docs: tmpfs: Add casefold options

Document mounting options for casefold support in tmpfs.

Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241021-tonyk-tmpfs-v8-9-f443d5814194@igalia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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André Almeida 2024-10-21 13:37:25 -03:00 committed by Christian Brauner
parent 5132f08bd3
commit a713f830c9
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@ -241,6 +241,28 @@ So 'mount -t tmpfs -o size=10G,nr_inodes=10k,mode=700 tmpfs /mytmpfs'
will give you tmpfs instance on /mytmpfs which can allocate 10GB
RAM/SWAP in 10240 inodes and it is only accessible by root.
tmpfs has the following mounting options for case-insensitive lookup support:
================= ==============================================================
casefold Enable casefold support at this mount point using the given
argument as the encoding standard. Currently only UTF-8
encodings are supported. If no argument is used, it will load
the latest UTF-8 encoding available.
strict_encoding Enable strict encoding at this mount point (disabled by
default). In this mode, the filesystem refuses to create file
and directory with names containing invalid UTF-8 characters.
================= ==============================================================
This option doesn't render the entire filesystem case-insensitive. One needs to
still set the casefold flag per directory, by flipping the +F attribute in an
empty directory. Nevertheless, new directories will inherit the attribute. The
mountpoint itself cannot be made case-insensitive.
Example::
$ mount -t tmpfs -o casefold=utf8-12.1.0,strict_encoding fs_name /mytmpfs
$ mount -t tmpfs -o casefold fs_name /mytmpfs
:Author:
Christoph Rohland <cr@sap.com>, 1.12.01
@ -250,3 +272,5 @@ RAM/SWAP in 10240 inodes and it is only accessible by root.
KOSAKI Motohiro, 16 Mar 2010
:Updated:
Chris Down, 13 July 2020
:Updated:
André Almeida, 23 Aug 2024