[v4] tmpfs: Add case-insensitive support for tmpfs

[PATCH v4 10/10] docs: tmpfs: Add casefold options

Posted by André Almeida 2 months, 2 weeks ago

Document mounting options for casefold support in tmpfs.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
---
Changes from v3:
- Rewrote note about "this doesn't enable casefold by default" (Krisman)
---
 Documentation/filesystems/tmpfs.rst | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
index 56a26c843dbe..f72fcc0baef3 100644
--- a/Documentation/filesystems/tmpfs.rst
+++ b/Documentation/filesystems/tmpfs.rst
@@ -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 +F attribute in an empty
+directory. Nevertheless, new directories will inherit the attribute. The
+mountpoint itself will 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
-- 
2.46.0

Re: [PATCH v4 10/10] docs: tmpfs: Add casefold options

Posted by Gabriel Krisman Bertazi 2 months, 2 weeks ago

André Almeida <andrealmeid@igalia.com> writes:

> Document mounting options for casefold support in tmpfs.
>
> Signed-off-by: André Almeida <andrealmeid@igalia.com>
> ---
> Changes from v3:
> - Rewrote note about "this doesn't enable casefold by default" (Krisman)
> ---
>  Documentation/filesystems/tmpfs.rst | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
> index 56a26c843dbe..f72fcc0baef3 100644
> --- a/Documentation/filesystems/tmpfs.rst
> +++ b/Documentation/filesystems/tmpfs.rst
> @@ -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 +F attribute in an empty
> +directory. Nevertheless, new directories will inherit the attribute. The

> +mountpoint itself will cannot be made case-insensitive.

s/will//

Other than that:

Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>

> +
> +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

-- 
Gabriel Krisman Bertazi