[PATCH 4/5] f2fs: do not stop GC when requiring a free section

From: Jaegeuk Kim
Date: Fri May 06 2022 - 19:20:58 EST


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.

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
fs/f2fs/f2fs.h | 1 +
fs/f2fs/file.c | 12 ++++++++----
fs/f2fs/gc.c | 11 +++++++----
fs/f2fs/segment.c | 3 ++-
fs/f2fs/super.c | 3 ++-
include/trace/events/f2fs.h | 11 ++++++++---
6 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index d49b9b476592..27871f6efb01 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1282,6 +1282,7 @@ 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 0e7d101c3e65..7072c2b86b2f 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;
@@ -2453,7 +2454,8 @@ 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;

@@ -2494,7 +2496,8 @@ 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;

@@ -2940,7 +2943,8 @@ 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 ec3f6f876e76..f63576ff1c2d 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -147,6 +147,7 @@ static int gc_thread_func(void *data)

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))
@@ -1776,6 +1777,7 @@ 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),
@@ -1848,11 +1850,12 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
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, sec_freed, 0))
+ if ((gc_control->init_gc_type == FG_GC ||
+ !has_not_enough_free_secs(sbi, sec_freed, 0))) {
+ if (sec_freed < gc_control->nr_free_secs)
+ 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 bc63f0572c64..d6b9231ab0e1 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -528,7 +528,8 @@ 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 8b23fa6fc6b7..5d5b35067c3d 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2084,7 +2084,8 @@ 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);
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index 6699174977a3..349679a72301 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -653,18 +653,21 @@ TRACE_EVENT(f2fs_background_gc,
TRACE_EVENT(f2fs_gc_begin,

TP_PROTO(struct super_block *sb, int gc_type, bool no_bg_gc,
+ unsigned int nr_free_secs,
long long dirty_nodes, long long dirty_dents,
long long dirty_imeta, unsigned int free_sec,
unsigned int free_seg, int reserved_seg,
unsigned int prefree_seg),

- TP_ARGS(sb, gc_type, no_bg_gc, dirty_nodes, dirty_dents, dirty_imeta,
+ TP_ARGS(sb, gc_type, no_bg_gc, nr_free_secs, dirty_nodes,
+ dirty_dents, dirty_imeta,
free_sec, free_seg, reserved_seg, prefree_seg),

TP_STRUCT__entry(
__field(dev_t, dev)
__field(int, gc_type)
__field(bool, no_bg_gc)
+ __field(unsigned int, nr_free_secs)
__field(long long, dirty_nodes)
__field(long long, dirty_dents)
__field(long long, dirty_imeta)
@@ -678,6 +681,7 @@ TRACE_EVENT(f2fs_gc_begin,
__entry->dev = sb->s_dev;
__entry->gc_type = gc_type;
__entry->no_bg_gc = no_bg_gc;
+ __entry->nr_free_secs = nr_free_secs;
__entry->dirty_nodes = dirty_nodes;
__entry->dirty_dents = dirty_dents;
__entry->dirty_imeta = dirty_imeta;
@@ -687,12 +691,13 @@ TRACE_EVENT(f2fs_gc_begin,
__entry->prefree_seg = prefree_seg;
),

- TP_printk("dev = (%d,%d), gc_type = %s, no_background_GC = %d, nodes = %lld, "
- "dents = %lld, imeta = %lld, free_sec:%u, free_seg:%u, "
+ TP_printk("dev = (%d,%d), gc_type = %s, no_background_GC = %d, nr_free_secs = %u, "
+ "nodes = %lld, dents = %lld, imeta = %lld, free_sec:%u, free_seg:%u, "
"rsv_seg:%d, prefree_seg:%u",
show_dev(__entry->dev),
show_gc_type(__entry->gc_type),
__entry->no_bg_gc,
+ __entry->nr_free_secs,
__entry->dirty_nodes,
__entry->dirty_dents,
__entry->dirty_imeta,
--
2.36.0.512.ge40c2bad7a-goog