v4.19.13 snapshot.
diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c
new file mode 100644
index 0000000..06da66b
--- /dev/null
+++ b/drivers/md/bcache/debug.c
@@ -0,0 +1,264 @@
+// 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)) * \
+ block_bytes(b->c))
+
+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, PTR_CACHE(b->c, &b->key, 0)->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);
+
+ 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));
+
+ 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)
+{
+ struct bio *check;
+ struct bio_vec bv, cbv;
+ struct bvec_iter iter, citer = { 0 };
+
+ check = bio_kmalloc(GFP_NOIO, bio_segments(bio));
+ if (!check)
+ return;
+ check->bi_disk = bio->bi_disk;
+ check->bi_opf = 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 = kmap_atomic(bv.bv_page);
+ void *p2;
+
+ cbv = bio_iter_iovec(check, citer);
+ p2 = page_address(cbv.bv_page);
+
+ cache_set_err_on(memcmp(p1 + bv.bv_offset,
+ p2 + bv.bv_offset,
+ bv.bv_len),
+ dc->disk.c,
+ "verify failed at dev %s sector %llu",
+ dc->backing_dev_name,
+ (uint64_t) bio->bi_iter.bi_sector);
+
+ kunmap_atomic(p1);
+ bio_advance_iter(check, &citer, bv.bv_len);
+ }
+
+ bio_free_pages(check);
+out_put:
+ bio_put(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);
+ int err = copy_to_user(buf, i->buf, bytes);
+
+ if (err)
+ return err;
+
+ 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(sizeof(struct dump_iterator), GFP_KERNEL);
+ 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->sb.set_uuid);
+ c->debug = debugfs_create_file(name, 0400, bcache_debug, c,
+ &cache_set_debug_ops);
+ }
+}
+
+#endif
+
+void bch_debug_exit(void)
+{
+ if (!IS_ERR_OR_NULL(bcache_debug))
+ debugfs_remove_recursive(bcache_debug);
+}
+
+void __init bch_debug_init(struct kobject *kobj)
+{
+ /*
+ * it is unnecessary to check return value of
+ * debugfs_create_file(), we should not care
+ * about this.
+ */
+ bcache_debug = debugfs_create_dir("bcache", NULL);
+}