From: Eric Biggers <ebiggers@xxxxxxxxxx> The 'f' ioctls with numbers 19-26 decimal are currently used for fscrypt (a.k.a. ext4/f2fs/ubifs encryption), and up to 39 decimal is reserved for future fscrypt use, as per the comment in fs/ext4/ext4.h. So the reserved range is 13-27 hex. Document this in ioctl-number.rst. Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> --- Documentation/ioctl/ioctl-number.rst | 1 + 1 file changed, 1 insertion(+) diff --git a/Documentation/ioctl/ioctl-number.rst b/Documentation/ioctl/ioctl-number.rst index bef79cd4c6b4d..4ef86433bd677 100644 --- a/Documentation/ioctl/ioctl-number.rst +++ b/Documentation/ioctl/ioctl-number.rst @@ -233,6 +233,7 @@ Code Seq# Include File Comments 'f' 00-0F fs/ext4/ext4.h conflict! 'f' 00-0F linux/fs.h conflict! 'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict! +'f' 13-27 linux/fscrypt.h 'f' 81-8F linux/fsverity.h 'g' 00-0F linux/usb/gadgetfs.h 'g' 20-2F linux/usb/g_printer.h -- 2.23.0.581.g78d2f28ef7-goog