From: Pekka Enberg <penberg@cs.helsinki.fi>
Date: Thu, 7 Dec 2006 04:35:29 +0000 (-0800)
Subject: [PATCH] ext4: fsid for statvfs
X-Git-Tag: v2.6.20-rc1~145^2^2~235
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=960cc398a7a2acfe455b2ec33c64dc6018c83aab;p=linux-2.6-omap-h63xx.git

[PATCH] ext4: fsid for statvfs

Update ext4_statfs to return an FSID that is a 64 bit XOR of the 128 bit
filesystem UUID as suggested by Andreas Dilger.  See the following Bugzilla
entry for details:

  http://bugzilla.kernel.org/show_bug.cgi?id=136

Cc: Andreas Dilger <adilger@clusterfs.com>
Cc: Stephen Tweedie <sct@redhat.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f2e8c4aa0fd..2ede7e2c701 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2460,6 +2460,7 @@ static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf)
 	struct ext4_super_block *es = sbi->s_es;
 	ext4_fsblk_t overhead;
 	int i;
+	u64 fsid;
 
 	if (test_opt (sb, MINIX_DF))
 		overhead = 0;
@@ -2506,6 +2507,10 @@ static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf)
 	buf->f_files = le32_to_cpu(es->s_inodes_count);
 	buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter);
 	buf->f_namelen = EXT4_NAME_LEN;
+	fsid = le64_to_cpup((void *)es->s_uuid) ^
+	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
+	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
+	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
 	return 0;
 }