title: Reason for ubi filesystem corruption
body: <p>I have used ubi filesystem and mtd subsystem to work on the top of NAND flash.
  It was working fine.</p>
  
  <p>But now I'm finding the following errors:</p>
  
  <p>UBI error: ubi_io_read: error -74 while reading 516096 bytes from PEB 2701:8192, read 516096 bytes</p>
  
  <p>end_request: I/O error, dev mtdblock5, sector 49160</p>
  
  <p>what is the reason for those errors which I have mentioned above?
  How to recover from these error?</p>