diff options
Diffstat (limited to 'Documentation/filesystems/autofs4.txt')
| -rw-r--r-- | Documentation/filesystems/autofs4.txt | 39 |
1 files changed, 24 insertions, 15 deletions
diff --git a/Documentation/filesystems/autofs4.txt b/Documentation/filesystems/autofs4.txt index 8fac3fe7b8c9..f10dd590f69f 100644 --- a/Documentation/filesystems/autofs4.txt +++ b/Documentation/filesystems/autofs4.txt @@ -65,7 +65,7 @@ directory is a mount trap only if the filesystem is mounted *direct* and the root is empty. Directories created in the root directory are mount traps only if the -filesystem is mounted *indirect* and they are empty. +filesystem is mounted *indirect* and they are empty. Directories further down the tree depend on the *maxproto* mount option and particularly whether it is less than five or not. @@ -352,7 +352,7 @@ Communicating with autofs: root directory ioctls ------------------------------------------------ The root directory of an autofs filesystem will respond to a number of -ioctls. The process issuing the ioctl must have the CAP_SYS_ADMIN +ioctls. The process issuing the ioctl must have the CAP_SYS_ADMIN capability, or must be the automount daemon. The available ioctl commands are: @@ -425,8 +425,20 @@ Each ioctl is passed a pointer to an `autofs_dev_ioctl` structure: * including this struct */ __s32 ioctlfd; /* automount command fd */ - __u32 arg1; /* Command parameters */ - __u32 arg2; + /* Command parameters */ + union { + struct args_protover protover; + struct args_protosubver protosubver; + struct args_openmount openmount; + struct args_ready ready; + struct args_fail fail; + struct args_setpipefd setpipefd; + struct args_timeout timeout; + struct args_requester requester; + struct args_expire expire; + struct args_askumount askumount; + struct args_ismountpoint ismountpoint; + }; char path[0]; }; @@ -446,25 +458,22 @@ Commands are: set version numbers. - **AUTOFS_DEV_IOCTL_OPENMOUNT_CMD**: return an open file descriptor on the root of an autofs filesystem. The filesystem is identified - by name and device number, which is stored in `arg1`. Device - numbers for existing filesystems can be found in + by name and device number, which is stored in `openmount.devid`. + Device numbers for existing filesystems can be found in `/proc/self/mountinfo`. - **AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD**: same as `close(ioctlfd)`. - **AUTOFS_DEV_IOCTL_SETPIPEFD_CMD**: if the filesystem is in catatonic mode, this can provide the write end of a new pipe - in `arg1` to re-establish communication with a daemon. The - process group of the calling process is used to identify the + in `setpipefd.pipefd` to re-establish communication with a daemon. + The process group of the calling process is used to identify the daemon. - **AUTOFS_DEV_IOCTL_REQUESTER_CMD**: `path` should be a name within the filesystem that has been auto-mounted on. - arg1 is the dev number of the underlying autofs. On successful - return, `arg1` and `arg2` will be the UID and GID of the process - which triggered that mount. - + On successful return, `requester.uid` and `requester.gid` will be + the UID and GID of the process which triggered that mount. - **AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD**: Check if path is a mountpoint of a particular type - see separate documentation for details. - - **AUTOFS_DEV_IOCTL_PROTOVER_CMD**: - **AUTOFS_DEV_IOCTL_PROTOSUBVER_CMD**: - **AUTOFS_DEV_IOCTL_READY_CMD**: @@ -474,7 +483,7 @@ Commands are: - **AUTOFS_DEV_IOCTL_EXPIRE_CMD**: - **AUTOFS_DEV_IOCTL_ASKUMOUNT_CMD**: These all have the same function as the similarly named **AUTOFS_IOC** ioctls, except - that **FAIL** can be given an explicit error number in `arg1` + that **FAIL** can be given an explicit error number in `fail.status` instead of assuming `ENOENT`, and this **EXPIRE** command corresponds to **AUTOFS_IOC_EXPIRE_MULTI**. @@ -512,7 +521,7 @@ always be mounted "shared". e.g. > `mount --make-shared /autofs/mount/point` -The automount daemon is only able to mange a single mount location for +The automount daemon is only able to manage a single mount location for an autofs filesystem and if mounts on that are not 'shared', other locations will not behave as expected. In particular access to those other locations will likely result in the `ELOOP` error |