ed1d5f95a5
With clang 15, the following -Werror warnings are produced: sys/ufs/ufs/ufs_dirhash.c:1303:16: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes] ufsdirhash_init() ^ void sys/ufs/ufs/ufs_dirhash.c:1319:18: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes] ufsdirhash_uninit() ^ void This is because ufsdirhash_init() and ufsdirhash_uninit() are declared with (void) argument lists, but defined with empty argument lists. Make the definitions match the declarations. MFC after: 3 days
1327 lines
36 KiB
C
1327 lines
36 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2001, 2002 Ian Dowse. 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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* 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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* This implements a hash-based lookup scheme for UFS directories.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ufs.h"
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#ifdef UFS_DIRHASH
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/malloc.h>
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#include <sys/fnv_hash.h>
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#include <sys/proc.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/refcount.h>
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#include <sys/sysctl.h>
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#include <sys/sx.h>
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#include <sys/eventhandler.h>
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#include <sys/time.h>
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#include <vm/uma.h>
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#include <ufs/ufs/quota.h>
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#include <ufs/ufs/inode.h>
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#include <ufs/ufs/dir.h>
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#include <ufs/ufs/dirhash.h>
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#include <ufs/ufs/extattr.h>
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#include <ufs/ufs/ufsmount.h>
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#include <ufs/ufs/ufs_extern.h>
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#define WRAPINCR(val, limit) (((val) + 1 == (limit)) ? 0 : ((val) + 1))
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#define WRAPDECR(val, limit) (((val) == 0) ? ((limit) - 1) : ((val) - 1))
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#define BLKFREE2IDX(n) ((n) > DH_NFSTATS ? DH_NFSTATS : (n))
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static MALLOC_DEFINE(M_DIRHASH, "ufs_dirhash", "UFS directory hash tables");
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static int ufs_mindirhashsize = DIRBLKSIZ * 5;
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SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_minsize, CTLFLAG_RW,
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&ufs_mindirhashsize,
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0, "minimum directory size in bytes for which to use hashed lookup");
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static int ufs_dirhashmaxmem = 2 * 1024 * 1024; /* NOTE: initial value. It is
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tuned in ufsdirhash_init() */
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SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_maxmem, CTLFLAG_RW, &ufs_dirhashmaxmem,
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0, "maximum allowed dirhash memory usage");
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static int ufs_dirhashmem;
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SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_mem, CTLFLAG_RD, &ufs_dirhashmem,
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0, "current dirhash memory usage");
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static int ufs_dirhashcheck = 0;
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SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_docheck, CTLFLAG_RW, &ufs_dirhashcheck,
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0, "enable extra sanity tests");
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static int ufs_dirhashlowmemcount = 0;
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SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_lowmemcount, CTLFLAG_RD,
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&ufs_dirhashlowmemcount, 0, "number of times low memory hook called");
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static int ufs_dirhashreclaimpercent = 10;
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static int ufsdirhash_set_reclaimpercent(SYSCTL_HANDLER_ARGS);
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SYSCTL_PROC(_vfs_ufs, OID_AUTO, dirhash_reclaimpercent,
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CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
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0, 0, ufsdirhash_set_reclaimpercent, "I",
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"set percentage of dirhash cache to be removed in low VM events");
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static int ufsdirhash_hash(struct dirhash *dh, char *name, int namelen);
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static void ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff);
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static void ufsdirhash_delslot(struct dirhash *dh, int slot);
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static int ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen,
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doff_t offset);
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static doff_t ufsdirhash_getprev(struct direct *dp, doff_t offset);
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static int ufsdirhash_recycle(int wanted);
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static void ufsdirhash_lowmem(void);
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static void ufsdirhash_free_locked(struct inode *ip);
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static uma_zone_t ufsdirhash_zone;
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#define DIRHASHLIST_LOCK() mtx_lock(&ufsdirhash_mtx)
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#define DIRHASHLIST_UNLOCK() mtx_unlock(&ufsdirhash_mtx)
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#define DIRHASH_BLKALLOC() uma_zalloc(ufsdirhash_zone, M_NOWAIT)
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#define DIRHASH_BLKFREE(ptr) uma_zfree(ufsdirhash_zone, (ptr))
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#define DIRHASH_ASSERT_LOCKED(dh) \
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sx_assert(&(dh)->dh_lock, SA_LOCKED)
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/* Dirhash list; recently-used entries are near the tail. */
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static TAILQ_HEAD(, dirhash) ufsdirhash_list;
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/* Protects: ufsdirhash_list, `dh_list' field, ufs_dirhashmem. */
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static struct mtx ufsdirhash_mtx;
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/*
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* Locking:
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*
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* The relationship between inode and dirhash is protected either by an
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* exclusive vnode lock or the vnode interlock where a shared vnode lock
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* may be used. The dirhash_mtx is acquired after the dirhash lock. To
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* handle teardown races, code wishing to lock the dirhash for an inode
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* when using a shared vnode lock must obtain a private reference on the
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* dirhash while holding the vnode interlock. They can drop it once they
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* have obtained the dirhash lock and verified that the dirhash wasn't
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* recycled while they waited for the dirhash lock.
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*
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* ufsdirhash_build() acquires a shared lock on the dirhash when it is
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* successful. This lock is released after a call to ufsdirhash_lookup().
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*
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* Functions requiring exclusive access use ufsdirhash_acquire() which may
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* free a dirhash structure that was recycled by ufsdirhash_recycle().
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*
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* The dirhash lock may be held across io operations.
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*
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* WITNESS reports a lock order reversal between the "bufwait" lock
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* and the "dirhash" lock. However, this specific reversal will not
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* cause a deadlock. To get a deadlock, one would have to lock a
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* buffer followed by the dirhash while a second thread locked a
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* buffer while holding the dirhash lock. The second order can happen
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* under a shared or exclusive vnode lock for the associated directory
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* in lookup(). The first order, however, can only happen under an
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* exclusive vnode lock (e.g. unlink(), rename(), etc.). Thus, for
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* a thread to be doing a "bufwait" -> "dirhash" order, it has to hold
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* an exclusive vnode lock. That exclusive vnode lock will prevent
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* any other threads from doing a "dirhash" -> "bufwait" order.
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*/
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static void
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ufsdirhash_hold(struct dirhash *dh)
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{
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refcount_acquire(&dh->dh_refcount);
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}
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static void
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ufsdirhash_drop(struct dirhash *dh)
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{
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if (refcount_release(&dh->dh_refcount)) {
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sx_destroy(&dh->dh_lock);
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free(dh, M_DIRHASH);
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}
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}
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/*
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* Release the lock on a dirhash.
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*/
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static void
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ufsdirhash_release(struct dirhash *dh)
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{
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sx_unlock(&dh->dh_lock);
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}
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/*
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* Either acquire an existing hash locked shared or create a new hash and
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* return it exclusively locked. May return NULL if the allocation fails.
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*
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* The vnode interlock is used to protect the i_dirhash pointer from
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* simultaneous access while only a shared vnode lock is held.
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*/
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static struct dirhash *
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ufsdirhash_create(struct inode *ip)
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{
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struct dirhash *ndh;
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struct dirhash *dh;
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struct vnode *vp;
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bool excl;
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ndh = dh = NULL;
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vp = ip->i_vnode;
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excl = false;
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for (;;) {
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/* Racy check for i_dirhash to prefetch a dirhash structure. */
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if (ip->i_dirhash == NULL && ndh == NULL) {
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ndh = malloc(sizeof *dh, M_DIRHASH,
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M_NOWAIT | M_ZERO);
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if (ndh == NULL)
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return (NULL);
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refcount_init(&ndh->dh_refcount, 1);
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/*
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* The DUPOK is to prevent warnings from the
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* sx_slock() a few lines down which is safe
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* since the duplicate lock in that case is
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* the one for this dirhash we are creating
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* now which has no external references until
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* after this function returns.
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*/
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sx_init_flags(&ndh->dh_lock, "dirhash", SX_DUPOK);
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sx_xlock(&ndh->dh_lock);
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}
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/*
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* Check i_dirhash. If it's NULL just try to use a
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* preallocated structure. If none exists loop and try again.
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*/
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VI_LOCK(vp);
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dh = ip->i_dirhash;
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if (dh == NULL) {
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ip->i_dirhash = ndh;
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VI_UNLOCK(vp);
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if (ndh == NULL)
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continue;
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return (ndh);
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}
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ufsdirhash_hold(dh);
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VI_UNLOCK(vp);
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/* Acquire a lock on existing hashes. */
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if (excl)
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sx_xlock(&dh->dh_lock);
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else
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sx_slock(&dh->dh_lock);
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/* The hash could've been recycled while we were waiting. */
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VI_LOCK(vp);
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if (ip->i_dirhash != dh) {
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VI_UNLOCK(vp);
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ufsdirhash_release(dh);
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ufsdirhash_drop(dh);
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continue;
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}
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VI_UNLOCK(vp);
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ufsdirhash_drop(dh);
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/* If the hash is still valid we've succeeded. */
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if (dh->dh_hash != NULL)
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break;
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/*
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* If the hash is NULL it has been recycled. Try to upgrade
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* so we can recreate it. If we fail the upgrade, drop our
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* lock and try again.
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*/
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if (excl || sx_try_upgrade(&dh->dh_lock))
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break;
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sx_sunlock(&dh->dh_lock);
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excl = true;
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}
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/* Free the preallocated structure if it was not necessary. */
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if (ndh) {
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ufsdirhash_release(ndh);
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ufsdirhash_drop(ndh);
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}
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return (dh);
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}
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/*
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* Acquire an exclusive lock on an existing hash. Requires an exclusive
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* vnode lock to protect the i_dirhash pointer. hashes that have been
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* recycled are reclaimed here and NULL is returned.
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*/
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static struct dirhash *
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ufsdirhash_acquire(struct inode *ip)
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{
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struct dirhash *dh;
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ASSERT_VOP_ELOCKED(ip->i_vnode, __FUNCTION__);
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dh = ip->i_dirhash;
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if (dh == NULL)
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return (NULL);
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sx_xlock(&dh->dh_lock);
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if (dh->dh_hash != NULL)
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return (dh);
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ufsdirhash_free_locked(ip);
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return (NULL);
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}
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/*
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* Acquire exclusively and free the hash pointed to by ip. Works with a
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* shared or exclusive vnode lock.
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*/
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void
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ufsdirhash_free(struct inode *ip)
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{
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struct dirhash *dh;
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struct vnode *vp;
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vp = ip->i_vnode;
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for (;;) {
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/* Grab a reference on this inode's dirhash if it has one. */
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VI_LOCK(vp);
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dh = ip->i_dirhash;
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if (dh == NULL) {
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VI_UNLOCK(vp);
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return;
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}
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ufsdirhash_hold(dh);
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VI_UNLOCK(vp);
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/* Exclusively lock the dirhash. */
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sx_xlock(&dh->dh_lock);
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/* If this dirhash still belongs to this inode, then free it. */
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VI_LOCK(vp);
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if (ip->i_dirhash == dh) {
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VI_UNLOCK(vp);
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ufsdirhash_drop(dh);
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break;
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}
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VI_UNLOCK(vp);
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/*
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* This inode's dirhash has changed while we were
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* waiting for the dirhash lock, so try again.
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*/
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ufsdirhash_release(dh);
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ufsdirhash_drop(dh);
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}
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ufsdirhash_free_locked(ip);
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}
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/*
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* Attempt to build up a hash table for the directory contents in
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* inode 'ip'. Returns 0 on success, or -1 of the operation failed.
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*/
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int
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ufsdirhash_build(struct inode *ip)
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{
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struct dirhash *dh;
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struct buf *bp = NULL;
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struct direct *ep;
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struct vnode *vp;
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doff_t bmask, pos;
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u_int dirblocks, i, narrays, nblocks, nslots;
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int j, memreqd, slot;
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/* Take care of a decreased sysctl value. */
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while (ufs_dirhashmem > ufs_dirhashmaxmem) {
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if (ufsdirhash_recycle(0) != 0)
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return (-1);
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/* Recycled enough memory, so unlock the list. */
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DIRHASHLIST_UNLOCK();
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}
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/* Check if we can/should use dirhash. */
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if (ip->i_size < ufs_mindirhashsize || OFSFMT(ip->i_vnode) ||
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ip->i_effnlink == 0) {
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if (ip->i_dirhash)
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ufsdirhash_free(ip);
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return (-1);
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}
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dh = ufsdirhash_create(ip);
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if (dh == NULL)
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return (-1);
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if (dh->dh_hash != NULL)
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return (0);
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vp = ip->i_vnode;
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/* Allocate 50% more entries than this dir size could ever need. */
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KASSERT(ip->i_size >= DIRBLKSIZ, ("ufsdirhash_build size"));
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nslots = ip->i_size / DIRECTSIZ(1);
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nslots = (nslots * 3 + 1) / 2;
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narrays = howmany(nslots, DH_NBLKOFF);
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nslots = narrays * DH_NBLKOFF;
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dirblocks = howmany(ip->i_size, DIRBLKSIZ);
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nblocks = (dirblocks * 3 + 1) / 2;
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memreqd = sizeof(*dh) + narrays * sizeof(*dh->dh_hash) +
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narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) +
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nblocks * sizeof(*dh->dh_blkfree);
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DIRHASHLIST_LOCK();
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if (memreqd + ufs_dirhashmem > ufs_dirhashmaxmem) {
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DIRHASHLIST_UNLOCK();
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if (memreqd > ufs_dirhashmaxmem / 2)
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goto fail;
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/* Try to free some space. */
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if (ufsdirhash_recycle(memreqd) != 0)
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goto fail;
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/* Enough was freed, and list has been locked. */
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}
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ufs_dirhashmem += memreqd;
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DIRHASHLIST_UNLOCK();
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/* Initialise the hash table and block statistics. */
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dh->dh_memreq = memreqd;
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dh->dh_narrays = narrays;
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dh->dh_hlen = nslots;
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dh->dh_nblk = nblocks;
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dh->dh_dirblks = dirblocks;
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for (i = 0; i < DH_NFSTATS; i++)
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dh->dh_firstfree[i] = -1;
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dh->dh_firstfree[DH_NFSTATS] = 0;
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dh->dh_hused = 0;
|
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dh->dh_seqoff = -1;
|
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dh->dh_score = DH_SCOREINIT;
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dh->dh_lastused = time_second;
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|
|
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/*
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* Use non-blocking mallocs so that we will revert to a linear
|
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* lookup on failure rather than potentially blocking forever.
|
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*/
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dh->dh_hash = malloc(narrays * sizeof(dh->dh_hash[0]),
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M_DIRHASH, M_NOWAIT | M_ZERO);
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if (dh->dh_hash == NULL)
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goto fail;
|
|
dh->dh_blkfree = malloc(nblocks * sizeof(dh->dh_blkfree[0]),
|
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M_DIRHASH, M_NOWAIT);
|
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if (dh->dh_blkfree == NULL)
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goto fail;
|
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for (i = 0; i < narrays; i++) {
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if ((dh->dh_hash[i] = DIRHASH_BLKALLOC()) == NULL)
|
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goto fail;
|
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for (j = 0; j < DH_NBLKOFF; j++)
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dh->dh_hash[i][j] = DIRHASH_EMPTY;
|
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}
|
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for (i = 0; i < dirblocks; i++)
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dh->dh_blkfree[i] = DIRBLKSIZ / DIRALIGN;
|
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bmask = vp->v_mount->mnt_stat.f_iosize - 1;
|
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pos = 0;
|
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while (pos < ip->i_size) {
|
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/* If necessary, get the next directory block. */
|
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if ((pos & bmask) == 0) {
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if (bp != NULL)
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brelse(bp);
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if (UFS_BLKATOFF(vp, (off_t)pos, NULL, &bp) != 0)
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goto fail;
|
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}
|
|
|
|
/* Add this entry to the hash. */
|
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ep = (struct direct *)((char *)bp->b_data + (pos & bmask));
|
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if (ep->d_reclen == 0 || ep->d_reclen >
|
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DIRBLKSIZ - (pos & (DIRBLKSIZ - 1))) {
|
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/* Corrupted directory. */
|
|
brelse(bp);
|
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goto fail;
|
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}
|
|
if (ep->d_ino != 0) {
|
|
/* Add the entry (simplified ufsdirhash_add). */
|
|
slot = ufsdirhash_hash(dh, ep->d_name, ep->d_namlen);
|
|
while (DH_ENTRY(dh, slot) != DIRHASH_EMPTY)
|
|
slot = WRAPINCR(slot, dh->dh_hlen);
|
|
dh->dh_hused++;
|
|
DH_ENTRY(dh, slot) = pos;
|
|
ufsdirhash_adjfree(dh, pos, -DIRSIZ(0, ep));
|
|
}
|
|
pos += ep->d_reclen;
|
|
}
|
|
|
|
if (bp != NULL)
|
|
brelse(bp);
|
|
DIRHASHLIST_LOCK();
|
|
TAILQ_INSERT_TAIL(&ufsdirhash_list, dh, dh_list);
|
|
dh->dh_onlist = 1;
|
|
DIRHASHLIST_UNLOCK();
|
|
sx_downgrade(&dh->dh_lock);
|
|
return (0);
|
|
|
|
fail:
|
|
ufsdirhash_free_locked(ip);
|
|
return (-1);
|
|
}
|
|
|
|
/*
|
|
* Free any hash table associated with inode 'ip'.
|
|
*/
|
|
static void
|
|
ufsdirhash_free_locked(struct inode *ip)
|
|
{
|
|
struct dirhash *dh;
|
|
struct vnode *vp;
|
|
int i;
|
|
|
|
DIRHASH_ASSERT_LOCKED(ip->i_dirhash);
|
|
|
|
/*
|
|
* Clear the pointer in the inode to prevent new threads from
|
|
* finding the dead structure.
|
|
*/
|
|
vp = ip->i_vnode;
|
|
VI_LOCK(vp);
|
|
dh = ip->i_dirhash;
|
|
ip->i_dirhash = NULL;
|
|
VI_UNLOCK(vp);
|
|
|
|
/*
|
|
* Remove the hash from the list since we are going to free its
|
|
* memory.
|
|
*/
|
|
DIRHASHLIST_LOCK();
|
|
if (dh->dh_onlist)
|
|
TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list);
|
|
ufs_dirhashmem -= dh->dh_memreq;
|
|
DIRHASHLIST_UNLOCK();
|
|
|
|
/*
|
|
* At this point, any waiters for the lock should hold their
|
|
* own reference on the dirhash structure. They will drop
|
|
* that reference once they grab the vnode interlock and see
|
|
* that ip->i_dirhash is NULL.
|
|
*/
|
|
sx_xunlock(&dh->dh_lock);
|
|
|
|
/*
|
|
* Handle partially recycled as well as fully constructed hashes.
|
|
*/
|
|
if (dh->dh_hash != NULL) {
|
|
for (i = 0; i < dh->dh_narrays; i++)
|
|
if (dh->dh_hash[i] != NULL)
|
|
DIRHASH_BLKFREE(dh->dh_hash[i]);
|
|
free(dh->dh_hash, M_DIRHASH);
|
|
if (dh->dh_blkfree != NULL)
|
|
free(dh->dh_blkfree, M_DIRHASH);
|
|
}
|
|
|
|
/*
|
|
* Drop the inode's reference to the data structure.
|
|
*/
|
|
ufsdirhash_drop(dh);
|
|
}
|
|
|
|
/*
|
|
* Find the offset of the specified name within the given inode.
|
|
* Returns 0 on success, ENOENT if the entry does not exist, or
|
|
* EJUSTRETURN if the caller should revert to a linear search.
|
|
*
|
|
* If successful, the directory offset is stored in *offp, and a
|
|
* pointer to a struct buf containing the entry is stored in *bpp. If
|
|
* prevoffp is non-NULL, the offset of the previous entry within
|
|
* the DIRBLKSIZ-sized block is stored in *prevoffp (if the entry
|
|
* is the first in a block, the start of the block is used).
|
|
*
|
|
* Must be called with the hash locked. Returns with the hash unlocked.
|
|
*/
|
|
int
|
|
ufsdirhash_lookup(struct inode *ip, char *name, int namelen, doff_t *offp,
|
|
struct buf **bpp, doff_t *prevoffp)
|
|
{
|
|
struct dirhash *dh, *dh_next;
|
|
struct direct *dp;
|
|
struct vnode *vp;
|
|
struct buf *bp;
|
|
doff_t blkoff, bmask, offset, prevoff, seqoff;
|
|
int i, slot;
|
|
int error;
|
|
|
|
dh = ip->i_dirhash;
|
|
KASSERT(dh != NULL && dh->dh_hash != NULL,
|
|
("ufsdirhash_lookup: Invalid dirhash %p\n", dh));
|
|
DIRHASH_ASSERT_LOCKED(dh);
|
|
/*
|
|
* Move this dirhash towards the end of the list if it has a
|
|
* score higher than the next entry, and acquire the dh_lock.
|
|
*/
|
|
DIRHASHLIST_LOCK();
|
|
if (TAILQ_NEXT(dh, dh_list) != NULL) {
|
|
/*
|
|
* If the new score will be greater than that of the next
|
|
* entry, then move this entry past it. With both mutexes
|
|
* held, dh_next won't go away, but its dh_score could
|
|
* change; that's not important since it is just a hint.
|
|
*/
|
|
if ((dh_next = TAILQ_NEXT(dh, dh_list)) != NULL &&
|
|
dh->dh_score >= dh_next->dh_score) {
|
|
KASSERT(dh->dh_onlist, ("dirhash: not on list"));
|
|
TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list);
|
|
TAILQ_INSERT_AFTER(&ufsdirhash_list, dh_next, dh,
|
|
dh_list);
|
|
}
|
|
}
|
|
/* Update the score. */
|
|
if (dh->dh_score < DH_SCOREMAX)
|
|
dh->dh_score++;
|
|
|
|
/* Update last used time. */
|
|
dh->dh_lastused = time_second;
|
|
DIRHASHLIST_UNLOCK();
|
|
|
|
vp = ip->i_vnode;
|
|
bmask = vp->v_mount->mnt_stat.f_iosize - 1;
|
|
blkoff = -1;
|
|
bp = NULL;
|
|
seqoff = dh->dh_seqoff;
|
|
restart:
|
|
slot = ufsdirhash_hash(dh, name, namelen);
|
|
|
|
if (seqoff != -1) {
|
|
/*
|
|
* Sequential access optimisation. seqoff contains the
|
|
* offset of the directory entry immediately following
|
|
* the last entry that was looked up. Check if this offset
|
|
* appears in the hash chain for the name we are looking for.
|
|
*/
|
|
for (i = slot; (offset = DH_ENTRY(dh, i)) != DIRHASH_EMPTY;
|
|
i = WRAPINCR(i, dh->dh_hlen))
|
|
if (offset == seqoff)
|
|
break;
|
|
if (offset == seqoff) {
|
|
/*
|
|
* We found an entry with the expected offset. This
|
|
* is probably the entry we want, but if not, the
|
|
* code below will retry.
|
|
*/
|
|
slot = i;
|
|
} else
|
|
seqoff = -1;
|
|
}
|
|
|
|
for (; (offset = DH_ENTRY(dh, slot)) != DIRHASH_EMPTY;
|
|
slot = WRAPINCR(slot, dh->dh_hlen)) {
|
|
if (offset == DIRHASH_DEL)
|
|
continue;
|
|
if (offset < 0 || offset >= ip->i_size)
|
|
panic("ufsdirhash_lookup: bad offset in hash array");
|
|
if ((offset & ~bmask) != blkoff) {
|
|
if (bp != NULL)
|
|
brelse(bp);
|
|
blkoff = offset & ~bmask;
|
|
if (UFS_BLKATOFF(vp, (off_t)blkoff, NULL, &bp) != 0) {
|
|
error = EJUSTRETURN;
|
|
goto fail;
|
|
}
|
|
}
|
|
KASSERT(bp != NULL, ("no buffer allocated"));
|
|
dp = (struct direct *)(bp->b_data + (offset & bmask));
|
|
if (dp->d_reclen == 0 || dp->d_reclen >
|
|
DIRBLKSIZ - (offset & (DIRBLKSIZ - 1))) {
|
|
/* Corrupted directory. */
|
|
error = EJUSTRETURN;
|
|
goto fail;
|
|
}
|
|
if (dp->d_namlen == namelen &&
|
|
bcmp(dp->d_name, name, namelen) == 0) {
|
|
/* Found. Get the prev offset if needed. */
|
|
if (prevoffp != NULL) {
|
|
if (offset & (DIRBLKSIZ - 1)) {
|
|
prevoff = ufsdirhash_getprev(dp,
|
|
offset);
|
|
if (prevoff == -1) {
|
|
error = EJUSTRETURN;
|
|
goto fail;
|
|
}
|
|
} else
|
|
prevoff = offset;
|
|
*prevoffp = prevoff;
|
|
}
|
|
|
|
/* Update offset. */
|
|
dh->dh_seqoff = offset + DIRSIZ(0, dp);
|
|
*bpp = bp;
|
|
*offp = offset;
|
|
ufsdirhash_release(dh);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* When the name doesn't match in the sequential
|
|
* optimization case, go back and search normally.
|
|
*/
|
|
if (seqoff != -1) {
|
|
seqoff = -1;
|
|
goto restart;
|
|
}
|
|
}
|
|
error = ENOENT;
|
|
fail:
|
|
ufsdirhash_release(dh);
|
|
if (bp != NULL)
|
|
brelse(bp);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Find a directory block with room for 'slotneeded' bytes. Returns
|
|
* the offset of the directory entry that begins the free space.
|
|
* This will either be the offset of an existing entry that has free
|
|
* space at the end, or the offset of an entry with d_ino == 0 at
|
|
* the start of a DIRBLKSIZ block.
|
|
*
|
|
* To use the space, the caller may need to compact existing entries in
|
|
* the directory. The total number of bytes in all of the entries involved
|
|
* in the compaction is stored in *slotsize. In other words, all of
|
|
* the entries that must be compacted are exactly contained in the
|
|
* region beginning at the returned offset and spanning *slotsize bytes.
|
|
*
|
|
* Returns -1 if no space was found, indicating that the directory
|
|
* must be extended.
|
|
*/
|
|
doff_t
|
|
ufsdirhash_findfree(struct inode *ip, int slotneeded, int *slotsize)
|
|
{
|
|
struct direct *dp;
|
|
struct dirhash *dh;
|
|
struct buf *bp;
|
|
doff_t pos, slotstart;
|
|
int dirblock, error, freebytes, i;
|
|
|
|
dh = ip->i_dirhash;
|
|
KASSERT(dh != NULL && dh->dh_hash != NULL,
|
|
("ufsdirhash_findfree: Invalid dirhash %p\n", dh));
|
|
DIRHASH_ASSERT_LOCKED(dh);
|
|
|
|
/* Find a directory block with the desired free space. */
|
|
dirblock = -1;
|
|
for (i = howmany(slotneeded, DIRALIGN); i <= DH_NFSTATS; i++)
|
|
if ((dirblock = dh->dh_firstfree[i]) != -1)
|
|
break;
|
|
if (dirblock == -1)
|
|
return (-1);
|
|
|
|
KASSERT(dirblock < dh->dh_nblk &&
|
|
dh->dh_blkfree[dirblock] >= howmany(slotneeded, DIRALIGN),
|
|
("ufsdirhash_findfree: bad stats"));
|
|
pos = dirblock * DIRBLKSIZ;
|
|
error = UFS_BLKATOFF(ip->i_vnode, (off_t)pos, (char **)&dp, &bp);
|
|
if (error)
|
|
return (-1);
|
|
|
|
/* Find the first entry with free space. */
|
|
for (i = 0; i < DIRBLKSIZ; ) {
|
|
if (dp->d_reclen == 0) {
|
|
brelse(bp);
|
|
return (-1);
|
|
}
|
|
if (dp->d_ino == 0 || dp->d_reclen > DIRSIZ(0, dp))
|
|
break;
|
|
i += dp->d_reclen;
|
|
dp = (struct direct *)((char *)dp + dp->d_reclen);
|
|
}
|
|
if (i > DIRBLKSIZ) {
|
|
brelse(bp);
|
|
return (-1);
|
|
}
|
|
slotstart = pos + i;
|
|
|
|
/* Find the range of entries needed to get enough space */
|
|
freebytes = 0;
|
|
while (i < DIRBLKSIZ && freebytes < slotneeded) {
|
|
freebytes += dp->d_reclen;
|
|
if (dp->d_ino != 0)
|
|
freebytes -= DIRSIZ(0, dp);
|
|
if (dp->d_reclen == 0) {
|
|
brelse(bp);
|
|
return (-1);
|
|
}
|
|
i += dp->d_reclen;
|
|
dp = (struct direct *)((char *)dp + dp->d_reclen);
|
|
}
|
|
if (i > DIRBLKSIZ) {
|
|
brelse(bp);
|
|
return (-1);
|
|
}
|
|
if (freebytes < slotneeded)
|
|
panic("ufsdirhash_findfree: free mismatch");
|
|
brelse(bp);
|
|
*slotsize = pos + i - slotstart;
|
|
return (slotstart);
|
|
}
|
|
|
|
/*
|
|
* Return the start of the unused space at the end of a directory, or
|
|
* -1 if there are no trailing unused blocks.
|
|
*/
|
|
doff_t
|
|
ufsdirhash_enduseful(struct inode *ip)
|
|
{
|
|
|
|
struct dirhash *dh;
|
|
int i;
|
|
|
|
dh = ip->i_dirhash;
|
|
DIRHASH_ASSERT_LOCKED(dh);
|
|
KASSERT(dh != NULL && dh->dh_hash != NULL,
|
|
("ufsdirhash_enduseful: Invalid dirhash %p\n", dh));
|
|
|
|
if (dh->dh_blkfree[dh->dh_dirblks - 1] != DIRBLKSIZ / DIRALIGN)
|
|
return (-1);
|
|
|
|
for (i = dh->dh_dirblks - 1; i >= 0; i--)
|
|
if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN)
|
|
break;
|
|
|
|
return ((doff_t)(i + 1) * DIRBLKSIZ);
|
|
}
|
|
|
|
/*
|
|
* Insert information into the hash about a new directory entry. dirp
|
|
* points to a struct direct containing the entry, and offset specifies
|
|
* the offset of this entry.
|
|
*/
|
|
void
|
|
ufsdirhash_add(struct inode *ip, struct direct *dirp, doff_t offset)
|
|
{
|
|
struct dirhash *dh;
|
|
int slot;
|
|
|
|
if ((dh = ufsdirhash_acquire(ip)) == NULL)
|
|
return;
|
|
|
|
KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ,
|
|
("ufsdirhash_add: bad offset"));
|
|
/*
|
|
* Normal hash usage is < 66%. If the usage gets too high then
|
|
* remove the hash entirely and let it be rebuilt later.
|
|
*/
|
|
if (dh->dh_hused >= (dh->dh_hlen * 3) / 4) {
|
|
ufsdirhash_free_locked(ip);
|
|
return;
|
|
}
|
|
|
|
/* Find a free hash slot (empty or deleted), and add the entry. */
|
|
slot = ufsdirhash_hash(dh, dirp->d_name, dirp->d_namlen);
|
|
while (DH_ENTRY(dh, slot) >= 0)
|
|
slot = WRAPINCR(slot, dh->dh_hlen);
|
|
if (DH_ENTRY(dh, slot) == DIRHASH_EMPTY)
|
|
dh->dh_hused++;
|
|
DH_ENTRY(dh, slot) = offset;
|
|
|
|
/* Update last used time. */
|
|
dh->dh_lastused = time_second;
|
|
|
|
/* Update the per-block summary info. */
|
|
ufsdirhash_adjfree(dh, offset, -DIRSIZ(0, dirp));
|
|
ufsdirhash_release(dh);
|
|
}
|
|
|
|
/*
|
|
* Remove the specified directory entry from the hash. The entry to remove
|
|
* is defined by the name in `dirp', which must exist at the specified
|
|
* `offset' within the directory.
|
|
*/
|
|
void
|
|
ufsdirhash_remove(struct inode *ip, struct direct *dirp, doff_t offset)
|
|
{
|
|
struct dirhash *dh;
|
|
int slot;
|
|
|
|
if ((dh = ufsdirhash_acquire(ip)) == NULL)
|
|
return;
|
|
|
|
KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ,
|
|
("ufsdirhash_remove: bad offset"));
|
|
/* Find the entry */
|
|
slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, offset);
|
|
|
|
/* Remove the hash entry. */
|
|
ufsdirhash_delslot(dh, slot);
|
|
|
|
/* Update the per-block summary info. */
|
|
ufsdirhash_adjfree(dh, offset, DIRSIZ(0, dirp));
|
|
ufsdirhash_release(dh);
|
|
}
|
|
|
|
/*
|
|
* Change the offset associated with a directory entry in the hash. Used
|
|
* when compacting directory blocks.
|
|
*/
|
|
void
|
|
ufsdirhash_move(struct inode *ip, struct direct *dirp, doff_t oldoff,
|
|
doff_t newoff)
|
|
{
|
|
struct dirhash *dh;
|
|
int slot;
|
|
|
|
if ((dh = ufsdirhash_acquire(ip)) == NULL)
|
|
return;
|
|
|
|
KASSERT(oldoff < dh->dh_dirblks * DIRBLKSIZ &&
|
|
newoff < dh->dh_dirblks * DIRBLKSIZ,
|
|
("ufsdirhash_move: bad offset"));
|
|
/* Find the entry, and update the offset. */
|
|
slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, oldoff);
|
|
DH_ENTRY(dh, slot) = newoff;
|
|
ufsdirhash_release(dh);
|
|
}
|
|
|
|
/*
|
|
* Inform dirhash that the directory has grown by one block that
|
|
* begins at offset (i.e. the new length is offset + DIRBLKSIZ).
|
|
*/
|
|
void
|
|
ufsdirhash_newblk(struct inode *ip, doff_t offset)
|
|
{
|
|
struct dirhash *dh;
|
|
int block;
|
|
|
|
if ((dh = ufsdirhash_acquire(ip)) == NULL)
|
|
return;
|
|
|
|
KASSERT(offset == dh->dh_dirblks * DIRBLKSIZ,
|
|
("ufsdirhash_newblk: bad offset"));
|
|
block = offset / DIRBLKSIZ;
|
|
if (block >= dh->dh_nblk) {
|
|
/* Out of space; must rebuild. */
|
|
ufsdirhash_free_locked(ip);
|
|
return;
|
|
}
|
|
dh->dh_dirblks = block + 1;
|
|
|
|
/* Account for the new free block. */
|
|
dh->dh_blkfree[block] = DIRBLKSIZ / DIRALIGN;
|
|
if (dh->dh_firstfree[DH_NFSTATS] == -1)
|
|
dh->dh_firstfree[DH_NFSTATS] = block;
|
|
ufsdirhash_release(dh);
|
|
}
|
|
|
|
/*
|
|
* Inform dirhash that the directory is being truncated.
|
|
*/
|
|
void
|
|
ufsdirhash_dirtrunc(struct inode *ip, doff_t offset)
|
|
{
|
|
struct dirhash *dh;
|
|
int block, i;
|
|
|
|
if ((dh = ufsdirhash_acquire(ip)) == NULL)
|
|
return;
|
|
|
|
KASSERT(offset <= dh->dh_dirblks * DIRBLKSIZ,
|
|
("ufsdirhash_dirtrunc: bad offset"));
|
|
block = howmany(offset, DIRBLKSIZ);
|
|
/*
|
|
* If the directory shrinks to less than 1/8 of dh_nblk blocks
|
|
* (about 20% of its original size due to the 50% extra added in
|
|
* ufsdirhash_build) then free it, and let the caller rebuild
|
|
* if necessary.
|
|
*/
|
|
if (block < dh->dh_nblk / 8 && dh->dh_narrays > 1) {
|
|
ufsdirhash_free_locked(ip);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Remove any `first free' information pertaining to the
|
|
* truncated blocks. All blocks we're removing should be
|
|
* completely unused.
|
|
*/
|
|
if (dh->dh_firstfree[DH_NFSTATS] >= block)
|
|
dh->dh_firstfree[DH_NFSTATS] = -1;
|
|
for (i = block; i < dh->dh_dirblks; i++)
|
|
if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN)
|
|
panic("ufsdirhash_dirtrunc: blocks in use");
|
|
for (i = 0; i < DH_NFSTATS; i++)
|
|
if (dh->dh_firstfree[i] >= block)
|
|
panic("ufsdirhash_dirtrunc: first free corrupt");
|
|
dh->dh_dirblks = block;
|
|
ufsdirhash_release(dh);
|
|
}
|
|
|
|
/*
|
|
* Debugging function to check that the dirhash information about
|
|
* a directory block matches its actual contents. Panics if a mismatch
|
|
* is detected.
|
|
*
|
|
* On entry, `buf' should point to the start of an in-core
|
|
* DIRBLKSIZ-sized directory block, and `offset' should contain the
|
|
* offset from the start of the directory of that block.
|
|
*/
|
|
void
|
|
ufsdirhash_checkblock(struct inode *ip, char *buf, doff_t offset)
|
|
{
|
|
struct dirhash *dh;
|
|
struct direct *dp;
|
|
int block, ffslot, i, nfree;
|
|
|
|
if (!ufs_dirhashcheck)
|
|
return;
|
|
if ((dh = ufsdirhash_acquire(ip)) == NULL)
|
|
return;
|
|
|
|
block = offset / DIRBLKSIZ;
|
|
if ((offset & (DIRBLKSIZ - 1)) != 0 || block >= dh->dh_dirblks)
|
|
panic("ufsdirhash_checkblock: bad offset");
|
|
|
|
nfree = 0;
|
|
for (i = 0; i < DIRBLKSIZ; i += dp->d_reclen) {
|
|
dp = (struct direct *)(buf + i);
|
|
if (dp->d_reclen == 0 || i + dp->d_reclen > DIRBLKSIZ)
|
|
panic("ufsdirhash_checkblock: bad dir");
|
|
|
|
if (dp->d_ino == 0) {
|
|
#if 0
|
|
/*
|
|
* XXX entries with d_ino == 0 should only occur
|
|
* at the start of a DIRBLKSIZ block. However the
|
|
* ufs code is tolerant of such entries at other
|
|
* offsets, and fsck does not fix them.
|
|
*/
|
|
if (i != 0)
|
|
panic("ufsdirhash_checkblock: bad dir inode");
|
|
#endif
|
|
nfree += dp->d_reclen;
|
|
continue;
|
|
}
|
|
|
|
/* Check that the entry exists (will panic if it doesn't). */
|
|
ufsdirhash_findslot(dh, dp->d_name, dp->d_namlen, offset + i);
|
|
|
|
nfree += dp->d_reclen - DIRSIZ(0, dp);
|
|
}
|
|
if (i != DIRBLKSIZ)
|
|
panic("ufsdirhash_checkblock: bad dir end");
|
|
|
|
if (dh->dh_blkfree[block] * DIRALIGN != nfree)
|
|
panic("ufsdirhash_checkblock: bad free count");
|
|
|
|
ffslot = BLKFREE2IDX(nfree / DIRALIGN);
|
|
for (i = 0; i <= DH_NFSTATS; i++)
|
|
if (dh->dh_firstfree[i] == block && i != ffslot)
|
|
panic("ufsdirhash_checkblock: bad first-free");
|
|
if (dh->dh_firstfree[ffslot] == -1)
|
|
panic("ufsdirhash_checkblock: missing first-free entry");
|
|
ufsdirhash_release(dh);
|
|
}
|
|
|
|
/*
|
|
* Hash the specified filename into a dirhash slot.
|
|
*/
|
|
static int
|
|
ufsdirhash_hash(struct dirhash *dh, char *name, int namelen)
|
|
{
|
|
u_int32_t hash;
|
|
|
|
/*
|
|
* We hash the name and then some other bit of data that is
|
|
* invariant over the dirhash's lifetime. Otherwise names
|
|
* differing only in the last byte are placed close to one
|
|
* another in the table, which is bad for linear probing.
|
|
*/
|
|
hash = fnv_32_buf(name, namelen, FNV1_32_INIT);
|
|
hash = fnv_32_buf(&dh, sizeof(dh), hash);
|
|
return (hash % dh->dh_hlen);
|
|
}
|
|
|
|
/*
|
|
* Adjust the number of free bytes in the block containing `offset'
|
|
* by the value specified by `diff'.
|
|
*
|
|
* The caller must ensure we have exclusive access to `dh'; normally
|
|
* that means that dh_lock should be held, but this is also called
|
|
* from ufsdirhash_build() where exclusive access can be assumed.
|
|
*/
|
|
static void
|
|
ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff)
|
|
{
|
|
int block, i, nfidx, ofidx;
|
|
|
|
/* Update the per-block summary info. */
|
|
block = offset / DIRBLKSIZ;
|
|
KASSERT(block < dh->dh_nblk && block < dh->dh_dirblks,
|
|
("dirhash bad offset"));
|
|
ofidx = BLKFREE2IDX(dh->dh_blkfree[block]);
|
|
dh->dh_blkfree[block] = (int)dh->dh_blkfree[block] + (diff / DIRALIGN);
|
|
nfidx = BLKFREE2IDX(dh->dh_blkfree[block]);
|
|
|
|
/* Update the `first free' list if necessary. */
|
|
if (ofidx != nfidx) {
|
|
/* If removing, scan forward for the next block. */
|
|
if (dh->dh_firstfree[ofidx] == block) {
|
|
for (i = block + 1; i < dh->dh_dirblks; i++)
|
|
if (BLKFREE2IDX(dh->dh_blkfree[i]) == ofidx)
|
|
break;
|
|
dh->dh_firstfree[ofidx] = (i < dh->dh_dirblks) ? i : -1;
|
|
}
|
|
|
|
/* Make this the new `first free' if necessary */
|
|
if (dh->dh_firstfree[nfidx] > block ||
|
|
dh->dh_firstfree[nfidx] == -1)
|
|
dh->dh_firstfree[nfidx] = block;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Find the specified name which should have the specified offset.
|
|
* Returns a slot number, and panics on failure.
|
|
*
|
|
* `dh' must be locked on entry and remains so on return.
|
|
*/
|
|
static int
|
|
ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen, doff_t offset)
|
|
{
|
|
int slot;
|
|
|
|
DIRHASH_ASSERT_LOCKED(dh);
|
|
|
|
/* Find the entry. */
|
|
KASSERT(dh->dh_hused < dh->dh_hlen, ("dirhash find full"));
|
|
slot = ufsdirhash_hash(dh, name, namelen);
|
|
while (DH_ENTRY(dh, slot) != offset &&
|
|
DH_ENTRY(dh, slot) != DIRHASH_EMPTY)
|
|
slot = WRAPINCR(slot, dh->dh_hlen);
|
|
if (DH_ENTRY(dh, slot) != offset)
|
|
panic("ufsdirhash_findslot: '%.*s' not found", namelen, name);
|
|
|
|
return (slot);
|
|
}
|
|
|
|
/*
|
|
* Remove the entry corresponding to the specified slot from the hash array.
|
|
*
|
|
* `dh' must be locked on entry and remains so on return.
|
|
*/
|
|
static void
|
|
ufsdirhash_delslot(struct dirhash *dh, int slot)
|
|
{
|
|
int i;
|
|
|
|
DIRHASH_ASSERT_LOCKED(dh);
|
|
|
|
/* Mark the entry as deleted. */
|
|
DH_ENTRY(dh, slot) = DIRHASH_DEL;
|
|
|
|
/* If this is the end of a chain of DIRHASH_DEL slots, remove them. */
|
|
for (i = slot; DH_ENTRY(dh, i) == DIRHASH_DEL; )
|
|
i = WRAPINCR(i, dh->dh_hlen);
|
|
if (DH_ENTRY(dh, i) == DIRHASH_EMPTY) {
|
|
i = WRAPDECR(i, dh->dh_hlen);
|
|
while (DH_ENTRY(dh, i) == DIRHASH_DEL) {
|
|
DH_ENTRY(dh, i) = DIRHASH_EMPTY;
|
|
dh->dh_hused--;
|
|
i = WRAPDECR(i, dh->dh_hlen);
|
|
}
|
|
KASSERT(dh->dh_hused >= 0, ("ufsdirhash_delslot neg hlen"));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Given a directory entry and its offset, find the offset of the
|
|
* previous entry in the same DIRBLKSIZ-sized block. Returns an
|
|
* offset, or -1 if there is no previous entry in the block or some
|
|
* other problem occurred.
|
|
*/
|
|
static doff_t
|
|
ufsdirhash_getprev(struct direct *dirp, doff_t offset)
|
|
{
|
|
struct direct *dp;
|
|
char *blkbuf;
|
|
doff_t blkoff, prevoff;
|
|
int entrypos, i;
|
|
|
|
blkoff = rounddown2(offset, DIRBLKSIZ); /* offset of start of block */
|
|
entrypos = offset & (DIRBLKSIZ - 1); /* entry relative to block */
|
|
blkbuf = (char *)dirp - entrypos;
|
|
prevoff = blkoff;
|
|
|
|
/* If `offset' is the start of a block, there is no previous entry. */
|
|
if (entrypos == 0)
|
|
return (-1);
|
|
|
|
/* Scan from the start of the block until we get to the entry. */
|
|
for (i = 0; i < entrypos; i += dp->d_reclen) {
|
|
dp = (struct direct *)(blkbuf + i);
|
|
if (dp->d_reclen == 0 || i + dp->d_reclen > entrypos)
|
|
return (-1); /* Corrupted directory. */
|
|
prevoff = blkoff + i;
|
|
}
|
|
return (prevoff);
|
|
}
|
|
|
|
/*
|
|
* Delete the given dirhash and reclaim its memory. Assumes that
|
|
* ufsdirhash_list is locked, and leaves it locked. Also assumes
|
|
* that dh is locked. Returns the amount of memory freed.
|
|
*/
|
|
static int
|
|
ufsdirhash_destroy(struct dirhash *dh)
|
|
{
|
|
doff_t **hash;
|
|
u_int8_t *blkfree;
|
|
int i, mem, narrays;
|
|
|
|
KASSERT(dh->dh_hash != NULL, ("dirhash: NULL hash on list"));
|
|
|
|
/* Remove it from the list and detach its memory. */
|
|
TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list);
|
|
dh->dh_onlist = 0;
|
|
hash = dh->dh_hash;
|
|
dh->dh_hash = NULL;
|
|
blkfree = dh->dh_blkfree;
|
|
dh->dh_blkfree = NULL;
|
|
narrays = dh->dh_narrays;
|
|
mem = dh->dh_memreq;
|
|
dh->dh_memreq = 0;
|
|
|
|
/* Unlock dirhash and free the detached memory. */
|
|
ufsdirhash_release(dh);
|
|
for (i = 0; i < narrays; i++)
|
|
DIRHASH_BLKFREE(hash[i]);
|
|
free(hash, M_DIRHASH);
|
|
free(blkfree, M_DIRHASH);
|
|
|
|
/* Account for the returned memory. */
|
|
ufs_dirhashmem -= mem;
|
|
|
|
return (mem);
|
|
}
|
|
|
|
/*
|
|
* Try to free up `wanted' bytes by stealing memory from existing
|
|
* dirhashes. Returns zero with list locked if successful.
|
|
*/
|
|
static int
|
|
ufsdirhash_recycle(int wanted)
|
|
{
|
|
struct dirhash *dh;
|
|
|
|
DIRHASHLIST_LOCK();
|
|
dh = TAILQ_FIRST(&ufsdirhash_list);
|
|
while (wanted + ufs_dirhashmem > ufs_dirhashmaxmem) {
|
|
/* Decrement the score; only recycle if it becomes zero. */
|
|
if (dh == NULL || --dh->dh_score > 0) {
|
|
DIRHASHLIST_UNLOCK();
|
|
return (-1);
|
|
}
|
|
/*
|
|
* If we can't lock it it's in use and we don't want to
|
|
* recycle it anyway.
|
|
*/
|
|
if (!sx_try_xlock(&dh->dh_lock)) {
|
|
dh = TAILQ_NEXT(dh, dh_list);
|
|
continue;
|
|
}
|
|
|
|
ufsdirhash_destroy(dh);
|
|
|
|
/* Repeat if necessary. */
|
|
dh = TAILQ_FIRST(&ufsdirhash_list);
|
|
}
|
|
/* Success; return with list locked. */
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Callback that frees some dirhashes when the system is low on virtual memory.
|
|
*/
|
|
static void
|
|
ufsdirhash_lowmem(void)
|
|
{
|
|
struct dirhash *dh, *dh_temp;
|
|
int memfreed, memwanted;
|
|
|
|
ufs_dirhashlowmemcount++;
|
|
memfreed = 0;
|
|
memwanted = ufs_dirhashmem * ufs_dirhashreclaimpercent / 100;
|
|
|
|
DIRHASHLIST_LOCK();
|
|
|
|
/*
|
|
* Reclaim up to memwanted from the oldest dirhashes. This will allow
|
|
* us to make some progress when the system is running out of memory
|
|
* without compromising the dinamicity of maximum age. If the situation
|
|
* does not improve lowmem will be eventually retriggered and free some
|
|
* other entry in the cache. The entries on the head of the list should
|
|
* be the oldest. If during list traversal we can't get a lock on the
|
|
* dirhash, it will be skipped.
|
|
*/
|
|
TAILQ_FOREACH_SAFE(dh, &ufsdirhash_list, dh_list, dh_temp) {
|
|
if (sx_try_xlock(&dh->dh_lock))
|
|
memfreed += ufsdirhash_destroy(dh);
|
|
if (memfreed >= memwanted)
|
|
break;
|
|
}
|
|
DIRHASHLIST_UNLOCK();
|
|
}
|
|
|
|
static int
|
|
ufsdirhash_set_reclaimpercent(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error, v;
|
|
|
|
v = ufs_dirhashreclaimpercent;
|
|
error = sysctl_handle_int(oidp, &v, v, req);
|
|
if (error)
|
|
return (error);
|
|
if (req->newptr == NULL)
|
|
return (error);
|
|
if (v == ufs_dirhashreclaimpercent)
|
|
return (0);
|
|
|
|
/* Refuse invalid percentages */
|
|
if (v < 0 || v > 100)
|
|
return (EINVAL);
|
|
ufs_dirhashreclaimpercent = v;
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
ufsdirhash_init(void)
|
|
{
|
|
ufs_dirhashmaxmem = lmax(roundup(hibufspace / 64, PAGE_SIZE),
|
|
2 * 1024 * 1024);
|
|
|
|
ufsdirhash_zone = uma_zcreate("DIRHASH", DH_NBLKOFF * sizeof(doff_t),
|
|
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
|
|
mtx_init(&ufsdirhash_mtx, "dirhash list", NULL, MTX_DEF);
|
|
TAILQ_INIT(&ufsdirhash_list);
|
|
|
|
/* Register a callback function to handle low memory signals */
|
|
EVENTHANDLER_REGISTER(vm_lowmem, ufsdirhash_lowmem, NULL,
|
|
EVENTHANDLER_PRI_FIRST);
|
|
}
|
|
|
|
void
|
|
ufsdirhash_uninit(void)
|
|
{
|
|
KASSERT(TAILQ_EMPTY(&ufsdirhash_list), ("ufsdirhash_uninit"));
|
|
uma_zdestroy(ufsdirhash_zone);
|
|
mtx_destroy(&ufsdirhash_mtx);
|
|
}
|
|
|
|
#endif /* UFS_DIRHASH */
|