Add support for taking and passing forward job creation flags. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Message-id: 20180906130225.5118-2-jsnow@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
525 lines
15 KiB
C
525 lines
15 KiB
C
/*
|
|
* Live block commit
|
|
*
|
|
* Copyright Red Hat, Inc. 2012
|
|
*
|
|
* Authors:
|
|
* Jeff Cody <jcody@redhat.com>
|
|
* Based on stream.c by Stefan Hajnoczi
|
|
*
|
|
* 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.
|
|
*
|
|
*/
|
|
|
|
#include "qemu/osdep.h"
|
|
#include "qemu/cutils.h"
|
|
#include "trace.h"
|
|
#include "block/block_int.h"
|
|
#include "block/blockjob_int.h"
|
|
#include "qapi/error.h"
|
|
#include "qapi/qmp/qerror.h"
|
|
#include "qemu/ratelimit.h"
|
|
#include "sysemu/block-backend.h"
|
|
|
|
enum {
|
|
/*
|
|
* Size of data buffer for populating the image file. This should be large
|
|
* enough to process multiple clusters in a single call, so that populating
|
|
* contiguous regions of the image is efficient.
|
|
*/
|
|
COMMIT_BUFFER_SIZE = 512 * 1024, /* in bytes */
|
|
};
|
|
|
|
typedef struct CommitBlockJob {
|
|
BlockJob common;
|
|
BlockDriverState *commit_top_bs;
|
|
BlockBackend *top;
|
|
BlockBackend *base;
|
|
BlockdevOnError on_error;
|
|
int base_flags;
|
|
char *backing_file_str;
|
|
} CommitBlockJob;
|
|
|
|
static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,
|
|
int64_t offset, uint64_t bytes,
|
|
void *buf)
|
|
{
|
|
int ret = 0;
|
|
QEMUIOVector qiov;
|
|
struct iovec iov = {
|
|
.iov_base = buf,
|
|
.iov_len = bytes,
|
|
};
|
|
|
|
assert(bytes < SIZE_MAX);
|
|
qemu_iovec_init_external(&qiov, &iov, 1);
|
|
|
|
ret = blk_co_preadv(bs, offset, qiov.size, &qiov, 0);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
ret = blk_co_pwritev(base, offset, qiov.size, &qiov, 0);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void commit_exit(Job *job)
|
|
{
|
|
CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
|
|
BlockJob *bjob = &s->common;
|
|
BlockDriverState *top = blk_bs(s->top);
|
|
BlockDriverState *base = blk_bs(s->base);
|
|
BlockDriverState *commit_top_bs = s->commit_top_bs;
|
|
bool remove_commit_top_bs = false;
|
|
|
|
/* Make sure commit_top_bs and top stay around until bdrv_replace_node() */
|
|
bdrv_ref(top);
|
|
bdrv_ref(commit_top_bs);
|
|
|
|
/* Remove base node parent that still uses BLK_PERM_WRITE/RESIZE before
|
|
* the normal backing chain can be restored. */
|
|
blk_unref(s->base);
|
|
|
|
if (!job_is_cancelled(job) && job->ret == 0) {
|
|
/* success */
|
|
job->ret = bdrv_drop_intermediate(s->commit_top_bs, base,
|
|
s->backing_file_str);
|
|
} else {
|
|
/* XXX Can (or should) we somehow keep 'consistent read' blocked even
|
|
* after the failed/cancelled commit job is gone? If we already wrote
|
|
* something to base, the intermediate images aren't valid any more. */
|
|
remove_commit_top_bs = true;
|
|
}
|
|
|
|
/* restore base open flags here if appropriate (e.g., change the base back
|
|
* to r/o). These reopens do not need to be atomic, since we won't abort
|
|
* even on failure here */
|
|
if (s->base_flags != bdrv_get_flags(base)) {
|
|
bdrv_reopen(base, s->base_flags, NULL);
|
|
}
|
|
g_free(s->backing_file_str);
|
|
blk_unref(s->top);
|
|
|
|
/* If there is more than one reference to the job (e.g. if called from
|
|
* job_finish_sync()), job_completed() won't free it and therefore the
|
|
* blockers on the intermediate nodes remain. This would cause
|
|
* bdrv_set_backing_hd() to fail. */
|
|
block_job_remove_all_bdrv(bjob);
|
|
|
|
/* If bdrv_drop_intermediate() didn't already do that, remove the commit
|
|
* filter driver from the backing chain. Do this as the final step so that
|
|
* the 'consistent read' permission can be granted. */
|
|
if (remove_commit_top_bs) {
|
|
bdrv_child_try_set_perm(commit_top_bs->backing, 0, BLK_PERM_ALL,
|
|
&error_abort);
|
|
bdrv_replace_node(commit_top_bs, backing_bs(commit_top_bs),
|
|
&error_abort);
|
|
}
|
|
|
|
bdrv_unref(commit_top_bs);
|
|
bdrv_unref(top);
|
|
}
|
|
|
|
static int coroutine_fn commit_run(Job *job, Error **errp)
|
|
{
|
|
CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
|
|
int64_t offset;
|
|
uint64_t delay_ns = 0;
|
|
int ret = 0;
|
|
int64_t n = 0; /* bytes */
|
|
void *buf = NULL;
|
|
int bytes_written = 0;
|
|
int64_t len, base_len;
|
|
|
|
ret = len = blk_getlength(s->top);
|
|
if (len < 0) {
|
|
goto out;
|
|
}
|
|
job_progress_set_remaining(&s->common.job, len);
|
|
|
|
ret = base_len = blk_getlength(s->base);
|
|
if (base_len < 0) {
|
|
goto out;
|
|
}
|
|
|
|
if (base_len < len) {
|
|
ret = blk_truncate(s->base, len, PREALLOC_MODE_OFF, NULL);
|
|
if (ret) {
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
buf = blk_blockalign(s->top, COMMIT_BUFFER_SIZE);
|
|
|
|
for (offset = 0; offset < len; offset += n) {
|
|
bool copy;
|
|
|
|
/* Note that even when no rate limit is applied we need to yield
|
|
* with no pending I/O here so that bdrv_drain_all() returns.
|
|
*/
|
|
job_sleep_ns(&s->common.job, delay_ns);
|
|
if (job_is_cancelled(&s->common.job)) {
|
|
break;
|
|
}
|
|
/* Copy if allocated above the base */
|
|
ret = bdrv_is_allocated_above(blk_bs(s->top), blk_bs(s->base),
|
|
offset, COMMIT_BUFFER_SIZE, &n);
|
|
copy = (ret == 1);
|
|
trace_commit_one_iteration(s, offset, n, ret);
|
|
if (copy) {
|
|
ret = commit_populate(s->top, s->base, offset, n, buf);
|
|
bytes_written += n;
|
|
}
|
|
if (ret < 0) {
|
|
BlockErrorAction action =
|
|
block_job_error_action(&s->common, false, s->on_error, -ret);
|
|
if (action == BLOCK_ERROR_ACTION_REPORT) {
|
|
goto out;
|
|
} else {
|
|
n = 0;
|
|
continue;
|
|
}
|
|
}
|
|
/* Publish progress */
|
|
job_progress_update(&s->common.job, n);
|
|
|
|
if (copy) {
|
|
delay_ns = block_job_ratelimit_get_delay(&s->common, n);
|
|
} else {
|
|
delay_ns = 0;
|
|
}
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
out:
|
|
qemu_vfree(buf);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const BlockJobDriver commit_job_driver = {
|
|
.job_driver = {
|
|
.instance_size = sizeof(CommitBlockJob),
|
|
.job_type = JOB_TYPE_COMMIT,
|
|
.free = block_job_free,
|
|
.user_resume = block_job_user_resume,
|
|
.drain = block_job_drain,
|
|
.run = commit_run,
|
|
.exit = commit_exit,
|
|
},
|
|
};
|
|
|
|
static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs,
|
|
uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
|
|
{
|
|
return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
|
|
}
|
|
|
|
static void bdrv_commit_top_refresh_filename(BlockDriverState *bs, QDict *opts)
|
|
{
|
|
bdrv_refresh_filename(bs->backing->bs);
|
|
pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
|
|
bs->backing->bs->filename);
|
|
}
|
|
|
|
static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
|
|
const BdrvChildRole *role,
|
|
BlockReopenQueue *reopen_queue,
|
|
uint64_t perm, uint64_t shared,
|
|
uint64_t *nperm, uint64_t *nshared)
|
|
{
|
|
*nperm = 0;
|
|
*nshared = BLK_PERM_ALL;
|
|
}
|
|
|
|
/* Dummy node that provides consistent read to its users without requiring it
|
|
* from its backing file and that allows writes on the backing file chain. */
|
|
static BlockDriver bdrv_commit_top = {
|
|
.format_name = "commit_top",
|
|
.bdrv_co_preadv = bdrv_commit_top_preadv,
|
|
.bdrv_co_block_status = bdrv_co_block_status_from_backing,
|
|
.bdrv_refresh_filename = bdrv_commit_top_refresh_filename,
|
|
.bdrv_child_perm = bdrv_commit_top_child_perm,
|
|
};
|
|
|
|
void commit_start(const char *job_id, BlockDriverState *bs,
|
|
BlockDriverState *base, BlockDriverState *top,
|
|
int creation_flags, int64_t speed,
|
|
BlockdevOnError on_error, const char *backing_file_str,
|
|
const char *filter_node_name, Error **errp)
|
|
{
|
|
CommitBlockJob *s;
|
|
int orig_base_flags;
|
|
BlockDriverState *iter;
|
|
BlockDriverState *commit_top_bs = NULL;
|
|
Error *local_err = NULL;
|
|
int ret;
|
|
|
|
assert(top != bs);
|
|
if (top == base) {
|
|
error_setg(errp, "Invalid files for merge: top and base are the same");
|
|
return;
|
|
}
|
|
|
|
s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL,
|
|
speed, creation_flags, NULL, NULL, errp);
|
|
if (!s) {
|
|
return;
|
|
}
|
|
|
|
/* convert base to r/w, if necessary */
|
|
orig_base_flags = bdrv_get_flags(base);
|
|
if (!(orig_base_flags & BDRV_O_RDWR)) {
|
|
bdrv_reopen(base, orig_base_flags | BDRV_O_RDWR, &local_err);
|
|
if (local_err != NULL) {
|
|
error_propagate(errp, local_err);
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
/* Insert commit_top block node above top, so we can block consistent read
|
|
* on the backing chain below it */
|
|
commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, filter_node_name, 0,
|
|
errp);
|
|
if (commit_top_bs == NULL) {
|
|
goto fail;
|
|
}
|
|
if (!filter_node_name) {
|
|
commit_top_bs->implicit = true;
|
|
}
|
|
commit_top_bs->total_sectors = top->total_sectors;
|
|
bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top));
|
|
|
|
bdrv_set_backing_hd(commit_top_bs, top, &local_err);
|
|
if (local_err) {
|
|
bdrv_unref(commit_top_bs);
|
|
commit_top_bs = NULL;
|
|
error_propagate(errp, local_err);
|
|
goto fail;
|
|
}
|
|
bdrv_replace_node(top, commit_top_bs, &local_err);
|
|
if (local_err) {
|
|
bdrv_unref(commit_top_bs);
|
|
commit_top_bs = NULL;
|
|
error_propagate(errp, local_err);
|
|
goto fail;
|
|
}
|
|
|
|
s->commit_top_bs = commit_top_bs;
|
|
bdrv_unref(commit_top_bs);
|
|
|
|
/* Block all nodes between top and base, because they will
|
|
* disappear from the chain after this operation. */
|
|
assert(bdrv_chain_contains(top, base));
|
|
for (iter = top; iter != base; iter = backing_bs(iter)) {
|
|
/* XXX BLK_PERM_WRITE needs to be allowed so we don't block ourselves
|
|
* at s->base (if writes are blocked for a node, they are also blocked
|
|
* for its backing file). The other options would be a second filter
|
|
* driver above s->base. */
|
|
ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
|
|
BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
|
|
errp);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
s->base = blk_new(BLK_PERM_CONSISTENT_READ
|
|
| BLK_PERM_WRITE
|
|
| BLK_PERM_RESIZE,
|
|
BLK_PERM_CONSISTENT_READ
|
|
| BLK_PERM_GRAPH_MOD
|
|
| BLK_PERM_WRITE_UNCHANGED);
|
|
ret = blk_insert_bs(s->base, base, errp);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
/* Required permissions are already taken with block_job_add_bdrv() */
|
|
s->top = blk_new(0, BLK_PERM_ALL);
|
|
ret = blk_insert_bs(s->top, top, errp);
|
|
if (ret < 0) {
|
|
goto fail;
|
|
}
|
|
|
|
s->base_flags = orig_base_flags;
|
|
s->backing_file_str = g_strdup(backing_file_str);
|
|
s->on_error = on_error;
|
|
|
|
trace_commit_start(bs, base, top, s);
|
|
job_start(&s->common.job);
|
|
return;
|
|
|
|
fail:
|
|
if (s->base) {
|
|
blk_unref(s->base);
|
|
}
|
|
if (s->top) {
|
|
blk_unref(s->top);
|
|
}
|
|
if (commit_top_bs) {
|
|
bdrv_replace_node(commit_top_bs, top, &error_abort);
|
|
}
|
|
job_early_fail(&s->common.job);
|
|
}
|
|
|
|
|
|
#define COMMIT_BUF_SIZE (2048 * BDRV_SECTOR_SIZE)
|
|
|
|
/* commit COW file into the raw image */
|
|
int bdrv_commit(BlockDriverState *bs)
|
|
{
|
|
BlockBackend *src, *backing;
|
|
BlockDriverState *backing_file_bs = NULL;
|
|
BlockDriverState *commit_top_bs = NULL;
|
|
BlockDriver *drv = bs->drv;
|
|
int64_t offset, length, backing_length;
|
|
int ro, open_flags;
|
|
int64_t n;
|
|
int ret = 0;
|
|
uint8_t *buf = NULL;
|
|
Error *local_err = NULL;
|
|
|
|
if (!drv)
|
|
return -ENOMEDIUM;
|
|
|
|
if (!bs->backing) {
|
|
return -ENOTSUP;
|
|
}
|
|
|
|
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
|
|
bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {
|
|
return -EBUSY;
|
|
}
|
|
|
|
ro = bs->backing->bs->read_only;
|
|
open_flags = bs->backing->bs->open_flags;
|
|
|
|
if (ro) {
|
|
if (bdrv_reopen(bs->backing->bs, open_flags | BDRV_O_RDWR, NULL)) {
|
|
return -EACCES;
|
|
}
|
|
}
|
|
|
|
src = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
|
|
backing = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
|
|
|
|
ret = blk_insert_bs(src, bs, &local_err);
|
|
if (ret < 0) {
|
|
error_report_err(local_err);
|
|
goto ro_cleanup;
|
|
}
|
|
|
|
/* Insert commit_top block node above backing, so we can write to it */
|
|
backing_file_bs = backing_bs(bs);
|
|
|
|
commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR,
|
|
&local_err);
|
|
if (commit_top_bs == NULL) {
|
|
error_report_err(local_err);
|
|
goto ro_cleanup;
|
|
}
|
|
bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(backing_file_bs));
|
|
|
|
bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort);
|
|
bdrv_set_backing_hd(bs, commit_top_bs, &error_abort);
|
|
|
|
ret = blk_insert_bs(backing, backing_file_bs, &local_err);
|
|
if (ret < 0) {
|
|
error_report_err(local_err);
|
|
goto ro_cleanup;
|
|
}
|
|
|
|
length = blk_getlength(src);
|
|
if (length < 0) {
|
|
ret = length;
|
|
goto ro_cleanup;
|
|
}
|
|
|
|
backing_length = blk_getlength(backing);
|
|
if (backing_length < 0) {
|
|
ret = backing_length;
|
|
goto ro_cleanup;
|
|
}
|
|
|
|
/* If our top snapshot is larger than the backing file image,
|
|
* grow the backing file image if possible. If not possible,
|
|
* we must return an error */
|
|
if (length > backing_length) {
|
|
ret = blk_truncate(backing, length, PREALLOC_MODE_OFF, &local_err);
|
|
if (ret < 0) {
|
|
error_report_err(local_err);
|
|
goto ro_cleanup;
|
|
}
|
|
}
|
|
|
|
/* blk_try_blockalign() for src will choose an alignment that works for
|
|
* backing as well, so no need to compare the alignment manually. */
|
|
buf = blk_try_blockalign(src, COMMIT_BUF_SIZE);
|
|
if (buf == NULL) {
|
|
ret = -ENOMEM;
|
|
goto ro_cleanup;
|
|
}
|
|
|
|
for (offset = 0; offset < length; offset += n) {
|
|
ret = bdrv_is_allocated(bs, offset, COMMIT_BUF_SIZE, &n);
|
|
if (ret < 0) {
|
|
goto ro_cleanup;
|
|
}
|
|
if (ret) {
|
|
ret = blk_pread(src, offset, buf, n);
|
|
if (ret < 0) {
|
|
goto ro_cleanup;
|
|
}
|
|
|
|
ret = blk_pwrite(backing, offset, buf, n, 0);
|
|
if (ret < 0) {
|
|
goto ro_cleanup;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (drv->bdrv_make_empty) {
|
|
ret = drv->bdrv_make_empty(bs);
|
|
if (ret < 0) {
|
|
goto ro_cleanup;
|
|
}
|
|
blk_flush(src);
|
|
}
|
|
|
|
/*
|
|
* Make sure all data we wrote to the backing device is actually
|
|
* stable on disk.
|
|
*/
|
|
blk_flush(backing);
|
|
|
|
ret = 0;
|
|
ro_cleanup:
|
|
qemu_vfree(buf);
|
|
|
|
blk_unref(backing);
|
|
if (backing_file_bs) {
|
|
bdrv_set_backing_hd(bs, backing_file_bs, &error_abort);
|
|
}
|
|
bdrv_unref(commit_top_bs);
|
|
blk_unref(src);
|
|
|
|
if (ro) {
|
|
/* ignoring error return here */
|
|
bdrv_reopen(bs->backing->bs, open_flags & ~BDRV_O_RDWR, NULL);
|
|
}
|
|
|
|
return ret;
|
|
}
|