Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 2 Feb 2022 16:34:25 -0800
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH v2] f2fs: add a way to limit roll forward recovery time
Message-ID: <YfsjEb2ii3eyPzng@google.com>
References: <20220127214102.2040254-1-jaegeuk@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220127214102.2040254-1-jaegeuk@kernel.org>
Precedence: bulk

This adds a sysfs entry to call checkpoint during fsync() in order to avoid
long elapsed time to run roll-forward recovery when booting the device.
Default value doesn't enforce the limitation which is same as before.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
v2 from v1:
 - make the default w/o enforcement

 Documentation/ABI/testing/sysfs-fs-f2fs | 6 ++++++
 fs/f2fs/checkpoint.c                    | 1 +
 fs/f2fs/f2fs.h                          | 3 +++
 fs/f2fs/node.c                          | 2 ++
 fs/f2fs/node.h                          | 3 +++
 fs/f2fs/recovery.c                      | 4 ++++
 fs/f2fs/sysfs.c                         | 2 ++
 7 files changed, 21 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 87d3884c90ea..ce8103f522cb 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -567,3 +567,9 @@ Contact:	"Daeho Jeong" <daehojeong@google.com>
 Description:	You can set the trial count limit for GC urgent high mode with this value.
 		If GC thread gets to the limit, the mode will turn back to GC normal mode.
 		By default, the value is zero, which means there is no limit like before.
+
+What:		/sys/fs/f2fs/<disk>/max_roll_forward_node_blocks
+Date:		January 2022
+Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
+Description:	Controls max # of node block writes to be used for roll forward
+		recovery. This can limit the roll forward recovery time.
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index deeda95688f0..57a2d9164bee 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1543,6 +1543,7 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 	/* update user_block_counts */
 	sbi->last_valid_block_count = sbi->total_valid_block_count;
 	percpu_counter_set(&sbi->alloc_valid_block_count, 0);
+	percpu_counter_set(&sbi->rf_node_block_count, 0);
 
 	/* Here, we have one bio having CP pack except cp pack 2 page */
 	f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 63c90416364b..6ddb98ff0b7c 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -913,6 +913,7 @@ struct f2fs_nm_info {
 	nid_t max_nid;			/* maximum possible node ids */
 	nid_t available_nids;		/* # of available node ids */
 	nid_t next_scan_nid;		/* the next nid to be scanned */
+	nid_t max_rf_node_blocks;	/* max # of nodes for recovery */
 	unsigned int ram_thresh;	/* control the memory footprint */
 	unsigned int ra_nid_pages;	/* # of nid pages to be readaheaded */
 	unsigned int dirty_nats_ratio;	/* control dirty nats ratio threshold */
@@ -1684,6 +1685,8 @@ struct f2fs_sb_info {
 	atomic_t nr_pages[NR_COUNT_TYPE];
 	/* # of allocated blocks */
 	struct percpu_counter alloc_valid_block_count;
+	/* # of node block writes as roll forward recovery */
+	struct percpu_counter rf_node_block_count;
 
 	/* writeback control */
 	atomic_t wb_sync_req[META];	/* count # of WB_SYNC threads */
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 93512f8859d5..0d9883457579 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1782,6 +1782,7 @@ int f2fs_fsync_node_pages(struct f2fs_sb_info *sbi, struct inode *inode,
 
 			if (!atomic || page == last_page) {
 				set_fsync_mark(page, 1);
+				percpu_counter_inc(&sbi->rf_node_block_count);
 				if (IS_INODE(page)) {
 					if (is_inode_flag_set(inode,
 								FI_DIRTY_INODE))
@@ -3218,6 +3219,7 @@ static int init_node_manager(struct f2fs_sb_info *sbi)
 	nm_i->ram_thresh = DEF_RAM_THRESHOLD;
 	nm_i->ra_nid_pages = DEF_RA_NID_PAGES;
 	nm_i->dirty_nats_ratio = DEF_DIRTY_NAT_RATIO_THRESHOLD;
+	nm_i->max_rf_node_blocks = DEF_RF_NODE_BLOCKS;
 
 	INIT_RADIX_TREE(&nm_i->free_nid_root, GFP_ATOMIC);
 	INIT_LIST_HEAD(&nm_i->free_nid_list);
diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
index 18b98cf0465b..4c1d34bfea78 100644
--- a/fs/f2fs/node.h
+++ b/fs/f2fs/node.h
@@ -31,6 +31,9 @@
 /* control total # of nats */
 #define DEF_NAT_CACHE_THRESHOLD			100000
 
+/* control total # of node writes used for roll-fowrad recovery */
+#define DEF_RF_NODE_BLOCKS			0
+
 /* vector size for gang look-up from nat cache that consists of radix tree */
 #define NATVEC_SIZE	64
 #define SETVEC_SIZE	32
diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index 10d152cfa58d..1c8041fd854e 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -53,9 +53,13 @@ extern struct kmem_cache *f2fs_cf_name_slab;
 bool f2fs_space_for_roll_forward(struct f2fs_sb_info *sbi)
 {
 	s64 nalloc = percpu_counter_sum_positive(&sbi->alloc_valid_block_count);
+	u32 rf_node = percpu_counter_sum_positive(&sbi->rf_node_block_count);
 
 	if (sbi->last_valid_block_count + nalloc > sbi->user_block_count)
 		return false;
+	if (NM_I(sbi)->max_rf_node_blocks &&
+			rf_node >= NM_I(sbi)->max_rf_node_blocks)
+		return false;
 	return true;
 }
 
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 281bc0133ee6..47efcf233afd 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -732,6 +732,7 @@ F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ssr_sections, min_ssr_sections);
 F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, ram_thresh, ram_thresh);
 F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, ra_nid_pages, ra_nid_pages);
 F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, dirty_nats_ratio, dirty_nats_ratio);
+F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, max_roll_forward_node_blocks, max_rf_node_blocks);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, max_victim_search, max_victim_search);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, migration_granularity, migration_granularity);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, dir_level, dir_level);
@@ -855,6 +856,7 @@ static struct attribute *f2fs_attrs[] = {
 	ATTR_LIST(ram_thresh),
 	ATTR_LIST(ra_nid_pages),
 	ATTR_LIST(dirty_nats_ratio),
+	ATTR_LIST(max_roll_forward_node_blocks),
 	ATTR_LIST(cp_interval),
 	ATTR_LIST(idle_interval),
 	ATTR_LIST(discard_idle_interval),
-- 
2.35.0.rc2.247.g8bbb082509-goog