ich777/linux_media
1
0
Fork 0
mirror of https://github.com/tbsdtv/linux_media.git synced 2025-07-23 04:33:26 +02:00
Code Issues Packages Projects Releases Wiki Activity

vfs: Implement a filesystem superblock creation/configuration context

Browse Source 
[AV - unfuck kern_mount_data(); we want non-NULL ->mnt_ns on long-living
mounts]
[AV - reordering fs/namespace.c is badly overdue, but let's keep it
separate from that series]
[AV - drop simple_pin_fs() change]
[AV - clean vfs_kern_mount() failure exits up]

Implement a filesystem context concept to be used during superblock
creation for mount and superblock reconfiguration for remount.

The mounting procedure then becomes:

 (1) Allocate new fs_context context.

 (2) Configure the context.

 (3) Create superblock.

 (4) Query the superblock.

 (5) Create a mount for the superblock.

 (6) Destroy the context.

Rather than calling fs_type->mount(), an fs_context struct is created and
fs_type->init_fs_context() is called to set it up.  Pointers exist for the
filesystem and LSM to hang their private data off.

A set of operations has to be set by ->init_fs_context() to provide
freeing, duplication, option parsing, binary data parsing, validation,
mounting and superblock filling.

Legacy filesystems are supported by the provision of a set of legacy
fs_context operations that build up a list of mount options and then invoke
fs_type->mount() from within the fs_context ->get_tree() operation.  This
allows all filesystems to be accessed using fs_context.

It should be noted that, whilst this patch adds a lot of lines of code,
there is quite a bit of duplication with existing code that can be
eliminated should all filesystems be converted over.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
David Howells
2018-11-01 23:07:25 +00:00
committed by Al Viro
parent 846e566218
commit 3e1aeb00e6
5 changed files with 319 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
fs/filesystems.c
View File

@@ -16,6 +16,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/fs_parser.h>
/*
* Handling of filesystem drivers list.
@@ -73,6 +74,9 @@ int register_filesystem(struct file_system_type * fs)
int res = 0;
struct file_system_type ** p;
if (fs->parameters && !fs_validate_description(fs->parameters))
return -EINVAL;
BUG_ON(strchr(fs->name, '.'));
if (fs->next)
return -EBUSY;