riscv/qemu - qemu - Gitea: Git with a cup of tea

Commit Graph

Author	SHA1	Message	Date
Stefan Hajnoczi	f4ec04bae9	block: return errors from bdrv_register_buf() Registering an I/O buffer is only a performance optimization hint but it is still necessary to return errors when it fails. Later patches will need to detect errors when registering buffers but an immediate advantage is that error_report() calls are no longer needed in block driver .bdrv_register_buf() functions. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20221013185908.1297568-8-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>	4 years ago
Stefan Hajnoczi	98b3ddc78b	block: use BdrvRequestFlags type for supported flag fields Use the enum type so GDB displays the enum members instead of printing a numeric constant. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20221013185908.1297568-6-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>	4 years ago
Stefan Hajnoczi	4f384011c5	block: pass size to bdrv_unregister_buf() The only implementor of bdrv_register_buf() is block/nvme.c, where the size is not needed when unregistering a buffer. This is because util/vfio-helpers.c can look up mappings by address. Future block drivers that implement bdrv_register_buf() may not be able to do their job given only the buffer address. Add a size argument to bdrv_unregister_buf(). Also document the assumptions about bdrv_register_buf()/bdrv_unregister_buf() calls. The same <host, size> values that were given to bdrv_register_buf() must be given to bdrv_unregister_buf(). gcc 11.2.1 emits a spurious warning that img_bench()'s buf_size local variable might be uninitialized, so it's necessary to silence the compiler. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20221013185908.1297568-5-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>	4 years ago
Vladimir Sementsov-Ogievskiy	1c14eaabdb	block: introduce snapshot-access block driver The new block driver simply utilizes snapshot-access API of underlying block node. In further patches we want to use it like this: [guest] [NBD export] \| \| \| root \| root v file v [copy-before-write]<------[snapshot-access] \| \| \| file \| target v v [active-disk] [temp.img] This way, NBD client will be able to read snapshotted state of active disk, when active disk is continued to be written by guest. This is known as "fleecing", and currently uses another scheme based on qcow2 temporary image which backing file is active-disk. New scheme comes with benefits - see next commit. The other possible application is exporting internal snapshots of qcow2, like this: [guest] [NBD export] \| \| \| root \| root v file v [qcow2]<---------[snapshot-access] For this, we'll need to implement snapshot-access API handlers in qcow2 driver, and improve snapshot-access block driver (and API) to make it possible to select snapshot by name. Another thing to improve is size of snapshot. Now for simplicity we just use size of bs->file, which is OK for backup, but for qcow2 snapshots export we'll need to imporve snapshot-access API to get size of snapshot. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20220303194349.2304213-12-vsementsov@virtuozzo.com> [hreitz: Rebased on block GS/IO split] Signed-off-by: Hanna Reitz <hreitz@redhat.com>	4 years ago
Vladimir Sementsov-Ogievskiy	ce14f3b407	block/io: introduce block driver snapshot-access API Add new block driver handlers and corresponding generic wrappers. It will be used to allow copy-before-write filter to provide reach fleecing interface in further commit. In future this approach may be used to allow reading qcow2 internal snapshots, for example to export them through NBD. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220303194349.2304213-11-vsementsov@virtuozzo.com> [hreitz: Rebased on block GS/IO split] Signed-off-by: Hanna Reitz <hreitz@redhat.com>	4 years ago
Emanuele Giuseppe Esposito	abc5a79c64	block_int-common.h: split function pointers in BdrvChildClass Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20220303151616.325444-28-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	4 years ago
Emanuele Giuseppe Esposito	69c0bf1197	block_int-common.h: split function pointers in BlockDriver Similar to the header split, also the function pointers in BlockDriver can be split in I/O and global state. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20220303151616.325444-26-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	4 years ago
Emanuele Giuseppe Esposito	ebc2752b08	include/block/block_int: split header into I/O and global state API Similarly to the previous patch, split block_int.h in block_int-io.h and block_int-global-state.h block_int-common.h contains the structures shared between the two headers, and the functions that can't be categorized as I/O or global state. Assertions are added in the next patch. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20220303151616.325444-12-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	4 years ago
Emanuele Giuseppe Esposito	c1019d1687	crypto: perform permission checks under BQL Move the permission API calls into driver-specific callbacks that always run under BQL. In this case, bdrv_crypto_luks needs to perform permission checks before and after qcrypto_block_amend_options(). The problem is that the caller, block_crypto_amend_options_generic_luks(), can also run in I/O from .bdrv_co_amend(). This does not comply with Global State-I/O API split, as permissions API must always run under BQL. Firstly, introduce .bdrv_amend_pre_run() and .bdrv_amend_clean() callbacks. These two callbacks are guaranteed to be invoked under BQL, respectively before and after .bdrv_co_amend(). They take care of performing the permission checks in the same way as they are currently done before and after qcrypto_block_amend_options(). These callbacks are in preparation for next patch, where we delete the original permission check. Right now they just add redundant control. Then, call .bdrv_amend_pre_run() before job_start in qmp_x_blockdev_amend(), so that it will be run before the job coroutine is created and stay in the main loop. As a cleanup, use JobDriver's .clean() callback to call .bdrv_amend_clean(), and run amend-specific cleanup callbacks under BQL. After this patch, permission failures occur early in the blockdev-amend job to update a LUKS volume's keys. iotest 296 must now expect them in x-blockdev-amend's QMP reply instead of waiting for the actual job to fail later. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20220209105452.1694545-2-eesposit@redhat.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20220304153729.711387-6-hreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	5 years ago
Emanuele Giuseppe Esposito	fa8fc1d09f	block_int: make bdrv_backing_overridden static bdrv_backing_overridden is only used in block.c, so there is no need to leave it in block_int.h Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20211215121140.456939-2-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	5 years ago
Paolo Bonzini	cc07162953	block: introduce max_hw_iov for use in scsi-generic Linux limits the size of iovecs to 1024 (UIO_MAXIOV in the kernel sources, IOV_MAX in POSIX). Because of this, on some host adapters requests with many iovecs are rejected with -EINVAL by the io_submit() or readv()/writev() system calls. In fact, the same limit applies to SG_IO as well. To fix both the EINVAL and the possible performance issues from using fewer iovecs than allowed by Linux (some HBAs have max_segments as low as 128), introduce a separate entry in BlockLimits to hold the max_segments value from sysfs. This new limit is used only for SG_IO and clamped to bs->bl.max_iov anyway, just like max_hw_transfer is clamped to bs->bl.max_transfer. Reported-by: Halil Pasic <pasic@linux.ibm.com> Cc: Hanna Reitz <hreitz@redhat.com> Cc: Kevin Wolf <kwolf@redhat.com> Cc: qemu-block@nongnu.org Cc: qemu-stable@nongnu.org Fixes: `18473467d5` ("file-posix: try BLKSECTGET on block devices too, do not round to power of 2", 2021-06-25) Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20210923130436.1187591-1-pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	0c8022876f	block: use int64_t instead of int in driver discard handlers We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). So, convert driver discard handlers bytes parameter to int64_t. The only caller of all updated function is bdrv_co_pdiscard in block/io.c. It is already prepared to work with 64bit requests, but pass at most max(bs->bl.max_pdiscard, INT_MAX) to the driver. Let's look at all updated functions: blkdebug: all calculations are still OK, thanks to bdrv_check_qiov_request(). both rule_check and bdrv_co_pdiscard are 64bit blklogwrites: pass to blk_loc_writes_co_log which is 64bit blkreplay, copy-on-read, filter-compress: pass to bdrv_co_pdiscard, OK copy-before-write: pass to bdrv_co_pdiscard which is 64bit and to cbw_do_copy_before_write which is 64bit file-posix: one handler calls raw_account_discard() is 64bit and both handlers calls raw_do_pdiscard(). Update raw_do_pdiscard, which pass to RawPosixAIOData::aio_nbytes, which is 64bit (and calls raw_account_discard()) gluster: somehow, third argument of glfs_discard_async is size_t. Let's set max_pdiscard accordingly. iscsi: iscsi_allocmap_set_invalid is 64bit, !is_byte_request_lun_aligned is 64bit. list.num is uint32_t. Let's clarify max_pdiscard and pdiscard_alignment. mirror_top: pass to bdrv_mirror_top_do_write() which is 64bit nbd: protocol limitation. max_pdiscard is alredy set strict enough, keep it as is for now. nvme: buf.nlb is uint32_t and we do shift. So, add corresponding limits to nvme_refresh_limits(). preallocate: pass to bdrv_co_pdiscard() which is 64bit. rbd: pass to qemu_rbd_start_co() which is 64bit. qcow2: calculations are still OK, thanks to bdrv_check_qiov_request(), qcow2_cluster_discard() is 64bit. raw-format: raw_adjust_offset() is 64bit, bdrv_co_pdiscard too. throttle: pass to bdrv_co_pdiscard() which is 64bit and to throttle_group_co_io_limits_intercept() which is 64bit as well. test-block-iothread: bytes argument is unused Great! Now all drivers are prepared to handle 64bit discard requests, or else have explicit max_pdiscard limits. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210903102807.27127-11-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	39af49c0d7	block: make BlockLimits::max_pdiscard 64bit We are going to support 64 bit discard requests. Now update the limit variable. It's absolutely safe. The variable is set in some drivers, and used in bdrv_co_pdiscard(). Update also max_pdiscard variable in bdrv_co_pdiscard(), so that bdrv_co_pdiscard() is now prepared for 64bit requests. The remaining logic including num, offset and bytes variables is already supporting 64bit requests. So the only thing that prevents 64 bit requests is limiting max_pdiscard variable to INT_MAX in bdrv_co_pdiscard(). We'll drop this limitation after updating all block drivers. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210903102807.27127-10-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	f34b2bcf8c	block: use int64_t instead of int in driver write_zeroes handlers We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). So, convert driver write_zeroes handlers bytes parameter to int64_t. The only caller of all updated function is bdrv_co_do_pwrite_zeroes(). bdrv_co_do_pwrite_zeroes() itself is of course OK with widening of callee parameter type. Also, bdrv_co_do_pwrite_zeroes()'s max_write_zeroes is limited to INT_MAX. So, updated functions all are safe, they will not get "bytes" larger than before. Still, let's look through all updated functions, and add assertions to the ones which are actually unprepared to values larger than INT_MAX. For these drivers also set explicit max_pwrite_zeroes limit. Let's go: blkdebug: calculations can't overflow, thanks to bdrv_check_qiov_request() in generic layer. rule_check() and bdrv_co_pwrite_zeroes() both have 64bit argument. blklogwrites: pass to blk_log_writes_co_log() with 64bit argument. blkreplay, copy-on-read, filter-compress: pass to bdrv_co_pwrite_zeroes() which is OK copy-before-write: Calls cbw_do_copy_before_write() and bdrv_co_pwrite_zeroes, both have 64bit argument. file-posix: both handler calls raw_do_pwrite_zeroes, which is updated. In raw_do_pwrite_zeroes() calculations are OK due to bdrv_check_qiov_request(), bytes go to RawPosixAIOData::aio_nbytes which is uint64_t. Check also where that uint64_t gets handed: handle_aiocb_write_zeroes_block() passes a uint64_t[2] to ioctl(BLKZEROOUT), handle_aiocb_write_zeroes() calls do_fallocate() which takes off_t (and we compile to always have 64-bit off_t), as does handle_aiocb_write_zeroes_unmap. All look safe. gluster: bytes go to GlusterAIOCB::size which is int64_t and to glfs_zerofill_async works with off_t. iscsi: Aha, here we deal with iscsi_writesame16_task() that has uint32_t num_blocks argument and iscsi_writesame16_task() has uint16_t argument. Make comments, add assertions and clarify max_pwrite_zeroes calculation. iscsi_allocmap_() functions already has int64_t argument is_byte_request_lun_aligned is simple to update, do it. mirror_top: pass to bdrv_mirror_top_do_write which has uint64_t argument nbd: Aha, here we have protocol limitation, and NBDRequest::len is uint32_t. max_pwrite_zeroes is cleanly set to 32bit value, so we are OK for now. nvme: Again, protocol limitation. And no inherent limit for write-zeroes at all. But from code that calculates cdw12 it's obvious that we do have limit and alignment. Let's clarify it. Also, obviously the code is not prepared to handle bytes=0. Let's handle this case too. trace events already 64bit preallocate: pass to handle_write() and bdrv_co_pwrite_zeroes(), both 64bit. rbd: pass to qemu_rbd_start_co() which is 64bit. qcow2: offset + bytes and alignment still works good (thanks to bdrv_check_qiov_request()), so tail calculation is OK qcow2_subcluster_zeroize() has 64bit argument, should be OK trace events updated qed: qed_co_request wants int nb_sectors. Also in code we have size_t used for request length which may be 32bit. So, let's just keep INT_MAX as a limit (aligning it down to pwrite_zeroes_alignment) and don't care. raw-format: Is OK. raw_adjust_offset and bdrv_co_pwrite_zeroes are both 64bit. throttle: Both throttle_group_co_io_limits_intercept() and bdrv_co_pwrite_zeroes() are 64bit. vmdk: pass to vmdk_pwritev which is 64bit quorum: pass to quorum_co_pwritev() which is 64bit Hooray! At this point all block drivers are prepared to support 64bit write-zero requests, or have explicitly set max_pwrite_zeroes. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210903102807.27127-8-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: use <= rather than < in assertions relying on max_pwrite_zeroes] Signed-off-by: Eric Blake <eblake@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	d544f5d3b1	block: make BlockLimits::max_pwrite_zeroes 64bit We are going to support 64 bit write-zeroes requests. Now update the limit variable. It's absolutely safe. The variable is set in some drivers, and used in bdrv_co_do_pwrite_zeroes(). Update also max_write_zeroes variable in bdrv_co_do_pwrite_zeroes(), so that bdrv_co_do_pwrite_zeroes() is now prepared to 64bit requests. The remaining logic including num, offset and bytes variables is already supporting 64bit requests. So the only thing that prevents 64 bit requests is limiting max_write_zeroes variable to INT_MAX in bdrv_co_do_pwrite_zeroes(). We'll drop this limitation after updating all block drivers. Ah, we also have bdrv_check_request32() in bdrv_co_pwritev_part(). It will be modified to do bdrv_check_request() for write-zeroes path. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210903102807.27127-7-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	485350497b	block: use int64_t instead of uint64_t in copy_range driver handlers We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). So, convert driver copy_range handlers parameters which are already 64bit to signed type. Now let's consider all callers. Simple git grep '\->bdrv_co_copy_range' shows the only caller: bdrv_co_copy_range_internal(), which does bdrv_check_request32(), so everything is OK. Still, the functions may be called directly, not only by drv->... Let's check: git grep '\.bdrv_co_copy_range_$from\\|to$\s*=' \| \ awk '{print $4}' \| sed 's/,//' \| sed 's/&//' \| sort \| uniq \| \ while read func; do git grep "$func(" \| \ grep -v "$func(BlockDriverState"; done shows no more callers. So, we are done. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210903102807.27127-6-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	e75abedab7	block: use int64_t instead of uint64_t in driver write handlers We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). So, convert driver write handlers parameters which are already 64bit to signed type. While being here, convert also flags parameter to be BdrvRequestFlags. Now let's consider all callers. Simple git grep '\->bdrv_$aio\\|co$_pwritev$_part$\?' shows that's there three callers of driver function: bdrv_driver_pwritev() and bdrv_driver_pwritev_compressed() in block/io.c, both pass int64_t, checked by bdrv_check_qiov_request() to be non-negative. qcow2_save_vmstate() does bdrv_check_qiov_request(). Still, the functions may be called directly, not only by drv->... Let's check: git grep '\.bdrv_$aio\\|co$_pwritev$_part$\?\s*=' \| \ awk '{print $4}' \| sed 's/,//' \| sed 's/&//' \| sort \| uniq \| \ while read func; do git grep "$func(" \| \ grep -v "$func(BlockDriverState"; done shows several callers: qcow2: qcow2_co_truncate() write at most up to @offset, which is checked in generic qcow2_co_truncate() by bdrv_check_request(). qcow2_co_pwritev_compressed_task() pass the request (or part of the request) that already went through normal write path, so it should be OK qcow: qcow_co_pwritev_compressed() pass int64_t, it's updated by this patch quorum: quorum_co_pwrite_zeroes() pass int64_t and int - OK throttle: throttle_co_pwritev_compressed() pass int64_t, it's updated by this patch vmdk: vmdk_co_pwritev_compressed() pass int64_t, it's updated by this patch Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210903102807.27127-5-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	f7ef38dd13	block: use int64_t instead of uint64_t in driver read handlers We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). So, convert driver read handlers parameters which are already 64bit to signed type. While being here, convert also flags parameter to be BdrvRequestFlags. Now let's consider all callers. Simple git grep '\->bdrv_$aio\\|co$_preadv$_part$\?' shows that's there three callers of driver function: bdrv_driver_preadv() in block/io.c, passes int64_t, checked by bdrv_check_qiov_request() to be non-negative. qcow2_load_vmstate() does bdrv_check_qiov_request(). do_perform_cow_read() has uint64_t argument. And a lot of things in qcow2 driver are uint64_t, so converting it is big job. But we must not work with requests that don't satisfy bdrv_check_qiov_request(), so let's just assert it here. Still, the functions may be called directly, not only by drv->... Let's check: git grep '\.bdrv_$aio\\|co$_preadv$_part$\?\s*=' \| \ awk '{print $4}' \| sed 's/,//' \| sed 's/&//' \| sort \| uniq \| \ while read func; do git grep "$func(" \| \ grep -v "$func(BlockDriverState"; done The only one such caller: QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, &data, 1); ... ret = bdrv_replace_test_co_preadv(bs, 0, 1, &qiov, 0); in tests/unit/test-bdrv-drain.c, and it's OK obviously. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210903102807.27127-4-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: fix typos] Signed-off-by: Eric Blake <eblake@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	558902cc3d	qcow2: check request on vmstate save/load path We modify the request by adding an offset to vmstate. Let's check the modified request. It will help us to safely move .bdrv_co_preadv_part and .bdrv_co_pwritev_part to int64_t type of offset and bytes. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210903102807.27127-3-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>	5 years ago
Hanna Reitz	5a1cfd2150	block: Clarify that @bytes is no limit on pnum .bdrv_co_block_status() implementations are free to return a pnum that exceeds @bytes, because bdrv_co_block_status() in block/io.c will clamp pnum as necessary. On the other hand, if drivers' implementations return values for pnum that are as large as possible, our recently introduced block-status cache will become more effective. So, make a note in block_int.h that @bytes is no upper limit for *pnum. Suggested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Hanna Reitz <hreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210812084148.14458-4-hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>	5 years ago
Hanna Reitz	0bc329fbb0	block: block-status cache for data regions As we have attempted before (https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg06451.html, "file-posix: Cache lseek result for data regions"; https://lists.nongnu.org/archive/html/qemu-block/2021-02/msg00934.html, "file-posix: Cache next hole"), this patch seeks to reduce the number of SEEK_DATA/HOLE operations the file-posix driver has to perform. The main difference is that this time it is implemented as part of the general block layer code. The problem we face is that on some filesystems or in some circumstances, SEEK_DATA/HOLE is unreasonably slow. Given the implementation is outside of qemu, there is little we can do about its performance. We have already introduced the want_zero parameter to bdrv_co_block_status() to reduce the number of SEEK_DATA/HOLE calls unless we really want zero information; but sometimes we do want that information, because for files that consist largely of zero areas, special-casing those areas can give large performance boosts. So the real problem is with files that consist largely of data, so that inquiring the block status does not gain us much performance, but where such an inquiry itself takes a lot of time. To address this, we want to cache data regions. Most of the time, when bad performance is reported, it is in places where the image is iterated over from start to end (qemu-img convert or the mirror job), so a simple yet effective solution is to cache only the current data region. (Note that only caching data regions but not zero regions means that returning false information from the cache is not catastrophic: Treating zeroes as data is fine. While we try to invalidate the cache on zero writes and discards, such incongruences may still occur when there are other processes writing to the image.) We only use the cache for nodes without children (i.e. protocol nodes), because that is where the problem is: Drivers that rely on block-status implementations outside of qemu (e.g. SEEK_DATA/HOLE). Resolves: https://gitlab.com/qemu-project/qemu/-/issues/307 Signed-off-by: Hanna Reitz <hreitz@redhat.com> Message-Id: <20210812084148.14458-3-hreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [hreitz: Added `local_file == bs` assertion, as suggested by Vladimir] Signed-off-by: Hanna Reitz <hreitz@redhat.com>	5 years ago
Hanna Reitz	33ff4c9e08	block: Drop BDS comment regarding bdrv_append() There is a comment above the BDS definition stating care must be taken to consider handling newly added fields in bdrv_append(). Actually, this comment should have said "bdrv_swap()" as of `4ddc07cac` (nine years ago), and in any case, bdrv_swap() was dropped in `8e419aefa` (six years ago). So no such care is necessary anymore. 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: <20210812084148.14458-2-hreitz@redhat.com>	5 years ago
Paolo Bonzini	24b36e9813	block: add max_hw_transfer to BlockLimits For block host devices, I/O can happen through either the kernel file descriptor I/O system calls (preadv/pwritev, io_submit, io_uring) or the SCSI passthrough ioctl SG_IO. In the latter case, the size of each transfer can be limited by the HBA, while for file descriptor I/O the kernel is able to split and merge I/O in smaller pieces as needed. Applying the HBA limits to file descriptor I/O results in more system calls and suboptimal performance, so this patch splits the max_transfer limit in two: max_transfer remains valid and is used in general, while max_hw_transfer is limited to the maximum hardware size. max_hw_transfer can then be included by the scsi-generic driver in the block limits page, to ensure that the stricter hardware limit is used. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	260242a833	block: drop BlockBackendRootState::read_only Instead of keeping additional boolean field, let's store the information in BDRV_O_RDWR bit of BlockBackendRootState::open_flags. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210527154056.70294-4-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	975da07374	block: drop BlockDriverState::read_only This variable is just a cache for !(bs->open_flags & BDRV_O_RDWR), which we have to synchronize everywhere. Let's just drop it and consistently use bdrv_is_read_only(). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210527154056.70294-3-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	ad578c56d5	block: drop write notifiers They are unused now. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210506090621.11848-3-vsementsov@virtuozzo.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	94783301b8	block/write-threshold: don't use write notifiers write-notifiers are used only for write-threshold. New code for such purpose should create filters. Let's better special-case write-threshold and drop write notifiers at all. (Actually, write-threshold is special-cased anyway, as the only user of write-notifiers) So, create a new direct interface for bdrv_co_write_req_prepare() and drop all write-notifier related logic from write-threshold.c. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210506090621.11848-2-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> [mreitz: Adjusted comment as per Eric's suggestion] Signed-off-by: Max Reitz <mreitz@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	9c785cd714	mirror: stop cancelling in-flight requests on non-force cancel in READY If mirror is READY than cancel operation is not discarding the whole result of the operation, but instead it's a documented way get a point-in-time snapshot of source disk. So, we should not cancel any requests if mirror is READ and force=false. Let's fix that case. Note, that bug that we have before this commit is not critical, as the only .bdrv_cancel_in_flight implementation is nbd_cancel_in_flight() and it cancels only requests waiting for reconnection, so it should be rare case. Fixes: `521ff8b779` Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20210421075858.40197-1-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	ecb776bd93	block: refactor bdrv_child_set_perm_safe() transaction action Old interfaces dropped, nobody directly calls bdrv_child_set_perm_abort() and bdrv_child_set_perm_commit(), so we can use personal state structure for the action and stop exploiting BdrvChild structure. Also, drop "_safe" suffix which is redundant now. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-35-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	228ca37e12	block: drop ctx argument from bdrv_root_attach_child Passing parent aio context is redundant, as child_class and parent opaque pointer are enough to retrieve it. Drop the argument and use new bdrv_child_get_parent_aio_context() interface. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-7-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	3ca1f32257	block: BdrvChildClass: add .get_parent_aio_context handler Add new handler to get aio context and implement it in all child classes. Add corresponding public interface to be used soon. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-6-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	5 years ago
Vladimir Sementsov-Ogievskiy	bd54669a4a	block: add new BlockDriver handler: bdrv_cancel_in_flight It will be used to stop retrying NBD requests on mirror cancel. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210205163720.887197-2-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>	6 years ago
Vladimir Sementsov-Ogievskiy	a5215b8fdf	block/io: use int64_t bytes in copy_range We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). So, convert now copy_range parameters which are already 64bit to signed type. It's safe as we don't work with requests overflowing BDRV_MAX_LENGTH (which is less than INT64_MAX), and do check the requests in bdrv_co_copy_range_internal() (by bdrv_check_request32(), which calls bdrv_check_request()). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201211183934.169161-17-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>	6 years ago
Vladimir Sementsov-Ogievskiy	e9e52efdc5	block/io: support int64_t bytes in read/write wrappers We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). Now, since bdrv_co_preadv_part() and bdrv_co_pwritev_part() have been updated, update all their wrappers. For all of them type of 'bytes' is widening, so callers are safe. We have update request_fn in blkverify.c simultaneously. Still it's just a pointer to one of bdrv_co_pwritev() or bdrv_co_preadv(), and type is widening for callers of the request_fn anyway. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201211183934.169161-16-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: grammar tweak] Signed-off-by: Eric Blake <eblake@redhat.com>	6 years ago
Vladimir Sementsov-Ogievskiy	37e9403ea8	block/io: support int64_t bytes in bdrv_co_p{read,write}v_part() We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). So, prepare bdrv_co_preadv_part() and bdrv_co_pwritev_part() and their remaining dependencies now. bdrv_pad_request() is updated simultaneously, as pointer to bytes passed to it both from bdrv_co_pwritev_part() and bdrv_co_preadv_part(). So, all callers of bdrv_pad_request() are updated to pass 64bit bytes. bdrv_pad_request() is already good for 64bit requests, add corresponding assertion. Look at bdrv_co_preadv_part() and bdrv_co_pwritev_part(). Type is widening, so callers are safe. Let's look inside the functions. In bdrv_co_preadv_part() and bdrv_aligned_pwritev() we only pass bytes to other already int64_t interfaces (and some obviously safe calculations), it's OK. In bdrv_co_do_zero_pwritev() aligned_bytes may become large now, still it's passed to bdrv_aligned_pwritev which supports int64_t bytes. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201211183934.169161-15-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>	6 years ago
Eric Blake	8024726459	block: use int64_t as bytes type in tracked requests We are generally moving to int64_t for both offset and bytes parameters on all io paths. Main motivation is realization of 64-bit write_zeroes operation for fast zeroing large disk chunks, up to the whole disk. We chose signed type, to be consistent with off_t (which is signed) and with possibility for signed return type (where negative value means error). All requests in block/io must not overflow BDRV_MAX_LENGTH, all external users of BdrvTrackedRequest already have corresponding assertions, so we are safe. Add some assertions still. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201211183934.169161-9-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>	6 years ago
Vladimir Sementsov-Ogievskiy	69b55e03f7	block: refactor bdrv_check_request: add errp It's better to pass &error_abort than just assert that result is 0: on crash, we'll immediately see the reason in the backtrace. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201211183934.169161-2-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> [eblake: fix iotest 206 fallout] Signed-off-by: Eric Blake <eblake@redhat.com>	6 years ago
Vladimir Sementsov-Ogievskiy	86c6a3b690	qapi: backup: add perf.use-copy-range parameter Experiments show, that copy_range is not always making things faster. So, to make experimentation simpler, let's add a parameter. Some more perf parameters will be added soon, so here is a new struct. For now, add new backup qmp parameter with x- prefix for the following reasons: - We are going to add more performance parameters, some will be related to the whole block-copy process, some only to background copying in backup (ignored for copy-before-write operations). - On the other hand, we are going to use block-copy interface in other block jobs, which will need performance options as well.. And it should be the same structure or at least somehow related. So, there are too much unclean things about how the interface and now we need the new options mostly for testing. Let's keep them experimental for a while. In do_backup_common() new x-perf parameter handled in a way to make further options addition simpler. We add use-copy-range with default=true, and we'll change the default in further patch, after moving backup to use block-copy. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210116214705.822267-2-vsementsov@virtuozzo.com> [mreitz: s/5\.2/6.0/] Signed-off-by: Max Reitz <mreitz@redhat.com>	6 years ago
Vladimir Sementsov-Ogievskiy	7f4a396d76	qapi: block-stream: add "bottom" argument The code already don't freeze base node and we try to make it prepared for the situation when base node is changed during the operation. In other words, block-stream doesn't own base node. Let's introduce a new interface which should replace the current one, which will in better relations with the code. Specifying bottom node instead of base, and requiring it to be non-filter gives us the following benefits: - drop difference between above_base and base_overlay, which will be renamed to just bottom, when old interface dropped - clean way to work with parallel streams/commits on the same backing chain, which otherwise become a problem when we introduce a filter for stream job - cleaner interface. Nobody will surprised the fact that base node may disappear during block-stream, when there is no word about "base" in the interface. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201216061703.70908-11-vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>	6 years ago
Andrey Shinkevich	897dd0ec4f	block: include supported_read_flags into BDS structure Add the new member supported_read_flags to the BlockDriverState structure. It will control the flags set for copy-on-read operations. Make the block generic layer evaluate supported read flags before they go to a block driver. Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [vsementsov: use assert instead of abort] Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20201216061703.70908-8-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>	6 years ago
Andrey Shinkevich	880747a887	qapi: add filter-node-name to block-stream Provide the possibility to pass the 'filter-node-name' parameter to the block-stream job as it is done for the commit block job. Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> [vsementsov: comment indentation, s/Since: 5.2/Since: 6.0/] Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20201216061703.70908-5-vsementsov@virtuozzo.com> [mreitz: s/commit/stream/] Signed-off-by: Max Reitz <mreitz@redhat.com>	6 years ago
Vladimir Sementsov-Ogievskiy	8ac5aab255	block: bdrv_mark_request_serialising: split non-waiting function We'll need a separate function, which will only "mark" request serialising with specified align but not wait for conflicting requests. So, it will be like old bdrv_mark_request_serialising(), before merging bdrv_wait_serialising_requests_locked() into it. To reduce the possible mess, let's do the following: Public function that does both marking and waiting will be called bdrv_make_request_serialising, and private function which will only "mark" will be called tracked_request_set_serialising(). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20201021145859.11201-6-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>	6 years ago
Vladimir Sementsov-Ogievskiy	8b1170012b	block: introduce BDRV_MAX_LENGTH We are going to modify block layer to work with 64bit requests. And first step is moving to int64_t type for both offset and bytes arguments in all block request related functions. It's mostly safe (when widening signed or unsigned int to int64_t), but switching from uint64_t is questionable. So, let's first establish the set of requests we want to work with. First signed int64_t should be enough, as off_t is signed anyway. Then, obviously offset + bytes should not overflow. And most interesting: (offset + bytes) being aligned up should not overflow as well. Aligned to what alignment? First thing that comes in mind is bs->bl.request_alignment, as we align up request to this alignment. But there is another thing: look at bdrv_mark_request_serialising(). It aligns request up to some given alignment. And this parameter may be bdrv_get_cluster_size(), which is often a lot greater than bs->bl.request_alignment. Note also, that bdrv_mark_request_serialising() uses signed int64_t for calculations. So, actually, we already depend on some restrictions. Happily, bdrv_get_cluster_size() returns int and bs->bl.request_alignment has 32bit unsigned type, but defined to be a power of 2 less than INT_MAX. So, we may establish, that INT_MAX is absolute maximum for any kind of alignment that may occur with the request. Note, that bdrv_get_cluster_size() is not documented to return power of 2, still bdrv_mark_request_serialising() behaves like it is. Also, backup uses bdi.cluster_size and is not prepared to it not being power of 2. So, let's establish that Qemu supports only power-of-2 clusters and alignments. So, alignment can't be greater than 2^30. Finally to be safe with calculations, to not calculate different maximums for different nodes (depending on cluster size and request_alignment), let's simply set QEMU_ALIGN_DOWN(INT64_MAX, 2^30) as absolute maximum bytes length for Qemu. Actually, it's not much less than INT64_MAX. OK, then, let's apply it to block/io. Let's consider all block/io entry points of offset/bytes: 4 bytes/offset interface functions: bdrv_co_preadv_part(), bdrv_co_pwritev_part(), bdrv_co_copy_range_internal() and bdrv_co_pdiscard() and we check them all with bdrv_check_request(). We also have one entry point with only offset: bdrv_co_truncate(). Check the offset. And one public structure: BdrvTrackedRequest. Happily, it has only three external users: file-posix.c: adopted by this patch write-threshold.c: only read fields test-write-threshold.c: sets obviously small constant values Better is to make the structure private and add corresponding interfaces.. Still it's not obvious what kind of interface is needed for file-posix.c. Let's keep it public but add corresponding assertions. After this patch we'll convert functions in block/io.c to int64_t bytes and offset parameters. We can assume that offset/bytes pair always satisfy new restrictions, and make corresponding assertions where needed. If we reach some offset/bytes point in block/io.c missing bdrv_check_request() it is considered a bug. As well, if block/io.c modifies a offset/bytes request, expanding it more then aligning up to request_alignment, it's a bug too. For all io requests except for discard we keep for now old restriction of 32bit request length. iotest 206 output error message changed, as now test disk size is larger than new limit. Add one more test case with new maximum disk size to cover too-big-L1 case. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20201203222713.13507-5-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>	6 years ago
Greg Kurz	009cde17a5	block: Move bdrv_drain_all_end_quiesce() to block_int.h This function is really an internal helper for bdrv_close(). Update its doc comment to make this clear and make the function private. Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <160387245480.131299.13430357162209598411.stgit@bahia> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>	6 years ago
Max Reitz	0b877d09df	block: Leave BDS.backing_{file,format} constant Parts of the block layer treat BDS.backing_file as if it were whatever the image header says (i.e., if it is a relative path, it is relative to the overlay), other parts treat it like a cache for bs->backing->bs->filename (relative paths are relative to the CWD). Considering bs->backing->bs->filename exists, let us make it mean the former. Among other things, this now allows the user to specify a base when using qemu-img to commit an image file in a directory that is not the CWD (assuming, everything uses relative filenames). Before this patch: $ ./qemu-img create -f qcow2 foo/bot.qcow2 1M $ ./qemu-img create -f qcow2 -b bot.qcow2 foo/mid.qcow2 $ ./qemu-img create -f qcow2 -b mid.qcow2 foo/top.qcow2 $ ./qemu-img commit -b mid.qcow2 foo/top.qcow2 qemu-img: Did not find 'mid.qcow2' in the backing chain of 'foo/top.qcow2' $ ./qemu-img commit -b foo/mid.qcow2 foo/top.qcow2 qemu-img: Did not find 'foo/mid.qcow2' in the backing chain of 'foo/top.qcow2' $ ./qemu-img commit -b $PWD/foo/mid.qcow2 foo/top.qcow2 qemu-img: Did not find '[...]/foo/mid.qcow2' in the backing chain of 'foo/top.qcow2' After this patch: $ ./qemu-img commit -b mid.qcow2 foo/top.qcow2 Image committed. $ ./qemu-img commit -b foo/mid.qcow2 foo/top.qcow2 qemu-img: Did not find 'foo/mid.qcow2' in the backing chain of 'foo/top.qcow2' $ ./qemu-img commit -b $PWD/foo/mid.qcow2 foo/top.qcow2 Image committed. With this change, bdrv_find_backing_image() must look at whether the user has overridden a BDS's backing file. If so, it can no longer use bs->backing_file, but must instead compare the given filename against the backing node's filename directly. Note that this changes the QAPI output for a node's backing_file. We had very inconsistent output there (sometimes what the image header said, sometimes the actual filename of the backing image). This inconsistent output was effectively useless, so we have to decide one way or the other. Considering that bs->backing_file usually at runtime contained the path to the image relative to qemu's CWD (or absolute), this patch changes QAPI's backing_file to always report the bs->backing->bs->filename from now on. If you want to receive the image header information, you have to refer to full-backing-filename. This necessitates a change to iotest 228. The interesting information it really wanted is the image header, and it can get that now, but it has to use full-backing-filename instead of backing_file. Because of this patch's changes to bs->backing_file's behavior, we also need some reference output changes. Along with the changes to bs->backing_file, stop updating BDS.backing_format in bdrv_backing_attach() as well. This way, ImageInfo's backing-filename and backing-filename-format fields will represent what the image header says and nothing else. iotest 245 changes in behavior: With the backing node no longer overriding the parent node's backing_file string, you can now omit the @backing option when reopening a node with neither a default nor a current backing file even if it used to have a backing node at some point. 273 also changes: The base image is opened without a format layer, so ImageInfo.backing-filename-format used to report "file" for the base image's overlay after blockdev-snapshot. However, the image header never says "file" anywhere, so it now reports $IMGFMT. Signed-off-by: Max Reitz <mreitz@redhat.com>	8 years ago
Max Reitz	549ec0d978	block: Inline bdrv_co_block_status_from_*() With bdrv_filter_bs(), we can easily handle this default filter behavior in bdrv_co_block_status(). blkdebug wants to have an additional assertion, so it keeps its own implementation, except bdrv_co_block_status_from_file() needs to be inlined there. Suggested-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>	8 years ago
Max Reitz	f1a7f18f07	block: Drop backing_bs() We want to make it explicit where bs->backing is used, and we have done so. The old role of backing_bs() is now effectively taken by bdrv_cow_bs(). Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com>	7 years ago
Max Reitz	d38d7eb8a5	block: Add chain helper functions Add some helper functions for skipping filters in a chain of block nodes. Signed-off-by: Max Reitz <mreitz@redhat.com>	7 years ago
Max Reitz	9a6fc88799	block: Add child access functions There are BDS children that the general block layer code can access, namely bs->file and bs->backing. Since the introduction of filters and external data files, their meaning is not quite clear. bs->backing can be a COW source, or it can be a filtered child; bs->file can be a filtered child, it can be data and metadata storage, or it can be just metadata storage. This overloading really is not helpful. This patch adds functions that retrieve the correct child for each exact purpose. Later patches in this series will make use of them. Doing so will allow us to handle filter nodes in a meaningful way. Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>	7 years ago
Alberto Garcia	7be2025258	qcow2: Add the 'extended_l2' option and the QCOW2_INCOMPAT_EXTL2 bit Now that the implementation of subclusters is complete we can finally add the necessary options to create and read images with this feature, which we call "extended L2 entries". Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <6476caaa73216bd05b7bb2d504a20415e1665176.1594396418.git.berto@igalia.com> [mreitz: %s/5\.1/5.2/; fixed 302's and 303's reference output] Signed-off-by: Max Reitz <mreitz@redhat.com>	6 years ago

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