> This fixes a WARN backtrace in mark_buffer_dirty() that occurs during
> unmount when a USB or floppy device is removed.
> The super block update from a previous operation has marked the buffer
> as in error, and the flag has to be cleared before doing the update.
> (Similar code already exists in ext4).
>
> Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxxxx>
Although I agree with Nick that ultimate solution would be to stop
clearing the uptodate flag, I think the change is fine in principle
as a workaround for warning that only scares people.
> --- a/fs/ext2/super.c 2009-11-17 09:13:21.346375999 -0800
> +++ b/fs/ext2/super.c 2009-11-17 09:14:12.177002522 -0800
> @@ -1099,11 +1099,24 @@ static void ext2_commit_super (struct su
>
> static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
> {
> + struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
> +
> + if (buffer_write_io_error(sbh)) {
> + /*
> + * This happens if USB or floppy device is yanked out.
> + * Maybe user put device back in so warn and update again.
> + */
> + printk(KERN_ERR
> + "EXT2-fs: previous I/O error to superblock detected\n");
> + clear_buffer_write_io_error(sbh);
> + set_buffer_uptodate(sbh);
It's not much about puting the device back. It's really just about
avoiding the warning in mark_buffer_dirty(). So I'd just silently
set_buffer_uptodate and be done with it. For superblock we are darn sure
that in memory copy is the one that has the latest data :)
> + }
> +
> es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
> es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
> es->s_wtime = cpu_to_le32(get_seconds());
> - mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
> - sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
> + mark_buffer_dirty(sbh);
> + sync_dirty_buffer(sbh);
> sb->s_dirt = 0;
> }
Honza
--
Jan Kara <jack@xxxxxxx>
SuSE CR Labs
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