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Diffstat (limited to 'Kconfig')
-rw-r--r-- | Kconfig | 93 |
1 files changed, 93 insertions, 0 deletions
@@ -0,0 +1,93 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Loop device driver configuration +# + +config BLK_DEV_LOOP + tristate "Loopback device support" + ---help--- + Saying Y here will allow you to use a regular file as a block + device; you can then create a file system on that block device and + mount it just as you would mount other block devices such as hard + drive partitions, CD-ROM drives or floppy drives. The loop devices + are block special device files with major number 7 and typically + called /dev/loop0, /dev/loop1 etc. + + This is useful if you want to check an ISO 9660 file system before + burning the CD, or if you want to use floppy images without first + writing them to floppy. Furthermore, some Linux distributions avoid + the need for a dedicated Linux partition by keeping their complete + root file system inside a DOS FAT file using this loop device + driver. + + To use the loop device, you need the losetup utility, found in the + util-linux package, see + <https://www.kernel.org/pub/linux/utils/util-linux/>. + + The loop device driver can also be used to "hide" a file system in + a disk partition, floppy, or regular file, either using encryption + (scrambling the data) or steganography (hiding the data in the low + bits of, say, a sound file). This is also safe if the file resides + on a remote file server. + + There are several ways of encrypting disks. Some of these require + kernel patches. The vanilla kernel offers the cryptoloop option + and a Device Mapper target (which is superior, as it supports all + file systems). If you want to use the cryptoloop, say Y to both + LOOP and CRYPTOLOOP, and make sure you have a recent (version 2.12 + or later) version of util-linux. Additionally, be aware that + the cryptoloop is not safe for storing journaled filesystems. + + Note that this loop device has nothing to do with the loopback + device used for network connections from the machine to itself. + + To compile this driver as a module, choose M here: the + module will be called loop. + + Most users will answer N here. + +config BLK_DEV_LOOP_MIN_COUNT + int "Number of loop devices to pre-create at init time" + depends on BLK_DEV_LOOP + default 8 + help + Static number of loop devices to be unconditionally pre-created + at init time. + + This default value can be overwritten on the kernel command + line or with module-parameter loop.max_loop. + + The historic default is 8. If a late 2011 version of losetup(8) + is used, it can be set to 0, since needed loop devices can be + dynamically allocated with the /dev/loop-control interface. + +config BLK_DEV_CRYPTOLOOP + tristate "Cryptoloop Support" + select CRYPTO + select CRYPTO_CBC + depends on BLK_DEV_LOOP + ---help--- + Say Y here if you want to be able to use the ciphers that are + provided by the CryptoAPI as loop transformation. This might be + used as hard disk encryption. + + WARNING: This device is not safe for journaled file systems like + ext3 or Reiserfs. Please use the Device Mapper crypto module + instead, which can be configured to be on-disk compatible with the + cryptoloop device. + +config BLK_DEV_LOOP_FILE_FMT_RAW + tristate "Loop device binary file format support" + depends on BLK_DEV_LOOP + ---help--- + Say Y or M here if you want to enable the binary (RAW) file format + support of the loop device module. + +config BLK_DEV_LOOP_FILE_FMT_QCOW + tristate "Loop device QCOW file format support" + depends on BLK_DEV_LOOP + select ZLIB_INFLATE + select ZLIB_DEFLATE + ---help--- + Say Y or M here if you want to enable the QEMU's copy on write (QCOW) + file format support of the loop device module. |