3 files changed, 49 insertions, 62 deletions

diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
index 6c166c0a54b7..d33dc56d6986 100644
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -216,7 +216,9 @@ extern int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks);
 extern ext4_fsblk_t idx_pblock(struct ext4_extent_idx *);
 extern void ext4_ext_store_pblock(struct ext4_extent *, ext4_fsblk_t);
 extern int ext4_extent_tree_init(handle_t *, struct inode *);
-extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *);
+extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
+                                                   int num,
+                                                   struct ext4_ext_path *path);
 extern int ext4_ext_try_to_merge(struct inode *inode,
                                  struct ext4_ext_path *path,
                                  struct ext4_extent *);
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 7212947a8ca3..5c5dd3a1d657 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1747,54 +1747,61 @@ static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
 }
 
 /*
- * ext4_ext_calc_credits_for_insert:
- * This routine returns max. credits that the extent tree can consume.
- * It should be OK for low-performance paths like ->writepage()
- * To allow many writing processes to fit into a single transaction,
- * the caller should calculate credits under i_data_sem and
- * pass the actual path.
+ * ext4_ext_calc_credits_for_single_extent:
+ * This routine returns max. credits that needed to insert an extent
+ * to the extent tree.
+ * When pass the actual path, the caller should calculate credits
+ * under i_data_sem.
  */
-int ext4_ext_calc_credits_for_insert(struct inode *inode,
+int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int num,
                                                 struct ext4_ext_path *path)
 {
-        int depth, needed;
-
         if (path) {
+                int depth = ext_depth(inode);
+                int ret;
+
                 /* probably there is space in leaf? */
-                depth = ext_depth(inode);
                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
-                                < le16_to_cpu(path[depth].p_hdr->eh_max))
-                        return 1;
-        }
+                                < le16_to_cpu(path[depth].p_hdr->eh_max)) {
 
-        /*
-         * given 32-bit logical block (4294967296 blocks), max. tree
-         * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
-         * Let's also add one more level for imbalance.
-         */
-        depth = 5;
-
-        /* allocation of new data block(s) */
-        needed = 2;
+                        /*
+                         *  There are some space in the leaf tree, no
+                         *  need to account for leaf block credit
+                         *
+                         *  bitmaps and block group descriptor blocks
+                         *  and other metadat blocks still need to be
+                         *  accounted.
+                         */
+                        /* 1 one bitmap, 1 block group descriptor */
+                        ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
+                }
+        }
 
-        /*
-         * tree can be full, so it would need to grow in depth:
-         * we need one credit to modify old root, credits for
-         * new root will be added in split accounting
-         */
-        needed += 1;
+        return ext4_meta_trans_blocks(inode, num, 1);
+}
 
-        /*
-         * Index split can happen, we would need:
-         *    allocate intermediate indexes (bitmap + group)
-         *  + change two blocks at each level, but root (already included)
-         */
-        needed += (depth * 2) + (depth * 2);
+/*
+ * How many index/leaf blocks need to change/allocate to modify nrblocks?
+ *
+ * if nrblocks are fit in a single extent (chunk flag is 1), then
+ * in the worse case, each tree level index/leaf need to be changed
+ * if the tree split due to insert a new extent, then the old tree
+ * index/leaf need to be updated too
+ *
+ * If the nrblocks are discontiguous, they could cause
+ * the whole tree split more than once, but this is really rare.
+ */
+int ext4_ext_index_trans_blocks(struct inode *inode, int num, int chunk)
+{
+        int index;
+        int depth = ext_depth(inode);
 
-        /* any allocation modifies superblock */
-        needed += 1;
+        if (chunk)
+                index = depth * 2;
+        else
+                index = depth * 3;
 
-        return needed;
+        return index;
 }
 
 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
@@ -1921,9 +1928,7 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
                         correct_index = 1;
                         credits += (ext_depth(inode)) + 1;
                 }
-#ifdef CONFIG_QUOTA
                 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
-#endif
 
                 err = ext4_ext_journal_restart(handle, credits);
                 if (err)
@@ -2858,27 +2863,6 @@ out_stop:
         ext4_journal_stop(handle);
 }
 
-/*
- * ext4_ext_writepage_trans_blocks:
- * calculate max number of blocks we could modify
- * in order to allocate new block for an inode
- */
-int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
-{
-        int needed;
-
-        needed = ext4_ext_calc_credits_for_insert(inode, NULL);
-
-        /* caller wants to allocate num blocks, but note it includes sb */
-        needed = needed * num - (num - 1);
-
-#ifdef CONFIG_QUOTA
-        needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
-#endif
-
-        return needed;
-}
-
 static void ext4_falloc_update_inode(struct inode *inode,
                                 int mode, loff_t new_size, int update_ctime)
 {
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index b9e077ba07e9..46fc0b5b12ba 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -53,7 +53,8 @@ static int finish_range(handle_t *handle, struct inode *inode,
          * credit. But below we try to not accumalate too much
          * of them by restarting the journal.
          */
-        needed = ext4_ext_calc_credits_for_insert(inode, path);
+        needed = ext4_ext_calc_credits_for_single_extent(inode,
+                    lb->last_block - lb->first_block + 1, path);
 
         /*
          * Make sure the credit we accumalated is not really high