Filesystem-Independent Mount Options (cont.) and Filesystem-Specific Options

using the syntax id-type:id-mount:id-host:id-range. Specifying u as the id-type prefix creates a UID-mapping, g creates a GID-mapping and omitting id-type or specifying b creates both a UID- and GID-mapping. The id-mount parameter indicates the starting ID in the new mount. The id-host parameter indicates the starting ID in the filesystem. The id-range parameter indicates how many IDs are to be mapped. It is possible to specify multiple ID-mappings. The individual ID-mappings must be separated by spaces. For example, the ID-mapping X-mount.idmap=u:1000:0:1 g:1001:1:2 5000:1000:2 creates an idmapped mount where UID 0 is mapped to UID 1000, GID 1 is mapped to GUID 1001, GID 2 is mapped to GID 1002, UID and GID 1000 are mapped to 5000, and UID and GID 1001 are mapped to 5001 in the mount. When an ID-mapping is specified directly a new user namespace will be allocated with the requested ID-mapping. The newly created user namespace will be attached to the mount. • A user can specify a user namespace file. The user namespace will then be attached to the mount and the ID-mapping of the user namespace will become the ID-mapping of the mount. For example, X-mount.idmap=/proc/PID/ns/user will attach the user namespace of the process PID to the mount. nosymfollow Do not follow symlinks when resolving paths. Symlinks can still be created, and readlink(1), readlink(2), realpath(1), and realpath(3) all still work properly. FILESYSTEM-SPECIFIC MOUNT OPTIONS This section lists options that are specific to particular filesystems. Where possible, you should first consult filesystem-specific manual pages for details. Some of those pages are listed in the following table. ┌──────────────────┬───────────────┐ │ │ │ │ Filesystem(s) │ Manual page │ ├──────────────────┼───────────────┤ │ │ │ │ btrfs │ btrfs(5) │ ├──────────────────┼───────────────┤ │ │ │ │ cifs │ mount.cifs(8) │ ├──────────────────┼───────────────┤ │ │ │ │ ext2, ext3, ext4 │ ext4(5) │ ├──────────────────┼───────────────┤ │ │ │ │ fuse │ fuse(8) │ ├──────────────────┼───────────────┤ │ │ │ │ nfs │ nfs(5) │ ├──────────────────┼───────────────┤ │ │ │ │ tmpfs │ tmpfs(5) │ ├──────────────────┼───────────────┤ │ │ │ │ xfs │ xfs(5) │ └──────────────────┴───────────────┘ Note that some of the pages listed above might be available only after you install the respective userland tools. The following options apply only to certain filesystems. We sort them by filesystem. All options follow the -o flag. What options are supported depends a bit on the running kernel. Further information may be available in filesystem-specific files in the kernel source subdirectory Documentation/filesystems. Mount options for adfs uid=value and gid=value Set the owner and group of the files in the filesystem (default: uid=gid=0). ownmask=value and othmask=value Set the permission mask for ADFS 'owner' permissions and 'other' permissions, respectively (default: 0700 and

The document continues discussing the `X-mount.idmap` option, detailing how to specify ID mappings either directly or via a user namespace file. It then introduces the `nosymfollow` option to prevent symlink following. The document transitions to filesystem-specific mount options, providing a table of filesystems and their respective manual pages. It emphasizes that available options depend on the kernel and encourages consulting filesystem-specific documentation. It begins with adfs options, including `uid`, `gid`, `ownmask`, and `othmask`.