Re: [RFC PATCH 4/4] docs: tmpfs: Add casefold options
From: Gabriel Krisman Bertazi <hidden>
Date: 2021-03-23 22:23:04
Also in:
linux-fsdevel, lkml
André Almeida [off-list ref] writes:
quoted hunk
Document mounting options to enable casefold support in tmpfs. Signed-off-by: André Almeida <redacted> --- Documentation/filesystems/tmpfs.rst | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst index 0408c245785e..84c87c309bd7 100644 --- a/Documentation/filesystems/tmpfs.rst +++ b/Documentation/filesystems/tmpfs.rst@@ -170,6 +170,32 @@ 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-insesitive lookups support: + +========= ============================================================== +casefold Enable casefold support at this mount point using the given + argument as enconding. Currently only utf8 encondings are supported. +cf_strict Enable strict casefolding at this mouting point (disabled by + default). This means that invalid strings should be reject by the + file system.
strict mode refers to the encoding, not exactly casefold. Maybe we could have a parameter encoding_flags that accepts the flag 'strict'. This would make it closer to the ext4 interface. Alternatively, call this option strict_encoding.
+========= ==============================================================
+
+Note that this option doesn't enable casefold by default, one needs to set
+casefold flag per directory, setting the +F attribute in an empty directory. New
+directories within a casefolded one will inherit the flag.
+
+Example::
+
+ $ mount -t tmpfs -o casefold=utf8-12.1.0,cf_strict tmpfs /mytmpfs
+ $ cd /mytmpfs
+ $ touch a; touch A
+ $ ls
+ A a
+ $ mkdir dir
+ $ chattr +F dir
+ $ touch dir/a; touch dir/A
+ $ ls dir
+ a
:Author:
Christoph Rohland [off-list ref], 1.12.01-- Gabriel Krisman Bertazi