Btrfs: Add mount option to enforce a max extent size

[linux-2.6-block.git] / fs / btrfs / inode.c

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 91f3fc43e2a98c2a89c1e36981e4f10c15019309..686dd03f34f25d8d6fc0e17c6116e71672592b3f 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -78,6 +78,7 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end)
        struct btrfs_trans_handle *trans;
        u64 alloc_hint = 0;
        u64 num_bytes;
+       u64 cur_alloc_size;
        u64 blocksize = root->sectorsize;
        struct btrfs_key ins;
        int ret;
@@ -94,17 +95,24 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end)
        if (alloc_hint == EXTENT_MAP_INLINE)
                goto out;
 
-       ret = btrfs_alloc_extent(trans, root, num_bytes,
-                                root->root_key.objectid, trans->transid,
-                                inode->i_ino, start, 0,
-                                alloc_hint, (u64)-1, &ins, 1);
-       if (ret) {
-               WARN_ON(1);
-               goto out;
+       while(num_bytes > 0) {
+               cur_alloc_size = min(num_bytes, root->fs_info->max_extent);
+               ret = btrfs_alloc_extent(trans, root, cur_alloc_size,
+                                        root->root_key.objectid,
+                                        trans->transid,
+                                        inode->i_ino, start, 0,
+                                        alloc_hint, (u64)-1, &ins, 1);
+               if (ret) {
+                       WARN_ON(1);
+                       goto out;
+               }
+               ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
+                                              start, ins.objectid, ins.offset,
+                                              ins.offset);
+               num_bytes -= cur_alloc_size;
+               alloc_hint = ins.objectid + ins.offset;
+               start += cur_alloc_size;
        }
-       ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
-                                      start, ins.objectid, ins.offset,
-                                      ins.offset);
 out:
        btrfs_end_transaction(trans, root);
        return ret;