[PATCH] Updating the documentation of struct file_system_type

[PATCH] Updating the documentation of struct file_system_type

[info]

From: Joris Gutjahr <joris.gutjahr@protonmail.com>

In the documentation of struct file_system_type,
using the definition of the struct of the kernel v5.10-rc6.

Signed-off-by: Joris Gutjahr <joris.gutjahr@protonmail.com>
---
 Documentation/filesystems/vfs.rst | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
index ca52c82e5bb5..364ef3dcb649 100644
--- a/Documentation/filesystems/vfs.rst
+++ b/Documentation/filesystems/vfs.rst
@@ -107,22 +107,30 @@ file /proc/filesystems.
 struct file_system_type
 -----------------------
 
-This describes the filesystem.  As of kernel 2.6.39, the following
-members are defined:
+This describes the filesystem.  As of kernel v5.10, the following
+members are defined: (compare: include/linux/fs.h)
 
 .. code-block:: c
 
-	struct file_system_operations {
+	struct file_system_type {
 		const char *name;
 		int fs_flags;
+        int (*init_fs_context)(struct fs_context*);
+        const struct fs_parameter_spec *parameters;
 		struct dentry *(*mount) (struct file_system_type *, int,
 					 const char *, void *);
 		void (*kill_sb) (struct super_block *);
 		struct module *owner;
 		struct file_system_type * next;
-		struct list_head fs_supers;
+		struct hlist_head fs_supers;
 		struct lock_class_key s_lock_key;
 		struct lock_class_key s_umount_key;
+        struct lock_class_key s_vfs_rename_key;
+        struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
+
+        struct lock_class_key i_lock_key;
+        struct lock_class_key i_mutex_key;
+        struct lock_class_key i_mutex_dir_key;
 	};
 
 ``name``
@@ -132,6 +140,12 @@ members are defined:
 ``fs_flags``
 	various flags (i.e. FS_REQUIRES_DEV, FS_NO_DCACHE, etc.)
 
+``init_fs_context``
+    TODO
+
+``fs_parameter_spec``
+    TODO
+
 ``mount``
 	the method to call when a new instance of this filesystem should
 	be mounted
@@ -148,7 +162,11 @@ members are defined:
 ``next``
 	for internal VFS use: you should initialize this to NULL
 
-  s_lock_key, s_umount_key: lockdep-specific
+``fs_supers``
+    TODO
+
+
+  s_lock_key, s_umount_key, s_vfs_rename_key, s_writers_key, i_lock_key, i_mutex_key, i_mutex_dir_key: lockdep-specific
 
 The mount() method has the following arguments:
 
-- 
2.17.1

Re: [PATCH] Updating the documentation of struct file_system_type

[Jonathan Corbet]

On Tue,  1 Dec 2020 22:05:51 +0100
info@democraticnet.de wrote:

> From: Joris Gutjahr <joris.gutjahr@protonmail.com>
> 
> In the documentation of struct file_system_type,
> using the definition of the struct of the kernel v5.10-rc6.
> 
> Signed-off-by: Joris Gutjahr <joris.gutjahr@protonmail.com>

So I applaud any effort to update this file, but I have a couple of
requests.  First is that any patch like this needs to be run past the
filesystem folks; I've added Al and the fsdevel list to CC as a starting
point.

>  Documentation/filesystems/vfs.rst | 28 +++++++++++++++++++++++-----
>  1 file changed, 23 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
> index ca52c82e5bb5..364ef3dcb649 100644
> --- a/Documentation/filesystems/vfs.rst
> +++ b/Documentation/filesystems/vfs.rst
> @@ -107,22 +107,30 @@ file /proc/filesystems.
>  struct file_system_type
>  -----------------------
>  
> -This describes the filesystem.  As of kernel 2.6.39, the following
> -members are defined:
> +This describes the filesystem.  As of kernel v5.10, the following
> +members are defined: (compare: include/linux/fs.h)
>  
>  .. code-block:: c
>  
> -	struct file_system_operations {
> +	struct file_system_type {
>  		const char *name;
>  		int fs_flags;
> +        int (*init_fs_context)(struct fs_context*);
> +        const struct fs_parameter_spec *parameters;
>  		struct dentry *(*mount) (struct file_system_type *, int,
>  					 const char *, void *);
>  		void (*kill_sb) (struct super_block *);
>  		struct module *owner;
>  		struct file_system_type * next;
> -		struct list_head fs_supers;
> +		struct hlist_head fs_supers;
>  		struct lock_class_key s_lock_key;
>  		struct lock_class_key s_umount_key;
> +        struct lock_class_key s_vfs_rename_key;
> +        struct lock_class_key s_writers_key[SB_FREEZE_LEVELS];
> +
> +        struct lock_class_key i_lock_key;
> +        struct lock_class_key i_mutex_key;
> +        struct lock_class_key i_mutex_dir_key;
>  	};
>  
>  ``name``
> @@ -132,6 +140,12 @@ members are defined:
>  ``fs_flags``
>  	various flags (i.e. FS_REQUIRES_DEV, FS_NO_DCACHE, etc.)
>  
> +``init_fs_context``
> +    TODO
> +
> +``fs_parameter_spec``
> +    TODO

These are ... not particularly helpful.  If we're going to update the
documentation for this structure, we should actually update the
documentation, methinks.

>  ``mount``
>  	the method to call when a new instance of this filesystem should
>  	be mounted
> @@ -148,7 +162,11 @@ members are defined:
>  ``next``
>  	for internal VFS use: you should initialize this to NULL
>  
> -  s_lock_key, s_umount_key: lockdep-specific
> +``fs_supers``
> +    TODO
> +
> +
> +  s_lock_key, s_umount_key, s_vfs_rename_key, s_writers_key, i_lock_key, i_mutex_key, i_mutex_dir_key: lockdep-specific

You should maintain the RST description-list formatting here.

>  The mount() method has the following arguments:

Thanks,

jon