On Mon, 12 Jul 2010 12:05:43 +0530, "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> wrote:
> 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@xxxxxxxxxxxxxxxxxx>
> ---
> fs/namespace.c | 3 +++
> include/linux/fs.h | 1 +
> 2 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 88058de..5dbdbd6 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -871,6 +871,9 @@ static int show_mountinfo(struct seq_file *m, void *v)
> if (IS_MNT_UNBINDABLE(mnt))
> seq_puts(m, " unbindable");
>
> + /* 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 3103c39..5f43472 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1367,6 +1367,7 @@ 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;
since it is an optional tag is it ok to do the below patch ? or does
optional is a way to introduce changes across kernel version and
each line is suppose to have new added fields ?. Is there a userspace
tool that use /proc/<pid>/mouninfo ?
diff --git a/fs/namespace.c b/fs/namespace.c
index 5dbdbd6..7542959 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -833,6 +833,16 @@ 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; /* not nil */
+ return 1; /* is nil */
+}
+
static int show_mountinfo(struct seq_file *m, void *v)
{
struct proc_mounts *p = m->private;
@@ -871,8 +881,9 @@ 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);
+ seq_printf(m, " uuid:%pU", mnt->mnt_sb->s_uuid);
/* Filesystem specific data */
seq_puts(m, " - ");
--
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