---

yaml
---
r: 95029
b: refs/heads/master
c: 3977c96
h: refs/heads/master
i:
  95027: f7a7cea
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 093a088b76352e0a6fdca84eb78b3aa65fbe6dd1
+refs/heads/master: 3977c965ec35ce1a7eac988ad313f0fc9aee9660

trunk/fs/ext4/extents.c

@@ -2212,6 +2212,8 @@ static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
 	return ret;
 }
 
+#define EXT4_EXT_ZERO_LEN 7
+
 /*
  * This function is called by ext4_ext_get_blocks() if someone tries to write
  * to an uninitialized extent. It may result in splitting the uninitialized
@@ -2254,6 +2256,18 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 	err = ext4_ext_get_access(handle, inode, path + depth);
 	if (err)
 		goto out;
+	/* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
+	if (ee_len <= 2*EXT4_EXT_ZERO_LEN) {
+		err =  ext4_ext_zeroout(inode, &orig_ex);
+		if (err)
+			goto fix_extent_len;
+		/* update the extent length and mark as initialized */
+		ex->ee_block = orig_ex.ee_block;
+		ex->ee_len   = orig_ex.ee_len;
+		ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
+		ext4_ext_dirty(handle, inode, path + depth);
+		return le16_to_cpu(ex->ee_len);
+	}
 
 	/* ex1: ee_block to iblock - 1 : uninitialized */
 	if (iblock > ee_block) {
@@ -2272,6 +2286,38 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 	/* ex3: to ee_block + ee_len : uninitialised */
 	if (allocated > max_blocks) {
 		unsigned int newdepth;
+		/* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */
+		if (allocated <= EXT4_EXT_ZERO_LEN) {
+			/* Mark first half uninitialized.
+			 * Mark second half initialized and zero out the
+			 * initialized extent
+			 */
+			ex->ee_block = orig_ex.ee_block;
+			ex->ee_len   = cpu_to_le16(ee_len - allocated);
+			ext4_ext_mark_uninitialized(ex);
+			ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
+			ext4_ext_dirty(handle, inode, path + depth);
+
+			ex3 = &newex;
+			ex3->ee_block = cpu_to_le32(iblock);
+			ext4_ext_store_pblock(ex3, newblock);
+			ex3->ee_len = cpu_to_le16(allocated);
+			err = ext4_ext_insert_extent(handle, inode, path, ex3);
+			if (err == -ENOSPC) {
+				err =  ext4_ext_zeroout(inode, &orig_ex);
+				if (err)
+					goto fix_extent_len;
+				ex->ee_block = orig_ex.ee_block;
+				ex->ee_len   = orig_ex.ee_len;
+				ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
+				ext4_ext_dirty(handle, inode, path + depth);
+				return le16_to_cpu(ex->ee_len);
+
+			} else if (err)
+				goto fix_extent_len;
+
+			return allocated;
+		}
 		ex3 = &newex;
 		ex3->ee_block = cpu_to_le32(iblock + max_blocks);
 		ext4_ext_store_pblock(ex3, newblock + max_blocks);
@@ -2320,6 +2366,23 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 				goto out;
 		}
 		allocated = max_blocks;
+
+		/* If extent has less than EXT4_EXT_ZERO_LEN and we are trying
+		 * to insert a extent in the middle zerout directly
+		 * otherwise give the extent a chance to merge to left
+		 */
+		if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN &&
+							iblock != ee_block) {
+			err =  ext4_ext_zeroout(inode, &orig_ex);
+			if (err)
+				goto fix_extent_len;
+			/* update the extent length and mark as initialized */
+			ex->ee_block = orig_ex.ee_block;
+			ex->ee_len   = orig_ex.ee_len;
+			ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
+			ext4_ext_dirty(handle, inode, path + depth);
+			return le16_to_cpu(ex->ee_len);
+		}
 	}
 	/*
 	 * If there was a change of depth as part of the