Btrfs: improve inode hash function/inode lookup

[linux-block.git] / fs / btrfs / btrfs_inode.h

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 71f074e1870b2e9fe183cf338ad2515314155e6e..ac0b39db27d175af15a718a41ac2ebf11c32150f 100644 (file)
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -19,6 +19,7 @@
 #ifndef __BTRFS_I__
 #define __BTRFS_I__
 
+#include <linux/hash.h>
 #include "extent_map.h"
 #include "extent_io.h"
 #include "ordered-data.h"
@@ -179,6 +180,25 @@ static inline struct btrfs_inode *BTRFS_I(struct inode *inode)
        return container_of(inode, struct btrfs_inode, vfs_inode);
 }
 
+static inline unsigned long btrfs_inode_hash(u64 objectid,
+                                            const struct btrfs_root *root)
+{
+       u64 h = objectid ^ (root->objectid * GOLDEN_RATIO_PRIME);
+
+#if BITS_PER_LONG == 32
+       h = (h >> 32) ^ (h & 0xffffffff);
+#endif
+
+       return (unsigned long)h;
+}
+
+static inline void btrfs_insert_inode_hash(struct inode *inode)
+{
+       unsigned long h = btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root);
+
+       __insert_inode_hash(inode, h);
+}
+
 static inline u64 btrfs_ino(struct inode *inode)
 {
        u64 ino = BTRFS_I(inode)->location.objectid;