btrfs: constify more pointer parameters

Continue adding const to parameters.  This is for clarity and minor
addition to safety. There are some minor effects, in the assembly code
and .ko measured on release config.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/backref.c

@@ -219,8 +219,8 @@ static void free_pref(struct prelim_ref *ref)
  * A -1 return indicates ref1 is a 'lower' block than ref2, while 1
  * indicates a 'higher' block.
  */
-static int prelim_ref_compare(struct prelim_ref *ref1,
-			      struct prelim_ref *ref2)
+static int prelim_ref_compare(const struct prelim_ref *ref1,
+			      const struct prelim_ref *ref2)
 {
 	if (ref1->level < ref2->level)
 		return -1;
@@ -251,7 +251,7 @@ static int prelim_ref_compare(struct prelim_ref *ref1,
 }
 
 static void update_share_count(struct share_check *sc, int oldcount,
-			       int newcount, struct prelim_ref *newref)
+			       int newcount, const struct prelim_ref *newref)
 {
 	if ((!sc) || (oldcount == 0 && newcount < 1))
 		return;

fs/btrfs/block-group.c

@@ -23,7 +23,7 @@
 #include "extent-tree.h"
 
 #ifdef CONFIG_BTRFS_DEBUG
-int btrfs_should_fragment_free_space(struct btrfs_block_group *block_group)
+int btrfs_should_fragment_free_space(const struct btrfs_block_group *block_group)
 {
 	struct btrfs_fs_info *fs_info = block_group->fs_info;
 
@@ -40,9 +40,9 @@ int btrfs_should_fragment_free_space(struct btrfs_block_group *block_group)
  *
  * Should be called with balance_lock held
  */
-static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
+static u64 get_restripe_target(const struct btrfs_fs_info *fs_info, u64 flags)
 {
-	struct btrfs_balance_control *bctl = fs_info->balance_ctl;
+	const struct btrfs_balance_control *bctl = fs_info->balance_ctl;
 	u64 target = 0;
 
 	if (!bctl)
@@ -1415,9 +1415,9 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
 }
 
 static bool clean_pinned_extents(struct btrfs_trans_handle *trans,
-				 struct btrfs_block_group *bg)
+				 const struct btrfs_block_group *bg)
 {
-	struct btrfs_fs_info *fs_info = bg->fs_info;
+	struct btrfs_fs_info *fs_info = trans->fs_info;
 	struct btrfs_transaction *prev_trans = NULL;
 	const u64 start = bg->start;
 	const u64 end = start + bg->length - 1;
@@ -1756,14 +1756,14 @@ static int reclaim_bgs_cmp(void *unused, const struct list_head *a,
 	return bg1->used > bg2->used;
 }
 
-static inline bool btrfs_should_reclaim(struct btrfs_fs_info *fs_info)
+static inline bool btrfs_should_reclaim(const struct btrfs_fs_info *fs_info)
 {
 	if (btrfs_is_zoned(fs_info))
 		return btrfs_zoned_should_reclaim(fs_info);
 	return true;
 }
 
-static bool should_reclaim_block_group(struct btrfs_block_group *bg, u64 bytes_freed)
+static bool should_reclaim_block_group(const struct btrfs_block_group *bg, u64 bytes_freed)
 {
 	const int thresh_pct = btrfs_calc_reclaim_threshold(bg->space_info);
 	u64 thresh_bytes = mult_perc(bg->length, thresh_pct);
@@ -2006,8 +2006,8 @@ void btrfs_mark_bg_to_reclaim(struct btrfs_block_group *bg)
 	spin_unlock(&fs_info->unused_bgs_lock);
 }
 
-static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
-			   struct btrfs_path *path)
+static int read_bg_from_eb(struct btrfs_fs_info *fs_info, const struct btrfs_key *key,
+			   const struct btrfs_path *path)
 {
 	struct btrfs_chunk_map *map;
 	struct btrfs_block_group_item bg;
@@ -2055,7 +2055,7 @@ static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
 
 static int find_first_block_group(struct btrfs_fs_info *fs_info,
 				  struct btrfs_path *path,
-				  struct btrfs_key *key)
+				  const struct btrfs_key *key)
 {
 	struct btrfs_root *root = btrfs_block_group_root(fs_info);
 	int ret;
@@ -2640,8 +2640,8 @@ static int insert_block_group_item(struct btrfs_trans_handle *trans,
 }
 
 static int insert_dev_extent(struct btrfs_trans_handle *trans,
-			    struct btrfs_device *device, u64 chunk_offset,
-			    u64 start, u64 num_bytes)
+			     const struct btrfs_device *device, u64 chunk_offset,
+			     u64 start, u64 num_bytes)
 {
 	struct btrfs_fs_info *fs_info = device->fs_info;
 	struct btrfs_root *root = fs_info->dev_root;
@@ -2817,7 +2817,7 @@ void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
  * For extent tree v2 we use the block_group_item->chunk_offset to point at our
  * global root id.  For v1 it's always set to BTRFS_FIRST_CHUNK_TREE_OBJECTID.
  */
-static u64 calculate_global_root_id(struct btrfs_fs_info *fs_info, u64 offset)
+static u64 calculate_global_root_id(const struct btrfs_fs_info *fs_info, u64 offset)
 {
 	u64 div = SZ_1G;
 	u64 index;
@@ -3842,8 +3842,8 @@ static void force_metadata_allocation(struct btrfs_fs_info *info)
 	}
 }
 
-static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
-			      struct btrfs_space_info *sinfo, int force)
+static int should_alloc_chunk(const struct btrfs_fs_info *fs_info,
+			      const struct btrfs_space_info *sinfo, int force)
 {
 	u64 bytes_used = btrfs_space_info_used(sinfo, false);
 	u64 thresh;
@@ -4218,7 +4218,7 @@ int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
 	return ret;
 }
 
-static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
+static u64 get_profile_num_devs(const struct btrfs_fs_info *fs_info, u64 type)
 {
 	u64 num_dev;
 
@@ -4622,7 +4622,7 @@ int btrfs_use_block_group_size_class(struct btrfs_block_group *bg,
 	return 0;
 }
 
-bool btrfs_block_group_should_use_size_class(struct btrfs_block_group *bg)
+bool btrfs_block_group_should_use_size_class(const struct btrfs_block_group *bg)
 {
 	if (btrfs_is_zoned(bg->fs_info))
 		return false;

fs/btrfs/block-group.h

@@ -266,7 +266,7 @@ struct btrfs_block_group {
 	u64 reclaim_mark;
 };
 
-static inline u64 btrfs_block_group_end(struct btrfs_block_group *block_group)
+static inline u64 btrfs_block_group_end(const struct btrfs_block_group *block_group)
 {
 	return (block_group->start + block_group->length);
 }
@@ -278,8 +278,7 @@ static inline bool btrfs_is_block_group_used(const struct btrfs_block_group *bg)
 	return (bg->used > 0 || bg->reserved > 0 || bg->pinned > 0);
 }
 
-static inline bool btrfs_is_block_group_data_only(
-					struct btrfs_block_group *block_group)
+static inline bool btrfs_is_block_group_data_only(const struct btrfs_block_group *block_group)
 {
 	/*
 	 * In mixed mode the fragmentation is expected to be high, lowering the
@@ -290,7 +289,7 @@ static inline bool btrfs_is_block_group_data_only(
 }
 
 #ifdef CONFIG_BTRFS_DEBUG
-int btrfs_should_fragment_free_space(struct btrfs_block_group *block_group);
+int btrfs_should_fragment_free_space(const struct btrfs_block_group *block_group);
 #endif
 
 struct btrfs_block_group *btrfs_lookup_first_block_group(
@@ -370,7 +369,7 @@ static inline u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
 	return btrfs_get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
 }
 
-static inline int btrfs_block_group_done(struct btrfs_block_group *cache)
+static inline int btrfs_block_group_done(const struct btrfs_block_group *cache)
 {
 	smp_mb();
 	return cache->cached == BTRFS_CACHE_FINISHED ||
@@ -387,6 +386,6 @@ enum btrfs_block_group_size_class btrfs_calc_block_group_size_class(u64 size);
 int btrfs_use_block_group_size_class(struct btrfs_block_group *bg,
 				     enum btrfs_block_group_size_class size_class,
 				     bool force_wrong_size_class);
-bool btrfs_block_group_should_use_size_class(struct btrfs_block_group *bg);
+bool btrfs_block_group_should_use_size_class(const struct btrfs_block_group *bg);
 
 #endif /* BTRFS_BLOCK_GROUP_H */

fs/btrfs/block-rsv.c

@@ -553,7 +553,7 @@ struct btrfs_block_rsv *btrfs_use_block_rsv(struct btrfs_trans_handle *trans,
 	return ERR_PTR(ret);
 }
 
-int btrfs_check_trunc_cache_free_space(struct btrfs_fs_info *fs_info,
+int btrfs_check_trunc_cache_free_space(const struct btrfs_fs_info *fs_info,
 				       struct btrfs_block_rsv *rsv)
 {
 	u64 needed_bytes;

fs/btrfs/block-rsv.h

@@ -89,7 +89,7 @@ void btrfs_release_global_block_rsv(struct btrfs_fs_info *fs_info);
 struct btrfs_block_rsv *btrfs_use_block_rsv(struct btrfs_trans_handle *trans,
 					    struct btrfs_root *root,
 					    u32 blocksize);
-int btrfs_check_trunc_cache_free_space(struct btrfs_fs_info *fs_info,
+int btrfs_check_trunc_cache_free_space(const struct btrfs_fs_info *fs_info,
 				       struct btrfs_block_rsv *rsv);
 static inline void btrfs_unuse_block_rsv(struct btrfs_fs_info *fs_info,
 					 struct btrfs_block_rsv *block_rsv,

fs/btrfs/ctree.c

@@ -2564,8 +2564,8 @@ int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key,
  *
  */
 static void fixup_low_keys(struct btrfs_trans_handle *trans,
-			   struct btrfs_path *path,
-			   struct btrfs_disk_key *key, int level)
+			   const struct btrfs_path *path,
+			   const struct btrfs_disk_key *key, int level)
 {
 	int i;
 	struct extent_buffer *t;
@@ -2594,7 +2594,7 @@ static void fixup_low_keys(struct btrfs_trans_handle *trans,
  * that the new key won't break the order
  */
 void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
-			     struct btrfs_path *path,
+			     const struct btrfs_path *path,
 			     const struct btrfs_key *new_key)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
@@ -2660,8 +2660,8 @@ void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
  * is correct, we only need to bother the last key of @left and the first
  * key of @right.
  */
-static bool check_sibling_keys(struct extent_buffer *left,
-			       struct extent_buffer *right)
+static bool check_sibling_keys(const struct extent_buffer *left,
+			       const struct extent_buffer *right)
 {
 	struct btrfs_key left_last;
 	struct btrfs_key right_first;
@@ -2928,8 +2928,8 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans,
  * blocknr is the block the key points to.
  */
 static int insert_ptr(struct btrfs_trans_handle *trans,
-		      struct btrfs_path *path,
-		      struct btrfs_disk_key *key, u64 bytenr,
+		      const struct btrfs_path *path,
+		      const struct btrfs_disk_key *key, u64 bytenr,
 		      int slot, int level)
 {
 	struct extent_buffer *lower;
@@ -4019,7 +4019,7 @@ int btrfs_split_item(struct btrfs_trans_handle *trans,
  * the front.
  */
 void btrfs_truncate_item(struct btrfs_trans_handle *trans,
-			 struct btrfs_path *path, u32 new_size, int from_end)
+			 const struct btrfs_path *path, u32 new_size, int from_end)
 {
 	int slot;
 	struct extent_buffer *leaf;
@@ -4111,7 +4111,7 @@ void btrfs_truncate_item(struct btrfs_trans_handle *trans,
  * make the item pointed to by the path bigger, data_size is the added size.
  */
 void btrfs_extend_item(struct btrfs_trans_handle *trans,
-		       struct btrfs_path *path, u32 data_size)
+		       const struct btrfs_path *path, u32 data_size)
 {
 	int slot;
 	struct extent_buffer *leaf;

fs/btrfs/ctree.h

@@ -538,7 +538,7 @@ int btrfs_previous_item(struct btrfs_root *root,
 int btrfs_previous_extent_item(struct btrfs_root *root,
 			struct btrfs_path *path, u64 min_objectid);
 void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
-			     struct btrfs_path *path,
+			     const struct btrfs_path *path,
 			     const struct btrfs_key *new_key);
 struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
 int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
@@ -572,9 +572,9 @@ bool btrfs_block_can_be_shared(struct btrfs_trans_handle *trans,
 int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		  struct btrfs_path *path, int level, int slot);
 void btrfs_extend_item(struct btrfs_trans_handle *trans,
-		       struct btrfs_path *path, u32 data_size);
+		       const struct btrfs_path *path, u32 data_size);
 void btrfs_truncate_item(struct btrfs_trans_handle *trans,
-			 struct btrfs_path *path, u32 new_size, int from_end);
+			 const struct btrfs_path *path, u32 new_size, int from_end);
 int btrfs_split_item(struct btrfs_trans_handle *trans,
 		     struct btrfs_root *root,
 		     struct btrfs_path *path,

fs/btrfs/discard.c

@@ -68,7 +68,7 @@ static int discard_minlen[BTRFS_NR_DISCARD_LISTS] = {
 };
 
 static struct list_head *get_discard_list(struct btrfs_discard_ctl *discard_ctl,
-					  struct btrfs_block_group *block_group)
+					  const struct btrfs_block_group *block_group)
 {
 	return &discard_ctl->discard_list[block_group->discard_index];
 }
@@ -80,7 +80,7 @@ static struct list_head *get_discard_list(struct btrfs_discard_ctl *discard_ctl,
  *
  * Check if the file system is writeable and BTRFS_FS_DISCARD_RUNNING is set.
  */
-static bool btrfs_run_discard_work(struct btrfs_discard_ctl *discard_ctl)
+static bool btrfs_run_discard_work(const struct btrfs_discard_ctl *discard_ctl)
 {
 	struct btrfs_fs_info *fs_info = container_of(discard_ctl,
 						     struct btrfs_fs_info,

fs/btrfs/file-item.c

@@ -151,7 +151,7 @@ static inline u32 max_ordered_sum_bytes(const struct btrfs_fs_info *fs_info)
  * Calculate the total size needed to allocate for an ordered sum structure
  * spanning @bytes in the file.
  */
-static int btrfs_ordered_sum_size(struct btrfs_fs_info *fs_info, unsigned long bytes)
+static int btrfs_ordered_sum_size(const struct btrfs_fs_info *fs_info, unsigned long bytes)
 {
 	return sizeof(struct btrfs_ordered_sum) + bytes_to_csum_size(fs_info, bytes);
 }
@@ -1272,7 +1272,7 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 
 void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
 				     const struct btrfs_path *path,
-				     struct btrfs_file_extent_item *fi,
+				     const struct btrfs_file_extent_item *fi,
 				     struct extent_map *em)
 {
 	struct btrfs_fs_info *fs_info = inode->root->fs_info;

fs/btrfs/file-item.h

@@ -74,7 +74,7 @@ int btrfs_lookup_csums_bitmap(struct btrfs_root *root, struct btrfs_path *path,
 			      unsigned long *csum_bitmap);
 void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
 				     const struct btrfs_path *path,
-				     struct btrfs_file_extent_item *fi,
+				     const struct btrfs_file_extent_item *fi,
 				     struct extent_map *em);
 int btrfs_inode_clear_file_extent_range(struct btrfs_inode *inode, u64 start,
 					u64 len);

fs/btrfs/inode-item.c

@@ -14,7 +14,7 @@
 #include "extent-tree.h"
 #include "file-item.h"
 
-struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
+struct btrfs_inode_ref *btrfs_find_name_in_backref(const struct extent_buffer *leaf,
 						   int slot,
 						   const struct fscrypt_str *name)
 {
@@ -42,7 +42,7 @@ struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
 }
 
 struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
-		struct extent_buffer *leaf, int slot, u64 ref_objectid,
+		const struct extent_buffer *leaf, int slot, u64 ref_objectid,
 		const struct fscrypt_str *name)
 {
 	struct btrfs_inode_extref *extref;
@@ -423,9 +423,9 @@ int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 	return ret;
 }
 
-static inline void btrfs_trace_truncate(struct btrfs_inode *inode,
-					struct extent_buffer *leaf,
-					struct btrfs_file_extent_item *fi,
+static inline void btrfs_trace_truncate(const struct btrfs_inode *inode,
+					const struct extent_buffer *leaf,
+					const struct btrfs_file_extent_item *fi,
 					u64 offset, int extent_type, int slot)
 {
 	if (!inode)

fs/btrfs/inode-item.h

@@ -109,11 +109,11 @@ struct btrfs_inode_extref *btrfs_lookup_inode_extref(
 			  u64 inode_objectid, u64 ref_objectid, int ins_len,
 			  int cow);
 
-struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
+struct btrfs_inode_ref *btrfs_find_name_in_backref(const struct extent_buffer *leaf,
 						   int slot,
 						   const struct fscrypt_str *name);
 struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
-		struct extent_buffer *leaf, int slot, u64 ref_objectid,
+		const struct extent_buffer *leaf, int slot, u64 ref_objectid,
 		const struct fscrypt_str *name);
 
 #endif

fs/btrfs/space-info.c

@@ -163,7 +163,7 @@
  *   thing with or without extra unallocated space.
  */
 
-u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
+u64 __pure btrfs_space_info_used(const struct btrfs_space_info *s_info,
 			  bool may_use_included)
 {
 	ASSERT(s_info);
@@ -368,7 +368,7 @@ static u64 calc_effective_data_chunk_size(struct btrfs_fs_info *fs_info)
 }
 
 static u64 calc_available_free_space(struct btrfs_fs_info *fs_info,
-			  struct btrfs_space_info *space_info,
+			  const struct btrfs_space_info *space_info,
 			  enum btrfs_reserve_flush_enum flush)
 {
 	u64 profile;
@@ -437,7 +437,7 @@ static u64 calc_available_free_space(struct btrfs_fs_info *fs_info,
 }
 
 int btrfs_can_overcommit(struct btrfs_fs_info *fs_info,
-			 struct btrfs_space_info *space_info, u64 bytes,
+			 const struct btrfs_space_info *space_info, u64 bytes,
 			 enum btrfs_reserve_flush_enum flush)
 {
 	u64 avail;
@@ -542,8 +542,8 @@ static void dump_global_block_rsv(struct btrfs_fs_info *fs_info)
 	DUMP_BLOCK_RSV(fs_info, delayed_refs_rsv);
 }
 
-static void __btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
-				    struct btrfs_space_info *info)
+static void __btrfs_dump_space_info(const struct btrfs_fs_info *fs_info,
+				    const struct btrfs_space_info *info)
 {
 	const char *flag_str = space_info_flag_to_str(info);
 	lockdep_assert_held(&info->lock);
@@ -844,9 +844,8 @@ static void flush_space(struct btrfs_fs_info *fs_info,
 	return;
 }
 
-static inline u64
-btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
-				 struct btrfs_space_info *space_info)
+static u64 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
+					    const struct btrfs_space_info *space_info)
 {
 	u64 used;
 	u64 avail;
@@ -871,7 +870,7 @@ btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
 }
 
 static bool need_preemptive_reclaim(struct btrfs_fs_info *fs_info,
-				    struct btrfs_space_info *space_info)
+				    const struct btrfs_space_info *space_info)
 {
 	const u64 global_rsv_size = btrfs_block_rsv_reserved(&fs_info->global_block_rsv);
 	u64 ordered, delalloc;
@@ -1943,7 +1942,7 @@ static u64 calc_unalloc_target(struct btrfs_fs_info *fs_info)
  * Typically with 10 block groups as the target, the discrete values this comes
  * out to are 0, 10, 20, ... , 80, 90, and 99.
  */
-static int calc_dynamic_reclaim_threshold(struct btrfs_space_info *space_info)
+static int calc_dynamic_reclaim_threshold(const struct btrfs_space_info *space_info)
 {
 	struct btrfs_fs_info *fs_info = space_info->fs_info;
 	u64 unalloc = atomic64_read(&fs_info->free_chunk_space);
@@ -1962,7 +1961,7 @@ static int calc_dynamic_reclaim_threshold(struct btrfs_space_info *space_info)
 	return calc_pct_ratio(want, target);
 }
 
-int btrfs_calc_reclaim_threshold(struct btrfs_space_info *space_info)
+int btrfs_calc_reclaim_threshold(const struct btrfs_space_info *space_info)
 {
 	lockdep_assert_held(&space_info->lock);
 
@@ -1985,7 +1984,7 @@ static bool is_reclaim_urgent(struct btrfs_space_info *space_info)
 	return unalloc < data_chunk_size;
 }
 
-static void do_reclaim_sweep(struct btrfs_fs_info *fs_info,
+static void do_reclaim_sweep(const struct btrfs_fs_info *fs_info,
 			     struct btrfs_space_info *space_info, int raid)
 {
 	struct btrfs_block_group *bg;
@@ -2073,7 +2072,7 @@ bool btrfs_should_periodic_reclaim(struct btrfs_space_info *space_info)
 	return ret;
 }
 
-void btrfs_reclaim_sweep(struct btrfs_fs_info *fs_info)
+void btrfs_reclaim_sweep(const struct btrfs_fs_info *fs_info)
 {
 	int raid;
 	struct btrfs_space_info *space_info;

fs/btrfs/space-info.h

@@ -217,7 +217,7 @@ struct reserve_ticket {
 	wait_queue_head_t wait;
 };
 
-static inline bool btrfs_mixed_space_info(struct btrfs_space_info *space_info)
+static inline bool btrfs_mixed_space_info(const struct btrfs_space_info *space_info)
 {
 	return ((space_info->flags & BTRFS_BLOCK_GROUP_METADATA) &&
 		(space_info->flags & BTRFS_BLOCK_GROUP_DATA));
@@ -258,7 +258,7 @@ void btrfs_update_space_info_chunk_size(struct btrfs_space_info *space_info,
 					u64 chunk_size);
 struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info,
 					       u64 flags);
-u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
+u64 __pure btrfs_space_info_used(const struct btrfs_space_info *s_info,
 			  bool may_use_included);
 void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
 void btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
@@ -271,7 +271,7 @@ int btrfs_reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
 void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info,
 				struct btrfs_space_info *space_info);
 int btrfs_can_overcommit(struct btrfs_fs_info *fs_info,
-			 struct btrfs_space_info *space_info, u64 bytes,
+			 const struct btrfs_space_info *space_info, u64 bytes,
 			 enum btrfs_reserve_flush_enum flush);
 
 static inline void btrfs_space_info_free_bytes_may_use(
@@ -293,7 +293,7 @@ u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo);
 void btrfs_space_info_update_reclaimable(struct btrfs_space_info *space_info, s64 bytes);
 void btrfs_set_periodic_reclaim_ready(struct btrfs_space_info *space_info, bool ready);
 bool btrfs_should_periodic_reclaim(struct btrfs_space_info *space_info);
-int btrfs_calc_reclaim_threshold(struct btrfs_space_info *space_info);
-void btrfs_reclaim_sweep(struct btrfs_fs_info *fs_info);
+int btrfs_calc_reclaim_threshold(const struct btrfs_space_info *space_info);
+void btrfs_reclaim_sweep(const struct btrfs_fs_info *fs_info);
 
 #endif /* BTRFS_SPACE_INFO_H */

fs/btrfs/tree-mod-log.c

@@ -170,7 +170,7 @@ static noinline int tree_mod_log_insert(struct btrfs_fs_info *fs_info,
  * this until all tree mod log insertions are recorded in the rb tree and then
  * write unlock fs_info::tree_mod_log_lock.
  */
-static bool tree_mod_dont_log(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
+static bool tree_mod_dont_log(struct btrfs_fs_info *fs_info, const struct extent_buffer *eb)
 {
 	if (!test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags))
 		return true;
@@ -188,7 +188,7 @@ static bool tree_mod_dont_log(struct btrfs_fs_info *fs_info, struct extent_buffe
 
 /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
 static bool tree_mod_need_log(const struct btrfs_fs_info *fs_info,
-				    struct extent_buffer *eb)
+			      const struct extent_buffer *eb)
 {
 	if (!test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags))
 		return false;
@@ -198,7 +198,7 @@ static bool tree_mod_need_log(const struct btrfs_fs_info *fs_info,
 	return true;
 }
 
-static struct tree_mod_elem *alloc_tree_mod_elem(struct extent_buffer *eb,
+static struct tree_mod_elem *alloc_tree_mod_elem(const struct extent_buffer *eb,
 						 int slot,
 						 enum btrfs_mod_log_op op)
 {
@@ -221,7 +221,7 @@ static struct tree_mod_elem *alloc_tree_mod_elem(struct extent_buffer *eb,
 	return tm;
 }
 
-int btrfs_tree_mod_log_insert_key(struct extent_buffer *eb, int slot,
+int btrfs_tree_mod_log_insert_key(const struct extent_buffer *eb, int slot,
 				  enum btrfs_mod_log_op op)
 {
 	struct tree_mod_elem *tm;
@@ -258,7 +258,7 @@ int btrfs_tree_mod_log_insert_key(struct extent_buffer *eb, int slot,
 	return ret;
 }
 
-static struct tree_mod_elem *tree_mod_log_alloc_move(struct extent_buffer *eb,
+static struct tree_mod_elem *tree_mod_log_alloc_move(const struct extent_buffer *eb,
 						     int dst_slot, int src_slot,
 						     int nr_items)
 {
@@ -278,7 +278,7 @@ static struct tree_mod_elem *tree_mod_log_alloc_move(struct extent_buffer *eb,
 	return tm;
 }
 
-int btrfs_tree_mod_log_insert_move(struct extent_buffer *eb,
+int btrfs_tree_mod_log_insert_move(const struct extent_buffer *eb,
 				   int dst_slot, int src_slot,
 				   int nr_items)
 {
@@ -535,7 +535,7 @@ static struct tree_mod_elem *tree_mod_log_search(struct btrfs_fs_info *fs_info,
 }
 
 int btrfs_tree_mod_log_eb_copy(struct extent_buffer *dst,
-			       struct extent_buffer *src,
+			       const struct extent_buffer *src,
 			       unsigned long dst_offset,
 			       unsigned long src_offset,
 			       int nr_items)

fs/btrfs/tree-mod-log.h

@@ -37,7 +37,7 @@ void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
 int btrfs_tree_mod_log_insert_root(struct extent_buffer *old_root,
 				   struct extent_buffer *new_root,
 				   bool log_removal);
-int btrfs_tree_mod_log_insert_key(struct extent_buffer *eb, int slot,
+int btrfs_tree_mod_log_insert_key(const struct extent_buffer *eb, int slot,
 				  enum btrfs_mod_log_op op);
 int btrfs_tree_mod_log_free_eb(struct extent_buffer *eb);
 struct extent_buffer *btrfs_tree_mod_log_rewind(struct btrfs_fs_info *fs_info,
@@ -47,11 +47,11 @@ struct extent_buffer *btrfs_tree_mod_log_rewind(struct btrfs_fs_info *fs_info,
 struct extent_buffer *btrfs_get_old_root(struct btrfs_root *root, u64 time_seq);
 int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq);
 int btrfs_tree_mod_log_eb_copy(struct extent_buffer *dst,
-			       struct extent_buffer *src,
+			       const struct extent_buffer *src,
 			       unsigned long dst_offset,
 			       unsigned long src_offset,
 			       int nr_items);
-int btrfs_tree_mod_log_insert_move(struct extent_buffer *eb,
+int btrfs_tree_mod_log_insert_move(const struct extent_buffer *eb,
 				   int dst_slot, int src_slot,
 				   int nr_items);
 u64 btrfs_tree_mod_log_lowest_seq(struct btrfs_fs_info *fs_info);

fs/btrfs/zoned.c

@@ -2459,7 +2459,7 @@ void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info)
 	mutex_unlock(&fs_devices->device_list_mutex);
 }
 
-bool btrfs_zoned_should_reclaim(struct btrfs_fs_info *fs_info)
+bool btrfs_zoned_should_reclaim(const struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 	struct btrfs_device *device;

fs/btrfs/zoned.h

@@ -89,7 +89,7 @@ void btrfs_schedule_zone_finish_bg(struct btrfs_block_group *bg,
 				   struct extent_buffer *eb);
 void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg);
 void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info);
-bool btrfs_zoned_should_reclaim(struct btrfs_fs_info *fs_info);
+bool btrfs_zoned_should_reclaim(const struct btrfs_fs_info *fs_info);
 void btrfs_zoned_release_data_reloc_bg(struct btrfs_fs_info *fs_info, u64 logical,
 				       u64 length);
 int btrfs_zone_finish_one_bg(struct btrfs_fs_info *fs_info);
@@ -242,7 +242,7 @@ static inline void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg) { }
 
 static inline void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info) { }
 
-static inline bool btrfs_zoned_should_reclaim(struct btrfs_fs_info *fs_info)
+static inline bool btrfs_zoned_should_reclaim(const struct btrfs_fs_info *fs_info)
 {
 	return false;
 }

include/trace/events/btrfs.h

@@ -1825,7 +1825,7 @@ TRACE_EVENT(qgroup_update_counters,
 
 TRACE_EVENT(qgroup_update_reserve,
 
-	TP_PROTO(struct btrfs_fs_info *fs_info, struct btrfs_qgroup *qgroup,
+	TP_PROTO(const struct btrfs_fs_info *fs_info, const struct btrfs_qgroup *qgroup,
 		 s64 diff, int type),
 
 	TP_ARGS(fs_info, qgroup, diff, type),
@@ -1851,7 +1851,7 @@ TRACE_EVENT(qgroup_update_reserve,
 
 TRACE_EVENT(qgroup_meta_reserve,
 
-	TP_PROTO(struct btrfs_root *root, s64 diff, int type),
+	TP_PROTO(const struct btrfs_root *root, s64 diff, int type),
 
 	TP_ARGS(root, diff, type),
 
@@ -1874,7 +1874,7 @@ TRACE_EVENT(qgroup_meta_reserve,
 
 TRACE_EVENT(qgroup_meta_convert,
 
-	TP_PROTO(struct btrfs_root *root, s64 diff),
+	TP_PROTO(const struct btrfs_root *root, s64 diff),
 
 	TP_ARGS(root, diff),