[PATCH V3] tdb: introduce tdb_chainlock_read_nonblock(), a nonblock variant of tdb_chainlock_read()

[Jeremy Allison]

On Tue, Apr 28, 2015 at 11:50:45AM +0300, Alexander Drozdov wrote:
> tdb has nonblock variants for many lock functions, for example:
> 
> tdb_lockall() / tdb_lockall_nonblock()
> tdb_lockall_read() / tdb_lockall_read_nonblock()
> tdb_chainlock() / tdb_chainlock_nonblock()
> 
> But there hasn't been nonblock variant for tdb_chainlock_read().

Reviewed-by: Jeremy Allison <jra at samba.org>

If Volker is happy with the .sigs fixup I'll push.