pseudofs_fileno.c revision 75295
175295Sdes/*- 275295Sdes * Copyright (c) 2001 Dag-Erling Co�dan Sm�rgrav 375295Sdes * All rights reserved. 475295Sdes * 575295Sdes * Redistribution and use in source and binary forms, with or without 675295Sdes * modification, are permitted provided that the following conditions 775295Sdes * are met: 875295Sdes * 1. Redistributions of source code must retain the above copyright 975295Sdes * notice, this list of conditions and the following disclaimer 1075295Sdes * in this position and unchanged. 1175295Sdes * 2. Redistributions in binary form must reproduce the above copyright 1275295Sdes * notice, this list of conditions and the following disclaimer in the 1375295Sdes * documentation and/or other materials provided with the distribution. 1475295Sdes * 3. The name of the author may not be used to endorse or promote products 1575295Sdes * derived from this software without specific prior written permission. 1675295Sdes * 1775295Sdes * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1875295Sdes * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1975295Sdes * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 2075295Sdes * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 2175295Sdes * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 2275295Sdes * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 2375295Sdes * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2475295Sdes * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2575295Sdes * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2675295Sdes * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2775295Sdes * 2875295Sdes * $FreeBSD: head/sys/fs/pseudofs/pseudofs_fileno.c 75295 2001-04-07 19:51:12Z des $ 2975295Sdes */ 3075295Sdes 3175295Sdes#include <sys/param.h> 3275295Sdes#include <sys/kernel.h> 3375295Sdes#include <sys/systm.h> 3475295Sdes#include <sys/malloc.h> 3575295Sdes#include <sys/mount.h> 3675295Sdes#include <sys/proc.h> 3775295Sdes#include <sys/sbuf.h> 3875295Sdes#include <sys/sysctl.h> 3975295Sdes 4075295Sdes#include <machine/limits.h> 4175295Sdes 4275295Sdes#include <fs/pseudofs/pseudofs.h> 4375295Sdes#include <fs/pseudofs/pseudofs_internal.h> 4475295Sdes 4575295Sdesstatic MALLOC_DEFINE(M_PFSFILENO, "pseudofs_fileno", "pseudofs fileno bitmap"); 4675295Sdes 4775295Sdesstatic struct mtx pfs_fileno_mutex; 4875295Sdes 4975295Sdes#define PFS_BITMAP_SIZE 4096 5075295Sdes#define PFS_SLOT_BITS (sizeof(unsigned int) * CHAR_BIT) 5175295Sdes#define PFS_BITMAP_BITS (PFS_BITMAP_SIZE * PFS_SLOT_BITS) 5275295Sdesstruct pfs_bitmap { 5375295Sdes u_int32_t pb_offset; 5475295Sdes int pb_used; 5575295Sdes unsigned int pb_bitmap[PFS_BITMAP_SIZE]; 5675295Sdes struct pfs_bitmap *pb_next; 5775295Sdes}; 5875295Sdes 5975295Sdes/* 6075295Sdes * Initialization 6175295Sdes */ 6275295Sdesvoid 6375295Sdespfs_fileno_load(void) 6475295Sdes{ 6575295Sdes mtx_init(&pfs_fileno_mutex, "pseudofs_fileno", MTX_DEF); 6675295Sdes} 6775295Sdes 6875295Sdes/* 6975295Sdes * Teardown 7075295Sdes */ 7175295Sdesvoid 7275295Sdespfs_fileno_unload(void) 7375295Sdes{ 7475295Sdes mtx_destroy(&pfs_fileno_mutex); 7575295Sdes} 7675295Sdes 7775295Sdes/* 7875295Sdes * Initialize fileno bitmap 7975295Sdes */ 8075295Sdesvoid 8175295Sdespfs_fileno_init(struct pfs_info *pi) 8275295Sdes{ 8375295Sdes struct pfs_bitmap *pb; 8475295Sdes 8575295Sdes MALLOC(pb, struct pfs_bitmap *, sizeof *pb, 8675295Sdes M_PFSFILENO, M_WAITOK|M_ZERO); 8775295Sdes 8875295Sdes mtx_lock(&pi->pi_mutex); 8975295Sdes 9075295Sdes pb->pb_bitmap[0] = 07; 9175295Sdes pb->pb_used = 3; 9275295Sdes pi->pi_bitmap = pb; 9375295Sdes pi->pi_root->pn_fileno = 2; 9475295Sdes 9575295Sdes mtx_unlock(&pi->pi_mutex); 9675295Sdes} 9775295Sdes 9875295Sdes/* 9975295Sdes * Tear down fileno bitmap 10075295Sdes */ 10175295Sdesvoid 10275295Sdespfs_fileno_uninit(struct pfs_info *pi) 10375295Sdes{ 10475295Sdes struct pfs_bitmap *pb, *npb; 10575295Sdes int used; 10675295Sdes 10775295Sdes mtx_lock(&pi->pi_mutex); 10875295Sdes 10975295Sdes pb = pi->pi_bitmap; 11075295Sdes pi->pi_bitmap = NULL; 11175295Sdes 11275295Sdes mtx_unlock(&pi->pi_mutex); 11375295Sdes 11475295Sdes for (used = 0; pb; pb = npb) { 11575295Sdes npb = pb->pb_next; 11675295Sdes used += pb->pb_used; 11775295Sdes FREE(pb, M_PFSFILENO); 11875295Sdes } 11975295Sdes if (used > 2) 12075295Sdes printf("WARNING: %d file numbers still in use\n", used); 12175295Sdes} 12275295Sdes 12375295Sdes/* 12475295Sdes * Get the next available file number 12575295Sdes */ 12675295Sdesstatic u_int32_t 12775295Sdespfs_get_fileno(struct pfs_info *pi) 12875295Sdes{ 12975295Sdes struct pfs_bitmap *pb, *ppb; 13075295Sdes u_int32_t fileno; 13175295Sdes unsigned int *p; 13275295Sdes int i; 13375295Sdes 13475295Sdes mtx_lock(&pi->pi_mutex); 13575295Sdes 13675295Sdes /* look for the first page with free bits */ 13775295Sdes for (ppb = NULL, pb = pi->pi_bitmap; pb; ppb = pb, pb = pb->pb_next) 13875295Sdes if (pb->pb_used != PFS_BITMAP_BITS) 13975295Sdes break; 14075295Sdes 14175295Sdes /* out of pages? */ 14275295Sdes if (pb == NULL) { 14375295Sdes mtx_unlock(&pi->pi_mutex); 14475295Sdes MALLOC(pb, struct pfs_bitmap *, sizeof *pb, 14575295Sdes M_PFSFILENO, M_WAITOK|M_ZERO); 14675295Sdes mtx_lock(&pi->pi_mutex); 14775295Sdes /* protect against possible race */ 14875295Sdes while (ppb->pb_next) 14975295Sdes ppb = ppb->pb_next; 15075295Sdes pb->pb_offset = ppb->pb_offset + PFS_BITMAP_BITS; 15175295Sdes ppb->pb_next = pb; 15275295Sdes } 15375295Sdes 15475295Sdes /* find the first free slot */ 15575295Sdes for (i = 0; i < PFS_BITMAP_SIZE; ++i) 15675295Sdes if (pb->pb_bitmap[i] != UINT_MAX) 15775295Sdes break; 15875295Sdes 15975295Sdes /* find the first available bit and flip it */ 16075295Sdes fileno = pb->pb_offset + i * PFS_SLOT_BITS; 16175295Sdes p = &pb->pb_bitmap[i]; 16275295Sdes for (i = 0; i < PFS_SLOT_BITS; ++i, ++fileno) 16375295Sdes if ((*p & (unsigned int)(1 << i)) == 0) 16475295Sdes break; 16575295Sdes KASSERT(i < PFS_SLOT_BITS, 16675295Sdes ("slot has free bits, yet doesn't")); 16775295Sdes *p |= (unsigned int)(1 << i); 16875295Sdes ++pb->pb_used; 16975295Sdes 17075295Sdes mtx_unlock(&pi->pi_mutex); 17175295Sdes 17275295Sdes return fileno; 17375295Sdes} 17475295Sdes 17575295Sdes/* 17675295Sdes * Free a file number 17775295Sdes */ 17875295Sdesstatic void 17975295Sdespfs_free_fileno(struct pfs_info *pi, u_int32_t fileno) 18075295Sdes{ 18175295Sdes struct pfs_bitmap *pb; 18275295Sdes unsigned int *p; 18375295Sdes int i; 18475295Sdes 18575295Sdes mtx_lock(&pi->pi_mutex); 18675295Sdes 18775295Sdes /* find the right page */ 18875295Sdes for (pb = pi->pi_bitmap; 18975295Sdes pb && fileno >= PFS_BITMAP_BITS; 19075295Sdes pb = pb->pb_next, fileno -= PFS_BITMAP_BITS) 19175295Sdes /* nothing */ ; 19275295Sdes KASSERT(pb, 19375295Sdes ("fileno isn't in any bitmap")); 19475295Sdes 19575295Sdes /* find the right bit in the right slot and flip it */ 19675295Sdes p = &pb->pb_bitmap[fileno / PFS_SLOT_BITS]; 19775295Sdes i = fileno % PFS_SLOT_BITS; 19875295Sdes KASSERT(*p & (unsigned int)(1 << i), 19975295Sdes ("fileno is already free")); 20075295Sdes *p &= ~((unsigned int)(1 << i)); 20175295Sdes --pb->pb_used; 20275295Sdes 20375295Sdes mtx_unlock(&pi->pi_mutex); 20475295Sdes} 20575295Sdes 20675295Sdes/* 20775295Sdes * Allocate a file number 20875295Sdes */ 20975295Sdesvoid 21075295Sdespfs_fileno_alloc(struct pfs_info *pi, struct pfs_node *pn) 21175295Sdes{ 21275295Sdes /* make sure our parent has a file number */ 21375295Sdes if (pn->pn_parent && !pn->pn_parent->pn_fileno) 21475295Sdes pfs_fileno_alloc(pi, pn->pn_parent); 21575295Sdes 21675295Sdes switch (pn->pn_type) { 21775295Sdes case pfstype_root: 21875295Sdes case pfstype_dir: 21975295Sdes case pfstype_file: 22075295Sdes case pfstype_symlink: 22175295Sdes pn->pn_fileno = pfs_get_fileno(pi); 22275295Sdes break; 22375295Sdes case pfstype_this: 22475295Sdes KASSERT(pn->pn_parent != NULL, 22575295Sdes ("pfstype_this node has no parent")); 22675295Sdes pn->pn_fileno = pn->pn_parent->pn_fileno; 22775295Sdes break; 22875295Sdes case pfstype_parent: 22975295Sdes KASSERT(pn->pn_parent != NULL, 23075295Sdes ("pfstype_parent node has no parent")); 23175295Sdes if (pn->pn_parent == pi->pi_root) { 23275295Sdes pn->pn_fileno = pn->pn_parent->pn_fileno; 23375295Sdes break; 23475295Sdes } 23575295Sdes KASSERT(pn->pn_parent->pn_parent != NULL, 23675295Sdes ("pfstype_parent node has no grandparent")); 23775295Sdes pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno; 23875295Sdes break; 23975295Sdes case pfstype_procdep: 24075295Sdes KASSERT(1, 24175295Sdes ("pfs_fileno_alloc() called for pfstype_procdep node")); 24275295Sdes break; 24375295Sdes case pfstype_none: 24475295Sdes KASSERT(1, 24575295Sdes ("pfs_fileno_alloc() called for pfstype_none node")); 24675295Sdes break; 24775295Sdes } 24875295Sdes 24975295Sdes printf("pfs_fileno_alloc(): %s: ", pi->pi_name); 25075295Sdes if (pn->pn_parent) { 25175295Sdes if (pn->pn_parent->pn_parent) { 25275295Sdes printf("%s/", pn->pn_parent->pn_parent->pn_name); 25375295Sdes } 25475295Sdes printf("%s/", pn->pn_parent->pn_name); 25575295Sdes } 25675295Sdes printf("%s -> %d\n", pn->pn_name, pn->pn_fileno); 25775295Sdes} 25875295Sdes 25975295Sdes/* 26075295Sdes * Release a file number 26175295Sdes */ 26275295Sdesvoid 26375295Sdespfs_fileno_free(struct pfs_info *pi, struct pfs_node *pn) 26475295Sdes{ 26575295Sdes switch (pn->pn_type) { 26675295Sdes case pfstype_root: 26775295Sdes case pfstype_dir: 26875295Sdes case pfstype_file: 26975295Sdes case pfstype_symlink: 27075295Sdes pfs_free_fileno(pi, pn->pn_fileno); 27175295Sdes break; 27275295Sdes case pfstype_this: 27375295Sdes case pfstype_parent: 27475295Sdes /* ignore these, as they don't "own" their file number */ 27575295Sdes break; 27675295Sdes case pfstype_procdep: 27775295Sdes KASSERT(1, 27875295Sdes ("pfs_fileno_free() called for pfstype_procdep node")); 27975295Sdes break; 28075295Sdes case pfstype_none: 28175295Sdes KASSERT(1, 28275295Sdes ("pfs_fileno_free() called for pfstype_none node")); 28375295Sdes break; 28475295Sdes } 28575295Sdes} 286