From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Fri, 12 Dec 2014 21:53:41 +0000 (-0800)
Subject: f2fs: fix small discards not to issue redundantly
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d7bc2484b8d4e580370c66ad93c4319225bd104d;p=linux-beck.git

f2fs: fix small discards not to issue redundantly

The ckpt_valid_map and cur_valid_map are synced by seg_info_to_raw_sit.

In the case of small discards, the candidates are selected before sync,
while fitrim selects candidates after sync.

So, for small discards, we need to add candidates only just being obsoleted.

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

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index de9c0700c88e..335418c9a06b 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -525,7 +525,8 @@ static void add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	bool force = (cpc->reason == CP_DISCARD);
 	int i;
 
-	if (!force && !test_opt(sbi, DISCARD))
+	if (!force && (!test_opt(sbi, DISCARD) ||
+			SM_I(sbi)->nr_discards >= SM_I(sbi)->max_discards))
 		return;
 
 	if (force && !se->valid_blocks) {
@@ -553,7 +554,8 @@ static void add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 
 	/* SIT_VBLOCK_MAP_SIZE should be multiple of sizeof(unsigned long) */
 	for (i = 0; i < entries; i++)
-		dmap[i] = ~(cur_map[i] | ckpt_map[i]);
+		dmap[i] = force ? ~ckpt_map[i] :
+				(cur_map[i] ^ ckpt_map[i]) & ckpt_map[i];
 
 	while (force || SM_I(sbi)->nr_discards <= SM_I(sbi)->max_discards) {
 		start = __find_rev_next_bit(dmap, max_blocks, end + 1);
@@ -1759,7 +1761,7 @@ void flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 			se = get_seg_entry(sbi, segno);
 
 			/* add discard candidates */
-			if (SM_I(sbi)->nr_discards < SM_I(sbi)->max_discards) {
+			if (cpc->reason != CP_DISCARD) {
 				cpc->trim_start = segno;
 				add_discard_addrs(sbi, cpc);
 			}