In article <[EMAIL PROTECTED]> you write: >On May 02, 2007 18:23 +0530, Amit K. Arora wrote: >> On Sun, Apr 29, 2007 at 10:25:59PM -0700, Chris Wedgwood wrote: >> > On Mon, Apr 30, 2007 at 10:47:02AM +1000, David Chinner wrote: >> > >> > > For FA_ALLOCATE, it's supposed to change the file size if we >> > > allocate past EOF, right? >> > >> > I would argue no. Use truncate for that. >> >> The patch I posted for ext4 *does* change the filesize after >> preallocation, if required (i.e. when preallocation is after EOF). >> I may have to change that, if we decide on not doing this. > >I think I'd agree - it may be useful to allow preallocation beyond EOF >for some kinds of applications (e.g. PVR preallocating live TV in 10 >minute segments or something, but not knowing in advance how long the >show will actually be recorded or the final encoded size).
I have an application (diablo dreader) where the header-info database basically consists of ~40.000 files, one for each group (it's more complicated that that, but never mind that now). If you grow those files randomly by a few hundred bytes every update, the filesystem gets hopelessly fragmented. I'm using XFS with preallocation turned on, and biosize=18 (which makes it preallocate in blocks of 256KB), and a homebrew patch that leaves the preallocated space on disk preallocated even if the file is closed .. and it helps enormously. Mike. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
