ext4: Resolve the hang of direct i/o read in handling EXT4_IO_END_UNWRITTEN.
authorTao Ma <boyu.mt@taobao.com>
Sat, 13 Aug 2011 16:30:59 +0000 (12:30 -0400)
committerTheodore Ts'o <tytso@mit.edu>
Sat, 13 Aug 2011 16:30:59 +0000 (12:30 -0400)
commit32c80b32c053dc52712dedac5e4d0aa7c93fc353
tree857375faae2d6c562741d14ed13a1411b197baf5
parent2581fdc810889fdea97689cb62481201d579c796
ext4: Resolve the hang of direct i/o read in handling EXT4_IO_END_UNWRITTEN.

EXT4_IO_END_UNWRITTEN flag set and the increase of i_aiodio_unwritten
should be done simultaneously since ext4_end_io_nolock always clear
the flag and decrease the counter in the same time.

We don't increase i_aiodio_unwritten when setting
EXT4_IO_END_UNWRITTEN so it will go nagative and causes some process
to wait forever.

Part of the patch came from Eric in his e-mail, but it doesn't fix the
problem met by Michael actually.

http://marc.info/?l=linux-ext4&m=131316851417460&w=2

Reported-and-Tested-by: Michael Tokarev<mjt@tls.msk.ru>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
fs/ext4/inode.c
fs/ext4/page-io.c