[Ocfs2-devel] [PATCH 11/18] ocfs2_dlm: Dumps the mles into a debugfs file

[Joel Becker]

On Mon, Feb 25, 2008 at 12:20:55PM -0800, Sunil Mushran wrote:
> This patch dumps all mles it can fit in one page into a debugfs file.
> Useful for debugging.
> 
> Signed-off-by: Sunil Mushran <sunil.mushran at oracle.com>

	Looks good modulo DEBUG_FS.

Joel

> ---
>  fs/ocfs2/dlm/dlmdebug.c |  119 +++++++++++++++++++++++++++++++++++++++++++++++
>  fs/ocfs2/dlm/dlmdebug.h |    1 +
>  2 files changed, 120 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
> index 905145a..158b2e5 100644
> --- a/fs/ocfs2/dlm/dlmdebug.c
> +++ b/fs/ocfs2/dlm/dlmdebug.c
> @@ -706,6 +706,7 @@ EXPORT_SYMBOL_GPL(dlm_errname);
>  #define DLM_DEBUGFS_DIR				"o2dlm"
>  #define DLM_DEBUGFS_DLM_STATE			"dlm_state"
>  #define DLM_DEBUGFS_LOCKING_STATE		"locking_state"
> +#define DLM_DEBUGFS_MLE_STATE			"mle_state"
>  
>  /* NOTE: This function converts a lockname into a string. It uses knowledge
>   * of the format of the lockname that should be outside the purview of the dlm.
> @@ -827,6 +828,112 @@ static int debug_buffer_release(struct inode *inode, struct file *file)
>  }
>  /* end - util funcs */
>  
> +/* begin - debug mle funcs */
> +static int dump_mle(struct dlm_master_list_entry *mle, char *buf, int len)
> +{
> +	int out = 0;
> +	unsigned int namelen;
> +	const char *name;
> +	char *mle_type;
> +
> +	if (mle->type != DLM_MLE_MASTER) {
> +		namelen = mle->u.name.len;
> +		name = mle->u.name.name;
> +	} else {
> +		namelen = mle->u.res->lockname.len;
> +		name = mle->u.res->lockname.name;
> +	}
> +
> +	if (mle->type == DLM_MLE_BLOCK)
> +		mle_type = "BLK";
> +	else if (mle->type == DLM_MLE_MASTER)
> +		mle_type = "MAS";
> +	else
> +		mle_type = "MIG";
> +
> +	out += stringify_lockname(name, namelen, buf + out, len - out);
> +	out += snprintf(buf + out, len - out,
> +			"\t%3s\tmas=%3u\tnew=%3u\tevt=%1d\tuse=%1d\tref=%3d\n",
> +			mle_type, mle->master, mle->new_master,
> +			!list_empty(&mle->hb_events),
> +			!!mle->inuse,
> +			atomic_read(&mle->mle_refs.refcount));
> +
> +	out += snprintf(buf + out, len - out, "Maybe=");
> +	out += stringify_nodemap(mle->maybe_map, O2NM_MAX_NODES,
> +				 buf + out, len - out);
> +	out += snprintf(buf + out, len - out, "\n");
> +
> +	out += snprintf(buf + out, len - out, "Vote=");
> +	out += stringify_nodemap(mle->vote_map, O2NM_MAX_NODES,
> +				 buf + out, len - out);
> +	out += snprintf(buf + out, len - out, "\n");
> +
> +	out += snprintf(buf + out, len - out, "Response=");
> +	out += stringify_nodemap(mle->response_map, O2NM_MAX_NODES,
> +				 buf + out, len - out);
> +	out += snprintf(buf + out, len - out, "\n");
> +
> +	out += snprintf(buf + out, len - out, "Node=");
> +	out += stringify_nodemap(mle->node_map, O2NM_MAX_NODES,
> +				 buf + out, len - out);
> +	out += snprintf(buf + out, len - out, "\n");
> +
> +	out += snprintf(buf + out, len - out, "\n");
> +
> +	return out;
> +}
> +
> +static int debug_mle_print(struct dlm_ctxt *dlm, struct debug_buffer *db)
> +{
> +	struct dlm_master_list_entry *mle;
> +	int out = 0;
> +	unsigned long total = 0;
> +
> +	out += snprintf(db->buf + out, db->len - out,
> +			"Dumping MLEs for Domain: %s\n", dlm->name);
> +
> +	spin_lock(&dlm->master_lock);
> +	list_for_each_entry(mle, &dlm->master_list, list) {
> +		++total;
> +		if (db->len - out < 200)
> +			continue;
> +		out += dump_mle(mle, db->buf + out, db->len - out);
> +	}
> +	spin_unlock(&dlm->master_lock);
> +
> +	out += snprintf(db->buf + out, db->len - out,
> +			"Total on list: %ld\n", total);
> +	return out;
> +}
> +
> +static int debug_mle_open(struct inode *inode, struct file *file)
> +{
> +	struct dlm_ctxt *dlm = inode->i_private;
> +	struct debug_buffer *db;
> +
> +	db = debug_buffer_allocate();
> +	if (!db)
> +		goto bail;
> +
> +	db->len = debug_mle_print(dlm, db);
> +
> +	file->private_data = db;
> +
> +	return 0;
> +bail:
> +	return -ENOMEM;
> +}
> +
> +static struct file_operations debug_mle_fops = {
> +	.open =		debug_mle_open,
> +	.release =	debug_buffer_release,
> +	.read =		debug_buffer_read,
> +	.llseek =	debug_buffer_llseek,
> +};
> +
> +/* end - debug mle funcs */
> +
>  /* begin - debug lockres funcs */
>  static int dump_lock(struct dlm_lock *lock, int list_type, char *buf, int len)
>  {
> @@ -1222,6 +1329,16 @@ int dlm_debug_init(struct dlm_ctxt *dlm)
>  		goto bail;
>  	}
>  
> +	/* for dumping mles */
> +	dc->debug_mle_dentry = debugfs_create_file(DLM_DEBUGFS_MLE_STATE,
> +						   S_IFREG|S_IRUSR,
> +						   dlm->dlm_debugfs_subroot,
> +						   dlm, &debug_mle_fops);
> +	if (!dc->debug_mle_dentry) {
> +		mlog_errno(-ENOMEM);
> +		goto bail;
> +	}
> +
>  	dlm_debug_get(dc);
>  	return 0;
>  
> @@ -1235,6 +1352,8 @@ void dlm_debug_shutdown(struct dlm_ctxt *dlm)
>  	struct dlm_debug_ctxt *dc = dlm->dlm_debug_ctxt;
>  
>  	if (dc) {
> +		if (dc->debug_mle_dentry)
> +			debugfs_remove(dc->debug_mle_dentry);
>  		if (dc->debug_lockres_dentry)
>  			debugfs_remove(dc->debug_lockres_dentry);
>  		if (dc->debug_state_dentry)
> diff --git a/fs/ocfs2/dlm/dlmdebug.h b/fs/ocfs2/dlm/dlmdebug.h
> index 86d02f4..c6b240f 100644
> --- a/fs/ocfs2/dlm/dlmdebug.h
> +++ b/fs/ocfs2/dlm/dlmdebug.h
> @@ -29,6 +29,7 @@ struct dlm_debug_ctxt {
>  	struct kref debug_refcnt;
>  	struct dentry *debug_state_dentry;
>  	struct dentry *debug_lockres_dentry;
> +	struct dentry *debug_mle_dentry;
>  };
>  
>  struct debug_buffer
> -- 
> 1.5.2.5
> 
> 
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> Ocfs2-devel at oss.oracle.com
> http://oss.oracle.com/mailman/listinfo/ocfs2-devel

-- 

Bram's Law:
	The easier a piece of software is to write, the worse it's
	implemented in practice.

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127