[PATCH] f2fs: enable atgc if atgc_age_threshold from user is less than elapsed_time

[Zhiguo Niu]

Now atgc can be enabled based on the following conditions:
-ATGC mount option is set
-elapsed_time is more than atgc_age_threshold already
but these conditions are check when umounted->mounted device again.
If the device has not be umounted->mounted for a long time, atgc can
not work even the above conditions met.

It is better to enable atgc dynamiclly when user change atgc_age_threshold
meanwhile this vale is less than elapsed_time and ATGC mount option is on.

Signed-off-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
---
 fs/f2fs/f2fs.h    |  1 +
 fs/f2fs/segment.c |  9 ++++-----
 fs/f2fs/sysfs.c   | 16 ++++++++++++++++
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 1974b6a..e441d2d 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3694,6 +3694,7 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
 int f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi);
 void f2fs_save_inmem_curseg(struct f2fs_sb_info *sbi);
 void f2fs_restore_inmem_curseg(struct f2fs_sb_info *sbi);
+int f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi);
 int f2fs_allocate_segment_for_resize(struct f2fs_sb_info *sbi, int type,
 					unsigned int start, unsigned int end);
 int f2fs_allocate_new_section(struct f2fs_sb_info *sbi, int type, bool force);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 71dc8042..44923d4 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2931,14 +2931,11 @@ static int get_atssr_segment(struct f2fs_sb_info *sbi, int type,
 	return ret;
 }
 
-static int __f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi)
+int f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi)
 {
 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_ALL_DATA_ATGC);
 	int ret = 0;
 
-	if (!sbi->am.atgc_enabled)
-		return 0;
-
 	f2fs_down_read(&SM_I(sbi)->curseg_lock);
 
 	mutex_lock(&curseg->curseg_mutex);
@@ -2955,7 +2952,9 @@ static int __f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi)
 }
 int f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi)
 {
-	return __f2fs_init_atgc_curseg(sbi);
+	if (!sbi->am.atgc_enabled)
+		return 0;
+	return f2fs_init_atgc_curseg(sbi);
 }
 
 static void __f2fs_save_inmem_curseg(struct f2fs_sb_info *sbi, int type)
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 09d3ecf..72676c5 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -673,6 +673,22 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
 		return count;
 	}
 
+	if (!strcmp(a->attr.name, "atgc_age_threshold")) {
+		if (t < 0)
+			return -EINVAL;
+		sbi->am.age_threshold = t;
+		if (sbi->am.atgc_enabled)
+			return count;
+
+		if (test_opt(sbi, ATGC) &&
+			le64_to_cpu(sbi->ckpt->elapsed_time) >= t) {
+			if (f2fs_init_atgc_curseg(sbi))
+				return -EINVAL;
+			sbi->am.atgc_enabled = true;
+		}
+		return count;
+	}
+
 	if (!strcmp(a->attr.name, "gc_segment_mode")) {
 		if (t < MAX_GC_MODE)
 			sbi->gc_segment_mode = t;
-- 
1.9.1