1 files changed, 515 insertions, 0 deletions

diff --git a/drivers/md/dm-dust.c b/drivers/md/dm-dust.c
new file mode 100644
index 000000000000..845f376a72d9
--- /dev/null
+++ b/drivers/md/dm-dust.c
@@ -0,0 +1,515 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018 Red Hat, Inc.
+ *
+ * This is a test "dust" device, which fails reads on specified
+ * sectors, emulating the behavior of a hard disk drive sending
+ * a "Read Medium Error" sense.
+ *
+ */
+
+#include <linux/device-mapper.h>
+#include <linux/module.h>
+#include <linux/rbtree.h>
+
+#define DM_MSG_PREFIX "dust"
+
+struct badblock {
+	struct rb_node node;
+	sector_t bb;
+};
+
+struct dust_device {
+	struct dm_dev *dev;
+	struct rb_root badblocklist;
+	unsigned long long badblock_count;
+	spinlock_t dust_lock;
+	unsigned int blksz;
+	unsigned int sect_per_block;
+	sector_t start;
+	bool fail_read_on_bb:1;
+	bool quiet_mode:1;
+};
+
+static struct badblock *dust_rb_search(struct rb_root *root, sector_t blk)
+{
+	struct rb_node *node = root->rb_node;
+
+	while (node) {
+		struct badblock *bblk = rb_entry(node, struct badblock, node);
+
+		if (bblk->bb > blk)
+			node = node->rb_left;
+		else if (bblk->bb < blk)
+			node = node->rb_right;
+		else
+			return bblk;
+	}
+
+	return NULL;
+}
+
+static bool dust_rb_insert(struct rb_root *root, struct badblock *new)
+{
+	struct badblock *bblk;
+	struct rb_node **link = &root->rb_node, *parent = NULL;
+	sector_t value = new->bb;
+
+	while (*link) {
+		parent = *link;
+		bblk = rb_entry(parent, struct badblock, node);
+
+		if (bblk->bb > value)
+			link = &(*link)->rb_left;
+		else if (bblk->bb < value)
+			link = &(*link)->rb_right;
+		else
+			return false;
+	}
+
+	rb_link_node(&new->node, parent, link);
+	rb_insert_color(&new->node, root);
+
+	return true;
+}
+
+static int dust_remove_block(struct dust_device *dd, unsigned long long block)
+{
+	struct badblock *bblock;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dd->dust_lock, flags);
+	bblock = dust_rb_search(&dd->badblocklist, block * dd->sect_per_block);
+
+	if (bblock == NULL) {
+		if (!dd->quiet_mode) {
+			DMERR("%s: block %llu not found in badblocklist",
+			      __func__, block);
+		}
+		spin_unlock_irqrestore(&dd->dust_lock, flags);
+		return -EINVAL;
+	}
+
+	rb_erase(&bblock->node, &dd->badblocklist);
+	dd->badblock_count--;
+	if (!dd->quiet_mode)
+		DMINFO("%s: badblock removed at block %llu", __func__, block);
+	kfree(bblock);
+	spin_unlock_irqrestore(&dd->dust_lock, flags);
+
+	return 0;
+}
+
+static int dust_add_block(struct dust_device *dd, unsigned long long block)
+{
+	struct badblock *bblock;
+	unsigned long flags;
+
+	bblock = kmalloc(sizeof(*bblock), GFP_KERNEL);
+	if (bblock == NULL) {
+		if (!dd->quiet_mode)
+			DMERR("%s: badblock allocation failed", __func__);
+		return -ENOMEM;
+	}
+
+	spin_lock_irqsave(&dd->dust_lock, flags);
+	bblock->bb = block * dd->sect_per_block;
+	if (!dust_rb_insert(&dd->badblocklist, bblock)) {
+		if (!dd->quiet_mode) {
+			DMERR("%s: block %llu already in badblocklist",
+			      __func__, block);
+		}
+		spin_unlock_irqrestore(&dd->dust_lock, flags);
+		kfree(bblock);
+		return -EINVAL;
+	}
+
+	dd->badblock_count++;
+	if (!dd->quiet_mode)
+		DMINFO("%s: badblock added at block %llu", __func__, block);
+	spin_unlock_irqrestore(&dd->dust_lock, flags);
+
+	return 0;
+}
+
+static int dust_query_block(struct dust_device *dd, unsigned long long block)
+{
+	struct badblock *bblock;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dd->dust_lock, flags);
+	bblock = dust_rb_search(&dd->badblocklist, block * dd->sect_per_block);
+	if (bblock != NULL)
+		DMINFO("%s: block %llu found in badblocklist", __func__, block);
+	else
+		DMINFO("%s: block %llu not found in badblocklist", __func__, block);
+	spin_unlock_irqrestore(&dd->dust_lock, flags);
+
+	return 0;
+}
+
+static int __dust_map_read(struct dust_device *dd, sector_t thisblock)
+{
+	struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);
+
+	if (bblk)
+		return DM_MAPIO_KILL;
+
+	return DM_MAPIO_REMAPPED;
+}
+
+static int dust_map_read(struct dust_device *dd, sector_t thisblock,
+			 bool fail_read_on_bb)
+{
+	unsigned long flags;
+	int ret = DM_MAPIO_REMAPPED;
+
+	if (fail_read_on_bb) {
+		spin_lock_irqsave(&dd->dust_lock, flags);
+		ret = __dust_map_read(dd, thisblock);
+		spin_unlock_irqrestore(&dd->dust_lock, flags);
+	}
+
+	return ret;
+}
+
+static void __dust_map_write(struct dust_device *dd, sector_t thisblock)
+{
+	struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);
+
+	if (bblk) {
+		rb_erase(&bblk->node, &dd->badblocklist);
+		dd->badblock_count--;
+		kfree(bblk);
+		if (!dd->quiet_mode) {
+			sector_div(thisblock, dd->sect_per_block);
+			DMINFO("block %llu removed from badblocklist by write",
+			       (unsigned long long)thisblock);
+		}
+	}
+}
+
+static int dust_map_write(struct dust_device *dd, sector_t thisblock,
+			  bool fail_read_on_bb)
+{
+	unsigned long flags;
+
+	if (fail_read_on_bb) {
+		spin_lock_irqsave(&dd->dust_lock, flags);
+		__dust_map_write(dd, thisblock);
+		spin_unlock_irqrestore(&dd->dust_lock, flags);
+	}
+
+	return DM_MAPIO_REMAPPED;
+}
+
+static int dust_map(struct dm_target *ti, struct bio *bio)
+{
+	struct dust_device *dd = ti->private;
+	int ret;
+
+	bio_set_dev(bio, dd->dev->bdev);
+	bio->bi_iter.bi_sector = dd->start + dm_target_offset(ti, bio->bi_iter.bi_sector);
+
+	if (bio_data_dir(bio) == READ)
+		ret = dust_map_read(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb);
+	else
+		ret = dust_map_write(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb);
+
+	return ret;
+}
+
+static bool __dust_clear_badblocks(struct rb_root *tree,
+				   unsigned long long count)
+{
+	struct rb_node *node = NULL, *nnode = NULL;
+
+	nnode = rb_first(tree);
+	if (nnode == NULL) {
+		BUG_ON(count != 0);
+		return false;
+	}
+
+	while (nnode) {
+		node = nnode;
+		nnode = rb_next(node);
+		rb_erase(node, tree);
+		count--;
+		kfree(node);
+	}
+	BUG_ON(count != 0);
+	BUG_ON(tree->rb_node != NULL);
+
+	return true;
+}
+
+static int dust_clear_badblocks(struct dust_device *dd)
+{
+	unsigned long flags;
+	struct rb_root badblocklist;
+	unsigned long long badblock_count;
+
+	spin_lock_irqsave(&dd->dust_lock, flags);
+	badblocklist = dd->badblocklist;
+	badblock_count = dd->badblock_count;
+	dd->badblocklist = RB_ROOT;
+	dd->badblock_count = 0;
+	spin_unlock_irqrestore(&dd->dust_lock, flags);
+
+	if (!__dust_clear_badblocks(&badblocklist, badblock_count))
+		DMINFO("%s: no badblocks found", __func__);
+	else
+		DMINFO("%s: badblocks cleared", __func__);
+
+	return 0;
+}
+
+/*
+ * Target parameters:
+ *
+ * <device_path> <offset> <blksz>
+ *
+ * device_path: path to the block device
+ * offset: offset to data area from start of device_path
+ * blksz: block size (minimum 512, maximum 1073741824, must be a power of 2)
+ */
+static int dust_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+	struct dust_device *dd;
+	unsigned long long tmp;
+	char dummy;
+	unsigned int blksz;
+	unsigned int sect_per_block;
+	sector_t DUST_MAX_BLKSZ_SECTORS = 2097152;
+	sector_t max_block_sectors = min(ti->len, DUST_MAX_BLKSZ_SECTORS);
+
+	if (argc != 3) {
+		ti->error = "Invalid argument count";
+		return -EINVAL;
+	}
+
+	if (kstrtouint(argv[2], 10, &blksz) || !blksz) {
+		ti->error = "Invalid block size parameter";
+		return -EINVAL;
+	}
+
+	if (blksz < 512) {
+		ti->error = "Block size must be at least 512";
+		return -EINVAL;
+	}
+
+	if (!is_power_of_2(blksz)) {
+		ti->error = "Block size must be a power of 2";
+		return -EINVAL;
+	}
+
+	if (to_sector(blksz) > max_block_sectors) {
+		ti->error = "Block size is too large";
+		return -EINVAL;
+	}
+
+	sect_per_block = (blksz >> SECTOR_SHIFT);
+
+	if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {
+		ti->error = "Invalid device offset sector";
+		return -EINVAL;
+	}
+
+	dd = kzalloc(sizeof(struct dust_device), GFP_KERNEL);
+	if (dd == NULL) {
+		ti->error = "Cannot allocate context";
+		return -ENOMEM;
+	}
+
+	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dd->dev)) {
+		ti->error = "Device lookup failed";
+		kfree(dd);
+		return -EINVAL;
+	}
+
+	dd->sect_per_block = sect_per_block;
+	dd->blksz = blksz;
+	dd->start = tmp;
+
+	/*
+	 * Whether to fail a read on a "bad" block.
+	 * Defaults to false; enabled later by message.
+	 */
+	dd->fail_read_on_bb = false;
+
+	/*
+	 * Initialize bad block list rbtree.
+	 */
+	dd->badblocklist = RB_ROOT;
+	dd->badblock_count = 0;
+	spin_lock_init(&dd->dust_lock);
+
+	dd->quiet_mode = false;
+
+	BUG_ON(dm_set_target_max_io_len(ti, dd->sect_per_block) != 0);
+
+	ti->num_discard_bios = 1;
+	ti->num_flush_bios = 1;
+	ti->private = dd;
+
+	return 0;
+}
+
+static void dust_dtr(struct dm_target *ti)
+{
+	struct dust_device *dd = ti->private;
+
+	__dust_clear_badblocks(&dd->badblocklist, dd->badblock_count);
+	dm_put_device(ti, dd->dev);
+	kfree(dd);
+}
+
+static int dust_message(struct dm_target *ti, unsigned int argc, char **argv,
+			char *result_buf, unsigned int maxlen)
+{
+	struct dust_device *dd = ti->private;
+	sector_t size = i_size_read(dd->dev->bdev->bd_inode) >> SECTOR_SHIFT;
+	bool invalid_msg = false;
+	int result = -EINVAL;
+	unsigned long long tmp, block;
+	unsigned long flags;
+	char dummy;
+
+	if (argc == 1) {
+		if (!strcasecmp(argv[0], "addbadblock") ||
+		    !strcasecmp(argv[0], "removebadblock") ||
+		    !strcasecmp(argv[0], "queryblock")) {
+			DMERR("%s requires an additional argument", argv[0]);
+		} else if (!strcasecmp(argv[0], "disable")) {
+			DMINFO("disabling read failures on bad sectors");
+			dd->fail_read_on_bb = false;
+			result = 0;
+		} else if (!strcasecmp(argv[0], "enable")) {
+			DMINFO("enabling read failures on bad sectors");
+			dd->fail_read_on_bb = true;
+			result = 0;
+		} else if (!strcasecmp(argv[0], "countbadblocks")) {
+			spin_lock_irqsave(&dd->dust_lock, flags);
+			DMINFO("countbadblocks: %llu badblock(s) found",
+			       dd->badblock_count);
+			spin_unlock_irqrestore(&dd->dust_lock, flags);
+			result = 0;
+		} else if (!strcasecmp(argv[0], "clearbadblocks")) {
+			result = dust_clear_badblocks(dd);
+		} else if (!strcasecmp(argv[0], "quiet")) {
+			if (!dd->quiet_mode)
+				dd->quiet_mode = true;
+			else
+				dd->quiet_mode = false;
+			result = 0;
+		} else {
+			invalid_msg = true;
+		}
+	} else if (argc == 2) {
+		if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1)
+			return result;
+
+		block = tmp;
+		sector_div(size, dd->sect_per_block);
+		if (block > size) {
+			DMERR("selected block value out of range");
+			return result;
+		}
+
+		if (!strcasecmp(argv[0], "addbadblock"))
+			result = dust_add_block(dd, block);
+		else if (!strcasecmp(argv[0], "removebadblock"))
+			result = dust_remove_block(dd, block);
+		else if (!strcasecmp(argv[0], "queryblock"))
+			result = dust_query_block(dd, block);
+		else
+			invalid_msg = true;
+
+	} else
+		DMERR("invalid number of arguments '%d'", argc);
+
+	if (invalid_msg)
+		DMERR("unrecognized message '%s' received", argv[0]);
+
+	return result;
+}
+
+static void dust_status(struct dm_target *ti, status_type_t type,
+			unsigned int status_flags, char *result, unsigned int maxlen)
+{
+	struct dust_device *dd = ti->private;
+	unsigned int sz = 0;
+
+	switch (type) {
+	case STATUSTYPE_INFO:
+		DMEMIT("%s %s %s", dd->dev->name,
+		       dd->fail_read_on_bb ? "fail_read_on_bad_block" : "bypass",
+		       dd->quiet_mode ? "quiet" : "verbose");
+		break;
+
+	case STATUSTYPE_TABLE:
+		DMEMIT("%s %llu %u", dd->dev->name,
+		       (unsigned long long)dd->start, dd->blksz);
+		break;
+	}
+}
+
+static int dust_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
+{
+	struct dust_device *dd = ti->private;
+	struct dm_dev *dev = dd->dev;
+
+	*bdev = dev->bdev;
+
+	/*
+	 * Only pass ioctls through if the device sizes match exactly.
+	 */
+	if (dd->start ||
+	    ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
+		return 1;
+
+	return 0;
+}
+
+static int dust_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn,
+				void *data)
+{
+	struct dust_device *dd = ti->private;
+
+	return fn(ti, dd->dev, dd->start, ti->len, data);
+}
+
+static struct target_type dust_target = {
+	.name = "dust",
+	.version = {1, 0, 0},
+	.module = THIS_MODULE,
+	.ctr = dust_ctr,
+	.dtr = dust_dtr,
+	.iterate_devices = dust_iterate_devices,
+	.map = dust_map,
+	.message = dust_message,
+	.status = dust_status,
+	.prepare_ioctl = dust_prepare_ioctl,
+};
+
+static int __init dm_dust_init(void)
+{
+	int result = dm_register_target(&dust_target);
+
+	if (result < 0)
+		DMERR("dm_register_target failed %d", result);
+
+	return result;
+}
+
+static void __exit dm_dust_exit(void)
+{
+	dm_unregister_target(&dust_target);
+}
+
+module_init(dm_dust_init);
+module_exit(dm_dust_exit);
+
+MODULE_DESCRIPTION(DM_NAME " dust test target");
+MODULE_AUTHOR("Bryan Gurney <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");