On Mon, 2005-04-18 at 12:22 +0100, Christoph Hellwig wrote: > > Mingming Cao <[EMAIL PROTECTED]> said: > > The ext2 handle discard preallocation differently at that time, it discard > > the > > preallocation at each iput(), not in input_final(), so we think it's > > unnecessary to thrash it so frequently, and the right thing to do, as we did > > for ext3 reservation, discard preallocation on last iput(). So we moved the > > ext2_discard_preallocation from ext2_put_inode(0 to ext2_clear_inode. > > > > Since ext2 preallocation is doing pre-allocation on disk, so it is possible > > that at the unmount time, someone is still hold the reference of the inode, > > so > > the preallocation for a file is not discard yet, so we still mark those > > blocks > > allocated on disk, while they are not actually in the inode's block map, so > > fsck will catch/fix that error later. > > > > This is not a issue for ext3, as ext3 reservation(pre-allocation) is done in > > memory. > > Shouldn't we have a pass to discard on unmount instead? ->put_inode is > a really bad interface and all usages including this one are racy (not that > it matters too much here, but I'd like to get rid of it eventually).
> As a band-aid to avoid the corruption it's certainly okay (and needed), but > we should try to fix this for real. Mingming, do you want to look into it > or should I put it on my TODO list? > > Hi Christoph, I dislike the fact that ext2 discard preallocation on every iput rather than the last iput. Yes, I think doing a check of the preallocated blocks at umount time is doable. Please go for it. Thanks for asking. Mingming - 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/
