Bug 481371

Summary: PG_error bit is never cleared, even when a fresh I/O to the page succeeds
Product: Red Hat Enterprise Linux 4 Reporter: Jeff Moyer <jmoyer>
Component: kernelAssignee: Rik van Riel <riel>
Status: CLOSED ERRATA QA Contact: Gris Ge <fge>
Severity: medium Docs Contact:
Priority: low    
Version: 4.8CC: bmarzins, dhoward, fge, riel, vgoyal
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
: 590763 (view as bug list) Environment:
Last Closed: 2011-02-16 16:06:16 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 589295, 590763    
Attachments:
Description Flags
Clear PG_error before issuing a readpage none

Description Jeff Moyer 2009-01-23 19:41:22 UTC 
Description of problem:

The problem is that, once you set the PG_error bit for the page cache page, a regular read on the device file will always and forever see an
error.  I proposed this patch upstream:
  http://lkml.org/lkml/2009/1/23/288

A simple way around the problem is to mmap the device and read from the
locations that are giving I/O errors (but that's hardly acceptable!).


Version-Release number of selected component (if applicable):
2.4.9-78.30.EL

How reproducible:
100%

Steps to Reproduce:
1. Incur an I/O error by, for example, failing all paths to a device and trying to read from it.
2. restore the device to working order
3. try to read the failed sectors
  
Actual results:
EIO

Expected results:
Read succeeds

Additional info:
See also bug 454872 for one instance where this was seen.
Comment 1 Jeff Moyer 2009-01-23 21:33:18 UTC 
Created attachment 329884 [details]
Clear PG_error before issuing a readpage

This should fix the problem.
Comment 2 Ben Marzinski 2009-01-23 22:46:42 UTC 
I tested both RHEL5 and upstream. This bug also exists in both to them.
Comment 3 RHEL Program Management 2009-06-05 13:47:00 UTC 
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.
Comment 4 Vivek Goyal 2010-09-23 13:01:51 UTC 
Committed in 89.37.EL . RPMS are available at http://people.redhat.com/vgoyal/rhel4/
Comment 9 Gris Ge 2011-01-26 07:40:25 UTC 
Reproduced this problem on kernel-2.6.9-78.30.EL
This is the steps for testing on HBA multipath device:
=================================
mkfs.ext3 /dev/mapper/mpath0

mount /dev/mapper/mpath0 /mnt
echo "test" > /mnt/testfile
umount /mnt
sync
echo 3 > /proc/sys/vm/drop_caches
mount /dev/mapper/mpath0 /mnt
ls /mnt
#bring FC link down from switch side.
strace dd if=/mnt/testfile
#got read(0, 0x50b000, 512)                  = -1 EIO (Input/output error)
#bring FC link up from switch side.
#mulitpath show link was revived.
strace dd if=/mnt/testfile
#still the same error.

kernel-2.6.9-96.EL fixed this issue.
Verified.
Comment 10 errata-xmlrpc 2011-02-16 16:06:16 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0263.html