1. 23 Aug, 2011 1 commit
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  3. 21 Aug, 2011 4 commits
  4. 20 Aug, 2011 4 commits
  5. 19 Aug, 2011 1 commit
    • Jiaying Zhang's avatar
      ext4: flush any pending end_io requests before DIO reads w/dioread_nolock · dccaf33f
      Jiaying Zhang authored
      There is a race between ext4 buffer write and direct_IO read with
      dioread_nolock mount option enabled. The problem is that we clear
      PageWriteback flag during end_io time but will do
      uninitialized-to-initialized extent conversion later with dioread_nolock.
      If an O_direct read request comes in during this period, ext4 will return
      zero instead of the recently written data.
      
      This patch checks whether there are any pending uninitialized-to-initialized
      extent conversion requests before doing O_direct read to close the race.
      Note that this is just a bandaid fix. The fundamental issue is that we
      clear PageWriteback flag before we really complete an IO, which is
      problem-prone. To fix the fundamental issue, we may need to implement an
      extent tree cache that we can use to look up pending to-be-converted extents.
      Signed-off-by: default avatarJiaying Zhang <jiayingz@google.com>
      Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      Cc: stable@kernel.org
      dccaf33f