*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2018 by Delphix. All rights reserved.
+ * Copyright (c) 2014 Integros [integros.com]
+ * Copyright (c) 2018 Datto Inc.
*/
/* Portions Copyright 2010 Robert Milkowski */
#include <sys/zfs_context.h>
#include <sys/spa.h>
+#include <sys/spa_impl.h>
#include <sys/dmu.h>
#include <sys/zap.h>
#include <sys/arc.h>
#include <sys/stat.h>
-#include <sys/resource.h>
#include <sys/zil.h>
#include <sys/zil_impl.h>
#include <sys/dsl_dataset.h>
#include <sys/dmu_tx.h>
#include <sys/dsl_pool.h>
#include <sys/metaslab.h>
+#include <sys/trace_zil.h>
+#include <sys/abd.h>
/*
- * The zfs intent log (ZIL) saves transaction records of system calls
- * that change the file system in memory with enough information
- * to be able to replay them. These are stored in memory until
- * either the DMU transaction group (txg) commits them to the stable pool
- * and they can be discarded, or they are flushed to the stable log
- * (also in the pool) due to a fsync, O_DSYNC or other synchronous
- * requirement. In the event of a panic or power fail then those log
- * records (transactions) are replayed.
+ * The ZFS Intent Log (ZIL) saves "transaction records" (itxs) of system
+ * calls that change the file system. Each itx has enough information to
+ * be able to replay them after a system crash, power loss, or
+ * equivalent failure mode. These are stored in memory until either:
*
- * There is one ZIL per file system. Its on-disk (pool) format consists
- * of 3 parts:
+ * 1. they are committed to the pool by the DMU transaction group
+ * (txg), at which point they can be discarded; or
+ * 2. they are committed to the on-disk ZIL for the dataset being
+ * modified (e.g. due to an fsync, O_DSYNC, or other synchronous
+ * requirement).
*
- * - ZIL header
- * - ZIL blocks
- * - ZIL records
+ * In the event of a crash or power loss, the itxs contained by each
+ * dataset's on-disk ZIL will be replayed when that dataset is first
+ * instantiated (e.g. if the dataset is a normal fileystem, when it is
+ * first mounted).
*
- * A log record holds a system call transaction. Log blocks can
- * hold many log records and the blocks are chained together.
- * Each ZIL block contains a block pointer (blkptr_t) to the next
- * ZIL block in the chain. The ZIL header points to the first
- * block in the chain. Note there is not a fixed place in the pool
- * to hold blocks. They are dynamically allocated and freed as
- * needed from the blocks available. Figure X shows the ZIL structure:
+ * As hinted at above, there is one ZIL per dataset (both the in-memory
+ * representation, and the on-disk representation). The on-disk format
+ * consists of 3 parts:
+ *
+ * - a single, per-dataset, ZIL header; which points to a chain of
+ * - zero or more ZIL blocks; each of which contains
+ * - zero or more ZIL records
+ *
+ * A ZIL record holds the information necessary to replay a single
+ * system call transaction. A ZIL block can hold many ZIL records, and
+ * the blocks are chained together, similarly to a singly linked list.
+ *
+ * Each ZIL block contains a block pointer (blkptr_t) to the next ZIL
+ * block in the chain, and the ZIL header points to the first block in
+ * the chain.
+ *
+ * Note, there is not a fixed place in the pool to hold these ZIL
+ * blocks; they are dynamically allocated and freed as needed from the
+ * blocks available on the pool, though they can be preferentially
+ * allocated from a dedicated "log" vdev.
*/
+/*
+ * This controls the amount of time that a ZIL block (lwb) will remain
+ * "open" when it isn't "full", and it has a thread waiting for it to be
+ * committed to stable storage. Please refer to the zil_commit_waiter()
+ * function (and the comments within it) for more details.
+ */
+int zfs_commit_timeout_pct = 5;
+
/*
* See zil.h for more information about these fields.
*/
zil_stats_t zil_stats = {
- { "zil_commit_count", KSTAT_DATA_UINT64 },
- { "zil_commit_writer_count", KSTAT_DATA_UINT64 },
- { "zil_itx_count", KSTAT_DATA_UINT64 },
- { "zil_itx_indirect_count", KSTAT_DATA_UINT64 },
- { "zil_itx_indirect_bytes", KSTAT_DATA_UINT64 },
- { "zil_itx_copied_count", KSTAT_DATA_UINT64 },
- { "zil_itx_copied_bytes", KSTAT_DATA_UINT64 },
- { "zil_itx_needcopy_count", KSTAT_DATA_UINT64 },
- { "zil_itx_needcopy_bytes", KSTAT_DATA_UINT64 },
- { "zil_itx_metaslab_normal_count", KSTAT_DATA_UINT64 },
- { "zil_itx_metaslab_normal_bytes", KSTAT_DATA_UINT64 },
- { "zil_itx_metaslab_slog_count", KSTAT_DATA_UINT64 },
- { "zil_itx_metaslab_slog_bytes", KSTAT_DATA_UINT64 },
+ { "zil_commit_count", KSTAT_DATA_UINT64 },
+ { "zil_commit_writer_count", KSTAT_DATA_UINT64 },
+ { "zil_itx_count", KSTAT_DATA_UINT64 },
+ { "zil_itx_indirect_count", KSTAT_DATA_UINT64 },
+ { "zil_itx_indirect_bytes", KSTAT_DATA_UINT64 },
+ { "zil_itx_copied_count", KSTAT_DATA_UINT64 },
+ { "zil_itx_copied_bytes", KSTAT_DATA_UINT64 },
+ { "zil_itx_needcopy_count", KSTAT_DATA_UINT64 },
+ { "zil_itx_needcopy_bytes", KSTAT_DATA_UINT64 },
+ { "zil_itx_metaslab_normal_count", KSTAT_DATA_UINT64 },
+ { "zil_itx_metaslab_normal_bytes", KSTAT_DATA_UINT64 },
+ { "zil_itx_metaslab_slog_count", KSTAT_DATA_UINT64 },
+ { "zil_itx_metaslab_slog_bytes", KSTAT_DATA_UINT64 },
};
static kstat_t *zil_ksp;
/*
- * This global ZIL switch affects all pools
+ * Disable intent logging replay. This global ZIL switch affects all pools.
+ */
+int zil_replay_disable = 0;
+
+/*
+ * Disable the DKIOCFLUSHWRITECACHE commands that are normally sent to
+ * the disk(s) by the ZIL after an LWB write has completed. Setting this
+ * will cause ZIL corruption on power loss if a volatile out-of-order
+ * write cache is enabled.
*/
-int zil_replay_disable = 0; /* disable intent logging replay */
+int zil_nocacheflush = 0;
/*
- * Tunable parameter for debugging or performance analysis. Setting
- * zfs_nocacheflush will cause corruption on power loss if a volatile
- * out-of-order write cache is enabled.
+ * Limit SLOG write size per commit executed with synchronous priority.
+ * Any writes above that will be executed with lower (asynchronous) priority
+ * to limit potential SLOG device abuse by single active ZIL writer.
*/
-int zfs_nocacheflush = 0;
+unsigned long zil_slog_bulk = 768 * 1024;
static kmem_cache_t *zil_lwb_cache;
+static kmem_cache_t *zil_zcw_cache;
static void zil_async_to_sync(zilog_t *zilog, uint64_t foid);
#define LWB_EMPTY(lwb) ((BP_GET_LSIZE(&lwb->lwb_blk) - \
sizeof (zil_chain_t)) == (lwb->lwb_sz - lwb->lwb_nused))
-
-/*
- * ziltest is by and large an ugly hack, but very useful in
- * checking replay without tedious work.
- * When running ziltest we want to keep all itx's and so maintain
- * a single list in the zl_itxg[] that uses a high txg: ZILTEST_TXG
- * We subtract TXG_CONCURRENT_STATES to allow for common code.
- */
-#define ZILTEST_TXG (UINT64_MAX - TXG_CONCURRENT_STATES)
-
static int
zil_bp_compare(const void *x1, const void *x2)
{
const dva_t *dva1 = &((zil_bp_node_t *)x1)->zn_dva;
const dva_t *dva2 = &((zil_bp_node_t *)x2)->zn_dva;
- if (DVA_GET_VDEV(dva1) < DVA_GET_VDEV(dva2))
- return (-1);
- if (DVA_GET_VDEV(dva1) > DVA_GET_VDEV(dva2))
- return (1);
-
- if (DVA_GET_OFFSET(dva1) < DVA_GET_OFFSET(dva2))
- return (-1);
- if (DVA_GET_OFFSET(dva1) > DVA_GET_OFFSET(dva2))
- return (1);
+ int cmp = AVL_CMP(DVA_GET_VDEV(dva1), DVA_GET_VDEV(dva2));
+ if (likely(cmp))
+ return (cmp);
- return (0);
+ return (AVL_CMP(DVA_GET_OFFSET(dva1), DVA_GET_OFFSET(dva2)));
}
static void
zil_bp_tree_add(zilog_t *zilog, const blkptr_t *bp)
{
avl_tree_t *t = &zilog->zl_bp_tree;
- const dva_t *dva = BP_IDENTITY(bp);
+ const dva_t *dva;
zil_bp_node_t *zn;
avl_index_t where;
+ if (BP_IS_EMBEDDED(bp))
+ return (0);
+
+ dva = BP_IDENTITY(bp);
+
if (avl_find(t, dva, &where) != NULL)
- return (EEXIST);
+ return (SET_ERROR(EEXIST));
- zn = kmem_alloc(sizeof (zil_bp_node_t), KM_PUSHPAGE);
+ zn = kmem_alloc(sizeof (zil_bp_node_t), KM_SLEEP);
zn->zn_dva = *dva;
avl_insert(t, zn, where);
* Read a log block and make sure it's valid.
*/
static int
-zil_read_log_block(zilog_t *zilog, const blkptr_t *bp, blkptr_t *nbp, void *dst,
- char **end)
+zil_read_log_block(zilog_t *zilog, boolean_t decrypt, const blkptr_t *bp,
+ blkptr_t *nbp, void *dst, char **end)
{
enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
- uint32_t aflags = ARC_WAIT;
+ arc_flags_t aflags = ARC_FLAG_WAIT;
arc_buf_t *abuf = NULL;
- zbookmark_t zb;
+ zbookmark_phys_t zb;
int error;
if (zilog->zl_header->zh_claim_txg == 0)
if (!(zilog->zl_header->zh_flags & ZIL_CLAIM_LR_SEQ_VALID))
zio_flags |= ZIO_FLAG_SPECULATIVE;
+ if (!decrypt)
+ zio_flags |= ZIO_FLAG_RAW;
+
SET_BOOKMARK(&zb, bp->blk_cksum.zc_word[ZIL_ZC_OBJSET],
ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
- error = dsl_read_nolock(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
- ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
+ error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func,
+ &abuf, ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
if (error == 0) {
zio_cksum_t cksum = bp->blk_cksum;
if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk)) {
- error = ECKSUM;
+ error = SET_ERROR(ECKSUM);
} else {
+ ASSERT3U(len, <=, SPA_OLD_MAXBLOCKSIZE);
bcopy(lr, dst, len);
*end = (char *)dst + len;
*nbp = zilc->zc_next_blk;
if (bcmp(&cksum, &zilc->zc_next_blk.blk_cksum,
sizeof (cksum)) || BP_IS_HOLE(&zilc->zc_next_blk) ||
(zilc->zc_nused > (size - sizeof (*zilc)))) {
- error = ECKSUM;
+ error = SET_ERROR(ECKSUM);
} else {
+ ASSERT3U(zilc->zc_nused, <=,
+ SPA_OLD_MAXBLOCKSIZE);
bcopy(lr, dst, zilc->zc_nused);
*end = (char *)dst + zilc->zc_nused;
*nbp = zilc->zc_next_blk;
}
}
- VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1);
+ arc_buf_destroy(abuf, &abuf);
}
return (error);
{
enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
const blkptr_t *bp = &lr->lr_blkptr;
- uint32_t aflags = ARC_WAIT;
+ arc_flags_t aflags = ARC_FLAG_WAIT;
arc_buf_t *abuf = NULL;
- zbookmark_t zb;
+ zbookmark_phys_t zb;
int error;
if (BP_IS_HOLE(bp)) {
if (zilog->zl_header->zh_claim_txg == 0)
zio_flags |= ZIO_FLAG_SPECULATIVE | ZIO_FLAG_SCRUB;
+ /*
+ * If we are not using the resulting data, we are just checking that
+ * it hasn't been corrupted so we don't need to waste CPU time
+ * decompressing and decrypting it.
+ */
+ if (wbuf == NULL)
+ zio_flags |= ZIO_FLAG_RAW;
+
SET_BOOKMARK(&zb, dmu_objset_id(zilog->zl_os), lr->lr_foid,
ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
- error = arc_read_nolock(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
+ error = arc_read(NULL, zilog->zl_spa, bp, arc_getbuf_func, &abuf,
ZIO_PRIORITY_SYNC_READ, zio_flags, &aflags, &zb);
if (error == 0) {
if (wbuf != NULL)
bcopy(abuf->b_data, wbuf, arc_buf_size(abuf));
- (void) arc_buf_remove_ref(abuf, &abuf);
+ arc_buf_destroy(abuf, &abuf);
}
return (error);
*/
int
zil_parse(zilog_t *zilog, zil_parse_blk_func_t *parse_blk_func,
- zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg)
+ zil_parse_lr_func_t *parse_lr_func, void *arg, uint64_t txg,
+ boolean_t decrypt)
{
const zil_header_t *zh = zilog->zl_header;
boolean_t claimed = !!zh->zh_claim_txg;
char *lrbuf, *lrp;
int error = 0;
- bzero(&next_blk, sizeof(blkptr_t));
+ bzero(&next_blk, sizeof (blkptr_t));
/*
* Old logs didn't record the maximum zh_claim_lr_seq.
* If the log has been claimed, stop if we encounter a sequence
* number greater than the highest claimed sequence number.
*/
- lrbuf = zio_buf_alloc(SPA_MAXBLOCKSIZE);
+ lrbuf = zio_buf_alloc(SPA_OLD_MAXBLOCKSIZE);
zil_bp_tree_init(zilog);
for (blk = zh->zh_log; !BP_IS_HOLE(&blk); blk = next_blk) {
if (blk_seq > claim_blk_seq)
break;
- if ((error = parse_blk_func(zilog, &blk, arg, txg)) != 0)
+
+ error = parse_blk_func(zilog, &blk, arg, txg);
+ if (error != 0)
break;
ASSERT3U(max_blk_seq, <, blk_seq);
max_blk_seq = blk_seq;
if (max_lr_seq == claim_lr_seq && max_blk_seq == claim_blk_seq)
break;
- error = zil_read_log_block(zilog, &blk, &next_blk, lrbuf, &end);
- if (error)
+ error = zil_read_log_block(zilog, decrypt, &blk, &next_blk,
+ lrbuf, &end);
+ if (error != 0)
break;
for (lrp = lrbuf; lrp < end; lrp += reclen) {
ASSERT3U(reclen, >=, sizeof (lr_t));
if (lr->lrc_seq > claim_lr_seq)
goto done;
- if ((error = parse_lr_func(zilog, lr, arg, txg)) != 0)
+
+ error = parse_lr_func(zilog, lr, arg, txg);
+ if (error != 0)
goto done;
ASSERT3U(max_lr_seq, <, lr->lrc_seq);
max_lr_seq = lr->lrc_seq;
zilog->zl_parse_lr_count = lr_count;
ASSERT(!claimed || !(zh->zh_flags & ZIL_CLAIM_LR_SEQ_VALID) ||
- (max_blk_seq == claim_blk_seq && max_lr_seq == claim_lr_seq));
+ (max_blk_seq == claim_blk_seq && max_lr_seq == claim_lr_seq) ||
+ (decrypt && error == EIO));
zil_bp_tree_fini(zilog);
- zio_buf_free(lrbuf, SPA_MAXBLOCKSIZE);
+ zio_buf_free(lrbuf, SPA_OLD_MAXBLOCKSIZE);
return (error);
}
+/* ARGSUSED */
+static int
+zil_clear_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg)
+{
+ ASSERT(!BP_IS_HOLE(bp));
+
+ /*
+ * As we call this function from the context of a rewind to a
+ * checkpoint, each ZIL block whose txg is later than the txg
+ * that we rewind to is invalid. Thus, we return -1 so
+ * zil_parse() doesn't attempt to read it.
+ */
+ if (bp->blk_birth >= first_txg)
+ return (-1);
+
+ if (zil_bp_tree_add(zilog, bp) != 0)
+ return (0);
+
+ zio_free(zilog->zl_spa, first_txg, bp);
+ return (0);
+}
+
+/* ARGSUSED */
+static int
+zil_noop_log_record(zilog_t *zilog, lr_t *lrc, void *tx, uint64_t first_txg)
+{
+ return (0);
+}
+
static int
zil_claim_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t first_txg)
{
* Claim log block if not already committed and not already claimed.
* If tx == NULL, just verify that the block is claimable.
*/
- if (bp->blk_birth < first_txg || zil_bp_tree_add(zilog, bp) != 0)
+ if (BP_IS_HOLE(bp) || bp->blk_birth < first_txg ||
+ zil_bp_tree_add(zilog, bp) != 0)
return (0);
return (zio_wait(zio_claim(NULL, zilog->zl_spa,
* waited for all writes to be stable first), so it is semantically
* correct to declare this the end of the log.
*/
- if (lr->lr_blkptr.blk_birth >= first_txg &&
- (error = zil_read_log_data(zilog, lr, NULL)) != 0)
- return (error);
+ if (lr->lr_blkptr.blk_birth >= first_txg) {
+ error = zil_read_log_data(zilog, lr, NULL);
+ if (error != 0)
+ return (error);
+ }
+
return (zil_claim_log_block(zilog, &lr->lr_blkptr, tx, first_txg));
}
static int
zil_free_log_block(zilog_t *zilog, blkptr_t *bp, void *tx, uint64_t claim_txg)
{
- zio_free_zil(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
+ zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
return (0);
}
* If we previously claimed it, we need to free it.
*/
if (claim_txg != 0 && lrc->lrc_txtype == TX_WRITE &&
- bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0)
+ bp->blk_birth >= claim_txg && zil_bp_tree_add(zilog, bp) == 0 &&
+ !BP_IS_HOLE(bp))
zio_free(zilog->zl_spa, dmu_tx_get_txg(tx), bp);
return (0);
}
+static int
+zil_lwb_vdev_compare(const void *x1, const void *x2)
+{
+ const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev;
+ const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev;
+
+ return (AVL_CMP(v1, v2));
+}
+
static lwb_t *
-zil_alloc_lwb(zilog_t *zilog, blkptr_t *bp, uint64_t txg, boolean_t fastwrite)
+zil_alloc_lwb(zilog_t *zilog, blkptr_t *bp, boolean_t slog, uint64_t txg,
+ boolean_t fastwrite)
{
lwb_t *lwb;
- lwb = kmem_cache_alloc(zil_lwb_cache, KM_PUSHPAGE);
+ lwb = kmem_cache_alloc(zil_lwb_cache, KM_SLEEP);
lwb->lwb_zilog = zilog;
lwb->lwb_blk = *bp;
lwb->lwb_fastwrite = fastwrite;
+ lwb->lwb_slog = slog;
+ lwb->lwb_state = LWB_STATE_CLOSED;
lwb->lwb_buf = zio_buf_alloc(BP_GET_LSIZE(bp));
lwb->lwb_max_txg = txg;
- lwb->lwb_zio = NULL;
+ lwb->lwb_write_zio = NULL;
+ lwb->lwb_root_zio = NULL;
lwb->lwb_tx = NULL;
+ lwb->lwb_issued_timestamp = 0;
if (BP_GET_CHECKSUM(bp) == ZIO_CHECKSUM_ZILOG2) {
lwb->lwb_nused = sizeof (zil_chain_t);
lwb->lwb_sz = BP_GET_LSIZE(bp);
list_insert_tail(&zilog->zl_lwb_list, lwb);
mutex_exit(&zilog->zl_lock);
+ ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock));
+ ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
+ VERIFY(list_is_empty(&lwb->lwb_waiters));
+ VERIFY(list_is_empty(&lwb->lwb_itxs));
+
return (lwb);
}
+static void
+zil_free_lwb(zilog_t *zilog, lwb_t *lwb)
+{
+ ASSERT(MUTEX_HELD(&zilog->zl_lock));
+ ASSERT(!MUTEX_HELD(&lwb->lwb_vdev_lock));
+ VERIFY(list_is_empty(&lwb->lwb_waiters));
+ VERIFY(list_is_empty(&lwb->lwb_itxs));
+ ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
+ ASSERT3P(lwb->lwb_write_zio, ==, NULL);
+ ASSERT3P(lwb->lwb_root_zio, ==, NULL);
+ ASSERT3U(lwb->lwb_max_txg, <=, spa_syncing_txg(zilog->zl_spa));
+ ASSERT(lwb->lwb_state == LWB_STATE_CLOSED ||
+ lwb->lwb_state == LWB_STATE_FLUSH_DONE);
+
+ /*
+ * Clear the zilog's field to indicate this lwb is no longer
+ * valid, and prevent use-after-free errors.
+ */
+ if (zilog->zl_last_lwb_opened == lwb)
+ zilog->zl_last_lwb_opened = NULL;
+
+ kmem_cache_free(zil_lwb_cache, lwb);
+}
+
/*
* Called when we create in-memory log transactions so that we know
* to cleanup the itxs at the end of spa_sync().
dsl_pool_t *dp = zilog->zl_dmu_pool;
dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
- if (dsl_dataset_is_snapshot(ds))
+ ASSERT(spa_writeable(zilog->zl_spa));
+
+ if (ds->ds_is_snapshot)
panic("dirtying snapshot!");
- if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg) == 0) {
+ if (txg_list_add(&dp->dp_dirty_zilogs, zilog, txg)) {
/* up the hold count until we can be written out */
dmu_buf_add_ref(ds->ds_dbuf, zilog);
+
+ zilog->zl_dirty_max_txg = MAX(txg, zilog->zl_dirty_max_txg);
}
}
+/*
+ * Determine if the zil is dirty in the specified txg. Callers wanting to
+ * ensure that the dirty state does not change must hold the itxg_lock for
+ * the specified txg. Holding the lock will ensure that the zil cannot be
+ * dirtied (zil_itx_assign) or cleaned (zil_clean) while we check its current
+ * state.
+ */
+boolean_t
+zilog_is_dirty_in_txg(zilog_t *zilog, uint64_t txg)
+{
+ dsl_pool_t *dp = zilog->zl_dmu_pool;
+
+ if (txg_list_member(&dp->dp_dirty_zilogs, zilog, txg & TXG_MASK))
+ return (B_TRUE);
+ return (B_FALSE);
+}
+
+/*
+ * Determine if the zil is dirty. The zil is considered dirty if it has
+ * any pending itx records that have not been cleaned by zil_clean().
+ */
boolean_t
zilog_is_dirty(zilog_t *zilog)
{
dsl_pool_t *dp = zilog->zl_dmu_pool;
- int t;
- for (t = 0; t < TXG_SIZE; t++) {
+ for (int t = 0; t < TXG_SIZE; t++) {
if (txg_list_member(&dp->dp_dirty_zilogs, zilog, t))
return (B_TRUE);
}
blkptr_t blk;
int error = 0;
boolean_t fastwrite = FALSE;
+ boolean_t slog = FALSE;
/*
* Wait for any previous destroy to complete.
/*
* Allocate an initial log block if:
* - there isn't one already
- * - the existing block is the wrong endianess
+ * - the existing block is the wrong endianness
*/
if (BP_IS_HOLE(&blk) || BP_SHOULD_BYTESWAP(&blk)) {
tx = dmu_tx_create(zilog->zl_os);
- VERIFY(dmu_tx_assign(tx, TXG_WAIT) == 0);
+ VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
txg = dmu_tx_get_txg(tx);
if (!BP_IS_HOLE(&blk)) {
- zio_free_zil(zilog->zl_spa, txg, &blk);
+ zio_free(zilog->zl_spa, txg, &blk);
BP_ZERO(&blk);
}
- error = zio_alloc_zil(zilog->zl_spa, txg, &blk,
- ZIL_MIN_BLKSZ, B_TRUE);
+ error = zio_alloc_zil(zilog->zl_spa, zilog->zl_os, txg, &blk,
+ ZIL_MIN_BLKSZ, &slog);
fastwrite = TRUE;
if (error == 0)
}
/*
- * Allocate a log write buffer (lwb) for the first log block.
+ * Allocate a log write block (lwb) for the first log block.
*/
if (error == 0)
- lwb = zil_alloc_lwb(zilog, &blk, txg, fastwrite);
+ lwb = zil_alloc_lwb(zilog, &blk, slog, txg, fastwrite);
/*
* If we just allocated the first log block, commit our transaction
- * and wait for zil_sync() to stuff the block poiner into zh_log.
+ * and wait for zil_sync() to stuff the block pointer into zh_log.
* (zh is part of the MOS, so we cannot modify it in open context.)
*/
if (tx != NULL) {
txg_wait_synced(zilog->zl_dmu_pool, txg);
}
- ASSERT(bcmp(&blk, &zh->zh_log, sizeof (blk)) == 0);
+ ASSERT(error != 0 || bcmp(&blk, &zh->zh_log, sizeof (blk)) == 0);
+ IMPLY(error == 0, lwb != NULL);
return (lwb);
}
/*
- * In one tx, free all log blocks and clear the log header.
- * If keep_first is set, then we're replaying a log with no content.
- * We want to keep the first block, however, so that the first
- * synchronous transaction doesn't require a txg_wait_synced()
- * in zil_create(). We don't need to txg_wait_synced() here either
- * when keep_first is set, because both zil_create() and zil_destroy()
- * will wait for any in-progress destroys to complete.
+ * In one tx, free all log blocks and clear the log header. If keep_first
+ * is set, then we're replaying a log with no content. We want to keep the
+ * first block, however, so that the first synchronous transaction doesn't
+ * require a txg_wait_synced() in zil_create(). We don't need to
+ * txg_wait_synced() here either when keep_first is set, because both
+ * zil_create() and zil_destroy() will wait for any in-progress destroys
+ * to complete.
*/
void
zil_destroy(zilog_t *zilog, boolean_t keep_first)
return;
tx = dmu_tx_create(zilog->zl_os);
- VERIFY(dmu_tx_assign(tx, TXG_WAIT) == 0);
+ VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
txg = dmu_tx_get_txg(tx);
ASSERT(zh->zh_claim_txg == 0);
VERIFY(!keep_first);
while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
- ASSERT(lwb->lwb_zio == NULL);
if (lwb->lwb_fastwrite)
metaslab_fastwrite_unmark(zilog->zl_spa,
&lwb->lwb_blk);
+
list_remove(&zilog->zl_lwb_list, lwb);
if (lwb->lwb_buf != NULL)
zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
- zio_free_zil(zilog->zl_spa, txg, &lwb->lwb_blk);
- kmem_cache_free(zil_lwb_cache, lwb);
+ zio_free(zilog->zl_spa, txg, &lwb->lwb_blk);
+ zil_free_lwb(zilog, lwb);
}
} else if (!keep_first) {
zil_destroy_sync(zilog, tx);
{
ASSERT(list_is_empty(&zilog->zl_lwb_list));
(void) zil_parse(zilog, zil_free_log_block,
- zil_free_log_record, tx, zilog->zl_header->zh_claim_txg);
+ zil_free_log_record, tx, zilog->zl_header->zh_claim_txg, B_FALSE);
}
int
-zil_claim(const char *osname, void *txarg)
+zil_claim(dsl_pool_t *dp, dsl_dataset_t *ds, void *txarg)
{
dmu_tx_t *tx = txarg;
- uint64_t first_txg = dmu_tx_get_txg(tx);
zilog_t *zilog;
+ uint64_t first_txg;
zil_header_t *zh;
objset_t *os;
int error;
- error = dmu_objset_hold(osname, FTAG, &os);
- if (error) {
- cmn_err(CE_WARN, "can't open objset for %s", osname);
+ error = dmu_objset_own_obj(dp, ds->ds_object,
+ DMU_OST_ANY, B_FALSE, B_FALSE, FTAG, &os);
+ if (error != 0) {
+ /*
+ * EBUSY indicates that the objset is inconsistent, in which
+ * case it can not have a ZIL.
+ */
+ if (error != EBUSY) {
+ cmn_err(CE_WARN, "can't open objset for %llu, error %u",
+ (unsigned long long)ds->ds_object, error);
+ }
+
return (0);
}
zilog = dmu_objset_zil(os);
zh = zil_header_in_syncing_context(zilog);
+ ASSERT3U(tx->tx_txg, ==, spa_first_txg(zilog->zl_spa));
+ first_txg = spa_min_claim_txg(zilog->zl_spa);
- if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR) {
- if (!BP_IS_HOLE(&zh->zh_log))
- zio_free_zil(zilog->zl_spa, first_txg, &zh->zh_log);
+ /*
+ * If the spa_log_state is not set to be cleared, check whether
+ * the current uberblock is a checkpoint one and if the current
+ * header has been claimed before moving on.
+ *
+ * If the current uberblock is a checkpointed uberblock then
+ * one of the following scenarios took place:
+ *
+ * 1] We are currently rewinding to the checkpoint of the pool.
+ * 2] We crashed in the middle of a checkpoint rewind but we
+ * did manage to write the checkpointed uberblock to the
+ * vdev labels, so when we tried to import the pool again
+ * the checkpointed uberblock was selected from the import
+ * procedure.
+ *
+ * In both cases we want to zero out all the ZIL blocks, except
+ * the ones that have been claimed at the time of the checkpoint
+ * (their zh_claim_txg != 0). The reason is that these blocks
+ * may be corrupted since we may have reused their locations on
+ * disk after we took the checkpoint.
+ *
+ * We could try to set spa_log_state to SPA_LOG_CLEAR earlier
+ * when we first figure out whether the current uberblock is
+ * checkpointed or not. Unfortunately, that would discard all
+ * the logs, including the ones that are claimed, and we would
+ * leak space.
+ */
+ if (spa_get_log_state(zilog->zl_spa) == SPA_LOG_CLEAR ||
+ (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 &&
+ zh->zh_claim_txg == 0)) {
+ if (!BP_IS_HOLE(&zh->zh_log)) {
+ (void) zil_parse(zilog, zil_clear_log_block,
+ zil_noop_log_record, tx, first_txg, B_FALSE);
+ }
BP_ZERO(&zh->zh_log);
+ if (os->os_encrypted)
+ os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;
dsl_dataset_dirty(dmu_objset_ds(os), tx);
- dmu_objset_rele(os, FTAG);
+ dmu_objset_disown(os, B_FALSE, FTAG);
return (0);
}
+ /*
+ * If we are not rewinding and opening the pool normally, then
+ * the min_claim_txg should be equal to the first txg of the pool.
+ */
+ ASSERT3U(first_txg, ==, spa_first_txg(zilog->zl_spa));
+
/*
* Claim all log blocks if we haven't already done so, and remember
* the highest claimed sequence number. This ensures that if we can
ASSERT3U(zh->zh_claim_txg, <=, first_txg);
if (zh->zh_claim_txg == 0 && !BP_IS_HOLE(&zh->zh_log)) {
(void) zil_parse(zilog, zil_claim_log_block,
- zil_claim_log_record, tx, first_txg);
+ zil_claim_log_record, tx, first_txg, B_FALSE);
zh->zh_claim_txg = first_txg;
zh->zh_claim_blk_seq = zilog->zl_parse_blk_seq;
zh->zh_claim_lr_seq = zilog->zl_parse_lr_seq;
if (zilog->zl_parse_lr_count || zilog->zl_parse_blk_count > 1)
zh->zh_flags |= ZIL_REPLAY_NEEDED;
zh->zh_flags |= ZIL_CLAIM_LR_SEQ_VALID;
+ if (os->os_encrypted)
+ os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;
dsl_dataset_dirty(dmu_objset_ds(os), tx);
}
ASSERT3U(first_txg, ==, (spa_last_synced_txg(zilog->zl_spa) + 1));
- dmu_objset_rele(os, FTAG);
+ dmu_objset_disown(os, B_FALSE, FTAG);
return (0);
}
* Checksum errors are ok as they indicate the end of the chain.
* Any other error (no device or read failure) returns an error.
*/
+/* ARGSUSED */
int
-zil_check_log_chain(const char *osname, void *tx)
+zil_check_log_chain(dsl_pool_t *dp, dsl_dataset_t *ds, void *tx)
{
zilog_t *zilog;
objset_t *os;
ASSERT(tx == NULL);
- error = dmu_objset_hold(osname, FTAG, &os);
- if (error) {
- cmn_err(CE_WARN, "can't open objset for %s", osname);
+ error = dmu_objset_from_ds(ds, &os);
+ if (error != 0) {
+ cmn_err(CE_WARN, "can't open objset %llu, error %d",
+ (unsigned long long)ds->ds_object, error);
return (0);
}
zilog = dmu_objset_zil(os);
bp = (blkptr_t *)&zilog->zl_header->zh_log;
- /*
- * Check the first block and determine if it's on a log device
- * which may have been removed or faulted prior to loading this
- * pool. If so, there's no point in checking the rest of the log
- * as its content should have already been synced to the pool.
- */
if (!BP_IS_HOLE(bp)) {
vdev_t *vd;
boolean_t valid = B_TRUE;
+ /*
+ * Check the first block and determine if it's on a log device
+ * which may have been removed or faulted prior to loading this
+ * pool. If so, there's no point in checking the rest of the
+ * log as its content should have already been synced to the
+ * pool.
+ */
spa_config_enter(os->os_spa, SCL_STATE, FTAG, RW_READER);
vd = vdev_lookup_top(os->os_spa, DVA_GET_VDEV(&bp->blk_dva[0]));
if (vd->vdev_islog && vdev_is_dead(vd))
valid = vdev_log_state_valid(vd);
spa_config_exit(os->os_spa, SCL_STATE, FTAG);
- if (!valid) {
- dmu_objset_rele(os, FTAG);
+ if (!valid)
+ return (0);
+
+ /*
+ * Check whether the current uberblock is checkpointed (e.g.
+ * we are rewinding) and whether the current header has been
+ * claimed or not. If it hasn't then skip verifying it. We
+ * do this because its ZIL blocks may be part of the pool's
+ * state before the rewind, which is no longer valid.
+ */
+ zil_header_t *zh = zil_header_in_syncing_context(zilog);
+ if (zilog->zl_spa->spa_uberblock.ub_checkpoint_txg != 0 &&
+ zh->zh_claim_txg == 0)
return (0);
- }
}
/*
* which will update spa_max_claim_txg. See spa_load() for details.
*/
error = zil_parse(zilog, zil_claim_log_block, zil_claim_log_record, tx,
- zilog->zl_header->zh_claim_txg ? -1ULL : spa_first_txg(os->os_spa));
-
- dmu_objset_rele(os, FTAG);
+ zilog->zl_header->zh_claim_txg ? -1ULL :
+ spa_min_claim_txg(os->os_spa), B_FALSE);
return ((error == ECKSUM || error == ENOENT) ? 0 : error);
}
-static int
-zil_vdev_compare(const void *x1, const void *x2)
+/*
+ * When an itx is "skipped", this function is used to properly mark the
+ * waiter as "done, and signal any thread(s) waiting on it. An itx can
+ * be skipped (and not committed to an lwb) for a variety of reasons,
+ * one of them being that the itx was committed via spa_sync(), prior to
+ * it being committed to an lwb; this can happen if a thread calling
+ * zil_commit() is racing with spa_sync().
+ */
+static void
+zil_commit_waiter_skip(zil_commit_waiter_t *zcw)
{
- const uint64_t v1 = ((zil_vdev_node_t *)x1)->zv_vdev;
- const uint64_t v2 = ((zil_vdev_node_t *)x2)->zv_vdev;
+ mutex_enter(&zcw->zcw_lock);
+ ASSERT3B(zcw->zcw_done, ==, B_FALSE);
+ zcw->zcw_done = B_TRUE;
+ cv_broadcast(&zcw->zcw_cv);
+ mutex_exit(&zcw->zcw_lock);
+}
- if (v1 < v2)
- return (-1);
- if (v1 > v2)
- return (1);
+/*
+ * This function is used when the given waiter is to be linked into an
+ * lwb's "lwb_waiter" list; i.e. when the itx is committed to the lwb.
+ * At this point, the waiter will no longer be referenced by the itx,
+ * and instead, will be referenced by the lwb.
+ */
+static void
+zil_commit_waiter_link_lwb(zil_commit_waiter_t *zcw, lwb_t *lwb)
+{
+ /*
+ * The lwb_waiters field of the lwb is protected by the zilog's
+ * zl_lock, thus it must be held when calling this function.
+ */
+ ASSERT(MUTEX_HELD(&lwb->lwb_zilog->zl_lock));
+
+ mutex_enter(&zcw->zcw_lock);
+ ASSERT(!list_link_active(&zcw->zcw_node));
+ ASSERT3P(zcw->zcw_lwb, ==, NULL);
+ ASSERT3P(lwb, !=, NULL);
+ ASSERT(lwb->lwb_state == LWB_STATE_OPENED ||
+ lwb->lwb_state == LWB_STATE_ISSUED ||
+ lwb->lwb_state == LWB_STATE_WRITE_DONE);
+
+ list_insert_tail(&lwb->lwb_waiters, zcw);
+ zcw->zcw_lwb = lwb;
+ mutex_exit(&zcw->zcw_lock);
+}
- return (0);
+/*
+ * This function is used when zio_alloc_zil() fails to allocate a ZIL
+ * block, and the given waiter must be linked to the "nolwb waiters"
+ * list inside of zil_process_commit_list().
+ */
+static void
+zil_commit_waiter_link_nolwb(zil_commit_waiter_t *zcw, list_t *nolwb)
+{
+ mutex_enter(&zcw->zcw_lock);
+ ASSERT(!list_link_active(&zcw->zcw_node));
+ ASSERT3P(zcw->zcw_lwb, ==, NULL);
+ list_insert_tail(nolwb, zcw);
+ mutex_exit(&zcw->zcw_lock);
}
void
-zil_add_block(zilog_t *zilog, const blkptr_t *bp)
+zil_lwb_add_block(lwb_t *lwb, const blkptr_t *bp)
{
- avl_tree_t *t = &zilog->zl_vdev_tree;
+ avl_tree_t *t = &lwb->lwb_vdev_tree;
avl_index_t where;
zil_vdev_node_t *zv, zvsearch;
int ndvas = BP_GET_NDVAS(bp);
int i;
- if (zfs_nocacheflush)
+ if (zil_nocacheflush)
return;
- ASSERT(zilog->zl_writer);
-
- /*
- * Even though we're zl_writer, we still need a lock because the
- * zl_get_data() callbacks may have dmu_sync() done callbacks
- * that will run concurrently.
- */
- mutex_enter(&zilog->zl_vdev_lock);
+ mutex_enter(&lwb->lwb_vdev_lock);
for (i = 0; i < ndvas; i++) {
zvsearch.zv_vdev = DVA_GET_VDEV(&bp->blk_dva[i]);
if (avl_find(t, &zvsearch, &where) == NULL) {
- zv = kmem_alloc(sizeof (*zv), KM_PUSHPAGE);
+ zv = kmem_alloc(sizeof (*zv), KM_SLEEP);
zv->zv_vdev = zvsearch.zv_vdev;
avl_insert(t, zv, where);
}
}
- mutex_exit(&zilog->zl_vdev_lock);
+ mutex_exit(&lwb->lwb_vdev_lock);
}
static void
-zil_flush_vdevs(zilog_t *zilog)
+zil_lwb_flush_defer(lwb_t *lwb, lwb_t *nlwb)
{
- spa_t *spa = zilog->zl_spa;
- avl_tree_t *t = &zilog->zl_vdev_tree;
+ avl_tree_t *src = &lwb->lwb_vdev_tree;
+ avl_tree_t *dst = &nlwb->lwb_vdev_tree;
void *cookie = NULL;
zil_vdev_node_t *zv;
- zio_t *zio;
- ASSERT(zilog->zl_writer);
+ ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
+ ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
+ ASSERT3S(nlwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
/*
- * We don't need zl_vdev_lock here because we're the zl_writer,
- * and all zl_get_data() callbacks are done.
+ * While 'lwb' is at a point in its lifetime where lwb_vdev_tree does
+ * not need the protection of lwb_vdev_lock (it will only be modified
+ * while holding zilog->zl_lock) as its writes and those of its
+ * children have all completed. The younger 'nlwb' may be waiting on
+ * future writes to additional vdevs.
*/
- if (avl_numnodes(t) == 0)
- return;
+ mutex_enter(&nlwb->lwb_vdev_lock);
+ /*
+ * Tear down the 'lwb' vdev tree, ensuring that entries which do not
+ * exist in 'nlwb' are moved to it, freeing any would-be duplicates.
+ */
+ while ((zv = avl_destroy_nodes(src, &cookie)) != NULL) {
+ avl_index_t where;
- spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
+ if (avl_find(dst, zv, &where) == NULL) {
+ avl_insert(dst, zv, where);
+ } else {
+ kmem_free(zv, sizeof (*zv));
+ }
+ }
+ mutex_exit(&nlwb->lwb_vdev_lock);
+}
- zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
+void
+zil_lwb_add_txg(lwb_t *lwb, uint64_t txg)
+{
+ lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg);
+}
- while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) {
- vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev);
- if (vd != NULL)
- zio_flush(zio, vd);
- kmem_free(zv, sizeof (*zv));
- }
+/*
+ * This function is a called after all vdevs associated with a given lwb
+ * write have completed their DKIOCFLUSHWRITECACHE command; or as soon
+ * as the lwb write completes, if "zil_nocacheflush" is set. Further,
+ * all "previous" lwb's will have completed before this function is
+ * called; i.e. this function is called for all previous lwbs before
+ * it's called for "this" lwb (enforced via zio the dependencies
+ * configured in zil_lwb_set_zio_dependency()).
+ *
+ * The intention is for this function to be called as soon as the
+ * contents of an lwb are considered "stable" on disk, and will survive
+ * any sudden loss of power. At this point, any threads waiting for the
+ * lwb to reach this state are signalled, and the "waiter" structures
+ * are marked "done".
+ */
+static void
+zil_lwb_flush_vdevs_done(zio_t *zio)
+{
+ lwb_t *lwb = zio->io_private;
+ zilog_t *zilog = lwb->lwb_zilog;
+ dmu_tx_t *tx = lwb->lwb_tx;
+ zil_commit_waiter_t *zcw;
+ itx_t *itx;
+
+ spa_config_exit(zilog->zl_spa, SCL_STATE, lwb);
+
+ zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
+
+ mutex_enter(&zilog->zl_lock);
/*
- * Wait for all the flushes to complete. Not all devices actually
- * support the DKIOCFLUSHWRITECACHE ioctl, so it's OK if it fails.
+ * Ensure the lwb buffer pointer is cleared before releasing the
+ * txg. If we have had an allocation failure and the txg is
+ * waiting to sync then we want zil_sync() to remove the lwb so
+ * that it's not picked up as the next new one in
+ * zil_process_commit_list(). zil_sync() will only remove the
+ * lwb if lwb_buf is null.
*/
- (void) zio_wait(zio);
+ lwb->lwb_buf = NULL;
+ lwb->lwb_tx = NULL;
+
+ ASSERT3U(lwb->lwb_issued_timestamp, >, 0);
+ zilog->zl_last_lwb_latency = gethrtime() - lwb->lwb_issued_timestamp;
+
+ lwb->lwb_root_zio = NULL;
+
+ ASSERT3S(lwb->lwb_state, ==, LWB_STATE_WRITE_DONE);
+ lwb->lwb_state = LWB_STATE_FLUSH_DONE;
+
+ if (zilog->zl_last_lwb_opened == lwb) {
+ /*
+ * Remember the highest committed log sequence number
+ * for ztest. We only update this value when all the log
+ * writes succeeded, because ztest wants to ASSERT that
+ * it got the whole log chain.
+ */
+ zilog->zl_commit_lr_seq = zilog->zl_lr_seq;
+ }
+
+ while ((itx = list_head(&lwb->lwb_itxs)) != NULL) {
+ list_remove(&lwb->lwb_itxs, itx);
+ zil_itx_destroy(itx);
+ }
+
+ while ((zcw = list_head(&lwb->lwb_waiters)) != NULL) {
+ mutex_enter(&zcw->zcw_lock);
+
+ ASSERT(list_link_active(&zcw->zcw_node));
+ list_remove(&lwb->lwb_waiters, zcw);
- spa_config_exit(spa, SCL_STATE, FTAG);
+ ASSERT3P(zcw->zcw_lwb, ==, lwb);
+ zcw->zcw_lwb = NULL;
+
+ zcw->zcw_zio_error = zio->io_error;
+
+ ASSERT3B(zcw->zcw_done, ==, B_FALSE);
+ zcw->zcw_done = B_TRUE;
+ cv_broadcast(&zcw->zcw_cv);
+
+ mutex_exit(&zcw->zcw_lock);
+ }
+
+ mutex_exit(&zilog->zl_lock);
+
+ /*
+ * Now that we've written this log block, we have a stable pointer
+ * to the next block in the chain, so it's OK to let the txg in
+ * which we allocated the next block sync.
+ */
+ dmu_tx_commit(tx);
}
/*
- * Function called when a log block write completes
+ * This is called when an lwb's write zio completes. The callback's
+ * purpose is to issue the DKIOCFLUSHWRITECACHE commands for the vdevs
+ * in the lwb's lwb_vdev_tree. The tree will contain the vdevs involved
+ * in writing out this specific lwb's data, and in the case that cache
+ * flushes have been deferred, vdevs involved in writing the data for
+ * previous lwbs. The writes corresponding to all the vdevs in the
+ * lwb_vdev_tree will have completed by the time this is called, due to
+ * the zio dependencies configured in zil_lwb_set_zio_dependency(),
+ * which takes deferred flushes into account. The lwb will be "done"
+ * once zil_lwb_flush_vdevs_done() is called, which occurs in the zio
+ * completion callback for the lwb's root zio.
*/
static void
zil_lwb_write_done(zio_t *zio)
{
lwb_t *lwb = zio->io_private;
+ spa_t *spa = zio->io_spa;
zilog_t *zilog = lwb->lwb_zilog;
- dmu_tx_t *tx = lwb->lwb_tx;
+ avl_tree_t *t = &lwb->lwb_vdev_tree;
+ void *cookie = NULL;
+ zil_vdev_node_t *zv;
+ lwb_t *nlwb;
+
+ ASSERT3S(spa_config_held(spa, SCL_STATE, RW_READER), !=, 0);
ASSERT(BP_GET_COMPRESS(zio->io_bp) == ZIO_COMPRESS_OFF);
ASSERT(BP_GET_TYPE(zio->io_bp) == DMU_OT_INTENT_LOG);
ASSERT(BP_GET_BYTEORDER(zio->io_bp) == ZFS_HOST_BYTEORDER);
ASSERT(!BP_IS_GANG(zio->io_bp));
ASSERT(!BP_IS_HOLE(zio->io_bp));
- ASSERT(zio->io_bp->blk_fill == 0);
+ ASSERT(BP_GET_FILL(zio->io_bp) == 0);
+
+ abd_put(zio->io_abd);
- /*
- * Ensure the lwb buffer pointer is cleared before releasing
- * the txg. If we have had an allocation failure and
- * the txg is waiting to sync then we want want zil_sync()
- * to remove the lwb so that it's not picked up as the next new
- * one in zil_commit_writer(). zil_sync() will only remove
- * the lwb if lwb_buf is null.
- */
- zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
mutex_enter(&zilog->zl_lock);
- lwb->lwb_zio = NULL;
+ ASSERT3S(lwb->lwb_state, ==, LWB_STATE_ISSUED);
+ lwb->lwb_state = LWB_STATE_WRITE_DONE;
+ lwb->lwb_write_zio = NULL;
lwb->lwb_fastwrite = FALSE;
- lwb->lwb_buf = NULL;
- lwb->lwb_tx = NULL;
+ nlwb = list_next(&zilog->zl_lwb_list, lwb);
mutex_exit(&zilog->zl_lock);
+ if (avl_numnodes(t) == 0)
+ return;
+
/*
- * Now that we've written this log block, we have a stable pointer
- * to the next block in the chain, so it's OK to let the txg in
- * which we allocated the next block sync.
+ * If there was an IO error, we're not going to call zio_flush()
+ * on these vdevs, so we simply empty the tree and free the
+ * nodes. We avoid calling zio_flush() since there isn't any
+ * good reason for doing so, after the lwb block failed to be
+ * written out.
*/
- dmu_tx_commit(tx);
+ if (zio->io_error != 0) {
+ while ((zv = avl_destroy_nodes(t, &cookie)) != NULL)
+ kmem_free(zv, sizeof (*zv));
+ return;
+ }
+
+ /*
+ * If this lwb does not have any threads waiting for it to
+ * complete, we want to defer issuing the DKIOCFLUSHWRITECACHE
+ * command to the vdevs written to by "this" lwb, and instead
+ * rely on the "next" lwb to handle the DKIOCFLUSHWRITECACHE
+ * command for those vdevs. Thus, we merge the vdev tree of
+ * "this" lwb with the vdev tree of the "next" lwb in the list,
+ * and assume the "next" lwb will handle flushing the vdevs (or
+ * deferring the flush(s) again).
+ *
+ * This is a useful performance optimization, especially for
+ * workloads with lots of async write activity and few sync
+ * write and/or fsync activity, as it has the potential to
+ * coalesce multiple flush commands to a vdev into one.
+ */
+ if (list_head(&lwb->lwb_waiters) == NULL && nlwb != NULL) {
+ zil_lwb_flush_defer(lwb, nlwb);
+ ASSERT(avl_is_empty(&lwb->lwb_vdev_tree));
+ return;
+ }
+
+ while ((zv = avl_destroy_nodes(t, &cookie)) != NULL) {
+ vdev_t *vd = vdev_lookup_top(spa, zv->zv_vdev);
+ if (vd != NULL)
+ zio_flush(lwb->lwb_root_zio, vd);
+ kmem_free(zv, sizeof (*zv));
+ }
+}
+
+static void
+zil_lwb_set_zio_dependency(zilog_t *zilog, lwb_t *lwb)
+{
+ lwb_t *last_lwb_opened = zilog->zl_last_lwb_opened;
+
+ ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
+ ASSERT(MUTEX_HELD(&zilog->zl_lock));
+
+ /*
+ * The zilog's "zl_last_lwb_opened" field is used to build the
+ * lwb/zio dependency chain, which is used to preserve the
+ * ordering of lwb completions that is required by the semantics
+ * of the ZIL. Each new lwb zio becomes a parent of the
+ * "previous" lwb zio, such that the new lwb's zio cannot
+ * complete until the "previous" lwb's zio completes.
+ *
+ * This is required by the semantics of zil_commit(); the commit
+ * waiters attached to the lwbs will be woken in the lwb zio's
+ * completion callback, so this zio dependency graph ensures the
+ * waiters are woken in the correct order (the same order the
+ * lwbs were created).
+ */
+ if (last_lwb_opened != NULL &&
+ last_lwb_opened->lwb_state != LWB_STATE_FLUSH_DONE) {
+ ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED ||
+ last_lwb_opened->lwb_state == LWB_STATE_ISSUED ||
+ last_lwb_opened->lwb_state == LWB_STATE_WRITE_DONE);
+
+ ASSERT3P(last_lwb_opened->lwb_root_zio, !=, NULL);
+ zio_add_child(lwb->lwb_root_zio,
+ last_lwb_opened->lwb_root_zio);
+
+ /*
+ * If the previous lwb's write hasn't already completed,
+ * we also want to order the completion of the lwb write
+ * zios (above, we only order the completion of the lwb
+ * root zios). This is required because of how we can
+ * defer the DKIOCFLUSHWRITECACHE commands for each lwb.
+ *
+ * When the DKIOCFLUSHWRITECACHE commands are deferred,
+ * the previous lwb will rely on this lwb to flush the
+ * vdevs written to by that previous lwb. Thus, we need
+ * to ensure this lwb doesn't issue the flush until
+ * after the previous lwb's write completes. We ensure
+ * this ordering by setting the zio parent/child
+ * relationship here.
+ *
+ * Without this relationship on the lwb's write zio,
+ * it's possible for this lwb's write to complete prior
+ * to the previous lwb's write completing; and thus, the
+ * vdevs for the previous lwb would be flushed prior to
+ * that lwb's data being written to those vdevs (the
+ * vdevs are flushed in the lwb write zio's completion
+ * handler, zil_lwb_write_done()).
+ */
+ if (last_lwb_opened->lwb_state != LWB_STATE_WRITE_DONE) {
+ ASSERT(last_lwb_opened->lwb_state == LWB_STATE_OPENED ||
+ last_lwb_opened->lwb_state == LWB_STATE_ISSUED);
+
+ ASSERT3P(last_lwb_opened->lwb_write_zio, !=, NULL);
+ zio_add_child(lwb->lwb_write_zio,
+ last_lwb_opened->lwb_write_zio);
+ }
+ }
}
+
/*
- * Initialize the io for a log block.
+ * This function's purpose is to "open" an lwb such that it is ready to
+ * accept new itxs being committed to it. To do this, the lwb's zio
+ * structures are created, and linked to the lwb. This function is
+ * idempotent; if the passed in lwb has already been opened, this
+ * function is essentially a no-op.
*/
static void
-zil_lwb_write_init(zilog_t *zilog, lwb_t *lwb)
+zil_lwb_write_open(zilog_t *zilog, lwb_t *lwb)
{
- zbookmark_t zb;
+ zbookmark_phys_t zb;
+ zio_priority_t prio;
+
+ ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
+ ASSERT3P(lwb, !=, NULL);
+ EQUIV(lwb->lwb_root_zio == NULL, lwb->lwb_state == LWB_STATE_CLOSED);
+ EQUIV(lwb->lwb_root_zio != NULL, lwb->lwb_state == LWB_STATE_OPENED);
SET_BOOKMARK(&zb, lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_OBJSET],
ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
lwb->lwb_blk.blk_cksum.zc_word[ZIL_ZC_SEQ]);
- if (zilog->zl_root_zio == NULL) {
- zilog->zl_root_zio = zio_root(zilog->zl_spa, NULL, NULL,
- ZIO_FLAG_CANFAIL);
- }
-
/* Lock so zil_sync() doesn't fastwrite_unmark after zio is created */
mutex_enter(&zilog->zl_lock);
- if (lwb->lwb_zio == NULL) {
+ if (lwb->lwb_root_zio == NULL) {
+ abd_t *lwb_abd = abd_get_from_buf(lwb->lwb_buf,
+ BP_GET_LSIZE(&lwb->lwb_blk));
+
if (!lwb->lwb_fastwrite) {
metaslab_fastwrite_mark(zilog->zl_spa, &lwb->lwb_blk);
lwb->lwb_fastwrite = 1;
}
- lwb->lwb_zio = zio_rewrite(zilog->zl_root_zio, zilog->zl_spa,
- 0, &lwb->lwb_blk, lwb->lwb_buf, BP_GET_LSIZE(&lwb->lwb_blk),
- zil_lwb_write_done, lwb, ZIO_PRIORITY_LOG_WRITE,
- ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE |
+
+ if (!lwb->lwb_slog || zilog->zl_cur_used <= zil_slog_bulk)
+ prio = ZIO_PRIORITY_SYNC_WRITE;
+ else
+ prio = ZIO_PRIORITY_ASYNC_WRITE;
+
+ lwb->lwb_root_zio = zio_root(zilog->zl_spa,
+ zil_lwb_flush_vdevs_done, lwb, ZIO_FLAG_CANFAIL);
+ ASSERT3P(lwb->lwb_root_zio, !=, NULL);
+
+ lwb->lwb_write_zio = zio_rewrite(lwb->lwb_root_zio,
+ zilog->zl_spa, 0, &lwb->lwb_blk, lwb_abd,
+ BP_GET_LSIZE(&lwb->lwb_blk), zil_lwb_write_done, lwb,
+ prio, ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE |
ZIO_FLAG_FASTWRITE, &zb);
+ ASSERT3P(lwb->lwb_write_zio, !=, NULL);
+
+ lwb->lwb_state = LWB_STATE_OPENED;
+
+ zil_lwb_set_zio_dependency(zilog, lwb);
+ zilog->zl_last_lwb_opened = lwb;
}
mutex_exit(&zilog->zl_lock);
+
+ ASSERT3P(lwb->lwb_root_zio, !=, NULL);
+ ASSERT3P(lwb->lwb_write_zio, !=, NULL);
+ ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
}
/*
* Define a limited set of intent log block sizes.
+ *
* These must be a multiple of 4KB. Note only the amount used (again
* aligned to 4KB) actually gets written. However, we can't always just
- * allocate SPA_MAXBLOCKSIZE as the slog space could be exhausted.
+ * allocate SPA_OLD_MAXBLOCKSIZE as the slog space could be exhausted.
*/
uint64_t zil_block_buckets[] = {
4096, /* non TX_WRITE */
UINT64_MAX
};
-/*
- * Use the slog as long as the current commit size is less than the
- * limit or the total list size is less than 2X the limit. Limit
- * checking is disabled by setting zil_slog_limit to UINT64_MAX.
- */
-unsigned long zil_slog_limit = 1024 * 1024;
-#define USE_SLOG(zilog) (((zilog)->zl_cur_used < zil_slog_limit) || \
- ((zilog)->zl_itx_list_sz < (zil_slog_limit << 1)))
-
/*
* Start a log block write and advance to the next log block.
* Calls are serialized.
*/
static lwb_t *
-zil_lwb_write_start(zilog_t *zilog, lwb_t *lwb)
+zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb)
{
lwb_t *nlwb = NULL;
zil_chain_t *zilc;
uint64_t txg;
uint64_t zil_blksz, wsz;
int i, error;
- boolean_t use_slog;
+ boolean_t slog;
+
+ ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
+ ASSERT3P(lwb->lwb_root_zio, !=, NULL);
+ ASSERT3P(lwb->lwb_write_zio, !=, NULL);
+ ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
zilc = (zil_chain_t *)lwb->lwb_buf;
* We dirty the dataset to ensure that zil_sync() will be called
* to clean up in the event of allocation failure or I/O failure.
*/
+
tx = dmu_tx_create(zilog->zl_os);
- VERIFY(dmu_tx_assign(tx, TXG_WAIT) == 0);
- dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
+
+ /*
+ * Since we are not going to create any new dirty data, and we
+ * can even help with clearing the existing dirty data, we
+ * should not be subject to the dirty data based delays. We
+ * use TXG_NOTHROTTLE to bypass the delay mechanism.
+ */
+ VERIFY0(dmu_tx_assign(tx, TXG_WAIT | TXG_NOTHROTTLE));
+
+ dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
txg = dmu_tx_get_txg(tx);
lwb->lwb_tx = tx;
* close.
* - next find the maximum from the new suggested size and an array of
* previous sizes. This lessens a picket fence effect of wrongly
- * guesssing the size if we have a stream of say 2k, 64k, 2k, 64k
+ * guessing the size if we have a stream of say 2k, 64k, 2k, 64k
* requests.
*
* Note we only write what is used, but we can't just allocate
continue;
zil_blksz = zil_block_buckets[i];
if (zil_blksz == UINT64_MAX)
- zil_blksz = SPA_MAXBLOCKSIZE;
+ zil_blksz = SPA_OLD_MAXBLOCKSIZE;
zilog->zl_prev_blks[zilog->zl_prev_rotor] = zil_blksz;
for (i = 0; i < ZIL_PREV_BLKS; i++)
zil_blksz = MAX(zil_blksz, zilog->zl_prev_blks[i]);
zilog->zl_prev_rotor = (zilog->zl_prev_rotor + 1) & (ZIL_PREV_BLKS - 1);
BP_ZERO(bp);
- use_slog = USE_SLOG(zilog);
- error = zio_alloc_zil(spa, txg, bp, zil_blksz, USE_SLOG(zilog));
- if (use_slog)
- {
+ error = zio_alloc_zil(spa, zilog->zl_os, txg, bp, zil_blksz, &slog);
+ if (slog) {
ZIL_STAT_BUMP(zil_itx_metaslab_slog_count);
ZIL_STAT_INCR(zil_itx_metaslab_slog_bytes, lwb->lwb_nused);
- }
- else
- {
+ } else {
ZIL_STAT_BUMP(zil_itx_metaslab_normal_count);
ZIL_STAT_INCR(zil_itx_metaslab_normal_bytes, lwb->lwb_nused);
}
- if (!error) {
+ if (error == 0) {
ASSERT3U(bp->blk_birth, ==, txg);
bp->blk_cksum = lwb->lwb_blk.blk_cksum;
bp->blk_cksum.zc_word[ZIL_ZC_SEQ]++;
/*
- * Allocate a new log write buffer (lwb).
+ * Allocate a new log write block (lwb).
*/
- nlwb = zil_alloc_lwb(zilog, bp, txg, TRUE);
-
- /* Record the block for later vdev flushing */
- zil_add_block(zilog, &lwb->lwb_blk);
+ nlwb = zil_alloc_lwb(zilog, bp, slog, txg, TRUE);
}
if (BP_GET_CHECKSUM(&lwb->lwb_blk) == ZIO_CHECKSUM_ZILOG2) {
/* For Slim ZIL only write what is used. */
wsz = P2ROUNDUP_TYPED(lwb->lwb_nused, ZIL_MIN_BLKSZ, uint64_t);
ASSERT3U(wsz, <=, lwb->lwb_sz);
- zio_shrink(lwb->lwb_zio, wsz);
+ zio_shrink(lwb->lwb_write_zio, wsz);
} else {
wsz = lwb->lwb_sz;
*/
bzero(lwb->lwb_buf + lwb->lwb_nused, wsz - lwb->lwb_nused);
- zio_nowait(lwb->lwb_zio); /* Kick off the write for the old log block */
+ spa_config_enter(zilog->zl_spa, SCL_STATE, lwb, RW_READER);
+
+ zil_lwb_add_block(lwb, &lwb->lwb_blk);
+ lwb->lwb_issued_timestamp = gethrtime();
+ lwb->lwb_state = LWB_STATE_ISSUED;
+
+ zio_nowait(lwb->lwb_root_zio);
+ zio_nowait(lwb->lwb_write_zio);
/*
* If there was an allocation failure then nlwb will be null which
static lwb_t *
zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb)
{
- lr_t *lrc = &itx->itx_lr; /* common log record */
- lr_write_t *lrw = (lr_write_t *)lrc;
+ lr_t *lrcb, *lrc;
+ lr_write_t *lrwb, *lrw;
char *lr_buf;
- uint64_t txg = lrc->lrc_txg;
- uint64_t reclen = lrc->lrc_reclen;
- uint64_t dlen = 0;
+ uint64_t dlen, dnow, lwb_sp, reclen, txg;
- if (lwb == NULL)
- return (NULL);
+ ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
+ ASSERT3P(lwb, !=, NULL);
+ ASSERT3P(lwb->lwb_buf, !=, NULL);
- ASSERT(lwb->lwb_buf != NULL);
- ASSERT(zilog_is_dirty(zilog) ||
- spa_freeze_txg(zilog->zl_spa) != UINT64_MAX);
+ zil_lwb_write_open(zilog, lwb);
- if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY)
+ lrc = &itx->itx_lr;
+ lrw = (lr_write_t *)lrc;
+
+ /*
+ * A commit itx doesn't represent any on-disk state; instead
+ * it's simply used as a place holder on the commit list, and
+ * provides a mechanism for attaching a "commit waiter" onto the
+ * correct lwb (such that the waiter can be signalled upon
+ * completion of that lwb). Thus, we don't process this itx's
+ * log record if it's a commit itx (these itx's don't have log
+ * records), and instead link the itx's waiter onto the lwb's
+ * list of waiters.
+ *
+ * For more details, see the comment above zil_commit().
+ */
+ if (lrc->lrc_txtype == TX_COMMIT) {
+ mutex_enter(&zilog->zl_lock);
+ zil_commit_waiter_link_lwb(itx->itx_private, lwb);
+ itx->itx_private = NULL;
+ mutex_exit(&zilog->zl_lock);
+ return (lwb);
+ }
+
+ if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY) {
dlen = P2ROUNDUP_TYPED(
lrw->lr_length, sizeof (uint64_t), uint64_t);
-
+ } else {
+ dlen = 0;
+ }
+ reclen = lrc->lrc_reclen;
zilog->zl_cur_used += (reclen + dlen);
+ txg = lrc->lrc_txg;
- zil_lwb_write_init(zilog, lwb);
+ ASSERT3U(zilog->zl_cur_used, <, UINT64_MAX - (reclen + dlen));
+cont:
/*
* If this record won't fit in the current log block, start a new one.
+ * For WR_NEED_COPY optimize layout for minimal number of chunks.
*/
- if (lwb->lwb_nused + reclen + dlen > lwb->lwb_sz) {
- lwb = zil_lwb_write_start(zilog, lwb);
+ lwb_sp = lwb->lwb_sz - lwb->lwb_nused;
+ if (reclen > lwb_sp || (reclen + dlen > lwb_sp &&
+ lwb_sp < ZIL_MAX_WASTE_SPACE && (dlen % ZIL_MAX_LOG_DATA == 0 ||
+ lwb_sp < reclen + dlen % ZIL_MAX_LOG_DATA))) {
+ lwb = zil_lwb_write_issue(zilog, lwb);
if (lwb == NULL)
return (NULL);
- zil_lwb_write_init(zilog, lwb);
+ zil_lwb_write_open(zilog, lwb);
ASSERT(LWB_EMPTY(lwb));
- if (lwb->lwb_nused + reclen + dlen > lwb->lwb_sz) {
- txg_wait_synced(zilog->zl_dmu_pool, txg);
- return (lwb);
- }
+ lwb_sp = lwb->lwb_sz - lwb->lwb_nused;
+ ASSERT3U(reclen + MIN(dlen, sizeof (uint64_t)), <=, lwb_sp);
}
+ dnow = MIN(dlen, lwb_sp - reclen);
lr_buf = lwb->lwb_buf + lwb->lwb_nused;
bcopy(lrc, lr_buf, reclen);
- lrc = (lr_t *)lr_buf;
- lrw = (lr_write_t *)lrc;
+ lrcb = (lr_t *)lr_buf; /* Like lrc, but inside lwb. */
+ lrwb = (lr_write_t *)lrcb; /* Like lrw, but inside lwb. */
ZIL_STAT_BUMP(zil_itx_count);
char *dbuf;
int error;
- if (dlen) {
- ASSERT(itx->itx_wr_state == WR_NEED_COPY);
+ if (itx->itx_wr_state == WR_NEED_COPY) {
dbuf = lr_buf + reclen;
- lrw->lr_common.lrc_reclen += dlen;
+ lrcb->lrc_reclen += dnow;
+ if (lrwb->lr_length > dnow)
+ lrwb->lr_length = dnow;
+ lrw->lr_offset += dnow;
+ lrw->lr_length -= dnow;
ZIL_STAT_BUMP(zil_itx_needcopy_count);
- ZIL_STAT_INCR(zil_itx_needcopy_bytes, lrw->lr_length);
+ ZIL_STAT_INCR(zil_itx_needcopy_bytes, dnow);
} else {
- ASSERT(itx->itx_wr_state == WR_INDIRECT);
+ ASSERT3S(itx->itx_wr_state, ==, WR_INDIRECT);
dbuf = NULL;
ZIL_STAT_BUMP(zil_itx_indirect_count);
- ZIL_STAT_INCR(zil_itx_indirect_bytes, lrw->lr_length);
+ ZIL_STAT_INCR(zil_itx_indirect_bytes,
+ lrw->lr_length);
}
- error = zilog->zl_get_data(
- itx->itx_private, lrw, dbuf, lwb->lwb_zio);
+
+ /*
+ * We pass in the "lwb_write_zio" rather than
+ * "lwb_root_zio" so that the "lwb_write_zio"
+ * becomes the parent of any zio's created by
+ * the "zl_get_data" callback. The vdevs are
+ * flushed after the "lwb_write_zio" completes,
+ * so we want to make sure that completion
+ * callback waits for these additional zio's,
+ * such that the vdevs used by those zio's will
+ * be included in the lwb's vdev tree, and those
+ * vdevs will be properly flushed. If we passed
+ * in "lwb_root_zio" here, then these additional
+ * vdevs may not be flushed; e.g. if these zio's
+ * completed after "lwb_write_zio" completed.
+ */
+ error = zilog->zl_get_data(itx->itx_private,
+ lrwb, dbuf, lwb, lwb->lwb_write_zio);
+
if (error == EIO) {
txg_wait_synced(zilog->zl_dmu_pool, txg);
return (lwb);
}
- if (error) {
+ if (error != 0) {
ASSERT(error == ENOENT || error == EEXIST ||
error == EALREADY);
return (lwb);
* equal to the itx sequence number because not all transactions
* are synchronous, and sometimes spa_sync() gets there first.
*/
- lrc->lrc_seq = ++zilog->zl_lr_seq; /* we are single threaded */
- lwb->lwb_nused += reclen + dlen;
- lwb->lwb_max_txg = MAX(lwb->lwb_max_txg, txg);
+ lrcb->lrc_seq = ++zilog->zl_lr_seq;
+ lwb->lwb_nused += reclen + dnow;
+
+ zil_lwb_add_txg(lwb, txg);
+
ASSERT3U(lwb->lwb_nused, <=, lwb->lwb_sz);
ASSERT0(P2PHASE(lwb->lwb_nused, sizeof (uint64_t)));
+ dlen -= dnow;
+ if (dlen > 0) {
+ zilog->zl_cur_used += reclen;
+ goto cont;
+ }
+
return (lwb);
}
itx_t *
zil_itx_create(uint64_t txtype, size_t lrsize)
{
+ size_t itxsize;
itx_t *itx;
lrsize = P2ROUNDUP_TYPED(lrsize, sizeof (uint64_t), size_t);
+ itxsize = offsetof(itx_t, itx_lr) + lrsize;
- itx = kmem_alloc(offsetof(itx_t, itx_lr) + lrsize,
- KM_PUSHPAGE | KM_NODEBUG);
+ itx = zio_data_buf_alloc(itxsize);
itx->itx_lr.lrc_txtype = txtype;
itx->itx_lr.lrc_reclen = lrsize;
- itx->itx_sod = lrsize; /* if write & WR_NEED_COPY will be increased */
itx->itx_lr.lrc_seq = 0; /* defensive */
itx->itx_sync = B_TRUE; /* default is synchronous */
+ itx->itx_callback = NULL;
+ itx->itx_callback_data = NULL;
+ itx->itx_size = itxsize;
return (itx);
}
void
zil_itx_destroy(itx_t *itx)
{
- kmem_free(itx, offsetof(itx_t, itx_lr) + itx->itx_lr.lrc_reclen);
+ IMPLY(itx->itx_lr.lrc_txtype == TX_COMMIT, itx->itx_callback == NULL);
+ IMPLY(itx->itx_callback != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT);
+
+ if (itx->itx_callback != NULL)
+ itx->itx_callback(itx->itx_callback_data);
+
+ zio_data_buf_free(itx, itx->itx_size);
}
/*
list = &itxs->i_sync_list;
while ((itx = list_head(list)) != NULL) {
+ /*
+ * In the general case, commit itxs will not be found
+ * here, as they'll be committed to an lwb via
+ * zil_lwb_commit(), and free'd in that function. Having
+ * said that, it is still possible for commit itxs to be
+ * found here, due to the following race:
+ *
+ * - a thread calls zil_commit() which assigns the
+ * commit itx to a per-txg i_sync_list
+ * - zil_itxg_clean() is called (e.g. via spa_sync())
+ * while the waiter is still on the i_sync_list
+ *
+ * There's nothing to prevent syncing the txg while the
+ * waiter is on the i_sync_list. This normally doesn't
+ * happen because spa_sync() is slower than zil_commit(),
+ * but if zil_commit() calls txg_wait_synced() (e.g.
+ * because zil_create() or zil_commit_writer_stall() is
+ * called) we will hit this case.
+ */
+ if (itx->itx_lr.lrc_txtype == TX_COMMIT)
+ zil_commit_waiter_skip(itx->itx_private);
+
list_remove(list, itx);
- kmem_free(itx, offsetof(itx_t, itx_lr) +
- itx->itx_lr.lrc_reclen);
+ zil_itx_destroy(itx);
}
cookie = NULL;
list = &ian->ia_list;
while ((itx = list_head(list)) != NULL) {
list_remove(list, itx);
- kmem_free(itx, offsetof(itx_t, itx_lr) +
- itx->itx_lr.lrc_reclen);
+ /* commit itxs should never be on the async lists. */
+ ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT);
+ zil_itx_destroy(itx);
}
list_destroy(list);
kmem_free(ian, sizeof (itx_async_node_t));
const uint64_t o1 = ((itx_async_node_t *)x1)->ia_foid;
const uint64_t o2 = ((itx_async_node_t *)x2)->ia_foid;
- if (o1 < o2)
- return (-1);
- if (o1 > o2)
- return (1);
-
- return (0);
+ return (AVL_CMP(o1, o2));
}
/*
}
while ((itx = list_head(&clean_list)) != NULL) {
list_remove(&clean_list, itx);
- kmem_free(itx, offsetof(itx_t, itx_lr) +
- itx->itx_lr.lrc_reclen);
+ /* commit itxs should never be on the async lists. */
+ ASSERT3U(itx->itx_lr.lrc_txtype, !=, TX_COMMIT);
+ zil_itx_destroy(itx);
}
list_destroy(&clean_list);
}
* this itxg. Save the itxs for release below.
* This should be rare.
*/
- atomic_add_64(&zilog->zl_itx_list_sz, -itxg->itxg_sod);
- itxg->itxg_sod = 0;
+ zfs_dbgmsg("zil_itx_assign: missed itx cleanup for "
+ "txg %llu", itxg->itxg_txg);
clean = itxg->itxg_itxs;
}
- ASSERT(itxg->itxg_sod == 0);
itxg->itxg_txg = txg;
- itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t), KM_PUSHPAGE);
+ itxs = itxg->itxg_itxs = kmem_zalloc(sizeof (itxs_t),
+ KM_SLEEP);
list_create(&itxs->i_sync_list, sizeof (itx_t),
offsetof(itx_t, itx_node));
}
if (itx->itx_sync) {
list_insert_tail(&itxs->i_sync_list, itx);
- atomic_add_64(&zilog->zl_itx_list_sz, itx->itx_sod);
- itxg->itxg_sod += itx->itx_sod;
} else {
avl_tree_t *t = &itxs->i_async_tree;
- uint64_t foid = ((lr_ooo_t *)&itx->itx_lr)->lr_foid;
+ uint64_t foid =
+ LR_FOID_GET_OBJ(((lr_ooo_t *)&itx->itx_lr)->lr_foid);
itx_async_node_t *ian;
avl_index_t where;
ian = avl_find(t, &foid, &where);
if (ian == NULL) {
- ian = kmem_alloc(sizeof (itx_async_node_t), KM_PUSHPAGE);
+ ian = kmem_alloc(sizeof (itx_async_node_t),
+ KM_SLEEP);
list_create(&ian->ia_list, sizeof (itx_t),
offsetof(itx_t, itx_node));
ian->ia_foid = foid;
}
itx->itx_lr.lrc_txg = dmu_tx_get_txg(tx);
- zilog_dirty(zilog, txg);
+
+ /*
+ * We don't want to dirty the ZIL using ZILTEST_TXG, because
+ * zil_clean() will never be called using ZILTEST_TXG. Thus, we
+ * need to be careful to always dirty the ZIL using the "real"
+ * TXG (not itxg_txg) even when the SPA is frozen.
+ */
+ zilog_dirty(zilog, dmu_tx_get_txg(tx));
mutex_exit(&itxg->itxg_lock);
/* Release the old itxs now we've dropped the lock */
itxg_t *itxg = &zilog->zl_itxg[synced_txg & TXG_MASK];
itxs_t *clean_me;
+ ASSERT3U(synced_txg, <, ZILTEST_TXG);
+
mutex_enter(&itxg->itxg_lock);
if (itxg->itxg_itxs == NULL || itxg->itxg_txg == ZILTEST_TXG) {
mutex_exit(&itxg->itxg_lock);
return;
}
ASSERT3U(itxg->itxg_txg, <=, synced_txg);
- ASSERT(itxg->itxg_txg != 0);
- ASSERT(zilog->zl_clean_taskq != NULL);
- atomic_add_64(&zilog->zl_itx_list_sz, -itxg->itxg_sod);
- itxg->itxg_sod = 0;
+ ASSERT3U(itxg->itxg_txg, !=, 0);
clean_me = itxg->itxg_itxs;
itxg->itxg_itxs = NULL;
itxg->itxg_txg = 0;
* free it in-line. This should be rare. Note, using TQ_SLEEP
* created a bad performance problem.
*/
- if (taskq_dispatch(zilog->zl_clean_taskq,
- (void (*)(void *))zil_itxg_clean, clean_me, TQ_NOSLEEP) == 0)
+ ASSERT3P(zilog->zl_dmu_pool, !=, NULL);
+ ASSERT3P(zilog->zl_dmu_pool->dp_zil_clean_taskq, !=, NULL);
+ taskqid_t id = taskq_dispatch(zilog->zl_dmu_pool->dp_zil_clean_taskq,
+ (void (*)(void *))zil_itxg_clean, clean_me, TQ_NOSLEEP);
+ if (id == TASKQID_INVALID)
zil_itxg_clean(clean_me);
}
/*
- * Get the list of itxs to commit into zl_itx_commit_list.
+ * This function will traverse the queue of itxs that need to be
+ * committed, and move them onto the ZIL's zl_itx_commit_list.
*/
static void
zil_get_commit_list(zilog_t *zilog)
{
uint64_t otxg, txg;
list_t *commit_list = &zilog->zl_itx_commit_list;
- uint64_t push_sod = 0;
+
+ ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
if (spa_freeze_txg(zilog->zl_spa) != UINT64_MAX) /* ziltest support */
otxg = ZILTEST_TXG;
else
otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
+ /*
+ * This is inherently racy, since there is nothing to prevent
+ * the last synced txg from changing. That's okay since we'll
+ * only commit things in the future.
+ */
for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
continue;
}
+ /*
+ * If we're adding itx records to the zl_itx_commit_list,
+ * then the zil better be dirty in this "txg". We can assert
+ * that here since we're holding the itxg_lock which will
+ * prevent spa_sync from cleaning it. Once we add the itxs
+ * to the zl_itx_commit_list we must commit it to disk even
+ * if it's unnecessary (i.e. the txg was synced).
+ */
+ ASSERT(zilog_is_dirty_in_txg(zilog, txg) ||
+ spa_freeze_txg(zilog->zl_spa) != UINT64_MAX);
list_move_tail(commit_list, &itxg->itxg_itxs->i_sync_list);
- push_sod += itxg->itxg_sod;
- itxg->itxg_sod = 0;
mutex_exit(&itxg->itxg_lock);
}
- atomic_add_64(&zilog->zl_itx_list_sz, -push_sod);
}
/*
else
otxg = spa_last_synced_txg(zilog->zl_spa) + 1;
+ /*
+ * This is inherently racy, since there is nothing to prevent
+ * the last synced txg from changing.
+ */
for (txg = otxg; txg < (otxg + TXG_CONCURRENT_STATES); txg++) {
itxg_t *itxg = &zilog->zl_itxg[txg & TXG_MASK];
}
}
+/*
+ * This function will prune commit itxs that are at the head of the
+ * commit list (it won't prune past the first non-commit itx), and
+ * either: a) attach them to the last lwb that's still pending
+ * completion, or b) skip them altogether.
+ *
+ * This is used as a performance optimization to prevent commit itxs
+ * from generating new lwbs when it's unnecessary to do so.
+ */
static void
-zil_commit_writer(zilog_t *zilog)
+zil_prune_commit_list(zilog_t *zilog)
{
- uint64_t txg;
itx_t *itx;
- lwb_t *lwb;
- spa_t *spa = zilog->zl_spa;
- int error = 0;
- ASSERT(zilog->zl_root_zio == NULL);
+ ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
- mutex_exit(&zilog->zl_lock);
+ while ((itx = list_head(&zilog->zl_itx_commit_list)) != NULL) {
+ lr_t *lrc = &itx->itx_lr;
+ if (lrc->lrc_txtype != TX_COMMIT)
+ break;
- zil_get_commit_list(zilog);
+ mutex_enter(&zilog->zl_lock);
+
+ lwb_t *last_lwb = zilog->zl_last_lwb_opened;
+ if (last_lwb == NULL ||
+ last_lwb->lwb_state == LWB_STATE_FLUSH_DONE) {
+ /*
+ * All of the itxs this waiter was waiting on
+ * must have already completed (or there were
+ * never any itx's for it to wait on), so it's
+ * safe to skip this waiter and mark it done.
+ */
+ zil_commit_waiter_skip(itx->itx_private);
+ } else {
+ zil_commit_waiter_link_lwb(itx->itx_private, last_lwb);
+ itx->itx_private = NULL;
+ }
+
+ mutex_exit(&zilog->zl_lock);
+
+ list_remove(&zilog->zl_itx_commit_list, itx);
+ zil_itx_destroy(itx);
+ }
+
+ IMPLY(itx != NULL, itx->itx_lr.lrc_txtype != TX_COMMIT);
+}
+
+static void
+zil_commit_writer_stall(zilog_t *zilog)
+{
+ /*
+ * When zio_alloc_zil() fails to allocate the next lwb block on
+ * disk, we must call txg_wait_synced() to ensure all of the
+ * lwbs in the zilog's zl_lwb_list are synced and then freed (in
+ * zil_sync()), such that any subsequent ZIL writer (i.e. a call
+ * to zil_process_commit_list()) will have to call zil_create(),
+ * and start a new ZIL chain.
+ *
+ * Since zil_alloc_zil() failed, the lwb that was previously
+ * issued does not have a pointer to the "next" lwb on disk.
+ * Thus, if another ZIL writer thread was to allocate the "next"
+ * on-disk lwb, that block could be leaked in the event of a
+ * crash (because the previous lwb on-disk would not point to
+ * it).
+ *
+ * We must hold the zilog's zl_issuer_lock while we do this, to
+ * ensure no new threads enter zil_process_commit_list() until
+ * all lwb's in the zl_lwb_list have been synced and freed
+ * (which is achieved via the txg_wait_synced() call).
+ */
+ ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
+ txg_wait_synced(zilog->zl_dmu_pool, 0);
+ ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL);
+}
+
+/*
+ * This function will traverse the commit list, creating new lwbs as
+ * needed, and committing the itxs from the commit list to these newly
+ * created lwbs. Additionally, as a new lwb is created, the previous
+ * lwb will be issued to the zio layer to be written to disk.
+ */
+static void
+zil_process_commit_list(zilog_t *zilog)
+{
+ spa_t *spa = zilog->zl_spa;
+ list_t nolwb_itxs;
+ list_t nolwb_waiters;
+ lwb_t *lwb;
+ itx_t *itx;
+
+ ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock));
/*
* Return if there's nothing to commit before we dirty the fs by
* calling zil_create().
*/
- if (list_head(&zilog->zl_itx_commit_list) == NULL) {
- mutex_enter(&zilog->zl_lock);
+ if (list_head(&zilog->zl_itx_commit_list) == NULL)
return;
- }
- if (zilog->zl_suspend) {
- lwb = NULL;
+ list_create(&nolwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node));
+ list_create(&nolwb_waiters, sizeof (zil_commit_waiter_t),
+ offsetof(zil_commit_waiter_t, zcw_node));
+
+ lwb = list_tail(&zilog->zl_lwb_list);
+ if (lwb == NULL) {
+ lwb = zil_create(zilog);
} else {
- lwb = list_tail(&zilog->zl_lwb_list);
- if (lwb == NULL)
- lwb = zil_create(zilog);
+ ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED);
+ ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
+ ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
}
- DTRACE_PROBE1(zil__cw1, zilog_t *, zilog);
- while ((itx = list_head(&zilog->zl_itx_commit_list))) {
- txg = itx->itx_lr.lrc_txg;
- ASSERT(txg);
+ while ((itx = list_head(&zilog->zl_itx_commit_list)) != NULL) {
+ lr_t *lrc = &itx->itx_lr;
+ uint64_t txg = lrc->lrc_txg;
+
+ ASSERT3U(txg, !=, 0);
+
+ if (lrc->lrc_txtype == TX_COMMIT) {
+ DTRACE_PROBE2(zil__process__commit__itx,
+ zilog_t *, zilog, itx_t *, itx);
+ } else {
+ DTRACE_PROBE2(zil__process__normal__itx,
+ zilog_t *, zilog, itx_t *, itx);
+ }
- if (txg > spa_last_synced_txg(spa) || txg > spa_freeze_txg(spa))
- lwb = zil_lwb_commit(zilog, itx, lwb);
list_remove(&zilog->zl_itx_commit_list, itx);
- kmem_free(itx, offsetof(itx_t, itx_lr)
- + itx->itx_lr.lrc_reclen);
+
+ boolean_t synced = txg <= spa_last_synced_txg(spa);
+ boolean_t frozen = txg > spa_freeze_txg(spa);
+
+ /*
+ * If the txg of this itx has already been synced out, then
+ * we don't need to commit this itx to an lwb. This is
+ * because the data of this itx will have already been
+ * written to the main pool. This is inherently racy, and
+ * it's still ok to commit an itx whose txg has already
+ * been synced; this will result in a write that's
+ * unnecessary, but will do no harm.
+ *
+ * With that said, we always want to commit TX_COMMIT itxs
+ * to an lwb, regardless of whether or not that itx's txg
+ * has been synced out. We do this to ensure any OPENED lwb
+ * will always have at least one zil_commit_waiter_t linked
+ * to the lwb.
+ *
+ * As a counter-example, if we skipped TX_COMMIT itx's
+ * whose txg had already been synced, the following
+ * situation could occur if we happened to be racing with
+ * spa_sync:
+ *
+ * 1. We commit a non-TX_COMMIT itx to an lwb, where the
+ * itx's txg is 10 and the last synced txg is 9.
+ * 2. spa_sync finishes syncing out txg 10.
+ * 3. We move to the next itx in the list, it's a TX_COMMIT
+ * whose txg is 10, so we skip it rather than committing
+ * it to the lwb used in (1).
+ *
+ * If the itx that is skipped in (3) is the last TX_COMMIT
+ * itx in the commit list, than it's possible for the lwb
+ * used in (1) to remain in the OPENED state indefinitely.
+ *
+ * To prevent the above scenario from occurring, ensuring
+ * that once an lwb is OPENED it will transition to ISSUED
+ * and eventually DONE, we always commit TX_COMMIT itx's to
+ * an lwb here, even if that itx's txg has already been
+ * synced.
+ *
+ * Finally, if the pool is frozen, we _always_ commit the
+ * itx. The point of freezing the pool is to prevent data
+ * from being written to the main pool via spa_sync, and
+ * instead rely solely on the ZIL to persistently store the
+ * data; i.e. when the pool is frozen, the last synced txg
+ * value can't be trusted.
+ */
+ if (frozen || !synced || lrc->lrc_txtype == TX_COMMIT) {
+ if (lwb != NULL) {
+ lwb = zil_lwb_commit(zilog, itx, lwb);
+
+ if (lwb == NULL)
+ list_insert_tail(&nolwb_itxs, itx);
+ else
+ list_insert_tail(&lwb->lwb_itxs, itx);
+ } else {
+ if (lrc->lrc_txtype == TX_COMMIT) {
+ zil_commit_waiter_link_nolwb(
+ itx->itx_private, &nolwb_waiters);
+ }
+
+ list_insert_tail(&nolwb_itxs, itx);
+ }
+ } else {
+ ASSERT3S(lrc->lrc_txtype, !=, TX_COMMIT);
+ zil_itx_destroy(itx);
+ }
}
- DTRACE_PROBE1(zil__cw2, zilog_t *, zilog);
- /* write the last block out */
- if (lwb != NULL && lwb->lwb_zio != NULL)
- lwb = zil_lwb_write_start(zilog, lwb);
+ if (lwb == NULL) {
+ /*
+ * This indicates zio_alloc_zil() failed to allocate the
+ * "next" lwb on-disk. When this happens, we must stall
+ * the ZIL write pipeline; see the comment within
+ * zil_commit_writer_stall() for more details.
+ */
+ zil_commit_writer_stall(zilog);
- zilog->zl_cur_used = 0;
+ /*
+ * Additionally, we have to signal and mark the "nolwb"
+ * waiters as "done" here, since without an lwb, we
+ * can't do this via zil_lwb_flush_vdevs_done() like
+ * normal.
+ */
+ zil_commit_waiter_t *zcw;
+ while ((zcw = list_head(&nolwb_waiters)) != NULL) {
+ zil_commit_waiter_skip(zcw);
+ list_remove(&nolwb_waiters, zcw);
+ }
+
+ /*
+ * And finally, we have to destroy the itx's that
+ * couldn't be committed to an lwb; this will also call
+ * the itx's callback if one exists for the itx.
+ */
+ while ((itx = list_head(&nolwb_itxs)) != NULL) {
+ list_remove(&nolwb_itxs, itx);
+ zil_itx_destroy(itx);
+ }
+ } else {
+ ASSERT(list_is_empty(&nolwb_waiters));
+ ASSERT3P(lwb, !=, NULL);
+ ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED);
+ ASSERT3S(lwb->lwb_state, !=, LWB_STATE_WRITE_DONE);
+ ASSERT3S(lwb->lwb_state, !=, LWB_STATE_FLUSH_DONE);
+
+ /*
+ * At this point, the ZIL block pointed at by the "lwb"
+ * variable is in one of the following states: "closed"
+ * or "open".
+ *
+ * If it's "closed", then no itxs have been committed to
+ * it, so there's no point in issuing its zio (i.e. it's
+ * "empty").
+ *
+ * If it's "open", then it contains one or more itxs that
+ * eventually need to be committed to stable storage. In
+ * this case we intentionally do not issue the lwb's zio
+ * to disk yet, and instead rely on one of the following
+ * two mechanisms for issuing the zio:
+ *
+ * 1. Ideally, there will be more ZIL activity occurring
+ * on the system, such that this function will be
+ * immediately called again (not necessarily by the same
+ * thread) and this lwb's zio will be issued via
+ * zil_lwb_commit(). This way, the lwb is guaranteed to
+ * be "full" when it is issued to disk, and we'll make
+ * use of the lwb's size the best we can.
+ *
+ * 2. If there isn't sufficient ZIL activity occurring on
+ * the system, such that this lwb's zio isn't issued via
+ * zil_lwb_commit(), zil_commit_waiter() will issue the
+ * lwb's zio. If this occurs, the lwb is not guaranteed
+ * to be "full" by the time its zio is issued, and means
+ * the size of the lwb was "too large" given the amount
+ * of ZIL activity occurring on the system at that time.
+ *
+ * We do this for a couple of reasons:
+ *
+ * 1. To try and reduce the number of IOPs needed to
+ * write the same number of itxs. If an lwb has space
+ * available in its buffer for more itxs, and more itxs
+ * will be committed relatively soon (relative to the
+ * latency of performing a write), then it's beneficial
+ * to wait for these "next" itxs. This way, more itxs
+ * can be committed to stable storage with fewer writes.
+ *
+ * 2. To try and use the largest lwb block size that the
+ * incoming rate of itxs can support. Again, this is to
+ * try and pack as many itxs into as few lwbs as
+ * possible, without significantly impacting the latency
+ * of each individual itx.
+ */
+ }
+}
+
+/*
+ * This function is responsible for ensuring the passed in commit waiter
+ * (and associated commit itx) is committed to an lwb. If the waiter is
+ * not already committed to an lwb, all itxs in the zilog's queue of
+ * itxs will be processed. The assumption is the passed in waiter's
+ * commit itx will found in the queue just like the other non-commit
+ * itxs, such that when the entire queue is processed, the waiter will
+ * have been committed to an lwb.
+ *
+ * The lwb associated with the passed in waiter is not guaranteed to
+ * have been issued by the time this function completes. If the lwb is
+ * not issued, we rely on future calls to zil_commit_writer() to issue
+ * the lwb, or the timeout mechanism found in zil_commit_waiter().
+ */
+static void
+zil_commit_writer(zilog_t *zilog, zil_commit_waiter_t *zcw)
+{
+ ASSERT(!MUTEX_HELD(&zilog->zl_lock));
+ ASSERT(spa_writeable(zilog->zl_spa));
+
+ mutex_enter(&zilog->zl_issuer_lock);
+
+ if (zcw->zcw_lwb != NULL || zcw->zcw_done) {
+ /*
+ * It's possible that, while we were waiting to acquire
+ * the "zl_issuer_lock", another thread committed this
+ * waiter to an lwb. If that occurs, we bail out early,
+ * without processing any of the zilog's queue of itxs.
+ *
+ * On certain workloads and system configurations, the
+ * "zl_issuer_lock" can become highly contended. In an
+ * attempt to reduce this contention, we immediately drop
+ * the lock if the waiter has already been processed.
+ *
+ * We've measured this optimization to reduce CPU spent
+ * contending on this lock by up to 5%, using a system
+ * with 32 CPUs, low latency storage (~50 usec writes),
+ * and 1024 threads performing sync writes.
+ */
+ goto out;
+ }
+
+ ZIL_STAT_BUMP(zil_commit_writer_count);
+
+ zil_get_commit_list(zilog);
+ zil_prune_commit_list(zilog);
+ zil_process_commit_list(zilog);
+
+out:
+ mutex_exit(&zilog->zl_issuer_lock);
+}
+
+static void
+zil_commit_waiter_timeout(zilog_t *zilog, zil_commit_waiter_t *zcw)
+{
+ ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock));
+ ASSERT(MUTEX_HELD(&zcw->zcw_lock));
+ ASSERT3B(zcw->zcw_done, ==, B_FALSE);
+
+ lwb_t *lwb = zcw->zcw_lwb;
+ ASSERT3P(lwb, !=, NULL);
+ ASSERT3S(lwb->lwb_state, !=, LWB_STATE_CLOSED);
+
+ /*
+ * If the lwb has already been issued by another thread, we can
+ * immediately return since there's no work to be done (the
+ * point of this function is to issue the lwb). Additionally, we
+ * do this prior to acquiring the zl_issuer_lock, to avoid
+ * acquiring it when it's not necessary to do so.
+ */
+ if (lwb->lwb_state == LWB_STATE_ISSUED ||
+ lwb->lwb_state == LWB_STATE_WRITE_DONE ||
+ lwb->lwb_state == LWB_STATE_FLUSH_DONE)
+ return;
/*
- * Wait if necessary for the log blocks to be on stable storage.
+ * In order to call zil_lwb_write_issue() we must hold the
+ * zilog's "zl_issuer_lock". We can't simply acquire that lock,
+ * since we're already holding the commit waiter's "zcw_lock",
+ * and those two locks are acquired in the opposite order
+ * elsewhere.
*/
- if (zilog->zl_root_zio) {
- error = zio_wait(zilog->zl_root_zio);
- zilog->zl_root_zio = NULL;
- zil_flush_vdevs(zilog);
+ mutex_exit(&zcw->zcw_lock);
+ mutex_enter(&zilog->zl_issuer_lock);
+ mutex_enter(&zcw->zcw_lock);
+
+ /*
+ * Since we just dropped and re-acquired the commit waiter's
+ * lock, we have to re-check to see if the waiter was marked
+ * "done" during that process. If the waiter was marked "done",
+ * the "lwb" pointer is no longer valid (it can be free'd after
+ * the waiter is marked "done"), so without this check we could
+ * wind up with a use-after-free error below.
+ */
+ if (zcw->zcw_done)
+ goto out;
+
+ ASSERT3P(lwb, ==, zcw->zcw_lwb);
+
+ /*
+ * We've already checked this above, but since we hadn't acquired
+ * the zilog's zl_issuer_lock, we have to perform this check a
+ * second time while holding the lock.
+ *
+ * We don't need to hold the zl_lock since the lwb cannot transition
+ * from OPENED to ISSUED while we hold the zl_issuer_lock. The lwb
+ * _can_ transition from ISSUED to DONE, but it's OK to race with
+ * that transition since we treat the lwb the same, whether it's in
+ * the ISSUED or DONE states.
+ *
+ * The important thing, is we treat the lwb differently depending on
+ * if it's ISSUED or OPENED, and block any other threads that might
+ * attempt to issue this lwb. For that reason we hold the
+ * zl_issuer_lock when checking the lwb_state; we must not call
+ * zil_lwb_write_issue() if the lwb had already been issued.
+ *
+ * See the comment above the lwb_state_t structure definition for
+ * more details on the lwb states, and locking requirements.
+ */
+ if (lwb->lwb_state == LWB_STATE_ISSUED ||
+ lwb->lwb_state == LWB_STATE_WRITE_DONE ||
+ lwb->lwb_state == LWB_STATE_FLUSH_DONE)
+ goto out;
+
+ ASSERT3S(lwb->lwb_state, ==, LWB_STATE_OPENED);
+
+ /*
+ * As described in the comments above zil_commit_waiter() and
+ * zil_process_commit_list(), we need to issue this lwb's zio
+ * since we've reached the commit waiter's timeout and it still
+ * hasn't been issued.
+ */
+ lwb_t *nlwb = zil_lwb_write_issue(zilog, lwb);
+
+ IMPLY(nlwb != NULL, lwb->lwb_state != LWB_STATE_OPENED);
+
+ /*
+ * Since the lwb's zio hadn't been issued by the time this thread
+ * reached its timeout, we reset the zilog's "zl_cur_used" field
+ * to influence the zil block size selection algorithm.
+ *
+ * By having to issue the lwb's zio here, it means the size of the
+ * lwb was too large, given the incoming throughput of itxs. By
+ * setting "zl_cur_used" to zero, we communicate this fact to the
+ * block size selection algorithm, so it can take this information
+ * into account, and potentially select a smaller size for the
+ * next lwb block that is allocated.
+ */
+ zilog->zl_cur_used = 0;
+
+ if (nlwb == NULL) {
+ /*
+ * When zil_lwb_write_issue() returns NULL, this
+ * indicates zio_alloc_zil() failed to allocate the
+ * "next" lwb on-disk. When this occurs, the ZIL write
+ * pipeline must be stalled; see the comment within the
+ * zil_commit_writer_stall() function for more details.
+ *
+ * We must drop the commit waiter's lock prior to
+ * calling zil_commit_writer_stall() or else we can wind
+ * up with the following deadlock:
+ *
+ * - This thread is waiting for the txg to sync while
+ * holding the waiter's lock; txg_wait_synced() is
+ * used within txg_commit_writer_stall().
+ *
+ * - The txg can't sync because it is waiting for this
+ * lwb's zio callback to call dmu_tx_commit().
+ *
+ * - The lwb's zio callback can't call dmu_tx_commit()
+ * because it's blocked trying to acquire the waiter's
+ * lock, which occurs prior to calling dmu_tx_commit()
+ */
+ mutex_exit(&zcw->zcw_lock);
+ zil_commit_writer_stall(zilog);
+ mutex_enter(&zcw->zcw_lock);
}
- if (error || lwb == NULL)
- txg_wait_synced(zilog->zl_dmu_pool, 0);
+out:
+ mutex_exit(&zilog->zl_issuer_lock);
+ ASSERT(MUTEX_HELD(&zcw->zcw_lock));
+}
- mutex_enter(&zilog->zl_lock);
+/*
+ * This function is responsible for performing the following two tasks:
+ *
+ * 1. its primary responsibility is to block until the given "commit
+ * waiter" is considered "done".
+ *
+ * 2. its secondary responsibility is to issue the zio for the lwb that
+ * the given "commit waiter" is waiting on, if this function has
+ * waited "long enough" and the lwb is still in the "open" state.
+ *
+ * Given a sufficient amount of itxs being generated and written using
+ * the ZIL, the lwb's zio will be issued via the zil_lwb_commit()
+ * function. If this does not occur, this secondary responsibility will
+ * ensure the lwb is issued even if there is not other synchronous
+ * activity on the system.
+ *
+ * For more details, see zil_process_commit_list(); more specifically,
+ * the comment at the bottom of that function.
+ */
+static void
+zil_commit_waiter(zilog_t *zilog, zil_commit_waiter_t *zcw)
+{
+ ASSERT(!MUTEX_HELD(&zilog->zl_lock));
+ ASSERT(!MUTEX_HELD(&zilog->zl_issuer_lock));
+ ASSERT(spa_writeable(zilog->zl_spa));
+
+ mutex_enter(&zcw->zcw_lock);
/*
- * Remember the highest committed log sequence number for ztest.
- * We only update this value when all the log writes succeeded,
- * because ztest wants to ASSERT that it got the whole log chain.
+ * The timeout is scaled based on the lwb latency to avoid
+ * significantly impacting the latency of each individual itx.
+ * For more details, see the comment at the bottom of the
+ * zil_process_commit_list() function.
*/
- if (error == 0 && lwb != NULL)
- zilog->zl_commit_lr_seq = zilog->zl_lr_seq;
+ int pct = MAX(zfs_commit_timeout_pct, 1);
+ hrtime_t sleep = (zilog->zl_last_lwb_latency * pct) / 100;
+ hrtime_t wakeup = gethrtime() + sleep;
+ boolean_t timedout = B_FALSE;
+
+ while (!zcw->zcw_done) {
+ ASSERT(MUTEX_HELD(&zcw->zcw_lock));
+
+ lwb_t *lwb = zcw->zcw_lwb;
+
+ /*
+ * Usually, the waiter will have a non-NULL lwb field here,
+ * but it's possible for it to be NULL as a result of
+ * zil_commit() racing with spa_sync().
+ *
+ * When zil_clean() is called, it's possible for the itxg
+ * list (which may be cleaned via a taskq) to contain
+ * commit itxs. When this occurs, the commit waiters linked
+ * off of these commit itxs will not be committed to an
+ * lwb. Additionally, these commit waiters will not be
+ * marked done until zil_commit_waiter_skip() is called via
+ * zil_itxg_clean().
+ *
+ * Thus, it's possible for this commit waiter (i.e. the
+ * "zcw" variable) to be found in this "in between" state;
+ * where it's "zcw_lwb" field is NULL, and it hasn't yet
+ * been skipped, so it's "zcw_done" field is still B_FALSE.
+ */
+ IMPLY(lwb != NULL, lwb->lwb_state != LWB_STATE_CLOSED);
+
+ if (lwb != NULL && lwb->lwb_state == LWB_STATE_OPENED) {
+ ASSERT3B(timedout, ==, B_FALSE);
+
+ /*
+ * If the lwb hasn't been issued yet, then we
+ * need to wait with a timeout, in case this
+ * function needs to issue the lwb after the
+ * timeout is reached; responsibility (2) from
+ * the comment above this function.
+ */
+ clock_t timeleft = cv_timedwait_hires(&zcw->zcw_cv,
+ &zcw->zcw_lock, wakeup, USEC2NSEC(1),
+ CALLOUT_FLAG_ABSOLUTE);
+
+ if (timeleft >= 0 || zcw->zcw_done)
+ continue;
+
+ timedout = B_TRUE;
+ zil_commit_waiter_timeout(zilog, zcw);
+
+ if (!zcw->zcw_done) {
+ /*
+ * If the commit waiter has already been
+ * marked "done", it's possible for the
+ * waiter's lwb structure to have already
+ * been freed. Thus, we can only reliably
+ * make these assertions if the waiter
+ * isn't done.
+ */
+ ASSERT3P(lwb, ==, zcw->zcw_lwb);
+ ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED);
+ }
+ } else {
+ /*
+ * If the lwb isn't open, then it must have already
+ * been issued. In that case, there's no need to
+ * use a timeout when waiting for the lwb to
+ * complete.
+ *
+ * Additionally, if the lwb is NULL, the waiter
+ * will soon be signaled and marked done via
+ * zil_clean() and zil_itxg_clean(), so no timeout
+ * is required.
+ */
+
+ IMPLY(lwb != NULL,
+ lwb->lwb_state == LWB_STATE_ISSUED ||
+ lwb->lwb_state == LWB_STATE_WRITE_DONE ||
+ lwb->lwb_state == LWB_STATE_FLUSH_DONE);
+ cv_wait(&zcw->zcw_cv, &zcw->zcw_lock);
+ }
+ }
+
+ mutex_exit(&zcw->zcw_lock);
+}
+
+static zil_commit_waiter_t *
+zil_alloc_commit_waiter(void)
+{
+ zil_commit_waiter_t *zcw = kmem_cache_alloc(zil_zcw_cache, KM_SLEEP);
+
+ cv_init(&zcw->zcw_cv, NULL, CV_DEFAULT, NULL);
+ mutex_init(&zcw->zcw_lock, NULL, MUTEX_DEFAULT, NULL);
+ list_link_init(&zcw->zcw_node);
+ zcw->zcw_lwb = NULL;
+ zcw->zcw_done = B_FALSE;
+ zcw->zcw_zio_error = 0;
+
+ return (zcw);
+}
+
+static void
+zil_free_commit_waiter(zil_commit_waiter_t *zcw)
+{
+ ASSERT(!list_link_active(&zcw->zcw_node));
+ ASSERT3P(zcw->zcw_lwb, ==, NULL);
+ ASSERT3B(zcw->zcw_done, ==, B_TRUE);
+ mutex_destroy(&zcw->zcw_lock);
+ cv_destroy(&zcw->zcw_cv);
+ kmem_cache_free(zil_zcw_cache, zcw);
+}
+
+/*
+ * This function is used to create a TX_COMMIT itx and assign it. This
+ * way, it will be linked into the ZIL's list of synchronous itxs, and
+ * then later committed to an lwb (or skipped) when
+ * zil_process_commit_list() is called.
+ */
+static void
+zil_commit_itx_assign(zilog_t *zilog, zil_commit_waiter_t *zcw)
+{
+ dmu_tx_t *tx = dmu_tx_create(zilog->zl_os);
+ VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
+
+ itx_t *itx = zil_itx_create(TX_COMMIT, sizeof (lr_t));
+ itx->itx_sync = B_TRUE;
+ itx->itx_private = zcw;
+
+ zil_itx_assign(zilog, itx, tx);
+
+ dmu_tx_commit(tx);
}
/*
- * Commit zfs transactions to stable storage.
- * If foid is 0 push out all transactions, otherwise push only those
- * for that object or might reference that object.
+ * Commit ZFS Intent Log transactions (itxs) to stable storage.
+ *
+ * When writing ZIL transactions to the on-disk representation of the
+ * ZIL, the itxs are committed to a Log Write Block (lwb). Multiple
+ * itxs can be committed to a single lwb. Once a lwb is written and
+ * committed to stable storage (i.e. the lwb is written, and vdevs have
+ * been flushed), each itx that was committed to that lwb is also
+ * considered to be committed to stable storage.
+ *
+ * When an itx is committed to an lwb, the log record (lr_t) contained
+ * by the itx is copied into the lwb's zio buffer, and once this buffer
+ * is written to disk, it becomes an on-disk ZIL block.
+ *
+ * As itxs are generated, they're inserted into the ZIL's queue of
+ * uncommitted itxs. The semantics of zil_commit() are such that it will
+ * block until all itxs that were in the queue when it was called, are
+ * committed to stable storage.
+ *
+ * If "foid" is zero, this means all "synchronous" and "asynchronous"
+ * itxs, for all objects in the dataset, will be committed to stable
+ * storage prior to zil_commit() returning. If "foid" is non-zero, all
+ * "synchronous" itxs for all objects, but only "asynchronous" itxs
+ * that correspond to the foid passed in, will be committed to stable
+ * storage prior to zil_commit() returning.
+ *
+ * Generally speaking, when zil_commit() is called, the consumer doesn't
+ * actually care about _all_ of the uncommitted itxs. Instead, they're
+ * simply trying to waiting for a specific itx to be committed to disk,
+ * but the interface(s) for interacting with the ZIL don't allow such
+ * fine-grained communication. A better interface would allow a consumer
+ * to create and assign an itx, and then pass a reference to this itx to
+ * zil_commit(); such that zil_commit() would return as soon as that
+ * specific itx was committed to disk (instead of waiting for _all_
+ * itxs to be committed).
+ *
+ * When a thread calls zil_commit() a special "commit itx" will be
+ * generated, along with a corresponding "waiter" for this commit itx.
+ * zil_commit() will wait on this waiter's CV, such that when the waiter
+ * is marked done, and signaled, zil_commit() will return.
+ *
+ * This commit itx is inserted into the queue of uncommitted itxs. This
+ * provides an easy mechanism for determining which itxs were in the
+ * queue prior to zil_commit() having been called, and which itxs were
+ * added after zil_commit() was called.
+ *
+ * The commit it is special; it doesn't have any on-disk representation.
+ * When a commit itx is "committed" to an lwb, the waiter associated
+ * with it is linked onto the lwb's list of waiters. Then, when that lwb
+ * completes, each waiter on the lwb's list is marked done and signaled
+ * -- allowing the thread waiting on the waiter to return from zil_commit().
*
- * itxs are committed in batches. In a heavily stressed zil there will be
- * a commit writer thread who is writing out a bunch of itxs to the log
- * for a set of committing threads (cthreads) in the same batch as the writer.
- * Those cthreads are all waiting on the same cv for that batch.
+ * It's important to point out a few critical factors that allow us
+ * to make use of the commit itxs, commit waiters, per-lwb lists of
+ * commit waiters, and zio completion callbacks like we're doing:
*
- * There will also be a different and growing batch of threads that are
- * waiting to commit (qthreads). When the committing batch completes
- * a transition occurs such that the cthreads exit and the qthreads become
- * cthreads. One of the new cthreads becomes the writer thread for the
- * batch. Any new threads arriving become new qthreads.
+ * 1. The list of waiters for each lwb is traversed, and each commit
+ * waiter is marked "done" and signaled, in the zio completion
+ * callback of the lwb's zio[*].
*
- * Only 2 condition variables are needed and there's no transition
- * between the two cvs needed. They just flip-flop between qthreads
- * and cthreads.
+ * * Actually, the waiters are signaled in the zio completion
+ * callback of the root zio for the DKIOCFLUSHWRITECACHE commands
+ * that are sent to the vdevs upon completion of the lwb zio.
*
- * Using this scheme we can efficiently wakeup up only those threads
- * that have been committed.
+ * 2. When the itxs are inserted into the ZIL's queue of uncommitted
+ * itxs, the order in which they are inserted is preserved[*]; as
+ * itxs are added to the queue, they are added to the tail of
+ * in-memory linked lists.
+ *
+ * When committing the itxs to lwbs (to be written to disk), they
+ * are committed in the same order in which the itxs were added to
+ * the uncommitted queue's linked list(s); i.e. the linked list of
+ * itxs to commit is traversed from head to tail, and each itx is
+ * committed to an lwb in that order.
+ *
+ * * To clarify:
+ *
+ * - the order of "sync" itxs is preserved w.r.t. other
+ * "sync" itxs, regardless of the corresponding objects.
+ * - the order of "async" itxs is preserved w.r.t. other
+ * "async" itxs corresponding to the same object.
+ * - the order of "async" itxs is *not* preserved w.r.t. other
+ * "async" itxs corresponding to different objects.
+ * - the order of "sync" itxs w.r.t. "async" itxs (or vice
+ * versa) is *not* preserved, even for itxs that correspond
+ * to the same object.
+ *
+ * For more details, see: zil_itx_assign(), zil_async_to_sync(),
+ * zil_get_commit_list(), and zil_process_commit_list().
+ *
+ * 3. The lwbs represent a linked list of blocks on disk. Thus, any
+ * lwb cannot be considered committed to stable storage, until its
+ * "previous" lwb is also committed to stable storage. This fact,
+ * coupled with the fact described above, means that itxs are
+ * committed in (roughly) the order in which they were generated.
+ * This is essential because itxs are dependent on prior itxs.
+ * Thus, we *must not* deem an itx as being committed to stable
+ * storage, until *all* prior itxs have also been committed to
+ * stable storage.
+ *
+ * To enforce this ordering of lwb zio's, while still leveraging as
+ * much of the underlying storage performance as possible, we rely
+ * on two fundamental concepts:
+ *
+ * 1. The creation and issuance of lwb zio's is protected by
+ * the zilog's "zl_issuer_lock", which ensures only a single
+ * thread is creating and/or issuing lwb's at a time
+ * 2. The "previous" lwb is a child of the "current" lwb
+ * (leveraging the zio parent-child dependency graph)
+ *
+ * By relying on this parent-child zio relationship, we can have
+ * many lwb zio's concurrently issued to the underlying storage,
+ * but the order in which they complete will be the same order in
+ * which they were created.
*/
void
zil_commit(zilog_t *zilog, uint64_t foid)
{
- uint64_t mybatch;
+ /*
+ * We should never attempt to call zil_commit on a snapshot for
+ * a couple of reasons:
+ *
+ * 1. A snapshot may never be modified, thus it cannot have any
+ * in-flight itxs that would have modified the dataset.
+ *
+ * 2. By design, when zil_commit() is called, a commit itx will
+ * be assigned to this zilog; as a result, the zilog will be
+ * dirtied. We must not dirty the zilog of a snapshot; there's
+ * checks in the code that enforce this invariant, and will
+ * cause a panic if it's not upheld.
+ */
+ ASSERT3B(dmu_objset_is_snapshot(zilog->zl_os), ==, B_FALSE);
if (zilog->zl_sync == ZFS_SYNC_DISABLED)
return;
+ if (!spa_writeable(zilog->zl_spa)) {
+ /*
+ * If the SPA is not writable, there should never be any
+ * pending itxs waiting to be committed to disk. If that
+ * weren't true, we'd skip writing those itxs out, and
+ * would break the semantics of zil_commit(); thus, we're
+ * verifying that truth before we return to the caller.
+ */
+ ASSERT(list_is_empty(&zilog->zl_lwb_list));
+ ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL);
+ for (int i = 0; i < TXG_SIZE; i++)
+ ASSERT3P(zilog->zl_itxg[i].itxg_itxs, ==, NULL);
+ return;
+ }
+
+ /*
+ * If the ZIL is suspended, we don't want to dirty it by calling
+ * zil_commit_itx_assign() below, nor can we write out
+ * lwbs like would be done in zil_commit_write(). Thus, we
+ * simply rely on txg_wait_synced() to maintain the necessary
+ * semantics, and avoid calling those functions altogether.
+ */
+ if (zilog->zl_suspend > 0) {
+ txg_wait_synced(zilog->zl_dmu_pool, 0);
+ return;
+ }
+
+ zil_commit_impl(zilog, foid);
+}
+
+void
+zil_commit_impl(zilog_t *zilog, uint64_t foid)
+{
ZIL_STAT_BUMP(zil_commit_count);
- /* move the async itxs for the foid to the sync queues */
+ /*
+ * Move the "async" itxs for the specified foid to the "sync"
+ * queues, such that they will be later committed (or skipped)
+ * to an lwb when zil_process_commit_list() is called.
+ *
+ * Since these "async" itxs must be committed prior to this
+ * call to zil_commit returning, we must perform this operation
+ * before we call zil_commit_itx_assign().
+ */
zil_async_to_sync(zilog, foid);
- mutex_enter(&zilog->zl_lock);
- mybatch = zilog->zl_next_batch;
- while (zilog->zl_writer) {
- cv_wait(&zilog->zl_cv_batch[mybatch & 1], &zilog->zl_lock);
- if (mybatch <= zilog->zl_com_batch) {
- mutex_exit(&zilog->zl_lock);
- return;
- }
- }
-
- zilog->zl_next_batch++;
- zilog->zl_writer = B_TRUE;
- ZIL_STAT_BUMP(zil_commit_writer_count);
- zil_commit_writer(zilog);
- zilog->zl_com_batch = mybatch;
- zilog->zl_writer = B_FALSE;
+ /*
+ * We allocate a new "waiter" structure which will initially be
+ * linked to the commit itx using the itx's "itx_private" field.
+ * Since the commit itx doesn't represent any on-disk state,
+ * when it's committed to an lwb, rather than copying the its
+ * lr_t into the lwb's buffer, the commit itx's "waiter" will be
+ * added to the lwb's list of waiters. Then, when the lwb is
+ * committed to stable storage, each waiter in the lwb's list of
+ * waiters will be marked "done", and signalled.
+ *
+ * We must create the waiter and assign the commit itx prior to
+ * calling zil_commit_writer(), or else our specific commit itx
+ * is not guaranteed to be committed to an lwb prior to calling
+ * zil_commit_waiter().
+ */
+ zil_commit_waiter_t *zcw = zil_alloc_commit_waiter();
+ zil_commit_itx_assign(zilog, zcw);
- /* wake up one thread to become the next writer */
- cv_signal(&zilog->zl_cv_batch[(mybatch+1) & 1]);
+ zil_commit_writer(zilog, zcw);
+ zil_commit_waiter(zilog, zcw);
- /* wake up all threads waiting for this batch to be committed */
- cv_broadcast(&zilog->zl_cv_batch[mybatch & 1]);
+ if (zcw->zcw_zio_error != 0) {
+ /*
+ * If there was an error writing out the ZIL blocks that
+ * this thread is waiting on, then we fallback to
+ * relying on spa_sync() to write out the data this
+ * thread is waiting on. Obviously this has performance
+ * implications, but the expectation is for this to be
+ * an exceptional case, and shouldn't occur often.
+ */
+ DTRACE_PROBE2(zil__commit__io__error,
+ zilog_t *, zilog, zil_commit_waiter_t *, zcw);
+ txg_wait_synced(zilog->zl_dmu_pool, 0);
+ }
- mutex_exit(&zilog->zl_lock);
+ zil_free_commit_waiter(zcw);
}
/*
zh->zh_log = lwb->lwb_blk;
if (lwb->lwb_buf != NULL || lwb->lwb_max_txg > txg)
break;
-
- ASSERT(lwb->lwb_zio == NULL);
-
list_remove(&zilog->zl_lwb_list, lwb);
- zio_free_zil(spa, txg, &lwb->lwb_blk);
- kmem_cache_free(zil_lwb_cache, lwb);
+ zio_free(spa, txg, &lwb->lwb_blk);
+ zil_free_lwb(zilog, lwb);
/*
* If we don't have anything left in the lwb list then
* unused, long-lived LWBs.
*/
for (; lwb != NULL; lwb = list_next(&zilog->zl_lwb_list, lwb)) {
- if (lwb->lwb_fastwrite && !lwb->lwb_zio) {
+ if (lwb->lwb_fastwrite && !lwb->lwb_write_zio) {
metaslab_fastwrite_unmark(zilog->zl_spa, &lwb->lwb_blk);
lwb->lwb_fastwrite = 0;
}
mutex_exit(&zilog->zl_lock);
}
+/* ARGSUSED */
+static int
+zil_lwb_cons(void *vbuf, void *unused, int kmflag)
+{
+ lwb_t *lwb = vbuf;
+ list_create(&lwb->lwb_itxs, sizeof (itx_t), offsetof(itx_t, itx_node));
+ list_create(&lwb->lwb_waiters, sizeof (zil_commit_waiter_t),
+ offsetof(zil_commit_waiter_t, zcw_node));
+ avl_create(&lwb->lwb_vdev_tree, zil_lwb_vdev_compare,
+ sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node));
+ mutex_init(&lwb->lwb_vdev_lock, NULL, MUTEX_DEFAULT, NULL);
+ return (0);
+}
+
+/* ARGSUSED */
+static void
+zil_lwb_dest(void *vbuf, void *unused)
+{
+ lwb_t *lwb = vbuf;
+ mutex_destroy(&lwb->lwb_vdev_lock);
+ avl_destroy(&lwb->lwb_vdev_tree);
+ list_destroy(&lwb->lwb_waiters);
+ list_destroy(&lwb->lwb_itxs);
+}
+
void
zil_init(void)
{
zil_lwb_cache = kmem_cache_create("zil_lwb_cache",
- sizeof (struct lwb), 0, NULL, NULL, NULL, NULL, NULL, 0);
+ sizeof (lwb_t), 0, zil_lwb_cons, zil_lwb_dest, NULL, NULL, NULL, 0);
+
+ zil_zcw_cache = kmem_cache_create("zil_zcw_cache",
+ sizeof (zil_commit_waiter_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
zil_ksp = kstat_create("zfs", 0, "zil", "misc",
- KSTAT_TYPE_NAMED, sizeof(zil_stats) / sizeof(kstat_named_t),
+ KSTAT_TYPE_NAMED, sizeof (zil_stats) / sizeof (kstat_named_t),
KSTAT_FLAG_VIRTUAL);
if (zil_ksp != NULL) {
void
zil_fini(void)
{
+ kmem_cache_destroy(zil_zcw_cache);
kmem_cache_destroy(zil_lwb_cache);
if (zil_ksp != NULL) {
zil_alloc(objset_t *os, zil_header_t *zh_phys)
{
zilog_t *zilog;
- int i;
- zilog = kmem_zalloc(sizeof (zilog_t), KM_PUSHPAGE);
+ zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP);
zilog->zl_header = zh_phys;
zilog->zl_os = os;
zilog->zl_destroy_txg = TXG_INITIAL - 1;
zilog->zl_logbias = dmu_objset_logbias(os);
zilog->zl_sync = dmu_objset_syncprop(os);
- zilog->zl_next_batch = 1;
+ zilog->zl_dirty_max_txg = 0;
+ zilog->zl_last_lwb_opened = NULL;
+ zilog->zl_last_lwb_latency = 0;
mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL);
+ mutex_init(&zilog->zl_issuer_lock, NULL, MUTEX_DEFAULT, NULL);
- for (i = 0; i < TXG_SIZE; i++) {
+ for (int i = 0; i < TXG_SIZE; i++) {
mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL,
MUTEX_DEFAULT, NULL);
}
list_create(&zilog->zl_itx_commit_list, sizeof (itx_t),
offsetof(itx_t, itx_node));
- mutex_init(&zilog->zl_vdev_lock, NULL, MUTEX_DEFAULT, NULL);
-
- avl_create(&zilog->zl_vdev_tree, zil_vdev_compare,
- sizeof (zil_vdev_node_t), offsetof(zil_vdev_node_t, zv_node));
-
- cv_init(&zilog->zl_cv_writer, NULL, CV_DEFAULT, NULL);
cv_init(&zilog->zl_cv_suspend, NULL, CV_DEFAULT, NULL);
- cv_init(&zilog->zl_cv_batch[0], NULL, CV_DEFAULT, NULL);
- cv_init(&zilog->zl_cv_batch[1], NULL, CV_DEFAULT, NULL);
return (zilog);
}
zilog->zl_stop_sync = 1;
+ ASSERT0(zilog->zl_suspend);
+ ASSERT0(zilog->zl_suspending);
+
ASSERT(list_is_empty(&zilog->zl_lwb_list));
list_destroy(&zilog->zl_lwb_list);
- avl_destroy(&zilog->zl_vdev_tree);
- mutex_destroy(&zilog->zl_vdev_lock);
-
ASSERT(list_is_empty(&zilog->zl_itx_commit_list));
list_destroy(&zilog->zl_itx_commit_list);
mutex_destroy(&zilog->zl_itxg[i].itxg_lock);
}
+ mutex_destroy(&zilog->zl_issuer_lock);
mutex_destroy(&zilog->zl_lock);
- cv_destroy(&zilog->zl_cv_writer);
cv_destroy(&zilog->zl_cv_suspend);
- cv_destroy(&zilog->zl_cv_batch[0]);
- cv_destroy(&zilog->zl_cv_batch[1]);
kmem_free(zilog, sizeof (zilog_t));
}
{
zilog_t *zilog = dmu_objset_zil(os);
- ASSERT(zilog->zl_clean_taskq == NULL);
- ASSERT(zilog->zl_get_data == NULL);
+ ASSERT3P(zilog->zl_get_data, ==, NULL);
+ ASSERT3P(zilog->zl_last_lwb_opened, ==, NULL);
ASSERT(list_is_empty(&zilog->zl_lwb_list));
zilog->zl_get_data = get_data;
- zilog->zl_clean_taskq = taskq_create("zil_clean", 1, minclsyspri,
- 2, 2, TASKQ_PREPOPULATE);
return (zilog);
}
zil_close(zilog_t *zilog)
{
lwb_t *lwb;
- uint64_t txg = 0;
+ uint64_t txg;
- zil_commit(zilog, 0); /* commit all itx */
+ if (!dmu_objset_is_snapshot(zilog->zl_os)) {
+ zil_commit(zilog, 0);
+ } else {
+ ASSERT3P(list_tail(&zilog->zl_lwb_list), ==, NULL);
+ ASSERT0(zilog->zl_dirty_max_txg);
+ ASSERT3B(zilog_is_dirty(zilog), ==, B_FALSE);
+ }
- /*
- * The lwb_max_txg for the stubby lwb will reflect the last activity
- * for the zil. After a txg_wait_synced() on the txg we know all the
- * callbacks have occurred that may clean the zil. Only then can we
- * destroy the zl_clean_taskq.
- */
mutex_enter(&zilog->zl_lock);
lwb = list_tail(&zilog->zl_lwb_list);
- if (lwb != NULL)
- txg = lwb->lwb_max_txg;
+ if (lwb == NULL)
+ txg = zilog->zl_dirty_max_txg;
+ else
+ txg = MAX(zilog->zl_dirty_max_txg, lwb->lwb_max_txg);
mutex_exit(&zilog->zl_lock);
- if (txg)
+
+ /*
+ * We need to use txg_wait_synced() to wait long enough for the
+ * ZIL to be clean, and to wait for all pending lwbs to be
+ * written out.
+ */
+ if (txg != 0)
txg_wait_synced(zilog->zl_dmu_pool, txg);
- ASSERT(!zilog_is_dirty(zilog));
- taskq_destroy(zilog->zl_clean_taskq);
- zilog->zl_clean_taskq = NULL;
+ if (zilog_is_dirty(zilog))
+ zfs_dbgmsg("zil (%px) is dirty, txg %llu", zilog, txg);
+ if (txg < spa_freeze_txg(zilog->zl_spa))
+ VERIFY(!zilog_is_dirty(zilog));
+
zilog->zl_get_data = NULL;
/*
- * We should have only one LWB left on the list; remove it now.
+ * We should have only one lwb left on the list; remove it now.
*/
mutex_enter(&zilog->zl_lock);
lwb = list_head(&zilog->zl_lwb_list);
if (lwb != NULL) {
- ASSERT(lwb == list_tail(&zilog->zl_lwb_list));
- ASSERT(lwb->lwb_zio == NULL);
+ ASSERT3P(lwb, ==, list_tail(&zilog->zl_lwb_list));
+ ASSERT3S(lwb->lwb_state, !=, LWB_STATE_ISSUED);
+
if (lwb->lwb_fastwrite)
metaslab_fastwrite_unmark(zilog->zl_spa, &lwb->lwb_blk);
+
list_remove(&zilog->zl_lwb_list, lwb);
zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
- kmem_cache_free(zil_lwb_cache, lwb);
+ zil_free_lwb(zilog, lwb);
}
mutex_exit(&zilog->zl_lock);
}
+static char *suspend_tag = "zil suspending";
+
/*
* Suspend an intent log. While in suspended mode, we still honor
* synchronous semantics, but we rely on txg_wait_synced() to do it.
- * We suspend the log briefly when taking a snapshot so that the snapshot
- * contains all the data it's supposed to, and has an empty intent log.
+ * On old version pools, we suspend the log briefly when taking a
+ * snapshot so that it will have an empty intent log.
+ *
+ * Long holds are not really intended to be used the way we do here --
+ * held for such a short time. A concurrent caller of dsl_dataset_long_held()
+ * could fail. Therefore we take pains to only put a long hold if it is
+ * actually necessary. Fortunately, it will only be necessary if the
+ * objset is currently mounted (or the ZVOL equivalent). In that case it
+ * will already have a long hold, so we are not really making things any worse.
+ *
+ * Ideally, we would locate the existing long-holder (i.e. the zfsvfs_t or
+ * zvol_state_t), and use their mechanism to prevent their hold from being
+ * dropped (e.g. VFS_HOLD()). However, that would be even more pain for
+ * very little gain.
+ *
+ * if cookiep == NULL, this does both the suspend & resume.
+ * Otherwise, it returns with the dataset "long held", and the cookie
+ * should be passed into zil_resume().
*/
int
-zil_suspend(zilog_t *zilog)
+zil_suspend(const char *osname, void **cookiep)
{
- const zil_header_t *zh = zilog->zl_header;
+ objset_t *os;
+ zilog_t *zilog;
+ const zil_header_t *zh;
+ int error;
+
+ error = dmu_objset_hold(osname, suspend_tag, &os);
+ if (error != 0)
+ return (error);
+ zilog = dmu_objset_zil(os);
mutex_enter(&zilog->zl_lock);
+ zh = zilog->zl_header;
+
if (zh->zh_flags & ZIL_REPLAY_NEEDED) { /* unplayed log */
mutex_exit(&zilog->zl_lock);
- return (EBUSY);
+ dmu_objset_rele(os, suspend_tag);
+ return (SET_ERROR(EBUSY));
}
- if (zilog->zl_suspend++ != 0) {
+
+ /*
+ * Don't put a long hold in the cases where we can avoid it. This
+ * is when there is no cookie so we are doing a suspend & resume
+ * (i.e. called from zil_vdev_offline()), and there's nothing to do
+ * for the suspend because it's already suspended, or there's no ZIL.
+ */
+ if (cookiep == NULL && !zilog->zl_suspending &&
+ (zilog->zl_suspend > 0 || BP_IS_HOLE(&zh->zh_log))) {
+ mutex_exit(&zilog->zl_lock);
+ dmu_objset_rele(os, suspend_tag);
+ return (0);
+ }
+
+ dsl_dataset_long_hold(dmu_objset_ds(os), suspend_tag);
+ dsl_pool_rele(dmu_objset_pool(os), suspend_tag);
+
+ zilog->zl_suspend++;
+
+ if (zilog->zl_suspend > 1) {
/*
- * Someone else already began a suspend.
+ * Someone else is already suspending it.
* Just wait for them to finish.
*/
+
while (zilog->zl_suspending)
cv_wait(&zilog->zl_cv_suspend, &zilog->zl_lock);
mutex_exit(&zilog->zl_lock);
+
+ if (cookiep == NULL)
+ zil_resume(os);
+ else
+ *cookiep = os;
+ return (0);
+ }
+
+ /*
+ * If there is no pointer to an on-disk block, this ZIL must not
+ * be active (e.g. filesystem not mounted), so there's nothing
+ * to clean up.
+ */
+ if (BP_IS_HOLE(&zh->zh_log)) {
+ ASSERT(cookiep != NULL); /* fast path already handled */
+
+ *cookiep = os;
+ mutex_exit(&zilog->zl_lock);
return (0);
}
+
+ /*
+ * The ZIL has work to do. Ensure that the associated encryption
+ * key will remain mapped while we are committing the log by
+ * grabbing a reference to it. If the key isn't loaded we have no
+ * choice but to return an error until the wrapping key is loaded.
+ */
+ if (os->os_encrypted &&
+ dsl_dataset_create_key_mapping(dmu_objset_ds(os)) != 0) {
+ zilog->zl_suspend--;
+ mutex_exit(&zilog->zl_lock);
+ dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
+ dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
+ return (SET_ERROR(EACCES));
+ }
+
zilog->zl_suspending = B_TRUE;
mutex_exit(&zilog->zl_lock);
- zil_commit(zilog, 0);
+ /*
+ * We need to use zil_commit_impl to ensure we wait for all
+ * LWB_STATE_OPENED and LWB_STATE_ISSUED lwbs to be committed
+ * to disk before proceeding. If we used zil_commit instead, it
+ * would just call txg_wait_synced(), because zl_suspend is set.
+ * txg_wait_synced() doesn't wait for these lwb's to be
+ * LWB_STATE_FLUSH_DONE before returning.
+ */
+ zil_commit_impl(zilog, 0);
+
+ /*
+ * Now that we've ensured all lwb's are LWB_STATE_FLUSH_DONE, we
+ * use txg_wait_synced() to ensure the data from the zilog has
+ * migrated to the main pool before calling zil_destroy().
+ */
+ txg_wait_synced(zilog->zl_dmu_pool, 0);
zil_destroy(zilog, B_FALSE);
cv_broadcast(&zilog->zl_cv_suspend);
mutex_exit(&zilog->zl_lock);
+ if (os->os_encrypted)
+ dsl_dataset_remove_key_mapping(dmu_objset_ds(os));
+
+ if (cookiep == NULL)
+ zil_resume(os);
+ else
+ *cookiep = os;
return (0);
}
void
-zil_resume(zilog_t *zilog)
+zil_resume(void *cookie)
{
+ objset_t *os = cookie;
+ zilog_t *zilog = dmu_objset_zil(os);
+
mutex_enter(&zilog->zl_lock);
ASSERT(zilog->zl_suspend != 0);
zilog->zl_suspend--;
mutex_exit(&zilog->zl_lock);
+ dsl_dataset_long_rele(dmu_objset_ds(os), suspend_tag);
+ dsl_dataset_rele(dmu_objset_ds(os), suspend_tag);
}
typedef struct zil_replay_arg {
- zil_replay_func_t *zr_replay;
+ zil_replay_func_t **zr_replay;
void *zr_arg;
boolean_t zr_byteswap;
char *zr_lr;
static int
zil_replay_error(zilog_t *zilog, lr_t *lr, int error)
{
- char name[MAXNAMELEN];
+ char name[ZFS_MAX_DATASET_NAME_LEN];
zilog->zl_replaying_seq--; /* didn't actually replay this one */
*/
if (TX_OOO(txtype)) {
error = dmu_object_info(zilog->zl_os,
- ((lr_ooo_t *)lr)->lr_foid, NULL);
+ LR_FOID_GET_OBJ(((lr_ooo_t *)lr)->lr_foid), NULL);
if (error == ENOENT || error == EEXIST)
return (0);
}
if (txtype == TX_WRITE && reclen == sizeof (lr_write_t)) {
error = zil_read_log_data(zilog, (lr_write_t *)lr,
zr->zr_lr + reclen);
- if (error)
+ if (error != 0)
return (zil_replay_error(zilog, lr, error));
}
* is updated if we are in replay mode.
*/
error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, zr->zr_byteswap);
- if (error) {
+ if (error != 0) {
/*
* The DMU's dnode layer doesn't see removes until the txg
* commits, so a subsequent claim can spuriously fail with
*/
txg_wait_synced(spa_get_dsl(zilog->zl_spa), 0);
error = zr->zr_replay[txtype](zr->zr_arg, zr->zr_lr, B_FALSE);
- if (error)
+ if (error != 0)
return (zil_replay_error(zilog, lr, error));
}
return (0);
* If this dataset has a non-empty intent log, replay it and destroy it.
*/
void
-zil_replay(objset_t *os, void *arg, zil_replay_func_t replay_func[TX_MAX_TYPE])
+zil_replay(objset_t *os, void *arg, zil_replay_func_t *replay_func[TX_MAX_TYPE])
{
zilog_t *zilog = dmu_objset_zil(os);
const zil_header_t *zh = zilog->zl_header;
zr.zr_replay = replay_func;
zr.zr_arg = arg;
zr.zr_byteswap = BP_SHOULD_BYTESWAP(&zh->zh_log);
- zr.zr_lr = vmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_PUSHPAGE);
+ zr.zr_lr = vmem_alloc(2 * SPA_MAXBLOCKSIZE, KM_SLEEP);
/*
* Wait for in-progress removes to sync before starting replay.
zilog->zl_replay_time = ddi_get_lbolt();
ASSERT(zilog->zl_replay_blks == 0);
(void) zil_parse(zilog, zil_incr_blks, zil_replay_log_record, &zr,
- zh->zh_claim_txg);
+ zh->zh_claim_txg, B_TRUE);
vmem_free(zr.zr_lr, 2 * SPA_MAXBLOCKSIZE);
zil_destroy(zilog, B_FALSE);
/* ARGSUSED */
int
-zil_vdev_offline(const char *osname, void *arg)
+zil_reset(const char *osname, void *arg)
{
- objset_t *os;
- zilog_t *zilog;
int error;
- error = dmu_objset_hold(osname, FTAG, &os);
- if (error)
- return (error);
-
- zilog = dmu_objset_zil(os);
- if (zil_suspend(zilog) != 0)
- error = EEXIST;
- else
- zil_resume(zilog);
- dmu_objset_rele(os, FTAG);
- return (error);
+ error = zil_suspend(osname, NULL);
+ /* EACCES means crypto key not loaded */
+ if ((error == EACCES) || (error == EBUSY))
+ return (SET_ERROR(error));
+ if (error != 0)
+ return (SET_ERROR(EEXIST));
+ return (0);
}
-#if defined(_KERNEL) && defined(HAVE_SPL)
+#if defined(_KERNEL)
+EXPORT_SYMBOL(zil_alloc);
+EXPORT_SYMBOL(zil_free);
+EXPORT_SYMBOL(zil_open);
+EXPORT_SYMBOL(zil_close);
+EXPORT_SYMBOL(zil_replay);
+EXPORT_SYMBOL(zil_replaying);
+EXPORT_SYMBOL(zil_destroy);
+EXPORT_SYMBOL(zil_destroy_sync);
+EXPORT_SYMBOL(zil_itx_create);
+EXPORT_SYMBOL(zil_itx_destroy);
+EXPORT_SYMBOL(zil_itx_assign);
+EXPORT_SYMBOL(zil_commit);
+EXPORT_SYMBOL(zil_claim);
+EXPORT_SYMBOL(zil_check_log_chain);
+EXPORT_SYMBOL(zil_sync);
+EXPORT_SYMBOL(zil_clean);
+EXPORT_SYMBOL(zil_suspend);
+EXPORT_SYMBOL(zil_resume);
+EXPORT_SYMBOL(zil_lwb_add_block);
+EXPORT_SYMBOL(zil_bp_tree_add);
+EXPORT_SYMBOL(zil_set_sync);
+EXPORT_SYMBOL(zil_set_logbias);
+
+/* BEGIN CSTYLED */
+module_param(zfs_commit_timeout_pct, int, 0644);
+MODULE_PARM_DESC(zfs_commit_timeout_pct, "ZIL block open timeout percentage");
+
module_param(zil_replay_disable, int, 0644);
MODULE_PARM_DESC(zil_replay_disable, "Disable intent logging replay");
-module_param(zfs_nocacheflush, int, 0644);
-MODULE_PARM_DESC(zfs_nocacheflush, "Disable cache flushes");
+module_param(zil_nocacheflush, int, 0644);
+MODULE_PARM_DESC(zil_nocacheflush, "Disable ZIL cache flushes");
-module_param(zil_slog_limit, ulong, 0644);
-MODULE_PARM_DESC(zil_slog_limit, "Max commit bytes to separate log device");
+module_param(zil_slog_bulk, ulong, 0644);
+MODULE_PARM_DESC(zil_slog_bulk, "Limit in bytes slog sync writes per commit");
+/* END CSTYLED */
#endif
projects / mirror_zfs.git / blobdiff