[PATCH] kill ->put_inode

And with that last patch to affs killing the last put_inode instance we
can finally, after many years of transition kill this racy and awkward
interface.

(It's kinda funny that even the description in
Documentation/filesystems/vfs.txt was entirely wrong..)

Also remove a very misleading comment above the defintion of
struct super_operations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Documentation/filesystems/Locking

@@ -92,7 +92,6 @@ prototypes:
 	void (*destroy_inode)(struct inode *);
 	void (*dirty_inode) (struct inode *);
 	int (*write_inode) (struct inode *, int);
-	void (*put_inode) (struct inode *);
 	void (*drop_inode) (struct inode *);
 	void (*delete_inode) (struct inode *);
 	void (*put_super) (struct super_block *);
@@ -115,7 +114,6 @@ alloc_inode:		no	no	no
 destroy_inode:		no
 dirty_inode:		no				(must not sleep)
 write_inode:		no
-put_inode:		no
 drop_inode:		no				!!!inode_lock!!!
 delete_inode:		no
 put_super:		yes	yes	no

Documentation/filesystems/vfs.txt

@@ -205,7 +205,6 @@ struct super_operations {
 
         void (*dirty_inode) (struct inode *);
         int (*write_inode) (struct inode *, int);
-        void (*put_inode) (struct inode *);
         void (*drop_inode) (struct inode *);
         void (*delete_inode) (struct inode *);
         void (*put_super) (struct super_block *);
@@ -246,9 +245,6 @@ or bottom half).
 	inode to disc.  The second parameter indicates whether the write
 	should be synchronous or not, not all filesystems check this flag.
 
-  put_inode: called when the VFS inode is removed from the inode
-	cache.
-
   drop_inode: called when the last access to the inode is dropped,
 	with the inode_lock spinlock held.
 

fs/inode.c

@@ -1153,9 +1153,6 @@ void iput(struct inode *inode)
 
 		BUG_ON(inode->i_state == I_CLEAR);
 
-		if (op && op->put_inode)
-			op->put_inode(inode);
-
 		if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
 			iput_final(inode);
 	}

include/linux/fs.h

@@ -1289,17 +1289,12 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
 extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
 		unsigned long, loff_t *);
 
-/*
- * NOTE: write_inode, delete_inode, clear_inode, put_inode can be called
- * without the big kernel lock held in all filesystems.
- */
 struct super_operations {
    	struct inode *(*alloc_inode)(struct super_block *sb);
 	void (*destroy_inode)(struct inode *);
 
    	void (*dirty_inode) (struct inode *);
 	int (*write_inode) (struct inode *, int);
-	void (*put_inode) (struct inode *);
 	void (*drop_inode) (struct inode *);
 	void (*delete_inode) (struct inode *);
 	void (*put_super) (struct super_block *);