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Improve rate at which new zvols are processed

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The kernel function which adds new zvols as disks to the system,
add_disk(), briefly opens and closes the zvol as part of its work.
Closing a zvol involves waiting for two txgs to sync. This, combined
with the fact that the taskq processing new zvols is single threaded,
makes this processing new zvols slow.

Waiting for these txgs to sync is only necessary if the zvol has been
written to, which is not the case during add_disk(). This change adds
tracking of whether a zvol has been written to so that we can skip the
txg_wait_synced() calls when they are unnecessary.

This change also fixes the flags passed to blkdev_get_by_path() by
vdev_disk_open() to be FMODE_READ | FMODE_WRITE | FMODE_EXCL instead of
just FMODE_EXCL. The flags were being incorrectly calculated because
we were using the wrong version of vdev_bdev_mode().

Reviewed-by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: John Gallagher <john.gallagher@delphix.com>
Closes #8526 
Closes #8615
This commit is contained in:
John Gallagher 2019-05-04 16:39:10 -07:00 committed by Brian Behlendorf
parent b3b60984ee
commit 1eacf2b3b0
2 changed files with 146 additions and 116 deletions
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4
module/zfs/vdev_disk.c
View File

@ -23,7 +23,7 @@
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Rewritten for Linux by Brian Behlendorf <behlendorf1@llnl.gov>.
* LLNL-CODE-403049.
* Copyright (c) 2012, 2018 by Delphix. All rights reserved.
* Copyright (c) 2012, 2019 by Delphix. All rights reserved.
*/
#include <sys/zfs_context.h>
@ -56,7 +56,7 @@ typedef struct dio_request {
} dio_request_t;
#ifdef HAVE_OPEN_BDEV_EXCLUSIVE
#if defined(HAVE_OPEN_BDEV_EXCLUSIVE) || defined(HAVE_BLKDEV_GET_BY_PATH)
static fmode_t
vdev_bdev_mode(int smode)
{

258
module/zfs/zvol.c
View File

@ -36,7 +36,7 @@
*
* Copyright 2014 Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2016 Actifio, Inc. All rights reserved.
* Copyright (c) 2012, 2018 by Delphix. All rights reserved.
* Copyright (c) 2012, 2019 by Delphix. All rights reserved.
*/
/*
@ -155,6 +155,11 @@ typedef struct {
} zvol_task_t;
#define ZVOL_RDONLY 0x1
/*
* Whether the zvol has been written to (as opposed to ZVOL_RDONLY, which
* specifies whether or not the zvol _can_ be written to)
*/
#define ZVOL_WRITTEN_TO 0x2
static uint64_t
zvol_name_hash(const char *name)
@ -742,6 +747,7 @@ zvol_write(void *arg)
zvol_state_t *zv = zvr->zv;
ASSERT(zv && zv->zv_open_count > 0);
ASSERT(zv->zv_zilog != NULL);
ssize_t start_resid = uio.uio_resid;
unsigned long start_jif = jiffies;
@ -832,6 +838,7 @@ zvol_discard(void *arg)
unsigned long start_jif;
ASSERT(zv && zv->zv_open_count > 0);
ASSERT(zv->zv_zilog != NULL);
start_jif = jiffies;
blk_generic_start_io_acct(zv->zv_queue, WRITE, bio_sectors(bio),
@ -930,116 +937,6 @@ zvol_read(void *arg)
kmem_free(zvr, sizeof (zv_request_t));
}
static MAKE_REQUEST_FN_RET
zvol_request(struct request_queue *q, struct bio *bio)
{
zvol_state_t *zv = q->queuedata;
fstrans_cookie_t cookie = spl_fstrans_mark();
uint64_t offset = BIO_BI_SECTOR(bio) << 9;
uint64_t size = BIO_BI_SIZE(bio);
int rw = bio_data_dir(bio);
zv_request_t *zvr;
if (bio_has_data(bio) && offset + size > zv->zv_volsize) {
printk(KERN_INFO
"%s: bad access: offset=%llu, size=%lu\n",
zv->zv_disk->disk_name,
(long long unsigned)offset,
(long unsigned)size);
BIO_END_IO(bio, -SET_ERROR(EIO));
goto out;
}
if (rw == WRITE) {
boolean_t need_sync = B_FALSE;
if (unlikely(zv->zv_flags & ZVOL_RDONLY)) {
BIO_END_IO(bio, -SET_ERROR(EROFS));
goto out;
}
/*
* To be released in the I/O function. See the comment on
* rangelock_enter() below.
*/
rw_enter(&zv->zv_suspend_lock, RW_READER);
/* bio marked as FLUSH need to flush before write */
if (bio_is_flush(bio))
zil_commit(zv->zv_zilog, ZVOL_OBJ);
/* Some requests are just for flush and nothing else. */
if (size == 0) {
rw_exit(&zv->zv_suspend_lock);
BIO_END_IO(bio, 0);
goto out;
}
zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
zvr->zv = zv;
zvr->bio = bio;
/*
* To be released in the I/O function. Since the I/O functions
* are asynchronous, we take it here synchronously to make
* sure overlapped I/Os are properly ordered.
*/
zvr->lr = rangelock_enter(&zv->zv_rangelock, offset, size,
RL_WRITER);
/*
* Sync writes and discards execute zil_commit() which may need
* to take a RL_READER lock on the whole block being modified
* via its zillog->zl_get_data(): to avoid circular dependency
* issues with taskq threads execute these requests
* synchronously here in zvol_request().
*/
need_sync = bio_is_fua(bio) ||
zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
if (bio_is_discard(bio) || bio_is_secure_erase(bio)) {
if (zvol_request_sync || need_sync ||
taskq_dispatch(zvol_taskq, zvol_discard, zvr,
TQ_SLEEP) == TASKQID_INVALID)
zvol_discard(zvr);
} else {
if (zvol_request_sync || need_sync ||
taskq_dispatch(zvol_taskq, zvol_write, zvr,
TQ_SLEEP) == TASKQID_INVALID)
zvol_write(zvr);
}
} else {
/*
* The SCST driver, and possibly others, may issue READ I/Os
* with a length of zero bytes. These empty I/Os contain no
* data and require no additional handling.
*/
if (size == 0) {
BIO_END_IO(bio, 0);
goto out;
}
zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
zvr->zv = zv;
zvr->bio = bio;
rw_enter(&zv->zv_suspend_lock, RW_READER);
zvr->lr = rangelock_enter(&zv->zv_rangelock, offset, size,
RL_READER);
if (zvol_request_sync || taskq_dispatch(zvol_taskq,
zvol_read, zvr, TQ_SLEEP) == TASKQID_INVALID)
zvol_read(zvr);
}
out:
spl_fstrans_unmark(cookie);
#ifdef HAVE_MAKE_REQUEST_FN_RET_INT
return (0);
#elif defined(HAVE_MAKE_REQUEST_FN_RET_QC)
return (BLK_QC_T_NONE);
#endif
}
/* ARGSUSED */
static void
zvol_get_done(zgd_t *zgd, int error)
@ -1120,6 +1017,133 @@ zvol_get_data(void *arg, lr_write_t *lr, char *buf, struct lwb *lwb, zio_t *zio)
return (SET_ERROR(error));
}
static MAKE_REQUEST_FN_RET
zvol_request(struct request_queue *q, struct bio *bio)
{
zvol_state_t *zv = q->queuedata;
fstrans_cookie_t cookie = spl_fstrans_mark();
uint64_t offset = BIO_BI_SECTOR(bio) << 9;
uint64_t size = BIO_BI_SIZE(bio);
int rw = bio_data_dir(bio);
zv_request_t *zvr;
if (bio_has_data(bio) && offset + size > zv->zv_volsize) {
printk(KERN_INFO
"%s: bad access: offset=%llu, size=%lu\n",
zv->zv_disk->disk_name,
(long long unsigned)offset,
(long unsigned)size);
BIO_END_IO(bio, -SET_ERROR(EIO));
goto out;
}
if (rw == WRITE) {
boolean_t need_sync = B_FALSE;
if (unlikely(zv->zv_flags & ZVOL_RDONLY)) {
BIO_END_IO(bio, -SET_ERROR(EROFS));
goto out;
}
/*
* To be released in the I/O function. See the comment on
* rangelock_enter() below.
*/
rw_enter(&zv->zv_suspend_lock, RW_READER);
/*
* Open a ZIL if this is the first time we have written to this
* zvol. We protect zv->zv_zilog with zv_suspend_lock rather
* than zv_state_lock so that we don't need to acquire an
* additional lock in this path.
*/
if (zv->zv_zilog == NULL) {
rw_exit(&zv->zv_suspend_lock);
rw_enter(&zv->zv_suspend_lock, RW_WRITER);
if (zv->zv_zilog == NULL) {
zv->zv_zilog = zil_open(zv->zv_objset,
zvol_get_data);
zv->zv_flags |= ZVOL_WRITTEN_TO;
}
rw_downgrade(&zv->zv_suspend_lock);
}
/* bio marked as FLUSH need to flush before write */
if (bio_is_flush(bio))
zil_commit(zv->zv_zilog, ZVOL_OBJ);
/* Some requests are just for flush and nothing else. */
if (size == 0) {
rw_exit(&zv->zv_suspend_lock);
BIO_END_IO(bio, 0);
goto out;
}
zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
zvr->zv = zv;
zvr->bio = bio;
/*
* To be released in the I/O function. Since the I/O functions
* are asynchronous, we take it here synchronously to make
* sure overlapped I/Os are properly ordered.
*/
zvr->lr = rangelock_enter(&zv->zv_rangelock, offset, size,
RL_WRITER);
/*
* Sync writes and discards execute zil_commit() which may need
* to take a RL_READER lock on the whole block being modified
* via its zillog->zl_get_data(): to avoid circular dependency
* issues with taskq threads execute these requests
* synchronously here in zvol_request().
*/
need_sync = bio_is_fua(bio) ||
zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
if (bio_is_discard(bio) || bio_is_secure_erase(bio)) {
if (zvol_request_sync || need_sync ||
taskq_dispatch(zvol_taskq, zvol_discard, zvr,
TQ_SLEEP) == TASKQID_INVALID)
zvol_discard(zvr);
} else {
if (zvol_request_sync || need_sync ||
taskq_dispatch(zvol_taskq, zvol_write, zvr,
TQ_SLEEP) == TASKQID_INVALID)
zvol_write(zvr);
}
} else {
/*
* The SCST driver, and possibly others, may issue READ I/Os
* with a length of zero bytes. These empty I/Os contain no
* data and require no additional handling.
*/
if (size == 0) {
BIO_END_IO(bio, 0);
goto out;
}
zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
zvr->zv = zv;
zvr->bio = bio;
rw_enter(&zv->zv_suspend_lock, RW_READER);
zvr->lr = rangelock_enter(&zv->zv_rangelock, offset, size,
RL_READER);
if (zvol_request_sync || taskq_dispatch(zvol_taskq,
zvol_read, zvr, TQ_SLEEP) == TASKQID_INVALID)
zvol_read(zvr);
}
out:
spl_fstrans_unmark(cookie);
#ifdef HAVE_MAKE_REQUEST_FN_RET_INT
return (0);
#elif defined(HAVE_MAKE_REQUEST_FN_RET_QC)
return (BLK_QC_T_NONE);
#endif
}
/*
* The zvol_state_t's are inserted into zvol_state_list and zvol_htable.
*/
@ -1157,6 +1181,9 @@ zvol_setup_zv(zvol_state_t *zv)
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
ASSERT(RW_LOCK_HELD(&zv->zv_suspend_lock));
zv->zv_zilog = NULL;
zv->zv_flags &= ~ZVOL_WRITTEN_TO;
error = dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL);
if (error)
return (SET_ERROR(error));
@ -1171,7 +1198,6 @@ zvol_setup_zv(zvol_state_t *zv)
set_capacity(zv->zv_disk, volsize >> 9);
zv->zv_volsize = volsize;
zv->zv_zilog = zil_open(os, zvol_get_data);
if (ro || dmu_objset_is_snapshot(os) ||
!spa_writeable(dmu_objset_spa(os))) {
@ -1194,7 +1220,11 @@ zvol_shutdown_zv(zvol_state_t *zv)
ASSERT(MUTEX_HELD(&zv->zv_state_lock) &&
RW_LOCK_HELD(&zv->zv_suspend_lock));
zil_close(zv->zv_zilog);
if (zv->zv_flags & ZVOL_WRITTEN_TO) {
ASSERT(zv->zv_zilog != NULL);
zil_close(zv->zv_zilog);
}
zv->zv_zilog = NULL;
dnode_rele(zv->zv_dn, FTAG);
@ -1204,7 +1234,7 @@ zvol_shutdown_zv(zvol_state_t *zv)
* Evict cached data. We must write out any dirty data before
* disowning the dataset.
*/
if (!(zv->zv_flags & ZVOL_RDONLY))
if (zv->zv_flags & ZVOL_WRITTEN_TO)
txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
(void) dmu_objset_evict_dbufs(zv->zv_objset);
}