Re: [Btrfs-devel] btrfs and git-reflog

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Jan 25, 2008, 17:09 UTC
Message-ID: <alpine.LFD.1.00.0801250905570.14161@hp.linux-foundation.org>
In-Reply-To: <200801251050.16697.chris.mason@oracle.com>

On Fri, 25 Jan 2008, Chris Mason wrote:

Show 5 quoted lines

> 
> The btrfs patch below changes my readdir code to force the
> directory f_pos field to the max offset allowed when we've
> seen all the directory entries.  This prevents the readdir
> call from looping forever in the face of newly added files.

I think such a change may be sensible if we also taught the Linux VFS layer about it (so that we could avoid the costly parts of readdir() getting a semaphore etc the next call), but in this particular format it's just an ugly hack for what is a git bug.

> But, git might want to add some checks to see if it has
> already processed things.

Yes indeed. This is clearly git mis-using "readdir()", and should be 
fixed. It could happen on other filesystems, and very much including ones 
where there is no option of just "fixing" the filesystem (including 
Linux: not everybody can upgrade their kernels just because git makes 
some broken assumptions).

		Linus