[PATCH] f2fs: fix to enable readahead last NAT block

[PATCH] f2fs: fix to enable readahead last NAT block

[Chao Yu]

We skip reading last one of NAT blocks when readahead them since max value of
valid block is calculated incorrectly. We should fix this problem to avoid it.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
---
 fs/f2fs/checkpoint.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 744c68b..75189b1 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -77,7 +77,7 @@ inline int get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
 {
 	switch (type) {
 	case META_NAT:
-		return NM_I(sbi)->max_nid / NAT_ENTRY_PER_BLOCK;
+		return (NM_I(sbi)->max_nid + 3) / NAT_ENTRY_PER_BLOCK;
 	case META_SIT:
 		return SIT_BLK_CNT(sbi);
 	case META_SSA:
-- 
1.7.9.5



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Re: [f2fs-dev] [PATCH] f2fs: fix to enable readahead last NAT block

[Jaegeuk Kim]

Hi Chao,

How about this?

---
 fs/f2fs/f2fs.h | 1 +
 fs/f2fs/node.c | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 55152de..556d06b 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -244,6 +244,7 @@ static inline void set_raw_extent(struct extent_info
*ext,
 struct f2fs_nm_info {
 	block_t nat_blkaddr;		/* base disk address of NAT */
 	nid_t max_nid;			/* maximum possible node ids */
+	nid_t available_nids;		/* maximum available node ids */
 	nid_t next_scan_nid;		/* the next nid to be scanned */
 	unsigned int ram_thresh;	/* control the memory footprint */
 
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 837f5fd..5fb484c 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1447,7 +1447,7 @@ bool alloc_nid(struct f2fs_sb_info *sbi, nid_t
*nid)
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 	struct free_nid *i = NULL;
 retry:
-	if (unlikely(sbi->total_valid_node_count + 1 >= nm_i->max_nid))
+	if (unlikely(sbi->total_valid_node_count + 1 >= nm_i->available_nids))
 		return false;
 
 	spin_lock(&nm_i->free_nid_list_lock);
@@ -1859,8 +1859,10 @@ static int init_node_manager(struct f2fs_sb_info
*sbi)
 	nat_segs = le32_to_cpu(sb_raw->segment_count_nat) >> 1;
 	nat_blocks = nat_segs << le32_to_cpu(sb_raw->log_blocks_per_seg);
 
+	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks;
+
 	/* not used nids: 0, node, meta, (and root counted as valid node) */
-	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks - 3;
+	nm_i->available_nids = nm_i->max_nid - 3;
 	nm_i->fcnt = 0;
 	nm_i->nat_cnt = 0;
 	nm_i->ram_thresh = DEF_RAM_THRESHOLD;
-- 
1.8.4.474.g128a96c


-- 
Jaegeuk Kim
Samsung

RE: [f2fs-dev] [PATCH] f2fs: fix to enable readahead last NAT block

[Chao Yu]

Hi,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk.kim@samsung.com]
> Sent: Friday, April 18, 2014 10:16 AM
> To: Chao Yu
> Cc: linux-f2fs-devel@lists.sourceforge.net; linux-fsdevel@vger.kernel.org;
> linux-kernel@vger.kernel.org
> Subject: Re: [f2fs-dev] [PATCH] f2fs: fix to enable readahead last NAT block
> 
> Hi Chao,
> 
> How about this?

This modification can really fix the previously deadloop problem without bringing
more problem. I'd like use your patch.
Thanks.

One comment as following.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>

> 
> ---
>  fs/f2fs/f2fs.h | 1 +
>  fs/f2fs/node.c | 6 ++++--
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 55152de..556d06b 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -244,6 +244,7 @@ static inline void set_raw_extent(struct extent_info
> *ext,
>  struct f2fs_nm_info {
>  	block_t nat_blkaddr;		/* base disk address of NAT */
>  	nid_t max_nid;			/* maximum possible node ids */
> +	nid_t available_nids;		/* maximum available node ids */
>  	nid_t next_scan_nid;		/* the next nid to be scanned */
>  	unsigned int ram_thresh;	/* control the memory footprint */
> 
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 837f5fd..5fb484c 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1447,7 +1447,7 @@ bool alloc_nid(struct f2fs_sb_info *sbi, nid_t
> *nid)
>  	struct f2fs_nm_info *nm_i = NM_I(sbi);
>  	struct free_nid *i = NULL;
>  retry:
> -	if (unlikely(sbi->total_valid_node_count + 1 >= nm_i->max_nid))
> +	if (unlikely(sbi->total_valid_node_count + 1 >= nm_i->available_nids))

Could we use the last valid nid and modify like this?

	if (unlikely(sbi->total_valid_node_count + 1 > nm_i->available_nids))

>  		return false;
> 
>  	spin_lock(&nm_i->free_nid_list_lock);
> @@ -1859,8 +1859,10 @@ static int init_node_manager(struct f2fs_sb_info
> *sbi)
>  	nat_segs = le32_to_cpu(sb_raw->segment_count_nat) >> 1;
>  	nat_blocks = nat_segs << le32_to_cpu(sb_raw->log_blocks_per_seg);
> 
> +	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks;
> +
>  	/* not used nids: 0, node, meta, (and root counted as valid node) */
> -	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks - 3;
> +	nm_i->available_nids = nm_i->max_nid - 3;
>  	nm_i->fcnt = 0;
>  	nm_i->nat_cnt = 0;
>  	nm_i->ram_thresh = DEF_RAM_THRESHOLD;
> --
> 1.8.4.474.g128a96c
> 
> 
> --
> Jaegeuk Kim
> Samsung

Re: [PATCH] f2fs: fix to enable readahead last NAT block

[Jaegeuk Kim]

Got it.
The patch is like this.
Thanks,

>From 5f7a3bcf0df10bbb47a6e4409cc92ba8e6090674 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Date: Fri, 18 Apr 2014 11:14:37 +0900
Subject: [PATCH] f2fs: add available_nids to fix handling max_nid
correctly

This patch introduces available_nids for alloc_nids() and fixes max_nid
for
build_free_nids() and scan_nat_pages().

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
---
 fs/f2fs/f2fs.h | 1 +
 fs/f2fs/node.c | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 55152de..556d06b 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -244,6 +244,7 @@ static inline void set_raw_extent(struct extent_info
*ext,
 struct f2fs_nm_info {
 	block_t nat_blkaddr;		/* base disk address of NAT */
 	nid_t max_nid;			/* maximum possible node ids */
+	nid_t available_nids;		/* maximum available node ids */
 	nid_t next_scan_nid;		/* the next nid to be scanned */
 	unsigned int ram_thresh;	/* control the memory footprint */
 
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 837f5fd..6ebdba1 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1447,7 +1447,7 @@ bool alloc_nid(struct f2fs_sb_info *sbi, nid_t
*nid)
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 	struct free_nid *i = NULL;
 retry:
-	if (unlikely(sbi->total_valid_node_count + 1 >= nm_i->max_nid))
+	if (unlikely(sbi->total_valid_node_count + 1 > nm_i->available_nids))
 		return false;
 
 	spin_lock(&nm_i->free_nid_list_lock);
@@ -1859,8 +1859,10 @@ static int init_node_manager(struct f2fs_sb_info
*sbi)
 	nat_segs = le32_to_cpu(sb_raw->segment_count_nat) >> 1;
 	nat_blocks = nat_segs << le32_to_cpu(sb_raw->log_blocks_per_seg);
 
+	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks;
+
 	/* not used nids: 0, node, meta, (and root counted as valid node) */
-	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks - 3;
+	nm_i->available_nids = nm_i->max_nid - 3;
 	nm_i->fcnt = 0;
 	nm_i->nat_cnt = 0;
 	nm_i->ram_thresh = DEF_RAM_THRESHOLD;
-- 
1.8.4.474.g128a96c




-- 
Jaegeuk Kim
Samsung


------------------------------------------------------------------------------
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"Graph Databases" is the definitive new guide to graph databases and their
applications. Written by three acclaimed leaders in the field,
this first edition is now available. Download your free book today!
http://p.sf.net/sfu/NeoTech