[LU-3344] Add open_by_handle() syscall for Lustre clients

• Type: New Feature
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.6.0
• Labels: patch
• Assignee: Jian Yu
• Reporter: Andreas Dilger

Description

The open_by_handle_at() and name_to_handle() functions were added to Linux 2.6.38, and allow opening files by a file handle instead of path traversal. This may be useful for HPC applications to reduce loading on the metadata server from repeated path traversal.

There is some chance this feature already works on Lustre, due to the re-use of the NFS exportfs_encode_fh() and exportfs_decode_fh() functions. This code needs a regression test in Lustre to verify it is working correctly, along with documentation in the user manual.

Issue Links

• is related to: LU-3717 Kernel panic in ll_encode_fh() while testing file handle syscalls on FC18 client

Comments

[Peter Jones]

Fixed in 2.6

[James A Simmons]

The last patch http://review.whamcloud.com/#/c/7247 has been merged. This ticket can be closed.

[James A Simmons]

Patch http://review.whamcloud.com/#/c/7247 has been updated and tested.

[root@spoon46 tests]# ./check_fhandle_syscalls temp-file /lustre/barry
fh_bytes: 32
fh_type: 151
fh_data: 0 4 0 0 2 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
check_fhandle_syscalls test Passed!

[James A Simmons]

I updated the patch. Even tho I was testing with a 3.11 kernel I couldn't get this to work but then I realized the kernel has to be configured with CONFIG_FHANDLE so I updated the autoconf test to handle this case. I also removed the FC18 condition for the sanity test since this is not the case for me.

[Peter Jones]

Yu, Jian will take over ensuring that this patch lands

[Peter Jones]

Bobbie

Could you please review and take care of this patch?

Thanks

Peter