fs/cachefs/cachefs_module.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include <sys/errno.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <rpc/types.h>
#include <sys/mode.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/fs/cachefs_fs.h>

/*
 * This is the loadable module wrapper.
 */
#include <sys/systm.h>
#include <sys/modctl.h>
#include <sys/syscall.h>

extern time_t time;

static int cachefs_init(int, char *);
static void cachefs_fini();

static int cachefs_unloadable = 0; /* tunable */
static boolean_t cachefs_up = B_FALSE;

uint_t cachefs_max_apop_inqueue = CACHEFS_MAX_APOP_INQUEUE;

/*
 * this is a list of possible hash table sizes, for the `double
 * hashing' algorithm described in rosen's `elementary number theory
 * and its applications'.  minimally, this needs to be a list of
 * increasing prime integers, terminated by a 0.  ideally, they should
 * be the larger of twin primes; i.e. P and P-2 are both prime.
 */

int cachefs_hash_sizes[] = {5, 2029, 4093, 8089, 16363, 32719, 0};

/*
 * Module linkage information for the kernel.
 */

static vfsdef_t vfs_z = {
	VFSDEF_VERSION,
	CACHEFS_BASETYPE,
	cachefs_init,
	VSW_CANREMOUNT,
	NULL
};

static struct modlfs modlfs = {
	&mod_fsops,
	"cache filesystem",
	&vfs_z
};

static struct modlinkage modlinkage = {
	MODREV_1, (void *)&modlfs, NULL
};

char _depends_on[] = "strmod/rpcmod";

int
_init(void)
{
	int status;

	status = mod_install(&modlinkage);
	if (status != 0) {
		/*
		 * Could not load module, clean up the work performed
		 * by cachefs_init() which was indirectly called by
		 * mod_installfs() which in turn was called by mod_install().
		 */
		cachefs_fini();
	}

	return (status);
}

int
_info(struct modinfo *modinfop)
{
	return (mod_info(&modlinkage, modinfop));
}

int
_fini(void)
{
	int status;

	if (!cachefs_unloadable)
		return (EBUSY);

	if ((status = mod_remove(&modlinkage)) == 0) {
		/*
		 * Module has been unloaded, now clean up
		 */
		cachefs_fini();
	}

	return (status);
}

extern kmutex_t cachefs_cachelock;		/* Cache list mutex */
extern kmutex_t cachefs_newnum_lock;
extern kmutex_t cachefs_kstat_key_lock;
extern kmutex_t cachefs_rename_lock;
extern kmutex_t cachefs_minor_lock;	/* Lock for minor device map */
extern kmutex_t cachefs_kmem_lock;
extern kmutex_t cachefs_async_lock;	/* global async work count */
extern major_t cachefs_major;

/*
 * Cache initialization routine.  This routine should only be called
 * once.  It performs the following tasks:
 *	- Initalize all global locks
 * 	- Call sub-initialization routines (localize access to variables)
 */
static int
cachefs_init(int fstyp, char *name)
{
	kstat_t *ksp;
	int error;

	ASSERT(cachefs_up == B_FALSE);

	error = cachefs_init_vfsops(fstyp);
	if (error != 0)
		return (error);

	error = cachefs_init_vnops(name);
	if (error != 0)
		return (error);

	mutex_init(&cachefs_cachelock, NULL, MUTEX_DEFAULT, NULL);
	mutex_init(&cachefs_newnum_lock, NULL, MUTEX_DEFAULT, NULL);
	mutex_init(&cachefs_kstat_key_lock, NULL, MUTEX_DEFAULT, NULL);
	mutex_init(&cachefs_kmem_lock, NULL, MUTEX_DEFAULT, NULL);
	mutex_init(&cachefs_rename_lock, NULL, MUTEX_DEFAULT, NULL);
	mutex_init(&cachefs_minor_lock, NULL, MUTEX_DEFAULT, NULL);
	mutex_init(&cachefs_async_lock, NULL, MUTEX_DEFAULT, NULL);
#ifdef CFSRLDEBUG
	mutex_init(&cachefs_rl_debug_mutex, NULL, MUTEX_DEFAULT, NULL);
#endif /* CFSRLDEBUG */

	/*
	 * set up kmem_cache entities
	 */

	cachefs_cnode_cache = kmem_cache_create("cachefs_cnode_cache",
	    sizeof (struct cnode), 0, NULL, NULL, NULL, NULL, NULL, 0);
	cachefs_req_cache = kmem_cache_create("cachefs_async_request",
	    sizeof (struct cachefs_req), 0,
	    cachefs_req_create, cachefs_req_destroy, NULL, NULL, NULL, 0);
	cachefs_fscache_cache = kmem_cache_create("cachefs_fscache",
	    sizeof (fscache_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
	cachefs_filegrp_cache = kmem_cache_create("cachefs_filegrp",
	    sizeof (filegrp_t), 0,
	    filegrp_cache_create, filegrp_cache_destroy, NULL, NULL, NULL, 0);
	cachefs_cache_kmcache = kmem_cache_create("cachefs_cache_t",
	    sizeof (cachefscache_t), 0, NULL, NULL, NULL, NULL, NULL, 0);

	/*
	 * set up the cachefs.0.key kstat
	 */

	cachefs_kstat_key = NULL;
	cachefs_kstat_key_n = 0;
	ksp = kstat_create("cachefs", 0, "key", "misc", KSTAT_TYPE_RAW, 1,
	    KSTAT_FLAG_VIRTUAL | KSTAT_FLAG_VAR_SIZE);
	if (ksp != NULL) {
		ksp->ks_data = &cachefs_kstat_key;
		ksp->ks_update = cachefs_kstat_key_update;
		ksp->ks_snapshot = cachefs_kstat_key_snapshot;
		ksp->ks_lock = &cachefs_kstat_key_lock;
		kstat_install(ksp);
	}

	/*
	 * Assign unique major number for all nfs mounts
	 */

	if ((cachefs_major = getudev()) == -1) {
		cmn_err(CE_WARN,
			"cachefs: init: can't get unique device number");
		cachefs_major = 0;
	}
	cachefs_up = B_TRUE;
#ifdef CFSRLDEBUG
	cachefs_dbvalid = time;
#endif /* CFSRLDEBUG */

	return (0);
}

/*
 * Cache clean up routine. This routine is called if mod_install() failed
 * and we have to clean up because the module could not be installed,
 * or by _fini() when we're unloading the module.
 */
static void
cachefs_fini()
{
	extern int cachefsfstyp;
	extern struct vnodeops *cachefs_vnodeops;

	if (cachefs_up == B_FALSE) {
		/*
		 * cachefs_init() was not called on _init(),
		 * nothing to deallocate.
		 */
		return;
	}

	/*
	 * Clean up cachefs.0.key kstat.
	 * Currently, you can only do a
	 * modunload if cachefs_unloadable is nonzero, and that's
	 * pretty much just for debugging.  however, if there ever
	 * comes a day when cachefs is more freely unloadable
	 * (e.g. the modunload daemon can do it normally), then we'll
	 * have to make changes in the stats_ API.  this is because a
	 * stats_cookie_t holds the id # derived from here, and it
	 * will all go away at modunload time.  thus, the API will
	 * need to somehow be more robust than is currently necessary.
	 */
	kstat_delete_byname("cachefs", 0, "key");

	if (cachefs_kstat_key != NULL) {
		cachefs_kstat_key_t *key;
		int i;

		for (i = 0; i < cachefs_kstat_key_n; i++) {
			key = cachefs_kstat_key + i;

			cachefs_kmem_free((void *)(uintptr_t)key->ks_mountpoint,
			    strlen((char *)(uintptr_t)key->ks_mountpoint) + 1);
			cachefs_kmem_free((void *)(uintptr_t)key->ks_backfs,
			    strlen((char *)(uintptr_t)key->ks_backfs) + 1);
			cachefs_kmem_free((void *)(uintptr_t)key->ks_cachedir,
			    strlen((char *)(uintptr_t)key->ks_cachedir) + 1);
			cachefs_kmem_free((void *)(uintptr_t)key->ks_cacheid,
			    strlen((char *)(uintptr_t)key->ks_cacheid) + 1);
		}

		cachefs_kmem_free(cachefs_kstat_key,
		    cachefs_kstat_key_n * sizeof (*cachefs_kstat_key));
	}

	/*
	 * Clean up kmem_cache entities
	 */
	kmem_cache_destroy(cachefs_cache_kmcache);
	kmem_cache_destroy(cachefs_filegrp_cache);
	kmem_cache_destroy(cachefs_fscache_cache);
	kmem_cache_destroy(cachefs_req_cache);
	kmem_cache_destroy(cachefs_cnode_cache);
#ifdef CFSRLDEBUG
	if (cachefs_rl_debug_cache != NULL)
		kmem_cache_destroy(cachefs_rl_debug_cache);
#endif /* CFSRLDEBUG */

	/*
	 * Clean up the operations structures
	 */
	(void) vfs_freevfsops_by_type(cachefsfstyp);
	vn_freevnodeops(cachefs_vnodeops);

	/*
	 * Destroy mutexes
	 */
#ifdef CFSRLDEBUG
	mutex_destroy(&cachefs_rl_debug_mutex);
#endif /* CFSRLDEBUG */
	mutex_destroy(&cachefs_async_lock);
	mutex_destroy(&cachefs_minor_lock);
	mutex_destroy(&cachefs_rename_lock);
	mutex_destroy(&cachefs_kmem_lock);
	mutex_destroy(&cachefs_kstat_key_lock);
	mutex_destroy(&cachefs_newnum_lock);
	mutex_destroy(&cachefs_cachelock);
}