1 files changed, 397 insertions, 292 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index af97ddcc6b3e..765deefda92b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -29,7 +29,6 @@
 #include "tree-log.h"
 #include "free-space-cache.h"
 #include "free-space-tree.h"
-#include "inode-map.h"
 #include "check-integrity.h"
 #include "rcu-string.h"
 #include "dev-replace.h"
@@ -42,6 +41,7 @@
 #include "block-group.h"
 #include "discard.h"
 #include "space-info.h"
+#include "zoned.h"
 
 #define BTRFS_SUPER_FLAG_SUPP	(BTRFS_HEADER_FLAG_WRITTEN |\
 				 BTRFS_HEADER_FLAG_RELOC |\
@@ -109,15 +109,13 @@ static void btrfs_free_csum_hash(struct btrfs_fs_info *fs_info)
  * just before they are sent down the IO stack.
  */
 struct async_submit_bio {
-	void *private_data;
+	struct inode *inode;
 	struct bio *bio;
 	extent_submit_bio_start_t *submit_bio_start;
 	int mirror_num;
-	/*
-	 * bio_offset is optional, can be used if the pages in the bio
-	 * can't tell us where in the file the bio should go
-	 */
-	u64 bio_offset;
+
+	/* Optional parameter for submit_bio_start used by direct io */
+	u64 dio_file_offset;
 	struct btrfs_work work;
 	blk_status_t status;
 };
@@ -150,40 +148,41 @@ struct async_submit_bio {
 #  error
 # endif
 
+#define DEFINE_LEVEL(stem, level)					\
+	.names[level] = "btrfs-" stem "-0" #level,
+
+#define DEFINE_NAME(stem)						\
+	DEFINE_LEVEL(stem, 0)						\
+	DEFINE_LEVEL(stem, 1)						\
+	DEFINE_LEVEL(stem, 2)						\
+	DEFINE_LEVEL(stem, 3)						\
+	DEFINE_LEVEL(stem, 4)						\
+	DEFINE_LEVEL(stem, 5)						\
+	DEFINE_LEVEL(stem, 6)						\
+	DEFINE_LEVEL(stem, 7)
+
 static struct btrfs_lockdep_keyset {
 	u64			id;		/* root objectid */
-	const char		*name_stem;	/* lock name stem */
-	char			names[BTRFS_MAX_LEVEL + 1][20];
-	struct lock_class_key	keys[BTRFS_MAX_LEVEL + 1];
+	/* Longest entry: btrfs-free-space-00 */
+	char			names[BTRFS_MAX_LEVEL][20];
+	struct lock_class_key	keys[BTRFS_MAX_LEVEL];
 } btrfs_lockdep_keysets[] = {
-	{ .id = BTRFS_ROOT_TREE_OBJECTID,	.name_stem = "root"	},
-	{ .id = BTRFS_EXTENT_TREE_OBJECTID,	.name_stem = "extent"	},
-	{ .id = BTRFS_CHUNK_TREE_OBJECTID,	.name_stem = "chunk"	},
-	{ .id = BTRFS_DEV_TREE_OBJECTID,	.name_stem = "dev"	},
-	{ .id = BTRFS_FS_TREE_OBJECTID,		.name_stem = "fs"	},
-	{ .id = BTRFS_CSUM_TREE_OBJECTID,	.name_stem = "csum"	},
-	{ .id = BTRFS_QUOTA_TREE_OBJECTID,	.name_stem = "quota"	},
-	{ .id = BTRFS_TREE_LOG_OBJECTID,	.name_stem = "log"	},
-	{ .id = BTRFS_TREE_RELOC_OBJECTID,	.name_stem = "treloc"	},
-	{ .id = BTRFS_DATA_RELOC_TREE_OBJECTID,	.name_stem = "dreloc"	},
-	{ .id = BTRFS_UUID_TREE_OBJECTID,	.name_stem = "uuid"	},
-	{ .id = BTRFS_FREE_SPACE_TREE_OBJECTID,	.name_stem = "free-space" },
-	{ .id = 0,				.name_stem = "tree"	},
+	{ .id = BTRFS_ROOT_TREE_OBJECTID,	DEFINE_NAME("root")	},
+	{ .id = BTRFS_EXTENT_TREE_OBJECTID,	DEFINE_NAME("extent")	},
+	{ .id = BTRFS_CHUNK_TREE_OBJECTID,	DEFINE_NAME("chunk")	},
+	{ .id = BTRFS_DEV_TREE_OBJECTID,	DEFINE_NAME("dev")	},
+	{ .id = BTRFS_CSUM_TREE_OBJECTID,	DEFINE_NAME("csum")	},
+	{ .id = BTRFS_QUOTA_TREE_OBJECTID,	DEFINE_NAME("quota")	},
+	{ .id = BTRFS_TREE_LOG_OBJECTID,	DEFINE_NAME("log")	},
+	{ .id = BTRFS_TREE_RELOC_OBJECTID,	DEFINE_NAME("treloc")	},
+	{ .id = BTRFS_DATA_RELOC_TREE_OBJECTID,	DEFINE_NAME("dreloc")	},
+	{ .id = BTRFS_UUID_TREE_OBJECTID,	DEFINE_NAME("uuid")	},
+	{ .id = BTRFS_FREE_SPACE_TREE_OBJECTID,	DEFINE_NAME("free-space") },
+	{ .id = 0,				DEFINE_NAME("tree")	},
 };
 
-void __init btrfs_init_lockdep(void)
-{
-	int i, j;
-
-	/* initialize lockdep class names */
-	for (i = 0; i < ARRAY_SIZE(btrfs_lockdep_keysets); i++) {
-		struct btrfs_lockdep_keyset *ks = &btrfs_lockdep_keysets[i];
-
-		for (j = 0; j < ARRAY_SIZE(ks->names); j++)
-			snprintf(ks->names[j], sizeof(ks->names[j]),
-				 "btrfs-%s-%02d", ks->name_stem, j);
-	}
-}
+#undef DEFINE_LEVEL
+#undef DEFINE_NAME
 
 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
 				    int level)
@@ -210,15 +209,16 @@ static void csum_tree_block(struct extent_buffer *buf, u8 *result)
 {
 	struct btrfs_fs_info *fs_info = buf->fs_info;
 	const int num_pages = fs_info->nodesize >> PAGE_SHIFT;
+	const int first_page_part = min_t(u32, PAGE_SIZE, fs_info->nodesize);
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 	char *kaddr;
 	int i;
 
 	shash->tfm = fs_info->csum_shash;
 	crypto_shash_init(shash);
-	kaddr = page_address(buf->pages[0]);
+	kaddr = page_address(buf->pages[0]) + offset_in_page(buf->start);
 	crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,
-			    PAGE_SIZE - BTRFS_CSUM_SIZE);
+			    first_page_part - BTRFS_CSUM_SIZE);
 
 	for (i = 1; i < num_pages; i++) {
 		kaddr = page_address(buf->pages[i]);
@@ -248,10 +248,8 @@ static int verify_parent_transid(struct extent_io_tree *io_tree,
 	if (atomic)
 		return -EAGAIN;
 
-	if (need_lock) {
+	if (need_lock)
 		btrfs_tree_read_lock(eb);
-		btrfs_set_lock_blocking_read(eb);
-	}
 
 	lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
 			 &cached_state);
@@ -280,7 +278,7 @@ out:
 	unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
 			     &cached_state);
 	if (need_lock)
-		btrfs_tree_read_unlock_blocking(eb);
+		btrfs_tree_read_unlock(eb);
 	return ret;
 }
 
@@ -319,7 +317,7 @@ static int btrfs_check_super_csum(struct btrfs_fs_info *fs_info,
 	crypto_shash_digest(shash, raw_disk_sb + BTRFS_CSUM_SIZE,
 			    BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE, result);
 
-	if (memcmp(disk_sb->csum, result, btrfs_super_csum_size(disk_sb)))
+	if (memcmp(disk_sb->csum, result, fs_info->csum_size))
 		return 1;
 
 	return 0;
@@ -443,16 +441,16 @@ static int btree_read_extent_buffer_pages(struct extent_buffer *eb,
 }
 
 /*
- * checksum a dirty tree block before IO.  This has extra checks to make sure
- * we only fill in the checksum field in the first page of a multi-page block
+ * Checksum a dirty tree block before IO.  This has extra checks to make sure
+ * we only fill in the checksum field in the first page of a multi-page block.
+ * For subpage extent buffers we need bvec to also read the offset in the page.
  */
-
-static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page)
+static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct bio_vec *bvec)
 {
+	struct page *page = bvec->bv_page;
 	u64 start = page_offset(page);
 	u64 found_start;
 	u8 result[BTRFS_CSUM_SIZE];
-	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 	struct extent_buffer *eb;
 	int ret;
 
@@ -489,7 +487,7 @@ static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page)
 		WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
 		return ret;
 	}
-	write_extent_buffer(eb, result, 0, csum_size);
+	write_extent_buffer(eb, result, 0, fs_info->csum_size);
 
 	return 0;
 }
@@ -523,65 +521,37 @@ static int check_tree_block_fsid(struct extent_buffer *eb)
 	return 1;
 }
 
-int btrfs_validate_metadata_buffer(struct btrfs_io_bio *io_bio, u64 phy_offset,
-				   struct page *page, u64 start, u64 end,
-				   int mirror)
+/* Do basic extent buffer checks at read time */
+static int validate_extent_buffer(struct extent_buffer *eb)
 {
+	struct btrfs_fs_info *fs_info = eb->fs_info;
 	u64 found_start;
-	int found_level;
-	struct extent_buffer *eb;
-	struct btrfs_fs_info *fs_info;
-	u16 csum_size;
-	int ret = 0;
+	const u32 csum_size = fs_info->csum_size;
+	u8 found_level;
 	u8 result[BTRFS_CSUM_SIZE];
-	int reads_done;
-
-	if (!page->private)
-		goto out;
-
-	eb = (struct extent_buffer *)page->private;
-	fs_info = eb->fs_info;
-	csum_size = btrfs_super_csum_size(fs_info->super_copy);
-
-	/* the pending IO might have been the only thing that kept this buffer
-	 * in memory.  Make sure we have a ref for all this other checks
-	 */
-	atomic_inc(&eb->refs);
-
-	reads_done = atomic_dec_and_test(&eb->io_pages);
-	if (!reads_done)
-		goto err;
-
-	eb->read_mirror = mirror;
-	if (test_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags)) {
-		ret = -EIO;
-		goto err;
-	}
+	int ret = 0;
 
 	found_start = btrfs_header_bytenr(eb);
 	if (found_start != eb->start) {
 		btrfs_err_rl(fs_info, "bad tree block start, want %llu have %llu",
 			     eb->start, found_start);
 		ret = -EIO;
-		goto err;
+		goto out;
 	}
 	if (check_tree_block_fsid(eb)) {
 		btrfs_err_rl(fs_info, "bad fsid on block %llu",
 			     eb->start);
 		ret = -EIO;
-		goto err;
+		goto out;
 	}
 	found_level = btrfs_header_level(eb);
 	if (found_level >= BTRFS_MAX_LEVEL) {
 		btrfs_err(fs_info, "bad tree block level %d on %llu",
 			  (int)btrfs_header_level(eb), eb->start);
 		ret = -EIO;
-		goto err;
+		goto out;
 	}
 
-	btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
-				       eb, found_level);
-
 	csum_tree_block(eb, result);
 
 	if (memcmp_extent_buffer(eb, result, 0, csum_size)) {
@@ -595,7 +565,7 @@ int btrfs_validate_metadata_buffer(struct btrfs_io_bio *io_bio, u64 phy_offset,
 			      CSUM_FMT_VALUE(csum_size, result),
 			      btrfs_header_level(eb));
 		ret = -EUCLEAN;
-		goto err;
+		goto out;
 	}
 
 	/*
@@ -617,6 +587,37 @@ int btrfs_validate_metadata_buffer(struct btrfs_io_bio *io_bio, u64 phy_offset,
 		btrfs_err(fs_info,
 			  "block=%llu read time tree block corruption detected",
 			  eb->start);
+out:
+	return ret;
+}
+
+int btrfs_validate_metadata_buffer(struct btrfs_io_bio *io_bio,
+				   struct page *page, u64 start, u64 end,
+				   int mirror)
+{
+	struct extent_buffer *eb;
+	int ret = 0;
+	int reads_done;
+
+	ASSERT(page->private);
+	eb = (struct extent_buffer *)page->private;
+
+	/*
+	 * The pending IO might have been the only thing that kept this buffer
+	 * in memory.  Make sure we have a ref for all this other checks
+	 */
+	atomic_inc(&eb->refs);
+
+	reads_done = atomic_dec_and_test(&eb->io_pages);
+	if (!reads_done)
+		goto err;
+
+	eb->read_mirror = mirror;
+	if (test_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags)) {
+		ret = -EIO;
+		goto err;
+	}
+	ret = validate_extent_buffer(eb);
 err:
 	if (reads_done &&
 	    test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
@@ -632,7 +633,7 @@ err:
 		clear_extent_buffer_uptodate(eb);
 	}
 	free_extent_buffer(eb);
-out:
+
 	return ret;
 }
 
@@ -694,8 +695,8 @@ static void run_one_async_start(struct btrfs_work *work)
 	blk_status_t ret;
 
 	async = container_of(work, struct  async_submit_bio, work);
-	ret = async->submit_bio_start(async->private_data, async->bio,
-				      async->bio_offset);
+	ret = async->submit_bio_start(async->inode, async->bio,
+				      async->dio_file_offset);
 	if (ret)
 		async->status = ret;
 }
@@ -715,7 +716,7 @@ static void run_one_async_done(struct btrfs_work *work)
 	blk_status_t ret;
 
 	async = container_of(work, struct  async_submit_bio, work);
-	inode = async->private_data;
+	inode = async->inode;
 
 	/* If an error occurred we just want to clean up the bio and move on */
 	if (async->status) {
@@ -745,18 +746,19 @@ static void run_one_async_free(struct btrfs_work *work)
 	kfree(async);
 }
 
-blk_status_t btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
+blk_status_t btrfs_wq_submit_bio(struct inode *inode, struct bio *bio,
 				 int mirror_num, unsigned long bio_flags,
-				 u64 bio_offset, void *private_data,
+				 u64 dio_file_offset,
 				 extent_submit_bio_start_t *submit_bio_start)
 {
+	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
 	struct async_submit_bio *async;
 
 	async = kmalloc(sizeof(*async), GFP_NOFS);
 	if (!async)
 		return BLK_STS_RESOURCE;
 
-	async->private_data = private_data;
+	async->inode = inode;
 	async->bio = bio;
 	async->mirror_num = mirror_num;
 	async->submit_bio_start = submit_bio_start;
@@ -764,7 +766,7 @@ blk_status_t btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
 	btrfs_init_work(&async->work, run_one_async_start, run_one_async_done,
 			run_one_async_free);
 
-	async->bio_offset = bio_offset;
+	async->dio_file_offset = dio_file_offset;
 
 	async->status = 0;
 
@@ -785,7 +787,7 @@ static blk_status_t btree_csum_one_bio(struct bio *bio)
 	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_segment_all(bvec, bio, iter_all) {
 		root = BTRFS_I(bvec->bv_page->mapping->host)->root;
-		ret = csum_dirty_buffer(root->fs_info, bvec->bv_page);
+		ret = csum_dirty_buffer(root->fs_info, bvec);
 		if (ret)
 			break;
 	}
@@ -793,8 +795,8 @@ static blk_status_t btree_csum_one_bio(struct bio *bio)
 	return errno_to_blk_status(ret);
 }
 
-static blk_status_t btree_submit_bio_start(void *private_data, struct bio *bio,
-					     u64 bio_offset)
+static blk_status_t btree_submit_bio_start(struct inode *inode, struct bio *bio,
+					   u64 dio_file_offset)
 {
 	/*
 	 * when we're called for a write, we're already in the async
@@ -840,8 +842,8 @@ blk_status_t btrfs_submit_metadata_bio(struct inode *inode, struct bio *bio,
 		 * kthread helpers are used to submit writes so that
 		 * checksumming can happen in parallel across all CPUs
 		 */
-		ret = btrfs_wq_submit_bio(fs_info, bio, mirror_num, 0,
-					  0, inode, btree_submit_bio_start);
+		ret = btrfs_wq_submit_bio(inode, bio, mirror_num, 0,
+					  0, btree_submit_bio_start);
 	}
 
 	if (ret)
@@ -947,47 +949,33 @@ static const struct address_space_operations btree_aops = {
 	.set_page_dirty = btree_set_page_dirty,
 };
 
-void readahead_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr)
-{
-	struct extent_buffer *buf = NULL;
-	int ret;
-
-	buf = btrfs_find_create_tree_block(fs_info, bytenr);
-	if (IS_ERR(buf))
-		return;
-
-	ret = read_extent_buffer_pages(buf, WAIT_NONE, 0);
-	if (ret < 0)
-		free_extent_buffer_stale(buf);
-	else
-		free_extent_buffer(buf);
-}
-
 struct extent_buffer *btrfs_find_create_tree_block(
 						struct btrfs_fs_info *fs_info,
-						u64 bytenr)
+						u64 bytenr, u64 owner_root,
+						int level)
 {
 	if (btrfs_is_testing(fs_info))
 		return alloc_test_extent_buffer(fs_info, bytenr);
-	return alloc_extent_buffer(fs_info, bytenr);
+	return alloc_extent_buffer(fs_info, bytenr, owner_root, level);
 }
 
 /*
  * Read tree block at logical address @bytenr and do variant basic but critical
  * verification.
  *
+ * @owner_root:		the objectid of the root owner for this block.
  * @parent_transid:	expected transid of this tree block, skip check if 0
  * @level:		expected level, mandatory check
  * @first_key:		expected key in slot 0, skip check if NULL
  */
 struct extent_buffer *read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
-				      u64 parent_transid, int level,
-				      struct btrfs_key *first_key)
+				      u64 owner_root, u64 parent_transid,
+				      int level, struct btrfs_key *first_key)
 {
 	struct extent_buffer *buf = NULL;
 	int ret;
 
-	buf = btrfs_find_create_tree_block(fs_info, bytenr);
+	buf = btrfs_find_create_tree_block(fs_info, bytenr, owner_root, level);
 	if (IS_ERR(buf))
 		return buf;
 
@@ -1012,8 +1000,6 @@ void btrfs_clean_tree_block(struct extent_buffer *buf)
 			percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
 						 -buf->len,
 						 fs_info->dirty_metadata_batch);
-			/* ugh, clear_extent_buffer_dirty needs to lock the page */
-			btrfs_set_lock_blocking_write(buf);
 			clear_extent_buffer_dirty(buf);
 		}
 	}
@@ -1155,7 +1141,7 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 	if (IS_ERR(leaf)) {
 		ret = PTR_ERR(leaf);
 		leaf = NULL;
-		goto fail;
+		goto fail_unlock;
 	}
 
 	root->node = leaf;
@@ -1164,8 +1150,8 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 	root->commit_root = btrfs_root_node(root);
 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
 
-	root->root_item.flags = 0;
-	root->root_item.byte_limit = 0;
+	btrfs_set_root_flags(&root->root_item, 0);
+	btrfs_set_root_limit(&root->root_item, 0);
 	btrfs_set_root_bytenr(&root->root_item, leaf->start);
 	btrfs_set_root_generation(&root->root_item, trans->transid);
 	btrfs_set_root_level(&root->root_item, 0);
@@ -1177,7 +1163,9 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 		generate_random_guid(root->root_item.uuid);
 	else
 		export_guid(root->root_item.uuid, &guid_null);
-	root->root_item.drop_level = 0;
+	btrfs_set_root_drop_level(&root->root_item, 0);
+
+	btrfs_tree_unlock(leaf);
 
 	key.objectid = objectid;
 	key.type = BTRFS_ROOT_ITEM_KEY;
@@ -1186,13 +1174,12 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 	if (ret)
 		goto fail;
 
-	btrfs_tree_unlock(leaf);
-
 	return root;
 
-fail:
+fail_unlock:
 	if (leaf)
 		btrfs_tree_unlock(leaf);
+fail:
 	btrfs_put_root(root);
 
 	return ERR_PTR(ret);
@@ -1307,7 +1294,7 @@ static struct btrfs_root *read_tree_root_path(struct btrfs_root *tree_root,
 	level = btrfs_root_level(&root->root_item);
 	root->node = read_tree_block(fs_info,
 				     btrfs_root_bytenr(&root->root_item),
-				     generation, level, NULL);
+				     key->objectid, generation, level, NULL);
 	if (IS_ERR(root->node)) {
 		ret = PTR_ERR(root->node);
 		root->node = NULL;
@@ -1348,14 +1335,6 @@ static int btrfs_init_fs_root(struct btrfs_root *root, dev_t anon_dev)
 	int ret;
 	unsigned int nofs_flag;
 
-	root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
-	root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
-					GFP_NOFS);
-	if (!root->free_ino_pinned || !root->free_ino_ctl) {
-		ret = -ENOMEM;
-		goto fail;
-	}
-
 	/*
 	 * We might be called under a transaction (e.g. indirect backref
 	 * resolution) which could deadlock if it triggers memory reclaim
@@ -1372,10 +1351,6 @@ static int btrfs_init_fs_root(struct btrfs_root *root, dev_t anon_dev)
 		btrfs_check_and_init_root_item(&root->root_item);
 	}
 
-	btrfs_init_free_ino_ctl(root);
-	spin_lock_init(&root->ino_cache_lock);
-	init_waitqueue_head(&root->ino_cache_wait);
-
 	/*
 	 * Don't assign anonymous block device to roots that are not exposed to
 	 * userspace, the id pool is limited to 1M
@@ -1774,13 +1749,13 @@ static int transaction_kthread(void *arg)
 	struct btrfs_trans_handle *trans;
 	struct btrfs_transaction *cur;
 	u64 transid;
-	time64_t now;
+	time64_t delta;
 	unsigned long delay;
 	bool cannot_commit;
 
 	do {
 		cannot_commit = false;
-		delay = HZ * fs_info->commit_interval;
+		delay = msecs_to_jiffies(fs_info->commit_interval * 1000);
 		mutex_lock(&fs_info->transaction_kthread_mutex);
 
 		spin_lock(&fs_info->trans_lock);
@@ -1790,12 +1765,13 @@ static int transaction_kthread(void *arg)
 			goto sleep;
 		}
 
-		now = ktime_get_seconds();
+		delta = ktime_get_seconds() - cur->start_time;
 		if (cur->state < TRANS_STATE_COMMIT_START &&
-		    (now < cur->start_time ||
-		     now - cur->start_time < fs_info->commit_interval)) {
+		    delta < fs_info->commit_interval) {
 			spin_unlock(&fs_info->trans_lock);
-			delay = HZ * 5;
+			delay -= msecs_to_jiffies((delta - 1) * 1000);
+			delay = min(delay,
+				    msecs_to_jiffies(fs_info->commit_interval * 1000));
 			goto sleep;
 		}
 		transid = cur->transid;
@@ -2044,8 +2020,6 @@ void btrfs_put_root(struct btrfs_root *root)
 			free_anon_bdev(root->anon_dev);
 		btrfs_drew_lock_destroy(&root->snapshot_lock);
 		free_root_extent_buffers(root);
-		kfree(root->free_ino_ctl);
-		kfree(root->free_ino_pinned);
 #ifdef CONFIG_BTRFS_DEBUG
 		spin_lock(&root->fs_info->fs_roots_radix_lock);
 		list_del_init(&root->leak_list);
@@ -2260,8 +2234,9 @@ static int btrfs_replay_log(struct btrfs_fs_info *fs_info,
 		return -ENOMEM;
 
 	log_tree_root->node = read_tree_block(fs_info, bytenr,
-					      fs_info->generation + 1,
-					      level, NULL);
+					      BTRFS_TREE_LOG_OBJECTID,
+					      fs_info->generation + 1, level,
+					      NULL);
 	if (IS_ERR(log_tree_root->node)) {
 		btrfs_warn(fs_info, "failed to read log tree");
 		ret = PTR_ERR(log_tree_root->node);
@@ -2306,30 +2281,42 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
 
 	root = btrfs_read_tree_root(tree_root, &location);
 	if (IS_ERR(root)) {
-		ret = PTR_ERR(root);
-		goto out;
+		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+			ret = PTR_ERR(root);
+			goto out;
+		}
+	} else {
+		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+		fs_info->extent_root = root;
 	}
-	set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
-	fs_info->extent_root = root;
 
 	location.objectid = BTRFS_DEV_TREE_OBJECTID;
 	root = btrfs_read_tree_root(tree_root, &location);
 	if (IS_ERR(root)) {
-		ret = PTR_ERR(root);
-		goto out;
+		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+			ret = PTR_ERR(root);
+			goto out;
+		}
+	} else {
+		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+		fs_info->dev_root = root;
+		btrfs_init_devices_late(fs_info);
 	}
-	set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
-	fs_info->dev_root = root;
-	btrfs_init_devices_late(fs_info);
 
-	location.objectid = BTRFS_CSUM_TREE_OBJECTID;
-	root = btrfs_read_tree_root(tree_root, &location);
-	if (IS_ERR(root)) {
-		ret = PTR_ERR(root);
-		goto out;
+	/* If IGNOREDATACSUMS is set don't bother reading the csum root. */
+	if (!btrfs_test_opt(fs_info, IGNOREDATACSUMS)) {
+		location.objectid = BTRFS_CSUM_TREE_OBJECTID;
+		root = btrfs_read_tree_root(tree_root, &location);
+		if (IS_ERR(root)) {
+			if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+				ret = PTR_ERR(root);
+				goto out;
+			}
+		} else {
+			set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+			fs_info->csum_root = root;
+		}
 	}
-	set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
-	fs_info->csum_root = root;
 
 	/*
 	 * This tree can share blocks with some other fs tree during relocation
@@ -2338,11 +2325,14 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
 	root = btrfs_get_fs_root(tree_root->fs_info,
 				 BTRFS_DATA_RELOC_TREE_OBJECTID, true);
 	if (IS_ERR(root)) {
-		ret = PTR_ERR(root);
-		goto out;
+		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+			ret = PTR_ERR(root);
+			goto out;
+		}
+	} else {
+		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+		fs_info->data_reloc_root = root;
 	}
-	set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
-	fs_info->data_reloc_root = root;
 
 	location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
 	root = btrfs_read_tree_root(tree_root, &location);
@@ -2355,9 +2345,11 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
 	location.objectid = BTRFS_UUID_TREE_OBJECTID;
 	root = btrfs_read_tree_root(tree_root, &location);
 	if (IS_ERR(root)) {
-		ret = PTR_ERR(root);
-		if (ret != -ENOENT)
-			goto out;
+		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+			ret = PTR_ERR(root);
+			if (ret != -ENOENT)
+				goto out;
+		}
 	} else {
 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
 		fs_info->uuid_root = root;
@@ -2367,11 +2359,14 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
 		location.objectid = BTRFS_FREE_SPACE_TREE_OBJECTID;
 		root = btrfs_read_tree_root(tree_root, &location);
 		if (IS_ERR(root)) {
-			ret = PTR_ERR(root);
-			goto out;
+			if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+				ret = PTR_ERR(root);
+				goto out;
+			}
+		}  else {
+			set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+			fs_info->free_space_root = root;
 		}
-		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
-		fs_info->free_space_root = root;
 	}
 
 	return 0;
@@ -2627,6 +2622,7 @@ static int __cold init_tree_roots(struct btrfs_fs_info *fs_info)
 		generation = btrfs_super_generation(sb);
 		level = btrfs_super_root_level(sb);
 		tree_root->node = read_tree_block(fs_info, btrfs_super_root(sb),
+						  BTRFS_ROOT_TREE_OBJECTID,
 						  generation, level, NULL);
 		if (IS_ERR(tree_root->node)) {
 			handle_error = true;
@@ -2791,6 +2787,7 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info)
 	/* Usable values until the real ones are cached from the superblock */
 	fs_info->nodesize = 4096;
 	fs_info->sectorsize = 4096;
+	fs_info->sectorsize_bits = ilog2(4096);
 	fs_info->stripesize = 4096;
 
 	spin_lock_init(&fs_info->swapfile_pins_lock);
@@ -2873,6 +2870,109 @@ static int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
 	return 0;
 }
 
+/*
+ * Some options only have meaning at mount time and shouldn't persist across
+ * remounts, or be displayed. Clear these at the end of mount and remount
+ * code paths.
+ */
+void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)
+{
+	btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
+	btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE);
+}
+
+/*
+ * Mounting logic specific to read-write file systems. Shared by open_ctree
+ * and btrfs_remount when remounting from read-only to read-write.
+ */
+int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info)
+{
+	int ret;
+	const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
+	bool clear_free_space_tree = false;
+
+	if (btrfs_test_opt(fs_info, CLEAR_CACHE) &&
+	    btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
+		clear_free_space_tree = true;
+	} else if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
+		   !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID)) {
+		btrfs_warn(fs_info, "free space tree is invalid");
+		clear_free_space_tree = true;
+	}
+
+	if (clear_free_space_tree) {
+		btrfs_info(fs_info, "clearing free space tree");
+		ret = btrfs_clear_free_space_tree(fs_info);
+		if (ret) {
+			btrfs_warn(fs_info,
+				   "failed to clear free space tree: %d", ret);
+			goto out;
+		}
+	}
+
+	ret = btrfs_cleanup_fs_roots(fs_info);
+	if (ret)
+		goto out;
+
+	down_read(&fs_info->cleanup_work_sem);
+	if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
+	    (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
+		up_read(&fs_info->cleanup_work_sem);
+		goto out;
+	}
+	up_read(&fs_info->cleanup_work_sem);
+
+	mutex_lock(&fs_info->cleaner_mutex);
+	ret = btrfs_recover_relocation(fs_info->tree_root);
+	mutex_unlock(&fs_info->cleaner_mutex);
+	if (ret < 0) {
+		btrfs_warn(fs_info, "failed to recover relocation: %d", ret);
+		goto out;
+	}
+
+	if (btrfs_test_opt(fs_info, FREE_SPACE_TREE) &&
+	    !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
+		btrfs_info(fs_info, "creating free space tree");
+		ret = btrfs_create_free_space_tree(fs_info);
+		if (ret) {
+			btrfs_warn(fs_info,
+				"failed to create free space tree: %d", ret);
+			goto out;
+		}
+	}
+
+	if (cache_opt != btrfs_free_space_cache_v1_active(fs_info)) {
+		ret = btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
+		if (ret)
+			goto out;
+	}
+
+	ret = btrfs_resume_balance_async(fs_info);
+	if (ret)
+		goto out;
+
+	ret = btrfs_resume_dev_replace_async(fs_info);
+	if (ret) {
+		btrfs_warn(fs_info, "failed to resume dev_replace");
+		goto out;
+	}
+
+	btrfs_qgroup_rescan_resume(fs_info);
+
+	if (!fs_info->uuid_root) {
+		btrfs_info(fs_info, "creating UUID tree");
+		ret = btrfs_create_uuid_tree(fs_info);
+		if (ret) {
+			btrfs_warn(fs_info,
+				   "failed to create the UUID tree %d", ret);
+			goto out;
+		}
+	}
+
+out:
+	return ret;
+}
+
 int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_devices,
 		      char *options)
 {
@@ -2888,7 +2988,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	struct btrfs_root *chunk_root;
 	int ret;
 	int err = -EINVAL;
-	int clear_free_space_tree = 0;
 	int level;
 
 	ret = init_mount_fs_info(fs_info, sb);
@@ -3035,6 +3134,8 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	if (features & BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)
 		btrfs_info(fs_info, "has skinny extents");
 
+	fs_info->zoned = (features & BTRFS_FEATURE_INCOMPAT_ZONED);
+
 	/*
 	 * flag our filesystem as having big metadata blocks if
 	 * they are bigger than the page size
@@ -3055,6 +3156,9 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	/* Cache block sizes */
 	fs_info->nodesize = nodesize;
 	fs_info->sectorsize = sectorsize;
+	fs_info->sectorsize_bits = ilog2(sectorsize);
+	fs_info->csum_size = btrfs_super_csum_size(disk_super);
+	fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size;
 	fs_info->stripesize = stripesize;
 
 	/*
@@ -3111,6 +3215,7 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 
 	chunk_root->node = read_tree_block(fs_info,
 					   btrfs_super_chunk_root(disk_super),
+					   BTRFS_CHUNK_TREE_OBJECTID,
 					   generation, level, NULL);
 	if (IS_ERR(chunk_root->node) ||
 	    !extent_buffer_uptodate(chunk_root->node)) {
@@ -3134,11 +3239,13 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	}
 
 	/*
-	 * Keep the devid that is marked to be the target device for the
-	 * device replace procedure
+	 * At this point we know all the devices that make this filesystem,
+	 * including the seed devices but we don't know yet if the replace
+	 * target is required. So free devices that are not part of this
+	 * filesystem but skip the replace traget device which is checked
+	 * below in btrfs_init_dev_replace().
 	 */
-	btrfs_free_extra_devids(fs_devices, 0);
-
+	btrfs_free_extra_devids(fs_devices);
 	if (!fs_devices->latest_bdev) {
 		btrfs_err(fs_info, "failed to read devices");
 		goto fail_tree_roots;
@@ -3185,7 +3292,12 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 		goto fail_block_groups;
 	}
 
-	btrfs_free_extra_devids(fs_devices, 1);
+	ret = btrfs_check_zoned_mode(fs_info);
+	if (ret) {
+		btrfs_err(fs_info, "failed to initialize zoned mode: %d",
+			  ret);
+		goto fail_block_groups;
+	}
 
 	ret = btrfs_sysfs_add_fsid(fs_devices);
 	if (ret) {
@@ -3275,22 +3387,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	if (ret)
 		goto fail_qgroup;
 
-	if (!sb_rdonly(sb)) {
-		ret = btrfs_cleanup_fs_roots(fs_info);
-		if (ret)
-			goto fail_qgroup;
-
-		mutex_lock(&fs_info->cleaner_mutex);
-		ret = btrfs_recover_relocation(tree_root);
-		mutex_unlock(&fs_info->cleaner_mutex);
-		if (ret < 0) {
-			btrfs_warn(fs_info, "failed to recover relocation: %d",
-					ret);
-			err = -EINVAL;
-			goto fail_qgroup;
-		}
-	}
-
 	fs_info->fs_root = btrfs_get_fs_root(fs_info, BTRFS_FS_TREE_OBJECTID, true);
 	if (IS_ERR(fs_info->fs_root)) {
 		err = PTR_ERR(fs_info->fs_root);
@@ -3300,78 +3396,18 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	}
 
 	if (sb_rdonly(sb))
-		return 0;
-
-	if (btrfs_test_opt(fs_info, CLEAR_CACHE) &&
-	    btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
-		clear_free_space_tree = 1;
-	} else if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
-		   !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID)) {
-		btrfs_warn(fs_info, "free space tree is invalid");
-		clear_free_space_tree = 1;
-	}
-
-	if (clear_free_space_tree) {
-		btrfs_info(fs_info, "clearing free space tree");
-		ret = btrfs_clear_free_space_tree(fs_info);
-		if (ret) {
-			btrfs_warn(fs_info,
-				   "failed to clear free space tree: %d", ret);
-			close_ctree(fs_info);
-			return ret;
-		}
-	}
-
-	if (btrfs_test_opt(fs_info, FREE_SPACE_TREE) &&
-	    !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
-		btrfs_info(fs_info, "creating free space tree");
-		ret = btrfs_create_free_space_tree(fs_info);
-		if (ret) {
-			btrfs_warn(fs_info,
-				"failed to create free space tree: %d", ret);
-			close_ctree(fs_info);
-			return ret;
-		}
-	}
-
-	down_read(&fs_info->cleanup_work_sem);
-	if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
-	    (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
-		up_read(&fs_info->cleanup_work_sem);
-		close_ctree(fs_info);
-		return ret;
-	}
-	up_read(&fs_info->cleanup_work_sem);
+		goto clear_oneshot;
 
-	ret = btrfs_resume_balance_async(fs_info);
-	if (ret) {
-		btrfs_warn(fs_info, "failed to resume balance: %d", ret);
-		close_ctree(fs_info);
-		return ret;
-	}
-
-	ret = btrfs_resume_dev_replace_async(fs_info);
+	ret = btrfs_start_pre_rw_mount(fs_info);
 	if (ret) {
-		btrfs_warn(fs_info, "failed to resume device replace: %d", ret);
 		close_ctree(fs_info);
 		return ret;
 	}
-
-	btrfs_qgroup_rescan_resume(fs_info);
 	btrfs_discard_resume(fs_info);
 
-	if (!fs_info->uuid_root) {
-		btrfs_info(fs_info, "creating UUID tree");
-		ret = btrfs_create_uuid_tree(fs_info);
-		if (ret) {
-			btrfs_warn(fs_info,
-				"failed to create the UUID tree: %d", ret);
-			close_ctree(fs_info);
-			return ret;
-		}
-	} else if (btrfs_test_opt(fs_info, RESCAN_UUID_TREE) ||
-		   fs_info->generation !=
-				btrfs_super_uuid_tree_generation(disk_super)) {
+	if (fs_info->uuid_root &&
+	    (btrfs_test_opt(fs_info, RESCAN_UUID_TREE) ||
+	     fs_info->generation != btrfs_super_uuid_tree_generation(disk_super))) {
 		btrfs_info(fs_info, "checking UUID tree");
 		ret = btrfs_check_uuid_tree(fs_info);
 		if (ret) {
@@ -3381,14 +3417,11 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 			return ret;
 		}
 	}
-	set_bit(BTRFS_FS_OPEN, &fs_info->flags);
 
-	/*
-	 * backuproot only affect mount behavior, and if open_ctree succeeded,
-	 * no need to keep the flag
-	 */
-	btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
+	set_bit(BTRFS_FS_OPEN, &fs_info->flags);
 
+clear_oneshot:
+	btrfs_clear_oneshot_options(fs_info);
 	return 0;
 
 fail_qgroup:
@@ -3469,10 +3502,17 @@ struct btrfs_super_block *btrfs_read_dev_one_super(struct block_device *bdev,
 {
 	struct btrfs_super_block *super;
 	struct page *page;
-	u64 bytenr;
+	u64 bytenr, bytenr_orig;
 	struct address_space *mapping = bdev->bd_inode->i_mapping;
+	int ret;
+
+	bytenr_orig = btrfs_sb_offset(copy_num);
+	ret = btrfs_sb_log_location_bdev(bdev, copy_num, READ, &bytenr);
+	if (ret == -ENOENT)
+		return ERR_PTR(-EINVAL);
+	else if (ret)
+		return ERR_PTR(ret);
 
-	bytenr = btrfs_sb_offset(copy_num);
 	if (bytenr + BTRFS_SUPER_INFO_SIZE >= i_size_read(bdev->bd_inode))
 		return ERR_PTR(-EINVAL);
 
@@ -3486,7 +3526,7 @@ struct btrfs_super_block *btrfs_read_dev_one_super(struct block_device *bdev,
 		return ERR_PTR(-ENODATA);
 	}
 
-	if (btrfs_super_bytenr(super) != bytenr) {
+	if (btrfs_super_bytenr(super) != bytenr_orig) {
 		btrfs_release_disk_super(super);
 		return ERR_PTR(-EINVAL);
 	}
@@ -3541,7 +3581,8 @@ static int write_dev_supers(struct btrfs_device *device,
 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 	int i;
 	int errors = 0;
-	u64 bytenr;
+	int ret;
+	u64 bytenr, bytenr_orig;
 
 	if (max_mirrors == 0)
 		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
@@ -3553,12 +3594,22 @@ static int write_dev_supers(struct btrfs_device *device,
 		struct bio *bio;
 		struct btrfs_super_block *disk_super;
 
-		bytenr = btrfs_sb_offset(i);
+		bytenr_orig = btrfs_sb_offset(i);
+		ret = btrfs_sb_log_location(device, i, WRITE, &bytenr);
+		if (ret == -ENOENT) {
+			continue;
+		} else if (ret < 0) {
+			btrfs_err(device->fs_info,
+				"couldn't get super block location for mirror %d",
+				i);
+			errors++;
+			continue;
+		}
 		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
 		    device->commit_total_bytes)
 			break;
 
-		btrfs_set_super_bytenr(sb, bytenr);
+		btrfs_set_super_bytenr(sb, bytenr_orig);
 
 		crypto_shash_digest(shash, (const char *)sb + BTRFS_CSUM_SIZE,
 				    BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE,
@@ -3603,6 +3654,7 @@ static int write_dev_supers(struct btrfs_device *device,
 			bio->bi_opf |= REQ_FUA;
 
 		btrfsic_submit_bio(bio);
+		btrfs_advance_sb_log(device, i);
 	}
 	return errors < i ? 0 : -1;
 }
@@ -3619,6 +3671,7 @@ static int wait_dev_supers(struct btrfs_device *device, int max_mirrors)
 	int i;
 	int errors = 0;
 	bool primary_failed = false;
+	int ret;
 	u64 bytenr;
 
 	if (max_mirrors == 0)
@@ -3627,7 +3680,15 @@ static int wait_dev_supers(struct btrfs_device *device, int max_mirrors)
 	for (i = 0; i < max_mirrors; i++) {
 		struct page *page;
 
-		bytenr = btrfs_sb_offset(i);
+		ret = btrfs_sb_log_location(device, i, READ, &bytenr);
+		if (ret == -ENOENT) {
+			break;
+		} else if (ret < 0) {
+			errors++;
+			if (i == 0)
+				primary_failed = true;
+			continue;
+		}
 		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
 		    device->commit_total_bytes)
 			break;
@@ -3941,14 +4002,6 @@ void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
 		}
 	}
 
-	if (root->free_ino_pinned)
-		__btrfs_remove_free_space_cache(root->free_ino_pinned);
-	if (root->free_ino_ctl)
-		__btrfs_remove_free_space_cache(root->free_ino_ctl);
-	if (root->ino_cache_inode) {
-		iput(root->ino_cache_inode);
-		root->ino_cache_inode = NULL;
-	}
 	if (drop_ref)
 		btrfs_put_root(root);
 }
@@ -4171,8 +4224,7 @@ int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
 
 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
 {
-	struct btrfs_fs_info *fs_info;
-	struct btrfs_root *root;
+	struct btrfs_fs_info *fs_info = buf->fs_info;
 	u64 transid = btrfs_header_generation(buf);
 	int was_dirty;
 
@@ -4185,8 +4237,6 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
 	if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &buf->bflags)))
 		return;
 #endif
-	root = BTRFS_I(buf->pages[0]->mapping->host)->root;
-	fs_info = root->fs_info;
 	btrfs_assert_tree_locked(buf);
 	if (transid != fs_info->generation)
 		WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, found %llu running %llu\n",
@@ -4691,3 +4741,58 @@ static int btrfs_cleanup_transaction(struct btrfs_fs_info *fs_info)
 
 	return 0;
 }
+
+int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
+{
+	struct btrfs_path *path;
+	int ret;
+	struct extent_buffer *l;
+	struct btrfs_key search_key;
+	struct btrfs_key found_key;
+	int slot;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
+	search_key.type = -1;
+	search_key.offset = (u64)-1;
+	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+	if (ret < 0)
+		goto error;
+	BUG_ON(ret == 0); /* Corruption */
+	if (path->slots[0] > 0) {
+		slot = path->slots[0] - 1;
+		l = path->nodes[0];
+		btrfs_item_key_to_cpu(l, &found_key, slot);
+		*objectid = max_t(u64, found_key.objectid,
+				  BTRFS_FIRST_FREE_OBJECTID - 1);
+	} else {
+		*objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
+	}
+	ret = 0;
+error:
+	btrfs_free_path(path);
+	return ret;
+}
+
+int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
+{
+	int ret;
+	mutex_lock(&root->objectid_mutex);
+
+	if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
+		btrfs_warn(root->fs_info,
+			   "the objectid of root %llu reaches its highest value",
+			   root->root_key.objectid);
+		ret = -ENOSPC;
+		goto out;
+	}
+
+	*objectid = ++root->highest_objectid;
+	ret = 0;
+out:
+	mutex_unlock(&root->objectid_mutex);
+	return ret;
+}