[LU-11109] zero length xattrs handled incorrectly when xattr cache disabled or bypassed

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.12.0
• Labels: xattr
• Severity: 3
• Assignee: John Hammond
• Reporter: John Hammond

Description

When xattr caching is disabled or bypassed extended attributes with zero length values are not handled correctly:

o:~# cd /mnt/lustre
o:lustre# lctl set_param llite.*.xattr_cache=1
llite.lustre-ffff8c4ac8a60000.xattr_cache=1
o:lustre# rm -f f0
o:lustre# touch f0
o:lustre# setfattr -n user.blah f0
o:lustre# getfattr -d -m- f0
# file: f0
lustre.lov=0s0AvRCwEAAAADAAAAAAAAAAEEAAACAAAAAAAQAAEAAAADAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
trusted.link=0s3/HqEQEAAAAsAAAAAAAAAAAAAAAAAAAAABQAAAACAAAABwAAAAEAAAAAZjA=
trusted.lma=0sAAAAAAAAAAABBAAAAgAAAAMAAAAAAAAA
trusted.lov=0s0AvRCwEAAAADAAAAAAAAAAEEAAACAAAAAAAQAAEAAAADAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
trusted.version=0sDAAAAAEAAAA=
user.blah

o:lustre# lctl set_param llite.*.xattr_cache=0
llite.lustre-ffff8c4ac8a60000.xattr_cache=0
o:lustre# getfattr -d -m- f0
# file: f0
lustre.lov=0s0AvRCwEAAAADAAAAAAAAAAEEAAACAAAAAAAQAAEAAAADAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
trusted.link=0s3/HqEQEAAAAsAAAAAAAAAAAAAAAAAAAAABQAAAACAAAABwAAAAEAAAAAZjA=
trusted.lma=0sAAAAAAAAAAABBAAAAgAAAAMAAAAAAAAA
trusted.lov=0s0AvRCwEAAAADAAAAAAAAAAEEAAACAAAAAAAQAAEAAAADAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
trusted.version=0sDAAAAAEAAAA=
f0: user.blah: No such attribute

I noticed this while looking at LU-11074 but this is not the underlying cause of that bug.

Comments

[Peter Jones]

Landed for 2.12

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch https://review.whamcloud.com/32755/
Subject: LU-11109 mdt: handle zero length xattr values correctly
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 1e4164a1254d7fb75e49af73994d2e53864536ab

[John Hammond]

The first change is logically independent of the others but they should be used together for LU-11074.

[James A Simmons]

John are the patches a series or independent?

[Gerrit Updater]

John L. Hammond ([e-mail]) uploaded a new patch: https://review.whamcloud.com/32755
Subject: LU-11109 mdt: handle zero length xattr values correctly
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: c4a00691479e245a2134dc03574448c652e38f13