fs/orangefs/waitqueue.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * (C) 2001 Clemson University and The University of Chicago
   4  * (C) 2011 Omnibond Systems
   5  *
   6  * Changes by Acxiom Corporation to implement generic service_operation()
   7  * function, Copyright Acxiom Corporation, 2005.
   8  *
   9  * See COPYING in top-level directory.
  10  */
  11
  12 /*
  13  *  In-kernel waitqueue operations.
  14  */
  15
  16 #include "protocol.h"
  17 #include "orangefs-kernel.h"
  18 #include "orangefs-bufmap.h"
  19
  20 static int wait_for_matching_downcall(struct orangefs_kernel_op_s *, long, bool);
  21 static void orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s *);
  22
  23 /*
  24  * What we do in this function is to walk the list of operations that are
  25  * present in the request queue and mark them as purged.
  26  * NOTE: This is called from the device close after client-core has
  27  * guaranteed that no new operations could appear on the list since the
  28  * client-core is anyway going to exit.
  29  */
  30 void purge_waiting_ops(void)
  31 {
  32         struct orangefs_kernel_op_s *op;
  33
  34         spin_lock(&orangefs_request_list_lock);
  35         list_for_each_entry(op, &orangefs_request_list, list) {
  36                 gossip_debug(GOSSIP_WAIT_DEBUG,
  37                              "pvfs2-client-core: purging op tag %llu %s\n",
  38                              llu(op->tag),
  39                              get_opname_string(op));
  40                 set_op_state_purged(op);
  41                 gossip_debug(GOSSIP_DEV_DEBUG,
  42                              "%s: op:%s: op_state:%d: process:%s:\n",
  43                              __func__,
  44                              get_opname_string(op),
  45                              op->op_state,
  46                              current->comm);
  47         }
  48         spin_unlock(&orangefs_request_list_lock);
  49 }
  50
  51 /*
  52  * submits a ORANGEFS operation and waits for it to complete
  53  *
  54  * Note op->downcall.status will contain the status of the operation (in
  55  * errno format), whether provided by pvfs2-client or a result of failure to
  56  * service the operation.  If the caller wishes to distinguish, then
  57  * op->state can be checked to see if it was serviced or not.
  58  *
  59  * Returns contents of op->downcall.status for convenience
  60  */
  61 int service_operation(struct orangefs_kernel_op_s *op,
  62                       const char *op_name,
  63                       int flags)
  64 {
  65         long timeout = MAX_SCHEDULE_TIMEOUT;
  66         int ret = 0;
  67
  68         DEFINE_WAIT(wait_entry);
  69
  70         op->upcall.tgid = current->tgid;
  71         op->upcall.pid = current->pid;
  72
  73 retry_servicing:
  74         op->downcall.status = 0;
  75         gossip_debug(GOSSIP_WAIT_DEBUG,
  76                      "%s: %s op:%p: process:%s: pid:%d:\n",
  77                      __func__,
  78                      op_name,
  79                      op,
  80                      current->comm,
  81                      current->pid);
  82
  83         /*
  84          * If ORANGEFS_OP_NO_MUTEX was set in flags, we need to avoid
  85          * acquiring the request_mutex because we're servicing a
  86          * high priority remount operation and the request_mutex is
  87          * already taken.
  88          */
  89         if (!(flags & ORANGEFS_OP_NO_MUTEX)) {
  90                 if (flags & ORANGEFS_OP_INTERRUPTIBLE)
  91                         ret = mutex_lock_interruptible(&orangefs_request_mutex);
  92                 else
  93                         ret = mutex_lock_killable(&orangefs_request_mutex);
  94                 /*
  95                  * check to see if we were interrupted while waiting for
  96                  * mutex
  97                  */
  98                 if (ret < 0) {
  99                         op->downcall.status = ret;
 100                         gossip_debug(GOSSIP_WAIT_DEBUG,
 101                                      "%s: service_operation interrupted.\n",
 102                                      __func__);
 103                         return ret;
 104                 }
 105         }
 106
 107         /* queue up the operation */
 108         spin_lock(&orangefs_request_list_lock);
 109         spin_lock(&op->lock);
 110         set_op_state_waiting(op);
 111         gossip_debug(GOSSIP_DEV_DEBUG,
 112                      "%s: op:%s: op_state:%d: process:%s:\n",
 113                      __func__,
 114                      get_opname_string(op),
 115                      op->op_state,
 116                      current->comm);
 117         /* add high priority remount op to the front of the line. */
 118         if (flags & ORANGEFS_OP_PRIORITY)
 119                 list_add(&op->list, &orangefs_request_list);
 120         else
 121                 list_add_tail(&op->list, &orangefs_request_list);
 122         spin_unlock(&op->lock);
 123         wake_up_interruptible(&orangefs_request_list_waitq);
 124         if (!__is_daemon_in_service()) {
 125                 gossip_debug(GOSSIP_WAIT_DEBUG,
 126                              "%s:client core is NOT in service.\n",
 127                              __func__);
 128                 /*
 129                  * Don't wait for the userspace component to return if
 130                  * the filesystem is being umounted anyway.
 131                  */
 132                 if (op->upcall.type == ORANGEFS_VFS_OP_FS_UMOUNT)
 133                         timeout = 0;
 134                 else
 135                         timeout = op_timeout_secs * HZ;
 136         }
 137         spin_unlock(&orangefs_request_list_lock);
 138
 139         if (!(flags & ORANGEFS_OP_NO_MUTEX))
 140                 mutex_unlock(&orangefs_request_mutex);
 141
 142         ret = wait_for_matching_downcall(op, timeout,
 143                                          flags & ORANGEFS_OP_INTERRUPTIBLE);
 144
 145         gossip_debug(GOSSIP_WAIT_DEBUG,
 146                      "%s: wait_for_matching_downcall returned %d for %p\n",
 147                      __func__,
 148                      ret,
 149                      op);
 150
 151         /* got matching downcall; make sure status is in errno format */
 152         if (!ret) {
 153                 spin_unlock(&op->lock);
 154                 op->downcall.status =
 155                     orangefs_normalize_to_errno(op->downcall.status);
 156                 ret = op->downcall.status;
 157                 goto out;
 158         }
 159
 160         /* failed to get matching downcall */
 161         if (ret == -ETIMEDOUT) {
 162                 gossip_err("%s: %s -- wait timed out; aborting attempt.\n",
 163                            __func__,
 164                            op_name);
 165         }
 166
 167         /*
 168          * remove a waiting op from the request list or
 169          * remove an in-progress op from the in-progress list.
 170          */
 171         orangefs_clean_up_interrupted_operation(op);
 172
 173         op->downcall.status = ret;
 174         /* retry if operation has not been serviced and if requested */
 175         if (ret == -EAGAIN) {
 176                 op->attempts++;
 177                 timeout = op_timeout_secs * HZ;
 178                 gossip_debug(GOSSIP_WAIT_DEBUG,
 179                              "orangefs: tag %llu (%s)"
 180                              " -- operation to be retried (%d attempt)\n",
 181                              llu(op->tag),
 182                              op_name,
 183                              op->attempts);
 184
 185                 /*
 186                  * io ops (ops that use the shared memory buffer) have
 187                  * to be returned to their caller for a retry. Other ops
 188                  * can just be recycled here.
 189                  */
 190                 if (!op->uses_shared_memory)
 191                         goto retry_servicing;
 192         }
 193
 194 out:
 195         gossip_debug(GOSSIP_WAIT_DEBUG,
 196                      "%s: %s returning: %d for %p.\n",
 197                      __func__,
 198                      op_name,
 199                      ret,
 200                      op);
 201         return ret;
 202 }
 203
 204 /* This can get called on an I/O op if it had a bad service_operation. */
 205 bool orangefs_cancel_op_in_progress(struct orangefs_kernel_op_s *op)
 206 {
 207         u64 tag = op->tag;
 208         if (!op_state_in_progress(op))
 209                 return false;
 210
 211         op->slot_to_free = op->upcall.req.io.buf_index;
 212         memset(&op->upcall, 0, sizeof(op->upcall));
 213         memset(&op->downcall, 0, sizeof(op->downcall));
 214         op->upcall.type = ORANGEFS_VFS_OP_CANCEL;
 215         op->upcall.req.cancel.op_tag = tag;
 216         op->downcall.type = ORANGEFS_VFS_OP_INVALID;
 217         op->downcall.status = -1;
 218         orangefs_new_tag(op);
 219
 220         spin_lock(&orangefs_request_list_lock);
 221         /* orangefs_request_list_lock is enough of a barrier here */
 222         if (!__is_daemon_in_service()) {
 223                 spin_unlock(&orangefs_request_list_lock);
 224                 return false;
 225         }
 226         spin_lock(&op->lock);
 227         set_op_state_waiting(op);
 228         gossip_debug(GOSSIP_DEV_DEBUG,
 229                      "%s: op:%s: op_state:%d: process:%s:\n",
 230                      __func__,
 231                      get_opname_string(op),
 232                      op->op_state,
 233                      current->comm);
 234         list_add(&op->list, &orangefs_request_list);
 235         spin_unlock(&op->lock);
 236         spin_unlock(&orangefs_request_list_lock);
 237
 238         gossip_debug(GOSSIP_WAIT_DEBUG,
 239                      "Attempting ORANGEFS operation cancellation of tag %llu\n",
 240                      llu(tag));
 241         return true;
 242 }
 243
 244 /*
 245  * Change an op to the "given up" state and remove it from its list.
 246  */
 247 static void
 248         orangefs_clean_up_interrupted_operation(struct orangefs_kernel_op_s *op)
 249 {
 250         /*
 251          * handle interrupted cases depending on what state we were in when
 252          * the interruption is detected.
 253          *
 254          * Called with op->lock held.
 255          */
 256
 257         /*
 258          * List manipulation code elsewhere will ignore ops that
 259          * have been given up upon.
 260          */
 261         op->op_state |= OP_VFS_STATE_GIVEN_UP;
 262
 263         if (list_empty(&op->list)) {
 264                 /* caught copying to/from daemon */
 265                 BUG_ON(op_state_serviced(op));
 266                 spin_unlock(&op->lock);
 267                 wait_for_completion(&op->waitq);
 268         } else if (op_state_waiting(op)) {
 269                 /*
 270                  * upcall hasn't been read; remove op from upcall request
 271                  * list.
 272                  */
 273                 spin_unlock(&op->lock);
 274                 spin_lock(&orangefs_request_list_lock);
 275                 list_del_init(&op->list);
 276                 spin_unlock(&orangefs_request_list_lock);
 277                 gossip_debug(GOSSIP_WAIT_DEBUG,
 278                              "Interrupted: Removed op %p from request_list\n",
 279                              op);
 280         } else if (op_state_in_progress(op)) {
 281                 /* op must be removed from the in progress htable */
 282                 spin_unlock(&op->lock);
 283                 spin_lock(&orangefs_htable_ops_in_progress_lock);
 284                 list_del_init(&op->list);
 285                 spin_unlock(&orangefs_htable_ops_in_progress_lock);
 286                 gossip_debug(GOSSIP_WAIT_DEBUG,
 287                              "Interrupted: Removed op %p"
 288                              " from htable_ops_in_progress\n",
 289                              op);
 290         } else {
 291                 spin_unlock(&op->lock);
 292                 gossip_err("interrupted operation is in a weird state 0x%x\n",
 293                            op->op_state);
 294         }
 295         reinit_completion(&op->waitq);
 296 }
 297
 298 /*
 299  * Sleeps on waitqueue waiting for matching downcall.
 300  * If client-core finishes servicing, then we are good to go.
 301  * else if client-core exits, we get woken up here, and retry with a timeout
 302  *
 303  * When this call returns to the caller, the specified op will no
 304  * longer be in either the in_progress hash table or on the request list.
 305  *
 306  * Returns 0 on success and -errno on failure
 307  * Errors are:
 308  * EAGAIN in case we want the caller to requeue and try again..
 309  * EINTR/EIO/ETIMEDOUT indicating we are done trying to service this
 310  * operation since client-core seems to be exiting too often
 311  * or if we were interrupted.
 312  *
 313  * Returns with op->lock taken.
 314  */
 315 static int wait_for_matching_downcall(struct orangefs_kernel_op_s *op,
 316                                       long timeout,
 317                                       bool interruptible)
 318 {
 319         long n;
 320
 321         /*
 322          * There's a "schedule_timeout" inside of these wait
 323          * primitives, during which the op is out of the hands of the
 324          * user process that needs something done and is being
 325          * manipulated by the client-core process.
 326          */
 327         if (interruptible)
 328                 n = wait_for_completion_interruptible_timeout(&op->waitq,
 329                                                               timeout);
 330         else
 331                 n = wait_for_completion_killable_timeout(&op->waitq, timeout);
 332
 333         spin_lock(&op->lock);
 334
 335         if (op_state_serviced(op))
 336                 return 0;
 337
 338         if (unlikely(n < 0)) {
 339                 gossip_debug(GOSSIP_WAIT_DEBUG,
 340                              "%s: operation interrupted, tag %llu, %p\n",
 341                              __func__,
 342                              llu(op->tag),
 343                              op);
 344                 return -EINTR;
 345         }
 346         if (op_state_purged(op)) {
 347                 gossip_debug(GOSSIP_WAIT_DEBUG,
 348                              "%s: operation purged, tag %llu, %p, %d\n",
 349                              __func__,
 350                              llu(op->tag),
 351                              op,
 352                              op->attempts);
 353                 return (op->attempts < ORANGEFS_PURGE_RETRY_COUNT) ?
 354                          -EAGAIN :
 355                          -EIO;
 356         }
 357         /* must have timed out, then... */
 358         gossip_debug(GOSSIP_WAIT_DEBUG,
 359                      "%s: operation timed out, tag %llu, %p, %d)\n",
 360                      __func__,
 361                      llu(op->tag),
 362                      op,
 363                      op->attempts);
 364         return -ETIMEDOUT;
 365 }