From da4ff602f405703aeae35acdd776d71cc535b6f5 Mon Sep 17 00:00:00 2001
From: Vivek Haldar <haldar@google.com>
Date: Sun, 22 May 2011 21:24:16 -0400
Subject: [PATCH] --- yaml --- r: 251741 b: refs/heads/master c:
 77f4135f2a219a2127be6cc1208c42e6175b11dd h: refs/heads/master i:   251739:
 f3bf1b9bb8bbe742887455f9e1d39c3fb5288acd v: v3

---
 [refs]                  |  2 +-
 trunk/fs/ext4/ext4.h    |  3 +++
 trunk/fs/ext4/extents.c |  7 ++++++-
 trunk/fs/ext4/super.c   | 16 ++++++++++++++++
 4 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 177175759c82..6242782d1a63 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 93917411be8db5d21abf15c781dfa43c5cc6edf2
+refs/heads/master: 77f4135f2a219a2127be6cc1208c42e6175b11dd
diff --git a/trunk/fs/ext4/ext4.h b/trunk/fs/ext4/ext4.h
index 6ce3c7c8574c..65fe1dc0c750 100644
--- a/trunk/fs/ext4/ext4.h
+++ b/trunk/fs/ext4/ext4.h
@@ -1144,6 +1144,9 @@ struct ext4_sb_info {
 	unsigned long s_ext_blocks;
 	unsigned long s_ext_extents;
 #endif
+	/* ext4 extent cache stats */
+	unsigned long extent_cache_hits;
+	unsigned long extent_cache_misses;
 
 	/* for buddy allocator */
 	struct ext4_group_info ***s_group_info;
diff --git a/trunk/fs/ext4/extents.c b/trunk/fs/ext4/extents.c
index 9a3844adb1cb..4444317d141a 100644
--- a/trunk/fs/ext4/extents.c
+++ b/trunk/fs/ext4/extents.c
@@ -2035,6 +2035,7 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
 			struct ext4_extent *ex)
 {
 	struct ext4_ext_cache *cex;
+	struct ext4_sb_info *sbi;
 	int ret = 0;
 
 	/*
@@ -2042,6 +2043,7 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
 	 */
 	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
 	cex = &EXT4_I(inode)->i_cached_extent;
+	sbi = EXT4_SB(inode->i_sb);
 
 	/* has cache valid data? */
 	if (cex->ec_len == 0)
@@ -2057,6 +2059,10 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
 		ret = 1;
 	}
 errout:
+	if (!ret)
+		sbi->extent_cache_misses++;
+	else
+		sbi->extent_cache_hits++;
 	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 	return ret;
 }
@@ -3901,4 +3907,3 @@ int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 
 	return error;
 }
-
diff --git a/trunk/fs/ext4/super.c b/trunk/fs/ext4/super.c
index fdce4eebce0c..874dd25b7481 100644
--- a/trunk/fs/ext4/super.c
+++ b/trunk/fs/ext4/super.c
@@ -2439,6 +2439,18 @@ static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
 			  EXT4_SB(sb)->s_sectors_written_start) >> 1)));
 }
 
+static ssize_t extent_cache_hits_show(struct ext4_attr *a,
+				      struct ext4_sb_info *sbi, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_hits);
+}
+
+static ssize_t extent_cache_misses_show(struct ext4_attr *a,
+					struct ext4_sb_info *sbi, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_misses);
+}
+
 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
 					  struct ext4_sb_info *sbi,
 					  const char *buf, size_t count)
@@ -2496,6 +2508,8 @@ static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
 EXT4_RO_ATTR(delayed_allocation_blocks);
 EXT4_RO_ATTR(session_write_kbytes);
 EXT4_RO_ATTR(lifetime_write_kbytes);
+EXT4_RO_ATTR(extent_cache_hits);
+EXT4_RO_ATTR(extent_cache_misses);
 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
 		 inode_readahead_blks_store, s_inode_readahead_blks);
 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
@@ -2511,6 +2525,8 @@ static struct attribute *ext4_attrs[] = {
 	ATTR_LIST(delayed_allocation_blocks),
 	ATTR_LIST(session_write_kbytes),
 	ATTR_LIST(lifetime_write_kbytes),
+	ATTR_LIST(extent_cache_hits),
+	ATTR_LIST(extent_cache_misses),
 	ATTR_LIST(inode_readahead_blks),
 	ATTR_LIST(inode_goal),
 	ATTR_LIST(mb_stats),