
  263                                 vfs_op_desc_refs[k] = vfs_op_desc_refs[k + 1];
  264                         }
  265                         bcopy(vfs_op_descs, newop,
  266                                 (num_op_descs - 1) * sizeof(*newop));
  267                         bcopy(vfs_op_desc_refs, newref,
  268                                 (num_op_descs - 1) * sizeof(*newref));
  269                         FREE(vfs_op_descs, M_VNODE);
  270                         FREE(vfs_op_desc_refs, M_VNODE);
  271                         vfs_op_descs = newop;
  272                         vfs_op_desc_refs = newref;
  273                         num_op_descs--;
  274                 }
  275         }
  276 
  277         for (i = 0; i < vnodeopv_num; i++) {
  278                 if (vnodeopv_descs[i] == opv) {
  279                         for (j = i; j < (vnodeopv_num - 1); j++)
  280                                 vnodeopv_descs[j] = vnodeopv_descs[j + 1];
  281                         break;
  282                 }
  283         }
  284         if (i == vnodeopv_num)
  285                 panic("vfs_remove_vnodeops: opv not found");
  286         MALLOC(newopv, struct vnodeopv_desc **,
  287                (vnodeopv_num - 1) * sizeof(*newopv), M_VNODE, M_WAITOK);
  288         if (newopv == NULL)
  289                 panic("vfs_remove_vnodeops: no memory");
  290         bcopy(vnodeopv_descs, newopv, (vnodeopv_num - 1) * sizeof(*newopv));
  291         FREE(vnodeopv_descs, M_VNODE);
  292         vnodeopv_descs = newopv;
  293         vnodeopv_num--;
  294 
  295         vfs_opv_recalc();
  296 }
  297 
  298 /*
  299  * Routines having to do with the management of the vnode table.
  300  */
  301 struct vattr va_null;
  302 
  303 /*
  304  * Initialize the vnode structures and initialize each file system type.
  305  */
  306 /* ARGSUSED*/
  307 static void
  308 vfsinit(void *dummy)
  309 {
  310 
  311         namei_zone = zinit("NAMEI", MAXPATHLEN, 0, 0, 2);
  312 
  313         /*
  314          * Initialize the vnode table
  315          */
  316         vntblinit();
  317         /*
  318          * Initialize the vnode name cache
  319          */
  320         nchinit();
  321         /*
  322          * Initialize each file system type.
  323          * Vfs type numbers must be distinct from VFS_GENERIC (and VFS_VFSCONF).
  324          */
  325         vattr_null(&va_null);
  326         maxvfsconf = VFS_GENERIC + 1;
  327 }
  328 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vfsinit, NULL)
  329 
  330 int
  331 vfs_register(struct vfsconf *vfc)
  332 {
  333         struct linker_set *l;
  334         struct sysctl_oid **oidpp;
  335         struct vfsconf *vfsp;
  336         int i, exists;
  337 
  338         vfsp = NULL;
  339         l = &sysctl__vfs;
  340         if (vfsconf)
  341                 for (vfsp = vfsconf; vfsp->vfc_next; vfsp = vfsp->vfc_next)
  342                         if (!strcmp(vfc->vfc_name, vfsp->vfc_name))
  343                                 return EEXIST;
  344 
  345         vfc->vfc_typenum = maxvfsconf++;
  346         if (vfc->vfc_vfsops->vfs_oid != NULL) {
  347                 /*
  348                  * Attach the oid to the "vfs" node of the sysctl tree if
  349                  * it isn't already there (it will be there for statically
  350                  * configured vfs's).
  351                  */
  352                 exists = 0;
  353                 for (i = l->ls_length,
  354                     oidpp = (struct sysctl_oid **)l->ls_items;
  355                     i-- != 0; oidpp++)
  356                         if (*oidpp == vfc->vfc_vfsops->vfs_oid) {
  357                                 exists = 1;
  358                                 break;
  359                         }
  360                 if (exists == 0)
  361                         for (i = l->ls_length,
  362                             oidpp = (struct sysctl_oid **)l->ls_items;
  363                             i-- != 0; oidpp++) {
  364                                 if (*oidpp == NULL ||
  365                                     *oidpp == &sysctl___vfs_mod0 ||
  366                                     *oidpp == &sysctl___vfs_mod1) {
  367                                         *oidpp = vfc->vfc_vfsops->vfs_oid;
  368                                         break;
  369                                 }
  370                         }
  371 
  372                 vfc->vfc_vfsops->vfs_oid->oid_number = vfc->vfc_typenum;
  373                 sysctl_order_all();
  374         }
  375         if (vfsp)
  376                 vfsp->vfc_next = vfc;
  377         else
  378                 vfsconf = vfc;
  379         vfc->vfc_next = NULL;
  380 
  381         /*
  382          * Call init function for this VFS...
  383          */
  384         (*(vfc->vfc_vfsops->vfs_init))(vfc);
  385 
  386         return 0;
  387 }
  388 
  389 
  390 int
  391 vfs_unregister(struct vfsconf *vfc)
  392 {
  393         struct linker_set *l;
  394         struct sysctl_oid **oidpp;
  395         struct vfsconf *vfsp, *prev_vfsp;
  396         int error, i, maxtypenum;
  397 
  398         i = vfc->vfc_typenum;
  399 
  400         prev_vfsp = NULL;
  401         for (vfsp = vfsconf; vfsp;
  402                         prev_vfsp = vfsp, vfsp = vfsp->vfc_next) {
  403                 if (!strcmp(vfc->vfc_name, vfsp->vfc_name))
  404                         break;
  405         }
  406         if (vfsp == NULL)
  407                 return EINVAL;
  408         if (vfsp->vfc_refcount)
  409                 return EBUSY;
  410         if (vfc->vfc_vfsops->vfs_uninit != NULL) {
  411                 error = (*vfc->vfc_vfsops->vfs_uninit)(vfsp);
  412                 if (error)
  413                         return (error);
  414         }
  415         if (prev_vfsp)
  416                 prev_vfsp->vfc_next = vfsp->vfc_next;
  417         else
  418                 vfsconf = vfsp->vfc_next;
  419         if (vfsp->vfc_vfsops->vfs_oid != NULL) {
  420                 l = &sysctl__vfs;
  421                 for (i = l->ls_length,
  422                     oidpp = (struct sysctl_oid **)l->ls_items;
  423                     i--; oidpp++) {
  424                         if (*oidpp == vfsp->vfc_vfsops->vfs_oid) {
  425                                 *oidpp = NULL;
  426                                 sysctl_order_all();
  427                                 break;
  428                         }
  429                 }
  430         }
  431         maxtypenum = VFS_GENERIC;
  432         for (vfsp = vfsconf; vfsp != NULL; vfsp = vfsp->vfc_next)
  433                 if (maxtypenum < vfsp->vfc_typenum)
  434                         maxtypenum = vfsp->vfc_typenum;
  435         maxvfsconf = maxtypenum + 1;
  436         return 0;
  437 }
  438 
  439 int
  440 vfs_modevent(module_t mod, int type, void *data)
  441 {
  442         struct vfsconf *vfc;
  443         int error = 0;
  444 
  445         vfc = (struct vfsconf *)data;
  446 
  447         switch (type) {
  448         case MOD_LOAD:
  449                 if (vfc)
  450                         error = vfs_register(vfc);
  451                 break;
  452 
  453         case MOD_UNLOAD:
  454                 if (vfc)
  455                         error = vfs_unregister(vfc);
  456                 break;
  457         default:        /* including MOD_SHUTDOWN */
  458                 break;
  459         }
  460         return (error);
  461 }
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FreeBSD/Linux Kernel Cross Reference sys/kern/vfs_init.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_init.c
