drivers/block/nbd.c

   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 Pavel Machek <pavel@ucw.cz>
   8  * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
   9  *
  10  * (part of code stolen from loop.c)
  11  *
  12  * 97-3-25 compiled 0-th version, not yet tested it
  13  *   (it did not work, BTW) (later that day) HEY! it works!
  14  *   (bit later) hmm, not that much... 2:00am next day:
  15  *   yes, it works, but it gives something like 50kB/sec
  16  * 97-4-01 complete rewrite to make it possible for many requests at
  17  *   once to be processed
  18  * 97-4-11 Making protocol independent of endianity etc.
  19  * 97-9-13 Cosmetic changes
  20  * 98-5-13 Attempt to make 64-bit-clean on 64-bit machines
  21  * 99-1-11 Attempt to make 64-bit-clean on 32-bit machines <ankry@mif.pg.gda.pl>
  22  * 01-2-27 Fix to store proper blockcount for kernel (calculated using
  23  *   BLOCK_SIZE_BITS, not device blocksize) <aga@permonline.ru>
  24  * 01-3-11 Make nbd work with new Linux block layer code. It now supports
  25  *   plugging like all the other block devices. Also added in MSG_MORE to
  26  *   reduce number of partial TCP segments sent. <steve@chygwyn.com>
  27  * 01-12-6 Fix deadlock condition by making queue locks independent of
  28  *   the transmit lock. <steve@chygwyn.com>
  29  * 02-10-11 Allow hung xmit to be aborted via SIGKILL & various fixes.
  30  *   <Paul.Clements@SteelEye.com> <James.Bottomley@SteelEye.com>
  31  * 03-06-22 Make nbd work with new linux 2.5 block layer design. This fixes
  32  *   memory corruption from module removal and possible memory corruption
  33  *   from sending/receiving disk data. <ldl@aros.net>
  34  * 03-06-23 Cosmetic changes. <ldl@aros.net>
  35  * 03-06-23 Enhance diagnostics support. <ldl@aros.net>
  36  * 03-06-24 Remove unneeded blksize_bits field from nbd_device struct.
  37  *   <ldl@aros.net>
  38  * 03-06-24 Cleanup PARANOIA usage & code. <ldl@aros.net>
  39  * 04-02-19 Remove PARANOIA, plus various cleanups (Paul Clements)
  40  * possible FIXME: make set_sock / set_blksize / set_size / do_it one syscall
  41  * why not: would need verify_area and friends, would share yet another
  42  *          structure with userland
  43  */
  44
  45 #include <linux/major.h>
  46
  47 #include <linux/blkdev.h>
  48 #include <linux/module.h>
  49 #include <linux/init.h>
  50 #include <linux/sched.h>
  51 #include <linux/fs.h>
  52 #include <linux/bio.h>
  53 #include <linux/stat.h>
  54 #include <linux/errno.h>
  55 #include <linux/file.h>
  56 #include <linux/ioctl.h>
  57 #include <net/sock.h>
  58
  59 #include <linux/devfs_fs_kernel.h>
  60
  61 #include <asm/uaccess.h>
  62 #include <asm/types.h>
  63
  64 #include <linux/nbd.h>
  65
  66 #define LO_MAGIC 0x68797548
  67
  68 #ifdef NDEBUG
  69 #define dprintk(flags, fmt...)
  70 #else /* NDEBUG */
  71 #define dprintk(flags, fmt...) do { \
  72         if (debugflags & (flags)) printk(KERN_DEBUG fmt); \
  73 } while (0)
  74 #define DBG_IOCTL       0x0004
  75 #define DBG_INIT        0x0010
  76 #define DBG_EXIT        0x0020
  77 #define DBG_BLKDEV      0x0100
  78 #define DBG_RX          0x0200
  79 #define DBG_TX          0x0400
  80 static unsigned int debugflags;
  81 #endif /* NDEBUG */
  82
  83 static struct nbd_device nbd_dev[MAX_NBD];
  84
  85 /*
  86  * Use just one lock (or at most 1 per NIC). Two arguments for this:
  87  * 1. Each NIC is essentially a synchronization point for all servers
  88  *    accessed through that NIC so there's no need to have more locks
  89  *    than NICs anyway.
  90  * 2. More locks lead to more "Dirty cache line bouncing" which will slow
  91  *    down each lock to the point where they're actually slower than just
  92  *    a single lock.
  93  * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this!
  94  */
  95 static spinlock_t nbd_lock = SPIN_LOCK_UNLOCKED;
  96
  97 #ifndef NDEBUG
  98 static const char *ioctl_cmd_to_ascii(int cmd)
  99 {
 100         switch (cmd) {
 101         case NBD_SET_SOCK: return "set-sock";
 102         case NBD_SET_BLKSIZE: return "set-blksize";
 103         case NBD_SET_SIZE: return "set-size";
 104         case NBD_DO_IT: return "do-it";
 105         case NBD_CLEAR_SOCK: return "clear-sock";
 106         case NBD_CLEAR_QUE: return "clear-que";
 107         case NBD_PRINT_DEBUG: return "print-debug";
 108         case NBD_SET_SIZE_BLOCKS: return "set-size-blocks";
 109         case NBD_DISCONNECT: return "disconnect";
 110         case BLKROSET: return "set-read-only";
 111         case BLKFLSBUF: return "flush-buffer-cache";
 112         }
 113         return "unknown";
 114 }
 115
 116 static const char *nbdcmd_to_ascii(int cmd)
 117 {
 118         switch (cmd) {
 119         case  NBD_CMD_READ: return "read";
 120         case NBD_CMD_WRITE: return "write";
 121         case  NBD_CMD_DISC: return "disconnect";
 122         }
 123         return "invalid";
 124 }
 125 #endif /* NDEBUG */
 126
 127 static void nbd_end_request(struct request *req)
 128 {
 129         int uptodate = (req->errors == 0) ? 1 : 0;
 130         request_queue_t *q = req->q;
 131         struct nbd_device *lo = req->rq_disk->private_data;
 132         unsigned long flags;
 133
 134         dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
 135                         req, uptodate? "done": "failed");
 136
 137         spin_lock(&lo->queue_lock);
 138         while (req->ref_count > 1) { /* still in send */
 139                 spin_unlock(&lo->queue_lock);
 140                 printk(KERN_DEBUG "%s: request %p still in use (%d), waiting\n",
 141                     lo->disk->disk_name, req, req->ref_count);
 142                 set_current_state(TASK_UNINTERRUPTIBLE);
 143                 schedule_timeout(HZ); /* wait a second */
 144                 spin_lock(&lo->queue_lock);
 145         }
 146         spin_unlock(&lo->queue_lock);
 147
 148         spin_lock_irqsave(q->queue_lock, flags);
 149         if (!end_that_request_first(req, uptodate, req->nr_sectors)) {
 150                 end_that_request_last(req);
 151         }
 152         spin_unlock_irqrestore(q->queue_lock, flags);
 153 }
 154
 155 /*
 156  *  Send or receive packet.
 157  */
 158 static int sock_xmit(struct socket *sock, int send, void *buf, int size,
 159                 int msg_flags)
 160 {
 161         int result;
 162         struct msghdr msg;
 163         struct kvec iov;
 164         unsigned long flags;
 165         sigset_t oldset;
 166
 167         /* Allow interception of SIGKILL only
 168          * Don't allow other signals to interrupt the transmission */
 169         spin_lock_irqsave(&current->sighand->siglock, flags);
 170         oldset = current->blocked;
 171         sigfillset(&current->blocked);
 172         sigdelsetmask(&current->blocked, sigmask(SIGKILL));
 173         recalc_sigpending();
 174         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 175
 176         do {
 177                 sock->sk->sk_allocation = GFP_NOIO;
 178                 iov.iov_base = buf;
 179                 iov.iov_len = size;
 180                 msg.msg_name = NULL;
 181                 msg.msg_namelen = 0;
 182                 msg.msg_control = NULL;
 183                 msg.msg_controllen = 0;
 184                 msg.msg_namelen = 0;
 185                 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
 186
 187                 if (send)
 188                         result = kernel_sendmsg(sock, &msg, &iov, 1, size);
 189                 else
 190                         result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0);
 191
 192                 if (signal_pending(current)) {
 193                         siginfo_t info;
 194                         spin_lock_irqsave(&current->sighand->siglock, flags);
 195                         printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
 196                                 current->pid, current->comm,
 197                                 dequeue_signal(current, &current->blocked, &info));
 198                         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 199                         result = -EINTR;
 200                         break;
 201                 }
 202
 203                 if (result <= 0) {
 204                         if (result == 0)
 205                                 result = -EPIPE; /* short read */
 206                         break;
 207                 }
 208                 size -= result;
 209                 buf += result;
 210         } while (size > 0);
 211
 212         spin_lock_irqsave(&current->sighand->siglock, flags);
 213         current->blocked = oldset;
 214         recalc_sigpending();
 215         spin_unlock_irqrestore(&current->sighand->siglock, flags);
 216
 217         return result;
 218 }
 219
 220 static inline int sock_send_bvec(struct socket *sock, struct bio_vec *bvec,
 221                 int flags)
 222 {
 223         int result;
 224         void *kaddr = kmap(bvec->bv_page);
 225         result = sock_xmit(sock, 1, kaddr + bvec->bv_offset, bvec->bv_len,
 226                         flags);
 227         kunmap(bvec->bv_page);
 228         return result;
 229 }
 230
 231 void nbd_send_req(struct nbd_device *lo, struct request *req)
 232 {
 233         int result, i, flags;
 234         struct nbd_request request;
 235         unsigned long size = req->nr_sectors << 9;
 236         struct socket *sock = lo->sock;
 237
 238         request.magic = htonl(NBD_REQUEST_MAGIC);
 239         request.type = htonl(nbd_cmd(req));
 240         request.from = cpu_to_be64((u64) req->sector << 9);
 241         request.len = htonl(size);
 242         memcpy(request.handle, &req, sizeof(req));
 243
 244         down(&lo->tx_lock);
 245
 246         if (!sock || !lo->sock) {
 247                 printk(KERN_ERR "%s: Attempted send on closed socket\n",
 248                                 lo->disk->disk_name);
 249                 goto error_out;
 250         }
 251
 252         dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n",
 253                         lo->disk->disk_name, req,
 254                         nbdcmd_to_ascii(nbd_cmd(req)),
 255                         (unsigned long long)req->sector << 9,
 256                         req->nr_sectors << 9);
 257         result = sock_xmit(sock, 1, &request, sizeof(request),
 258                         (nbd_cmd(req) == NBD_CMD_WRITE)? MSG_MORE: 0);
 259         if (result <= 0) {
 260                 printk(KERN_ERR "%s: Send control failed (result %d)\n",
 261                                 lo->disk->disk_name, result);
 262                 goto error_out;
 263         }
 264
 265         if (nbd_cmd(req) == NBD_CMD_WRITE) {
 266                 struct bio *bio;
 267                 /*
 268                  * we are really probing at internals to determine
 269                  * whether to set MSG_MORE or not...
 270                  */
 271                 rq_for_each_bio(bio, req) {
 272                         struct bio_vec *bvec;
 273                         bio_for_each_segment(bvec, bio, i) {
 274                                 flags = 0;
 275                                 if ((i < (bio->bi_vcnt - 1)) || bio->bi_next)
 276                                         flags = MSG_MORE;
 277                                 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
 278                                                 lo->disk->disk_name, req,
 279                                                 bvec->bv_len);
 280                                 result = sock_send_bvec(sock, bvec, flags);
 281                                 if (result <= 0) {
 282                                         printk(KERN_ERR "%s: Send data failed (result %d)\n",
 283                                                         lo->disk->disk_name,
 284                                                         result);
 285                                         goto error_out;
 286                                 }
 287                         }
 288                 }
 289         }
 290         up(&lo->tx_lock);
 291         return;
 292
 293 error_out:
 294         up(&lo->tx_lock);
 295         req->errors++;
 296 }
 297
 298 static struct request *nbd_find_request(struct nbd_device *lo, char *handle)
 299 {
 300         struct request *req;
 301         struct list_head *tmp;
 302         struct request *xreq;
 303
 304         memcpy(&xreq, handle, sizeof(xreq));
 305
 306         spin_lock(&lo->queue_lock);
 307         list_for_each(tmp, &lo->queue_head) {
 308                 req = list_entry(tmp, struct request, queuelist);
 309                 if (req != xreq)
 310                         continue;
 311                 list_del_init(&req->queuelist);
 312                 spin_unlock(&lo->queue_lock);
 313                 return req;
 314         }
 315         spin_unlock(&lo->queue_lock);
 316         return NULL;
 317 }
 318
 319 static inline int sock_recv_bvec(struct socket *sock, struct bio_vec *bvec)
 320 {
 321         int result;
 322         void *kaddr = kmap(bvec->bv_page);
 323         result = sock_xmit(sock, 0, kaddr + bvec->bv_offset, bvec->bv_len,
 324                         MSG_WAITALL);
 325         kunmap(bvec->bv_page);
 326         return result;
 327 }
 328
 329 /* NULL returned = something went wrong, inform userspace */
 330 struct request *nbd_read_stat(struct nbd_device *lo)
 331 {
 332         int result;
 333         struct nbd_reply reply;
 334         struct request *req;
 335         struct socket *sock = lo->sock;
 336
 337         reply.magic = 0;
 338         result = sock_xmit(sock, 0, &reply, sizeof(reply), MSG_WAITALL);
 339         if (result <= 0) {
 340                 printk(KERN_ERR "%s: Receive control failed (result %d)\n",
 341                                 lo->disk->disk_name, result);
 342                 goto harderror;
 343         }
 344         req = nbd_find_request(lo, reply.handle);
 345         if (req == NULL) {
 346                 printk(KERN_ERR "%s: Unexpected reply (%p)\n",
 347                                 lo->disk->disk_name, reply.handle);
 348                 result = -EBADR;
 349                 goto harderror;
 350         }
 351
 352         if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
 353                 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n",
 354                                 lo->disk->disk_name,
 355                                 (unsigned long)ntohl(reply.magic));
 356                 result = -EPROTO;
 357                 goto harderror;
 358         }
 359         if (ntohl(reply.error)) {
 360                 printk(KERN_ERR "%s: Other side returned error (%d)\n",
 361                                 lo->disk->disk_name, ntohl(reply.error));
 362                 req->errors++;
 363                 return req;
 364         }
 365
 366         dprintk(DBG_RX, "%s: request %p: got reply\n",
 367                         lo->disk->disk_name, req);
 368         if (nbd_cmd(req) == NBD_CMD_READ) {
 369                 int i;
 370                 struct bio *bio;
 371                 rq_for_each_bio(bio, req) {
 372                         struct bio_vec *bvec;
 373                         bio_for_each_segment(bvec, bio, i) {
 374                                 result = sock_recv_bvec(sock, bvec);
 375                                 if (result <= 0) {
 376                                         printk(KERN_ERR "%s: Receive data failed (result %d)\n",
 377                                                         lo->disk->disk_name,
 378                                                         result);
 379                                         goto harderror;
 380                                 }
 381                                 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
 382                                         lo->disk->disk_name, req, bvec->bv_len);
 383                         }
 384                 }
 385         }
 386         return req;
 387 harderror:
 388         lo->harderror = result;
 389         return NULL;
 390 }
 391
 392 void nbd_do_it(struct nbd_device *lo)
 393 {
 394         struct request *req;
 395
 396         BUG_ON(lo->magic != LO_MAGIC);
 397
 398         while ((req = nbd_read_stat(lo)) != NULL)
 399                 nbd_end_request(req);
 400         return;
 401 }
 402
 403 void nbd_clear_que(struct nbd_device *lo)
 404 {
 405         struct request *req;
 406
 407         BUG_ON(lo->magic != LO_MAGIC);
 408
 409         do {
 410                 req = NULL;
 411                 spin_lock(&lo->queue_lock);
 412                 if (!list_empty(&lo->queue_head)) {
 413                         req = list_entry(lo->queue_head.next, struct request, queuelist);
 414                         list_del_init(&req->queuelist);
 415                 }
 416                 spin_unlock(&lo->queue_lock);
 417                 if (req) {
 418                         req->errors++;
 419                         nbd_end_request(req);
 420                 }
 421         } while (req);
 422 }
 423
 424 /*
 425  * We always wait for result of write, for now. It would be nice to make it optional
 426  * in future
 427  * if ((req->cmd == WRITE) && (lo->flags & NBD_WRITE_NOCHK))
 428  *   { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); }
 429  */
 430
 431 static void do_nbd_request(request_queue_t * q)
 432 {
 433         struct request *req;
 434
 435         while ((req = elv_next_request(q)) != NULL) {
 436                 struct nbd_device *lo;
 437
 438                 blkdev_dequeue_request(req);
 439                 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%lx)\n",
 440                                 req->rq_disk->disk_name, req, req->flags);
 441
 442                 if (!(req->flags & REQ_CMD))
 443                         goto error_out;
 444
 445                 lo = req->rq_disk->private_data;
 446
 447                 BUG_ON(lo->magic != LO_MAGIC);
 448
 449                 if (!lo->file) {
 450                         printk(KERN_ERR "%s: Request when not-ready\n",
 451                                         lo->disk->disk_name);
 452                         goto error_out;
 453                 }
 454                 nbd_cmd(req) = NBD_CMD_READ;
 455                 if (rq_data_dir(req) == WRITE) {
 456                         nbd_cmd(req) = NBD_CMD_WRITE;
 457                         if (lo->flags & NBD_READ_ONLY) {
 458                                 printk(KERN_ERR "%s: Write on read-only\n",
 459                                                 lo->disk->disk_name);
 460                                 goto error_out;
 461                         }
 462                 }
 463
 464                 req->errors = 0;
 465                 spin_unlock_irq(q->queue_lock);
 466
 467                 spin_lock(&lo->queue_lock);
 468
 469                 if (!lo->file) {
 470                         spin_unlock(&lo->queue_lock);
 471                         printk(KERN_ERR "%s: failed between accept and semaphore, file lost\n",
 472                                         lo->disk->disk_name);
 473                         req->errors++;
 474                         nbd_end_request(req);
 475                         spin_lock_irq(q->queue_lock);
 476                         continue;
 477                 }
 478
 479                 list_add(&req->queuelist, &lo->queue_head);
 480                 req->ref_count++; /* make sure req does not get freed */
 481                 spin_unlock(&lo->queue_lock);
 482
 483                 nbd_send_req(lo, req);
 484
 485                 if (req->errors) {
 486                         printk(KERN_ERR "%s: Request send failed\n",
 487                                         lo->disk->disk_name);
 488                         spin_lock(&lo->queue_lock);
 489                         list_del_init(&req->queuelist);
 490                         req->ref_count--;
 491                         spin_unlock(&lo->queue_lock);
 492                         nbd_end_request(req);
 493                         spin_lock_irq(q->queue_lock);
 494                         continue;
 495                 }
 496
 497                 spin_lock(&lo->queue_lock);
 498                 req->ref_count--;
 499                 spin_unlock(&lo->queue_lock);
 500                 spin_lock_irq(q->queue_lock);
 501                 continue;
 502
 503 error_out:
 504                 req->errors++;
 505                 spin_unlock(q->queue_lock);
 506                 nbd_end_request(req);
 507                 spin_lock(q->queue_lock);
 508         }
 509         return;
 510 }
 511
 512 static int nbd_ioctl(struct inode *inode, struct file *file,
 513                      unsigned int cmd, unsigned long arg)
 514 {
 515         struct nbd_device *lo = inode->i_bdev->bd_disk->private_data;
 516         int error;
 517         struct request sreq ;
 518
 519         if (!capable(CAP_SYS_ADMIN))
 520                 return -EPERM;
 521
 522         BUG_ON(lo->magic != LO_MAGIC);
 523
 524         /* Anyone capable of this syscall can do *real bad* things */
 525         dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
 526                         lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
 527
 528         switch (cmd) {
 529         case NBD_DISCONNECT:
 530                 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name);
 531                 sreq.flags = REQ_SPECIAL;
 532                 nbd_cmd(&sreq) = NBD_CMD_DISC;
 533                 /*
 534                  * Set these to sane values in case server implementation
 535                  * fails to check the request type first and also to keep
 536                  * debugging output cleaner.
 537                  */
 538                 sreq.sector = 0;
 539                 sreq.nr_sectors = 0;
 540                 if (!lo->sock)
 541                         return -EINVAL;
 542                 nbd_send_req(lo, &sreq);
 543                 return 0;
 544
 545         case NBD_CLEAR_SOCK:
 546                 error = 0;
 547                 down(&lo->tx_lock);
 548                 lo->sock = NULL;
 549                 up(&lo->tx_lock);
 550                 spin_lock(&lo->queue_lock);
 551                 file = lo->file;
 552                 lo->file = NULL;
 553                 spin_unlock(&lo->queue_lock);
 554                 nbd_clear_que(lo);
 555                 spin_lock(&lo->queue_lock);
 556                 if (!list_empty(&lo->queue_head)) {
 557                         printk(KERN_ERR "nbd: disconnect: some requests are in progress -> please try again.\n");
 558                         error = -EBUSY;
 559                 }
 560                 spin_unlock(&lo->queue_lock);
 561                 if (file)
 562                         fput(file);
 563                 return error;
 564         case NBD_SET_SOCK:
 565                 if (lo->file)
 566                         return -EBUSY;
 567                 error = -EINVAL;
 568                 file = fget(arg);
 569                 if (file) {
 570                         inode = file->f_dentry->d_inode;
 571                         if (inode->i_sock) {
 572                                 lo->file = file;
 573                                 lo->sock = SOCKET_I(inode);
 574                                 error = 0;
 575                         } else {
 576                                 fput(file);
 577                         }
 578                 }
 579                 return error;
 580         case NBD_SET_BLKSIZE:
 581                 lo->blksize = arg;
 582                 lo->bytesize &= ~(lo->blksize-1);
 583                 inode->i_bdev->bd_inode->i_size = lo->bytesize;
 584                 set_blocksize(inode->i_bdev, lo->blksize);
 585                 set_capacity(lo->disk, lo->bytesize >> 9);
 586                 return 0;
 587         case NBD_SET_SIZE:
 588                 lo->bytesize = arg & ~(lo->blksize-1);
 589                 inode->i_bdev->bd_inode->i_size = lo->bytesize;
 590                 set_blocksize(inode->i_bdev, lo->blksize);
 591                 set_capacity(lo->disk, lo->bytesize >> 9);
 592                 return 0;
 593         case NBD_SET_SIZE_BLOCKS:
 594                 lo->bytesize = ((u64) arg) * lo->blksize;
 595                 inode->i_bdev->bd_inode->i_size = lo->bytesize;
 596                 set_blocksize(inode->i_bdev, lo->blksize);
 597                 set_capacity(lo->disk, lo->bytesize >> 9);
 598                 return 0;
 599         case NBD_DO_IT:
 600                 if (!lo->file)
 601                         return -EINVAL;
 602                 nbd_do_it(lo);
 603                 /* on return tidy up in case we have a signal */
 604                 /* Forcibly shutdown the socket causing all listeners
 605                  * to error
 606                  *
 607                  * FIXME: This code is duplicated from sys_shutdown, but
 608                  * there should be a more generic interface rather than
 609                  * calling socket ops directly here */
 610                 down(&lo->tx_lock);
 611                 if (lo->sock) {
 612                         printk(KERN_WARNING "%s: shutting down socket\n",
 613                                 lo->disk->disk_name);
 614                         lo->sock->ops->shutdown(lo->sock,
 615                                 SEND_SHUTDOWN|RCV_SHUTDOWN);
 616                         lo->sock = NULL;
 617                 }
 618                 up(&lo->tx_lock);
 619                 spin_lock(&lo->queue_lock);
 620                 file = lo->file;
 621                 lo->file = NULL;
 622                 spin_unlock(&lo->queue_lock);
 623                 nbd_clear_que(lo);
 624                 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name);
 625                 if (file)
 626                         fput(file);
 627                 return lo->harderror;
 628         case NBD_CLEAR_QUE:
 629                 down(&lo->tx_lock);
 630                 if (lo->sock) {
 631                         up(&lo->tx_lock);
 632                         return 0; /* probably should be error, but that would
 633                                    * break "nbd-client -d", so just return 0 */
 634                 }
 635                 up(&lo->tx_lock);
 636                 nbd_clear_que(lo);
 637                 return 0;
 638         case NBD_PRINT_DEBUG:
 639                 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n",
 640                         inode->i_bdev->bd_disk->disk_name,
 641                         lo->queue_head.next, lo->queue_head.prev,
 642                         &lo->queue_head);
 643                 return 0;
 644         }
 645         return -EINVAL;
 646 }
 647
 648 static struct block_device_operations nbd_fops =
 649 {
 650         .owner =        THIS_MODULE,
 651         .ioctl =        nbd_ioctl,
 652 };
 653
 654 /*
 655  * And here should be modules and kernel interface
 656  *  (Just smiley confuses emacs :-)
 657  */
 658
 659 static int __init nbd_init(void)
 660 {
 661         int err = -ENOMEM;
 662         int i;
 663
 664         if (sizeof(struct nbd_request) != 28) {
 665                 printk(KERN_CRIT "nbd: sizeof nbd_request needs to be 28 in order to work!\n" );
 666                 return -EIO;
 667         }
 668
 669         for (i = 0; i < MAX_NBD; i++) {
 670                 struct gendisk *disk = alloc_disk(1);
 671                 if (!disk)
 672                         goto out;
 673                 nbd_dev[i].disk = disk;
 674                 /*
 675                  * The new linux 2.5 block layer implementation requires
 676                  * every gendisk to have its very own request_queue struct.
 677                  * These structs are big so we dynamically allocate them.
 678                  */
 679                 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock);
 680                 if (!disk->queue) {
 681                         put_disk(disk);
 682                         goto out;
 683                 }
 684         }
 685
 686         if (register_blkdev(NBD_MAJOR, "nbd")) {
 687                 err = -EIO;
 688                 goto out;
 689         }
 690
 691         printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
 692         dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
 693
 694         devfs_mk_dir("nbd");
 695         for (i = 0; i < MAX_NBD; i++) {
 696                 struct gendisk *disk = nbd_dev[i].disk;
 697                 nbd_dev[i].file = NULL;
 698                 nbd_dev[i].magic = LO_MAGIC;
 699                 nbd_dev[i].flags = 0;
 700                 spin_lock_init(&nbd_dev[i].queue_lock);
 701                 INIT_LIST_HEAD(&nbd_dev[i].queue_head);
 702                 init_MUTEX(&nbd_dev[i].tx_lock);
 703                 nbd_dev[i].blksize = 1024;
 704                 nbd_dev[i].bytesize = 0x7ffffc00ULL << 10; /* 2TB */
 705                 disk->major = NBD_MAJOR;
 706                 disk->first_minor = i;
 707                 disk->fops = &nbd_fops;
 708                 disk->private_data = &nbd_dev[i];
 709                 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
 710                 sprintf(disk->disk_name, "nbd%d", i);
 711                 sprintf(disk->devfs_name, "nbd/%d", i);
 712                 set_capacity(disk, 0x7ffffc00ULL << 1); /* 2 TB */
 713                 add_disk(disk);
 714         }
 715
 716         return 0;
 717 out:
 718         while (i--) {
 719                 blk_cleanup_queue(nbd_dev[i].disk->queue);
 720                 put_disk(nbd_dev[i].disk);
 721         }
 722         return err;
 723 }
 724
 725 static void __exit nbd_cleanup(void)
 726 {
 727         int i;
 728         for (i = 0; i < MAX_NBD; i++) {
 729                 struct gendisk *disk = nbd_dev[i].disk;
 730                 if (disk) {
 731                         del_gendisk(disk);
 732                         blk_cleanup_queue(disk->queue);
 733                         put_disk(disk);
 734                 }
 735         }
 736         devfs_remove("nbd");
 737         unregister_blkdev(NBD_MAJOR, "nbd");
 738         printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
 739 }
 740
 741 module_init(nbd_init);
 742 module_exit(nbd_cleanup);
 743
 744 MODULE_DESCRIPTION("Network Block Device");
 745 MODULE_LICENSE("GPL");
 746
 747 #ifndef NDEBUG
 748 MODULE_PARM(debugflags, "i");
 749 MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
 750 #endif