ext4: cleanup block allocator

Move the code related to block allocation to a single function and add helper
funtions to differient allocation for data and meta data blocks

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

5 files changed, 84 insertions, 59 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 816f1dbaeb3c..48787e86d438 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1640,20 +1640,24 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries)
 }
 
 /**
- * ext4_new_blocks_old() -- core block(s) allocation function
+ * ext4_old_new_blocks() -- core block bitmap based block allocation function
+ *
  * @handle:             handle to this transaction
  * @inode:              file inode
  * @goal:               given target block(filesystem wide)
  * @count:              target number of blocks to allocate
  * @errp:               error code
  *
- * ext4_new_blocks uses a goal block to assist allocation.  It tries to
- * allocate block(s) from the block group contains the goal block first. If that
- * fails, it will try to allocate block(s) from other block groups without
- * any specific goal block.
+ * ext4_old_new_blocks uses a goal block to assist allocation and look up
+ * the block bitmap directly to do block allocation.  It tries to
+ * allocate block(s) from the block group contains the goal block first. If
+ * that fails, it will try to allocate block(s) from other block groups
+ * without any specific goal block.
+ *
+ * This function is called when -o nomballoc mount option is enabled
  *
  */
-ext4_fsblk_t ext4_new_blocks_old(handle_t *handle, struct inode *inode,
+ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
                         ext4_fsblk_t goal, unsigned long *count, int *errp)
 {
         struct buffer_head *bitmap_bh = NULL;
@@ -1923,78 +1927,95 @@ out:
         return 0;
 }
 
-ext4_fsblk_t ext4_new_meta_block(handle_t *handle, struct inode *inode,
-                ext4_fsblk_t goal, int *errp)
-{
-        struct ext4_allocation_request ar;
-        ext4_fsblk_t ret;
-
-        if (!test_opt(inode->i_sb, MBALLOC)) {
-                unsigned long count = 1;
-                ret = ext4_new_blocks_old(handle, inode, goal, &count, errp);
-                return ret;
-        }
+#define EXT4_META_BLOCK 0x1
 
-        memset(&ar, 0, sizeof(ar));
-        ar.inode = inode;
-        ar.goal = goal;
-        ar.len = 1;
-        ret = ext4_mb_new_blocks(handle, &ar, errp);
-        return ret;
-}
-ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
-                ext4_fsblk_t goal, unsigned long *count, int *errp)
-{
-        struct ext4_allocation_request ar;
-        ext4_fsblk_t ret;
-
-        if (!test_opt(inode->i_sb, MBALLOC)) {
-                ret = ext4_new_blocks_old(handle, inode, goal, count, errp);
-                return ret;
-        }
-
-        memset(&ar, 0, sizeof(ar));
-        ar.inode = inode;
-        ar.goal = goal;
-        ar.len = *count;
-        ret = ext4_mb_new_blocks(handle, &ar, errp);
-        *count = ar.len;
-        return ret;
-}
-
-ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode,
+static ext4_fsblk_t do_blk_alloc(handle_t *handle, struct inode *inode,
                                 ext4_lblk_t iblock, ext4_fsblk_t goal,
-                                unsigned long *count, int *errp)
+                                unsigned long *count, int *errp, int flags)
 {
         struct ext4_allocation_request ar;
         ext4_fsblk_t ret;
 
         if (!test_opt(inode->i_sb, MBALLOC)) {
-                ret = ext4_new_blocks_old(handle, inode, goal, count, errp);
-                return ret;
+                return ext4_old_new_blocks(handle, inode, goal, count, errp);
         }
 
         memset(&ar, 0, sizeof(ar));
         /* Fill with neighbour allocated blocks */
-        ar.lleft  = 0;
-        ar.pleft  = 0;
-        ar.lright = 0;
-        ar.pright = 0;
 
         ar.inode = inode;
         ar.goal = goal;
         ar.len = *count;
         ar.logical = iblock;
-        if (S_ISREG(inode->i_mode))
+
+        if (S_ISREG(inode->i_mode) && !(flags & EXT4_META_BLOCK))
+                /* enable in-core preallocation for data block allocation */
                 ar.flags = EXT4_MB_HINT_DATA;
         else
                 /* disable in-core preallocation for non-regular files */
                 ar.flags = 0;
+
         ret = ext4_mb_new_blocks(handle, &ar, errp);
         *count = ar.len;
         return ret;
 }
 
+/*
+ * ext4_new_meta_block() -- allocate block for meta data (indexing) blocks
+ *
+ * @handle:             handle to this transaction
+ * @inode:              file inode
+ * @goal:               given target block(filesystem wide)
+ * @errp:               error code
+ *
+ * Return allocated block number on success
+ */
+ext4_fsblk_t ext4_new_meta_block(handle_t *handle, struct inode *inode,
+                ext4_fsblk_t goal, int *errp)
+{
+        unsigned long count = 1;
+        return do_blk_alloc(handle, inode, 0, goal,
+                        &count, errp, EXT4_META_BLOCK);
+}
+
+/*
+ * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
+ *
+ * @handle:             handle to this transaction
+ * @inode:              file inode
+ * @goal:               given target block(filesystem wide)
+ * @count:              total number of blocks need
+ * @errp:               error code
+ *
+ * Return 1st allocated block numberon success, *count stores total account
+ * error stores in errp pointer
+ */
+ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
+                ext4_fsblk_t goal, unsigned long *count, int *errp)
+{
+        return do_blk_alloc(handle, inode, 0, goal,
+                        count, errp, EXT4_META_BLOCK);
+}
+
+/*
+ * ext4_new_blocks() -- allocate data blocks
+ *
+ * @handle:             handle to this transaction
+ * @inode:              file inode
+ * @goal:               given target block(filesystem wide)
+ * @count:              total number of blocks need
+ * @errp:               error code
+ *
+ * Return 1st allocated block numberon success, *count stores total account
+ * error stores in errp pointer
+ */
+
+ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode,
+                                ext4_lblk_t iblock, ext4_fsblk_t goal,
+                                unsigned long *count, int *errp)
+{
+        return do_blk_alloc(handle, inode, iblock, goal, count, errp, 0);
+}
 
 /**
  * ext4_count_free_blocks() -- count filesystem free blocks
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index d44a7fb6a7b1..e622ade69d5c 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -977,7 +977,7 @@ extern ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
 extern ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode,
                                         ext4_lblk_t iblock, ext4_fsblk_t goal,
                                         unsigned long *count, int *errp);
-extern ext4_fsblk_t ext4_new_blocks_old(handle_t *handle, struct inode *inode,
+extern ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
                         ext4_fsblk_t goal, unsigned long *count, int *errp);
 extern void ext4_free_blocks (handle_t *handle, struct inode *inode,
                         ext4_fsblk_t block, unsigned long count, int metadata);
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index c729b3507b46..555155d239df 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -179,8 +179,11 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
         return bg_start + colour + block;
 }
 
+/*
+ * Allocation for a meta data block
+ */
 static ext4_fsblk_t
-ext4_ext_new_block(handle_t *handle, struct inode *inode,
+ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
                         struct ext4_ext_path *path,
                         struct ext4_extent *ex, int *err)
 {
@@ -690,7 +693,8 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
         /* allocate all needed blocks */
         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
         for (a = 0; a < depth - at; a++) {
-                newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
+                newblock = ext4_ext_new_meta_block(handle, inode, path,
+                                                   newext, &err);
                 if (newblock == 0)
                         goto cleanup;
                 ablocks[a] = newblock;
@@ -886,7 +890,7 @@ static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
         ext4_fsblk_t newblock;
         int err = 0;
 
-        newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
+        newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err);
         if (newblock == 0)
                 return err;
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index bc950562b5ba..c5d506dce8c5 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -561,7 +561,7 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
                 goto allocated;
         /* Now allocate data blocks */
         count = target;
-        /* allocating blocks for indirect blocks and direct blocks */
+        /* allocating blocks for data blocks */
         current_block = ext4_new_blocks(handle, inode, iblock,
                                                 goal, &count, err);
         if (*err && (target == blks)) {
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index cde232bdaed0..816ba8cce79a 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4041,7 +4041,7 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
         sbi = EXT4_SB(sb);
 
         if (!test_opt(sb, MBALLOC)) {
-                block = ext4_new_blocks_old(handle, ar->inode, ar->goal,
+                block = ext4_old_new_blocks(handle, ar->inode, ar->goal,
                                             &(ar->len), errp);
                 return block;
         }