From cd354ad613a393424f85333ceed6b15e07fb94ae Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Thu, 20 Oct 2011 15:45:37 -0400
Subject: Btrfs: don't wait as long for more batches during SSD log commit

When we're doing log commits, we try to wait for more writers to come in
and make the commit bigger.  This helps improve performance on rotating
disks, but on SSDs it adds latencies.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
---
 fs/btrfs/tree-log.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'fs/btrfs/tree-log.c')

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 786639fca067..310ab22cfe58 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2013,10 +2013,10 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
 	/* wait for previous tree log sync to complete */
 	if (atomic_read(&root->log_commit[(index1 + 1) % 2]))
 		wait_log_commit(trans, root, root->log_transid - 1);
-
 	while (1) {
 		unsigned long batch = root->log_batch;
-		if (root->log_multiple_pids) {
+		/* when we're on an ssd, just kick the log commit out */
+		if (!btrfs_test_opt(root, SSD) && root->log_multiple_pids) {
 			mutex_unlock(&root->log_mutex);
 			schedule_timeout_uninterruptible(1);
 			mutex_lock(&root->log_mutex);
-- 
cgit v1.2.3


From e688b7252f784c2479d559f9f70ca8354752c5e7 Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Mon, 31 Oct 2011 20:52:39 -0400
Subject: Btrfs: fix extent pinning bugs in the tree log

The tree log had two important bugs that could cause corruptions after a
crash.  Sometimes we were allowing tree log blocks to be reused after
the tree log was committed but before the transaction commit was done.

This allowed a future metadata write to overwrite the tree log data.  It
is fixed by adding a new variant of freeing reserved extents that always
pins them.  Credit goes to Stefan Behrens and Arne Jansen for many many
hours spent tracking this bug down.

During tree log replay, we do a pass through the tree log and pin all
the extents we find.  This makes sure the replay code won't go in and
use any of those blocks for new allocations during replay.  The problem
is the free space cache isn't honoring these pinned extents.  So the
allocator can end up handing them out, leading to all kinds of problems
during replay.

The fix here is to force any free space cache to load while we pin the
extents, and then to make sure we remove the pinned extents from the
free space rbtree.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Reported-by: Stefan Behrens <sbehrens@giantdisaster.de>
---
 fs/btrfs/ctree.h       |  5 +++++
 fs/btrfs/extent-tree.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++---
 fs/btrfs/tree-log.c    | 11 ++++++-----
 3 files changed, 59 insertions(+), 8 deletions(-)

(limited to 'fs/btrfs/tree-log.c')

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 227620993bce..f63c9b3f6e08 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2156,6 +2156,9 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 			     u64 num_bytes, u64 *refs, u64 *flags);
 int btrfs_pin_extent(struct btrfs_root *root,
 		     u64 bytenr, u64 num, int reserved);
+int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
+				    struct btrfs_root *root,
+				    u64 bytenr, u64 num_bytes);
 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root,
 			  u64 objectid, u64 offset, u64 bytenr);
@@ -2206,6 +2209,8 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans,
 		      u64 root_objectid, u64 owner, u64 offset);
 
 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len);
+int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
+				       u64 start, u64 len);
 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
 				struct btrfs_root *root);
 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 28c4809851a5..cb7626646bba 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4344,6 +4344,34 @@ int btrfs_pin_extent(struct btrfs_root *root,
 	return 0;
 }
 
+/*
+ * this function must be called within transaction
+ */
+int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
+				    struct btrfs_root *root,
+				    u64 bytenr, u64 num_bytes)
+{
+	struct btrfs_block_group_cache *cache;
+
+	cache = btrfs_lookup_block_group(root->fs_info, bytenr);
+	BUG_ON(!cache);
+
+	/*
+	 * pull in the free space cache (if any) so that our pin
+	 * removes the free space from the cache.  We have load_only set
+	 * to one because the slow code to read in the free extents does check
+	 * the pinned extents.
+	 */
+	cache_block_group(cache, trans, root, 1);
+
+	pin_down_extent(root, cache, bytenr, num_bytes, 0);
+
+	/* remove us from the free space cache (if we're there at all) */
+	btrfs_remove_free_space(cache, bytenr, num_bytes);
+	btrfs_put_block_group(cache);
+	return 0;
+}
+
 /**
  * btrfs_update_reserved_bytes - update the block_group and space info counters
  * @cache:	The cache we are manipulating
@@ -5487,7 +5515,8 @@ again:
 	return ret;
 }
 
-int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
+static int __btrfs_free_reserved_extent(struct btrfs_root *root,
+					u64 start, u64 len, int pin)
 {
 	struct btrfs_block_group_cache *cache;
 	int ret = 0;
@@ -5502,8 +5531,12 @@ int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
 	if (btrfs_test_opt(root, DISCARD))
 		ret = btrfs_discard_extent(root, start, len, NULL);
 
-	btrfs_add_free_space(cache, start, len);
-	btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
+	if (pin)
+		pin_down_extent(root, cache, start, len, 1);
+	else {
+		btrfs_add_free_space(cache, start, len);
+		btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
+	}
 	btrfs_put_block_group(cache);
 
 	trace_btrfs_reserved_extent_free(root, start, len);
@@ -5511,6 +5544,18 @@ int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
 	return ret;
 }
 
+int btrfs_free_reserved_extent(struct btrfs_root *root,
+					u64 start, u64 len)
+{
+	return __btrfs_free_reserved_extent(root, start, len, 0);
+}
+
+int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
+				       u64 start, u64 len)
+{
+	return __btrfs_free_reserved_extent(root, start, len, 1);
+}
+
 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
 				      struct btrfs_root *root,
 				      u64 parent, u64 root_objectid,
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 310ab22cfe58..8ca1b6b83bd1 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -276,8 +276,9 @@ static int process_one_buffer(struct btrfs_root *log,
 			      struct walk_control *wc, u64 gen)
 {
 	if (wc->pin)
-		btrfs_pin_extent(log->fs_info->extent_root,
-				 eb->start, eb->len, 0);
+		btrfs_pin_extent_for_log_replay(wc->trans,
+						log->fs_info->extent_root,
+						eb->start, eb->len);
 
 	if (btrfs_buffer_uptodate(eb, gen)) {
 		if (wc->write)
@@ -1760,7 +1761,7 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
 
 				WARN_ON(root_owner !=
 					BTRFS_TREE_LOG_OBJECTID);
-				ret = btrfs_free_reserved_extent(root,
+				ret = btrfs_free_and_pin_reserved_extent(root,
 							 bytenr, blocksize);
 				BUG_ON(ret);
 			}
@@ -1828,7 +1829,7 @@ static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
 				btrfs_tree_unlock(next);
 
 				WARN_ON(root_owner != BTRFS_TREE_LOG_OBJECTID);
-				ret = btrfs_free_reserved_extent(root,
+				ret = btrfs_free_and_pin_reserved_extent(root,
 						path->nodes[*level]->start,
 						path->nodes[*level]->len);
 				BUG_ON(ret);
@@ -1897,7 +1898,7 @@ static int walk_log_tree(struct btrfs_trans_handle *trans,
 
 			WARN_ON(log->root_key.objectid !=
 				BTRFS_TREE_LOG_OBJECTID);
-			ret = btrfs_free_reserved_extent(log, next->start,
+			ret = btrfs_free_and_pin_reserved_extent(log, next->start,
 							 next->len);
 			BUG_ON(ret);
 		}
-- 
cgit v1.2.3


From 6c41761fc6efe1503103a1afe03a6635c0b5d4ec Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.cz>
Date: Wed, 13 Apr 2011 15:41:04 +0200
Subject: 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>
---
 fs/btrfs/compression.c |  3 ++-
 fs/btrfs/ctree.h       | 16 ++++++++++++++--
 fs/btrfs/disk-io.c     | 33 ++++++++++-----------------------
 fs/btrfs/extent-tree.c | 16 ++++++++--------
 fs/btrfs/file-item.c   | 17 ++++++-----------
 fs/btrfs/inode.c       |  2 +-
 fs/btrfs/ioctl.c       |  8 ++++----
 fs/btrfs/scrub.c       |  2 +-
 fs/btrfs/super.c       | 19 +++++++++++++------
 fs/btrfs/transaction.c | 10 +++++-----
 fs/btrfs/tree-log.c    |  4 ++--
 fs/btrfs/volumes.c     | 24 ++++++++++++------------
 12 files changed, 78 insertions(+), 76 deletions(-)

(limited to 'fs/btrfs/tree-log.c')

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;
-- 
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