f2fs: support issuing/waiting discard in range

Fstrim intends to trim invalid blocks of filesystem only with specified
range and granularity, but actually, it will issue all previous cached
discard commands which may be out-of-range and be with unmatched
granularity, it's unneeded.

In order to fix above issues, this patch introduces new helps to support
to issue and wait discard in range and adds a new fstrim_list for tracking
in-flight discard from ->fstrim.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 106 insertions, 21 deletions

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index d5bad5aedded..a0a0a887fc31 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -873,9 +873,11 @@ void __check_sit_bitmap(struct f2fs_sb_info *sbi,
 
 /* this function is copied from blkdev_issue_discard from block/blk-lib.c */
 static void __submit_discard_cmd(struct f2fs_sb_info *sbi,
-				struct discard_cmd *dc)
+				struct discard_cmd *dc, bool fstrim)
 {
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct list_head *wait_list = fstrim ? &(dcc->fstrim_list) :
+							&(dcc->wait_list);
 	struct bio *bio = NULL;
 
 	if (dc->state != D_PREP)
@@ -897,7 +899,7 @@ static void __submit_discard_cmd(struct f2fs_sb_info *sbi,
 			bio->bi_end_io = f2fs_submit_discard_endio;
 			bio->bi_opf |= REQ_SYNC;
 			submit_bio(bio);
-			list_move_tail(&dc->list, &dcc->wait_list);
+			list_move_tail(&dc->list, wait_list);
 			__check_sit_bitmap(sbi, dc->start, dc->start + dc->len);
 
 			f2fs_update_iostat(sbi, FS_DISCARD, 1);
@@ -1082,6 +1084,68 @@ static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
 	return 0;
 }
 
+static void __issue_discard_cmd_range(struct f2fs_sb_info *sbi,
+					unsigned int start, unsigned int end,
+					unsigned int granularity)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
+	struct rb_node **insert_p = NULL, *insert_parent = NULL;
+	struct discard_cmd *dc;
+	struct blk_plug plug;
+	int issued;
+
+next:
+	issued = 0;
+
+	mutex_lock(&dcc->cmd_lock);
+	f2fs_bug_on(sbi, !__check_rb_tree_consistence(sbi, &dcc->root));
+
+	dc = (struct discard_cmd *)__lookup_rb_tree_ret(&dcc->root,
+					NULL, start,
+					(struct rb_entry **)&prev_dc,
+					(struct rb_entry **)&next_dc,
+					&insert_p, &insert_parent, true);
+	if (!dc)
+		dc = next_dc;
+
+	blk_start_plug(&plug);
+
+	while (dc && dc->lstart <= end) {
+		struct rb_node *node;
+
+		if (dc->len < granularity)
+			goto skip;
+
+		if (dc->state != D_PREP) {
+			list_move_tail(&dc->list, &dcc->fstrim_list);
+			goto skip;
+		}
+
+		__submit_discard_cmd(sbi, dc, true);
+
+		if (++issued >= DISCARD_ISSUE_RATE) {
+			start = dc->lstart + dc->len;
+
+			blk_finish_plug(&plug);
+			mutex_unlock(&dcc->cmd_lock);
+
+			schedule();
+
+			goto next;
+		}
+skip:
+		node = rb_next(&dc->rb_node);
+		dc = rb_entry_safe(node, struct discard_cmd, rb_node);
+
+		if (fatal_signal_pending(current))
+			break;
+	}
+
+	blk_finish_plug(&plug);
+	mutex_unlock(&dcc->cmd_lock);
+}
+
 static int __issue_discard_cmd(struct f2fs_sb_info *sbi, bool issue_cond)
 {
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
@@ -1104,22 +1168,19 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, bool issue_cond)
 
 			/* Hurry up to finish fstrim */
 			if (dcc->pend_list_tag[i] & P_TRIM) {
-				__submit_discard_cmd(sbi, dc);
+				__submit_discard_cmd(sbi, dc, false);
 				issued++;
-
-				if (fatal_signal_pending(current))
-					break;
 				continue;
 			}
 
 			if (!issue_cond) {
-				__submit_discard_cmd(sbi, dc);
+				__submit_discard_cmd(sbi, dc, false);
 				issued++;
 				continue;
 			}
 
 			if (is_idle(sbi)) {
-				__submit_discard_cmd(sbi, dc);
+				__submit_discard_cmd(sbi, dc, false);
 				issued++;
 			} else {
 				io_interrupted = true;
@@ -1173,10 +1234,14 @@ static void __wait_one_discard_bio(struct f2fs_sb_info *sbi,
 	mutex_unlock(&dcc->cmd_lock);
 }
 
-static void __wait_discard_cmd(struct f2fs_sb_info *sbi, bool wait_cond)
+static void __wait_discard_cmd_range(struct f2fs_sb_info *sbi, bool wait_cond,
+						block_t start, block_t end,
+						unsigned int granularity,
+						bool fstrim)
 {
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
-	struct list_head *wait_list = &(dcc->wait_list);
+	struct list_head *wait_list = fstrim ? &(dcc->fstrim_list) :
+							&(dcc->wait_list);
 	struct discard_cmd *dc, *tmp;
 	bool need_wait;
 
@@ -1185,6 +1250,10 @@ next:
 
 	mutex_lock(&dcc->cmd_lock);
 	list_for_each_entry_safe(dc, tmp, wait_list, list) {
+		if (dc->lstart + dc->len <= start || end <= dc->lstart)
+			continue;
+		if (dc->len < granularity)
+			continue;
 		if (!wait_cond || (dc->state == D_DONE && !dc->ref)) {
 			wait_for_completion_io(&dc->wait);
 			__remove_discard_cmd(sbi, dc);
@@ -1202,6 +1271,11 @@ next:
 	}
 }
 
+static void __wait_all_discard_cmd(struct f2fs_sb_info *sbi, bool wait_cond)
+{
+	__wait_discard_cmd_range(sbi, wait_cond, 0, UINT_MAX, 1, false);
+}
+
 /* This should be covered by global mutex, &sit_i->sentry_lock */
 void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
 {
@@ -1237,12 +1311,12 @@ void stop_discard_thread(struct f2fs_sb_info *sbi)
 	}
 }
 
-/* This comes from f2fs_put_super and f2fs_trim_fs */
-void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi, bool umount)
+/* This comes from f2fs_put_super */
+void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
 {
 	__issue_discard_cmd(sbi, false);
 	__drop_discard_cmd(sbi);
-	__wait_discard_cmd(sbi, !umount);
+	__wait_all_discard_cmd(sbi, false);
 }
 
 static void mark_discard_range_all(struct f2fs_sb_info *sbi)
@@ -1286,7 +1360,7 @@ static int issue_discard_thread(void *data)
 
 		issued = __issue_discard_cmd(sbi, true);
 		if (issued) {
-			__wait_discard_cmd(sbi, true);
+			__wait_all_discard_cmd(sbi, true);
 			wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
 		} else {
 			wait_ms = DEF_MAX_DISCARD_ISSUE_TIME;
@@ -1597,6 +1671,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
 			dcc->pend_list_tag[i] |= P_ACTIVE;
 	}
 	INIT_LIST_HEAD(&dcc->wait_list);
+	INIT_LIST_HEAD(&dcc->fstrim_list);
 	mutex_init(&dcc->cmd_lock);
 	atomic_set(&dcc->issued_discard, 0);
 	atomic_set(&dcc->issing_discard, 0);
@@ -2224,7 +2299,8 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 {
 	__u64 start = F2FS_BYTES_TO_BLK(range->start);
 	__u64 end = start + F2FS_BYTES_TO_BLK(range->len) - 1;
-	unsigned int start_segno, end_segno;
+	unsigned int start_segno, end_segno, cur_segno;
+	block_t start_block, end_block;
 	struct cp_control cpc;
 	int err = 0;
 
@@ -2245,12 +2321,17 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 	start_segno = (start <= MAIN_BLKADDR(sbi)) ? 0 : GET_SEGNO(sbi, start);
 	end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
 						GET_SEGNO(sbi, end);
+
+	start_block = START_BLOCK(sbi, start_segno);
+	end_block = START_BLOCK(sbi, end_segno + 1);
+
 	cpc.reason = CP_DISCARD;
 	cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
 
 	/* do checkpoint to issue discard commands safely */
-	for (; start_segno <= end_segno; start_segno = cpc.trim_end + 1) {
-		cpc.trim_start = start_segno;
+	for (cur_segno = start_segno; cur_segno <= end_segno;
+					cur_segno = cpc.trim_end + 1) {
+		cpc.trim_start = cur_segno;
 
 		if (sbi->discard_blks == 0)
 			break;
@@ -2258,7 +2339,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 			cpc.trim_end = end_segno;
 		else
 			cpc.trim_end = min_t(unsigned int,
-				rounddown(start_segno +
+				rounddown(cur_segno +
 				BATCHED_TRIM_SEGMENTS(sbi),
 				sbi->segs_per_sec) - 1, end_segno);
 
@@ -2270,9 +2351,13 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
 
 		schedule();
 	}
-	/* It's time to issue all the filed discards */
-	mark_discard_range_all(sbi);
-	f2fs_wait_discard_bios(sbi, false);
+
+	start_block = START_BLOCK(sbi, start_segno);
+	end_block = START_BLOCK(sbi, min(cur_segno, end_segno) + 1);
+
+	__issue_discard_cmd_range(sbi, start_block, end_block, cpc.trim_minlen);
+	__wait_discard_cmd_range(sbi, true, start_block, end_block,
+						cpc.trim_minlen, true);
 out:
 	range->len = F2FS_BLK_TO_BYTES(cpc.trimmed);
 	return err;