f696e6c6e2
- kvm-block-Expand-block-status-mode-from-bool-to-flags.patch [RHEL-88435 RHEL-88437] - kvm-file-posix-gluster-Handle-zero-block-status-hint-bet.patch [RHEL-88435 RHEL-88437] - kvm-block-Let-bdrv_co_is_zero_fast-consolidate-adjacent-.patch [RHEL-88435 RHEL-88437] - kvm-block-Add-new-bdrv_co_is_all_zeroes-function.patch [RHEL-88435 RHEL-88437] - kvm-iotests-Improve-iotest-194-to-mirror-data.patch [RHEL-88435 RHEL-88437] - kvm-mirror-Minor-refactoring.patch [RHEL-88435 RHEL-88437] - kvm-mirror-Pass-full-sync-mode-rather-than-bool-to-inter.patch [RHEL-88435 RHEL-88437] - kvm-mirror-Allow-QMP-override-to-declare-target-already-.patch [RHEL-88435 RHEL-88437] - kvm-mirror-Drop-redundant-zero_target-parameter.patch [RHEL-88435 RHEL-88437] - kvm-mirror-Skip-pre-zeroing-destination-if-it-is-already.patch [RHEL-88435 RHEL-88437] - kvm-mirror-Skip-writing-zeroes-when-target-is-already-ze.patch [RHEL-88435 RHEL-88437] - kvm-iotests-common.rc-add-disk_usage-function.patch [RHEL-88435 RHEL-88437] - kvm-tests-Add-iotest-mirror-sparse-for-recent-patches.patch [RHEL-88435 RHEL-88437] - kvm-mirror-Reduce-I-O-when-destination-is-detect-zeroes-.patch [RHEL-88435 RHEL-88437] - Resolves: RHEL-88435 (--migrate-disks-detect-zeroes doesn't take effect for disk migration [rhel-10.1]) - Resolves: RHEL-88437 (Disk size of target raw image is full allocated when doing mirror with default discard value [rhel-10.1])
91 lines
3.4 KiB
Diff
91 lines
3.4 KiB
Diff
From e101b9872f9b3f6c5e128f29d7c3bb91faca362b Mon Sep 17 00:00:00 2001
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From: Eric Blake <eblake@redhat.com>
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Date: Fri, 9 May 2025 15:40:20 -0500
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Subject: [PATCH 03/14] block: Let bdrv_co_is_zero_fast consolidate adjacent
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extents
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RH-Author: Eric Blake <eblake@redhat.com>
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RH-MergeRequest: 363: blockdev-mirror: More efficient handling of sparse mirrors
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RH-Jira: RHEL-88435 RHEL-88437
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Commit: [3/14] 4520f7ef5bcc5803413541e6f48bf750af3d31e0 (ebblake/centos-qemu-kvm)
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Some BDS drivers have a cap on how much block status they can supply
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in one query (for example, NBD talking to an older server cannot
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inspect more than 4G per query; and qcow2 tends to cap its answers
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rather than cross a cluster boundary of an L1 table). Although the
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existing callers of bdrv_co_is_zero_fast are not passing in that large
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of a 'bytes' parameter, an upcoming caller wants to query the entire
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image at once, and will thus benefit from being able to treat adjacent
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zero regions in a coalesced manner, rather than claiming the region is
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non-zero merely because pnum was truncated and didn't match the
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incoming bytes.
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While refactoring this into a loop, note that there is no need to
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assign pnum prior to calling bdrv_co_common_block_status_above() (it
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is guaranteed to be assigned deeper in the callstack).
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Signed-off-by: Eric Blake <eblake@redhat.com>
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Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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Message-ID: <20250509204341.3553601-18-eblake@redhat.com>
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(cherry picked from commit 31bf15d97dd1d205a3b264675f9a1b3bd1939068)
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Jira: https://issues.redhat.com/browse/RHEL-88435
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Jira: https://issues.redhat.com/browse/RHEL-88437
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Signed-off-by: Eric Blake <eblake@redhat.com>
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---
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block/io.c | 27 +++++++++++++++------------
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1 file changed, 15 insertions(+), 12 deletions(-)
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diff --git a/block/io.c b/block/io.c
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index e328402adc..64f4b1d22a 100644
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--- a/block/io.c
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+++ b/block/io.c
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@@ -2751,28 +2751,31 @@ int coroutine_fn bdrv_co_block_status(BlockDriverState *bs, int64_t offset,
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* by @offset and @bytes is known to read as zeroes.
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* Return 1 if that is the case, 0 otherwise and -errno on error.
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* This test is meant to be fast rather than accurate so returning 0
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- * does not guarantee non-zero data.
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+ * does not guarantee non-zero data; but a return of 1 is reliable.
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*/
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int coroutine_fn bdrv_co_is_zero_fast(BlockDriverState *bs, int64_t offset,
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int64_t bytes)
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{
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int ret;
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- int64_t pnum = bytes;
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+ int64_t pnum;
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IO_CODE();
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- if (!bytes) {
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- return 1;
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- }
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-
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- ret = bdrv_co_common_block_status_above(bs, NULL, false, BDRV_WANT_ZERO,
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- offset, bytes, &pnum, NULL, NULL,
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- NULL);
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+ while (bytes) {
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+ ret = bdrv_co_common_block_status_above(bs, NULL, false,
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+ BDRV_WANT_ZERO, offset, bytes,
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+ &pnum, NULL, NULL, NULL);
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- if (ret < 0) {
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- return ret;
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+ if (ret < 0) {
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+ return ret;
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+ }
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+ if (!(ret & BDRV_BLOCK_ZERO)) {
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+ return 0;
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+ }
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+ offset += pnum;
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+ bytes -= pnum;
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}
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- return (pnum == bytes) && (ret & BDRV_BLOCK_ZERO);
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+ return 1;
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}
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int coroutine_fn bdrv_co_is_allocated(BlockDriverState *bs, int64_t offset,
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--
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2.39.3
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