Re: Weird I/O errors with USB hard drive not remounting filesystemreadonly

From: Alan Stern
Date: Mon Nov 23 2009 - 13:20:38 EST


On Mon, 23 Nov 2009, Jan Kara wrote:

> On Mon 23-11-09 10:06:03, Alan Stern wrote:
> > On Mon, 23 Nov 2009, Jan Kara wrote:
> >
> > > Yeah, from what you write, it looks like USB enclosure is at fault (or it
> > > could still be your USB controller but I doubt it). It's still a bit
> > > bothering that the error reported by the drive was not properly propagated
> > > up to VFS. Either it's some block layer retry/ignore magic that I missed or
> > > we ignore errors from block layer in some place.
> >
> > Is there any interest in tracking this down? It's not hard to find out
> > what low-level errors are being reported and to generate them on demand
> > with an emulated USB disk drive.
> Well, if you could provide me with the patch, I could try to track down
> why the errors aren't propagated... It would be interesting because if it's
> not some retry logic in block layer, it's a bug in VFS ;).

I can't provide a patch without first knowing what the errors are. The
way to find out is to use usbmon. See Documentation/usb/usbmon.txt for
instructions.

Alan Stern

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