pseudofs_fileno.c revision 114216
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 114216 2003-04-29 13:36:06Z kan $ 2975295Sdes */ 3075295Sdes 3175295Sdes#include <sys/param.h> 3275295Sdes#include <sys/kernel.h> 3375295Sdes#include <sys/systm.h> 34114216Skan#include <sys/limits.h> 3578073Sdes#include <sys/lock.h> 3675295Sdes#include <sys/malloc.h> 3777965Sdes#include <sys/mutex.h> 3875295Sdes#include <sys/sysctl.h> 3975295Sdes 4075295Sdes#include <fs/pseudofs/pseudofs.h> 4175295Sdes#include <fs/pseudofs/pseudofs_internal.h> 4275295Sdes 4377998Sdesstatic MALLOC_DEFINE(M_PFSFILENO, "pfs_fileno", "pseudofs fileno bitmap"); 4475295Sdes 4575295Sdesstatic struct mtx pfs_fileno_mutex; 4675295Sdes 4775295Sdes#define PFS_BITMAP_SIZE 4096 4877998Sdes#define PFS_SLOT_BITS (int)(sizeof(unsigned int) * CHAR_BIT) 4975295Sdes#define PFS_BITMAP_BITS (PFS_BITMAP_SIZE * PFS_SLOT_BITS) 5075295Sdesstruct pfs_bitmap { 5175295Sdes u_int32_t pb_offset; 5275295Sdes int pb_used; 5375295Sdes unsigned int pb_bitmap[PFS_BITMAP_SIZE]; 5475295Sdes struct pfs_bitmap *pb_next; 5575295Sdes}; 5675295Sdes 5775295Sdes/* 5875295Sdes * Initialization 5975295Sdes */ 6075295Sdesvoid 6175295Sdespfs_fileno_load(void) 6275295Sdes{ 6393818Sjhb mtx_init(&pfs_fileno_mutex, "pseudofs_fileno", NULL, MTX_DEF); 6475295Sdes} 6575295Sdes 6675295Sdes/* 6775295Sdes * Teardown 6875295Sdes */ 6975295Sdesvoid 7075295Sdespfs_fileno_unload(void) 7175295Sdes{ 7275295Sdes mtx_destroy(&pfs_fileno_mutex); 7375295Sdes} 7475295Sdes 7575295Sdes/* 7675295Sdes * Initialize fileno bitmap 7775295Sdes */ 7875295Sdesvoid 7975295Sdespfs_fileno_init(struct pfs_info *pi) 8075295Sdes{ 8175295Sdes struct pfs_bitmap *pb; 8297940Sdes 8375295Sdes MALLOC(pb, struct pfs_bitmap *, sizeof *pb, 84111119Simp M_PFSFILENO, M_WAITOK|M_ZERO); 8575295Sdes 8675295Sdes mtx_lock(&pi->pi_mutex); 8797940Sdes 8875295Sdes pb->pb_bitmap[0] = 07; 8975295Sdes pb->pb_used = 3; 9075295Sdes pi->pi_bitmap = pb; 9175295Sdes pi->pi_root->pn_fileno = 2; 9275295Sdes 9375295Sdes mtx_unlock(&pi->pi_mutex); 9475295Sdes} 9575295Sdes 9675295Sdes/* 9775295Sdes * Tear down fileno bitmap 9875295Sdes */ 9975295Sdesvoid 10075295Sdespfs_fileno_uninit(struct pfs_info *pi) 10175295Sdes{ 10275295Sdes struct pfs_bitmap *pb, *npb; 10375295Sdes int used; 10497940Sdes 10575295Sdes mtx_lock(&pi->pi_mutex); 10697940Sdes 10775295Sdes pb = pi->pi_bitmap; 10875295Sdes pi->pi_bitmap = NULL; 10997940Sdes 11075295Sdes mtx_unlock(&pi->pi_mutex); 11175295Sdes 11275295Sdes for (used = 0; pb; pb = npb) { 11375295Sdes npb = pb->pb_next; 11475295Sdes used += pb->pb_used; 11575295Sdes FREE(pb, M_PFSFILENO); 11675295Sdes } 11777998Sdes#if 0 11877998Sdes /* we currently don't reclaim filenos */ 11975295Sdes if (used > 2) 12075295Sdes printf("WARNING: %d file numbers still in use\n", used); 12177998Sdes#endif 12275295Sdes} 12375295Sdes 12475295Sdes/* 12575295Sdes * Get the next available file number 12675295Sdes */ 12775295Sdesstatic u_int32_t 12875295Sdespfs_get_fileno(struct pfs_info *pi) 12975295Sdes{ 13075295Sdes struct pfs_bitmap *pb, *ppb; 13175295Sdes u_int32_t fileno; 13275295Sdes unsigned int *p; 13375295Sdes int i; 13475295Sdes 13575295Sdes mtx_lock(&pi->pi_mutex); 13697940Sdes 13775295Sdes /* look for the first page with free bits */ 13875295Sdes for (ppb = NULL, pb = pi->pi_bitmap; pb; ppb = pb, pb = pb->pb_next) 13975295Sdes if (pb->pb_used != PFS_BITMAP_BITS) 14075295Sdes break; 14175295Sdes 14275295Sdes /* out of pages? */ 14375295Sdes if (pb == NULL) { 14475295Sdes mtx_unlock(&pi->pi_mutex); 14575295Sdes MALLOC(pb, struct pfs_bitmap *, sizeof *pb, 146111119Simp M_PFSFILENO, M_WAITOK|M_ZERO); 14775295Sdes mtx_lock(&pi->pi_mutex); 14875295Sdes /* protect against possible race */ 14975295Sdes while (ppb->pb_next) 15075295Sdes ppb = ppb->pb_next; 15175295Sdes pb->pb_offset = ppb->pb_offset + PFS_BITMAP_BITS; 15275295Sdes ppb->pb_next = pb; 15375295Sdes } 15475295Sdes 15575295Sdes /* find the first free slot */ 15675295Sdes for (i = 0; i < PFS_BITMAP_SIZE; ++i) 15775295Sdes if (pb->pb_bitmap[i] != UINT_MAX) 15875295Sdes break; 15997940Sdes 16075295Sdes /* find the first available bit and flip it */ 16175295Sdes fileno = pb->pb_offset + i * PFS_SLOT_BITS; 16275295Sdes p = &pb->pb_bitmap[i]; 16375295Sdes for (i = 0; i < PFS_SLOT_BITS; ++i, ++fileno) 16475295Sdes if ((*p & (unsigned int)(1 << i)) == 0) 16575295Sdes break; 16675295Sdes KASSERT(i < PFS_SLOT_BITS, 16775295Sdes ("slot has free bits, yet doesn't")); 16875295Sdes *p |= (unsigned int)(1 << i); 16975295Sdes ++pb->pb_used; 17097940Sdes 17175295Sdes mtx_unlock(&pi->pi_mutex); 17297940Sdes 17375295Sdes return fileno; 17475295Sdes} 17575295Sdes 17675295Sdes/* 17775295Sdes * Free a file number 17875295Sdes */ 17975295Sdesstatic void 18075295Sdespfs_free_fileno(struct pfs_info *pi, u_int32_t fileno) 18175295Sdes{ 18275295Sdes struct pfs_bitmap *pb; 18375295Sdes unsigned int *p; 18475295Sdes int i; 18575295Sdes 18675295Sdes mtx_lock(&pi->pi_mutex); 18797940Sdes 18875295Sdes /* find the right page */ 18975295Sdes for (pb = pi->pi_bitmap; 19075295Sdes pb && fileno >= PFS_BITMAP_BITS; 19175295Sdes pb = pb->pb_next, fileno -= PFS_BITMAP_BITS) 19275295Sdes /* nothing */ ; 19375295Sdes KASSERT(pb, 19475295Sdes ("fileno isn't in any bitmap")); 19575295Sdes 19675295Sdes /* find the right bit in the right slot and flip it */ 19775295Sdes p = &pb->pb_bitmap[fileno / PFS_SLOT_BITS]; 19875295Sdes i = fileno % PFS_SLOT_BITS; 19975295Sdes KASSERT(*p & (unsigned int)(1 << i), 20075295Sdes ("fileno is already free")); 20175295Sdes *p &= ~((unsigned int)(1 << i)); 20275295Sdes --pb->pb_used; 20375295Sdes 20475295Sdes mtx_unlock(&pi->pi_mutex); 20577998Sdes printf("pfs_free_fileno(): reclaimed %d\n", fileno); 20675295Sdes} 20775295Sdes 20875295Sdes/* 20975295Sdes * Allocate a file number 21075295Sdes */ 21175295Sdesvoid 21275295Sdespfs_fileno_alloc(struct pfs_info *pi, struct pfs_node *pn) 21375295Sdes{ 21475295Sdes /* make sure our parent has a file number */ 21575295Sdes if (pn->pn_parent && !pn->pn_parent->pn_fileno) 21675295Sdes pfs_fileno_alloc(pi, pn->pn_parent); 21797940Sdes 21875295Sdes switch (pn->pn_type) { 21975295Sdes case pfstype_root: 22075295Sdes case pfstype_dir: 22175295Sdes case pfstype_file: 22275295Sdes case pfstype_symlink: 22377998Sdes case pfstype_procdir: 22475295Sdes pn->pn_fileno = pfs_get_fileno(pi); 22575295Sdes break; 22675295Sdes case pfstype_this: 22775295Sdes KASSERT(pn->pn_parent != NULL, 22875295Sdes ("pfstype_this node has no parent")); 22975295Sdes pn->pn_fileno = pn->pn_parent->pn_fileno; 23075295Sdes break; 23175295Sdes case pfstype_parent: 23275295Sdes KASSERT(pn->pn_parent != NULL, 23375295Sdes ("pfstype_parent node has no parent")); 23475295Sdes if (pn->pn_parent == pi->pi_root) { 23575295Sdes pn->pn_fileno = pn->pn_parent->pn_fileno; 23675295Sdes break; 23775295Sdes } 23875295Sdes KASSERT(pn->pn_parent->pn_parent != NULL, 23975295Sdes ("pfstype_parent node has no grandparent")); 24075295Sdes pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno; 24175295Sdes break; 24275295Sdes case pfstype_none: 24377998Sdes KASSERT(0, 24475295Sdes ("pfs_fileno_alloc() called for pfstype_none node")); 24575295Sdes break; 24697940Sdes } 24777998Sdes 24877998Sdes#if 0 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); 25777998Sdes#endif 25875295Sdes} 25975295Sdes 26075295Sdes/* 26175295Sdes * Release a file number 26275295Sdes */ 26375295Sdesvoid 26475295Sdespfs_fileno_free(struct pfs_info *pi, struct pfs_node *pn) 26575295Sdes{ 26675295Sdes switch (pn->pn_type) { 26775295Sdes case pfstype_root: 26875295Sdes case pfstype_dir: 26975295Sdes case pfstype_file: 27075295Sdes case pfstype_symlink: 27177998Sdes case pfstype_procdir: 27275295Sdes pfs_free_fileno(pi, pn->pn_fileno); 27375295Sdes break; 27475295Sdes case pfstype_this: 27575295Sdes case pfstype_parent: 27675295Sdes /* ignore these, as they don't "own" their file number */ 27775295Sdes break; 27875295Sdes case pfstype_none: 27977998Sdes KASSERT(0, 28075295Sdes ("pfs_fileno_free() called for pfstype_none node")); 28175295Sdes break; 28275295Sdes } 28375295Sdes} 284