[PATCH v3] erofs-utils: mount: add OCI recovery support for NBD reattach
ChengyuZhu6
hudson at cyzhu.com
Tue Sep 9 20:28:01 AEST 2025
From: Chengyu Zhu <hudsonzhu at tencent.com>
This commit implements recovery support for OCI-based NBD mounts,
allowing the system to properly reattach NBD devices after
NBD disconnection.
Signed-off-by: Chengyu Zhu <hudsonzhu at tencent.com>
---
lib/liberofs_oci.h | 5 ++
lib/remotes/oci.c | 129 +++++++++++++++++++++++++++++++++++++++++
mount/main.c | 141 ++++++++++++++++++++++++++++++++++++---------
3 files changed, 247 insertions(+), 28 deletions(-)
diff --git a/lib/liberofs_oci.h b/lib/liberofs_oci.h
index 01a83aa..e910e6a 100644
--- a/lib/liberofs_oci.h
+++ b/lib/liberofs_oci.h
@@ -71,6 +71,11 @@ int ocierofs_build_trees(struct erofs_importer *importer,
const struct ocierofs_config *cfg);
int ocierofs_io_open(struct erofs_vfile *vf, const struct ocierofs_config *cfg);
+int ocierofs_b64_encode_userpass(const char *username, const char *password,
+ char **out_b64);
+int ocierofs_b64_decode_userpass(const char *b64,
+ char **out_user, char **out_pass);
+
#ifdef __cplusplus
}
#endif
diff --git a/lib/remotes/oci.c b/lib/remotes/oci.c
index de18daa..4e46e0b 100644
--- a/lib/remotes/oci.c
+++ b/lib/remotes/oci.c
@@ -1471,6 +1471,135 @@ int ocierofs_io_open(struct erofs_vfile *vfile, const struct ocierofs_config *cf
*(struct ocierofs_iostream **)vfile->payload = oci_iostream;
return 0;
}
+
+static const char ocierofs_b64_tbl[] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+int ocierofs_b64_encode_userpass(const char *username, const char *password,
+ char **out_b64)
+{
+ const unsigned char *in;
+ size_t ulen = username ? strlen(username) : 0;
+ size_t plen = password ? strlen(password) : 0;
+ size_t inlen = ulen + 1 + plen;
+ size_t outlen;
+ unsigned char *buf;
+ char *out;
+ size_t i, j;
+ unsigned int octet_a, octet_b, octet_c, triple;
+
+ if (!out_b64)
+ return -EINVAL;
+ *out_b64 = NULL;
+
+ buf = malloc(inlen + 1);
+ if (!buf)
+ return -ENOMEM;
+ memcpy(buf, username ? username : "", ulen);
+ buf[ulen] = ':';
+ memcpy(buf + ulen + 1, password ? password : "", plen);
+ buf[inlen] = '\0';
+ in = buf;
+
+ outlen = 4 * ((inlen + 2) / 3);
+ out = malloc(outlen + 1);
+ if (!out) {
+ free(buf);
+ return -ENOMEM;
+ }
+
+ for (i = 0, j = 0; i < inlen;) {
+ octet_a = i < inlen ? in[i++] : 0;
+ octet_b = i < inlen ? in[i++] : 0;
+ octet_c = i < inlen ? in[i++] : 0;
+ triple = (octet_a << 16) | (octet_b << 8) | octet_c;
+ out[j++] = ocierofs_b64_tbl[(triple >> 18) & 0x3F];
+ out[j++] = ocierofs_b64_tbl[(triple >> 12) & 0x3F];
+ out[j++] = (i - 1 > inlen) ? '=' : ocierofs_b64_tbl[(triple >> 6) & 0x3F];
+ out[j++] = (i > inlen) ? '=' : ocierofs_b64_tbl[triple & 0x3F];
+ }
+ if (inlen % 3 == 1) {
+ out[outlen - 1] = '=';
+ out[outlen - 2] = '=';
+ } else if (inlen % 3 == 2) {
+ out[outlen - 1] = '=';
+ }
+ out[outlen] = '\0';
+ free(buf);
+ *out_b64 = out;
+ return 0;
+}
+
+static int ocierofs_b64_inv(int c)
+{
+ if (c >= 'A' && c <= 'Z')
+ return c - 'A';
+ if (c >= 'a' && c <= 'z')
+ return c - 'a' + 26;
+ if (c >= '0' && c <= '9')
+ return c - '0' + 52;
+ if (c == '+')
+ return 62;
+ if (c == '/')
+ return 63;
+ return -1;
+}
+
+int ocierofs_b64_decode_userpass(const char *b64,
+ char **out_user, char **out_pass)
+{
+ size_t len, i, j;
+ unsigned char *out;
+ int val = 0, valb = -8, c;
+
+ if (!b64 || !out_user || !out_pass)
+ return -EINVAL;
+ *out_user = NULL;
+ *out_pass = NULL;
+
+ len = strlen(b64);
+ out = malloc(len * 3 / 4 + 1);
+ if (!out)
+ return -ENOMEM;
+
+ for (i = 0, j = 0; i < len; i++) {
+ c = b64[i];
+
+ if (c == '=')
+ break;
+ c = ocierofs_b64_inv(c);
+ if (c < 0)
+ continue;
+ val = (val << 6) + c;
+ valb += 6;
+ if (valb >= 0) {
+ out[j++] = (unsigned char)((val >> valb) & 0xFF);
+ valb -= 8;
+ }
+ }
+ out[j] = '\0';
+
+ {
+ char *colon = (char *)memchr(out, ':', j);
+
+ if (!colon) {
+ free(out);
+ return -EINVAL;
+ }
+ *colon = '\0';
+ *out_user = strdup((char *)out);
+ *out_pass = strdup(colon + 1);
+ free(out);
+ if (!*out_user || !*out_pass) {
+ free(*out_user);
+ free(*out_pass);
+ *out_user = *out_pass = NULL;
+ return -ENOMEM;
+ }
+ }
+ return 0;
+}
+
#else
int ocierofs_io_open(struct erofs_vfile *vfile, const struct ocierofs_config *cfg)
{
diff --git a/mount/main.c b/mount/main.c
index c52ac3b..4fe54c5 100644
--- a/mount/main.c
+++ b/mount/main.c
@@ -401,10 +401,48 @@ out_closefd:
return err;
}
-static char *erofsmount_write_recovery_info(const char *source)
+static int erofsmount_write_recovery_oci(FILE *f, struct erofs_nbd_source *source)
+{
+ char *b64cred = NULL;
+ int ret;
+
+ if (source->ocicfg.username || source->ocicfg.password) {
+ ret = ocierofs_b64_encode_userpass(
+ source->ocicfg.username,
+ source->ocicfg.password,
+ &b64cred);
+ if (ret) {
+ fclose(f);
+ return ret;
+ }
+ }
+ ret = fprintf(f, "OCI_LAYER %s %s %s %d\n",
+ source->ocicfg.image_ref ?: "",
+ source->ocicfg.platform ?: "",
+ b64cred ?: "",
+ source->ocicfg.layer_index);
+ free(b64cred);
+ return ret < 0 ? -ENOMEM : 0;
+}
+
+static int erofsmount_write_recovery_local(FILE *f, struct erofs_nbd_source *source)
{
- char recp[] = "/var/run/erofs/mountnbd_XXXXXX";
char *realp;
+ int err;
+
+ realp = realpath(source->device_path, NULL);
+ if (!realp)
+ return -errno;
+
+ /* TYPE<LOCAL> <SOURCE PATH>\n(more..) */
+ err = fprintf(f, "LOCAL %s\n", realp) < 0;
+ free(realp);
+ return err ? -ENOMEM : 0;
+}
+
+static char *erofsmount_write_recovery_info(struct erofs_nbd_source *source)
+{
+ char recp[] = "/var/run/erofs/mountnbd_XXXXXX";
int fd, err;
FILE *f;
@@ -424,20 +462,62 @@ static char *erofsmount_write_recovery_info(const char *source)
return ERR_PTR(-errno);
}
- realp = realpath(source, NULL);
- if (!realp) {
- fclose(f);
- return ERR_PTR(-errno);
+ if (source->type == EROFSNBD_SOURCE_OCI) {
+ err = erofsmount_write_recovery_oci(f, source);
+ if (err) {
+ fclose(f);
+ return ERR_PTR(err);
+ }
+ } else {
+ err = erofsmount_write_recovery_local(f, source);
+ if (err) {
+ fclose(f);
+ return ERR_PTR(err);
+ }
}
- /* TYPE<LOCAL> <SOURCE PATH>\n(more..) */
- err = fprintf(f, "LOCAL %s\n", realp) < 0;
+
fclose(f);
- free(realp);
- if (err)
- return ERR_PTR(-ENOMEM);
return strdup(recp) ?: ERR_PTR(-ENOMEM);
}
+static int erofsmount_parse_recovery_ocilayer(struct ocierofs_config *oci_cfg,
+ char *source)
+{
+ char *platform, *b64cred, *layer_str;
+ int err;
+ char *endptr;
+ unsigned long v;
+
+ platform = strchr(source, ' ');
+ if (platform) {
+ *platform++ = '\0';
+ oci_cfg->image_ref = source;
+ oci_cfg->platform = platform;
+ } else {
+ oci_cfg->image_ref = source;
+ }
+
+ b64cred = strchr(platform ?: source, ' ');
+ if (b64cred) {
+ *b64cred++ = '\0';
+ err = ocierofs_b64_decode_userpass(b64cred,
+ &oci_cfg->username,
+ &oci_cfg->password);
+ if (err)
+ return err;
+ }
+
+ layer_str = strchr(b64cred ?: (platform ?: source), ' ');
+ if (layer_str) {
+ *layer_str++ = '\0';
+ v = strtoul(layer_str, &endptr, 10);
+ if (endptr == layer_str || *endptr != '\0')
+ return -EINVAL;
+ oci_cfg->layer_index = (int)v;
+ }
+ return 0;
+}
+
static int erofsmount_nbd_fix_backend_linkage(int num, char **recp)
{
char *newrecp;
@@ -491,15 +571,10 @@ static int erofsmount_startnbd_nl(pid_t *pid, struct erofs_nbd_source *source)
exit(EXIT_FAILURE);
ctx.vd.fd = err;
}
-
- if (source->type == EROFSNBD_SOURCE_LOCAL) {
- recp = erofsmount_write_recovery_info(source->device_path);
- if (IS_ERR(recp)) {
- erofs_io_close(&ctx.vd);
- exit(EXIT_FAILURE);
- }
- } else {
- recp = NULL;
+ recp = erofsmount_write_recovery_info(source);
+ if (IS_ERR(recp)) {
+ erofs_io_close(&ctx.vd);
+ exit(EXIT_FAILURE);
}
num = -1;
@@ -595,19 +670,29 @@ static int erofsmount_reattach(const char *target)
*(source++) = '\0';
}
- if (strcmp(line, "LOCAL")) {
+ if (!strcmp(line, "LOCAL")) {
+ err = open(source, O_RDONLY);
+ if (err < 0) {
+ err = -errno;
+ goto err_line;
+ }
+ ctx.vd.fd = err;
+ } else if (!strcmp(line, "OCI_LAYER")) {
+ struct ocierofs_config oci_cfg = {};
+
+ err = erofsmount_parse_recovery_ocilayer(&oci_cfg, source);
+ if (err)
+ goto err_line;
+
+ err = ocierofs_io_open(&ctx.vd, &oci_cfg);
+ if (err < 0)
+ goto err_line;
+ } else {
err = -EOPNOTSUPP;
erofs_err("unsupported source type %s recorded in recovery file", line);
goto err_line;
}
- err = open(source, O_RDONLY);
- if (err < 0) {
- err = -errno;
- goto err_line;
- }
- ctx.vd.fd = err;
-
err = erofs_nbd_nl_reconnect(nbdnum, identifier);
if (err >= 0) {
ctx.sk.fd = err;
--
2.51.0
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