fs: do not assign default i_ino in new_inode

Instead of always assigning an increasing inode number in new_inode
move the call to assign it into those callers that actually need it.
For now callers that need it is estimated conservatively, that is
the call is added to all filesystems that do not assign an i_ino
by themselves.  For a few more filesystems we can avoid assigning
any inode number given that they aren't user visible, and for others
it could be done lazily when an inode number is actually needed,
but that's left for later patches.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/inode.c b/fs/inode.c
index 46a3e12..2cd2e48 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -735,7 +735,7 @@
 #define LAST_INO_BATCH 1024
 static DEFINE_PER_CPU(unsigned int, last_ino);
 
-static unsigned int get_next_ino(void)
+unsigned int get_next_ino(void)
 {
 	unsigned int *p = &get_cpu_var(last_ino);
 	unsigned int res = *p;
@@ -753,6 +753,7 @@
 	put_cpu_var(last_ino);
 	return res;
 }
+EXPORT_SYMBOL(get_next_ino);
 
 /**
  *	new_inode 	- obtain an inode
@@ -776,7 +777,6 @@
 	if (inode) {
 		spin_lock(&inode_lock);
 		__inode_sb_list_add(inode);
-		inode->i_ino = get_next_ino();
 		inode->i_state = 0;
 		spin_unlock(&inode_lock);
 	}