qemu-e2k/block/backup.c

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block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
/*
* QEMU backup
*
* Copyright (C) 2013 Proxmox Server Solutions
block/backup: use backup-top instead of write notifiers Drop write notifiers and use filter node instead. = Changes = 1. Add filter-node-name argument for backup qmp api. We have to do it in this commit, as 257 needs to be fixed. 2. There are no more write notifiers here, so is_write_notifier parameter is dropped from block-copy paths. 3. To sync with in-flight requests at job finish we now have drained removing of the filter, we don't need rw-lock. 4. Block-copy is now using BdrvChildren instead of BlockBackends 5. As backup-top owns these children, we also move block-copy state into backup-top's ownership. = Iotest changes = 56: op-blocker doesn't shoot now, as we set it on source, but then check on filter, when trying to start second backup. To keep the test we instead can catch another collision: both jobs will get 'drive0' job-id, as job-id parameter is unspecified. To prevent interleaving with file-posix locks (as they are dependent on config) let's use another target for second backup. Also, it's obvious now that we'd like to drop this op-blocker at all and add a test-case for two backups from one node (to different destinations) actually works. But not in these series. 141: Output changed: prepatch, "Node is in use" comes from bdrv_has_blk check inside qmp_blockdev_del. But we've dropped block-copy blk objects, so no more blk objects on source bs (job blk is on backup-top filter bs). New message is from op-blocker, which is the next check in qmp_blockdev_add. 257: The test wants to emulate guest write during backup. They should go to filter node, not to original source node, of course. Therefore we need to specify filter node name and use it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20191001131409.14202-6-vsementsov@virtuozzo.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-01 15:14:09 +02:00
* Copyright (c) 2019 Virtuozzo International GmbH.
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
*
* Authors:
* Dietmar Maurer (dietmar@proxmox.com)
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
#include "trace.h"
#include "block/block.h"
#include "block/block_int.h"
#include "block/blockjob_int.h"
#include "block/block_backup.h"
#include "block/block-copy.h"
2016-03-14 09:01:28 +01:00
#include "qapi/error.h"
#include "qapi/qmp/qerror.h"
#include "qemu/cutils.h"
#include "sysemu/block-backend.h"
#include "qemu/bitmap.h"
#include "qemu/error-report.h"
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
block: rename backup-top to copy-before-write We are going to convert backup_top to full featured public filter, which can be used in separate of backup job. Start from renaming from "how it used" to "what it does". While updating comments in 283 iotest, drop and rephrase also things about ".active", as this field is now dropped, and filter doesn't have "inactive" mode. Note that this change may be considered as incompatible interface change, as backup-top filter format name was visible through query-block and query-named-block-nodes. Still, consider the following reasoning: 1. backup-top was never documented, so if someone depends on format name (for driver that can't be used other than it is automatically inserted on backup job start), it's a kind of "undocumented feature use". So I think we are free to change it. 2. There is a hope, that there is no such users: it's a lot more native to give a good node-name to backup-top filter if need to operate with it somehow, and don't touch format name. 3. Another "incompatible" change in further commit would be moving copy-before-write filter from using backing child to file child. And this is even more reasonable than renaming: for now all public filters are file-child based. So, it's a risky change, but risk seems small and good interface worth it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210824083856.17408-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2021-08-24 10:38:27 +02:00
#include "block/copy-before-write.h"
block/backup: use backup-top instead of write notifiers Drop write notifiers and use filter node instead. = Changes = 1. Add filter-node-name argument for backup qmp api. We have to do it in this commit, as 257 needs to be fixed. 2. There are no more write notifiers here, so is_write_notifier parameter is dropped from block-copy paths. 3. To sync with in-flight requests at job finish we now have drained removing of the filter, we don't need rw-lock. 4. Block-copy is now using BdrvChildren instead of BlockBackends 5. As backup-top owns these children, we also move block-copy state into backup-top's ownership. = Iotest changes = 56: op-blocker doesn't shoot now, as we set it on source, but then check on filter, when trying to start second backup. To keep the test we instead can catch another collision: both jobs will get 'drive0' job-id, as job-id parameter is unspecified. To prevent interleaving with file-posix locks (as they are dependent on config) let's use another target for second backup. Also, it's obvious now that we'd like to drop this op-blocker at all and add a test-case for two backups from one node (to different destinations) actually works. But not in these series. 141: Output changed: prepatch, "Node is in use" comes from bdrv_has_blk check inside qmp_blockdev_del. But we've dropped block-copy blk objects, so no more blk objects on source bs (job blk is on backup-top filter bs). New message is from op-blocker, which is the next check in qmp_blockdev_add. 257: The test wants to emulate guest write during backup. They should go to filter node, not to original source node, of course. Therefore we need to specify filter node name and use it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20191001131409.14202-6-vsementsov@virtuozzo.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-01 15:14:09 +02:00
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
typedef struct BackupBlockJob {
BlockJob common;
block: rename backup-top to copy-before-write We are going to convert backup_top to full featured public filter, which can be used in separate of backup job. Start from renaming from "how it used" to "what it does". While updating comments in 283 iotest, drop and rephrase also things about ".active", as this field is now dropped, and filter doesn't have "inactive" mode. Note that this change may be considered as incompatible interface change, as backup-top filter format name was visible through query-block and query-named-block-nodes. Still, consider the following reasoning: 1. backup-top was never documented, so if someone depends on format name (for driver that can't be used other than it is automatically inserted on backup job start), it's a kind of "undocumented feature use". So I think we are free to change it. 2. There is a hope, that there is no such users: it's a lot more native to give a good node-name to backup-top filter if need to operate with it somehow, and don't touch format name. 3. Another "incompatible" change in further commit would be moving copy-before-write filter from using backing child to file child. And this is even more reasonable than renaming: for now all public filters are file-child based. So, it's a risky change, but risk seems small and good interface worth it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210824083856.17408-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2021-08-24 10:38:27 +02:00
BlockDriverState *cbw;
BlockDriverState *source_bs;
BlockDriverState *target_bs;
BdrvDirtyBitmap *sync_bitmap;
Implement sync modes for drive-backup. This patch adds sync-modes to the drive-backup interface and implements the FULL, NONE and TOP modes of synchronization. FULL performs as before copying the entire contents of the drive while preserving the point-in-time using CoW. NONE only copies new writes to the target drive. TOP copies changes to the topmost drive image and preserves the point-in-time using CoW. For sync mode TOP are creating a new target image using the same backing file as the original disk image. Then any new data that has been laid on top of it since creation is copied in the main backup_run() loop. There is an extra check in the 'TOP' case so that we don't bother to copy all the data of the backing file as it already exists in the target. This is where the bdrv_co_is_allocated() is used to determine if the data exists in the topmost layer or below. Also any new data being written is intercepted via the write_notifier hook which ends up calling backup_do_cow() to copy old data out before it gets overwritten. For mode 'NONE' we create the new target image and only copy in the original data from the disk image starting from the time the call was made. This preserves the point in time data by only copying the parts that are *going to change* to the target image. This way we can reconstruct the final image by checking to see if the given block exists in the new target image first, and if it does not, you can get it from the original image. This is basically an optimization allowing you to do point-in-time snapshots with low overhead vs the 'FULL' version. Since there is no old data to copy out the loop in backup_run() for the NONE case just calls qemu_coroutine_yield() which only wakes up after an event (usually cancel in this case). The rest is handled by the before_write notifier which again calls backup_do_cow() to write out the old data so it can be preserved. Signed-off-by: Ian Main <imain@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-07-26 20:39:04 +02:00
MirrorSyncMode sync_mode;
BitmapSyncMode bitmap_mode;
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
BlockdevOnError on_source_error;
BlockdevOnError on_target_error;
uint64_t len;
int64_t cluster_size;
BackupPerf perf;
BlockCopyState *bcs;
bool wait;
BlockCopyCallState *bg_bcs_call;
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
} BackupBlockJob;
static const BlockJobDriver backup_job_driver;
static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
{
BdrvDirtyBitmap *bm;
bool sync = (((ret == 0) || (job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS)) \
&& (job->bitmap_mode != BITMAP_SYNC_MODE_NEVER));
if (sync) {
/*
* We succeeded, or we always intended to sync the bitmap.
* Delete this bitmap and install the child.
*/
bm = bdrv_dirty_bitmap_abdicate(job->sync_bitmap, NULL);
} else {
/*
* We failed, or we never intended to sync the bitmap anyway.
* Merge the successor back into the parent, keeping all data.
*/
bm = bdrv_reclaim_dirty_bitmap(job->sync_bitmap, NULL);
}
assert(bm);
if (ret < 0 && job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS) {
/* If we failed and synced, merge in the bits we didn't copy: */
bdrv_dirty_bitmap_merge_internal(bm, block_copy_dirty_bitmap(job->bcs),
NULL, true);
}
}
static void backup_commit(Job *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
if (s->sync_bitmap) {
backup_cleanup_sync_bitmap(s, 0);
}
}
static void backup_abort(Job *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
if (s->sync_bitmap) {
backup_cleanup_sync_bitmap(s, -1);
}
}
static void backup_clean(Job *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
block_job_remove_all_bdrv(&s->common);
block: rename backup-top to copy-before-write We are going to convert backup_top to full featured public filter, which can be used in separate of backup job. Start from renaming from "how it used" to "what it does". While updating comments in 283 iotest, drop and rephrase also things about ".active", as this field is now dropped, and filter doesn't have "inactive" mode. Note that this change may be considered as incompatible interface change, as backup-top filter format name was visible through query-block and query-named-block-nodes. Still, consider the following reasoning: 1. backup-top was never documented, so if someone depends on format name (for driver that can't be used other than it is automatically inserted on backup job start), it's a kind of "undocumented feature use". So I think we are free to change it. 2. There is a hope, that there is no such users: it's a lot more native to give a good node-name to backup-top filter if need to operate with it somehow, and don't touch format name. 3. Another "incompatible" change in further commit would be moving copy-before-write filter from using backing child to file child. And this is even more reasonable than renaming: for now all public filters are file-child based. So, it's a risky change, but risk seems small and good interface worth it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210824083856.17408-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2021-08-24 10:38:27 +02:00
bdrv_cbw_drop(s->cbw);
}
void backup_do_checkpoint(BlockJob *job, Error **errp)
{
BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
assert(block_job_driver(job) == &backup_job_driver);
if (backup_job->sync_mode != MIRROR_SYNC_MODE_NONE) {
error_setg(errp, "The backup job only supports block checkpoint in"
" sync=none mode");
return;
}
bdrv_set_dirty_bitmap(block_copy_dirty_bitmap(backup_job->bcs), 0,
backup_job->len);
}
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
static BlockErrorAction backup_error_action(BackupBlockJob *job,
bool read, int error)
{
if (read) {
return block_job_error_action(&job->common, job->on_source_error,
true, error);
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
} else {
return block_job_error_action(&job->common, job->on_target_error,
false, error);
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
}
}
static void coroutine_fn backup_block_copy_callback(void *opaque)
{
BackupBlockJob *s = opaque;
if (s->wait) {
s->wait = false;
aio_co_wake(s->common.job.co);
} else {
job_enter(&s->common.job);
}
}
static int coroutine_fn backup_loop(BackupBlockJob *job)
{
BlockCopyCallState *s = NULL;
int ret = 0;
bool error_is_read;
BlockErrorAction act;
while (true) { /* retry loop */
job->bg_bcs_call = s = block_copy_async(job->bcs, 0,
QEMU_ALIGN_UP(job->len, job->cluster_size),
job->perf.max_workers, job->perf.max_chunk,
backup_block_copy_callback, job);
while (!block_copy_call_finished(s) &&
!job_is_cancelled(&job->common.job))
{
job_yield(&job->common.job);
}
if (!block_copy_call_finished(s)) {
assert(job_is_cancelled(&job->common.job));
/*
* Note that we can't use job_yield() here, as it doesn't work for
* cancelled job.
*/
block_copy_call_cancel(s);
job->wait = true;
qemu_coroutine_yield();
assert(block_copy_call_finished(s));
ret = 0;
goto out;
}
if (job_is_cancelled(&job->common.job) ||
block_copy_call_succeeded(s))
{
ret = 0;
goto out;
}
if (block_copy_call_cancelled(s)) {
/*
* Job is not cancelled but only block-copy call. This is possible
* after job pause. Now the pause is finished, start new block-copy
* iteration.
*/
block_copy_call_free(s);
continue;
}
/* The only remaining case is failed block-copy call. */
assert(block_copy_call_failed(s));
ret = block_copy_call_status(s, &error_is_read);
act = backup_error_action(job, error_is_read, -ret);
switch (act) {
case BLOCK_ERROR_ACTION_REPORT:
goto out;
case BLOCK_ERROR_ACTION_STOP:
/*
* Go to pause prior to starting new block-copy call on the next
* iteration.
*/
job_pause_point(&job->common.job);
break;
case BLOCK_ERROR_ACTION_IGNORE:
/* Proceed to new block-copy call to retry. */
break;
default:
abort();
}
block_copy_call_free(s);
}
out:
block_copy_call_free(s);
job->bg_bcs_call = NULL;
return ret;
}
static void backup_init_bcs_bitmap(BackupBlockJob *job)
{
bool ret;
uint64_t estimate;
BdrvDirtyBitmap *bcs_bitmap = block_copy_dirty_bitmap(job->bcs);
if (job->sync_mode == MIRROR_SYNC_MODE_BITMAP) {
bdrv_clear_dirty_bitmap(bcs_bitmap, NULL);
ret = bdrv_dirty_bitmap_merge_internal(bcs_bitmap, job->sync_bitmap,
NULL, true);
assert(ret);
} else if (job->sync_mode == MIRROR_SYNC_MODE_TOP) {
/*
* We can't hog the coroutine to initialize this thoroughly.
* Set a flag and resume work when we are able to yield safely.
*/
block_copy_set_skip_unallocated(job->bcs, true);
}
estimate = bdrv_get_dirty_count(bcs_bitmap);
job_progress_set_remaining(&job->common.job, estimate);
}
static int coroutine_fn backup_run(Job *job, Error **errp)
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
int ret;
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
backup_init_bcs_bitmap(s);
if (s->sync_mode == MIRROR_SYNC_MODE_TOP) {
int64_t offset = 0;
int64_t count;
for (offset = 0; offset < s->len; ) {
if (job_is_cancelled(job)) {
return -ECANCELED;
}
job_pause_point(job);
if (job_is_cancelled(job)) {
return -ECANCELED;
}
ret = block_copy_reset_unallocated(s->bcs, offset, &count);
if (ret < 0) {
return ret;
}
offset += count;
}
block_copy_set_skip_unallocated(s->bcs, false);
}
if (s->sync_mode == MIRROR_SYNC_MODE_NONE) {
/*
* All bits are set in bcs bitmap to allow any cluster to be copied.
* This does not actually require them to be copied.
*/
while (!job_is_cancelled(job)) {
/*
* Yield until the job is cancelled. We just let our before_write
* notify callback service CoW requests.
*/
job_yield(job);
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
}
Implement sync modes for drive-backup. This patch adds sync-modes to the drive-backup interface and implements the FULL, NONE and TOP modes of synchronization. FULL performs as before copying the entire contents of the drive while preserving the point-in-time using CoW. NONE only copies new writes to the target drive. TOP copies changes to the topmost drive image and preserves the point-in-time using CoW. For sync mode TOP are creating a new target image using the same backing file as the original disk image. Then any new data that has been laid on top of it since creation is copied in the main backup_run() loop. There is an extra check in the 'TOP' case so that we don't bother to copy all the data of the backing file as it already exists in the target. This is where the bdrv_co_is_allocated() is used to determine if the data exists in the topmost layer or below. Also any new data being written is intercepted via the write_notifier hook which ends up calling backup_do_cow() to copy old data out before it gets overwritten. For mode 'NONE' we create the new target image and only copy in the original data from the disk image starting from the time the call was made. This preserves the point in time data by only copying the parts that are *going to change* to the target image. This way we can reconstruct the final image by checking to see if the given block exists in the new target image first, and if it does not, you can get it from the original image. This is basically an optimization allowing you to do point-in-time snapshots with low overhead vs the 'FULL' version. Since there is no old data to copy out the loop in backup_run() for the NONE case just calls qemu_coroutine_yield() which only wakes up after an event (usually cancel in this case). The rest is handled by the before_write notifier which again calls backup_do_cow() to write out the old data so it can be preserved. Signed-off-by: Ian Main <imain@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-07-26 20:39:04 +02:00
} else {
return backup_loop(s);
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
}
return 0;
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
}
static void coroutine_fn backup_pause(Job *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
if (s->bg_bcs_call && !block_copy_call_finished(s->bg_bcs_call)) {
block_copy_call_cancel(s->bg_bcs_call);
s->wait = true;
qemu_coroutine_yield();
}
}
static void coroutine_fn backup_set_speed(BlockJob *job, int64_t speed)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common);
/*
* block_job_set_speed() is called first from block_job_create(), when we
* don't yet have s->bcs.
*/
if (s->bcs) {
block_copy_set_speed(s->bcs, speed);
if (s->bg_bcs_call) {
block_copy_kick(s->bg_bcs_call);
}
}
}
jobs: Give Job.force_cancel more meaning We largely have two cancel modes for jobs: First, there is actual cancelling. The job is terminated as soon as possible, without trying to reach a consistent result. Second, we have mirror in the READY state. Technically, the job is not really cancelled, but it just is a different completion mode. The job can still run for an indefinite amount of time while it tries to reach a consistent result. We want to be able to clearly distinguish which cancel mode a job is in (when it has been cancelled). We can use Job.force_cancel for this, but right now it only reflects cancel requests from the user with force=true, but clearly, jobs that do not even distinguish between force=false and force=true are effectively always force-cancelled. So this patch has Job.force_cancel signify whether the job will terminate as soon as possible (force_cancel=true) or whether it will effectively remain running despite being "cancelled" (force_cancel=false). To this end, we let jobs that provide JobDriver.cancel() tell the generic job code whether they will terminate as soon as possible or not, and for jobs that do not provide that method we assume they will. Signed-off-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20211006151940.214590-7-hreitz@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-10-06 17:19:33 +02:00
static bool backup_cancel(Job *job, bool force)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
bdrv_cancel_in_flight(s->target_bs);
jobs: Give Job.force_cancel more meaning We largely have two cancel modes for jobs: First, there is actual cancelling. The job is terminated as soon as possible, without trying to reach a consistent result. Second, we have mirror in the READY state. Technically, the job is not really cancelled, but it just is a different completion mode. The job can still run for an indefinite amount of time while it tries to reach a consistent result. We want to be able to clearly distinguish which cancel mode a job is in (when it has been cancelled). We can use Job.force_cancel for this, but right now it only reflects cancel requests from the user with force=true, but clearly, jobs that do not even distinguish between force=false and force=true are effectively always force-cancelled. So this patch has Job.force_cancel signify whether the job will terminate as soon as possible (force_cancel=true) or whether it will effectively remain running despite being "cancelled" (force_cancel=false). To this end, we let jobs that provide JobDriver.cancel() tell the generic job code whether they will terminate as soon as possible or not, and for jobs that do not provide that method we assume they will. Signed-off-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20211006151940.214590-7-hreitz@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-10-06 17:19:33 +02:00
return true;
}
static const BlockJobDriver backup_job_driver = {
.job_driver = {
.instance_size = sizeof(BackupBlockJob),
.job_type = JOB_TYPE_BACKUP,
.free = block_job_free,
.user_resume = block_job_user_resume,
.run = backup_run,
.commit = backup_commit,
.abort = backup_abort,
.clean = backup_clean,
.pause = backup_pause,
.cancel = backup_cancel,
},
.set_speed = backup_set_speed,
};
BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
BlockDriverState *target, int64_t speed,
MirrorSyncMode sync_mode, BdrvDirtyBitmap *sync_bitmap,
BitmapSyncMode bitmap_mode,
bool compress,
block/backup: use backup-top instead of write notifiers Drop write notifiers and use filter node instead. = Changes = 1. Add filter-node-name argument for backup qmp api. We have to do it in this commit, as 257 needs to be fixed. 2. There are no more write notifiers here, so is_write_notifier parameter is dropped from block-copy paths. 3. To sync with in-flight requests at job finish we now have drained removing of the filter, we don't need rw-lock. 4. Block-copy is now using BdrvChildren instead of BlockBackends 5. As backup-top owns these children, we also move block-copy state into backup-top's ownership. = Iotest changes = 56: op-blocker doesn't shoot now, as we set it on source, but then check on filter, when trying to start second backup. To keep the test we instead can catch another collision: both jobs will get 'drive0' job-id, as job-id parameter is unspecified. To prevent interleaving with file-posix locks (as they are dependent on config) let's use another target for second backup. Also, it's obvious now that we'd like to drop this op-blocker at all and add a test-case for two backups from one node (to different destinations) actually works. But not in these series. 141: Output changed: prepatch, "Node is in use" comes from bdrv_has_blk check inside qmp_blockdev_del. But we've dropped block-copy blk objects, so no more blk objects on source bs (job blk is on backup-top filter bs). New message is from op-blocker, which is the next check in qmp_blockdev_add. 257: The test wants to emulate guest write during backup. They should go to filter node, not to original source node, of course. Therefore we need to specify filter node name and use it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20191001131409.14202-6-vsementsov@virtuozzo.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-01 15:14:09 +02:00
const char *filter_node_name,
BackupPerf *perf,
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
BlockdevOnError on_source_error,
BlockdevOnError on_target_error,
int creation_flags,
BlockCompletionFunc *cb, void *opaque,
JobTxn *txn, Error **errp)
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
{
int64_t len, target_len;
BackupBlockJob *job = NULL;
int64_t cluster_size;
block: rename backup-top to copy-before-write We are going to convert backup_top to full featured public filter, which can be used in separate of backup job. Start from renaming from "how it used" to "what it does". While updating comments in 283 iotest, drop and rephrase also things about ".active", as this field is now dropped, and filter doesn't have "inactive" mode. Note that this change may be considered as incompatible interface change, as backup-top filter format name was visible through query-block and query-named-block-nodes. Still, consider the following reasoning: 1. backup-top was never documented, so if someone depends on format name (for driver that can't be used other than it is automatically inserted on backup job start), it's a kind of "undocumented feature use". So I think we are free to change it. 2. There is a hope, that there is no such users: it's a lot more native to give a good node-name to backup-top filter if need to operate with it somehow, and don't touch format name. 3. Another "incompatible" change in further commit would be moving copy-before-write filter from using backing child to file child. And this is even more reasonable than renaming: for now all public filters are file-child based. So, it's a risky change, but risk seems small and good interface worth it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210824083856.17408-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2021-08-24 10:38:27 +02:00
BlockDriverState *cbw = NULL;
block/backup: use backup-top instead of write notifiers Drop write notifiers and use filter node instead. = Changes = 1. Add filter-node-name argument for backup qmp api. We have to do it in this commit, as 257 needs to be fixed. 2. There are no more write notifiers here, so is_write_notifier parameter is dropped from block-copy paths. 3. To sync with in-flight requests at job finish we now have drained removing of the filter, we don't need rw-lock. 4. Block-copy is now using BdrvChildren instead of BlockBackends 5. As backup-top owns these children, we also move block-copy state into backup-top's ownership. = Iotest changes = 56: op-blocker doesn't shoot now, as we set it on source, but then check on filter, when trying to start second backup. To keep the test we instead can catch another collision: both jobs will get 'drive0' job-id, as job-id parameter is unspecified. To prevent interleaving with file-posix locks (as they are dependent on config) let's use another target for second backup. Also, it's obvious now that we'd like to drop this op-blocker at all and add a test-case for two backups from one node (to different destinations) actually works. But not in these series. 141: Output changed: prepatch, "Node is in use" comes from bdrv_has_blk check inside qmp_blockdev_del. But we've dropped block-copy blk objects, so no more blk objects on source bs (job blk is on backup-top filter bs). New message is from op-blocker, which is the next check in qmp_blockdev_add. 257: The test wants to emulate guest write during backup. They should go to filter node, not to original source node, of course. Therefore we need to specify filter node name and use it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20191001131409.14202-6-vsementsov@virtuozzo.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-01 15:14:09 +02:00
BlockCopyState *bcs = NULL;
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
assert(bs);
assert(target);
GLOBAL_STATE_CODE();
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
/* QMP interface protects us from these cases */
assert(sync_mode != MIRROR_SYNC_MODE_INCREMENTAL);
assert(sync_bitmap || sync_mode != MIRROR_SYNC_MODE_BITMAP);
if (bs == target) {
error_setg(errp, "Source and target cannot be the same");
return NULL;
}
if (!bdrv_is_inserted(bs)) {
error_setg(errp, "Device is not inserted: %s",
bdrv_get_device_name(bs));
return NULL;
}
if (!bdrv_is_inserted(target)) {
error_setg(errp, "Device is not inserted: %s",
bdrv_get_device_name(target));
return NULL;
}
if (compress && !bdrv_supports_compressed_writes(target)) {
error_setg(errp, "Compression is not supported for this drive %s",
bdrv_get_device_name(target));
return NULL;
}
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
return NULL;
}
if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_BACKUP_TARGET, errp)) {
return NULL;
}
if (perf->max_workers < 1 || perf->max_workers > INT_MAX) {
error_setg(errp, "max-workers must be between 1 and %d", INT_MAX);
return NULL;
}
if (perf->max_chunk < 0) {
error_setg(errp, "max-chunk must be zero (which means no limit) or "
"positive");
return NULL;
}
if (sync_bitmap) {
/* If we need to write to this bitmap, check that we can: */
if (bitmap_mode != BITMAP_SYNC_MODE_NEVER &&
bdrv_dirty_bitmap_check(sync_bitmap, BDRV_BITMAP_DEFAULT, errp)) {
return NULL;
}
/* Create a new bitmap, and freeze/disable this one. */
if (bdrv_dirty_bitmap_create_successor(sync_bitmap, errp) < 0) {
return NULL;
}
}
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
len = bdrv_getlength(bs);
if (len < 0) {
error_setg_errno(errp, -len, "Unable to get length for '%s'",
bdrv_get_device_or_node_name(bs));
goto error;
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
}
target_len = bdrv_getlength(target);
if (target_len < 0) {
error_setg_errno(errp, -target_len, "Unable to get length for '%s'",
bdrv_get_device_or_node_name(bs));
goto error;
}
if (target_len != len) {
error_setg(errp, "Source and target image have different sizes");
goto error;
}
cbw = bdrv_cbw_append(bs, target, filter_node_name, &bcs, errp);
block: rename backup-top to copy-before-write We are going to convert backup_top to full featured public filter, which can be used in separate of backup job. Start from renaming from "how it used" to "what it does". While updating comments in 283 iotest, drop and rephrase also things about ".active", as this field is now dropped, and filter doesn't have "inactive" mode. Note that this change may be considered as incompatible interface change, as backup-top filter format name was visible through query-block and query-named-block-nodes. Still, consider the following reasoning: 1. backup-top was never documented, so if someone depends on format name (for driver that can't be used other than it is automatically inserted on backup job start), it's a kind of "undocumented feature use". So I think we are free to change it. 2. There is a hope, that there is no such users: it's a lot more native to give a good node-name to backup-top filter if need to operate with it somehow, and don't touch format name. 3. Another "incompatible" change in further commit would be moving copy-before-write filter from using backing child to file child. And this is even more reasonable than renaming: for now all public filters are file-child based. So, it's a risky change, but risk seems small and good interface worth it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210824083856.17408-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2021-08-24 10:38:27 +02:00
if (!cbw) {
block/backup: use backup-top instead of write notifiers Drop write notifiers and use filter node instead. = Changes = 1. Add filter-node-name argument for backup qmp api. We have to do it in this commit, as 257 needs to be fixed. 2. There are no more write notifiers here, so is_write_notifier parameter is dropped from block-copy paths. 3. To sync with in-flight requests at job finish we now have drained removing of the filter, we don't need rw-lock. 4. Block-copy is now using BdrvChildren instead of BlockBackends 5. As backup-top owns these children, we also move block-copy state into backup-top's ownership. = Iotest changes = 56: op-blocker doesn't shoot now, as we set it on source, but then check on filter, when trying to start second backup. To keep the test we instead can catch another collision: both jobs will get 'drive0' job-id, as job-id parameter is unspecified. To prevent interleaving with file-posix locks (as they are dependent on config) let's use another target for second backup. Also, it's obvious now that we'd like to drop this op-blocker at all and add a test-case for two backups from one node (to different destinations) actually works. But not in these series. 141: Output changed: prepatch, "Node is in use" comes from bdrv_has_blk check inside qmp_blockdev_del. But we've dropped block-copy blk objects, so no more blk objects on source bs (job blk is on backup-top filter bs). New message is from op-blocker, which is the next check in qmp_blockdev_add. 257: The test wants to emulate guest write during backup. They should go to filter node, not to original source node, of course. Therefore we need to specify filter node name and use it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20191001131409.14202-6-vsementsov@virtuozzo.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-01 15:14:09 +02:00
goto error;
}
cluster_size = block_copy_cluster_size(bcs);
if (perf->max_chunk && perf->max_chunk < cluster_size) {
error_setg(errp, "Required max-chunk (%" PRIi64 ") is less than backup "
"cluster size (%" PRIi64 ")", perf->max_chunk, cluster_size);
goto error;
}
/* job->len is fixed, so we can't allow resize */
block: rename backup-top to copy-before-write We are going to convert backup_top to full featured public filter, which can be used in separate of backup job. Start from renaming from "how it used" to "what it does". While updating comments in 283 iotest, drop and rephrase also things about ".active", as this field is now dropped, and filter doesn't have "inactive" mode. Note that this change may be considered as incompatible interface change, as backup-top filter format name was visible through query-block and query-named-block-nodes. Still, consider the following reasoning: 1. backup-top was never documented, so if someone depends on format name (for driver that can't be used other than it is automatically inserted on backup job start), it's a kind of "undocumented feature use". So I think we are free to change it. 2. There is a hope, that there is no such users: it's a lot more native to give a good node-name to backup-top filter if need to operate with it somehow, and don't touch format name. 3. Another "incompatible" change in further commit would be moving copy-before-write filter from using backing child to file child. And this is even more reasonable than renaming: for now all public filters are file-child based. So, it's a risky change, but risk seems small and good interface worth it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210824083856.17408-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2021-08-24 10:38:27 +02:00
job = block_job_create(job_id, &backup_job_driver, txn, cbw,
block/backup: use backup-top instead of write notifiers Drop write notifiers and use filter node instead. = Changes = 1. Add filter-node-name argument for backup qmp api. We have to do it in this commit, as 257 needs to be fixed. 2. There are no more write notifiers here, so is_write_notifier parameter is dropped from block-copy paths. 3. To sync with in-flight requests at job finish we now have drained removing of the filter, we don't need rw-lock. 4. Block-copy is now using BdrvChildren instead of BlockBackends 5. As backup-top owns these children, we also move block-copy state into backup-top's ownership. = Iotest changes = 56: op-blocker doesn't shoot now, as we set it on source, but then check on filter, when trying to start second backup. To keep the test we instead can catch another collision: both jobs will get 'drive0' job-id, as job-id parameter is unspecified. To prevent interleaving with file-posix locks (as they are dependent on config) let's use another target for second backup. Also, it's obvious now that we'd like to drop this op-blocker at all and add a test-case for two backups from one node (to different destinations) actually works. But not in these series. 141: Output changed: prepatch, "Node is in use" comes from bdrv_has_blk check inside qmp_blockdev_del. But we've dropped block-copy blk objects, so no more blk objects on source bs (job blk is on backup-top filter bs). New message is from op-blocker, which is the next check in qmp_blockdev_add. 257: The test wants to emulate guest write during backup. They should go to filter node, not to original source node, of course. Therefore we need to specify filter node name and use it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20191001131409.14202-6-vsementsov@virtuozzo.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-01 15:14:09 +02:00
0, BLK_PERM_ALL,
speed, creation_flags, cb, opaque, errp);
if (!job) {
goto error;
}
block: rename backup-top to copy-before-write We are going to convert backup_top to full featured public filter, which can be used in separate of backup job. Start from renaming from "how it used" to "what it does". While updating comments in 283 iotest, drop and rephrase also things about ".active", as this field is now dropped, and filter doesn't have "inactive" mode. Note that this change may be considered as incompatible interface change, as backup-top filter format name was visible through query-block and query-named-block-nodes. Still, consider the following reasoning: 1. backup-top was never documented, so if someone depends on format name (for driver that can't be used other than it is automatically inserted on backup job start), it's a kind of "undocumented feature use". So I think we are free to change it. 2. There is a hope, that there is no such users: it's a lot more native to give a good node-name to backup-top filter if need to operate with it somehow, and don't touch format name. 3. Another "incompatible" change in further commit would be moving copy-before-write filter from using backing child to file child. And this is even more reasonable than renaming: for now all public filters are file-child based. So, it's a risky change, but risk seems small and good interface worth it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210824083856.17408-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2021-08-24 10:38:27 +02:00
job->cbw = cbw;
job->source_bs = bs;
job->target_bs = target;
job->on_source_error = on_source_error;
job->on_target_error = on_target_error;
job->sync_mode = sync_mode;
job->sync_bitmap = sync_bitmap;
job->bitmap_mode = bitmap_mode;
block/backup: use backup-top instead of write notifiers Drop write notifiers and use filter node instead. = Changes = 1. Add filter-node-name argument for backup qmp api. We have to do it in this commit, as 257 needs to be fixed. 2. There are no more write notifiers here, so is_write_notifier parameter is dropped from block-copy paths. 3. To sync with in-flight requests at job finish we now have drained removing of the filter, we don't need rw-lock. 4. Block-copy is now using BdrvChildren instead of BlockBackends 5. As backup-top owns these children, we also move block-copy state into backup-top's ownership. = Iotest changes = 56: op-blocker doesn't shoot now, as we set it on source, but then check on filter, when trying to start second backup. To keep the test we instead can catch another collision: both jobs will get 'drive0' job-id, as job-id parameter is unspecified. To prevent interleaving with file-posix locks (as they are dependent on config) let's use another target for second backup. Also, it's obvious now that we'd like to drop this op-blocker at all and add a test-case for two backups from one node (to different destinations) actually works. But not in these series. 141: Output changed: prepatch, "Node is in use" comes from bdrv_has_blk check inside qmp_blockdev_del. But we've dropped block-copy blk objects, so no more blk objects on source bs (job blk is on backup-top filter bs). New message is from op-blocker, which is the next check in qmp_blockdev_add. 257: The test wants to emulate guest write during backup. They should go to filter node, not to original source node, of course. Therefore we need to specify filter node name and use it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-id: 20191001131409.14202-6-vsementsov@virtuozzo.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-01 15:14:09 +02:00
job->bcs = bcs;
job->cluster_size = cluster_size;
job->len = len;
job->perf = *perf;
block/backup: avoid copying less than full target clusters During incremental backups, if the target has a cluster size that is larger than the backup cluster size and we are backing up to a target that cannot (for whichever reason) pull clusters up from a backing image, we may inadvertantly create unusable incremental backup images. For example: If the bitmap tracks changes at a 64KB granularity and we transmit 64KB of data at a time but the target uses a 128KB cluster size, it is possible that only half of a target cluster will be recognized as dirty by the backup block job. When the cluster is allocated on the target image but only half populated with data, we lose the ability to distinguish between zero padding and uninitialized data. This does not happen if the target image has a backing file that points to the last known good backup. Even if we have a backing file, though, it's likely going to be faster to just buffer the redundant data ourselves from the live image than fetching it from the backing file, so let's just always round up to the target granularity. The same logic applies to backup modes top, none, and full. Copying fractional clusters without the guarantee of COW is dangerous, but even if we can rely on COW, it's likely better to just re-copy the data. Reported-by: Fam Zheng <famz@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1456433911-24718-3-git-send-email-jsnow@redhat.com Signed-off-by: Jeff Cody <jcody@redhat.com>
2016-02-25 21:58:30 +01:00
block_copy_set_copy_opts(bcs, perf->use_copy_range, compress);
block_copy_set_progress_meter(bcs, &job->common.job.progress);
block_copy_set_speed(bcs, speed);
block: rename backup-top to copy-before-write We are going to convert backup_top to full featured public filter, which can be used in separate of backup job. Start from renaming from "how it used" to "what it does". While updating comments in 283 iotest, drop and rephrase also things about ".active", as this field is now dropped, and filter doesn't have "inactive" mode. Note that this change may be considered as incompatible interface change, as backup-top filter format name was visible through query-block and query-named-block-nodes. Still, consider the following reasoning: 1. backup-top was never documented, so if someone depends on format name (for driver that can't be used other than it is automatically inserted on backup job start), it's a kind of "undocumented feature use". So I think we are free to change it. 2. There is a hope, that there is no such users: it's a lot more native to give a good node-name to backup-top filter if need to operate with it somehow, and don't touch format name. 3. Another "incompatible" change in further commit would be moving copy-before-write filter from using backing child to file child. And this is even more reasonable than renaming: for now all public filters are file-child based. So, it's a risky change, but risk seems small and good interface worth it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210824083856.17408-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2021-08-24 10:38:27 +02:00
/* Required permissions are taken by copy-before-write filter target */
block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
&error_abort);
return &job->common;
error:
if (sync_bitmap) {
bdrv_reclaim_dirty_bitmap(sync_bitmap, NULL);
}
block: rename backup-top to copy-before-write We are going to convert backup_top to full featured public filter, which can be used in separate of backup job. Start from renaming from "how it used" to "what it does". While updating comments in 283 iotest, drop and rephrase also things about ".active", as this field is now dropped, and filter doesn't have "inactive" mode. Note that this change may be considered as incompatible interface change, as backup-top filter format name was visible through query-block and query-named-block-nodes. Still, consider the following reasoning: 1. backup-top was never documented, so if someone depends on format name (for driver that can't be used other than it is automatically inserted on backup job start), it's a kind of "undocumented feature use". So I think we are free to change it. 2. There is a hope, that there is no such users: it's a lot more native to give a good node-name to backup-top filter if need to operate with it somehow, and don't touch format name. 3. Another "incompatible" change in further commit would be moving copy-before-write filter from using backing child to file child. And this is even more reasonable than renaming: for now all public filters are file-child based. So, it's a risky change, but risk seems small and good interface worth it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210824083856.17408-6-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com>
2021-08-24 10:38:27 +02:00
if (cbw) {
bdrv_cbw_drop(cbw);
}
return NULL;
block: add basic backup support to block driver backup_start() creates a block job that copies a point-in-time snapshot of a block device to a target block device. We call backup_do_cow() for each write during backup. That function reads the original data from the block device before it gets overwritten. The data is then written to the target device. Currently backup cluster size is hardcoded to 65536 bytes. [I made a number of changes to Dietmar's original patch and folded them in to make code review easy. Here is the full list: * Drop BackupDumpFunc interface in favor of a target block device * Detect zero clusters with buffer_is_zero() and use bdrv_co_write_zeroes() * Use 0 delay instead of 1us, like other block jobs * Unify creation/start functions into backup_start() * Simplify cleanup, free bitmap in backup_run() instead of cb * function * Use HBitmap to avoid duplicating bitmap code * Use bdrv_getlength() instead of accessing ->total_sectors * directly * Delete the backup.h header file, it is no longer necessary * Move ./backup.c to block/backup.c * Remove #ifdefed out code * Coding style and whitespace cleanups * Use bdrv_add_before_write_notifier() instead of blockjob-specific hooks * Keep our own in-flight CowRequest list instead of using block.c tracked requests. This means a little code duplication but is much simpler than trying to share the tracked requests list and use the backup block size. * Add on_source_error and on_target_error error handling. * Use trace events instead of DPRINTF() -- stefanha] Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-06-24 17:13:11 +02:00
}