Change in vdsm[master]: vm: improve extension check in extendDrivesIfNeeded

abaron at redhat.com abaron at redhat.com
Wed Nov 20 07:15:44 UTC 2013


Ayal Baron has posted comments on this change.

Change subject: vm: improve extension check in extendDrivesIfNeeded
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Patch Set 1:

(3 comments)

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Commit Message
Line 3: AuthorDate: 2013-11-14 09:08:08 -0500
Line 4: Commit:     Federico Simoncelli <fsimonce at redhat.com>
Line 5: CommitDate: 2013-11-19 10:38:09 -0500
Line 6: 
Line 7: vm: improve extension check in extendDrivesIfNeeded
improve how? why?
Line 8: 
Line 9: Change-Id: Ide5034cd5d87451c06a2ba034011fdf5696440e6


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File vdsm/vm.py
Line 2299:             # When an extension is needed we compute the maxium allowed size
Line 2300:             # taking in account the qcow2 format overhead and rounding it up
Line 2301:             # to the next volume chunk.
Line 2302:             extChunkBytes = drive.VOLWM_CHUNK_MB * constants.MEGAB
Line 2303:             totAlloc = capacity * (1.0 + QCOW2_OVERHEAD)
Same result but possibly more legible?
overhead = capacity * QCOW2_OVERHEAD
totAlloc = capacity + overhead
(I think this makes the part in the comment about the overhead redundant)
Line 2304:             maxAlloc = (
Line 2305:                 int((totAlloc + extChunkBytes - 1) / extChunkBytes) *
Line 2306:                 extChunkBytes
Line 2307:             )


Line 2307:             )
Line 2308: 
Line 2309:             # NOTE: the intent of this check is to prevent faulty images to
Line 2310:             # trick qemu in requesting extremely large extensions (BZ#998443).
Line 2311:             if curAlloc > maxAlloc:
1. Meaning this patch cannot go in? so -1 its verification or something?
2. Assuming (1) is correct then we will only be able to accept this patch if we have a way to fix existing volumes (reclaim leaked clusters)
Line 2312:                 self.log.error(
Line 2313:                     "Improbable extension request for volume %s on domain "
Line 2314:                     "%s, pausing the VM to avoid corruptions (capacity: %s, "
Line 2315:                     "allocated: %s, physical: %s, max allocation: %s)",


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Gerrit-MessageType: comment
Gerrit-Change-Id: Ide5034cd5d87451c06a2ba034011fdf5696440e6
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Federico Simoncelli <fsimonce at redhat.com>
Gerrit-Reviewer: Ayal Baron <abaron at redhat.com>
Gerrit-Reviewer: Federico Simoncelli <fsimonce at redhat.com>
Gerrit-Reviewer: Sergey Gotliv <sgotliv at redhat.com>
Gerrit-Reviewer: oVirt Jenkins CI Server
Gerrit-HasComments: Yes


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