Bug 444049
| Summary: | kernel dm snapshot: corruption detected after write to origin volumes | ||||||
|---|---|---|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 4 | Reporter: | Corey Marthaler <cmarthal> | ||||
| Component: | kernel | Assignee: | Mikuláš Patočka <mpatocka> | ||||
| Status: | CLOSED DUPLICATE | QA Contact: | Corey Marthaler <cmarthal> | ||||
| Severity: | high | Docs Contact: | |||||
| Priority: | high | ||||||
| Version: | 4.6.z | CC: | agk, dwysocha, edamato, heinzm, jbrassow, mbroz, mpatocka, prockai | ||||
| Target Milestone: | rc | Keywords: | Regression | ||||
| Target Release: | --- | ||||||
| Hardware: | All | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2009-01-08 09:47:13 UTC | Type: | --- | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Bug Depends On: | |||||||
| Bug Blocks: | 461297 | ||||||
| Attachments: |
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Is the corruption permanent or transient? After the test finishes and there is no more any IO, do the snapshots contain correct data? Transient corruption is a known problem, there is already fix for upstream. I don't know about any permanent corruption of snapshots with the same chunksize. Created attachment 304319 [details]
Fix read-realloc race in RHEL 4
Try this patch, if it fixed the test. It is backport for the pending upstream
patch that fixes the read-fs-realloc race condition.
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release. This bugzilla has Keywords: Regression. Since no regressions are allowed between releases, it is also being proposed as a blocker for this release. Please resolve ASAP. Updating PM score. Resolving as a duplicate of bug #175830 --- it could be duplicate but it is impossible to say certainly without reproducing this bug and further testing. If anyone ever sees this bug after fix for #175830 was applied, reopen it. *** This bug has been marked as a duplicate of bug 175830 *** |
Description of problem: I been able to reproduce this issue now quite a few times while running the 4.6.Z regression tests. I create an origin and a few snapshot volumes. Then with the tool b_iogen/b_doio, I read the snap, then write to the origin, and verify that the snap didn't change. I've been seeing that it has however. The snaps all have the same 32k chunksizes even though their names imply that is not so. block_snap128 snapper swi-a- 3.50G origin 13.82 block_snap16 snapper swi-a- 3.50G origin 23.31 block_snap256 snapper swi-a- 3.50G origin 8.59 block_snap32 snapper swi-a- 3.50G origin 20.27 block_snap64 snapper swi-a- 3.50G origin 17.32 origin snapper owi-a- 4.00G [root@taft-01 ~]# /usr/tests/sts-rhel4.6/bin/b_iogen -o -m random -f direct -i 15s -s write,writev -t1000b -T10000b -d /dev/snapper/origin:/dev/snapper/block_snap256 | /usr/tests/sts-rhel4.6/bin/b_doio -v b_iogen starting up with the following: Iterations: 15s Seed: 31265 Offset-mode: random Single Pass: off Overlap Flag: on Mintrans: 512000 Maxtrans: 5120000 Syscalls: write writev Flags: direct Test Devices: Path Size (bytes) --------------------------------------------------------------- /dev/snapper/origin 4294967296 Snap Devices: /dev/snapper/block_snap256 *** DATA COMPARISON ERROR /dev/snapper/block_snap256 (Offset 785754112) *** Started at byte 55296 Expected 0x66(f) 0x74(t) 0x2d(-) 0x30(0) 0x31(1) 0x3a(:) 0x62(b) 0x5f(_) 0x64(d) 0x6f(o) ... Got 0x4b(K) 0x4b(K) 0x4b(K) 0x4b(K) 0x4b(K) 0x4b(K) 0x4b(K) 0x4b(K) 0x4b(K) 0x4b(K) ... Version-Release number of selected component (if applicable): 2.6.9-67.0.15.ELsmp lvm2-2.02.27-2.el4_6.1 How reproducible: Often