f2fs: fix to cover sentry_lock for block allocation

In the following call stack, f2fs changes the bitmap for dirty segments and # of
dirty sentries without grabbing sit_i->sentry_lock.
This can result in mismatch on bitmap and # of dirty sentries, since if there
are some direct_io operations.

In allocate_data_block,
 - __allocate_new_segments
  - mutex_lock(&curseg->curseg_mutex);
  - s_ops->allocate_segment
   - new_curseg/change_curseg
    - reset_curseg
     - __set_sit_entry_type
      - __mark_sit_entry_dirty
       - set_bit(dirty_sentries_bitmap)
       - dirty_sentries++;

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 3e80bd69d4a07eef2ad3d64662b2a01e3a58a933..eafaf728236ba1ae364480c67c2ec3836114d866 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1167,6 +1167,7 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
        curseg = CURSEG_I(sbi, type);
 
        mutex_lock(&curseg->curseg_mutex);
+       mutex_lock(&sit_i->sentry_lock);
 
        /* direct_io'ed data is aligned to the segment for better performance */
        if (direct_io && curseg->next_blkoff)
@@ -1181,7 +1182,6 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
         */
        __add_sum_entry(sbi, type, sum);
 
-       mutex_lock(&sit_i->sentry_lock);
        __refresh_next_blkoff(sbi, curseg);
 
        stat_inc_block_count(sbi, curseg);