[PATCH -V7 6/9] ext4: Add get_fsid callback

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/ext4/super.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e14d22c..fc7d464 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1049,6 +1049,19 @@ static int bdev_try_to_free_page(struct super_block *sb, struct page *page,
 	return try_to_free_buffers(page);
 }
 
+static int ext4_get_fsid(struct super_block *sb, struct uuid *fsid)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+
+	memcpy(fsid->uuid, es->s_uuid, sizeof(fsid->uuid));
+	/*
+	 * We may want to make sure we return error if the s_uuid is not
+	 * exactly unique
+	 */
+	return 0;
+}
+
 #ifdef CONFIG_QUOTA
 #define QTYPE2NAME(t) ((t) == USRQUOTA ? "user" : "group")
 #define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
@@ -1109,6 +1122,7 @@ static const struct super_operations ext4_sops = {
 	.quota_write	= ext4_quota_write,
 #endif
 	.bdev_try_to_free_page = bdev_try_to_free_page,
+	.get_fsid	= ext4_get_fsid,
 };
 
 static const struct super_operations ext4_nojournal_sops = {
@@ -1128,6 +1142,7 @@ static const struct super_operations ext4_nojournal_sops = {
 	.quota_write	= ext4_quota_write,
 #endif
 	.bdev_try_to_free_page = bdev_try_to_free_page,
+	.get_fsid	= ext4_get_fsid,
 };
 
 static const struct export_operations ext4_export_ops = {
-- 
1.7.1.78.g212f0