LU-11417 llapi: add llapi_layout_get_by_xattr(3) API

[fs/lustre-release.git] / lustre / utils / liblustreapi_layout.c

diff --git a/lustre/utils/liblustreapi_layout.c b/lustre/utils/liblustreapi_layout.c
index f8b3ea6..f84b3b3 100644 (file)
--- a/lustre/utils/liblustreapi_layout.c
+++ b/lustre/utils/liblustreapi_layout.c
@@ -360,15 +360,16 @@ struct llapi_layout *llapi_layout_alloc(void)
  * Convert the data from a lov_user_md to a newly allocated llapi_layout.
  * The caller is responsible for freeing the returned pointer.
  *
- * \param[in] lum      LOV user metadata structure to copy data from
- * \param[in] lum_size size the the lum passed in
+ * \param[in] lov_xattr                LOV user metadata xattr to copy data from
+ * \param[in] lov_xattr_size   size the lov_xattr_size passed in
  *
  * \retval             valid llapi_layout pointer on success
  * \retval             NULL if memory allocation fails
  */
-static struct llapi_layout *
-llapi_layout_from_lum(const struct lov_user_md *lum, int lum_size)
+struct llapi_layout *llapi_layout_get_by_xattr(const void *lov_xattr,
+                                              ssize_t lov_xattr_size)
 {
+       const struct lov_user_md *lum = lov_xattr;
        struct lov_comp_md_v1 *comp_v1 = NULL;
        struct lov_comp_md_entry_v1 *ent;
        struct lov_user_md *v1;
@@ -392,6 +393,14 @@ llapi_layout_from_lum(const struct lov_user_md *lum, int lum_size)
                   lum->lmm_magic == LOV_MAGIC_V3) {
                ent_count = 1;
                layout->llot_is_composite = false;
+
+               if (lov_xattr_size <= 0) {
+                       errno = EINVAL;
+                       goto error;
+               }
+       } else {
+               errno = EOPNOTSUPP;
+               goto error;
        }
 
        if (ent_count == 0) {
@@ -405,12 +414,12 @@ llapi_layout_from_lum(const struct lov_user_md *lum, int lum_size)
                        ent = &comp_v1->lcm_entries[i];
                        v1 = (struct lov_user_md *)((char *)comp_v1 +
                                ent->lcme_offset);
-                       lum_size = ent->lcme_size;
+                       lov_xattr_size = ent->lcme_size;
                } else {
                        ent = NULL;
                }
 
-               obj_count = llapi_layout_objects_in_lum(v1, lum_size);
+               obj_count = llapi_layout_objects_in_lum(v1, lov_xattr_size);
                comp = __llapi_comp_alloc(obj_count);
                if (comp == NULL)
                        goto error;
@@ -884,7 +893,7 @@ struct llapi_layout *llapi_layout_get_by_fd(int fd, uint32_t flags)
                goto out;
        }
 
-       layout = llapi_layout_from_lum(lum, bytes_read);
+       layout = llapi_layout_get_by_xattr(lum, bytes_read);
 out:
        free(lum);
        return layout;