fix: avoid inode unlink due to net error

When creating a file, the client will create inode first and then send a
create dentry request. If create dentry request fails due to a net
error (e.g. send the request to metanode but timed out when getting
response), there is a tiny chance that the dentry is created
successfully on metanode. Thus we cannot unlink the inode created
previously because we would rather leave the orphan inode than create
an orphan dentry.

Signed-off-by: Shuoran Liu <[email protected]>

sdk/meta/api.go

@@ -95,14 +95,14 @@ func (mw *MetaWrapper) Create_ll(parentID uint64, name string, mode, uid, gid ui
 
 create_dentry:
 	status, err = mw.dcreate(parentMP, parentID, name, info.Inode, mode)
-	if err != nil || status != statusOK {
-		if status == statusExist {
-			return nil, syscall.EEXIST
-		} else {
+	if err != nil {
+		return nil, statusToErrno(status)
+	} else if status != statusOK {
+		if status != statusExist {
 			mw.iunlink(mp, info.Inode)
 			mw.ievict(mp, info.Inode)
-			return nil, statusToErrno(status)
 		}
+		return nil, statusToErrno(status)
 	}
 	return info, nil
 }
@@ -297,15 +297,13 @@ func (mw *MetaWrapper) Rename_ll(srcParentID uint64, srcName string, dstParentID
 	// create dentry in dst parent
 	status, err = mw.dcreate(dstParentMP, dstParentID, dstName, inode, mode)
 	if err != nil {
-		mw.iunlink(srcMP, inode)
 		return syscall.EAGAIN
 	}
 
 	// Note that only regular files are allowed to be overwritten.
 	if status == statusExist && proto.IsRegular(mode) {
 		status, oldInode, err = mw.dupdate(dstParentMP, dstParentID, dstName, inode)
 		if err != nil {
-			mw.iunlink(srcMP, inode)
 			return syscall.EAGAIN
 		}
 	}
@@ -317,7 +315,9 @@ func (mw *MetaWrapper) Rename_ll(srcParentID uint64, srcName string, dstParentID
 
 	// delete dentry from src parent
 	status, _, err = mw.ddelete(srcParentMP, srcParentID, srcName)
-	if err != nil || status != statusOK {
+	if err != nil {
+		return statusToErrno(status)
+	} else if status != statusOK {
 		var (
 			sts int
 			e   error
@@ -469,13 +469,13 @@ func (mw *MetaWrapper) Link(parentID uint64, name string, ino uint64) (*proto.In
 
 	// create new dentry and refer to the inode
 	status, err = mw.dcreate(parentMP, parentID, name, ino, info.Mode)
-	if err != nil || status != statusOK {
-		if status == statusExist {
-			return nil, syscall.EEXIST
-		} else {
+	if err != nil {
+		return nil, statusToErrno(status)
+	} else if status != statusOK {
+		if status != statusExist {
 			mw.iunlink(mp, ino)
-			return nil, syscall.EAGAIN
 		}
+		return nil, statusToErrno(status)
 	}
 	return info, nil
 }