On Wed, 3 Apr 2013, Theodore Ts'o wrote: > Date: Wed, 3 Apr 2013 10:35:54 -0400 > From: Theodore Ts'o <tytso@xxxxxxx> > To: Lukas Czerner <lczerner@xxxxxxxxxx> > Cc: linux-ext4@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] mke2fs: Disallow bigalloc with with bs < 4096 > > On Wed, Apr 03, 2013 at 03:51:39PM +0200, Lukas Czerner wrote: > > Currently there is nothing preventing user to create file system with > > bigalloc feature enabled and block size smaller than 4096 Bytes. However > > such combination does not make much sense at all because the whole point > > of bigalloc is to have bigger allocation units. > > > > This patch disallow such combination. > > This makes sense by default but I do see a point in allowing it for > testing purposes --- specifically, it allows us to verify that > bigalloc works on architectures such as PowerPC and Itanium where page > size is greater than the 4k block size. So maybe a developer mode set > via mke2fs.conf? Yes, I though about that and I wanted to know what the general opinion is. I'll prepare the patch which makes this tunable, but restricted by default. > > Another option would be to enforce that we only support bigalloc file > systems where the blocksize == pagesize, but that means we wouldn't be > able to mount 4k bigalloc file systems on architectures with a 8k or > 16k page size. Unfortunately we can't do that for the reasons you mentioned. Thanks! -Lukas > > - Ted > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
