1 files changed, 20 insertions, 0 deletions

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 2a8c242bc4f5..d9b97d4960e6 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -40,6 +40,8 @@
 #define BTRFS_INODE_HAS_ASYNC_EXTENT            6
 #define BTRFS_INODE_NEEDS_FULL_SYNC             7
 #define BTRFS_INODE_COPY_EVERYTHING             8
+#define BTRFS_INODE_IN_DELALLOC_LIST            9
+#define BTRFS_INODE_READDIO_NEED_LOCK           10
 
 /* in memory btrfs inode */
 struct btrfs_inode {
@@ -216,4 +218,22 @@ static inline int btrfs_inode_in_log(struct inode *inode, u64 generation)
         return 0;
 }
 
+/*
+ * Disable DIO read nolock optimization, so new dio readers will be forced
+ * to grab i_mutex. It is used to avoid the endless truncate due to
+ * nonlocked dio read.
+ */
+static inline void btrfs_inode_block_unlocked_dio(struct inode *inode)
+{
+        set_bit(BTRFS_INODE_READDIO_NEED_LOCK, &BTRFS_I(inode)->runtime_flags);
+        smp_mb();
+}
+
+static inline void btrfs_inode_resume_unlocked_dio(struct inode *inode)
+{
+        smp_mb__before_clear_bit();
+        clear_bit(BTRFS_INODE_READDIO_NEED_LOCK,
+                  &BTRFS_I(inode)->runtime_flags);
+}
+
 #endif