pseudofs_fileno.c revision 143592
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 29143592Sdes#include <sys/cdefs.h> 30143592Sdes__FBSDID("$FreeBSD: head/sys/fs/pseudofs/pseudofs_fileno.c 143592 2005-03-14 15:54:11Z des $"); 31143592Sdes 32143592Sdes#include "opt_pseudofs.h" 33143592Sdes 3475295Sdes#include <sys/param.h> 3575295Sdes#include <sys/kernel.h> 3675295Sdes#include <sys/systm.h> 37114216Skan#include <sys/limits.h> 3878073Sdes#include <sys/lock.h> 3975295Sdes#include <sys/malloc.h> 4077965Sdes#include <sys/mutex.h> 4175295Sdes#include <sys/sysctl.h> 4275295Sdes 4375295Sdes#include <fs/pseudofs/pseudofs.h> 4475295Sdes#include <fs/pseudofs/pseudofs_internal.h> 4575295Sdes 4677998Sdesstatic MALLOC_DEFINE(M_PFSFILENO, "pfs_fileno", "pseudofs fileno bitmap"); 4775295Sdes 4875295Sdesstatic struct mtx pfs_fileno_mutex; 4975295Sdes 5075295Sdes#define PFS_BITMAP_SIZE 4096 5177998Sdes#define PFS_SLOT_BITS (int)(sizeof(unsigned int) * CHAR_BIT) 5275295Sdes#define PFS_BITMAP_BITS (PFS_BITMAP_SIZE * PFS_SLOT_BITS) 5375295Sdesstruct pfs_bitmap { 5475295Sdes u_int32_t pb_offset; 5575295Sdes int pb_used; 5675295Sdes unsigned int pb_bitmap[PFS_BITMAP_SIZE]; 5775295Sdes struct pfs_bitmap *pb_next; 5875295Sdes}; 5975295Sdes 6075295Sdes/* 6175295Sdes * Initialization 6275295Sdes */ 6375295Sdesvoid 6475295Sdespfs_fileno_load(void) 6575295Sdes{ 6693818Sjhb mtx_init(&pfs_fileno_mutex, "pseudofs_fileno", NULL, MTX_DEF); 6775295Sdes} 6875295Sdes 6975295Sdes/* 7075295Sdes * Teardown 7175295Sdes */ 7275295Sdesvoid 7375295Sdespfs_fileno_unload(void) 7475295Sdes{ 7575295Sdes mtx_destroy(&pfs_fileno_mutex); 7675295Sdes} 7775295Sdes 7875295Sdes/* 7975295Sdes * Initialize fileno bitmap 8075295Sdes */ 8175295Sdesvoid 8275295Sdespfs_fileno_init(struct pfs_info *pi) 8375295Sdes{ 8475295Sdes struct pfs_bitmap *pb; 8597940Sdes 8675295Sdes MALLOC(pb, struct pfs_bitmap *, sizeof *pb, 87111119Simp M_PFSFILENO, M_WAITOK|M_ZERO); 8875295Sdes 8975295Sdes mtx_lock(&pi->pi_mutex); 9097940Sdes 9175295Sdes pb->pb_bitmap[0] = 07; 9275295Sdes pb->pb_used = 3; 9375295Sdes pi->pi_bitmap = pb; 9475295Sdes pi->pi_root->pn_fileno = 2; 9575295Sdes 9675295Sdes mtx_unlock(&pi->pi_mutex); 9775295Sdes} 9875295Sdes 9975295Sdes/* 10075295Sdes * Tear down fileno bitmap 10175295Sdes */ 10275295Sdesvoid 10375295Sdespfs_fileno_uninit(struct pfs_info *pi) 10475295Sdes{ 10575295Sdes struct pfs_bitmap *pb, *npb; 10675295Sdes int used; 10797940Sdes 10875295Sdes mtx_lock(&pi->pi_mutex); 10997940Sdes 11075295Sdes pb = pi->pi_bitmap; 11175295Sdes pi->pi_bitmap = NULL; 11297940Sdes 11375295Sdes mtx_unlock(&pi->pi_mutex); 11475295Sdes 11575295Sdes for (used = 0; pb; pb = npb) { 11675295Sdes npb = pb->pb_next; 11775295Sdes used += pb->pb_used; 11875295Sdes FREE(pb, M_PFSFILENO); 11975295Sdes } 12077998Sdes#if 0 12177998Sdes /* we currently don't reclaim filenos */ 12275295Sdes if (used > 2) 12375295Sdes printf("WARNING: %d file numbers still in use\n", used); 12477998Sdes#endif 12575295Sdes} 12675295Sdes 12775295Sdes/* 12875295Sdes * Get the next available file number 12975295Sdes */ 13075295Sdesstatic u_int32_t 13175295Sdespfs_get_fileno(struct pfs_info *pi) 13275295Sdes{ 13375295Sdes struct pfs_bitmap *pb, *ppb; 13475295Sdes u_int32_t fileno; 13575295Sdes unsigned int *p; 13675295Sdes int i; 13775295Sdes 13875295Sdes mtx_lock(&pi->pi_mutex); 13997940Sdes 14075295Sdes /* look for the first page with free bits */ 14175295Sdes for (ppb = NULL, pb = pi->pi_bitmap; pb; ppb = pb, pb = pb->pb_next) 14275295Sdes if (pb->pb_used != PFS_BITMAP_BITS) 14375295Sdes break; 14475295Sdes 14575295Sdes /* out of pages? */ 14675295Sdes if (pb == NULL) { 14775295Sdes mtx_unlock(&pi->pi_mutex); 14875295Sdes MALLOC(pb, struct pfs_bitmap *, sizeof *pb, 149111119Simp M_PFSFILENO, M_WAITOK|M_ZERO); 15075295Sdes mtx_lock(&pi->pi_mutex); 15175295Sdes /* protect against possible race */ 15275295Sdes while (ppb->pb_next) 15375295Sdes ppb = ppb->pb_next; 15475295Sdes pb->pb_offset = ppb->pb_offset + PFS_BITMAP_BITS; 15575295Sdes ppb->pb_next = pb; 15675295Sdes } 15775295Sdes 15875295Sdes /* find the first free slot */ 15975295Sdes for (i = 0; i < PFS_BITMAP_SIZE; ++i) 16075295Sdes if (pb->pb_bitmap[i] != UINT_MAX) 16175295Sdes break; 16297940Sdes 16375295Sdes /* find the first available bit and flip it */ 16475295Sdes fileno = pb->pb_offset + i * PFS_SLOT_BITS; 16575295Sdes p = &pb->pb_bitmap[i]; 16675295Sdes for (i = 0; i < PFS_SLOT_BITS; ++i, ++fileno) 16775295Sdes if ((*p & (unsigned int)(1 << i)) == 0) 16875295Sdes break; 16975295Sdes KASSERT(i < PFS_SLOT_BITS, 17075295Sdes ("slot has free bits, yet doesn't")); 17175295Sdes *p |= (unsigned int)(1 << i); 17275295Sdes ++pb->pb_used; 17397940Sdes 17475295Sdes mtx_unlock(&pi->pi_mutex); 17597940Sdes 17675295Sdes return fileno; 17775295Sdes} 17875295Sdes 17975295Sdes/* 18075295Sdes * Free a file number 18175295Sdes */ 18275295Sdesstatic void 18375295Sdespfs_free_fileno(struct pfs_info *pi, u_int32_t fileno) 18475295Sdes{ 18575295Sdes struct pfs_bitmap *pb; 18675295Sdes unsigned int *p; 18775295Sdes int i; 18875295Sdes 18975295Sdes mtx_lock(&pi->pi_mutex); 19097940Sdes 19175295Sdes /* find the right page */ 19275295Sdes for (pb = pi->pi_bitmap; 19375295Sdes pb && fileno >= PFS_BITMAP_BITS; 19475295Sdes pb = pb->pb_next, fileno -= PFS_BITMAP_BITS) 19575295Sdes /* nothing */ ; 19675295Sdes KASSERT(pb, 19775295Sdes ("fileno isn't in any bitmap")); 19875295Sdes 19975295Sdes /* find the right bit in the right slot and flip it */ 20075295Sdes p = &pb->pb_bitmap[fileno / PFS_SLOT_BITS]; 20175295Sdes i = fileno % PFS_SLOT_BITS; 20275295Sdes KASSERT(*p & (unsigned int)(1 << i), 20375295Sdes ("fileno is already free")); 20475295Sdes *p &= ~((unsigned int)(1 << i)); 20575295Sdes --pb->pb_used; 20675295Sdes 20775295Sdes mtx_unlock(&pi->pi_mutex); 20877998Sdes printf("pfs_free_fileno(): reclaimed %d\n", fileno); 20975295Sdes} 21075295Sdes 21175295Sdes/* 21275295Sdes * Allocate a file number 21375295Sdes */ 21475295Sdesvoid 21575295Sdespfs_fileno_alloc(struct pfs_info *pi, struct pfs_node *pn) 21675295Sdes{ 21775295Sdes /* make sure our parent has a file number */ 21875295Sdes if (pn->pn_parent && !pn->pn_parent->pn_fileno) 21975295Sdes pfs_fileno_alloc(pi, pn->pn_parent); 22097940Sdes 22175295Sdes switch (pn->pn_type) { 22275295Sdes case pfstype_root: 22375295Sdes case pfstype_dir: 22475295Sdes case pfstype_file: 22575295Sdes case pfstype_symlink: 22677998Sdes case pfstype_procdir: 22775295Sdes pn->pn_fileno = pfs_get_fileno(pi); 22875295Sdes break; 22975295Sdes case pfstype_this: 23075295Sdes KASSERT(pn->pn_parent != NULL, 23175295Sdes ("pfstype_this node has no parent")); 23275295Sdes pn->pn_fileno = pn->pn_parent->pn_fileno; 23375295Sdes break; 23475295Sdes case pfstype_parent: 23575295Sdes KASSERT(pn->pn_parent != NULL, 23675295Sdes ("pfstype_parent node has no parent")); 23775295Sdes if (pn->pn_parent == pi->pi_root) { 23875295Sdes pn->pn_fileno = pn->pn_parent->pn_fileno; 23975295Sdes break; 24075295Sdes } 24175295Sdes KASSERT(pn->pn_parent->pn_parent != NULL, 24275295Sdes ("pfstype_parent node has no grandparent")); 24375295Sdes pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno; 24475295Sdes break; 24575295Sdes case pfstype_none: 24677998Sdes KASSERT(0, 24775295Sdes ("pfs_fileno_alloc() called for pfstype_none node")); 24875295Sdes break; 24997940Sdes } 25077998Sdes 25177998Sdes#if 0 25275295Sdes printf("pfs_fileno_alloc(): %s: ", pi->pi_name); 25375295Sdes if (pn->pn_parent) { 25475295Sdes if (pn->pn_parent->pn_parent) { 25575295Sdes printf("%s/", pn->pn_parent->pn_parent->pn_name); 25675295Sdes } 25775295Sdes printf("%s/", pn->pn_parent->pn_name); 25875295Sdes } 25975295Sdes printf("%s -> %d\n", pn->pn_name, pn->pn_fileno); 26077998Sdes#endif 26175295Sdes} 26275295Sdes 26375295Sdes/* 26475295Sdes * Release a file number 26575295Sdes */ 26675295Sdesvoid 26775295Sdespfs_fileno_free(struct pfs_info *pi, struct pfs_node *pn) 26875295Sdes{ 26975295Sdes switch (pn->pn_type) { 27075295Sdes case pfstype_root: 27175295Sdes case pfstype_dir: 27275295Sdes case pfstype_file: 27375295Sdes case pfstype_symlink: 27477998Sdes case pfstype_procdir: 27575295Sdes pfs_free_fileno(pi, pn->pn_fileno); 27675295Sdes break; 27775295Sdes case pfstype_this: 27875295Sdes case pfstype_parent: 27975295Sdes /* ignore these, as they don't "own" their file number */ 28075295Sdes break; 28175295Sdes case pfstype_none: 28277998Sdes KASSERT(0, 28375295Sdes ("pfs_fileno_free() called for pfstype_none node")); 28475295Sdes break; 28575295Sdes } 28675295Sdes} 287