Hi James and linux-scsi community,
Please let us your comments on the patch (community_aac24702.patch) we submitted on December 21, 2009.
Thanks,
Narasimha Reddy
-----Original Message-----
From: Penchala Narasimha Reddy Chilakala, ERS-HCLTech
Sent: Monday, December 21, 2009 6:39 PM
To: 'linux-scsi@xxxxxxxxxxxxxxx'; 'James Bottomley'
Cc: ServeRAID Driver
Subject: [PATCH ] scsi-misc-2.6: File System going into read-only mode
Hi James and linux-scsi community,
I would request you that please review the attached updated patch, which contains the fix for racy issue (which was raised by James) and do the needful to incorporate the patch in up-coming release.
Note: The patch was generated against the "kernel 2.6.33-rc1"
From: Narasimha Reddy <ServeRAIDDriver@xxxxxx>
The attached patch was generated for fixing the following issues. These issues were reported by Cisco, SAP and some other customers as well.
Regarding the testing of fixes:
--------------------------------
These particular problems were reported by Cisco and SAP and customers as well. Cisco reported on RHEL4 U6 and SAP reported on SLES9 SP4 and SLES10 SP2. We added these fixes on RHEL4 U6 and gave a private build to IBM and Cisco. Cisco and IBM tested it for more than 15 days and they reported that they did not see the issue so far. Before the fix, Cisco used to see the issue within 5 days. We generated a patch for SLES9 SP4 and SLES10 SP2 and submitted to Novell. Novell applied the patch and gave a test build to SAP. SAP tested and reported that the build is working properly.
We also tested in our lab using the tools "dishogsync", which is IO stress tool and the tool was provided by Cisco.
Issue1: File System going into read-only mode
---------
Root cause:
-----------
The driver tends to not free the memory (FIB) when the management request exits prematurely. The accumulation of such un-freed memory causes the driver to fail to allocate anymore memory (FIB) and hence return 0x70000 value to the upper layer, which puts the file system into read only mode.
Fix details:
------------
The fix makes sure to free the memory (FIB) even if the request exits prematurely hence ensuring the driver wouldn't run out of memory (FIBs).
Issue2:
-------
False Raid Alert occurs- when the Physical Drives and Logical drives are reported as deleted or added, even though there is no change done on the system
Root cause:
-----------
Driver IOCTLs is signaled with EINTR while waiting on response from the lower layers. Returning "EINTR" will never initiate internal retry.
Fix details:
------------
The issue was fixed by replacing "EINTR" with "ERESTARTSYS" for mid-layer retries.
Signed-off-by: Narasimha Reddy <ServeRAIDDriver@xxxxxx>
Please find the attached patch file "community_aac24701.patch", which has been generated for the issues we fixed and "email" file "community_aac24701.email", which has been generated for the statistics like number of lines inserted and deleted, errors etc.
Regards - Narasimha Reddy
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