btrfs: separate superblock items out of fs_info

fs_info has now ~9kb, more than fits into one page. This will cause
mount failure when memory is too fragmented. Top space consumers are
super block structures super_copy and super_for_commit, ~2.8kb each.
Allocate them dynamically. fs_info will be ~3.5kb. (measured on x86_64)

Add a wrapper for freeing fs_info and all of it's dynamically allocated
members.

Signed-off-by: David Sterba <dsterba@suse.cz>

12 files changed, 78 insertions, 76 deletions

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 8ec5d86f1734..14f1c5a0b2d2 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -85,7 +85,8 @@ struct compressed_bio {
 static inline int compressed_bio_size(struct btrfs_root *root,
                                       unsigned long disk_size)
 {
-        u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy);
+        u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
+
         return sizeof(struct compressed_bio) +
                 ((disk_size + root->sectorsize - 1) / root->sectorsize) *
                 csum_size;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f63c9b3f6e08..5181c53c1124 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -936,8 +936,8 @@ struct btrfs_fs_info {
         wait_queue_head_t transaction_blocked_wait;
         wait_queue_head_t async_submit_wait;
 
-        struct btrfs_super_block super_copy;
-        struct btrfs_super_block super_for_commit;
+        struct btrfs_super_block *super_copy;
+        struct btrfs_super_block *super_for_commit;
         struct block_device *__bdev;
         struct super_block *sb;
         struct inode *btree_inode;
@@ -2387,6 +2387,18 @@ static inline int btrfs_fs_closing(struct btrfs_fs_info *fs_info)
         smp_mb();
         return fs_info->closing;
 }
+static inline void free_fs_info(struct btrfs_fs_info *fs_info)
+{
+        kfree(fs_info->delayed_root);
+        kfree(fs_info->extent_root);
+        kfree(fs_info->tree_root);
+        kfree(fs_info->chunk_root);
+        kfree(fs_info->dev_root);
+        kfree(fs_info->csum_root);
+        kfree(fs_info->super_copy);
+        kfree(fs_info->super_for_commit);
+        kfree(fs_info);
+}
 
 /* root-item.c */
 int btrfs_find_root_ref(struct btrfs_root *tree_root,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 6f58911ece0d..761717c98278 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -256,8 +256,7 @@ void btrfs_csum_final(u32 crc, char *result)
 static int csum_tree_block(struct btrfs_root *root, 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(root->fs_info->super_copy);
         char *result = NULL;
         unsigned long len;
         unsigned long cur_len;
@@ -1766,14 +1765,14 @@ struct btrfs_root *open_ctree(struct super_block *sb,
                 goto fail_alloc;
         }
 
-        memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
-        memcpy(&fs_info->super_for_commit, &fs_info->super_copy,
-               sizeof(fs_info->super_for_commit));
+        memcpy(fs_info->super_copy, bh->b_data, sizeof(*fs_info->super_copy));
+        memcpy(fs_info->super_for_commit, fs_info->super_copy,
+               sizeof(*fs_info->super_for_commit));
         brelse(bh);
 
-        memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
+        memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
 
-        disk_super = &fs_info->super_copy;
+        disk_super = fs_info->super_copy;
         if (!btrfs_super_root(disk_super))
                 goto fail_alloc;
 
@@ -2152,7 +2151,6 @@ fail_sb_buffer:
         btrfs_stop_workers(&fs_info->delayed_workers);
         btrfs_stop_workers(&fs_info->caching_workers);
 fail_alloc:
-        kfree(fs_info->delayed_root);
 fail_iput:
         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
         iput(fs_info->btree_inode);
@@ -2164,12 +2162,7 @@ fail_bdi:
 fail_srcu:
         cleanup_srcu_struct(&fs_info->subvol_srcu);
 fail:
-        kfree(extent_root);
-        kfree(tree_root);
-        kfree(fs_info);
-        kfree(chunk_root);
-        kfree(dev_root);
-        kfree(csum_root);
+        free_fs_info(fs_info);
         return ERR_PTR(err);
 }
 
@@ -2338,10 +2331,10 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors)
         int total_errors = 0;
         u64 flags;
 
-        max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
+        max_errors = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
         do_barriers = !btrfs_test_opt(root, NOBARRIER);
 
-        sb = &root->fs_info->super_for_commit;
+        sb = root->fs_info->super_for_commit;
         dev_item = &sb->dev_item;
 
         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
@@ -2603,7 +2596,6 @@ int close_ctree(struct btrfs_root *root)
         del_fs_roots(fs_info);
 
         iput(fs_info->btree_inode);
-        kfree(fs_info->delayed_root);
 
         btrfs_stop_workers(&fs_info->generic_worker);
         btrfs_stop_workers(&fs_info->fixup_workers);
@@ -2624,12 +2616,7 @@ int close_ctree(struct btrfs_root *root)
         bdi_destroy(&fs_info->bdi);
         cleanup_srcu_struct(&fs_info->subvol_srcu);
 
-        kfree(fs_info->extent_root);
-        kfree(fs_info->tree_root);
-        kfree(fs_info->chunk_root);
-        kfree(fs_info->dev_root);
-        kfree(fs_info->csum_root);
-        kfree(fs_info);
+        free_fs_info(fs_info);
 
         return 0;
 }
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index cb7626646bba..782eb3ea8edf 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3209,7 +3209,7 @@ static int should_alloc_chunk(struct btrfs_root *root,
          * about 1% of the FS size.
          */
         if (force == CHUNK_ALLOC_LIMITED) {
-                thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
+                thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
                 thresh = max_t(u64, 64 * 1024 * 1024,
                                div_factor_fine(thresh, 1));
 
@@ -3231,7 +3231,7 @@ static int should_alloc_chunk(struct btrfs_root *root,
         if (num_allocated + alloc_bytes < div_factor(num_bytes, 8))
                 return 0;
 
-        thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
+        thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
 
         /* 256MB or 5% of the FS */
         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));
@@ -3843,7 +3843,7 @@ static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
         u64 num_bytes;
         u64 meta_used;
         u64 data_used;
-        int csum_size = btrfs_super_csum_size(&fs_info->super_copy);
+        int csum_size = btrfs_super_csum_size(fs_info->super_copy);
 
         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
         spin_lock(&sinfo->lock);
@@ -4222,12 +4222,12 @@ static int update_block_group(struct btrfs_trans_handle *trans,
 
         /* block accounting for super block */
         spin_lock(&info->delalloc_lock);
-        old_val = btrfs_super_bytes_used(&info->super_copy);
+        old_val = btrfs_super_bytes_used(info->super_copy);
         if (alloc)
                 old_val += num_bytes;
         else
                 old_val -= num_bytes;
-        btrfs_set_super_bytes_used(&info->super_copy, old_val);
+        btrfs_set_super_bytes_used(info->super_copy, old_val);
         spin_unlock(&info->delalloc_lock);
 
         while (total) {
@@ -7127,9 +7127,9 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                 return -ENOMEM;
         path->reada = 1;
 
-        cache_gen = btrfs_super_cache_generation(&root->fs_info->super_copy);
+        cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
         if (btrfs_test_opt(root, SPACE_CACHE) &&
-            btrfs_super_generation(&root->fs_info->super_copy) != cache_gen)
+            btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
                 need_clear = 1;
         if (btrfs_test_opt(root, CLEAR_CACHE))
                 need_clear = 1;
@@ -7458,7 +7458,7 @@ int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
         int mixed = 0;
         int ret;
 
-        disk_super = &fs_info->super_copy;
+        disk_super = fs_info->super_copy;
         if (!btrfs_super_root(disk_super))
                 return 1;
 
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index a1cb7821becd..c7fb3a4247d3 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -91,8 +91,7 @@ struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
         struct btrfs_csum_item *item;
         struct extent_buffer *leaf;
         u64 csum_offset = 0;
-        u16 csum_size =
-                btrfs_super_csum_size(&root->fs_info->super_copy);
+        u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
         int csums_in_item;
 
         file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
@@ -162,8 +161,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
         u64 item_last_offset = 0;
         u64 disk_bytenr;
         u32 diff;
-        u16 csum_size =
-                btrfs_super_csum_size(&root->fs_info->super_copy);
+        u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
         int ret;
         struct btrfs_path *path;
         struct btrfs_csum_item *item = NULL;
@@ -290,7 +288,7 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
         int ret;
         size_t size;
         u64 csum_end;
-        u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy);
+        u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
 
         path = btrfs_alloc_path();
         if (!path)
@@ -492,8 +490,7 @@ static noinline int truncate_one_csum(struct btrfs_trans_handle *trans,
                                       u64 bytenr, u64 len)
 {
         struct extent_buffer *leaf;
-        u16 csum_size =
-                btrfs_super_csum_size(&root->fs_info->super_copy);
+        u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
         u64 csum_end;
         u64 end_byte = bytenr + len;
         u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits;
@@ -549,8 +546,7 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
         u64 csum_end;
         struct extent_buffer *leaf;
         int ret;
-        u16 csum_size =
-                btrfs_super_csum_size(&root->fs_info->super_copy);
+        u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
         int blocksize_bits = root->fs_info->sb->s_blocksize_bits;
 
         root = root->fs_info->csum_root;
@@ -676,8 +672,7 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
         struct btrfs_sector_sum *sector_sum;
         u32 nritems;
         u32 ins_size;
-        u16 csum_size =
-                btrfs_super_csum_size(&root->fs_info->super_copy);
+        u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
 
         path = btrfs_alloc_path();
         if (!path)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a8586e10953c..b6b612e14ed7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -824,7 +824,7 @@ static noinline int cow_file_range(struct inode *inode,
         }
 
         BUG_ON(disk_num_bytes >
-               btrfs_super_total_bytes(&root->fs_info->super_copy));
+               btrfs_super_total_bytes(root->fs_info->super_copy));
 
         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 33aae13cc74b..8f6e14279409 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -282,7 +282,7 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
         struct fstrim_range range;
         u64 minlen = ULLONG_MAX;
         u64 num_devices = 0;
-        u64 total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
+        u64 total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
         int ret;
 
         if (!capable(CAP_SYS_ADMIN))
@@ -1164,7 +1164,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
                 mutex_unlock(&inode->i_mutex);
         }
 
-        disk_super = &root->fs_info->super_copy;
+        disk_super = root->fs_info->super_copy;
         features = btrfs_super_incompat_flags(disk_super);
         if (range->compress_type == BTRFS_COMPRESS_LZO) {
                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
@@ -2613,7 +2613,7 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
                 return PTR_ERR(trans);
         }
 
-        dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
+        dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
         di = btrfs_lookup_dir_item(trans, root->fs_info->tree_root, path,
                                    dir_id, "default", 7, 1);
         if (IS_ERR_OR_NULL(di)) {
@@ -2629,7 +2629,7 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
         btrfs_mark_buffer_dirty(path->nodes[0]);
         btrfs_free_path(path);
 
-        disk_super = &root->fs_info->super_copy;
+        disk_super = root->fs_info->super_copy;
         features = btrfs_super_incompat_flags(disk_super);
         if (!(features & BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL)) {
                 features |= BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL;
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index a8d03d5efb5d..69a600f07763 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -182,7 +182,7 @@ struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
         sdev->curr = -1;
         atomic_set(&sdev->in_flight, 0);
         atomic_set(&sdev->cancel_req, 0);
-        sdev->csum_size = btrfs_super_csum_size(&fs_info->super_copy);
+        sdev->csum_size = btrfs_super_csum_size(fs_info->super_copy);
         INIT_LIST_HEAD(&sdev->csum_list);
 
         spin_lock_init(&sdev->list_lock);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 5429b1fa0bfc..f7e9de724ef2 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -216,7 +216,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
         char *compress_type;
         bool compress_force = false;
 
-        cache_gen = btrfs_super_cache_generation(&root->fs_info->super_copy);
+        cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
         if (cache_gen)
                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
 
@@ -524,7 +524,7 @@ static struct dentry *get_default_root(struct super_block *sb,
          * will mount by default if we haven't been given a specific subvolume
          * to mount.
          */
-        dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
+        dir_id = btrfs_super_root_dir(root->fs_info->super_copy);
         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
         if (IS_ERR(di)) {
                 btrfs_free_path(path);
@@ -937,6 +937,13 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
         fs_info->fs_devices = fs_devices;
         tree_root->fs_info = fs_info;
 
+        fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
+        fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
+        if (!fs_info->super_copy || !fs_info->super_for_commit) {
+                error = -ENOMEM;
+                goto error_close_devices;
+        }
+
         bdev = fs_devices->latest_bdev;
         s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
         if (IS_ERR(s)) {
@@ -951,7 +958,7 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
                 }
 
                 btrfs_close_devices(fs_devices);
-                kfree(fs_info);
+                free_fs_info(fs_info);
                 kfree(tree_root);
         } else {
                 char b[BDEVNAME_SIZE];
@@ -979,7 +986,7 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
 
 error_close_devices:
         btrfs_close_devices(fs_devices);
-        kfree(fs_info);
+        free_fs_info(fs_info);
         kfree(tree_root);
         return ERR_PTR(error);
 }
@@ -1005,7 +1012,7 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
                 if (root->fs_info->fs_devices->rw_devices == 0)
                         return -EACCES;
 
-                if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
+                if (btrfs_super_log_root(root->fs_info->super_copy) != 0)
                         return -EINVAL;
 
                 ret = btrfs_cleanup_fs_roots(root->fs_info);
@@ -1171,7 +1178,7 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
-        struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
+        struct btrfs_super_block *disk_super = root->fs_info->super_copy;
         struct list_head *head = &root->fs_info->space_info;
         struct btrfs_space_info *found;
         u64 total_used = 0;
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 29bef63e23ba..373c7ec1a026 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -991,7 +991,7 @@ static void update_super_roots(struct btrfs_root *root)
         struct btrfs_root_item *root_item;
         struct btrfs_super_block *super;
 
-        super = &root->fs_info->super_copy;
+        super = root->fs_info->super_copy;
 
         root_item = &root->fs_info->chunk_root->root_item;
         super->chunk_root = root_item->bytenr;
@@ -1301,12 +1301,12 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
         update_super_roots(root);
 
         if (!root->fs_info->log_root_recovering) {
-                btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
-                btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
+                btrfs_set_super_log_root(root->fs_info->super_copy, 0);
+                btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
         }
 
-        memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
-               sizeof(root->fs_info->super_copy));
+        memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
+               sizeof(*root->fs_info->super_copy));
 
         trans->transaction->blocked = 0;
         spin_lock(&root->fs_info->trans_lock);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 8ca1b6b83bd1..f4d81c06d48f 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2118,9 +2118,9 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
         BUG_ON(ret);
         btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark);
 
-        btrfs_set_super_log_root(&root->fs_info->super_for_commit,
+        btrfs_set_super_log_root(root->fs_info->super_for_commit,
                                 log_root_tree->node->start);
-        btrfs_set_super_log_root_level(&root->fs_info->super_for_commit,
+        btrfs_set_super_log_root_level(root->fs_info->super_for_commit,
                                 btrfs_header_level(log_root_tree->node));
 
         log_root_tree->log_batch = 0;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index c6938b45e0fd..c3b45564048e 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1395,8 +1395,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
         call_rcu(&device->rcu, free_device);
         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
-        num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
-        btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
+        num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
+        btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
 
         if (cur_devices->open_devices == 0) {
                 struct btrfs_fs_devices *fs_devices;
@@ -1458,7 +1458,7 @@ static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
         struct btrfs_fs_devices *old_devices;
         struct btrfs_fs_devices *seed_devices;
-        struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
+        struct btrfs_super_block *disk_super = root->fs_info->super_copy;
         struct btrfs_device *device;
         u64 super_flags;
 
@@ -1706,12 +1706,12 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
                 root->fs_info->fs_devices->rotating = 1;
 
-        total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
-        btrfs_set_super_total_bytes(&root->fs_info->super_copy,
+        total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
+        btrfs_set_super_total_bytes(root->fs_info->super_copy,
                                     total_bytes + device->total_bytes);
 
-        total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
-        btrfs_set_super_num_devices(&root->fs_info->super_copy,
+        total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
+        btrfs_set_super_num_devices(root->fs_info->super_copy,
                                     total_bytes + 1);
         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
@@ -1802,7 +1802,7 @@ static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
                       struct btrfs_device *device, u64 new_size)
 {
         struct btrfs_super_block *super_copy =
-                &device->dev_root->fs_info->super_copy;
+                device->dev_root->fs_info->super_copy;
         u64 old_total = btrfs_super_total_bytes(super_copy);
         u64 diff = new_size - device->total_bytes;
 
@@ -1861,7 +1861,7 @@ static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
                         chunk_offset)
 {
-        struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+        struct btrfs_super_block *super_copy = root->fs_info->super_copy;
         struct btrfs_disk_key *disk_key;
         struct btrfs_chunk *chunk;
         u8 *ptr;
@@ -2187,7 +2187,7 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
         bool retried = false;
         struct extent_buffer *l;
         struct btrfs_key key;
-        struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+        struct btrfs_super_block *super_copy = root->fs_info->super_copy;
         u64 old_total = btrfs_super_total_bytes(super_copy);
         u64 old_size = device->total_bytes;
         u64 diff = device->total_bytes - new_size;
@@ -2311,7 +2311,7 @@ static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
                            struct btrfs_key *key,
                            struct btrfs_chunk *chunk, int item_size)
 {
-        struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+        struct btrfs_super_block *super_copy = root->fs_info->super_copy;
         struct btrfs_disk_key disk_key;
         u32 array_size;
         u8 *ptr;
@@ -3653,7 +3653,7 @@ static int read_one_dev(struct btrfs_root *root,
 
 int btrfs_read_sys_array(struct btrfs_root *root)
 {
-        struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+        struct btrfs_super_block *super_copy = root->fs_info->super_copy;
         struct extent_buffer *sb;
         struct btrfs_disk_key *disk_key;
         struct btrfs_chunk *chunk;