[master] Optimize data cluster format for VHD and QCOW#7106
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last-genius wants to merge 8 commits into
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[master] Optimize data cluster format for VHD and QCOW#7106last-genius wants to merge 8 commits into
last-genius wants to merge 8 commits into
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This allows to switch on the more efficient interval format later. (QCOW always uses the new format) Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech> (cherry picked from commit 1aa52ef)
This command returns a more efficient representation of allocated clusters (when compared to read_headers), utilizing a sparse interval format instead of returning every single allocated cluster. This is the more efficient option, decreasing the filesize and memory usage in vhd-tool, but it's currently under a feature flag, so it's added as a new command instead of replacing read_headers immediately. Cram test for read_headers is still passing, so this refactoring has preserved the legacy format. Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech> (cherry picked from commit fa4f516)
Since the runtime feature flag vhd_legacy_blocks_format determines which block format is used to describe allocated VHD clusters, this requires duplicate parse_header_interval functions for VHD and QCOW. The right functions are selected in stream_vdi based on the feature flag. Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech> (cherry picked from commit 5457512)
…er allocation Instead of using a set with every individual allocated cluster index as a member, use a sorted list of intervals to verify if cluster is allocated - this uses much less memory and directly follows from the JSON format qcow-stream-tool and vhd-tool output now. Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech> (cherry picked from commit 1fc8ee7)
…_clusters nonzero_clusters no longer contain every single allocated cluster and instead are intervals of allocated clusters. Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech> (cherry picked from commit a52b126)
Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech> (cherry picked from commit f9db34b)
This proves much more reliable than code based on ocaml-qcow. Since qemu-img has a different format (with the needed information spread across two files resulting from calls to 'qemu-img info' and 'qemu-img map'), change the parsing code in vhd_qcow_parsing and qcow2-to-stdout. Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech> (cherry picked from commit 3f6f6dd)
qemu-img is now used to determine allocated clusters, so this command is no longer needed. Signed-off-by: Andrii Sultanov <andriy.sultanov@vates.tech> (cherry picked from commit 829c018)
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Jun 1, 2026
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This is a forward-port of #6895 (with the exception of commits later reverted in #7030 and #7022).
Changes to VHD code are gated behind a feature flag (with previous behaviour kept by default). XCP-ng has been running the new VHD and QCOW code for a while now with no issues.
This PR needs to be merged before the corresponding xs-opam PR (xapi-project/xs-opam#768)