fuse: generic_write_checks() for direct_io

This fixes O_APPEND in direct IO mode.  Also checks writes against file size
limits, notably rlimits.

Reported by Greg Bruno.

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>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index d0ed60b..adf7995 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -610,7 +610,9 @@
 	ssize_t res;
 	/* Don't allow parallel writes to the same file */
 	mutex_lock(&inode->i_mutex);
-	res = fuse_direct_io(file, buf, count, ppos, 1);
+	res = generic_write_checks(file, ppos, &count, 0);
+	if (!res)
+		res = fuse_direct_io(file, buf, count, ppos, 1);
 	mutex_unlock(&inode->i_mutex);
 	return res;
 }