block/block-backend.c | 8 ++ block/file-posix.c | 92 +++++++++++++++++++- block/io.c | 192 +++++++++++++++++++++++++++++++++++++++++ block/qcow2.c | 103 +++++++++++++++------- block/raw-format.c | 9 ++ include/block/block.h | 12 ++- include/block/block_int.h | 35 ++++++++ include/block/raw-aio.h | 10 ++- include/sysemu/block-backend.h | 4 + qemu-img.c | 45 +++++++++- 10 files changed, 472 insertions(+), 38 deletions(-)
[Posting a preview RFC for the general idea discussion and internal API review. Libiscsi support is being worked on in the meantime.] This series introduces block layer API for copy offloading and makes use of it in qemu-img convert. For now we implemented the operation in local file protocol with copy_file_range(2). Besides that it's possible to add similar to iscsi, nfs and potentially more. As far as its usage goes, in addition to qemu-img convert, we can emulate offloading in scsi-disk (EXTENDED COPY), and do similar to drive-mirror. The new bdrv_co_map_range can also be an alternative way to implement format drivers in the future, once we make block/io.c use it in preadv/pwritev paths. Fam Zheng (8): block: Introduce bdrv_co_map_range API qcow2: Implement bdrv_co_map_range block: Introduce bdrv_co_copy_range file-posix: Implement bdrv_co_copy_range file-posix: Implement bdrv_co_map_range raw: Implement raw_co_map_range block-backend: Add blk_co_copy_range qemu-img: Convert with copy offloading block/block-backend.c | 8 ++ block/file-posix.c | 92 +++++++++++++++++++- block/io.c | 192 +++++++++++++++++++++++++++++++++++++++++ block/qcow2.c | 103 +++++++++++++++------- block/raw-format.c | 9 ++ include/block/block.h | 12 ++- include/block/block_int.h | 35 ++++++++ include/block/raw-aio.h | 10 ++- include/sysemu/block-backend.h | 4 + qemu-img.c | 45 +++++++++- 10 files changed, 472 insertions(+), 38 deletions(-) -- 2.14.3
Hi, This series failed docker-build@min-glib build test. Please find the testing commands and their output below. If you have Docker installed, you can probably reproduce it locally. Type: series Message-id: 20180329110914.20888-1-famz@redhat.com Subject: [Qemu-devel] [RFC PATCH 0/8] qemu-img convert with copy offloading === TEST SCRIPT BEGIN === #!/bin/bash set -e git submodule update --init dtc # Let docker tests dump environment info export SHOW_ENV=1 export J=8 time make docker-test-build@min-glib === TEST SCRIPT END === Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384 Switched to a new branch 'test' 6f3b33fe62 qemu-img: Convert with copy offloading b435388660 block-backend: Add blk_co_copy_range 388616cd3c raw: Implement raw_co_map_range a4e47507b4 file-posix: Implement bdrv_co_map_range 8a6e25ecab file-posix: Implement bdrv_co_copy_range a3a1a163e2 block: Introduce bdrv_co_copy_range b42ec41133 qcow2: Implement bdrv_co_map_range 1eadcd710a block: Introduce bdrv_co_map_range API === OUTPUT BEGIN === Submodule 'dtc' (git://git.qemu-project.org/dtc.git) registered for path 'dtc' Cloning into '/var/tmp/patchew-tester-tmp-mfpmh0ne/src/dtc'... Submodule path 'dtc': checked out 'e54388015af1fb4bf04d0bca99caba1074d9cc42' BUILD min-glib make[1]: Entering directory '/var/tmp/patchew-tester-tmp-mfpmh0ne/src' GEN /var/tmp/patchew-tester-tmp-mfpmh0ne/src/docker-src.2018-03-31-04.12.45.21136/qemu.tar Cloning into '/var/tmp/patchew-tester-tmp-mfpmh0ne/src/docker-src.2018-03-31-04.12.45.21136/qemu.tar.vroot'... done. 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Your branch is up-to-date with 'origin/test'. Submodule 'dtc' (git://git.qemu-project.org/dtc.git) registered for path 'dtc' Cloning into '/var/tmp/patchew-tester-tmp-mfpmh0ne/src/docker-src.2018-03-31-04.12.45.21136/qemu.tar.vroot/dtc'... Submodule path 'dtc': checked out 'e54388015af1fb4bf04d0bca99caba1074d9cc42' Submodule 'ui/keycodemapdb' (git://git.qemu.org/keycodemapdb.git) registered for path 'ui/keycodemapdb' Cloning into '/var/tmp/patchew-tester-tmp-mfpmh0ne/src/docker-src.2018-03-31-04.12.45.21136/qemu.tar.vroot/ui/keycodemapdb'... Submodule path 'ui/keycodemapdb': checked out '6b3d716e2b6472eb7189d3220552280ef3d832ce' tar: /var/tmp/patchew-tester-tmp-mfpmh0ne/src/docker-src.2018-03-31-04.12.45.21136/qemu.tar: Wrote only 2048 of 10240 bytes tar: Error is not recoverable: exiting now failed to create tar file COPY RUNNER RUN test-build in qemu:min-glib tar: Unexpected EOF in archive tar: Unexpected EOF in archive tar: Error is not recoverable: exiting now /var/tmp/qemu/run: line 32: prep_fail: command not found Environment variables: HOSTNAME=a38ba0cc2dc5 MAKEFLAGS= -j8 J=8 CCACHE_DIR=/var/tmp/ccache EXTRA_CONFIGURE_OPTS= V= SHOW_ENV=1 PATH=/usr/lib/ccache:/usr/lib64/ccache:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin PWD=/ TARGET_LIST= SHLVL=1 HOME=/root TEST_DIR=/tmp/qemu-test FEATURES= dtc DEBUG= _=/usr/bin/env /var/tmp/qemu/run: line 52: cd: /tmp/qemu-test/src/tests/docker: No such file or directory /var/tmp/qemu/run: line 57: /test-build: No such file or directory /var/tmp/qemu/run: line 57: exec: /test-build: cannot execute: No such file or directory Traceback (most recent call last): File "./tests/docker/docker.py", line 407, in <module> sys.exit(main()) File "./tests/docker/docker.py", line 404, in main return args.cmdobj.run(args, argv) File "./tests/docker/docker.py", line 261, in run return Docker().run(argv, args.keep, quiet=args.quiet) File "./tests/docker/docker.py", line 229, in run quiet=quiet) File "./tests/docker/docker.py", line 147, in _do_check return subprocess.check_call(self._command + cmd, **kwargs) File "/usr/lib64/python2.7/subprocess.py", line 186, in check_call raise CalledProcessError(retcode, cmd) subprocess.CalledProcessError: Command '['docker', 'run', '--label', 'com.qemu.instance.uuid=5970da9034bb11e8a39d52540069c830', '-u', '0', '--security-opt', 'seccomp=unconfined', '--rm', '--net=none', '-e', 'TARGET_LIST=', '-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=8', '-e', 'DEBUG=', '-e', 'SHOW_ENV=1', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v', '/root/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v', '/var/tmp/patchew-tester-tmp-mfpmh0ne/src/docker-src.2018-03-31-04.12.45.21136:/var/tmp/qemu:z,ro', 'qemu:min-glib', '/var/tmp/qemu/run', 'test-build']' returned non-zero exit status 126 make[1]: *** [tests/docker/Makefile.include:129: docker-run] Error 1 make[1]: Leaving directory '/var/tmp/patchew-tester-tmp-mfpmh0ne/src' make: *** [tests/docker/Makefile.include:163: docker-run-test-build@min-glib] Error 2 real 0m38.034s user 0m9.304s sys 0m6.995s === OUTPUT END === Test command exited with code: 2 --- Email generated automatically by Patchew [http://patchew.org/]. Please send your feedback to patchew-devel@redhat.com
On Thu, Mar 29, 2018 at 07:09:06PM +0800, Fam Zheng wrote: > [Posting a preview RFC for the general idea discussion and internal API review. > Libiscsi support is being worked on in the meantime.] > > This series introduces block layer API for copy offloading and makes use of it > in qemu-img convert. > > For now we implemented the operation in local file protocol with > copy_file_range(2). Besides that it's possible to add similar to iscsi, nfs > and potentially more. > > As far as its usage goes, in addition to qemu-img convert, we can emulate > offloading in scsi-disk (EXTENDED COPY), and do similar to drive-mirror. > > The new bdrv_co_map_range can also be an alternative way to implement format > drivers in the future, once we make block/io.c use it in preadv/pwritev paths. I posted concerns about the bdrv_co_map_range() interface. It would be safer to only have a copy_range() interface without exposing how data is mapped outside the driver where race conditions can occur and the format driver no longer has full control over file layout. Stefan
On Wed, 04/04 14:23, Stefan Hajnoczi wrote: > On Thu, Mar 29, 2018 at 07:09:06PM +0800, Fam Zheng wrote: > > [Posting a preview RFC for the general idea discussion and internal API review. > > Libiscsi support is being worked on in the meantime.] > > > > This series introduces block layer API for copy offloading and makes use of it > > in qemu-img convert. > > > > For now we implemented the operation in local file protocol with > > copy_file_range(2). Besides that it's possible to add similar to iscsi, nfs > > and potentially more. > > > > As far as its usage goes, in addition to qemu-img convert, we can emulate > > offloading in scsi-disk (EXTENDED COPY), and do similar to drive-mirror. > > > > The new bdrv_co_map_range can also be an alternative way to implement format > > drivers in the future, once we make block/io.c use it in preadv/pwritev paths. > > I posted concerns about the bdrv_co_map_range() interface. It would be > safer to only have a copy_range() interface without exposing how data is > mapped outside the driver where race conditions can occur and the format > driver no longer has full control over file layout. It's a good point, but I couldn't think of a way to implement copy_range between two format drivers: both of them need to recurse down to their bs->file and what we eventually want is a copy_file_range() on two fds (or an iscsi equivalent): src[qcow2] -> dst[raw] | | v v src[file] -> dst[file] | | v v fd1 -> fd2 copy_file_range Maybe we should add BlockDriver.bdrv_co_map_range_{prepare,commit,abort} and call them from bdrv_co_copy_range(). This way the code path works pretty much the same way to .bdrv_co_preadv/pwritev. Fam
On 04/04/2018 15:49, Fam Zheng wrote: >> I posted concerns about the bdrv_co_map_range() interface. It would be >> safer to only have a copy_range() interface without exposing how data is >> mapped outside the driver where race conditions can occur and the format >> driver no longer has full control over file layout. > It's a good point, but I couldn't think of a way to implement copy_range between > two format drivers: both of them need to recurse down to their bs->file and what > we eventually want is a copy_file_range() on two fds (or an iscsi equivalent): > > src[qcow2] -> dst[raw] > | | > v v > src[file] -> dst[file] > | | > v v > fd1 -> fd2 > copy_file_range > > Maybe we should add BlockDriver.bdrv_co_map_range_{prepare,commit,abort} and > call them from bdrv_co_copy_range(). This way the code path works pretty much > the same way to .bdrv_co_preadv/pwritev. Or you could have bdrv_co_copy_range verify the mapping and return -EAGAIN if it is not valid anymore? (Then bdrv_co_map_range should fill in a BlockDriverMapping struct, or something like that). Paolo
On Wed, Apr 04, 2018 at 09:49:23PM +0800, Fam Zheng wrote: > On Wed, 04/04 14:23, Stefan Hajnoczi wrote: > > On Thu, Mar 29, 2018 at 07:09:06PM +0800, Fam Zheng wrote: > > > [Posting a preview RFC for the general idea discussion and internal API review. > > > Libiscsi support is being worked on in the meantime.] > > > > > > This series introduces block layer API for copy offloading and makes use of it > > > in qemu-img convert. > > > > > > For now we implemented the operation in local file protocol with > > > copy_file_range(2). Besides that it's possible to add similar to iscsi, nfs > > > and potentially more. > > > > > > As far as its usage goes, in addition to qemu-img convert, we can emulate > > > offloading in scsi-disk (EXTENDED COPY), and do similar to drive-mirror. > > > > > > The new bdrv_co_map_range can also be an alternative way to implement format > > > drivers in the future, once we make block/io.c use it in preadv/pwritev paths. > > > > I posted concerns about the bdrv_co_map_range() interface. It would be > > safer to only have a copy_range() interface without exposing how data is > > mapped outside the driver where race conditions can occur and the format > > driver no longer has full control over file layout. > > It's a good point, but I couldn't think of a way to implement copy_range between > two format drivers: both of them need to recurse down to their bs->file and what > we eventually want is a copy_file_range() on two fds (or an iscsi equivalent): > > src[qcow2] -> dst[raw] > | | > v v > src[file] -> dst[file] > | | > v v > fd1 -> fd2 > copy_file_range > > Maybe we should add BlockDriver.bdrv_co_map_range_{prepare,commit,abort} and > call them from bdrv_co_copy_range(). This way the code path works pretty much > the same way to .bdrv_co_preadv/pwritev. Regarding the recursion, there are two phases: 1. Finding the leaf BDS of the source (the left side of your diagram) 2. finding the leaf BDS of the destination (the right side) Here is one way to represent this in BlockDriver: /* Map [offset, offset + nbytes) range onto a child of src_bs and * invoke bdrv_co_copy_file_range_src(child, ...), or invoke * bdrv_co_copy_file_range_dst() if the leaf child has been found. */ .bdrv_co_copy_file_range_src(src_bs, dst_bs, offset, nbytes) /* Map [offset, offset + nbytes) range onto a child of dst_bs and * invoke bdrv_co_copy_file_range_src(src_bs, child, ...), or perform * the copy operation if the leaf child has been found. Return * -ENOTSUP if src_bs and the leaf child have different BlockDrivers. */ .bdrv_co_copy_file_range_dst(src_bs, dst_bs, offset, nbytes) bdrv_copy_file_range() will invoke bdrv_co_copy_file_range_src() on src[qcow2]. The qcow2 block driver will invoke bdrv_co_copy_file_range_src() on src[file]. The file-posix driver will invoke bdrv_co_copy_file_range_dst() on dst[raw]. The raw driver will invoke bdrv_co_copy_file_range_dst() on dst[file], which sees that src_bds (src[file]) is also file-posix and then goes ahead with copy_file_range(2). In the case where src[qcow2] is on file-posix but dst[raw] is on iSCSI, the iSCSI .bdrv_co_copy_file_range_dst() call fails with -ENOTSUP and the block layer can fall back to a traditional copy operation. With this approach src[qcow2] could take a lock or keep track of a serializing request struct so that other requests cannot interfere with the operation, and it's done in a natural way since we remain in the qcow2 function until the entire operation completes. There's no need for bookkeeping structs or callbacks. Stefan
On 05/04/2018 14:55, Stefan Hajnoczi wrote: > bdrv_copy_file_range() will invoke bdrv_co_copy_file_range_src() on > src[qcow2]. The qcow2 block driver will invoke > bdrv_co_copy_file_range_src() on src[file]. The file-posix driver will > invoke bdrv_co_copy_file_range_dst() on dst[raw]. The raw driver will > invoke bdrv_co_copy_file_range_dst() on dst[file], which sees that > src_bds (src[file]) is also file-posix and then goes ahead with > copy_file_range(2). > > In the case where src[qcow2] is on file-posix but dst[raw] is on iSCSI, > the iSCSI .bdrv_co_copy_file_range_dst() call fails with -ENOTSUP and > the block layer can fall back to a traditional copy operation. > > With this approach src[qcow2] could take a lock or keep track of a > serializing request struct so that other requests cannot interfere with > the operation, and it's done in a natural way since we remain in the > qcow2 function until the entire operation completes. There's no need > for bookkeeping structs or callbacks. Could there be AB-BA deadlock if the guest attempts a concurrent copy from A to B and from B to A? Paolo
On Fri, 04/06 13:41, Paolo Bonzini wrote: > On 05/04/2018 14:55, Stefan Hajnoczi wrote: > > bdrv_copy_file_range() will invoke bdrv_co_copy_file_range_src() on > > src[qcow2]. The qcow2 block driver will invoke > > bdrv_co_copy_file_range_src() on src[file]. The file-posix driver will > > invoke bdrv_co_copy_file_range_dst() on dst[raw]. The raw driver will > > invoke bdrv_co_copy_file_range_dst() on dst[file], which sees that > > src_bds (src[file]) is also file-posix and then goes ahead with > > copy_file_range(2). > > > > In the case where src[qcow2] is on file-posix but dst[raw] is on iSCSI, > > the iSCSI .bdrv_co_copy_file_range_dst() call fails with -ENOTSUP and > > the block layer can fall back to a traditional copy operation. > > > > With this approach src[qcow2] could take a lock or keep track of a > > serializing request struct so that other requests cannot interfere with > > the operation, and it's done in a natural way since we remain in the > > qcow2 function until the entire operation completes. There's no need > > for bookkeeping structs or callbacks. > > Could there be AB-BA deadlock if the guest attempts a concurrent copy > from A to B and from B to A? I don't think bs_src need to hold its locks when calling into bs_dst for mapping write ranges. So it should be safe. Fam
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