blob: 34f80fa6fed16d379733e3db018f765831e09778 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Network block device - make block devices work over TCP
3 *
4 * Note that you can not swap over this thing, yet. Seems to work but
5 * deadlocks sometimes - you can not swap over TCP in general.
6 *
7 * Copyright 1997-2000 Pavel Machek <pavel@ucw.cz>
8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
9 *
Pavel Machekdbf492d2006-06-25 05:47:42 -070010 * This file is released under GPLv2 or later.
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 *
Pavel Machekdbf492d2006-06-25 05:47:42 -070012 * (part of code stolen from loop.c)
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 */
14
15#include <linux/major.h>
16
17#include <linux/blkdev.h>
18#include <linux/module.h>
19#include <linux/init.h>
20#include <linux/sched.h>
21#include <linux/fs.h>
22#include <linux/bio.h>
23#include <linux/stat.h>
24#include <linux/errno.h>
25#include <linux/file.h>
26#include <linux/ioctl.h>
Herbert Xu4b2f0262006-01-06 00:09:47 -080027#include <linux/compiler.h>
28#include <linux/err.h>
29#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <net/sock.h>
Trond Myklebust91cf45f2007-11-12 18:10:39 -080031#include <linux/net.h>
Laurent Vivier48cf6062008-04-29 01:02:46 -070032#include <linux/kthread.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <asm/uaccess.h>
Herbert Xu4b2f0262006-01-06 00:09:47 -080035#include <asm/system.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include <asm/types.h>
37
38#include <linux/nbd.h>
39
40#define LO_MAGIC 0x68797548
41
42#ifdef NDEBUG
43#define dprintk(flags, fmt...)
44#else /* NDEBUG */
45#define dprintk(flags, fmt...) do { \
46 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \
47} while (0)
48#define DBG_IOCTL 0x0004
49#define DBG_INIT 0x0010
50#define DBG_EXIT 0x0020
51#define DBG_BLKDEV 0x0100
52#define DBG_RX 0x0200
53#define DBG_TX 0x0400
54static unsigned int debugflags;
55#endif /* NDEBUG */
56
Ingo van Lil9c7a4162006-07-01 04:36:36 -070057static unsigned int nbds_max = 16;
Paul Clements20a81432008-02-08 04:21:51 -080058static struct nbd_device *nbd_dev;
Laurent Vivierd71a6d72008-04-29 01:02:51 -070059static int max_part;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
61/*
62 * Use just one lock (or at most 1 per NIC). Two arguments for this:
63 * 1. Each NIC is essentially a synchronization point for all servers
64 * accessed through that NIC so there's no need to have more locks
65 * than NICs anyway.
66 * 2. More locks lead to more "Dirty cache line bouncing" which will slow
67 * down each lock to the point where they're actually slower than just
68 * a single lock.
69 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this!
70 */
71static DEFINE_SPINLOCK(nbd_lock);
72
73#ifndef NDEBUG
74static const char *ioctl_cmd_to_ascii(int cmd)
75{
76 switch (cmd) {
77 case NBD_SET_SOCK: return "set-sock";
78 case NBD_SET_BLKSIZE: return "set-blksize";
79 case NBD_SET_SIZE: return "set-size";
80 case NBD_DO_IT: return "do-it";
81 case NBD_CLEAR_SOCK: return "clear-sock";
82 case NBD_CLEAR_QUE: return "clear-que";
83 case NBD_PRINT_DEBUG: return "print-debug";
84 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks";
85 case NBD_DISCONNECT: return "disconnect";
86 case BLKROSET: return "set-read-only";
87 case BLKFLSBUF: return "flush-buffer-cache";
88 }
89 return "unknown";
90}
91
92static const char *nbdcmd_to_ascii(int cmd)
93{
94 switch (cmd) {
95 case NBD_CMD_READ: return "read";
96 case NBD_CMD_WRITE: return "write";
97 case NBD_CMD_DISC: return "disconnect";
98 }
99 return "invalid";
100}
101#endif /* NDEBUG */
102
103static void nbd_end_request(struct request *req)
104{
Kiyoshi Ueda097c94a2007-12-11 17:44:06 -0500105 int error = req->errors ? -EIO : 0;
Jens Axboe165125e2007-07-24 09:28:11 +0200106 struct request_queue *q = req->q;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 unsigned long flags;
108
109 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
Kiyoshi Ueda097c94a2007-12-11 17:44:06 -0500110 req, error ? "failed" : "done");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
112 spin_lock_irqsave(q->queue_lock, flags);
Kiyoshi Ueda097c94a2007-12-11 17:44:06 -0500113 __blk_end_request(req, error, req->nr_sectors << 9);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 spin_unlock_irqrestore(q->queue_lock, flags);
115}
116
Paul Clements7fdfd402007-10-16 23:27:37 -0700117static void sock_shutdown(struct nbd_device *lo, int lock)
118{
119 /* Forcibly shutdown the socket causing all listeners
120 * to error
121 *
122 * FIXME: This code is duplicated from sys_shutdown, but
123 * there should be a more generic interface rather than
124 * calling socket ops directly here */
125 if (lock)
126 mutex_lock(&lo->tx_lock);
127 if (lo->sock) {
128 printk(KERN_WARNING "%s: shutting down socket\n",
129 lo->disk->disk_name);
Trond Myklebust91cf45f2007-11-12 18:10:39 -0800130 kernel_sock_shutdown(lo->sock, SHUT_RDWR);
Paul Clements7fdfd402007-10-16 23:27:37 -0700131 lo->sock = NULL;
132 }
133 if (lock)
134 mutex_unlock(&lo->tx_lock);
135}
136
137static void nbd_xmit_timeout(unsigned long arg)
138{
139 struct task_struct *task = (struct task_struct *)arg;
140
141 printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n",
142 task->comm, task->pid);
143 force_sig(SIGKILL, task);
144}
145
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146/*
147 * Send or receive packet.
148 */
Paul Clements7fdfd402007-10-16 23:27:37 -0700149static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 int msg_flags)
151{
Paul Clements7fdfd402007-10-16 23:27:37 -0700152 struct socket *sock = lo->sock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 int result;
154 struct msghdr msg;
155 struct kvec iov;
Oleg Nesterovbe0ef952007-07-15 23:41:32 -0700156 sigset_t blocked, oldset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
Mike Snitzerffc41cf2008-04-02 13:04:47 -0700158 if (unlikely(!sock)) {
159 printk(KERN_ERR "%s: Attempted %s on closed socket in sock_xmit\n",
160 lo->disk->disk_name, (send ? "send" : "recv"));
161 return -EINVAL;
162 }
163
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 /* Allow interception of SIGKILL only
165 * Don't allow other signals to interrupt the transmission */
Oleg Nesterovbe0ef952007-07-15 23:41:32 -0700166 siginitsetinv(&blocked, sigmask(SIGKILL));
167 sigprocmask(SIG_SETMASK, &blocked, &oldset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
169 do {
170 sock->sk->sk_allocation = GFP_NOIO;
171 iov.iov_base = buf;
172 iov.iov_len = size;
173 msg.msg_name = NULL;
174 msg.msg_namelen = 0;
175 msg.msg_control = NULL;
176 msg.msg_controllen = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
178
Paul Clements7fdfd402007-10-16 23:27:37 -0700179 if (send) {
180 struct timer_list ti;
181
182 if (lo->xmit_timeout) {
183 init_timer(&ti);
184 ti.function = nbd_xmit_timeout;
185 ti.data = (unsigned long)current;
186 ti.expires = jiffies + lo->xmit_timeout;
187 add_timer(&ti);
188 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 result = kernel_sendmsg(sock, &msg, &iov, 1, size);
Paul Clements7fdfd402007-10-16 23:27:37 -0700190 if (lo->xmit_timeout)
191 del_timer_sync(&ti);
192 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0);
194
195 if (signal_pending(current)) {
196 siginfo_t info;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -0700198 task_pid_nr(current), current->comm,
Oleg Nesterovbe0ef952007-07-15 23:41:32 -0700199 dequeue_signal_lock(current, &current->blocked, &info));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 result = -EINTR;
Paul Clements7fdfd402007-10-16 23:27:37 -0700201 sock_shutdown(lo, !send);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 break;
203 }
204
205 if (result <= 0) {
206 if (result == 0)
207 result = -EPIPE; /* short read */
208 break;
209 }
210 size -= result;
211 buf += result;
212 } while (size > 0);
213
Oleg Nesterovbe0ef952007-07-15 23:41:32 -0700214 sigprocmask(SIG_SETMASK, &oldset, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
216 return result;
217}
218
Paul Clements7fdfd402007-10-16 23:27:37 -0700219static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 int flags)
221{
222 int result;
223 void *kaddr = kmap(bvec->bv_page);
Paul Clements7fdfd402007-10-16 23:27:37 -0700224 result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 kunmap(bvec->bv_page);
226 return result;
227}
228
Paul Clements7fdfd402007-10-16 23:27:37 -0700229/* always call with the tx_lock held */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230static int nbd_send_req(struct nbd_device *lo, struct request *req)
231{
NeilBrown5705f702007-09-25 12:35:59 +0200232 int result, flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 struct nbd_request request;
234 unsigned long size = req->nr_sectors << 9;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
236 request.magic = htonl(NBD_REQUEST_MAGIC);
237 request.type = htonl(nbd_cmd(req));
238 request.from = cpu_to_be64((u64) req->sector << 9);
239 request.len = htonl(size);
240 memcpy(request.handle, &req, sizeof(req));
241
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n",
243 lo->disk->disk_name, req,
244 nbdcmd_to_ascii(nbd_cmd(req)),
245 (unsigned long long)req->sector << 9,
246 req->nr_sectors << 9);
Paul Clements7fdfd402007-10-16 23:27:37 -0700247 result = sock_xmit(lo, 1, &request, sizeof(request),
248 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 if (result <= 0) {
250 printk(KERN_ERR "%s: Send control failed (result %d)\n",
251 lo->disk->disk_name, result);
252 goto error_out;
253 }
254
255 if (nbd_cmd(req) == NBD_CMD_WRITE) {
NeilBrown5705f702007-09-25 12:35:59 +0200256 struct req_iterator iter;
257 struct bio_vec *bvec;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 /*
259 * we are really probing at internals to determine
260 * whether to set MSG_MORE or not...
261 */
NeilBrown5705f702007-09-25 12:35:59 +0200262 rq_for_each_segment(bvec, req, iter) {
Jens Axboe6c92e692007-08-16 13:43:12 +0200263 flags = 0;
264 if (!rq_iter_last(req, iter))
265 flags = MSG_MORE;
266 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
267 lo->disk->disk_name, req, bvec->bv_len);
Paul Clements7fdfd402007-10-16 23:27:37 -0700268 result = sock_send_bvec(lo, bvec, flags);
Jens Axboe6c92e692007-08-16 13:43:12 +0200269 if (result <= 0) {
270 printk(KERN_ERR "%s: Send data failed (result %d)\n",
271 lo->disk->disk_name, result);
272 goto error_out;
273 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 }
275 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 return 0;
277
278error_out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 return 1;
280}
281
Denis Cheng0cbc591b2007-10-16 23:26:14 -0700282static struct request *nbd_find_request(struct nbd_device *lo,
283 struct request *xreq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284{
Denis Chengd2c97402007-10-16 23:26:14 -0700285 struct request *req, *tmp;
Herbert Xu4b2f0262006-01-06 00:09:47 -0800286 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
Herbert Xu4b2f0262006-01-06 00:09:47 -0800288 err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq);
289 if (unlikely(err))
290 goto out;
291
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 spin_lock(&lo->queue_lock);
Denis Chengd2c97402007-10-16 23:26:14 -0700293 list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 if (req != xreq)
295 continue;
296 list_del_init(&req->queuelist);
297 spin_unlock(&lo->queue_lock);
298 return req;
299 }
300 spin_unlock(&lo->queue_lock);
Herbert Xu4b2f0262006-01-06 00:09:47 -0800301
302 err = -ENOENT;
303
304out:
305 return ERR_PTR(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306}
307
Paul Clements7fdfd402007-10-16 23:27:37 -0700308static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309{
310 int result;
311 void *kaddr = kmap(bvec->bv_page);
Paul Clements7fdfd402007-10-16 23:27:37 -0700312 result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 MSG_WAITALL);
314 kunmap(bvec->bv_page);
315 return result;
316}
317
318/* NULL returned = something went wrong, inform userspace */
319static struct request *nbd_read_stat(struct nbd_device *lo)
320{
321 int result;
322 struct nbd_reply reply;
323 struct request *req;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
325 reply.magic = 0;
Paul Clements7fdfd402007-10-16 23:27:37 -0700326 result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 if (result <= 0) {
328 printk(KERN_ERR "%s: Receive control failed (result %d)\n",
329 lo->disk->disk_name, result);
330 goto harderror;
331 }
Michal Feixe4b57e02006-07-30 03:03:31 -0700332
333 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
334 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n",
335 lo->disk->disk_name,
336 (unsigned long)ntohl(reply.magic));
337 result = -EPROTO;
338 goto harderror;
339 }
340
Denis Cheng0cbc591b2007-10-16 23:26:14 -0700341 req = nbd_find_request(lo, *(struct request **)reply.handle);
Hirofumi Nakagawa801678c2008-04-29 01:03:09 -0700342 if (IS_ERR(req)) {
Herbert Xu4b2f0262006-01-06 00:09:47 -0800343 result = PTR_ERR(req);
344 if (result != -ENOENT)
345 goto harderror;
346
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 printk(KERN_ERR "%s: Unexpected reply (%p)\n",
348 lo->disk->disk_name, reply.handle);
349 result = -EBADR;
350 goto harderror;
351 }
352
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 if (ntohl(reply.error)) {
354 printk(KERN_ERR "%s: Other side returned error (%d)\n",
355 lo->disk->disk_name, ntohl(reply.error));
356 req->errors++;
357 return req;
358 }
359
360 dprintk(DBG_RX, "%s: request %p: got reply\n",
361 lo->disk->disk_name, req);
362 if (nbd_cmd(req) == NBD_CMD_READ) {
NeilBrown5705f702007-09-25 12:35:59 +0200363 struct req_iterator iter;
364 struct bio_vec *bvec;
365
366 rq_for_each_segment(bvec, req, iter) {
Paul Clements7fdfd402007-10-16 23:27:37 -0700367 result = sock_recv_bvec(lo, bvec);
Jens Axboe6c92e692007-08-16 13:43:12 +0200368 if (result <= 0) {
369 printk(KERN_ERR "%s: Receive data failed (result %d)\n",
370 lo->disk->disk_name, result);
371 req->errors++;
372 return req;
373 }
374 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
375 lo->disk->disk_name, req, bvec->bv_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 }
377 }
378 return req;
379harderror:
380 lo->harderror = result;
381 return NULL;
382}
383
Kay Sieversedfaa7c2007-05-21 22:08:01 +0200384static ssize_t pid_show(struct device *dev,
385 struct device_attribute *attr, char *buf)
Paul Clements6b39bb62006-12-06 20:40:53 -0800386{
Kay Sieversedfaa7c2007-05-21 22:08:01 +0200387 struct gendisk *disk = dev_to_disk(dev);
388
389 return sprintf(buf, "%ld\n",
Paul Clements6b39bb62006-12-06 20:40:53 -0800390 (long) ((struct nbd_device *)disk->private_data)->pid);
391}
392
Kay Sieversedfaa7c2007-05-21 22:08:01 +0200393static struct device_attribute pid_attr = {
Parag Warudkar01e8ef12008-10-18 20:28:50 -0700394 .attr = { .name = "pid", .mode = S_IRUGO},
Paul Clements6b39bb62006-12-06 20:40:53 -0800395 .show = pid_show,
396};
397
WANG Cong84963042007-05-09 02:33:36 -0700398static int nbd_do_it(struct nbd_device *lo)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399{
400 struct request *req;
WANG Cong84963042007-05-09 02:33:36 -0700401 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402
403 BUG_ON(lo->magic != LO_MAGIC);
404
Paul Clements6b39bb62006-12-06 20:40:53 -0800405 lo->pid = current->pid;
Tejun Heoed9e1982008-08-25 19:56:05 +0900406 ret = sysfs_create_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr);
WANG Cong84963042007-05-09 02:33:36 -0700407 if (ret) {
408 printk(KERN_ERR "nbd: sysfs_create_file failed!");
Pavel Machekc91192d2009-01-15 13:51:03 -0800409 lo->pid = 0;
WANG Cong84963042007-05-09 02:33:36 -0700410 return ret;
411 }
Paul Clements6b39bb62006-12-06 20:40:53 -0800412
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 while ((req = nbd_read_stat(lo)) != NULL)
414 nbd_end_request(req);
Paul Clements6b39bb62006-12-06 20:40:53 -0800415
Tejun Heoed9e1982008-08-25 19:56:05 +0900416 sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr);
Pavel Machekc91192d2009-01-15 13:51:03 -0800417 lo->pid = 0;
WANG Cong84963042007-05-09 02:33:36 -0700418 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419}
420
421static void nbd_clear_que(struct nbd_device *lo)
422{
423 struct request *req;
424
425 BUG_ON(lo->magic != LO_MAGIC);
426
Herbert Xu4b2f0262006-01-06 00:09:47 -0800427 /*
428 * Because we have set lo->sock to NULL under the tx_lock, all
429 * modifications to the list must have completed by now. For
430 * the same reason, the active_req must be NULL.
431 *
432 * As a consequence, we don't need to take the spin lock while
433 * purging the list here.
434 */
435 BUG_ON(lo->sock);
436 BUG_ON(lo->active_req);
437
438 while (!list_empty(&lo->queue_head)) {
439 req = list_entry(lo->queue_head.next, struct request,
440 queuelist);
441 list_del_init(&req->queuelist);
442 req->errors++;
443 nbd_end_request(req);
444 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445}
446
Paul Clements7fdfd402007-10-16 23:27:37 -0700447
Laurent Vivier48cf6062008-04-29 01:02:46 -0700448static void nbd_handle_req(struct nbd_device *lo, struct request *req)
449{
450 if (!blk_fs_request(req))
451 goto error_out;
452
453 nbd_cmd(req) = NBD_CMD_READ;
454 if (rq_data_dir(req) == WRITE) {
455 nbd_cmd(req) = NBD_CMD_WRITE;
456 if (lo->flags & NBD_READ_ONLY) {
457 printk(KERN_ERR "%s: Write on read-only\n",
458 lo->disk->disk_name);
459 goto error_out;
460 }
461 }
462
463 req->errors = 0;
464
465 mutex_lock(&lo->tx_lock);
466 if (unlikely(!lo->sock)) {
467 mutex_unlock(&lo->tx_lock);
468 printk(KERN_ERR "%s: Attempted send on closed socket\n",
469 lo->disk->disk_name);
470 req->errors++;
471 nbd_end_request(req);
472 return;
473 }
474
475 lo->active_req = req;
476
477 if (nbd_send_req(lo, req) != 0) {
478 printk(KERN_ERR "%s: Request send failed\n",
479 lo->disk->disk_name);
480 req->errors++;
481 nbd_end_request(req);
482 } else {
483 spin_lock(&lo->queue_lock);
484 list_add(&req->queuelist, &lo->queue_head);
485 spin_unlock(&lo->queue_lock);
486 }
487
488 lo->active_req = NULL;
489 mutex_unlock(&lo->tx_lock);
490 wake_up_all(&lo->active_wq);
491
492 return;
493
494error_out:
495 req->errors++;
496 nbd_end_request(req);
497}
498
499static int nbd_thread(void *data)
500{
501 struct nbd_device *lo = data;
502 struct request *req;
503
504 set_user_nice(current, -20);
505 while (!kthread_should_stop() || !list_empty(&lo->waiting_queue)) {
506 /* wait for something to do */
507 wait_event_interruptible(lo->waiting_wq,
508 kthread_should_stop() ||
509 !list_empty(&lo->waiting_queue));
510
511 /* extract request */
512 if (list_empty(&lo->waiting_queue))
513 continue;
514
515 spin_lock_irq(&lo->queue_lock);
516 req = list_entry(lo->waiting_queue.next, struct request,
517 queuelist);
518 list_del_init(&req->queuelist);
519 spin_unlock_irq(&lo->queue_lock);
520
521 /* handle request */
522 nbd_handle_req(lo, req);
523 }
524 return 0;
525}
526
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527/*
528 * We always wait for result of write, for now. It would be nice to make it optional
529 * in future
Boaz Harroshe654bc42007-06-20 13:53:23 +0200530 * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); }
532 */
533
Jens Axboe165125e2007-07-24 09:28:11 +0200534static void do_nbd_request(struct request_queue * q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535{
536 struct request *req;
537
538 while ((req = elv_next_request(q)) != NULL) {
539 struct nbd_device *lo;
540
541 blkdev_dequeue_request(req);
Laurent Vivier48cf6062008-04-29 01:02:46 -0700542
543 spin_unlock_irq(q->queue_lock);
544
Jens Axboe4aff5e22006-08-10 08:44:47 +0200545 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n",
546 req->rq_disk->disk_name, req, req->cmd_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 lo = req->rq_disk->private_data;
549
550 BUG_ON(lo->magic != LO_MAGIC);
551
Laurent Vivier48cf6062008-04-29 01:02:46 -0700552 spin_lock_irq(&lo->queue_lock);
553 list_add_tail(&req->queuelist, &lo->waiting_queue);
554 spin_unlock_irq(&lo->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555
Laurent Vivier48cf6062008-04-29 01:02:46 -0700556 wake_up(&lo->waiting_wq);
Herbert Xu4b2f0262006-01-06 00:09:47 -0800557
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 spin_lock_irq(q->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560}
561
Al Viroa8cdc302008-03-02 09:33:33 -0500562static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 unsigned int cmd, unsigned long arg)
564{
Al Viroa8cdc302008-03-02 09:33:33 -0500565 struct nbd_device *lo = bdev->bd_disk->private_data;
566 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 int error;
568 struct request sreq ;
Laurent Vivier48cf6062008-04-29 01:02:46 -0700569 struct task_struct *thread;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570
571 if (!capable(CAP_SYS_ADMIN))
572 return -EPERM;
573
574 BUG_ON(lo->magic != LO_MAGIC);
575
576 /* Anyone capable of this syscall can do *real bad* things */
577 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
578 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
579
580 switch (cmd) {
581 case NBD_DISCONNECT:
582 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name);
FUJITA Tomonori4f54eec2008-04-29 09:54:37 +0200583 blk_rq_init(NULL, &sreq);
Jens Axboe4aff5e22006-08-10 08:44:47 +0200584 sreq.cmd_type = REQ_TYPE_SPECIAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 nbd_cmd(&sreq) = NBD_CMD_DISC;
586 /*
587 * Set these to sane values in case server implementation
588 * fails to check the request type first and also to keep
589 * debugging output cleaner.
590 */
591 sreq.sector = 0;
592 sreq.nr_sectors = 0;
593 if (!lo->sock)
594 return -EINVAL;
Paul Clements7fdfd402007-10-16 23:27:37 -0700595 mutex_lock(&lo->tx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 nbd_send_req(lo, &sreq);
Paul Clements7fdfd402007-10-16 23:27:37 -0700597 mutex_unlock(&lo->tx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 return 0;
599
600 case NBD_CLEAR_SOCK:
601 error = 0;
Ingo Molnar82d4dc52006-03-23 03:00:38 -0800602 mutex_lock(&lo->tx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 lo->sock = NULL;
Ingo Molnar82d4dc52006-03-23 03:00:38 -0800604 mutex_unlock(&lo->tx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 file = lo->file;
606 lo->file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 nbd_clear_que(lo);
Herbert Xu4b2f0262006-01-06 00:09:47 -0800608 BUG_ON(!list_empty(&lo->queue_head));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 if (file)
610 fput(file);
611 return error;
612 case NBD_SET_SOCK:
613 if (lo->file)
614 return -EBUSY;
615 error = -EINVAL;
616 file = fget(arg);
617 if (file) {
Al Viroa8cdc302008-03-02 09:33:33 -0500618 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 if (S_ISSOCK(inode->i_mode)) {
620 lo->file = file;
621 lo->sock = SOCKET_I(inode);
Laurent Vivierd71a6d72008-04-29 01:02:51 -0700622 if (max_part > 0)
623 bdev->bd_invalidated = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 error = 0;
625 } else {
626 fput(file);
627 }
628 }
629 return error;
630 case NBD_SET_BLKSIZE:
631 lo->blksize = arg;
632 lo->bytesize &= ~(lo->blksize-1);
Al Viroa8cdc302008-03-02 09:33:33 -0500633 bdev->bd_inode->i_size = lo->bytesize;
634 set_blocksize(bdev, lo->blksize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 set_capacity(lo->disk, lo->bytesize >> 9);
636 return 0;
637 case NBD_SET_SIZE:
638 lo->bytesize = arg & ~(lo->blksize-1);
Al Viroa8cdc302008-03-02 09:33:33 -0500639 bdev->bd_inode->i_size = lo->bytesize;
640 set_blocksize(bdev, lo->blksize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 set_capacity(lo->disk, lo->bytesize >> 9);
642 return 0;
Paul Clements7fdfd402007-10-16 23:27:37 -0700643 case NBD_SET_TIMEOUT:
644 lo->xmit_timeout = arg * HZ;
645 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 case NBD_SET_SIZE_BLOCKS:
647 lo->bytesize = ((u64) arg) * lo->blksize;
Al Viroa8cdc302008-03-02 09:33:33 -0500648 bdev->bd_inode->i_size = lo->bytesize;
649 set_blocksize(bdev, lo->blksize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 set_capacity(lo->disk, lo->bytesize >> 9);
651 return 0;
652 case NBD_DO_IT:
Pavel Machekc91192d2009-01-15 13:51:03 -0800653 if (lo->pid)
654 return -EBUSY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 if (!lo->file)
656 return -EINVAL;
Laurent Vivier48cf6062008-04-29 01:02:46 -0700657 thread = kthread_create(nbd_thread, lo, lo->disk->disk_name);
658 if (IS_ERR(thread))
659 return PTR_ERR(thread);
660 wake_up_process(thread);
WANG Cong84963042007-05-09 02:33:36 -0700661 error = nbd_do_it(lo);
Laurent Vivier48cf6062008-04-29 01:02:46 -0700662 kthread_stop(thread);
WANG Cong84963042007-05-09 02:33:36 -0700663 if (error)
664 return error;
Paul Clements7fdfd402007-10-16 23:27:37 -0700665 sock_shutdown(lo, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 file = lo->file;
667 lo->file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 nbd_clear_que(lo);
669 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name);
670 if (file)
671 fput(file);
Paul Clements4b86a872007-10-16 23:27:36 -0700672 lo->bytesize = 0;
Al Viroa8cdc302008-03-02 09:33:33 -0500673 bdev->bd_inode->i_size = 0;
Paul Clements4b86a872007-10-16 23:27:36 -0700674 set_capacity(lo->disk, 0);
Laurent Vivierd71a6d72008-04-29 01:02:51 -0700675 if (max_part > 0)
Al Viroa8cdc302008-03-02 09:33:33 -0500676 ioctl_by_bdev(bdev, BLKRRPART, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 return lo->harderror;
678 case NBD_CLEAR_QUE:
Herbert Xu4b2f0262006-01-06 00:09:47 -0800679 /*
680 * This is for compatibility only. The queue is always cleared
681 * by NBD_DO_IT or NBD_CLEAR_SOCK.
682 */
683 BUG_ON(!lo->sock && !list_empty(&lo->queue_head));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 return 0;
685 case NBD_PRINT_DEBUG:
686 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n",
Al Viroa8cdc302008-03-02 09:33:33 -0500687 bdev->bd_disk->disk_name,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 lo->queue_head.next, lo->queue_head.prev,
689 &lo->queue_head);
690 return 0;
691 }
692 return -EINVAL;
693}
694
695static struct block_device_operations nbd_fops =
696{
697 .owner = THIS_MODULE,
Al Viroa8cdc302008-03-02 09:33:33 -0500698 .locked_ioctl = nbd_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699};
700
701/*
702 * And here should be modules and kernel interface
703 * (Just smiley confuses emacs :-)
704 */
705
706static int __init nbd_init(void)
707{
708 int err = -ENOMEM;
709 int i;
Laurent Vivierd71a6d72008-04-29 01:02:51 -0700710 int part_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711
Adrian Bunk5b7b18c2006-03-25 03:07:04 -0800712 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713
Laurent Vivierd71a6d72008-04-29 01:02:51 -0700714 if (max_part < 0) {
715 printk(KERN_CRIT "nbd: max_part must be >= 0\n");
716 return -EINVAL;
717 }
718
Sven Wegenerf3944d62008-08-20 14:09:07 -0700719 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
720 if (!nbd_dev)
721 return -ENOMEM;
722
Laurent Vivierd71a6d72008-04-29 01:02:51 -0700723 part_shift = 0;
724 if (max_part > 0)
725 part_shift = fls(max_part);
726
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700727 for (i = 0; i < nbds_max; i++) {
Laurent Vivierd71a6d72008-04-29 01:02:51 -0700728 struct gendisk *disk = alloc_disk(1 << part_shift);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 if (!disk)
730 goto out;
731 nbd_dev[i].disk = disk;
732 /*
733 * The new linux 2.5 block layer implementation requires
734 * every gendisk to have its very own request_queue struct.
735 * These structs are big so we dynamically allocate them.
736 */
737 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock);
738 if (!disk->queue) {
739 put_disk(disk);
740 goto out;
741 }
Jens Axboe31dcfab2008-10-31 10:06:37 +0100742 /*
743 * Tell the block layer that we are not a rotational device
744 */
745 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 }
747
748 if (register_blkdev(NBD_MAJOR, "nbd")) {
749 err = -EIO;
750 goto out;
751 }
752
753 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
754 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
755
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700756 for (i = 0; i < nbds_max; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 struct gendisk *disk = nbd_dev[i].disk;
758 nbd_dev[i].file = NULL;
759 nbd_dev[i].magic = LO_MAGIC;
760 nbd_dev[i].flags = 0;
Laurent Vivier48cf6062008-04-29 01:02:46 -0700761 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 spin_lock_init(&nbd_dev[i].queue_lock);
763 INIT_LIST_HEAD(&nbd_dev[i].queue_head);
Ingo Molnar82d4dc52006-03-23 03:00:38 -0800764 mutex_init(&nbd_dev[i].tx_lock);
Herbert Xu4b2f0262006-01-06 00:09:47 -0800765 init_waitqueue_head(&nbd_dev[i].active_wq);
Laurent Vivier48cf6062008-04-29 01:02:46 -0700766 init_waitqueue_head(&nbd_dev[i].waiting_wq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 nbd_dev[i].blksize = 1024;
Paul Clements4b86a872007-10-16 23:27:36 -0700768 nbd_dev[i].bytesize = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 disk->major = NBD_MAJOR;
Laurent Vivierd71a6d72008-04-29 01:02:51 -0700770 disk->first_minor = i << part_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 disk->fops = &nbd_fops;
772 disk->private_data = &nbd_dev[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773 sprintf(disk->disk_name, "nbd%d", i);
Paul Clements4b86a872007-10-16 23:27:36 -0700774 set_capacity(disk, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 add_disk(disk);
776 }
777
778 return 0;
779out:
780 while (i--) {
781 blk_cleanup_queue(nbd_dev[i].disk->queue);
782 put_disk(nbd_dev[i].disk);
783 }
Sven Wegenerf3944d62008-08-20 14:09:07 -0700784 kfree(nbd_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 return err;
786}
787
788static void __exit nbd_cleanup(void)
789{
790 int i;
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700791 for (i = 0; i < nbds_max; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 struct gendisk *disk = nbd_dev[i].disk;
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700793 nbd_dev[i].magic = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 if (disk) {
795 del_gendisk(disk);
796 blk_cleanup_queue(disk->queue);
797 put_disk(disk);
798 }
799 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 unregister_blkdev(NBD_MAJOR, "nbd");
Sven Wegenerf3944d62008-08-20 14:09:07 -0700801 kfree(nbd_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
803}
804
805module_init(nbd_init);
806module_exit(nbd_cleanup);
807
808MODULE_DESCRIPTION("Network Block Device");
809MODULE_LICENSE("GPL");
810
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700811module_param(nbds_max, int, 0444);
Laurent Vivierd71a6d72008-04-29 01:02:51 -0700812MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
813module_param(max_part, int, 0444);
814MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815#ifndef NDEBUG
816module_param(debugflags, int, 0644);
817MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
818#endif