925c86a19b
Add a new config option that controls building the buffer_head code, and select it from all file systems and stacking drivers that need it. For the block device nodes and alternative iomap based buffered I/O path is provided when buffer_head support is not enabled, and iomap needs a a small tweak to define the IOMAP_F_BUFFER_HEAD flag to 0 to not call into the buffer_head code when it doesn't exist. Otherwise this is just Kconfig and ifdef changes. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20230801172201.1923299-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
5.0 KiB
SPDX-License-Identifier: GPL-2.0-only
config FAT_FS tristate select BUFFER_HEAD select NLS select LEGACY_DIRECT_IO help If you want to use one of the FAT-based file systems (the MS-DOS and VFAT (Windows 95) file systems), then you must say Y or M here to include FAT support. You will then be able to mount partitions or diskettes with FAT-based file systems and transparently access the files on them, i.e. MSDOS files will look and behave just like all other Unix files.
This FAT support is not a file system in itself, it only provides
the foundation for the other file systems. You will have to say Y or
M to at least one of "MSDOS fs support" or "VFAT fs support" in
order to make use of it.
Another way to read and write MSDOS floppies and hard drive
partitions from within Linux (but not transparently) is with the
mtools ("man mtools") program suite. You don't need to say Y here in
order to do that.
If you need to move large files on floppies between a DOS and a
Linux box, say Y here, mount the floppy under Linux with an MSDOS
file system and use GNU tar's M option. GNU tar is a program
available for Unix and DOS ("man tar" or "info tar").
The FAT support will enlarge your kernel by about 37 KB. If unsure,
say Y.
To compile this as a module, choose M here: the module will be called
fat. Note that if you compile the FAT support as a module, you
cannot compile any of the FAT-based file systems into the kernel
-- they will have to be modules as well.
config MSDOS_FS tristate "MSDOS fs support" select FAT_FS help This allows you to mount MSDOS partitions of your hard drive (unless they are compressed; to access compressed MSDOS partitions under Linux, you can either use the DOS emulator DOSEMU, described in the DOSEMU-HOWTO, available from https://www.tldp.org/docs.html#howto, or try dmsdosfs in ftp://ibiblio.org/pub/Linux/system/filesystems/dosfs/. If you intend to use dosemu with a non-compressed MSDOS partition, say Y here) and MSDOS floppies. This means that file access becomes transparent, i.e. the MSDOS files look and behave just like all other Unix files.
If you have Windows 95 or Windows NT installed on your MSDOS
partitions, you should use the VFAT file system (say Y to "VFAT fs
support" below), or you will not be able to see the long filenames
generated by Windows 95 / Windows NT.
This option will enlarge your kernel by about 7 KB. If unsure,
answer Y. This will only work if you said Y to "DOS FAT fs support"
as well. To compile this as a module, choose M here: the module will
be called msdos.
config VFAT_FS tristate "VFAT (Windows-95) fs support" select FAT_FS help This option provides support for normal Windows file systems with long filenames. That includes non-compressed FAT-based file systems used by Windows 95, Windows 98, Windows NT 4.0, and the Unix programs from the mtools package.
The VFAT support enlarges your kernel by about 10 KB and it only
works if you said Y to the "DOS FAT fs support" above. Please read
the file <file:Documentation/filesystems/vfat.rst> for details. If
unsure, say Y.
To compile this as a module, choose M here: the module will be called
vfat.
config FAT_DEFAULT_CODEPAGE int "Default codepage for FAT" depends on FAT_FS default 437 help This option should be set to the codepage of your FAT filesystems. It can be overridden with the "codepage" mount option. See file:Documentation/filesystems/vfat.rst for more information.
config FAT_DEFAULT_IOCHARSET string "Default iocharset for FAT" depends on VFAT_FS default "iso8859-1" help Set this to the default input/output character set you'd like FAT to use. It should probably match the character set that most of your FAT filesystems use, and can be overridden with the "iocharset" mount option for FAT filesystems. Note that "utf8" is not recommended for FAT filesystems. If unsure, you shouldn't set "utf8" here - select the next option instead if you would like to use UTF-8 encoded file names by default. See file:Documentation/filesystems/vfat.rst for more information.
Enable any character sets you need in File Systems/Native Language
Support.
config FAT_DEFAULT_UTF8 bool "Enable FAT UTF-8 option by default" depends on VFAT_FS default n help Set this if you would like to have "utf8" mount option set by default when mounting FAT filesystems.
Even if you say Y here can always disable UTF-8 for
particular mount by adding "utf8=0" to mount options.
Say Y if you use UTF-8 encoding for file names, N otherwise.
See <file:Documentation/filesystems/vfat.rst> for more information.
config FAT_KUNIT_TEST tristate "Unit Tests for FAT filesystems" if !KUNIT_ALL_TESTS depends on KUNIT && FAT_FS default KUNIT_ALL_TESTS help This builds the FAT KUnit tests
For more information on KUnit and unit tests in general, please refer
to the KUnit documentation in Documentation/dev-tools/kunit
If unsure, say N