JFFS2_WBUF_VERIFY patch clarification (RESENT)

Sankara Narayanan Balasubramanian sankara.narayanan at tridentmicro.com
Wed Mar 23 01:40:13 EDT 2011


We are using JFFS2 as part of our linux kernel v2.6.18 in our product. We are using JFFS2 file system on top of the MTD Driver for NAND Flash (SLC Nand flash). We observe the problem during our long duration file write tests (endurance tests) that occasionally the data written through the fwrite function call is not present in the flash. 

We checked the latest kernel sources (2.6.37) and observed a similar problem being resolved through the JFFS2_WBUF_VERIFY patch. We took only that patch (implementation into our wbuf.c file) and we observe that the problem is resolved. We request you to provide the feedback for the following.

1.	Can this patch be taken as a stand-alone patch into our existing JFFS2 as part of linux 2.6.18 release.
2.	What is the exact behavior of the patch? We observe that the patch ensures that the jffs2_wbuf_recovery is called once more if the first attempt to verify fails. How does it ensure that the data is written into the flash properly? 
3.	Are there any chances / known instances that the patch may fail (if the second attempt to recovery also fail)?

Pls note that we cannot move to the latest version of kernel as this product is in maintenance phase.

With regards,
Sankara Narayanan B

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