[Devel] [PATCH rh7 1/2] ve: Introduce ve::devmnt list
Maxim Patlasov
mpatlasov at openvz.org
Wed May 6 15:05:59 PDT 2015
Kirill, see please a couple of inline comments below...
On 04/29/2015 01:29 AM, Kirill Tkhai wrote:
> 1)Porting patch "ve: mount option list" by Maxim Patlasov:
>
> The patch adds new fields to ve_struct: devmnt_list and devmnt_mutex.
>
> devmnt_list is the head of list of ve_devmnt structs. Each host block device
> visible from CT can have no more than one struct ve_devmnt linked in
> ve->devmnt_list. If ve_devmnt is present, it can be found by 'dev' field.
> Each ve_devmnt struct may bear two strings: hidden and allowed options.
>
> hidden_options will be automatically added to CT-user-supplied mount options
> after checking allowed_options. Only options listed in allowed_options are
> allowed.
>
> devmnt_mutex is to protect operations on the list of ve_devmnt structs.
>
> 2)Porting patch "vecalls: VE_CONFIGURE_MOUNT_OPTIONS" by Maxim Patlasov.
>
> Reworking the interface using cgroups. Each CT now has a file:
>
> [ve_cgroup_mnt_pnt]/[CTID]/ve.mount_opts
>
> for configuring permittions for a block device. Below is permittions line
> example:
>
> "0 xxx;1 balloon_ino=12,pfcache_csum,pfcache=/vz/pfcache;2 barrier=1"
>
> Here, xxx is st_rdev of device, '1' starts comma-separated list of
> hidden options, and '2' is allowed ones.
>
> Signed-off-by: Kirill Tkhai <ktkhai at odin.com>
> ---
> include/linux/ve.h | 11 ++++
> kernel/ve/ve.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 159 insertions(+)
>
> diff --git a/include/linux/ve.h b/include/linux/ve.h
> index 61f31fd..98dd244 100644
> --- a/include/linux/ve.h
> +++ b/include/linux/ve.h
> @@ -123,6 +123,9 @@ struct ve_struct {
> struct net *ve_netns;
> struct mutex sync_mutex;
>
> + struct list_head devmnt_list;
> + struct mutex devmnt_mutex;
> +
> struct kmapset_key ve_sysfs_perms;
> struct list_head ve_cgroup_head;
> #if IS_ENABLED(CONFIG_DEVTMPFS)
> @@ -130,6 +133,14 @@ struct ve_struct {
> #endif
> };
>
> +struct ve_devmnt {
> + struct list_head link;
> +
> + dev_t dev;
> + char *allowed_options;
> + char *hidden_options; /* balloon_ino, etc. */
> +};
> +
> #define VE_MEMINFO_DEFAULT 1 /* default behaviour */
> #define VE_MEMINFO_SYSTEM 0 /* disable meminfo virtualization */
>
> diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
> index ee2435c..e963b56 100644
> --- a/kernel/ve/ve.c
> +++ b/kernel/ve/ve.c
> @@ -749,6 +749,8 @@ static struct cgroup_subsys_state *ve_create(struct cgroup *cg)
> INIT_LIST_HEAD(&ve->devices);
> INIT_LIST_HEAD(&ve->ve_cgroup_head);
> INIT_LIST_HEAD(&ve->ve_list);
> + INIT_LIST_HEAD(&ve->devmnt_list);
> + mutex_init(&ve->devmnt_mutex);
> kmapset_init_key(&ve->ve_sysfs_perms);
>
> return &ve->css;
> @@ -782,11 +784,33 @@ static void ve_offline(struct cgroup *cg)
> }
> }
>
> +static void ve_devmnt_free(struct ve_devmnt *devmnt)
> +{
> + if (!devmnt)
> + return;
> +
> + kfree(devmnt->allowed_options);
> + kfree(devmnt->hidden_options);
> + kfree(devmnt);
> +}
> +
> +static void free_ve_devmnts(struct ve_struct *ve)
> +{
> + while (!list_empty(&ve->devmnt_list)) {
> + struct ve_devmnt *devmnt;
> +
> + devmnt = list_first_entry(&ve->devmnt_list, struct ve_devmnt, link);
> + list_del(&devmnt->link);
> + ve_devmnt_free(devmnt);
> + }
> +}
> +
> static void ve_destroy(struct cgroup *cg)
> {
> struct ve_struct *ve = cgroup_ve(cg);
>
> kmapset_unlink(&ve->ve_sysfs_perms, &ve_sysfs_perms);
> + free_ve_devmnts(ve);
>
> ve_log_destroy(ve);
> kfree(ve->binfmt_misc);
> @@ -934,6 +958,125 @@ static int ve_legacy_veid_read(struct cgroup *cg, struct cftype *cft,
> return seq_printf(m, "%u\n", cgroup_ve(cg)->veid);
> }
>
> +/*
> + * 'data' for VE_CONFIGURE_MOUNT_OPTIONS is a zero-terminated string
> + * consisting of substrings separated by MNTOPT_DELIM.
> + */
> +#define MNTOPT_DELIM ';'
> +
> +/*
> + * Each substring has the form of "<type> <comma-separated-list-of-options>"
> + * where types are:
> + */
> +enum {
> + MNTOPT_DEVICE = 0,
> + MNTOPT_HIDDEN = 1,
> + MNTOPT_ALLOWED = 2,
> +};
> +
> +/*
> + * 'ptr' points to the first character of buffer to parse
> + * 'endp' points to the last character of buffer to parse
> + */
> +static int ve_parse_mount_options(const char *ptr, const char *endp,
> + struct ve_devmnt *devmnt)
> +{
> + while (*ptr) {
> + const char *delim = strchr(ptr, MNTOPT_DELIM) ? : endp;
> + char *space = strchr(ptr, ' ');
> + int type;
> + char *options, c;
> + int options_size = delim - space;
> + char **opts_pp = NULL; /* where to store 'options' */
> +
> + if (delim == ptr || !space || options_size <= 1)
> + return -EINVAL;
> +
> + if (sscanf(ptr, "%d%c", &type, &c) != 2 || c != ' ')
> + return -EINVAL;
> +
> + if (type == MNTOPT_DEVICE) {
> + unsigned int dev;
> + if (devmnt->dev)
> + return -EINVAL; /* Already set */
> + if (sscanf(space + 1, "%u%c", &dev, &c) != 2 ||
> + c != ';')
> + return -EINVAL;
> + devmnt->dev = new_decode_dev(dev);
I think major:minor would be better (human readable) string
representation of devmnt->dev than unsigned integer st_rdev.
> + goto next;
> + }
> +
> + options = kmalloc(options_size, GFP_KERNEL);
> + if (!options)
> + return -ENOMEM;
> +
> + strncpy(options, space + 1, options_size - 1);
> + options[options_size - 1] = 0;
> +
> + switch (type) {
> + case MNTOPT_ALLOWED:
> + opts_pp = &devmnt->allowed_options;
> + break;
> + case MNTOPT_HIDDEN:
> + opts_pp = &devmnt->hidden_options;
> + break;
> + };
> +
> + /* wrong type or already set */
> + if (!opts_pp || *opts_pp) {
> + kfree(options);
> + return -EINVAL;
> + }
> +
> + *opts_pp = options;
> +next:
> + if (!*delim)
> + break;
> +
> + ptr = delim + 1;
> + }
> +
> + if (!devmnt->dev)
> + return -EINVAL;
> + return 0;
> +}
> +
> +static int ve_mount_opts_write(struct cgroup *cg, struct cftype *cft,
> + const char *buffer)
> +{
> + struct ve_struct *ve = cgroup_ve(cg);
> + struct ve_devmnt *devmnt, *old;
> + int size, err;
> +
> + size = strlen(buffer);
> + if (size <= 1)
> + return -EINVAL;
> +
> + devmnt = kzalloc(sizeof(*devmnt), GFP_KERNEL);
> + if (!devmnt)
> + return -ENOMEM;
> +
> + err = ve_parse_mount_options(buffer, buffer + size, devmnt);
> + if (err) {
> + ve_devmnt_free(devmnt);
> + return err;
> + }
> +
> + mutex_lock(&ve->devmnt_mutex);
> + list_for_each_entry(old, &ve->devmnt_list, link) {
> + /* Delete old devmnt */
> + if (old->dev == devmnt->dev) {
> + list_del(&old->link);
> + ve_devmnt_free(old);
> + break;
> + }
> + }
> + list_add(&devmnt->link, &ve->devmnt_list);
> + mutex_unlock(&ve->devmnt_mutex);
> +
> + return 0;
> +}
> +
> static struct cftype ve_cftypes[] = {
> {
> .name = "state",
> @@ -946,6 +1089,11 @@ static struct cftype ve_cftypes[] = {
> .flags = CFTYPE_NOT_ON_ROOT,
> .read_seq_string = ve_legacy_veid_read,
> },
> + {
> + .name = "mount_opts",
> + .flags = CFTYPE_NOT_ON_ROOT,
> + .write_string = ve_mount_opts_write,
> + },
Why no read method?
Thanks,
Maxim
More information about the Devel
mailing list