732 lines
25 KiB
C
732 lines
25 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (c) 2017 by Lawrence Livermore National Security, LLC.
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*/
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#include <sys/abd.h>
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#include <sys/mmp.h>
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#include <sys/spa.h>
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#include <sys/spa_impl.h>
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#include <sys/time.h>
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#include <sys/vdev.h>
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#include <sys/vdev_impl.h>
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#include <sys/zfs_context.h>
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#include <sys/callb.h>
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/*
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* Multi-Modifier Protection (MMP) attempts to prevent a user from importing
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* or opening a pool on more than one host at a time. In particular, it
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* prevents "zpool import -f" on a host from succeeding while the pool is
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* already imported on another host. There are many other ways in which a
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* device could be used by two hosts for different purposes at the same time
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* resulting in pool damage. This implementation does not attempt to detect
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* those cases.
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*
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* MMP operates by ensuring there are frequent visible changes on disk (a
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* "heartbeat") at all times. And by altering the import process to check
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* for these changes and failing the import when they are detected. This
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* functionality is enabled by setting the 'multihost' pool property to on.
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*
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* Uberblocks written by the txg_sync thread always go into the first
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* (N-MMP_BLOCKS_PER_LABEL) slots, the remaining slots are reserved for MMP.
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* They are used to hold uberblocks which are exactly the same as the last
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* synced uberblock except that the ub_timestamp and mmp_config are frequently
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* updated. Like all other uberblocks, the slot is written with an embedded
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* checksum, and slots with invalid checksums are ignored. This provides the
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* "heartbeat", with no risk of overwriting good uberblocks that must be
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* preserved, e.g. previous txgs and associated block pointers.
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*
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* Three optional fields are added to uberblock structure; ub_mmp_magic,
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* ub_mmp_config, and ub_mmp_delay. The ub_mmp_magic value allows zfs to tell
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* whether the other ub_mmp_* fields are valid. The ub_mmp_config field tells
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* the importing host the settings of zfs_multihost_interval and
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* zfs_multihost_fail_intervals on the host which last had (or currently has)
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* the pool imported. These determine how long a host must wait to detect
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* activity in the pool, before concluding the pool is not in use. The
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* mmp_delay field is a decaying average of the amount of time between
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* completion of successive MMP writes, in nanoseconds. It indicates whether
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* MMP is enabled.
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*
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* During import an activity test may now be performed to determine if
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* the pool is in use. The activity test is typically required if the
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* ZPOOL_CONFIG_HOSTID does not match the system hostid, the pool state is
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* POOL_STATE_ACTIVE, and the pool is not a root pool.
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*
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* The activity test finds the "best" uberblock (highest txg, timestamp, and, if
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* ub_mmp_magic is valid, sequence number from ub_mmp_config). It then waits
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* some time, and finds the "best" uberblock again. If any of the mentioned
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* fields have different values in the newly read uberblock, the pool is in use
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* by another host and the import fails. In order to assure the accuracy of the
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* activity test, the default values result in an activity test duration of 20x
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* the mmp write interval.
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*
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* The duration of the "zpool import" activity test depends on the information
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* available in the "best" uberblock:
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*
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* 1) If uberblock was written by zfs-0.8 or newer and fail_intervals > 0:
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* ub_mmp_config.fail_intervals * ub_mmp_config.multihost_interval * 2
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*
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* In this case, a weak guarantee is provided. Since the host which last had
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* the pool imported will suspend the pool if no mmp writes land within
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* fail_intervals * multihost_interval ms, the absence of writes during that
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* time means either the pool is not imported, or it is imported but the pool
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* is suspended and no further writes will occur.
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*
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* Note that resuming the suspended pool on the remote host would invalidate
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* this guarantee, and so it is not allowed.
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*
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* The factor of 2 provides a conservative safety factor and derives from
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* MMP_IMPORT_SAFETY_FACTOR;
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*
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* 2) If uberblock was written by zfs-0.8 or newer and fail_intervals == 0:
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* (ub_mmp_config.multihost_interval + ub_mmp_delay) *
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* zfs_multihost_import_intervals
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*
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* In this case no guarantee can provided. However, as long as some devices
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* are healthy and connected, it is likely that at least one write will land
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* within (multihost_interval + mmp_delay) because multihost_interval is
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* enough time for a write to be attempted to each leaf vdev, and mmp_delay
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* is enough for one to land, based on past delays. Multiplying by
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* zfs_multihost_import_intervals provides a conservative safety factor.
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*
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* 3) If uberblock was written by zfs-0.7:
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* (zfs_multihost_interval + ub_mmp_delay) * zfs_multihost_import_intervals
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*
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* The same logic as case #2 applies, but we do not know remote tunables.
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*
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* We use the local value for zfs_multihost_interval because the original MMP
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* did not record this value in the uberblock.
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*
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* ub_mmp_delay >= (zfs_multihost_interval / leaves), so if the other host
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* has a much larger zfs_multihost_interval set, ub_mmp_delay will reflect
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* that. We will have waited enough time for zfs_multihost_import_intervals
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* writes to be issued and all but one to land.
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*
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* single device pool example delays
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*
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* import_delay = (1 + 1) * 20 = 40s #defaults, no I/O delay
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* import_delay = (1 + 10) * 20 = 220s #defaults, 10s I/O delay
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* import_delay = (10 + 10) * 20 = 400s #10s multihost_interval,
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* no I/O delay
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* 100 device pool example delays
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*
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* import_delay = (1 + .01) * 20 = 20s #defaults, no I/O delay
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* import_delay = (1 + 10) * 20 = 220s #defaults, 10s I/O delay
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* import_delay = (10 + .1) * 20 = 202s #10s multihost_interval,
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* no I/O delay
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*
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* 4) Otherwise, this uberblock was written by a pre-MMP zfs:
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* zfs_multihost_import_intervals * zfs_multihost_interval
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*
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* In this case local tunables are used. By default this product = 10s, long
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* enough for a pool with any activity at all to write at least one
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* uberblock. No guarantee can be provided.
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*
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* Additionally, the duration is then extended by a random 25% to attempt to to
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* detect simultaneous imports. For example, if both partner hosts are rebooted
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* at the same time and automatically attempt to import the pool.
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*/
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/*
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* Used to control the frequency of mmp writes which are performed when the
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* 'multihost' pool property is on. This is one factor used to determine the
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* length of the activity check during import.
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*
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* On average an mmp write will be issued for each leaf vdev every
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* zfs_multihost_interval milliseconds. In practice, the observed period can
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* vary with the I/O load and this observed value is the ub_mmp_delay which is
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* stored in the uberblock. The minimum allowed value is 100 ms.
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*/
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ulong_t zfs_multihost_interval = MMP_DEFAULT_INTERVAL;
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/*
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* Used to control the duration of the activity test on import. Smaller values
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* of zfs_multihost_import_intervals will reduce the import time but increase
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* the risk of failing to detect an active pool. The total activity check time
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* is never allowed to drop below one second. A value of 0 is ignored and
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* treated as if it was set to 1.
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*/
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uint_t zfs_multihost_import_intervals = MMP_DEFAULT_IMPORT_INTERVALS;
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/*
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* Controls the behavior of the pool when mmp write failures or delays are
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* detected.
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*
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* When zfs_multihost_fail_intervals = 0, mmp write failures or delays are
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* ignored. The failures will still be reported to the ZED which depending on
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* its configuration may take action such as suspending the pool or taking a
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* device offline.
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*
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* When zfs_multihost_fail_intervals > 0, the pool will be suspended if
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* zfs_multihost_fail_intervals * zfs_multihost_interval milliseconds pass
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* without a successful mmp write. This guarantees the activity test will see
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* mmp writes if the pool is imported. A value of 1 is ignored and treated as
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* if it was set to 2, because a single leaf vdev pool will issue a write once
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* per multihost_interval and thus any variation in latency would cause the
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* pool to be suspended.
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*/
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uint_t zfs_multihost_fail_intervals = MMP_DEFAULT_FAIL_INTERVALS;
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char *mmp_tag = "mmp_write_uberblock";
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static void mmp_thread(void *arg);
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void
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mmp_init(spa_t *spa)
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{
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mmp_thread_t *mmp = &spa->spa_mmp;
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mutex_init(&mmp->mmp_thread_lock, NULL, MUTEX_DEFAULT, NULL);
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cv_init(&mmp->mmp_thread_cv, NULL, CV_DEFAULT, NULL);
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mutex_init(&mmp->mmp_io_lock, NULL, MUTEX_DEFAULT, NULL);
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mmp->mmp_kstat_id = 1;
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}
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void
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mmp_fini(spa_t *spa)
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{
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mmp_thread_t *mmp = &spa->spa_mmp;
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mutex_destroy(&mmp->mmp_thread_lock);
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cv_destroy(&mmp->mmp_thread_cv);
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mutex_destroy(&mmp->mmp_io_lock);
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}
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static void
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mmp_thread_enter(mmp_thread_t *mmp, callb_cpr_t *cpr)
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{
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CALLB_CPR_INIT(cpr, &mmp->mmp_thread_lock, callb_generic_cpr, FTAG);
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mutex_enter(&mmp->mmp_thread_lock);
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}
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static void
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mmp_thread_exit(mmp_thread_t *mmp, kthread_t **mpp, callb_cpr_t *cpr)
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{
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ASSERT(*mpp != NULL);
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*mpp = NULL;
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cv_broadcast(&mmp->mmp_thread_cv);
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CALLB_CPR_EXIT(cpr); /* drops &mmp->mmp_thread_lock */
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thread_exit();
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}
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void
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mmp_thread_start(spa_t *spa)
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{
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mmp_thread_t *mmp = &spa->spa_mmp;
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if (spa_writeable(spa)) {
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mutex_enter(&mmp->mmp_thread_lock);
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if (!mmp->mmp_thread) {
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mmp->mmp_thread = thread_create(NULL, 0, mmp_thread,
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spa, 0, &p0, TS_RUN, defclsyspri);
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zfs_dbgmsg("MMP thread started pool '%s' "
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"gethrtime %llu", spa_name(spa), gethrtime());
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}
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mutex_exit(&mmp->mmp_thread_lock);
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}
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}
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void
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mmp_thread_stop(spa_t *spa)
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{
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mmp_thread_t *mmp = &spa->spa_mmp;
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mutex_enter(&mmp->mmp_thread_lock);
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mmp->mmp_thread_exiting = 1;
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cv_broadcast(&mmp->mmp_thread_cv);
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while (mmp->mmp_thread) {
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cv_wait(&mmp->mmp_thread_cv, &mmp->mmp_thread_lock);
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}
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mutex_exit(&mmp->mmp_thread_lock);
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zfs_dbgmsg("MMP thread stopped pool '%s' gethrtime %llu",
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spa_name(spa), gethrtime());
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ASSERT(mmp->mmp_thread == NULL);
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mmp->mmp_thread_exiting = 0;
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}
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typedef enum mmp_vdev_state_flag {
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MMP_FAIL_NOT_WRITABLE = (1 << 0),
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MMP_FAIL_WRITE_PENDING = (1 << 1),
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} mmp_vdev_state_flag_t;
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/*
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* Find a leaf vdev to write an MMP block to. It must not have an outstanding
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* mmp write (if so a new write will also likely block). If there is no usable
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* leaf, a nonzero error value is returned. The error value returned is a bit
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* field.
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*
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* MMP_FAIL_WRITE_PENDING One or more leaf vdevs are writeable, but have an
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* outstanding MMP write.
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* MMP_FAIL_NOT_WRITABLE One or more leaf vdevs are not writeable.
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*/
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static int
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mmp_next_leaf(spa_t *spa)
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{
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vdev_t *leaf;
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vdev_t *starting_leaf;
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int fail_mask = 0;
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ASSERT(MUTEX_HELD(&spa->spa_mmp.mmp_io_lock));
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ASSERT(spa_config_held(spa, SCL_STATE, RW_READER));
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ASSERT(list_link_active(&spa->spa_leaf_list.list_head) == B_TRUE);
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ASSERT(!list_is_empty(&spa->spa_leaf_list));
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if (spa->spa_mmp.mmp_leaf_last_gen != spa->spa_leaf_list_gen) {
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spa->spa_mmp.mmp_last_leaf = list_head(&spa->spa_leaf_list);
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spa->spa_mmp.mmp_leaf_last_gen = spa->spa_leaf_list_gen;
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}
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leaf = spa->spa_mmp.mmp_last_leaf;
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if (leaf == NULL)
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leaf = list_head(&spa->spa_leaf_list);
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starting_leaf = leaf;
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do {
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leaf = list_next(&spa->spa_leaf_list, leaf);
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if (leaf == NULL)
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leaf = list_head(&spa->spa_leaf_list);
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if (!vdev_writeable(leaf)) {
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fail_mask |= MMP_FAIL_NOT_WRITABLE;
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} else if (leaf->vdev_mmp_pending != 0) {
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fail_mask |= MMP_FAIL_WRITE_PENDING;
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} else {
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spa->spa_mmp.mmp_last_leaf = leaf;
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return (0);
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}
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} while (leaf != starting_leaf);
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ASSERT(fail_mask);
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return (fail_mask);
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}
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/*
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* MMP writes are issued on a fixed schedule, but may complete at variable,
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* much longer, intervals. The mmp_delay captures long periods between
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* successful writes for any reason, including disk latency, scheduling delays,
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* etc.
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*
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* The mmp_delay is usually calculated as a decaying average, but if the latest
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* delay is higher we do not average it, so that we do not hide sudden spikes
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* which the importing host must wait for.
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*
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* If writes are occurring frequently, such as due to a high rate of txg syncs,
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* the mmp_delay could become very small. Since those short delays depend on
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* activity we cannot count on, we never allow mmp_delay to get lower than rate
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* expected if only mmp_thread writes occur.
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*
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* If an mmp write was skipped or fails, and we have already waited longer than
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* mmp_delay, we need to update it so the next write reflects the longer delay.
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*
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* Do not set mmp_delay if the multihost property is not on, so as not to
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* trigger an activity check on import.
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*/
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static void
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mmp_delay_update(spa_t *spa, boolean_t write_completed)
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{
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mmp_thread_t *mts = &spa->spa_mmp;
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hrtime_t delay = gethrtime() - mts->mmp_last_write;
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ASSERT(MUTEX_HELD(&mts->mmp_io_lock));
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if (spa_multihost(spa) == B_FALSE) {
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mts->mmp_delay = 0;
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return;
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}
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if (delay > mts->mmp_delay)
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mts->mmp_delay = delay;
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if (write_completed == B_FALSE)
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return;
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mts->mmp_last_write = gethrtime();
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/*
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* strictly less than, in case delay was changed above.
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*/
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if (delay < mts->mmp_delay) {
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hrtime_t min_delay =
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MSEC2NSEC(MMP_INTERVAL_OK(zfs_multihost_interval)) /
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MAX(1, vdev_count_leaves(spa));
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mts->mmp_delay = MAX(((delay + mts->mmp_delay * 127) / 128),
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min_delay);
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}
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}
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static void
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mmp_write_done(zio_t *zio)
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{
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spa_t *spa = zio->io_spa;
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vdev_t *vd = zio->io_vd;
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mmp_thread_t *mts = zio->io_private;
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mutex_enter(&mts->mmp_io_lock);
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uint64_t mmp_kstat_id = vd->vdev_mmp_kstat_id;
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hrtime_t mmp_write_duration = gethrtime() - vd->vdev_mmp_pending;
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mmp_delay_update(spa, (zio->io_error == 0));
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vd->vdev_mmp_pending = 0;
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vd->vdev_mmp_kstat_id = 0;
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mutex_exit(&mts->mmp_io_lock);
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spa_config_exit(spa, SCL_STATE, mmp_tag);
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spa_mmp_history_set(spa, mmp_kstat_id, zio->io_error,
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mmp_write_duration);
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abd_free(zio->io_abd);
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}
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/*
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* When the uberblock on-disk is updated by a spa_sync,
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* creating a new "best" uberblock, update the one stored
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* in the mmp thread state, used for mmp writes.
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*/
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void
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mmp_update_uberblock(spa_t *spa, uberblock_t *ub)
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{
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mmp_thread_t *mmp = &spa->spa_mmp;
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mutex_enter(&mmp->mmp_io_lock);
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mmp->mmp_ub = *ub;
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mmp->mmp_seq = 1;
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mmp->mmp_ub.ub_timestamp = gethrestime_sec();
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mmp_delay_update(spa, B_TRUE);
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mutex_exit(&mmp->mmp_io_lock);
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}
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/*
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* Choose a random vdev, label, and MMP block, and write over it
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* with a copy of the last-synced uberblock, whose timestamp
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* has been updated to reflect that the pool is in use.
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*/
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static void
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mmp_write_uberblock(spa_t *spa)
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{
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int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL;
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mmp_thread_t *mmp = &spa->spa_mmp;
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uberblock_t *ub;
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vdev_t *vd = NULL;
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int label, error;
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uint64_t offset;
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hrtime_t lock_acquire_time = gethrtime();
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spa_config_enter(spa, SCL_STATE, mmp_tag, RW_READER);
|
|
lock_acquire_time = gethrtime() - lock_acquire_time;
|
|
if (lock_acquire_time > (MSEC2NSEC(MMP_MIN_INTERVAL) / 10))
|
|
zfs_dbgmsg("MMP SCL_STATE acquisition pool '%s' took %llu ns "
|
|
"gethrtime %llu", spa_name(spa), lock_acquire_time,
|
|
gethrtime());
|
|
|
|
mutex_enter(&mmp->mmp_io_lock);
|
|
|
|
error = mmp_next_leaf(spa);
|
|
|
|
/*
|
|
* spa_mmp_history has two types of entries:
|
|
* Issued MMP write: records time issued, error status, etc.
|
|
* Skipped MMP write: an MMP write could not be issued because no
|
|
* suitable leaf vdev was available. See comment above struct
|
|
* spa_mmp_history for details.
|
|
*/
|
|
|
|
if (error) {
|
|
mmp_delay_update(spa, B_FALSE);
|
|
if (mmp->mmp_skip_error == error) {
|
|
spa_mmp_history_set_skip(spa, mmp->mmp_kstat_id - 1);
|
|
} else {
|
|
mmp->mmp_skip_error = error;
|
|
spa_mmp_history_add(spa, mmp->mmp_ub.ub_txg,
|
|
gethrestime_sec(), mmp->mmp_delay, NULL, 0,
|
|
mmp->mmp_kstat_id++, error);
|
|
zfs_dbgmsg("MMP error choosing leaf pool '%s' "
|
|
"gethrtime %llu fail_mask %#x", spa_name(spa),
|
|
gethrtime(), error);
|
|
}
|
|
mutex_exit(&mmp->mmp_io_lock);
|
|
spa_config_exit(spa, SCL_STATE, mmp_tag);
|
|
return;
|
|
}
|
|
|
|
vd = spa->spa_mmp.mmp_last_leaf;
|
|
if (mmp->mmp_skip_error != 0) {
|
|
mmp->mmp_skip_error = 0;
|
|
zfs_dbgmsg("MMP write after skipping due to unavailable "
|
|
"leaves, pool '%s' gethrtime %llu leaf %#llu",
|
|
spa_name(spa), gethrtime(), vd->vdev_guid);
|
|
}
|
|
|
|
if (mmp->mmp_zio_root == NULL)
|
|
mmp->mmp_zio_root = zio_root(spa, NULL, NULL,
|
|
flags | ZIO_FLAG_GODFATHER);
|
|
|
|
if (mmp->mmp_ub.ub_timestamp != gethrestime_sec()) {
|
|
/*
|
|
* Want to reset mmp_seq when timestamp advances because after
|
|
* an mmp_seq wrap new values will not be chosen by
|
|
* uberblock_compare() as the "best".
|
|
*/
|
|
mmp->mmp_ub.ub_timestamp = gethrestime_sec();
|
|
mmp->mmp_seq = 1;
|
|
}
|
|
|
|
ub = &mmp->mmp_ub;
|
|
ub->ub_mmp_magic = MMP_MAGIC;
|
|
ub->ub_mmp_delay = mmp->mmp_delay;
|
|
ub->ub_mmp_config = MMP_SEQ_SET(mmp->mmp_seq) |
|
|
MMP_INTERVAL_SET(MMP_INTERVAL_OK(zfs_multihost_interval)) |
|
|
MMP_FAIL_INT_SET(MMP_FAIL_INTVS_OK(
|
|
zfs_multihost_fail_intervals));
|
|
vd->vdev_mmp_pending = gethrtime();
|
|
vd->vdev_mmp_kstat_id = mmp->mmp_kstat_id;
|
|
|
|
zio_t *zio = zio_null(mmp->mmp_zio_root, spa, NULL, NULL, NULL, flags);
|
|
abd_t *ub_abd = abd_alloc_for_io(VDEV_UBERBLOCK_SIZE(vd), B_TRUE);
|
|
abd_zero(ub_abd, VDEV_UBERBLOCK_SIZE(vd));
|
|
abd_copy_from_buf(ub_abd, ub, sizeof (uberblock_t));
|
|
|
|
mmp->mmp_seq++;
|
|
mmp->mmp_kstat_id++;
|
|
mutex_exit(&mmp->mmp_io_lock);
|
|
|
|
offset = VDEV_UBERBLOCK_OFFSET(vd, VDEV_UBERBLOCK_COUNT(vd) -
|
|
MMP_BLOCKS_PER_LABEL + spa_get_random(MMP_BLOCKS_PER_LABEL));
|
|
|
|
label = spa_get_random(VDEV_LABELS);
|
|
vdev_label_write(zio, vd, label, ub_abd, offset,
|
|
VDEV_UBERBLOCK_SIZE(vd), mmp_write_done, mmp,
|
|
flags | ZIO_FLAG_DONT_PROPAGATE);
|
|
|
|
(void) spa_mmp_history_add(spa, ub->ub_txg, ub->ub_timestamp,
|
|
ub->ub_mmp_delay, vd, label, vd->vdev_mmp_kstat_id, 0);
|
|
|
|
zio_nowait(zio);
|
|
}
|
|
|
|
static void
|
|
mmp_thread(void *arg)
|
|
{
|
|
spa_t *spa = (spa_t *)arg;
|
|
mmp_thread_t *mmp = &spa->spa_mmp;
|
|
boolean_t suspended = spa_suspended(spa);
|
|
boolean_t multihost = spa_multihost(spa);
|
|
uint64_t mmp_interval = MSEC2NSEC(MMP_INTERVAL_OK(
|
|
zfs_multihost_interval));
|
|
uint32_t mmp_fail_intervals = MMP_FAIL_INTVS_OK(
|
|
zfs_multihost_fail_intervals);
|
|
hrtime_t mmp_fail_ns = mmp_fail_intervals * mmp_interval;
|
|
boolean_t last_spa_suspended = suspended;
|
|
boolean_t last_spa_multihost = multihost;
|
|
uint64_t last_mmp_interval = mmp_interval;
|
|
uint32_t last_mmp_fail_intervals = mmp_fail_intervals;
|
|
hrtime_t last_mmp_fail_ns = mmp_fail_ns;
|
|
callb_cpr_t cpr;
|
|
int skip_wait = 0;
|
|
|
|
mmp_thread_enter(mmp, &cpr);
|
|
|
|
/*
|
|
* There have been no MMP writes yet. Setting mmp_last_write here gives
|
|
* us one mmp_fail_ns period, which is consistent with the activity
|
|
* check duration, to try to land an MMP write before MMP suspends the
|
|
* pool (if so configured).
|
|
*/
|
|
|
|
mutex_enter(&mmp->mmp_io_lock);
|
|
mmp->mmp_last_write = gethrtime();
|
|
mmp->mmp_delay = MSEC2NSEC(MMP_INTERVAL_OK(zfs_multihost_interval));
|
|
mutex_exit(&mmp->mmp_io_lock);
|
|
|
|
while (!mmp->mmp_thread_exiting) {
|
|
hrtime_t next_time = gethrtime() +
|
|
MSEC2NSEC(MMP_DEFAULT_INTERVAL);
|
|
int leaves = MAX(vdev_count_leaves(spa), 1);
|
|
|
|
/* Detect changes in tunables or state */
|
|
|
|
last_spa_suspended = suspended;
|
|
last_spa_multihost = multihost;
|
|
suspended = spa_suspended(spa);
|
|
multihost = spa_multihost(spa);
|
|
|
|
last_mmp_interval = mmp_interval;
|
|
last_mmp_fail_intervals = mmp_fail_intervals;
|
|
last_mmp_fail_ns = mmp_fail_ns;
|
|
mmp_interval = MSEC2NSEC(MMP_INTERVAL_OK(
|
|
zfs_multihost_interval));
|
|
mmp_fail_intervals = MMP_FAIL_INTVS_OK(
|
|
zfs_multihost_fail_intervals);
|
|
|
|
/* Smooth so pool is not suspended when reducing tunables */
|
|
if (mmp_fail_intervals * mmp_interval < mmp_fail_ns) {
|
|
mmp_fail_ns = (mmp_fail_ns * 31 +
|
|
mmp_fail_intervals * mmp_interval) / 32;
|
|
} else {
|
|
mmp_fail_ns = mmp_fail_intervals *
|
|
mmp_interval;
|
|
}
|
|
|
|
if (mmp_interval != last_mmp_interval ||
|
|
mmp_fail_intervals != last_mmp_fail_intervals) {
|
|
/*
|
|
* We want other hosts to see new tunables as quickly as
|
|
* possible. Write out at higher frequency than usual.
|
|
*/
|
|
skip_wait += leaves;
|
|
}
|
|
|
|
if (multihost)
|
|
next_time = gethrtime() + mmp_interval / leaves;
|
|
|
|
if (mmp_fail_ns != last_mmp_fail_ns) {
|
|
zfs_dbgmsg("MMP interval change pool '%s' "
|
|
"gethrtime %llu last_mmp_interval %llu "
|
|
"mmp_interval %llu last_mmp_fail_intervals %u "
|
|
"mmp_fail_intervals %u mmp_fail_ns %llu "
|
|
"skip_wait %d leaves %d next_time %llu",
|
|
spa_name(spa), gethrtime(), last_mmp_interval,
|
|
mmp_interval, last_mmp_fail_intervals,
|
|
mmp_fail_intervals, mmp_fail_ns, skip_wait, leaves,
|
|
next_time);
|
|
}
|
|
|
|
/*
|
|
* MMP off => on, or suspended => !suspended:
|
|
* No writes occurred recently. Update mmp_last_write to give
|
|
* us some time to try.
|
|
*/
|
|
if ((!last_spa_multihost && multihost) ||
|
|
(last_spa_suspended && !suspended)) {
|
|
zfs_dbgmsg("MMP state change pool '%s': gethrtime %llu "
|
|
"last_spa_multihost %u multihost %u "
|
|
"last_spa_suspended %u suspended %u",
|
|
spa_name(spa), last_spa_multihost, multihost,
|
|
last_spa_suspended, suspended);
|
|
mutex_enter(&mmp->mmp_io_lock);
|
|
mmp->mmp_last_write = gethrtime();
|
|
mmp->mmp_delay = mmp_interval;
|
|
mutex_exit(&mmp->mmp_io_lock);
|
|
}
|
|
|
|
/*
|
|
* MMP on => off:
|
|
* mmp_delay == 0 tells importing node to skip activity check.
|
|
*/
|
|
if (last_spa_multihost && !multihost) {
|
|
mutex_enter(&mmp->mmp_io_lock);
|
|
mmp->mmp_delay = 0;
|
|
mutex_exit(&mmp->mmp_io_lock);
|
|
}
|
|
|
|
/*
|
|
* Suspend the pool if no MMP write has succeeded in over
|
|
* mmp_interval * mmp_fail_intervals nanoseconds.
|
|
*/
|
|
if (multihost && !suspended && mmp_fail_intervals &&
|
|
(gethrtime() - mmp->mmp_last_write) > mmp_fail_ns) {
|
|
zfs_dbgmsg("MMP suspending pool '%s': gethrtime %llu "
|
|
"mmp_last_write %llu mmp_interval %llu "
|
|
"mmp_fail_intervals %llu mmp_fail_ns %llu",
|
|
spa_name(spa), (u_longlong_t)gethrtime(),
|
|
(u_longlong_t)mmp->mmp_last_write,
|
|
(u_longlong_t)mmp_interval,
|
|
(u_longlong_t)mmp_fail_intervals,
|
|
(u_longlong_t)mmp_fail_ns);
|
|
cmn_err(CE_WARN, "MMP writes to pool '%s' have not "
|
|
"succeeded in over %llu ms; suspending pool. "
|
|
"Hrtime %llu",
|
|
spa_name(spa),
|
|
NSEC2MSEC(gethrtime() - mmp->mmp_last_write),
|
|
gethrtime());
|
|
zio_suspend(spa, NULL, ZIO_SUSPEND_MMP);
|
|
}
|
|
|
|
if (multihost && !suspended)
|
|
mmp_write_uberblock(spa);
|
|
|
|
if (skip_wait > 0) {
|
|
next_time = gethrtime() + MSEC2NSEC(MMP_MIN_INTERVAL) /
|
|
leaves;
|
|
skip_wait--;
|
|
}
|
|
|
|
CALLB_CPR_SAFE_BEGIN(&cpr);
|
|
(void) cv_timedwait_idle_hires(&mmp->mmp_thread_cv,
|
|
&mmp->mmp_thread_lock, next_time, USEC2NSEC(100),
|
|
CALLOUT_FLAG_ABSOLUTE);
|
|
CALLB_CPR_SAFE_END(&cpr, &mmp->mmp_thread_lock);
|
|
}
|
|
|
|
/* Outstanding writes are allowed to complete. */
|
|
zio_wait(mmp->mmp_zio_root);
|
|
|
|
mmp->mmp_zio_root = NULL;
|
|
mmp_thread_exit(mmp, &mmp->mmp_thread, &cpr);
|
|
}
|
|
|
|
/*
|
|
* Signal the MMP thread to wake it, when it is sleeping on
|
|
* its cv. Used when some module parameter has changed and
|
|
* we want the thread to know about it.
|
|
* Only signal if the pool is active and mmp thread is
|
|
* running, otherwise there is no thread to wake.
|
|
*/
|
|
static void
|
|
mmp_signal_thread(spa_t *spa)
|
|
{
|
|
mmp_thread_t *mmp = &spa->spa_mmp;
|
|
|
|
mutex_enter(&mmp->mmp_thread_lock);
|
|
if (mmp->mmp_thread)
|
|
cv_broadcast(&mmp->mmp_thread_cv);
|
|
mutex_exit(&mmp->mmp_thread_lock);
|
|
}
|
|
|
|
void
|
|
mmp_signal_all_threads(void)
|
|
{
|
|
spa_t *spa = NULL;
|
|
|
|
mutex_enter(&spa_namespace_lock);
|
|
while ((spa = spa_next(spa))) {
|
|
if (spa->spa_state == POOL_STATE_ACTIVE)
|
|
mmp_signal_thread(spa);
|
|
}
|
|
mutex_exit(&spa_namespace_lock);
|
|
}
|
|
|
|
/* BEGIN CSTYLED */
|
|
ZFS_MODULE_PARAM_CALL(zfs_multihost, zfs_multihost_, interval,
|
|
param_set_multihost_interval, param_get_ulong, ZMOD_RW,
|
|
"Milliseconds between mmp writes to each leaf");
|
|
/* END CSTYLED */
|
|
|
|
ZFS_MODULE_PARAM(zfs_multihost, zfs_multihost_, fail_intervals, UINT, ZMOD_RW,
|
|
"Max allowed period without a successful mmp write");
|
|
|
|
ZFS_MODULE_PARAM(zfs_multihost, zfs_multihost_, import_intervals, UINT, ZMOD_RW,
|
|
"Number of zfs_multihost_interval periods to wait for activity");
|