/*- * Copyright (c) 2011, 2012, 2013 Spectra Logic Corporation * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions, and the following disclaimer, * without modification. * 2. Redistributions in binary form must reproduce at minimum a disclaimer * substantially similar to the "NO WARRANTY" disclaimer below * ("Disclaimer") and any redistribution must be conditioned upon * including a substantially similar Disclaimer requirement for further * binary redistribution. * * NO WARRANTY * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGES. * * Authors: Justin T. Gibbs (Spectra Logic Corporation) */ /** * \file case_file.h * * CaseFile objects aggregate vdev faults that may require ZFSD action * in order to maintain the health of a ZFS pool. * * Header requirements: * * #include <list> * * #include "callout.h" * #include "zfsd_event.h" */ #ifndef _CASE_FILE_H_ #define _CASE_FILE_H_ /*=========================== Forward Declarations ===========================*/ class CaseFile; class Vdev; /*============================= Class Definitions ============================*/ /*------------------------------- CaseFileList -------------------------------*/ /** * CaseFileList is a specialization of the standard list STL container. */ typedef std::list< CaseFile *> CaseFileList; /*--------------------------------- CaseFile ---------------------------------*/ /** * A CaseFile object is instantiated anytime a vdev for an active pool * experiences an I/O error, is faulted by ZFS, or is determined to be * missing/removed. * * A vdev may have at most one CaseFile. * * CaseFiles are retired when a vdev leaves an active pool configuration * or an action is taken to resolve the issues recorded in the CaseFile. * * Logging a case against a vdev does not imply that an immediate action * to resolve a fault is required or even desired. For example, a CaseFile * must accumulate a number of I/O errors in order to flag a device as * degraded. * * Vdev I/O errors are not recorded in ZFS label inforamation. For this * reasons, CaseFile%%s with accumulated I/O error events are serialized * to the file system so that they survive across boots. Currently all * other fault types can be reconstructed from ZFS label information, so * CaseFile%%s for missing, faulted, or degradded members are just recreated * at ZFSD startup instead of being deserialized from the file system. */ class CaseFile { public: /** * \brief Find a CaseFile object by a vdev's pool/vdev GUID tuple. * * \param poolGUID Pool GUID for the vdev of the CaseFile to find. * If InvalidGuid, then only match the vdev GUID * instead of both pool and vdev GUIDs. * \param vdevGUID Vdev GUID for the vdev of the CaseFile to find. * * \return If found, a pointer to a valid CaseFile object. * Otherwise NULL. */ static CaseFile *Find(DevdCtl::Guid poolGUID, DevdCtl::Guid vdevGUID); /** * \brief Find multiple CaseFile objects by a vdev's pool/vdev * GUID tuple (special case for spare vdevs) * * \param poolGUID Pool GUID for the vdev of the CaseFile to find. * If InvalidGuid, then only match the vdev GUID * instead of both pool and vdev GUIDs. * \param vdevGUID Vdev GUID for the vdev of the CaseFile to find. * \param caseList List of cases associated with the vdev. */ static void Find(DevdCtl::Guid poolGUID, DevdCtl::Guid vdevGUID, CaseFileList &caseList); /** * \brief Find a CaseFile object by a vdev's current/last known * physical path. * * \param physPath Physical path of the vdev of the CaseFile to find. * * \return If found, a pointer to a valid CaseFile object. * Otherwise NULL. */ static CaseFile *Find(const string &physPath); /** * \brief ReEvaluate all open cases whose pool guid matches the argument * * \param poolGUID Only reevaluate cases for this pool * \param event Try to consume this event with the casefile */ static void ReEvaluateByGuid(DevdCtl::Guid poolGUID, const ZfsEvent &event); /** * \brief Create or return an existing active CaseFile for the * specified vdev. * * \param vdev The vdev object for which to find/create a CaseFile. * * \return A reference to a valid CaseFile object. */ static CaseFile &Create(Vdev &vdev); /** * \brief Deserialize all serialized CaseFile objects found in * the file system. */ static void DeSerialize(); /** * \brief returns true if there are no CaseFiles */ static bool Empty(); /** * \brief Emit syslog data on all active CaseFile%%s in the system. */ static void LogAll(); /** * \brief Destroy the in-core cache of CaseFile data. * * This routine does not disturb the on disk, serialized, CaseFile * data. */ static void PurgeAll(); DevdCtl::Guid PoolGUID() const; DevdCtl::Guid VdevGUID() const; vdev_state VdevState() const; const string &PoolGUIDString() const; const string &VdevGUIDString() const; const string &PhysicalPath() const; /** * \brief Attempt to resolve this CaseFile using the disk * resource at the given device/physical path/vdev object * tuple. * * \param devPath The devfs path for the disk resource. * \param physPath The physical path information reported by * the disk resource. * \param vdev If the disk contains ZFS label information, * a pointer to the disk label's vdev object * data. Otherwise NULL. * * \return True if this event was consumed by this CaseFile. */ bool ReEvaluate(const string &devPath, const string &physPath, Vdev *vdev); /** * \brief Update this CaseFile in light of the provided ZfsEvent. * * Must be virtual so it can be overridden in the unit tests * * \param event The ZfsEvent to evaluate. * * \return True if this event was consumed by this CaseFile. */ virtual bool ReEvaluate(const ZfsEvent &event); /** * \brief Register an itimer callout for the given event, if necessary */ virtual void RegisterCallout(const DevdCtl::Event &event); /** * \brief Close a case if it is no longer relevant. * * This method deals with cases tracking soft errors. Soft errors * will be discarded should a remove event occur within a short period * of the soft errors being reported. We also discard the events * if the vdev is marked degraded or failed. * * \return True if the case is closed. False otherwise. */ bool CloseIfSolved(); /** * \brief Emit data about this CaseFile via syslog(3). */ void Log(); /** * \brief Whether we should degrade this vdev */ bool ShouldDegrade() const; /** * \brief Whether we should fault this vdev */ bool ShouldFault() const; /** * \brief If this vdev is spare */ int IsSpare(); /** * \brief Get case vdev's specified property */ int GetVdevProp(vdev_prop_t) const; protected: enum { /* * Use these defaults if we can't get the corresponding vdev * prop or if the prop is not set */ /** * The number of soft errors on a vdev required * to transition a vdev from healthy to degraded * status */ DEFAULT_ZFS_DEGRADE_IO_COUNT = 50, /** * The number of delay errors on a vdev required to fault it */ DEFAULT_ZFS_FAULT_SLOW_IO_COUNT = 8, }; static CalloutFunc_t OnGracePeriodEnded; /** * \brief scandir(3) filter function used to find files containing * serialized CaseFile data. * * \param dirEntry Directory entry for the file to filter. * * \return Non-zero for a file to include in the selection, * otherwise 0. */ static int DeSerializeSelector(const struct dirent *dirEntry); /** * \brief Given the name of a file containing serialized events from a * CaseFile object, create/update an in-core CaseFile object * representing the serialized data. * * \param fileName The name of a file containing serialized events * from a CaseFile object. */ static void DeSerializeFile(const char *fileName); /** Constructor. */ CaseFile(const Vdev &vdev); /** * Destructor. * Must be virtual so it can be subclassed in the unit tests */ virtual ~CaseFile(); /** * \brief Reload state for the vdev associated with this CaseFile. * * \return True if the refresh was successful. False if the system * has no record of the pool or vdev for this CaseFile. */ virtual bool RefreshVdevState(); /** * \brief Free all events in the m_events list. */ void PurgeEvents(); /** * \brief Free all events in the m_tentativeEvents list. */ void PurgeTentativeEvents(); /** * \brief Commit to file system storage. */ void Serialize(); /** * \brief Retrieve event data from a serialization stream. * * \param caseStream The serializtion stream to parse. */ void DeSerialize(std::ifstream &caseStream); /** * \brief Serializes the supplied event list and writes it to fd * * \param prefix If not NULL, this prefix will be prepended to * every event in the file. */ void SerializeEvList(const DevdCtl::EventList events, int fd, const char* prefix=NULL) const; /** * \brief Unconditionally close a CaseFile. */ virtual void Close(); /** * \brief Callout callback invoked when the remove timer grace * period expires. * * If no remove events are received prior to the grace period * firing, then any tentative events are promoted and counted * against the health of the vdev. */ void OnGracePeriodEnded(); /** * \brief Attempt to activate a spare on this case's pool. * * Call this whenever a pool becomes degraded. It will look for any * spare devices and activate one to replace the casefile's vdev. It * will _not_ close the casefile; that should only happen when the * missing drive is replaced or the user promotes the spare. * * \return True if a spare was activated */ bool ActivateSpare(); /** * \brief replace a pool's vdev with another * * \param vdev_type The type of the new vdev. Usually either * VDEV_TYPE_DISK or VDEV_TYPE_FILE * \param path The file system path to the new vdev * \param isspare Whether the new vdev is a spare * * \return true iff the replacement was successful */ bool Replace(const char* vdev_type, const char* path, bool isspare); /** * \brief Which vdev, if any, is replacing ours. * * \param zhp Pool handle state from the caller context * * \return the vdev that is currently replacing ours, * or NonexistentVdev if there isn't one. */ Vdev BeingReplacedBy(zpool_handle_t *zhp); /** * \brief All CaseFiles being tracked by ZFSD. */ static CaseFileList s_activeCases; /** * \brief The file system path to serialized CaseFile data. */ static const string s_caseFilePath; /** * \brief A list of soft error events counted against the health of * a vdev. */ DevdCtl::EventList m_events; /** * \brief A list of soft error events waiting for a grace period * expiration before being counted against the health of * a vdev. */ DevdCtl::EventList m_tentativeEvents; DevdCtl::Guid m_poolGUID; DevdCtl::Guid m_vdevGUID; vdev_state m_vdevState; string m_poolGUIDString; string m_vdevGUIDString; string m_vdevPhysPath; string m_vdevName; int m_is_spare; /** * \brief Callout activated when a grace period */ Callout m_tentativeTimer; private: nvlist_t *CaseVdev(zpool_handle_t *zhp) const; }; inline DevdCtl::Guid CaseFile::PoolGUID() const { return (m_poolGUID); } inline DevdCtl::Guid CaseFile::VdevGUID() const { return (m_vdevGUID); } inline vdev_state CaseFile::VdevState() const { return (m_vdevState); } inline const string & CaseFile::PoolGUIDString() const { return (m_poolGUIDString); } inline const string & CaseFile::VdevGUIDString() const { return (m_vdevGUIDString); } inline const string & CaseFile::PhysicalPath() const { return (m_vdevPhysPath); } #endif /* _CASE_FILE_H_ */
