[Ocfs2-devel] [PATCH 02/22] ocfs2: Add an incompat feature flag OCFS2_FEATURE_INCOMPAT_CLUSTERINFO

[Mark Fasheh]

On Thu, Oct 07, 2010 at 05:15:16PM -0700, Sunil Mushran wrote:
> OCFS2_FEATURE_INCOMPAT_CLUSTERINFO allows us to use sb->s_cluster_info for
> both userspace and o2cb cluster stacks. It also allows us to extend cluster
> info to include stack flags.
> 
> This patch also adds stackflags to sb->s_clusterinfo. It also introduces a
> clusterinfo flag OCFS2_CLUSTER_O2CB_GLOBAL_HEARTBEAT to denote the enabled
> global heartbeat mode.
> 
> This incompat flag can be set/cleared using tunefs.ocfs2 --fs-features. The
> clusterinfo flag is set/cleared using tunefs.ocfs2 --update-cluster-stack.
> 
> Signed-off-by: Sunil Mushran <sunil.mushran at oracle.com>
> ---
>  fs/ocfs2/ocfs2.h    |   31 +++++++++++++++++++++++++++++--
>  fs/ocfs2/ocfs2_fs.h |   40 ++++++++++++++++++++++++++++++++++------
>  fs/ocfs2/super.c    |    4 +++-
>  3 files changed, 66 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
> index c67003b..d5496a7 100644
> --- a/fs/ocfs2/ocfs2.h
> +++ b/fs/ocfs2/ocfs2.h
> @@ -368,6 +368,8 @@ struct ocfs2_super
>  	struct ocfs2_alloc_stats alloc_stats;
>  	char dev_str[20];		/* "major,minor" of the device */
>  
> +	u8 osb_stackflags;
> +
>  	char osb_cluster_stack[OCFS2_STACK_LABEL_LEN + 1];
>  	struct ocfs2_cluster_connection *cconn;
>  	struct ocfs2_lock_res osb_super_lockres;
> @@ -601,10 +603,35 @@ static inline int ocfs2_is_soft_readonly(struct ocfs2_super *osb)
>  	return ret;
>  }
>  
> -static inline int ocfs2_userspace_stack(struct ocfs2_super *osb)
> +static inline int ocfs2_clusterinfo_valid(struct ocfs2_super *osb)
>  {
>  	return (osb->s_feature_incompat &
> -		OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK);
> +		(OCFS2_FEATURE_INCOMPAT_USERSPACE_STACK |
> +		 OCFS2_FEATURE_INCOMPAT_CLUSTERINFO));
> +}
> +
> +static inline int ocfs2_userspace_stack(struct ocfs2_super *osb)
> +{
> +	if (ocfs2_clusterinfo_valid(osb) &&
> +	    memcmp(osb->osb_cluster_stack, OCFS2_CLASSIC_CLUSTER_STACK,
> +		   OCFS2_STACK_LABEL_LEN))
> +		return 1;
> +	return 0;
> +}
> +
> +static inline int ocfs2_o2cb_stack(struct ocfs2_super *osb)
> +{
> +	if (ocfs2_clusterinfo_valid(osb) &&
> +	    !memcmp(osb->osb_cluster_stack, OCFS2_CLASSIC_CLUSTER_STACK,
> +		   OCFS2_STACK_LABEL_LEN))
> +		return 1;
> +	return 0;
> +}
> +
> +static inline int ocfs2_cluster_o2cb_global_heartbeat(struct ocfs2_super *osb)
> +{
> +	return ocfs2_o2cb_stack(osb) &&
> +		(osb->osb_stackflags & OCFS2_CLUSTER_O2CB_GLOBAL_HEARTBEAT);
>  }
>  
>  static inline int ocfs2_mount_local(struct ocfs2_super *osb)
> diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
> index fa31d05..b4ca517 100644
> --- a/fs/ocfs2/ocfs2_fs.h
> +++ b/fs/ocfs2/ocfs2_fs.h
> @@ -101,7 +101,8 @@
>  					 | OCFS2_FEATURE_INCOMPAT_META_ECC \
>  					 | OCFS2_FEATURE_INCOMPAT_INDEXED_DIRS \
>  					 | OCFS2_FEATURE_INCOMPAT_REFCOUNT_TREE \
> -					 | OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG)
> +					 | OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG	\
> +					 | OCFS2_FEATURE_INCOMPAT_CLUSTERINFO)
>  #define OCFS2_FEATURE_RO_COMPAT_SUPP	(OCFS2_FEATURE_RO_COMPAT_UNWRITTEN \
>  					 | OCFS2_FEATURE_RO_COMPAT_USRQUOTA \
>  					 | OCFS2_FEATURE_RO_COMPAT_GRPQUOTA)
> @@ -170,6 +171,13 @@
>  #define OCFS2_FEATURE_INCOMPAT_DISCONTIG_BG	0x2000
>  
>  /*
> + * Incompat bit to indicate useable clusterinfo with stackflags for all
> + * cluster stacks (userspace adnd o2cb). If this bit is set,
> + * INCOMPAT_USERSPACE_STACK becomes superfluous and thus should not be set.
> + */
> +#define OCFS2_FEATURE_INCOMPAT_CLUSTERINFO	0x4000
> +
> +/*
>   * backup superblock flag is used to indicate that this volume
>   * has backup superblocks.
>   */
> @@ -292,10 +300,13 @@
>  #define OCFS2_VOL_UUID_LEN		16
>  #define OCFS2_MAX_VOL_LABEL_LEN		64
>  
> -/* The alternate, userspace stack fields */
> +/* The cluster stack fields */
>  #define OCFS2_STACK_LABEL_LEN		4
>  #define OCFS2_CLUSTER_NAME_LEN		16
>  
> +/* Classic (historically speaking) cluster stack */
> +#define OCFS2_CLASSIC_CLUSTER_STACK	"o2cb"
> +
>  /* Journal limits (in bytes) */
>  #define OCFS2_MIN_JOURNAL_SIZE		(4 * 1024 * 1024)
>  
> @@ -305,6 +316,11 @@
>   */
>  #define OCFS2_MIN_XATTR_INLINE_SIZE     256
>  
> +/*
> + * Cluster info flags (ocfs2_cluster_info.ci_stackflags)
> + */
> +#define OCFS2_CLUSTER_O2CB_GLOBAL_HEARTBEAT	(0x01)
> +
>  struct ocfs2_system_inode_info {
>  	char	*si_name;
>  	int	si_iflags;
> @@ -566,9 +582,21 @@ struct ocfs2_slot_map_extended {
>   */
>  };
>  
> +/*
> + * ci_stackflags is only valid if the incompat bit
> + * OCFS2_FEATURE_INCOMPAT_CLUSTERINFO is set.
> + */
>  struct ocfs2_cluster_info {
>  /*00*/	__u8   ci_stack[OCFS2_STACK_LABEL_LEN];
> -	__le32 ci_reserved;
> +	union {
> +		__le32 ci_reserved;
> +		struct {
> +			__u8 ci_reserved1;
> +			__u8 ci_reserved2;
> +			__u8 ci_reserved3;
> +			__u8 ci_stackflags;

Just curious, why stick ci_stackflags at the bottom of this structure?

Wouldn't putting it at the top allow us to grow the field in the future...


Otherwise the patch looks good to me.
	--Mark

--
Mark Fasheh