Re: [PATCH] MMC: Add 400ms to CAFE SD controller resume path

[Pierre Ossman <pierre@ossman.eu>]

[-- Attachment #1: Type: text/plain, Size: 1240 bytes --]

On Thu, 4 Jun 2009 23:33:49 +0000
Deepak Saxena <dsaxena@plexity.net> wrote:

> 
> The request is not ending up in the queue of the new device.  If I 
> recall correctyl What is happening is that userspace does an unmount on the 
> old device when it receives the notification that it is gone (since it is not 
> redected and a new entry is created). By the time that unmount is called, the 
> various data structures for the device has been zeroed out but the various 
> operation pointers are !NULL, so when we go back to write the superblock for 
> the mounted partition, we overwrite the device's partition table as the
> partition offset is now 0. The main issue here is that the kernel is allowing 
> an I/O to a device that is technically still there but not from the kernel's
> POV.

But if the device is not there from the kernel's POV then it should be
impossible to write to it. It seems this is a kernel bug though. See
this thread:

http://marc.info/?t=124413860500006&r=1&w=2

Rgds
-- 
     -- Pierre Ossman

  WARNING: This correspondence is being monitored by the
  Swedish government. Make sure your server uses encryption
  for SMTP traffic and consider using PGP for end-to-end
  encryption.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 198 bytes --]