rbd: refactor do_import_diff to accept fd.

Signed-off-by: Dongsheng Yang <dongsheng.yang@easystack.cn>

diff --git a/src/tools/rbd/action/Import.cc b/src/tools/rbd/action/Import.cc
index d1e1ac0528a439ba22e7e053bec1521df8ac3059..9d039f1cec1bd2d03f5f1a2e08281caa532b20fc 100644 (file)
--- a/src/tools/rbd/action/Import.cc
+++ b/src/tools/rbd/action/Import.cc
@@ -20,10 +20,10 @@
 namespace rbd {
 namespace action {
 
-int do_import_diff(librbd::Image &image, const char *path,
-                bool no_progress)
+int do_import_diff_fd(librbd::Image &image, int fd,
+                  bool no_progress)
 {
-  int fd, r;
+  int r;
   struct stat stat_buf;
   utils::ProgressContext pc("Importing image diff", no_progress);
   uint64_t size = 0;
@@ -31,16 +31,8 @@ int do_import_diff(librbd::Image &image, const char *path,
   string from, to;
   char buf[utils::RBD_DIFF_BANNER.size() + 1];
 
-  bool from_stdin = !strcmp(path, "-");
-  if (from_stdin) {
-    fd = 0;
-  } else {
-    fd = open(path, O_RDONLY);
-    if (fd < 0) {
-      r = -errno;
-      std::cerr << "rbd: error opening " << path << std::endl;
-      return r;
-    }
+  bool from_stdin = (fd == 0);
+  if (!from_stdin) {
     r = ::fstat(fd, &stat_buf);
     if (r < 0)
       goto done;
@@ -53,7 +45,7 @@ int do_import_diff(librbd::Image &image, const char *path,
   buf[utils::RBD_DIFF_BANNER.size()] = '\0';
   if (strcmp(buf, utils::RBD_DIFF_BANNER.c_str())) {
     std::cerr << "invalid banner '" << buf << "', expected '"
-              << utils::RBD_DIFF_BANNER << "'" << std::endl;
+            << utils::RBD_DIFF_BANNER << "'" << std::endl;
     r = -EINVAL;
     goto done;
   }
@@ -70,43 +62,43 @@ int do_import_diff(librbd::Image &image, const char *path,
     } else if (tag == RBD_DIFF_FROM_SNAP) {
       r = utils::read_string(fd, 4096, &from);   // 4k limit to make sure we don't get a garbage string
       if (r < 0)
-        goto done;
+       goto done;
 
       bool exists; 
       r = image.snap_exists2(from.c_str(), &exists);
       if (r < 0)
-        goto done;
+       goto done;
 
       if (!exists) {
-        std::cerr << "start snapshot '" << from
-                  << "' does not exist in the image, aborting" << std::endl;
-        r = -EINVAL;
-        goto done;
+       std::cerr << "start snapshot '" << from
+                 << "' does not exist in the image, aborting" << std::endl;
+       r = -EINVAL;
+       goto done;
       }
     }
     else if (tag == RBD_DIFF_TO_SNAP) {
       r = utils::read_string(fd, 4096, &to);   // 4k limit to make sure we don't get a garbage string
       if (r < 0)
-        goto done;
+       goto done;
 
       // verify this snap isn't already present
       bool exists;
       r = image.snap_exists2(to.c_str(), &exists);
       if (r < 0)
-        goto done;
+       goto done;
       
       if (exists) {
-        std::cerr << "end snapshot '" << to
-                  << "' already exists, aborting" << std::endl;
-        r = -EEXIST;
-        goto done;
+       std::cerr << "end snapshot '" << to
+                 << "' already exists, aborting" << std::endl;
+       r = -EEXIST;
+       goto done;
       }
     } else if (tag == RBD_DIFF_IMAGE_SIZE) {
       uint64_t end_size;
       char buf[8];
       r = safe_read_exact(fd, buf, 8);
       if (r < 0)
-        goto done;
+       goto done;
       bufferlist bl;
       bl.append(buf, 8);
       bufferlist::iterator p = bl.begin();
@@ -114,17 +106,16 @@ int do_import_diff(librbd::Image &image, const char *path,
       uint64_t cur_size;
       image.size(&cur_size);
       if (cur_size != end_size) {
-        image.resize(end_size);
-      } else {
+       image.resize(end_size);
       }
       if (from_stdin)
-        size = end_size;
+       size = end_size;
     } else if (tag == RBD_DIFF_WRITE || tag == RBD_DIFF_ZERO) {
       uint64_t len;
       char buf[16];
       r = safe_read_exact(fd, buf, 16);
       if (r < 0)
-        goto done;
+       goto done;
       bufferlist bl;
       bl.append(buf, 16);
       bufferlist::iterator p = bl.begin();
@@ -132,19 +123,19 @@ int do_import_diff(librbd::Image &image, const char *path,
       ::decode(len, p);
 
       if (tag == RBD_DIFF_WRITE) {
-        bufferptr bp = buffer::create(len);
-        r = safe_read_exact(fd, bp.c_str(), len);
-        if (r < 0)
-          goto done;
-        bufferlist data;
-        data.append(bp);
-        image.write2(off, len, data, LIBRADOS_OP_FLAG_FADVISE_NOCACHE);
+       bufferptr bp = buffer::create(len);
+       r = safe_read_exact(fd, bp.c_str(), len);
+       if (r < 0)
+         goto done;
+       bufferlist data;
+       data.append(bp);
+       image.write2(off, len, data, LIBRADOS_OP_FLAG_FADVISE_NOCACHE);
       } else {
-        image.discard(off, len);
+       image.discard(off, len);
       }
     } else {
       std::cerr << "unrecognized tag byte " << (int)tag
-                << " in stream; aborting" << std::endl;
+               << " in stream; aborting" << std::endl;
       r = -EINVAL;
       goto done;
     }
@@ -163,12 +154,33 @@ int do_import_diff(librbd::Image &image, const char *path,
     r = image.snap_create(to.c_str());
   }
 
- done:
+done:
   if (r < 0)
     pc.fail();
   else
     pc.finish();
-  if (!from_stdin)
+  return r;
+}
+
+int do_import_diff(librbd::Image &image, const char *path,
+                bool no_progress)
+{
+  int r;
+  int fd;
+
+  if (strcmp(path, "-") == 0) {
+    fd = 0;
+  } else {
+    fd = open(path, O_RDONLY);
+    if (fd < 0) {
+      r = -errno;
+      std::cerr << "rbd: error opening " << path << std::endl;
+      return r;
+    }
+  }
+  r = do_import_diff_fd(image, fd, no_progress);
+
+  if (fd != 0)
     close(fd);
   return r;
 }