vfs: add find_inode_nowait() function

Add a new function find_inode_nowait() which is an even more general
version of ilookup5_nowait().  It is designed for callers which need
very fine grained control over when the function is allowed to block
or increment the inode's reference count.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cd027ce..5ea8b6e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2441,6 +2441,11 @@
 
 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
 extern struct inode * iget_locked(struct super_block *, unsigned long);
+extern struct inode *find_inode_nowait(struct super_block *,
+				       unsigned long,
+				       int (*match)(struct inode *,
+						    unsigned long, void *),
+				       void *data);
 extern int insert_inode_locked4(struct inode *, unsigned long, int (*test)(struct inode *, void *), void *);
 extern int insert_inode_locked(struct inode *);
 #ifdef CONFIG_DEBUG_LOCK_ALLOC