1 files changed, 48 insertions, 0 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 264f6949511..f8224adf496 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -620,3 +620,51 @@ unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
 
 }
 
+/**
+ *      ext4_inode_to_goal_block - return a hint for block allocation
+ *      @inode: inode for block allocation
+ *
+ *      Return the ideal location to start allocating blocks for a
+ *      newly created inode.
+ */
+ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
+{
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        ext4_group_t block_group;
+        ext4_grpblk_t colour;
+        int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
+        ext4_fsblk_t bg_start;
+        ext4_fsblk_t last_block;
+
+        block_group = ei->i_block_group;
+        if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
+                /*
+                 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
+                 * block groups per flexgroup, reserve the first block
+                 * group for directories and special files.  Regular
+                 * files will start at the second block group.  This
+                 * tends to speed up directory access and improves
+                 * fsck times.
+                 */
+                block_group &= ~(flex_size-1);
+                if (S_ISREG(inode->i_mode))
+                        block_group++;
+        }
+        bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
+        last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
+
+        /*
+         * If we are doing delayed allocation, we don't need take
+         * colour into account.
+         */
+        if (test_opt(inode->i_sb, DELALLOC))
+                return bg_start;
+
+        if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
+                colour = (current->pid % 16) *
+                        (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
+        else
+                colour = (current->pid % 16) * ((last_block - bg_start) / 16);
+        return bg_start + colour;
+}
+