releases/5.0.7/f2fs-fix-to-data-block-override-node-segment-by-mist.patch

   1 From f22ff541a11ffc6c525020014689054fe7d662d1 Mon Sep 17 00:00:00 2001
   2 From: zhengliang <zhengliang6@huawei.com>
   3 Date: Mon, 4 Mar 2019 09:32:25 +0800
   4 Subject: f2fs: fix to data block override node segment by mistake
   5
   6 [ Upstream commit a0770e13c8da83bdb64738c0209ab02dd3cfff8b ]
   7
   8 v4: Rearrange the previous three versions.
   9
  10 The following scenario could lead to data block override by mistake.
  11
  12 TASK A            |  TASK kworker                                            |     TASK B                                            |       TASK C
  13                   |                                                          |                                                       |
  14 open              |                                                          |                                                       |
  15 write             |                                                          |                                                       |
  16 close             |                                                          |                                                       |
  17                   |  f2fs_write_data_pages                                   |                                                       |
  18                   |    f2fs_write_cache_pages                                |                                                       |
  19                   |      f2fs_outplace_write_data                            |                                                       |
  20                   |        f2fs_allocate_data_block (get block in seg S,     |                                                       |
  21                   |                                  S is full, and only     |                                                       |
  22                   |                                  have this valid data    |                                                       |
  23                   |                                  block)                  |                                                       |
  24                   |          allocate_segment                                |                                                       |
  25                   |          locate_dirty_segment (mark S as PRE)            |                                                       |
  26                   |        f2fs_submit_page_write (submit but is not         |                                                       |
  27                   |                                written on dev)           |                                                       |
  28 unlink            |                                                          |                                                       |
  29  iput_final       |                                                          |                                                       |
  30   f2fs_drop_inode |                                                          |                                                       |
  31     f2fs_truncate |                                                          |                                                       |
  32  (not evict)      |                                                          |                                                       |
  33                   |                                                          | write_checkpoint                                      |
  34                   |                                                          |  flush merged bio but not wait file data writeback    |
  35                   |                                                          |  set_prefree_as_free (mark S as FREE)                 |
  36                   |                                                          |                                                       | update NODE/DATA
  37                   |                                                          |                                                       | allocate_segment (select S)
  38                   |     writeback done                                       |                                                       |
  39
  40 So we need to guarantee io complete before truncate inode in f2fs_drop_inode.
  41
  42 Reviewed-by: Chao Yu <yuchao0@huawei.com>
  43 Signed-off-by: Zheng Liang <zhengliang6@huawei.com>
  44 Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
  45 Signed-off-by: Sasha Levin <sashal@kernel.org>
  46 ---
  47  fs/f2fs/super.c | 4 ++++
  48  1 file changed, 4 insertions(+)
  49
  50 diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
  51 index c46a1d4318d4..93d7427d8883 100644
  52 --- a/fs/f2fs/super.c
  53 +++ b/fs/f2fs/super.c
  54 @@ -915,6 +915,10 @@ static int f2fs_drop_inode(struct inode *inode)
  55                         sb_start_intwrite(inode->i_sb);
  56                         f2fs_i_size_write(inode, 0);
  57
  58 +                       f2fs_submit_merged_write_cond(F2FS_I_SB(inode),
  59 +                                       inode, NULL, 0, DATA);
  60 +                       truncate_inode_pages_final(inode->i_mapping);
  61 +
  62                         if (F2FS_HAS_BLOCKS(inode))
  63                                 f2fs_truncate(inode);
  64
  65 --
  66 2.19.1
  67