bzr 0.13 - Long silent spin trying to lock when lacking write permission to lockdir

[Charles Duffy]

When trying to run "bzr update" on a branch I don't have write 
permissions to, there's a long delay without any feedback while bzr sits 
and spins like so:

mkdir("/opt/build-limited-dumps/.bzr/repository/lock/pending.wvprs1r2y5qmm0jm3wke.tmp", 
0777) = -1 EACCES (Permission denied)
write(3, "contention on LockDir(file:///op"..., 290) = 290
open("/opt/build-limited-dumps/.bzr/repository/lock/held/info", 
O_RDONLY) = -1 ENOENT (No such file or directory)
write(3, "last_info: None, new info: None\n", 32) = 32
select(0, NULL, NULL, NULL, {1, 0})     = 0 (Timeout)
open("/dev/urandom", O_RDONLY)          = 4
read(4, "4\362)a\356\315\225}\366\35\375 at K\267\250]:I\263#", 20) = 20
close(4)                                = 0
mkdir("/opt/build-limited-dumps/.bzr/repository/lock/pending.gq5pmp5hut1s33olm1zz.tmp", 
0777) = -1 EACCES (Permission denied)

In this case (where the lock directory is owned by someone else), we're 
*never* going to be able to write to it; perhaps we should do some check 
to make sure we're ever going to be able to succeed.

(Actually, is -EACCES on creating a randomly-named directory an expected 
failure case even when there's lock contention? Maybe we should just be 
failing earlier; I'd expect there to be an error on the rename, not the 
create).