// SPDX-License-Identifier: GPL-2.0 #include <linux/fs.h>#include <linux/types.h>#include "ctree.h"#include "disk-io.h"#include "btrfs_inode.h"#include "export.h"#include "accessors.h"#include "super.h" #define BTRFS_FID_SIZE_NON_CONNECTABLE (offsetof(struct btrfs_fid, \						 parent_objectid) / 4)#define BTRFS_FID_SIZE_CONNECTABLE (offsetof(struct btrfs_fid, \					     parent_root_objectid) / 4)#define BTRFS_FID_SIZE_CONNECTABLE_ROOT (sizeof(struct btrfs_fid) / 4) static int btrfs_encode_fh(struct inode *inode, u32 *fh, int *max_len,			   struct inode *parent){	struct btrfs_fid *fid = (struct btrfs_fid *)fh;	int len = *max_len;	int type; 	if (parent && (len < BTRFS_FID_SIZE_CONNECTABLE)) {		if (btrfs_root_id(BTRFS_I(inode)->root) !=		    btrfs_root_id(BTRFS_I(parent)->root))			*max_len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;		else			*max_len = BTRFS_FID_SIZE_CONNECTABLE;		return FILEID_INVALID;	} else if (len < BTRFS_FID_SIZE_NON_CONNECTABLE) {		*max_len = BTRFS_FID_SIZE_NON_CONNECTABLE;		return FILEID_INVALID;	} 	len  = BTRFS_FID_SIZE_NON_CONNECTABLE;	type = FILEID_BTRFS_WITHOUT_PARENT; 	fid->objectid = btrfs_ino(BTRFS_I(inode));	fid->root_objectid = btrfs_root_id(BTRFS_I(inode)->root);	fid->gen = inode->i_generation; 	if (parent) {		u64 parent_root_id; 		fid->parent_objectid = btrfs_ino(BTRFS_I(parent));		fid->parent_gen = parent->i_generation;		parent_root_id = btrfs_root_id(BTRFS_I(parent)->root); 		if (parent_root_id != fid->root_objectid) {			if (*max_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)				return FILEID_INVALID;			fid->parent_root_objectid = parent_root_id;			len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;			type = FILEID_BTRFS_WITH_PARENT_ROOT;		} else {			len = BTRFS_FID_SIZE_CONNECTABLE;			type = FILEID_BTRFS_WITH_PARENT;		}	} 	*max_len = len;	return type;} /* * Read dentry of inode with @objectid from filesystem root @root_objectid. * * @sb:             the filesystem super block * @objectid:       inode objectid * @root_objectid:  object id of the subvolume root where to look up the inode * @generation:     optional, if not zero, verify that the found inode *                  generation matches * * Return dentry alias for the inode, otherwise an error. In case the * generation does not match return ESTALE. */struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,				u64 root_objectid, u64 generation){	struct btrfs_fs_info *fs_info = btrfs_sb(sb);	struct btrfs_root *root;	struct btrfs_inode *inode; 	if (objectid < BTRFS_FIRST_FREE_OBJECTID)		return ERR_PTR(-ESTALE); 	root = btrfs_get_fs_root(fs_info, root_objectid, true);	if (IS_ERR(root))		return ERR_CAST(root); 	inode = btrfs_iget(objectid, root);	btrfs_put_root(root);	if (IS_ERR(inode))		return ERR_CAST(inode); 	if (generation != 0 && generation != inode->vfs_inode.i_generation) {		iput(&inode->vfs_inode);		return ERR_PTR(-ESTALE);	} 	return d_obtain_alias(&inode->vfs_inode);} static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,					 int fh_len, int fh_type){	struct btrfs_fid *fid = (struct btrfs_fid *) fh;	u64 objectid, root_objectid;	u32 generation; 	if (fh_type == FILEID_BTRFS_WITH_PARENT) {		if (fh_len <  BTRFS_FID_SIZE_CONNECTABLE)			return NULL;		root_objectid = fid->root_objectid;	} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {		if (fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT)			return NULL;		root_objectid = fid->parent_root_objectid;	} else		return NULL; 	objectid = fid->parent_objectid;	generation = fid->parent_gen; 	return btrfs_get_dentry(sb, objectid, root_objectid, generation);} static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,					 int fh_len, int fh_type){	struct btrfs_fid *fid = (struct btrfs_fid *) fh;	u64 objectid, root_objectid;	u32 generation; 	if ((fh_type != FILEID_BTRFS_WITH_PARENT ||	     fh_len < BTRFS_FID_SIZE_CONNECTABLE) &&	    (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||	     fh_len < BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&	    (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||	     fh_len < BTRFS_FID_SIZE_NON_CONNECTABLE))		return NULL; 	objectid = fid->objectid;	root_objectid = fid->root_objectid;	generation = fid->gen; 	return btrfs_get_dentry(sb, objectid, root_objectid, generation);} struct dentry *btrfs_get_parent(struct dentry *child){	struct btrfs_inode *dir = BTRFS_I(d_inode(child));	struct btrfs_inode *inode;	struct btrfs_root *root = dir->root;	struct btrfs_fs_info *fs_info = root->fs_info;	struct btrfs_path *path;	struct extent_buffer *leaf;	struct btrfs_root_ref *ref;	struct btrfs_key key;	struct btrfs_key found_key;	int ret; 	path = btrfs_alloc_path();	if (!path)		return ERR_PTR(-ENOMEM); 	if (btrfs_ino(dir) == BTRFS_FIRST_FREE_OBJECTID) {		key.objectid = btrfs_root_id(root);		key.type = BTRFS_ROOT_BACKREF_KEY;		key.offset = (u64)-1;		root = fs_info->tree_root;	} else {		key.objectid = btrfs_ino(dir);		key.type = BTRFS_INODE_REF_KEY;		key.offset = (u64)-1;	} 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);	if (ret < 0)		goto fail;	if (unlikely(ret == 0)) {		/*		 * Key with offset of -1 found, there would have to exist an		 * inode with such number or a root with such id.		 */		ret = -EUCLEAN;		goto fail;	} 	if (path->slots[0] == 0) {		ret = -ENOENT;		goto fail;	} 	path->slots[0]--;	leaf = path->nodes[0]; 	btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);	if (found_key.objectid != key.objectid || found_key.type != key.type) {		ret = -ENOENT;		goto fail;	} 	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {		ref = btrfs_item_ptr(leaf, path->slots[0],				     struct btrfs_root_ref);		key.objectid = btrfs_root_ref_dirid(leaf, ref);	} else {		key.objectid = found_key.offset;	}	btrfs_free_path(path); 	if (found_key.type == BTRFS_ROOT_BACKREF_KEY) {		return btrfs_get_dentry(fs_info->sb, key.objectid,					found_key.offset, 0);	} 	inode = btrfs_iget(key.objectid, root);	if (IS_ERR(inode))		return ERR_CAST(inode); 	return d_obtain_alias(&inode->vfs_inode);fail:	btrfs_free_path(path);	return ERR_PTR(ret);} static int btrfs_get_name(struct dentry *parent, char *name,			  struct dentry *child){	struct btrfs_inode *inode = BTRFS_I(d_inode(child));	struct btrfs_inode *dir = BTRFS_I(d_inode(parent));	struct btrfs_root *root = dir->root;	struct btrfs_fs_info *fs_info = root->fs_info;	BTRFS_PATH_AUTO_FREE(path);	struct btrfs_inode_ref *iref;	struct btrfs_root_ref *rref;	struct extent_buffer *leaf;	unsigned long name_ptr;	struct btrfs_key key;	int name_len;	int ret;	u64 ino; 	if (!S_ISDIR(dir->vfs_inode.i_mode))		return -EINVAL; 	ino = btrfs_ino(inode); 	path = btrfs_alloc_path();	if (!path)		return -ENOMEM; 	if (ino == BTRFS_FIRST_FREE_OBJECTID) {		key.objectid = btrfs_root_id(inode->root);		key.type = BTRFS_ROOT_BACKREF_KEY;		key.offset = (u64)-1;		root = fs_info->tree_root;	} else {		key.objectid = ino;		key.type = BTRFS_INODE_REF_KEY;		key.offset = btrfs_ino(dir);	} 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);	if (ret < 0) {		return ret;	} else if (ret > 0) {		if (ino == BTRFS_FIRST_FREE_OBJECTID)			path->slots[0]--;		else			return -ENOENT;	}	leaf = path->nodes[0]; 	if (ino == BTRFS_FIRST_FREE_OBJECTID) {		rref = btrfs_item_ptr(leaf, path->slots[0],				     struct btrfs_root_ref);		name_ptr = (unsigned long)(rref + 1);		name_len = btrfs_root_ref_name_len(leaf, rref);	} else {		iref = btrfs_item_ptr(leaf, path->slots[0],				      struct btrfs_inode_ref);		name_ptr = (unsigned long)(iref + 1);		name_len = btrfs_inode_ref_name_len(leaf, iref);	} 	read_extent_buffer(leaf, name, name_ptr, name_len); 	/*	 * have to add the null termination to make sure that reconnect_path	 * gets the right len for strlen	 */	name[name_len] = '\0'; 	return 0;} const struct export_operations btrfs_export_ops = {	.encode_fh	= btrfs_encode_fh,	.fh_to_dentry	= btrfs_fh_to_dentry,	.fh_to_parent	= btrfs_fh_to_parent,	.get_parent	= btrfs_get_parent,	.get_name	= btrfs_get_name,};