158 lines
5.1 KiB
C
158 lines
5.1 KiB
C
/*-
|
|
* Copyright (c) 2003-2004 Tim J. Robbins.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
/*
|
|
* Compress 64-bit file numbers into temporary, unique 32-bit file numbers.
|
|
* This is needed because the algorithm we use to calculate these numbers
|
|
* generates 64-bit quantities, but struct dirent's d_fileno member and
|
|
* struct vnodeattr's va_fileid member only have space for 32 bits.
|
|
*
|
|
* 32-bit file numbers are generated sequentially, and stored in a
|
|
* red-black tree, indexed on 64-bit file number. The mappings do not
|
|
* persist across reboots (or unmounts); anything that relies on this
|
|
* (e.g. NFS) will not work correctly. This scheme consumes 32 bytes
|
|
* of kernel memory per file (on i386), and it may be possible for a user
|
|
* to cause a panic by creating millions of tiny files.
|
|
*
|
|
* As an optimization, we split the file number space between statically
|
|
* allocated and dynamically allocated. File numbers less than
|
|
* FILENO_FIRST_DYN are left unchanged and do not have any tree nodes
|
|
* allocated to them.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/mount.h>
|
|
|
|
#include <fs/msdosfs/bpb.h>
|
|
#include <fs/msdosfs/direntry.h>
|
|
#include <fs/msdosfs/msdosfsmount.h>
|
|
|
|
static MALLOC_DEFINE(M_MSDOSFSFILENO, "msdosfs_fileno", "MSDOSFS fileno mapping node");
|
|
|
|
RB_PROTOTYPE(msdosfs_filenotree, msdosfs_fileno, mf_tree,
|
|
msdosfs_fileno_compare)
|
|
|
|
static int msdosfs_fileno_compare(struct msdosfs_fileno *,
|
|
struct msdosfs_fileno *);
|
|
|
|
#define FILENO_FIRST_DYN 0xf0000000
|
|
|
|
/* Initialize file number mapping structures. */
|
|
void
|
|
msdosfs_fileno_init(mp)
|
|
struct mount *mp;
|
|
{
|
|
struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
|
|
|
|
RB_INIT(&pmp->pm_filenos);
|
|
pmp->pm_nfileno = FILENO_FIRST_DYN;
|
|
if (pmp->pm_HugeSectors > 0xffffffff /
|
|
(pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1)
|
|
pmp->pm_flags |= MSDOSFS_LARGEFS;
|
|
}
|
|
|
|
/* Free 32-bit file number generation structures. */
|
|
void
|
|
msdosfs_fileno_free(mp)
|
|
struct mount *mp;
|
|
{
|
|
struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
|
|
struct msdosfs_fileno *mf, *next;
|
|
|
|
for (mf = RB_MIN(msdosfs_filenotree, &pmp->pm_filenos); mf != NULL;
|
|
mf = next) {
|
|
next = RB_NEXT(msdosfs_filenotree, &pmp->pm_filenos, mf);
|
|
RB_REMOVE(msdosfs_filenotree, &pmp->pm_filenos, mf);
|
|
free(mf, M_MSDOSFSFILENO);
|
|
}
|
|
}
|
|
|
|
/* Map a 64-bit file number into a 32-bit one. */
|
|
uint32_t
|
|
msdosfs_fileno_map(mp, fileno)
|
|
struct mount *mp;
|
|
uint64_t fileno;
|
|
{
|
|
struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
|
|
struct msdosfs_fileno key, *mf, *tmf;
|
|
uint32_t mapped;
|
|
|
|
if ((pmp->pm_flags & MSDOSFS_LARGEFS) == 0) {
|
|
KASSERT((uint32_t)fileno == fileno,
|
|
("fileno >32 bits but not a large fs?"));
|
|
return ((uint32_t)fileno);
|
|
}
|
|
if (fileno < FILENO_FIRST_DYN)
|
|
return ((uint32_t)fileno);
|
|
MSDOSFS_LOCK_MP(pmp);
|
|
key.mf_fileno64 = fileno;
|
|
mf = RB_FIND(msdosfs_filenotree, &pmp->pm_filenos, &key);
|
|
if (mf != NULL) {
|
|
mapped = mf->mf_fileno32;
|
|
MSDOSFS_UNLOCK_MP(pmp);
|
|
return (mapped);
|
|
}
|
|
if (pmp->pm_nfileno < FILENO_FIRST_DYN)
|
|
panic("msdosfs_fileno_map: wraparound");
|
|
MSDOSFS_UNLOCK_MP(pmp);
|
|
mf = malloc(sizeof(*mf), M_MSDOSFSFILENO, M_WAITOK);
|
|
MSDOSFS_LOCK_MP(pmp);
|
|
tmf = RB_FIND(msdosfs_filenotree, &pmp->pm_filenos, &key);
|
|
if (tmf != NULL) {
|
|
mapped = tmf->mf_fileno32;
|
|
MSDOSFS_UNLOCK_MP(pmp);
|
|
free(mf, M_MSDOSFSFILENO);
|
|
return (mapped);
|
|
}
|
|
mf->mf_fileno64 = fileno;
|
|
mapped = mf->mf_fileno32 = pmp->pm_nfileno++;
|
|
RB_INSERT(msdosfs_filenotree, &pmp->pm_filenos, mf);
|
|
MSDOSFS_UNLOCK_MP(pmp);
|
|
return (mapped);
|
|
}
|
|
|
|
/* Compare by 64-bit file number. */
|
|
static int
|
|
msdosfs_fileno_compare(fa, fb)
|
|
struct msdosfs_fileno *fa, *fb;
|
|
{
|
|
|
|
if (fa->mf_fileno64 > fb->mf_fileno64)
|
|
return (1);
|
|
else if (fa->mf_fileno64 < fb->mf_fileno64)
|
|
return (-1);
|
|
return (0);
|
|
}
|
|
|
|
RB_GENERATE(msdosfs_filenotree, msdosfs_fileno, mf_tree,
|
|
msdosfs_fileno_compare)
|