[LU-2231] ZFS OSD not setting dnode parent field

Duplicate — Fri, 19 Apr 2013 20:41:36 +0000

File foo created from a lustre client:

Object  lvl   iblk   dblk  dsize  lsize   %full  type
   197    1    16K   128K     1K   128K    0.00  ZFS plain file
                                    192   bonus  System attributes
    dnode flags: USED_BYTES USERUSED_ACCOUNTED SPILL_BLKPTR
    dnode maxblkid: 0
    path    ???<object#197>
    uid     840000038
    gid     840000038
    atime   Fri Mar 30 01:51:12 2012
    mtime   Fri Mar 30 01:51:23 2012
    ctime   Fri Mar 30 01:51:23 2012
    crtime  Fri Mar 30 01:51:12 2012
    gen     1015
    mode    100644
    size    0
    parent  0
    links   1
    pflags  0
    rdev    0x0000000000000000

It appears that the SA_ZPL_PARENT() is used in several places to process directories (e.g. avoiding circular directory references), so it definitely needs to be set for directories. It also seems to be set for regular files, but it is difficult to determine if it is required or not.

Since there is only a single parent directory field, we should determine what the behaviour of the parent field is for hard links and renames:

mkdir a b
ls -li       # get inode numbers
zdb {check parent} .
touch a/foo
zdb {check parent} a/foo
ln a/foo b/bar
zdb {check parent} b/bar
rm {link from current parent}
zdb {check parent of other link}

touch a/baz
zdb {check parent} a/baz
mv a/baz b/baz
zdb {check parent} b/baz

I suspect that the parent will be updated on rename (it would have to be for directories), but I'm unsure what will happen if the current parent link will be dropped. I suspect it will be set to 0.

Whamcloud Community JIRA

[LU-2231] ZFS OSD not setting dnode parent field