linux-ext4 - [PATCH 3/5] ext4: optimize to reduce redundant ext4

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Date:   Tue, 29 May 2018 20:45:15 +0900
From:   Wang Shilong <wangshilong1991@...il.com>
To:     linux-ext4@...r.kernel.org
Cc:     andreas.dilger@...el.com, sihara@....com, wshilong@....com
Subject: [PATCH 3/5] ext4: optimize to reduce redundant ext4_error()

From: Wang Shilong <wshilong@....com>

only call ext4_error() if new corrupted bit set,
this could save us repeated error messages and
unecessary super block write.

Suggested-by: Andreas Dilger <adilger@...ger.ca>
Signed-off-by: Wang Shilong <wshilong@....com>
---
 fs/ext4/ext4.h  | 25 ++++++++++++++++---------
 fs/ext4/super.c | 14 ++++++++++----
 2 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ed5b988..26f8c12 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2530,9 +2530,9 @@ extern int ext4_alloc_flex_bg_array(struct super_block *sb,
 				    ext4_group_t ngroup);
 extern const char *ext4_decode_error(struct super_block *sb, int errno,
 				     char nbuf[16]);
-extern void __ext4_mark_group_bitmap_corrupted(struct super_block *sb,
-					       ext4_group_t block_group,
-					       unsigned int flags);
+extern int __ext4_mark_group_bitmap_corrupted(struct super_block *sb,
+					      ext4_group_t block_group,
+					      unsigned int flags);
 
 extern __printf(4, 5)
 void __ext4_error(struct super_block *, const char *, unsigned int,
@@ -2596,9 +2596,12 @@ void __ext4_grp_locked_error(const char *, unsigned int,
 				flags, fmt, ##__VA_ARGS__)
 #define ext4_mark_group_bitmap_corrupted(sb, group, flags, fmt, ...)	\
 	do {								\
-		__ext4_error(sb, __func__, __LINE__,			\
-			     fmt, ##__VA_ARGS__);			\
-		__ext4_mark_group_bitmap_corrupted(sb, group, flags);	\
+		int ret;						\
+		ret = __ext4_mark_group_bitmap_corrupted(sb, group,	\
+							flags);		\
+		if (ret)						\
+			__ext4_error(sb, __func__, __LINE__,		\
+				     fmt, ##__VA_ARGS__);		\
 	} while (0)
 
 
@@ -2648,9 +2651,13 @@ void __ext4_grp_locked_error(const char *, unsigned int,
 } while (0)
 #define ext4_mark_group_bitmap_corrupted(sb, group, flags, fmt, ...)	\
 	do {								\
-		no_printk(fmt, ##__VA_ARGS__);				\
-		__ext4_error(sb, "", 0, " ");				\
-		__ext4_mark_group_bitmap_corrupted(sb, group, flags);	\
+		int ret;						\
+		ret = __ext4_mark_group_bitmap_corrupted(sb, group,	\
+							 flags);	\
+		if (ret) {						\
+			no_printk(fmt, ##__VA_ARGS__);			\
+			__ext4_error(sb, "", 0, " ");			\
+		}							\
 	} while (0)
 
 #endif
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 554bceb..9f88991 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -766,21 +766,24 @@ void __ext4_grp_locked_error(const char *function, unsigned int line,
 	return;
 }
 
-void __ext4_mark_group_bitmap_corrupted(struct super_block *sb,
-					ext4_group_t group,
-					unsigned int flags)
+int __ext4_mark_group_bitmap_corrupted(struct super_block *sb,
+				       ext4_group_t group,
+				       unsigned int flags)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
 	struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
 	int ret;
+	int set = 0;
 
 	if (flags & EXT4_GROUP_INFO_BBITMAP_CORRUPT) {
 		ret = ext4_test_and_set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT,
 					    &grp->bb_state);
-		if (!ret)
+		if (!ret) {
 			percpu_counter_sub(&sbi->s_freeclusters_counter,
 					   grp->bb_free);
+			set = 1;
+		}
 	}
 
 	if (flags & EXT4_GROUP_INFO_IBITMAP_CORRUPT) {
@@ -792,8 +795,11 @@ void __ext4_mark_group_bitmap_corrupted(struct super_block *sb,
 			count = ext4_free_inodes_count(sb, gdp);
 			percpu_counter_sub(&sbi->s_freeinodes_counter,
 					   count);
+			set = 1;
 		}
 	}
+
+	return set;
 }
 
 void ext4_update_dynamic_rev(struct super_block *sb)
-- 
1.8.3.1