bcachefs-tools/libbcache/debug.c

/*
 * Assorted bcache debug code
 *
 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
 * Copyright 2012 Google, Inc.
 */

#include "bcache.h"
#include "bkey_methods.h"
#include "btree_cache.h"
#include "btree_io.h"
#include "btree_iter.h"
#include "btree_update.h"
#include "buckets.h"
#include "debug.h"
#include "error.h"
#include "extents.h"
#include "fs-gc.h"
#include "inode.h"
#include "io.h"
#include "super.h"

#include <linux/console.h>
#include <linux/debugfs.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/seq_file.h>

static struct dentry *bch_debug;

#ifdef CONFIG_BCACHE_DEBUG

static void btree_verify_endio(struct bio *bio)
{
	struct closure *cl = bio->bi_private;

	closure_put(cl);
}

void __bch_btree_verify(struct cache_set *c, struct btree *b)
{
	struct btree *v = c->verify_data;
	struct btree_node *n_ondisk, *n_sorted, *n_inmemory;
	struct bset *sorted, *inmemory;
	struct extent_pick_ptr pick;
	struct bio *bio;
	struct closure cl;

	closure_init_stack(&cl);

	btree_node_io_lock(b);
	mutex_lock(&c->verify_lock);

	n_ondisk = c->verify_ondisk;
	n_sorted = c->verify_data->data;
	n_inmemory = b->data;

	bkey_copy(&v->key, &b->key);
	v->written	= 0;
	v->level	= b->level;
	v->btree_id	= b->btree_id;
	bch_btree_keys_init(v, &c->expensive_debug_checks);

	pick = bch_btree_pick_ptr(c, b);
	if (IS_ERR_OR_NULL(pick.ca))
		return;

	bio = bio_alloc_bioset(GFP_NOIO, btree_pages(c), &c->btree_read_bio);
	bio->bi_bdev		= pick.ca->disk_sb.bdev;
	bio->bi_iter.bi_sector	= pick.ptr.offset;
	bio->bi_iter.bi_size	= btree_bytes(c);
	bio_set_op_attrs(bio, REQ_OP_READ, REQ_META|READ_SYNC);
	bio->bi_private		= &cl;
	bio->bi_end_io		= btree_verify_endio;
	bch_bio_map(bio, n_sorted);

	closure_get(&cl);
	bch_generic_make_request(bio, c);
	closure_sync(&cl);

	bio_put(bio);

	memcpy(n_ondisk, n_sorted, btree_bytes(c));

	bch_btree_node_read_done(c, v, pick.ca, &pick.ptr);
	n_sorted = c->verify_data->data;

	percpu_ref_put(&pick.ca->ref);

	sorted = &n_sorted->keys;
	inmemory = &n_inmemory->keys;

	if (inmemory->u64s != sorted->u64s ||
	    memcmp(inmemory->start,
		   sorted->start,
		   (void *) bset_bkey_last(inmemory) - (void *) inmemory->start)) {
		unsigned offset = 0, sectors;
		struct bset *i;
		unsigned j;

		console_lock();

		printk(KERN_ERR "*** in memory:\n");
		bch_dump_bset(b, inmemory, 0);

		printk(KERN_ERR "*** read back in:\n");
		bch_dump_bset(v, sorted, 0);

		while (offset < b->written) {
			if (!offset ) {
				i = &n_ondisk->keys;
				sectors = __set_blocks(n_ondisk,
						       le16_to_cpu(n_ondisk->keys.u64s),
						       block_bytes(c)) <<
					c->block_bits;
			} else {
				struct btree_node_entry *bne =
					(void *) n_ondisk + (offset << 9);
				i = &bne->keys;

				sectors = __set_blocks(bne,
						       le16_to_cpu(bne->keys.u64s),
						       block_bytes(c)) <<
					c->block_bits;
			}

			printk(KERN_ERR "*** on disk block %u:\n", offset);
			bch_dump_bset(b, i, offset);

			offset += sectors;
		}

		printk(KERN_ERR "*** block %u/%u not written\n",
		       offset >> c->block_bits, btree_blocks(c));

		for (j = 0; j < le16_to_cpu(inmemory->u64s); j++)
			if (inmemory->_data[j] != sorted->_data[j])
				break;

		printk(KERN_ERR "b->written %u\n", b->written);

		console_unlock();
		panic("verify failed at %u\n", j);
	}

	mutex_unlock(&c->verify_lock);
	btree_node_io_unlock(b);
}

void bch_data_verify(struct cached_dev *dc, struct bio *bio)
{
	char name[BDEVNAME_SIZE];
	struct bio *check;
	struct bio_vec bv;
	struct bvec_iter iter;

	check = bio_clone(bio, GFP_NOIO);
	if (!check)
		return;
	bio_set_op_attrs(check, REQ_OP_READ, READ_SYNC);

	if (bio_alloc_pages(check, GFP_NOIO))
		goto out_put;

	submit_bio_wait(check);

	bio_for_each_segment(bv, bio, iter) {
		void *p1 = kmap_atomic(bv.bv_page);
		void *p2 = page_address(check->bi_io_vec[iter.bi_idx].bv_page);

		if (memcmp(p1 + bv.bv_offset,
			   p2 + bv.bv_offset,
			   bv.bv_len))
			panic("verify failed at dev %s sector %llu\n",
			      bdevname(dc->disk_sb.bdev, name),
			      (uint64_t) bio->bi_iter.bi_sector);

		kunmap_atomic(p1);
	}

	bio_free_pages(check);
out_put:
	bio_put(check);
}

#endif

#ifdef CONFIG_DEBUG_FS

/* XXX: cache set refcounting */

struct dump_iter {
	struct bpos		from;
	struct cache_set	*c;
	enum btree_id		id;

	char			buf[PAGE_SIZE];
	size_t			bytes;	/* what's currently in buf */

	char __user		*ubuf;	/* destination user buffer */
	size_t			size;	/* size of requested read */
	ssize_t			ret;	/* bytes read so far */
};

static int flush_buf(struct dump_iter *i)
{
	if (i->bytes) {
		size_t bytes = min(i->bytes, i->size);
		int err = copy_to_user(i->ubuf, i->buf, bytes);

		if (err)
			return err;

		i->ret	 += bytes;
		i->ubuf	 += bytes;
		i->size	 -= bytes;
		i->bytes -= bytes;
		memmove(i->buf, i->buf + bytes, i->bytes);
	}

	return 0;
}

static int bch_dump_open(struct inode *inode, struct file *file)
{
	struct btree_debug *bd = inode->i_private;
	struct dump_iter *i;

	i = kzalloc(sizeof(struct dump_iter), GFP_KERNEL);
	if (!i)
		return -ENOMEM;

	file->private_data = i;
	i->from = POS_MIN;
	i->c	= container_of(bd, struct cache_set, btree_debug[bd->id]);
	i->id	= bd->id;

	return 0;
}

static int bch_dump_release(struct inode *inode, struct file *file)
{
	kfree(file->private_data);
	return 0;
}

static ssize_t bch_read_btree(struct file *file, char __user *buf,
			      size_t size, loff_t *ppos)
{
	struct dump_iter *i = file->private_data;
	struct btree_iter iter;
	struct bkey_s_c k;
	int err;

	i->ubuf = buf;
	i->size	= size;
	i->ret	= 0;

	err = flush_buf(i);
	if (err)
		return err;

	if (!i->size)
		return i->ret;

	bch_btree_iter_init(&iter, i->c, i->id, i->from);

	while ((k = bch_btree_iter_peek(&iter)).k &&
	       !(err = btree_iter_err(k))) {
		bch_bkey_val_to_text(i->c, bkey_type(0, i->id),
				     i->buf, sizeof(i->buf), k);
		i->bytes = strlen(i->buf);
		BUG_ON(i->bytes >= PAGE_SIZE);
		i->buf[i->bytes] = '\n';
		i->bytes++;

		bch_btree_iter_advance_pos(&iter);
		i->from = iter.pos;

		err = flush_buf(i);
		if (err)
			break;

		if (!i->size)
			break;
	}
	bch_btree_iter_unlock(&iter);

	return err < 0 ? err : i->ret;
}

static const struct file_operations btree_debug_ops = {
	.owner		= THIS_MODULE,
	.open		= bch_dump_open,
	.release	= bch_dump_release,
	.read		= bch_read_btree,
};

static int print_btree_node(struct dump_iter *i, struct btree *b)
{
	const struct bkey_format *f = &b->format;
	struct bset_stats stats;

	memset(&stats, 0, sizeof(stats));

	bch_btree_keys_stats(b, &stats);

	i->bytes = scnprintf(i->buf, sizeof(i->buf),
			     "l %u %llu:%llu - %llu:%llu:\n"
			     "    format: u64s %u fields %u %u %u %u %u\n"
			     "    unpack fn len: %u\n"
			     "    bytes used %zu/%zu (%zu%% full)\n"
			     "    sib u64s: %u, %u (merge threshold %zu)\n"
			     "    nr packed keys %u\n"
			     "    nr unpacked keys %u\n"
			     "    floats %zu\n"
			     "    failed unpacked %zu\n"
			     "    failed prev %zu\n"
			     "    failed overflow %zu\n",
			     b->level,
			     b->data->min_key.inode,
			     b->data->min_key.offset,
			     b->data->max_key.inode,
			     b->data->max_key.offset,
			     f->key_u64s,
			     f->bits_per_field[0],
			     f->bits_per_field[1],
			     f->bits_per_field[2],
			     f->bits_per_field[3],
			     f->bits_per_field[4],
			     b->unpack_fn_len,
			     b->nr.live_u64s * sizeof(u64),
			     btree_bytes(i->c) - sizeof(struct btree_node),
			     b->nr.live_u64s * 100 / btree_max_u64s(i->c),
			     b->sib_u64s[0],
			     b->sib_u64s[1],
			     BTREE_FOREGROUND_MERGE_THRESHOLD(i->c),
			     b->nr.packed_keys,
			     b->nr.unpacked_keys,
			     stats.floats,
			     stats.failed_unpacked,
			     stats.failed_prev,
			     stats.failed_overflow);

	return flush_buf(i);
}

static ssize_t bch_read_btree_formats(struct file *file, char __user *buf,
				      size_t size, loff_t *ppos)
{
	struct dump_iter *i = file->private_data;
	struct btree_iter iter;
	struct btree *b;
	int err;

	i->ubuf = buf;
	i->size	= size;
	i->ret	= 0;

	err = flush_buf(i);
	if (err)
		return err;

	if (!i->size || !bkey_cmp(POS_MAX, i->from))
		return i->ret;

	for_each_btree_node(&iter, i->c, i->id, i->from, 0, b) {
		err = print_btree_node(i, b);
		if (err)
			break;

		/*
		 * can't easily correctly restart a btree node traversal across
		 * all nodes, meh
		 */
		i->from = bkey_cmp(POS_MAX, b->key.k.p)
			? bkey_successor(b->key.k.p)
			: b->key.k.p;

		if (!i->size)
			break;
	}
	bch_btree_iter_unlock(&iter);

	return err < 0 ? err : i->ret;
}

static const struct file_operations btree_format_debug_ops = {
	.owner		= THIS_MODULE,
	.open		= bch_dump_open,
	.release	= bch_dump_release,
	.read		= bch_read_btree_formats,
};

static ssize_t bch_read_bfloat_failed(struct file *file, char __user *buf,
				      size_t size, loff_t *ppos)
{
	struct dump_iter *i = file->private_data;
	struct btree_iter iter;
	struct bkey_s_c k;
	struct btree *prev_node = NULL;
	int err;

	i->ubuf = buf;
	i->size	= size;
	i->ret	= 0;

	err = flush_buf(i);
	if (err)
		return err;

	if (!i->size)
		return i->ret;

	bch_btree_iter_init(&iter, i->c, i->id, i->from);

	while ((k = bch_btree_iter_peek(&iter)).k &&
	       !(err = btree_iter_err(k))) {
		struct btree *b = iter.nodes[0];
		struct btree_node_iter *node_iter = &iter.node_iters[0];
		struct bkey_packed *_k = bch_btree_node_iter_peek(node_iter, b);

		if (iter.nodes[0] != prev_node) {
			err = print_btree_node(i, iter.nodes[0]);
			if (err)
				break;
		}
		prev_node = iter.nodes[0];

		i->bytes = bch_bkey_print_bfloat(b, _k, i->buf, sizeof(i->buf));

		err = flush_buf(i);
		if (err)
			break;

		bch_btree_iter_advance_pos(&iter);
		i->from = iter.pos;

		err = flush_buf(i);
		if (err)
			break;

		if (!i->size)
			break;
	}
	bch_btree_iter_unlock(&iter);

	return err < 0 ? err : i->ret;
}

static const struct file_operations bfloat_failed_debug_ops = {
	.owner		= THIS_MODULE,
	.open		= bch_dump_open,
	.release	= bch_dump_release,
	.read		= bch_read_bfloat_failed,
};

void bch_debug_exit_cache_set(struct cache_set *c)
{
	if (!IS_ERR_OR_NULL(c->debug))
		debugfs_remove_recursive(c->debug);
}

void bch_debug_init_cache_set(struct cache_set *c)
{
	struct btree_debug *bd;
	char name[100];

	if (IS_ERR_OR_NULL(bch_debug))
		return;

	snprintf(name, sizeof(name), "%pU", c->disk_sb.user_uuid.b);
	c->debug = debugfs_create_dir(name, bch_debug);
	if (IS_ERR_OR_NULL(c->debug))
		return;

	for (bd = c->btree_debug;
	     bd < c->btree_debug + ARRAY_SIZE(c->btree_debug);
	     bd++) {
		bd->id = bd - c->btree_debug;
		bd->btree = debugfs_create_file(bch_btree_id_names[bd->id],
						0400, c->debug, bd,
						&btree_debug_ops);

		snprintf(name, sizeof(name), "%s-formats",
			 bch_btree_id_names[bd->id]);

		bd->btree_format = debugfs_create_file(name, 0400, c->debug, bd,
						       &btree_format_debug_ops);

		snprintf(name, sizeof(name), "%s-bfloat-failed",
			 bch_btree_id_names[bd->id]);

		bd->failed = debugfs_create_file(name, 0400, c->debug, bd,
						 &bfloat_failed_debug_ops);
	}
}

#endif

void bch_debug_exit(void)
{
	if (!IS_ERR_OR_NULL(bch_debug))
		debugfs_remove_recursive(bch_debug);
}

int __init bch_debug_init(void)
{
	int ret = 0;

	bch_debug = debugfs_create_dir("bcache", NULL);
	return ret;
}