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nbd: Add debugfs entries

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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: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Markus Pargmann 2015-08-17 08:20:06 +02:00 committed by Jens Axboe
parent 6521d39a64
commit 30d53d9c11
1 changed files with 177 additions and 1 deletions
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178
drivers/block/nbd.c
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@ -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;