[PATCH v2] f2fs: Don't create discard thread when device not support realtime discard

[Yangtao Li]

From: Fengnan Chang <changfengnan@xxxxxxxx>

Don't create discard thread when device not support realtime discard.

Signed-off-by: Fengnan Chang <changfengnan@xxxxxxxx>
Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
---
 fs/f2fs/f2fs.h    |  1 +
 fs/f2fs/segment.c | 29 +++++++++++++++++++++--------
 fs/f2fs/super.c   | 34 ++++++++++++++++++++++++++++++++--
 3 files changed, 54 insertions(+), 10 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index d24fd5045712..60a408af53a3 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3483,6 +3483,7 @@ int f2fs_flush_device_cache(struct f2fs_sb_info *sbi);
 void f2fs_destroy_flush_cmd_control(struct f2fs_sb_info *sbi, bool free);
 void f2fs_invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr);
 bool f2fs_is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr);
+int f2fs_start_discard_thread(struct f2fs_sb_info *sbi);
 void f2fs_drop_discard_cmd(struct f2fs_sb_info *sbi);
 void f2fs_stop_discard_thread(struct f2fs_sb_info *sbi);
 bool f2fs_issue_discard_timeout(struct f2fs_sb_info *sbi);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index ca9876a6d396..b83a4a1e5023 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2112,7 +2112,27 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
 wakeup:
 	wake_up_discard_thread(sbi, false);
 }
+int f2fs_start_discard_thread(struct f2fs_sb_info *sbi)
+{
+	dev_t dev = sbi->sb->s_bdev->bd_dev;
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	int err = 0;
 
+	if (!dcc)
+		return -EINVAL;
+	if (!f2fs_realtime_discard_enable(sbi))
+		return 0;
+
+	dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
+				"f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
+	if (IS_ERR(dcc->f2fs_issue_discard)) {
+		err = PTR_ERR(dcc->f2fs_issue_discard);
+		kfree(dcc);
+		SM_I(sbi)->dcc_info = NULL;
+		return err;
+	}
+	return err;
+}
 static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
 {
 	dev_t dev = sbi->sb->s_bdev->bd_dev;
@@ -2153,14 +2173,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
 	init_waitqueue_head(&dcc->discard_wait_queue);
 	SM_I(sbi)->dcc_info = dcc;
 init_thread:
-	dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
-				"f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
-	if (IS_ERR(dcc->f2fs_issue_discard)) {
-		err = PTR_ERR(dcc->f2fs_issue_discard);
-		kfree(dcc);
-		SM_I(sbi)->dcc_info = NULL;
-		return err;
-	}
+	err = f2fs_start_discard_thread(sbi);
 
 	return err;
 }
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 84cd085020cd..ff19c30cd6a1 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2101,12 +2101,15 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 	bool need_restart_gc = false, need_stop_gc = false;
 	bool need_restart_ckpt = false, need_stop_ckpt = false;
 	bool need_restart_flush = false, need_stop_flush = false;
+	bool need_enable_ckpt = false, need_disable_ckpt = false;
 	bool no_extent_cache = !test_opt(sbi, EXTENT_CACHE);
 	bool enable_checkpoint = !test_opt(sbi, DISABLE_CHECKPOINT);
 	bool no_io_align = !F2FS_IO_ALIGNED(sbi);
 	bool no_atgc = !test_opt(sbi, ATGC);
+	bool no_discard = !test_opt(sbi, DISCARD);
 	bool no_compress_cache = !test_opt(sbi, COMPRESS_CACHE);
 	bool block_unit_discard = f2fs_block_unit_discard(sbi);
+	struct discard_cmd_control *dcc;
 #ifdef CONFIG_QUOTA
 	int i, j;
 #endif
@@ -2274,7 +2277,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 	} else {
 		err = f2fs_create_flush_cmd_control(sbi);
 		if (err)
-			goto restore_ckpt;
+			goto restore_ckpt_thread;
 		need_stop_flush = true;
 	}
 
@@ -2283,8 +2286,28 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 			err = f2fs_disable_checkpoint(sbi);
 			if (err)
 				goto restore_flush;
+			need_enable_ckpt = true;
 		} else {
 			f2fs_enable_checkpoint(sbi);
+			need_disable_ckpt = true;
+		}
+	}
+
+	if (no_discard == !!test_opt(sbi, DISCARD)) {
+		if (test_opt(sbi, DISCARD)) {
+			err = f2fs_start_discard_thread(sbi);
+			if (err)
+				goto restore_ckpt;
+
+		} else {
+			dcc = SM_I(sbi)->dcc_info;
+			if (!dcc) {
+				err = -EINVAL;
+				goto restore_ckpt;
+			}
+			f2fs_stop_discard_thread(sbi);
+			if (unlikely(atomic_read(&dcc->discard_cmd_cnt)))
+				f2fs_issue_discard_timeout(sbi);
 		}
 	}
 
@@ -2302,6 +2325,13 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 	adjust_unusable_cap_perc(sbi);
 	*flags = (*flags & ~SB_LAZYTIME) | (sb->s_flags & SB_LAZYTIME);
 	return 0;
+restore_ckpt:
+	if (need_enable_ckpt) {
+		f2fs_enable_checkpoint(sbi);
+	} else if (need_disable_ckpt) {
+		if (f2fs_disable_checkpoint(sbi))
+			f2fs_warn(sbi, "checkpoint has been enable");
+	}
 restore_flush:
 	if (need_restart_flush) {
 		if (f2fs_create_flush_cmd_control(sbi))
@@ -2310,7 +2340,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
 		clear_opt(sbi, FLUSH_MERGE);
 		f2fs_destroy_flush_cmd_control(sbi, false);
 	}
-restore_ckpt:
+restore_ckpt_thread:
 	if (need_restart_ckpt) {
 		if (f2fs_start_ckpt_thread(sbi))
 			f2fs_warn(sbi, "background ckpt thread has stopped");
-- 
2.32.0