ext4: refactor duplicated block placement code
Eric Sandeen [Tue, 28 Jun 2011 14:01:31 +0000 (10:01 -0400)]
I found that ext4_ext_find_goal() and ext4_find_near()
share the same code for returning a coloured start block
based on i_block_group.

We can refactor this into a common function so that they
don't diverge in the future.

Thanks to adilger for suggesting the new function name.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/balloc.c
fs/ext4/ext4.h
fs/ext4/extents.c
fs/ext4/indirect.c

index 264f694..f8224ad 100644 (file)
@@ -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;
+}
+
index ddaf504..49d2cea 100644 (file)
@@ -1743,6 +1743,7 @@ extern unsigned ext4_init_block_bitmap(struct super_block *sb,
                                       struct ext4_group_desc *desc);
 #define ext4_free_blocks_after_init(sb, group, desc)                   \
                ext4_init_block_bitmap(sb, NULL, group, desc)
+ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);
 
 /* dir.c */
 extern int __ext4_check_dir_entry(const char *, unsigned int, struct inode *,
index eb63c7b..f331e50 100644 (file)
@@ -114,12 +114,6 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
                              struct ext4_ext_path *path,
                              ext4_lblk_t block)
 {
-       struct ext4_inode_info *ei = EXT4_I(inode);
-       ext4_fsblk_t bg_start;
-       ext4_fsblk_t last_block;
-       ext4_grpblk_t colour;
-       ext4_group_t block_group;
-       int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
        int depth;
 
        if (path) {
@@ -161,36 +155,7 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
        }
 
        /* OK. use inode's group */
-       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 + block;
+       return ext4_inode_to_goal_block(inode);
 }
 
 /*
index c3e85a8..6c27111 100644 (file)
@@ -207,11 +207,6 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
        struct ext4_inode_info *ei = EXT4_I(inode);
        __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
        __le32 *p;
-       ext4_fsblk_t bg_start;
-       ext4_fsblk_t last_block;
-       ext4_grpblk_t colour;
-       ext4_group_t block_group;
-       int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
 
        /* Try to find previous block */
        for (p = ind->p - 1; p >= start; p--) {
@@ -227,28 +222,7 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
         * It is going to be referred to from the inode itself? OK, just put it
         * into the same cylinder group then.
         */
-       block_group = ei->i_block_group;
-       if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
-               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;
+       return ext4_inode_to_goal_block(inode);
 }
 
 /**