Commit 8b107f5b authored Feb 27, 2017 by Jaegeuk Kim

f2fs: avoid to issue redundant discard commands



If segs_per_sec is over 1 like under SMR, previously f2fs issues discard
commands redundantly on the same section, since we didn't move end position
for the previous discard command.

E.g.,

                       start  end
                         |    |
      prefree_bitmap = [01111100111100]

And, after issue discard for this section,
                             end      start
                              |        |
      prefree_bitmap = [01111100111100]

Select this section again by searching from (end + 1),
                             start  end
                                |   |
      prefree_bitmap = [01111100111100]

Fixes: 36abef4e ("f2fs: introduce mode=lfs mount option")
Cc: <stable@vger.kernel.org>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

parent 37e79cd3

fs/f2fs/segment.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1036,6 +1036,8 @@ void clear_prefree_segments(struct f2fs_sb_info sbi, struct cp_control cpc)
		start = start_segno + sbi->segs_per_sec;
		if (start < end)
		goto next;
		else
		end = start - 1;
		}
		mutex_unlock(&dirty_i->seglist_lock);