[Gluster-devel] Here is linkat(2) again

Emmanuel Dreyfus manu at netbsd.org
Sat Jun 2 16:48:18 UTC 2012

I tracked down this problem this problem on release-3.3/NetBSD

Test case, that seems to work fine:

$ ln -s a b
$ ls -l b
lrwxrwxrwx  0 manu  manu  1 Jun  2 17:46 b -> a

But on bricks logs:

[2012-06-02 17:49:26.920400] W [posix-handle.c:461:posix_handle_hard]
0-pfs-posix: link /export/wd3a/manu/symlink/b ->
failed (No such file or directory)
[2012-06-02 17:49:26.920484] E [posix.c:1277:posix_symlink] 0-pfs-posix:
setting gfid on /export/wd3a/manu/symlink/b failed

This is because link(2) is done with a symlink target, and the symlink
leads to nowhere. BSD link(2) first resolves the symlink and get ENOENT.
Linux link(2) operates on the symlink itself, not its target, and works.

Both behavior are standard compliant. The only way to work this around
in a portable way is to use newer standard function linkat(2), which
allow the caller to specify if symlinks must be followed or not.

Here is the change that fixes the above problem. Please approve and
merge! http://review.gluster.com/3507

Emmanuel Dreyfus
manu at netbsd.org

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