cifsfs.c

Linux内核自带的cifs模块

#endif /* CONFIG_CIFS_EXPERIMENTAL */
};

const struct file_operations cifs_dir_ops = {
	.readdir = cifs_readdir,
	.release = cifs_closedir,
	.read    = generic_read_dir,
#ifdef CONFIG_CIFS_EXPERIMENTAL
	.dir_notify = cifs_dir_notify,
#endif /* CONFIG_CIFS_EXPERIMENTAL */
	.ioctl  = cifs_ioctl,
};

#ifndef SLAB_MEM_SPREAD
#define SLAB_MEM_SPREAD 0
#endif

static void
cifs_init_once(void *inode, struct kmem_cache *cachep, unsigned long flags)
{
	struct cifsInodeInfo *cifsi = inode;

	inode_init_once(&cifsi->vfs_inode);
	INIT_LIST_HEAD(&cifsi->lockList);
}

static int
cifs_init_inodecache(void)
{
	cifs_inode_cachep = kmem_cache_create("cifs_inode_cache",
					      sizeof(struct cifsInodeInfo),
					      0, (SLAB_RECLAIM_ACCOUNT|
						SLAB_MEM_SPREAD),
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 22)
					      cifs_init_once);
#else
					      cifs_init_once, NULL);
#endif
	if (cifs_inode_cachep == NULL)
		return -ENOMEM;

	return 0;
}

static void
cifs_destroy_inodecache(void)
{
	kmem_cache_destroy(cifs_inode_cachep);
}

static int
cifs_init_request_bufs(void)
{
	if (CIFSMaxBufSize < 8192) {
	/* Buffer size can not be smaller than 2 * PATH_MAX since maximum
	Unicode path name has to fit in any SMB/CIFS path based frames */
		CIFSMaxBufSize = 8192;
	} else if (CIFSMaxBufSize > 1024*127) {
		CIFSMaxBufSize = 1024 * 127;
	} else {
		CIFSMaxBufSize &= 0x1FE00; /* Round size to even 512 byte mult*/
	}
/*	cERROR(1,("CIFSMaxBufSize %d 0x%x",CIFSMaxBufSize,CIFSMaxBufSize)); */
	cifs_req_cachep = kmem_cache_create("cifs_request",
					    CIFSMaxBufSize +
					    MAX_CIFS_HDR_SIZE, 0,
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 22)
					    SLAB_HWCACHE_ALIGN, NULL);
#else
					    SLAB_HWCACHE_ALIGN, NULL, NULL);
#endif
	if (cifs_req_cachep == NULL)
		return -ENOMEM;

	if (cifs_min_rcv < 1)
		cifs_min_rcv = 1;
	else if (cifs_min_rcv > 64) {
		cifs_min_rcv = 64;
		cERROR(1, ("cifs_min_rcv set to maximum (64)"));
	}

	cifs_req_poolp = mempool_create_slab_pool(cifs_min_rcv,
						  cifs_req_cachep);

	if (cifs_req_poolp == NULL) {
		kmem_cache_destroy(cifs_req_cachep);
		return -ENOMEM;
	}
	/* MAX_CIFS_SMALL_BUFFER_SIZE bytes is enough for most SMB responses and
	almost all handle based requests (but not write response, nor is it
	sufficient for path based requests).  A smaller size would have
	been more efficient (compacting multiple slab items on one 4k page)
	for the case in which debug was on, but this larger size allows
	more SMBs to use small buffer alloc and is still much more
	efficient to alloc 1 per page off the slab compared to 17K (5page)
	alloc of large cifs buffers even when page debugging is on */
	cifs_sm_req_cachep = kmem_cache_create("cifs_small_rq",
			MAX_CIFS_SMALL_BUFFER_SIZE, 0, SLAB_HWCACHE_ALIGN,
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 22)
			NULL);
#else
			NULL, NULL);
#endif
	if (cifs_sm_req_cachep == NULL) {
		mempool_destroy(cifs_req_poolp);
		kmem_cache_destroy(cifs_req_cachep);
		return -ENOMEM;
	}

	if (cifs_min_small < 2)
		cifs_min_small = 2;
	else if (cifs_min_small > 256) {
		cifs_min_small = 256;
		cFYI(1, ("cifs_min_small set to maximum (256)"));
	}

	cifs_sm_req_poolp = mempool_create_slab_pool(cifs_min_small,
						     cifs_sm_req_cachep);

	if (cifs_sm_req_poolp == NULL) {
		mempool_destroy(cifs_req_poolp);
		kmem_cache_destroy(cifs_req_cachep);
		kmem_cache_destroy(cifs_sm_req_cachep);
		return -ENOMEM;
	}

	return 0;
}

static void
cifs_destroy_request_bufs(void)
{
	mempool_destroy(cifs_req_poolp);
	kmem_cache_destroy(cifs_req_cachep);
	mempool_destroy(cifs_sm_req_poolp);
	kmem_cache_destroy(cifs_sm_req_cachep);
}

static int
cifs_init_mids(void)
{
	cifs_mid_cachep = kmem_cache_create("cifs_mpx_ids",
					    sizeof(struct mid_q_entry), 0,
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 22)
					    SLAB_HWCACHE_ALIGN, NULL);
#else
					    SLAB_HWCACHE_ALIGN, NULL, NULL);
#endif
	if (cifs_mid_cachep == NULL)
		return -ENOMEM;

	/* 3 is a reasonable minimum number of simultaneous operations */
	cifs_mid_poolp = mempool_create_slab_pool(3, cifs_mid_cachep);
	if (cifs_mid_poolp == NULL) {
		kmem_cache_destroy(cifs_mid_cachep);
		return -ENOMEM;
	}

	cifs_oplock_cachep = kmem_cache_create("cifs_oplock_structs",
					sizeof(struct oplock_q_entry), 0,
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 22)
					SLAB_HWCACHE_ALIGN, NULL);
#else
					SLAB_HWCACHE_ALIGN, NULL, NULL);
#endif
	if (cifs_oplock_cachep == NULL) {
		mempool_destroy(cifs_mid_poolp);
		kmem_cache_destroy(cifs_mid_cachep);
		return -ENOMEM;
	}

	return 0;
}

static void
cifs_destroy_mids(void)
{
	mempool_destroy(cifs_mid_poolp);
	kmem_cache_destroy(cifs_mid_cachep);
	kmem_cache_destroy(cifs_oplock_cachep);
}

static int cifs_oplock_thread(void *dummyarg)
{
	struct oplock_q_entry *oplock_item;
	struct cifsTconInfo *pTcon;
	struct inode *inode;
	__u16  netfid;
	int rc;

#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 22)
	set_freezable();
#endif
	do {
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 12)
		if (try_to_freeze())
			continue;
#endif

		spin_lock(&GlobalMid_Lock);
		if (list_empty(&GlobalOplock_Q)) {
			spin_unlock(&GlobalMid_Lock);
			set_current_state(TASK_INTERRUPTIBLE);
			schedule_timeout(39*HZ);
		} else {
			oplock_item = list_entry(GlobalOplock_Q.next,
				struct oplock_q_entry, qhead);
			if (oplock_item) {
				cFYI(1, ("found oplock item to write out"));
				pTcon = oplock_item->tcon;
				inode = oplock_item->pinode;
				netfid = oplock_item->netfid;
				spin_unlock(&GlobalMid_Lock);
				DeleteOplockQEntry(oplock_item);
				/* can not grab inode sem here since it would
				deadlock when oplock received on delete
				since vfs_unlink holds the i_mutex across
				the call */
				/* mutex_lock(&inode->i_mutex);*/
				if (S_ISREG(inode->i_mode)) {
					rc =
					   filemap_fdatawrite(inode->i_mapping);
					if (CIFS_I(inode)->clientCanCacheRead
									 == 0) {
						filemap_fdatawait(inode->i_mapping);
						invalidate_remote_inode(inode);
					}
				} else
					rc = 0;
				/* mutex_unlock(&inode->i_mutex);*/
				if (rc)
					CIFS_I(inode)->write_behind_rc = rc;
				cFYI(1, ("Oplock flush inode %p rc %d",
					inode, rc));

				/* releasing stale oplock after recent reconnect
				of smb session using a now incorrect file
				handle is not a data integrity issue but do
				not bother sending an oplock release if session
				to server still is disconnected since oplock
				already released by the server in that case */
				if (pTcon->tidStatus != CifsNeedReconnect) {
				    rc = CIFSSMBLock(0, pTcon, netfid,
					    0 /* len */ , 0 /* offset */, 0,
					    0, LOCKING_ANDX_OPLOCK_RELEASE,
					    0 /* wait flag */);
					cFYI(1, ("Oplock release rc = %d", rc));
				}
			} else
				spin_unlock(&GlobalMid_Lock);
			set_current_state(TASK_INTERRUPTIBLE);
			schedule_timeout(1);  /* yield in case q were corrupt */
		}
	} while (!kthread_should_stop());

	return 0;
}

static int cifs_dnotify_thread(void *dummyarg)
{
	struct list_head *tmp;
	struct cifsSesInfo *ses;

	do {
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 12)
		if (try_to_freeze())
			continue;
#endif
		set_current_state(TASK_INTERRUPTIBLE);
		schedule_timeout(15*HZ);
		read_lock(&GlobalSMBSeslock);
		/* check if any stuck requests that need
		   to be woken up and wakeq so the
		   thread can wake up and error out */
		list_for_each(tmp, &GlobalSMBSessionList) {
			ses = list_entry(tmp, struct cifsSesInfo,
				cifsSessionList);
			if (ses && ses->server &&
			     atomic_read(&ses->server->inFlight))
				wake_up_all(&ses->server->response_q);
		}
		read_unlock(&GlobalSMBSeslock);
	} while (!kthread_should_stop());

	return 0;
}

static int __init
init_cifs(void)
{
	int rc = 0;
#ifdef CONFIG_PROC_FS
	cifs_proc_init();
#endif
/*	INIT_LIST_HEAD(&GlobalServerList);*/	/* BB not implemented yet */
	INIT_LIST_HEAD(&GlobalSMBSessionList);
	INIT_LIST_HEAD(&GlobalTreeConnectionList);
	INIT_LIST_HEAD(&GlobalOplock_Q);
#ifdef CONFIG_CIFS_EXPERIMENTAL
	INIT_LIST_HEAD(&GlobalDnotifyReqList);
	INIT_LIST_HEAD(&GlobalDnotifyRsp_Q);
#endif
/*
 *  Initialize Global counters
 */
	atomic_set(&sesInfoAllocCount, 0);
	atomic_set(&tconInfoAllocCount, 0);
	atomic_set(&tcpSesAllocCount, 0);
	atomic_set(&tcpSesReconnectCount, 0);
	atomic_set(&tconInfoReconnectCount, 0);

	atomic_set(&bufAllocCount, 0);
	atomic_set(&smBufAllocCount, 0);
#ifdef CONFIG_CIFS_STATS2
	atomic_set(&totBufAllocCount, 0);
	atomic_set(&totSmBufAllocCount, 0);
#endif /* CONFIG_CIFS_STATS2 */

	atomic_set(&midCount, 0);
	GlobalCurrentXid = 0;
	GlobalTotalActiveXid = 0;
	GlobalMaxActiveXid = 0;
	memset(Local_System_Name, 0, 15);
	rwlock_init(&GlobalSMBSeslock);
	spin_lock_init(&GlobalMid_Lock);

	if (cifs_max_pending < 2) {
		cifs_max_pending = 2;
		cFYI(1, ("cifs_max_pending set to min of 2"));
	} else if (cifs_max_pending > 256) {
		cifs_max_pending = 256;
		cFYI(1, ("cifs_max_pending set to max of 256"));
	}

	rc = cifs_init_inodecache();
	if (rc)
		goto out_clean_proc;

	rc = cifs_init_mids();
	if (rc)
		goto out_destroy_inodecache;

	rc = cifs_init_request_bufs();
	if (rc)
		goto out_destroy_mids;

	rc = register_filesystem(&cifs_fs_type);
	if (rc)
		goto out_destroy_request_bufs;

	oplockThread = kthread_run(cifs_oplock_thread, NULL, "cifsoplockd");
	if (IS_ERR(oplockThread)) {
		rc = PTR_ERR(oplockThread);
		cERROR(1, ("error %d create oplock thread", rc));
		goto out_unregister_filesystem;
	}

	dnotifyThread = kthread_run(cifs_dnotify_thread, NULL, "cifsdnotifyd");
	if (IS_ERR(dnotifyThread)) {
		rc = PTR_ERR(dnotifyThread);
		cERROR(1, ("error %d create dnotify thread", rc));
		goto out_stop_oplock_thread;
	}

	return 0;

 out_stop_oplock_thread:
	kthread_stop(oplockThread);
 out_unregister_filesystem:
	unregister_filesystem(&cifs_fs_type);
 out_destroy_request_bufs:
	cifs_destroy_request_bufs();
 out_destroy_mids:
	cifs_destroy_mids();
 out_destroy_inodecache:
	cifs_destroy_inodecache();
 out_clean_proc:
#ifdef CONFIG_PROC_FS
	cifs_proc_clean();
#endif
	return rc;
}

static void __exit
exit_cifs(void)
{
	cFYI(0, ("exit_cifs"));
#ifdef CONFIG_PROC_FS
	cifs_proc_clean();
#endif
	unregister_filesystem(&cifs_fs_type);
	cifs_destroy_inodecache();
	cifs_destroy_mids();
	cifs_destroy_request_bufs();
	kthread_stop(oplockThread);
	kthread_stop(dnotifyThread);
}

MODULE_AUTHOR("Steve French <[e-mail]>");
MODULE_LICENSE("GPL");	/* combination of LGPL + GPL source behaves as GPL */
MODULE_DESCRIPTION
    ("VFS to access servers complying with the SNIA CIFS Specification "
     "e.g. Samba and Windows");
MODULE_VERSION(CIFS_VERSION);
module_init(init_cifs)
module_exit(exit_cifs)