linux/fs/coda/inode.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

332 lines
7.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Super block/filesystem wide operations
*
* Copyright (C) 1996 Peter J. Braam <braam@maths.ox.ac.uk> and
* Michael Callahan <callahan@maths.ox.ac.uk>
*
* Rewritten for Linux 2.1. Peter Braam <braam@cs.cmu.edu>
* Copyright (C) Carnegie Mellon University
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/file.h>
#include <linux/vfs.h>
#include <linux/slab.h>
#include <linux/pid_namespace.h>
#include <linux/uaccess.h>
#include <linux/fs.h>
#include <linux/vmalloc.h>
#include <linux/coda.h>
#include "coda_psdev.h"
#include "coda_linux.h"
#include "coda_cache.h"
#include "coda_int.h"
/* VFS super_block ops */
static void coda_evict_inode(struct inode *);
static void coda_put_super(struct super_block *);
static int coda_statfs(struct dentry *dentry, struct kstatfs *buf);
static struct kmem_cache * coda_inode_cachep;
static struct inode *coda_alloc_inode(struct super_block *sb)
{
struct coda_inode_info *ei;
ei = kmem_cache_alloc(coda_inode_cachep, GFP_KERNEL);
if (!ei)
return NULL;
memset(&ei->c_fid, 0, sizeof(struct CodaFid));
ei->c_flags = 0;
ei->c_uid = GLOBAL_ROOT_UID;
ei->c_cached_perm = 0;
spin_lock_init(&ei->c_lock);
return &ei->vfs_inode;
}
static void coda_free_inode(struct inode *inode)
{
kmem_cache_free(coda_inode_cachep, ITOC(inode));
}
static void init_once(void *foo)
{
struct coda_inode_info *ei = (struct coda_inode_info *) foo;
inode_init_once(&ei->vfs_inode);
}
int __init coda_init_inodecache(void)
{
coda_inode_cachep = kmem_cache_create("coda_inode_cache",
sizeof(struct coda_inode_info), 0,
SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
SLAB_ACCOUNT, init_once);
if (coda_inode_cachep == NULL)
return -ENOMEM;
return 0;
}
void coda_destroy_inodecache(void)
{
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(coda_inode_cachep);
}
static int coda_remount(struct super_block *sb, int *flags, char *data)
{
sync_filesystem(sb);
*flags |= SB_NOATIME;
return 0;
}
/* exported operations */
static const struct super_operations coda_super_operations =
{
.alloc_inode = coda_alloc_inode,
.free_inode = coda_free_inode,
.evict_inode = coda_evict_inode,
.put_super = coda_put_super,
.statfs = coda_statfs,
.remount_fs = coda_remount,
};
static int get_device_index(struct coda_mount_data *data)
{
struct fd f;
struct inode *inode;
int idx;
if (data == NULL) {
pr_warn("%s: Bad mount data\n", __func__);
return -1;
}
if (data->version != CODA_MOUNT_VERSION) {
pr_warn("%s: Bad mount version\n", __func__);
return -1;
}
f = fdget(data->fd);
if (!f.file)
goto Ebadf;
inode = file_inode(f.file);
if (!S_ISCHR(inode->i_mode) || imajor(inode) != CODA_PSDEV_MAJOR) {
fdput(f);
goto Ebadf;
}
idx = iminor(inode);
fdput(f);
if (idx < 0 || idx >= MAX_CODADEVS) {
pr_warn("%s: Bad minor number\n", __func__);
return -1;
}
return idx;
Ebadf:
pr_warn("%s: Bad file\n", __func__);
return -1;
}
static int coda_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *root = NULL;
struct venus_comm *vc;
struct CodaFid fid;
int error;
int idx;
if (task_active_pid_ns(current) != &init_pid_ns)
return -EINVAL;
idx = get_device_index((struct coda_mount_data *) data);
/* Ignore errors in data, for backward compatibility */
if(idx == -1)
idx = 0;
pr_info("%s: device index: %i\n", __func__, idx);
vc = &coda_comms[idx];
mutex_lock(&vc->vc_mutex);
if (!vc->vc_inuse) {
pr_warn("%s: No pseudo device\n", __func__);
error = -EINVAL;
goto unlock_out;
}
if (vc->vc_sb) {
pr_warn("%s: Device already mounted\n", __func__);
error = -EBUSY;
goto unlock_out;
}
vc->vc_sb = sb;
mutex_unlock(&vc->vc_mutex);
sb->s_fs_info = vc;
sb->s_flags |= SB_NOATIME;
sb->s_blocksize = 4096; /* XXXXX what do we put here?? */
sb->s_blocksize_bits = 12;
sb->s_magic = CODA_SUPER_MAGIC;
sb->s_op = &coda_super_operations;
sb->s_d_op = &coda_dentry_operations;
sb->s_time_gran = 1;
sb->s_time_min = S64_MIN;
sb->s_time_max = S64_MAX;
error = super_setup_bdi(sb);
if (error)
goto error;
/* get root fid from Venus: this needs the root inode */
error = venus_rootfid(sb, &fid);
if ( error ) {
pr_warn("%s: coda_get_rootfid failed with %d\n",
__func__, error);
goto error;
}
pr_info("%s: rootfid is %s\n", __func__, coda_f2s(&fid));
/* make root inode */
root = coda_cnode_make(&fid, sb);
if (IS_ERR(root)) {
error = PTR_ERR(root);
pr_warn("Failure of coda_cnode_make for root: error %d\n",
error);
goto error;
}
pr_info("%s: rootinode is %ld dev %s\n",
__func__, root->i_ino, root->i_sb->s_id);
sb->s_root = d_make_root(root);
if (!sb->s_root) {
error = -EINVAL;
goto error;
}
return 0;
error:
mutex_lock(&vc->vc_mutex);
vc->vc_sb = NULL;
sb->s_fs_info = NULL;
unlock_out:
mutex_unlock(&vc->vc_mutex);
return error;
}
static void coda_put_super(struct super_block *sb)
{
struct venus_comm *vcp = coda_vcp(sb);
mutex_lock(&vcp->vc_mutex);
vcp->vc_sb = NULL;
sb->s_fs_info = NULL;
mutex_unlock(&vcp->vc_mutex);
mutex_destroy(&vcp->vc_mutex);
pr_info("Bye bye.\n");
}
static void coda_evict_inode(struct inode *inode)
{
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
coda_cache_clear_inode(inode);
}
int coda_getattr(struct user_namespace *mnt_userns, const struct path *path,
struct kstat *stat, u32 request_mask, unsigned int flags)
{
int err = coda_revalidate_inode(d_inode(path->dentry));
if (!err)
generic_fillattr(&init_user_ns, d_inode(path->dentry), stat);
return err;
}
int coda_setattr(struct user_namespace *mnt_userns, struct dentry *de,
struct iattr *iattr)
{
struct inode *inode = d_inode(de);
struct coda_vattr vattr;
int error;
memset(&vattr, 0, sizeof(vattr));
inode->i_ctime = current_time(inode);
coda_iattr_to_vattr(iattr, &vattr);
vattr.va_type = C_VNON; /* cannot set type */
/* Venus is responsible for truncating the container-file!!! */
error = venus_setattr(inode->i_sb, coda_i2f(inode), &vattr);
if (!error) {
coda_vattr_to_iattr(inode, &vattr);
coda_cache_clear_inode(inode);
}
return error;
}
const struct inode_operations coda_file_inode_operations = {
.permission = coda_permission,
.getattr = coda_getattr,
.setattr = coda_setattr,
};
static int coda_statfs(struct dentry *dentry, struct kstatfs *buf)
{
int error;
error = venus_statfs(dentry, buf);
if (error) {
/* fake something like AFS does */
buf->f_blocks = 9000000;
buf->f_bfree = 9000000;
buf->f_bavail = 9000000;
buf->f_files = 9000000;
buf->f_ffree = 9000000;
}
/* and fill in the rest */
buf->f_type = CODA_SUPER_MAGIC;
buf->f_bsize = 4096;
buf->f_namelen = CODA_MAXNAMLEN;
return 0;
}
/* init_coda: used by filesystems.c to register coda */
static struct dentry *coda_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_nodev(fs_type, flags, data, coda_fill_super);
}
struct file_system_type coda_fs_type = {
.owner = THIS_MODULE,
.name = "coda",
.mount = coda_mount,
.kill_sb = kill_anon_super,
.fs_flags = FS_BINARY_MOUNTDATA,
};
MODULE_ALIAS_FS("coda");