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 <[email protected]>
---
Patch against 2.6.32-rc7
Revised to handle both sync_fs and put_super updating superblock.
--- 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);
+ }
+
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;
}
--
> 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 <[email protected]>
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 <[email protected]>
SuSE CR Labs
On Thu, 19 Nov 2009 16:19:53 +0100
Jan Kara <[email protected]> wrote:
> > + 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 :)
This code mirrors ext4_commit_super, why should ext2 be any different?
On Thu 19-11-09 10:13:17, Stephen Hemminger wrote:
> On Thu, 19 Nov 2009 16:19:53 +0100
> Jan Kara <[email protected]> wrote:
>
> > > + 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 :)
>
> This code mirrors ext4_commit_super, why should ext2 be any different?
OK, my remark was mostly about the comment which is different in ext4 ;).
I'll just fixup the comment and merge the patch. Thanks.
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR