[PATCH] f2fs: hurry up to issue discard after io interruption

[Chao Yu]

Once we encounter I/O interruption during issuing discards, we will delay
long time before next round, but if system status is I/O idle during the
time, it may loses opportunity to issue discards. So this patch changes
to hurry up to issue discard after io interruption.

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
 fs/f2fs/segment.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 7fd742f747ce..3ee2236fc091 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1062,6 +1062,7 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, bool issue_cond)
 	struct blk_plug plug;
 	int iter = 0, issued = 0;
 	int i;
+	bool io_interrupted = false;
 
 	mutex_lock(&dcc->cmd_lock);
 	f2fs_bug_on(sbi,
@@ -1083,10 +1084,19 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, bool issue_cond)
 				continue;
 			}
 
-			if (!issue_cond || is_idle(sbi)) {
+			if (!issue_cond) {
+				__submit_discard_cmd(sbi, dc);
 				issued++;
+				continue;
+			}
+
+			if (is_idle(sbi)) {
 				__submit_discard_cmd(sbi, dc);
+				issued++;
+			} else {
+				io_interrupted = true;
 			}
+
 			if (issue_cond && iter++ > DISCARD_ISSUE_RATE)
 				goto out;
 		}
@@ -1097,6 +1107,9 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, bool issue_cond)
 	blk_finish_plug(&plug);
 	mutex_unlock(&dcc->cmd_lock);
 
+	if (!issued && io_interrupted)
+		issued = -1;
+
 	return issued;
 }
 
-- 
2.13.1.388.g69e6b9b4f4a9