[Ocfs2-devel] [PATCH 3/9] ocfs2: Exposes the file system state via debugfs

[Mark Fasheh <mfasheh@suse.com>]

On Tue, Dec 16, 2008 at 03:49:17PM -0800, Sunil Mushran wrote:
> Patch creates a per mount debugfs file, fs_state, which exposes information
> like, cluster stack in use, states of the downconvert, recovery and commit
> threads, number of journal txns, some allocation stats, list of all slots, etc.
> 
> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
> ---
>  fs/ocfs2/ocfs2.h |    1 +
>  fs/ocfs2/super.c |  220 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 221 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
> index 3fed9e3..d912b70 100644
> --- a/fs/ocfs2/ocfs2.h
> +++ b/fs/ocfs2/ocfs2.h
> @@ -301,6 +301,7 @@ struct ocfs2_super
>  	struct ocfs2_dlm_debug *osb_dlm_debug;
>  
>  	struct dentry *osb_debug_root;
> +	struct dentry *osb_ctxt;
>  
>  	wait_queue_head_t recovery_event;
>  
> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
> index 304b63a..7808866 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -619,6 +619,214 @@ static int ocfs2_verify_userspace_stack(struct ocfs2_super *osb,
>  	return 0;
>  }
>  
> +#ifdef CONFIG_DEBUG_FS
> +struct ocfs2_debug_buffer {
> +	int len;
> +	char *buf;
> +};
> +
> +static int ocfs2_osb_dump(struct ocfs2_super *osb, char *buf, int len)
> +{
> +	int out = 0;
> +	int i;
> +	struct ocfs2_cluster_connection *cconn = osb->cconn;
> +	struct ocfs2_recovery_map *rm = osb->recovery_map;
> +
> +	out += snprintf(buf + out, len - out,
> +			"%10s => Id: %-s  Uuid: %-s  Gen: 0x%X  Label: %-s\n",
> +			"Device", osb->dev_str, osb->uuid_str,
> +			osb->fs_generation, osb->vol_label);
> +
> +	out += snprintf(buf + out, len - out,
> +			"%10s => State: %d  Flags: 0x%lX\n", "Volume",
> +			atomic_read(&osb->vol_state), osb->osb_flags);
> +
> +	out += snprintf(buf + out, len - out,
> +			"%10s => Block: %lu  Cluster: %d\n", "Sizes",
> +			osb->sb->s_blocksize, osb->s_clustersize);
> +
> +	out += snprintf(buf + out, len - out,
> +			"%10s => Compat: 0x%X  Incompat: 0x%X  "
> +			"ROcompat: 0x%X\n",
> +			"Features", osb->s_feature_compat,
> +			osb->s_feature_incompat, osb->s_feature_ro_compat);
> +
> +	out += snprintf(buf + out, len - out,
> +			"%10s => Opts: 0x%lX  AtimeQuanta: %u\n", "Mount",
> +			osb->s_mount_opt, osb->s_atime_quantum);

A lot of the above seems a bit like overkill to me. Couldn't we just get
this stuff with 'mount' and 'debugfs.ocfs2'?



> +	out += snprintf(buf + out, len - out,
> +			"%10s => Stack: %s  Name: %*s  Version: %d.%d\n",
> +			"Cluster",
> +			(*osb->osb_cluster_stack == '\0' ?
> +			 "o2cb" : osb->osb_cluster_stack),
> +			cconn->cc_namelen, cconn->cc_name,
> +			cconn->cc_version.pv_major, cconn->cc_version.pv_minor);
> +
> +	spin_lock(&osb->dc_task_lock);
> +	out += snprintf(buf + out, len - out,
> +			"%10s => Pid: %d  Count: %lu  WakeSeq: %lu  "
> +			"WorkSeq: %lu\n", "DownCnvt",
> +			task_pid_nr(osb->dc_task), osb->blocked_lock_count,
> +			osb->dc_wake_sequence, osb->dc_work_sequence);
> +	spin_unlock(&osb->dc_task_lock);
> +
> +	spin_lock(&osb->osb_lock);
> +	out += snprintf(buf + out, len - out, "%10s => Pid: %d  Nodes:",
> +			"Recovery",
> +			(osb->recovery_thread_task ?
> +			 task_pid_nr(osb->recovery_thread_task) : -1));
> +	if (rm->rm_used == 0)
> +		out += snprintf(buf + out, len - out, " None\n");
> +	else {
> +		for (i = 0; i < rm->rm_used; i++)
> +			out += snprintf(buf + out, len - out, " %d",
> +					rm->rm_entries[i]);
> +		out += snprintf(buf + out, len - out, "\n");
> +	}
> +	spin_unlock(&osb->osb_lock);
> +
> +	out += snprintf(buf + out, len - out,
> +			"%10s => Pid: %d  Interval: %lu  Needs: %d\n", "Commit",
> +			task_pid_nr(osb->commit_task), osb->osb_commit_interval,
> +			atomic_read(&osb->needs_checkpoint));
> +
> +	out += snprintf(buf + out, len - out,
> +			"%10s => State: %d  NumTxns: %d  TxnId: %lu\n",
> +			"Journal", osb->journal->j_state,
> +			atomic_read(&osb->journal->j_num_trans),
> +			osb->journal->j_trans_id);
> +
> +	out += snprintf(buf + out, len - out,
> +			"%10s => GlobalAllocs: %d  LocalAllocs: %d  "
> +			"SubAllocs: %d  LAWinMoves: %d  SAExtends: %d\n",
> +			"Stats",
> +			atomic_read(&osb->alloc_stats.bitmap_data),
> +			atomic_read(&osb->alloc_stats.local_data),
> +			atomic_read(&osb->alloc_stats.bg_allocs),
> +			atomic_read(&osb->alloc_stats.moves),
> +			atomic_read(&osb->alloc_stats.bg_extends));
> +
> +	out += snprintf(buf + out, len - out,
> +			"%10s => State: %u  Descriptor: %llu  Size: %u bits  "
> +			"Default: %u bits\n",
> +			"LocalAlloc", osb->local_alloc_state,
> +			(unsigned long long)osb->la_last_gd,
> +			osb->local_alloc_bits, osb->local_alloc_default_bits);
> +
> +	spin_lock(&osb->osb_lock);
> +	out += snprintf(buf + out, len - out,
> +			"%10s => Slot: %d  NumStolen: %d\n", "Steal",
> +			osb->s_inode_steal_slot,
> +			atomic_read(&osb->s_num_inodes_stolen));
> +	spin_unlock(&osb->osb_lock);
> +
> +	out += snprintf(buf + out, len - out, "%10s => %3s  %10s\n",
> +			"Slots", "Num", "RecoGen");
> +
> +	for (i = 0; i < osb->max_slots; ++i) {
> +		out += snprintf(buf + out, len - out,
> +				"%10s  %c %3d  %10d\n",
> +				" ",
> +				(i == osb->slot_num ? '*' : ' '),
> +				i, osb->slot_recovery_generations[i]);
> +	}

Also, I wonder if it's not a bad idea to split out the important stuff into
their own files.


> +
> +	return out;
> +}
> +
> +static int ocfs2_osb_debug_open(struct inode *inode, struct file *file)
> +{
> +	struct ocfs2_debug_buffer *odb = NULL;
> +	struct ocfs2_super *osb = inode->i_private;
> +
> +	odb = kzalloc(sizeof(struct ocfs2_debug_buffer), GFP_KERNEL);
> +	if (!odb)
> +		goto bail;
> +
> +	odb->len = PAGE_SIZE;
> +	odb->buf = kmalloc(odb->len, GFP_KERNEL);
> +	if (!odb->buf) {
> +		kfree(odb);
> +		goto bail;
> +	}
> +
> +	odb->len = ocfs2_osb_dump(osb, odb->buf, odb->len);
> +
> +	file->private_data = odb;
> +
> +	return 0;
> +bail:
> +	return -ENOMEM;
> +}
> +
> +static int ocfs2_debug_release(struct inode *inode, struct file *file)
> +{
> +	struct ocfs2_debug_buffer *odb =
> +			(struct ocfs2_debug_buffer *)file->private_data;
> +
> +	kfree(odb->buf);
> +	kfree(odb);
> +
> +	return 0;
> +}
> +
> +static ssize_t ocfs2_debug_read(struct file *file, char __user *buf,
> +				size_t nbytes, loff_t *ppos)
> +{
> +	struct ocfs2_debug_buffer *odb =
> +			(struct ocfs2_debug_buffer *)file->private_data;
> +
> +	return simple_read_from_buffer(buf, nbytes, ppos, odb->buf, odb->len);
> +}
> +
> +static loff_t ocfs2_debug_llseek(struct file *file, loff_t off, int whence)
> +{
> +	struct ocfs2_debug_buffer *odb =
> +			(struct ocfs2_debug_buffer *)file->private_data;
> +	loff_t new = -1;
> +
> +	switch (whence) {
> +	case 0:
> +		new = off;
> +		break;
> +	case 1:
> +		new = file->f_pos + off;
> +		break;
> +	}
> +
> +	if (new < 0 || new > odb->len)
> +		return -EINVAL;
> +
> +	return (file->f_pos = new);
> +}

Same comment regarding generic_file_llseek() here.
	--Mark

--
Mark Fasheh