[PATCH v2] erofs-utils: add source support for tarindex and gzran
Gao Xiang
hsiangkao at linux.alibaba.com
Sun Sep 28 18:16:20 AEST 2025
On 2025/9/28 16:02, ChengyuZhu6 wrote:
> From: Chengyu Zhu <hudsonzhu at tencent.com>
>
> Add support for combining tarindex files with remote OCI blobs
> through a new source mechanism. This enables local metadata
> storage while keeping blob data in remote registries.
>
> e.g.:
> mount.erofs -t erofs.nbd -o \
> 'oci.blob=13b7e9...,oci.platform=linux/amd64,\
> oci.tarindex=ubuntu.erofs,oci.zinfo=ubuntu.zinfo' \
> ubuntu:20.04 /mnt
>
> Signed-off-by: Chengyu Zhu <hudsonzhu at tencent.com>
> ---
> lib/liberofs_oci.h | 2 +
> lib/remotes/oci.c | 20 ---
> mount/main.c | 397 ++++++++++++++++++++++++++++++++++++++++++++-
> 3 files changed, 392 insertions(+), 27 deletions(-)
>
> diff --git a/lib/liberofs_oci.h b/lib/liberofs_oci.h
> index 71c8879..5298f18 100644
> --- a/lib/liberofs_oci.h
> +++ b/lib/liberofs_oci.h
> @@ -35,6 +35,8 @@ struct ocierofs_config {
> char *password;
> char *blob_digest;
> int layer_index;
> + char *tarindex_path;
> + char *zinfo_path;
> };
>
> struct ocierofs_layer_info {
> diff --git a/lib/remotes/oci.c b/lib/remotes/oci.c
> index b2f1f59..b25e0b2 100644
> --- a/lib/remotes/oci.c
> +++ b/lib/remotes/oci.c
> @@ -1461,19 +1461,6 @@ static void ocierofs_io_close(struct erofs_vfile *vfile)
> *(struct ocierofs_iostream **)vfile->payload = NULL;
> }
>
> -static int ocierofs_is_erofs_native_image(struct ocierofs_ctx *ctx)
> -{
> - if (ctx->layer_count > 0 && ctx->layers[0] &&
> - ctx->layers[0]->media_type) {
> - const char *media_type = ctx->layers[0]->media_type;
> - size_t len = strlen(media_type);
> -
> - if (len >= 6 && strcmp(media_type + len - 6, ".erofs") == 0)
> - return 0;
> - }
> - return -ENOENT;
> -}
> -
> static struct erofs_vfops ocierofs_io_vfops = {
> .pread = ocierofs_io_pread,
> .read = ocierofs_io_read,
> @@ -1497,13 +1484,6 @@ int ocierofs_io_open(struct erofs_vfile *vfile, const struct ocierofs_config *cf
> return err;
> }
>
> - err = ocierofs_is_erofs_native_image(ctx);
> - if (err) {
> - ocierofs_ctx_cleanup(ctx);
> - free(ctx);
> - return err;
> - }
> -
> oci_iostream = calloc(1, sizeof(*oci_iostream));
> if (!oci_iostream) {
> ocierofs_ctx_cleanup(ctx);
> diff --git a/mount/main.c b/mount/main.c
> index eb0dd01..619bf13 100644
> --- a/mount/main.c
> +++ b/mount/main.c
> @@ -16,6 +16,8 @@
> #include "erofs/io.h"
> #include "../lib/liberofs_nbd.h"
> #include "../lib/liberofs_oci.h"
> +#include "../lib/liberofs_gzran.h"
> +
> #ifdef HAVE_LINUX_LOOP_H
> #include <linux/loop.h>
> #else
> @@ -35,6 +37,9 @@ struct loop_info {
> #include <sys/sysmacros.h>
> #endif
>
> +/* Device boundary probe */
> +#define EROFS_IS_DEVICE_PROBE(off) ((off) >= (INT64_MAX >> 9))
I meant just add a macro
#define EROFSMOUNT_NBD_DISK_SIZE (INT64_MAX >> 9)
> +
> enum erofs_backend_drv {
> EROFSAUTO,
> EROFSLOCAL,
> @@ -141,7 +146,25 @@ static int erofsmount_parse_oci_option(const char *option)
> if (!oci_cfg->password)
> return -ENOMEM;
> } else {
> - return -EINVAL;
> + p = strstr(option, "oci.tarindex=");
> + if (p != NULL) {
> + p += strlen("oci.tarindex=");
> + free(oci_cfg->tarindex_path);
> + oci_cfg->tarindex_path = strdup(p);
> + if (!oci_cfg->tarindex_path)
> + return -ENOMEM;
> + } else {
> + p = strstr(option, "oci.zinfo=");
> + if (p != NULL) {
> + p += strlen("oci.zinfo=");
> + free(oci_cfg->zinfo_path);
> + oci_cfg->zinfo_path = strdup(p);
> + if (!oci_cfg->zinfo_path)
> + return -ENOMEM;
> + } else {
> + return -EINVAL;
> + }
> + }
> }
> }
> }
> @@ -332,11 +355,284 @@ static int erofsmount_fuse(const char *source, const char *mountpoint,
> return 0;
> }
>
> +struct erofsmount_tarindex_source {
> + struct erofs_vfile *tarindex_vf;
> + struct erofs_vfile *zinfo_vf;
> + u64 tarindex_size;
> +};
> +
> struct erofsmount_nbd_ctx {
> struct erofs_vfile vd; /* virtual device */
> struct erofs_vfile sk; /* socket file */
> };
>
> +static ssize_t erofs_tarindex_pread(struct erofs_vfile *vf, void *buf,
> + size_t count, u64 offset)
> +{
> + struct erofsmount_tarindex_source *hs;
> + ssize_t local_read, remote_read;
> + u64 local_part, remote_part, remote_offset;
index_part and tardata_part may be clearer.
> +
> + hs = *(struct erofsmount_tarindex_source **)vf->payload;
> + if (!hs)
> + return -EINVAL;
> +
> + /* Handle device boundary probe requests */
> + if (EROFS_IS_DEVICE_PROBE(offset))
> + return 0;
> +
> + if (offset >= hs->tarindex_size) {
> + remote_offset = offset - hs->tarindex_size;
> +
> + return hs->zinfo_vf->ops->pread(hs->zinfo_vf, buf, count, remote_offset);
> + }
> +
> + if (offset + count <= hs->tarindex_size)
> + return erofs_io_pread(hs->tarindex_vf, buf, count, offset);
> +
> + local_part = hs->tarindex_size - offset;
> + remote_part = count - local_part;
> +
> + local_read = erofs_io_pread(hs->tarindex_vf, buf, local_part, offset);
> + if (local_read < 0)
> + return local_read;
> +
> + remote_read = hs->zinfo_vf->ops->pread(hs->zinfo_vf,
> + (char *)buf + local_read,
> + remote_part, 0);
> + if (remote_read < 0)
> + return remote_read;
> + return local_read + remote_read;
> +}
> +
> +static void erofs_tarindex_close(struct erofs_vfile *vf)
> +{
> + struct erofsmount_tarindex_source *hs;
> +
> + if (!vf)
> + return;
> +
> + hs = *(struct erofsmount_tarindex_source **)vf->payload;
> + if (!hs)
> + return;
> +
> + if (hs->tarindex_size > 0) {
> + erofs_io_close(hs->tarindex_vf);
> + free(hs->tarindex_vf);
> + }
> +
> + if (hs->zinfo_vf)
> + erofs_io_close(hs->zinfo_vf);
> +
> + free(hs);
> +}
> +
> +static int load_file_to_buf(const char *path, void **out, unsigned int *out_len)
> +{
> + FILE *fp = NULL;
> + void *buf = NULL;
> + int ret = 0;
> + long sz;
> + size_t num;
> +
> + fp = fopen(path, "rb");
> + if (!fp)
> + return -errno;
> +
> + if (fseek(fp, 0, SEEK_END) != 0) {
> + ret = -errno;
> + goto out;
> + }
> + sz = ftell(fp);
> + if (sz < 0) {
> + ret = -errno;
> + goto out;
> + }
> + if (fseek(fp, 0, SEEK_SET) != 0) {
> + ret = -errno;
> + goto out;
> + }
> + if (sz == 0) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + buf = malloc((size_t)sz);
> + if (!buf) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + num = fread(buf, 1, (size_t)sz, fp);
> + if (num != (size_t)sz) {
> + ret = -EIO;
> + goto out;
> + }
> +
> + *out = buf;
> + *out_len = (unsigned int)sz;
> + buf = NULL;
> +
> +out:
> + if (fp)
> + fclose(fp);
> + if (ret < 0 && buf)
> + free(buf);
> + return ret;
> +}
> +
> +static int erofsmount_init_gzran(struct erofs_vfile **zinfo_vf,
> + const struct ocierofs_config *oci_cfg,
> + const char *zinfo_path)
> +{
> + int err = 0;
> + void *zinfo_data = NULL;
> + unsigned int zinfo_len = 0;
> + struct erofs_vfile *oci_vf = NULL;
> +
> + oci_vf = malloc(sizeof(*oci_vf));
> + if (!oci_vf) {
> + err = -ENOMEM;
> + goto cleanup;
> + }
> +
> + err = ocierofs_io_open(oci_vf, oci_cfg);
> + if (err) {
> + free(oci_vf);
> + goto cleanup;
> + }
> +
> + /* If no zinfo_path, return oci_vf directly for tar format */
> + if (!zinfo_path) {
> + *zinfo_vf = oci_vf;
> + return 0;
> + }
> +
> + err = load_file_to_buf(zinfo_path, &zinfo_data, &zinfo_len);
> + if (err) {
> + erofs_io_close(oci_vf);
> + free(oci_vf);
> + return err;
> + }
> +
> + *zinfo_vf = erofs_gzran_zinfo_open(oci_vf, zinfo_data, zinfo_len);
> + if (IS_ERR(*zinfo_vf)) {
> + err = PTR_ERR(*zinfo_vf);
> + *zinfo_vf = NULL;
> + erofs_io_close(oci_vf);
> + free(oci_vf);
> + goto cleanup;
> + }
> +
> + free(zinfo_data);
> + return 0;
> +
> +cleanup:
> + if (zinfo_data)
> + free(zinfo_data);
> + return err;
> +}
> +
> +static ssize_t erofs_tarindex_sendfile(struct erofs_vfile *vout, struct erofs_vfile *vin,
> + off_t *pos, size_t count)
> +{
> + static char buf[32768];
> + ssize_t total_written = 0, ret = 0, written;
> + size_t to_read;
> + u64 read_offset;
> +
> + while (count > 0) {
> + to_read = min_t(size_t, count, sizeof(buf));
> + read_offset = pos ? *pos : 0;
> +
> + ret = erofs_tarindex_pread(vin, buf, to_read, read_offset);
> + if (ret <= 0) {
> + if (ret < 0 && total_written == 0)
> + return ret;
> + break;
> + }
> +
> + written = __erofs_io_write(vout->fd, buf, ret);
> + if (written < 0) {
> + ret = -errno;
> + break;
> + }
> + if (written != ret)
> + ret = written;
> +
> + total_written += ret;
> + count -= ret;
> + if (pos)
> + *pos += ret;
> + }
> + return count;
> +}
> +
> +static struct erofs_vfops tarindex_vfile_ops = {
> + .pread = erofs_tarindex_pread,
> + .sendfile = erofs_tarindex_sendfile,
> + .close = erofs_tarindex_close,
> +};
> +
> +/*
> + * Create tarindex source for gzran+oci hybrid mode with three scenarios:
> + * 1. tarindex + zinfo: Remote data is tar.gzip format
> + * 2. tarindex only: Remote data is tar format
> + */
> +static int erofs_create_tarindex_source(struct erofs_vfile *out_vf,
> + const struct ocierofs_config *oci_cfg,
> + const char *tarindex_path,
> + const char *zinfo_path)
> +{
> + struct erofsmount_tarindex_source *hs;
> + int err;
> + struct stat st;
> +
> + hs = calloc(1, sizeof(*hs));
> + if (!hs)
> + return -ENOMEM;
> +
> + if (tarindex_path) {
> + hs->tarindex_vf = malloc(sizeof(*hs->tarindex_vf));
> + if (!hs->tarindex_vf) {
> + err = -ENOMEM;
> + goto cleanup;
> + }
> +
> + hs->tarindex_vf->fd = open(tarindex_path, O_RDONLY);
Let's avoid `hs->tarindex_vf->fd`.
I suggest using a local variable vf directly.
Otherwise it looks good to me.
Thanks,
Gao Xiang
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