]> git.baikalelectronics.ru Git - kernel.git/commit
f2fs: avoid node page to be written twice in gc_node_segment
authorHuang Ying <ying.huang@intel.com>
Sun, 7 Sep 2014 03:05:20 +0000 (11:05 +0800)
committerJaegeuk Kim <jaegeuk@kernel.org>
Tue, 9 Sep 2014 20:15:07 +0000 (13:15 -0700)
commitddb5c0b0043805fca8b48244079ce968ba11678d
treee87eb9e201717999a21e78dabb04cf2748f0dbf3
parent6a7b3c9d6963666671a6ef457086c7c81add3c21
f2fs: avoid node page to be written twice in gc_node_segment

In gc_node_segment, if node page gc is run concurrently with node page
writeback, and check_valid_map and get_node_page run after page locked
and before cur_valid_map is updated as below, it is possible for the
page to be written twice unnecessarily.

sync_node_pages
  try_lock_page
  ...
check_valid_map   f2fs_write_node_page
    ...
    write_node_page
      do_write_page
        allocate_data_block
  ...
  refresh_sit_entry /* update cur_valid_map */
  ...
    ...
    unlock_page
get_node_page
...
set_page_dirty
...
f2fs_put_page
  unlock_page

This can be solved via calling check_valid_map after get_node_page again.

Signed-off-by: Huang, Ying <ying.huang@intel.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
fs/f2fs/gc.c