Merge branch 'cleanups-post-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.1

Signed-off-by: Chris Mason <clm@fb.com>

Conflicts:
	fs/btrfs/disk-io.c

25 files changed, 384 insertions, 350 deletions

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 4dabeb8..df9932b 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -87,7 +87,7 @@ BTRFS_WORK_HELPER(scrubwrc_helper);
 BTRFS_WORK_HELPER(scrubnc_helper);
 
 static struct __btrfs_workqueue *
-__btrfs_alloc_workqueue(const char *name, int flags, int max_active,
+__btrfs_alloc_workqueue(const char *name, unsigned int flags, int max_active,
 			 int thresh)
 {
 	struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
@@ -132,7 +132,7 @@ static inline void
 __btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
 
 struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
-					      int flags,
+					      unsigned int flags,
 					      int max_active,
 					      int thresh)
 {
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index e386c29..ec2ee47 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -66,7 +66,7 @@ BTRFS_WORK_HELPER_PROTO(scrubwrc_helper);
 BTRFS_WORK_HELPER_PROTO(scrubnc_helper);
 
 struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
-					      int flags,
+					      unsigned int flags,
 					      int max_active,
 					      int thresh);
 void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t helper,
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 089d6fa..ce7dec8 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -3241,8 +3241,5 @@ void btrfsic_unmount(struct btrfs_root *root,
 
 	mutex_unlock(&btrfsic_mutex);
 
-	if (is_vmalloc_addr(state))
-		vfree(state);
-	else
-		kfree(state);
+	kvfree(state);
 }
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index ecacb7a..ce62324 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -750,7 +750,7 @@ static int comp_num_workspace[BTRFS_COMPRESS_TYPES];
 static atomic_t comp_alloc_workspace[BTRFS_COMPRESS_TYPES];
 static wait_queue_head_t comp_workspace_wait[BTRFS_COMPRESS_TYPES];
 
-static struct btrfs_compress_op *btrfs_compress_op[] = {
+static const struct btrfs_compress_op * const btrfs_compress_op[] = {
 	&btrfs_zlib_compress,
 	&btrfs_lzo_compress,
 };
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index d181f70..13a4dc0 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -77,7 +77,7 @@ struct btrfs_compress_op {
 			  size_t srclen, size_t destlen);
 };
 
-extern struct btrfs_compress_op btrfs_zlib_compress;
-extern struct btrfs_compress_op btrfs_lzo_compress;
+extern const struct btrfs_compress_op btrfs_zlib_compress;
+extern const struct btrfs_compress_op btrfs_lzo_compress;
 
 #endif
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 1c7e913..0f11ebc 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1072,7 +1072,7 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
 			ret = btrfs_dec_ref(trans, root, buf, 1);
 			BUG_ON(ret); /* -ENOMEM */
 		}
-		clean_tree_block(trans, root, buf);
+		clean_tree_block(trans, root->fs_info, buf);
 		*last_ref = 1;
 	}
 	return 0;
@@ -1677,7 +1677,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 			continue;
 		}
 
-		cur = btrfs_find_tree_block(root, blocknr);
+		cur = btrfs_find_tree_block(root->fs_info, blocknr);
 		if (cur)
 			uptodate = btrfs_buffer_uptodate(cur, gen, 0);
 		else
@@ -1942,7 +1942,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 
 		path->locks[level] = 0;
 		path->nodes[level] = NULL;
-		clean_tree_block(trans, root, mid);
+		clean_tree_block(trans, root->fs_info, mid);
 		btrfs_tree_unlock(mid);
 		/* once for the path */
 		free_extent_buffer(mid);
@@ -1996,7 +1996,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		if (wret < 0 && wret != -ENOSPC)
 			ret = wret;
 		if (btrfs_header_nritems(right) == 0) {
-			clean_tree_block(trans, root, right);
+			clean_tree_block(trans, root->fs_info, right);
 			btrfs_tree_unlock(right);
 			del_ptr(root, path, level + 1, pslot + 1);
 			root_sub_used(root, right->len);
@@ -2040,7 +2040,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		BUG_ON(wret == 1);
 	}
 	if (btrfs_header_nritems(mid) == 0) {
-		clean_tree_block(trans, root, mid);
+		clean_tree_block(trans, root->fs_info, mid);
 		btrfs_tree_unlock(mid);
 		del_ptr(root, path, level + 1, pslot);
 		root_sub_used(root, mid->len);
@@ -2258,7 +2258,7 @@ static void reada_for_search(struct btrfs_root *root,
 
 	search = btrfs_node_blockptr(node, slot);
 	blocksize = root->nodesize;
-	eb = btrfs_find_tree_block(root, search);
+	eb = btrfs_find_tree_block(root->fs_info, search);
 	if (eb) {
 		free_extent_buffer(eb);
 		return;
@@ -2318,7 +2318,7 @@ static noinline void reada_for_balance(struct btrfs_root *root,
 	if (slot > 0) {
 		block1 = btrfs_node_blockptr(parent, slot - 1);
 		gen = btrfs_node_ptr_generation(parent, slot - 1);
-		eb = btrfs_find_tree_block(root, block1);
+		eb = btrfs_find_tree_block(root->fs_info, block1);
 		/*
 		 * if we get -eagain from btrfs_buffer_uptodate, we
 		 * don't want to return eagain here.  That will loop
@@ -2331,7 +2331,7 @@ static noinline void reada_for_balance(struct btrfs_root *root,
 	if (slot + 1 < nritems) {
 		block2 = btrfs_node_blockptr(parent, slot + 1);
 		gen = btrfs_node_ptr_generation(parent, slot + 1);
-		eb = btrfs_find_tree_block(root, block2);
+		eb = btrfs_find_tree_block(root->fs_info, block2);
 		if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
 			block2 = 0;
 		free_extent_buffer(eb);
@@ -2449,7 +2449,7 @@ read_block_for_search(struct btrfs_trans_handle *trans,
 	blocknr = btrfs_node_blockptr(b, slot);
 	gen = btrfs_node_ptr_generation(b, slot);
 
-	tmp = btrfs_find_tree_block(root, blocknr);
+	tmp = btrfs_find_tree_block(root->fs_info, blocknr);
 	if (tmp) {
 		/* first we do an atomic uptodate check */
 		if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
@@ -3125,7 +3125,8 @@ again:
  * higher levels
  *
  */
-static void fixup_low_keys(struct btrfs_root *root, struct btrfs_path *path,
+static void fixup_low_keys(struct btrfs_fs_info *fs_info,
+			   struct btrfs_path *path,
 			   struct btrfs_disk_key *key, int level)
 {
 	int i;
@@ -3136,7 +3137,7 @@ static void fixup_low_keys(struct btrfs_root *root, struct btrfs_path *path,
 		if (!path->nodes[i])
 			break;
 		t = path->nodes[i];
-		tree_mod_log_set_node_key(root->fs_info, t, tslot, 1);
+		tree_mod_log_set_node_key(fs_info, t, tslot, 1);
 		btrfs_set_node_key(t, key, tslot);
 		btrfs_mark_buffer_dirty(path->nodes[i]);
 		if (tslot != 0)
@@ -3150,7 +3151,8 @@ static void fixup_low_keys(struct btrfs_root *root, struct btrfs_path *path,
  * This function isn't completely safe. It's the caller's responsibility
  * that the new key won't break the order
  */
-void btrfs_set_item_key_safe(struct btrfs_root *root, struct btrfs_path *path,
+void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info,
+			     struct btrfs_path *path,
 			     struct btrfs_key *new_key)
 {
 	struct btrfs_disk_key disk_key;
@@ -3172,7 +3174,7 @@ void btrfs_set_item_key_safe(struct btrfs_root *root, struct btrfs_path *path,
 	btrfs_set_item_key(eb, &disk_key, slot);
 	btrfs_mark_buffer_dirty(eb);
 	if (slot == 0)
-		fixup_low_keys(root, path, &disk_key, 1);
+		fixup_low_keys(fs_info, path, &disk_key, 1);
 }
 
 /*
@@ -3691,7 +3693,7 @@ static noinline int __push_leaf_right(struct btrfs_trans_handle *trans,
 	if (left_nritems)
 		btrfs_mark_buffer_dirty(left);
 	else
-		clean_tree_block(trans, root, left);
+		clean_tree_block(trans, root->fs_info, left);
 
 	btrfs_mark_buffer_dirty(right);
 
@@ -3703,7 +3705,7 @@ static noinline int __push_leaf_right(struct btrfs_trans_handle *trans,
 	if (path->slots[0] >= left_nritems) {
 		path->slots[0] -= left_nritems;
 		if (btrfs_header_nritems(path->nodes[0]) == 0)
-			clean_tree_block(trans, root, path->nodes[0]);
+			clean_tree_block(trans, root->fs_info, path->nodes[0]);
 		btrfs_tree_unlock(path->nodes[0]);
 		free_extent_buffer(path->nodes[0]);
 		path->nodes[0] = right;
@@ -3927,10 +3929,10 @@ static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
 	if (right_nritems)
 		btrfs_mark_buffer_dirty(right);
 	else
-		clean_tree_block(trans, root, right);
+		clean_tree_block(trans, root->fs_info, right);
 
 	btrfs_item_key(right, &disk_key, 0);
-	fixup_low_keys(root, path, &disk_key, 1);
+	fixup_low_keys(root->fs_info, path, &disk_key, 1);
 
 	/* then fixup the leaf pointer in the path */
 	if (path->slots[0] < push_items) {
@@ -4167,6 +4169,7 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
 	int mid;
 	int slot;
 	struct extent_buffer *right;
+	struct btrfs_fs_info *fs_info = root->fs_info;
 	int ret = 0;
 	int wret;
 	int split;
@@ -4270,10 +4273,10 @@ again:
 	btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
 	btrfs_set_header_owner(right, root->root_key.objectid);
 	btrfs_set_header_level(right, 0);
-	write_extent_buffer(right, root->fs_info->fsid,
+	write_extent_buffer(right, fs_info->fsid,
 			    btrfs_header_fsid(), BTRFS_FSID_SIZE);
 
-	write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
+	write_extent_buffer(right, fs_info->chunk_tree_uuid,
 			    btrfs_header_chunk_tree_uuid(right),
 			    BTRFS_UUID_SIZE);
 
@@ -4296,7 +4299,7 @@ again:
 			path->nodes[0] = right;
 			path->slots[0] = 0;
 			if (path->slots[1] == 0)
-				fixup_low_keys(root, path, &disk_key, 1);
+				fixup_low_keys(fs_info, path, &disk_key, 1);
 		}
 		btrfs_mark_buffer_dirty(right);
 		return ret;
@@ -4614,7 +4617,7 @@ void btrfs_truncate_item(struct btrfs_root *root, struct btrfs_path *path,
 		btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
 		btrfs_set_item_key(leaf, &disk_key, slot);
 		if (slot == 0)
-			fixup_low_keys(root, path, &disk_key, 1);
+			fixup_low_keys(root->fs_info, path, &disk_key, 1);
 	}
 
 	item = btrfs_item_nr(slot);
@@ -4715,7 +4718,7 @@ void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
 
 	if (path->slots[0] == 0) {
 		btrfs_cpu_key_to_disk(&disk_key, cpu_key);
-		fixup_low_keys(root, path, &disk_key, 1);
+		fixup_low_keys(root->fs_info, path, &disk_key, 1);
 	}
 	btrfs_unlock_up_safe(path, 1);
 
@@ -4887,7 +4890,7 @@ static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
 		struct btrfs_disk_key disk_key;
 
 		btrfs_node_key(parent, &disk_key, 0);
-		fixup_low_keys(root, path, &disk_key, level + 1);
+		fixup_low_keys(root->fs_info, path, &disk_key, level + 1);
 	}
 	btrfs_mark_buffer_dirty(parent);
 }
@@ -4980,7 +4983,7 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 			btrfs_set_header_level(leaf, 0);
 		} else {
 			btrfs_set_path_blocking(path);
-			clean_tree_block(trans, root, leaf);
+			clean_tree_block(trans, root->fs_info, leaf);
 			btrfs_del_leaf(trans, root, path, leaf);
 		}
 	} else {
@@ -4989,7 +4992,7 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 			struct btrfs_disk_key disk_key;
 
 			btrfs_item_key(leaf, &disk_key, 0);
-			fixup_low_keys(root, path, &disk_key, 1);
+			fixup_low_keys(root->fs_info, path, &disk_key, 1);
 		}
 
 		/* delete the leaf if it is mostly empty */
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f8548d6..95944b8 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3488,7 +3488,8 @@ int btrfs_previous_item(struct btrfs_root *root,
 			int type);
 int btrfs_previous_extent_item(struct btrfs_root *root,
 			struct btrfs_path *path, u64 min_objectid);
-void btrfs_set_item_key_safe(struct btrfs_root *root, struct btrfs_path *path,
+void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info,
+			     struct btrfs_path *path,
 			     struct btrfs_key *new_key);
 struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
 struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 82f0c7c..cde698a 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1383,7 +1383,7 @@ out:
 
 
 static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
-				     struct btrfs_root *root, int nr)
+				     struct btrfs_fs_info *fs_info, int nr)
 {
 	struct btrfs_async_delayed_work *async_work;
 
@@ -1399,7 +1399,7 @@ static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
 			btrfs_async_run_delayed_root, NULL, NULL);
 	async_work->nr = nr;
 
-	btrfs_queue_work(root->fs_info->delayed_workers, &async_work->work);
+	btrfs_queue_work(fs_info->delayed_workers, &async_work->work);
 	return 0;
 }
 
@@ -1426,6 +1426,7 @@ static int could_end_wait(struct btrfs_delayed_root *delayed_root, int seq)
 void btrfs_balance_delayed_items(struct btrfs_root *root)
 {
 	struct btrfs_delayed_root *delayed_root;
+	struct btrfs_fs_info *fs_info = root->fs_info;
 
 	delayed_root = btrfs_get_delayed_root(root);
 
@@ -1438,7 +1439,7 @@ void btrfs_balance_delayed_items(struct btrfs_root *root)
 
 		seq = atomic_read(&delayed_root->items_seq);
 
-		ret = btrfs_wq_run_delayed_node(delayed_root, root, 0);
+		ret = btrfs_wq_run_delayed_node(delayed_root, fs_info, 0);
 		if (ret)
 			return;
 
@@ -1447,7 +1448,7 @@ void btrfs_balance_delayed_items(struct btrfs_root *root)
 		return;
 	}
 
-	btrfs_wq_run_delayed_node(delayed_root, root, BTRFS_DELAYED_BATCH);
+	btrfs_wq_run_delayed_node(delayed_root, fs_info, BTRFS_DELAYED_BATCH);
 }
 
 /* Will return 0 or -ENOMEM */
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 6aaaf98..23c49ab 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -54,7 +54,7 @@
 #include <asm/cpufeature.h>
 #endif
 
-static struct extent_io_ops btree_extent_io_ops;
+static const struct extent_io_ops btree_extent_io_ops;
 static void end_workqueue_fn(struct btrfs_work *work);
 static void free_fs_root(struct btrfs_root *root);
 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
@@ -274,10 +274,11 @@ void btrfs_csum_final(u32 crc, char *result)
  * compute the csum for a btree block, and either verify it or write it
  * into the csum field of the block.
  */
-static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
+static int csum_tree_block(struct btrfs_fs_info *fs_info,
+			   struct extent_buffer *buf,
 			   int verify)
 {
-	u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
+	u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 	char *result = NULL;
 	unsigned long len;
 	unsigned long cur_len;
@@ -321,7 +322,7 @@ static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 			printk_ratelimited(KERN_WARNING
 				"BTRFS: %s checksum verify failed on %llu wanted %X found %X "
 				"level %d\n",
-				root->fs_info->sb->s_id, buf->start,
+				fs_info->sb->s_id, buf->start,
 				val, found, btrfs_header_level(buf));
 			if (result != (char *)&inline_result)
 				kfree(result);
@@ -501,7 +502,7 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root,
  * we only fill in the checksum field in the first page of a multi-page block
  */
 
-static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
+static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page)
 {
 	u64 start = page_offset(page);
 	u64 found_start;
@@ -513,14 +514,14 @@ static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 	found_start = btrfs_header_bytenr(eb);
 	if (WARN_ON(found_start != start || !PageUptodate(page)))
 		return 0;
-	csum_tree_block(root, eb, 0);
+	csum_tree_block(fs_info, eb, 0);
 	return 0;
 }
 
-static int check_tree_block_fsid(struct btrfs_root *root,
+static int check_tree_block_fsid(struct btrfs_fs_info *fs_info,
 				 struct extent_buffer *eb)
 {
-	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
+	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 	u8 fsid[BTRFS_UUID_SIZE];
 	int ret = 1;
 
@@ -640,7 +641,7 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
 		ret = -EIO;
 		goto err;
 	}
-	if (check_tree_block_fsid(root, eb)) {
+	if (check_tree_block_fsid(root->fs_info, eb)) {
 		printk_ratelimited(KERN_ERR "BTRFS (device %s): bad fsid on block %llu\n",
 			       eb->fs_info->sb->s_id, eb->start);
 		ret = -EIO;
@@ -657,7 +658,7 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
 	btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
 				       eb, found_level);
 
-	ret = csum_tree_block(root, eb, 1);
+	ret = csum_tree_block(root->fs_info, eb, 1);
 	if (ret) {
 		ret = -EIO;
 		goto err;
@@ -882,7 +883,7 @@ static int btree_csum_one_bio(struct bio *bio)
 
 	bio_for_each_segment_all(bvec, bio, i) {
 		root = BTRFS_I(bvec->bv_page->mapping->host)->root;
-		ret = csum_dirty_buffer(root, bvec->bv_page);
+		ret = csum_dirty_buffer(root->fs_info, bvec->bv_page);
 		if (ret)
 			break;
 	}
@@ -1119,10 +1120,10 @@ int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr,
 	return 0;
 }
 
-struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
+struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info,
 					    u64 bytenr)
 {
-	return find_extent_buffer(root->fs_info, bytenr);
+	return find_extent_buffer(fs_info, bytenr);
 }
 
 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
@@ -1165,11 +1166,10 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 
 }
 
-void clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+void clean_tree_block(struct btrfs_trans_handle *trans,
+		      struct btrfs_fs_info *fs_info,
 		      struct extent_buffer *buf)
 {
-	struct btrfs_fs_info *fs_info = root->fs_info;
-
 	if (btrfs_header_generation(buf) ==
 	    fs_info->running_transaction->transid) {
 		btrfs_assert_tree_locked(buf);
@@ -2146,6 +2146,267 @@ void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info)
 	}
 }
 
+static void btrfs_init_scrub(struct btrfs_fs_info *fs_info)
+{
+	mutex_init(&fs_info->scrub_lock);
+	atomic_set(&fs_info->scrubs_running, 0);
+	atomic_set(&fs_info->scrub_pause_req, 0);
+	atomic_set(&fs_info->scrubs_paused, 0);
+	atomic_set(&fs_info->scrub_cancel_req, 0);
+	init_waitqueue_head(&fs_info->scrub_pause_wait);
+	fs_info->scrub_workers_refcnt = 0;
+}
+
+static void btrfs_init_balance(struct btrfs_fs_info *fs_info)
+{
+	spin_lock_init(&fs_info->balance_lock);
+	mutex_init(&fs_info->balance_mutex);
+	atomic_set(&fs_info->balance_running, 0);
+	atomic_set(&fs_info->balance_pause_req, 0);
+	atomic_set(&fs_info->balance_cancel_req, 0);
+	fs_info->balance_ctl = NULL;
+	init_waitqueue_head(&fs_info->balance_wait_q);
+}
+
+static void btrfs_init_btree_inode(struct btrfs_fs_info *fs_info,
+				   struct btrfs_root *tree_root)
+{
+	fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
+	set_nlink(fs_info->btree_inode, 1);
+	/*
+	 * we set the i_size on the btree inode to the max possible int.
+	 * the real end of the address space is determined by all of
+	 * the devices in the system
+	 */
+	fs_info->btree_inode->i_size = OFFSET_MAX;
+	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
+
+	RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
+	extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
+			     fs_info->btree_inode->i_mapping);
+	BTRFS_I(fs_info->btree_inode)->io_tree.track_uptodate = 0;
+	extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
+
+	BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
+
+	BTRFS_I(fs_info->btree_inode)->root = tree_root;
+	memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
+	       sizeof(struct btrfs_key));
+	set_bit(BTRFS_INODE_DUMMY,
+		&BTRFS_I(fs_info->btree_inode)->runtime_flags);
+	btrfs_insert_inode_hash(fs_info->btree_inode);
+}
+
+static void btrfs_init_dev_replace_locks(struct btrfs_fs_info *fs_info)
+{
+	fs_info->dev_replace.lock_owner = 0;
+	atomic_set(&fs_info->dev_replace.nesting_level, 0);
+	mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
+	mutex_init(&fs_info->dev_replace.lock_management_lock);
+	mutex_init(&fs_info->dev_replace.lock);
+	init_waitqueue_head(&fs_info->replace_wait);
+}
+
+static void btrfs_init_qgroup(struct btrfs_fs_info *fs_info)
+{
+	spin_lock_init(&fs_info->qgroup_lock);
+	mutex_init(&fs_info->qgroup_ioctl_lock);
+	fs_info->qgroup_tree = RB_ROOT;
+	fs_info->qgroup_op_tree = RB_ROOT;
+	INIT_LIST_HEAD(&fs_info->dirty_qgroups);
+	fs_info->qgroup_seq = 1;
+	fs_info->quota_enabled = 0;
+	fs_info->pending_quota_state = 0;
+	fs_info->qgroup_ulist = NULL;
+	mutex_init(&fs_info->qgroup_rescan_lock);
+}
+
+static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info,
+		struct btrfs_fs_devices *fs_devices)
+{
+	int max_active = fs_info->thread_pool_size;
+	unsigned int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
+
+	fs_info->workers =
+		btrfs_alloc_workqueue("worker", flags | WQ_HIGHPRI,
+				      max_active, 16);
+
+	fs_info->delalloc_workers =
+		btrfs_alloc_workqueue("delalloc", flags, max_active, 2);
+
+	fs_info->flush_workers =
+		btrfs_alloc_workqueue("flush_delalloc", flags, max_active, 0);
+
+	fs_info->caching_workers =
+		btrfs_alloc_workqueue("cache", flags, max_active, 0);
+
+	/*
+	 * a higher idle thresh on the submit workers makes it much more
+	 * likely that bios will be send down in a sane order to the
+	 * devices
+	 */
+	fs_info->submit_workers =
+		btrfs_alloc_workqueue("submit", flags,
+				      min_t(u64, fs_devices->num_devices,
+					    max_active), 64);
+
+	fs_info->fixup_workers =
+		btrfs_alloc_workqueue("fixup", flags, 1, 0);
+
+	/*
+	 * endios are largely parallel and should have a very
+	 * low idle thresh
+	 */
+	fs_info->endio_workers =
+		btrfs_alloc_workqueue("endio", flags, max_active, 4);
+	fs_info->endio_meta_workers =
+		btrfs_alloc_workqueue("endio-meta", flags, max_active, 4);
+	fs_info->endio_meta_write_workers =
+		btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
+	fs_info->endio_raid56_workers =
+		btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
+	fs_info->endio_repair_workers =
+		btrfs_alloc_workqueue("endio-repair", flags, 1, 0);
+	fs_info->rmw_workers =
+		btrfs_alloc_workqueue("rmw", flags, max_active, 2);
+	fs_info->endio_write_workers =
+		btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
+	fs_info->endio_freespace_worker =
+		btrfs_alloc_workqueue("freespace-write", flags, max_active, 0);
+	fs_info->delayed_workers =
+		btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
+	fs_info->readahead_workers =
+		btrfs_alloc_workqueue("readahead", flags, max_active, 2);
+	fs_info->qgroup_rescan_workers =
+		btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
+	fs_info->extent_workers =
+		btrfs_alloc_workqueue("extent-refs", flags,
+				      min_t(u64, fs_devices->num_devices,
+					    max_active), 8);
+
+	if (!(fs_info->workers && fs_info->delalloc_workers &&
+	      fs_info->submit_workers && fs_info->flush_workers &&
+	      fs_info->endio_workers && fs_info->endio_meta_workers &&
+	      fs_info->endio_meta_write_workers &&
+	      fs_info->endio_repair_workers &&
+	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
+	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
+	      fs_info->caching_workers && fs_info->readahead_workers &&
+	      fs_info->fixup_workers && fs_info->delayed_workers &&
+	      fs_info->extent_workers &&
+	      fs_info->qgroup_rescan_workers)) {
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int btrfs_replay_log(struct btrfs_fs_info *fs_info,
+			    struct btrfs_fs_devices *fs_devices)
+{
+	int ret;
+	struct btrfs_root *tree_root = fs_info->tree_root;
+	struct btrfs_root *log_tree_root;
+	struct btrfs_super_block *disk_super = fs_info->super_copy;
+	u64 bytenr = btrfs_super_log_root(disk_super);
+
+	if (fs_devices->rw_devices == 0) {
+		printk(KERN_WARNING "BTRFS: log replay required "
+		       "on RO media\n");
+		return -EIO;
+	}
+
+	log_tree_root = btrfs_alloc_root(fs_info);
+	if (!log_tree_root)
+		return -ENOMEM;
+
+	__setup_root(tree_root->nodesize, tree_root->sectorsize,
+			tree_root->stripesize, log_tree_root, fs_info,
+			BTRFS_TREE_LOG_OBJECTID);
+
+	log_tree_root->node = read_tree_block(tree_root, bytenr,
+			fs_info->generation + 1);
+	if (!log_tree_root->node ||
+	    !extent_buffer_uptodate(log_tree_root->node)) {
+		printk(KERN_ERR "BTRFS: failed to read log tree\n");
+		free_extent_buffer(log_tree_root->node);
+		kfree(log_tree_root);
+		return -EIO;
+	}
+	/* returns with log_tree_root freed on success */
+	ret = btrfs_recover_log_trees(log_tree_root);
+	if (ret) {
+		btrfs_error(tree_root->fs_info, ret,
+			    "Failed to recover log tree");
+		free_extent_buffer(log_tree_root->node);
+		kfree(log_tree_root);
+		return ret;
+	}
+
+	if (fs_info->sb->s_flags & MS_RDONLY) {
+		ret = btrfs_commit_super(tree_root);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int btrfs_read_roots(struct btrfs_fs_info *fs_info,
+			    struct btrfs_root *tree_root)
+{
+	struct btrfs_root *root;
+	struct btrfs_key location;
+	int ret;
+
+	location.objectid = BTRFS_EXTENT_TREE_OBJECTID;
+	location.type = BTRFS_ROOT_ITEM_KEY;
+	location.offset = 0;
+
+	root = btrfs_read_tree_root(tree_root, &location);
+	if (IS_ERR(root))
+		return PTR_ERR(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))
+		return PTR_ERR(root);
+	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))
+		return PTR_ERR(root);
+	set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+	fs_info->csum_root = root;
+
+	location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
+	root = btrfs_read_tree_root(tree_root, &location);
+	if (!IS_ERR(root)) {
+		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+		fs_info->quota_enabled = 1;
+		fs_info->pending_quota_state = 1;
+		fs_info->quota_root = root;
+	}
+
+	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)
+			return ret;
+	} else {
+		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+		fs_info->uuid_root = root;
+	}
+
+	return 0;
+}
+
 int open_ctree(struct super_block *sb,
 	       struct btrfs_fs_devices *fs_devices,
 	       char *options)
@@ -2160,21 +2421,12 @@ int open_ctree(struct super_block *sb,
 	struct btrfs_super_block *disk_super;
 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
 	struct btrfs_root *tree_root;
-	struct btrfs_root *extent_root;
-	struct btrfs_root *csum_root;
 	struct btrfs_root *chunk_root;
-	struct btrfs_root *dev_root;
-	struct btrfs_root *quota_root;
-	struct btrfs_root *uuid_root;
-	struct btrfs_root *log_tree_root;
 	int ret;
 	int err = -EINVAL;
 	int num_backups_tried = 0;
 	int backup_index = 0;
 	int max_active;
-	int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
-	bool create_uuid_tree;
-	bool check_uuid_tree;
 
 	tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
 	chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
@@ -2294,55 +2546,18 @@ int open_ctree(struct super_block *sb,
 	}
 	btrfs_init_delayed_root(fs_info->delayed_root);
 
-	mutex_init(&fs_info->scrub_lock);
-	atomic_set(&fs_info->scrubs_running, 0);
-	atomic_set(&fs_info->scrub_pause_req, 0);
-	atomic_set(&fs_info->scrubs_paused, 0);
-	atomic_set(&fs_info->scrub_cancel_req, 0);
-	init_waitqueue_head(&fs_info->replace_wait);
-	init_waitqueue_head(&fs_info->scrub_pause_wait);
-	fs_info->scrub_workers_refcnt = 0;
+	btrfs_init_scrub(fs_info);
 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 	fs_info->check_integrity_print_mask = 0;
 #endif
-
-	spin_lock_init(&fs_info->balance_lock);
-	mutex_init(&fs_info->balance_mutex);
-	atomic_set(&fs_info->balance_running, 0);
-	atomic_set(&fs_info->balance_pause_req, 0);
-	atomic_set(&fs_info->balance_cancel_req, 0);
-	fs_info->balance_ctl = NULL;
-	init_waitqueue_head(&fs_info->balance_wait_q);
+	btrfs_init_balance(fs_info);
 	btrfs_init_async_reclaim_work(&fs_info->async_reclaim_work);
 
 	sb->s_blocksize = 4096;
 	sb->s_blocksize_bits = blksize_bits(4096);
 	sb->s_bdi = &fs_info->bdi;
 
-	fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
-	set_nlink(fs_info->btree_inode, 1);
-	/*
-	 * we set the i_size on the btree inode to the max possible int.
-	 * the real end of the address space is determined by all of
-	 * the devices in the system
-	 */
-	fs_info->btree_inode->i_size = OFFSET_MAX;
-	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
-
-	RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
-	extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
-			     fs_info->btree_inode->i_mapping);
-	BTRFS_I(fs_info->btree_inode)->io_tree.track_uptodate = 0;
-	extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
-
-	BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
-
-	BTRFS_I(fs_info->btree_inode)->root = tree_root;
-	memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
-	       sizeof(struct btrfs_key));
-	set_bit(BTRFS_INODE_DUMMY,
-		&BTRFS_I(fs_info->btree_inode)->runtime_flags);
-	btrfs_insert_inode_hash(fs_info->btree_inode);
+	btrfs_init_btree_inode(fs_info, tree_root);
 
 	spin_lock_init(&fs_info->block_group_cache_lock);
 	fs_info->block_group_cache_tree = RB_ROOT;
@@ -2367,22 +2582,9 @@ int open_ctree(struct super_block *sb,
 	init_rwsem(&fs_info->cleanup_work_sem);
 	init_rwsem(&fs_info->subvol_sem);
 	sema_init(&fs_info->uuid_tree_rescan_sem, 1);
-	fs_info->dev_replace.lock_owner = 0;
-	atomic_set(&fs_info->dev_replace.nesting_level, 0);
-	mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
-	mutex_init(&fs_info->dev_replace.lock_management_lock);
-	mutex_init(&fs_info->dev_replace.lock);
 
-	spin_lock_init(&fs_info->qgroup_lock);
-	mutex_init(&fs_info->qgroup_ioctl_lock);
-	fs_info->qgroup_tree = RB_ROOT;
-	fs_info->qgroup_op_tree = RB_ROOT;
-	INIT_LIST_HEAD(&fs_info->dirty_qgroups);
-	fs_info->qgroup_seq = 1;
-	fs_info->quota_enabled = 0;
-	fs_info->pending_quota_state = 0;
-	fs_info->qgroup_ulist = NULL;
-	mutex_init(&fs_info->qgroup_rescan_lock);
+	btrfs_init_dev_replace_locks(fs_info);
+	btrfs_init_qgroup(fs_info);
 
 	btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
 	btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
@@ -2554,75 +2756,9 @@ int open_ctree(struct super_block *sb,
 
 	max_active = fs_info->thread_pool_size;
 
-	fs_info->workers =
-		btrfs_alloc_workqueue("worker", flags | WQ_HIGHPRI,
-				      max_active, 16);
-
-	fs_info->delalloc_workers =
-		btrfs_alloc_workqueue("delalloc", flags, max_active, 2);
-
-	fs_info->flush_workers =
-		btrfs_alloc_workqueue("flush_delalloc", flags, max_active, 0);
-
-	fs_info->caching_workers =
-		btrfs_alloc_workqueue("cache", flags, max_active, 0);
-
-	/*
-	 * a higher idle thresh on the submit workers makes it much more
-	 * likely that bios will be send down in a sane order to the
-	 * devices
-	 */
-	fs_info->submit_workers =
-		btrfs_alloc_workqueue("submit", flags,
-				      min_t(u64, fs_devices->num_devices,
-					    max_active), 64);
-
-	fs_info->fixup_workers =
-		btrfs_alloc_workqueue("fixup", flags, 1, 0);
-
-	/*
-	 * endios are largely parallel and should have a very
-	 * low idle thresh
-	 */
-	fs_info->endio_workers =
-		btrfs_alloc_workqueue("endio", flags, max_active, 4);
-	fs_info->endio_meta_workers =
-		btrfs_alloc_workqueue("endio-meta", flags, max_active, 4);
-	fs_info->endio_meta_write_workers =
-		btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
-	fs_info->endio_raid56_workers =
-		btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
-	fs_info->endio_repair_workers =
-		btrfs_alloc_workqueue("endio-repair", flags, 1, 0);
-	fs_info->rmw_workers =
-		btrfs_alloc_workqueue("rmw", flags, max_active, 2);
-	fs_info->endio_write_workers =
-		btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
-	fs_info->endio_freespace_worker =
-		btrfs_alloc_workqueue("freespace-write", flags, max_active, 0);
-	fs_info->delayed_workers =
-		btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
-	fs_info->readahead_workers =
-		btrfs_alloc_workqueue("readahead", flags, max_active, 2);
-	fs_info->qgroup_rescan_workers =
-		btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
-	fs_info->extent_workers =
-		btrfs_alloc_workqueue("extent-refs", flags,
-				      min_t(u64, fs_devices->num_devices,
-					    max_active), 8);
-
-	if (!(fs_info->workers && fs_info->delalloc_workers &&
-	      fs_info->submit_workers && fs_info->flush_workers &&
-	      fs_info->endio_workers && fs_info->endio_meta_workers &&
-	      fs_info->endio_meta_write_workers &&
-	      fs_info->endio_repair_workers &&
-	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
-	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
-	      fs_info->caching_workers && fs_info->readahead_workers &&
-	      fs_info->fixup_workers && fs_info->delayed_workers &&
-	      fs_info->extent_workers &&
-	      fs_info->qgroup_rescan_workers)) {
-		err = -ENOMEM;
+	ret = btrfs_init_workqueues(fs_info, fs_devices);
+	if (ret) {
+		err = ret;
 		goto fail_sb_buffer;
 	}
 
@@ -2688,7 +2824,7 @@ int open_ctree(struct super_block *sb,
 	 * keep the device that is marked to be the target device for the
 	 * dev_replace procedure
 	 */
-	btrfs_close_extra_devices(fs_info, fs_devices, 0);
+	btrfs_close_extra_devices(fs_devices, 0);
 
 	if (!fs_devices->latest_bdev) {
 		printk(KERN_ERR "BTRFS: failed to read devices on %s\n",
@@ -2714,61 +2850,9 @@ retry_root_backup:
 	tree_root->commit_root = btrfs_root_node(tree_root);
 	btrfs_set_root_refs(&tree_root->root_item, 1);
 
-	location.objectid = BTRFS_EXTENT_TREE_OBJECTID;
-	location.type = BTRFS_ROOT_ITEM_KEY;
-	location.offset = 0;
-
-	extent_root = btrfs_read_tree_root(tree_root, &location);
-	if (IS_ERR(extent_root)) {
-		ret = PTR_ERR(extent_root);
-		goto recovery_tree_root;
-	}
-	set_bit(BTRFS_ROOT_TRACK_DIRTY, &extent_root->state);
-	fs_info->extent_root = extent_root;
-
-	location.objectid = BTRFS_DEV_TREE_OBJECTID;
-	dev_root = btrfs_read_tree_root(tree_root, &location);
-	if (IS_ERR(dev_root)) {
-		ret = PTR_ERR(dev_root);
-		goto recovery_tree_root;
-	}
-	set_bit(BTRFS_ROOT_TRACK_DIRTY, &dev_root->state);
-	fs_info->dev_root = dev_root;
-	btrfs_init_devices_late(fs_info);
-
-	location.objectid = BTRFS_CSUM_TREE_OBJECTID;
-	csum_root = btrfs_read_tree_root(tree_root, &location);
-	if (IS_ERR(csum_root)) {
-		ret = PTR_ERR(csum_root);
+	ret = btrfs_read_roots(fs_info, tree_root);
+	if (ret)
 		goto recovery_tree_root;
-	}
-	set_bit(BTRFS_ROOT_TRACK_DIRTY, &csum_root->state);
-	fs_info->csum_root = csum_root;
-
-	location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
-	quota_root = btrfs_read_tree_root(tree_root, &location);
-	if (!IS_ERR(quota_root)) {
-		set_bit(BTRFS_ROOT_TRACK_DIRTY, &quota_root->state);
-		fs_info->quota_enabled = 1;
-		fs_info->pending_quota_state = 1;
-		fs_info->quota_root = quota_root;
-	}
-
-	location.objectid = BTRFS_UUID_TREE_OBJECTID;
-	uuid_root = btrfs_read_tree_root(tree_root, &location);
-	if (IS_ERR(uuid_root)) {
-		ret = PTR_ERR(uuid_root);
-		if (ret != -ENOENT)
-			goto recovery_tree_root;
-		create_uuid_tree = true;
-		check_uuid_tree = false;
-	} else {
-		set_bit(BTRFS_ROOT_TRACK_DIRTY, &uuid_root->state);
-		fs_info->uuid_root = uuid_root;
-		create_uuid_tree = false;
-		check_uuid_tree =
-		    generation != btrfs_super_uuid_tree_generation(disk_super);
-	}
 
 	fs_info->generation = generation;
 	fs_info->last_trans_committed = generation;
@@ -2792,7 +2876,7 @@ retry_root_backup:
 		goto fail_block_groups;
 	}
 
-	btrfs_close_extra_devices(fs_info, fs_devices, 1);
+	btrfs_close_extra_devices(fs_devices, 1);
 
 	ret = btrfs_sysfs_add_one(fs_info);
 	if (ret) {
@@ -2806,7 +2890,7 @@ retry_root_backup:
 		goto fail_sysfs;
 	}
 
-	ret = btrfs_read_block_groups(extent_root);
+	ret = btrfs_read_block_groups(fs_info->extent_root);
 	if (ret) {
 		printk(KERN_ERR "BTRFS: Failed to read block groups: %d\n", ret);
 		goto fail_sysfs;
@@ -2864,48 +2948,11 @@ retry_root_backup:
 
 	/* do not make disk changes in broken FS */
 	if (btrfs_super_log_root(disk_super) != 0) {
-		u64 bytenr = btrfs_super_log_root(disk_super);
-
-		if (fs_devices->rw_devices == 0) {
-			printk(KERN_WARNING "BTRFS: log replay required "
-			       "on RO media\n");
-			err = -EIO;
-			goto fail_qgroup;
-		}
-
-		log_tree_root = btrfs_alloc_root(fs_info);
-		if (!log_tree_root) {
-			err = -ENOMEM;
-			goto fail_qgroup;
-		}
-
-		__setup_root(nodesize, sectorsize, stripesize,
-			     log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
-
-		log_tree_root->node = read_tree_block(tree_root, bytenr,
-						      generation + 1);
-		if (!log_tree_root->node ||
-		    !extent_buffer_uptodate(log_tree_root->node)) {
-			printk(KERN_ERR "BTRFS: failed to read log tree\n");
-			free_extent_buffer(log_tree_root->node);
-			kfree(log_tree_root);
-			goto fail_qgroup;
-		}
-		/* returns with log_tree_root freed on success */
-		ret = btrfs_recover_log_trees(log_tree_root);
+		ret = btrfs_replay_log(fs_info, fs_devices);
 		if (ret) {
-			btrfs_error(tree_root->fs_info, ret,
-				    "Failed to recover log tree");
-			free_extent_buffer(log_tree_root->node);
-			kfree(log_tree_root);
+			err = ret;
 			goto fail_qgroup;
 		}
-
-		if (sb->s_flags & MS_RDONLY) {
-			ret = btrfs_commit_super(tree_root);
-			if (ret)
-				goto fail_qgroup;
-		}
 	}
 
 	ret = btrfs_find_orphan_roots(tree_root);
@@ -2966,7 +3013,7 @@ retry_root_backup:
 
 	btrfs_qgroup_rescan_resume(fs_info);
 
-	if (create_uuid_tree) {
+	if (!fs_info->uuid_root) {
 		pr_info("BTRFS: creating UUID tree\n");
 		ret = btrfs_create_uuid_tree(fs_info);
 		if (ret) {
@@ -2975,8 +3022,9 @@ retry_root_backup:
 			close_ctree(tree_root);
 			return ret;
 		}
-	} else if (check_uuid_tree ||
-		   btrfs_test_opt(tree_root, RESCAN_UUID_TREE)) {
+	} else if (btrfs_test_opt(tree_root, RESCAN_UUID_TREE) ||
+		   fs_info->generation !=
+				btrfs_super_uuid_tree_generation(disk_super)) {
 		pr_info("BTRFS: checking UUID tree\n");
 		ret = btrfs_check_uuid_tree(fs_info);
 		if (ret) {
@@ -3668,7 +3716,7 @@ void close_ctree(struct btrfs_root *root)
 	if (!(fs_info->sb->s_flags & MS_RDONLY)) {
 		ret = btrfs_commit_super(root);
 		if (ret)
-			btrfs_err(root->fs_info, "commit super ret %d", ret);
+			btrfs_err(fs_info, "commit super ret %d", ret);
 	}
 
 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
@@ -3680,10 +3728,10 @@ void close_ctree(struct btrfs_root *root)
 	fs_info->closing = 2;
 	smp_mb();
 
-	btrfs_free_qgroup_config(root->fs_info);
+	btrfs_free_qgroup_config(fs_info);
 
 	if (percpu_counter_sum(&fs_info->delalloc_bytes)) {
-		btrfs_info(root->fs_info, "at unmount delalloc count %lld",
+		btrfs_info(fs_info, "at unmount delalloc count %lld",
 		       percpu_counter_sum(&fs_info->delalloc_bytes));
 	}
 
@@ -4134,7 +4182,7 @@ static int btrfs_destroy_marked_extents(struct btrfs_root *root,
 
 		clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
 		while (start <= end) {
-			eb = btrfs_find_tree_block(root, start);
+			eb = btrfs_find_tree_block(root->fs_info, start);
 			start += root->nodesize;
 			if (!eb)
 				continue;
@@ -4285,7 +4333,7 @@ static int btrfs_cleanup_transaction(struct btrfs_root *root)
 	return 0;
 }
 
-static struct extent_io_ops btree_extent_io_ops = {
+static const struct extent_io_ops btree_extent_io_ops = {
 	.readpage_end_io_hook = btree_readpage_end_io_hook,
 	.readpage_io_failed_hook = btree_io_failed_hook,
 	.submit_bio_hook = btree_submit_bio_hook,
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 27d44c0..d4cbfee 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -52,7 +52,7 @@ int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr,
 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 						   u64 bytenr);
 void clean_tree_block(struct btrfs_trans_handle *trans,
-		      struct btrfs_root *root, struct extent_buffer *buf);
+		      struct btrfs_fs_info *fs_info, struct extent_buffer *buf);
 int open_ctree(struct super_block *sb,
 	       struct btrfs_fs_devices *fs_devices,
 	       char *options);
@@ -61,7 +61,7 @@ int write_ctree_super(struct btrfs_trans_handle *trans,
 		      struct btrfs_root *root, int max_mirrors);
 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev);
 int btrfs_commit_super(struct btrfs_root *root);
-struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
+struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info,
 					    u64 bytenr);
 struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
 				      struct btrfs_key *location);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index d2158c4..d8ce3cf 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3640,7 +3640,7 @@ int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	u64 used;
-	int ret = 0, committed = 0, alloc_chunk = 1;
+	int ret = 0, committed = 0;
 
 	/* make sure bytes are sectorsize aligned */
 	bytes = ALIGN(bytes, root->sectorsize);
@@ -3668,7 +3668,7 @@ again:
 		 * if we don't have enough free bytes in this space then we need
 		 * to alloc a new chunk.
 		 */
-		if (!data_sinfo->full && alloc_chunk) {
+		if (!data_sinfo->full) {
 			u64 alloc_target;
 
 			data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
@@ -7216,7 +7216,7 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 	btrfs_set_header_generation(buf, trans->transid);
 	btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
 	btrfs_tree_lock(buf);
-	clean_tree_block(trans, root, buf);
+	clean_tree_block(trans, root->fs_info, buf);
 	clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
 
 	btrfs_set_lock_blocking(buf);
@@ -7814,7 +7814,7 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
 	bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
 	blocksize = root->nodesize;
 
-	next = btrfs_find_tree_block(root, bytenr);
+	next = btrfs_find_tree_block(root->fs_info, bytenr);
 	if (!next) {
 		next = btrfs_find_create_tree_block(root, bytenr);
 		if (!next)
@@ -8015,7 +8015,7 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
 			btrfs_set_lock_blocking(eb);
 			path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
 		}
-		clean_tree_block(trans, root, eb);
+		clean_tree_block(trans, root->fs_info, eb);
 	}
 
 	if (eb == root->node) {
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 695b0cc..c668f36 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -97,7 +97,7 @@ struct extent_io_tree {
 	u64 dirty_bytes;
 	int track_uptodate;
 	spinlock_t lock;
-	struct extent_io_ops *ops;
+	const struct extent_io_ops *ops;
 };
 
 struct extent_state {
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 3a4a792..58ece65 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -553,7 +553,7 @@ static noinline void truncate_one_csum(struct btrfs_root *root,
 		btrfs_truncate_item(root, path, new_size, 0);
 
 		key->offset = end_byte;
-		btrfs_set_item_key_safe(root, path, key);
+		btrfs_set_item_key_safe(root->fs_info, path, key);
 	} else {
 		BUG();
 	}
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index ac26a91..7d4bb3b 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -864,7 +864,7 @@ next_slot:
 
 			memcpy(&new_key, &key, sizeof(new_key));
 			new_key.offset = end;
-			btrfs_set_item_key_safe(root, path, &new_key);
+			btrfs_set_item_key_safe(root->fs_info, path, &new_key);
 
 			extent_offset += end - key.offset;
 			btrfs_set_file_extent_offset(leaf, fi, extent_offset);
@@ -1122,7 +1122,7 @@ again:
 				     ino, bytenr, orig_offset,
 				     &other_start, &other_end)) {
 			new_key.offset = end;
-			btrfs_set_item_key_safe(root, path, &new_key);
+			btrfs_set_item_key_safe(root->fs_info, path, &new_key);
 			fi = btrfs_item_ptr(leaf, path->slots[0],
 					    struct btrfs_file_extent_item);
 			btrfs_set_file_extent_generation(leaf, fi,
@@ -1156,7 +1156,7 @@ again:
 							 trans->transid);
 			path->slots[0]++;
 			new_key.offset = start;
-			btrfs_set_item_key_safe(root, path, &new_key);
+			btrfs_set_item_key_safe(root->fs_info, path, &new_key);
 
 			fi = btrfs_item_ptr(leaf, path->slots[0],
 					    struct btrfs_file_extent_item);
@@ -2164,7 +2164,7 @@ static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
 		u64 num_bytes;
 
 		key.offset = offset;
-		btrfs_set_item_key_safe(root, path, &key);
+		btrfs_set_item_key_safe(root->fs_info, path, &key);
 		fi = btrfs_item_ptr(leaf, path->slots[0],
 				    struct btrfs_file_extent_item);
 		num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index 617553c..a2f0513 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -434,7 +434,7 @@ out:
 	return ret;
 }
 
-struct btrfs_compress_op btrfs_lzo_compress = {
+const struct btrfs_compress_op btrfs_lzo_compress = {
 	.alloc_workspace	= lzo_alloc_workspace,
 	.free_workspace		= lzo_free_workspace,
 	.compress_pages		= lzo_compress_pages,
diff --git a/fs/btrfs/props.c b/fs/btrfs/props.c
index 129b1dd..dca137b 100644
--- a/fs/btrfs/props.c
+++ b/fs/btrfs/props.c
@@ -425,3 +425,5 @@ static const char *prop_compression_extract(struct inode *inode)
 
 	return NULL;
 }
+
+
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index e08d26a..33f3137 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -982,7 +982,7 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
 	list_del(&quota_root->dirty_list);
 
 	btrfs_tree_lock(quota_root->node);
-	clean_tree_block(trans, tree_root, quota_root->node);
+	clean_tree_block(trans, tree_root->fs_info, quota_root->node);
 	btrfs_tree_unlock(quota_root->node);
 	btrfs_free_tree_block(trans, quota_root, quota_root->node, 0, 1);
 
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index b4634c3..fa72068 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -237,12 +237,8 @@ int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
 	}
 
 	x = cmpxchg(&info->stripe_hash_table, NULL, table);
-	if (x) {
-		if (is_vmalloc_addr(x))
-			vfree(x);
-		else
-			kfree(x);
-	}
+	if (x)
+		kvfree(x);
 	return 0;
 }
 
@@ -453,10 +449,7 @@ void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
 	if (!info->stripe_hash_table)
 		return;
 	btrfs_clear_rbio_cache(info);
-	if (is_vmalloc_addr(info->stripe_hash_table))
-		vfree(info->stripe_hash_table);
-	else
-		kfree(info->stripe_hash_table);
+	kvfree(info->stripe_hash_table);
 	info->stripe_hash_table = NULL;
 }
 
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 34e6499..ab58115 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3560,7 +3560,7 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
 						int is_dev_replace)
 {
 	int ret = 0;
-	int flags = WQ_FREEZABLE | WQ_UNBOUND;
+	unsigned int flags = WQ_FREEZABLE | WQ_UNBOUND;
 	int max_active = fs_info->thread_pool_size;
 
 	if (fs_info->scrub_workers_refcnt == 0) {
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 94edb0a..e8a4c86 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -459,7 +459,7 @@ static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
 static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
 static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
 
-static u64 supported_feature_masks[3] = {
+static const u64 supported_feature_masks[3] = {
 	[FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
 	[FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
 	[FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index fae816b..91c303a 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -35,7 +35,7 @@
 
 #define BTRFS_ROOT_TRANS_TAG 0
 
-static unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
+static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
 	[TRANS_STATE_RUNNING]		= 0U,
 	[TRANS_STATE_BLOCKED]		= (__TRANS_USERSPACE |
 					   __TRANS_START),
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index c5b8ba3..066e754 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2230,7 +2230,8 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
 				if (trans) {
 					btrfs_tree_lock(next);
 					btrfs_set_lock_blocking(next);
-					clean_tree_block(trans, root, next);
+					clean_tree_block(trans, root->fs_info,
+							next);
 					btrfs_wait_tree_block_writeback(next);
 					btrfs_tree_unlock(next);
 				}
@@ -2308,7 +2309,8 @@ static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
 				if (trans) {
 					btrfs_tree_lock(next);
 					btrfs_set_lock_blocking(next);
-					clean_tree_block(trans, root, next);
+					clean_tree_block(trans, root->fs_info,
+							next);
 					btrfs_wait_tree_block_writeback(next);
 					btrfs_tree_unlock(next);
 				}
@@ -2384,7 +2386,7 @@ static int walk_log_tree(struct btrfs_trans_handle *trans,
 			if (trans) {
 				btrfs_tree_lock(next);
 				btrfs_set_lock_blocking(next);
-				clean_tree_block(trans, log, next);
+				clean_tree_block(trans, log->fs_info, next);
 				btrfs_wait_tree_block_writeback(next);
 				btrfs_tree_unlock(next);
 			}
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 64ec2fd..a73acf4 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -608,8 +608,7 @@ error:
 	return ERR_PTR(-ENOMEM);
 }
 
-void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
-			       struct btrfs_fs_devices *fs_devices, int step)
+void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step)
 {
 	struct btrfs_device *device, *next;
 	struct btrfs_device *latest_dev = NULL;
@@ -2486,8 +2485,7 @@ int btrfs_grow_device(struct btrfs_trans_handle *trans,
 }
 
 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
-			    struct btrfs_root *root,
-			    u64 chunk_tree, u64 chunk_objectid,
+			    struct btrfs_root *root, u64 chunk_objectid,
 			    u64 chunk_offset)
 {
 	int ret;
@@ -2579,7 +2577,6 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
 	struct map_lookup *map;
 	u64 dev_extent_len = 0;
 	u64 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
-	u64 chunk_tree = root->fs_info->chunk_root->objectid;
 	int i, ret = 0;
 
 	/* Just in case */
@@ -2633,8 +2630,7 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
 			}
 		}
 	}
-	ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
-			       chunk_offset);
+	ret = btrfs_free_chunk(trans, root, chunk_objectid, chunk_offset);
 	if (ret) {
 		btrfs_abort_transaction(trans, root, ret);
 		goto out;
@@ -2663,8 +2659,8 @@ out:
 }
 
 static int btrfs_relocate_chunk(struct btrfs_root *root,
-			 u64 chunk_tree, u64 chunk_objectid,
-			 u64 chunk_offset)
+				u64 chunk_objectid,
+				u64 chunk_offset)
 {
 	struct btrfs_root *extent_root;
 	struct btrfs_trans_handle *trans;
@@ -2706,7 +2702,6 @@ static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
 	struct btrfs_chunk *chunk;
 	struct btrfs_key key;
 	struct btrfs_key found_key;
-	u64 chunk_tree = chunk_root->root_key.objectid;
 	u64 chunk_type;
 	bool retried = false;
 	int failed = 0;
@@ -2743,7 +2738,7 @@ again:
 		btrfs_release_path(path);
 
 		if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
-			ret = btrfs_relocate_chunk(chunk_root, chunk_tree,
+			ret = btrfs_relocate_chunk(chunk_root,
 						   found_key.objectid,
 						   found_key.offset);
 			if (ret == -ENOSPC)
@@ -3254,7 +3249,6 @@ again:
 		}
 
 		ret = btrfs_relocate_chunk(chunk_root,
-					   chunk_root->root_key.objectid,
 					   found_key.objectid,
 					   found_key.offset);
 		if (ret && ret != -ENOSPC)
@@ -3956,7 +3950,6 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 	struct btrfs_dev_extent *dev_extent = NULL;
 	struct btrfs_path *path;
 	u64 length;
-	u64 chunk_tree;
 	u64 chunk_objectid;
 	u64 chunk_offset;
 	int ret;
@@ -4026,13 +4019,11 @@ again:
 			break;
 		}
 
-		chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
 		chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
 		chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
 		btrfs_release_path(path);
 
-		ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
-					   chunk_offset);
+		ret = btrfs_relocate_chunk(root, chunk_objectid, chunk_offset);
 		if (ret && ret != -ENOSPC)
 			goto done;
 		if (ret == -ENOSPC)
@@ -4130,7 +4121,7 @@ static int btrfs_cmp_device_info(const void *a, const void *b)
 	return 0;
 }
 
-static struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
+static const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 	[BTRFS_RAID_RAID10] = {
 		.sub_stripes	= 2,
 		.dev_stripes	= 1,
@@ -5833,8 +5824,8 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 	u64 length = 0;
 	u64 map_length;
 	int ret;
-	int dev_nr = 0;
-	int total_devs = 1;
+	int dev_nr;
+	int total_devs;
 	struct btrfs_bio *bbio = NULL;
 
 	length = bio->bi_iter.bi_size;
@@ -5875,11 +5866,10 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 		BUG();
 	}
 
-	while (dev_nr < total_devs) {
+	for (dev_nr = 0; dev_nr < total_devs; dev_nr++) {
 		dev = bbio->stripes[dev_nr].dev;
 		if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
 			bbio_error(bbio, first_bio, logical);
-			dev_nr++;
 			continue;
 		}
 
@@ -5892,7 +5882,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 			ret = breakup_stripe_bio(root, bbio, first_bio, dev,
 						 dev_nr, rw, async_submit);
 			BUG_ON(ret);
-			dev_nr++;
 			continue;
 		}
 
@@ -5907,7 +5896,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 		submit_stripe_bio(root, bbio, bio,
 				  bbio->stripes[dev_nr].physical, dev_nr, rw,
 				  async_submit);
-		dev_nr++;
 	}
 	btrfs_bio_counter_dec(root->fs_info);
 	return 0;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 83069de..ebc3133 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -421,8 +421,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 			  struct btrfs_fs_devices **fs_devices_ret);
 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
-void btrfs_close_extra_devices(struct btrfs_fs_info *fs_info,
-			       struct btrfs_fs_devices *fs_devices, int step);
+void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step);
 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
 					 char *device_path,
 					 struct btrfs_device **device);
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index fb22fd8..82990b8 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -403,7 +403,7 @@ next:
 	return ret;
 }
 
-struct btrfs_compress_op btrfs_zlib_compress = {
+const struct btrfs_compress_op btrfs_zlib_compress = {
 	.alloc_workspace	= zlib_alloc_workspace,
 	.free_workspace		= zlib_free_workspace,
 	.compress_pages		= zlib_compress_pages,