[LU-216] Fix fiemap locking issue in 2.6.32 kernels

• Type: Bug
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.2.0, Lustre 1.8.6
• Affects Version/s: Lustre 2.1.0, Lustre 1.8.6
• Severity: 3
• Bugzilla ID: 23,780
• Assignee: Zhenyu Xu
• Reporter: Cory Spitz

Description

The patch from Lustre Bugzilla 23780 attachment 31890 was added for RHEL6 support with git commit e550abd05cf7ffddaedbef996be1baaae0912b4a, but a better long term fix is needed.

Johann L. writes in Lustre Bugzilla 23780 comment #28:
> The drawback of this patch is a potential race with fiemap (i did not revert
> the git kernel commit fab3a549e204172236779f502eccb4f9bf0dc87d totally).

and follows up in Lustre Bugzilla 23780 comment #34:
> Please note that this patch is a short term solution.
> Girish, it would be great if you could come up with another patch which takes
> i_data_sem write reference where it is needed in ext4_walk_space().

b1_8 also still requires the fix for SLES 11 SP1.

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Info required for matching: sanity-benchmark test_fsx fsx