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* removable media support on 2.6.x
@ 2004-06-04 15:11 Jinu M.
  2004-06-05  4:47 ` Andrew Morton
  0 siblings, 1 reply; 5+ messages in thread
From: Jinu M. @ 2004-06-04 15:11 UTC (permalink / raw)
  To: linux-kernel; +Cc: kernelnewbies, Surendra I.

Hi All,

We are developing a storage driver (block driver) on 2.6.x kernel. The 
hardware we are using supports media removal on the fly. We are facing
some problem when the media is removed while the disk is mounted. The
system freezes and the module count never goes to zero.

This is what we do when the disk is removed on the fly.

disk_removed(...)
{
	/* invalidate disk */
	if(gDisk->bdev) {
		invalidate_bdev(gDisk->bdev, 1);
		bdput(gDisk->bdev);
	}

	/* indicates that no disk present */
	set_capacity(gDisk->gd, 0);

	/* cleanup gendisk */
	del_gendisk(gDisk->gd);
	put_disk(gDisk->gd);

	/* clean up blkqueue */
	blk_cleanup_queue(gDisk->blkqueue);
}

disk_removed() is called from the workqueue that is initiated from the
tasklet()<=isr() on card removal.

We guess invalidate_bdev() is the culprit ;) but would like to know
from you all if we are doing some mistake. Is there something missing
or something wrong in the way we are trying to provide removable media
support?

Thanks in advance,

-Jinu

^ permalink raw reply	[flat|nested] 5+ messages in thread
* RE: removable media support on 2.6.x
@ 2004-06-05  5:08 Jinu M.
  2004-06-05 10:51 ` Matthias Urlichs
  0 siblings, 1 reply; 5+ messages in thread
From: Jinu M. @ 2004-06-05  5:08 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-kernel, kernelnewbies, Surendra I.

> 
> afaik we don't really support hot unplug like this.
> 
> Changes were made a few months ago (make the VFS use file->f_mapping
> rather
> than file->f_dentry->d_inode->i_mapping) which set some of the
> pieces in
> place but I think there's a way to go yet.
> 
> umm, the general idea is that when the disk vanishes your driver
> should
> then return -EIO for all future I/O requests.  The block_device, the
> queue,
> the inode and all that stuff remains in-core.

What we do with our 2.4 version of the driver is something on this
lines. When the media is removed we invalidate the buffers and then
set the card absent bit. Now on when read/write requests arrive we
return error status to the file system since card is absent. This worked
for 2.4.x.

Is there some existing driver which addresses removable media on 2.6.x
Kernel? I would like to see how it addresses this.. then I will have
a better idea to address it with the kernel support we have now.

-Jinu

^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2004-06-05 21:34 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-06-04 15:11 removable media support on 2.6.x Jinu M.
2004-06-05  4:47 ` Andrew Morton
2004-06-05 21:33   ` modprobing ACPI(?) module gives oops (2.6.7-rc2-mm2) Grzegorz Kulewski
2004-06-05  5:08 removable media support on 2.6.x Jinu M.
2004-06-05 10:51 ` Matthias Urlichs

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