pseudofs_fileno.c revision 78073
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 78073 2001-06-11 15:04:48Z des $ 2975295Sdes */ 3075295Sdes 3175295Sdes#include <sys/param.h> 3275295Sdes#include <sys/kernel.h> 3375295Sdes#include <sys/systm.h> 3478073Sdes#include <sys/lock.h> 3575295Sdes#include <sys/malloc.h> 3675295Sdes#include <sys/mount.h> 3777965Sdes#include <sys/mutex.h> 3875295Sdes#include <sys/proc.h> 3975295Sdes#include <sys/sbuf.h> 4075295Sdes#include <sys/sysctl.h> 4175295Sdes 4275295Sdes#include <machine/limits.h> 4375295Sdes 4475295Sdes#include <fs/pseudofs/pseudofs.h> 4575295Sdes#include <fs/pseudofs/pseudofs_internal.h> 4675295Sdes 4777998Sdesstatic MALLOC_DEFINE(M_PFSFILENO, "pfs_fileno", "pseudofs fileno bitmap"); 4875295Sdes 4975295Sdesstatic struct mtx pfs_fileno_mutex; 5075295Sdes 5175295Sdes#define PFS_BITMAP_SIZE 4096 5277998Sdes#define PFS_SLOT_BITS (int)(sizeof(unsigned int) * CHAR_BIT) 5375295Sdes#define PFS_BITMAP_BITS (PFS_BITMAP_SIZE * PFS_SLOT_BITS) 5475295Sdesstruct pfs_bitmap { 5575295Sdes u_int32_t pb_offset; 5675295Sdes int pb_used; 5775295Sdes unsigned int pb_bitmap[PFS_BITMAP_SIZE]; 5875295Sdes struct pfs_bitmap *pb_next; 5975295Sdes}; 6075295Sdes 6175295Sdes/* 6275295Sdes * Initialization 6375295Sdes */ 6475295Sdesvoid 6575295Sdespfs_fileno_load(void) 6675295Sdes{ 6775295Sdes mtx_init(&pfs_fileno_mutex, "pseudofs_fileno", MTX_DEF); 6875295Sdes} 6975295Sdes 7075295Sdes/* 7175295Sdes * Teardown 7275295Sdes */ 7375295Sdesvoid 7475295Sdespfs_fileno_unload(void) 7575295Sdes{ 7675295Sdes mtx_destroy(&pfs_fileno_mutex); 7775295Sdes} 7875295Sdes 7975295Sdes/* 8075295Sdes * Initialize fileno bitmap 8175295Sdes */ 8275295Sdesvoid 8375295Sdespfs_fileno_init(struct pfs_info *pi) 8475295Sdes{ 8575295Sdes struct pfs_bitmap *pb; 8675295Sdes 8775295Sdes MALLOC(pb, struct pfs_bitmap *, sizeof *pb, 8875295Sdes M_PFSFILENO, M_WAITOK|M_ZERO); 8975295Sdes 9075295Sdes mtx_lock(&pi->pi_mutex); 9175295Sdes 9275295Sdes pb->pb_bitmap[0] = 07; 9375295Sdes pb->pb_used = 3; 9475295Sdes pi->pi_bitmap = pb; 9575295Sdes pi->pi_root->pn_fileno = 2; 9675295Sdes 9775295Sdes mtx_unlock(&pi->pi_mutex); 9875295Sdes} 9975295Sdes 10075295Sdes/* 10175295Sdes * Tear down fileno bitmap 10275295Sdes */ 10375295Sdesvoid 10475295Sdespfs_fileno_uninit(struct pfs_info *pi) 10575295Sdes{ 10675295Sdes struct pfs_bitmap *pb, *npb; 10775295Sdes int used; 10875295Sdes 10975295Sdes mtx_lock(&pi->pi_mutex); 11075295Sdes 11175295Sdes pb = pi->pi_bitmap; 11275295Sdes pi->pi_bitmap = NULL; 11375295Sdes 11475295Sdes mtx_unlock(&pi->pi_mutex); 11575295Sdes 11675295Sdes for (used = 0; pb; pb = npb) { 11775295Sdes npb = pb->pb_next; 11875295Sdes used += pb->pb_used; 11975295Sdes FREE(pb, M_PFSFILENO); 12075295Sdes } 12177998Sdes#if 0 12277998Sdes /* we currently don't reclaim filenos */ 12375295Sdes if (used > 2) 12475295Sdes printf("WARNING: %d file numbers still in use\n", used); 12577998Sdes#endif 12675295Sdes} 12775295Sdes 12875295Sdes/* 12975295Sdes * Get the next available file number 13075295Sdes */ 13175295Sdesstatic u_int32_t 13275295Sdespfs_get_fileno(struct pfs_info *pi) 13375295Sdes{ 13475295Sdes struct pfs_bitmap *pb, *ppb; 13575295Sdes u_int32_t fileno; 13675295Sdes unsigned int *p; 13775295Sdes int i; 13875295Sdes 13975295Sdes mtx_lock(&pi->pi_mutex); 14075295Sdes 14175295Sdes /* look for the first page with free bits */ 14275295Sdes for (ppb = NULL, pb = pi->pi_bitmap; pb; ppb = pb, pb = pb->pb_next) 14375295Sdes if (pb->pb_used != PFS_BITMAP_BITS) 14475295Sdes break; 14575295Sdes 14675295Sdes /* out of pages? */ 14775295Sdes if (pb == NULL) { 14875295Sdes mtx_unlock(&pi->pi_mutex); 14975295Sdes MALLOC(pb, struct pfs_bitmap *, sizeof *pb, 15075295Sdes M_PFSFILENO, M_WAITOK|M_ZERO); 15175295Sdes mtx_lock(&pi->pi_mutex); 15275295Sdes /* protect against possible race */ 15375295Sdes while (ppb->pb_next) 15475295Sdes ppb = ppb->pb_next; 15575295Sdes pb->pb_offset = ppb->pb_offset + PFS_BITMAP_BITS; 15675295Sdes ppb->pb_next = pb; 15775295Sdes } 15875295Sdes 15975295Sdes /* find the first free slot */ 16075295Sdes for (i = 0; i < PFS_BITMAP_SIZE; ++i) 16175295Sdes if (pb->pb_bitmap[i] != UINT_MAX) 16275295Sdes break; 16375295Sdes 16475295Sdes /* find the first available bit and flip it */ 16575295Sdes fileno = pb->pb_offset + i * PFS_SLOT_BITS; 16675295Sdes p = &pb->pb_bitmap[i]; 16775295Sdes for (i = 0; i < PFS_SLOT_BITS; ++i, ++fileno) 16875295Sdes if ((*p & (unsigned int)(1 << i)) == 0) 16975295Sdes break; 17075295Sdes KASSERT(i < PFS_SLOT_BITS, 17175295Sdes ("slot has free bits, yet doesn't")); 17275295Sdes *p |= (unsigned int)(1 << i); 17375295Sdes ++pb->pb_used; 17475295Sdes 17575295Sdes mtx_unlock(&pi->pi_mutex); 17675295Sdes 17775295Sdes return fileno; 17875295Sdes} 17975295Sdes 18075295Sdes/* 18175295Sdes * Free a file number 18275295Sdes */ 18375295Sdesstatic void 18475295Sdespfs_free_fileno(struct pfs_info *pi, u_int32_t fileno) 18575295Sdes{ 18675295Sdes struct pfs_bitmap *pb; 18775295Sdes unsigned int *p; 18875295Sdes int i; 18975295Sdes 19075295Sdes mtx_lock(&pi->pi_mutex); 19175295Sdes 19275295Sdes /* find the right page */ 19375295Sdes for (pb = pi->pi_bitmap; 19475295Sdes pb && fileno >= PFS_BITMAP_BITS; 19575295Sdes pb = pb->pb_next, fileno -= PFS_BITMAP_BITS) 19675295Sdes /* nothing */ ; 19775295Sdes KASSERT(pb, 19875295Sdes ("fileno isn't in any bitmap")); 19975295Sdes 20075295Sdes /* find the right bit in the right slot and flip it */ 20175295Sdes p = &pb->pb_bitmap[fileno / PFS_SLOT_BITS]; 20275295Sdes i = fileno % PFS_SLOT_BITS; 20375295Sdes KASSERT(*p & (unsigned int)(1 << i), 20475295Sdes ("fileno is already free")); 20575295Sdes *p &= ~((unsigned int)(1 << i)); 20675295Sdes --pb->pb_used; 20775295Sdes 20875295Sdes mtx_unlock(&pi->pi_mutex); 20977998Sdes printf("pfs_free_fileno(): reclaimed %d\n", fileno); 21075295Sdes} 21175295Sdes 21275295Sdes/* 21375295Sdes * Allocate a file number 21475295Sdes */ 21575295Sdesvoid 21675295Sdespfs_fileno_alloc(struct pfs_info *pi, struct pfs_node *pn) 21775295Sdes{ 21875295Sdes /* make sure our parent has a file number */ 21975295Sdes if (pn->pn_parent && !pn->pn_parent->pn_fileno) 22075295Sdes pfs_fileno_alloc(pi, pn->pn_parent); 22175295Sdes 22275295Sdes switch (pn->pn_type) { 22375295Sdes case pfstype_root: 22475295Sdes case pfstype_dir: 22575295Sdes case pfstype_file: 22675295Sdes case pfstype_symlink: 22777998Sdes case pfstype_procdir: 22875295Sdes pn->pn_fileno = pfs_get_fileno(pi); 22975295Sdes break; 23075295Sdes case pfstype_this: 23175295Sdes KASSERT(pn->pn_parent != NULL, 23275295Sdes ("pfstype_this node has no parent")); 23375295Sdes pn->pn_fileno = pn->pn_parent->pn_fileno; 23475295Sdes break; 23575295Sdes case pfstype_parent: 23675295Sdes KASSERT(pn->pn_parent != NULL, 23775295Sdes ("pfstype_parent node has no parent")); 23875295Sdes if (pn->pn_parent == pi->pi_root) { 23975295Sdes pn->pn_fileno = pn->pn_parent->pn_fileno; 24075295Sdes break; 24175295Sdes } 24275295Sdes KASSERT(pn->pn_parent->pn_parent != NULL, 24375295Sdes ("pfstype_parent node has no grandparent")); 24475295Sdes pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno; 24575295Sdes break; 24675295Sdes case pfstype_none: 24777998Sdes KASSERT(0, 24875295Sdes ("pfs_fileno_alloc() called for pfstype_none node")); 24975295Sdes break; 25075295Sdes } 25177998Sdes 25277998Sdes#if 0 25375295Sdes printf("pfs_fileno_alloc(): %s: ", pi->pi_name); 25475295Sdes if (pn->pn_parent) { 25575295Sdes if (pn->pn_parent->pn_parent) { 25675295Sdes printf("%s/", pn->pn_parent->pn_parent->pn_name); 25775295Sdes } 25875295Sdes printf("%s/", pn->pn_parent->pn_name); 25975295Sdes } 26075295Sdes printf("%s -> %d\n", pn->pn_name, pn->pn_fileno); 26177998Sdes#endif 26275295Sdes} 26375295Sdes 26475295Sdes/* 26575295Sdes * Release a file number 26675295Sdes */ 26775295Sdesvoid 26875295Sdespfs_fileno_free(struct pfs_info *pi, struct pfs_node *pn) 26975295Sdes{ 27075295Sdes switch (pn->pn_type) { 27175295Sdes case pfstype_root: 27275295Sdes case pfstype_dir: 27375295Sdes case pfstype_file: 27475295Sdes case pfstype_symlink: 27577998Sdes case pfstype_procdir: 27675295Sdes pfs_free_fileno(pi, pn->pn_fileno); 27775295Sdes break; 27875295Sdes case pfstype_this: 27975295Sdes case pfstype_parent: 28075295Sdes /* ignore these, as they don't "own" their file number */ 28175295Sdes break; 28275295Sdes case pfstype_none: 28377998Sdes KASSERT(0, 28475295Sdes ("pfs_fileno_free() called for pfstype_none node")); 28575295Sdes break; 28675295Sdes } 28775295Sdes} 288