1. 21 5月, 2013 1 次提交
    • A
      NFSv4.1 Fix a pNFS session draining deadlock · 774d5f14
      Andy Adamson 提交于
      On a CB_RECALL the callback service thread flushes the inode using
      filemap_flush prior to scheduling the state manager thread to return the
      delegation. When pNFS is used and I/O has not yet gone to the data server
      servicing the inode, a LAYOUTGET can preceed the I/O. Unlike the async
      filemap_flush call, the LAYOUTGET must proceed to completion.
      
      If the state manager starts to recover data while the inode flush is sending
      the LAYOUTGET, a deadlock occurs as the callback service thread holds the
      single callback session slot until the flushing is done which blocks the state
      manager thread, and the state manager thread has set the session draining bit
      which puts the inode flush LAYOUTGET RPC to sleep on the forechannel slot
      table waitq.
      
      Separate the draining of the back channel from the draining of the fore channel
      by moving the NFS4_SESSION_DRAINING bit from session scope into the fore
      and back slot tables.  Drain the back channel first allowing the LAYOUTGET
      call to proceed (and fail) so the callback service thread frees the callback
      slot. Then proceed with draining the forechannel.
      Signed-off-by: NAndy Adamson <andros@netapp.com>
      Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
      774d5f14
  2. 16 12月, 2012 2 次提交
  3. 06 12月, 2012 5 次提交