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>
        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);
 }
 
        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);
        }
 }