dm zoned: drive-managed zoned block device target
The dm-zoned device mapper target provides transparent write access
to zoned block devices (ZBC and ZAC compliant block devices).
dm-zoned hides to the device user (a file system or an application
doing raw block device accesses) any constraint imposed on write
requests by the device, equivalent to a drive-managed zoned block
device model.
Write requests are processed using a combination of on-disk buffering
using the device conventional zones and direct in-place processing for
requests aligned to a zone sequential write pointer position.
A background reclaim process implemented using dm_kcopyd_copy ensures
that conventional zones are always available for executing unaligned
write requests. The reclaim process overhead is minimized by managing
buffer zones in a least-recently-written order and first targeting the
oldest buffer zones. Doing so, blocks under regular write access (such
as metadata blocks of a file system) remain stored in conventional
zones, resulting in no apparent overhead.
dm-zoned implementation focus on simplicity and on minimizing overhead
(CPU, memory and storage overhead). For a 14TB host-managed disk with
256 MB zones, dm-zoned memory usage per disk instance is at most about
3 MB and as little as 5 zones will be used internally for storing metadata
and performing buffer zone reclaim operations. This is achieved using
zone level indirection rather than a full block indirection system for
managing block movement between zones.
dm-zoned primary target is host-managed zoned block devices but it can
also be used with host-aware device models to mitigate potential
device-side performance degradation due to excessive random writing.
Zoned block devices can be formatted and checked for use with the dm-zoned
target using the dmzadm utility available at:
https://github.com/hgst/dm-zoned-tools
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
[Mike Snitzer partly refactored Damien's original work to cleanup the code]
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c
new file mode 100644
index 0000000..4618441c
--- /dev/null
+++ b/drivers/md/dm-zoned-metadata.c
@@ -0,0 +1,2509 @@
+/*
+ * Copyright (C) 2017 Western Digital Corporation or its affiliates.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-zoned.h"
+
+#include <linux/module.h>
+#include <linux/crc32.h>
+
+#define DM_MSG_PREFIX "zoned metadata"
+
+/*
+ * Metadata version.
+ */
+#define DMZ_META_VER 1
+
+/*
+ * On-disk super block magic.
+ */
+#define DMZ_MAGIC ((((unsigned int)('D')) << 24) | \
+ (((unsigned int)('Z')) << 16) | \
+ (((unsigned int)('B')) << 8) | \
+ ((unsigned int)('D')))
+
+/*
+ * On disk super block.
+ * This uses only 512 B but uses on disk a full 4KB block. This block is
+ * followed on disk by the mapping table of chunks to zones and the bitmap
+ * blocks indicating zone block validity.
+ * The overall resulting metadata format is:
+ * (1) Super block (1 block)
+ * (2) Chunk mapping table (nr_map_blocks)
+ * (3) Bitmap blocks (nr_bitmap_blocks)
+ * All metadata blocks are stored in conventional zones, starting from the
+ * the first conventional zone found on disk.
+ */
+struct dmz_super {
+ /* Magic number */
+ __le32 magic; /* 4 */
+
+ /* Metadata version number */
+ __le32 version; /* 8 */
+
+ /* Generation number */
+ __le64 gen; /* 16 */
+
+ /* This block number */
+ __le64 sb_block; /* 24 */
+
+ /* The number of metadata blocks, including this super block */
+ __le32 nr_meta_blocks; /* 28 */
+
+ /* The number of sequential zones reserved for reclaim */
+ __le32 nr_reserved_seq; /* 32 */
+
+ /* The number of entries in the mapping table */
+ __le32 nr_chunks; /* 36 */
+
+ /* The number of blocks used for the chunk mapping table */
+ __le32 nr_map_blocks; /* 40 */
+
+ /* The number of blocks used for the block bitmaps */
+ __le32 nr_bitmap_blocks; /* 44 */
+
+ /* Checksum */
+ __le32 crc; /* 48 */
+
+ /* Padding to full 512B sector */
+ u8 reserved[464]; /* 512 */
+};
+
+/*
+ * Chunk mapping entry: entries are indexed by chunk number
+ * and give the zone ID (dzone_id) mapping the chunk on disk.
+ * This zone may be sequential or random. If it is a sequential
+ * zone, a second zone (bzone_id) used as a write buffer may
+ * also be specified. This second zone will always be a randomly
+ * writeable zone.
+ */
+struct dmz_map {
+ __le32 dzone_id;
+ __le32 bzone_id;
+};
+
+/*
+ * Chunk mapping table metadata: 512 8-bytes entries per 4KB block.
+ */
+#define DMZ_MAP_ENTRIES (DMZ_BLOCK_SIZE / sizeof(struct dmz_map))
+#define DMZ_MAP_ENTRIES_SHIFT (ilog2(DMZ_MAP_ENTRIES))
+#define DMZ_MAP_ENTRIES_MASK (DMZ_MAP_ENTRIES - 1)
+#define DMZ_MAP_UNMAPPED UINT_MAX
+
+/*
+ * Meta data block descriptor (for cached metadata blocks).
+ */
+struct dmz_mblock {
+ struct rb_node node;
+ struct list_head link;
+ sector_t no;
+ atomic_t ref;
+ unsigned long state;
+ struct page *page;
+ void *data;
+};
+
+/*
+ * Metadata block state flags.
+ */
+enum {
+ DMZ_META_DIRTY,
+ DMZ_META_READING,
+ DMZ_META_WRITING,
+ DMZ_META_ERROR,
+};
+
+/*
+ * Super block information (one per metadata set).
+ */
+struct dmz_sb {
+ sector_t block;
+ struct dmz_mblock *mblk;
+ struct dmz_super *sb;
+};
+
+/*
+ * In-memory metadata.
+ */
+struct dmz_metadata {
+ struct dmz_dev *dev;
+
+ sector_t zone_bitmap_size;
+ unsigned int zone_nr_bitmap_blocks;
+
+ unsigned int nr_bitmap_blocks;
+ unsigned int nr_map_blocks;
+
+ unsigned int nr_useable_zones;
+ unsigned int nr_meta_blocks;
+ unsigned int nr_meta_zones;
+ unsigned int nr_data_zones;
+ unsigned int nr_rnd_zones;
+ unsigned int nr_reserved_seq;
+ unsigned int nr_chunks;
+
+ /* Zone information array */
+ struct dm_zone *zones;
+
+ struct dm_zone *sb_zone;
+ struct dmz_sb sb[2];
+ unsigned int mblk_primary;
+ u64 sb_gen;
+ unsigned int min_nr_mblks;
+ unsigned int max_nr_mblks;
+ atomic_t nr_mblks;
+ struct rw_semaphore mblk_sem;
+ struct mutex mblk_flush_lock;
+ spinlock_t mblk_lock;
+ struct rb_root mblk_rbtree;
+ struct list_head mblk_lru_list;
+ struct list_head mblk_dirty_list;
+ struct shrinker mblk_shrinker;
+
+ /* Zone allocation management */
+ struct mutex map_lock;
+ struct dmz_mblock **map_mblk;
+ unsigned int nr_rnd;
+ atomic_t unmap_nr_rnd;
+ struct list_head unmap_rnd_list;
+ struct list_head map_rnd_list;
+
+ unsigned int nr_seq;
+ atomic_t unmap_nr_seq;
+ struct list_head unmap_seq_list;
+ struct list_head map_seq_list;
+
+ atomic_t nr_reserved_seq_zones;
+ struct list_head reserved_seq_zones_list;
+
+ wait_queue_head_t free_wq;
+};
+
+/*
+ * Various accessors
+ */
+unsigned int dmz_id(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ return ((unsigned int)(zone - zmd->zones));
+}
+
+sector_t dmz_start_sect(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ return dmz_id(zmd, zone) << zmd->dev->zone_nr_sectors_shift;
+}
+
+sector_t dmz_start_block(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ return dmz_id(zmd, zone) << zmd->dev->zone_nr_blocks_shift;
+}
+
+unsigned int dmz_nr_chunks(struct dmz_metadata *zmd)
+{
+ return zmd->nr_chunks;
+}
+
+unsigned int dmz_nr_rnd_zones(struct dmz_metadata *zmd)
+{
+ return zmd->nr_rnd;
+}
+
+unsigned int dmz_nr_unmap_rnd_zones(struct dmz_metadata *zmd)
+{
+ return atomic_read(&zmd->unmap_nr_rnd);
+}
+
+/*
+ * Lock/unlock mapping table.
+ * The map lock also protects all the zone lists.
+ */
+void dmz_lock_map(struct dmz_metadata *zmd)
+{
+ mutex_lock(&zmd->map_lock);
+}
+
+void dmz_unlock_map(struct dmz_metadata *zmd)
+{
+ mutex_unlock(&zmd->map_lock);
+}
+
+/*
+ * Lock/unlock metadata access. This is a "read" lock on a semaphore
+ * that prevents metadata flush from running while metadata are being
+ * modified. The actual metadata write mutual exclusion is achieved with
+ * the map lock and zone styate management (active and reclaim state are
+ * mutually exclusive).
+ */
+void dmz_lock_metadata(struct dmz_metadata *zmd)
+{
+ down_read(&zmd->mblk_sem);
+}
+
+void dmz_unlock_metadata(struct dmz_metadata *zmd)
+{
+ up_read(&zmd->mblk_sem);
+}
+
+/*
+ * Lock/unlock flush: prevent concurrent executions
+ * of dmz_flush_metadata as well as metadata modification in reclaim
+ * while flush is being executed.
+ */
+void dmz_lock_flush(struct dmz_metadata *zmd)
+{
+ mutex_lock(&zmd->mblk_flush_lock);
+}
+
+void dmz_unlock_flush(struct dmz_metadata *zmd)
+{
+ mutex_unlock(&zmd->mblk_flush_lock);
+}
+
+/*
+ * Allocate a metadata block.
+ */
+static struct dmz_mblock *dmz_alloc_mblock(struct dmz_metadata *zmd,
+ sector_t mblk_no)
+{
+ struct dmz_mblock *mblk = NULL;
+
+ /* See if we can reuse cached blocks */
+ if (zmd->max_nr_mblks && atomic_read(&zmd->nr_mblks) > zmd->max_nr_mblks) {
+ spin_lock(&zmd->mblk_lock);
+ mblk = list_first_entry_or_null(&zmd->mblk_lru_list,
+ struct dmz_mblock, link);
+ if (mblk) {
+ list_del_init(&mblk->link);
+ rb_erase(&mblk->node, &zmd->mblk_rbtree);
+ mblk->no = mblk_no;
+ }
+ spin_unlock(&zmd->mblk_lock);
+ if (mblk)
+ return mblk;
+ }
+
+ /* Allocate a new block */
+ mblk = kmalloc(sizeof(struct dmz_mblock), GFP_NOIO);
+ if (!mblk)
+ return NULL;
+
+ mblk->page = alloc_page(GFP_NOIO);
+ if (!mblk->page) {
+ kfree(mblk);
+ return NULL;
+ }
+
+ RB_CLEAR_NODE(&mblk->node);
+ INIT_LIST_HEAD(&mblk->link);
+ atomic_set(&mblk->ref, 0);
+ mblk->state = 0;
+ mblk->no = mblk_no;
+ mblk->data = page_address(mblk->page);
+
+ atomic_inc(&zmd->nr_mblks);
+
+ return mblk;
+}
+
+/*
+ * Free a metadata block.
+ */
+static void dmz_free_mblock(struct dmz_metadata *zmd, struct dmz_mblock *mblk)
+{
+ __free_pages(mblk->page, 0);
+ kfree(mblk);
+
+ atomic_dec(&zmd->nr_mblks);
+}
+
+/*
+ * Insert a metadata block in the rbtree.
+ */
+static void dmz_insert_mblock(struct dmz_metadata *zmd, struct dmz_mblock *mblk)
+{
+ struct rb_root *root = &zmd->mblk_rbtree;
+ struct rb_node **new = &(root->rb_node), *parent = NULL;
+ struct dmz_mblock *b;
+
+ /* Figure out where to put the new node */
+ while (*new) {
+ b = container_of(*new, struct dmz_mblock, node);
+ parent = *new;
+ new = (b->no < mblk->no) ? &((*new)->rb_left) : &((*new)->rb_right);
+ }
+
+ /* Add new node and rebalance tree */
+ rb_link_node(&mblk->node, parent, new);
+ rb_insert_color(&mblk->node, root);
+}
+
+/*
+ * Lookup a metadata block in the rbtree.
+ */
+static struct dmz_mblock *dmz_lookup_mblock(struct dmz_metadata *zmd,
+ sector_t mblk_no)
+{
+ struct rb_root *root = &zmd->mblk_rbtree;
+ struct rb_node *node = root->rb_node;
+ struct dmz_mblock *mblk;
+
+ while (node) {
+ mblk = container_of(node, struct dmz_mblock, node);
+ if (mblk->no == mblk_no)
+ return mblk;
+ node = (mblk->no < mblk_no) ? node->rb_left : node->rb_right;
+ }
+
+ return NULL;
+}
+
+/*
+ * Metadata block BIO end callback.
+ */
+static void dmz_mblock_bio_end_io(struct bio *bio)
+{
+ struct dmz_mblock *mblk = bio->bi_private;
+ int flag;
+
+ if (bio->bi_status)
+ set_bit(DMZ_META_ERROR, &mblk->state);
+
+ if (bio_op(bio) == REQ_OP_WRITE)
+ flag = DMZ_META_WRITING;
+ else
+ flag = DMZ_META_READING;
+
+ clear_bit_unlock(flag, &mblk->state);
+ smp_mb__after_atomic();
+ wake_up_bit(&mblk->state, flag);
+
+ bio_put(bio);
+}
+
+/*
+ * Read a metadata block from disk.
+ */
+static struct dmz_mblock *dmz_fetch_mblock(struct dmz_metadata *zmd,
+ sector_t mblk_no)
+{
+ struct dmz_mblock *mblk;
+ sector_t block = zmd->sb[zmd->mblk_primary].block + mblk_no;
+ struct bio *bio;
+
+ /* Get block and insert it */
+ mblk = dmz_alloc_mblock(zmd, mblk_no);
+ if (!mblk)
+ return NULL;
+
+ spin_lock(&zmd->mblk_lock);
+ atomic_inc(&mblk->ref);
+ set_bit(DMZ_META_READING, &mblk->state);
+ dmz_insert_mblock(zmd, mblk);
+ spin_unlock(&zmd->mblk_lock);
+
+ bio = bio_alloc(GFP_NOIO, 1);
+ if (!bio) {
+ dmz_free_mblock(zmd, mblk);
+ return NULL;
+ }
+
+ bio->bi_iter.bi_sector = dmz_blk2sect(block);
+ bio->bi_bdev = zmd->dev->bdev;
+ bio->bi_private = mblk;
+ bio->bi_end_io = dmz_mblock_bio_end_io;
+ bio_set_op_attrs(bio, REQ_OP_READ, REQ_META | REQ_PRIO);
+ bio_add_page(bio, mblk->page, DMZ_BLOCK_SIZE, 0);
+ submit_bio(bio);
+
+ return mblk;
+}
+
+/*
+ * Free metadata blocks.
+ */
+static unsigned long dmz_shrink_mblock_cache(struct dmz_metadata *zmd,
+ unsigned long limit)
+{
+ struct dmz_mblock *mblk;
+ unsigned long count = 0;
+
+ if (!zmd->max_nr_mblks)
+ return 0;
+
+ while (!list_empty(&zmd->mblk_lru_list) &&
+ atomic_read(&zmd->nr_mblks) > zmd->min_nr_mblks &&
+ count < limit) {
+ mblk = list_first_entry(&zmd->mblk_lru_list,
+ struct dmz_mblock, link);
+ list_del_init(&mblk->link);
+ rb_erase(&mblk->node, &zmd->mblk_rbtree);
+ dmz_free_mblock(zmd, mblk);
+ count++;
+ }
+
+ return count;
+}
+
+/*
+ * For mblock shrinker: get the number of unused metadata blocks in the cache.
+ */
+static unsigned long dmz_mblock_shrinker_count(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct dmz_metadata *zmd = container_of(shrink, struct dmz_metadata, mblk_shrinker);
+
+ return atomic_read(&zmd->nr_mblks);
+}
+
+/*
+ * For mblock shrinker: scan unused metadata blocks and shrink the cache.
+ */
+static unsigned long dmz_mblock_shrinker_scan(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct dmz_metadata *zmd = container_of(shrink, struct dmz_metadata, mblk_shrinker);
+ unsigned long count;
+
+ spin_lock(&zmd->mblk_lock);
+ count = dmz_shrink_mblock_cache(zmd, sc->nr_to_scan);
+ spin_unlock(&zmd->mblk_lock);
+
+ return count ? count : SHRINK_STOP;
+}
+
+/*
+ * Release a metadata block.
+ */
+static void dmz_release_mblock(struct dmz_metadata *zmd,
+ struct dmz_mblock *mblk)
+{
+
+ if (!mblk)
+ return;
+
+ spin_lock(&zmd->mblk_lock);
+
+ if (atomic_dec_and_test(&mblk->ref)) {
+ if (test_bit(DMZ_META_ERROR, &mblk->state)) {
+ rb_erase(&mblk->node, &zmd->mblk_rbtree);
+ dmz_free_mblock(zmd, mblk);
+ } else if (!test_bit(DMZ_META_DIRTY, &mblk->state)) {
+ list_add_tail(&mblk->link, &zmd->mblk_lru_list);
+ dmz_shrink_mblock_cache(zmd, 1);
+ }
+ }
+
+ spin_unlock(&zmd->mblk_lock);
+}
+
+/*
+ * Get a metadata block from the rbtree. If the block
+ * is not present, read it from disk.
+ */
+static struct dmz_mblock *dmz_get_mblock(struct dmz_metadata *zmd,
+ sector_t mblk_no)
+{
+ struct dmz_mblock *mblk;
+
+ /* Check rbtree */
+ spin_lock(&zmd->mblk_lock);
+ mblk = dmz_lookup_mblock(zmd, mblk_no);
+ if (mblk) {
+ /* Cache hit: remove block from LRU list */
+ if (atomic_inc_return(&mblk->ref) == 1 &&
+ !test_bit(DMZ_META_DIRTY, &mblk->state))
+ list_del_init(&mblk->link);
+ }
+ spin_unlock(&zmd->mblk_lock);
+
+ if (!mblk) {
+ /* Cache miss: read the block from disk */
+ mblk = dmz_fetch_mblock(zmd, mblk_no);
+ if (!mblk)
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /* Wait for on-going read I/O and check for error */
+ wait_on_bit_io(&mblk->state, DMZ_META_READING,
+ TASK_UNINTERRUPTIBLE);
+ if (test_bit(DMZ_META_ERROR, &mblk->state)) {
+ dmz_release_mblock(zmd, mblk);
+ return ERR_PTR(-EIO);
+ }
+
+ return mblk;
+}
+
+/*
+ * Mark a metadata block dirty.
+ */
+static void dmz_dirty_mblock(struct dmz_metadata *zmd, struct dmz_mblock *mblk)
+{
+ spin_lock(&zmd->mblk_lock);
+ if (!test_and_set_bit(DMZ_META_DIRTY, &mblk->state))
+ list_add_tail(&mblk->link, &zmd->mblk_dirty_list);
+ spin_unlock(&zmd->mblk_lock);
+}
+
+/*
+ * Issue a metadata block write BIO.
+ */
+static void dmz_write_mblock(struct dmz_metadata *zmd, struct dmz_mblock *mblk,
+ unsigned int set)
+{
+ sector_t block = zmd->sb[set].block + mblk->no;
+ struct bio *bio;
+
+ bio = bio_alloc(GFP_NOIO, 1);
+ if (!bio) {
+ set_bit(DMZ_META_ERROR, &mblk->state);
+ return;
+ }
+
+ set_bit(DMZ_META_WRITING, &mblk->state);
+
+ bio->bi_iter.bi_sector = dmz_blk2sect(block);
+ bio->bi_bdev = zmd->dev->bdev;
+ bio->bi_private = mblk;
+ bio->bi_end_io = dmz_mblock_bio_end_io;
+ bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_META | REQ_PRIO);
+ bio_add_page(bio, mblk->page, DMZ_BLOCK_SIZE, 0);
+ submit_bio(bio);
+}
+
+/*
+ * Read/write a metadata block.
+ */
+static int dmz_rdwr_block(struct dmz_metadata *zmd, int op, sector_t block,
+ struct page *page)
+{
+ struct bio *bio;
+ int ret;
+
+ bio = bio_alloc(GFP_NOIO, 1);
+ if (!bio)
+ return -ENOMEM;
+
+ bio->bi_iter.bi_sector = dmz_blk2sect(block);
+ bio->bi_bdev = zmd->dev->bdev;
+ bio_set_op_attrs(bio, op, REQ_SYNC | REQ_META | REQ_PRIO);
+ bio_add_page(bio, page, DMZ_BLOCK_SIZE, 0);
+ ret = submit_bio_wait(bio);
+ bio_put(bio);
+
+ return ret;
+}
+
+/*
+ * Write super block of the specified metadata set.
+ */
+static int dmz_write_sb(struct dmz_metadata *zmd, unsigned int set)
+{
+ sector_t block = zmd->sb[set].block;
+ struct dmz_mblock *mblk = zmd->sb[set].mblk;
+ struct dmz_super *sb = zmd->sb[set].sb;
+ u64 sb_gen = zmd->sb_gen + 1;
+ int ret;
+
+ sb->magic = cpu_to_le32(DMZ_MAGIC);
+ sb->version = cpu_to_le32(DMZ_META_VER);
+
+ sb->gen = cpu_to_le64(sb_gen);
+
+ sb->sb_block = cpu_to_le64(block);
+ sb->nr_meta_blocks = cpu_to_le32(zmd->nr_meta_blocks);
+ sb->nr_reserved_seq = cpu_to_le32(zmd->nr_reserved_seq);
+ sb->nr_chunks = cpu_to_le32(zmd->nr_chunks);
+
+ sb->nr_map_blocks = cpu_to_le32(zmd->nr_map_blocks);
+ sb->nr_bitmap_blocks = cpu_to_le32(zmd->nr_bitmap_blocks);
+
+ sb->crc = 0;
+ sb->crc = cpu_to_le32(crc32_le(sb_gen, (unsigned char *)sb, DMZ_BLOCK_SIZE));
+
+ ret = dmz_rdwr_block(zmd, REQ_OP_WRITE, block, mblk->page);
+ if (ret == 0)
+ ret = blkdev_issue_flush(zmd->dev->bdev, GFP_KERNEL, NULL);
+
+ return ret;
+}
+
+/*
+ * Write dirty metadata blocks to the specified set.
+ */
+static int dmz_write_dirty_mblocks(struct dmz_metadata *zmd,
+ struct list_head *write_list,
+ unsigned int set)
+{
+ struct dmz_mblock *mblk;
+ struct blk_plug plug;
+ int ret = 0;
+
+ /* Issue writes */
+ blk_start_plug(&plug);
+ list_for_each_entry(mblk, write_list, link)
+ dmz_write_mblock(zmd, mblk, set);
+ blk_finish_plug(&plug);
+
+ /* Wait for completion */
+ list_for_each_entry(mblk, write_list, link) {
+ wait_on_bit_io(&mblk->state, DMZ_META_WRITING,
+ TASK_UNINTERRUPTIBLE);
+ if (test_bit(DMZ_META_ERROR, &mblk->state)) {
+ clear_bit(DMZ_META_ERROR, &mblk->state);
+ ret = -EIO;
+ }
+ }
+
+ /* Flush drive cache (this will also sync data) */
+ if (ret == 0)
+ ret = blkdev_issue_flush(zmd->dev->bdev, GFP_KERNEL, NULL);
+
+ return ret;
+}
+
+/*
+ * Log dirty metadata blocks.
+ */
+static int dmz_log_dirty_mblocks(struct dmz_metadata *zmd,
+ struct list_head *write_list)
+{
+ unsigned int log_set = zmd->mblk_primary ^ 0x1;
+ int ret;
+
+ /* Write dirty blocks to the log */
+ ret = dmz_write_dirty_mblocks(zmd, write_list, log_set);
+ if (ret)
+ return ret;
+
+ /*
+ * No error so far: now validate the log by updating the
+ * log index super block generation.
+ */
+ ret = dmz_write_sb(zmd, log_set);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+/*
+ * Flush dirty metadata blocks.
+ */
+int dmz_flush_metadata(struct dmz_metadata *zmd)
+{
+ struct dmz_mblock *mblk;
+ struct list_head write_list;
+ int ret;
+
+ if (WARN_ON(!zmd))
+ return 0;
+
+ INIT_LIST_HEAD(&write_list);
+
+ /*
+ * Make sure that metadata blocks are stable before logging: take
+ * the write lock on the metadata semaphore to prevent target BIOs
+ * from modifying metadata.
+ */
+ down_write(&zmd->mblk_sem);
+
+ /*
+ * This is called from the target flush work and reclaim work.
+ * Concurrent execution is not allowed.
+ */
+ dmz_lock_flush(zmd);
+
+ /* Get dirty blocks */
+ spin_lock(&zmd->mblk_lock);
+ list_splice_init(&zmd->mblk_dirty_list, &write_list);
+ spin_unlock(&zmd->mblk_lock);
+
+ /* If there are no dirty metadata blocks, just flush the device cache */
+ if (list_empty(&write_list)) {
+ ret = blkdev_issue_flush(zmd->dev->bdev, GFP_KERNEL, NULL);
+ goto out;
+ }
+
+ /*
+ * The primary metadata set is still clean. Keep it this way until
+ * all updates are successful in the secondary set. That is, use
+ * the secondary set as a log.
+ */
+ ret = dmz_log_dirty_mblocks(zmd, &write_list);
+ if (ret)
+ goto out;
+
+ /*
+ * The log is on disk. It is now safe to update in place
+ * in the primary metadata set.
+ */
+ ret = dmz_write_dirty_mblocks(zmd, &write_list, zmd->mblk_primary);
+ if (ret)
+ goto out;
+
+ ret = dmz_write_sb(zmd, zmd->mblk_primary);
+ if (ret)
+ goto out;
+
+ while (!list_empty(&write_list)) {
+ mblk = list_first_entry(&write_list, struct dmz_mblock, link);
+ list_del_init(&mblk->link);
+
+ spin_lock(&zmd->mblk_lock);
+ clear_bit(DMZ_META_DIRTY, &mblk->state);
+ if (atomic_read(&mblk->ref) == 0)
+ list_add_tail(&mblk->link, &zmd->mblk_lru_list);
+ spin_unlock(&zmd->mblk_lock);
+ }
+
+ zmd->sb_gen++;
+out:
+ if (ret && !list_empty(&write_list)) {
+ spin_lock(&zmd->mblk_lock);
+ list_splice(&write_list, &zmd->mblk_dirty_list);
+ spin_unlock(&zmd->mblk_lock);
+ }
+
+ dmz_unlock_flush(zmd);
+ up_write(&zmd->mblk_sem);
+
+ return ret;
+}
+
+/*
+ * Check super block.
+ */
+static int dmz_check_sb(struct dmz_metadata *zmd, struct dmz_super *sb)
+{
+ unsigned int nr_meta_zones, nr_data_zones;
+ struct dmz_dev *dev = zmd->dev;
+ u32 crc, stored_crc;
+ u64 gen;
+
+ gen = le64_to_cpu(sb->gen);
+ stored_crc = le32_to_cpu(sb->crc);
+ sb->crc = 0;
+ crc = crc32_le(gen, (unsigned char *)sb, DMZ_BLOCK_SIZE);
+ if (crc != stored_crc) {
+ dmz_dev_err(dev, "Invalid checksum (needed 0x%08x, got 0x%08x)",
+ crc, stored_crc);
+ return -ENXIO;
+ }
+
+ if (le32_to_cpu(sb->magic) != DMZ_MAGIC) {
+ dmz_dev_err(dev, "Invalid meta magic (needed 0x%08x, got 0x%08x)",
+ DMZ_MAGIC, le32_to_cpu(sb->magic));
+ return -ENXIO;
+ }
+
+ if (le32_to_cpu(sb->version) != DMZ_META_VER) {
+ dmz_dev_err(dev, "Invalid meta version (needed %d, got %d)",
+ DMZ_META_VER, le32_to_cpu(sb->version));
+ return -ENXIO;
+ }
+
+ nr_meta_zones = (le32_to_cpu(sb->nr_meta_blocks) + dev->zone_nr_blocks - 1)
+ >> dev->zone_nr_blocks_shift;
+ if (!nr_meta_zones ||
+ nr_meta_zones >= zmd->nr_rnd_zones) {
+ dmz_dev_err(dev, "Invalid number of metadata blocks");
+ return -ENXIO;
+ }
+
+ if (!le32_to_cpu(sb->nr_reserved_seq) ||
+ le32_to_cpu(sb->nr_reserved_seq) >= (zmd->nr_useable_zones - nr_meta_zones)) {
+ dmz_dev_err(dev, "Invalid number of reserved sequential zones");
+ return -ENXIO;
+ }
+
+ nr_data_zones = zmd->nr_useable_zones -
+ (nr_meta_zones * 2 + le32_to_cpu(sb->nr_reserved_seq));
+ if (le32_to_cpu(sb->nr_chunks) > nr_data_zones) {
+ dmz_dev_err(dev, "Invalid number of chunks %u / %u",
+ le32_to_cpu(sb->nr_chunks), nr_data_zones);
+ return -ENXIO;
+ }
+
+ /* OK */
+ zmd->nr_meta_blocks = le32_to_cpu(sb->nr_meta_blocks);
+ zmd->nr_reserved_seq = le32_to_cpu(sb->nr_reserved_seq);
+ zmd->nr_chunks = le32_to_cpu(sb->nr_chunks);
+ zmd->nr_map_blocks = le32_to_cpu(sb->nr_map_blocks);
+ zmd->nr_bitmap_blocks = le32_to_cpu(sb->nr_bitmap_blocks);
+ zmd->nr_meta_zones = nr_meta_zones;
+ zmd->nr_data_zones = nr_data_zones;
+
+ return 0;
+}
+
+/*
+ * Read the first or second super block from disk.
+ */
+static int dmz_read_sb(struct dmz_metadata *zmd, unsigned int set)
+{
+ return dmz_rdwr_block(zmd, REQ_OP_READ, zmd->sb[set].block,
+ zmd->sb[set].mblk->page);
+}
+
+/*
+ * Determine the position of the secondary super blocks on disk.
+ * This is used only if a corruption of the primary super block
+ * is detected.
+ */
+static int dmz_lookup_secondary_sb(struct dmz_metadata *zmd)
+{
+ unsigned int zone_nr_blocks = zmd->dev->zone_nr_blocks;
+ struct dmz_mblock *mblk;
+ int i;
+
+ /* Allocate a block */
+ mblk = dmz_alloc_mblock(zmd, 0);
+ if (!mblk)
+ return -ENOMEM;
+
+ zmd->sb[1].mblk = mblk;
+ zmd->sb[1].sb = mblk->data;
+
+ /* Bad first super block: search for the second one */
+ zmd->sb[1].block = zmd->sb[0].block + zone_nr_blocks;
+ for (i = 0; i < zmd->nr_rnd_zones - 1; i++) {
+ if (dmz_read_sb(zmd, 1) != 0)
+ break;
+ if (le32_to_cpu(zmd->sb[1].sb->magic) == DMZ_MAGIC)
+ return 0;
+ zmd->sb[1].block += zone_nr_blocks;
+ }
+
+ dmz_free_mblock(zmd, mblk);
+ zmd->sb[1].mblk = NULL;
+
+ return -EIO;
+}
+
+/*
+ * Read the first or second super block from disk.
+ */
+static int dmz_get_sb(struct dmz_metadata *zmd, unsigned int set)
+{
+ struct dmz_mblock *mblk;
+ int ret;
+
+ /* Allocate a block */
+ mblk = dmz_alloc_mblock(zmd, 0);
+ if (!mblk)
+ return -ENOMEM;
+
+ zmd->sb[set].mblk = mblk;
+ zmd->sb[set].sb = mblk->data;
+
+ /* Read super block */
+ ret = dmz_read_sb(zmd, set);
+ if (ret) {
+ dmz_free_mblock(zmd, mblk);
+ zmd->sb[set].mblk = NULL;
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * Recover a metadata set.
+ */
+static int dmz_recover_mblocks(struct dmz_metadata *zmd, unsigned int dst_set)
+{
+ unsigned int src_set = dst_set ^ 0x1;
+ struct page *page;
+ int i, ret;
+
+ dmz_dev_warn(zmd->dev, "Metadata set %u invalid: recovering", dst_set);
+
+ if (dst_set == 0)
+ zmd->sb[0].block = dmz_start_block(zmd, zmd->sb_zone);
+ else {
+ zmd->sb[1].block = zmd->sb[0].block +
+ (zmd->nr_meta_zones << zmd->dev->zone_nr_blocks_shift);
+ }
+
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ return -ENOMEM;
+
+ /* Copy metadata blocks */
+ for (i = 1; i < zmd->nr_meta_blocks; i++) {
+ ret = dmz_rdwr_block(zmd, REQ_OP_READ,
+ zmd->sb[src_set].block + i, page);
+ if (ret)
+ goto out;
+ ret = dmz_rdwr_block(zmd, REQ_OP_WRITE,
+ zmd->sb[dst_set].block + i, page);
+ if (ret)
+ goto out;
+ }
+
+ /* Finalize with the super block */
+ if (!zmd->sb[dst_set].mblk) {
+ zmd->sb[dst_set].mblk = dmz_alloc_mblock(zmd, 0);
+ if (!zmd->sb[dst_set].mblk) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ zmd->sb[dst_set].sb = zmd->sb[dst_set].mblk->data;
+ }
+
+ ret = dmz_write_sb(zmd, dst_set);
+out:
+ __free_pages(page, 0);
+
+ return ret;
+}
+
+/*
+ * Get super block from disk.
+ */
+static int dmz_load_sb(struct dmz_metadata *zmd)
+{
+ bool sb_good[2] = {false, false};
+ u64 sb_gen[2] = {0, 0};
+ int ret;
+
+ /* Read and check the primary super block */
+ zmd->sb[0].block = dmz_start_block(zmd, zmd->sb_zone);
+ ret = dmz_get_sb(zmd, 0);
+ if (ret) {
+ dmz_dev_err(zmd->dev, "Read primary super block failed");
+ return ret;
+ }
+
+ ret = dmz_check_sb(zmd, zmd->sb[0].sb);
+
+ /* Read and check secondary super block */
+ if (ret == 0) {
+ sb_good[0] = true;
+ zmd->sb[1].block = zmd->sb[0].block +
+ (zmd->nr_meta_zones << zmd->dev->zone_nr_blocks_shift);
+ ret = dmz_get_sb(zmd, 1);
+ } else
+ ret = dmz_lookup_secondary_sb(zmd);
+
+ if (ret) {
+ dmz_dev_err(zmd->dev, "Read secondary super block failed");
+ return ret;
+ }
+
+ ret = dmz_check_sb(zmd, zmd->sb[1].sb);
+ if (ret == 0)
+ sb_good[1] = true;
+
+ /* Use highest generation sb first */
+ if (!sb_good[0] && !sb_good[1]) {
+ dmz_dev_err(zmd->dev, "No valid super block found");
+ return -EIO;
+ }
+
+ if (sb_good[0])
+ sb_gen[0] = le64_to_cpu(zmd->sb[0].sb->gen);
+ else
+ ret = dmz_recover_mblocks(zmd, 0);
+
+ if (sb_good[1])
+ sb_gen[1] = le64_to_cpu(zmd->sb[1].sb->gen);
+ else
+ ret = dmz_recover_mblocks(zmd, 1);
+
+ if (ret) {
+ dmz_dev_err(zmd->dev, "Recovery failed");
+ return -EIO;
+ }
+
+ if (sb_gen[0] >= sb_gen[1]) {
+ zmd->sb_gen = sb_gen[0];
+ zmd->mblk_primary = 0;
+ } else {
+ zmd->sb_gen = sb_gen[1];
+ zmd->mblk_primary = 1;
+ }
+
+ dmz_dev_debug(zmd->dev, "Using super block %u (gen %llu)",
+ zmd->mblk_primary, zmd->sb_gen);
+
+ return 0;
+}
+
+/*
+ * Initialize a zone descriptor.
+ */
+static int dmz_init_zone(struct dmz_metadata *zmd, struct dm_zone *zone,
+ struct blk_zone *blkz)
+{
+ struct dmz_dev *dev = zmd->dev;
+
+ /* Ignore the eventual last runt (smaller) zone */
+ if (blkz->len != dev->zone_nr_sectors) {
+ if (blkz->start + blkz->len == dev->capacity)
+ return 0;
+ return -ENXIO;
+ }
+
+ INIT_LIST_HEAD(&zone->link);
+ atomic_set(&zone->refcount, 0);
+ zone->chunk = DMZ_MAP_UNMAPPED;
+
+ if (blkz->type == BLK_ZONE_TYPE_CONVENTIONAL) {
+ set_bit(DMZ_RND, &zone->flags);
+ zmd->nr_rnd_zones++;
+ } else if (blkz->type == BLK_ZONE_TYPE_SEQWRITE_REQ ||
+ blkz->type == BLK_ZONE_TYPE_SEQWRITE_PREF) {
+ set_bit(DMZ_SEQ, &zone->flags);
+ } else
+ return -ENXIO;
+
+ if (blkz->cond == BLK_ZONE_COND_OFFLINE)
+ set_bit(DMZ_OFFLINE, &zone->flags);
+ else if (blkz->cond == BLK_ZONE_COND_READONLY)
+ set_bit(DMZ_READ_ONLY, &zone->flags);
+
+ if (dmz_is_rnd(zone))
+ zone->wp_block = 0;
+ else
+ zone->wp_block = dmz_sect2blk(blkz->wp - blkz->start);
+
+ if (!dmz_is_offline(zone) && !dmz_is_readonly(zone)) {
+ zmd->nr_useable_zones++;
+ if (dmz_is_rnd(zone)) {
+ zmd->nr_rnd_zones++;
+ if (!zmd->sb_zone) {
+ /* Super block zone */
+ zmd->sb_zone = zone;
+ }
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Free zones descriptors.
+ */
+static void dmz_drop_zones(struct dmz_metadata *zmd)
+{
+ kfree(zmd->zones);
+ zmd->zones = NULL;
+}
+
+/*
+ * The size of a zone report in number of zones.
+ * This results in 4096*64B=256KB report zones commands.
+ */
+#define DMZ_REPORT_NR_ZONES 4096
+
+/*
+ * Allocate and initialize zone descriptors using the zone
+ * information from disk.
+ */
+static int dmz_init_zones(struct dmz_metadata *zmd)
+{
+ struct dmz_dev *dev = zmd->dev;
+ struct dm_zone *zone;
+ struct blk_zone *blkz;
+ unsigned int nr_blkz;
+ sector_t sector = 0;
+ int i, ret = 0;
+
+ /* Init */
+ zmd->zone_bitmap_size = dev->zone_nr_blocks >> 3;
+ zmd->zone_nr_bitmap_blocks = zmd->zone_bitmap_size >> DMZ_BLOCK_SHIFT;
+
+ /* Allocate zone array */
+ zmd->zones = kcalloc(dev->nr_zones, sizeof(struct dm_zone), GFP_KERNEL);
+ if (!zmd->zones)
+ return -ENOMEM;
+
+ dmz_dev_info(dev, "Using %zu B for zone information",
+ sizeof(struct dm_zone) * dev->nr_zones);
+
+ /* Get zone information */
+ nr_blkz = DMZ_REPORT_NR_ZONES;
+ blkz = kcalloc(nr_blkz, sizeof(struct blk_zone), GFP_KERNEL);
+ if (!blkz) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ /*
+ * Get zone information and initialize zone descriptors.
+ * At the same time, determine where the super block
+ * should be: first block of the first randomly writable
+ * zone.
+ */
+ zone = zmd->zones;
+ while (sector < dev->capacity) {
+ /* Get zone information */
+ nr_blkz = DMZ_REPORT_NR_ZONES;
+ ret = blkdev_report_zones(dev->bdev, sector, blkz,
+ &nr_blkz, GFP_KERNEL);
+ if (ret) {
+ dmz_dev_err(dev, "Report zones failed %d", ret);
+ goto out;
+ }
+
+ /* Process report */
+ for (i = 0; i < nr_blkz; i++) {
+ ret = dmz_init_zone(zmd, zone, &blkz[i]);
+ if (ret)
+ goto out;
+ sector += dev->zone_nr_sectors;
+ zone++;
+ }
+ }
+
+ /* The entire zone configuration of the disk should now be known */
+ if (sector < dev->capacity) {
+ dmz_dev_err(dev, "Failed to get correct zone information");
+ ret = -ENXIO;
+ }
+out:
+ kfree(blkz);
+ if (ret)
+ dmz_drop_zones(zmd);
+
+ return ret;
+}
+
+/*
+ * Update a zone information.
+ */
+static int dmz_update_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ unsigned int nr_blkz = 1;
+ struct blk_zone blkz;
+ int ret;
+
+ /* Get zone information from disk */
+ ret = blkdev_report_zones(zmd->dev->bdev, dmz_start_sect(zmd, zone),
+ &blkz, &nr_blkz, GFP_KERNEL);
+ if (ret) {
+ dmz_dev_err(zmd->dev, "Get zone %u report failed",
+ dmz_id(zmd, zone));
+ return ret;
+ }
+
+ clear_bit(DMZ_OFFLINE, &zone->flags);
+ clear_bit(DMZ_READ_ONLY, &zone->flags);
+ if (blkz.cond == BLK_ZONE_COND_OFFLINE)
+ set_bit(DMZ_OFFLINE, &zone->flags);
+ else if (blkz.cond == BLK_ZONE_COND_READONLY)
+ set_bit(DMZ_READ_ONLY, &zone->flags);
+
+ if (dmz_is_seq(zone))
+ zone->wp_block = dmz_sect2blk(blkz.wp - blkz.start);
+ else
+ zone->wp_block = 0;
+
+ return 0;
+}
+
+/*
+ * Check a zone write pointer position when the zone is marked
+ * with the sequential write error flag.
+ */
+static int dmz_handle_seq_write_err(struct dmz_metadata *zmd,
+ struct dm_zone *zone)
+{
+ unsigned int wp = 0;
+ int ret;
+
+ wp = zone->wp_block;
+ ret = dmz_update_zone(zmd, zone);
+ if (ret)
+ return ret;
+
+ dmz_dev_warn(zmd->dev, "Processing zone %u write error (zone wp %u/%u)",
+ dmz_id(zmd, zone), zone->wp_block, wp);
+
+ if (zone->wp_block < wp) {
+ dmz_invalidate_blocks(zmd, zone, zone->wp_block,
+ wp - zone->wp_block);
+ }
+
+ return 0;
+}
+
+static struct dm_zone *dmz_get(struct dmz_metadata *zmd, unsigned int zone_id)
+{
+ return &zmd->zones[zone_id];
+}
+
+/*
+ * Reset a zone write pointer.
+ */
+static int dmz_reset_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ int ret;
+
+ /*
+ * Ignore offline zones, read only zones,
+ * and conventional zones.
+ */
+ if (dmz_is_offline(zone) ||
+ dmz_is_readonly(zone) ||
+ dmz_is_rnd(zone))
+ return 0;
+
+ if (!dmz_is_empty(zone) || dmz_seq_write_err(zone)) {
+ struct dmz_dev *dev = zmd->dev;
+
+ ret = blkdev_reset_zones(dev->bdev,
+ dmz_start_sect(zmd, zone),
+ dev->zone_nr_sectors, GFP_KERNEL);
+ if (ret) {
+ dmz_dev_err(dev, "Reset zone %u failed %d",
+ dmz_id(zmd, zone), ret);
+ return ret;
+ }
+ }
+
+ /* Clear write error bit and rewind write pointer position */
+ clear_bit(DMZ_SEQ_WRITE_ERR, &zone->flags);
+ zone->wp_block = 0;
+
+ return 0;
+}
+
+static void dmz_get_zone_weight(struct dmz_metadata *zmd, struct dm_zone *zone);
+
+/*
+ * Initialize chunk mapping.
+ */
+static int dmz_load_mapping(struct dmz_metadata *zmd)
+{
+ struct dmz_dev *dev = zmd->dev;
+ struct dm_zone *dzone, *bzone;
+ struct dmz_mblock *dmap_mblk = NULL;
+ struct dmz_map *dmap;
+ unsigned int i = 0, e = 0, chunk = 0;
+ unsigned int dzone_id;
+ unsigned int bzone_id;
+
+ /* Metadata block array for the chunk mapping table */
+ zmd->map_mblk = kcalloc(zmd->nr_map_blocks,
+ sizeof(struct dmz_mblk *), GFP_KERNEL);
+ if (!zmd->map_mblk)
+ return -ENOMEM;
+
+ /* Get chunk mapping table blocks and initialize zone mapping */
+ while (chunk < zmd->nr_chunks) {
+ if (!dmap_mblk) {
+ /* Get mapping block */
+ dmap_mblk = dmz_get_mblock(zmd, i + 1);
+ if (IS_ERR(dmap_mblk))
+ return PTR_ERR(dmap_mblk);
+ zmd->map_mblk[i] = dmap_mblk;
+ dmap = (struct dmz_map *) dmap_mblk->data;
+ i++;
+ e = 0;
+ }
+
+ /* Check data zone */
+ dzone_id = le32_to_cpu(dmap[e].dzone_id);
+ if (dzone_id == DMZ_MAP_UNMAPPED)
+ goto next;
+
+ if (dzone_id >= dev->nr_zones) {
+ dmz_dev_err(dev, "Chunk %u mapping: invalid data zone ID %u",
+ chunk, dzone_id);
+ return -EIO;
+ }
+
+ dzone = dmz_get(zmd, dzone_id);
+ set_bit(DMZ_DATA, &dzone->flags);
+ dzone->chunk = chunk;
+ dmz_get_zone_weight(zmd, dzone);
+
+ if (dmz_is_rnd(dzone))
+ list_add_tail(&dzone->link, &zmd->map_rnd_list);
+ else
+ list_add_tail(&dzone->link, &zmd->map_seq_list);
+
+ /* Check buffer zone */
+ bzone_id = le32_to_cpu(dmap[e].bzone_id);
+ if (bzone_id == DMZ_MAP_UNMAPPED)
+ goto next;
+
+ if (bzone_id >= dev->nr_zones) {
+ dmz_dev_err(dev, "Chunk %u mapping: invalid buffer zone ID %u",
+ chunk, bzone_id);
+ return -EIO;
+ }
+
+ bzone = dmz_get(zmd, bzone_id);
+ if (!dmz_is_rnd(bzone)) {
+ dmz_dev_err(dev, "Chunk %u mapping: invalid buffer zone %u",
+ chunk, bzone_id);
+ return -EIO;
+ }
+
+ set_bit(DMZ_DATA, &bzone->flags);
+ set_bit(DMZ_BUF, &bzone->flags);
+ bzone->chunk = chunk;
+ bzone->bzone = dzone;
+ dzone->bzone = bzone;
+ dmz_get_zone_weight(zmd, bzone);
+ list_add_tail(&bzone->link, &zmd->map_rnd_list);
+next:
+ chunk++;
+ e++;
+ if (e >= DMZ_MAP_ENTRIES)
+ dmap_mblk = NULL;
+ }
+
+ /*
+ * At this point, only meta zones and mapped data zones were
+ * fully initialized. All remaining zones are unmapped data
+ * zones. Finish initializing those here.
+ */
+ for (i = 0; i < dev->nr_zones; i++) {
+ dzone = dmz_get(zmd, i);
+ if (dmz_is_meta(dzone))
+ continue;
+
+ if (dmz_is_rnd(dzone))
+ zmd->nr_rnd++;
+ else
+ zmd->nr_seq++;
+
+ if (dmz_is_data(dzone)) {
+ /* Already initialized */
+ continue;
+ }
+
+ /* Unmapped data zone */
+ set_bit(DMZ_DATA, &dzone->flags);
+ dzone->chunk = DMZ_MAP_UNMAPPED;
+ if (dmz_is_rnd(dzone)) {
+ list_add_tail(&dzone->link, &zmd->unmap_rnd_list);
+ atomic_inc(&zmd->unmap_nr_rnd);
+ } else if (atomic_read(&zmd->nr_reserved_seq_zones) < zmd->nr_reserved_seq) {
+ list_add_tail(&dzone->link, &zmd->reserved_seq_zones_list);
+ atomic_inc(&zmd->nr_reserved_seq_zones);
+ zmd->nr_seq--;
+ } else {
+ list_add_tail(&dzone->link, &zmd->unmap_seq_list);
+ atomic_inc(&zmd->unmap_nr_seq);
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Set a data chunk mapping.
+ */
+static void dmz_set_chunk_mapping(struct dmz_metadata *zmd, unsigned int chunk,
+ unsigned int dzone_id, unsigned int bzone_id)
+{
+ struct dmz_mblock *dmap_mblk = zmd->map_mblk[chunk >> DMZ_MAP_ENTRIES_SHIFT];
+ struct dmz_map *dmap = (struct dmz_map *) dmap_mblk->data;
+ int map_idx = chunk & DMZ_MAP_ENTRIES_MASK;
+
+ dmap[map_idx].dzone_id = cpu_to_le32(dzone_id);
+ dmap[map_idx].bzone_id = cpu_to_le32(bzone_id);
+ dmz_dirty_mblock(zmd, dmap_mblk);
+}
+
+/*
+ * The list of mapped zones is maintained in LRU order.
+ * This rotates a zone at the end of its map list.
+ */
+static void __dmz_lru_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ if (list_empty(&zone->link))
+ return;
+
+ list_del_init(&zone->link);
+ if (dmz_is_seq(zone)) {
+ /* LRU rotate sequential zone */
+ list_add_tail(&zone->link, &zmd->map_seq_list);
+ } else {
+ /* LRU rotate random zone */
+ list_add_tail(&zone->link, &zmd->map_rnd_list);
+ }
+}
+
+/*
+ * The list of mapped random zones is maintained
+ * in LRU order. This rotates a zone at the end of the list.
+ */
+static void dmz_lru_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ __dmz_lru_zone(zmd, zone);
+ if (zone->bzone)
+ __dmz_lru_zone(zmd, zone->bzone);
+}
+
+/*
+ * Wait for any zone to be freed.
+ */
+static void dmz_wait_for_free_zones(struct dmz_metadata *zmd)
+{
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&zmd->free_wq, &wait, TASK_UNINTERRUPTIBLE);
+ dmz_unlock_map(zmd);
+ dmz_unlock_metadata(zmd);
+
+ io_schedule_timeout(HZ);
+
+ dmz_lock_metadata(zmd);
+ dmz_lock_map(zmd);
+ finish_wait(&zmd->free_wq, &wait);
+}
+
+/*
+ * Lock a zone for reclaim (set the zone RECLAIM bit).
+ * Returns false if the zone cannot be locked or if it is already locked
+ * and 1 otherwise.
+ */
+int dmz_lock_zone_reclaim(struct dm_zone *zone)
+{
+ /* Active zones cannot be reclaimed */
+ if (dmz_is_active(zone))
+ return 0;
+
+ return !test_and_set_bit(DMZ_RECLAIM, &zone->flags);
+}
+
+/*
+ * Clear a zone reclaim flag.
+ */
+void dmz_unlock_zone_reclaim(struct dm_zone *zone)
+{
+ WARN_ON(dmz_is_active(zone));
+ WARN_ON(!dmz_in_reclaim(zone));
+
+ clear_bit_unlock(DMZ_RECLAIM, &zone->flags);
+ smp_mb__after_atomic();
+ wake_up_bit(&zone->flags, DMZ_RECLAIM);
+}
+
+/*
+ * Wait for a zone reclaim to complete.
+ */
+static void dmz_wait_for_reclaim(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ dmz_unlock_map(zmd);
+ dmz_unlock_metadata(zmd);
+ wait_on_bit_timeout(&zone->flags, DMZ_RECLAIM, TASK_UNINTERRUPTIBLE, HZ);
+ dmz_lock_metadata(zmd);
+ dmz_lock_map(zmd);
+}
+
+/*
+ * Select a random write zone for reclaim.
+ */
+static struct dm_zone *dmz_get_rnd_zone_for_reclaim(struct dmz_metadata *zmd)
+{
+ struct dm_zone *dzone = NULL;
+ struct dm_zone *zone;
+
+ if (list_empty(&zmd->map_rnd_list))
+ return NULL;
+
+ list_for_each_entry(zone, &zmd->map_rnd_list, link) {
+ if (dmz_is_buf(zone))
+ dzone = zone->bzone;
+ else
+ dzone = zone;
+ if (dmz_lock_zone_reclaim(dzone))
+ return dzone;
+ }
+
+ return NULL;
+}
+
+/*
+ * Select a buffered sequential zone for reclaim.
+ */
+static struct dm_zone *dmz_get_seq_zone_for_reclaim(struct dmz_metadata *zmd)
+{
+ struct dm_zone *zone;
+
+ if (list_empty(&zmd->map_seq_list))
+ return NULL;
+
+ list_for_each_entry(zone, &zmd->map_seq_list, link) {
+ if (!zone->bzone)
+ continue;
+ if (dmz_lock_zone_reclaim(zone))
+ return zone;
+ }
+
+ return NULL;
+}
+
+/*
+ * Select a zone for reclaim.
+ */
+struct dm_zone *dmz_get_zone_for_reclaim(struct dmz_metadata *zmd)
+{
+ struct dm_zone *zone;
+
+ /*
+ * Search for a zone candidate to reclaim: 2 cases are possible.
+ * (1) There is no free sequential zones. Then a random data zone
+ * cannot be reclaimed. So choose a sequential zone to reclaim so
+ * that afterward a random zone can be reclaimed.
+ * (2) At least one free sequential zone is available, then choose
+ * the oldest random zone (data or buffer) that can be locked.
+ */
+ dmz_lock_map(zmd);
+ if (list_empty(&zmd->reserved_seq_zones_list))
+ zone = dmz_get_seq_zone_for_reclaim(zmd);
+ else
+ zone = dmz_get_rnd_zone_for_reclaim(zmd);
+ dmz_unlock_map(zmd);
+
+ return zone;
+}
+
+/*
+ * Activate a zone (increment its reference count).
+ */
+void dmz_activate_zone(struct dm_zone *zone)
+{
+ set_bit(DMZ_ACTIVE, &zone->flags);
+ atomic_inc(&zone->refcount);
+}
+
+/*
+ * Deactivate a zone. This decrement the zone reference counter
+ * and clears the active state of the zone once the count reaches 0,
+ * indicating that all BIOs to the zone have completed. Returns
+ * true if the zone was deactivated.
+ */
+void dmz_deactivate_zone(struct dm_zone *zone)
+{
+ if (atomic_dec_and_test(&zone->refcount)) {
+ WARN_ON(!test_bit(DMZ_ACTIVE, &zone->flags));
+ clear_bit_unlock(DMZ_ACTIVE, &zone->flags);
+ smp_mb__after_atomic();
+ }
+}
+
+/*
+ * Get the zone mapping a chunk, if the chunk is mapped already.
+ * If no mapping exist and the operation is WRITE, a zone is
+ * allocated and used to map the chunk.
+ * The zone returned will be set to the active state.
+ */
+struct dm_zone *dmz_get_chunk_mapping(struct dmz_metadata *zmd, unsigned int chunk, int op)
+{
+ struct dmz_mblock *dmap_mblk = zmd->map_mblk[chunk >> DMZ_MAP_ENTRIES_SHIFT];
+ struct dmz_map *dmap = (struct dmz_map *) dmap_mblk->data;
+ int dmap_idx = chunk & DMZ_MAP_ENTRIES_MASK;
+ unsigned int dzone_id;
+ struct dm_zone *dzone = NULL;
+ int ret = 0;
+
+ dmz_lock_map(zmd);
+again:
+ /* Get the chunk mapping */
+ dzone_id = le32_to_cpu(dmap[dmap_idx].dzone_id);
+ if (dzone_id == DMZ_MAP_UNMAPPED) {
+ /*
+ * Read or discard in unmapped chunks are fine. But for
+ * writes, we need a mapping, so get one.
+ */
+ if (op != REQ_OP_WRITE)
+ goto out;
+
+ /* Alloate a random zone */
+ dzone = dmz_alloc_zone(zmd, DMZ_ALLOC_RND);
+ if (!dzone) {
+ dmz_wait_for_free_zones(zmd);
+ goto again;
+ }
+
+ dmz_map_zone(zmd, dzone, chunk);
+
+ } else {
+ /* The chunk is already mapped: get the mapping zone */
+ dzone = dmz_get(zmd, dzone_id);
+ if (dzone->chunk != chunk) {
+ dzone = ERR_PTR(-EIO);
+ goto out;
+ }
+
+ /* Repair write pointer if the sequential dzone has error */
+ if (dmz_seq_write_err(dzone)) {
+ ret = dmz_handle_seq_write_err(zmd, dzone);
+ if (ret) {
+ dzone = ERR_PTR(-EIO);
+ goto out;
+ }
+ clear_bit(DMZ_SEQ_WRITE_ERR, &dzone->flags);
+ }
+ }
+
+ /*
+ * If the zone is being reclaimed, the chunk mapping may change
+ * to a different zone. So wait for reclaim and retry. Otherwise,
+ * activate the zone (this will prevent reclaim from touching it).
+ */
+ if (dmz_in_reclaim(dzone)) {
+ dmz_wait_for_reclaim(zmd, dzone);
+ goto again;
+ }
+ dmz_activate_zone(dzone);
+ dmz_lru_zone(zmd, dzone);
+out:
+ dmz_unlock_map(zmd);
+
+ return dzone;
+}
+
+/*
+ * Write and discard change the block validity of data zones and their buffer
+ * zones. Check here that valid blocks are still present. If all blocks are
+ * invalid, the zones can be unmapped on the fly without waiting for reclaim
+ * to do it.
+ */
+void dmz_put_chunk_mapping(struct dmz_metadata *zmd, struct dm_zone *dzone)
+{
+ struct dm_zone *bzone;
+
+ dmz_lock_map(zmd);
+
+ bzone = dzone->bzone;
+ if (bzone) {
+ if (dmz_weight(bzone))
+ dmz_lru_zone(zmd, bzone);
+ else {
+ /* Empty buffer zone: reclaim it */
+ dmz_unmap_zone(zmd, bzone);
+ dmz_free_zone(zmd, bzone);
+ bzone = NULL;
+ }
+ }
+
+ /* Deactivate the data zone */
+ dmz_deactivate_zone(dzone);
+ if (dmz_is_active(dzone) || bzone || dmz_weight(dzone))
+ dmz_lru_zone(zmd, dzone);
+ else {
+ /* Unbuffered inactive empty data zone: reclaim it */
+ dmz_unmap_zone(zmd, dzone);
+ dmz_free_zone(zmd, dzone);
+ }
+
+ dmz_unlock_map(zmd);
+}
+
+/*
+ * Allocate and map a random zone to buffer a chunk
+ * already mapped to a sequential zone.
+ */
+struct dm_zone *dmz_get_chunk_buffer(struct dmz_metadata *zmd,
+ struct dm_zone *dzone)
+{
+ struct dm_zone *bzone;
+
+ dmz_lock_map(zmd);
+again:
+ bzone = dzone->bzone;
+ if (bzone)
+ goto out;
+
+ /* Alloate a random zone */
+ bzone = dmz_alloc_zone(zmd, DMZ_ALLOC_RND);
+ if (!bzone) {
+ dmz_wait_for_free_zones(zmd);
+ goto again;
+ }
+
+ /* Update the chunk mapping */
+ dmz_set_chunk_mapping(zmd, dzone->chunk, dmz_id(zmd, dzone),
+ dmz_id(zmd, bzone));
+
+ set_bit(DMZ_BUF, &bzone->flags);
+ bzone->chunk = dzone->chunk;
+ bzone->bzone = dzone;
+ dzone->bzone = bzone;
+ list_add_tail(&bzone->link, &zmd->map_rnd_list);
+out:
+ dmz_unlock_map(zmd);
+
+ return bzone;
+}
+
+/*
+ * Get an unmapped (free) zone.
+ * This must be called with the mapping lock held.
+ */
+struct dm_zone *dmz_alloc_zone(struct dmz_metadata *zmd, unsigned long flags)
+{
+ struct list_head *list;
+ struct dm_zone *zone;
+
+ if (flags & DMZ_ALLOC_RND)
+ list = &zmd->unmap_rnd_list;
+ else
+ list = &zmd->unmap_seq_list;
+again:
+ if (list_empty(list)) {
+ /*
+ * No free zone: if this is for reclaim, allow using the
+ * reserved sequential zones.
+ */
+ if (!(flags & DMZ_ALLOC_RECLAIM) ||
+ list_empty(&zmd->reserved_seq_zones_list))
+ return NULL;
+
+ zone = list_first_entry(&zmd->reserved_seq_zones_list,
+ struct dm_zone, link);
+ list_del_init(&zone->link);
+ atomic_dec(&zmd->nr_reserved_seq_zones);
+ return zone;
+ }
+
+ zone = list_first_entry(list, struct dm_zone, link);
+ list_del_init(&zone->link);
+
+ if (dmz_is_rnd(zone))
+ atomic_dec(&zmd->unmap_nr_rnd);
+ else
+ atomic_dec(&zmd->unmap_nr_seq);
+
+ if (dmz_is_offline(zone)) {
+ dmz_dev_warn(zmd->dev, "Zone %u is offline", dmz_id(zmd, zone));
+ zone = NULL;
+ goto again;
+ }
+
+ return zone;
+}
+
+/*
+ * Free a zone.
+ * This must be called with the mapping lock held.
+ */
+void dmz_free_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ /* If this is a sequential zone, reset it */
+ if (dmz_is_seq(zone))
+ dmz_reset_zone(zmd, zone);
+
+ /* Return the zone to its type unmap list */
+ if (dmz_is_rnd(zone)) {
+ list_add_tail(&zone->link, &zmd->unmap_rnd_list);
+ atomic_inc(&zmd->unmap_nr_rnd);
+ } else if (atomic_read(&zmd->nr_reserved_seq_zones) <
+ zmd->nr_reserved_seq) {
+ list_add_tail(&zone->link, &zmd->reserved_seq_zones_list);
+ atomic_inc(&zmd->nr_reserved_seq_zones);
+ } else {
+ list_add_tail(&zone->link, &zmd->unmap_seq_list);
+ atomic_inc(&zmd->unmap_nr_seq);
+ }
+
+ wake_up_all(&zmd->free_wq);
+}
+
+/*
+ * Map a chunk to a zone.
+ * This must be called with the mapping lock held.
+ */
+void dmz_map_zone(struct dmz_metadata *zmd, struct dm_zone *dzone,
+ unsigned int chunk)
+{
+ /* Set the chunk mapping */
+ dmz_set_chunk_mapping(zmd, chunk, dmz_id(zmd, dzone),
+ DMZ_MAP_UNMAPPED);
+ dzone->chunk = chunk;
+ if (dmz_is_rnd(dzone))
+ list_add_tail(&dzone->link, &zmd->map_rnd_list);
+ else
+ list_add_tail(&dzone->link, &zmd->map_seq_list);
+}
+
+/*
+ * Unmap a zone.
+ * This must be called with the mapping lock held.
+ */
+void dmz_unmap_zone(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ unsigned int chunk = zone->chunk;
+ unsigned int dzone_id;
+
+ if (chunk == DMZ_MAP_UNMAPPED) {
+ /* Already unmapped */
+ return;
+ }
+
+ if (test_and_clear_bit(DMZ_BUF, &zone->flags)) {
+ /*
+ * Unmapping the chunk buffer zone: clear only
+ * the chunk buffer mapping
+ */
+ dzone_id = dmz_id(zmd, zone->bzone);
+ zone->bzone->bzone = NULL;
+ zone->bzone = NULL;
+
+ } else {
+ /*
+ * Unmapping the chunk data zone: the zone must
+ * not be buffered.
+ */
+ if (WARN_ON(zone->bzone)) {
+ zone->bzone->bzone = NULL;
+ zone->bzone = NULL;
+ }
+ dzone_id = DMZ_MAP_UNMAPPED;
+ }
+
+ dmz_set_chunk_mapping(zmd, chunk, dzone_id, DMZ_MAP_UNMAPPED);
+
+ zone->chunk = DMZ_MAP_UNMAPPED;
+ list_del_init(&zone->link);
+}
+
+/*
+ * Set @nr_bits bits in @bitmap starting from @bit.
+ * Return the number of bits changed from 0 to 1.
+ */
+static unsigned int dmz_set_bits(unsigned long *bitmap,
+ unsigned int bit, unsigned int nr_bits)
+{
+ unsigned long *addr;
+ unsigned int end = bit + nr_bits;
+ unsigned int n = 0;
+
+ while (bit < end) {
+ if (((bit & (BITS_PER_LONG - 1)) == 0) &&
+ ((end - bit) >= BITS_PER_LONG)) {
+ /* Try to set the whole word at once */
+ addr = bitmap + BIT_WORD(bit);
+ if (*addr == 0) {
+ *addr = ULONG_MAX;
+ n += BITS_PER_LONG;
+ bit += BITS_PER_LONG;
+ continue;
+ }
+ }
+
+ if (!test_and_set_bit(bit, bitmap))
+ n++;
+ bit++;
+ }
+
+ return n;
+}
+
+/*
+ * Get the bitmap block storing the bit for chunk_block in zone.
+ */
+static struct dmz_mblock *dmz_get_bitmap(struct dmz_metadata *zmd,
+ struct dm_zone *zone,
+ sector_t chunk_block)
+{
+ sector_t bitmap_block = 1 + zmd->nr_map_blocks +
+ (sector_t)(dmz_id(zmd, zone) * zmd->zone_nr_bitmap_blocks) +
+ (chunk_block >> DMZ_BLOCK_SHIFT_BITS);
+
+ return dmz_get_mblock(zmd, bitmap_block);
+}
+
+/*
+ * Copy the valid blocks bitmap of from_zone to the bitmap of to_zone.
+ */
+int dmz_copy_valid_blocks(struct dmz_metadata *zmd, struct dm_zone *from_zone,
+ struct dm_zone *to_zone)
+{
+ struct dmz_mblock *from_mblk, *to_mblk;
+ sector_t chunk_block = 0;
+
+ /* Get the zones bitmap blocks */
+ while (chunk_block < zmd->dev->zone_nr_blocks) {
+ from_mblk = dmz_get_bitmap(zmd, from_zone, chunk_block);
+ if (IS_ERR(from_mblk))
+ return PTR_ERR(from_mblk);
+ to_mblk = dmz_get_bitmap(zmd, to_zone, chunk_block);
+ if (IS_ERR(to_mblk)) {
+ dmz_release_mblock(zmd, from_mblk);
+ return PTR_ERR(to_mblk);
+ }
+
+ memcpy(to_mblk->data, from_mblk->data, DMZ_BLOCK_SIZE);
+ dmz_dirty_mblock(zmd, to_mblk);
+
+ dmz_release_mblock(zmd, to_mblk);
+ dmz_release_mblock(zmd, from_mblk);
+
+ chunk_block += DMZ_BLOCK_SIZE_BITS;
+ }
+
+ to_zone->weight = from_zone->weight;
+
+ return 0;
+}
+
+/*
+ * Merge the valid blocks bitmap of from_zone into the bitmap of to_zone,
+ * starting from chunk_block.
+ */
+int dmz_merge_valid_blocks(struct dmz_metadata *zmd, struct dm_zone *from_zone,
+ struct dm_zone *to_zone, sector_t chunk_block)
+{
+ unsigned int nr_blocks;
+ int ret;
+
+ /* Get the zones bitmap blocks */
+ while (chunk_block < zmd->dev->zone_nr_blocks) {
+ /* Get a valid region from the source zone */
+ ret = dmz_first_valid_block(zmd, from_zone, &chunk_block);
+ if (ret <= 0)
+ return ret;
+
+ nr_blocks = ret;
+ ret = dmz_validate_blocks(zmd, to_zone, chunk_block, nr_blocks);
+ if (ret)
+ return ret;
+
+ chunk_block += nr_blocks;
+ }
+
+ return 0;
+}
+
+/*
+ * Validate all the blocks in the range [block..block+nr_blocks-1].
+ */
+int dmz_validate_blocks(struct dmz_metadata *zmd, struct dm_zone *zone,
+ sector_t chunk_block, unsigned int nr_blocks)
+{
+ unsigned int count, bit, nr_bits;
+ unsigned int zone_nr_blocks = zmd->dev->zone_nr_blocks;
+ struct dmz_mblock *mblk;
+ unsigned int n = 0;
+
+ dmz_dev_debug(zmd->dev, "=> VALIDATE zone %u, block %llu, %u blocks",
+ dmz_id(zmd, zone), (unsigned long long)chunk_block,
+ nr_blocks);
+
+ WARN_ON(chunk_block + nr_blocks > zone_nr_blocks);
+
+ while (nr_blocks) {
+ /* Get bitmap block */
+ mblk = dmz_get_bitmap(zmd, zone, chunk_block);
+ if (IS_ERR(mblk))
+ return PTR_ERR(mblk);
+
+ /* Set bits */
+ bit = chunk_block & DMZ_BLOCK_MASK_BITS;
+ nr_bits = min(nr_blocks, DMZ_BLOCK_SIZE_BITS - bit);
+
+ count = dmz_set_bits((unsigned long *)mblk->data, bit, nr_bits);
+ if (count) {
+ dmz_dirty_mblock(zmd, mblk);
+ n += count;
+ }
+ dmz_release_mblock(zmd, mblk);
+
+ nr_blocks -= nr_bits;
+ chunk_block += nr_bits;
+ }
+
+ if (likely(zone->weight + n <= zone_nr_blocks))
+ zone->weight += n;
+ else {
+ dmz_dev_warn(zmd->dev, "Zone %u: weight %u should be <= %u",
+ dmz_id(zmd, zone), zone->weight,
+ zone_nr_blocks - n);
+ zone->weight = zone_nr_blocks;
+ }
+
+ return 0;
+}
+
+/*
+ * Clear nr_bits bits in bitmap starting from bit.
+ * Return the number of bits cleared.
+ */
+static int dmz_clear_bits(unsigned long *bitmap, int bit, int nr_bits)
+{
+ unsigned long *addr;
+ int end = bit + nr_bits;
+ int n = 0;
+
+ while (bit < end) {
+ if (((bit & (BITS_PER_LONG - 1)) == 0) &&
+ ((end - bit) >= BITS_PER_LONG)) {
+ /* Try to clear whole word at once */
+ addr = bitmap + BIT_WORD(bit);
+ if (*addr == ULONG_MAX) {
+ *addr = 0;
+ n += BITS_PER_LONG;
+ bit += BITS_PER_LONG;
+ continue;
+ }
+ }
+
+ if (test_and_clear_bit(bit, bitmap))
+ n++;
+ bit++;
+ }
+
+ return n;
+}
+
+/*
+ * Invalidate all the blocks in the range [block..block+nr_blocks-1].
+ */
+int dmz_invalidate_blocks(struct dmz_metadata *zmd, struct dm_zone *zone,
+ sector_t chunk_block, unsigned int nr_blocks)
+{
+ unsigned int count, bit, nr_bits;
+ struct dmz_mblock *mblk;
+ unsigned int n = 0;
+
+ dmz_dev_debug(zmd->dev, "=> INVALIDATE zone %u, block %llu, %u blocks",
+ dmz_id(zmd, zone), (u64)chunk_block, nr_blocks);
+
+ WARN_ON(chunk_block + nr_blocks > zmd->dev->zone_nr_blocks);
+
+ while (nr_blocks) {
+ /* Get bitmap block */
+ mblk = dmz_get_bitmap(zmd, zone, chunk_block);
+ if (IS_ERR(mblk))
+ return PTR_ERR(mblk);
+
+ /* Clear bits */
+ bit = chunk_block & DMZ_BLOCK_MASK_BITS;
+ nr_bits = min(nr_blocks, DMZ_BLOCK_SIZE_BITS - bit);
+
+ count = dmz_clear_bits((unsigned long *)mblk->data,
+ bit, nr_bits);
+ if (count) {
+ dmz_dirty_mblock(zmd, mblk);
+ n += count;
+ }
+ dmz_release_mblock(zmd, mblk);
+
+ nr_blocks -= nr_bits;
+ chunk_block += nr_bits;
+ }
+
+ if (zone->weight >= n)
+ zone->weight -= n;
+ else {
+ dmz_dev_warn(zmd->dev, "Zone %u: weight %u should be >= %u",
+ dmz_id(zmd, zone), zone->weight, n);
+ zone->weight = 0;
+ }
+
+ return 0;
+}
+
+/*
+ * Get a block bit value.
+ */
+static int dmz_test_block(struct dmz_metadata *zmd, struct dm_zone *zone,
+ sector_t chunk_block)
+{
+ struct dmz_mblock *mblk;
+ int ret;
+
+ WARN_ON(chunk_block >= zmd->dev->zone_nr_blocks);
+
+ /* Get bitmap block */
+ mblk = dmz_get_bitmap(zmd, zone, chunk_block);
+ if (IS_ERR(mblk))
+ return PTR_ERR(mblk);
+
+ /* Get offset */
+ ret = test_bit(chunk_block & DMZ_BLOCK_MASK_BITS,
+ (unsigned long *) mblk->data) != 0;
+
+ dmz_release_mblock(zmd, mblk);
+
+ return ret;
+}
+
+/*
+ * Return the number of blocks from chunk_block to the first block with a bit
+ * value specified by set. Search at most nr_blocks blocks from chunk_block.
+ */
+static int dmz_to_next_set_block(struct dmz_metadata *zmd, struct dm_zone *zone,
+ sector_t chunk_block, unsigned int nr_blocks,
+ int set)
+{
+ struct dmz_mblock *mblk;
+ unsigned int bit, set_bit, nr_bits;
+ unsigned long *bitmap;
+ int n = 0;
+
+ WARN_ON(chunk_block + nr_blocks > zmd->dev->zone_nr_blocks);
+
+ while (nr_blocks) {
+ /* Get bitmap block */
+ mblk = dmz_get_bitmap(zmd, zone, chunk_block);
+ if (IS_ERR(mblk))
+ return PTR_ERR(mblk);
+
+ /* Get offset */
+ bitmap = (unsigned long *) mblk->data;
+ bit = chunk_block & DMZ_BLOCK_MASK_BITS;
+ nr_bits = min(nr_blocks, DMZ_BLOCK_SIZE_BITS - bit);
+ if (set)
+ set_bit = find_next_bit(bitmap, DMZ_BLOCK_SIZE_BITS, bit);
+ else
+ set_bit = find_next_zero_bit(bitmap, DMZ_BLOCK_SIZE_BITS, bit);
+ dmz_release_mblock(zmd, mblk);
+
+ n += set_bit - bit;
+ if (set_bit < DMZ_BLOCK_SIZE_BITS)
+ break;
+
+ nr_blocks -= nr_bits;
+ chunk_block += nr_bits;
+ }
+
+ return n;
+}
+
+/*
+ * Test if chunk_block is valid. If it is, the number of consecutive
+ * valid blocks from chunk_block will be returned.
+ */
+int dmz_block_valid(struct dmz_metadata *zmd, struct dm_zone *zone,
+ sector_t chunk_block)
+{
+ int valid;
+
+ valid = dmz_test_block(zmd, zone, chunk_block);
+ if (valid <= 0)
+ return valid;
+
+ /* The block is valid: get the number of valid blocks from block */
+ return dmz_to_next_set_block(zmd, zone, chunk_block,
+ zmd->dev->zone_nr_blocks - chunk_block, 0);
+}
+
+/*
+ * Find the first valid block from @chunk_block in @zone.
+ * If such a block is found, its number is returned using
+ * @chunk_block and the total number of valid blocks from @chunk_block
+ * is returned.
+ */
+int dmz_first_valid_block(struct dmz_metadata *zmd, struct dm_zone *zone,
+ sector_t *chunk_block)
+{
+ sector_t start_block = *chunk_block;
+ int ret;
+
+ ret = dmz_to_next_set_block(zmd, zone, start_block,
+ zmd->dev->zone_nr_blocks - start_block, 1);
+ if (ret < 0)
+ return ret;
+
+ start_block += ret;
+ *chunk_block = start_block;
+
+ return dmz_to_next_set_block(zmd, zone, start_block,
+ zmd->dev->zone_nr_blocks - start_block, 0);
+}
+
+/*
+ * Count the number of bits set starting from bit up to bit + nr_bits - 1.
+ */
+static int dmz_count_bits(void *bitmap, int bit, int nr_bits)
+{
+ unsigned long *addr;
+ int end = bit + nr_bits;
+ int n = 0;
+
+ while (bit < end) {
+ if (((bit & (BITS_PER_LONG - 1)) == 0) &&
+ ((end - bit) >= BITS_PER_LONG)) {
+ addr = (unsigned long *)bitmap + BIT_WORD(bit);
+ if (*addr == ULONG_MAX) {
+ n += BITS_PER_LONG;
+ bit += BITS_PER_LONG;
+ continue;
+ }
+ }
+
+ if (test_bit(bit, bitmap))
+ n++;
+ bit++;
+ }
+
+ return n;
+}
+
+/*
+ * Get a zone weight.
+ */
+static void dmz_get_zone_weight(struct dmz_metadata *zmd, struct dm_zone *zone)
+{
+ struct dmz_mblock *mblk;
+ sector_t chunk_block = 0;
+ unsigned int bit, nr_bits;
+ unsigned int nr_blocks = zmd->dev->zone_nr_blocks;
+ void *bitmap;
+ int n = 0;
+
+ while (nr_blocks) {
+ /* Get bitmap block */
+ mblk = dmz_get_bitmap(zmd, zone, chunk_block);
+ if (IS_ERR(mblk)) {
+ n = 0;
+ break;
+ }
+
+ /* Count bits in this block */
+ bitmap = mblk->data;
+ bit = chunk_block & DMZ_BLOCK_MASK_BITS;
+ nr_bits = min(nr_blocks, DMZ_BLOCK_SIZE_BITS - bit);
+ n += dmz_count_bits(bitmap, bit, nr_bits);
+
+ dmz_release_mblock(zmd, mblk);
+
+ nr_blocks -= nr_bits;
+ chunk_block += nr_bits;
+ }
+
+ zone->weight = n;
+}
+
+/*
+ * Cleanup the zoned metadata resources.
+ */
+static void dmz_cleanup_metadata(struct dmz_metadata *zmd)
+{
+ struct rb_root *root;
+ struct dmz_mblock *mblk, *next;
+ int i;
+
+ /* Release zone mapping resources */
+ if (zmd->map_mblk) {
+ for (i = 0; i < zmd->nr_map_blocks; i++)
+ dmz_release_mblock(zmd, zmd->map_mblk[i]);
+ kfree(zmd->map_mblk);
+ zmd->map_mblk = NULL;
+ }
+
+ /* Release super blocks */
+ for (i = 0; i < 2; i++) {
+ if (zmd->sb[i].mblk) {
+ dmz_free_mblock(zmd, zmd->sb[i].mblk);
+ zmd->sb[i].mblk = NULL;
+ }
+ }
+
+ /* Free cached blocks */
+ while (!list_empty(&zmd->mblk_dirty_list)) {
+ mblk = list_first_entry(&zmd->mblk_dirty_list,
+ struct dmz_mblock, link);
+ dmz_dev_warn(zmd->dev, "mblock %llu still in dirty list (ref %u)",
+ (u64)mblk->no, atomic_read(&mblk->ref));
+ list_del_init(&mblk->link);
+ rb_erase(&mblk->node, &zmd->mblk_rbtree);
+ dmz_free_mblock(zmd, mblk);
+ }
+
+ while (!list_empty(&zmd->mblk_lru_list)) {
+ mblk = list_first_entry(&zmd->mblk_lru_list,
+ struct dmz_mblock, link);
+ list_del_init(&mblk->link);
+ rb_erase(&mblk->node, &zmd->mblk_rbtree);
+ dmz_free_mblock(zmd, mblk);
+ }
+
+ /* Sanity checks: the mblock rbtree should now be empty */
+ root = &zmd->mblk_rbtree;
+ rbtree_postorder_for_each_entry_safe(mblk, next, root, node) {
+ dmz_dev_warn(zmd->dev, "mblock %llu ref %u still in rbtree",
+ (u64)mblk->no, atomic_read(&mblk->ref));
+ atomic_set(&mblk->ref, 0);
+ dmz_free_mblock(zmd, mblk);
+ }
+
+ /* Free the zone descriptors */
+ dmz_drop_zones(zmd);
+}
+
+/*
+ * Initialize the zoned metadata.
+ */
+int dmz_ctr_metadata(struct dmz_dev *dev, struct dmz_metadata **metadata)
+{
+ struct dmz_metadata *zmd;
+ unsigned int i, zid;
+ struct dm_zone *zone;
+ int ret;
+
+ zmd = kzalloc(sizeof(struct dmz_metadata), GFP_KERNEL);
+ if (!zmd)
+ return -ENOMEM;
+
+ zmd->dev = dev;
+ zmd->mblk_rbtree = RB_ROOT;
+ init_rwsem(&zmd->mblk_sem);
+ mutex_init(&zmd->mblk_flush_lock);
+ spin_lock_init(&zmd->mblk_lock);
+ INIT_LIST_HEAD(&zmd->mblk_lru_list);
+ INIT_LIST_HEAD(&zmd->mblk_dirty_list);
+
+ mutex_init(&zmd->map_lock);
+ atomic_set(&zmd->unmap_nr_rnd, 0);
+ INIT_LIST_HEAD(&zmd->unmap_rnd_list);
+ INIT_LIST_HEAD(&zmd->map_rnd_list);
+
+ atomic_set(&zmd->unmap_nr_seq, 0);
+ INIT_LIST_HEAD(&zmd->unmap_seq_list);
+ INIT_LIST_HEAD(&zmd->map_seq_list);
+
+ atomic_set(&zmd->nr_reserved_seq_zones, 0);
+ INIT_LIST_HEAD(&zmd->reserved_seq_zones_list);
+
+ init_waitqueue_head(&zmd->free_wq);
+
+ /* Initialize zone descriptors */
+ ret = dmz_init_zones(zmd);
+ if (ret)
+ goto err;
+
+ /* Get super block */
+ ret = dmz_load_sb(zmd);
+ if (ret)
+ goto err;
+
+ /* Set metadata zones starting from sb_zone */
+ zid = dmz_id(zmd, zmd->sb_zone);
+ for (i = 0; i < zmd->nr_meta_zones << 1; i++) {
+ zone = dmz_get(zmd, zid + i);
+ if (!dmz_is_rnd(zone))
+ goto err;
+ set_bit(DMZ_META, &zone->flags);
+ }
+
+ /* Load mapping table */
+ ret = dmz_load_mapping(zmd);
+ if (ret)
+ goto err;
+
+ /*
+ * Cache size boundaries: allow at least 2 super blocks, the chunk map
+ * blocks and enough blocks to be able to cache the bitmap blocks of
+ * up to 16 zones when idle (min_nr_mblks). Otherwise, if busy, allow
+ * the cache to add 512 more metadata blocks.
+ */
+ zmd->min_nr_mblks = 2 + zmd->nr_map_blocks + zmd->zone_nr_bitmap_blocks * 16;
+ zmd->max_nr_mblks = zmd->min_nr_mblks + 512;
+ zmd->mblk_shrinker.count_objects = dmz_mblock_shrinker_count;
+ zmd->mblk_shrinker.scan_objects = dmz_mblock_shrinker_scan;
+ zmd->mblk_shrinker.seeks = DEFAULT_SEEKS;
+
+ /* Metadata cache shrinker */
+ ret = register_shrinker(&zmd->mblk_shrinker);
+ if (ret) {
+ dmz_dev_err(dev, "Register metadata cache shrinker failed");
+ goto err;
+ }
+
+ dmz_dev_info(dev, "Host-%s zoned block device",
+ bdev_zoned_model(dev->bdev) == BLK_ZONED_HA ?
+ "aware" : "managed");
+ dmz_dev_info(dev, " %llu 512-byte logical sectors",
+ (u64)dev->capacity);
+ dmz_dev_info(dev, " %u zones of %llu 512-byte logical sectors",
+ dev->nr_zones, (u64)dev->zone_nr_sectors);
+ dmz_dev_info(dev, " %u metadata zones",
+ zmd->nr_meta_zones * 2);
+ dmz_dev_info(dev, " %u data zones for %u chunks",
+ zmd->nr_data_zones, zmd->nr_chunks);
+ dmz_dev_info(dev, " %u random zones (%u unmapped)",
+ zmd->nr_rnd, atomic_read(&zmd->unmap_nr_rnd));
+ dmz_dev_info(dev, " %u sequential zones (%u unmapped)",
+ zmd->nr_seq, atomic_read(&zmd->unmap_nr_seq));
+ dmz_dev_info(dev, " %u reserved sequential data zones",
+ zmd->nr_reserved_seq);
+
+ dmz_dev_debug(dev, "Format:");
+ dmz_dev_debug(dev, "%u metadata blocks per set (%u max cache)",
+ zmd->nr_meta_blocks, zmd->max_nr_mblks);
+ dmz_dev_debug(dev, " %u data zone mapping blocks",
+ zmd->nr_map_blocks);
+ dmz_dev_debug(dev, " %u bitmap blocks",
+ zmd->nr_bitmap_blocks);
+
+ *metadata = zmd;
+
+ return 0;
+err:
+ dmz_cleanup_metadata(zmd);
+ kfree(zmd);
+ *metadata = NULL;
+
+ return ret;
+}
+
+/*
+ * Cleanup the zoned metadata resources.
+ */
+void dmz_dtr_metadata(struct dmz_metadata *zmd)
+{
+ unregister_shrinker(&zmd->mblk_shrinker);
+ dmz_cleanup_metadata(zmd);
+ kfree(zmd);
+}
+
+/*
+ * Check zone information on resume.
+ */
+int dmz_resume_metadata(struct dmz_metadata *zmd)
+{
+ struct dmz_dev *dev = zmd->dev;
+ struct dm_zone *zone;
+ sector_t wp_block;
+ unsigned int i;
+ int ret;
+
+ /* Check zones */
+ for (i = 0; i < dev->nr_zones; i++) {
+ zone = dmz_get(zmd, i);
+ if (!zone) {
+ dmz_dev_err(dev, "Unable to get zone %u", i);
+ return -EIO;
+ }
+
+ wp_block = zone->wp_block;
+
+ ret = dmz_update_zone(zmd, zone);
+ if (ret) {
+ dmz_dev_err(dev, "Broken zone %u", i);
+ return ret;
+ }
+
+ if (dmz_is_offline(zone)) {
+ dmz_dev_warn(dev, "Zone %u is offline", i);
+ continue;
+ }
+
+ /* Check write pointer */
+ if (!dmz_is_seq(zone))
+ zone->wp_block = 0;
+ else if (zone->wp_block != wp_block) {
+ dmz_dev_err(dev, "Zone %u: Invalid wp (%llu / %llu)",
+ i, (u64)zone->wp_block, (u64)wp_block);
+ zone->wp_block = wp_block;
+ dmz_invalidate_blocks(zmd, zone, zone->wp_block,
+ dev->zone_nr_blocks - zone->wp_block);
+ }
+ }
+
+ return 0;
+}
