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[Qemu-devel] [PATCH 2/2] block: add filter driver to block/write-thresho
|
From: |
Manos Pitsidianakis |
|
Subject: |
[Qemu-devel] [PATCH 2/2] block: add filter driver to block/write-threshold.c |
|
Date: |
Tue, 15 Aug 2017 09:19:21 +0300 |
With runtime insertion and removal of filters, write-threshold.c can
provide more flexible deliveries of BLOCK_WRITE_THRESHOLD events. After
the event trigger, the filter nodes are no longer useful and must be
removed.
The existing write-threshold cannot be easily converted to using the
filter driver, so it is not affected.
Signed-off-by: Manos Pitsidianakis <address@hidden>
---
block/qapi.c | 2 +-
block/write-threshold.c | 264 +++++++++++++++++++++++++++++++++++-----
include/block/write-threshold.h | 22 ++--
qapi/block-core.json | 19 ++-
tests/test-write-threshold.c | 40 +++---
5 files changed, 281 insertions(+), 66 deletions(-)
diff --git a/block/qapi.c b/block/qapi.c
index 2be44a6758..fe6cf2eae5 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -122,7 +122,7 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
info->group = g_strdup(throttle_group_get_name(tgm));
}
- info->write_threshold = bdrv_write_threshold_get(bs);
+ info->write_threshold = bdrv_write_threshold_get_legacy(bs);
bs0 = bs;
p_image_info = &info->image;
diff --git a/block/write-threshold.c b/block/write-threshold.c
index 0bd1a01c86..4a67188ea3 100644
--- a/block/write-threshold.c
+++ b/block/write-threshold.c
@@ -2,9 +2,11 @@
* QEMU System Emulator block write threshold notification
*
* Copyright Red Hat, Inc. 2014
+ * Copyright 2017 Manos Pitsidianakis
*
* Authors:
* Francesco Romani <address@hidden>
+ * Manos Pitsidianakis <address@hidden>
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
@@ -19,46 +21,35 @@
#include "qmp-commands.h"
-uint64_t bdrv_write_threshold_get(const BlockDriverState *bs)
+uint64_t bdrv_write_threshold_get_legacy(const BlockDriverState *bs)
{
return bs->write_threshold_offset;
}
-bool bdrv_write_threshold_is_set(const BlockDriverState *bs)
+bool bdrv_write_threshold_is_set_legacy(const BlockDriverState *bs)
{
return bs->write_threshold_offset > 0;
}
-static void write_threshold_disable(BlockDriverState *bs)
+static void write_threshold_disable_legacy(BlockDriverState *bs)
{
- if (bdrv_write_threshold_is_set(bs)) {
+ if (bdrv_write_threshold_is_set_legacy(bs)) {
notifier_with_return_remove(&bs->write_threshold_notifier);
bs->write_threshold_offset = 0;
}
}
-uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs,
- const BdrvTrackedRequest *req)
-{
- if (bdrv_write_threshold_is_set(bs)) {
- if (req->offset > bs->write_threshold_offset) {
- return (req->offset - bs->write_threshold_offset) + req->bytes;
- }
- if ((req->offset + req->bytes) > bs->write_threshold_offset) {
- return (req->offset + req->bytes) - bs->write_threshold_offset;
- }
- }
- return 0;
-}
-
static int coroutine_fn before_write_notify(NotifierWithReturn *notifier,
void *opaque)
{
BdrvTrackedRequest *req = opaque;
BlockDriverState *bs = req->bs;
uint64_t amount = 0;
+ uint64_t threshold = bdrv_write_threshold_get_legacy(bs);
+ uint64_t offset = req->offset;
+ uint64_t bytes = req->bytes;
- amount = bdrv_write_threshold_exceeded(bs, req);
+ amount = bdrv_write_threshold_exceeded(threshold, offset, bytes);
if (amount > 0) {
qapi_event_send_block_write_threshold(
bs->node_name,
@@ -67,7 +58,7 @@ static int coroutine_fn
before_write_notify(NotifierWithReturn *notifier,
&error_abort);
/* autodisable to avoid flooding the monitor */
- write_threshold_disable(bs);
+ write_threshold_disable_legacy(bs);
}
return 0; /* should always let other notifiers run */
@@ -79,25 +70,26 @@ static void
write_threshold_register_notifier(BlockDriverState *bs)
bdrv_add_before_write_notifier(bs, &bs->write_threshold_notifier);
}
-static void write_threshold_update(BlockDriverState *bs,
- int64_t threshold_bytes)
+static void write_threshold_update_legacy(BlockDriverState *bs,
+ int64_t threshold_bytes)
{
bs->write_threshold_offset = threshold_bytes;
}
-void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes)
+void bdrv_write_threshold_set_legacy(BlockDriverState *bs,
+ uint64_t threshold_bytes)
{
- if (bdrv_write_threshold_is_set(bs)) {
+ if (bdrv_write_threshold_is_set_legacy(bs)) {
if (threshold_bytes > 0) {
- write_threshold_update(bs, threshold_bytes);
+ write_threshold_update_legacy(bs, threshold_bytes);
} else {
- write_threshold_disable(bs);
+ write_threshold_disable_legacy(bs);
}
} else {
if (threshold_bytes > 0) {
/* avoid multiple registration */
write_threshold_register_notifier(bs);
- write_threshold_update(bs, threshold_bytes);
+ write_threshold_update_legacy(bs, threshold_bytes);
}
/* discard bogus disable request */
}
@@ -119,7 +111,223 @@ void qmp_block_set_write_threshold(const char *node_name,
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
- bdrv_write_threshold_set(bs, threshold_bytes);
+ bdrv_write_threshold_set_legacy(bs, threshold_bytes);
aio_context_release(aio_context);
}
+
+
+/* The write-threshold filter drivers delivers a one-time BLOCK_WRITE_THRESHOLD
+ * event when a passing write request exceeds the configured write threshold
+ * offset of the filter.
+ *
+ * This is useful to transparently resize thin-provisioned drives without
+ * the guest OS noticing.
+ */
+
+#define QEMU_OPT_WRITE_THRESHOLD "write-threshold"
+static BlockDriver write_threshold;
+static QemuOptsList write_threshold_opts = {
+ .name = "write-threshold",
+ .head = QTAILQ_HEAD_INITIALIZER(write_threshold_opts.head),
+ .desc = {
+ {
+ .name = QEMU_OPT_WRITE_THRESHOLD,
+ .type = QEMU_OPT_NUMBER,
+ .help = "configured threshold for the block device, bytes. Use 0"
+ "to disable the threshold",
+ },
+ { /* end of list */ }
+ },
+};
+
+static bool bdrv_write_threshold_is_set(const BlockDriverState *bs)
+{
+ uint64_t threshold = *(uint64_t *)bs->opaque;
+ return threshold > 0;
+}
+
+static void bdrv_write_threshold_disable(BlockDriverState *bs)
+{
+ uint64_t *threshold = (uint64_t *)bs->opaque;
+ if (bdrv_write_threshold_is_set(bs)) {
+ *threshold = 0;
+ }
+}
+
+uint64_t bdrv_write_threshold_exceeded(uint64_t threshold, uint64_t offset,
+ uint64_t bytes)
+{
+ if (threshold) {
+ if (offset > threshold) {
+ return (offset - threshold) + bytes;
+ }
+ if ((offset + bytes) > threshold) {
+ return (offset + bytes) - threshold;
+ }
+ }
+ return 0;
+}
+
+
+static void bdrv_write_threshold_update(BlockDriverState *bs,
+ int64_t threshold_bytes)
+{
+ uint64_t *threshold = (uint64_t *)bs->opaque;
+ *threshold = threshold_bytes;
+}
+
+static void bdrv_write_threshold_check_amount(BlockDriverState *bs,
+ uint64_t offset,
+ uint64_t bytes)
+{
+ uint64_t threshold = *(uint64_t *)bs->opaque;
+ uint64_t amount = 0;
+
+ amount = bdrv_write_threshold_exceeded(threshold, offset, bytes);
+ if (amount > 0) {
+ qapi_event_send_block_write_threshold(child_bs(bs)->node_name,
+ amount,
+ threshold,
+ &error_abort);
+ /* autodisable to avoid flooding the monitor */
+ bdrv_write_threshold_disable(bs);
+ }
+}
+
+/* Filter driver methods */
+
+static int coroutine_fn write_threshold_co_preadv(BlockDriverState *bs,
+ uint64_t offset,
+ uint64_t bytes,
+ QEMUIOVector *qiov,
+ int flags)
+{
+ return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
+}
+
+static int coroutine_fn write_threshold_co_pwritev(BlockDriverState *bs,
+ uint64_t offset,
+ uint64_t bytes,
+ QEMUIOVector *qiov,
+ int flags)
+{
+ bdrv_write_threshold_check_amount(bs, offset, bytes);
+ return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
+}
+
+static int coroutine_fn write_threshold_co_pwrite_zeroes(
+ BlockDriverState *bs,
+ int64_t offset,
+ int bytes,
+ BdrvRequestFlags flags)
+{
+ bdrv_write_threshold_check_amount(bs, offset, bytes);
+ return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
+}
+
+static int coroutine_fn write_threshold_co_pdiscard(BlockDriverState *bs,
+ int64_t offset, int bytes)
+{
+ bdrv_write_threshold_check_amount(bs, offset, bytes);
+ return bdrv_co_pdiscard(bs->file->bs, offset, bytes);
+}
+
+
+static int64_t write_threshold_getlength(BlockDriverState *bs)
+{
+ return bdrv_getlength(bs->file->bs);
+}
+
+static int write_threshold_open(BlockDriverState *bs, QDict *options,
+ int flags, Error **errp)
+{
+ Error *local_err = NULL;
+ int ret = 0;
+ QemuOpts *opts = NULL;
+ uint64_t threshold = 0;
+
+ bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+ false, errp);
+ if (!bs->file) {
+ return -EINVAL;
+ }
+
+ bs->supported_write_flags = bs->file->bs->supported_write_flags;
+ bs->supported_zero_flags = bs->file->bs->supported_zero_flags;
+
+ opts = qemu_opts_create(&write_threshold_opts, NULL, 0, &error_abort);
+
+ qemu_opts_absorb_qdict(opts, options, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ ret = -EINVAL;
+ goto ret;
+ }
+
+ threshold = qemu_opt_get_number(opts, QEMU_OPT_WRITE_THRESHOLD, 0);
+ bdrv_write_threshold_update(bs, threshold);
+
+ret:
+ qemu_opts_del(opts);
+ return ret;
+}
+
+static void write_threshold_close(BlockDriverState *bs)
+{
+}
+
+static int write_threshold_co_flush(BlockDriverState *bs)
+{
+ return bdrv_co_flush(bs->file->bs);
+}
+
+static int64_t coroutine_fn write_threshold_co_get_block_status(
+ BlockDriverState *bs,
+ int64_t sector_num,
+ int nb_sectors,
+ int *pnum,
+ BlockDriverState **file)
+{
+ assert(child_bs(bs));
+ *pnum = nb_sectors;
+ *file = child_bs(bs);
+ return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID |
+ (sector_num << BDRV_SECTOR_BITS);
+}
+
+static bool write_threshold_recurse_is_first_non_filter(
+ BlockDriverState *bs,
+ BlockDriverState *candidate)
+{
+ return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate);
+}
+
+static BlockDriver write_threshold = {
+ .format_name = "write-threshold",
+ .instance_size = sizeof(uint64_t),
+
+ .bdrv_open = write_threshold_open,
+ .bdrv_close = write_threshold_close,
+
+ .bdrv_co_flush = write_threshold_co_flush,
+ .bdrv_co_preadv = write_threshold_co_preadv,
+ .bdrv_co_pwritev = write_threshold_co_pwritev,
+ .bdrv_co_pwrite_zeroes = write_threshold_co_pwrite_zeroes,
+ .bdrv_co_pdiscard = write_threshold_co_pdiscard,
+
+ .bdrv_getlength = write_threshold_getlength,
+ .bdrv_child_perm = bdrv_filter_default_perms,
+ .bdrv_co_get_block_status = write_threshold_co_get_block_status,
+ .bdrv_recurse_is_first_non_filter =
+ write_threshold_recurse_is_first_non_filter,
+
+ .is_filter = true,
+};
+
+static void bdrv_write_threshold_init(void)
+{
+ bdrv_register(&write_threshold);
+}
+
+block_init(bdrv_write_threshold_init);
diff --git a/include/block/write-threshold.h b/include/block/write-threshold.h
index 234d2193e0..5cf378564d 100644
--- a/include/block/write-threshold.h
+++ b/include/block/write-threshold.h
@@ -15,7 +15,7 @@
#include "qemu-common.h"
/*
- * bdrv_write_threshold_set:
+ * bdrv_write_threshold_set_legacy:
*
* Set the write threshold for block devices, in bytes.
* Notify when a write exceeds the threshold, meaning the device
@@ -24,22 +24,25 @@
*
* Use threshold_bytes == 0 to disable.
*/
-void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes);
+void bdrv_write_threshold_set_legacy(BlockDriverState *bs,
+ uint64_t threshold_bytes);
+
/*
- * bdrv_write_threshold_get
+ * bdrv_write_threshold_get_legacy
*
* Get the configured write threshold, in bytes.
* Zero means no threshold configured.
+ *
*/
-uint64_t bdrv_write_threshold_get(const BlockDriverState *bs);
+uint64_t bdrv_write_threshold_get_legacy(const BlockDriverState *bs);
/*
- * bdrv_write_threshold_is_set
+ * bdrv_write_threshold_is_set_legacy
*
* Tell if a write threshold is set for a given BDS.
*/
-bool bdrv_write_threshold_is_set(const BlockDriverState *bs);
+bool bdrv_write_threshold_is_set_legacy(const BlockDriverState *bs);
/*
* bdrv_write_threshold_exceeded
@@ -51,11 +54,10 @@ bool bdrv_write_threshold_is_set(const BlockDriverState
*bs);
* NOTE: here we assume the following holds for each request this code
* deals with:
*
- * assert((req->offset + req->bytes) <= UINT64_MAX)
+ * assert((offset + bytes) <= UINT64_MAX)
*
* Please not there is *not* an actual C assert().
*/
-uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs,
- const BdrvTrackedRequest *req);
-
+uint64_t bdrv_write_threshold_exceeded(uint64_t threshold, uint64_t offset,
+ uint64_t bytes);
#endif
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 12fd749a94..4d6ba1baef 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2232,7 +2232,8 @@
'host_device', 'http', 'https', 'iscsi', 'luks', 'nbd', 'nfs',
'null-aio', 'null-co', 'parallels', 'qcow', 'qcow2', 'qed',
'quorum', 'raw', 'rbd', 'replication', 'sheepdog', 'ssh',
- 'throttle', 'vdi', 'vhdx', 'vmdk', 'vpc', 'vvfat', 'vxhs' ] }
+ 'throttle', 'vdi', 'vhdx', 'vmdk', 'vpc', 'vvfat', 'vxhs',
+ 'write-threshold'] }
##
# @BlockdevOptionsFile:
@@ -3113,6 +3114,21 @@
'file' : 'BlockdevRef',
'*limits' : 'ThrottleLimits'
} }
+
+##
+# @BlockdevOptionsWriteThreshold:
+#
+# Driver specific block device options for the write-threshold driver
+#
+# @file: reference to or definition of the data source block device
+# @write-threshold: threshold in bytes
+# Since: 2.11
+##
+{ 'struct': 'BlockdevOptionsWriteThreshold',
+ 'data': { '*file' : 'BlockdevRef',
+ 'write-threshold' : 'int'
+ } }
+
##
# @BlockdevOptions:
#
@@ -3175,6 +3191,7 @@
'sheepdog': 'BlockdevOptionsSheepdog',
'ssh': 'BlockdevOptionsSsh',
'throttle': 'BlockdevOptionsThrottle',
+ 'write-threshold': 'BlockdevOptionsWriteThreshold',
'vdi': 'BlockdevOptionsGenericFormat',
'vhdx': 'BlockdevOptionsGenericFormat',
'vmdk': 'BlockdevOptionsGenericCOWFormat',
diff --git a/tests/test-write-threshold.c b/tests/test-write-threshold.c
index 97ca12f710..1c802d2de4 100644
--- a/tests/test-write-threshold.c
+++ b/tests/test-write-threshold.c
@@ -17,9 +17,9 @@ static void test_threshold_not_set_on_init(void)
BlockDriverState bs;
memset(&bs, 0, sizeof(bs));
- g_assert(!bdrv_write_threshold_is_set(&bs));
+ g_assert(!bdrv_write_threshold_is_set_legacy(&bs));
- res = bdrv_write_threshold_get(&bs);
+ res = bdrv_write_threshold_get_legacy(&bs);
g_assert_cmpint(res, ==, 0);
}
@@ -30,11 +30,11 @@ static void test_threshold_set_get(void)
BlockDriverState bs;
memset(&bs, 0, sizeof(bs));
- bdrv_write_threshold_set(&bs, threshold);
+ bdrv_write_threshold_set_legacy(&bs, threshold);
- g_assert(bdrv_write_threshold_is_set(&bs));
+ g_assert(bdrv_write_threshold_is_set_legacy(&bs));
- res = bdrv_write_threshold_get(&bs);
+ res = bdrv_write_threshold_get_legacy(&bs);
g_assert_cmpint(res, ==, threshold);
}
@@ -46,9 +46,9 @@ static void test_threshold_multi_set_get(void)
BlockDriverState bs;
memset(&bs, 0, sizeof(bs));
- bdrv_write_threshold_set(&bs, threshold1);
- bdrv_write_threshold_set(&bs, threshold2);
- res = bdrv_write_threshold_get(&bs);
+ bdrv_write_threshold_set_legacy(&bs, threshold1);
+ bdrv_write_threshold_set_legacy(&bs, threshold2);
+ res = bdrv_write_threshold_get_legacy(&bs);
g_assert_cmpint(res, ==, threshold2);
}
@@ -56,16 +56,10 @@ static void test_threshold_not_trigger(void)
{
uint64_t amount = 0;
uint64_t threshold = 4 * 1024 * 1024;
- BlockDriverState bs;
- BdrvTrackedRequest req;
+ uint64_t offset = 1024;
+ uint64_t bytes = 1024;
- memset(&bs, 0, sizeof(bs));
- memset(&req, 0, sizeof(req));
- req.offset = 1024;
- req.bytes = 1024;
-
- bdrv_write_threshold_set(&bs, threshold);
- amount = bdrv_write_threshold_exceeded(&bs, &req);
+ amount = bdrv_write_threshold_exceeded(threshold, offset, bytes);
g_assert_cmpuint(amount, ==, 0);
}
@@ -74,16 +68,10 @@ static void test_threshold_trigger(void)
{
uint64_t amount = 0;
uint64_t threshold = 4 * 1024 * 1024;
- BlockDriverState bs;
- BdrvTrackedRequest req;
+ uint64_t offset = (4 * 1024 * 1024) - 1024;
+ uint64_t bytes = 2 * 1024;
- memset(&bs, 0, sizeof(bs));
- memset(&req, 0, sizeof(req));
- req.offset = (4 * 1024 * 1024) - 1024;
- req.bytes = 2 * 1024;
-
- bdrv_write_threshold_set(&bs, threshold);
- amount = bdrv_write_threshold_exceeded(&bs, &req);
+ amount = bdrv_write_threshold_exceeded(threshold, offset, bytes);
g_assert_cmpuint(amount, >=, 1024);
}
--
2.11.0