fs: Add new pre-allocation ioctls to vfs for compatibility with legacy xfs ioctls

This patch adds ioctls to vfs for compatibility with legacy XFS
pre-allocation ioctls (XFS_IOC_*RESVP*). The implementation
effectively invokes sys_fallocate for the new ioctls.
Also handles the compat_ioctl case.
Note: These legacy ioctls are also implemented by OCFS2.

[AV: folded fixes from hch]

Signed-off-by: Ankit Jain <me@ankitjain.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1ff5e4e..79e302d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1906,6 +1906,8 @@
 
 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
 		       struct file *filp);
+extern int do_fallocate(struct file *file, int mode, loff_t offset,
+			loff_t len);
 extern long do_sys_open(int dfd, const char __user *filename, int flags,
 			int mode);
 extern struct file *filp_open(const char *, int, int);
@@ -1914,6 +1916,10 @@
 extern int filp_close(struct file *, fl_owner_t id);
 extern char * getname(const char __user *);
 
+/* fs/ioctl.c */
+
+extern int ioctl_preallocate(struct file *filp, void __user *argp);
+
 /* fs/dcache.c */
 extern void __init vfs_caches_init_early(void);
 extern void __init vfs_caches_init(unsigned long);