Shutdown preventing umount

[Andi Kleen <andi@firstfloor.org>]

Hi,

I had a cable problem on a USB connected XFS file system, triggering 
some IO errors, and the result was that any access to the mount point
resulted in EIO. This prevented unmounting the file system to recover
from the problem. 

I also tried xfs_io with shutdown -f, but it had the same problem
because xfs_io couldn't access anything on the file system.

How is that supposed to work? Having to reboot just to recover
from IO errors doesn't seem to be very available.

I don't think shutdown should prevent unmounting.

From googling I found some old RHEL bugzilla that such a problem
was fixed in some RHEL release. Is that a regression? 

This was on a 5.4.10 kernel.

I got lots of:

 XFS (...): metadata I/O error in "xfs_trans_read_buf_map" at daddr
 0x4a620288 len 8 error 5

Then some

XFS (...): writeback error on sector 7372099184

And finally:

XFS (...): log I/O error -5
 XFS (...): xfs_do_force_shutdown(0x2)
called from line 1250 of file fs/xfs/xfs_log.c. Return address =
00000000f7956130
XFS (...): Log I/O Error Detected.
Shutting down filesystem
XFS (...): Please unmount the filesystem
and rectify the problem(s)

(very funny XFS!)

XFS (...): log I/O error -5

scsi 7:0:0:0: rejecting I/O to dead device

-Andi