[LU-6299] OSP does not handle zero length xattr values well

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.8.0
• Affects Version/s: Lustre 2.7.0
• Severity: 3
• Assignee: Di Wang
• Reporter: John Hammond

Description

The OSP/OUT code assumes that xattr values always have a non-zero length. For example,

static int out_xattr_set(struct tgt_session_info *tsi)
{
         ...
        buf = object_update_param_get(update, 1, &buf_len);
        if (buf == NULL || buf_len == 0) {
                CERROR("%s: empty buf for xattr set: rc = %d\n",
                       tgt_name(tsi->tsi_tgt), -EPROTO);
                RETURN(err_serious(-EPROTO));
        }
        ...

Here is what happens on 2.6.94-18-g7c82a9c

t:lustre-release# cd /mnt/lustre
t:lustre# lfs mkdir -c4 d0
t:lustre# setfattr -n user.foo d0

Message from syslogd@t at Feb 26 10:53:15 ...
 kernel:[  409.511761] LustreError: 4876:0:(osp_object.c:1132:__osp_xattr_set()) ASSERTION( buf->lb_len > 0 && buf->lb_buf != ((void *)0) ) failed: 

Message from syslogd@t at Feb 26 10:53:15 ...
 kernel:[  409.515616] LustreError: 4876:0:(osp_object.c:1132:__osp_xattr_set()) LBUG

Comments

[Peter Jones]

Landed for 2.8

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch http://review.whamcloud.com/14787/
Subject: LU-6299 osp: zero-length EA xattr_set for striped_dir
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 1cf0952fc28b061932cec40022486a7f78573414

[Gerrit Updater]

wangdi ([e-mail]) uploaded a new patch: http://review.whamcloud.com/14787
Subject: LU-6299 osp: zero-length EA xattr_set for striped_dir
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 411b1631c005fd7e80f98f56b932363b9c3e13e5

[Di Wang]

Ah, did not notice this one, will work on it today

[Andreas Dilger]

Di, any update on this one?

[Andreas Dilger]

It surprises me that we don't have a test for setting zero-length xattrs. Maybe we do for regular files and not directories? Please add one for this test. The sanity test_102h and test_102k seem like they are close, but don't start with a zero-length xattr, and don't run on a directory. Seems a test_102hb is needed for testing xattrs on directories.