fuse: fix page invalidation

Other than truncate, there are two cases, when fuse tries to get rid
of cached pages:

 a) in open, if KEEP_CACHE flag is not set
 b) in getattr, if file size changed spontaneously

Until now invalidate_mapping_pages() were used, which didn't get rid
of mapped pages.  This is wrong, and becomes more wrong as dirty pages
are introduced.  So instead properly invalidate all pages with
invalidate_inode_pages2().
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fuse/file.c

@@ -87,7 +87,7 @@ void fuse_finish_open(struct inode *inode, struct file *file,
 	if (outarg->open_flags & FOPEN_DIRECT_IO)
 		file->f_op = &fuse_direct_io_file_operations;
 	if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
-		invalidate_mapping_pages(inode->i_mapping, 0, -1);
+		invalidate_inode_pages2(inode->i_mapping);
 	ff->fh = outarg->fh;
 	file->private_data = fuse_file_get(ff);
 }

fs/fuse/inode.c

@@ -143,7 +143,7 @@ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
 	if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
 		if (attr->size < oldsize)
 			fuse_truncate(inode->i_mapping, attr->size);
-		invalidate_mapping_pages(inode->i_mapping, 0, -1);
+		invalidate_inode_pages2(inode->i_mapping);
 	}
 }