drivers/staging/smbfs/smbiod.c

   1 /*
   2  *  smbiod.c
   3  *
   4  *  Copyright (C) 2000, Charles Loep / Corel Corp.
   5  *  Copyright (C) 2001, Urban Widmark
   6  */
   7
   8
   9 #include <linux/sched.h>
  10 #include <linux/kernel.h>
  11 #include <linux/mm.h>
  12 #include <linux/string.h>
  13 #include <linux/stat.h>
  14 #include <linux/errno.h>
  15 #include <linux/init.h>
  16 #include <linux/file.h>
  17 #include <linux/dcache.h>
  18 #include <linux/module.h>
  19 #include <linux/net.h>
  20 #include <linux/kthread.h>
  21 #include <net/ip.h>
  22
  23 #include <asm/system.h>
  24 #include <asm/uaccess.h>
  25
  26 #include "smb_fs.h"
  27 #include "smbno.h"
  28 #include "smb_mount.h"
  29 #include "smb_debug.h"
  30 #include "request.h"
  31 #include "proto.h"
  32
  33 enum smbiod_state {
  34         SMBIOD_DEAD,
  35         SMBIOD_STARTING,
  36         SMBIOD_RUNNING,
  37 };
  38
  39 static enum smbiod_state smbiod_state = SMBIOD_DEAD;
  40 static struct task_struct *smbiod_thread;
  41 static DECLARE_WAIT_QUEUE_HEAD(smbiod_wait);
  42 static LIST_HEAD(smb_servers);
  43 static DEFINE_SPINLOCK(servers_lock);
  44
  45 #define SMBIOD_DATA_READY       (1<<0)
  46 static unsigned long smbiod_flags;
  47
  48 static int smbiod(void *);
  49 static int smbiod_start(void);
  50
  51 /*
  52  * called when there's work for us to do
  53  */
  54 void smbiod_wake_up(void)
  55 {
  56         if (smbiod_state == SMBIOD_DEAD)
  57                 return;
  58         set_bit(SMBIOD_DATA_READY, &smbiod_flags);
  59         wake_up_interruptible(&smbiod_wait);
  60 }
  61
  62 /*
  63  * start smbiod if none is running
  64  */
  65 static int smbiod_start(void)
  66 {
  67         struct task_struct *tsk;
  68         int err = 0;
  69
  70         if (smbiod_state != SMBIOD_DEAD)
  71                 return 0;
  72         smbiod_state = SMBIOD_STARTING;
  73         __module_get(THIS_MODULE);
  74         spin_unlock(&servers_lock);
  75         tsk = kthread_run(smbiod, NULL, "smbiod");
  76         if (IS_ERR(tsk)) {
  77                 err = PTR_ERR(tsk);
  78                 module_put(THIS_MODULE);
  79         }
  80
  81         spin_lock(&servers_lock);
  82         if (err < 0) {
  83                 smbiod_state = SMBIOD_DEAD;
  84                 smbiod_thread = NULL;
  85         } else {
  86                 smbiod_state = SMBIOD_RUNNING;
  87                 smbiod_thread = tsk;
  88         }
  89         return err;
  90 }
  91
  92 /*
  93  * register a server & start smbiod if necessary
  94  */
  95 int smbiod_register_server(struct smb_sb_info *server)
  96 {
  97         int ret;
  98         spin_lock(&servers_lock);
  99         list_add(&server->entry, &smb_servers);
 100         VERBOSE("%p\n", server);
 101         ret = smbiod_start();
 102         spin_unlock(&servers_lock);
 103         return ret;
 104 }
 105
 106 /*
 107  * Unregister a server
 108  * Must be called with the server lock held.
 109  */
 110 void smbiod_unregister_server(struct smb_sb_info *server)
 111 {
 112         spin_lock(&servers_lock);
 113         list_del_init(&server->entry);
 114         VERBOSE("%p\n", server);
 115         spin_unlock(&servers_lock);
 116
 117         smbiod_wake_up();
 118         smbiod_flush(server);
 119 }
 120
 121 void smbiod_flush(struct smb_sb_info *server)
 122 {
 123         struct list_head *tmp, *n;
 124         struct smb_request *req;
 125
 126         list_for_each_safe(tmp, n, &server->xmitq) {
 127                 req = list_entry(tmp, struct smb_request, rq_queue);
 128                 req->rq_errno = -EIO;
 129                 list_del_init(&req->rq_queue);
 130                 smb_rput(req);
 131                 wake_up_interruptible(&req->rq_wait);
 132         }
 133         list_for_each_safe(tmp, n, &server->recvq) {
 134                 req = list_entry(tmp, struct smb_request, rq_queue);
 135                 req->rq_errno = -EIO;
 136                 list_del_init(&req->rq_queue);
 137                 smb_rput(req);
 138                 wake_up_interruptible(&req->rq_wait);
 139         }
 140 }
 141
 142 /*
 143  * Wake up smbmount and make it reconnect to the server.
 144  * This must be called with the server locked.
 145  *
 146  * FIXME: add smbconnect version to this
 147  */
 148 int smbiod_retry(struct smb_sb_info *server)
 149 {
 150         struct list_head *head;
 151         struct smb_request *req;
 152         struct pid *pid = get_pid(server->conn_pid);
 153         int result = 0;
 154
 155         VERBOSE("state: %d\n", server->state);
 156         if (server->state == CONN_VALID || server->state == CONN_RETRYING)
 157                 goto out;
 158
 159         smb_invalidate_inodes(server);
 160
 161         /*
 162          * Some requests are meaningless after a retry, so we abort them.
 163          * One example are all requests using 'fileid' since the files are
 164          * closed on retry.
 165          */
 166         head = server->xmitq.next;
 167         while (head != &server->xmitq) {
 168                 req = list_entry(head, struct smb_request, rq_queue);
 169                 head = head->next;
 170
 171                 req->rq_bytes_sent = 0;
 172                 if (req->rq_flags & SMB_REQ_NORETRY) {
 173                         VERBOSE("aborting request %p on xmitq\n", req);
 174                         req->rq_errno = -EIO;
 175                         list_del_init(&req->rq_queue);
 176                         smb_rput(req);
 177                         wake_up_interruptible(&req->rq_wait);
 178                 }
 179         }
 180
 181         /*
 182          * FIXME: test the code for retrying request we already sent
 183          */
 184         head = server->recvq.next;
 185         while (head != &server->recvq) {
 186                 req = list_entry(head, struct smb_request, rq_queue);
 187                 head = head->next;
 188 #if 0
 189                 if (req->rq_flags & SMB_REQ_RETRY) {
 190                         /* must move the request to the xmitq */
 191                         VERBOSE("retrying request %p on recvq\n", req);
 192                         list_move(&req->rq_queue, &server->xmitq);
 193                         continue;
 194                 }
 195 #endif
 196
 197                 VERBOSE("aborting request %p on recvq\n", req);
 198                 /* req->rq_rcls = ???; */ /* FIXME: set smb error code too? */
 199                 req->rq_errno = -EIO;
 200                 list_del_init(&req->rq_queue);
 201                 smb_rput(req);
 202                 wake_up_interruptible(&req->rq_wait);
 203         }
 204
 205         smb_close_socket(server);
 206
 207         if (!pid) {
 208                 /* FIXME: this is fatal, umount? */
 209                 printk(KERN_ERR "smb_retry: no connection process\n");
 210                 server->state = CONN_RETRIED;
 211                 goto out;
 212         }
 213
 214         /*
 215          * Change state so that only one retry per server will be started.
 216          */
 217         server->state = CONN_RETRYING;
 218
 219         /*
 220          * Note: use the "priv" flag, as a user process may need to reconnect.
 221          */
 222         result = kill_pid(pid, SIGUSR1, 1);
 223         if (result) {
 224                 /* FIXME: this is most likely fatal, umount? */
 225                 printk(KERN_ERR "smb_retry: signal failed [%d]\n", result);
 226                 goto out;
 227         }
 228         VERBOSE("signalled pid %d\n", pid_nr(pid));
 229
 230         /* FIXME: The retried requests should perhaps get a "time boost". */
 231
 232 out:
 233         put_pid(pid);
 234         return result;
 235 }
 236
 237 /*
 238  * Currently handles lockingX packets.
 239  */
 240 static void smbiod_handle_request(struct smb_sb_info *server)
 241 {
 242         PARANOIA("smbiod got a request ... and we don't implement oplocks!\n");
 243         server->rstate = SMB_RECV_DROP;
 244 }
 245
 246 /*
 247  * Do some IO for one server.
 248  */
 249 static void smbiod_doio(struct smb_sb_info *server)
 250 {
 251         int result;
 252         int maxwork = 7;
 253
 254         if (server->state != CONN_VALID)
 255                 goto out;
 256
 257         do {
 258                 result = smb_request_recv(server);
 259                 if (result < 0) {
 260                         server->state = CONN_INVALID;
 261                         smbiod_retry(server);
 262                         goto out;       /* reconnecting is slow */
 263                 } else if (server->rstate == SMB_RECV_REQUEST)
 264                         smbiod_handle_request(server);
 265         } while (result > 0 && maxwork-- > 0);
 266
 267         /*
 268          * If there is more to read then we want to be sure to wake up again.
 269          */
 270         if (server->state != CONN_VALID)
 271                 goto out;
 272         if (smb_recv_available(server) > 0)
 273                 set_bit(SMBIOD_DATA_READY, &smbiod_flags);
 274
 275         do {
 276                 result = smb_request_send_server(server);
 277                 if (result < 0) {
 278                         server->state = CONN_INVALID;
 279                         smbiod_retry(server);
 280                         goto out;       /* reconnecting is slow */
 281                 }
 282         } while (result > 0);
 283
 284         /*
 285          * If the last request was not sent out we want to wake up again.
 286          */
 287         if (!list_empty(&server->xmitq))
 288                 set_bit(SMBIOD_DATA_READY, &smbiod_flags);
 289
 290 out:
 291         return;
 292 }
 293
 294 /*
 295  * smbiod kernel thread
 296  */
 297 static int smbiod(void *unused)
 298 {
 299         VERBOSE("SMB Kernel thread starting (%d) ...\n", current->pid);
 300
 301         for (;;) {
 302                 struct smb_sb_info *server;
 303                 struct list_head *pos, *n;
 304
 305                 /* FIXME: Use poll? */
 306                 wait_event_interruptible(smbiod_wait,
 307                          test_bit(SMBIOD_DATA_READY, &smbiod_flags));
 308                 if (signal_pending(current)) {
 309                         spin_lock(&servers_lock);
 310                         smbiod_state = SMBIOD_DEAD;
 311                         spin_unlock(&servers_lock);
 312                         break;
 313                 }
 314
 315                 clear_bit(SMBIOD_DATA_READY, &smbiod_flags);
 316
 317                 spin_lock(&servers_lock);
 318                 if (list_empty(&smb_servers)) {
 319                         smbiod_state = SMBIOD_DEAD;
 320                         spin_unlock(&servers_lock);
 321                         break;
 322                 }
 323
 324                 list_for_each_safe(pos, n, &smb_servers) {
 325                         server = list_entry(pos, struct smb_sb_info, entry);
 326                         VERBOSE("checking server %p\n", server);
 327
 328                         if (server->state == CONN_VALID) {
 329                                 spin_unlock(&servers_lock);
 330
 331                                 smb_lock_server(server);
 332                                 smbiod_doio(server);
 333                                 smb_unlock_server(server);
 334
 335                                 spin_lock(&servers_lock);
 336                         }
 337                 }
 338                 spin_unlock(&servers_lock);
 339         }
 340
 341         VERBOSE("SMB Kernel thread exiting (%d) ...\n", current->pid);
 342         module_put_and_exit(0);
 343 }