fs: Factor inode hash operations into functions

Before replacing the inode hash locking with a more scalable
mechanism, factor the removal of the inode from the hashes rather
than open coding it in several places.

Based on a patch originally from Nick Piggin.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/inode.c b/fs/inode.c
index 3bdc76f..5e5bafe 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -336,6 +336,58 @@ static void inode_lru_list_del(struct inode *inode)
        }
 }
 
+static unsigned long hash(struct super_block *sb, unsigned long hashval)
+{
+       unsigned long tmp;
+
+       tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
+                       L1_CACHE_BYTES;
+       tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
+       return tmp & I_HASHMASK;
+}
+
+/**
+ *     __insert_inode_hash - hash an inode
+ *     @inode: unhashed inode
+ *     @hashval: unsigned long value used to locate this object in the
+ *             inode_hashtable.
+ *
+ *     Add an inode to the inode hash for this superblock.
+ */
+void __insert_inode_hash(struct inode *inode, unsigned long hashval)
+{
+       struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
+       spin_lock(&inode_lock);
+       hlist_add_head(&inode->i_hash, head);
+       spin_unlock(&inode_lock);
+}
+EXPORT_SYMBOL(__insert_inode_hash);
+
+/**
+ *     __remove_inode_hash - remove an inode from the hash
+ *     @inode: inode to unhash
+ *
+ *     Remove an inode from the superblock.
+ */
+static void __remove_inode_hash(struct inode *inode)
+{
+       hlist_del_init(&inode->i_hash);
+}
+
+/**
+ *     remove_inode_hash - remove an inode from the hash
+ *     @inode: inode to unhash
+ *
+ *     Remove an inode from the superblock.
+ */
+void remove_inode_hash(struct inode *inode)
+{
+       spin_lock(&inode_lock);
+       hlist_del_init(&inode->i_hash);
+       spin_unlock(&inode_lock);
+}
+EXPORT_SYMBOL(remove_inode_hash);
+
 void end_writeback(struct inode *inode)
 {
        might_sleep();
@@ -383,7 +435,7 @@ static void dispose_list(struct list_head *head)
                evict(inode);
 
                spin_lock(&inode_lock);
-               hlist_del_init(&inode->i_hash);
+               __remove_inode_hash(inode);
                list_del_init(&inode->i_sb_list);
                spin_unlock(&inode_lock);
 
@@ -634,16 +686,6 @@ repeat:
        return node ? inode : NULL;
 }
 
-static unsigned long hash(struct super_block *sb, unsigned long hashval)
-{
-       unsigned long tmp;
-
-       tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
-                       L1_CACHE_BYTES;
-       tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
-       return tmp & I_HASHMASK;
-}
-
 static inline void
 __inode_add_to_lists(struct super_block *sb, struct hlist_head *head,
                        struct inode *inode)
@@ -1194,36 +1236,6 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
 }
 EXPORT_SYMBOL(insert_inode_locked4);
 
-/**
- *     __insert_inode_hash - hash an inode
- *     @inode: unhashed inode
- *     @hashval: unsigned long value used to locate this object in the
- *             inode_hashtable.
- *
- *     Add an inode to the inode hash for this superblock.
- */
-void __insert_inode_hash(struct inode *inode, unsigned long hashval)
-{
-       struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
-       spin_lock(&inode_lock);
-       hlist_add_head(&inode->i_hash, head);
-       spin_unlock(&inode_lock);
-}
-EXPORT_SYMBOL(__insert_inode_hash);
-
-/**
- *     remove_inode_hash - remove an inode from the hash
- *     @inode: inode to unhash
- *
- *     Remove an inode from the superblock.
- */
-void remove_inode_hash(struct inode *inode)
-{
-       spin_lock(&inode_lock);
-       hlist_del_init(&inode->i_hash);
-       spin_unlock(&inode_lock);
-}
-EXPORT_SYMBOL(remove_inode_hash);
 
 int generic_delete_inode(struct inode *inode)
 {
@@ -1279,7 +1291,7 @@ static void iput_final(struct inode *inode)
                spin_lock(&inode_lock);
                WARN_ON(inode->i_state & I_NEW);
                inode->i_state &= ~I_WILL_FREE;
-               hlist_del_init(&inode->i_hash);
+               __remove_inode_hash(inode);
        }
        WARN_ON(inode->i_state & I_NEW);
        inode->i_state |= I_FREEING;
@@ -1294,9 +1306,7 @@ static void iput_final(struct inode *inode)
        list_del_init(&inode->i_sb_list);
        spin_unlock(&inode_lock);
        evict(inode);
-       spin_lock(&inode_lock);
-       hlist_del_init(&inode->i_hash);
-       spin_unlock(&inode_lock);
+       remove_inode_hash(inode);
        wake_up_inode(inode);
        BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
        destroy_inode(inode);