linux/fs/sysv/file.c
Christian Brauner 549c729771
fs: make helpers idmap mount aware
Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:20 +01:00

60 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/sysv/file.c
*
* minix/file.c
* Copyright (C) 1991, 1992 Linus Torvalds
*
* coh/file.c
* Copyright (C) 1993 Pascal Haible, Bruno Haible
*
* sysv/file.c
* Copyright (C) 1993 Bruno Haible
*
* SystemV/Coherent regular file handling primitives
*/
#include "sysv.h"
/*
* We have mostly NULLs here: the current defaults are OK for
* the coh filesystem.
*/
const struct file_operations sysv_file_operations = {
.llseek = generic_file_llseek,
.read_iter = generic_file_read_iter,
.write_iter = generic_file_write_iter,
.mmap = generic_file_mmap,
.fsync = generic_file_fsync,
.splice_read = generic_file_splice_read,
};
static int sysv_setattr(struct user_namespace *mnt_userns,
struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
int error;
error = setattr_prepare(&init_user_ns, dentry, attr);
if (error)
return error;
if ((attr->ia_valid & ATTR_SIZE) &&
attr->ia_size != i_size_read(inode)) {
error = inode_newsize_ok(inode, attr->ia_size);
if (error)
return error;
truncate_setsize(inode, attr->ia_size);
sysv_truncate(inode);
}
setattr_copy(&init_user_ns, inode, attr);
mark_inode_dirty(inode);
return 0;
}
const struct inode_operations sysv_file_inode_operations = {
.setattr = sysv_setattr,
.getattr = sysv_getattr,
};