// SPDX-License-Identifier: GPL-2.0
/*
 * Assorted bcache debug code
 *
 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
 * Copyright 2012 Google, Inc.
 */

#include "bcache.h"
#include "btree.h"
#include "debug.h"
#include "extents.h"

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

struct dentry *bcache_debug;

#ifdef CONFIG_BCACHE_DEBUG

#define for_each_written_bset(b, start, i)                              \
        for (i = (start);                                               \
             (void *) i < (void *) (start) + (KEY_SIZE(&b->key) << 9) &&\
             i->seq == (start)->seq;                                    \
             i = (void *) i + set_blocks(i, block_bytes(b->c->cache)) * \
                 block_bytes(b->c->cache))

void bch_btree_verify(struct btree *b)
{
        struct btree *v = b->c->verify_data;
        struct bset *ondisk, *sorted, *inmemory;
        struct bio *bio;

        if (!b->c->verify || !b->c->verify_ondisk)
                return;

        down(&b->io_mutex);
        mutex_lock(&b->c->verify_lock);

        ondisk = b->c->verify_ondisk;
        sorted = b->c->verify_data->keys.set->data;
        inmemory = b->keys.set->data;

        bkey_copy(&v->key, &b->key);
        v->written = 0;
        v->level = b->level;
        v->keys.ops = b->keys.ops;

        bio = bch_bbio_alloc(b->c);
        bio_set_dev(bio, b->c->cache->bdev);
        bio->bi_iter.bi_sector  = PTR_OFFSET(&b->key, 0);
        bio->bi_iter.bi_size    = KEY_SIZE(&v->key) << 9;
        bio->bi_opf             = REQ_OP_READ | REQ_META;
        bch_bio_map(bio, sorted);

        submit_bio_wait(bio);
        bch_bbio_free(bio, b->c);

        memcpy(ondisk, sorted, KEY_SIZE(&v->key) << 9);

        bch_btree_node_read_done(v);
        sorted = v->keys.set->data;

        if (inmemory->keys != sorted->keys ||
            memcmp(inmemory->start,
                   sorted->start,
                   (void *) bset_bkey_last(inmemory) -
                   (void *) inmemory->start)) {
                struct bset *i;
                unsigned int j;

                console_lock();

                pr_err("*** in memory:\n");
                bch_dump_bset(&b->keys, inmemory, 0);

                pr_err("*** read back in:\n");
                bch_dump_bset(&v->keys, sorted, 0);

                for_each_written_bset(b, ondisk, i) {
                        unsigned int block = ((void *) i - (void *) ondisk) /
                                block_bytes(b->c->cache);

                        pr_err("*** on disk block %u:\n", block);
                        bch_dump_bset(&b->keys, i, block);
                }

                pr_err("*** block %zu not written\n",
                       ((void *) i - (void *) ondisk) / block_bytes(b->c->cache));

                for (j = 0; j < inmemory->keys; j++)
                        if (inmemory->d[j] != sorted->d[j])
                                break;

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

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

        mutex_unlock(&b->c->verify_lock);
        up(&b->io_mutex);
}

void bch_data_verify(struct cached_dev *dc, struct bio *bio)
{
        unsigned int nr_segs = bio_segments(bio);
        struct bio *check;
        struct bio_vec bv, cbv;
        struct bvec_iter iter, citer = { 0 };

        check = bio_kmalloc(nr_segs, GFP_NOIO);
        if (!check)
                return;
        bio_init_inline(check, bio->bi_bdev, nr_segs, REQ_OP_READ);
        check->bi_iter.bi_sector = bio->bi_iter.bi_sector;
        check->bi_iter.bi_size = bio->bi_iter.bi_size;

        bch_bio_map(check, NULL);
        if (bch_bio_alloc_pages(check, GFP_NOIO))
                goto out_put;

        submit_bio_wait(check);

        citer.bi_size = UINT_MAX;
        bio_for_each_segment(bv, bio, iter) {
                void *p1 = bvec_kmap_local(&bv);
                void *p2;

                cbv = bio_iter_iovec(check, citer);
                p2 = bvec_kmap_local(&cbv);

                cache_set_err_on(memcmp(p1, p2, bv.bv_len),
                                 dc->disk.c,
                                 "verify failed at dev %pg sector %llu",
                                 dc->bdev,
                                 (uint64_t) bio->bi_iter.bi_sector);

                kunmap_local(p2);
                kunmap_local(p1);
                bio_advance_iter(check, &citer, bv.bv_len);
        }

        bio_free_pages(check);
out_put:
        bio_uninit(check);
        kfree(check);
}

#endif

#ifdef CONFIG_DEBUG_FS

/* XXX: cache set refcounting */

struct dump_iterator {
        char                    buf[PAGE_SIZE];
        size_t                  bytes;
        struct cache_set        *c;
        struct keybuf           keys;
};

static bool dump_pred(struct keybuf *buf, struct bkey *k)
{
        return true;
}

static ssize_t bch_dump_read(struct file *file, char __user *buf,
                             size_t size, loff_t *ppos)
{
        struct dump_iterator *i = file->private_data;
        ssize_t ret = 0;
        char kbuf[80];

        while (size) {
                struct keybuf_key *w;
                unsigned int bytes = min(i->bytes, size);

                if (copy_to_user(buf, i->buf, bytes))
                        return -EFAULT;

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

                if (i->bytes)
                        break;

                w = bch_keybuf_next_rescan(i->c, &i->keys, &MAX_KEY, dump_pred);
                if (!w)
                        break;

                bch_extent_to_text(kbuf, sizeof(kbuf), &w->key);
                i->bytes = snprintf(i->buf, PAGE_SIZE, "%s\n", kbuf);
                bch_keybuf_del(&i->keys, w);
        }

        return ret;
}

static int bch_dump_open(struct inode *inode, struct file *file)
{
        struct cache_set *c = inode->i_private;
        struct dump_iterator *i;

        i = kzalloc_obj(struct dump_iterator);
        if (!i)
                return -ENOMEM;

        file->private_data = i;
        i->c = c;
        bch_keybuf_init(&i->keys);
        i->keys.last_scanned = KEY(0, 0, 0);

        return 0;
}

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

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

void bch_debug_init_cache_set(struct cache_set *c)
{
        if (!IS_ERR_OR_NULL(bcache_debug)) {
                char name[50];

                snprintf(name, 50, "bcache-%pU", c->set_uuid);
                c->debug = debugfs_create_file(name, 0400, bcache_debug, c,
                                               &cache_set_debug_ops);
        }
}

#endif

void bch_debug_exit(void)
{
        debugfs_remove_recursive(bcache_debug);
}

void __init bch_debug_init(void)
{
        /*
         * it is unnecessary to check return value of
         * debugfs_create_file(), we should not care
         * about this.
         */
        bcache_debug = debugfs_create_dir("bcache", NULL);
}