| 1 | /* |
| 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, 2008 Pavel Machek <pavel@ucw.cz> |
| 8 | * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com> |
| 9 | * |
| 10 | * This file is released under GPLv2 or later. |
| 11 | * |
| 12 | * (part of code stolen from loop.c) |
| 13 | */ |
| 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> |
| 27 | #include <linux/mutex.h> |
| 28 | #include <linux/compiler.h> |
| 29 | #include <linux/err.h> |
| 30 | #include <linux/kernel.h> |
| 31 | #include <linux/slab.h> |
| 32 | #include <net/sock.h> |
| 33 | #include <linux/net.h> |
| 34 | #include <linux/kthread.h> |
| 35 | |
| 36 | #include <asm/uaccess.h> |
| 37 | #include <asm/system.h> |
| 38 | #include <asm/types.h> |
| 39 | |
| 40 | #include <linux/nbd.h> |
| 41 | |
| 42 | #define LO_MAGIC 0x68797548 |
| 43 | |
| 44 | #ifdef NDEBUG |
| 45 | #define dprintk(flags, fmt...) |
| 46 | #else /* NDEBUG */ |
| 47 | #define dprintk(flags, fmt...) do { \ |
| 48 | if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ |
| 49 | } while (0) |
| 50 | #define DBG_IOCTL 0x0004 |
| 51 | #define DBG_INIT 0x0010 |
| 52 | #define DBG_EXIT 0x0020 |
| 53 | #define DBG_BLKDEV 0x0100 |
| 54 | #define DBG_RX 0x0200 |
| 55 | #define DBG_TX 0x0400 |
| 56 | static DEFINE_MUTEX(nbd_mutex); |
| 57 | static unsigned int debugflags; |
| 58 | #endif /* NDEBUG */ |
| 59 | |
| 60 | static unsigned int nbds_max = 16; |
| 61 | static struct nbd_device *nbd_dev; |
| 62 | static int max_part; |
| 63 | |
| 64 | /* |
| 65 | * Use just one lock (or at most 1 per NIC). Two arguments for this: |
| 66 | * 1. Each NIC is essentially a synchronization point for all servers |
| 67 | * accessed through that NIC so there's no need to have more locks |
| 68 | * than NICs anyway. |
| 69 | * 2. More locks lead to more "Dirty cache line bouncing" which will slow |
| 70 | * down each lock to the point where they're actually slower than just |
| 71 | * a single lock. |
| 72 | * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! |
| 73 | */ |
| 74 | static DEFINE_SPINLOCK(nbd_lock); |
| 75 | |
| 76 | #ifndef NDEBUG |
| 77 | static const char *ioctl_cmd_to_ascii(int cmd) |
| 78 | { |
| 79 | switch (cmd) { |
| 80 | case NBD_SET_SOCK: return "set-sock"; |
| 81 | case NBD_SET_BLKSIZE: return "set-blksize"; |
| 82 | case NBD_SET_SIZE: return "set-size"; |
| 83 | case NBD_DO_IT: return "do-it"; |
| 84 | case NBD_CLEAR_SOCK: return "clear-sock"; |
| 85 | case NBD_CLEAR_QUE: return "clear-que"; |
| 86 | case NBD_PRINT_DEBUG: return "print-debug"; |
| 87 | case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; |
| 88 | case NBD_DISCONNECT: return "disconnect"; |
| 89 | case BLKROSET: return "set-read-only"; |
| 90 | case BLKFLSBUF: return "flush-buffer-cache"; |
| 91 | } |
| 92 | return "unknown"; |
| 93 | } |
| 94 | |
| 95 | static const char *nbdcmd_to_ascii(int cmd) |
| 96 | { |
| 97 | switch (cmd) { |
| 98 | case NBD_CMD_READ: return "read"; |
| 99 | case NBD_CMD_WRITE: return "write"; |
| 100 | case NBD_CMD_DISC: return "disconnect"; |
| 101 | } |
| 102 | return "invalid"; |
| 103 | } |
| 104 | #endif /* NDEBUG */ |
| 105 | |
| 106 | static void nbd_end_request(struct request *req) |
| 107 | { |
| 108 | int error = req->errors ? -EIO : 0; |
| 109 | struct request_queue *q = req->q; |
| 110 | unsigned long flags; |
| 111 | |
| 112 | dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, |
| 113 | req, error ? "failed" : "done"); |
| 114 | |
| 115 | spin_lock_irqsave(q->queue_lock, flags); |
| 116 | __blk_end_request_all(req, error); |
| 117 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 118 | } |
| 119 | |
| 120 | static void sock_shutdown(struct nbd_device *lo, int lock) |
| 121 | { |
| 122 | /* Forcibly shutdown the socket causing all listeners |
| 123 | * to error |
| 124 | * |
| 125 | * FIXME: This code is duplicated from sys_shutdown, but |
| 126 | * there should be a more generic interface rather than |
| 127 | * calling socket ops directly here */ |
| 128 | if (lock) |
| 129 | mutex_lock(&lo->tx_lock); |
| 130 | if (lo->sock) { |
| 131 | printk(KERN_WARNING "%s: shutting down socket\n", |
| 132 | lo->disk->disk_name); |
| 133 | kernel_sock_shutdown(lo->sock, SHUT_RDWR); |
| 134 | lo->sock = NULL; |
| 135 | } |
| 136 | if (lock) |
| 137 | mutex_unlock(&lo->tx_lock); |
| 138 | } |
| 139 | |
| 140 | static void nbd_xmit_timeout(unsigned long arg) |
| 141 | { |
| 142 | struct task_struct *task = (struct task_struct *)arg; |
| 143 | |
| 144 | printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", |
| 145 | task->comm, task->pid); |
| 146 | force_sig(SIGKILL, task); |
| 147 | } |
| 148 | |
| 149 | /* |
| 150 | * Send or receive packet. |
| 151 | */ |
| 152 | static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size, |
| 153 | int msg_flags) |
| 154 | { |
| 155 | struct socket *sock = lo->sock; |
| 156 | int result; |
| 157 | struct msghdr msg; |
| 158 | struct kvec iov; |
| 159 | sigset_t blocked, oldset; |
| 160 | |
| 161 | if (unlikely(!sock)) { |
| 162 | printk(KERN_ERR "%s: Attempted %s on closed socket in sock_xmit\n", |
| 163 | lo->disk->disk_name, (send ? "send" : "recv")); |
| 164 | return -EINVAL; |
| 165 | } |
| 166 | |
| 167 | /* Allow interception of SIGKILL only |
| 168 | * Don't allow other signals to interrupt the transmission */ |
| 169 | siginitsetinv(&blocked, sigmask(SIGKILL)); |
| 170 | sigprocmask(SIG_SETMASK, &blocked, &oldset); |
| 171 | |
| 172 | do { |
| 173 | sock->sk->sk_allocation = GFP_NOIO; |
| 174 | iov.iov_base = buf; |
| 175 | iov.iov_len = size; |
| 176 | msg.msg_name = NULL; |
| 177 | msg.msg_namelen = 0; |
| 178 | msg.msg_control = NULL; |
| 179 | msg.msg_controllen = 0; |
| 180 | msg.msg_flags = msg_flags | MSG_NOSIGNAL; |
| 181 | |
| 182 | if (send) { |
| 183 | struct timer_list ti; |
| 184 | |
| 185 | if (lo->xmit_timeout) { |
| 186 | init_timer(&ti); |
| 187 | ti.function = nbd_xmit_timeout; |
| 188 | ti.data = (unsigned long)current; |
| 189 | ti.expires = jiffies + lo->xmit_timeout; |
| 190 | add_timer(&ti); |
| 191 | } |
| 192 | result = kernel_sendmsg(sock, &msg, &iov, 1, size); |
| 193 | if (lo->xmit_timeout) |
| 194 | del_timer_sync(&ti); |
| 195 | } else |
| 196 | result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0); |
| 197 | |
| 198 | if (signal_pending(current)) { |
| 199 | siginfo_t info; |
| 200 | printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", |
| 201 | task_pid_nr(current), current->comm, |
| 202 | dequeue_signal_lock(current, ¤t->blocked, &info)); |
| 203 | result = -EINTR; |
| 204 | sock_shutdown(lo, !send); |
| 205 | break; |
| 206 | } |
| 207 | |
| 208 | if (result <= 0) { |
| 209 | if (result == 0) |
| 210 | result = -EPIPE; /* short read */ |
| 211 | break; |
| 212 | } |
| 213 | size -= result; |
| 214 | buf += result; |
| 215 | } while (size > 0); |
| 216 | |
| 217 | sigprocmask(SIG_SETMASK, &oldset, NULL); |
| 218 | |
| 219 | return result; |
| 220 | } |
| 221 | |
| 222 | static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec, |
| 223 | int flags) |
| 224 | { |
| 225 | int result; |
| 226 | void *kaddr = kmap(bvec->bv_page); |
| 227 | result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags); |
| 228 | kunmap(bvec->bv_page); |
| 229 | return result; |
| 230 | } |
| 231 | |
| 232 | /* always call with the tx_lock held */ |
| 233 | static int nbd_send_req(struct nbd_device *lo, struct request *req) |
| 234 | { |
| 235 | int result, flags; |
| 236 | struct nbd_request request; |
| 237 | unsigned long size = blk_rq_bytes(req); |
| 238 | |
| 239 | request.magic = htonl(NBD_REQUEST_MAGIC); |
| 240 | request.type = htonl(nbd_cmd(req)); |
| 241 | request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); |
| 242 | request.len = htonl(size); |
| 243 | memcpy(request.handle, &req, sizeof(req)); |
| 244 | |
| 245 | dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n", |
| 246 | lo->disk->disk_name, req, |
| 247 | nbdcmd_to_ascii(nbd_cmd(req)), |
| 248 | (unsigned long long)blk_rq_pos(req) << 9, |
| 249 | blk_rq_bytes(req)); |
| 250 | result = sock_xmit(lo, 1, &request, sizeof(request), |
| 251 | (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); |
| 252 | if (result <= 0) { |
| 253 | printk(KERN_ERR "%s: Send control failed (result %d)\n", |
| 254 | lo->disk->disk_name, result); |
| 255 | goto error_out; |
| 256 | } |
| 257 | |
| 258 | if (nbd_cmd(req) == NBD_CMD_WRITE) { |
| 259 | struct req_iterator iter; |
| 260 | struct bio_vec *bvec; |
| 261 | /* |
| 262 | * we are really probing at internals to determine |
| 263 | * whether to set MSG_MORE or not... |
| 264 | */ |
| 265 | rq_for_each_segment(bvec, req, iter) { |
| 266 | flags = 0; |
| 267 | if (!rq_iter_last(req, iter)) |
| 268 | flags = MSG_MORE; |
| 269 | dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", |
| 270 | lo->disk->disk_name, req, bvec->bv_len); |
| 271 | result = sock_send_bvec(lo, bvec, flags); |
| 272 | if (result <= 0) { |
| 273 | printk(KERN_ERR "%s: Send data failed (result %d)\n", |
| 274 | lo->disk->disk_name, result); |
| 275 | goto error_out; |
| 276 | } |
| 277 | } |
| 278 | } |
| 279 | return 0; |
| 280 | |
| 281 | error_out: |
| 282 | return -EIO; |
| 283 | } |
| 284 | |
| 285 | static struct request *nbd_find_request(struct nbd_device *lo, |
| 286 | struct request *xreq) |
| 287 | { |
| 288 | struct request *req, *tmp; |
| 289 | int err; |
| 290 | |
| 291 | err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq); |
| 292 | if (unlikely(err)) |
| 293 | goto out; |
| 294 | |
| 295 | spin_lock(&lo->queue_lock); |
| 296 | list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) { |
| 297 | if (req != xreq) |
| 298 | continue; |
| 299 | list_del_init(&req->queuelist); |
| 300 | spin_unlock(&lo->queue_lock); |
| 301 | return req; |
| 302 | } |
| 303 | spin_unlock(&lo->queue_lock); |
| 304 | |
| 305 | err = -ENOENT; |
| 306 | |
| 307 | out: |
| 308 | return ERR_PTR(err); |
| 309 | } |
| 310 | |
| 311 | static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec) |
| 312 | { |
| 313 | int result; |
| 314 | void *kaddr = kmap(bvec->bv_page); |
| 315 | result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len, |
| 316 | MSG_WAITALL); |
| 317 | kunmap(bvec->bv_page); |
| 318 | return result; |
| 319 | } |
| 320 | |
| 321 | /* NULL returned = something went wrong, inform userspace */ |
| 322 | static struct request *nbd_read_stat(struct nbd_device *lo) |
| 323 | { |
| 324 | int result; |
| 325 | struct nbd_reply reply; |
| 326 | struct request *req; |
| 327 | |
| 328 | reply.magic = 0; |
| 329 | result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL); |
| 330 | if (result <= 0) { |
| 331 | printk(KERN_ERR "%s: Receive control failed (result %d)\n", |
| 332 | lo->disk->disk_name, result); |
| 333 | goto harderror; |
| 334 | } |
| 335 | |
| 336 | if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { |
| 337 | printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", |
| 338 | lo->disk->disk_name, |
| 339 | (unsigned long)ntohl(reply.magic)); |
| 340 | result = -EPROTO; |
| 341 | goto harderror; |
| 342 | } |
| 343 | |
| 344 | req = nbd_find_request(lo, *(struct request **)reply.handle); |
| 345 | if (IS_ERR(req)) { |
| 346 | result = PTR_ERR(req); |
| 347 | if (result != -ENOENT) |
| 348 | goto harderror; |
| 349 | |
| 350 | printk(KERN_ERR "%s: Unexpected reply (%p)\n", |
| 351 | lo->disk->disk_name, reply.handle); |
| 352 | result = -EBADR; |
| 353 | goto harderror; |
| 354 | } |
| 355 | |
| 356 | if (ntohl(reply.error)) { |
| 357 | printk(KERN_ERR "%s: Other side returned error (%d)\n", |
| 358 | lo->disk->disk_name, ntohl(reply.error)); |
| 359 | req->errors++; |
| 360 | return req; |
| 361 | } |
| 362 | |
| 363 | dprintk(DBG_RX, "%s: request %p: got reply\n", |
| 364 | lo->disk->disk_name, req); |
| 365 | if (nbd_cmd(req) == NBD_CMD_READ) { |
| 366 | struct req_iterator iter; |
| 367 | struct bio_vec *bvec; |
| 368 | |
| 369 | rq_for_each_segment(bvec, req, iter) { |
| 370 | result = sock_recv_bvec(lo, bvec); |
| 371 | if (result <= 0) { |
| 372 | printk(KERN_ERR "%s: Receive data failed (result %d)\n", |
| 373 | lo->disk->disk_name, result); |
| 374 | req->errors++; |
| 375 | return req; |
| 376 | } |
| 377 | dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", |
| 378 | lo->disk->disk_name, req, bvec->bv_len); |
| 379 | } |
| 380 | } |
| 381 | return req; |
| 382 | harderror: |
| 383 | lo->harderror = result; |
| 384 | return NULL; |
| 385 | } |
| 386 | |
| 387 | static ssize_t pid_show(struct device *dev, |
| 388 | struct device_attribute *attr, char *buf) |
| 389 | { |
| 390 | struct gendisk *disk = dev_to_disk(dev); |
| 391 | |
| 392 | return sprintf(buf, "%ld\n", |
| 393 | (long) ((struct nbd_device *)disk->private_data)->pid); |
| 394 | } |
| 395 | |
| 396 | static struct device_attribute pid_attr = { |
| 397 | .attr = { .name = "pid", .mode = S_IRUGO}, |
| 398 | .show = pid_show, |
| 399 | }; |
| 400 | |
| 401 | static int nbd_do_it(struct nbd_device *lo) |
| 402 | { |
| 403 | struct request *req; |
| 404 | int ret; |
| 405 | |
| 406 | BUG_ON(lo->magic != LO_MAGIC); |
| 407 | |
| 408 | lo->pid = current->pid; |
| 409 | ret = sysfs_create_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); |
| 410 | if (ret) { |
| 411 | printk(KERN_ERR "nbd: sysfs_create_file failed!"); |
| 412 | lo->pid = 0; |
| 413 | return ret; |
| 414 | } |
| 415 | |
| 416 | while ((req = nbd_read_stat(lo)) != NULL) |
| 417 | nbd_end_request(req); |
| 418 | |
| 419 | sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); |
| 420 | lo->pid = 0; |
| 421 | return 0; |
| 422 | } |
| 423 | |
| 424 | static void nbd_clear_que(struct nbd_device *lo) |
| 425 | { |
| 426 | struct request *req; |
| 427 | |
| 428 | BUG_ON(lo->magic != LO_MAGIC); |
| 429 | |
| 430 | /* |
| 431 | * Because we have set lo->sock to NULL under the tx_lock, all |
| 432 | * modifications to the list must have completed by now. For |
| 433 | * the same reason, the active_req must be NULL. |
| 434 | * |
| 435 | * As a consequence, we don't need to take the spin lock while |
| 436 | * purging the list here. |
| 437 | */ |
| 438 | BUG_ON(lo->sock); |
| 439 | BUG_ON(lo->active_req); |
| 440 | |
| 441 | while (!list_empty(&lo->queue_head)) { |
| 442 | req = list_entry(lo->queue_head.next, struct request, |
| 443 | queuelist); |
| 444 | list_del_init(&req->queuelist); |
| 445 | req->errors++; |
| 446 | nbd_end_request(req); |
| 447 | } |
| 448 | } |
| 449 | |
| 450 | |
| 451 | static void nbd_handle_req(struct nbd_device *lo, struct request *req) |
| 452 | { |
| 453 | if (req->cmd_type != REQ_TYPE_FS) |
| 454 | goto error_out; |
| 455 | |
| 456 | nbd_cmd(req) = NBD_CMD_READ; |
| 457 | if (rq_data_dir(req) == WRITE) { |
| 458 | nbd_cmd(req) = NBD_CMD_WRITE; |
| 459 | if (lo->flags & NBD_READ_ONLY) { |
| 460 | printk(KERN_ERR "%s: Write on read-only\n", |
| 461 | lo->disk->disk_name); |
| 462 | goto error_out; |
| 463 | } |
| 464 | } |
| 465 | |
| 466 | req->errors = 0; |
| 467 | |
| 468 | mutex_lock(&lo->tx_lock); |
| 469 | if (unlikely(!lo->sock)) { |
| 470 | mutex_unlock(&lo->tx_lock); |
| 471 | printk(KERN_ERR "%s: Attempted send on closed socket\n", |
| 472 | lo->disk->disk_name); |
| 473 | goto error_out; |
| 474 | } |
| 475 | |
| 476 | lo->active_req = req; |
| 477 | |
| 478 | if (nbd_send_req(lo, req) != 0) { |
| 479 | printk(KERN_ERR "%s: Request send failed\n", |
| 480 | lo->disk->disk_name); |
| 481 | req->errors++; |
| 482 | nbd_end_request(req); |
| 483 | } else { |
| 484 | spin_lock(&lo->queue_lock); |
| 485 | list_add(&req->queuelist, &lo->queue_head); |
| 486 | spin_unlock(&lo->queue_lock); |
| 487 | } |
| 488 | |
| 489 | lo->active_req = NULL; |
| 490 | mutex_unlock(&lo->tx_lock); |
| 491 | wake_up_all(&lo->active_wq); |
| 492 | |
| 493 | return; |
| 494 | |
| 495 | error_out: |
| 496 | req->errors++; |
| 497 | nbd_end_request(req); |
| 498 | } |
| 499 | |
| 500 | static int nbd_thread(void *data) |
| 501 | { |
| 502 | struct nbd_device *lo = data; |
| 503 | struct request *req; |
| 504 | |
| 505 | set_user_nice(current, -20); |
| 506 | while (!kthread_should_stop() || !list_empty(&lo->waiting_queue)) { |
| 507 | /* wait for something to do */ |
| 508 | wait_event_interruptible(lo->waiting_wq, |
| 509 | kthread_should_stop() || |
| 510 | !list_empty(&lo->waiting_queue)); |
| 511 | |
| 512 | /* extract request */ |
| 513 | if (list_empty(&lo->waiting_queue)) |
| 514 | continue; |
| 515 | |
| 516 | spin_lock_irq(&lo->queue_lock); |
| 517 | req = list_entry(lo->waiting_queue.next, struct request, |
| 518 | queuelist); |
| 519 | list_del_init(&req->queuelist); |
| 520 | spin_unlock_irq(&lo->queue_lock); |
| 521 | |
| 522 | /* handle request */ |
| 523 | nbd_handle_req(lo, req); |
| 524 | } |
| 525 | return 0; |
| 526 | } |
| 527 | |
| 528 | /* |
| 529 | * We always wait for result of write, for now. It would be nice to make it optional |
| 530 | * in future |
| 531 | * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) |
| 532 | * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } |
| 533 | */ |
| 534 | |
| 535 | static void do_nbd_request(struct request_queue *q) |
| 536 | { |
| 537 | struct request *req; |
| 538 | |
| 539 | while ((req = blk_fetch_request(q)) != NULL) { |
| 540 | struct nbd_device *lo; |
| 541 | |
| 542 | spin_unlock_irq(q->queue_lock); |
| 543 | |
| 544 | dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", |
| 545 | req->rq_disk->disk_name, req, req->cmd_type); |
| 546 | |
| 547 | lo = req->rq_disk->private_data; |
| 548 | |
| 549 | BUG_ON(lo->magic != LO_MAGIC); |
| 550 | |
| 551 | if (unlikely(!lo->sock)) { |
| 552 | printk(KERN_ERR "%s: Attempted send on closed socket\n", |
| 553 | lo->disk->disk_name); |
| 554 | req->errors++; |
| 555 | nbd_end_request(req); |
| 556 | spin_lock_irq(q->queue_lock); |
| 557 | continue; |
| 558 | } |
| 559 | |
| 560 | spin_lock_irq(&lo->queue_lock); |
| 561 | list_add_tail(&req->queuelist, &lo->waiting_queue); |
| 562 | spin_unlock_irq(&lo->queue_lock); |
| 563 | |
| 564 | wake_up(&lo->waiting_wq); |
| 565 | |
| 566 | spin_lock_irq(q->queue_lock); |
| 567 | } |
| 568 | } |
| 569 | |
| 570 | /* Must be called with tx_lock held */ |
| 571 | |
| 572 | static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *lo, |
| 573 | unsigned int cmd, unsigned long arg) |
| 574 | { |
| 575 | switch (cmd) { |
| 576 | case NBD_DISCONNECT: { |
| 577 | struct request sreq; |
| 578 | |
| 579 | printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); |
| 580 | |
| 581 | blk_rq_init(NULL, &sreq); |
| 582 | sreq.cmd_type = REQ_TYPE_SPECIAL; |
| 583 | nbd_cmd(&sreq) = NBD_CMD_DISC; |
| 584 | if (!lo->sock) |
| 585 | return -EINVAL; |
| 586 | nbd_send_req(lo, &sreq); |
| 587 | return 0; |
| 588 | } |
| 589 | |
| 590 | case NBD_CLEAR_SOCK: { |
| 591 | struct file *file; |
| 592 | |
| 593 | lo->sock = NULL; |
| 594 | file = lo->file; |
| 595 | lo->file = NULL; |
| 596 | nbd_clear_que(lo); |
| 597 | BUG_ON(!list_empty(&lo->queue_head)); |
| 598 | if (file) |
| 599 | fput(file); |
| 600 | return 0; |
| 601 | } |
| 602 | |
| 603 | case NBD_SET_SOCK: { |
| 604 | struct file *file; |
| 605 | if (lo->file) |
| 606 | return -EBUSY; |
| 607 | file = fget(arg); |
| 608 | if (file) { |
| 609 | struct inode *inode = file->f_path.dentry->d_inode; |
| 610 | if (S_ISSOCK(inode->i_mode)) { |
| 611 | lo->file = file; |
| 612 | lo->sock = SOCKET_I(inode); |
| 613 | if (max_part > 0) |
| 614 | bdev->bd_invalidated = 1; |
| 615 | return 0; |
| 616 | } else { |
| 617 | fput(file); |
| 618 | } |
| 619 | } |
| 620 | return -EINVAL; |
| 621 | } |
| 622 | |
| 623 | case NBD_SET_BLKSIZE: |
| 624 | lo->blksize = arg; |
| 625 | lo->bytesize &= ~(lo->blksize-1); |
| 626 | bdev->bd_inode->i_size = lo->bytesize; |
| 627 | set_blocksize(bdev, lo->blksize); |
| 628 | set_capacity(lo->disk, lo->bytesize >> 9); |
| 629 | return 0; |
| 630 | |
| 631 | case NBD_SET_SIZE: |
| 632 | lo->bytesize = arg & ~(lo->blksize-1); |
| 633 | bdev->bd_inode->i_size = lo->bytesize; |
| 634 | set_blocksize(bdev, lo->blksize); |
| 635 | set_capacity(lo->disk, lo->bytesize >> 9); |
| 636 | return 0; |
| 637 | |
| 638 | case NBD_SET_TIMEOUT: |
| 639 | lo->xmit_timeout = arg * HZ; |
| 640 | return 0; |
| 641 | |
| 642 | case NBD_SET_SIZE_BLOCKS: |
| 643 | lo->bytesize = ((u64) arg) * lo->blksize; |
| 644 | bdev->bd_inode->i_size = lo->bytesize; |
| 645 | set_blocksize(bdev, lo->blksize); |
| 646 | set_capacity(lo->disk, lo->bytesize >> 9); |
| 647 | return 0; |
| 648 | |
| 649 | case NBD_DO_IT: { |
| 650 | struct task_struct *thread; |
| 651 | struct file *file; |
| 652 | int error; |
| 653 | |
| 654 | if (lo->pid) |
| 655 | return -EBUSY; |
| 656 | if (!lo->file) |
| 657 | return -EINVAL; |
| 658 | |
| 659 | mutex_unlock(&lo->tx_lock); |
| 660 | |
| 661 | thread = kthread_create(nbd_thread, lo, lo->disk->disk_name); |
| 662 | if (IS_ERR(thread)) { |
| 663 | mutex_lock(&lo->tx_lock); |
| 664 | return PTR_ERR(thread); |
| 665 | } |
| 666 | wake_up_process(thread); |
| 667 | error = nbd_do_it(lo); |
| 668 | kthread_stop(thread); |
| 669 | |
| 670 | mutex_lock(&lo->tx_lock); |
| 671 | if (error) |
| 672 | return error; |
| 673 | sock_shutdown(lo, 0); |
| 674 | file = lo->file; |
| 675 | lo->file = NULL; |
| 676 | nbd_clear_que(lo); |
| 677 | printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); |
| 678 | if (file) |
| 679 | fput(file); |
| 680 | lo->bytesize = 0; |
| 681 | bdev->bd_inode->i_size = 0; |
| 682 | set_capacity(lo->disk, 0); |
| 683 | if (max_part > 0) |
| 684 | ioctl_by_bdev(bdev, BLKRRPART, 0); |
| 685 | return lo->harderror; |
| 686 | } |
| 687 | |
| 688 | case NBD_CLEAR_QUE: |
| 689 | /* |
| 690 | * This is for compatibility only. The queue is always cleared |
| 691 | * by NBD_DO_IT or NBD_CLEAR_SOCK. |
| 692 | */ |
| 693 | BUG_ON(!lo->sock && !list_empty(&lo->queue_head)); |
| 694 | return 0; |
| 695 | |
| 696 | case NBD_PRINT_DEBUG: |
| 697 | printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n", |
| 698 | bdev->bd_disk->disk_name, |
| 699 | lo->queue_head.next, lo->queue_head.prev, |
| 700 | &lo->queue_head); |
| 701 | return 0; |
| 702 | } |
| 703 | return -ENOTTY; |
| 704 | } |
| 705 | |
| 706 | static int nbd_ioctl(struct block_device *bdev, fmode_t mode, |
| 707 | unsigned int cmd, unsigned long arg) |
| 708 | { |
| 709 | struct nbd_device *lo = bdev->bd_disk->private_data; |
| 710 | int error; |
| 711 | |
| 712 | if (!capable(CAP_SYS_ADMIN)) |
| 713 | return -EPERM; |
| 714 | |
| 715 | BUG_ON(lo->magic != LO_MAGIC); |
| 716 | |
| 717 | /* Anyone capable of this syscall can do *real bad* things */ |
| 718 | dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", |
| 719 | lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); |
| 720 | |
| 721 | mutex_lock(&nbd_mutex); |
| 722 | mutex_lock(&lo->tx_lock); |
| 723 | error = __nbd_ioctl(bdev, lo, cmd, arg); |
| 724 | mutex_unlock(&lo->tx_lock); |
| 725 | mutex_unlock(&nbd_mutex); |
| 726 | |
| 727 | return error; |
| 728 | } |
| 729 | |
| 730 | static const struct block_device_operations nbd_fops = |
| 731 | { |
| 732 | .owner = THIS_MODULE, |
| 733 | .ioctl = nbd_ioctl, |
| 734 | }; |
| 735 | |
| 736 | /* |
| 737 | * And here should be modules and kernel interface |
| 738 | * (Just smiley confuses emacs :-) |
| 739 | */ |
| 740 | |
| 741 | static int __init nbd_init(void) |
| 742 | { |
| 743 | int err = -ENOMEM; |
| 744 | int i; |
| 745 | int part_shift; |
| 746 | |
| 747 | BUILD_BUG_ON(sizeof(struct nbd_request) != 28); |
| 748 | |
| 749 | if (max_part < 0) { |
| 750 | printk(KERN_CRIT "nbd: max_part must be >= 0\n"); |
| 751 | return -EINVAL; |
| 752 | } |
| 753 | |
| 754 | nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); |
| 755 | if (!nbd_dev) |
| 756 | return -ENOMEM; |
| 757 | |
| 758 | part_shift = 0; |
| 759 | if (max_part > 0) |
| 760 | part_shift = fls(max_part); |
| 761 | |
| 762 | for (i = 0; i < nbds_max; i++) { |
| 763 | struct gendisk *disk = alloc_disk(1 << part_shift); |
| 764 | if (!disk) |
| 765 | goto out; |
| 766 | nbd_dev[i].disk = disk; |
| 767 | /* |
| 768 | * The new linux 2.5 block layer implementation requires |
| 769 | * every gendisk to have its very own request_queue struct. |
| 770 | * These structs are big so we dynamically allocate them. |
| 771 | */ |
| 772 | disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); |
| 773 | if (!disk->queue) { |
| 774 | put_disk(disk); |
| 775 | goto out; |
| 776 | } |
| 777 | /* |
| 778 | * Tell the block layer that we are not a rotational device |
| 779 | */ |
| 780 | queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); |
| 781 | } |
| 782 | |
| 783 | if (register_blkdev(NBD_MAJOR, "nbd")) { |
| 784 | err = -EIO; |
| 785 | goto out; |
| 786 | } |
| 787 | |
| 788 | printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); |
| 789 | dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); |
| 790 | |
| 791 | for (i = 0; i < nbds_max; i++) { |
| 792 | struct gendisk *disk = nbd_dev[i].disk; |
| 793 | nbd_dev[i].file = NULL; |
| 794 | nbd_dev[i].magic = LO_MAGIC; |
| 795 | nbd_dev[i].flags = 0; |
| 796 | INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); |
| 797 | spin_lock_init(&nbd_dev[i].queue_lock); |
| 798 | INIT_LIST_HEAD(&nbd_dev[i].queue_head); |
| 799 | mutex_init(&nbd_dev[i].tx_lock); |
| 800 | init_waitqueue_head(&nbd_dev[i].active_wq); |
| 801 | init_waitqueue_head(&nbd_dev[i].waiting_wq); |
| 802 | nbd_dev[i].blksize = 1024; |
| 803 | nbd_dev[i].bytesize = 0; |
| 804 | disk->major = NBD_MAJOR; |
| 805 | disk->first_minor = i << part_shift; |
| 806 | disk->fops = &nbd_fops; |
| 807 | disk->private_data = &nbd_dev[i]; |
| 808 | sprintf(disk->disk_name, "nbd%d", i); |
| 809 | set_capacity(disk, 0); |
| 810 | add_disk(disk); |
| 811 | } |
| 812 | |
| 813 | return 0; |
| 814 | out: |
| 815 | while (i--) { |
| 816 | blk_cleanup_queue(nbd_dev[i].disk->queue); |
| 817 | put_disk(nbd_dev[i].disk); |
| 818 | } |
| 819 | kfree(nbd_dev); |
| 820 | return err; |
| 821 | } |
| 822 | |
| 823 | static void __exit nbd_cleanup(void) |
| 824 | { |
| 825 | int i; |
| 826 | for (i = 0; i < nbds_max; i++) { |
| 827 | struct gendisk *disk = nbd_dev[i].disk; |
| 828 | nbd_dev[i].magic = 0; |
| 829 | if (disk) { |
| 830 | del_gendisk(disk); |
| 831 | blk_cleanup_queue(disk->queue); |
| 832 | put_disk(disk); |
| 833 | } |
| 834 | } |
| 835 | unregister_blkdev(NBD_MAJOR, "nbd"); |
| 836 | kfree(nbd_dev); |
| 837 | printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); |
| 838 | } |
| 839 | |
| 840 | module_init(nbd_init); |
| 841 | module_exit(nbd_cleanup); |
| 842 | |
| 843 | MODULE_DESCRIPTION("Network Block Device"); |
| 844 | MODULE_LICENSE("GPL"); |
| 845 | |
| 846 | module_param(nbds_max, int, 0444); |
| 847 | MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); |
| 848 | module_param(max_part, int, 0444); |
| 849 | MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); |
| 850 | #ifndef NDEBUG |
| 851 | module_param(debugflags, int, 0644); |
| 852 | MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); |
| 853 | #endif |