src/vol/volume_inline.h

   1 /*
   2  * Copyright 2005-2008, Sine Nomine Associates and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 #ifndef _AFS_VOL_VOLUME_INLINE_H
  11 #define _AFS_VOL_VOLUME_INLINE_H 1
  12
  13 #include "volume.h"
  14 #include "partition.h"
  15
  16 #ifdef AFS_DEMAND_ATTACH_FS
  17 # include "lock.h"
  18 #endif
  19
  20 #ifdef AFS_PTHREAD_ENV
  21
  22 #include <afs/opr_assert.h>
  23
  24 /**
  25  * @param[in] cv cond var
  26  * @param[in] ts deadline, or NULL to wait forever
  27  * @param[out] timedout  set to 1 if we returned due to the deadline, 0 if we
  28  *                       returned due to the cond var getting signalled. If
  29  *                       NULL, it is ignored.
  30  */
  31 static_inline void
  32 VOL_CV_TIMEDWAIT(pthread_cond_t *cv, const struct timespec *ts, int *timedout)
  33 {
  34     int code;
  35     if (timedout) {
  36         *timedout = 0;
  37     }
  38     if (!ts) {
  39         VOL_CV_WAIT(cv);
  40         return;
  41     }
  42     VOL_LOCK_DBG_CV_WAIT_BEGIN;
  43     code = opr_cv_timedwait(cv, &vol_glock_mutex, ts);
  44     VOL_LOCK_DBG_CV_WAIT_END;
  45     if (code == ETIMEDOUT) {
  46         code = 0;
  47         if (timedout) {
  48             *timedout = 1;
  49         }
  50     }
  51     opr_Assert(code == 0);
  52 }
  53 #endif /* AFS_PTHREAD_ENV */
  54
  55 /**
  56  * tell caller whether the given program type represents a salvaging
  57  * program.
  58  *
  59  * @param type  program type enumeration
  60  *
  61  * @return whether program state is a salvager
  62  *   @retval 0  type is a non-salvaging program
  63  *   @retval 1  type is a salvaging program
  64  */
  65 static_inline int
  66 VIsSalvager(ProgramType type)
  67 {
  68     switch(type) {
  69     case salvager:
  70     case salvageServer:
  71     case volumeSalvager:
  72         return 1;
  73     default:
  74         return 0;
  75     }
  76 }
  77
  78 /**
  79  * tells caller whether or not we need to lock the entire partition when
  80  * attaching a volume.
  81  *
  82  * @return whether or not we need to lock the partition
  83  *  @retval 0  no, we do not
  84  *  @retval 1  yes, we do
  85  *
  86  * @note for DAFS, always returns 0, since we use per-header locks instead
  87  */
  88 static_inline int
  89 VRequiresPartLock(void)
  90 {
  91 #ifdef AFS_DEMAND_ATTACH_FS
  92     return 0;
  93 #else
  94     switch (programType) {
  95     case volumeServer:
  96     case volumeUtility:
  97         return 1;
  98     default:
  99         return 0;
 100     }
 101 #endif /* AFS_DEMAND_ATTACH_FS */
 102 }
 103
 104 /**
 105  * tells caller whether or not we need to check out a volume from the
 106  * fileserver before we can use it.
 107  *
 108  * @param[in] mode the mode of attachment for the volume
 109  *
 110  * @return whether or not we need to check out the volume from the fileserver
 111  *  @retval 0 no, we can just use the volume
 112  *  @retval 1 yes, we must check out the volume before use
 113  */
 114 static_inline int
 115 VMustCheckoutVolume(int mode)
 116 {
 117     if (VCanUseFSSYNC() && mode != V_SECRETLY && mode != V_PEEK) {
 118         return 1;
 119     }
 120     return 0;
 121 }
 122
 123 /**
 124  * tells caller whether we should check the inUse field in the volume
 125  * header when attaching a volume.
 126  *
 127  * If we check inUse, that generally means we will salvage the volume
 128  * (or put it in an error state) if we detect that another program
 129  * claims to be using the volume when we try to attach. We don't always
 130  * want to do that, since sometimes we know that the volume may be in
 131  * use by another program, e.g. when we are attaching with V_PEEK
 132  * or attaching for only reading (V_READONLY).
 133  *
 134  * @param mode  the mode of attachment for the volume
 135  *
 136  * @return whether or not we should check inUse
 137  *  @retval 0  no, we should not check inUse
 138  *  @retval 1  yes, we should check inUse
 139  */
 140 static_inline int
 141 VShouldCheckInUse(int mode)
 142 {
 143     if (VCanUnsafeAttach()) {
 144         return 0;
 145     }
 146     if (programType == fileServer) {
 147        return 1;
 148     }
 149     if (VMustCheckoutVolume(mode)) {
 150         /*
 151          * Before VShouldCheckInUse() was called, the caller checked out the
 152          * volume from the fileserver. The volume may not be in use by the
 153          * fileserver, or another program, at this point. The caller should
 154          * verify by checking inUse is not set, otherwise the volume state
 155          * is in error.
 156          *
 157          * However, an exception is made for the V_READONLY attach mode.  The
 158          * volume may still be in use by the fileserver when a caller has
 159          * checked out the volume from the fileserver with the V_READONLY
 160          * attach mode, and so it is not an error for the inUse field to be set
 161          * at this point. The caller should not check the inUse and may
 162          * not change any volume state.
 163          */
 164         if (mode == V_READONLY) {
 165             return 0; /* allowed to be inUse; do not check */
 166         }
 167         return 1; /* may not be inUse; check */
 168     }
 169     return 0;
 170 }
 171
 172 #ifdef AFS_DEMAND_ATTACH_FS
 173 /**
 174  * acquire a non-blocking disk lock for a particular volume id.
 175  *
 176  * @param[in] volid the volume ID to lock
 177  * @param[in] dp    the partition on which 'volid' resides
 178  * @param[in] locktype READ_LOCK or WRITE_LOCK
 179  *
 180  * @return operation status
 181  *  @retval 0 success, lock was obtained
 182  *  @retval EBUSY another process holds a conflicting lock
 183  *  @retval EIO   error acquiring lock
 184  *
 185  * @note Use VLockVolumeNB instead, if possible; only use this directly if
 186  * you are not dealing with 'Volume*'s and attached volumes and such
 187  *
 188  * @pre There must not be any other threads acquiring locks on the same volid
 189  * and partition; the locks will not work correctly if two threads try to
 190  * acquire locks for the same volume
 191  */
 192 static_inline int
 193 VLockVolumeByIdNB(VolumeId volid, struct DiskPartition64 *dp, int locktype)
 194 {
 195     return VLockFileLock(&dp->volLockFile, volid, locktype, 1 /* nonblock */);
 196 }
 197
 198 /**
 199  * release a lock acquired by VLockVolumeByIdNB.
 200  *
 201  * @param[in] volid the volume id to unlock
 202  * @param[in] dp    the partition on which 'volid' resides
 203  *
 204  * @pre volid was previously locked by VLockVolumeByIdNB
 205  */
 206 static_inline void
 207 VUnlockVolumeById(VolumeId volid, struct DiskPartition64 *dp)
 208 {
 209     VLockFileUnlock(&dp->volLockFile, volid);
 210 }
 211
 212 /***************************************************/
 213 /* demand attach fs state machine routines         */
 214 /***************************************************/
 215
 216 /**
 217  * tells caller whether we need to keep volumes locked for the entire time we
 218  * are using them, or if we can unlock volumes as soon as they are attached.
 219  *
 220  * @return whether we can unlock attached volumes or not
 221  *  @retval 1 yes, we can unlock attached volumes
 222  *  @retval 0 no, do not unlock volumes until we unattach them
 223  */
 224 static_inline int
 225 VCanUnlockAttached(void)
 226 {
 227     switch(programType) {
 228     case fileServer:
 229         return 1;
 230     default:
 231         return 0;
 232     }
 233 }
 234
 235 /**
 236  * tells caller whether we need to lock a vol header with a write lock, a
 237  * read lock, or if we do not need to lock it at all, when attaching.
 238  *
 239  * @param[in]  mode  volume attachment mode
 240  * @param[in]  writable  1 if the volume is writable, 0 if not
 241  *
 242  * @return how we need to lock the vol header
 243  *  @retval 0 do not lock the vol header at all
 244  *  @retval READ_LOCK lock the vol header with a read lock
 245  *  @retval WRITE_LOCK lock the vol header with a write lock
 246  *
 247  * @note DAFS only (non-DAFS uses partition locks)
 248  */
 249 static_inline int
 250 VVolLockType(int mode, int writable)
 251 {
 252     switch (programType) {
 253     case fileServer:
 254         if (writable) {
 255             return WRITE_LOCK;
 256         }
 257         return READ_LOCK;
 258
 259     case volumeSalvager:
 260     case salvageServer:
 261     case salvager:
 262         return WRITE_LOCK;
 263
 264     default:
 265         /* volserver, vol utilies, etc */
 266
 267         switch (mode) {
 268         case V_READONLY:
 269             return READ_LOCK;
 270
 271         case V_VOLUPD:
 272         case V_SECRETLY:
 273             return WRITE_LOCK;
 274
 275         case V_CLONE:
 276         case V_DUMP:
 277             if (writable) {
 278                 return WRITE_LOCK;
 279             }
 280             return READ_LOCK;
 281
 282         case V_PEEK:
 283             return 0;
 284
 285         default:
 286             opr_Assert(0 /* unknown checkout mode */);
 287             return 0;
 288         }
 289     }
 290 }
 291
 292 /**
 293  * tells caller whether or not the volume is effectively salvaging.
 294  *
 295  * @param vp  volume pointer
 296  *
 297  * @return whether volume is salvaging or not
 298  *  @retval 0 no, volume is not salvaging
 299  *  @retval 1 yes, volume is salvaging
 300  *
 301  * @note The volume may not actually be getting salvaged at the moment if
 302  *       this returns 1, but may have just been requested or scheduled to be
 303  *       salvaged. Callers should treat these cases as pretty much the same
 304  *       anyway, since we should not touch a volume that is busy salvaging or
 305  *       waiting to be salvaged.
 306  */
 307 static_inline int
 308 VIsSalvaging(struct Volume *vp)
 309 {
 310     /* these tests are a bit redundant, but to be safe... */
 311     switch(V_attachState(vp)) {
 312     case VOL_STATE_SALVAGING:
 313     case VOL_STATE_SALVAGE_REQ:
 314         return 1;
 315     default:
 316         if (vp->salvage.requested || vp->salvage.scheduled) {
 317             return 1;
 318         }
 319     }
 320     return 0;
 321 }
 322
 323 /**
 324  * tells caller whether or not the current state requires
 325  * exclusive access without holding glock.
 326  *
 327  * @param state  volume state enumeration
 328  *
 329  * @return whether volume state is a mutually exclusive state
 330  *   @retval 0  no, state is re-entrant
 331  *   @retval 1  yes, state is mutually exclusive
 332  *
 333  * @note DEMAND_ATTACH_FS only
 334  */
 335 static_inline int
 336 VIsExclusiveState(VolState state)
 337 {
 338     switch (state) {
 339     case VOL_STATE_UPDATING:
 340     case VOL_STATE_ATTACHING:
 341     case VOL_STATE_GET_BITMAP:
 342     case VOL_STATE_HDR_LOADING:
 343     case VOL_STATE_HDR_ATTACHING:
 344     case VOL_STATE_OFFLINING:
 345     case VOL_STATE_DETACHING:
 346     case VOL_STATE_SALVSYNC_REQ:
 347     case VOL_STATE_VNODE_ALLOC:
 348     case VOL_STATE_VNODE_GET:
 349     case VOL_STATE_VNODE_CLOSE:
 350     case VOL_STATE_VNODE_RELEASE:
 351     case VOL_STATE_VLRU_ADD:
 352     case VOL_STATE_SCANNING_RXCALLS:
 353         return 1;
 354     default:
 355         return 0;
 356     }
 357 }
 358
 359 /**
 360  * tell caller whether V_attachState is an error condition.
 361  *
 362  * @param state  volume state enumeration
 363  *
 364  * @return whether volume state is in error state
 365  *   @retval 0  state is not an error state
 366  *   @retval 1  state is an error state
 367  *
 368  * @note DEMAND_ATTACH_FS only
 369  */
 370 static_inline int
 371 VIsErrorState(VolState state)
 372 {
 373     switch (state) {
 374     case VOL_STATE_ERROR:
 375     case VOL_STATE_SALVAGING:
 376     case VOL_STATE_SALVAGE_REQ:
 377         return 1;
 378     default:
 379         return 0;
 380     }
 381 }
 382
 383 /**
 384  * tell caller whether V_attachState is an offline condition.
 385  *
 386  * @param state  volume state enumeration
 387  *
 388  * @return whether volume state is in offline state
 389  *   @retval 0  state is not an offline state
 390  *   @retval 1  state is an offline state
 391  *
 392  * @note DEMAND_ATTACH_FS only
 393  */
 394 static_inline int
 395 VIsOfflineState(VolState state)
 396 {
 397     switch (state) {
 398     case VOL_STATE_UNATTACHED:
 399     case VOL_STATE_ERROR:
 400     case VOL_STATE_SALVAGING:
 401     case VOL_STATE_DELETED:
 402         return 1;
 403     default:
 404         return 0;
 405     }
 406 }
 407
 408 /**
 409  * tell caller whether V_attachState is valid.
 410  *
 411  * @param state  volume state enumeration
 412  *
 413  * @return whether volume state is a mutually exclusive state
 414  *   @retval 0  no, state is not valid
 415  *   @retval 1  yes, state is a valid enumeration member
 416  *
 417  * @note DEMAND_ATTACH_FS only
 418  *
 419  * @note do we really want to treat VOL_STATE_FREED as valid?
 420  */
 421 static_inline int
 422 VIsValidState(VolState state)
 423 {
 424     if (((int) state >= 0) &&
 425         (state < VOL_STATE_COUNT)) {
 426         return 1;
 427     }
 428     return 0;
 429 }
 430
 431 /**
 432  * increment volume-package internal refcount.
 433  *
 434  * @param vp  volume object pointer
 435  *
 436  * @internal volume package internal use only
 437  *
 438  * @pre VOL_LOCK must be held
 439  *
 440  * @post volume waiters refcount is incremented
 441  *
 442  * @see VCancelReservation_r
 443  *
 444  * @note DEMAND_ATTACH_FS only
 445  */
 446 static_inline void
 447 VCreateReservation_r(Volume * vp)
 448 {
 449     vp->nWaiters++;
 450 }
 451
 452 /**
 453  * wait for the volume to change states.
 454  *
 455  * @param vp  volume object pointer
 456  *
 457  * @pre VOL_LOCK held; ref held on volume
 458  *
 459  * @post VOL_LOCK held; volume state has changed from previous value
 460  *
 461  * @note DEMAND_ATTACH_FS only
 462  */
 463 static_inline void
 464 VWaitStateChange_r(Volume * vp)
 465 {
 466     VolState state_save = V_attachState(vp);
 467
 468     opr_Assert(vp->nWaiters || vp->nUsers);
 469     do {
 470         VOL_CV_WAIT(&V_attachCV(vp));
 471     } while (V_attachState(vp) == state_save);
 472     opr_Assert(V_attachState(vp) != VOL_STATE_FREED);
 473 }
 474
 475 /**
 476  * wait for the volume to change states within a certain amount of time
 477  *
 478  * @param[in] vp  volume object pointer
 479  * @param[in] ts  deadline (absolute time) or NULL to wait forever
 480  *
 481  * @pre VOL_LOCK held; ref held on volume
 482  * @post VOL_LOCK held; volume state has changed and/or it is after the time
 483  *       specified in ts
 484  *
 485  * @note DEMAND_ATTACH_FS only
 486  * @note if ts is NULL, this is identical to VWaitStateChange_r
 487  */
 488 static_inline void
 489 VTimedWaitStateChange_r(Volume * vp, const struct timespec *ts, int *atimedout)
 490 {
 491     VolState state_save;
 492     int timeout;
 493
 494     if (atimedout) {
 495         *atimedout = 0;
 496     }
 497
 498     if (!ts) {
 499         VWaitStateChange_r(vp);
 500         return;
 501     }
 502
 503     state_save = V_attachState(vp);
 504
 505     opr_Assert(vp->nWaiters || vp->nUsers);
 506     do {
 507         VOL_CV_TIMEDWAIT(&V_attachCV(vp), ts, &timeout);
 508     } while (V_attachState(vp) == state_save && !timeout);
 509     opr_Assert(V_attachState(vp) != VOL_STATE_FREED);
 510
 511     if (atimedout && timeout) {
 512         *atimedout = 1;
 513     }
 514 }
 515
 516 /**
 517  * wait for blocking ops to end.
 518  *
 519  * @pre VOL_LOCK held; ref held on volume
 520  *
 521  * @post VOL_LOCK held; volume not in exclusive state
 522  *
 523  * @param vp  volume object pointer
 524  *
 525  * @note DEMAND_ATTACH_FS only
 526  */
 527 static_inline void
 528 VWaitExclusiveState_r(Volume * vp)
 529 {
 530     opr_Assert(vp->nWaiters || vp->nUsers);
 531     while (VIsExclusiveState(V_attachState(vp))) {
 532         VOL_CV_WAIT(&V_attachCV(vp));
 533     }
 534     opr_Assert(V_attachState(vp) != VOL_STATE_FREED);
 535 }
 536
 537 /**
 538  * change state, and notify other threads,
 539  * return previous state to caller.
 540  *
 541  * @param vp         pointer to volume object
 542  * @param new_state  new volume state value
 543  * @pre VOL_LOCK held
 544  *
 545  * @post volume state changed; stats updated
 546  *
 547  * @return previous volume state
 548  *
 549  * @note DEMAND_ATTACH_FS only
 550  */
 551 static_inline VolState
 552 VChangeState_r(Volume * vp, VolState new_state)
 553 {
 554     VolState old_state = V_attachState(vp);
 555
 556     /* XXX profiling need to make sure these counters
 557      * don't kill performance... */
 558     VStats.state_levels[old_state]--;
 559     VStats.state_levels[new_state]++;
 560
 561     V_attachState(vp) = new_state;
 562     opr_cv_broadcast(&V_attachCV(vp));
 563     return old_state;
 564 }
 565
 566 #endif /* AFS_DEMAND_ATTACH_FS */
 567
 568 #define VENUMCASE(en) \
 569     case en: return #en
 570
 571 /**
 572  * translate a ProgramType code to a string.
 573  *
 574  * @param[in] type ProgramType numeric code
 575  *
 576  * @return a human-readable string for that program type
 577  *  @retval "**UNKNOWN**" an unknown ProgramType was given
 578  */
 579 static_inline char *
 580 VPTypeToString(ProgramType type)
 581 {
 582     switch (type) {
 583         VENUMCASE(fileServer);
 584         VENUMCASE(volumeUtility);
 585         VENUMCASE(salvager);
 586         VENUMCASE(salvageServer);
 587         VENUMCASE(debugUtility);
 588         VENUMCASE(volumeServer);
 589         VENUMCASE(volumeSalvager);
 590     default:
 591         return "**UNKNOWN**";
 592     }
 593 }
 594
 595 #undef VENUMCASE
 596
 597 #endif /* _AFS_VOL_VOLUME_INLINE_H */