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>

1 files changed, 55 insertions, 45 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 3bdc76f1653a..5e5bafe70ceb 100644
--- 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);