Commit 21cb1d99 authored Mar 11, 2015 by Jaegeuk Kim

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>

parent d6d4f1cb

fs/f2fs/segment.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);