Warn users if a file with multiple hard links is encountered during backup.

2 files changed, 31 insertions, 2 deletions

diff --git a/bin/bbackupd/BackupClientDirectoryRecord.cpp b/bin/bbackupd/BackupClientDirectoryRecord.cpp
index 6f14fa0c..ed72fe18 100644
--- a/bin/bbackupd/BackupClientDirectoryRecord.cpp
+++ b/bin/bbackupd/BackupClientDirectoryRecord.cpp
@@ -53,6 +53,7 @@ BackupClientDirectoryRecord::BackupClientDirectoryRecord(int64_t ObjectID, const
 	  mSubDirName(rSubDirName),
 	  mInitialSyncDone(false),
 	  mSyncDone(false),
+	  mSuppressMultipleLinksWarning(false),
 	  mpPendingEntries(0)
 {
 	::memset(mStateChecksum, 0, sizeof(mStateChecksum));
@@ -321,13 +322,40 @@ void BackupClientDirectoryRecord::SyncDirectory(
 					continue;
 				}
 
+				int type = file_st.st_mode & S_IFMT;
+
+				// ecryptfs reports nlink > 1 for directories
+				// with contents, but no filesystem supports
+				// hardlinking directories? so we can ignore
+				// this if the entry is a directory.
+				if(file_st.st_nlink != 1 && type == S_IFDIR)
+				{
+					BOX_INFO("Ignoring apparent hard link "
+						"count on directory: " <<
+						filename << ", nlink=" <<
+						file_st.st_nlink);
+				}
+				else if(file_st.st_nlink != 1)
+				{
+					if(!mSuppressMultipleLinksWarning)
+					{
+						BOX_WARNING("File is hard linked, this may "
+							"cause rename tracking to fail and "
+							"move files incorrectly in your "
+							"backup! " << filename << 
+							", nlink=" << file_st.st_nlink <<
+							" (suppressing further warnings");
+						mSuppressMultipleLinksWarning = true;
+					}
+					SetErrorWhenReadingFilesystemObject(
+						rParams, filename.c_str());
+				}
+
 				BOX_TRACE("Stat entry '" << filename << "' "
 					"found device/inode " <<
 					file_st.st_dev << "/" <<
 					file_st.st_ino);
 
-				int type = file_st.st_mode & S_IFMT;
-
 				/* Workaround for apparent btrfs bug, where
 				symlinks appear to be on a different filesystem
 				than their containing directory, thanks to
diff --git a/bin/bbackupd/BackupClientDirectoryRecord.h b/bin/bbackupd/BackupClientDirectoryRecord.h
index 1a03ff41..d9291520 100644
--- a/bin/bbackupd/BackupClientDirectoryRecord.h
+++ b/bin/bbackupd/BackupClientDirectoryRecord.h
@@ -156,6 +156,7 @@ private:
 	std::string 	mSubDirName;
 	bool 		mInitialSyncDone;
 	bool 		mSyncDone;
+	bool		mSuppressMultipleLinksWarning;
 
 	// Checksum of directory contents and attributes, used to detect changes
 	uint8_t mStateChecksum[MD5Digest::DigestLength];