Commit 30d53d9c authored by Markus Pargmann's avatar Markus Pargmann Committed by Jens Axboe
Browse files

nbd: Add debugfs entries 



Add some debugfs files that help to understand the internal state of
NBD. This exports the different sizes, flags, tasks and so on.

Signed-off-by: default avatarMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 6521d39a

drivers/block/nbd.c

+177 −1
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#include <linux/net.h>

#include <linux/kthread.h>

#include <linux/types.h>

#include <linux/debugfs.h>



#include <asm/uaccess.h>

#include <asm/types.h>
@@ -61,8 +62,18 @@ struct nbd_device { 
	struct timer_list timeout_timer;

	struct task_struct *task_recv;

	struct task_struct *task_send;



#if IS_ENABLED(CONFIG_DEBUG_FS)

	struct dentry *dbg_dir;

#endif

};



#if IS_ENABLED(CONFIG_DEBUG_FS)

static struct dentry *nbd_dbg_dir;

#endif



#define nbd_name(nbd) ((nbd)->disk->disk_name)



#define NBD_MAGIC 0x68797548



static unsigned int nbds_max = 16;
@@ -609,6 +620,9 @@ static void do_nbd_request(struct request_queue *q) 
	}

}



static int nbd_dev_dbg_init(struct nbd_device *nbd);

static void nbd_dev_dbg_close(struct nbd_device *nbd);



/* Must be called with tx_lock held */



static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
@@ -725,13 +739,15 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, 
			blk_queue_flush(nbd->disk->queue, 0);



		thread = kthread_run(nbd_thread, nbd, "%s",

				     nbd->disk->disk_name);

				     nbd_name(nbd));

		if (IS_ERR(thread)) {

			mutex_lock(&nbd->tx_lock);

			return PTR_ERR(thread);

		}



		nbd_dev_dbg_init(nbd);

		error = nbd_do_it(nbd);

		nbd_dev_dbg_close(nbd);

		kthread_stop(thread);



		mutex_lock(&nbd->tx_lock);
@@ -797,6 +813,161 @@ static const struct block_device_operations nbd_fops = 
	.ioctl =	nbd_ioctl,

};



#if IS_ENABLED(CONFIG_DEBUG_FS)



static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)

{

	struct nbd_device *nbd = s->private;



	if (nbd->task_recv)

		seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));

	if (nbd->task_send)

		seq_printf(s, "send: %d\n", task_pid_nr(nbd->task_send));



	return 0;

}



static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)

{

	return single_open(file, nbd_dbg_tasks_show, inode->i_private);

}



static const struct file_operations nbd_dbg_tasks_ops = {

	.open = nbd_dbg_tasks_open,

	.read = seq_read,

	.llseek = seq_lseek,

	.release = single_release,

};



static int nbd_dbg_flags_show(struct seq_file *s, void *unused)

{

	struct nbd_device *nbd = s->private;

	u32 flags = nbd->flags;



	seq_printf(s, "Hex: 0x%08x\n\n", flags);



	seq_puts(s, "Known flags:\n");



	if (flags & NBD_FLAG_HAS_FLAGS)

		seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");

	if (flags & NBD_FLAG_READ_ONLY)

		seq_puts(s, "NBD_FLAG_READ_ONLY\n");

	if (flags & NBD_FLAG_SEND_FLUSH)

		seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");

	if (flags & NBD_FLAG_SEND_TRIM)

		seq_puts(s, "NBD_FLAG_SEND_TRIM\n");



	return 0;

}



static int nbd_dbg_flags_open(struct inode *inode, struct file *file)

{

	return single_open(file, nbd_dbg_flags_show, inode->i_private);

}



static const struct file_operations nbd_dbg_flags_ops = {

	.open = nbd_dbg_flags_open,

	.read = seq_read,

	.llseek = seq_lseek,

	.release = single_release,

};



static int nbd_dev_dbg_init(struct nbd_device *nbd)

{

	struct dentry *dir;

	struct dentry *f;



	dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);

	if (IS_ERR_OR_NULL(dir)) {

		dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s' (%ld)\n",

			nbd_name(nbd), PTR_ERR(dir));

		return PTR_ERR(dir);

	}

	nbd->dbg_dir = dir;



	f = debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);

	if (IS_ERR_OR_NULL(f)) {

		dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'tasks', %ld\n",

			PTR_ERR(f));

		return PTR_ERR(f);

	}



	f = debugfs_create_u64("size_bytes", 0444, dir, &nbd->bytesize);

	if (IS_ERR_OR_NULL(f)) {

		dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'size_bytes', %ld\n",

			PTR_ERR(f));

		return PTR_ERR(f);

	}



	f = debugfs_create_u32("timeout", 0444, dir, &nbd->xmit_timeout);

	if (IS_ERR_OR_NULL(f)) {

		dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'timeout', %ld\n",

			PTR_ERR(f));

		return PTR_ERR(f);

	}



	f = debugfs_create_u32("blocksize", 0444, dir, &nbd->blksize);

	if (IS_ERR_OR_NULL(f)) {

		dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'blocksize', %ld\n",

			PTR_ERR(f));

		return PTR_ERR(f);

	}



	f = debugfs_create_file("flags", 0444, dir, &nbd, &nbd_dbg_flags_ops);

	if (IS_ERR_OR_NULL(f)) {

		dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'flags', %ld\n",

			PTR_ERR(f));

		return PTR_ERR(f);

	}



	return 0;

}



static void nbd_dev_dbg_close(struct nbd_device *nbd)

{

	debugfs_remove_recursive(nbd->dbg_dir);

}



static int nbd_dbg_init(void)

{

	struct dentry *dbg_dir;



	dbg_dir = debugfs_create_dir("nbd", NULL);

	if (IS_ERR(dbg_dir))

		return PTR_ERR(dbg_dir);



	nbd_dbg_dir = dbg_dir;



	return 0;

}



static void nbd_dbg_close(void)

{

	debugfs_remove_recursive(nbd_dbg_dir);

}



#else  /* IS_ENABLED(CONFIG_DEBUG_FS) */



static int nbd_dev_dbg_init(struct nbd_device *nbd)

{

	return 0;

}



static void nbd_dev_dbg_close(struct nbd_device *nbd)

{

}



static int nbd_dbg_init(void)

{

	return 0;

}



static void nbd_dbg_close(void)

{

}



#endif



/*

 * And here should be modules and kernel interface 

 *  (Just smiley confuses emacs :-)
@@ -874,6 +1045,8 @@ static int __init nbd_init(void) 


	printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);



	nbd_dbg_init();



	for (i = 0; i < nbds_max; i++) {

		struct gendisk *disk = nbd_dev[i].disk;

		nbd_dev[i].magic = NBD_MAGIC;
@@ -910,6 +1083,9 @@ static int __init nbd_init(void) 
static void __exit nbd_cleanup(void)

{

	int i;



	nbd_dbg_close();



	for (i = 0; i < nbds_max; i++) {

		struct gendisk *disk = nbd_dev[i].disk;

		nbd_dev[i].magic = 0;