]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - c_src/libbcachefs.c
move Rust sources to top level, C sources into c_src
[bcachefs-tools-debian] / c_src / libbcachefs.c
diff --git a/c_src/libbcachefs.c b/c_src/libbcachefs.c
new file mode 100644 (file)
index 0000000..ef4cc71
--- /dev/null
@@ -0,0 +1,753 @@
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <libgen.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <uuid/uuid.h>
+
+#include "libbcachefs.h"
+#include "crypto.h"
+#include "libbcachefs/bcachefs_format.h"
+#include "libbcachefs/btree_cache.h"
+#include "libbcachefs/checksum.h"
+#include "libbcachefs/disk_groups.h"
+#include "libbcachefs/journal_seq_blacklist.h"
+#include "libbcachefs/opts.h"
+#include "libbcachefs/replicas.h"
+#include "libbcachefs/super-io.h"
+#include "tools-util.h"
+
+#define NSEC_PER_SEC   1000000000L
+
+static void init_layout(struct bch_sb_layout *l,
+                       unsigned block_size,
+                       unsigned sb_size,
+                       u64 sb_start, u64 sb_end)
+{
+       u64 sb_pos = sb_start;
+       unsigned i;
+
+       memset(l, 0, sizeof(*l));
+
+       l->magic                = BCHFS_MAGIC;
+       l->layout_type          = 0;
+       l->nr_superblocks       = 2;
+       l->sb_max_size_bits     = ilog2(sb_size);
+
+       /* Create two superblocks in the allowed range: */
+       for (i = 0; i < l->nr_superblocks; i++) {
+               if (sb_pos != BCH_SB_SECTOR)
+                       sb_pos = round_up(sb_pos, block_size >> 9);
+
+               l->sb_offset[i] = cpu_to_le64(sb_pos);
+               sb_pos += sb_size;
+       }
+
+       if (sb_pos > sb_end)
+               die("insufficient space for superblocks: start %llu end %llu > %llu size %u",
+                   sb_start, sb_pos, sb_end, sb_size);
+}
+
+/* minimum size filesystem we can create, given a bucket size: */
+static u64 min_size(unsigned bucket_size)
+{
+       return BCH_MIN_NR_NBUCKETS * bucket_size;
+}
+
+u64 bch2_pick_bucket_size(struct bch_opts opts, struct dev_opts *dev)
+{
+       u64 bucket_size;
+
+       if (dev->size < min_size(opts.block_size))
+               die("cannot format %s, too small (%llu bytes, min %llu)",
+                   dev->path, dev->size, min_size(opts.block_size));
+
+       /* Bucket size must be >= block size: */
+       bucket_size = opts.block_size;
+
+       /* Bucket size must be >= btree node size: */
+       if (opt_defined(opts, btree_node_size))
+               bucket_size = max_t(unsigned, bucket_size,
+                                        opts.btree_node_size);
+
+       /* Want a bucket size of at least 128k, if possible: */
+       bucket_size = max(bucket_size, 128ULL << 10);
+
+       if (dev->size >= min_size(bucket_size)) {
+               unsigned scale = max(1,
+                       ilog2(dev->size / min_size(bucket_size)) / 4);
+
+               scale = rounddown_pow_of_two(scale);
+
+               /* max bucket size 1 mb */
+               bucket_size = min(bucket_size * scale, 1ULL << 20);
+       } else {
+               do {
+                       bucket_size /= 2;
+               } while (dev->size < min_size(bucket_size));
+       }
+
+       return bucket_size;
+}
+
+void bch2_check_bucket_size(struct bch_opts opts, struct dev_opts *dev)
+{
+       if (dev->bucket_size < opts.block_size)
+               die("Bucket size (%llu) cannot be smaller than block size (%u)",
+                   dev->bucket_size, opts.block_size);
+
+       if (opt_defined(opts, btree_node_size) &&
+           dev->bucket_size < opts.btree_node_size)
+               die("Bucket size (%llu) cannot be smaller than btree node size (%u)",
+                   dev->bucket_size, opts.btree_node_size);
+
+       if (dev->nbuckets < BCH_MIN_NR_NBUCKETS)
+               die("Not enough buckets: %llu, need %u (bucket size %llu)",
+                   dev->nbuckets, BCH_MIN_NR_NBUCKETS, dev->bucket_size);
+
+       if (dev->bucket_size > (u32) U16_MAX << 9)
+               die("Bucket size (%llu) too big (max %u)",
+                   dev->bucket_size, (u32) U16_MAX << 9);
+}
+
+static unsigned parse_target(struct bch_sb_handle *sb,
+                            struct dev_opts *devs, size_t nr_devs,
+                            const char *s)
+{
+       struct dev_opts *i;
+       int idx;
+
+       if (!s)
+               return 0;
+
+       for (i = devs; i < devs + nr_devs; i++)
+               if (!strcmp(s, i->path))
+                       return dev_to_target(i - devs);
+
+       idx = bch2_disk_path_find(sb, s);
+       if (idx >= 0)
+               return group_to_target(idx);
+
+       die("Invalid target %s", s);
+       return 0;
+}
+
+struct bch_sb *bch2_format(struct bch_opt_strs fs_opt_strs,
+                          struct bch_opts      fs_opts,
+                          struct format_opts   opts,
+                          struct dev_opts      *devs,
+                          size_t               nr_devs)
+{
+       struct bch_sb_handle sb = { NULL };
+       struct dev_opts *i;
+       unsigned max_dev_block_size = 0;
+       unsigned opt_id;
+       u64 min_bucket_size = U64_MAX;
+
+       for (i = devs; i < devs + nr_devs; i++)
+               max_dev_block_size = max(max_dev_block_size, get_blocksize(i->bdev->bd_fd));
+
+       /* calculate block size: */
+       if (!opt_defined(fs_opts, block_size)) {
+               opt_set(fs_opts, block_size, max_dev_block_size);
+       } else if (fs_opts.block_size < max_dev_block_size)
+               die("blocksize too small: %u, must be greater than device blocksize %u",
+                   fs_opts.block_size, max_dev_block_size);
+
+       /* get device size, if it wasn't specified: */
+       for (i = devs; i < devs + nr_devs; i++)
+               if (!i->size)
+                       i->size = get_size(i->bdev->bd_fd);
+
+       /* calculate bucket sizes: */
+       for (i = devs; i < devs + nr_devs; i++)
+               min_bucket_size = min(min_bucket_size,
+                       i->bucket_size ?: bch2_pick_bucket_size(fs_opts, i));
+
+       for (i = devs; i < devs + nr_devs; i++)
+               if (!i->bucket_size)
+                       i->bucket_size = min_bucket_size;
+
+       for (i = devs; i < devs + nr_devs; i++) {
+               i->nbuckets = i->size / i->bucket_size;
+               bch2_check_bucket_size(fs_opts, i);
+       }
+
+       /* calculate btree node size: */
+       if (!opt_defined(fs_opts, btree_node_size)) {
+               /* 256k default btree node size */
+               opt_set(fs_opts, btree_node_size, 256 << 10);
+
+               for (i = devs; i < devs + nr_devs; i++)
+                       fs_opts.btree_node_size =
+                               min_t(unsigned, fs_opts.btree_node_size,
+                                     i->bucket_size);
+       }
+
+       if (uuid_is_null(opts.uuid.b))
+               uuid_generate(opts.uuid.b);
+
+       if (bch2_sb_realloc(&sb, 0))
+               die("insufficient memory");
+
+       sb.sb->version          = le16_to_cpu(opts.version);
+       sb.sb->version_min      = le16_to_cpu(opts.version);
+       sb.sb->magic            = BCHFS_MAGIC;
+       sb.sb->user_uuid        = opts.uuid;
+       sb.sb->nr_devices       = nr_devs;
+
+       if (opts.version == bcachefs_metadata_version_current)
+               sb.sb->features[0] |= cpu_to_le64(BCH_SB_FEATURES_ALL);
+
+       uuid_generate(sb.sb->uuid.b);
+
+       if (opts.label)
+               memcpy(sb.sb->label,
+                      opts.label,
+                      min(strlen(opts.label), sizeof(sb.sb->label)));
+
+       for (opt_id = 0;
+            opt_id < bch2_opts_nr;
+            opt_id++) {
+               u64 v;
+
+               v = bch2_opt_defined_by_id(&fs_opts, opt_id)
+                       ? bch2_opt_get_by_id(&fs_opts, opt_id)
+                       : bch2_opt_get_by_id(&bch2_opts_default, opt_id);
+
+               __bch2_opt_set_sb(sb.sb, &bch2_opt_table[opt_id], v);
+       }
+
+       struct timespec now;
+       if (clock_gettime(CLOCK_REALTIME, &now))
+               die("error getting current time: %m");
+
+       sb.sb->time_base_lo     = cpu_to_le64(now.tv_sec * NSEC_PER_SEC + now.tv_nsec);
+       sb.sb->time_precision   = cpu_to_le32(1);
+
+       /* Member info: */
+       struct bch_sb_field_members_v2 *mi =
+               bch2_sb_field_resize(&sb, members_v2,
+                       (sizeof(*mi) + sizeof(struct bch_member) *
+                       nr_devs) / sizeof(u64));
+       mi->member_bytes = cpu_to_le16(sizeof(struct bch_member));
+       for (i = devs; i < devs + nr_devs; i++) {
+               struct bch_member *m = bch2_members_v2_get_mut(sb.sb, (i - devs));
+
+               uuid_generate(m->uuid.b);
+               m->nbuckets     = cpu_to_le64(i->nbuckets);
+               m->first_bucket = 0;
+               m->bucket_size  = cpu_to_le16(i->bucket_size >> 9);
+
+               SET_BCH_MEMBER_DISCARD(m,       i->discard);
+               SET_BCH_MEMBER_DATA_ALLOWED(m,  i->data_allowed);
+               SET_BCH_MEMBER_DURABILITY(m,    i->durability + 1);
+       }
+
+       /* Disk labels*/
+       for (i = devs; i < devs + nr_devs; i++) {
+               struct bch_member *m;
+               int idx;
+
+               if (!i->label)
+                       continue;
+
+               idx = bch2_disk_path_find_or_create(&sb, i->label);
+               if (idx < 0)
+                       die("error creating disk path: %s", strerror(-idx));
+
+               /*
+                * Recompute mi and m after each sb modification: its location
+                * in memory may have changed due to reallocation.
+                */
+               m = bch2_members_v2_get_mut(sb.sb, (i - devs));
+               SET_BCH_MEMBER_GROUP(m, idx + 1);
+       }
+
+       SET_BCH_SB_FOREGROUND_TARGET(sb.sb,
+               parse_target(&sb, devs, nr_devs, fs_opt_strs.foreground_target));
+       SET_BCH_SB_BACKGROUND_TARGET(sb.sb,
+               parse_target(&sb, devs, nr_devs, fs_opt_strs.background_target));
+       SET_BCH_SB_PROMOTE_TARGET(sb.sb,
+               parse_target(&sb, devs, nr_devs, fs_opt_strs.promote_target));
+       SET_BCH_SB_METADATA_TARGET(sb.sb,
+               parse_target(&sb, devs, nr_devs, fs_opt_strs.metadata_target));
+
+       /* Crypt: */
+       if (opts.encrypted) {
+               struct bch_sb_field_crypt *crypt =
+                       bch2_sb_field_resize(&sb, crypt, sizeof(*crypt) / sizeof(u64));
+
+               bch_sb_crypt_init(sb.sb, crypt, opts.passphrase);
+               SET_BCH_SB_ENCRYPTION_TYPE(sb.sb, 1);
+       }
+
+       bch2_sb_members_cpy_v2_v1(&sb);
+
+       for (i = devs; i < devs + nr_devs; i++) {
+               u64 size_sectors = i->size >> 9;
+
+               sb.sb->dev_idx = i - devs;
+
+               if (!i->sb_offset) {
+                       i->sb_offset    = BCH_SB_SECTOR;
+                       i->sb_end       = size_sectors;
+               }
+
+               init_layout(&sb.sb->layout, fs_opts.block_size,
+                           opts.superblock_size,
+                           i->sb_offset, i->sb_end);
+
+               /*
+                * Also create a backup superblock at the end of the disk:
+                *
+                * If we're not creating a superblock at the default offset, it
+                * means we're being run from the migrate tool and we could be
+                * overwriting existing data if we write to the end of the disk:
+                */
+               if (i->sb_offset == BCH_SB_SECTOR) {
+                       struct bch_sb_layout *l = &sb.sb->layout;
+                       u64 backup_sb = size_sectors - (1 << l->sb_max_size_bits);
+
+                       backup_sb = rounddown(backup_sb, i->bucket_size >> 9);
+                       l->sb_offset[l->nr_superblocks++] = cpu_to_le64(backup_sb);
+               }
+
+               if (i->sb_offset == BCH_SB_SECTOR) {
+                       /* Zero start of disk */
+                       static const char zeroes[BCH_SB_SECTOR << 9];
+
+                       xpwrite(i->bdev->bd_fd, zeroes, BCH_SB_SECTOR << 9, 0,
+                               "zeroing start of disk");
+               }
+
+               bch2_super_write(i->bdev->bd_fd, sb.sb);
+               close(i->bdev->bd_fd);
+       }
+
+       return sb.sb;
+}
+
+void bch2_super_write(int fd, struct bch_sb *sb)
+{
+       struct nonce nonce = { 0 };
+       unsigned bs = get_blocksize(fd);
+
+       unsigned i;
+       for (i = 0; i < sb->layout.nr_superblocks; i++) {
+               sb->offset = sb->layout.sb_offset[i];
+
+               if (sb->offset == BCH_SB_SECTOR) {
+                       /* Write backup layout */
+
+                       BUG_ON(bs > 4096);
+
+                       char *buf = aligned_alloc(bs, bs);
+                       xpread(fd, buf, bs, 4096 - bs);
+                       memcpy(buf + bs - sizeof(sb->layout),
+                              &sb->layout,
+                              sizeof(sb->layout));
+                       xpwrite(fd, buf, bs, 4096 - bs,
+                               "backup layout");
+                       free(buf);
+
+               }
+
+               sb->csum = csum_vstruct(NULL, BCH_SB_CSUM_TYPE(sb), nonce, sb);
+               xpwrite(fd, sb, round_up(vstruct_bytes(sb), bs),
+                       le64_to_cpu(sb->offset) << 9,
+                       "superblock");
+       }
+
+       fsync(fd);
+}
+
+struct bch_sb *__bch2_super_read(int fd, u64 sector)
+{
+       struct bch_sb sb, *ret;
+
+       xpread(fd, &sb, sizeof(sb), sector << 9);
+
+       if (memcmp(&sb.magic, &BCACHE_MAGIC, sizeof(sb.magic)) &&
+           memcmp(&sb.magic, &BCHFS_MAGIC, sizeof(sb.magic)))
+               die("not a bcachefs superblock");
+
+       size_t bytes = vstruct_bytes(&sb);
+
+       ret = malloc(bytes);
+
+       xpread(fd, ret, bytes, sector << 9);
+
+       return ret;
+}
+
+/* ioctl interface: */
+
+/* Global control device: */
+int bcachectl_open(void)
+{
+       return xopen("/dev/bcachefs-ctl", O_RDWR);
+}
+
+/* Filesystem handles (ioctl, sysfs dir): */
+
+#define SYSFS_BASE "/sys/fs/bcachefs/"
+
+void bcache_fs_close(struct bchfs_handle fs)
+{
+       close(fs.ioctl_fd);
+       close(fs.sysfs_fd);
+}
+
+struct bchfs_handle bcache_fs_open(const char *path)
+{
+       struct bchfs_handle ret;
+
+       if (!uuid_parse(path, ret.uuid.b)) {
+               /* It's a UUID, look it up in sysfs: */
+               char *sysfs = mprintf(SYSFS_BASE "%s", path);
+               ret.sysfs_fd = xopen(sysfs, O_RDONLY);
+
+               char *minor = read_file_str(ret.sysfs_fd, "minor");
+               char *ctl = mprintf("/dev/bcachefs%s-ctl", minor);
+               ret.ioctl_fd = xopen(ctl, O_RDWR);
+
+               free(sysfs);
+               free(minor);
+               free(ctl);
+       } else {
+               /* It's a path: */
+               ret.ioctl_fd = open(path, O_RDONLY);
+               if (ret.ioctl_fd < 0)
+                       die("Error opening filesystem at %s: %m", path);
+
+               struct bch_ioctl_query_uuid uuid;
+               if (ioctl(ret.ioctl_fd, BCH_IOCTL_QUERY_UUID, &uuid) < 0)
+                       die("error opening %s: not a bcachefs filesystem", path);
+
+               ret.uuid = uuid.uuid;
+
+               char uuid_str[40];
+               uuid_unparse(uuid.uuid.b, uuid_str);
+
+               char *sysfs = mprintf(SYSFS_BASE "%s", uuid_str);
+               ret.sysfs_fd = xopen(sysfs, O_RDONLY);
+               free(sysfs);
+       }
+
+       return ret;
+}
+
+/*
+ * Given a path to a block device, open the filesystem it belongs to; also
+ * return the device's idx:
+ */
+struct bchfs_handle bchu_fs_open_by_dev(const char *path, int *idx)
+{
+       struct bch_opts opts = bch2_opts_empty();
+       char buf[1024], *uuid_str;
+
+       struct stat stat = xstat(path);
+
+       if (S_ISBLK(stat.st_mode)) {
+               char *sysfs = mprintf("/sys/dev/block/%u:%u/bcachefs",
+                                     major(stat.st_dev),
+                                     minor(stat.st_dev));
+
+               ssize_t len = readlink(sysfs, buf, sizeof(buf));
+               free(sysfs);
+
+               if (len <= 0)
+                       goto read_super;
+
+               char *p = strrchr(buf, '/');
+               if (!p || sscanf(p + 1, "dev-%u", idx) != 1)
+                       die("error parsing sysfs");
+
+               *p = '\0';
+               p = strrchr(buf, '/');
+               uuid_str = p + 1;
+       } else {
+read_super:
+               opt_set(opts, noexcl,   true);
+               opt_set(opts, nochanges, true);
+
+               struct bch_sb_handle sb;
+               int ret = bch2_read_super(path, &opts, &sb);
+               if (ret)
+                       die("Error opening %s: %s", path, strerror(-ret));
+
+               *idx = sb.sb->dev_idx;
+               uuid_str = buf;
+               uuid_unparse(sb.sb->user_uuid.b, uuid_str);
+
+               bch2_free_super(&sb);
+       }
+
+       return bcache_fs_open(uuid_str);
+}
+
+int bchu_dev_path_to_idx(struct bchfs_handle fs, const char *dev_path)
+{
+       int idx;
+       struct bchfs_handle fs2 = bchu_fs_open_by_dev(dev_path, &idx);
+
+       if (memcmp(&fs.uuid, &fs2.uuid, sizeof(fs.uuid)))
+               idx = -1;
+       bcache_fs_close(fs2);
+       return idx;
+}
+
+int bchu_data(struct bchfs_handle fs, struct bch_ioctl_data cmd)
+{
+       int progress_fd = xioctl(fs.ioctl_fd, BCH_IOCTL_DATA, &cmd);
+
+       while (1) {
+               struct bch_ioctl_data_event e;
+
+               if (read(progress_fd, &e, sizeof(e)) != sizeof(e))
+                       die("error reading from progress fd %m");
+
+               if (e.type)
+                       continue;
+
+               if (e.p.data_type == U8_MAX)
+                       break;
+
+               printf("\33[2K\r");
+
+               printf("%llu%% complete: current position %s",
+                      e.p.sectors_total
+                      ? e.p.sectors_done * 100 / e.p.sectors_total
+                      : 0,
+                      bch2_data_types[e.p.data_type]);
+
+               switch (e.p.data_type) {
+               case BCH_DATA_btree:
+               case BCH_DATA_user:
+                       printf(" %s:%llu:%llu",
+                              bch2_btree_id_str(e.p.btree_id),
+                              e.p.pos.inode,
+                              e.p.pos.offset);
+               }
+
+               fflush(stdout);
+               sleep(1);
+       }
+       printf("\nDone\n");
+
+       close(progress_fd);
+       return 0;
+}
+
+/* option parsing */
+
+void bch2_opt_strs_free(struct bch_opt_strs *opts)
+{
+       unsigned i;
+
+       for (i = 0; i < bch2_opts_nr; i++) {
+               free(opts->by_id[i]);
+               opts->by_id[i] = NULL;
+       }
+}
+
+struct bch_opt_strs bch2_cmdline_opts_get(int *argc, char *argv[],
+                                         unsigned opt_types)
+{
+       struct bch_opt_strs opts;
+       unsigned i = 1;
+
+       memset(&opts, 0, sizeof(opts));
+
+       while (i < *argc) {
+               char *optstr = strcmp_prefix(argv[i], "--");
+               char *valstr = NULL, *p;
+               int optid, nr_args = 1;
+
+               if (!optstr) {
+                       i++;
+                       continue;
+               }
+
+               optstr = strdup(optstr);
+
+               p = optstr;
+               while (isalpha(*p) || *p == '_')
+                       p++;
+
+               if (*p == '=') {
+                       *p = '\0';
+                       valstr = p + 1;
+               }
+
+               optid = bch2_opt_lookup(optstr);
+               if (optid < 0 ||
+                   !(bch2_opt_table[optid].flags & opt_types)) {
+                       i++;
+                       goto next;
+               }
+
+               if (!valstr &&
+                   bch2_opt_table[optid].type != BCH_OPT_BOOL) {
+                       nr_args = 2;
+                       valstr = argv[i + 1];
+               }
+
+               if (!valstr)
+                       valstr = "1";
+
+               opts.by_id[optid] = strdup(valstr);
+
+               *argc -= nr_args;
+               memmove(&argv[i],
+                       &argv[i + nr_args],
+                       sizeof(char *) * (*argc - i));
+               argv[*argc] = NULL;
+next:
+               free(optstr);
+       }
+
+       return opts;
+}
+
+struct bch_opts bch2_parse_opts(struct bch_opt_strs strs)
+{
+       struct bch_opts opts = bch2_opts_empty();
+       struct printbuf err = PRINTBUF;
+       unsigned i;
+       int ret;
+       u64 v;
+
+       for (i = 0; i < bch2_opts_nr; i++) {
+               if (!strs.by_id[i])
+                       continue;
+
+               ret = bch2_opt_parse(NULL,
+                                    &bch2_opt_table[i],
+                                    strs.by_id[i], &v, &err);
+               if (ret < 0)
+                       die("Invalid option %s", err.buf);
+
+               bch2_opt_set_by_id(&opts, i, v);
+       }
+
+       printbuf_exit(&err);
+       return opts;
+}
+
+#define newline(c)             \
+       do {                    \
+               printf("\n");   \
+               c = 0;          \
+       } while(0)
+void bch2_opts_usage(unsigned opt_types)
+{
+       const struct bch_option *opt;
+       unsigned i, c = 0, helpcol = 30;
+
+
+
+       for (opt = bch2_opt_table;
+            opt < bch2_opt_table + bch2_opts_nr;
+            opt++) {
+               if (!(opt->flags & opt_types))
+                       continue;
+
+               c += printf("      --%s", opt->attr.name);
+
+               switch (opt->type) {
+               case BCH_OPT_BOOL:
+                       break;
+               case BCH_OPT_STR:
+                       c += printf("=(");
+                       for (i = 0; opt->choices[i]; i++) {
+                               if (i)
+                                       c += printf("|");
+                               c += printf("%s", opt->choices[i]);
+                       }
+                       c += printf(")");
+                       break;
+               default:
+                       c += printf("=%s", opt->hint);
+                       break;
+               }
+
+               if (opt->help) {
+                       const char *l = opt->help;
+
+                       if (c >= helpcol)
+                               newline(c);
+
+                       while (1) {
+                               const char *n = strchrnul(l, '\n');
+
+                               while (c < helpcol) {
+                                       putchar(' ');
+                                       c++;
+                               }
+                               printf("%.*s", (int) (n - l), l);
+                               newline(c);
+
+                               if (!*n)
+                                       break;
+                               l = n + 1;
+                       }
+               } else {
+                       newline(c);
+               }
+       }
+}
+
+dev_names bchu_fs_get_devices(struct bchfs_handle fs)
+{
+       DIR *dir = fdopendir(fs.sysfs_fd);
+       struct dirent *d;
+       dev_names devs;
+
+       darray_init(&devs);
+
+       while ((errno = 0), (d = readdir(dir))) {
+               struct dev_name n = { 0, NULL, NULL };
+
+               if (sscanf(d->d_name, "dev-%u", &n.idx) != 1)
+                       continue;
+
+               char *block_attr = mprintf("dev-%u/block", n.idx);
+
+               char sysfs_block_buf[4096];
+               ssize_t r = readlinkat(fs.sysfs_fd, block_attr,
+                                      sysfs_block_buf, sizeof(sysfs_block_buf));
+               if (r > 0) {
+                       sysfs_block_buf[r] = '\0';
+                       n.dev = strdup(basename(sysfs_block_buf));
+               }
+
+               free(block_attr);
+
+               char *label_attr = mprintf("dev-%u/label", n.idx);
+               n.label = read_file_str(fs.sysfs_fd, label_attr);
+               free(label_attr);
+
+               char *durability_attr = mprintf("dev-%u/durability", n.idx);
+               n.durability = read_file_u64(fs.sysfs_fd, durability_attr);
+               free(durability_attr);
+
+               darray_push(&devs, n);
+       }
+
+       closedir(dir);
+
+       return devs;
+}