jfs: return f_fsid for statfs(2)

This patch makes jfs return f_fsid info for statfs(2). By Andreas'
suggestion, this patch populates a persistent f_fsid between boots/mounts
with help of on-disk uuid record.

Signed-off-by: Coly Li <coly.li@suse.de>
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>

fs/jfs/super.c

@@ -29,6 +29,7 @@
 #include <linux/posix_acl.h>
 #include <linux/buffer_head.h>
 #include <linux/exportfs.h>
+#include <linux/crc32.h>
 #include <asm/uaccess.h>
 #include <linux/seq_file.h>
 
@@ -168,6 +169,9 @@ static int jfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_files = maxinodes;
 	buf->f_ffree = maxinodes - (atomic_read(&imap->im_numinos) -
 				    atomic_read(&imap->im_numfree));
+	buf->f_fsid.val[0] = (u32)crc32_le(0, sbi->uuid, sizeof(sbi->uuid)/2);
+	buf->f_fsid.val[1] = (u32)crc32_le(0, sbi->uuid + sizeof(sbi->uuid)/2,
+					sizeof(sbi->uuid)/2);
 
 	buf->f_namelen = JFS_NAME_MAX;
 	return 0;