ext4: delayed allocation ENOSPC handling

[mirror_ubuntu-bionic-kernel.git] / fs / ext4 / extents.c

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 7844bbb2bac0ed700d25ecf13267aa6696ef2af2..dabc3b68d2498ded2e980544cbb7e8f559755928 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -248,6 +248,36 @@ static int ext4_ext_space_root_idx(struct inode *inode)
        return size;
 }
 
+/*
+ * Calculate the number of metadata blocks needed
+ * to allocate @blocks
+ * Worse case is one block per extent
+ */
+int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks)
+{
+       int lcap, icap, rcap, leafs, idxs, num;
+       int newextents = blocks;
+
+       rcap = ext4_ext_space_root_idx(inode);
+       lcap = ext4_ext_space_block(inode);
+       icap = ext4_ext_space_block_idx(inode);
+
+       /* number of new leaf blocks needed */
+       num = leafs = (newextents + lcap - 1) / lcap;
+
+       /*
+        * Worse case, we need separate index block(s)
+        * to link all new leaf blocks
+        */
+       idxs = (leafs + icap - 1) / icap;
+       do {
+               num += idxs;
+               idxs = (idxs + icap - 1) / icap;
+       } while (idxs > rcap);
+
+       return num;
+}
+
 static int
 ext4_ext_max_entries(struct inode *inode, int depth)
 {
@@ -2910,7 +2940,7 @@ retry:
                }
                ret = ext4_get_blocks_wrap(handle, inode, block,
                                          max_blocks, &map_bh,
-                                         EXT4_CREATE_UNINITIALIZED_EXT, 0);
+                                         EXT4_CREATE_UNINITIALIZED_EXT, 0, 0);
                if (ret <= 0) {
 #ifdef EXT4FS_DEBUG
                        WARN_ON(ret <= 0);