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author | David Sterba <dsterba@suse.com> | 2023-12-06 15:00:49 +0100 |
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committer | David Sterba <dsterba@suse.com> | 2023-12-06 17:44:28 +0100 |
commit | 478a295b006df4078809c14b20ffd9b01432c96e (patch) | |
tree | 054960ad5fefadfb56b076e69fae0ed5a47ae0d7 /Documentation | |
parent | f9ebee683871324c9a51c79009c9061ea252c858 (diff) | |
download | btrfs-progs-478a295b006df4078809c14b20ffd9b01432c96e.tar.gz |
btrfs-progs: docs: document label ioctls
[ci skip]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/btrfs-ioctl.rst | 57 |
1 files changed, 51 insertions, 6 deletions
diff --git a/Documentation/btrfs-ioctl.rst b/Documentation/btrfs-ioctl.rst index 49da01ac..0dac021d 100644 --- a/Documentation/btrfs-ioctl.rst +++ b/Documentation/btrfs-ioctl.rst @@ -177,6 +177,8 @@ DATA STRUCTURES AND DEFINITIONS __u8 reserved[944]; /* pad to 1k */ }; +.. _constants-table: + .. list-table:: :header-rows: 1 @@ -192,6 +194,8 @@ DATA STRUCTURES AND DEFINITIONS - 4087 * - BTRFS_VOL_NAME_MAX - 255 + * - BTRFS_LABEL_SIZE + - 256 OVERVIEW -------- @@ -372,12 +376,12 @@ LIST OF IOCTLS * - BTRFS_IOC_QUOTA_RESCAN_WAIT - - - * - BTRFS_IOC_GET_FSLABEL - - - - - * - BTRFS_IOC_SET_FSLABEL - - - - + * - :ref:`BTRFS_IOC_GET_FSLABEL<BTRFS_IOC_GET_FSLABEL>` + - read filesystem label + - char buffer[BTRFS_LABEL_SIZE] + * - :ref:`BTRFS_IOC_SET_FSLABEL<BTRFS_IOC_SET_FSLABEL>` + - set the filesystem label + - char buffer[BTRFS_LABEL_SIZE] * - BTRFS_IOC_GET_DEV_STATS - - @@ -710,6 +714,47 @@ Change the flags of a subvolume. * - ioctl args - uint64_t, either 0 or `BTRFS_SUBVOL_RDONLY` +.. _BTRFS_IOC_GET_FSLABEL: + +BTRFS_IOC_GET_FSLABEL +~~~~~~~~~~~~~~~~~~~~~ + +Read the label of the filesystem into a given buffer. Alternatively it +can be read from :file:`/sys/fs/btrfs/FSID/label` though it requires to +know the FSID of the filesystem. + +.. list-table:: + :header-rows: 1 + + * - Field + - Description + * - ioctl fd + - file descriptor of any file/directory in the filesystem + * - ioctl args + - char buffer[:ref:`BTRFS_LABEL_SIZE<constants-table>`] + +.. _BTRFS_IOC_SET_FSLABEL: + +BTRFS_IOC_SET_FSLABEL +~~~~~~~~~~~~~~~~~~~~~ + +Set the label of filesystem from given buffer. The maximum length also accounts +for terminating NUL character. Alternatively it can be also set by writing to +:file:`/sys/fs/btrfs/FSID/label` though it requires to know the FSID of the +filesystem (and an explicit commit before the change is permanent). + +Required permissions: CAP_SYS_ADMIN + +.. list-table:: + :header-rows: 1 + + * - Field + - Description + * - ioctl fd + - file descriptor of any file/directory in the filesystem + * - ioctl args + - char buffer[:ref:`BTRFS_LABEL_SIZE<constants-table>`] + .. _BTRFS_IOC_FS_INFO: BTRFS_IOC_FS_INFO |