Merge tag 'ceph-for-4.19-rc3' of https://github.com/ceph/ceph-client

Pull ceph fixes from Ilya Dryomov:
 "Two rbd patches to complete support for images within namespaces that
  went into -rc1 and a use-after-free fix.

  The rbd changes have been sitting in a branch for quite a while but
  couldn't be included into the -rc1 pull request because of a pending
  wire protocol backwards compatibility fixup that only got committed
  early this week"

* tag 'ceph-for-4.19-rc3' of https://github.com/ceph/ceph-client:
  rbd: support cloning across namespaces
  rbd: factor out get_parent_info()
  ceph: avoid a use-after-free in ceph_destroy_options()

1 files changed, 178 insertions, 57 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 7915f3b03736..73ed5f3a862d 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4207,11 +4207,13 @@ static ssize_t rbd_parent_show(struct device *dev,
 
                 count += sprintf(&buf[count], "%s"
                             "pool_id %llu\npool_name %s\n"
+                            "pool_ns %s\n"
                             "image_id %s\nimage_name %s\n"
                             "snap_id %llu\nsnap_name %s\n"
                             "overlap %llu\n",
                             !count ? "" : "\n", /* first? */
                             spec->pool_id, spec->pool_name,
+                            spec->pool_ns ?: "",
                             spec->image_id, spec->image_name ?: "(unknown)",
                             spec->snap_id, spec->snap_name,
                             rbd_dev->parent_overlap);
@@ -4584,47 +4586,177 @@ static int rbd_dev_v2_features(struct rbd_device *rbd_dev)
                                                 &rbd_dev->header.features);
 }
 
+struct parent_image_info {
+        u64             pool_id;
+        const char      *pool_ns;
+        const char      *image_id;
+        u64             snap_id;
+
+        bool            has_overlap;
+        u64             overlap;
+};
+
+/*
+ * The caller is responsible for @pii.
+ */
+static int decode_parent_image_spec(void **p, void *end,
+                                    struct parent_image_info *pii)
+{
+        u8 struct_v;
+        u32 struct_len;
+        int ret;
+
+        ret = ceph_start_decoding(p, end, 1, "ParentImageSpec",
+                                  &struct_v, &struct_len);
+        if (ret)
+                return ret;
+
+        ceph_decode_64_safe(p, end, pii->pool_id, e_inval);
+        pii->pool_ns = ceph_extract_encoded_string(p, end, NULL, GFP_KERNEL);
+        if (IS_ERR(pii->pool_ns)) {
+                ret = PTR_ERR(pii->pool_ns);
+                pii->pool_ns = NULL;
+                return ret;
+        }
+        pii->image_id = ceph_extract_encoded_string(p, end, NULL, GFP_KERNEL);
+        if (IS_ERR(pii->image_id)) {
+                ret = PTR_ERR(pii->image_id);
+                pii->image_id = NULL;
+                return ret;
+        }
+        ceph_decode_64_safe(p, end, pii->snap_id, e_inval);
+        return 0;
+
+e_inval:
+        return -EINVAL;
+}
+
+static int __get_parent_info(struct rbd_device *rbd_dev,
+                             struct page *req_page,
+                             struct page *reply_page,
+                             struct parent_image_info *pii)
+{
+        struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
+        size_t reply_len = PAGE_SIZE;
+        void *p, *end;
+        int ret;
+
+        ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
+                             "rbd", "parent_get", CEPH_OSD_FLAG_READ,
+                             req_page, sizeof(u64), reply_page, &reply_len);
+        if (ret)
+                return ret == -EOPNOTSUPP ? 1 : ret;
+
+        p = page_address(reply_page);
+        end = p + reply_len;
+        ret = decode_parent_image_spec(&p, end, pii);
+        if (ret)
+                return ret;
+
+        ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
+                             "rbd", "parent_overlap_get", CEPH_OSD_FLAG_READ,
+                             req_page, sizeof(u64), reply_page, &reply_len);
+        if (ret)
+                return ret;
+
+        p = page_address(reply_page);
+        end = p + reply_len;
+        ceph_decode_8_safe(&p, end, pii->has_overlap, e_inval);
+        if (pii->has_overlap)
+                ceph_decode_64_safe(&p, end, pii->overlap, e_inval);
+
+        return 0;
+
+e_inval:
+        return -EINVAL;
+}
+
+/*
+ * The caller is responsible for @pii.
+ */
+static int __get_parent_info_legacy(struct rbd_device *rbd_dev,
+                                    struct page *req_page,
+                                    struct page *reply_page,
+                                    struct parent_image_info *pii)
+{
+        struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
+        size_t reply_len = PAGE_SIZE;
+        void *p, *end;
+        int ret;
+
+        ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
+                             "rbd", "get_parent", CEPH_OSD_FLAG_READ,
+                             req_page, sizeof(u64), reply_page, &reply_len);
+        if (ret)
+                return ret;
+
+        p = page_address(reply_page);
+        end = p + reply_len;
+        ceph_decode_64_safe(&p, end, pii->pool_id, e_inval);
+        pii->image_id = ceph_extract_encoded_string(&p, end, NULL, GFP_KERNEL);
+        if (IS_ERR(pii->image_id)) {
+                ret = PTR_ERR(pii->image_id);
+                pii->image_id = NULL;
+                return ret;
+        }
+        ceph_decode_64_safe(&p, end, pii->snap_id, e_inval);
+        pii->has_overlap = true;
+        ceph_decode_64_safe(&p, end, pii->overlap, e_inval);
+
+        return 0;
+
+e_inval:
+        return -EINVAL;
+}
+
+static int get_parent_info(struct rbd_device *rbd_dev,
+                           struct parent_image_info *pii)
+{
+        struct page *req_page, *reply_page;
+        void *p;
+        int ret;
+
+        req_page = alloc_page(GFP_KERNEL);
+        if (!req_page)
+                return -ENOMEM;
+
+        reply_page = alloc_page(GFP_KERNEL);
+        if (!reply_page) {
+                __free_page(req_page);
+                return -ENOMEM;
+        }
+
+        p = page_address(req_page);
+        ceph_encode_64(&p, rbd_dev->spec->snap_id);
+        ret = __get_parent_info(rbd_dev, req_page, reply_page, pii);
+        if (ret > 0)
+                ret = __get_parent_info_legacy(rbd_dev, req_page, reply_page,
+                                               pii);
+
+        __free_page(req_page);
+        __free_page(reply_page);
+        return ret;
+}
+
 static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
 {
         struct rbd_spec *parent_spec;
-        size_t size;
-        void *reply_buf = NULL;
-        __le64 snapid;
-        void *p;
-        void *end;
-        u64 pool_id;
-        char *image_id;
-        u64 snap_id;
-        u64 overlap;
+        struct parent_image_info pii = { 0 };
         int ret;
 
         parent_spec = rbd_spec_alloc();
         if (!parent_spec)
                 return -ENOMEM;
 
-        size = sizeof (__le64) +                                /* pool_id */
-                sizeof (__le32) + RBD_IMAGE_ID_LEN_MAX +        /* image_id */
-                sizeof (__le64) +                               /* snap_id */
-                sizeof (__le64);                                /* overlap */
-        reply_buf = kmalloc(size, GFP_KERNEL);
-        if (!reply_buf) {
-                ret = -ENOMEM;
+        ret = get_parent_info(rbd_dev, &pii);
+        if (ret)
                 goto out_err;
-        }
 
-        snapid = cpu_to_le64(rbd_dev->spec->snap_id);
-        ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
-                                  &rbd_dev->header_oloc, "get_parent",
-                                  &snapid, sizeof(snapid), reply_buf, size);
-        dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
-        if (ret < 0)
-                goto out_err;
+        dout("%s pool_id %llu pool_ns %s image_id %s snap_id %llu has_overlap %d overlap %llu\n",
+             __func__, pii.pool_id, pii.pool_ns, pii.image_id, pii.snap_id,
+             pii.has_overlap, pii.overlap);
 
-        p = reply_buf;
-        end = reply_buf + ret;
-        ret = -ERANGE;
-        ceph_decode_64_safe(&p, end, pool_id, out_err);
-        if (pool_id == CEPH_NOPOOL) {
+        if (pii.pool_id == CEPH_NOPOOL || !pii.has_overlap) {
                 /*
                  * Either the parent never existed, or we have
                  * record of it but the image got flattened so it no
@@ -4633,6 +4765,10 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
                  * overlap to 0.  The effect of this is that all new
                  * requests will be treated as if the image had no
                  * parent.
+                 *
+                 * If !pii.has_overlap, the parent image spec is not
+                 * applicable.  It's there to avoid duplication in each
+                 * snapshot record.
                  */
                 if (rbd_dev->parent_overlap) {
                         rbd_dev->parent_overlap = 0;
@@ -4647,51 +4783,36 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
         /* The ceph file layout needs to fit pool id in 32 bits */
 
         ret = -EIO;
-        if (pool_id > (u64)U32_MAX) {
+        if (pii.pool_id > (u64)U32_MAX) {
                 rbd_warn(NULL, "parent pool id too large (%llu > %u)",
-                        (unsigned long long)pool_id, U32_MAX);
+                        (unsigned long long)pii.pool_id, U32_MAX);
                 goto out_err;
         }
 
-        image_id = ceph_extract_encoded_string(&p, end, NULL, GFP_KERNEL);
-        if (IS_ERR(image_id)) {
-                ret = PTR_ERR(image_id);
-                goto out_err;
-        }
-        ceph_decode_64_safe(&p, end, snap_id, out_err);
-        ceph_decode_64_safe(&p, end, overlap, out_err);
-
         /*
          * The parent won't change (except when the clone is
          * flattened, already handled that).  So we only need to
          * record the parent spec we have not already done so.
          */
         if (!rbd_dev->parent_spec) {
-                parent_spec->pool_id = pool_id;
-                parent_spec->image_id = image_id;
-                parent_spec->snap_id = snap_id;
-
-                /* TODO: support cloning across namespaces */
-                if (rbd_dev->spec->pool_ns) {
-                        parent_spec->pool_ns = kstrdup(rbd_dev->spec->pool_ns,
-                                                       GFP_KERNEL);
-                        if (!parent_spec->pool_ns) {
-                                ret = -ENOMEM;
-                                goto out_err;
-                        }
+                parent_spec->pool_id = pii.pool_id;
+                if (pii.pool_ns && *pii.pool_ns) {
+                        parent_spec->pool_ns = pii.pool_ns;
+                        pii.pool_ns = NULL;
                 }
+                parent_spec->image_id = pii.image_id;
+                pii.image_id = NULL;
+                parent_spec->snap_id = pii.snap_id;
 
                 rbd_dev->parent_spec = parent_spec;
                 parent_spec = NULL;     /* rbd_dev now owns this */
-        } else {
-                kfree(image_id);
         }
 
         /*
          * We always update the parent overlap.  If it's zero we issue
          * a warning, as we will proceed as if there was no parent.
          */
-        if (!overlap) {
+        if (!pii.overlap) {
                 if (parent_spec) {
                         /* refresh, careful to warn just once */
                         if (rbd_dev->parent_overlap)
@@ -4702,14 +4823,14 @@ static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
                         rbd_warn(rbd_dev, "clone is standalone (overlap 0)");
                 }
         }
-        rbd_dev->parent_overlap = overlap;
+        rbd_dev->parent_overlap = pii.overlap;
 
 out:
         ret = 0;
 out_err:
-        kfree(reply_buf);
+        kfree(pii.pool_ns);
+        kfree(pii.image_id);
         rbd_spec_put(parent_spec);
-
         return ret;
 }