[PATCH -V18 11/13] vfs: Export file system uuid via /proc//mountinfo

Aneesh Kumar K.V
2010-08-20T01:52:36Z

We add a per superblock uuid field. File systems should
update the uuid in the fill_super callback

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
fs/namespace.c | 16 ++++++++++++++++
include/linux/fs.h | 1 +
2 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 2e10cb1..041645a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -837,6 +837,18 @@ const struct seq_operations mounts_op = {
.show = show_vfsmnt
};

+static int uuid_is_nil(u8 *uuid)
+{
+ int i;
+ u8 *cp = (u8 *)uuid;
+
+ for (i = 0; i < 16; i++) {
+ if (*cp++)
+ return 0;
+ }
+ return 1;
+}
+
static int show_mountinfo(struct seq_file *m, void *v)
{
struct proc_mounts *p = m->private;
@@ -875,6 +887,10 @@ static int show_mountinfo(struct seq_file *m, void *v)
if (IS_MNT_UNBINDABLE(mnt))
seq_puts(m, " unbindable");

+ if (!uuid_is_nil(mnt->mnt_sb->s_uuid))
+ /* print the uuid */
+ seq_printf(m, " uuid:%pU", mnt->mnt_sb->s_uuid);
+
/* Filesystem specific data */
seq_puts(m, " - ");
show_type(m, sb);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3eb3571..06654e5 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1370,6 +1370,7 @@ struct super_block {
wait_queue_head_t s_wait_unfrozen;

char s_id[32]; /* Informational name */
+ u8 s_uuid[16]; /* UUID */

void *s_fs_info; /* Filesystem private info */
fmode_t s_mode;
--
1.7.0.4