releases/4.17.12/f2fs-avoid-fsync-failure-caused-by-eagain-in-writepage.patch

   1 From foo@baz Sat Jul 28 10:14:30 CEST 2018
   2 From: Jaegeuk Kim <jaegeuk@kernel.org>
   3 Date: Thu, 3 May 2018 23:26:02 -0700
   4 Subject: f2fs: avoid fsync() failure caused by EAGAIN in writepage()
   5
   6 From: Jaegeuk Kim <jaegeuk@kernel.org>
   7
   8 [ Upstream commit 5b19d284f5195a925dd015a6397bfce184097378 ]
   9
  10 pageout() in MM traslates EAGAIN, so calls handle_write_error()
  11  -> mapping_set_error() -> set_bit(AS_EIO, ...).
  12  file_write_and_wait_range() will see EIO error, which is critical
  13  to return value of fsync() followed by atomic_write failure to user.
  14
  15 Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
  16 Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
  17 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  18 ---
  19  fs/f2fs/data.c |    8 +++++++-
  20  1 file changed, 7 insertions(+), 1 deletion(-)
  21
  22 --- a/fs/f2fs/data.c
  23 +++ b/fs/f2fs/data.c
  24 @@ -1848,7 +1848,13 @@ out:
  25
  26  redirty_out:
  27         redirty_page_for_writepage(wbc, page);
  28 -       if (!err)
  29 +       /*
  30 +        * pageout() in MM traslates EAGAIN, so calls handle_write_error()
  31 +        * -> mapping_set_error() -> set_bit(AS_EIO, ...).
  32 +        * file_write_and_wait_range() will see EIO error, which is critical
  33 +        * to return value of fsync() followed by atomic_write failure to user.
  34 +        */
  35 +       if (!err || wbc->for_reclaim)
  36                 return AOP_WRITEPAGE_ACTIVATE;
  37         unlock_page(page);
  38         return err;