lustre/include/lustre_lib.h

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2013, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * lustre/include/lustre_lib.h
  37  *
  38  * Basic Lustre library routines.
  39  */
  40
  41 #ifndef _LUSTRE_LIB_H
  42 #define _LUSTRE_LIB_H
  43
  44 /** \defgroup lib lib
  45  *
  46  * @{
  47  */
  48
  49 #include <linux/signal.h>
  50 #include <libcfs/libcfs.h>
  51 #include <lustre/lustre_idl.h>
  52 #include <lustre_ver.h>
  53 #include <lustre_cfg.h>
  54
  55 /* target.c */
  56 struct ptlrpc_request;
  57 struct obd_export;
  58 struct lu_target;
  59 struct l_wait_info;
  60 #include <lustre_ha.h>
  61 #include <lustre_net.h>
  62
  63 #ifdef HAVE_SERVER_SUPPORT
  64 void target_client_add_cb(struct obd_device *obd, __u64 transno, void *cb_data,
  65                           int error);
  66 int target_handle_connect(struct ptlrpc_request *req);
  67 int target_handle_disconnect(struct ptlrpc_request *req);
  68 void target_destroy_export(struct obd_export *exp);
  69 int target_handle_ping(struct ptlrpc_request *req);
  70 void target_committed_to_req(struct ptlrpc_request *req);
  71 void target_cancel_recovery_timer(struct obd_device *obd);
  72 void target_stop_recovery_thread(struct obd_device *obd);
  73 void target_cleanup_recovery(struct obd_device *obd);
  74 int target_queue_recovery_request(struct ptlrpc_request *req,
  75                                   struct obd_device *obd);
  76 int target_bulk_io(struct obd_export *exp, struct ptlrpc_bulk_desc *desc,
  77                    struct l_wait_info *lwi);
  78 #endif
  79
  80 int target_pack_pool_reply(struct ptlrpc_request *req);
  81 int do_set_info_async(struct obd_import *imp,
  82                       int opcode, int version,
  83                       size_t keylen, void *key,
  84                       size_t vallen, void *val,
  85                       struct ptlrpc_request_set *set);
  86
  87 void target_send_reply(struct ptlrpc_request *req, int rc, int fail_id);
  88
  89 /*
  90  * l_wait_event is a flexible sleeping function, permitting simple caller
  91  * configuration of interrupt and timeout sensitivity along with actions to
  92  * be performed in the event of either exception.
  93  *
  94  * The first form of usage looks like this:
  95  *
  96  * struct l_wait_info lwi = LWI_TIMEOUT_INTR(timeout, timeout_handler,
  97  *                                           intr_handler, callback_data);
  98  * rc = l_wait_event(waitq, condition, &lwi);
  99  *
 100  * l_wait_event() makes the current process wait on 'waitq' until 'condition'
 101  * is TRUE or a "killable" signal (SIGTERM, SIKGILL, SIGINT) is pending.  It
 102  * returns 0 to signify 'condition' is TRUE, but if a signal wakes it before
 103  * 'condition' becomes true, it optionally calls the specified 'intr_handler'
 104  * if not NULL, and returns -EINTR.
 105  *
 106  * If a non-zero timeout is specified, signals are ignored until the timeout
 107  * has expired.  At this time, if 'timeout_handler' is not NULL it is called.
 108  * If it returns FALSE l_wait_event() continues to wait as described above with
 109  * signals enabled.  Otherwise it returns -ETIMEDOUT.
 110  *
 111  * LWI_INTR(intr_handler, callback_data) is shorthand for
 112  * LWI_TIMEOUT_INTR(0, NULL, intr_handler, callback_data)
 113  *
 114  * The second form of usage looks like this:
 115  *
 116  * struct l_wait_info lwi = LWI_TIMEOUT(timeout, timeout_handler);
 117  * rc = l_wait_event(waitq, condition, &lwi);
 118  *
 119  * This form is the same as the first except that it COMPLETELY IGNORES
 120  * SIGNALS.  The caller must therefore beware that if 'timeout' is zero, or if
 121  * 'timeout_handler' is not NULL and returns FALSE, then the ONLY thing that
 122  * can unblock the current process is 'condition' becoming TRUE.
 123  *
 124  * Another form of usage is:
 125  * struct l_wait_info lwi = LWI_TIMEOUT_INTERVAL(timeout, interval,
 126  *                                               timeout_handler);
 127  * rc = l_wait_event(waitq, condition, &lwi);
 128  * This is the same as previous case, but condition is checked once every
 129  * 'interval' jiffies (if non-zero).
 130  *
 131  * Subtle synchronization point: this macro does *not* necessary takes
 132  * wait-queue spin-lock before returning, and, hence, following idiom is safe
 133  * ONLY when caller provides some external locking:
 134  *
 135  *             Thread1                            Thread2
 136  *
 137  *   l_wait_event(&obj->wq, ....);                                       (1)
 138  *
 139  *                                    wake_up(&obj->wq):                 (2)
 140  *                                         spin_lock(&q->lock);          (2.1)
 141  *                                         __wake_up_common(q, ...);     (2.2)
 142  *                                         spin_unlock(&q->lock, flags); (2.3)
 143  *
 144  *   OBD_FREE_PTR(obj);                                                  (3)
 145  *
 146  * As l_wait_event() may "short-cut" execution and return without taking
 147  * wait-queue spin-lock, some additional synchronization is necessary to
 148  * guarantee that step (3) can begin only after (2.3) finishes.
 149  *
 150  * XXX nikita: some ptlrpc daemon threads have races of that sort.
 151  *
 152  */
 153 static inline int back_to_sleep(void *arg)
 154 {
 155         return 0;
 156 }
 157
 158 #define LWI_ON_SIGNAL_NOOP ((void (*)(void *))(-1))
 159
 160 struct l_wait_info {
 161         cfs_duration_t lwi_timeout;
 162         cfs_duration_t lwi_interval;
 163         int            lwi_allow_intr;
 164         int  (*lwi_on_timeout)(void *);
 165         void (*lwi_on_signal)(void *);
 166         void  *lwi_cb_data;
 167 };
 168
 169 /* NB: LWI_TIMEOUT ignores signals completely */
 170 #define LWI_TIMEOUT(time, cb, data)             \
 171 ((struct l_wait_info) {                         \
 172         .lwi_timeout    = time,                 \
 173         .lwi_on_timeout = cb,                   \
 174         .lwi_cb_data    = data,                 \
 175         .lwi_interval   = 0,                    \
 176         .lwi_allow_intr = 0                     \
 177 })
 178
 179 #define LWI_TIMEOUT_INTERVAL(time, interval, cb, data)  \
 180 ((struct l_wait_info) {                                 \
 181         .lwi_timeout    = time,                         \
 182         .lwi_on_timeout = cb,                           \
 183         .lwi_cb_data    = data,                         \
 184         .lwi_interval   = interval,                     \
 185         .lwi_allow_intr = 0                             \
 186 })
 187
 188 #define LWI_TIMEOUT_INTR(time, time_cb, sig_cb, data)   \
 189 ((struct l_wait_info) {                                 \
 190         .lwi_timeout    = time,                         \
 191         .lwi_on_timeout = time_cb,                      \
 192         .lwi_on_signal  = sig_cb,                       \
 193         .lwi_cb_data    = data,                         \
 194         .lwi_interval   = 0,                            \
 195         .lwi_allow_intr = 0                             \
 196 })
 197
 198 #define LWI_TIMEOUT_INTR_ALL(time, time_cb, sig_cb, data)       \
 199 ((struct l_wait_info) {                                         \
 200         .lwi_timeout    = time,                                 \
 201         .lwi_on_timeout = time_cb,                              \
 202         .lwi_on_signal  = sig_cb,                               \
 203         .lwi_cb_data    = data,                                 \
 204         .lwi_interval   = 0,                                    \
 205         .lwi_allow_intr = 1                                     \
 206 })
 207
 208 #define LWI_INTR(cb, data)  LWI_TIMEOUT_INTR(0, NULL, cb, data)
 209
 210 #define LUSTRE_FATAL_SIGS                                        \
 211         (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGTERM) | \
 212          sigmask(SIGQUIT) | sigmask(SIGALRM))
 213
 214 /*
 215  * wait for @condition to become true, but no longer than timeout, specified
 216  * by @info.
 217  */
 218 #define __l_wait_event(wq, condition, info, ret, l_add_wait)                   \
 219 do {                                                                           \
 220         wait_queue_t __wait;                                                   \
 221         cfs_duration_t __timeout = info->lwi_timeout;                          \
 222         sigset_t   __blocked;                                              \
 223         int   __allow_intr = info->lwi_allow_intr;                             \
 224                                                                                \
 225         ret = 0;                                                               \
 226         if (condition)                                                         \
 227                 break;                                                         \
 228                                                                                \
 229         init_waitqueue_entry_current(&__wait);                                 \
 230         l_add_wait(&wq, &__wait);                                              \
 231                                                                                \
 232         /* Block all signals (just the non-fatal ones if no timeout). */       \
 233         if (info->lwi_on_signal != NULL && (__timeout == 0 || __allow_intr))   \
 234                 __blocked = cfs_block_sigsinv(LUSTRE_FATAL_SIGS);              \
 235         else                                                                   \
 236                 __blocked = cfs_block_sigsinv(0);                              \
 237                                                                                \
 238         for (;;) {                                                             \
 239                 unsigned       __wstate;                                       \
 240                                                                                \
 241                 __wstate = info->lwi_on_signal != NULL &&                      \
 242                            (__timeout == 0 || __allow_intr) ?                  \
 243                         TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;             \
 244                                                                                \
 245                 set_current_state(TASK_INTERRUPTIBLE);                         \
 246                                                                                \
 247                 if (condition)                                                 \
 248                         break;                                                 \
 249                                                                                \
 250                 if (__timeout == 0) {                                          \
 251                         waitq_wait(&__wait, __wstate);                         \
 252                 } else {                                                       \
 253                         cfs_duration_t interval = info->lwi_interval?          \
 254                                              min_t(cfs_duration_t,             \
 255                                                  info->lwi_interval,__timeout):\
 256                                              __timeout;                        \
 257                         cfs_duration_t remaining = waitq_timedwait(&__wait,    \
 258                                                    __wstate,                   \
 259                                                    interval);                  \
 260                         __timeout = cfs_time_sub(__timeout,                    \
 261                                             cfs_time_sub(interval, remaining));\
 262                         if (__timeout == 0) {                                  \
 263                                 if (info->lwi_on_timeout == NULL ||            \
 264                                     info->lwi_on_timeout(info->lwi_cb_data)) { \
 265                                         ret = -ETIMEDOUT;                      \
 266                                         break;                                 \
 267                                 }                                              \
 268                                 /* Take signals after the timeout expires. */  \
 269                                 if (info->lwi_on_signal != NULL)               \
 270                                     (void)cfs_block_sigsinv(LUSTRE_FATAL_SIGS);\
 271                         }                                                      \
 272                 }                                                              \
 273                                                                                \
 274                 if (condition)                                                 \
 275                         break;                                                 \
 276                 if (cfs_signal_pending()) {                                    \
 277                         if (info->lwi_on_signal != NULL &&                     \
 278                             (__timeout == 0 || __allow_intr)) {                \
 279                                 if (info->lwi_on_signal != LWI_ON_SIGNAL_NOOP) \
 280                                         info->lwi_on_signal(info->lwi_cb_data);\
 281                                 ret = -EINTR;                                  \
 282                                 break;                                         \
 283                         }                                                      \
 284                         /* We have to do this here because some signals */     \
 285                         /* are not blockable - ie from strace(1).       */     \
 286                         /* In these cases we want to schedule_timeout() */     \
 287                         /* again, because we don't want that to return  */     \
 288                         /* -EINTR when the RPC actually succeeded.      */     \
 289                         /* the recalc_sigpending() below will deliver the */   \
 290                         /* signal properly.                             */     \
 291                         cfs_clear_sigpending();                                \
 292                 }                                                              \
 293         }                                                                      \
 294                                                                                \
 295         cfs_restore_sigs(__blocked);                                           \
 296                                                                                \
 297         set_current_state(TASK_RUNNING);                                       \
 298         remove_wait_queue(&wq, &__wait);                                       \
 299 } while (0)
 300
 301
 302
 303 #define l_wait_event(wq, condition, info)                       \
 304 ({                                                              \
 305         int                 __ret;                              \
 306         struct l_wait_info *__info = (info);                    \
 307                                                                 \
 308         __l_wait_event(wq, condition, __info,                   \
 309                        __ret, add_wait_queue);                  \
 310         __ret;                                                  \
 311 })
 312
 313 #define l_wait_event_exclusive(wq, condition, info)             \
 314 ({                                                              \
 315         int                 __ret;                              \
 316         struct l_wait_info *__info = (info);                    \
 317                                                                 \
 318         __l_wait_event(wq, condition, __info,                   \
 319                        __ret, add_wait_queue_exclusive);        \
 320         __ret;                                                  \
 321 })
 322
 323 #define l_wait_event_exclusive_head(wq, condition, info)        \
 324 ({                                                              \
 325         int                 __ret;                              \
 326         struct l_wait_info *__info = (info);                    \
 327                                                                 \
 328         __l_wait_event(wq, condition, __info,                   \
 329                        __ret, add_wait_queue_exclusive_head);   \
 330         __ret;                                                  \
 331 })
 332
 333 #define l_wait_condition(wq, condition)                         \
 334 ({                                                              \
 335         struct l_wait_info lwi = { 0 };                         \
 336         l_wait_event(wq, condition, &lwi);                      \
 337 })
 338
 339 #define l_wait_condition_exclusive(wq, condition)               \
 340 ({                                                              \
 341         struct l_wait_info lwi = { 0 };                         \
 342         l_wait_event_exclusive(wq, condition, &lwi);            \
 343 })
 344
 345 #define l_wait_condition_exclusive_head(wq, condition)          \
 346 ({                                                              \
 347         struct l_wait_info lwi = { 0 };                         \
 348         l_wait_event_exclusive_head(wq, condition, &lwi);       \
 349 })
 350
 351 /** @} lib */
 352
 353 #endif /* _LUSTRE_LIB_H */