1 files changed, 15 insertions, 1 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index d2584224c89a..a6307f7c9807 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -144,9 +144,17 @@ struct ext4_allocation_request {
 #define EXT4_MAP_UNWRITTEN      (1 << BH_Unwritten)
 #define EXT4_MAP_BOUNDARY       (1 << BH_Boundary)
 #define EXT4_MAP_UNINIT         (1 << BH_Uninit)
+/* Sometimes (in the bigalloc case, from ext4_da_get_block_prep) the caller of
+ * ext4_map_blocks wants to know whether or not the underlying cluster has
+ * already been accounted for. EXT4_MAP_FROM_CLUSTER conveys to the caller that
+ * the requested mapping was from previously mapped (or delayed allocated)
+ * cluster. We use BH_AllocFromCluster only for this flag. BH_AllocFromCluster
+ * should never appear on buffer_head's state flags.
+ */
+#define EXT4_MAP_FROM_CLUSTER   (1 << BH_AllocFromCluster)
 #define EXT4_MAP_FLAGS          (EXT4_MAP_NEW | EXT4_MAP_MAPPED |\
                                  EXT4_MAP_UNWRITTEN | EXT4_MAP_BOUNDARY |\
-                                 EXT4_MAP_UNINIT)
+                                 EXT4_MAP_UNINIT | EXT4_MAP_FROM_CLUSTER)
 
 struct ext4_map_blocks {
         ext4_fsblk_t m_pblk;
@@ -1884,6 +1892,7 @@ extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
 extern qsize_t *ext4_get_reserved_space(struct inode *inode);
 extern void ext4_da_update_reserve_space(struct inode *inode,
                                         int used, int quota_claim);
+extern int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock);
 
 /* indirect.c */
 extern int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
@@ -2284,6 +2293,11 @@ extern int ext4_multi_mount_protect(struct super_block *, ext4_fsblk_t);
 enum ext4_state_bits {
         BH_Uninit       /* blocks are allocated but uninitialized on disk */
           = BH_JBDPrivateStart,
+        BH_AllocFromCluster,    /* allocated blocks were part of already
+                                 * allocated cluster. Note that this flag will
+                                 * never, ever appear in a buffer_head's state
+                                 * flag. See EXT4_MAP_FROM_CLUSTER to see where
+                                 * this is used. */
 };
 
 BUFFER_FNS(Uninit, uninit)