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Diffstat (limited to 'results/classifier/zero-shot/108/other/1850000')
| -rw-r--r-- | results/classifier/zero-shot/108/other/1850000 | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/results/classifier/zero-shot/108/other/1850000 b/results/classifier/zero-shot/108/other/1850000 new file mode 100644 index 000000000..5610a7b4c --- /dev/null +++ b/results/classifier/zero-shot/108/other/1850000 @@ -0,0 +1,158 @@ +debug: 0.884 +device: 0.859 +semantic: 0.855 +PID: 0.836 +other: 0.822 +permissions: 0.802 +vnc: 0.796 +performance: 0.793 +graphic: 0.788 +KVM: 0.788 +boot: 0.783 +files: 0.773 +network: 0.628 +socket: 0.560 + +4.1.0 bogus QCOW2 corruption reported after compress + +Creating a compressed image then running `qemu-img check <..>.qcow2' on said image seems to report bogus corruption in some (but not all) cases: + +Step 1. + +# qemu-img info win7-base.qcow2 +image: win7-base.qcow2 +file format: qcow2 +virtual size: 20 GiB (21474836480 bytes) +disk size: 12.2 GiB +cluster_size: 65536 +Format specific information: + compat: 1.1 + lazy refcounts: true + refcount bits: 16 + corrupt: false + +# qemu-img check win7-base.qcow2 +No errors were found on the image. +327680/327680 = 100.00% allocated, 0.00% fragmented, 0.00% compressed clusters +Image end offset: 21478375424 + +Step 2. + +# qemu-img convert -f qcow2 -O qcow2 -c win7-base.qcow2 test1-z.qcow2 + +Step 3. + +# qemu-img info test1-z.qcow2 +image: test1-z.qcow2 +file format: qcow2 +virtual size: 20 GiB (21474836480 bytes) +disk size: 5.78 GiB +cluster_size: 65536 +Format specific information: + compat: 1.1 + lazy refcounts: false + refcount bits: 16 + corrupt: false + +# qemu-img check test1-z.qcow2 +ERROR cluster 1191 refcount=1 reference=2 +ERROR cluster 1194 refcount=1 reference=4 +ERROR cluster 1195 refcount=1 reference=7 +ERROR cluster 1196 refcount=1 reference=7 +ERROR cluster 1197 refcount=1 reference=6 +ERROR cluster 1198 refcount=1 reference=4 +ERROR cluster 1199 refcount=1 reference=4 +ERROR cluster 1200 refcount=1 reference=5 +ERROR cluster 1201 refcount=1 reference=3 +<...> snip many errors +Leaked cluster 94847 refcount=3 reference=0 +Leaked cluster 94848 refcount=3 reference=0 +Leaked cluster 94849 refcount=11 reference=0 +Leaked cluster 94850 refcount=14 reference=0 + +20503 errors were found on the image. +Data may be corrupted, or further writes to the image may corrupt it. + +20503 leaked clusters were found on the image. +This means waste of disk space, but no harm to data. +197000/327680 = 60.12% allocated, 89.32% fragmented, 88.50% compressed clusters +Image end offset: 6216220672 + + +The resultant image seems to work fine in a VM when used as a backing file. + +Interestingly, if I substitute a qemu-img binary from qemu-4.0 then no errors are reported. + +# /tmp/qemu-img check test1-z.qcow2 +No errors were found on the image. +197000/327680 = 60.12% allocated, 89.32% fragmented, 88.50% compressed clusters +Image end offset: 6216220672 + +Is the image corrupted or not? I'm guessing not. + +Just in case it matters, this is ext4 fs on rotational disk. Latest Arch Linux but self compiled 4.1.0 with recent QCOW2 corruption fixes added. + +I haven't tried latest trunk but might do so if time permits. + +Current trunk still displays the problem. + +A git bisection between 4.0.0 and 4.1.0 revealed: + +b6c246942b14d3e0dec46a6c5868ed84e7dbea19 is the first bad commit +commit b6c246942b14d3e0dec46a6c5868ed84e7dbea19 +Author: Alberto Garcia <email address hidden> +Date: Fri May 10 19:22:54 2019 +0300 + + qcow2: Define and use QCOW2_COMPRESSED_SECTOR_SIZE + + When an L2 table entry points to a compressed cluster the space used + by the data is specified in 512-byte sectors. This size is independent + from BDRV_SECTOR_SIZE and is specific to the qcow2 file format. + + The QCOW2_COMPRESSED_SECTOR_SIZE constant defined in this patch makes + this explicit. + + Signed-off-by: Alberto Garcia <email address hidden> + Signed-off-by: Kevin Wolf <email address hidden> + + block/qcow2-cluster.c | 5 +++-- + block/qcow2-refcount.c | 25 ++++++++++++++----------- + block/qcow2.c | 3 ++- + block/qcow2.h | 4 ++++ + 4 files changed, 23 insertions(+), 14 deletions(-) + + + + + +There is definitely a bug in that patch, and that is that QCOW2_COMPRESSED_SECTOR_MASK is an unsigned int instead of a uint64_t (so the mask is too small). + +It looks like the bug has existed in some places before that patch (because they use ~511 as a mask), but not in others. + +This would explain why the bug is visible only for some images, namely for those with a compressed size of more than 4 GB, I presume. + + +And indeed, fixing QCOW2_COMPRESSED_SECTOR_MASK to be an unsigned long long fixes the bug. I’ll send a patch (but I’ll have to write a more simple and quicker test case first). + +Max + +Forgot to say that I sent a patch: + +https://lists.nongnu.org/archive/html/qemu-block/2019-10/msg01764.html + + +Thanks for reporting! + +Max + +Thank you Max. + +Can confirm your patch fixes my issue (qemu-img check ...) + +Not sure about those other code paths. I don't use internal snapshots and I'm not sure under which circumstances qcow2_free_any_clusters() gets exercised. + +Just for good measure, with patch applied I created another >4GB compressed image then booted it a few times and all seems fine. + +Fix has been included in QEMU v4.2: +https://git.qemu.org/?p=qemu.git;a=commitdiff;h=24552feb6ae2f615b76c2 + |