From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57789) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XlbkB-00013Q-7U for qemu-devel@nongnu.org; Tue, 04 Nov 2014 05:53:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xlbk6-0006hE-11 for qemu-devel@nongnu.org; Tue, 04 Nov 2014 05:53:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44692) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xlbk5-0006h2-OG for qemu-devel@nongnu.org; Tue, 04 Nov 2014 05:53:41 -0500 Message-ID: <5458B021.8060100@redhat.com> Date: Tue, 04 Nov 2014 11:53:21 +0100 From: Max Reitz MIME-Version: 1.0 References: <1414639364-4499-1-git-send-email-famz@redhat.com> <1414639364-4499-8-git-send-email-famz@redhat.com> In-Reply-To: <1414639364-4499-8-git-send-email-famz@redhat.com> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v6 07/10] qmp: Add support of "dirty-bitmap" sync mode for drive-backup List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng , qemu-devel@nongnu.org Cc: Kevin Wolf , Benoit Canet , Vladimir Sementsov-Ogievskij , Markus Armbruster , Luiz Capitulino , John Snow , Stefan Hajnoczi , Jd , Paolo Bonzini On 2014-10-30 at 04:22, Fam Zheng wrote: > For "dirty-bitmap" sync mode, the block job will iterate through the > given dirty bitmap to decide if a sector needs backup (backup all the > dirty clusters and skip clean ones), just as allocation conditions of > "top" sync mode. > > There are two bitmap use modes for sync=dirty-bitmap: > > - reset: backup job makes a copy of bitmap and resets the original > one. > - consume: backup job makes the original anonymous (invisible to user) > and releases it after use. > > Signed-off-by: Fam Zheng > --- > block/backup.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++- > block/mirror.c | 4 ++++ > blockdev.c | 9 +++++++- > hmp.c | 4 +++- > include/block/block_int.h | 4 ++++ > qapi/block-core.json | 30 ++++++++++++++++++++++---- > qmp-commands.hx | 7 +++--- > 7 files changed, 102 insertions(+), 10 deletions(-) > > diff --git a/block/backup.c b/block/backup.c > index e334740..4870694 100644 > --- a/block/backup.c > +++ b/block/backup.c > @@ -37,6 +37,10 @@ typedef struct CowRequest { > typedef struct BackupBlockJob { > BlockJob common; > BlockDriverState *target; > + /* bitmap for sync=dirty-bitmap */ > + BdrvDirtyBitmap *sync_bitmap; > + /* dirty bitmap granularity */ > + int sync_bitmap_gran; > MirrorSyncMode sync_mode; > RateLimit limit; > BlockdevOnError on_source_error; > @@ -263,7 +267,7 @@ static void coroutine_fn backup_run(void *opaque) > job->common.busy = true; > } > } else { > - /* Both FULL and TOP SYNC_MODE's require copying.. */ > + /* full, top and dirty_bitmap modes require copying.. */ > for (; start < end; start++) { > bool error_is_read; > > @@ -317,7 +321,21 @@ static void coroutine_fn backup_run(void *opaque) > if (alloced == 0) { > continue; > } > + } else if (job->sync_mode == MIRROR_SYNC_MODE_DIRTY_BITMAP) { > + int i, dirty = 0; > + for (i = 0; i < BACKUP_SECTORS_PER_CLUSTER; > + i += job->sync_bitmap_gran) { ->sync_bitmap_gran should be a sector count here... [1] > + if (bdrv_get_dirty(bs, job->sync_bitmap, > + start * BACKUP_SECTORS_PER_CLUSTER + i)) { > + dirty = 1; > + break; > + } > + } > + if (!dirty) { > + continue; > + } > } > + > /* FULL sync mode we copy the whole drive. */ > ret = backup_do_cow(bs, start * BACKUP_SECTORS_PER_CLUSTER, > BACKUP_SECTORS_PER_CLUSTER, &error_is_read); > @@ -341,6 +359,9 @@ static void coroutine_fn backup_run(void *opaque) > qemu_co_rwlock_wrlock(&job->flush_rwlock); > qemu_co_rwlock_unlock(&job->flush_rwlock); > > + if (job->sync_bitmap) { > + bdrv_release_dirty_bitmap(bs, job->sync_bitmap); > + } > hbitmap_free(job->bitmap); > > bdrv_iostatus_disable(target); > @@ -351,12 +372,15 @@ static void coroutine_fn backup_run(void *opaque) > > void backup_start(BlockDriverState *bs, BlockDriverState *target, > int64_t speed, MirrorSyncMode sync_mode, > + BdrvDirtyBitmap *sync_bitmap, > + BitmapUseMode bitmap_mode, > BlockdevOnError on_source_error, > BlockdevOnError on_target_error, > BlockCompletionFunc *cb, void *opaque, > Error **errp) > { > int64_t len; > + BdrvDirtyBitmap *original; > > assert(bs); > assert(target); > @@ -369,6 +393,28 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target, > return; > } > > + if (sync_mode == MIRROR_SYNC_MODE_DIRTY_BITMAP) { > + if (!sync_bitmap) { > + error_setg(errp, "must provide a valid bitmap name for " > + "\"dirty-bitmap\" sync mode"); > + return; > + } How about an error when sync_mode != MIRROR_SYNC_MODE_DIRTY_BITMAP and sync_bitmap != NULL? It's not really fatal, but I wouldn't call it a valid combination either. > + > + switch (bitmap_mode) { > + case BITMAP_USE_MODE_RESET: > + original = sync_bitmap; > + sync_bitmap = bdrv_copy_dirty_bitmap(bs, sync_bitmap, NULL); > + bdrv_reset_dirty_bitmap(bs, original); > + break; > + case BITMAP_USE_MODE_CONSUME: > + bdrv_dirty_bitmap_make_anon(bs, sync_bitmap); > + break; > + default: > + assert(0); Better use abort() directly (or g_assert_not_reached(), which however suffers from the same problem as assert(0) which is NDEBUG or the equivalent for glib). > + } > + bdrv_disable_dirty_bitmap(bs, sync_bitmap); > + } > + > len = bdrv_getlength(bs); > if (len < 0) { > error_setg_errno(errp, -len, "unable to get length for '%s'", > @@ -386,6 +432,12 @@ void backup_start(BlockDriverState *bs, BlockDriverState *target, > job->on_target_error = on_target_error; > job->target = target; > job->sync_mode = sync_mode; > + job->sync_bitmap = sync_mode == MIRROR_SYNC_MODE_DIRTY_BITMAP ? > + sync_bitmap : NULL; > + if (sync_bitmap) { > + job->sync_bitmap_gran = > + bdrv_dirty_bitmap_granularity(bs, job->sync_bitmap); [1] so this should return a sector count (relevant for patch 3); although I'd still personally prefer it to return a byte count which is converted to sectors here (but it doesn't matter from a technical perspective). > + } > job->common.len = len; > job->common.co = qemu_coroutine_create(backup_run); > qemu_coroutine_enter(job->common.co, job); > diff --git a/block/mirror.c b/block/mirror.c > index cecd448..8dfd908 100644 > --- a/block/mirror.c > +++ b/block/mirror.c > @@ -679,6 +679,10 @@ void mirror_start(BlockDriverState *bs, BlockDriverState *target, > bool is_none_mode; > BlockDriverState *base; > > + if (mode == MIRROR_SYNC_MODE_DIRTY_BITMAP) { > + error_setg(errp, "Sync mode 'dirty-bitmap' not supported"); > + return; > + } > is_none_mode = mode == MIRROR_SYNC_MODE_NONE; > base = mode == MIRROR_SYNC_MODE_TOP ? bs->backing_hd : NULL; > mirror_start_job(bs, target, replaces, > diff --git a/blockdev.c b/blockdev.c > index c7e98ad..fca909b 100644 > --- a/blockdev.c > +++ b/blockdev.c > @@ -1463,6 +1463,8 @@ static void drive_backup_prepare(BlkTransactionState *common, Error **errp) > backup->sync, > backup->has_mode, backup->mode, > backup->has_speed, backup->speed, > + backup->has_bitmap, backup->bitmap, > + backup->has_bitmap_use_mode, backup->bitmap_use_mode, > backup->has_on_source_error, backup->on_source_error, > backup->has_on_target_error, backup->on_target_error, > &local_err); > @@ -2186,6 +2188,8 @@ void qmp_drive_backup(const char *device, const char *target, > enum MirrorSyncMode sync, > bool has_mode, enum NewImageMode mode, > bool has_speed, int64_t speed, > + bool has_bitmap, const char *bitmap, > + bool has_bitmap_use_mode, enum BitmapUseMode bitmap_mode, > bool has_on_source_error, BlockdevOnError on_source_error, > bool has_on_target_error, BlockdevOnError on_target_error, > Error **errp) > @@ -2282,7 +2286,10 @@ void qmp_drive_backup(const char *device, const char *target, > return; > } > This conflicts with Stefan's blockjob/dataplane series (can be easily fixed, though). > - backup_start(bs, target_bs, speed, sync, on_source_error, on_target_error, > + backup_start(bs, target_bs, speed, sync, > + has_bitmap ? bdrv_find_dirty_bitmap(bs, bitmap) : NULL, Shouldn't we be checking the return value of bdrv_find_dirty_bitmap() here? I know backup_start() does a check itself, but I'd prefer a check here, too, nonetheless. > + has_bitmap_use_mode ? bitmap_mode : BITMAP_USE_MODE_RESET, > + on_source_error, on_target_error, > block_job_cb, bs, &local_err); > if (local_err != NULL) { > bdrv_unref(target_bs); > diff --git a/hmp.c b/hmp.c > index 63d7686..bc5a2d2 100644 > --- a/hmp.c > +++ b/hmp.c > @@ -966,7 +966,9 @@ void hmp_drive_backup(Monitor *mon, const QDict *qdict) > > qmp_drive_backup(device, filename, !!format, format, > full ? MIRROR_SYNC_MODE_FULL : MIRROR_SYNC_MODE_TOP, > - true, mode, false, 0, false, 0, false, 0, &err); > + true, mode, false, 0, false, NULL, > + false, 0, > + false, 0, false, 0, &err); > hmp_handle_error(mon, &err); > } > > diff --git a/include/block/block_int.h b/include/block/block_int.h > index 8898c6c..0671c89 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -567,6 +567,8 @@ void mirror_start(BlockDriverState *bs, BlockDriverState *target, > * @target: Block device to write to. > * @speed: The maximum speed, in bytes per second, or 0 for unlimited. > * @sync_mode: What parts of the disk image should be copied to the destination. > + * @sync_bitmap: The name of dirty bitmap if sync_mode is > + * MIRROR_SYNC_MODE_DIRTY_BITMAP. It's not the name, it's the bitmap itself. Also, documentation for bitmap_mode is missing. > * @on_source_error: The action to take upon error reading from the source. > * @on_target_error: The action to take upon error writing to the target. > * @cb: Completion function for the job. > @@ -577,6 +579,8 @@ void mirror_start(BlockDriverState *bs, BlockDriverState *target, > */ > void backup_start(BlockDriverState *bs, BlockDriverState *target, > int64_t speed, MirrorSyncMode sync_mode, > + BdrvDirtyBitmap *sync_bitmap, > + BitmapUseMode bitmap_mode, > BlockdevOnError on_source_error, > BlockdevOnError on_target_error, > BlockCompletionFunc *cb, void *opaque, > diff --git a/qapi/block-core.json b/qapi/block-core.json > index 97c31bf..e225220 100644 > --- a/qapi/block-core.json > +++ b/qapi/block-core.json > @@ -473,7 +473,7 @@ > # Since: 1.3 > ## > { 'enum': 'MirrorSyncMode', > - 'data': ['top', 'full', 'none'] } > + 'data': ['top', 'full', 'none', 'dirty-bitmap'] } > > ## > # @BlockJobType: > @@ -634,6 +634,21 @@ > '*format': 'str', '*mode': 'NewImageMode' } } > > ## > +# @BitmapUseMode > +# > +# An enumeration that tells QEMU what operation to take when using a bitmap > +# in drive backup sync mode. Did you mean "when using a bitmap in drive backup sync mode dirty-bitmap"? (or just "when using a bitmap for drive-backup") > +# > +# @consume: QEMU should just consume the bitmap and release it after using > +# > +# @reset: QEMU should reset the dirty bitmap > +# > +# Since: 2.3 > +## > +{ 'enum': 'BitmapUseMode', > +'data': [ 'consume', 'reset' ] } > + > +## > # @DriveBackup > # > # @device: the name of the device which should be copied. > @@ -646,14 +661,20 @@ > # probe if @mode is 'existing', else the format of the source > # > # @sync: what parts of the disk image should be copied to the destination > -# (all the disk, only the sectors allocated in the topmost image, or > -# only new I/O). > +# (all the disk, only the sectors allocated in the topmost image, from a > +# dirty bitmap, or only new I/O). > # > # @mode: #optional whether and how QEMU should create a new image, default is > # 'absolute-paths'. > # > # @speed: #optional the maximum speed, in bytes per second > # > +# @bitmap: #optional the name of dirty bitmap if sync is "dirty-bitmap" > +# (Since 2.3) > +# > +# @bitmap-use-mode: #optional which operation to take when consuming @bitmap, > +# default is reset. (Since 2.1) *2.3 Max > +# > # @on-source-error: #optional the action to take on an error on the source, > # default 'report'. 'stop' and 'enospc' can only be used > # if the block device supports io-status (see BlockInfo). > @@ -671,7 +692,8 @@ > { 'type': 'DriveBackup', > 'data': { 'device': 'str', 'target': 'str', '*format': 'str', > 'sync': 'MirrorSyncMode', '*mode': 'NewImageMode', > - '*speed': 'int', > + '*speed': 'int', '*bitmap': 'str', > + '*bitmap-use-mode': 'BitmapUseMode', > '*on-source-error': 'BlockdevOnError', > '*on-target-error': 'BlockdevOnError' } } > > diff --git a/qmp-commands.hx b/qmp-commands.hx > index 6d0c944..75035e1 100644 > --- a/qmp-commands.hx > +++ b/qmp-commands.hx > @@ -1048,7 +1048,7 @@ EQMP > { > .name = "drive-backup", > .args_type = "sync:s,device:B,target:s,speed:i?,mode:s?,format:s?," > - "on-source-error:s?,on-target-error:s?", > + "bitmap:s?,on-source-error:s?,on-target-error:s?", > .mhandler.cmd_new = qmp_marshal_input_drive_backup, > }, > > @@ -1075,8 +1075,9 @@ Arguments: > (json-string, optional) > - "sync": what parts of the disk image should be copied to the destination; > possibilities include "full" for all the disk, "top" for only the sectors > - allocated in the topmost image, or "none" to only replicate new I/O > - (MirrorSyncMode). > + allocated in the topmost image, "dirty-bitmap" for only the dirty sectors in > + the bitmap, or "none" to only replicate new I/O (MirrorSyncMode). > +- "bitmap": dirty bitmap name for sync==dirty-bitmap > - "mode": whether and how QEMU should create a new image > (NewImageMode, optional, default 'absolute-paths') > - "speed": the maximum speed, in bytes per second (json-int, optional)