Re: [Ocfs2-devel] [PATCH v2 1/2] ocfs2: add trimfs dlm lock resource

[Changwei Ge]

Hi Gang,

On 2017/12/14 13:16, Gang He wrote:
> Introduce a new dlm lock resource, which will be used to
> communicate during fstrim a ocfs2 device from cluster nodes.
> 
> Signed-off-by: Gang He <ghe@xxxxxxxx>
> ---
>   fs/ocfs2/dlmglue.c      | 86 +++++++++++++++++++++++++++++++++++++++++++++++++
>   fs/ocfs2/dlmglue.h      | 29 +++++++++++++++++
>   fs/ocfs2/ocfs2.h        |  1 +
>   fs/ocfs2/ocfs2_lockid.h |  5 +++
>   4 files changed, 121 insertions(+)
> 
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index 4689940..5615747 100644
> --- a/fs/ocfs2/dlmglue.c
> +++ b/fs/ocfs2/dlmglue.c
> @@ -259,6 +259,10 @@ struct ocfs2_lock_res_ops {
>   	.flags		= 0,
>   };
>   
> +static struct ocfs2_lock_res_ops ocfs2_trim_fs_lops = {
> +	.flags		= LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,

Um, I don't think it is proper to add flag LOCK_TYPE_REQUIRES_REFRESH.
Because it seems that trimfs procedure doesn't have to persist stuff into disk.

Thanks,
Changwei

> +};
> +
>   static struct ocfs2_lock_res_ops ocfs2_orphan_scan_lops = {
>   	.flags		= LOCK_TYPE_REQUIRES_REFRESH|LOCK_TYPE_USES_LVB,
>   };
> @@ -676,6 +680,24 @@ static void ocfs2_nfs_sync_lock_res_init(struct ocfs2_lock_res *res,
>   				   &ocfs2_nfs_sync_lops, osb);
>   }
>   
> +void ocfs2_trim_fs_lock_res_init(struct ocfs2_super *osb)
> +{
> +	struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
> +
> +	ocfs2_lock_res_init_once(lockres);
> +	ocfs2_build_lock_name(OCFS2_LOCK_TYPE_TRIM_FS, 0, 0, lockres->l_name);
> +	ocfs2_lock_res_init_common(osb, lockres, OCFS2_LOCK_TYPE_TRIM_FS,
> +				   &ocfs2_trim_fs_lops, osb);
> +}
> +
> +void ocfs2_trim_fs_lock_res_uninit(struct ocfs2_super *osb)
> +{
> +	struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
> +
> +	ocfs2_simple_drop_lockres(osb, lockres);
> +	ocfs2_lock_res_free(lockres);
> +}
> +
>   static void ocfs2_orphan_scan_lock_res_init(struct ocfs2_lock_res *res,
>   					    struct ocfs2_super *osb)
>   {
> @@ -2745,6 +2767,70 @@ void ocfs2_nfs_sync_unlock(struct ocfs2_super *osb, int ex)
>   				     ex ? LKM_EXMODE : LKM_PRMODE);
>   }
>   
> +int ocfs2_trim_fs_lock(struct ocfs2_super *osb,
> +		       struct ocfs2_trim_fs_info *info, int trylock)
> +{
> +	int status;
> +	struct ocfs2_trim_fs_lvb *lvb;
> +	struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
> +
> +	if (info)
> +		info->tf_valid = 0;
> +
> +	if (ocfs2_is_hard_readonly(osb))
> +		return -EROFS;
> +
> +	if (ocfs2_mount_local(osb))
> +		return 0;
> +
> +	status = ocfs2_cluster_lock(osb, lockres, DLM_LOCK_EX,
> +				    trylock ? DLM_LKF_NOQUEUE : 0, 0);
> +	if (status < 0) {
> +		if (status != -EAGAIN)
> +			mlog_errno(status);
> +		return status;
> +	}
> +
> +	if (info) {
> +		lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
> +		if (ocfs2_dlm_lvb_valid(&lockres->l_lksb) &&
> +		    lvb->lvb_version == OCFS2_TRIMFS_LVB_VERSION) {
> +			info->tf_valid = 1;
> +			info->tf_success = lvb->lvb_success;
> +			info->tf_nodenum = be32_to_cpu(lvb->lvb_nodenum);
> +			info->tf_start = be64_to_cpu(lvb->lvb_start);
> +			info->tf_len = be64_to_cpu(lvb->lvb_len);
> +			info->tf_minlen = be64_to_cpu(lvb->lvb_minlen);
> +			info->tf_trimlen = be64_to_cpu(lvb->lvb_trimlen);
> +		}
> +	}
> +
> +	return status;
> +}
> +
> +void ocfs2_trim_fs_unlock(struct ocfs2_super *osb,
> +			  struct ocfs2_trim_fs_info *info)
> +{
> +	struct ocfs2_trim_fs_lvb *lvb;
> +	struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
> +
> +	if (ocfs2_mount_local(osb))
> +		return;
> +
> +	if (info) {
> +		lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
> +		lvb->lvb_version = OCFS2_TRIMFS_LVB_VERSION;
> +		lvb->lvb_success = info->tf_success;
> +		lvb->lvb_nodenum = cpu_to_be32(info->tf_nodenum);
> +		lvb->lvb_start = cpu_to_be64(info->tf_start);
> +		lvb->lvb_len = cpu_to_be64(info->tf_len);
> +		lvb->lvb_minlen = cpu_to_be64(info->tf_minlen);
> +		lvb->lvb_trimlen = cpu_to_be64(info->tf_trimlen);
> +	}
> +
> +	ocfs2_cluster_unlock(osb, lockres, DLM_LOCK_EX);
> +}
> +
>   int ocfs2_dentry_lock(struct dentry *dentry, int ex)
>   {
>   	int ret;
> diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
> index a7fc18b..2253688 100644
> --- a/fs/ocfs2/dlmglue.h
> +++ b/fs/ocfs2/dlmglue.h
> @@ -70,6 +70,29 @@ struct ocfs2_orphan_scan_lvb {
>   	__be32	lvb_os_seqno;
>   };
>   
> +#define OCFS2_TRIMFS_LVB_VERSION 1
> +
> +struct ocfs2_trim_fs_lvb {
> +	__u8	lvb_version;
> +	__u8	lvb_success;
> +	__u8	lvb_reserved[2];
> +	__be32	lvb_nodenum;
> +	__be64	lvb_start;
> +	__be64	lvb_len;
> +	__be64	lvb_minlen;
> +	__be64	lvb_trimlen;
> +};
> +
> +struct ocfs2_trim_fs_info {
> +	u8	tf_valid;	/* lvb is valid, or not */
> +	u8	tf_success;	/* trim is successful, or not */
> +	u32	tf_nodenum;	/* osb node number */
> +	u64	tf_start;	/* trim start offset in clusters */
> +	u64	tf_len;		/* trim end offset in clusters */
> +	u64	tf_minlen;	/* trim minimum contiguous free clusters */
> +	u64	tf_trimlen;	/* trimmed length in bytes */
> +};
> +
>   struct ocfs2_lock_holder {
>   	struct list_head oh_list;
>   	struct pid *oh_owner_pid;
> @@ -153,6 +176,12 @@ void ocfs2_super_unlock(struct ocfs2_super *osb,
>   void ocfs2_rename_unlock(struct ocfs2_super *osb);
>   int ocfs2_nfs_sync_lock(struct ocfs2_super *osb, int ex);
>   void ocfs2_nfs_sync_unlock(struct ocfs2_super *osb, int ex);
> +void ocfs2_trim_fs_lock_res_init(struct ocfs2_super *osb);
> +void ocfs2_trim_fs_lock_res_uninit(struct ocfs2_super *osb);
> +int ocfs2_trim_fs_lock(struct ocfs2_super *osb,
> +		       struct ocfs2_trim_fs_info *info, int trylock);
> +void ocfs2_trim_fs_unlock(struct ocfs2_super *osb,
> +			  struct ocfs2_trim_fs_info *info);
>   int ocfs2_dentry_lock(struct dentry *dentry, int ex);
>   void ocfs2_dentry_unlock(struct dentry *dentry, int ex);
>   int ocfs2_file_lock(struct file *file, int ex, int trylock);
> diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
> index 9a50f22..6867eef 100644
> --- a/fs/ocfs2/ocfs2.h
> +++ b/fs/ocfs2/ocfs2.h
> @@ -404,6 +404,7 @@ struct ocfs2_super
>   	struct ocfs2_lock_res osb_super_lockres;
>   	struct ocfs2_lock_res osb_rename_lockres;
>   	struct ocfs2_lock_res osb_nfs_sync_lockres;
> +	struct ocfs2_lock_res osb_trim_fs_lockres;
>   	struct ocfs2_dlm_debug *osb_dlm_debug;
>   
>   	struct dentry *osb_debug_root;
> diff --git a/fs/ocfs2/ocfs2_lockid.h b/fs/ocfs2/ocfs2_lockid.h
> index d277aab..7051b99 100644
> --- a/fs/ocfs2/ocfs2_lockid.h
> +++ b/fs/ocfs2/ocfs2_lockid.h
> @@ -50,6 +50,7 @@ enum ocfs2_lock_type {
>   	OCFS2_LOCK_TYPE_NFS_SYNC,
>   	OCFS2_LOCK_TYPE_ORPHAN_SCAN,
>   	OCFS2_LOCK_TYPE_REFCOUNT,
> +	OCFS2_LOCK_TYPE_TRIM_FS,
>   	OCFS2_NUM_LOCK_TYPES
>   };
>   
> @@ -93,6 +94,9 @@ static inline char ocfs2_lock_type_char(enum ocfs2_lock_type type)
>   		case OCFS2_LOCK_TYPE_REFCOUNT:
>   			c = 'T';
>   			break;
> +		case OCFS2_LOCK_TYPE_TRIM_FS:
> +			c = 'I';
> +			break;
>   		default:
>   			c = '\0';
>   	}
> @@ -115,6 +119,7 @@ static inline char ocfs2_lock_type_char(enum ocfs2_lock_type type)
>   	[OCFS2_LOCK_TYPE_NFS_SYNC] = "NFSSync",
>   	[OCFS2_LOCK_TYPE_ORPHAN_SCAN] = "OrphanScan",
>   	[OCFS2_LOCK_TYPE_REFCOUNT] = "Refcount",
> +	[OCFS2_LOCK_TYPE_TRIM_FS] = "TrimFs",
>   };
>   
>   static inline const char *ocfs2_lock_type_string(enum ocfs2_lock_type type)
>