rbd:export/import image-meta when we export/import an image

when we do exporting/importing an image, we should export or import the image-meta of this image at the same time

Signed-off-by: PCzhangPC <pengcheng.zhang@easystack.cn>

doc/dev/rbd-export.rst

@@ -65,6 +65,20 @@ Image Stripe count
 - le64: length of appending data (8)
 - le64: image striping count
 
+ImageMeta Key
+-------------
+
+- u8: 'K'
+- le64: length of appending data
+- string: image-meta key
+
+ImageMeta Value
+---------------
+
+- u8: 'V'
+- le64: length of appending data
+- string: image-meta value
+
 Final Record
 ~~~~~~~~~~~~
 

qa/workunits/rbd/import_export.sh

@@ -79,10 +79,16 @@ if rbd help export | grep -q export-format; then
     dd if=/bin/dd of=${TMPDIR}/img bs=1k count=10 seek=100
     rbd import $RBD_CREATE_ARGS ${TMPDIR}/img testimg
     rbd snap create testimg@snap
+    rbd image-meta set testimg key1 value1
+    IMAGEMETA_BEFORE=`rbd image-meta list testimg`
     rbd export --export-format 2 testimg ${TMPDIR}/img_v2
     rbd import --export-format 2 ${TMPDIR}/img_v2 testimg_import
     rbd info testimg_import
     rbd info testimg_import@snap
+    IMAGEMETA_AFTER=`rbd image-meta list testimg_import`
+    if [ "$IMAGEMETA_BEFORE" != "$IMAGEMETA_AFTER" ]; then
+        false
+    fi
 
     # compare the contents between testimg and testimg_import
     rbd export testimg_import ${TMPDIR}/img_import

src/tools/rbd/Utils.h

@@ -50,6 +50,8 @@ static const std::string RBD_DIFF_BANNER_V2 ("rbd diff v2\n");
 #define RBD_EXPORT_IMAGE_FEATURES	'T'
 #define RBD_EXPORT_IMAGE_STRIPE_UNIT	'U'
 #define RBD_EXPORT_IMAGE_STRIPE_COUNT	'C'
+#define RBD_EXPORT_IMAGEMETA_KEY		'K'
+#define RBD_EXPORT_IMAGEMETA_VALUE		'V'
 #define RBD_EXPORT_IMAGE_END		'E'
 
 enum SnapshotPresence {

src/tools/rbd/action/Export.cc

@@ -414,6 +414,38 @@ static int do_export_v2(librbd::Image& image, librbd::image_info_t &info, int fd
   ::encode(length, bl);
   ::encode(stripe_count, bl);
 
+  //encode imageMeta key and value
+  std::map<std::string, bufferlist> pairs;
+
+  r = image.metadata_list("", 0, &pairs);
+  if (r < 0) {
+    std::cerr << "failed to retrieve metadata of image : " << cpp_strerror(r)
+              << std::endl;
+    return r;
+  }
+
+  if (!pairs.empty()) {
+    for (std::map<std::string, bufferlist>::iterator it = pairs.begin();
+         it != pairs.end(); ++it) {
+      string key(it->first.c_str(), it->first.length());
+      string value(it->second.c_str(), it->second.length());
+
+      //encode imageMeta key
+      tag = RBD_EXPORT_IMAGEMETA_KEY;
+      length = key.length();
+      ::encode(tag, bl);
+      ::encode(length, bl);
+      bl.append(key.data());
+
+      //encode imageMeta value
+      tag = RBD_EXPORT_IMAGEMETA_VALUE;
+      length = value.length();
+      ::encode(tag, bl);
+      ::encode(length, bl);
+      bl.append(value.data());
+    }
+  }
+
   // encode end tag
   tag = RBD_EXPORT_IMAGE_END;
   ::encode(tag, bl);

src/tools/rbd/action/Import.cc

@@ -555,7 +555,45 @@ static int decode_and_set_image_option(int fd, uint64_t imageopt, librbd::ImageO
   return 0;
 }
 
-static int do_import_header(int fd, int import_format, uint64_t &size, librbd::ImageOptions& opts)
+static int read_imagemeta_key_or_value(int fd, string &val, uint64_t length)
+{
+  int r;
+
+  char buf[length];
+  r = safe_read_exact(fd, buf, length);
+  if (r < 0) {
+    return r;
+  }
+
+  val.assign(buf, length);
+
+  return 0;
+}
+
+static int do_import_imagemeta(int import_format, librbd::Image& image,
+                               std::map<std::string, std::string> &pairs)
+{
+  int r = 0;
+
+  //v1 format
+  if (import_format == 1) {
+    return r;
+  }
+
+  if (!pairs.empty()) {
+    for (std::map<std::string, std::string>::iterator it = pairs.begin();
+         it != pairs.end(); ++it) {
+      r = image.metadata_set(it->first, it->second);
+      if (r < 0)
+        return r;
+    }
+  }
+
+  return r;
+}
+
+static int do_import_header(int fd, int import_format, uint64_t &size, librbd::ImageOptions& opts,
+                            std::map<std::string, std::string> &pairs)
 {
   // There is no header in v1 image.
   if (import_format == 1) {
@@ -578,6 +616,9 @@ static int do_import_header(int fd, int import_format, uint64_t &size, librbd::I
     opts.set(RBD_IMAGE_OPTION_FORMAT, image_format);
   }
 
+  string key;
+  string value;
+
   while (r == 0) {
     __u8 tag;
     uint64_t length;
@@ -594,6 +635,11 @@ static int do_import_header(int fd, int import_format, uint64_t &size, librbd::I
       r = decode_and_set_image_option(fd, RBD_IMAGE_OPTION_STRIPE_UNIT, opts);
     } else if (tag == RBD_EXPORT_IMAGE_STRIPE_COUNT) {
       r = decode_and_set_image_option(fd, RBD_IMAGE_OPTION_STRIPE_COUNT, opts);
+    } else if (tag == RBD_EXPORT_IMAGEMETA_KEY) {
+      r = read_imagemeta_key_or_value(fd, key, length);
+    } else if (tag == RBD_EXPORT_IMAGEMETA_VALUE) {
+      r = read_imagemeta_key_or_value(fd, value, length);
+      pairs[key] = value;
     } else {
       std::cerr << "rbd: invalid tag in image properties zone: " << tag << "Skip it."
                 << std::endl;
@@ -743,6 +789,7 @@ static int do_import(librados::Rados &rados, librbd::RBD &rbd,
   int fd, r;
   struct stat stat_buf;
   utils::ProgressContext pc("Importing image", no_progress);
+  std::map<std::string, std::string> pairs;
 
   assert(imgname);
 
@@ -796,7 +843,7 @@ static int do_import(librados::Rados &rados, librbd::RBD &rbd,
 #endif
   }
 
-  r = do_import_header(fd, import_format, size, opts);
+  r = do_import_header(fd, import_format, size, opts, pairs);
   if (r < 0) {
     std::cerr << "rbd: import header failed." << std::endl;
     goto done;
@@ -814,6 +861,12 @@ static int do_import(librados::Rados &rados, librbd::RBD &rbd,
     goto err;
   }
 
+  r = do_import_imagemeta(import_format, image, pairs);
+  if (r < 0) {
+    std::cerr << "rbd: failed to import image-meta" << std::endl;
+    goto err;
+  }
+
   if (import_format == 1) {
     r = do_import_v1(fd, image, size, imgblklen, pc, sparse_size);
   } else {