Re: [f2fs-dev] [PATCH] f2fs: fix deadlock between quota writes and checkpoint

[Chao Yu]

On 2020-7-29 15:02, Jaegeuk Kim wrote:

f2fs_write_data_pages(quota_mapping)
 __f2fs_write_data_pages             f2fs_write_checkpoint
  * blk_start_plug(&plug);
  * add bio in write_io[DATA]
                                      - block_operations
                                      - skip syncing quota by
                                                >DEFAULT_RETRY_QUOTA_FLUSH_COUNT
                                      - down_write(&sbi->node_write);
  - f2fs_write_single_data_page

After commit 79963d967b49 ("f2fs: shrink node_write lock coverage"),
node_write lock was moved to f2fs_write_single_data_page() and
f2fs_write_compressed_pages().

So it needs to update the callstack.

- down_write(node_write)

Otherwise it looks good to me.

Reviewed-by: Chao Yu <yuch...@huawei.com>

Thanks,

    - f2fs_do_write_data_page
      - f2fs_outplace_write_data
        - do_write_page
           - f2fs_allocate_data_block
            - down_write(node_write)
                                      - f2fs_wait_on_all_pages(F2FS_WB_CP_DATA);

Signed-off-by: Daeho Jeong <daehoje...@google.com>
Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
---
 fs/f2fs/checkpoint.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 8c782d3f324f0..99c8061da55b9 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1269,6 +1269,8 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int 
type)
                if (type == F2FS_DIRTY_META)
                        f2fs_sync_meta_pages(sbi, META, LONG_MAX,
                                                        FS_CP_META_IO);
+               else if (type == F2FS_WB_CP_DATA)
+                       f2fs_submit_merged_write(sbi, DATA);
                io_schedule_timeout(DEFAULT_IO_TIMEOUT);
        }
        finish_wait(&sbi->cp_wait, &wait);