block/rnbd: client: sysfs interface functions
authorJack Wang <jinpu.wang@cloud.ionos.com>
Mon, 11 May 2020 13:51:24 +0000 (15:51 +0200)
committerJason Gunthorpe <jgg@mellanox.com>
Sun, 17 May 2020 21:57:16 +0000 (18:57 -0300)
This is the sysfs interface to rnbd block devices on client side:

  /sys/class/rnbd-client/ctl/
    |- map_device
    |  *** maps remote device
    |
    |- devices/
       *** all mapped devices

  /sys/block/rnbd<N>/rnbd/
    |- unmap_device
    |  *** unmaps device
    |
    |- state
    |  *** device state
    |
    |- session
    |  *** session name
    |
    |- mapping_path
       *** path of the dev that was mapped on server

Link: https://lore.kernel.org/r/20200511135131.27580-19-danil.kipnis@cloud.ionos.com
Signed-off-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
drivers/block/rnbd/rnbd-clt-sysfs.c [new file with mode: 0644]

diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c
new file mode 100644 (file)
index 0000000..a4508fc
--- /dev/null
@@ -0,0 +1,636 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * RDMA Network Block Driver
+ *
+ * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
+ * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
+ * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
+ */
+
+#undef pr_fmt
+#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
+
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/parser.h>
+#include <linux/module.h>
+#include <linux/in6.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/device.h>
+#include <rdma/ib.h>
+#include <rdma/rdma_cm.h>
+
+#include "rnbd-clt.h"
+
+static struct device *rnbd_dev;
+static struct class *rnbd_dev_class;
+static struct kobject *rnbd_devs_kobj;
+
+enum {
+       RNBD_OPT_ERR            = 0,
+       RNBD_OPT_DEST_PORT      = 1 << 0,
+       RNBD_OPT_PATH           = 1 << 1,
+       RNBD_OPT_DEV_PATH       = 1 << 2,
+       RNBD_OPT_ACCESS_MODE    = 1 << 3,
+       RNBD_OPT_SESSNAME       = 1 << 6,
+};
+
+static const unsigned int rnbd_opt_mandatory[] = {
+       RNBD_OPT_PATH,
+       RNBD_OPT_DEV_PATH,
+       RNBD_OPT_SESSNAME,
+};
+
+static const match_table_t rnbd_opt_tokens = {
+       {RNBD_OPT_PATH,         "path=%s"       },
+       {RNBD_OPT_DEV_PATH,     "device_path=%s"},
+       {RNBD_OPT_DEST_PORT,    "dest_port=%d"  },
+       {RNBD_OPT_ACCESS_MODE,  "access_mode=%s"},
+       {RNBD_OPT_SESSNAME,     "sessname=%s"   },
+       {RNBD_OPT_ERR,          NULL            },
+};
+
+struct rnbd_map_options {
+       char *sessname;
+       struct rtrs_addr *paths;
+       size_t *path_cnt;
+       char *pathname;
+       u16 *dest_port;
+       enum rnbd_access_mode *access_mode;
+};
+
+static int rnbd_clt_parse_map_options(const char *buf, size_t max_path_cnt,
+                                      struct rnbd_map_options *opt)
+{
+       char *options, *sep_opt;
+       char *p;
+       substring_t args[MAX_OPT_ARGS];
+       int opt_mask = 0;
+       int token;
+       int ret = -EINVAL;
+       int i, dest_port;
+       int p_cnt = 0;
+
+       options = kstrdup(buf, GFP_KERNEL);
+       if (!options)
+               return -ENOMEM;
+
+       sep_opt = strstrip(options);
+       while ((p = strsep(&sep_opt, " ")) != NULL) {
+               if (!*p)
+                       continue;
+
+               token = match_token(p, rnbd_opt_tokens, args);
+               opt_mask |= token;
+
+               switch (token) {
+               case RNBD_OPT_SESSNAME:
+                       p = match_strdup(args);
+                       if (!p) {
+                               ret = -ENOMEM;
+                               goto out;
+                       }
+                       if (strlen(p) > NAME_MAX) {
+                               pr_err("map_device: sessname too long\n");
+                               ret = -EINVAL;
+                               kfree(p);
+                               goto out;
+                       }
+                       strlcpy(opt->sessname, p, NAME_MAX);
+                       kfree(p);
+                       break;
+
+               case RNBD_OPT_PATH:
+                       if (p_cnt >= max_path_cnt) {
+                               pr_err("map_device: too many (> %zu) paths provided\n",
+                                      max_path_cnt);
+                               ret = -ENOMEM;
+                               goto out;
+                       }
+                       p = match_strdup(args);
+                       if (!p) {
+                               ret = -ENOMEM;
+                               goto out;
+                       }
+
+                       ret = rtrs_addr_to_sockaddr(p, strlen(p),
+                                                   *opt->dest_port,
+                                                   &opt->paths[p_cnt]);
+                       if (ret) {
+                               pr_err("Can't parse path %s: %d\n", p, ret);
+                               kfree(p);
+                               goto out;
+                       }
+
+                       p_cnt++;
+
+                       kfree(p);
+                       break;
+
+               case RNBD_OPT_DEV_PATH:
+                       p = match_strdup(args);
+                       if (!p) {
+                               ret = -ENOMEM;
+                               goto out;
+                       }
+                       if (strlen(p) > NAME_MAX) {
+                               pr_err("map_device: Device path too long\n");
+                               ret = -EINVAL;
+                               kfree(p);
+                               goto out;
+                       }
+                       strlcpy(opt->pathname, p, NAME_MAX);
+                       kfree(p);
+                       break;
+
+               case RNBD_OPT_DEST_PORT:
+                       if (match_int(args, &dest_port) || dest_port < 0 ||
+                           dest_port > 65535) {
+                               pr_err("bad destination port number parameter '%d'\n",
+                                      dest_port);
+                               ret = -EINVAL;
+                               goto out;
+                       }
+                       *opt->dest_port = dest_port;
+                       break;
+
+               case RNBD_OPT_ACCESS_MODE:
+                       p = match_strdup(args);
+                       if (!p) {
+                               ret = -ENOMEM;
+                               goto out;
+                       }
+
+                       if (!strcmp(p, "ro")) {
+                               *opt->access_mode = RNBD_ACCESS_RO;
+                       } else if (!strcmp(p, "rw")) {
+                               *opt->access_mode = RNBD_ACCESS_RW;
+                       } else if (!strcmp(p, "migration")) {
+                               *opt->access_mode = RNBD_ACCESS_MIGRATION;
+                       } else {
+                               pr_err("map_device: Invalid access_mode: '%s'\n",
+                                      p);
+                               ret = -EINVAL;
+                               kfree(p);
+                               goto out;
+                       }
+
+                       kfree(p);
+                       break;
+
+               default:
+                       pr_err("map_device: Unknown parameter or missing value '%s'\n",
+                              p);
+                       ret = -EINVAL;
+                       goto out;
+               }
+       }
+
+       for (i = 0; i < ARRAY_SIZE(rnbd_opt_mandatory); i++) {
+               if ((opt_mask & rnbd_opt_mandatory[i])) {
+                       ret = 0;
+               } else {
+                       pr_err("map_device: Parameters missing\n");
+                       ret = -EINVAL;
+                       break;
+               }
+       }
+
+out:
+       *opt->path_cnt = p_cnt;
+       kfree(options);
+       return ret;
+}
+
+static ssize_t state_show(struct kobject *kobj,
+                         struct kobj_attribute *attr, char *page)
+{
+       struct rnbd_clt_dev *dev;
+
+       dev = container_of(kobj, struct rnbd_clt_dev, kobj);
+
+       switch (dev->dev_state) {
+       case DEV_STATE_INIT:
+               return snprintf(page, PAGE_SIZE, "init\n");
+       case DEV_STATE_MAPPED:
+               /* TODO fix cli tool before changing to proper state */
+               return snprintf(page, PAGE_SIZE, "open\n");
+       case DEV_STATE_MAPPED_DISCONNECTED:
+               /* TODO fix cli tool before changing to proper state */
+               return snprintf(page, PAGE_SIZE, "closed\n");
+       case DEV_STATE_UNMAPPED:
+               return snprintf(page, PAGE_SIZE, "unmapped\n");
+       default:
+               return snprintf(page, PAGE_SIZE, "unknown\n");
+       }
+}
+
+static struct kobj_attribute rnbd_clt_state_attr = __ATTR_RO(state);
+
+static ssize_t mapping_path_show(struct kobject *kobj,
+                                struct kobj_attribute *attr, char *page)
+{
+       struct rnbd_clt_dev *dev;
+
+       dev = container_of(kobj, struct rnbd_clt_dev, kobj);
+
+       return scnprintf(page, PAGE_SIZE, "%s\n", dev->pathname);
+}
+
+static struct kobj_attribute rnbd_clt_mapping_path_attr =
+       __ATTR_RO(mapping_path);
+
+static ssize_t access_mode_show(struct kobject *kobj,
+                               struct kobj_attribute *attr, char *page)
+{
+       struct rnbd_clt_dev *dev;
+
+       dev = container_of(kobj, struct rnbd_clt_dev, kobj);
+
+       return snprintf(page, PAGE_SIZE, "%s\n",
+                       rnbd_access_mode_str(dev->access_mode));
+}
+
+static struct kobj_attribute rnbd_clt_access_mode =
+       __ATTR_RO(access_mode);
+
+static ssize_t rnbd_clt_unmap_dev_show(struct kobject *kobj,
+                                       struct kobj_attribute *attr, char *page)
+{
+       return scnprintf(page, PAGE_SIZE, "Usage: echo <normal|force> > %s\n",
+                        attr->attr.name);
+}
+
+static ssize_t rnbd_clt_unmap_dev_store(struct kobject *kobj,
+                                        struct kobj_attribute *attr,
+                                        const char *buf, size_t count)
+{
+       struct rnbd_clt_dev *dev;
+       char *opt, *options;
+       bool force;
+       int err;
+
+       opt = kstrdup(buf, GFP_KERNEL);
+       if (!opt)
+               return -ENOMEM;
+
+       options = strstrip(opt);
+       dev = container_of(kobj, struct rnbd_clt_dev, kobj);
+       if (sysfs_streq(options, "normal")) {
+               force = false;
+       } else if (sysfs_streq(options, "force")) {
+               force = true;
+       } else {
+               rnbd_clt_err(dev,
+                             "unmap_device: Invalid value: %s\n",
+                             options);
+               err = -EINVAL;
+               goto out;
+       }
+
+       rnbd_clt_info(dev, "Unmapping device, option: %s.\n",
+                      force ? "force" : "normal");
+
+       /*
+        * We take explicit module reference only for one reason: do not
+        * race with lockless rnbd_destroy_sessions().
+        */
+       if (!try_module_get(THIS_MODULE)) {
+               err = -ENODEV;
+               goto out;
+       }
+       err = rnbd_clt_unmap_device(dev, force, &attr->attr);
+       if (err) {
+               if (err != -EALREADY)
+                       rnbd_clt_err(dev, "unmap_device: %d\n",  err);
+               goto module_put;
+       }
+
+       /*
+        * Here device can be vanished!
+        */
+
+       err = count;
+
+module_put:
+       module_put(THIS_MODULE);
+out:
+       kfree(opt);
+
+       return err;
+}
+
+static struct kobj_attribute rnbd_clt_unmap_device_attr =
+       __ATTR(unmap_device, 0644, rnbd_clt_unmap_dev_show,
+              rnbd_clt_unmap_dev_store);
+
+static ssize_t rnbd_clt_resize_dev_show(struct kobject *kobj,
+                                        struct kobj_attribute *attr,
+                                        char *page)
+{
+       return scnprintf(page, PAGE_SIZE,
+                        "Usage: echo <new size in sectors> > %s\n",
+                        attr->attr.name);
+}
+
+static ssize_t rnbd_clt_resize_dev_store(struct kobject *kobj,
+                                         struct kobj_attribute *attr,
+                                         const char *buf, size_t count)
+{
+       int ret;
+       unsigned long sectors;
+       struct rnbd_clt_dev *dev;
+
+       dev = container_of(kobj, struct rnbd_clt_dev, kobj);
+
+       ret = kstrtoul(buf, 0, &sectors);
+       if (ret)
+               return ret;
+
+       ret = rnbd_clt_resize_disk(dev, (size_t)sectors);
+       if (ret)
+               return ret;
+
+       return count;
+}
+
+static struct kobj_attribute rnbd_clt_resize_dev_attr =
+       __ATTR(resize, 0644, rnbd_clt_resize_dev_show,
+              rnbd_clt_resize_dev_store);
+
+static ssize_t rnbd_clt_remap_dev_show(struct kobject *kobj,
+                                       struct kobj_attribute *attr, char *page)
+{
+       return scnprintf(page, PAGE_SIZE, "Usage: echo <1> > %s\n",
+                        attr->attr.name);
+}
+
+static ssize_t rnbd_clt_remap_dev_store(struct kobject *kobj,
+                                        struct kobj_attribute *attr,
+                                        const char *buf, size_t count)
+{
+       struct rnbd_clt_dev *dev;
+       char *opt, *options;
+       int err;
+
+       opt = kstrdup(buf, GFP_KERNEL);
+       if (!opt)
+               return -ENOMEM;
+
+       options = strstrip(opt);
+       dev = container_of(kobj, struct rnbd_clt_dev, kobj);
+       if (!sysfs_streq(options, "1")) {
+               rnbd_clt_err(dev,
+                             "remap_device: Invalid value: %s\n",
+                             options);
+               err = -EINVAL;
+               goto out;
+       }
+       err = rnbd_clt_remap_device(dev);
+       if (likely(!err))
+               err = count;
+
+out:
+       kfree(opt);
+
+       return err;
+}
+
+static struct kobj_attribute rnbd_clt_remap_device_attr =
+       __ATTR(remap_device, 0644, rnbd_clt_remap_dev_show,
+              rnbd_clt_remap_dev_store);
+
+static ssize_t session_show(struct kobject *kobj, struct kobj_attribute *attr,
+                           char *page)
+{
+       struct rnbd_clt_dev *dev;
+
+       dev = container_of(kobj, struct rnbd_clt_dev, kobj);
+
+       return scnprintf(page, PAGE_SIZE, "%s\n", dev->sess->sessname);
+}
+
+static struct kobj_attribute rnbd_clt_session_attr =
+       __ATTR_RO(session);
+
+static struct attribute *rnbd_dev_attrs[] = {
+       &rnbd_clt_unmap_device_attr.attr,
+       &rnbd_clt_resize_dev_attr.attr,
+       &rnbd_clt_remap_device_attr.attr,
+       &rnbd_clt_mapping_path_attr.attr,
+       &rnbd_clt_state_attr.attr,
+       &rnbd_clt_session_attr.attr,
+       &rnbd_clt_access_mode.attr,
+       NULL,
+};
+
+void rnbd_clt_remove_dev_symlink(struct rnbd_clt_dev *dev)
+{
+       /*
+        * The module_is_live() check is crucial and helps to avoid annoying
+        * sysfs warning raised in sysfs_remove_link(), when the whole sysfs
+        * path was just removed, see rnbd_close_sessions().
+        */
+       if (strlen(dev->blk_symlink_name) && module_is_live(THIS_MODULE))
+               sysfs_remove_link(rnbd_devs_kobj, dev->blk_symlink_name);
+}
+
+static struct kobj_type rnbd_dev_ktype = {
+       .sysfs_ops      = &kobj_sysfs_ops,
+       .default_attrs  = rnbd_dev_attrs,
+};
+
+static int rnbd_clt_add_dev_kobj(struct rnbd_clt_dev *dev)
+{
+       int ret;
+       struct kobject *gd_kobj = &disk_to_dev(dev->gd)->kobj;
+
+       ret = kobject_init_and_add(&dev->kobj, &rnbd_dev_ktype, gd_kobj, "%s",
+                                  "rnbd");
+       if (ret)
+               rnbd_clt_err(dev, "Failed to create device sysfs dir, err: %d\n",
+                             ret);
+
+       return ret;
+}
+
+static ssize_t rnbd_clt_map_device_show(struct kobject *kobj,
+                                        struct kobj_attribute *attr,
+                                        char *page)
+{
+       return scnprintf(page, PAGE_SIZE,
+                        "Usage: echo \"[dest_port=server port number] sessname=<name of the rtrs session> path=<[srcaddr@]dstaddr> [path=<[srcaddr@]dstaddr>] device_path=<full path on remote side> [access_mode=<ro|rw|migration>]\" > %s\n\naddr ::= [ ip:<ipv4> | ip:<ipv6> | gid:<gid> ]\n",
+                        attr->attr.name);
+}
+
+static int rnbd_clt_get_path_name(struct rnbd_clt_dev *dev, char *buf,
+                                  size_t len)
+{
+       int ret;
+       char pathname[NAME_MAX], *s;
+
+       strlcpy(pathname, dev->pathname, sizeof(pathname));
+       while ((s = strchr(pathname, '/')))
+               s[0] = '!';
+
+       ret = snprintf(buf, len, "%s", pathname);
+       if (ret >= len)
+               return -ENAMETOOLONG;
+
+       return 0;
+}
+
+static int rnbd_clt_add_dev_symlink(struct rnbd_clt_dev *dev)
+{
+       struct kobject *gd_kobj = &disk_to_dev(dev->gd)->kobj;
+       int ret;
+
+       ret = rnbd_clt_get_path_name(dev, dev->blk_symlink_name,
+                                     sizeof(dev->blk_symlink_name));
+       if (ret) {
+               rnbd_clt_err(dev, "Failed to get /sys/block symlink path, err: %d\n",
+                             ret);
+               goto out_err;
+       }
+
+       ret = sysfs_create_link(rnbd_devs_kobj, gd_kobj,
+                               dev->blk_symlink_name);
+       if (ret) {
+               rnbd_clt_err(dev, "Creating /sys/block symlink failed, err: %d\n",
+                             ret);
+               goto out_err;
+       }
+
+       return 0;
+
+out_err:
+       dev->blk_symlink_name[0] = '\0';
+       return ret;
+}
+
+static ssize_t rnbd_clt_map_device_store(struct kobject *kobj,
+                                         struct kobj_attribute *attr,
+                                         const char *buf, size_t count)
+{
+       struct rnbd_clt_dev *dev;
+       struct rnbd_map_options opt;
+       int ret;
+       char pathname[NAME_MAX];
+       char sessname[NAME_MAX];
+       enum rnbd_access_mode access_mode = RNBD_ACCESS_RW;
+       u16 port_nr = RTRS_PORT;
+
+       struct sockaddr_storage *addrs;
+       struct rtrs_addr paths[6];
+       size_t path_cnt;
+
+       opt.sessname = sessname;
+       opt.paths = paths;
+       opt.path_cnt = &path_cnt;
+       opt.pathname = pathname;
+       opt.dest_port = &port_nr;
+       opt.access_mode = &access_mode;
+       addrs = kcalloc(ARRAY_SIZE(paths) * 2, sizeof(*addrs), GFP_KERNEL);
+       if (!addrs)
+               return -ENOMEM;
+
+       for (path_cnt = 0; path_cnt < ARRAY_SIZE(paths); path_cnt++) {
+               paths[path_cnt].src = &addrs[path_cnt * 2];
+               paths[path_cnt].dst = &addrs[path_cnt * 2 + 1];
+       }
+
+       ret = rnbd_clt_parse_map_options(buf, ARRAY_SIZE(paths), &opt);
+       if (ret)
+               goto out;
+
+       pr_info("Mapping device %s on session %s, (access_mode: %s)\n",
+               pathname, sessname,
+               rnbd_access_mode_str(access_mode));
+
+       dev = rnbd_clt_map_device(sessname, paths, path_cnt, port_nr, pathname,
+                                 access_mode);
+       if (IS_ERR(dev)) {
+               ret = PTR_ERR(dev);
+               goto out;
+       }
+
+       ret = rnbd_clt_add_dev_kobj(dev);
+       if (ret)
+               goto unmap_dev;
+
+       ret = rnbd_clt_add_dev_symlink(dev);
+       if (ret)
+               goto unmap_dev;
+
+       kfree(addrs);
+       return count;
+
+unmap_dev:
+       rnbd_clt_unmap_device(dev, true, NULL);
+out:
+       kfree(addrs);
+       return ret;
+}
+
+static struct kobj_attribute rnbd_clt_map_device_attr =
+       __ATTR(map_device, 0644,
+              rnbd_clt_map_device_show, rnbd_clt_map_device_store);
+
+static struct attribute *default_attrs[] = {
+       &rnbd_clt_map_device_attr.attr,
+       NULL,
+};
+
+static struct attribute_group default_attr_group = {
+       .attrs = default_attrs,
+};
+
+static const struct attribute_group *default_attr_groups[] = {
+       &default_attr_group,
+       NULL,
+};
+
+int rnbd_clt_create_sysfs_files(void)
+{
+       int err;
+
+       rnbd_dev_class = class_create(THIS_MODULE, "rnbd-client");
+       if (IS_ERR(rnbd_dev_class))
+               return PTR_ERR(rnbd_dev_class);
+
+       rnbd_dev = device_create_with_groups(rnbd_dev_class, NULL,
+                                             MKDEV(0, 0), NULL,
+                                             default_attr_groups, "ctl");
+       if (IS_ERR(rnbd_dev)) {
+               err = PTR_ERR(rnbd_dev);
+               goto cls_destroy;
+       }
+       rnbd_devs_kobj = kobject_create_and_add("devices", &rnbd_dev->kobj);
+       if (!rnbd_devs_kobj) {
+               err = -ENOMEM;
+               goto dev_destroy;
+       }
+
+       return 0;
+
+dev_destroy:
+       device_destroy(rnbd_dev_class, MKDEV(0, 0));
+cls_destroy:
+       class_destroy(rnbd_dev_class);
+
+       return err;
+}
+
+void rnbd_clt_destroy_default_group(void)
+{
+       sysfs_remove_group(&rnbd_dev->kobj, &default_attr_group);
+}
+
+void rnbd_clt_destroy_sysfs_files(void)
+{
+       kobject_del(rnbd_devs_kobj);
+       kobject_put(rnbd_devs_kobj);
+       device_destroy(rnbd_dev_class, MKDEV(0, 0));
+       class_destroy(rnbd_dev_class);
+}