A data access method in a file system, comprising: receiving a data access request, wherein the data access request comprises an identifier of a to-be-accessed node; obtaining access permission for the to-be-accessed node based on the identifier of the to-be-accessed node, wherein when a permission version number of the to-be-accessed node is not the latest in permission version numbers of all nodes indicated by path information of the to-be-accessed node, the access permission for the to-be-accessed node inherits a permission record corresponding to a parent node that is of the to-be-accessed node and that has a latest permission version number; and performing authentication based on the access permission for the to-be-accessed node, and accessing data of the to-be-accessed node after the authentication succeeds; wherein the method further comprises: selecting and comparing, by a storage system starting from the root node, permission version numbers of two nodes each time from all the nodes indicated by the path information of the to-be-accessed node, to determine a node with a newer permission version number; and determining, until the to-be-accessed node is compared through traversal in descending order of the directory levels, that a node with a newer permission version number is the node with the latest permission version number; characterised by receiving a node creation request, wherein the node creation request comprises an identifier and path information of a newly added node of the directory tree, and the path information of the newly added node indicates all nodes on an access branch from the root node to the newly added node; storing a correspondence between the identifier and the path information of the newly added node of the directory tree into a global access control list; and setting an initial permission version number for the newly added node, wherein the initial permission version number that is set for the newly added node is less than or equal to an initial global version parameter. receiving a data access request, wherein the data access request comprises an identifier of a to-be-accessed node; obtaining access permission for the to-be-accessed node based on the identifier of the to-be-accessed node, wherein when a permission version number of the to-be-accessed node is not the latest in permission version numbers of all nodes indicated by path information of the to-be-accessed node, the access permission for the to-be-accessed node inherits a permission record corresponding to a parent node that is of the to-be-accessed node and that has a latest permission version number; and performing authentication based on the access permission for the to-be-accessed node, and accessing data of the to-be-accessed node after the authentication succeeds; wherein the method further comprises: selecting and comparing, by a storage system starting from the root node, permission version numbers of two nodes each time from all the nodes indicated by the path information of the to-be-accessed node, to determine a node with a newer permission version number; and determining, until the to-be-accessed node is compared through traversal in descending order of the directory levels, that a node with a newer permission version number is the node with the latest permission version number; characterised by receiving a node creation request, wherein the node creation request comprises an identifier and path information of a newly added node of the directory tree, and the path information of the newly added node indicates all nodes on an access branch from the root node to the newly added node; storing a correspondence between the identifier and the path information of the newly added node of the directory tree into a global access control list; and setting an initial permission version number for the newly added node, wherein the initial permission version number that is set for the newly added node is less than or equal to an initial global version parameter. selecting and comparing, by a storage system starting from the root node, permission version numbers of two nodes each time from all the nodes indicated by the path information of the to-be-accessed node, to determine a node with a newer permission version number; and determining, until the to-be-accessed node is compared through traversal in descending order of the directory levels, that a node with a newer permission version number is the node with the latest permission version number; characterised by receiving a node creation request, wherein the node creation request comprises an identifier and path information of a newly added node of the directory tree, and the path information of the newly added node indicates all nodes on an access branch from the root node to the newly added node; storing a correspondence between the identifier and the path information of the newly added node of the directory tree into a global access control list; and setting an initial permission version number for the newly added node, wherein the initial permission version number that is set for the newly added node is less than or equal to an initial global version parameter.