Trying to infinetely aquire a lock if flock is not implemented

[PeterZhizhin]

I'm using a lustre file system. Looks like it doesn't support flock syscall.

Here is a small script I'm trying to run:

import filelock

t = filelock.FileLock('test.lock')
with t:
  pass

Here is the output:

$ python test.py
... (Runs indefinitely)

Let's try running under strace:

$ strace python test.py
<A lot of garbage>
select(0, NULL, NULL, NULL, {0, 50000}) = 0 (Timeout)
open("test.lock", O_RDWR|O_CREAT|O_TRUNC|O_CLOEXEC, 0777) = 3
flock(3, LOCK_EX|LOCK_NB)               = -1 ENOSYS (Function not implemented)
close(3)                                = 0
select(0, NULL, NULL, NULL, {0, 50000}) = 0 (Timeout)
open("test.lock", O_RDWR|O_CREAT|O_TRUNC|O_CLOEXEC, 0777) = 3
flock(3, LOCK_EX|LOCK_NB)               = -1 ENOSYS (Function not implemented)
close(3)                                = 0
select(0, NULL, NULL, NULL, {0, 50000}) = 0 (Timeout)
open("test.lock", O_RDWR|O_CREAT|O_TRUNC|O_CLOEXEC, 0777) = 3
flock(3, LOCK_EX|LOCK_NB)               = -1 ENOSYS (Function not implemented)
close(3)                                = 0
select(0, NULL, NULL, NULL, {0, 50000}) = 0 (Timeout)
open("test.lock", O_RDWR|O_CREAT|O_TRUNC|O_CLOEXEC, 0777) = 3
flock(3, LOCK_EX|LOCK_NB)               = -1 ENOSYS (Function not implemented)
close(3)                                = 0
<And so on>

Solution: inside UnixFileLock do not ignore all exceptions. If OSError is raised with errno=ENOSYS, then show a warning, delete the lock file and fallback to SoftFileLock.

[jarednielsen]

Also hitting this issue. Any resolution?

[gaborbernat]

Hello, if you make a PR for this to fix it (with tests) we would be happy to review it, thanks!