[PATCH v4] f2fs: avoid to select pinned section during checkpoint=disable

[Chao Yu]

From: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>

The f2fs_gc uses a bitmap to indicate pinned sections, but when disabling
chckpoint, we call f2fs_gc() with NULL_SEGNO which selects the same dirty
segment as a victim all the time, resulting in checkpoint=disable failure.
Let's pick another one, if we fail to collect it.

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
v4:
- use sec_freed instead of total_freed
 fs/f2fs/f2fs.h    |  2 +-
 fs/f2fs/file.c    |  8 ++++----
 fs/f2fs/gc.c      | 17 +++++++++++------
 fs/f2fs/segment.c |  2 +-
 fs/f2fs/super.c   |  2 +-
 5 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 56adc3b68e14..0f8c426aed50 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3787,7 +3787,7 @@ int f2fs_start_gc_thread(struct f2fs_sb_info *sbi);
 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi);
 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode);
 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, bool background, bool force,
-			unsigned int segno);
+			unsigned int segno, unsigned int nr_section);
 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi);
 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count);
 int __init f2fs_create_garbage_collection_cache(void);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index e4cf8b7b23aa..07d2fa6c774b 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1684,7 +1684,7 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
 		if (has_not_enough_free_secs(sbi, 0,
 			GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
 			f2fs_down_write(&sbi->gc_lock);
-			err = f2fs_gc(sbi, true, false, false, NULL_SEGNO);
+			err = f2fs_gc(sbi, true, false, false, NULL_SEGNO, 0);
 			if (err && err != -ENODATA && err != -EAGAIN)
 				goto out_err;
 		}
@@ -2472,7 +2472,7 @@ static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
 		f2fs_down_write(&sbi->gc_lock);
 	}
 
-	ret = f2fs_gc(sbi, sync, true, false, NULL_SEGNO);
+	ret = f2fs_gc(sbi, sync, true, false, NULL_SEGNO, 0);
 out:
 	mnt_drop_write_file(filp);
 	return ret;
@@ -2509,7 +2509,7 @@ static int __f2fs_ioc_gc_range(struct file *filp, struct f2fs_gc_range *range)
 	}
 
 	ret = f2fs_gc(sbi, range->sync, true, false,
-				GET_SEGNO(sbi, range->start));
+				GET_SEGNO(sbi, range->start), 0);
 	if (ret) {
 		if (ret == -EBUSY)
 			ret = -EAGAIN;
@@ -2966,7 +2966,7 @@ static int f2fs_ioc_flush_device(struct file *filp, unsigned long arg)
 		sm->last_victim[GC_CB] = end_segno + 1;
 		sm->last_victim[GC_GREEDY] = end_segno + 1;
 		sm->last_victim[ALLOC_NEXT] = end_segno + 1;
-		ret = f2fs_gc(sbi, true, true, true, start_segno);
+		ret = f2fs_gc(sbi, true, true, true, start_segno, 0);
 		if (ret == -EAGAIN)
 			ret = 0;
 		else if (ret < 0)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 3009c0a97ab4..d13a86272e8b 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -142,7 +142,7 @@ static int gc_thread_func(void *data)
 			sync_mode = false;
 
 		/* if return value is not zero, no victim was selected */
-		if (f2fs_gc(sbi, sync_mode, !foreground, false, NULL_SEGNO))
+		if (f2fs_gc(sbi, sync_mode, !foreground, false, NULL_SEGNO, 0))
 			wait_ms = gc_th->no_gc_sleep_time;
 
 		if (foreground)
@@ -1754,7 +1754,8 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 }
 
 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
-			bool background, bool force, unsigned int segno)
+			bool background, bool force, unsigned int segno,
+			unsigned int nr_section)
 {
 	int gc_type = sync ? FG_GC : BG_GC;
 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
@@ -1841,11 +1842,15 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 	if (gc_type == FG_GC)
 		sbi->cur_victim_sec = NULL_SEGNO;
 
-	if (sync)
-		goto stop;
-
-	if (!has_not_enough_free_secs(sbi, sec_freed, 0))
+	if (sync || !has_not_enough_free_secs(sbi, sec_freed, 0)) {
+		/*
+		 * f2fs_disable_checkpoint() needs to migrate enough section
+		 * before f2fs_gc() exits.
+		 */
+		if (sec_freed < nr_section)
+			goto gc_more;
 		goto stop;
+	}
 
 	if (skipped_round <= MAX_SKIP_GC_COUNT || skipped_round * 2 < round) {
 
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 8c17fed8987e..3a3e2cec2ac4 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -524,7 +524,7 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
 			finish_wait(&sbi->gc_thread->fggc_wq, &wait);
 		} else {
 			f2fs_down_write(&sbi->gc_lock);
-			f2fs_gc(sbi, false, false, false, NULL_SEGNO);
+			f2fs_gc(sbi, false, false, false, NULL_SEGNO, 0);
 		}
 	}
 }
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index d06a577a1208..2f0ad9ffbf17 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2076,7 +2076,7 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
 
 	while (!f2fs_time_over(sbi, DISABLE_TIME)) {
 		f2fs_down_write(&sbi->gc_lock);
-		err = f2fs_gc(sbi, true, false, false, NULL_SEGNO);
+		err = f2fs_gc(sbi, true, false, false, NULL_SEGNO, 1);
 		if (err == -ENODATA) {
 			err = 0;
 			break;
-- 
2.32.0