f2fs: flush stale issued discard candidates

Sometimes, I could observe # of issuing_discard to be 1 which blocks background
jobs due to is_idle()=false.
The only way to get out of it was to trigger gc_urgent. This patch avoids that
by checking any candidates as done in the list.

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

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 0f7a92b..d9a3345 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1652,6 +1652,10 @@ static int issue_discard_thread(void *data)
                if (dcc->discard_wake)
                        dcc->discard_wake = 0;
 
+               /* clean up pending candidates before going to sleep */
+               if (atomic_read(&dcc->queued_discard))
+                       __wait_all_discard_cmd(sbi, NULL);
+
                if (try_to_freeze())
                        continue;
                if (f2fs_readonly(sbi->sb))