[PATCH] add I/O error uevent for block devices

[PATCH] add I/O error uevent for block devices

[Kay Sievers]

For HAL we want to get notified about I/O errors of block devices.
This is especially useful for devices we are unable to poll and
therefore can't know if something goes wrong here.

Signed-off-by: David Zeuthen <david@fubar.dk>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>

===== fs/buffer.c 1.270 vs edited =====
--- 1.270/fs/buffer.c	2005-01-21 06:02:13 +01:00
+++ edited/fs/buffer.c	2005-02-17 22:56:05 +01:00
@@ -105,6 +105,7 @@ static void buffer_io_error(struct buffe
 	printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
 			bdevname(bh->b_bdev, b),
 			(unsigned long long)bh->b_blocknr);
+	kobject_uevent(&bh->b_bdev->bd_disk->kobj, KOBJ_IO_ERROR, NULL);
 }
 
 /*
@@ -550,7 +551,8 @@ static void end_buffer_async_read(struct
 		set_buffer_uptodate(bh);
 	} else {
 		clear_buffer_uptodate(bh);
-		buffer_io_error(bh);
+		if (printk_ratelimit())
+			buffer_io_error(bh);
 		SetPageError(page);
 	}
 
===== include/linux/kobject_uevent.h 1.6 vs edited =====
--- 1.6/include/linux/kobject_uevent.h	2004-11-08 20:43:30 +01:00
+++ edited/include/linux/kobject_uevent.h	2005-02-17 23:10:05 +01:00
@@ -29,6 +29,7 @@ enum kobject_action {
 	KOBJ_UMOUNT	= (__force kobject_action_t) 0x05,	/* umount event for block devices */
 	KOBJ_OFFLINE	= (__force kobject_action_t) 0x06,	/* offline event for hotplug devices */
 	KOBJ_ONLINE	= (__force kobject_action_t) 0x07,	/* online event for hotplug devices */
+	KOBJ_IO_ERROR	= (__force kobject_action_t) 0x08,	/* I/O error for devices */
 };
 
 
===== lib/kobject_uevent.c 1.18 vs edited =====
--- 1.18/lib/kobject_uevent.c	2005-01-08 06:44:13 +01:00
+++ edited/lib/kobject_uevent.c	2005-02-17 22:52:03 +01:00
@@ -44,6 +44,8 @@ static char *action_to_string(enum kobje
 		return "offline";
 	case KOBJ_ONLINE:
 		return "online";
+	case KOBJ_IO_ERROR:
+		return "io_error";
 	default:
 		return NULL;
 	}

Re: [PATCH] add I/O error uevent for block devices

[Andrew Morton]

Kay Sievers <kay.sievers@vrfy.org> wrote:
>
> For HAL we want to get notified about I/O errors of block devices.
>  This is especially useful for devices we are unable to poll and
>  therefore can't know if something goes wrong here.
> 
>  Signed-off-by: David Zeuthen <david@fubar.dk>
>  Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
> 
>  ===== fs/buffer.c 1.270 vs edited =====
>  --- 1.270/fs/buffer.c	2005-01-21 06:02:13 +01:00
>  +++ edited/fs/buffer.c	2005-02-17 22:56:05 +01:00
>  @@ -105,6 +105,7 @@ static void buffer_io_error(struct buffe
>   	printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
>   			bdevname(bh->b_bdev, b),
>   			(unsigned long long)bh->b_blocknr);
>  +	kobject_uevent(&bh->b_bdev->bd_disk->kobj, KOBJ_IO_ERROR, NULL);
>   }

- buffer_io_error() is called from interrupt context, and
  kobject_uevent() does multiple GFP_KERNEL allocations.  You'll need to
  use kobject_uevent_atomic().

- the prink_ratelimit() fix in end_buffer_async_read() should be a
  separate patch, really.  I'll fix that up.

- there are numerous other places where an I/O error can be detected:
  grep the tree for b_end_io and bio_end_io.

Re: [PATCH] add I/O error uevent for block devices

[Kay Sievers]

On Fri, Feb 18, 2005 at 01:46:21AM -0800, Andrew Morton wrote:
> Kay Sievers <kay.sievers@vrfy.org> wrote:
> >
> > For HAL we want to get notified about I/O errors of block devices.
> >  This is especially useful for devices we are unable to poll and
> >  therefore can't know if something goes wrong here.

> - buffer_io_error() is called from interrupt context, and
>   kobject_uevent() does multiple GFP_KERNEL allocations.  You'll need to
>   use kobject_uevent_atomic().

Fixed.

> - the prink_ratelimit() fix in end_buffer_async_read() should be a
>   separate patch, really.  I'll fix that up.

Removed that part.

> - there are numerous other places where an I/O error can be detected:
>   grep the tree for b_end_io and bio_end_io.

You mean the mmap and direct-io stuff?

Thanks,
Kay

-----
For HAL we want to get notified about I/O errors of block devices.
This is especially useful for devices we are unable to poll and
therefore can't know if something goes wrong here.

Signed-off-by: David Zeuthen <david@fubar.dk>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>

===== fs/buffer.c 1.270 vs edited =====
--- 1.270/fs/buffer.c	2005-01-21 06:02:13 +01:00
+++ edited/fs/buffer.c	2005-02-18 13:00:18 +01:00
@@ -105,6 +105,7 @@ static void buffer_io_error(struct buffe
 	printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
 			bdevname(bh->b_bdev, b),
 			(unsigned long long)bh->b_blocknr);
+	kobject_uevent_atomic(&bh->b_bdev->bd_disk->kobj, KOBJ_IO_ERROR, NULL);
 }
 
 /*
===== include/linux/kobject_uevent.h 1.6 vs edited =====
--- 1.6/include/linux/kobject_uevent.h	2004-11-08 20:43:30 +01:00
+++ edited/include/linux/kobject_uevent.h	2005-02-18 12:59:18 +01:00
@@ -29,6 +29,7 @@ enum kobject_action {
 	KOBJ_UMOUNT	= (__force kobject_action_t) 0x05,	/* umount event for block devices */
 	KOBJ_OFFLINE	= (__force kobject_action_t) 0x06,	/* offline event for hotplug devices */
 	KOBJ_ONLINE	= (__force kobject_action_t) 0x07,	/* online event for hotplug devices */
+	KOBJ_IO_ERROR	= (__force kobject_action_t) 0x08,	/* I/O error for devices */
 };
 
 
===== lib/kobject_uevent.c 1.18 vs edited =====
--- 1.18/lib/kobject_uevent.c	2005-01-08 06:44:13 +01:00
+++ edited/lib/kobject_uevent.c	2005-02-18 12:59:18 +01:00
@@ -44,6 +44,8 @@ static char *action_to_string(enum kobje
 		return "offline";
 	case KOBJ_ONLINE:
 		return "online";
+	case KOBJ_IO_ERROR:
+		return "io_error";
 	default:
 		return NULL;
 	}

Re: [PATCH] add I/O error uevent for block devices

[Andrew Morton]

Kay Sievers <kay.sievers@vrfy.org> wrote:
>
>  > - there are numerous other places where an I/O error can be detected:
>  >   grep the tree for b_end_io and bio_end_io.
> 
>  You mean the mmap and direct-io stuff?

direct-io, certainly.  Also reiserfs, xfs, ntfs, ext3, jfs and possibly md
have their own I/O completion handlers.

Re: [PATCH] add I/O error uevent for block devices

[Kay Sievers]

On Fri, Feb 18, 2005 at 11:02:32AM -0800, Andrew Morton wrote:
> Kay Sievers <kay.sievers@vrfy.org> wrote:
> >
> >  > - there are numerous other places where an I/O error can be detected:
> >  >   grep the tree for b_end_io and bio_end_io.
> > 
> >  You mean the mmap and direct-io stuff?
> 
> direct-io, certainly.  Also reiserfs, xfs, ntfs, ext3, jfs and possibly md
> have their own I/O completion handlers.

Hmm, ok. Any idea how to propagate errors like this in a saner way? Some of
these places don't even log errors and spreading uevents all over the place
doesn't sounds like the best idea.

Thanks,
Kay

Re: [PATCH] add I/O error uevent for block devices

[Andrew Morton]

Kay Sievers <kay.sievers@vrfy.org> wrote:
>
> On Fri, Feb 18, 2005 at 11:02:32AM -0800, Andrew Morton wrote:
> > Kay Sievers <kay.sievers@vrfy.org> wrote:
> > >
> > >  > - there are numerous other places where an I/O error can be detected:
> > >  >   grep the tree for b_end_io and bio_end_io.
> > > 
> > >  You mean the mmap and direct-io stuff?
> > 
> > direct-io, certainly.  Also reiserfs, xfs, ntfs, ext3, jfs and possibly md
> > have their own I/O completion handlers.
> 
> Hmm, ok. Any idea how to propagate errors like this in a saner way? Some of
> these places don't even log errors and spreading uevents all over the place
> doesn't sounds like the best idea.
> 

I guess you should add some new generic function
handle_block_io_error(bdev, rw, sector) in ll_rw_blk.c and do whatever you
need to do inside that.  Move the ratelimited printk there, too.