X-Git-Url: https://git.whamcloud.com/?a=blobdiff_plain;f=lustre%2Futils%2Fliblustreapi_layout.c;h=87ed8c875c56765a3b6121c27450c305ad280a25;hb=300858ccfcd00b52663de45e0bb472012242f342;hp=591946e62c0bb0a0ba7fe2272a0cd04809ebb4d1;hpb=632b3591b6ea21e3029299ef875179a4b5ca918f;p=fs%2Flustre-release.git

diff --git a/lustre/utils/liblustreapi_layout.c b/lustre/utils/liblustreapi_layout.c
index 591946e..87ed8c8 100644
--- a/lustre/utils/liblustreapi_layout.c
+++ b/lustre/utils/liblustreapi_layout.c
@@ -63,6 +63,7 @@ struct llapi_layout_comp {
 	uint64_t		llc_timestamp;	/* snapshot timestamp */
 	struct list_head	llc_list;	/* linked to the llapi_layout
 						   components list */
+	bool		llc_ondisk;
 };
 
 /**
@@ -134,11 +135,11 @@ llapi_layout_swab_lov_user_md(struct lov_user_md *lum, int lum_size)
 		comp_v1 = (struct lov_comp_md_v1 *)lum;
 
 	if (comp_v1 != NULL) {
-		__swab32s(&comp_v1->lcm_magic);
-		__swab32s(&comp_v1->lcm_size);
-		__swab32s(&comp_v1->lcm_layout_gen);
-		__swab16s(&comp_v1->lcm_flags);
-		__swab16s(&comp_v1->lcm_entry_count);
+		comp_v1->lcm_magic = __swab32(comp_v1->lcm_magic);
+		comp_v1->lcm_size = __swab32(comp_v1->lcm_size);
+		comp_v1->lcm_layout_gen = __swab32(comp_v1->lcm_layout_gen);
+		comp_v1->lcm_flags = __swab16(comp_v1->lcm_flags);
+		comp_v1->lcm_entry_count = __swab16(comp_v1->lcm_entry_count);
 		ent_count = comp_v1->lcm_entry_count;
 	} else {
 		ent_count = 1;
@@ -147,13 +148,13 @@ llapi_layout_swab_lov_user_md(struct lov_user_md *lum, int lum_size)
 	for (i = 0; i < ent_count; i++) {
 		if (comp_v1 != NULL) {
 			ent = &comp_v1->lcm_entries[i];
-			__swab32s(&ent->lcme_id);
-			__swab32s(&ent->lcme_flags);
-			__swab64s(&ent->lcme_timestamp);
-			__swab64s(&ent->lcme_extent.e_start);
-			__swab64s(&ent->lcme_extent.e_end);
-			__swab32s(&ent->lcme_offset);
-			__swab32s(&ent->lcme_size);
+			ent->lcme_id = __swab32(ent->lcme_id);
+			ent->lcme_flags = __swab32(ent->lcme_flags);
+			ent->lcme_timestamp = __swab64(ent->lcme_timestamp);
+			ent->lcme_extent.e_start = __swab64(ent->lcme_extent.e_start);
+			ent->lcme_extent.e_end = __swab64(ent->lcme_extent.e_end);
+			ent->lcme_offset = __swab32(ent->lcme_offset);
+			ent->lcme_size = __swab32(ent->lcme_size);
 
 			lum = (struct lov_user_md *)((char *)comp_v1 +
 					ent->lcme_offset);
@@ -161,11 +162,11 @@ llapi_layout_swab_lov_user_md(struct lov_user_md *lum, int lum_size)
 		}
 		obj_count = llapi_layout_objects_in_lum(lum, lum_size);
 
-		__swab32s(&lum->lmm_magic);
-		__swab32s(&lum->lmm_pattern);
-		__swab32s(&lum->lmm_stripe_size);
-		__swab16s(&lum->lmm_stripe_count);
-		__swab16s(&lum->lmm_stripe_offset);
+		lum->lmm_magic = __swab32(lum->lmm_magic);
+		lum->lmm_pattern = __swab32(lum->lmm_pattern);
+		lum->lmm_stripe_size = __swab32(lum->lmm_stripe_size);
+		lum->lmm_stripe_count = __swab16(lum->lmm_stripe_count);
+		lum->lmm_stripe_offset = __swab16(lum->lmm_stripe_offset);
 
 		if (lum->lmm_magic != LOV_MAGIC_V1) {
 			struct lov_user_md_v3 *v3;
@@ -176,7 +177,7 @@ llapi_layout_swab_lov_user_md(struct lov_user_md *lum, int lum_size)
 		}
 
 		for (j = 0; j < obj_count; j++)
-			__swab32s(&lod[j].l_ost_idx);
+			lod[j].l_ost_idx = __swab32(lod[j].l_ost_idx);
 	}
 }
 
@@ -357,29 +358,134 @@ struct llapi_layout *llapi_layout_alloc(void)
 }
 
 /**
+ * Check if the given \a lum_size is large enough to hold the required
+ * fields in \a lum.
+ *
+ * \param[in] lum	the struct lov_user_md to check
+ * \param[in] lum_size	the number of bytes in \a lum
+ *
+ * \retval true		the \a lum_size is too small
+ * \retval false	the \a lum_size is large enough
+ */
+static bool llapi_layout_lum_truncated(struct lov_user_md *lum, size_t lum_size)
+{
+	uint32_t magic;
+
+	if (lum_size < sizeof(lum->lmm_magic))
+		return true;
+
+	if (lum->lmm_magic == LOV_MAGIC_V1 ||
+	    lum->lmm_magic == __swab32(LOV_MAGIC_V1))
+		magic = LOV_MAGIC_V1;
+	else if (lum->lmm_magic == LOV_MAGIC_V3 ||
+		 lum->lmm_magic == __swab32(LOV_MAGIC_V3))
+		magic = LOV_MAGIC_V3;
+	else if (lum->lmm_magic == LOV_MAGIC_COMP_V1 ||
+		 lum->lmm_magic == __swab32(LOV_MAGIC_COMP_V1))
+		magic = LOV_MAGIC_COMP_V1;
+	else
+		return true;
+
+	if (magic == LOV_MAGIC_V1 || magic == LOV_MAGIC_V3)
+		return lum_size < lov_user_md_size(0, magic);
+	else
+		return lum_size < sizeof(struct lov_comp_md_v1);
+}
+
+/* Verify if the objects count in lum is consistent with the
+ * stripe count in lum. It applies to regular file only. */
+static bool llapi_layout_lum_valid(struct lov_user_md *lum, int lum_size)
+{
+	struct lov_comp_md_v1 *comp_v1 = NULL;
+	int i, ent_count, obj_count;
+
+	if (lum->lmm_magic == LOV_MAGIC_COMP_V1) {
+		comp_v1 = (struct lov_comp_md_v1 *)lum;
+		ent_count = comp_v1->lcm_entry_count;
+	} else if (lum->lmm_magic == LOV_MAGIC_V1 ||
+		   lum->lmm_magic == LOV_MAGIC_V3) {
+		ent_count = 1;
+	} else {
+		return false;
+	}
+
+	for (i = 0; i < ent_count; i++) {
+		if (comp_v1) {
+			lum = (struct lov_user_md *)((char *)comp_v1 +
+				comp_v1->lcm_entries[i].lcme_offset);
+			lum_size = comp_v1->lcm_entries[i].lcme_size;
+		}
+		obj_count = llapi_layout_objects_in_lum(lum, lum_size);
+
+		if (comp_v1) {
+			if (!(comp_v1->lcm_entries[i].lcme_flags &
+				 LCME_FL_INIT) && obj_count != 0)
+				return false;
+		} else if (obj_count != lum->lmm_stripe_count) {
+			return false;
+		}
+	}
+	return true;
+}
+
+/**
  * 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] lov_xattr		LOV user metadata xattr to copy data from
  * \param[in] lov_xattr_size	size the lov_xattr_size passed in
+ * \param[in] flags		bitwise-or'd flags to control the behavior
  *
  * \retval		valid llapi_layout pointer on success
  * \retval		NULL if memory allocation fails
  */
-struct llapi_layout *llapi_layout_get_by_xattr(const void *lov_xattr,
-					       ssize_t lov_xattr_size)
+struct llapi_layout *llapi_layout_get_by_xattr(void *lov_xattr,
+					       ssize_t lov_xattr_size,
+					       uint32_t flags)
 {
-	const struct lov_user_md *lum = lov_xattr;
+	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;
-	struct llapi_layout *layout;
+	struct llapi_layout *layout = NULL;
 	struct llapi_layout_comp *comp;
 	int i, ent_count = 0, obj_count;
 
-	layout = __llapi_layout_alloc();
-	if (layout == NULL)
+	if (lov_xattr == NULL || lov_xattr_size <= 0) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	/* Return an error if we got back a partial layout. */
+	if (llapi_layout_lum_truncated(lov_xattr, lov_xattr_size)) {
+		errno = ERANGE;
 		return NULL;
+	}
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+	if (flags & LLAPI_LXF_COPY) {
+		lum = malloc(lov_xattr_size);
+		if (lum == NULL) {
+			errno = ENOMEM;
+			return NULL;
+		}
+		memcpy(lum, lov_xattr, lov_xattr_size);
+	}
+#endif
+
+	llapi_layout_swab_lov_user_md(lum, lov_xattr_size);
+
+	if ((flags & LLAPI_LXF_CHECK) &&
+	    !llapi_layout_lum_valid(lum, lov_xattr_size)) {
+		errno = EBADSLT;
+		goto out;
+	}
+
+	layout = __llapi_layout_alloc();
+	if (layout == NULL) {
+		errno = ENOMEM;
+		goto out;
+	}
 
 	if (lum->lmm_magic == LOV_MAGIC_COMP_V1) {
 		comp_v1 = (struct lov_comp_md_v1 *)lum;
@@ -396,16 +502,16 @@ struct llapi_layout *llapi_layout_get_by_xattr(const void *lov_xattr,
 
 		if (lov_xattr_size <= 0) {
 			errno = EINVAL;
-			goto error;
+			goto out_layout;
 		}
 	} else {
 		errno = EOPNOTSUPP;
-		goto error;
+		goto out_layout;
 	}
 
 	if (ent_count == 0) {
 		errno = EINVAL;
-		goto error;
+		goto out_layout;
 	}
 
 	v1 = (struct lov_user_md *)lum;
@@ -422,7 +528,7 @@ struct llapi_layout *llapi_layout_get_by_xattr(const void *lov_xattr,
 		obj_count = llapi_layout_objects_in_lum(v1, lov_xattr_size);
 		comp = __llapi_comp_alloc(obj_count);
 		if (comp == NULL)
-			goto error;
+			goto out_layout;
 
 		if (ent != NULL) {
 			comp->llc_extent.e_start = ent->lcme_extent.e_start;
@@ -440,8 +546,15 @@ struct llapi_layout *llapi_layout_get_by_xattr(const void *lov_xattr,
 
 		if (v1->lmm_pattern == LOV_PATTERN_RAID0)
 			comp->llc_pattern = LLAPI_LAYOUT_RAID0;
+		else if (v1->lmm_pattern == (LOV_PATTERN_RAID0 |
+					 LOV_PATTERN_OVERSTRIPING))
+			comp->llc_pattern = LLAPI_LAYOUT_OVERSTRIPING;
+		else if (v1->lmm_pattern == LOV_PATTERN_MDT)
+			comp->llc_pattern = LLAPI_LAYOUT_MDT;
 		else
-			/* Lustre only supports RAID0 for now. */
+			/* Lustre only supports RAID0, overstripping
+			 * and DoM for now.
+			 */
 			comp->llc_pattern = v1->lmm_pattern;
 
 		if (v1->lmm_stripe_size == 0)
@@ -481,14 +594,43 @@ struct llapi_layout *llapi_layout_get_by_xattr(const void *lov_xattr,
 			comp->llc_stripe_offset =
 				comp->llc_objects[0].l_ost_idx;
 
+		comp->llc_ondisk = true;
 		list_add_tail(&comp->llc_list, &layout->llot_comp_list);
 		layout->llot_cur_comp = comp;
 	}
 
+out:
+	if (lum != lov_xattr)
+		free(lum);
 	return layout;
-error:
+out_layout:
 	llapi_layout_free(layout);
-	return NULL;
+	layout = NULL;
+	goto out;
+}
+
+__u32 llapi_pattern_to_lov(uint64_t pattern)
+{
+	__u32 lov_pattern;
+
+	switch (pattern) {
+	case LLAPI_LAYOUT_DEFAULT:
+		lov_pattern = LOV_PATTERN_RAID0;
+		break;
+	case LLAPI_LAYOUT_RAID0:
+		lov_pattern = LOV_PATTERN_RAID0;
+		break;
+	case LLAPI_LAYOUT_MDT:
+		lov_pattern = LOV_PATTERN_MDT;
+		break;
+	case LLAPI_LAYOUT_OVERSTRIPING:
+		lov_pattern = LOV_PATTERN_OVERSTRIPING | LOV_PATTERN_RAID0;
+		break;
+	default:
+		lov_pattern = EINVAL;
+	}
+
+	return lov_pattern;
 }
 
 /**
@@ -585,12 +727,11 @@ llapi_layout_to_lum(const struct llapi_layout *layout)
 		}
 
 		blob->lmm_magic = magic;
-		if (pattern == LLAPI_LAYOUT_DEFAULT)
-			blob->lmm_pattern = LOV_PATTERN_RAID0;
-		else if (pattern == LLAPI_LAYOUT_MDT)
-			blob->lmm_pattern = LOV_PATTERN_MDT;
-		else
-			blob->lmm_pattern = pattern;
+		blob->lmm_pattern = llapi_pattern_to_lov(pattern);
+		if (blob->lmm_pattern == EINVAL) {
+			errno = EINVAL;
+			goto error;
+		}
 
 		if (comp->llc_stripe_size == LLAPI_LAYOUT_DEFAULT)
 			blob->lmm_stripe_size = 0;
@@ -666,7 +807,7 @@ static void get_parent_dir(const char *path, char *buf, size_t size)
 {
 	char *p;
 
-	strncpy(buf, path, size);
+	strncpy(buf, path, size - 1);
 	p = strrchr(buf, '/');
 
 	if (p != NULL) {
@@ -764,77 +905,6 @@ static bool is_any_specified(const struct llapi_layout *layout)
 }
 
 /**
- * Check if the given \a lum_size is large enough to hold the required
- * fields in \a lum.
- *
- * \param[in] lum	the struct lov_user_md to check
- * \param[in] lum_size	the number of bytes in \a lum
- *
- * \retval true		the \a lum_size is too small
- * \retval false	the \a lum_size is large enough
- */
-static bool llapi_layout_lum_truncated(struct lov_user_md *lum, size_t lum_size)
-{
-	uint32_t magic;
-
-	if (lum_size < sizeof(lum->lmm_magic))
-		return true;
-
-	if (lum->lmm_magic == LOV_MAGIC_V1 ||
-	    lum->lmm_magic == __swab32(LOV_MAGIC_V1))
-		magic = LOV_MAGIC_V1;
-	else if (lum->lmm_magic == LOV_MAGIC_V3 ||
-		 lum->lmm_magic == __swab32(LOV_MAGIC_V3))
-		magic = LOV_MAGIC_V3;
-	else if (lum->lmm_magic == LOV_MAGIC_COMP_V1 ||
-		 lum->lmm_magic == __swab32(LOV_MAGIC_COMP_V1))
-		magic = LOV_MAGIC_COMP_V1;
-	else
-		return true;
-
-	if (magic == LOV_MAGIC_V1 || magic == LOV_MAGIC_V3)
-		return lum_size < lov_user_md_size(0, magic);
-	else
-		return lum_size < sizeof(struct lov_comp_md_v1);
-}
-
-/* Verify if the objects count in lum is consistent with the
- * stripe count in lum. It applies to regular file only. */
-static bool llapi_layout_lum_valid(struct lov_user_md *lum, int lum_size)
-{
-	struct lov_comp_md_v1 *comp_v1 = NULL;
-	int i, ent_count, obj_count;
-
-	if (lum->lmm_magic == LOV_MAGIC_COMP_V1) {
-		comp_v1 = (struct lov_comp_md_v1 *)lum;
-		ent_count = comp_v1->lcm_entry_count;
-	} else if (lum->lmm_magic == LOV_MAGIC_V1 ||
-		   lum->lmm_magic == LOV_MAGIC_V3) {
-		ent_count = 1;
-	} else {
-		return false;
-	}
-
-	for (i = 0; i < ent_count; i++) {
-		if (comp_v1) {
-			lum = (struct lov_user_md *)((char *)comp_v1 +
-				comp_v1->lcm_entries[i].lcme_offset);
-			lum_size = comp_v1->lcm_entries[i].lcme_size;
-		}
-		obj_count = llapi_layout_objects_in_lum(lum, lum_size);
-
-		if (comp_v1) {
-			if (!(comp_v1->lcm_entries[i].lcme_flags &
-				 LCME_FL_INIT) && obj_count != 0)
-				return false;
-		} else if (obj_count != lum->lmm_stripe_count) {
-			return false;
-		}
-	}
-	return true;
-}
-
-/**
  * Get the striping layout for the file referenced by file descriptor \a fd.
  *
  * If the filesystem does not support the "lustre." xattr namespace, the
@@ -873,14 +943,6 @@ struct llapi_layout *llapi_layout_get_by_fd(int fd, uint32_t flags)
 		goto out;
 	}
 
-	/* Return an error if we got back a partial layout. */
-	if (llapi_layout_lum_truncated(lum, bytes_read)) {
-		errno = EINTR;
-		goto out;
-	}
-
-	llapi_layout_swab_lov_user_md(lum, bytes_read);
-
 	/* Directories may have a positive non-zero lum->lmm_stripe_count
 	 * yet have an empty lum->lmm_objects array. For non-directories the
 	 * amount of data returned from the kernel must be consistent
@@ -888,12 +950,8 @@ struct llapi_layout *llapi_layout_get_by_fd(int fd, uint32_t flags)
 	if (fstat(fd, &st) < 0)
 		goto out;
 
-	if (!S_ISDIR(st.st_mode) && !llapi_layout_lum_valid(lum, bytes_read)) {
-		errno = EINTR;
-		goto out;
-	}
-
-	layout = llapi_layout_get_by_xattr(lum, bytes_read);
+	layout = llapi_layout_get_by_xattr(lum, bytes_read,
+		S_ISDIR(st.st_mode) ? 0 : LLAPI_LXF_CHECK);
 out:
 	free(lum);
 	return layout;
@@ -1100,6 +1158,13 @@ static bool llapi_layout_stripe_count_is_valid(int64_t stripe_count)
 		 llapi_stripe_count_is_valid(stripe_count));
 }
 
+static bool llapi_layout_extension_size_is_valid(uint64_t ext_size)
+{
+	return (ext_size != 0 &&
+		llapi_stripe_size_is_aligned(ext_size) &&
+		!llapi_stripe_size_is_too_big(ext_size));
+}
+
 static bool llapi_layout_stripe_size_is_valid(uint64_t stripe_size)
 {
 	return stripe_size == LLAPI_LAYOUT_DEFAULT ||
@@ -1144,18 +1209,20 @@ int llapi_layout_stripe_count_set(struct llapi_layout *layout,
 }
 
 /**
- * Get the stripe size of \a layout.
+ * Get the stripe/extension size of \a layout.
  *
  * \param[in] layout	layout to get stripe size from
  * \param[out] size	integer to store stripe size in
+ * \param[in] extension flag if extenion size is requested
  *
  * \retval	0 on success
  * \retval	-1 if arguments are invalid
  */
-int llapi_layout_stripe_size_get(const struct llapi_layout *layout,
-				 uint64_t *size)
+static int layout_stripe_size_get(const struct llapi_layout *layout,
+				  uint64_t *size, bool extension)
 {
 	struct llapi_layout_comp *comp;
+	int comp_ext;
 
 	comp = __llapi_layout_cur_comp(layout);
 	if (comp == NULL)
@@ -1166,39 +1233,82 @@ int llapi_layout_stripe_size_get(const struct llapi_layout *layout,
 		return -1;
 	}
 
+	comp_ext = comp->llc_flags & LCME_FL_EXTENSION;
+	if ((comp_ext && !extension) || (!comp_ext && extension)) {
+		errno = EINVAL;
+		return -1;
+	}
+
 	*size = comp->llc_stripe_size;
+	if (comp->llc_flags & LCME_FL_EXTENSION)
+		*size *= SEL_UNIT_SIZE;
 
 	return 0;
 }
 
+int llapi_layout_stripe_size_get(const struct llapi_layout *layout,
+				 uint64_t *size)
+{
+	return layout_stripe_size_get(layout, size, false);
+}
+
+int llapi_layout_extension_size_get(const struct llapi_layout *layout,
+				    uint64_t *size)
+{
+	return layout_stripe_size_get(layout, size, true);
+}
+
 /**
- * Set the stripe size of \a layout.
+ * Set the stripe/extension size of \a layout.
  *
  * \param[in] layout	layout to set stripe size in
  * \param[in] size	value to be set
+ * \param[in] extension flag if extenion size is passed
  *
  * \retval	0 on success
  * \retval	-1 if arguments are invalid
  */
-int llapi_layout_stripe_size_set(struct llapi_layout *layout,
-				 uint64_t size)
+static int layout_stripe_size_set(struct llapi_layout *layout,
+				  uint64_t size, bool extension)
 {
 	struct llapi_layout_comp *comp;
+	int comp_ext;
 
 	comp = __llapi_layout_cur_comp(layout);
 	if (comp == NULL)
 		return -1;
 
-	if (!llapi_layout_stripe_size_is_valid(size)) {
+	comp_ext = comp->llc_flags & LCME_FL_EXTENSION;
+	if ((comp_ext && !extension) || (!comp_ext && extension)) {
 		errno = EINVAL;
 		return -1;
 	}
 
-	comp->llc_stripe_size = size;
+	if (comp_ext)
+		size /= SEL_UNIT_SIZE;
+
+	if ((comp_ext && !llapi_layout_extension_size_is_valid(size)) ||
+	    (!comp_ext && !llapi_layout_stripe_size_is_valid(size))) {
+		errno = EINVAL;
+		return -1;
+	}
 
+	comp->llc_stripe_size = size;
 	return 0;
 }
 
+int llapi_layout_stripe_size_set(struct llapi_layout *layout,
+				 uint64_t size)
+{
+	return layout_stripe_size_set(layout, size, false);
+}
+
+int llapi_layout_extension_size_set(struct llapi_layout *layout,
+				    uint64_t size)
+{
+	return layout_stripe_size_set(layout, size, true);
+}
+
 /**
  * Get the RAID pattern of \a layout.
  *
@@ -1246,7 +1356,8 @@ int llapi_layout_pattern_set(struct llapi_layout *layout, uint64_t pattern)
 		return -1;
 
 	if (pattern != LLAPI_LAYOUT_DEFAULT &&
-	    pattern != LLAPI_LAYOUT_RAID0 && pattern != LLAPI_LAYOUT_MDT) {
+	    pattern != LLAPI_LAYOUT_RAID0 && pattern != LLAPI_LAYOUT_MDT
+	    && pattern != LLAPI_LAYOUT_OVERSTRIPING) {
 		errno = EOPNOTSUPP;
 		return -1;
 	}
@@ -1467,6 +1578,15 @@ int llapi_layout_file_open(const char *path, int open_flags, mode_t mode,
 		return -1;
 	}
 
+	if (layout) {
+		rc = llapi_layout_sanity((struct llapi_layout *)layout, false,
+					 !!(layout->llot_mirror_count > 1));
+		if (rc) {
+			llapi_layout_sanity_perror(rc);
+			return -1;
+		}
+	}
+
 	/* Object creation must be postponed until after layout attributes
 	 * have been applied. */
 	if (layout != NULL && (open_flags & O_CREAT))
@@ -1684,40 +1804,17 @@ int llapi_layout_comp_extent_get(const struct llapi_layout *layout,
 int llapi_layout_comp_extent_set(struct llapi_layout *layout,
 				 uint64_t start, uint64_t end)
 {
-	struct llapi_layout_comp *prev, *next, *comp;
+	struct llapi_layout_comp *comp;
 
 	comp = __llapi_layout_cur_comp(layout);
 	if (comp == NULL)
 		return -1;
 
-	if (start >= end) {
+	if (start > end) {
 		errno = EINVAL;
 		return -1;
 	}
 
-	/*
-	 * We need to make sure the extent to be set is valid: the new
-	 * extent must be adjacent with the prev & next component.
-	 */
-	if (comp->llc_list.prev != &layout->llot_comp_list) {
-		prev = list_entry(comp->llc_list.prev, typeof(*prev),
-				  llc_list);
-		if (start != 0 && start != prev->llc_extent.e_end) {
-			errno = EINVAL;
-			return -1;
-		}
-	}
-
-	if (comp->llc_list.next != &layout->llot_comp_list) {
-		next = list_entry(comp->llc_list.next, typeof(*next),
-				  llc_list);
-		if (next->llc_extent.e_start != 0 &&
-		    end != next->llc_extent.e_start) {
-			errno = EINVAL;
-			return -1;
-		}
-	}
-
 	comp->llc_extent.e_start = start;
 	comp->llc_extent.e_end = end;
 	layout->llot_is_composite = true;
@@ -1866,6 +1963,7 @@ int llapi_layout_mirror_id_get(const struct llapi_layout *layout, uint32_t *id)
 int llapi_layout_comp_add(struct llapi_layout *layout)
 {
 	struct llapi_layout_comp *last, *comp, *new;
+	bool composite = layout->llot_is_composite;
 
 	comp = __llapi_layout_cur_comp(layout);
 	if (comp == NULL)
@@ -1878,16 +1976,23 @@ int llapi_layout_comp_add(struct llapi_layout *layout)
 	last = list_entry(layout->llot_comp_list.prev, typeof(*last),
 			  llc_list);
 
-	if (new->llc_extent.e_end <= last->llc_extent.e_end) {
-		__llapi_comp_free(new);
-		errno = EINVAL;
-		return -1;
-	}
-	new->llc_extent.e_start = last->llc_extent.e_end;
-
 	list_add_tail(&new->llc_list, &layout->llot_comp_list);
-	layout->llot_cur_comp = new;
+
+	/* We must mark the layout composite for the sanity check, but it may
+	 * not stay that way if the check fails */
 	layout->llot_is_composite = true;
+	layout->llot_cur_comp = new;
+
+	/* We need to set a temporary non-zero value for "end" when we call
+	 * comp_extent_set, so we use LUSTRE_EOF-1, which is > all allowed
+	 * for the end of the previous component.  (If we're adding this
+	 * component, the end of the previous component cannot be EOF.) */
+	if (llapi_layout_comp_extent_set(layout, last->llc_extent.e_end,
+					LUSTRE_EOF - 1)) {
+		llapi_layout_comp_del(layout);
+		layout->llot_is_composite = composite;
+		return -1;
+	}
 
 	return 0;
 }
@@ -1952,14 +2057,11 @@ int llapi_layout_comp_del(struct llapi_layout *layout)
 		errno = EINVAL;
 		return -1;
 	}
-	/* It can't be the only one on the list */
-	if (comp->llc_list.prev == &layout->llot_comp_list) {
-		errno = EINVAL;
-		return -1;
-	}
-
 	layout->llot_cur_comp =
 		list_entry(comp->llc_list.prev, typeof(*comp), llc_list);
+	if (comp->llc_list.prev == &layout->llot_comp_list)
+		layout->llot_cur_comp = NULL;
+
 	list_del_init(&comp->llc_list);
 	__llapi_comp_free(comp);
 
@@ -2077,8 +2179,9 @@ int llapi_layout_comp_use(struct llapi_layout *layout,
 int llapi_layout_file_comp_add(const char *path,
 			       const struct llapi_layout *layout)
 {
-	int rc, fd, lum_size, tmp_errno = 0;
-	struct lov_user_md *lum;
+	int rc, fd = -1, lum_size, tmp_errno = 0;
+	struct llapi_layout *existing_layout = NULL;
+	struct lov_user_md *lum = NULL;
 
 	if (path == NULL || layout == NULL ||
 	    layout->llot_magic != LLAPI_LAYOUT_MAGIC) {
@@ -2086,34 +2189,60 @@ int llapi_layout_file_comp_add(const char *path,
 		return -1;
 	}
 
-	lum = llapi_layout_to_lum(layout);
-	if (lum == NULL)
-		return -1;
+	fd = open(path, O_RDWR);
+	if (fd < 0) {
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
+	}
 
-	if (lum->lmm_magic != LOV_USER_MAGIC_COMP_V1) {
-		free(lum);
-		errno = EINVAL;
-		return -1;
+	existing_layout = llapi_layout_get_by_fd(fd, 0);
+	if (existing_layout == NULL) {
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
 	}
-	lum_size = ((struct lov_comp_md_v1 *)lum)->lcm_size;
 
-	fd = open(path, O_RDWR);
-	if (fd < 0) {
+	rc = llapi_layout_merge(&existing_layout, layout);
+	if (rc) {
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
+	}
+
+	rc = llapi_layout_sanity(existing_layout, false, false);
+	if (rc) {
+		tmp_errno = errno;
+		llapi_layout_sanity_perror(rc);
+		rc = -1;
+		goto out;
+	}
+
+	lum = llapi_layout_to_lum(layout);
+	if (lum == NULL) {
 		tmp_errno = errno;
 		rc = -1;
 		goto out;
 	}
 
+	if (lum->lmm_magic != LOV_USER_MAGIC_COMP_V1) {
+		tmp_errno = EINVAL;
+		rc = -1;
+		goto out;
+	}
+	lum_size = ((struct lov_comp_md_v1 *)lum)->lcm_size;
+
 	rc = fsetxattr(fd, XATTR_LUSTRE_LOV".add", lum, lum_size, 0);
 	if (rc < 0) {
 		tmp_errno = errno;
-		close(fd);
 		rc = -1;
 		goto out;
 	}
-	close(fd);
 out:
+	if (fd >= 0)
+		close(fd);
 	free(lum);
+	llapi_layout_free(existing_layout);
 	errno = tmp_errno;
 	return rc;
 }
@@ -2129,18 +2258,20 @@ out:
  */
 int llapi_layout_file_comp_del(const char *path, uint32_t id, uint32_t flags)
 {
-	int rc, fd, lum_size;
+	int rc = 0, fd = -1, lum_size, tmp_errno = 0;
 	struct llapi_layout *layout;
-	struct llapi_layout_comp *comp;
-	struct lov_user_md *lum;
+	struct llapi_layout_comp *comp, *next;
+	struct llapi_layout *existing_layout = NULL;
+	struct lov_user_md *lum = NULL;
 
 	if (path == NULL || id > LCME_ID_MAX || (flags & ~LCME_KNOWN_FLAGS)) {
 		errno = EINVAL;
 		return -1;
 	}
 
-	/* Can only specify ID or flags, not both. */
-	if (id != 0 && flags != 0) {
+	/* Can only specify ID or flags, not both, not none. */
+	if ((id != LCME_ID_INVAL && flags != 0) ||
+	    (id == LCME_ID_INVAL && flags == 0)) {
 		errno = EINVAL;
 		return -1;
 	}
@@ -2152,8 +2283,9 @@ int llapi_layout_file_comp_del(const char *path, uint32_t id, uint32_t flags)
 	llapi_layout_comp_extent_set(layout, 0, LUSTRE_EOF);
 	comp = __llapi_layout_cur_comp(layout);
 	if (comp == NULL) {
-		llapi_layout_free(layout);
-		return -1;
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
 	}
 
 	comp->llc_id = id;
@@ -2161,38 +2293,155 @@ int llapi_layout_file_comp_del(const char *path, uint32_t id, uint32_t flags)
 
 	lum = llapi_layout_to_lum(layout);
 	if (lum == NULL) {
-		llapi_layout_free(layout);
-		return -1;
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
 	}
 	lum_size = ((struct lov_comp_md_v1 *)lum)->lcm_size;
 
 	fd = open(path, O_RDWR);
 	if (fd < 0) {
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
+	}
+
+	existing_layout = llapi_layout_get_by_fd(fd, 0);
+	if (existing_layout == NULL) {
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
+	}
+
+	comp = NULL;
+	next = NULL;
+	while (rc == 0 && existing_layout->llot_cur_comp != NULL) {
+		rc = llapi_layout_comp_use(existing_layout, comp ?
+					   LLAPI_LAYOUT_COMP_USE_PREV :
+					   LLAPI_LAYOUT_COMP_USE_LAST);
+		if (rc != 0)
+			break;
+
+		next = comp;
+		comp = __llapi_layout_cur_comp(existing_layout);
+		if (comp == NULL) {
+			rc = -1;
+			break;
+		}
+
+		if (id != LCME_ID_INVAL && id != comp->llc_id)
+			continue;
+		else if ((flags & LCME_FL_NEG) && (flags & comp->llc_flags))
+			continue;
+		else if (flags && !(flags & comp->llc_flags))
+			continue;
+
+		rc = llapi_layout_comp_del(existing_layout);
+		/* the layout position is moved to previous one, adjust */
+		comp = next;
+	}
+	if (rc < 0) {
+		tmp_errno = errno;
+		goto out;
+	}
+
+	rc = llapi_layout_sanity(existing_layout, false, false);
+	if (rc) {
+		tmp_errno = errno;
+		llapi_layout_sanity_perror(rc);
 		rc = -1;
 		goto out;
 	}
 
 	rc = fsetxattr(fd, XATTR_LUSTRE_LOV".del", lum, lum_size, 0);
 	if (rc < 0) {
-		int tmp_errno = errno;
-		close(fd);
-		errno = tmp_errno;
+		tmp_errno = errno;
 		rc = -1;
 		goto out;
 	}
-	close(fd);
+
 out:
+	if (fd >= 0)
+		close(fd);
 	free(lum);
 	llapi_layout_free(layout);
+	llapi_layout_free(existing_layout);
+	errno = tmp_errno;
+
 	return rc;
 }
 
+/* Internal utility function to apply flags for sanity checking */
+static void llapi_layout_comp_apply_flags(struct llapi_layout_comp *comp,
+					  uint32_t flags)
+{
+	if (flags & LCME_FL_NEG)
+		comp->llc_flags &= ~flags;
+	else
+		comp->llc_flags |= flags;
+}
+
+struct llapi_layout_apply_flags_args {
+	uint32_t *lfa_ids;
+	uint32_t *lfa_flags;
+	int lfa_count;
+	int lfa_rc;
+};
+
+
+static int llapi_layout_apply_flags_cb(struct llapi_layout *layout,
+				       void *arg)
+{
+	struct llapi_layout_apply_flags_args *args = arg;
+	struct llapi_layout_comp *comp;
+	int i = 0;
+
+	comp = __llapi_layout_cur_comp(layout);
+	if (comp == NULL) {
+		args->lfa_rc = -1;
+		return LLAPI_LAYOUT_ITER_STOP;
+	}
+
+	for (i = 0; i < args->lfa_count; i++) {
+		if (comp->llc_id == args->lfa_ids[i])
+			llapi_layout_comp_apply_flags(comp, args->lfa_flags[i]);
+	}
+
+	return LLAPI_LAYOUT_ITER_CONT;
+}
+
+/* Apply flags to the layout for sanity checking */
+static int llapi_layout_apply_flags(struct llapi_layout *layout, uint32_t *ids,
+				    uint32_t *flags, int count)
+{
+	struct llapi_layout_apply_flags_args args;
+	int rc = 0;
+
+	if (!ids || !flags || count == 0) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	args.lfa_ids = ids;
+	args.lfa_flags = flags;
+	args.lfa_count = count;
+	args.lfa_rc = 0;
+
+	rc = llapi_layout_comp_iterate(layout,
+				       llapi_layout_apply_flags_cb,
+				       &args);
+	if (errno == ENOENT)
+		errno = 0;
+
+	if (rc != LLAPI_LAYOUT_ITER_CONT)
+		rc = args.lfa_rc;
+
+	return rc;
+}
 /**
- * Change flags or other parameters of the component(s) by component ID of an
- * existing file. The component to be modified is specified by the
- * comp->lcme_id value, which must be an unique component ID. The new
- * attributes are passed in by @comp and @valid is used to specify which
- * attributes in the component are going to be changed.
+ * Change flags by component ID of components of an existing file.
+ * The component to be modified is specified by the comp->lcme_id value,
+ * which must be a unique component ID.
  *
  * \param[in] path	path name of the file
  * \param[in] ids	An array of component IDs
@@ -2203,9 +2452,10 @@ out:
 int llapi_layout_file_comp_set(const char *path, uint32_t *ids, uint32_t *flags,
 			       size_t count)
 {
-	int rc = -1, fd = -1, i;
+	int rc = -1, fd = -1, i, tmp_errno = 0;
 	size_t lum_size;
-	struct llapi_layout *layout;
+	struct llapi_layout *existing_layout = NULL;
+	struct llapi_layout *layout = NULL;
 	struct llapi_layout_comp *comp;
 	struct lov_user_md *lum = NULL;
 
@@ -2235,15 +2485,49 @@ int llapi_layout_file_comp_set(const char *path, uint32_t *ids, uint32_t *flags,
 		}
 	}
 
+	fd = open(path, O_RDWR);
+	if (fd < 0) {
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
+	}
+
+	existing_layout = llapi_layout_get_by_fd(fd, 0);
+	if (existing_layout == NULL) {
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
+	}
+
+	if (llapi_layout_apply_flags(existing_layout, ids, flags, count)) {
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
+	}
+
+	rc = llapi_layout_sanity(existing_layout, false, false);
+	if (rc) {
+		tmp_errno = errno;
+		llapi_layout_sanity_perror(rc);
+		rc = -1;
+		goto out;
+	}
+
 	layout = __llapi_layout_alloc();
-	if (layout == NULL)
-		return -1;
+	if (layout == NULL) {
+		tmp_errno = errno;
+		rc = -1;
+		goto out;
+	}
 
 	layout->llot_is_composite = true;
 	for (i = 0; i < count; i++) {
 		comp = __llapi_comp_alloc(0);
-		if (comp == NULL)
+		if (comp == NULL) {
+			tmp_errno = errno;
+			rc = -1;
 			goto out;
+		}
 
 		comp->llc_id = ids[i];
 		comp->llc_flags = flags[i];
@@ -2253,39 +2537,38 @@ int llapi_layout_file_comp_set(const char *path, uint32_t *ids, uint32_t *flags,
 	}
 
 	lum = llapi_layout_to_lum(layout);
-	if (lum == NULL)
+	if (lum == NULL) {
+		tmp_errno = errno;
+		rc = -1;
 		goto out;
+	}
 
 	lum_size = ((struct lov_comp_md_v1 *)lum)->lcm_size;
 
-	fd = open(path, O_RDWR);
-	if (fd < 0)
-		goto out;
-
 	/* flush cached pages from clients */
 	rc = llapi_file_flush(fd);
 	if (rc) {
-		errno = -rc;
+		tmp_errno = -rc;
 		rc = -1;
-		goto out_close;
+		goto out;
 	}
 
 	rc = fsetxattr(fd, XATTR_LUSTRE_LOV".set.flags", lum, lum_size, 0);
-	if (rc < 0)
-		goto out_close;
+	if (rc < 0) {
+		tmp_errno = errno;
+		goto out;
+	}
 
 	rc = 0;
 
-out_close:
-	if (fd >= 0) {
-		int tmp_errno = errno;
-		close(fd);
-		errno = tmp_errno;
-	}
 out:
-	if (lum)
-		free(lum);
+	if (fd >= 0)
+		close(fd);
+
+	free(lum);
+	llapi_layout_free(existing_layout);
 	llapi_layout_free(layout);
+	errno = tmp_errno;
 	return rc;
 }
 
@@ -2419,6 +2702,71 @@ error:
 }
 
 /**
+ * Get the last initialized component
+ *
+ * \param[in] layout	component layout list.
+ *
+ * \retval 0		found
+ * \retval -EINVAL	not found
+ * \retval -EISDIR	directory layout
+ */
+int llapi_layout_get_last_init_comp(struct llapi_layout *layout)
+{
+	struct llapi_layout_comp *comp = NULL, *head = NULL;
+
+	if (!layout->llot_is_composite)
+		return 0;
+
+	head = list_entry(layout->llot_comp_list.next, typeof(*comp), llc_list);
+	if (head == NULL)
+		return -EINVAL;
+	if (head->llc_id == 0 && !(head->llc_flags & LCME_FL_INIT))
+		/* a directory */
+		return -EISDIR;
+
+	/* traverse the components from the tail to find the last init one */
+	comp = list_entry(layout->llot_comp_list.prev, typeof(*comp), llc_list);
+	while (comp != head) {
+		if (comp->llc_flags & LCME_FL_INIT)
+			break;
+		comp = list_entry(comp->llc_list.prev, typeof(*comp), llc_list);
+	}
+
+	layout->llot_cur_comp = comp;
+
+	return comp->llc_flags & LCME_FL_INIT ? 0 : -EINVAL;
+}
+
+/**
+ * Interit stripe info from the file's component to the mirror
+ *
+ * \param[in] layout	file component layout list.
+ * \param[in] layout	mirro component layout list.
+ *
+ * \retval 0		on success
+ * \retval -EINVAL	on error
+ */
+int llapi_layout_mirror_inherit(struct llapi_layout *f_layout,
+				struct llapi_layout *m_layout)
+{
+	struct llapi_layout_comp *m_comp = NULL;
+	struct llapi_layout_comp *f_comp = NULL;
+	int rc = 0;
+
+	f_comp = __llapi_layout_cur_comp(f_layout);
+	if (f_comp == NULL)
+		return -EINVAL;
+	m_comp = __llapi_layout_cur_comp(m_layout);
+	if (m_comp == NULL)
+		return -EINVAL;
+
+	m_comp->llc_stripe_size = f_comp->llc_stripe_size;
+	m_comp->llc_stripe_count = f_comp->llc_stripe_count;
+
+	return rc;
+}
+
+/**
  * Find all stale components.
  *
  * \param[in] layout		component layout list.
@@ -2576,6 +2924,7 @@ int llapi_mirror_resync_many(int fd, struct llapi_layout *layout,
 	uint64_t pos = start;
 	int i;
 	int rc;
+	int rc2 = 0;
 
 	rc = posix_memalign(&buf, page_size, buflen);
 	if (rc)
@@ -2654,6 +3003,11 @@ int llapi_mirror_resync_many(int fd, struct llapi_layout *layout,
 				 * meanings.
 				 */
 				comp_array[i].lrc_synced = true;
+				llapi_error(LLAPI_MSG_ERROR, written,
+					    "component %u not synced",
+					    comp_array[i].lrc_id);
+				if (rc2 == 0)
+					rc2 = (int)written;
 				continue;
 			}
 			assert(written == to_write2);
@@ -2666,11 +3020,17 @@ int llapi_mirror_resync_many(int fd, struct llapi_layout *layout,
 	free(buf);
 
 	if (rc < 0) {
+		/* fatal error happens */
 		for (i = 0; i < comp_size; i++)
 			comp_array[i].lrc_synced = false;
 		return rc;
 	}
 
+	/**
+	 * no fatal error happens, each lrc_synced tells whether the component
+	 * has been resync successfully (note: we'd reverse the value to
+	 * reflect its true meaning.
+	 */
 	for (i = 0; i < comp_size; i++) {
 		comp_array[i].lrc_synced = !comp_array[i].lrc_synced;
 		if (comp_array[i].lrc_synced && pos & (page_size - 1)) {
@@ -2681,6 +3041,466 @@ int llapi_mirror_resync_many(int fd, struct llapi_layout *layout,
 		}
 	}
 
-	/* partially successful is successful */
+	/**
+	 * returns the first error code for partially successful resync if
+	 * possible.
+	 */
+	return rc2;
+}
+
+enum llapi_layout_comp_sanity_error {
+	LSE_OK,
+	LSE_INCOMPLETE_MIRROR,
+	LSE_ADJACENT_EXTENSION,
+	LSE_INIT_EXTENSION,
+	LSE_FLAGS,
+	LSE_DOM_EXTENSION,
+	LSE_DOM_EXTENSION_FOLLOWING,
+	LSE_DOM_FIRST,
+	LSE_SET_COMP_START,
+	LSE_NOT_ZERO_LENGTH_EXTENDABLE,
+	LSE_END_NOT_GREATER,
+	LSE_ZERO_LENGTH_NORMAL,
+	LSE_NOT_ADJACENT_PREV,
+	LSE_START_GT_END,
+	LSE_ALIGN_END,
+	LSE_ALIGN_EXT,
+	LSE_LAST,
+};
+
+const char *llapi_layout_strerror[] =
+{
+	[LSE_OK] = "",
+	[LSE_INCOMPLETE_MIRROR] =
+		"Incomplete mirror - must go to EOF",
+	[LSE_ADJACENT_EXTENSION] =
+		"No adjacent extension space components",
+	[LSE_INIT_EXTENSION] =
+		"Cannot apply extension flag to init components",
+	[LSE_FLAGS] =
+		"Wrong flags",
+	[LSE_DOM_EXTENSION] =
+		"DoM components can't be extension space",
+	[LSE_DOM_EXTENSION_FOLLOWING] =
+		"DoM components cannot be followed by extension space",
+	[LSE_DOM_FIRST] =
+		"DoM component should be the first one in a file/mirror",
+	[LSE_SET_COMP_START] =
+		"Must set previous component extent before adding next",
+	[LSE_NOT_ZERO_LENGTH_EXTENDABLE] =
+		"Extendable component must start out zero-length",
+	[LSE_END_NOT_GREATER] =
+		"Component end is before end of previous component",
+	[LSE_ZERO_LENGTH_NORMAL] =
+		"Zero length components must be followed by extension",
+	[LSE_NOT_ADJACENT_PREV] =
+		"Components not adjacent (end != next->start",
+	[LSE_START_GT_END] =
+		"Component start is > end",
+	[LSE_ALIGN_END] =
+		"The component end must be aligned by the stripe size",
+	[LSE_ALIGN_EXT] =
+		"The extension size must be aligned by the stripe size",
+};
+
+struct llapi_layout_sanity_args {
+	bool lsa_incomplete;
+	bool lsa_flr;
+	bool lsa_ondisk;
+	int lsa_rc;
+};
+
+/* The component flags can be set by users at creation/modification time. */
+#define LCME_USER_COMP_FLAGS	(LCME_FL_PREF_RW | LCME_FL_NOSYNC | \
+				 LCME_FL_EXTENSION)
+
+static int llapi_layout_sanity_cb(struct llapi_layout *layout,
+				  void *arg)
+{
+	struct llapi_layout_comp *comp, *next, *prev;
+	struct llapi_layout_sanity_args *args = arg;
+	bool first_comp = false;
+
+	comp = __llapi_layout_cur_comp(layout);
+	if (comp == NULL) {
+		args->lsa_rc = -1;
+		goto out_err;
+	}
+
+	if (comp->llc_list.prev != &layout->llot_comp_list)
+		prev = list_entry(comp->llc_list.prev, typeof(*prev),
+				  llc_list);
+	else
+		prev = NULL;
+
+	if (comp->llc_list.next != &layout->llot_comp_list)
+		next = list_entry(comp->llc_list.next, typeof(*next),
+				  llc_list);
+	else
+		next = NULL;
+
+	/* Start of zero implies a new mirror */
+	if (comp->llc_extent.e_start == 0) {
+		first_comp = true;
+		/* Most checks apply only within one mirror, this is an
+		 * exception. */
+		if (prev && prev->llc_extent.e_end != LUSTRE_EOF) {
+			args->lsa_rc = LSE_INCOMPLETE_MIRROR;
+			goto out_err;
+		}
+
+		prev = NULL;
+	}
+
+	if (next && next->llc_extent.e_start == 0)
+		next = NULL;
+
+	/* Flag sanity checks */
+	/* No adjacent extension components */
+	if ((comp->llc_flags & LCME_FL_EXTENSION) && next &&
+	    (next->llc_flags & LCME_FL_EXTENSION)) {
+		args->lsa_rc = LSE_ADJACENT_EXTENSION;
+		goto out_err;
+	}
+
+	/* Extension flag cannot be applied to init components and the first
+	 * component of each mirror is automatically init */
+	if ((comp->llc_flags & LCME_FL_EXTENSION) &&
+	    (comp->llc_flags & LCME_FL_INIT || first_comp)) {
+		args->lsa_rc = LSE_INIT_EXTENSION;
+		goto out_err;
+	}
+
+	if (comp->llc_ondisk) {
+		if (comp->llc_flags & LCME_FL_NEG)
+			args->lsa_rc = LSE_FLAGS;
+	} else if (!args->lsa_incomplete) {
+		if (args->lsa_flr) {
+			if (comp->llc_flags & ~LCME_USER_COMP_FLAGS)
+				args->lsa_rc = LSE_FLAGS;
+		} else {
+			if (comp->llc_flags & ~LCME_FL_EXTENSION)
+				args->lsa_rc = LSE_FLAGS;
+		}
+	}
+	if (args->lsa_rc)
+		goto out_err;
+
+	/* DoM sanity checks */
+	if (comp->llc_pattern == LLAPI_LAYOUT_MDT ||
+	    comp->llc_pattern == LOV_PATTERN_MDT) {
+		/* DoM components can't be extension components */
+		if (comp->llc_flags & LCME_FL_EXTENSION) {
+			args->lsa_rc = LSE_DOM_EXTENSION;
+			goto out_err;
+		}
+		/* DoM components cannot be followed by an extension comp */
+		if (next && (next->llc_flags & LCME_FL_EXTENSION)) {
+			args->lsa_rc = LSE_DOM_EXTENSION_FOLLOWING;
+			goto out_err;
+		}
+
+		/* DoM should be the first component in a mirror */
+		if (!first_comp) {
+			args->lsa_rc = LSE_DOM_FIRST;
+			errno = EINVAL;
+			goto out_err;
+		}
+	}
+
+	/* Extent sanity checks */
+	/* Must set previous component extent before adding another */
+	if (prev && prev->llc_extent.e_start == 0 &&
+	    prev->llc_extent.e_end == 0) {
+		args->lsa_rc = LSE_SET_COMP_START;
+		goto out_err;
+	}
+
+	if (!args->lsa_incomplete) {
+		/* Components followed by extension space (extendable
+		 * components) must be zero length before initialization.
+		 * (Except for first comp, which will be initialized on
+		 * creation). */
+		if (next && (next->llc_flags & LCME_FL_EXTENSION) &&
+		    !first_comp && !(comp->llc_flags & LCME_FL_INIT) &&
+		    comp->llc_extent.e_start != comp->llc_extent.e_end) {
+			args->lsa_rc = LSE_NOT_ZERO_LENGTH_EXTENDABLE;
+			goto out_err;
+		}
+
+		/* End must come after end of previous comp */
+		if (prev && comp->llc_extent.e_end < prev->llc_extent.e_end) {
+			args->lsa_rc = LSE_END_NOT_GREATER;
+			goto out_err;
+		}
+
+		/* Components not followed by ext space must have length > 0. */
+		if (comp->llc_extent.e_start == comp->llc_extent.e_end &&
+		    (next == NULL || !(next->llc_flags & LCME_FL_EXTENSION))) {
+			args->lsa_rc = LSE_ZERO_LENGTH_NORMAL;
+			goto out_err;
+		}
+
+		/* The component end must be aligned by the stripe size */
+		if ((comp->llc_flags & LCME_FL_EXTENSION) &&
+		    (prev->llc_stripe_size != LLAPI_LAYOUT_DEFAULT)) {
+			if (comp->llc_extent.e_end != LUSTRE_EOF &&
+			    comp->llc_extent.e_end % prev->llc_stripe_size) {
+				args->lsa_rc = LSE_ALIGN_END;
+				goto out_err;
+			}
+			if ((comp->llc_stripe_size * SEL_UNIT_SIZE) %
+			    prev->llc_stripe_size) {
+				args->lsa_rc = LSE_ALIGN_EXT;
+				goto out_err;
+			}
+		} else if (!(comp->llc_flags & LCME_FL_EXTENSION) &&
+			   (comp->llc_stripe_size != LLAPI_LAYOUT_DEFAULT)) {
+			if (comp->llc_extent.e_end != LUSTRE_EOF &&
+			    comp->llc_extent.e_end % comp->llc_stripe_size) {
+				args->lsa_rc = LSE_ALIGN_END;
+				goto out_err;
+			}
+		}
+	}
+
+	/* Components must have start == prev->end */
+	if (prev && comp->llc_extent.e_start != 0 &&
+	    comp->llc_extent.e_start != prev->llc_extent.e_end) {
+		args->lsa_rc = LSE_NOT_ADJACENT_PREV;
+		goto out_err;
+	}
+
+	/* Components must have start <= end */
+	if (comp->llc_extent.e_start > comp->llc_extent.e_end) {
+		args->lsa_rc = LSE_START_GT_END;
+		goto out_err;
+	}
+
+	return LLAPI_LAYOUT_ITER_CONT;
+
+out_err:
+	errno = errno ? errno : EINVAL;
+	return LLAPI_LAYOUT_ITER_STOP;
+}
+
+/* Print explanation of layout error */
+void llapi_layout_sanity_perror(int error)
+{
+	if (error >= LSE_LAST || error < 0) {
+		fprintf(stdout, "Invalid layout, unrecognized error: %d\n",
+			error);
+	} else {
+		fprintf(stdout, "Invalid layout: %s\n",
+			llapi_layout_strerror[error]);
+	}
+}
+
+/* Walk a layout and enforce sanity checks that apply to > 1 component
+ *
+ * The core idea here is that of sanity checking individual tokens vs semantic
+ * checking.
+ * We cannot check everything at the individual component level ('token'),
+ * instead we must check whether or not the full layout has a valid meaning.
+ *
+ * An example of a component level check is "is stripe size valid?".  That is
+ * handled when setting stripe size.
+ *
+ * An example of a layout level check is "are the extents of these components
+ * valid when adjacent to one another", or "can we set these flags on adjacent
+ * components"?
+ *
+ * \param[in] layout            component layout list.
+ * \param[in] incomplete        if layout is complete or not - some checks can
+ *                              only be done on complete layouts.
+ * \param[in] flr		set when this is called from FLR mirror create
+ *
+ * \retval                      0, success, positive: various errors, see
+ *                              llapi_layout_sanity_perror, -1, failure
+ */
+int llapi_layout_sanity(struct llapi_layout *layout, bool incomplete, bool flr)
+{
+	struct llapi_layout_sanity_args args;
+	struct llapi_layout_comp *curr;
+	int rc = 0;
+
+	if (!layout)
+		return 0;
+
+	curr = layout->llot_cur_comp;
+	if (!curr)
+		return 0;
+
+	/* Set up args */
+	args.lsa_rc = 0;
+	args.lsa_flr = flr;
+	args.lsa_incomplete = incomplete;
+
+	/* When we modify an existing layout, this tells us if it's FLR */
+	if (mirror_id_of(curr->llc_id) > 0)
+		args.lsa_flr = true;
+
+	errno = 0;
+	rc = llapi_layout_comp_iterate(layout,
+				       llapi_layout_sanity_cb,
+				       &args);
+	if (errno == ENOENT)
+		errno = 0;
+
+	if (rc != LLAPI_LAYOUT_ITER_CONT)
+		rc = args.lsa_rc;
+
+	layout->llot_cur_comp = curr;
+
+	return rc;
+}
+
+int llapi_layout_dom_size(struct llapi_layout *layout, uint64_t *size)
+{
+	uint64_t pattern, start;
+	int rc;
+
+	if (!layout || !llapi_layout_is_composite(layout)) {
+		*size = 0;
+		return 0;
+	}
+
+	rc = llapi_layout_comp_use(layout, LLAPI_LAYOUT_COMP_USE_FIRST);
+	if (rc)
+		return -errno;
+
+	rc = llapi_layout_pattern_get(layout, &pattern);
+	if (rc)
+		return -errno;
+
+	if (pattern != LOV_PATTERN_MDT && pattern != LLAPI_LAYOUT_MDT) {
+		*size = 0;
+		return 0;
+	}
+
+	rc = llapi_layout_comp_extent_get(layout, &start, size);
+	if (rc)
+		return -errno;
+	if (start)
+		return -ERANGE;
 	return 0;
 }
+
+int lov_comp_md_size(struct lov_comp_md_v1 *lcm)
+{
+	if (lcm->lcm_magic == LOV_MAGIC_V1 || lcm->lcm_magic == LOV_MAGIC_V3) {
+		struct lov_user_md *lum = (void *)lcm;
+
+		return lov_user_md_size(lum->lmm_stripe_count, lum->lmm_magic);
+	}
+
+	if (lcm->lcm_magic == LOV_MAGIC_FOREIGN) {
+		struct lov_foreign_md *lfm = (void *)lcm;
+
+		return lfm->lfm_length;
+	}
+
+	if (lcm->lcm_magic != LOV_MAGIC_COMP_V1)
+		return -EOPNOTSUPP;
+
+	return lcm->lcm_size;
+}
+
+int llapi_get_lum_file_fd(int dir_fd, const char *fname, __u64 *valid,
+			  lstatx_t *statx, struct lov_user_md *lum,
+			  size_t lumsize)
+{
+	struct lov_user_mds_data *lmd;
+	char buf[65536 + offsetof(typeof(*lmd), lmd_lmm)];
+	int parent_fd = -1;
+	int rc;
+
+	if (lum && lumsize < sizeof(*lum))
+		return -EINVAL;
+
+	/* If a file name is provided, it is relative to the parent directory */
+	if (fname) {
+		parent_fd = dir_fd;
+		dir_fd = -1;
+	}
+
+	lmd = (struct lov_user_mds_data *)buf;
+	rc = get_lmd_info_fd(fname, parent_fd, dir_fd, buf, sizeof(buf),
+			     GET_LMD_INFO);
+	if (rc)
+		return rc;
+
+	if (valid)
+		*valid = lmd->lmd_flags;
+
+	if (statx)
+		memcpy(statx, &lmd->lmd_stx, sizeof(*statx));
+
+	if (lum) {
+		if (lmd->lmd_lmmsize > lumsize)
+			return -EOVERFLOW;
+		memcpy(lum, &lmd->lmd_lmm, lmd->lmd_lmmsize);
+	}
+
+	return 0;
+}
+
+int llapi_get_lum_dir_fd(int dir_fd, __u64 *valid, lstatx_t *statx,
+			 struct lov_user_md *lum, size_t lumsize)
+{
+	return llapi_get_lum_file_fd(dir_fd, NULL, valid, statx, lum, lumsize);
+}
+
+int llapi_get_lum_file(const char *path, __u64 *valid, lstatx_t *statx,
+		       struct lov_user_md *lum, size_t lumsize)
+{
+	char parent[PATH_MAX];
+	const char *fname;
+	char *tmp;
+	int offset;
+	int dir_fd;
+	int rc;
+
+	tmp = strrchr(path, '/');
+	if (!tmp) {
+		strncpy(parent, ".", sizeof(parent) - 1);
+		offset = -1;
+	} else {
+		strncpy(parent, path, tmp - path);
+		offset = tmp - path - 1;
+		parent[tmp - path] = 0;
+	}
+
+	fname = path;
+	if (offset >= 0)
+		fname += offset + 2;
+
+	dir_fd = open(parent, O_RDONLY);
+	if (dir_fd < 0) {
+		rc = -errno;
+		llapi_error(LLAPI_MSG_ERROR, rc, "cannot open '%s'", path);
+		return rc;
+	}
+
+	rc = llapi_get_lum_file_fd(dir_fd, fname, valid, statx, lum, lumsize);
+	close(dir_fd);
+	return rc;
+}
+
+int llapi_get_lum_dir(const char *path, __u64 *valid, lstatx_t *statx,
+		      struct lov_user_md *lum, size_t lumsize)
+{
+	int dir_fd;
+	int rc;
+
+	dir_fd = open(path, O_RDONLY);
+	if (dir_fd < 0) {
+		rc = -errno;
+		llapi_error(LLAPI_MSG_ERROR, rc, "cannot open '%s'", path);
+		return rc;
+	}
+
+	rc = llapi_get_lum_dir_fd(dir_fd, valid, statx, lum, lumsize);
+	close(dir_fd);
+	return rc;
+}