285 lines
6.8 KiB
C
285 lines
6.8 KiB
C
/*-
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* Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/sysctl.h>
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#include <machine/limits.h>
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#include <fs/pseudofs/pseudofs.h>
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#include <fs/pseudofs/pseudofs_internal.h>
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static MALLOC_DEFINE(M_PFSFILENO, "pfs_fileno", "pseudofs fileno bitmap");
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static struct mtx pfs_fileno_mutex;
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#define PFS_BITMAP_SIZE 4096
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#define PFS_SLOT_BITS (int)(sizeof(unsigned int) * CHAR_BIT)
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#define PFS_BITMAP_BITS (PFS_BITMAP_SIZE * PFS_SLOT_BITS)
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struct pfs_bitmap {
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u_int32_t pb_offset;
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int pb_used;
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unsigned int pb_bitmap[PFS_BITMAP_SIZE];
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struct pfs_bitmap *pb_next;
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};
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/*
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* Initialization
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*/
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void
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pfs_fileno_load(void)
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{
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mtx_init(&pfs_fileno_mutex, "pseudofs_fileno", NULL, MTX_DEF);
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}
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/*
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* Teardown
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*/
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void
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pfs_fileno_unload(void)
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{
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mtx_destroy(&pfs_fileno_mutex);
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}
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/*
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* Initialize fileno bitmap
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*/
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void
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pfs_fileno_init(struct pfs_info *pi)
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{
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struct pfs_bitmap *pb;
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MALLOC(pb, struct pfs_bitmap *, sizeof *pb,
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M_PFSFILENO, M_WAITOK|M_ZERO);
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mtx_lock(&pi->pi_mutex);
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pb->pb_bitmap[0] = 07;
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pb->pb_used = 3;
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pi->pi_bitmap = pb;
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pi->pi_root->pn_fileno = 2;
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mtx_unlock(&pi->pi_mutex);
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}
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/*
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* Tear down fileno bitmap
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*/
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void
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pfs_fileno_uninit(struct pfs_info *pi)
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{
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struct pfs_bitmap *pb, *npb;
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int used;
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mtx_lock(&pi->pi_mutex);
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pb = pi->pi_bitmap;
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pi->pi_bitmap = NULL;
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mtx_unlock(&pi->pi_mutex);
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for (used = 0; pb; pb = npb) {
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npb = pb->pb_next;
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used += pb->pb_used;
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FREE(pb, M_PFSFILENO);
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}
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#if 0
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/* we currently don't reclaim filenos */
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if (used > 2)
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printf("WARNING: %d file numbers still in use\n", used);
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#endif
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}
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/*
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* Get the next available file number
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*/
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static u_int32_t
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pfs_get_fileno(struct pfs_info *pi)
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{
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struct pfs_bitmap *pb, *ppb;
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u_int32_t fileno;
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unsigned int *p;
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int i;
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mtx_lock(&pi->pi_mutex);
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/* look for the first page with free bits */
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for (ppb = NULL, pb = pi->pi_bitmap; pb; ppb = pb, pb = pb->pb_next)
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if (pb->pb_used != PFS_BITMAP_BITS)
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break;
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/* out of pages? */
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if (pb == NULL) {
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mtx_unlock(&pi->pi_mutex);
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MALLOC(pb, struct pfs_bitmap *, sizeof *pb,
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M_PFSFILENO, M_WAITOK|M_ZERO);
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mtx_lock(&pi->pi_mutex);
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/* protect against possible race */
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while (ppb->pb_next)
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ppb = ppb->pb_next;
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pb->pb_offset = ppb->pb_offset + PFS_BITMAP_BITS;
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ppb->pb_next = pb;
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}
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/* find the first free slot */
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for (i = 0; i < PFS_BITMAP_SIZE; ++i)
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if (pb->pb_bitmap[i] != UINT_MAX)
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break;
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/* find the first available bit and flip it */
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fileno = pb->pb_offset + i * PFS_SLOT_BITS;
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p = &pb->pb_bitmap[i];
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for (i = 0; i < PFS_SLOT_BITS; ++i, ++fileno)
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if ((*p & (unsigned int)(1 << i)) == 0)
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break;
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KASSERT(i < PFS_SLOT_BITS,
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("slot has free bits, yet doesn't"));
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*p |= (unsigned int)(1 << i);
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++pb->pb_used;
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mtx_unlock(&pi->pi_mutex);
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return fileno;
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}
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/*
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* Free a file number
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*/
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static void
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pfs_free_fileno(struct pfs_info *pi, u_int32_t fileno)
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{
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struct pfs_bitmap *pb;
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unsigned int *p;
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int i;
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mtx_lock(&pi->pi_mutex);
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/* find the right page */
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for (pb = pi->pi_bitmap;
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pb && fileno >= PFS_BITMAP_BITS;
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pb = pb->pb_next, fileno -= PFS_BITMAP_BITS)
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/* nothing */ ;
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KASSERT(pb,
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("fileno isn't in any bitmap"));
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/* find the right bit in the right slot and flip it */
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p = &pb->pb_bitmap[fileno / PFS_SLOT_BITS];
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i = fileno % PFS_SLOT_BITS;
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KASSERT(*p & (unsigned int)(1 << i),
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("fileno is already free"));
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*p &= ~((unsigned int)(1 << i));
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--pb->pb_used;
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mtx_unlock(&pi->pi_mutex);
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printf("pfs_free_fileno(): reclaimed %d\n", fileno);
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}
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/*
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* Allocate a file number
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*/
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void
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pfs_fileno_alloc(struct pfs_info *pi, struct pfs_node *pn)
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{
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/* make sure our parent has a file number */
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if (pn->pn_parent && !pn->pn_parent->pn_fileno)
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pfs_fileno_alloc(pi, pn->pn_parent);
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switch (pn->pn_type) {
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case pfstype_root:
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case pfstype_dir:
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case pfstype_file:
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case pfstype_symlink:
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case pfstype_procdir:
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pn->pn_fileno = pfs_get_fileno(pi);
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break;
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case pfstype_this:
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KASSERT(pn->pn_parent != NULL,
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("pfstype_this node has no parent"));
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pn->pn_fileno = pn->pn_parent->pn_fileno;
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break;
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case pfstype_parent:
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KASSERT(pn->pn_parent != NULL,
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("pfstype_parent node has no parent"));
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if (pn->pn_parent == pi->pi_root) {
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pn->pn_fileno = pn->pn_parent->pn_fileno;
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break;
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}
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KASSERT(pn->pn_parent->pn_parent != NULL,
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("pfstype_parent node has no grandparent"));
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pn->pn_fileno = pn->pn_parent->pn_parent->pn_fileno;
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break;
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case pfstype_none:
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KASSERT(0,
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("pfs_fileno_alloc() called for pfstype_none node"));
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break;
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}
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#if 0
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printf("pfs_fileno_alloc(): %s: ", pi->pi_name);
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if (pn->pn_parent) {
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if (pn->pn_parent->pn_parent) {
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printf("%s/", pn->pn_parent->pn_parent->pn_name);
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}
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printf("%s/", pn->pn_parent->pn_name);
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}
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printf("%s -> %d\n", pn->pn_name, pn->pn_fileno);
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#endif
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}
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/*
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* Release a file number
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*/
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void
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pfs_fileno_free(struct pfs_info *pi, struct pfs_node *pn)
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{
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switch (pn->pn_type) {
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case pfstype_root:
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case pfstype_dir:
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case pfstype_file:
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case pfstype_symlink:
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case pfstype_procdir:
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pfs_free_fileno(pi, pn->pn_fileno);
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break;
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case pfstype_this:
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case pfstype_parent:
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/* ignore these, as they don't "own" their file number */
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break;
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case pfstype_none:
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KASSERT(0,
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("pfs_fileno_free() called for pfstype_none node"));
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break;
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}
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}
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