1 /*- 2 * Copyright (c) 2011, 2012, 2013 Spectra Logic Corporation 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions, and the following disclaimer, 10 * without modification. 11 * 2. Redistributions in binary form must reproduce at minimum a disclaimer 12 * substantially similar to the "NO WARRANTY" disclaimer below 13 * ("Disclaimer") and any redistribution must be conditioned upon 14 * including a substantially similar Disclaimer requirement for further 15 * binary redistribution. 16 * 17 * NO WARRANTY 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 26 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 27 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGES. 29 * 30 * Authors: Justin T. Gibbs (Spectra Logic Corporation) 31 */ 32 33 /** 34 * \file case_file.h 35 * 36 * CaseFile objects aggregate vdev faults that may require ZFSD action 37 * in order to maintain the health of a ZFS pool. 38 * 39 * Header requirements: 40 * 41 * #include <list> 42 * 43 * #include "callout.h" 44 * #include "zfsd_event.h" 45 */ 46 #ifndef _CASE_FILE_H_ 47 #define _CASE_FILE_H_ 48 49 /*=========================== Forward Declarations ===========================*/ 50 class CaseFile; 51 class Vdev; 52 53 /*============================= Class Definitions ============================*/ 54 /*------------------------------- CaseFileList -------------------------------*/ 55 /** 56 * CaseFileList is a specialization of the standard list STL container. 57 */ 58 typedef std::list< CaseFile *> CaseFileList; 59 60 /*--------------------------------- CaseFile ---------------------------------*/ 61 /** 62 * A CaseFile object is instantiated anytime a vdev for an active pool 63 * experiences an I/O error, is faulted by ZFS, or is determined to be 64 * missing/removed. 65 * 66 * A vdev may have at most one CaseFile. 67 * 68 * CaseFiles are retired when a vdev leaves an active pool configuration 69 * or an action is taken to resolve the issues recorded in the CaseFile. 70 * 71 * Logging a case against a vdev does not imply that an immediate action 72 * to resolve a fault is required or even desired. For example, a CaseFile 73 * must accumulate a number of I/O errors in order to flag a device as 74 * degraded. 75 * 76 * Vdev I/O errors are not recorded in ZFS label inforamation. For this 77 * reasons, CaseFile%%s with accumulated I/O error events are serialized 78 * to the file system so that they survive across boots. Currently all 79 * other fault types can be reconstructed from ZFS label information, so 80 * CaseFile%%s for missing, faulted, or degradded members are just recreated 81 * at ZFSD startup instead of being deserialized from the file system. 82 */ 83 class CaseFile 84 { 85 public: 86 /** 87 * \brief Find a CaseFile object by a vdev's pool/vdev GUID tuple. 88 * 89 * \param poolGUID Pool GUID for the vdev of the CaseFile to find. 90 * If InvalidGuid, then only match the vdev GUID 91 * instead of both pool and vdev GUIDs. 92 * \param vdevGUID Vdev GUID for the vdev of the CaseFile to find. 93 * 94 * \return If found, a pointer to a valid CaseFile object. 95 * Otherwise NULL. 96 */ 97 static CaseFile *Find(DevdCtl::Guid poolGUID, DevdCtl::Guid vdevGUID); 98 99 /** 100 * \brief Find multiple CaseFile objects by a vdev's pool/vdev 101 * GUID tuple (special case for spare vdevs) 102 * 103 * \param poolGUID Pool GUID for the vdev of the CaseFile to find. 104 * If InvalidGuid, then only match the vdev GUID 105 * instead of both pool and vdev GUIDs. 106 * \param vdevGUID Vdev GUID for the vdev of the CaseFile to find. 107 * \param caseList List of cases associated with the vdev. 108 */ 109 static void Find(DevdCtl::Guid poolGUID, DevdCtl::Guid vdevGUID, 110 CaseFileList &caseList); 111 112 /** 113 * \brief Find a CaseFile object by a vdev's current/last known 114 * physical path. 115 * 116 * \param physPath Physical path of the vdev of the CaseFile to find. 117 * 118 * \return If found, a pointer to a valid CaseFile object. 119 * Otherwise NULL. 120 */ 121 static CaseFile *Find(const string &physPath); 122 123 /** 124 * \brief ReEvaluate all open cases whose pool guid matches the argument 125 * 126 * \param poolGUID Only reevaluate cases for this pool 127 * \param event Try to consume this event with the casefile 128 */ 129 static void ReEvaluateByGuid(DevdCtl::Guid poolGUID, 130 const ZfsEvent &event); 131 132 /** 133 * \brief Create or return an existing active CaseFile for the 134 * specified vdev. 135 * 136 * \param vdev The vdev object for which to find/create a CaseFile. 137 * 138 * \return A reference to a valid CaseFile object. 139 */ 140 static CaseFile &Create(Vdev &vdev); 141 142 /** 143 * \brief Deserialize all serialized CaseFile objects found in 144 * the file system. 145 */ 146 static void DeSerialize(); 147 148 /** 149 * \brief returns true if there are no CaseFiles 150 */ 151 static bool Empty(); 152 153 /** 154 * \brief Emit syslog data on all active CaseFile%%s in the system. 155 */ 156 static void LogAll(); 157 158 /** 159 * \brief Destroy the in-core cache of CaseFile data. 160 * 161 * This routine does not disturb the on disk, serialized, CaseFile 162 * data. 163 */ 164 static void PurgeAll(); 165 166 DevdCtl::Guid PoolGUID() const; 167 DevdCtl::Guid VdevGUID() const; 168 vdev_state VdevState() const; 169 const string &PoolGUIDString() const; 170 const string &VdevGUIDString() const; 171 const string &PhysicalPath() const; 172 173 /** 174 * \brief Attempt to resolve this CaseFile using the disk 175 * resource at the given device/physical path/vdev object 176 * tuple. 177 * 178 * \param devPath The devfs path for the disk resource. 179 * \param physPath The physical path information reported by 180 * the disk resource. 181 * \param vdev If the disk contains ZFS label information, 182 * a pointer to the disk label's vdev object 183 * data. Otherwise NULL. 184 * 185 * \return True if this event was consumed by this CaseFile. 186 */ 187 bool ReEvaluate(const string &devPath, const string &physPath, 188 Vdev *vdev); 189 190 /** 191 * \brief Update this CaseFile in light of the provided ZfsEvent. 192 * 193 * Must be virtual so it can be overridden in the unit tests 194 * 195 * \param event The ZfsEvent to evaluate. 196 * 197 * \return True if this event was consumed by this CaseFile. 198 */ 199 virtual bool ReEvaluate(const ZfsEvent &event); 200 201 /** 202 * \brief Register an itimer callout for the given event, if necessary 203 */ 204 virtual void RegisterCallout(const DevdCtl::Event &event); 205 206 /** 207 * \brief Close a case if it is no longer relevant. 208 * 209 * This method deals with cases tracking soft errors. Soft errors 210 * will be discarded should a remove event occur within a short period 211 * of the soft errors being reported. We also discard the events 212 * if the vdev is marked degraded or failed. 213 * 214 * \return True if the case is closed. False otherwise. 215 */ 216 bool CloseIfSolved(); 217 218 /** 219 * \brief Emit data about this CaseFile via syslog(3). 220 */ 221 void Log(); 222 223 /** 224 * \brief Whether we should degrade this vdev 225 */ 226 bool ShouldDegrade() const; 227 228 /** 229 * \brief Whether we should fault this vdev 230 */ 231 bool ShouldFault() const; 232 233 /** 234 * \brief If this vdev is spare 235 */ 236 int IsSpare(); 237 238 protected: 239 enum { 240 /** 241 * The number of soft errors on a vdev required 242 * to transition a vdev from healthy to degraded 243 * status. 244 */ 245 ZFS_DEGRADE_IO_COUNT = 50, 246 /** 247 * The number of delay errors on a vdev required to fault it 248 */ 249 ZFS_FAULT_DELAY_COUNT = 8, 250 }; 251 252 static CalloutFunc_t OnGracePeriodEnded; 253 254 /** 255 * \brief scandir(3) filter function used to find files containing 256 * serialized CaseFile data. 257 * 258 * \param dirEntry Directory entry for the file to filter. 259 * 260 * \return Non-zero for a file to include in the selection, 261 * otherwise 0. 262 */ 263 static int DeSerializeSelector(const struct dirent *dirEntry); 264 265 /** 266 * \brief Given the name of a file containing serialized events from a 267 * CaseFile object, create/update an in-core CaseFile object 268 * representing the serialized data. 269 * 270 * \param fileName The name of a file containing serialized events 271 * from a CaseFile object. 272 */ 273 static void DeSerializeFile(const char *fileName); 274 275 /** Constructor. */ 276 CaseFile(const Vdev &vdev); 277 278 /** 279 * Destructor. 280 * Must be virtual so it can be subclassed in the unit tests 281 */ 282 virtual ~CaseFile(); 283 284 /** 285 * \brief Reload state for the vdev associated with this CaseFile. 286 * 287 * \return True if the refresh was successful. False if the system 288 * has no record of the pool or vdev for this CaseFile. 289 */ 290 virtual bool RefreshVdevState(); 291 292 /** 293 * \brief Free all events in the m_events list. 294 */ 295 void PurgeEvents(); 296 297 /** 298 * \brief Free all events in the m_tentativeEvents list. 299 */ 300 void PurgeTentativeEvents(); 301 302 /** 303 * \brief Commit to file system storage. 304 */ 305 void Serialize(); 306 307 /** 308 * \brief Retrieve event data from a serialization stream. 309 * 310 * \param caseStream The serializtion stream to parse. 311 */ 312 void DeSerialize(std::ifstream &caseStream); 313 314 /** 315 * \brief Serializes the supplied event list and writes it to fd 316 * 317 * \param prefix If not NULL, this prefix will be prepended to 318 * every event in the file. 319 */ 320 void SerializeEvList(const DevdCtl::EventList events, int fd, 321 const char* prefix=NULL) const; 322 323 /** 324 * \brief Unconditionally close a CaseFile. 325 */ 326 virtual void Close(); 327 328 /** 329 * \brief Callout callback invoked when the remove timer grace 330 * period expires. 331 * 332 * If no remove events are received prior to the grace period 333 * firing, then any tentative events are promoted and counted 334 * against the health of the vdev. 335 */ 336 void OnGracePeriodEnded(); 337 338 /** 339 * \brief Attempt to activate a spare on this case's pool. 340 * 341 * Call this whenever a pool becomes degraded. It will look for any 342 * spare devices and activate one to replace the casefile's vdev. It 343 * will _not_ close the casefile; that should only happen when the 344 * missing drive is replaced or the user promotes the spare. 345 * 346 * \return True if a spare was activated 347 */ 348 bool ActivateSpare(); 349 350 /** 351 * \brief replace a pool's vdev with another 352 * 353 * \param vdev_type The type of the new vdev. Usually either 354 * VDEV_TYPE_DISK or VDEV_TYPE_FILE 355 * \param path The file system path to the new vdev 356 * \param isspare Whether the new vdev is a spare 357 * 358 * \return true iff the replacement was successful 359 */ 360 bool Replace(const char* vdev_type, const char* path, bool isspare); 361 362 /** 363 * \brief Which vdev, if any, is replacing ours. 364 * 365 * \param zhp Pool handle state from the caller context 366 * 367 * \return the vdev that is currently replacing ours, 368 * or NonexistentVdev if there isn't one. 369 */ 370 Vdev BeingReplacedBy(zpool_handle_t *zhp); 371 372 /** 373 * \brief All CaseFiles being tracked by ZFSD. 374 */ 375 static CaseFileList s_activeCases; 376 377 /** 378 * \brief The file system path to serialized CaseFile data. 379 */ 380 static const string s_caseFilePath; 381 382 /** 383 * \brief The time ZFSD waits before promoting a tentative event 384 * into a permanent event. 385 */ 386 static const timeval s_removeGracePeriod; 387 388 /** 389 * \brief A list of soft error events counted against the health of 390 * a vdev. 391 */ 392 DevdCtl::EventList m_events; 393 394 /** 395 * \brief A list of soft error events waiting for a grace period 396 * expiration before being counted against the health of 397 * a vdev. 398 */ 399 DevdCtl::EventList m_tentativeEvents; 400 401 DevdCtl::Guid m_poolGUID; 402 DevdCtl::Guid m_vdevGUID; 403 vdev_state m_vdevState; 404 string m_poolGUIDString; 405 string m_vdevGUIDString; 406 string m_vdevPhysPath; 407 int m_is_spare; 408 409 /** 410 * \brief Callout activated when a grace period 411 */ 412 Callout m_tentativeTimer; 413 414 private: 415 nvlist_t *CaseVdev(zpool_handle_t *zhp) const; 416 }; 417 418 inline DevdCtl::Guid 419 CaseFile::PoolGUID() const 420 { 421 return (m_poolGUID); 422 } 423 424 inline DevdCtl::Guid 425 CaseFile::VdevGUID() const 426 { 427 return (m_vdevGUID); 428 } 429 430 inline vdev_state 431 CaseFile::VdevState() const 432 { 433 return (m_vdevState); 434 } 435 436 inline const string & 437 CaseFile::PoolGUIDString() const 438 { 439 return (m_poolGUIDString); 440 } 441 442 inline const string & 443 CaseFile::VdevGUIDString() const 444 { 445 return (m_vdevGUIDString); 446 } 447 448 inline const string & 449 CaseFile::PhysicalPath() const 450 { 451 return (m_vdevPhysPath); 452 } 453 454 #endif /* _CASE_FILE_H_ */ 455