Messages in this thread | | | Date | Thu, 6 Dec 2007 00:33:45 +0100 | From | Nick Piggin <> | Subject | Re: [patch] ext2: xip check fix |
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On Wed, Dec 05, 2007 at 04:43:16PM +0100, Carsten Otte wrote: > Nick Piggin wrote: > >Am I missing something here? I wonder how s390 works without this change? > > > >-- > >ext2 should not worry about checking sb->s_blocksize for XIP before the > >sb's blocksize actually gets set. > > > >Signed-off-by: Nick Piggin <npiggin@suse.de> > >--- > >Index: linux-2.6/fs/ext2/super.c > >=================================================================== > >--- linux-2.6.orig/fs/ext2/super.c > >+++ linux-2.6/fs/ext2/super.c > >@@ -844,8 +844,7 @@ static int ext2_fill_super(struct super_ > > > > blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size); > > > >- if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) || > >- (sb->s_blocksize != blocksize))) { > >+ if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) { > > if (!silent) > > printk("XIP: Unsupported blocksize\n"); > > goto failed_mount; > "blocksize" contains the blocksize of the device here, and > sb->s_blocksize does contain the filesystem block size as saved in the > super block.
You mean blocksize is the size of the ext2 block, and s_blocksize is the default size of the block device.
> Xip does only work, if both do match PAGE_SIZE because it > does'nt support multiple calls to direct_access in the get_xip_page > address space operation. Thus we check both here, actually this was > changed from how it looks after your patch as a bugfix where our > tester tried a 4k filesystem on a 2k blockdev. > Did I miss something?
However, the bdev block size may be changed with sb_set_blocksize. It doesn't actually have to match the hardware sector size -- if this does matter for XIP, then I think you need some other check here.
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