btrfs-progs: consitfy keys passed to serch functions

When using gcc8 to compile btrfs-progs, it complains as below:

ctree.c: In function 'btrfs_search_slot_for_read':
    ctree.c:1249:45: warning: passing argument 3 of 'btrfs_search_slot'
    discards 'const' qualifier from pointer target type
    [-Wdiscarded-qualifiers]
             ret = btrfs_search_slot(NULL, root, key, p, 0, 0);

Change btrfs_search_slot prototype with 'const' qualifier for argument 3.
Also fix similar problems as above change.

Signed-off-by: Su Yanjun <suyj.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

2 files changed, 15 insertions, 14 deletions

diff --git a/ctree.c b/ctree.c
index 1afb94f0..292c2e4f 100644
--- a/ctree.c
+++ b/ctree.c
@@ -27,7 +27,7 @@
 static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
 		      *root, struct btrfs_path *path, int level);
 static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
-		      *root, struct btrfs_key *ins_key,
+		      *root, const struct btrfs_key *ins_key,
 		      struct btrfs_path *path, int data_size, int extend);
 static int push_node_left(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *root, struct extent_buffer *dst,
@@ -389,7 +389,7 @@ int btrfs_cow_block(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2)
+int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2)
 {
 	if (k1->objectid > k2->objectid)
 		return 1;
@@ -409,7 +409,8 @@ int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2)
 /*
  * compare two keys in a memcmp fashion
  */
-static int btrfs_comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
+static int btrfs_comp_keys(struct btrfs_disk_key *disk,
+		const struct btrfs_key *k2)
 {
 	struct btrfs_key k1;
 
@@ -602,7 +603,7 @@ static int noinline check_block(struct btrfs_root *root,
  * slot may point to max if the key is bigger than all of the keys
  */
 static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
-			      int item_size, struct btrfs_key *key,
+			      int item_size, const struct btrfs_key *key,
 			      int max, int *slot)
 {
 	int low = 0;
@@ -636,7 +637,7 @@ static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
  * simple bin_search frontend that does the right thing for
  * leaves vs nodes
  */
-static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
+static int bin_search(struct extent_buffer *eb, const struct btrfs_key *key,
 		      int level, int *slot)
 {
 	if (level == 0)
@@ -1129,9 +1130,9 @@ out:
  * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
  * possible)
  */
-int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
-		      *root, struct btrfs_key *key, struct btrfs_path *p, int
-		      ins_len, int cow)
+int btrfs_search_slot(struct btrfs_trans_handle *trans,
+		struct btrfs_root *root, const struct btrfs_key *key,
+		struct btrfs_path *p, int ins_len, int cow)
 {
 	struct extent_buffer *b;
 	int slot;
@@ -2147,7 +2148,7 @@ static noinline int copy_for_split(struct btrfs_trans_handle *trans,
  */
 static noinline int split_leaf(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *root,
-			       struct btrfs_key *ins_key,
+			       const struct btrfs_key *ins_key,
 			       struct btrfs_path *path, int data_size,
 			       int extend)
 {
diff --git a/ctree.h b/ctree.h
index 3c396e7d..2d45d93b 100644
--- a/ctree.h
+++ b/ctree.h
@@ -1984,7 +1984,7 @@ static inline void btrfs_disk_key_to_cpu(struct btrfs_key *cpu,
 }
 
 static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
-					 struct btrfs_key *cpu)
+					 const struct btrfs_key *cpu)
 {
 	disk->offset = cpu_to_le64(cpu->offset);
 	disk->type = cpu->type;
@@ -2563,7 +2563,7 @@ u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset);
 
 /* ctree.c */
-int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2);
+int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2);
 int btrfs_del_ptr(struct btrfs_root *root, struct btrfs_path *path,
 		int level, int slot);
 enum btrfs_tree_block_status
@@ -2606,9 +2606,9 @@ int btrfs_split_item(struct btrfs_trans_handle *trans,
 		     struct btrfs_path *path,
 		     struct btrfs_key *new_key,
 		     unsigned long split_offset);
-int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
-		      *root, struct btrfs_key *key, struct btrfs_path *p, int
-		      ins_len, int cow);
+int btrfs_search_slot(struct btrfs_trans_handle *trans,
+		struct btrfs_root *root, const struct btrfs_key *key,
+		struct btrfs_path *p, int ins_len, int cow);
 int btrfs_search_slot_for_read(struct btrfs_root *root,
                                const struct btrfs_key *key,
                                struct btrfs_path *p, int find_higher,