btrfs: reuse existing pointers from btrfs_ioctl

btrfs_ioctl already contains pointers to the inode and btrfs_root
structs, so we can pass them into the subfunctions instead of the
toplevel struct file.
Signed-off-by: Sahil Kang <sahil.kang@asilaycomputing.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ioctl.c

@@ -440,10 +440,8 @@ void btrfs_exclop_balance(struct btrfs_fs_info *fs_info,
 	}
 }
 
-static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
+static int btrfs_ioctl_getversion(struct inode *inode, int __user *arg)
 {
-	struct inode *inode = file_inode(file);
-
 	return put_user(inode->i_generation, arg);
 }
 
@@ -2871,25 +2869,22 @@ static int btrfs_search_path_in_tree_user(struct user_namespace *mnt_userns,
 	return ret;
 }
 
-static noinline int btrfs_ioctl_ino_lookup(struct file *file,
+static noinline int btrfs_ioctl_ino_lookup(struct btrfs_root *root,
 					   void __user *argp)
 {
 	struct btrfs_ioctl_ino_lookup_args *args;
-	struct inode *inode;
 	int ret = 0;
 
 	args = memdup_user(argp, sizeof(*args));
 	if (IS_ERR(args))
 		return PTR_ERR(args);
 
-	inode = file_inode(file);
-
 	/*
 	 * Unprivileged query to obtain the containing subvolume root id. The
 	 * path is reset so it's consistent with btrfs_search_path_in_tree.
 	 */
 	if (args->treeid == 0)
-		args->treeid = BTRFS_I(inode)->root->root_key.objectid;
+		args->treeid = root->root_key.objectid;
 
 	if (args->objectid == BTRFS_FIRST_FREE_OBJECTID) {
 		args->name[0] = 0;
@@ -2901,7 +2896,7 @@ static noinline int btrfs_ioctl_ino_lookup(struct file *file,
 		goto out;
 	}
 
-	ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
+	ret = btrfs_search_path_in_tree(root->fs_info,
 					args->treeid, args->objectid,
 					args->name);
 
@@ -3077,7 +3072,8 @@ static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
  * Return ROOT_REF information of the subvolume containing this inode
  * except the subvolume name.
  */
-static int btrfs_ioctl_get_subvol_rootref(struct file *file, void __user *argp)
+static int btrfs_ioctl_get_subvol_rootref(struct btrfs_root *subvol_root,
+					  void __user *argp)
 {
 	struct btrfs_ioctl_get_subvol_rootref_args *rootrefs;
 	struct btrfs_root_ref *rref;
@@ -3085,7 +3081,6 @@ static int btrfs_ioctl_get_subvol_rootref(struct file *file, void __user *argp)
 	struct btrfs_path *path;
 	struct btrfs_key key;
 	struct extent_buffer *leaf;
-	struct inode *inode;
 	u64 objectid;
 	int slot;
 	int ret;
@@ -3101,9 +3096,8 @@ static int btrfs_ioctl_get_subvol_rootref(struct file *file, void __user *argp)
 		return PTR_ERR(rootrefs);
 	}
 
-	inode = file_inode(file);
-	root = BTRFS_I(inode)->root->fs_info->tree_root;
-	objectid = BTRFS_I(inode)->root->root_key.objectid;
+	root = subvol_root->fs_info->tree_root;
+	objectid = subvol_root->root_key.objectid;
 
 	key.objectid = objectid;
 	key.type = BTRFS_ROOT_REF_KEY;
@@ -5194,7 +5188,7 @@ long btrfs_ioctl(struct file *file, unsigned int
 
 	switch (cmd) {
 	case FS_IOC_GETVERSION:
-		return btrfs_ioctl_getversion(file, argp);
+		return btrfs_ioctl_getversion(inode, argp);
 	case FS_IOC_GETFSLABEL:
 		return btrfs_ioctl_get_fslabel(fs_info, argp);
 	case FS_IOC_SETFSLABEL:
@@ -5242,7 +5236,7 @@ long btrfs_ioctl(struct file *file, unsigned int
 	case BTRFS_IOC_TREE_SEARCH_V2:
 		return btrfs_ioctl_tree_search_v2(file, argp);
 	case BTRFS_IOC_INO_LOOKUP:
-		return btrfs_ioctl_ino_lookup(file, argp);
+		return btrfs_ioctl_ino_lookup(root, argp);
 	case BTRFS_IOC_INO_PATHS:
 		return btrfs_ioctl_ino_to_path(root, argp);
 	case BTRFS_IOC_LOGICAL_INO:
@@ -5321,7 +5315,7 @@ long btrfs_ioctl(struct file *file, unsigned int
 	case BTRFS_IOC_GET_SUBVOL_INFO:
 		return btrfs_ioctl_get_subvol_info(file, argp);
 	case BTRFS_IOC_GET_SUBVOL_ROOTREF:
-		return btrfs_ioctl_get_subvol_rootref(file, argp);
+		return btrfs_ioctl_get_subvol_rootref(root, argp);
 	case BTRFS_IOC_INO_LOOKUP_USER:
 		return btrfs_ioctl_ino_lookup_user(file, argp);
 	case FS_IOC_ENABLE_VERITY: