Re: git update-ref --stdin : too many open files

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Dec 23, 2014, 03:22 UTC
Message-ID: <20141223032228.GZ29365@google.com>
In-Reply-To: <5498D66B.5090807@gmail.com>

Hi Stefan,

Stefan Beller wrote:

> On 22.12.2014 13:22, Junio C Hamano wrote:
>> Loic Dachary <loic@dachary.org> writes:

>>> fatal: Unable to create /home/gitmirror/repositories/Ceph/ceph/refs/heads/pull/1917.lock': Too many open files

[...]

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>> Stefan, want to take a look?  I think we do need to keep the .lock
>> files without renaming while in transaction, but we do not have to
>> keep them open, so I suspect that a fix may be to split the commit
>> function into two (one to close but not rename, the other to
>> finalize by renaming) or something.

Makes sense.

> Sounds reasonable. Though by closing the file we're giving up again a
> bit of safety. If we close the file everyone could tamper with the lock
> file. (Sure they are not supposed to touch it, but they could)

At least on Linux, keeping a file open doesn't offer any protection against someone else deleting it. (It also doesn't offer any protection against someone updating the ref directly. ;-) Opening the corresponding .lock file with O_EXCL is part of the contract for updating refs.)

Thanks, Jonathan