f2fs: do not stop GC when requiring a free section

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,
for example. Let's pick another one, if we fail to collect it.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

5 files changed, 22 insertions, 11 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9920b2d6af8f..492af5b96de1 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1271,6 +1271,7 @@ struct f2fs_gc_control {
 	bool no_bg_gc;			/* check the space and stop bg_gc */
 	bool should_migrate_blocks;	/* should migrate blocks */
 	bool err_gc_skipped;		/* return EAGAIN if GC skipped */
+	unsigned int nr_free_secs;	/* # of free sections to do GC */
 };
 
 /* For s_flag in struct f2fs_sb_info */
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index d0547bef0851..216081ea8c81 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1650,7 +1650,8 @@ static int expand_inode_data(struct inode *inode, loff_t offset,
 	struct f2fs_gc_control gc_control = { .victim_segno = NULL_SEGNO,
 			.init_gc_type = FG_GC,
 			.should_migrate_blocks = false,
-			.err_gc_skipped = true };
+			.err_gc_skipped = true,
+			.nr_free_secs = 0 };
 	pgoff_t pg_start, pg_end;
 	loff_t new_size = i_size_read(inode);
 	loff_t off_end;
@@ -2350,7 +2351,8 @@ static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct f2fs_gc_control gc_control = { .victim_segno = NULL_SEGNO,
 			.no_bg_gc = false,
-			.should_migrate_blocks = false };
+			.should_migrate_blocks = false,
+			.nr_free_secs = 0 };
 	__u32 sync;
 	int ret;
 
@@ -2391,7 +2393,8 @@ static int __f2fs_ioc_gc_range(struct file *filp, struct f2fs_gc_range *range)
 			.init_gc_type = range->sync ? FG_GC : BG_GC,
 			.no_bg_gc = false,
 			.should_migrate_blocks = false,
-			.err_gc_skipped = range->sync };
+			.err_gc_skipped = range->sync,
+			.nr_free_secs = 0 };
 	u64 end;
 	int ret;
 
@@ -2837,7 +2840,8 @@ static int f2fs_ioc_flush_device(struct file *filp, unsigned long arg)
 	struct f2fs_gc_control gc_control = {
 			.init_gc_type = FG_GC,
 			.should_migrate_blocks = true,
-			.err_gc_skipped = true };
+			.err_gc_skipped = true,
+			.nr_free_secs = 0 };
 	int ret;
 
 	if (!capable(CAP_SYS_ADMIN))
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index e275b72bc65f..d5fb426e0747 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -147,6 +147,7 @@ do_gc:
 
 		gc_control.init_gc_type = sync_mode ? FG_GC : BG_GC;
 		gc_control.no_bg_gc = foreground;
+		gc_control.nr_free_secs = foreground ? 1 : 0;
 
 		/* if return value is not zero, no victim was selected */
 		if (f2fs_gc(sbi, &gc_control))
@@ -1761,6 +1762,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
 	unsigned int skipped_round = 0, round = 0;
 
 	trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc,
+				gc_control->nr_free_secs,
 				get_pages(sbi, F2FS_DIRTY_NODES),
 				get_pages(sbi, F2FS_DIRTY_DENTS),
 				get_pages(sbi, F2FS_DIRTY_IMETA),
@@ -1823,12 +1825,13 @@ retry:
 	if (gc_type == FG_GC)
 		sbi->cur_victim_sec = NULL_SEGNO;
 
-	if (gc_control->init_gc_type == FG_GC)
-		goto stop;
-
-	if (!has_not_enough_free_secs(sbi,
-			(gc_type == FG_GC) ? sec_freed : 0, 0))
+	if (gc_control->init_gc_type == FG_GC ||
+	    !has_not_enough_free_secs(sbi,
+				(gc_type == FG_GC) ? sec_freed : 0, 0)) {
+		if (gc_type == FG_GC && sec_freed < gc_control->nr_free_secs)
+			goto go_gc_more;
 		goto stop;
+	}
 
 	/* FG_GC stops GC by skip_count */
 	if (gc_type == FG_GC) {
@@ -1849,6 +1852,7 @@ retry:
 		if (ret)
 			goto stop;
 	}
+go_gc_more:
 	segno = NULL_SEGNO;
 	goto gc_more;
 
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 8b4f2b1d2cca..0a4180f64291 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -404,7 +404,8 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need)
 				.init_gc_type = BG_GC,
 				.no_bg_gc = true,
 				.should_migrate_blocks = false,
-				.err_gc_skipped = false };
+				.err_gc_skipped = false,
+				.nr_free_secs = 1 };
 			f2fs_down_write(&sbi->gc_lock);
 			f2fs_gc(sbi, &gc_control);
 		}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index a28c27eed6d0..63daae67a9d9 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2080,7 +2080,8 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
 			.victim_segno = NULL_SEGNO,
 			.init_gc_type = FG_GC,
 			.should_migrate_blocks = false,
-			.err_gc_skipped = true };
+			.err_gc_skipped = true,
+			.nr_free_secs = 1 };
 
 		f2fs_down_write(&sbi->gc_lock);
 		err = f2fs_gc(sbi, &gc_control);