Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-block

Pull block layer updates from Jens Axboe:
 "This is the first pull request for 4.14, containing most of the code
  changes. It's a quiet series this round, which I think we needed after
  the churn of the last few series. This contains:

   - Fix for a registration race in loop, from Anton Volkov.

   - Overflow complaint fix from Arnd for DAC960.

   - Series of drbd changes from the usual suspects.

   - Conversion of the stec/skd driver to blk-mq. From Bart.

   - A few BFQ improvements/fixes from Paolo.

   - CFQ improvement from Ritesh, allowing idling for group idle.

   - A few fixes found by Dan's smatch, courtesy of Dan.

   - A warning fixup for a race between changing the IO scheduler and
     device remova. From David Jeffery.

   - A few nbd fixes from Josef.

   - Support for cgroup info in blktrace, from Shaohua.

   - Also from Shaohua, new features in the null_blk driver to allow it
     to actually hold data, among other things.

   - Various corner cases and error handling fixes from Weiping Zhang.

   - Improvements to the IO stats tracking for blk-mq from me. Can
     drastically improve performance for fast devices and/or big
     machines.

   - Series from Christoph removing bi_bdev as being needed for IO
     submission, in preparation for nvme multipathing code.

   - Series from Bart, including various cleanups and fixes for switch
     fall through case complaints"

* 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits)
  kernfs: checking for IS_ERR() instead of NULL
  drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set
  drbd: Fix allyesconfig build, fix recent commit
  drbd: switch from kmalloc() to kmalloc_array()
  drbd: abort drbd_start_resync if there is no connection
  drbd: move global variables to drbd namespace and make some static
  drbd: rename "usermode_helper" to "drbd_usermode_helper"
  drbd: fix race between handshake and admin disconnect/down
  drbd: fix potential deadlock when trying to detach during handshake
  drbd: A single dot should be put into a sequence.
  drbd: fix rmmod cleanup, remove _all_ debugfs entries
  drbd: Use setup_timer() instead of init_timer() to simplify the code.
  drbd: fix potential get_ldev/put_ldev refcount imbalance during attach
  drbd: new disk-option disable-write-same
  drbd: Fix resource role for newly created resources in events2
  drbd: mark symbols static where possible
  drbd: Send P_NEG_ACK upon write error in protocol != C
  drbd: add explicit plugging when submitting batches
  drbd: change list_for_each_safe to while(list_first_entry_or_null)
  drbd: introduce drbd_recv_header_maybe_unplug
  ...

34 files changed, 265 insertions, 111 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9941dc8..bb715b2 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -223,7 +223,7 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter,
 	}
 
 	bio_init(&bio, vecs, nr_pages);
-	bio.bi_bdev = bdev;
+	bio_set_dev(&bio, bdev);
 	bio.bi_iter.bi_sector = pos >> 9;
 	bio.bi_write_hint = iocb->ki_hint;
 	bio.bi_private = current;
@@ -362,7 +362,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 
 	blk_start_plug(&plug);
 	for (;;) {
-		bio->bi_bdev = bdev;
+		bio_set_dev(bio, bdev);
 		bio->bi_iter.bi_sector = pos >> 9;
 		bio->bi_write_hint = iocb->ki_hint;
 		bio->bi_private = dio;
@@ -1451,6 +1451,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 		bdev->bd_disk = disk;
 		bdev->bd_queue = disk->queue;
 		bdev->bd_contains = bdev;
+		bdev->bd_partno = partno;
 
 		if (!partno) {
 			ret = -ENXIO;
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 11d37c9..fb07e3c 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -296,8 +296,7 @@ static void btrfsic_dev_state_hashtable_add(
 		struct btrfsic_dev_state *ds,
 		struct btrfsic_dev_state_hashtable *h);
 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
-static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
-		struct block_device *bdev,
+static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 		struct btrfsic_dev_state_hashtable *h);
 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
@@ -385,8 +384,7 @@ static int btrfsic_process_superblock_dev_mirror(
 		int superblock_mirror_num,
 		struct btrfsic_dev_state **selected_dev_state,
 		struct btrfs_super_block *selected_super);
-static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
-		struct block_device *bdev);
+static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev);
 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 					   u64 bytenr,
 					   struct btrfsic_dev_state *dev_state,
@@ -626,17 +624,15 @@ static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 	list_del(&ds->collision_resolving_node);
 }
 
-static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
-		struct block_device *bdev,
+static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 		struct btrfsic_dev_state_hashtable *h)
 {
 	const unsigned int hashval =
-	    (((unsigned int)((uintptr_t)bdev)) &
-	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
+		dev & (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1);
 	struct btrfsic_dev_state *ds;
 
 	list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
-		if (ds->bdev == bdev)
+		if (ds->bdev->bd_dev == dev)
 			return ds;
 	}
 
@@ -668,7 +664,7 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
 		if (!device->bdev || !device->name)
 			continue;
 
-		dev_state = btrfsic_dev_state_lookup(device->bdev);
+		dev_state = btrfsic_dev_state_lookup(device->bdev->bd_dev);
 		BUG_ON(NULL == dev_state);
 		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 			ret = btrfsic_process_superblock_dev_mirror(
@@ -1556,7 +1552,7 @@ static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 	}
 
 	device = multi->stripes[0].dev;
-	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
+	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev->bd_dev);
 	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
 	block_ctx_out->start = bytenr;
 	block_ctx_out->len = len;
@@ -1639,7 +1635,7 @@ static int btrfsic_read_block(struct btrfsic_state *state,
 		unsigned int j;
 
 		bio = btrfs_io_bio_alloc(num_pages - i);
-		bio->bi_bdev = block_ctx->dev->bdev;
+		bio_set_dev(bio, block_ctx->dev->bdev);
 		bio->bi_iter.bi_sector = dev_bytenr >> 9;
 		bio_set_op_attrs(bio, REQ_OP_READ, 0);
 
@@ -2654,7 +2650,7 @@ static struct btrfsic_block *btrfsic_block_lookup_or_add(
 			pr_info("btrfsic: error, kmalloc failed!\n");
 			return NULL;
 		}
-		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
+		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev->bd_dev);
 		if (NULL == dev_state) {
 			pr_info("btrfsic: error, lookup dev_state failed!\n");
 			btrfsic_block_free(block);
@@ -2734,10 +2730,9 @@ static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 	}
 }
 
-static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
-		struct block_device *bdev)
+static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev)
 {
-	return btrfsic_dev_state_hashtable_lookup(bdev,
+	return btrfsic_dev_state_hashtable_lookup(dev,
 						  &btrfsic_dev_state_hashtable);
 }
 
@@ -2751,7 +2746,7 @@ int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh)
 	mutex_lock(&btrfsic_mutex);
 	/* since btrfsic_submit_bh() might also be called before
 	 * btrfsic_mount(), this might return NULL */
-	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
+	dev_state = btrfsic_dev_state_lookup(bh->b_bdev->bd_dev);
 
 	/* Only called to write the superblock (incl. FLUSH/FUA) */
 	if (NULL != dev_state &&
@@ -2808,7 +2803,7 @@ static void __btrfsic_submit_bio(struct bio *bio)
 	mutex_lock(&btrfsic_mutex);
 	/* since btrfsic_submit_bio() is also called before
 	 * btrfsic_mount(), this might return NULL */
-	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
+	dev_state = btrfsic_dev_state_lookup(bio_dev(bio));
 	if (NULL != dev_state &&
 	    (bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
 		unsigned int i = 0;
@@ -2824,10 +2819,10 @@ static void __btrfsic_submit_bio(struct bio *bio)
 		bio_is_patched = 0;
 		if (dev_state->state->print_mask &
 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
-			pr_info("submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
+			pr_info("submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_disk=%p)\n",
 			       bio_op(bio), bio->bi_opf, segs,
 			       (unsigned long long)bio->bi_iter.bi_sector,
-			       dev_bytenr, bio->bi_bdev);
+			       dev_bytenr, bio->bi_disk);
 
 		mapped_datav = kmalloc_array(segs,
 					     sizeof(*mapped_datav), GFP_NOFS);
@@ -2856,8 +2851,8 @@ static void __btrfsic_submit_bio(struct bio *bio)
 	} else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
 		if (dev_state->state->print_mask &
 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
-			pr_info("submit_bio(rw=%d,0x%x FLUSH, bdev=%p)\n",
-			       bio_op(bio), bio->bi_opf, bio->bi_bdev);
+			pr_info("submit_bio(rw=%d,0x%x FLUSH, disk=%p)\n",
+			       bio_op(bio), bio->bi_opf, bio->bi_disk);
 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
 			if ((dev_state->state->print_mask &
 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
@@ -2998,7 +2993,7 @@ void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
 			continue;
 
 		ds = btrfsic_dev_state_hashtable_lookup(
-				device->bdev,
+				device->bdev->bd_dev,
 				&btrfsic_dev_state_hashtable);
 		if (NULL != ds) {
 			state = ds->state;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f45b61f..4f428a4 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3499,7 +3499,7 @@ static void write_dev_flush(struct btrfs_device *device)
 
 	bio_reset(bio);
 	bio->bi_end_io = btrfs_end_empty_barrier;
-	bio->bi_bdev = device->bdev;
+	bio_set_dev(bio, device->bdev);
 	bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH;
 	init_completion(&device->flush_wait);
 	bio->bi_private = &device->flush_wait;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0aff9b2..42b12a8 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2033,7 +2033,7 @@ int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
 		bio_put(bio);
 		return -EIO;
 	}
-	bio->bi_bdev = dev->bdev;
+	bio_set_dev(bio, dev->bdev);
 	bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
 	bio_add_page(bio, page, length, pg_offset);
 
@@ -2335,7 +2335,7 @@ struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
 	bio = btrfs_io_bio_alloc(1);
 	bio->bi_end_io = endio_func;
 	bio->bi_iter.bi_sector = failrec->logical >> 9;
-	bio->bi_bdev = fs_info->fs_devices->latest_bdev;
+	bio_set_dev(bio, fs_info->fs_devices->latest_bdev);
 	bio->bi_iter.bi_size = 0;
 	bio->bi_private = data;
 
@@ -2675,7 +2675,7 @@ struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_byte)
 	struct bio *bio;
 
 	bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, btrfs_bioset);
-	bio->bi_bdev = bdev;
+	bio_set_dev(bio, bdev);
 	bio->bi_iter.bi_sector = first_byte >> 9;
 	btrfs_io_bio_init(btrfs_io_bio(bio));
 	return bio;
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 2cf6ba4..24a6222 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1090,7 +1090,8 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
 		 */
 		if (last_end == disk_start && stripe->dev->bdev &&
 		    !last->bi_status &&
-		    last->bi_bdev == stripe->dev->bdev) {
+		    last->bi_disk == stripe->dev->bdev->bd_disk &&
+		    last->bi_partno == stripe->dev->bdev->bd_partno) {
 			ret = bio_add_page(last, page, PAGE_SIZE, 0);
 			if (ret == PAGE_SIZE)
 				return 0;
@@ -1100,7 +1101,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
 	/* put a new bio on the list */
 	bio = btrfs_io_bio_alloc(bio_max_len >> PAGE_SHIFT ?: 1);
 	bio->bi_iter.bi_size = 0;
-	bio->bi_bdev = stripe->dev->bdev;
+	bio_set_dev(bio, stripe->dev->bdev);
 	bio->bi_iter.bi_sector = disk_start >> 9;
 
 	bio_add_page(bio, page, PAGE_SIZE, 0);
@@ -1347,7 +1348,8 @@ static int find_bio_stripe(struct btrfs_raid_bio *rbio,
 		stripe_start = stripe->physical;
 		if (physical >= stripe_start &&
 		    physical < stripe_start + rbio->stripe_len &&
-		    bio->bi_bdev == stripe->dev->bdev) {
+		    bio->bi_disk == stripe->dev->bdev->bd_disk &&
+		    bio->bi_partno == stripe->dev->bdev->bd_partno) {
 			return i;
 		}
 	}
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 6f1e4c9..b0b71e8 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1738,7 +1738,7 @@ static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
 
 		WARN_ON(!page->page);
 		bio = btrfs_io_bio_alloc(1);
-		bio->bi_bdev = page->dev->bdev;
+		bio_set_dev(bio, page->dev->bdev);
 
 		bio_add_page(bio, page->page, PAGE_SIZE, 0);
 		if (!retry_failed_mirror && scrub_is_page_on_raid56(page)) {
@@ -1826,7 +1826,7 @@ static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
 		}
 
 		bio = btrfs_io_bio_alloc(1);
-		bio->bi_bdev = page_bad->dev->bdev;
+		bio_set_dev(bio, page_bad->dev->bdev);
 		bio->bi_iter.bi_sector = page_bad->physical >> 9;
 		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 
@@ -1921,7 +1921,7 @@ again:
 
 		bio->bi_private = sbio;
 		bio->bi_end_io = scrub_wr_bio_end_io;
-		bio->bi_bdev = sbio->dev->bdev;
+		bio_set_dev(bio, sbio->dev->bdev);
 		bio->bi_iter.bi_sector = sbio->physical >> 9;
 		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 		sbio->status = 0;
@@ -1964,7 +1964,7 @@ static void scrub_wr_submit(struct scrub_ctx *sctx)
 
 	sbio = sctx->wr_curr_bio;
 	sctx->wr_curr_bio = NULL;
-	WARN_ON(!sbio->bio->bi_bdev);
+	WARN_ON(!sbio->bio->bi_disk);
 	scrub_pending_bio_inc(sctx);
 	/* process all writes in a single worker thread. Then the block layer
 	 * orders the requests before sending them to the driver which
@@ -2321,7 +2321,7 @@ again:
 
 		bio->bi_private = sbio;
 		bio->bi_end_io = scrub_bio_end_io;
-		bio->bi_bdev = sbio->dev->bdev;
+		bio_set_dev(bio, sbio->dev->bdev);
 		bio->bi_iter.bi_sector = sbio->physical >> 9;
 		bio_set_op_attrs(bio, REQ_OP_READ, 0);
 		sbio->status = 0;
@@ -4627,7 +4627,7 @@ static int write_page_nocow(struct scrub_ctx *sctx,
 	bio = btrfs_io_bio_alloc(1);
 	bio->bi_iter.bi_size = 0;
 	bio->bi_iter.bi_sector = physical_for_dev_replace >> 9;
-	bio->bi_bdev = dev->bdev;
+	bio_set_dev(bio, dev->bdev);
 	bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
 	ret = bio_add_page(bio, page, PAGE_SIZE, 0);
 	if (ret != PAGE_SIZE) {
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index bd679bc..002aa31 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6188,7 +6188,7 @@ static void submit_stripe_bio(struct btrfs_bio *bbio, struct bio *bio,
 		rcu_read_unlock();
 	}
 #endif
-	bio->bi_bdev = dev->bdev;
+	bio_set_dev(bio, dev->bdev);
 
 	btrfs_bio_counter_inc_noblocked(fs_info);
 
diff --git a/fs/buffer.c b/fs/buffer.c
index 50da0e1..170df85 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3056,7 +3056,7 @@ void guard_bio_eod(int op, struct bio *bio)
 	struct bio_vec *bvec = &bio->bi_io_vec[bio->bi_vcnt - 1];
 	unsigned truncated_bytes;
 
-	maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;
+	maxsector = get_capacity(bio->bi_disk);
 	if (!maxsector)
 		return;
 
@@ -3115,7 +3115,7 @@ static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
 	}
 
 	bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
-	bio->bi_bdev = bh->b_bdev;
+	bio_set_dev(bio, bh->b_bdev);
 	bio->bi_write_hint = write_hint;
 
 	bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index 6181e95..483784d 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -115,7 +115,7 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 			err = -ENOMEM;
 			goto errout;
 		}
-		bio->bi_bdev = inode->i_sb->s_bdev;
+		bio_set_dev(bio, inode->i_sb->s_bdev);
 		bio->bi_iter.bi_sector =
 			pblk << (inode->i_sb->s_blocksize_bits - 9);
 		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 08cf278..5fa2211 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -111,7 +111,7 @@ struct dio {
 	int op;
 	int op_flags;
 	blk_qc_t bio_cookie;
-	struct block_device *bio_bdev;
+	struct gendisk *bio_disk;
 	struct inode *inode;
 	loff_t i_size;			/* i_size when submitted */
 	dio_iodone_t *end_io;		/* IO completion function */
@@ -377,7 +377,7 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
 	 */
 	bio = bio_alloc(GFP_KERNEL, nr_vecs);
 
-	bio->bi_bdev = bdev;
+	bio_set_dev(bio, bdev);
 	bio->bi_iter.bi_sector = first_sector;
 	bio_set_op_attrs(bio, dio->op, dio->op_flags);
 	if (dio->is_async)
@@ -412,7 +412,7 @@ static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
 	if (dio->is_async && dio->op == REQ_OP_READ && dio->should_dirty)
 		bio_set_pages_dirty(bio);
 
-	dio->bio_bdev = bio->bi_bdev;
+	dio->bio_disk = bio->bi_disk;
 
 	if (sdio->submit_io) {
 		sdio->submit_io(bio, dio->inode, sdio->logical_offset_in_bio);
@@ -458,7 +458,7 @@ static struct bio *dio_await_one(struct dio *dio)
 		dio->waiter = current;
 		spin_unlock_irqrestore(&dio->bio_lock, flags);
 		if (!(dio->iocb->ki_flags & IOCB_HIPRI) ||
-		    !blk_mq_poll(bdev_get_queue(dio->bio_bdev), dio->bio_cookie))
+		    !blk_mq_poll(dio->bio_disk->queue, dio->bio_cookie))
 			io_schedule();
 		/* wake up sets us TASK_RUNNING */
 		spin_lock_irqsave(&dio->bio_lock, flags);
diff --git a/fs/exofs/ore.c b/fs/exofs/ore.c
index 8bb7280..3c6a9c1 100644
--- a/fs/exofs/ore.c
+++ b/fs/exofs/ore.c
@@ -869,7 +869,7 @@ static int _write_mirror(struct ore_io_state *ios, int cur_comp)
 					goto out;
 				}
 
-				bio->bi_bdev = NULL;
+				bio->bi_disk = NULL;
 				bio->bi_next = NULL;
 				per_dev->offset = master_dev->offset;
 				per_dev->length = master_dev->length;
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index c2fce44..55ad7dd 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -300,7 +300,7 @@ static void ext4_end_bio(struct bio *bio)
 	char b[BDEVNAME_SIZE];
 
 	if (WARN_ONCE(!io_end, "io_end is NULL: %s: sector %Lu len %u err %d\n",
-		      bdevname(bio->bi_bdev, b),
+		      bio_devname(bio, b),
 		      (long long) bio->bi_iter.bi_sector,
 		      (unsigned) bio_sectors(bio),
 		      bio->bi_status)) {
@@ -375,7 +375,7 @@ static int io_submit_init_bio(struct ext4_io_submit *io,
 		return -ENOMEM;
 	wbc_init_bio(io->io_wbc, bio);
 	bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
-	bio->bi_bdev = bh->b_bdev;
+	bio_set_dev(bio, bh->b_bdev);
 	bio->bi_end_io = ext4_end_bio;
 	bio->bi_private = ext4_get_io_end(io->io_end);
 	io->io_bio = bio;
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index 40a5497..04c9064 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -254,7 +254,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
 					fscrypt_release_ctx(ctx);
 				goto set_error_page;
 			}
-			bio->bi_bdev = bdev;
+			bio_set_dev(bio, bdev);
 			bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
 			bio->bi_end_io = mpage_end_io;
 			bio->bi_private = ctx;
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 87c1f41..a791aac 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -142,7 +142,7 @@ struct block_device *f2fs_target_device(struct f2fs_sb_info *sbi,
 		}
 	}
 	if (bio) {
-		bio->bi_bdev = bdev;
+		bio_set_dev(bio, bdev);
 		bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(blk_addr);
 	}
 	return bdev;
@@ -161,7 +161,8 @@ int f2fs_target_device_index(struct f2fs_sb_info *sbi, block_t blkaddr)
 static bool __same_bdev(struct f2fs_sb_info *sbi,
 				block_t blk_addr, struct bio *bio)
 {
-	return f2fs_target_device(sbi, blk_addr, NULL) == bio->bi_bdev;
+	struct block_device *b = f2fs_target_device(sbi, blk_addr, NULL);
+	return bio->bi_disk == b->bd_disk && bio->bi_partno == b->bd_partno;
 }
 
 /*
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index f964b68..6f8fc4a 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -447,7 +447,7 @@ static int __submit_flush_wait(struct f2fs_sb_info *sbi,
 	int ret;
 
 	bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH;
-	bio->bi_bdev = bdev;
+	bio_set_dev(bio, bdev);
 	ret = submit_bio_wait(bio);
 	bio_put(bio);
 
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 7dabbe7..c8ff7b7 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -268,7 +268,7 @@ static struct bio *gfs2_log_alloc_bio(struct gfs2_sbd *sdp, u64 blkno)
 
 	bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
 	bio->bi_iter.bi_sector = blkno * (sb->s_blocksize >> 9);
-	bio->bi_bdev = sb->s_bdev;
+	bio_set_dev(bio, sb->s_bdev);
 	bio->bi_end_io = gfs2_end_log_write;
 	bio->bi_private = sdp;
 
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 61ef6c9..52de103 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -221,7 +221,7 @@ static void gfs2_submit_bhs(int op, int op_flags, struct buffer_head *bhs[],
 
 		bio = bio_alloc(GFP_NOIO, num);
 		bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
-		bio->bi_bdev = bh->b_bdev;
+		bio_set_dev(bio, bh->b_bdev);
 		while (num > 0) {
 			bh = *bhs;
 			if (!bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh))) {
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index c0a4b37..8459358 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -242,7 +242,7 @@ static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector, int silent)
 
 	bio = bio_alloc(GFP_NOFS, 1);
 	bio->bi_iter.bi_sector = sector * (sb->s_blocksize >> 9);
-	bio->bi_bdev = sb->s_bdev;
+	bio_set_dev(bio, sb->s_bdev);
 	bio_add_page(bio, page, PAGE_SIZE, 0);
 
 	bio->bi_end_io = end_bio_io_page;
diff --git a/fs/hfsplus/wrapper.c b/fs/hfsplus/wrapper.c
index e254fa0..10032b9 100644
--- a/fs/hfsplus/wrapper.c
+++ b/fs/hfsplus/wrapper.c
@@ -65,7 +65,7 @@ int hfsplus_submit_bio(struct super_block *sb, sector_t sector,
 
 	bio = bio_alloc(GFP_NOIO, 1);
 	bio->bi_iter.bi_sector = sector;
-	bio->bi_bdev = sb->s_bdev;
+	bio_set_dev(bio, sb->s_bdev);
 	bio_set_op_attrs(bio, op, op_flags);
 
 	if (op != WRITE && data)
diff --git a/fs/iomap.c b/fs/iomap.c
index 8554a8d..269b24a 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -805,7 +805,7 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
 	struct bio *bio;
 
 	bio = bio_alloc(GFP_KERNEL, 1);
-	bio->bi_bdev = iomap->bdev;
+	bio_set_dev(bio, iomap->bdev);
 	bio->bi_iter.bi_sector =
 		iomap->blkno + ((pos - iomap->offset) >> 9);
 	bio->bi_private = dio;
@@ -884,7 +884,7 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
 			return 0;
 
 		bio = bio_alloc(GFP_KERNEL, nr_pages);
-		bio->bi_bdev = iomap->bdev;
+		bio_set_dev(bio, iomap->bdev);
 		bio->bi_iter.bi_sector =
 			iomap->blkno + ((pos - iomap->offset) >> 9);
 		bio->bi_write_hint = dio->iocb->ki_hint;
diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index a21f0e9..0e5d412 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1995,7 +1995,7 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 	bio = bio_alloc(GFP_NOFS, 1);
 
 	bio->bi_iter.bi_sector = bp->l_blkno << (log->l2bsize - 9);
-	bio->bi_bdev = log->bdev;
+	bio_set_dev(bio, log->bdev);
 
 	bio_add_page(bio, bp->l_page, LOGPSIZE, bp->l_offset);
 	BUG_ON(bio->bi_iter.bi_size != LOGPSIZE);
@@ -2139,7 +2139,7 @@ static void lbmStartIO(struct lbuf * bp)
 
 	bio = bio_alloc(GFP_NOFS, 1);
 	bio->bi_iter.bi_sector = bp->l_blkno << (log->l2bsize - 9);
-	bio->bi_bdev = log->bdev;
+	bio_set_dev(bio, log->bdev);
 
 	bio_add_page(bio, bp->l_page, LOGPSIZE, bp->l_offset);
 	BUG_ON(bio->bi_iter.bi_size != LOGPSIZE);
diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 65120a4..1c4b9ad 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -430,7 +430,7 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 		len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
 
 		bio = bio_alloc(GFP_NOFS, 1);
-		bio->bi_bdev = inode->i_sb->s_bdev;
+		bio_set_dev(bio, inode->i_sb->s_bdev);
 		bio->bi_iter.bi_sector = pblock << (inode->i_blkbits - 9);
 		bio->bi_end_io = metapage_write_end_io;
 		bio->bi_private = page;
@@ -510,7 +510,7 @@ static int metapage_readpage(struct file *fp, struct page *page)
 				submit_bio(bio);
 
 			bio = bio_alloc(GFP_NOFS, 1);
-			bio->bi_bdev = inode->i_sb->s_bdev;
+			bio_set_dev(bio, inode->i_sb->s_bdev);
 			bio->bi_iter.bi_sector =
 				pblock << (inode->i_blkbits - 9);
 			bio->bi_end_io = metapage_read_end_io;
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index db5900aaa..89d1dc1 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -21,6 +21,7 @@
 DEFINE_MUTEX(kernfs_mutex);
 static DEFINE_SPINLOCK(kernfs_rename_lock);	/* kn->parent and ->name */
 static char kernfs_pr_cont_buf[PATH_MAX];	/* protected by rename_lock */
+static DEFINE_SPINLOCK(kernfs_idr_lock);	/* root->ino_idr */
 
 #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
 
@@ -507,6 +508,10 @@ void kernfs_put(struct kernfs_node *kn)
 	struct kernfs_node *parent;
 	struct kernfs_root *root;
 
+	/*
+	 * kernfs_node is freed with ->count 0, kernfs_find_and_get_node_by_ino
+	 * depends on this to filter reused stale node
+	 */
 	if (!kn || !atomic_dec_and_test(&kn->count))
 		return;
 	root = kernfs_root(kn);
@@ -533,7 +538,9 @@ void kernfs_put(struct kernfs_node *kn)
 		simple_xattrs_free(&kn->iattr->xattrs);
 	}
 	kfree(kn->iattr);
-	ida_simple_remove(&root->ino_ida, kn->ino);
+	spin_lock(&kernfs_idr_lock);
+	idr_remove(&root->ino_idr, kn->id.ino);
+	spin_unlock(&kernfs_idr_lock);
 	kmem_cache_free(kernfs_node_cache, kn);
 
 	kn = parent;
@@ -542,7 +549,7 @@ void kernfs_put(struct kernfs_node *kn)
 			goto repeat;
 	} else {
 		/* just released the root kn, free @root too */
-		ida_destroy(&root->ino_ida);
+		idr_destroy(&root->ino_idr);
 		kfree(root);
 	}
 }
@@ -559,7 +566,7 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
 	if (d_really_is_negative(dentry))
 		goto out_bad_unlocked;
 
-	kn = dentry->d_fsdata;
+	kn = kernfs_dentry_node(dentry);
 	mutex_lock(&kernfs_mutex);
 
 	/* The kernfs node has been deactivated */
@@ -567,7 +574,7 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
 		goto out_bad;
 
 	/* The kernfs node has been moved? */
-	if (dentry->d_parent->d_fsdata != kn->parent)
+	if (kernfs_dentry_node(dentry->d_parent) != kn->parent)
 		goto out_bad;
 
 	/* The kernfs node has been renamed */
@@ -587,14 +594,8 @@ out_bad_unlocked:
 	return 0;
 }
 
-static void kernfs_dop_release(struct dentry *dentry)
-{
-	kernfs_put(dentry->d_fsdata);
-}
-
 const struct dentry_operations kernfs_dops = {
 	.d_revalidate	= kernfs_dop_revalidate,
-	.d_release	= kernfs_dop_release,
 };
 
 /**
@@ -610,8 +611,9 @@ const struct dentry_operations kernfs_dops = {
  */
 struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
 {
-	if (dentry->d_sb->s_op == &kernfs_sops)
-		return dentry->d_fsdata;
+	if (dentry->d_sb->s_op == &kernfs_sops &&
+	    !d_really_is_negative(dentry))
+		return kernfs_dentry_node(dentry);
 	return NULL;
 }
 
@@ -620,6 +622,8 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
 					     unsigned flags)
 {
 	struct kernfs_node *kn;
+	u32 gen;
+	int cursor;
 	int ret;
 
 	name = kstrdup_const(name, GFP_KERNEL);
@@ -630,11 +634,25 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
 	if (!kn)
 		goto err_out1;
 
-	ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
+	idr_preload(GFP_KERNEL);
+	spin_lock(&kernfs_idr_lock);
+	cursor = idr_get_cursor(&root->ino_idr);
+	ret = idr_alloc_cyclic(&root->ino_idr, kn, 1, 0, GFP_ATOMIC);
+	if (ret >= 0 && ret < cursor)
+		root->next_generation++;
+	gen = root->next_generation;
+	spin_unlock(&kernfs_idr_lock);
+	idr_preload_end();
 	if (ret < 0)
 		goto err_out2;
-	kn->ino = ret;
+	kn->id.ino = ret;
+	kn->id.generation = gen;
 
+	/*
+	 * set ino first. This barrier is paired with atomic_inc_not_zero in
+	 * kernfs_find_and_get_node_by_ino
+	 */
+	smp_mb__before_atomic();
 	atomic_set(&kn->count, 1);
 	atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
 	RB_CLEAR_NODE(&kn->rb);
@@ -666,6 +684,54 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
 	return kn;
 }
 
+/*
+ * kernfs_find_and_get_node_by_ino - get kernfs_node from inode number
+ * @root: the kernfs root
+ * @ino: inode number
+ *
+ * RETURNS:
+ * NULL on failure. Return a kernfs node with reference counter incremented
+ */
+struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root,
+						    unsigned int ino)
+{
+	struct kernfs_node *kn;
+
+	rcu_read_lock();
+	kn = idr_find(&root->ino_idr, ino);
+	if (!kn)
+		goto out;
+
+	/*
+	 * Since kernfs_node is freed in RCU, it's possible an old node for ino
+	 * is freed, but reused before RCU grace period. But a freed node (see
+	 * kernfs_put) or an incompletedly initialized node (see
+	 * __kernfs_new_node) should have 'count' 0. We can use this fact to
+	 * filter out such node.
+	 */
+	if (!atomic_inc_not_zero(&kn->count)) {
+		kn = NULL;
+		goto out;
+	}
+
+	/*
+	 * The node could be a new node or a reused node. If it's a new node,
+	 * we are ok. If it's reused because of RCU (because of
+	 * SLAB_TYPESAFE_BY_RCU), the __kernfs_new_node always sets its 'ino'
+	 * before 'count'. So if 'count' is uptodate, 'ino' should be uptodate,
+	 * hence we can use 'ino' to filter stale node.
+	 */
+	if (kn->id.ino != ino)
+		goto out;
+	rcu_read_unlock();
+
+	return kn;
+out:
+	rcu_read_unlock();
+	kernfs_put(kn);
+	return NULL;
+}
+
 /**
  *	kernfs_add_one - add kernfs_node to parent without warning
  *	@kn: kernfs_node to be added
@@ -875,13 +941,14 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
 	if (!root)
 		return ERR_PTR(-ENOMEM);
 
-	ida_init(&root->ino_ida);
+	idr_init(&root->ino_idr);
 	INIT_LIST_HEAD(&root->supers);
+	root->next_generation = 1;
 
 	kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
 			       KERNFS_DIR);
 	if (!kn) {
-		ida_destroy(&root->ino_ida);
+		idr_destroy(&root->ino_idr);
 		kfree(root);
 		return ERR_PTR(-ENOMEM);
 	}
@@ -984,7 +1051,7 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir,
 					unsigned int flags)
 {
 	struct dentry *ret;
-	struct kernfs_node *parent = dentry->d_parent->d_fsdata;
+	struct kernfs_node *parent = dir->i_private;
 	struct kernfs_node *kn;
 	struct inode *inode;
 	const void *ns = NULL;
@@ -1001,8 +1068,6 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir,
 		ret = NULL;
 		goto out_unlock;
 	}
-	kernfs_get(kn);
-	dentry->d_fsdata = kn;
 
 	/* attach dentry and inode */
 	inode = kernfs_get_inode(dir->i_sb, kn);
@@ -1039,7 +1104,7 @@ static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
 
 static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
 {
-	struct kernfs_node *kn  = dentry->d_fsdata;
+	struct kernfs_node *kn  = kernfs_dentry_node(dentry);
 	struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
 	int ret;
 
@@ -1059,7 +1124,7 @@ static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
 			     struct inode *new_dir, struct dentry *new_dentry,
 			     unsigned int flags)
 {
-	struct kernfs_node *kn  = old_dentry->d_fsdata;
+	struct kernfs_node *kn = kernfs_dentry_node(old_dentry);
 	struct kernfs_node *new_parent = new_dir->i_private;
 	struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
 	int ret;
@@ -1572,7 +1637,7 @@ static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
 static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
 {
 	struct dentry *dentry = file->f_path.dentry;
-	struct kernfs_node *parent = dentry->d_fsdata;
+	struct kernfs_node *parent = kernfs_dentry_node(dentry);
 	struct kernfs_node *pos = file->private_data;
 	const void *ns = NULL;
 
@@ -1589,7 +1654,7 @@ static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
 		const char *name = pos->name;
 		unsigned int type = dt_type(pos);
 		int len = strlen(name);
-		ino_t ino = pos->ino;
+		ino_t ino = pos->id.ino;
 
 		ctx->pos = pos->hash;
 		file->private_data = pos;
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index e6c8954..9698e51 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -616,7 +616,7 @@ static void kernfs_put_open_node(struct kernfs_node *kn,
 
 static int kernfs_fop_open(struct inode *inode, struct file *file)
 {
-	struct kernfs_node *kn = file->f_path.dentry->d_fsdata;
+	struct kernfs_node *kn = inode->i_private;
 	struct kernfs_root *root = kernfs_root(kn);
 	const struct kernfs_ops *ops;
 	struct kernfs_open_file *of;
@@ -768,7 +768,7 @@ static void kernfs_release_file(struct kernfs_node *kn,
 
 static int kernfs_fop_release(struct inode *inode, struct file *filp)
 {
-	struct kernfs_node *kn = filp->f_path.dentry->d_fsdata;
+	struct kernfs_node *kn = inode->i_private;
 	struct kernfs_open_file *of = kernfs_of(filp);
 
 	if (kn->flags & KERNFS_HAS_RELEASE) {
@@ -835,7 +835,7 @@ void kernfs_drain_open_files(struct kernfs_node *kn)
 static unsigned int kernfs_fop_poll(struct file *filp, poll_table *wait)
 {
 	struct kernfs_open_file *of = kernfs_of(filp);
-	struct kernfs_node *kn = filp->f_path.dentry->d_fsdata;
+	struct kernfs_node *kn = kernfs_dentry_node(filp->f_path.dentry);
 	struct kernfs_open_node *on = kn->attr.open;
 
 	if (!kernfs_get_active(kn))
@@ -895,7 +895,7 @@ repeat:
 		 * have the matching @file available.  Look up the inodes
 		 * and generate the events manually.
 		 */
-		inode = ilookup(info->sb, kn->ino);
+		inode = ilookup(info->sb, kn->id.ino);
 		if (!inode)
 			continue;
 
@@ -903,7 +903,7 @@ repeat:
 		if (parent) {
 			struct inode *p_inode;
 
-			p_inode = ilookup(info->sb, parent->ino);
+			p_inode = ilookup(info->sb, parent->id.ino);
 			if (p_inode) {
 				fsnotify(p_inode, FS_MODIFY | FS_EVENT_ON_CHILD,
 					 inode, FSNOTIFY_EVENT_INODE, kn->name, 0);
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index fb4b4a7..a343039 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -112,7 +112,7 @@ int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr)
 int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)
 {
 	struct inode *inode = d_inode(dentry);
-	struct kernfs_node *kn = dentry->d_fsdata;
+	struct kernfs_node *kn = inode->i_private;
 	int error;
 
 	if (!kn)
@@ -154,7 +154,7 @@ static int kernfs_node_setsecdata(struct kernfs_iattrs *attrs, void **secdata,
 
 ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
 {
-	struct kernfs_node *kn = dentry->d_fsdata;
+	struct kernfs_node *kn = kernfs_dentry_node(dentry);
 	struct kernfs_iattrs *attrs;
 
 	attrs = kernfs_iattrs(kn);
@@ -203,8 +203,8 @@ static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
 int kernfs_iop_getattr(const struct path *path, struct kstat *stat,
 		       u32 request_mask, unsigned int query_flags)
 {
-	struct kernfs_node *kn = path->dentry->d_fsdata;
 	struct inode *inode = d_inode(path->dentry);
+	struct kernfs_node *kn = inode->i_private;
 
 	mutex_lock(&kernfs_mutex);
 	kernfs_refresh_inode(kn, inode);
@@ -220,6 +220,7 @@ static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode)
 	inode->i_private = kn;
 	inode->i_mapping->a_ops = &kernfs_aops;
 	inode->i_op = &kernfs_iops;
+	inode->i_generation = kn->id.generation;
 
 	set_default_inode_attr(inode, kn->mode);
 	kernfs_refresh_inode(kn, inode);
@@ -265,7 +266,7 @@ struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
 {
 	struct inode *inode;
 
-	inode = iget_locked(sb, kn->ino);
+	inode = iget_locked(sb, kn->id.ino);
 	if (inode && (inode->i_state & I_NEW))
 		kernfs_init_inode(kn, inode);
 
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index 2d5144a..0f260dc 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -70,6 +70,13 @@ struct kernfs_super_info {
 };
 #define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info))
 
+static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry)
+{
+	if (d_really_is_negative(dentry))
+		return NULL;
+	return d_inode(dentry)->i_private;
+}
+
 extern const struct super_operations kernfs_sops;
 extern struct kmem_cache *kernfs_node_cache;
 
@@ -98,6 +105,8 @@ int kernfs_add_one(struct kernfs_node *kn);
 struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
 				    const char *name, umode_t mode,
 				    unsigned flags);
+struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root,
+						    unsigned int ino);
 
 /*
  * file.c
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index d5b149a..95a7c88 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -16,6 +16,7 @@
 #include <linux/pagemap.h>
 #include <linux/namei.h>
 #include <linux/seq_file.h>
+#include <linux/exportfs.h>
 
 #include "kernfs-internal.h"
 
@@ -33,7 +34,7 @@ static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data)
 
 static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry)
 {
-	struct kernfs_root *root = kernfs_root(dentry->d_fsdata);
+	struct kernfs_root *root = kernfs_root(kernfs_dentry_node(dentry));
 	struct kernfs_syscall_ops *scops = root->syscall_ops;
 
 	if (scops && scops->show_options)
@@ -43,7 +44,7 @@ static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry)
 
 static int kernfs_sop_show_path(struct seq_file *sf, struct dentry *dentry)
 {
-	struct kernfs_node *node = dentry->d_fsdata;
+	struct kernfs_node *node = kernfs_dentry_node(dentry);
 	struct kernfs_root *root = kernfs_root(node);
 	struct kernfs_syscall_ops *scops = root->syscall_ops;
 
@@ -64,6 +65,78 @@ const struct super_operations kernfs_sops = {
 	.show_path	= kernfs_sop_show_path,
 };
 
+/*
+ * Similar to kernfs_fh_get_inode, this one gets kernfs node from inode
+ * number and generation
+ */
+struct kernfs_node *kernfs_get_node_by_id(struct kernfs_root *root,
+	const union kernfs_node_id *id)
+{
+	struct kernfs_node *kn;
+
+	kn = kernfs_find_and_get_node_by_ino(root, id->ino);
+	if (!kn)
+		return NULL;
+	if (kn->id.generation != id->generation) {
+		kernfs_put(kn);
+		return NULL;
+	}
+	return kn;
+}
+
+static struct inode *kernfs_fh_get_inode(struct super_block *sb,
+		u64 ino, u32 generation)
+{
+	struct kernfs_super_info *info = kernfs_info(sb);
+	struct inode *inode;
+	struct kernfs_node *kn;
+
+	if (ino == 0)
+		return ERR_PTR(-ESTALE);
+
+	kn = kernfs_find_and_get_node_by_ino(info->root, ino);
+	if (!kn)
+		return ERR_PTR(-ESTALE);
+	inode = kernfs_get_inode(sb, kn);
+	kernfs_put(kn);
+	if (!inode)
+		return ERR_PTR(-ESTALE);
+
+	if (generation && inode->i_generation != generation) {
+		/* we didn't find the right inode.. */
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+	return inode;
+}
+
+static struct dentry *kernfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+				    kernfs_fh_get_inode);
+}
+
+static struct dentry *kernfs_fh_to_parent(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+				    kernfs_fh_get_inode);
+}
+
+static struct dentry *kernfs_get_parent_dentry(struct dentry *child)
+{
+	struct kernfs_node *kn = kernfs_dentry_node(child);
+
+	return d_obtain_alias(kernfs_get_inode(child->d_sb, kn->parent));
+}
+
+static const struct export_operations kernfs_export_ops = {
+	.fh_to_dentry	= kernfs_fh_to_dentry,
+	.fh_to_parent	= kernfs_fh_to_parent,
+	.get_parent	= kernfs_get_parent_dentry,
+};
+
 /**
  * kernfs_root_from_sb - determine kernfs_root associated with a super_block
  * @sb: the super_block in question
@@ -159,6 +232,8 @@ static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
 	sb->s_magic = magic;
 	sb->s_op = &kernfs_sops;
 	sb->s_xattr = kernfs_xattr_handlers;
+	if (info->root->flags & KERNFS_ROOT_SUPPORT_EXPORTOP)
+		sb->s_export_op = &kernfs_export_ops;
 	sb->s_time_gran = 1;
 
 	/* get root inode, initialize and unlock it */
@@ -176,8 +251,6 @@ static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
 		pr_debug("%s: could not get root dentry!\n", __func__);
 		return -ENOMEM;
 	}
-	kernfs_get(info->root->kn);
-	root->d_fsdata = info->root->kn;
 	sb->s_root = root;
 	sb->s_d_op = &kernfs_dops;
 	return 0;
@@ -283,7 +356,6 @@ struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
 void kernfs_kill_sb(struct super_block *sb)
 {
 	struct kernfs_super_info *info = kernfs_info(sb);
-	struct kernfs_node *root_kn = sb->s_root->d_fsdata;
 
 	mutex_lock(&kernfs_mutex);
 	list_del(&info->node);
@@ -295,7 +367,6 @@ void kernfs_kill_sb(struct super_block *sb)
 	 */
 	kill_anon_super(sb);
 	kfree(info);
-	kernfs_put(root_kn);
 }
 
 /**
@@ -330,7 +401,16 @@ struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns)
 
 void __init kernfs_init(void)
 {
+
+	/*
+	 * the slab is freed in RCU context, so kernfs_find_and_get_node_by_ino
+	 * can access the slab lock free. This could introduce stale nodes,
+	 * please see how kernfs_find_and_get_node_by_ino filters out stale
+	 * nodes.
+	 */
 	kernfs_node_cache = kmem_cache_create("kernfs_node_cache",
 					      sizeof(struct kernfs_node),
-					      0, SLAB_PANIC, NULL);
+					      0,
+					      SLAB_PANIC | SLAB_TYPESAFE_BY_RCU,
+					      NULL);
 }
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index 1684af4..08ccabd 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -98,9 +98,9 @@ static int kernfs_get_target_path(struct kernfs_node *parent,
 	return 0;
 }
 
-static int kernfs_getlink(struct dentry *dentry, char *path)
+static int kernfs_getlink(struct inode *inode, char *path)
 {
-	struct kernfs_node *kn = dentry->d_fsdata;
+	struct kernfs_node *kn = inode->i_private;
 	struct kernfs_node *parent = kn->parent;
 	struct kernfs_node *target = kn->symlink.target_kn;
 	int error;
@@ -124,7 +124,7 @@ static const char *kernfs_iop_get_link(struct dentry *dentry,
 	body = kzalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!body)
 		return ERR_PTR(-ENOMEM);
-	error = kernfs_getlink(dentry, body);
+	error = kernfs_getlink(inode, body);
 	if (unlikely(error < 0)) {
 		kfree(body);
 		return ERR_PTR(error);
diff --git a/fs/mpage.c b/fs/mpage.c
index 2e4c41c..37bb77c 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -83,7 +83,7 @@ mpage_alloc(struct block_device *bdev,
 	}
 
 	if (bio) {
-		bio->bi_bdev = bdev;
+		bio_set_dev(bio, bdev);
 		bio->bi_iter.bi_sector = first_sector;
 	}
 	return bio;
diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index d8863a8..995d707 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -130,7 +130,7 @@ bl_alloc_init_bio(int npg, struct block_device *bdev, sector_t disk_sector,
 
 	if (bio) {
 		bio->bi_iter.bi_sector = disk_sector;
-		bio->bi_bdev = bdev;
+		bio_set_dev(bio, bdev);
 		bio->bi_end_io = end_io;
 		bio->bi_private = par;
 	}
diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index e73c86d..6c5009c 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -400,7 +400,7 @@ static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
 			bio = bio_alloc(GFP_NOIO, nr_vecs);
 	}
 	if (likely(bio)) {
-		bio->bi_bdev = nilfs->ns_bdev;
+		bio_set_dev(bio, nilfs->ns_bdev);
 		bio->bi_iter.bi_sector =
 			start << (nilfs->ns_blocksize_bits - 9);
 	}
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 56ac07c..d020604 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -553,7 +553,7 @@ static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 
 	/* Must put everything in 512 byte sectors for the bio... */
 	bio->bi_iter.bi_sector = (reg->hr_start_block + cs) << (bits - 9);
-	bio->bi_bdev = reg->hr_bdev;
+	bio_set_dev(bio, reg->hr_bdev);
 	bio->bi_private = wc;
 	bio->bi_end_io = o2hb_bio_end_io;
 	bio_set_op_attrs(bio, op, op_flags);
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index f9efd67..fffae13 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -540,7 +540,7 @@ xfs_init_bio_from_bh(
 	struct buffer_head	*bh)
 {
 	bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
-	bio->bi_bdev = bh->b_bdev;
+	bio_set_dev(bio, bh->b_bdev);
 }
 
 static struct xfs_ioend *
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 72f0384..b1c9711 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1281,7 +1281,7 @@ next_chunk:
 	nr_pages = min(total_nr_pages, BIO_MAX_PAGES);
 
 	bio = bio_alloc(GFP_NOIO, nr_pages);
-	bio->bi_bdev = bp->b_target->bt_bdev;
+	bio_set_dev(bio, bp->b_target->bt_bdev);
 	bio->bi_iter.bi_sector = sector;
 	bio->bi_end_io = xfs_buf_bio_end_io;
 	bio->bi_private = bp;