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From:   Hyeongseok Kim <hyeongseok@gmail.com>
To:     namjae.jeon@samsung.com, sj1557.seo@samsung.com
Cc:     linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Hyeongseok Kim <hyeongseok@gmail.com>
Subject: [PATCH] exfat: improve write performance when dirsync enabled
Date:   Mon, 15 Mar 2021 13:12:55 +0900
Message-Id: <20210315041255.174167-1-hyeongseok@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Degradation of write speed caused by frequent disk access for cluster
bitmap update on every cluster allocation could be improved by
selective syncing bitmap buffer. Change to flush bitmap buffer only
for the directory related operations.

Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>
---
 fs/exfat/balloc.c   | 4 ++--
 fs/exfat/dir.c      | 2 +-
 fs/exfat/exfat_fs.h | 4 ++--
 fs/exfat/fatent.c   | 4 ++--
 fs/exfat/inode.c    | 3 ++-
 fs/exfat/namei.c    | 2 +-
 6 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c
index 78bc87d5a11b..cc5cffc4a769 100644
--- a/fs/exfat/balloc.c
+++ b/fs/exfat/balloc.c
@@ -141,7 +141,7 @@ void exfat_free_bitmap(struct exfat_sb_info *sbi)
 	kfree(sbi->vol_amap);
 }
 
-int exfat_set_bitmap(struct inode *inode, unsigned int clu)
+int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync)
 {
 	int i, b;
 	unsigned int ent_idx;
@@ -154,7 +154,7 @@ int exfat_set_bitmap(struct inode *inode, unsigned int clu)
 	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
 
 	set_bit_le(b, sbi->vol_amap[i]->b_data);
-	exfat_update_bh(sbi->vol_amap[i], IS_DIRSYNC(inode));
+	exfat_update_bh(sbi->vol_amap[i], sync);
 	return 0;
 }
 
diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index e1d5536de948..7efb1c6d4808 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -320,7 +320,7 @@ int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu)
 
 	exfat_chain_set(clu, EXFAT_EOF_CLUSTER, 0, ALLOC_NO_FAT_CHAIN);
 
-	ret = exfat_alloc_cluster(inode, 1, clu);
+	ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
 	if (ret)
 		return ret;
 
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index 169d0b602f5e..e77fe2f45cf2 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -389,7 +389,7 @@ int exfat_clear_volume_dirty(struct super_block *sb);
 #define exfat_get_next_cluster(sb, pclu) exfat_ent_get(sb, *(pclu), pclu)
 
 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
-		struct exfat_chain *p_chain);
+		struct exfat_chain *p_chain, bool sync_bmap);
 int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain);
 int exfat_ent_get(struct super_block *sb, unsigned int loc,
 		unsigned int *content);
@@ -408,7 +408,7 @@ int exfat_count_num_clusters(struct super_block *sb,
 /* balloc.c */
 int exfat_load_bitmap(struct super_block *sb);
 void exfat_free_bitmap(struct exfat_sb_info *sbi);
-int exfat_set_bitmap(struct inode *inode, unsigned int clu);
+int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync);
 void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync);
 unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu);
 int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count);
diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c
index fd6c7fd12762..e949e563443c 100644
--- a/fs/exfat/fatent.c
+++ b/fs/exfat/fatent.c
@@ -320,7 +320,7 @@ int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
 }
 
 int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
-		struct exfat_chain *p_chain)
+		struct exfat_chain *p_chain, bool sync_bmap)
 {
 	int ret = -ENOSPC;
 	unsigned int num_clusters = 0, total_cnt;
@@ -388,7 +388,7 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 		}
 
 		/* update allocation bitmap */
-		if (exfat_set_bitmap(inode, new_clu)) {
+		if (exfat_set_bitmap(inode, new_clu, sync_bmap)) {
 			ret = -EIO;
 			goto free_cluster;
 		}
diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c
index 730373e0965a..1803ef3220fd 100644
--- a/fs/exfat/inode.c
+++ b/fs/exfat/inode.c
@@ -179,7 +179,8 @@ static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
 			return -EIO;
 		}
 
-		ret = exfat_alloc_cluster(inode, num_to_be_allocated, &new_clu);
+		ret = exfat_alloc_cluster(inode, num_to_be_allocated, &new_clu,
+				inode_needs_sync(inode));
 		if (ret)
 			return ret;
 
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index d9e8ec689c55..1f7b3dc66fcd 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -340,7 +340,7 @@ static int exfat_find_empty_entry(struct inode *inode,
 		exfat_chain_set(&clu, last_clu + 1, 0, p_dir->flags);
 
 		/* allocate a cluster */
-		ret = exfat_alloc_cluster(inode, 1, &clu);
+		ret = exfat_alloc_cluster(inode, 1, &clu, IS_DIRSYNC(inode));
 		if (ret)
 			return ret;
 
-- 
2.27.0.83.g0313f36