1 files changed, 53 insertions, 17 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 91ae46098ea4..765a4826b118 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -296,29 +296,44 @@ static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
  * to allocate @blocks
  * Worse case is one block per extent
  */
-int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks)
+int ext4_ext_calc_metadata_amount(struct inode *inode, sector_t lblock)
 {
-        int lcap, icap, rcap, leafs, idxs, num;
-        int newextents = blocks;
-
-        rcap = ext4_ext_space_root_idx(inode, 0);
-        lcap = ext4_ext_space_block(inode, 0);
-        icap = ext4_ext_space_block_idx(inode, 0);
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        int idxs, num = 0;
 
-        /* number of new leaf blocks needed */
-        num = leafs = (newextents + lcap - 1) / lcap;
+        idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
+                / sizeof(struct ext4_extent_idx));
 
         /*
-         * Worse case, we need separate index block(s)
-         * to link all new leaf blocks
+         * If the new delayed allocation block is contiguous with the
+         * previous da block, it can share index blocks with the
+         * previous block, so we only need to allocate a new index
+         * block every idxs leaf blocks.  At ldxs**2 blocks, we need
+         * an additional index block, and at ldxs**3 blocks, yet
+         * another index blocks.
          */
-        idxs = (leafs + icap - 1) / icap;
-        do {
-                num += idxs;
-                idxs = (idxs + icap - 1) / icap;
-        } while (idxs > rcap);
+        if (ei->i_da_metadata_calc_len &&
+            ei->i_da_metadata_calc_last_lblock+1 == lblock) {
+                if ((ei->i_da_metadata_calc_len % idxs) == 0)
+                        num++;
+                if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
+                        num++;
+                if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
+                        num++;
+                        ei->i_da_metadata_calc_len = 0;
+                } else
+                        ei->i_da_metadata_calc_len++;
+                ei->i_da_metadata_calc_last_lblock++;
+                return num;
+        }
 
-        return num;
+        /*
+         * In the worst case we need a new set of index blocks at
+         * every level of the inode's extent tree.
+         */
+        ei->i_da_metadata_calc_len = 1;
+        ei->i_da_metadata_calc_last_lblock = lblock;
+        return ext_depth(inode) + 1;
 }
 
 static int
@@ -3117,7 +3132,19 @@ out:
                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
                                         newblock + max_blocks,
                                         allocated - max_blocks);
+                allocated = max_blocks;
         }
+
+        /*
+         * If we have done fallocate with the offset that is already
+         * delayed allocated, we would have block reservation
+         * and quota reservation done in the delayed write path.
+         * But fallocate would have already updated quota and block
+         * count for this offset. So cancel these reservation
+         */
+        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
+                ext4_da_update_reserve_space(inode, allocated, 0);
+
 map_out:
         set_buffer_mapped(bh_result);
 out1:
@@ -3353,9 +3380,18 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         /* previous routine could use block we allocated */
         newblock = ext_pblock(&newex);
         allocated = ext4_ext_get_actual_len(&newex);
+        if (allocated > max_blocks)
+                allocated = max_blocks;
         set_buffer_new(bh_result);
 
         /*
+         * Update reserved blocks/metadata blocks after successful
+         * block allocation which had been deferred till now.
+         */
+        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
+                ext4_da_update_reserve_space(inode, allocated, 1);
+
+        /*
          * Cache the extent and update transaction to commit on fdatasync only
          * when it is _not_ an uninitialized extent.
          */