Re: ext[23]/lilo/2.5.{68,69,70} -- blkdev_put() problem?

[Unai Garro Arrazola <Unai.Garro@ee.ed.ac.uk>]

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I just got the time to checked. It works great, thanks! Where can I send this 
box of chocolates as gratitude? ;-)

On Friday 13 June 2003 09:01, Andrew Morton wrote:
> This should fix it.
>
>
>
> Once the blockdev inode for /dev/ram0 is dirtied we have a memory-backed
> inode on the blockdev superblock's s_dirty list.
>
> sync_sb_inodes() sees the memory-backed inode on the superblock and assumes
> that all the other inodes on the superblock are also memory-backed.  This
> is not true for the blockdev superblock!  We forget to write out dirty
> pages against the following blockdevs.
>
> Fix this by just leaving the inode dirty and moving on to inspect the other
> blockdev inodes on sb->s_io.
>
> (This is a little inefficient: an alternative is to leave dirtied
> memory-backed inodes on inode_in_use, so nobody ever even considers them
> for writeout.  But that introduces an inconsistency and is a bit kludgey).
>
>
>
>  fs/fs-writeback.c |   15 ++++++++++++++-
>  1 files changed, 14 insertions(+), 1 deletion(-)
>
> diff -puN fs/fs-writeback.c~writeback-memory-backed-fix fs/fs-writeback.c
> --- 25/fs/fs-writeback.c~writeback-memory-backed-fix	2003-06-12
> 23:12:28.000000000 -0700 +++ 25-akpm/fs/fs-writeback.c	2003-06-12
> 23:14:07.000000000 -0700
> @@ -260,8 +260,21 @@ sync_sb_inodes(struct super_block *sb, s
>  		struct address_space *mapping = inode->i_mapping;
>  		struct backing_dev_info *bdi = mapping->backing_dev_info;
>
> -		if (bdi->memory_backed)
> +		if (bdi->memory_backed) {
> +			if (sb == blockdev_superblock) {
> +				/*
> +				 * Dirty memory-backed blockdev: the ramdisk
> +				 * driver does this.
> +				 */
> +				list_move(&inode->i_list, &sb->s_dirty);
> +				continue;
> +			}
> +			/*
> +			 * Assume that all inodes on this superblock are memory
> +			 * backed.  Skip the superblock.
> +			 */
>  			break;
> +		}
>
>  		if (wbc->nonblocking && bdi_write_congested(bdi)) {
>  			wbc->encountered_congestion = 1;
>
> _

- -- 
Coincidences are spiritual puns.
		-- G.K. Chesterton
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