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Block layer patches:

Browse Source 
- qcow2: Skip copy-on-write when allocating a zero cluster
 - qemu-img: add support for rate limit in qemu-img convert/commit
 - Fix deadlock when deleting a block node during drain_all
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Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- qcow2: Skip copy-on-write when allocating a zero cluster
- qemu-img: add support for rate limit in qemu-img convert/commit
- Fix deadlock when deleting a block node during drain_all

# gpg: Signature made Tue 27 Oct 2020 15:14:07 GMT
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  block: End quiescent sections when a BDS is deleted
  qcow2: Skip copy-on-write when allocating a zero cluster
  qcow2: Report BDRV_BLOCK_ZERO more accurately in bdrv_co_block_status()
  qemu-img: add support for rate limit in qemu-img convert
  qemu-img: add support for rate limit in qemu-img commit

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Maydell 2020-10-30 14:36:52 +00:00
commit c99fa56b95
8 changed files with 128 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
block.c
View File

@ -4458,6 +4458,15 @@ static void bdrv_close(BlockDriverState *bs)
}
QLIST_INIT(&bs->aio_notifiers);
bdrv_drained_end(bs);
/*
* If we're still inside some bdrv_drain_all_begin()/end() sections, end
* them now since this BDS won't exist anymore when bdrv_drain_all_end()
* gets called.
*/
if (bs->quiesce_counter) {
bdrv_drain_all_end_quiesce(bs);
}
}
void bdrv_close_all(void)

48
block/io.c
View File

@ -633,6 +633,19 @@ void bdrv_drain_all_begin(void)
}
}
void bdrv_drain_all_end_quiesce(BlockDriverState *bs)
{
int drained_end_counter = 0;
g_assert(bs->quiesce_counter > 0);
g_assert(!bs->refcnt);
while (bs->quiesce_counter) {
bdrv_do_drained_end(bs, false, NULL, true, &drained_end_counter);
}
BDRV_POLL_WHILE(bs, qatomic_read(&drained_end_counter) > 0);
}
void bdrv_drain_all_end(void)
{
BlockDriverState *bs = NULL;
@ -2282,17 +2295,17 @@ static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs,
if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) {
ret |= BDRV_BLOCK_ALLOCATED;
} else if (want_zero && bs->drv->supports_backing) {
} else if (bs->drv->supports_backing) {
BlockDriverState *cow_bs = bdrv_cow_bs(bs);
if (cow_bs) {
if (!cow_bs) {
ret |= BDRV_BLOCK_ZERO;
} else if (want_zero) {
int64_t size2 = bdrv_getlength(cow_bs);
if (size2 >= 0 && offset >= size2) {
ret |= BDRV_BLOCK_ZERO;
}
} else {
ret |= BDRV_BLOCK_ZERO;
}
}
@ -2447,6 +2460,33 @@ int bdrv_block_status(BlockDriverState *bs, int64_t offset, int64_t bytes,
offset, bytes, pnum, map, file);
}
/*
* Check @bs (and its backing chain) to see if the range defined
* by @offset and @bytes is known to read as zeroes.
* Return 1 if that is the case, 0 otherwise and -errno on error.
* This test is meant to be fast rather than accurate so returning 0
* does not guarantee non-zero data.
*/
int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset,
int64_t bytes)
{
int ret;
int64_t pnum = bytes;
if (!bytes) {
return 1;
}
ret = bdrv_common_block_status_above(bs, NULL, false, false, offset,
bytes, &pnum, NULL, NULL);
if (ret < 0) {
return ret;
}
return (pnum == bytes) && (ret & BDRV_BLOCK_ZERO);
}
int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t offset,
int64_t bytes, int64_t *pnum)
{

35
block/qcow2.c
View File

@ -2387,26 +2387,26 @@ static bool merge_cow(uint64_t offset, unsigned bytes,
return false;
}
static bool is_unallocated(BlockDriverState *bs, int64_t offset, int64_t bytes)
{
int64_t nr;
return !bytes ||
(!bdrv_is_allocated_above(bs, NULL, false, offset, bytes, &nr) &&
nr == bytes);
}
static bool is_zero_cow(BlockDriverState *bs, QCowL2Meta *m)
/*
* Return 1 if the COW regions read as zeroes, 0 if not, < 0 on error.
* Note that returning 0 does not guarantee non-zero data.
*/
static int is_zero_cow(BlockDriverState *bs, QCowL2Meta *m)
{
/*
* This check is designed for optimization shortcut so it must be
* efficient.
* Instead of is_zero(), use is_unallocated() as it is faster (but not
* as accurate and can result in false negatives).
* Instead of is_zero(), use bdrv_co_is_zero_fast() as it is
* faster (but not as accurate and can result in false negatives).
*/
return is_unallocated(bs, m->offset + m->cow_start.offset,
m->cow_start.nb_bytes) &&
is_unallocated(bs, m->offset + m->cow_end.offset,
m->cow_end.nb_bytes);
int ret = bdrv_co_is_zero_fast(bs, m->offset + m->cow_start.offset,
m->cow_start.nb_bytes);
if (ret <= 0) {
return ret;
}
return bdrv_co_is_zero_fast(bs, m->offset + m->cow_end.offset,
m->cow_end.nb_bytes);
}
static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta)
@ -2432,7 +2432,10 @@ static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta)
continue;
}
if (!is_zero_cow(bs, m)) {
ret = is_zero_cow(bs, m);
if (ret < 0) {
return ret;
} else if (ret == 0) {
continue;
}

10
docs/tools/qemu-img.rst
View File

@ -188,6 +188,10 @@ Parameters to convert subcommand:
allocated target image depending on the host support for getting allocation
information.
.. option:: -r
Rate limit for the convert process
.. option:: --salvage
Try to ignore I/O errors when reading. Unless in quiet mode (``-q``), errors
@ -349,7 +353,7 @@ Command description:
state after (the attempt at) repairing it. That is, a successful ``-r all``
will yield the exit code 0, independently of the image state before.
.. option:: commit [--object OBJECTDEF] [--image-opts] [-q] [-f FMT] [-t CACHE] [-b BASE] [-d] [-p] FILENAME
.. option:: commit [--object OBJECTDEF] [--image-opts] [-q] [-f FMT] [-t CACHE] [-b BASE] [-r RATE_LIMIT] [-d] [-p] FILENAME
Commit the changes recorded in *FILENAME* in its base image or backing file.
If the backing file is smaller than the snapshot, then the backing file will be
@ -371,6 +375,8 @@ Command description:
garbage data when read. For this reason, ``-b`` implies ``-d`` (so that
the top image stays valid).
The rate limit for the commit process is specified by ``-r``.
.. option:: compare [--object OBJECTDEF] [--image-opts] [-f FMT] [-F FMT] [-T SRC_CACHE] [-p] [-q] [-s] [-U] FILENAME1 FILENAME2
Check if two images have the same content. You can compare images with
@ -408,7 +414,7 @@ Command description:
4
Error on reading data
.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-r RATE_LIMIT] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
Convert the disk image *FILENAME* or a snapshot *SNAPSHOT_PARAM*
to disk image *OUTPUT_FILENAME* using format *OUTPUT_FMT*. It can

8
include/block/block.h
View File

@ -508,6 +508,8 @@ int bdrv_is_allocated(BlockDriverState *bs, int64_t offset, int64_t bytes,
int bdrv_is_allocated_above(BlockDriverState *top, BlockDriverState *base,
bool include_base, int64_t offset, int64_t bytes,
int64_t *pnum);
int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset,
int64_t bytes);
bool bdrv_is_read_only(BlockDriverState *bs);
int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only,
@ -779,6 +781,12 @@ void bdrv_drained_end(BlockDriverState *bs);
*/
void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);
/**
* End all quiescent sections started by bdrv_drain_all_begin(). This is
* only needed when deleting a BDS before bdrv_drain_all_end() is called.
*/
void bdrv_drain_all_end_quiesce(BlockDriverState *bs);
/**
* End a quiescent section started by bdrv_subtree_drained_begin().
*/

8
qemu-img-cmds.hx
View File

@ -34,9 +34,9 @@ SRST
ERST
DEF("commit", img_commit,
"commit [--object objectdef] [--image-opts] [-q] [-f fmt] [-t cache] [-b base] [-d] [-p] filename")
"commit [--object objectdef] [--image-opts] [-q] [-f fmt] [-t cache] [-b base] [-r rate_limit] [-d] [-p] filename")
SRST
.. option:: commit [--object OBJECTDEF] [--image-opts] [-q] [-f FMT] [-t CACHE] [-b BASE] [-d] [-p] FILENAME
.. option:: commit [--object OBJECTDEF] [--image-opts] [-q] [-f FMT] [-t CACHE] [-b BASE] [-r RATE_LIMIT] [-d] [-p] FILENAME
ERST
DEF("compare", img_compare,
@ -46,9 +46,9 @@ SRST
ERST
DEF("convert", img_convert,
"convert [--object objectdef] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-T src_cache] [-O output_fmt] [-B backing_file] [-o options] [-l snapshot_param] [-S sparse_size] [-m num_coroutines] [-W] [--salvage] filename [filename2 [...]] output_filename")
"convert [--object objectdef] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-T src_cache] [-O output_fmt] [-B backing_file] [-o options] [-l snapshot_param] [-S sparse_size] [-r rate_limit] [-m num_coroutines] [-W] [--salvage] filename [filename2 [...]] output_filename")
SRST
.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] [--salvage] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-r RATE_LIMIT] [-m NUM_COROUTINES] [-W] [--salvage] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
ERST
DEF("create", img_create,

38
qemu-img.c
View File

@ -50,6 +50,8 @@
#include "block/qapi.h"
#include "crypto/init.h"
#include "trace/control.h"
#include "qemu/throttle.h"
#include "block/throttle-groups.h"
#define QEMU_IMG_VERSION "qemu-img version " QEMU_FULL_VERSION \
"\n" QEMU_COPYRIGHT "\n"
@ -980,6 +982,7 @@ static int img_commit(int argc, char **argv)
CommonBlockJobCBInfo cbi;
bool image_opts = false;
AioContext *aio_context;
int64_t rate_limit = 0;
fmt = NULL;
cache = BDRV_DEFAULT_CACHE;
@ -991,7 +994,7 @@ static int img_commit(int argc, char **argv)
{"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
{0, 0, 0, 0}
};
c = getopt_long(argc, argv, ":f:ht:b:dpq",
c = getopt_long(argc, argv, ":f:ht:b:dpqr:",
long_options, NULL);
if (c == -1) {
break;
@ -1026,6 +1029,12 @@ static int img_commit(int argc, char **argv)
case 'q':
quiet = true;
break;
case 'r':
rate_limit = cvtnum("rate limit", optarg);
if (rate_limit < 0) {
return 1;
}
break;
case OPTION_OBJECT: {
QemuOpts *opts;
opts = qemu_opts_parse_noisily(&qemu_object_opts,
@ -1099,7 +1108,7 @@ static int img_commit(int argc, char **argv)
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
commit_active_start("commit", bs, base_bs, JOB_DEFAULT, 0,
commit_active_start("commit", bs, base_bs, JOB_DEFAULT, rate_limit,
BLOCKDEV_ON_ERROR_REPORT, NULL, common_block_job_cb,
&cbi, false, &local_err);
aio_context_release(aio_context);
@ -1662,6 +1671,7 @@ enum ImgConvertBlockStatus {
};
#define MAX_COROUTINES 16
#define CONVERT_THROTTLE_GROUP "img_convert"
typedef struct ImgConvertState {
BlockBackend **src;
@ -2177,6 +2187,17 @@ static int convert_copy_bitmaps(BlockDriverState *src, BlockDriverState *dst)
#define MAX_BUF_SECTORS 32768
static void set_rate_limit(BlockBackend *blk, int64_t rate_limit)
{
ThrottleConfig cfg;
throttle_config_init(&cfg);
cfg.buckets[THROTTLE_BPS_WRITE].avg = rate_limit;
blk_io_limits_enable(blk, CONVERT_THROTTLE_GROUP);
blk_set_io_limits(blk, &cfg);
}
static int img_convert(int argc, char **argv)
{
int c, bs_i, flags, src_flags = 0;
@ -2197,6 +2218,7 @@ static int img_convert(int argc, char **argv)
bool force_share = false;
bool explict_min_sparse = false;
bool bitmaps = false;
int64_t rate_limit = 0;
ImgConvertState s = (ImgConvertState) {
/* Need at least 4k of zeros for sparse detection */
@ -2219,7 +2241,7 @@ static int img_convert(int argc, char **argv)
{"bitmaps", no_argument, 0, OPTION_BITMAPS},
{0, 0, 0, 0}
};
c = getopt_long(argc, argv, ":hf:O:B:Cco:l:S:pt:T:qnm:WU",
c = getopt_long(argc, argv, ":hf:O:B:Cco:l:S:pt:T:qnm:WUr:",
long_options, NULL);
if (c == -1) {
break;
@ -2316,6 +2338,12 @@ static int img_convert(int argc, char **argv)
case 'U':
force_share = true;
break;
case 'r':
rate_limit = cvtnum("rate limit", optarg);
if (rate_limit < 0) {
goto fail_getopt;
}
break;
case OPTION_OBJECT: {
QemuOpts *object_opts;
object_opts = qemu_opts_parse_noisily(&qemu_object_opts,
@ -2705,6 +2733,10 @@ static int img_convert(int argc, char **argv)
s.cluster_sectors = bdi.cluster_size / BDRV_SECTOR_SIZE;
}
if (rate_limit) {
set_rate_limit(s.target, rate_limit);
}
ret = convert_do_copy(&s);
/* Now copy the bitmaps */

1
tests/test-bdrv-drain.c
View File

@ -594,6 +594,7 @@ static void test_graph_change_drain_all(void)
g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
g_assert_cmpint(b_s->drain_count, ==, 0);
g_assert_cmpint(qemu_get_aio_context()->external_disable_cnt, ==, 0);
bdrv_unref(bs_b);
blk_unref(blk_b);