2019-10-01 21:14:08 +08:00
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/*
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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 16:38:27 +08:00
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* copy-before-write filter driver
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2019-10-01 21:14:08 +08:00
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*
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* The driver performs Copy-Before-Write (CBW) operation: it is injected above
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* some node, and before each write it copies _old_ data to the target node.
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*
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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 16:38:27 +08:00
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* Copyright (c) 2018-2021 Virtuozzo International GmbH.
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2019-10-01 21:14:08 +08:00
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*
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* Author:
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* Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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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 16:38:27 +08:00
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#ifndef COPY_BEFORE_WRITE_H
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#define COPY_BEFORE_WRITE_H
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2019-10-01 21:14:08 +08:00
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#include "block/block_int.h"
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#include "block/block-copy.h"
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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 16:38:27 +08:00
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BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
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BlockDriverState *target,
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const char *filter_node_name,
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BlockCopyState **bcs,
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Error **errp);
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void bdrv_cbw_drop(BlockDriverState *bs);
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2019-10-01 21:14:08 +08:00
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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 16:38:27 +08:00
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#endif /* COPY_BEFORE_WRITE_H */
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