[PATCH 3/3] btrfs: consolidate auto defrag kick off policies

[Anand Jain <anand.jain@oracle.com>]

As of now writes smaller than 64k for non compressed extents and 16k
for compressed extents inside eof are considered as candidate
for auto defrag, put them together at a place.
---
 fs/btrfs/inode.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 79f073e94f2d..b157575166c6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -388,6 +388,22 @@ static inline int inode_need_compress(struct inode *inode)
 	return 0;
 }
 
+static inline void inode_should_defrag(struct inode *inode,
+		u64 start, u64 end, u64 num_bytes, int comp_type)
+{
+	u64 small_write = SZ_64K;
+	if (comp_type)
+		small_write = SZ_16K;
+
+	if (!num_bytes)
+		num_bytes = end - start + 1;
+
+	/* If this is a small write inside eof, kick off a defrag */
+	if (num_bytes < small_write &&
+	    (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
+		btrfs_add_inode_defrag(NULL, inode);
+}
+
 /*
  * we create compressed extents in two phases.  The first
  * phase compresses a range of pages that have already been
@@ -429,10 +445,7 @@ static noinline void compress_file_range(struct inode *inode,
 	int compress_type = root->fs_info->compress_type;
 	int redirty = 0;
 
-	/* if this is a small write inside eof, kick off a defrag */
-	if ((end - start + 1) < SZ_16K &&
-	    (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
-		btrfs_add_inode_defrag(NULL, inode);
+	inode_should_defrag(inode, start, end, 0, compress_type);
 
 	actual_end = min_t(u64, isize, end + 1);
 again:
@@ -960,10 +973,8 @@ static noinline int cow_file_range(struct inode *inode,
 	num_bytes = ALIGN(end - start + 1, blocksize);
 	num_bytes = max(blocksize,  num_bytes);
 
-	/* if this is a small write inside eof, kick off defrag */
-	if (num_bytes < SZ_64K &&
-	    (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
-		btrfs_add_inode_defrag(NULL, inode);
+	inode_should_defrag(inode, start, end, num_bytes,
+						BTRFS_COMPRESS_NONE);
 
 	if (start == 0) {
 		/* lets try to make an inline extent */
-- 
2.10.0