a1d477c24c
OpenZFS 7614 - zfs device evacuation/removal OpenZFS 9064 - remove_mirror should wait for device removal to complete This project allows top-level vdevs to be removed from the storage pool with "zpool remove", reducing the total amount of storage in the pool. This operation copies all allocated regions of the device to be removed onto other devices, recording the mapping from old to new location. After the removal is complete, read and free operations to the removed (now "indirect") vdev must be remapped and performed at the new location on disk. The indirect mapping table is kept in memory whenever the pool is loaded, so there is minimal performance overhead when doing operations on the indirect vdev. The size of the in-memory mapping table will be reduced when its entries become "obsolete" because they are no longer used by any block pointers in the pool. An entry becomes obsolete when all the blocks that use it are freed. An entry can also become obsolete when all the snapshots that reference it are deleted, and the block pointers that reference it have been "remapped" in all filesystems/zvols (and clones). Whenever an indirect block is written, all the block pointers in it will be "remapped" to their new (concrete) locations if possible. This process can be accelerated by using the "zfs remap" command to proactively rewrite all indirect blocks that reference indirect (removed) vdevs. Note that when a device is removed, we do not verify the checksum of the data that is copied. This makes the process much faster, but if it were used on redundant vdevs (i.e. mirror or raidz vdevs), it would be possible to copy the wrong data, when we have the correct data on e.g. the other side of the mirror. At the moment, only mirrors and simple top-level vdevs can be removed and no removal is allowed if any of the top-level vdevs are raidz. Porting Notes: * Avoid zero-sized kmem_alloc() in vdev_compact_children(). The device evacuation code adds a dependency that vdev_compact_children() be able to properly empty the vdev_child array by setting it to NULL and zeroing vdev_children. Under Linux, kmem_alloc() and related functions return a sentinel pointer rather than NULL for zero-sized allocations. * Remove comment regarding "mpt" driver where zfs_remove_max_segment is initialized to SPA_MAXBLOCKSIZE. Change zfs_condense_indirect_commit_entry_delay_ticks to zfs_condense_indirect_commit_entry_delay_ms for consistency with most other tunables in which delays are specified in ms. * ZTS changes: Use set_tunable rather than mdb Use zpool sync as appropriate Use sync_pool instead of sync Kill jobs during test_removal_with_operation to allow unmount/export Don't add non-disk names such as "mirror" or "raidz" to $DISKS Use $TEST_BASE_DIR instead of /tmp Increase HZ from 100 to 1000 which is more common on Linux removal_multiple_indirection.ksh Reduce iterations in order to not time out on the code coverage builders. removal_resume_export: Functionally, the test case is correct but there exists a race where the kernel thread hasn't been fully started yet and is not visible. Wait for up to 1 second for the removal thread to be started before giving up on it. Also, increase the amount of data copied in order that the removal not finish before the export has a chance to fail. * MMP compatibility, the concept of concrete versus non-concrete devices has slightly changed the semantics of vdev_writeable(). Update mmp_random_leaf_impl() accordingly. * Updated dbuf_remap() to handle the org.zfsonlinux:large_dnode pool feature which is not supported by OpenZFS. * Added support for new vdev removal tracepoints. * Test cases removal_with_zdb and removal_condense_export have been intentionally disabled. When run manually they pass as intended, but when running in the automated test environment they produce unreliable results on the latest Fedora release. They may work better once the upstream pool import refectoring is merged into ZoL at which point they will be re-enabled. Authored by: Matthew Ahrens <mahrens@delphix.com> Reviewed-by: Alex Reece <alex@delphix.com> Reviewed-by: George Wilson <george.wilson@delphix.com> Reviewed-by: John Kennedy <john.kennedy@delphix.com> Reviewed-by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Richard Laager <rlaager@wiktel.com> Reviewed by: Tim Chase <tim@chase2k.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Garrett D'Amore <garrett@damore.org> Ported-by: Tim Chase <tim@chase2k.com> Signed-off-by: Tim Chase <tim@chase2k.com> OpenZFS-issue: https://www.illumos.org/issues/7614 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f539f1eb Closes #6900
379 lines
11 KiB
C
379 lines
11 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 2009 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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/*
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* Copyright (c) 2013, 2015 by Delphix. All rights reserved.
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*/
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#include <sys/zfs_context.h>
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#include <sys/dnode.h>
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#include <sys/dmu_objset.h>
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#include <sys/dmu_zfetch.h>
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#include <sys/dmu.h>
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#include <sys/dbuf.h>
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#include <sys/kstat.h>
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/*
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* This tunable disables predictive prefetch. Note that it leaves "prescient"
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* prefetch (e.g. prefetch for zfs send) intact. Unlike predictive prefetch,
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* prescient prefetch never issues i/os that end up not being needed,
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* so it can't hurt performance.
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*/
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int zfs_prefetch_disable = B_FALSE;
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/* max # of streams per zfetch */
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unsigned int zfetch_max_streams = 8;
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/* min time before stream reclaim */
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unsigned int zfetch_min_sec_reap = 2;
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/* max bytes to prefetch per stream (default 8MB) */
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unsigned int zfetch_max_distance = 8 * 1024 * 1024;
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/* max bytes to prefetch indirects for per stream (default 64MB) */
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unsigned int zfetch_max_idistance = 64 * 1024 * 1024;
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/* max number of bytes in an array_read in which we allow prefetching (1MB) */
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unsigned long zfetch_array_rd_sz = 1024 * 1024;
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typedef struct zfetch_stats {
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kstat_named_t zfetchstat_hits;
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kstat_named_t zfetchstat_misses;
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kstat_named_t zfetchstat_max_streams;
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} zfetch_stats_t;
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static zfetch_stats_t zfetch_stats = {
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{ "hits", KSTAT_DATA_UINT64 },
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{ "misses", KSTAT_DATA_UINT64 },
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{ "max_streams", KSTAT_DATA_UINT64 },
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};
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#define ZFETCHSTAT_BUMP(stat) \
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atomic_inc_64(&zfetch_stats.stat.value.ui64);
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kstat_t *zfetch_ksp;
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void
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zfetch_init(void)
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{
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zfetch_ksp = kstat_create("zfs", 0, "zfetchstats", "misc",
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KSTAT_TYPE_NAMED, sizeof (zfetch_stats) / sizeof (kstat_named_t),
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KSTAT_FLAG_VIRTUAL);
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if (zfetch_ksp != NULL) {
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zfetch_ksp->ks_data = &zfetch_stats;
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kstat_install(zfetch_ksp);
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}
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}
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void
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zfetch_fini(void)
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{
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if (zfetch_ksp != NULL) {
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kstat_delete(zfetch_ksp);
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zfetch_ksp = NULL;
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}
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}
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/*
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* This takes a pointer to a zfetch structure and a dnode. It performs the
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* necessary setup for the zfetch structure, grokking data from the
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* associated dnode.
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*/
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void
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dmu_zfetch_init(zfetch_t *zf, dnode_t *dno)
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{
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if (zf == NULL)
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return;
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zf->zf_dnode = dno;
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list_create(&zf->zf_stream, sizeof (zstream_t),
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offsetof(zstream_t, zs_node));
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rw_init(&zf->zf_rwlock, NULL, RW_DEFAULT, NULL);
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}
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static void
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dmu_zfetch_stream_remove(zfetch_t *zf, zstream_t *zs)
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{
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ASSERT(RW_WRITE_HELD(&zf->zf_rwlock));
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list_remove(&zf->zf_stream, zs);
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mutex_destroy(&zs->zs_lock);
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kmem_free(zs, sizeof (*zs));
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}
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/*
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* Clean-up state associated with a zfetch structure (e.g. destroy the
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* streams). This doesn't free the zfetch_t itself, that's left to the caller.
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*/
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void
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dmu_zfetch_fini(zfetch_t *zf)
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{
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zstream_t *zs;
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ASSERT(!RW_LOCK_HELD(&zf->zf_rwlock));
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rw_enter(&zf->zf_rwlock, RW_WRITER);
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while ((zs = list_head(&zf->zf_stream)) != NULL)
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dmu_zfetch_stream_remove(zf, zs);
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rw_exit(&zf->zf_rwlock);
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list_destroy(&zf->zf_stream);
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rw_destroy(&zf->zf_rwlock);
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zf->zf_dnode = NULL;
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}
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/*
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* If there aren't too many streams already, create a new stream.
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* The "blkid" argument is the next block that we expect this stream to access.
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* While we're here, clean up old streams (which haven't been
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* accessed for at least zfetch_min_sec_reap seconds).
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*/
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static void
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dmu_zfetch_stream_create(zfetch_t *zf, uint64_t blkid)
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{
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zstream_t *zs_next;
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int numstreams = 0;
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ASSERT(RW_WRITE_HELD(&zf->zf_rwlock));
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/*
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* Clean up old streams.
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*/
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for (zstream_t *zs = list_head(&zf->zf_stream);
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zs != NULL; zs = zs_next) {
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zs_next = list_next(&zf->zf_stream, zs);
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if (((gethrtime() - zs->zs_atime) / NANOSEC) >
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zfetch_min_sec_reap)
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dmu_zfetch_stream_remove(zf, zs);
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else
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numstreams++;
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}
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/*
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* The maximum number of streams is normally zfetch_max_streams,
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* but for small files we lower it such that it's at least possible
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* for all the streams to be non-overlapping.
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*
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* If we are already at the maximum number of streams for this file,
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* even after removing old streams, then don't create this stream.
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*/
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uint32_t max_streams = MAX(1, MIN(zfetch_max_streams,
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zf->zf_dnode->dn_maxblkid * zf->zf_dnode->dn_datablksz /
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zfetch_max_distance));
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if (numstreams >= max_streams) {
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ZFETCHSTAT_BUMP(zfetchstat_max_streams);
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return;
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}
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zstream_t *zs = kmem_zalloc(sizeof (*zs), KM_SLEEP);
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zs->zs_blkid = blkid;
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zs->zs_pf_blkid = blkid;
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zs->zs_ipf_blkid = blkid;
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zs->zs_atime = gethrtime();
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mutex_init(&zs->zs_lock, NULL, MUTEX_DEFAULT, NULL);
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list_insert_head(&zf->zf_stream, zs);
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}
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/*
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* This is the predictive prefetch entry point. It associates dnode access
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* specified with blkid and nblks arguments with prefetch stream, predicts
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* further accesses based on that stats and initiates speculative prefetch.
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* fetch_data argument specifies whether actual data blocks should be fetched:
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* FALSE -- prefetch only indirect blocks for predicted data blocks;
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* TRUE -- prefetch predicted data blocks plus following indirect blocks.
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*/
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void
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dmu_zfetch(zfetch_t *zf, uint64_t blkid, uint64_t nblks, boolean_t fetch_data)
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{
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zstream_t *zs;
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int64_t pf_start, ipf_start, ipf_istart, ipf_iend;
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int64_t pf_ahead_blks, max_blks;
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int epbs, max_dist_blks, pf_nblks, ipf_nblks;
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uint64_t end_of_access_blkid;
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end_of_access_blkid = blkid + nblks;
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spa_t *spa = zf->zf_dnode->dn_objset->os_spa;
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if (zfs_prefetch_disable)
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return;
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/*
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* If we haven't yet loaded the indirect vdevs' mappings, we
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* can only read from blocks that we carefully ensure are on
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* concrete vdevs (or previously-loaded indirect vdevs). So we
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* can't allow the predictive prefetcher to attempt reads of other
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* blocks (e.g. of the MOS's dnode obejct).
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*/
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if (!spa_indirect_vdevs_loaded(spa))
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return;
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/*
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* As a fast path for small (single-block) files, ignore access
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* to the first block.
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*/
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if (blkid == 0)
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return;
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rw_enter(&zf->zf_rwlock, RW_READER);
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/*
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* Find matching prefetch stream. Depending on whether the accesses
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* are block-aligned, first block of the new access may either follow
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* the last block of the previous access, or be equal to it.
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*/
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for (zs = list_head(&zf->zf_stream); zs != NULL;
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zs = list_next(&zf->zf_stream, zs)) {
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if (blkid == zs->zs_blkid || blkid + 1 == zs->zs_blkid) {
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mutex_enter(&zs->zs_lock);
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/*
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* zs_blkid could have changed before we
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* acquired zs_lock; re-check them here.
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*/
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if (blkid == zs->zs_blkid) {
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break;
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} else if (blkid + 1 == zs->zs_blkid) {
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blkid++;
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nblks--;
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if (nblks == 0) {
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/* Already prefetched this before. */
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mutex_exit(&zs->zs_lock);
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rw_exit(&zf->zf_rwlock);
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return;
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}
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break;
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}
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mutex_exit(&zs->zs_lock);
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}
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}
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if (zs == NULL) {
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/*
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* This access is not part of any existing stream. Create
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* a new stream for it.
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*/
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ZFETCHSTAT_BUMP(zfetchstat_misses);
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if (rw_tryupgrade(&zf->zf_rwlock))
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dmu_zfetch_stream_create(zf, end_of_access_blkid);
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rw_exit(&zf->zf_rwlock);
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return;
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}
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/*
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* This access was to a block that we issued a prefetch for on
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* behalf of this stream. Issue further prefetches for this stream.
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*
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* Normally, we start prefetching where we stopped
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* prefetching last (zs_pf_blkid). But when we get our first
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* hit on this stream, zs_pf_blkid == zs_blkid, we don't
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* want to prefetch the block we just accessed. In this case,
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* start just after the block we just accessed.
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*/
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pf_start = MAX(zs->zs_pf_blkid, end_of_access_blkid);
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/*
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* Double our amount of prefetched data, but don't let the
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* prefetch get further ahead than zfetch_max_distance.
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*/
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if (fetch_data) {
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max_dist_blks =
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zfetch_max_distance >> zf->zf_dnode->dn_datablkshift;
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/*
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* Previously, we were (zs_pf_blkid - blkid) ahead. We
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* want to now be double that, so read that amount again,
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* plus the amount we are catching up by (i.e. the amount
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* read just now).
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*/
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pf_ahead_blks = zs->zs_pf_blkid - blkid + nblks;
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max_blks = max_dist_blks - (pf_start - end_of_access_blkid);
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pf_nblks = MIN(pf_ahead_blks, max_blks);
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} else {
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pf_nblks = 0;
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}
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zs->zs_pf_blkid = pf_start + pf_nblks;
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/*
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* Do the same for indirects, starting from where we stopped last,
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* or where we will stop reading data blocks (and the indirects
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* that point to them).
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*/
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ipf_start = MAX(zs->zs_ipf_blkid, zs->zs_pf_blkid);
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max_dist_blks = zfetch_max_idistance >> zf->zf_dnode->dn_datablkshift;
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/*
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* We want to double our distance ahead of the data prefetch
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* (or reader, if we are not prefetching data). Previously, we
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* were (zs_ipf_blkid - blkid) ahead. To double that, we read
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* that amount again, plus the amount we are catching up by
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* (i.e. the amount read now + the amount of data prefetched now).
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*/
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pf_ahead_blks = zs->zs_ipf_blkid - blkid + nblks + pf_nblks;
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max_blks = max_dist_blks - (ipf_start - end_of_access_blkid);
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ipf_nblks = MIN(pf_ahead_blks, max_blks);
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zs->zs_ipf_blkid = ipf_start + ipf_nblks;
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epbs = zf->zf_dnode->dn_indblkshift - SPA_BLKPTRSHIFT;
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ipf_istart = P2ROUNDUP(ipf_start, 1 << epbs) >> epbs;
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ipf_iend = P2ROUNDUP(zs->zs_ipf_blkid, 1 << epbs) >> epbs;
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zs->zs_atime = gethrtime();
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zs->zs_blkid = end_of_access_blkid;
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mutex_exit(&zs->zs_lock);
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rw_exit(&zf->zf_rwlock);
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/*
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* dbuf_prefetch() is asynchronous (even when it needs to read
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* indirect blocks), but we still prefer to drop our locks before
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* calling it to reduce the time we hold them.
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*/
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for (int i = 0; i < pf_nblks; i++) {
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dbuf_prefetch(zf->zf_dnode, 0, pf_start + i,
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ZIO_PRIORITY_ASYNC_READ, ARC_FLAG_PREDICTIVE_PREFETCH);
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}
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for (int64_t iblk = ipf_istart; iblk < ipf_iend; iblk++) {
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dbuf_prefetch(zf->zf_dnode, 1, iblk,
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ZIO_PRIORITY_ASYNC_READ, ARC_FLAG_PREDICTIVE_PREFETCH);
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}
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ZFETCHSTAT_BUMP(zfetchstat_hits);
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}
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#if defined(_KERNEL) && defined(HAVE_SPL)
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/* BEGIN CSTYLED */
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module_param(zfs_prefetch_disable, int, 0644);
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MODULE_PARM_DESC(zfs_prefetch_disable, "Disable all ZFS prefetching");
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module_param(zfetch_max_streams, uint, 0644);
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MODULE_PARM_DESC(zfetch_max_streams, "Max number of streams per zfetch");
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module_param(zfetch_min_sec_reap, uint, 0644);
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MODULE_PARM_DESC(zfetch_min_sec_reap, "Min time before stream reclaim");
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module_param(zfetch_max_distance, uint, 0644);
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MODULE_PARM_DESC(zfetch_max_distance,
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"Max bytes to prefetch per stream (default 8MB)");
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module_param(zfetch_array_rd_sz, ulong, 0644);
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MODULE_PARM_DESC(zfetch_array_rd_sz, "Number of bytes in a array_read");
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/* END CSTYLED */
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#endif
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