Ocfs2: handle hole punching via fallocate properly

This patch just makes ocfs2 use its UNRESERVP ioctl when we get the hole punch
flag in fallocate.  I didn't test it, but it seems simple enough.  Thanks,

Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ocfs2/file.c

@@ -1995,6 +1995,7 @@ static long ocfs2_fallocate(struct inode *inode, int mode, loff_t offset,
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 	struct ocfs2_space_resv sr;
 	int change_size = 1;
+	int cmd = OCFS2_IOC_RESVSP64;
 
 	if (!ocfs2_writes_unwritten_extents(osb))
 		return -EOPNOTSUPP;
@@ -2005,12 +2006,15 @@ static long ocfs2_fallocate(struct inode *inode, int mode, loff_t offset,
 	if (mode & FALLOC_FL_KEEP_SIZE)
 		change_size = 0;
 
+	if (mode & FALLOC_FL_PUNCH_HOLE)
+		cmd = OCFS2_IOC_UNRESVSP64;
+
 	sr.l_whence = 0;
 	sr.l_start = (s64)offset;
 	sr.l_len = (s64)len;
 
-	return __ocfs2_change_file_space(NULL, inode, offset,
-					 OCFS2_IOC_RESVSP64, &sr, change_size);
+	return __ocfs2_change_file_space(NULL, inode, offset, cmd, &sr,
+					 change_size);
 }
 
 int ocfs2_check_range_for_refcount(struct inode *inode, loff_t pos,