*/
#include "qemu/osdep.h"
+#include "qemu/cutils.h"
#include "trace.h"
#include "block/blockjob_int.h"
#include "block/block_int.h"
BlockJob common;
RateLimit limit;
BlockBackend *target;
+ BlockDriverState *mirror_top_bs;
+ BlockDriverState *source;
BlockDriverState *base;
+
/* The name of the graph node to replace */
char *replaces;
/* The BDS to replace */
static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
{
- BlockDriverState *source = blk_bs(s->common.blk);
+ BlockDriverState *source = s->source;
int64_t sector_num, first_chunk;
uint64_t delay_ns = 0;
/* At least the first dirty chunk is mirrored in one iteration. */
nb_chunks * sectors_per_chunk);
bitmap_set(s->in_flight_bitmap, sector_num / sectors_per_chunk, nb_chunks);
while (nb_chunks > 0 && sector_num < end) {
- int ret;
+ int64_t ret;
int io_sectors, io_sectors_acct;
BlockDriverState *file;
enum MirrorMethod {
MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
MirrorExitData *data = opaque;
AioContext *replace_aio_context = NULL;
- BlockDriverState *src = blk_bs(s->common.blk);
+ BlockDriverState *src = s->source;
BlockDriverState *target_bs = blk_bs(s->target);
+ BlockDriverState *mirror_top_bs = s->mirror_top_bs;
+ Error *local_err = NULL;
/* Make sure that the source BDS doesn't go away before we called
* block_job_completed(). */
bdrv_ref(src);
+ bdrv_ref(mirror_top_bs);
+ bdrv_ref(target_bs);
+
+ /* Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
+ * inserting target_bs at s->to_replace, where we might not be able to get
+ * these permissions. */
+ blk_unref(s->target);
+ s->target = NULL;
+
+ /* We don't access the source any more. Dropping any WRITE/RESIZE is
+ * required before it could become a backing file of target_bs. */
+ bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL,
+ &error_abort);
+ if (s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) {
+ BlockDriverState *backing = s->is_none_mode ? src : s->base;
+ if (backing_bs(target_bs) != backing) {
+ bdrv_set_backing_hd(target_bs, backing, &local_err);
+ if (local_err) {
+ error_report_err(local_err);
+ data->ret = -EPERM;
+ }
+ }
+ }
if (s->to_replace) {
replace_aio_context = bdrv_get_aio_context(s->to_replace);
/* The mirror job has no requests in flight any more, but we need to
* drain potential other users of the BDS before changing the graph. */
bdrv_drained_begin(target_bs);
- bdrv_replace_in_backing_chain(to_replace, target_bs);
+ bdrv_replace_node(to_replace, target_bs, &local_err);
bdrv_drained_end(target_bs);
-
- /* We just changed the BDS the job BB refers to */
- blk_remove_bs(job->blk);
- blk_insert_bs(job->blk, src);
+ if (local_err) {
+ error_report_err(local_err);
+ data->ret = -EPERM;
+ }
}
if (s->to_replace) {
bdrv_op_unblock_all(s->to_replace, s->replace_blocker);
aio_context_release(replace_aio_context);
}
g_free(s->replaces);
- blk_unref(s->target);
- s->target = NULL;
+ bdrv_unref(target_bs);
+
+ /* Remove the mirror filter driver from the graph. Before this, get rid of
+ * the blockers on the intermediate nodes so that the resulting state is
+ * valid. Also give up permissions on mirror_top_bs->backing, which might
+ * block the removal. */
+ block_job_remove_all_bdrv(job);
+ bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL,
+ &error_abort);
+ bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort);
+
+ /* We just changed the BDS the job BB refers to (with either or both of the
+ * bdrv_replace_node() calls), so switch the BB back so the cleanup does
+ * the right thing. We don't need any permissions any more now. */
+ blk_remove_bs(job->blk);
+ blk_set_perm(job->blk, 0, BLK_PERM_ALL, &error_abort);
+ blk_insert_bs(job->blk, mirror_top_bs, &error_abort);
+
block_job_completed(&s->common, data->ret);
+
g_free(data);
bdrv_drained_end(src);
+ bdrv_unref(mirror_top_bs);
bdrv_unref(src);
}
{
int64_t sector_num, end;
BlockDriverState *base = s->base;
- BlockDriverState *bs = blk_bs(s->common.blk);
+ BlockDriverState *bs = s->source;
BlockDriverState *target_bs = blk_bs(s->target);
int ret, n;
}
if (s->in_flight >= MAX_IN_FLIGHT) {
- trace_mirror_yield(s, s->in_flight, s->buf_free_count, -1);
+ trace_mirror_yield(s, UINT64_MAX, s->buf_free_count,
+ s->in_flight);
mirror_wait_for_io(s);
continue;
}
{
MirrorBlockJob *s = opaque;
MirrorExitData *data;
- BlockDriverState *bs = blk_bs(s->common.blk);
+ BlockDriverState *bs = s->source;
BlockDriverState *target_bs = blk_bs(s->target);
bool need_drain = true;
int64_t length;
if (s->bdev_length < 0) {
ret = s->bdev_length;
goto immediate_exit;
- } else if (s->bdev_length == 0) {
+ }
+
+ /* Active commit must resize the base image if its size differs from the
+ * active layer. */
+ if (s->base == blk_bs(s->target)) {
+ int64_t base_length;
+
+ base_length = blk_getlength(s->target);
+ if (base_length < 0) {
+ ret = base_length;
+ goto immediate_exit;
+ }
+
+ if (s->bdev_length > base_length) {
+ ret = blk_truncate(s->target, s->bdev_length);
+ if (ret < 0) {
+ goto immediate_exit;
+ }
+ }
+ }
+
+ if (s->bdev_length == 0) {
/* Report BLOCK_JOB_READY and wait for complete. */
block_job_event_ready(&s->common);
s->synced = true;
s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 ||
(cnt == 0 && s->in_flight > 0)) {
- trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt);
+ trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight);
mirror_wait_for_io(s);
continue;
} else if (cnt != 0) {
static void mirror_complete(BlockJob *job, Error **errp)
{
MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
- BlockDriverState *src, *target;
+ BlockDriverState *target;
- src = blk_bs(job->blk);
target = blk_bs(s->target);
if (!s->synced) {
replace_aio_context = bdrv_get_aio_context(s->to_replace);
aio_context_acquire(replace_aio_context);
+ /* TODO Translate this into permission system. Current definition of
+ * GRAPH_MOD would require to request it for the parents; they might
+ * not even be BlockDriverStates, however, so a BdrvChild can't address
+ * them. May need redefinition of GRAPH_MOD. */
error_setg(&s->replace_blocker,
"block device is in use by block-job-complete");
bdrv_op_block_all(s->to_replace, s->replace_blocker);
aio_context_release(replace_aio_context);
}
- if (s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) {
- BlockDriverState *backing = s->is_none_mode ? src : s->base;
- if (backing_bs(target) != backing) {
- bdrv_set_backing_hd(target, backing);
- }
- }
-
s->should_complete = true;
block_job_enter(&s->common);
}
.drain = mirror_drain,
};
+static int coroutine_fn bdrv_mirror_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 int coroutine_fn bdrv_mirror_top_pwritev(BlockDriverState *bs,
+ uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)
+{
+ return bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags);
+}
+
+static int coroutine_fn bdrv_mirror_top_flush(BlockDriverState *bs)
+{
+ return bdrv_co_flush(bs->backing->bs);
+}
+
+static int64_t coroutine_fn bdrv_mirror_top_get_block_status(
+ BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum,
+ BlockDriverState **file)
+{
+ *pnum = nb_sectors;
+ *file = bs->backing->bs;
+ return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
+ (sector_num << BDRV_SECTOR_BITS);
+}
+
+static int coroutine_fn bdrv_mirror_top_pwrite_zeroes(BlockDriverState *bs,
+ int64_t offset, int count, BdrvRequestFlags flags)
+{
+ return bdrv_co_pwrite_zeroes(bs->backing, offset, count, flags);
+}
+
+static int coroutine_fn bdrv_mirror_top_pdiscard(BlockDriverState *bs,
+ int64_t offset, int count)
+{
+ return bdrv_co_pdiscard(bs->backing->bs, offset, count);
+}
+
+static void bdrv_mirror_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_mirror_top_close(BlockDriverState *bs)
+{
+}
+
+static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c,
+ const BdrvChildRole *role,
+ uint64_t perm, uint64_t shared,
+ uint64_t *nperm, uint64_t *nshared)
+{
+ /* Must be able to forward guest writes to the real image */
+ *nperm = 0;
+ if (perm & BLK_PERM_WRITE) {
+ *nperm |= BLK_PERM_WRITE;
+ }
+
+ *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_mirror_top = {
+ .format_name = "mirror_top",
+ .bdrv_co_preadv = bdrv_mirror_top_preadv,
+ .bdrv_co_pwritev = bdrv_mirror_top_pwritev,
+ .bdrv_co_pwrite_zeroes = bdrv_mirror_top_pwrite_zeroes,
+ .bdrv_co_pdiscard = bdrv_mirror_top_pdiscard,
+ .bdrv_co_flush = bdrv_mirror_top_flush,
+ .bdrv_co_get_block_status = bdrv_mirror_top_get_block_status,
+ .bdrv_refresh_filename = bdrv_mirror_top_refresh_filename,
+ .bdrv_close = bdrv_mirror_top_close,
+ .bdrv_child_perm = bdrv_mirror_top_child_perm,
+};
+
static void mirror_start_job(const char *job_id, BlockDriverState *bs,
int creation_flags, BlockDriverState *target,
const char *replaces, int64_t speed,
void *opaque, Error **errp,
const BlockJobDriver *driver,
bool is_none_mode, BlockDriverState *base,
- bool auto_complete)
+ bool auto_complete, const char *filter_node_name)
{
MirrorBlockJob *s;
+ BlockDriverState *mirror_top_bs;
+ bool target_graph_mod;
+ bool target_is_backing;
+ Error *local_err = NULL;
+ int ret;
if (granularity == 0) {
granularity = bdrv_get_default_bitmap_granularity(target);
buf_size = DEFAULT_MIRROR_BUF_SIZE;
}
- s = block_job_create(job_id, driver, bs, speed, creation_flags,
- cb, opaque, errp);
- if (!s) {
+ /* In the case of active commit, add dummy driver to provide consistent
+ * reads on the top, while disabling it in the intermediate nodes, and make
+ * the backing chain writable. */
+ mirror_top_bs = bdrv_new_open_driver(&bdrv_mirror_top, filter_node_name,
+ BDRV_O_RDWR, errp);
+ if (mirror_top_bs == NULL) {
+ return;
+ }
+ mirror_top_bs->total_sectors = bs->total_sectors;
+
+ /* bdrv_append takes ownership of the mirror_top_bs reference, need to keep
+ * it alive until block_job_create() even if bs has no parent. */
+ bdrv_ref(mirror_top_bs);
+ bdrv_drained_begin(bs);
+ bdrv_append(mirror_top_bs, bs, &local_err);
+ bdrv_drained_end(bs);
+
+ if (local_err) {
+ bdrv_unref(mirror_top_bs);
+ error_propagate(errp, local_err);
return;
}
- s->target = blk_new();
- blk_insert_bs(s->target, target);
+ /* Make sure that the source is not resized while the job is running */
+ s = block_job_create(job_id, driver, mirror_top_bs,
+ BLK_PERM_CONSISTENT_READ,
+ BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED |
+ BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD, speed,
+ creation_flags, cb, opaque, errp);
+ bdrv_unref(mirror_top_bs);
+ if (!s) {
+ goto fail;
+ }
+ s->source = bs;
+ s->mirror_top_bs = mirror_top_bs;
+
+ /* No resize for the target either; while the mirror is still running, a
+ * consistent read isn't necessarily possible. We could possibly allow
+ * writes and graph modifications, though it would likely defeat the
+ * purpose of a mirror, so leave them blocked for now.
+ *
+ * In the case of active commit, things look a bit different, though,
+ * because the target is an already populated backing file in active use.
+ * We can allow anything except resize there.*/
+ target_is_backing = bdrv_chain_contains(bs, target);
+ target_graph_mod = (backing_mode != MIRROR_LEAVE_BACKING_CHAIN);
+ s->target = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE |
+ (target_graph_mod ? BLK_PERM_GRAPH_MOD : 0),
+ BLK_PERM_WRITE_UNCHANGED |
+ (target_is_backing ? BLK_PERM_CONSISTENT_READ |
+ BLK_PERM_WRITE |
+ BLK_PERM_GRAPH_MOD : 0));
+ ret = blk_insert_bs(s->target, target, errp);
+ if (ret < 0) {
+ goto fail;
+ }
s->replaces = g_strdup(replaces);
s->on_source_error = on_source_error;
s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
if (!s->dirty_bitmap) {
- g_free(s->replaces);
- blk_unref(s->target);
- block_job_unref(&s->common);
- return;
+ goto fail;
}
- block_job_add_bdrv(&s->common, target);
+ /* Required permissions are already taken with blk_new() */
+ block_job_add_bdrv(&s->common, "target", target, 0, BLK_PERM_ALL,
+ &error_abort);
+
/* In commit_active_start() all intermediate nodes disappear, so
* any jobs in them must be blocked */
- if (bdrv_chain_contains(bs, target)) {
+ if (target_is_backing) {
BlockDriverState *iter;
for (iter = backing_bs(bs); iter != target; iter = backing_bs(iter)) {
- block_job_add_bdrv(&s->common, 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 (== target). */
+ ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
+ BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
+ errp);
+ if (ret < 0) {
+ goto fail;
+ }
}
}
trace_mirror_start(bs, s, opaque);
block_job_start(&s->common);
+ return;
+
+fail:
+ if (s) {
+ g_free(s->replaces);
+ blk_unref(s->target);
+ block_job_unref(&s->common);
+ }
+
+ bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL,
+ &error_abort);
+ bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort);
}
void mirror_start(const char *job_id, BlockDriverState *bs,
MirrorSyncMode mode, BlockMirrorBackingMode backing_mode,
BlockdevOnError on_source_error,
BlockdevOnError on_target_error,
- bool unmap, Error **errp)
+ bool unmap, const char *filter_node_name, Error **errp)
{
bool is_none_mode;
BlockDriverState *base;
mirror_start_job(job_id, bs, BLOCK_JOB_DEFAULT, target, replaces,
speed, granularity, buf_size, backing_mode,
on_source_error, on_target_error, unmap, NULL, NULL, errp,
- &mirror_job_driver, is_none_mode, base, false);
+ &mirror_job_driver, is_none_mode, base, false,
+ filter_node_name);
}
void commit_active_start(const char *job_id, BlockDriverState *bs,
BlockDriverState *base, int creation_flags,
int64_t speed, BlockdevOnError on_error,
+ const char *filter_node_name,
BlockCompletionFunc *cb, void *opaque, Error **errp,
bool auto_complete)
{
- int64_t length, base_length;
int orig_base_flags;
- int ret;
Error *local_err = NULL;
orig_base_flags = bdrv_get_flags(base);
return;
}
- length = bdrv_getlength(bs);
- if (length < 0) {
- error_setg_errno(errp, -length,
- "Unable to determine length of %s", bs->filename);
- goto error_restore_flags;
- }
-
- base_length = bdrv_getlength(base);
- if (base_length < 0) {
- error_setg_errno(errp, -base_length,
- "Unable to determine length of %s", base->filename);
- goto error_restore_flags;
- }
-
- if (length > base_length) {
- ret = bdrv_truncate(base, length);
- if (ret < 0) {
- error_setg_errno(errp, -ret,
- "Top image %s is larger than base image %s, and "
- "resize of base image failed",
- bs->filename, base->filename);
- goto error_restore_flags;
- }
- }
-
mirror_start_job(job_id, bs, creation_flags, base, NULL, speed, 0, 0,
MIRROR_LEAVE_BACKING_CHAIN,
on_error, on_error, true, cb, opaque, &local_err,
- &commit_active_job_driver, false, base, auto_complete);
+ &commit_active_job_driver, false, base, auto_complete,
+ filter_node_name);
if (local_err) {
error_propagate(errp, local_err);
goto error_restore_flags;
projects / mirror_qemu.git / blobdiff