chimera: fix loop creation on directory move

Motivation:
On directory move we must check that destination is not a subdirectory
on the source directory.

Modification:
Update JdbcFs#rename to check for a potential loop creation before move.
Added unit test to cover the use case.

Result:
no more loops on directory move.

Fixes: #7559
Ticket: #10608
Acked-by: Dmitry Litvintsev
Acked-by: Paul Millar
Target: master, 10.0, 9.2, 9.1, 9.0, 8.2
Require-book: no
Require-notes: yes
(cherry picked from commit 72da8e9)
Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>

modules/chimera/src/main/java/org/dcache/chimera/FsSqlDriver.java

@@ -18,6 +18,7 @@
 
 import static java.util.stream.Collectors.toList;
 import static org.dcache.chimera.FileSystemProvider.SetXattrMode;
+import static org.dcache.chimera.FileSystemProvider.StatCacheOption.NO_STAT;
 import static org.dcache.chimera.FileSystemProvider.StatCacheOption.STAT;
 
 import com.google.common.base.Strings;
@@ -50,6 +51,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.OptionalLong;
 import java.util.ServiceLoader;
 import java.util.Set;
 import java.util.stream.Collectors;
@@ -474,7 +476,13 @@ FsInode mkdir(FsInode parent, String name, int owner, int group, int mode) {
      * @param inode
      * @return true if moved, false if source did not exist
      */
-    boolean rename(FsInode inode, FsInode srcDir, String source, FsInode destDir, String dest) {
+    boolean rename(FsInode inode, FsInode srcDir, String source, FsInode destDir, String dest) throws ChimeraFsException {
+
+        // If source is a directory check that we don't move into its own subdirectory
+        if (inode.isDirectory()) {
+            checkLoop(inode, destDir);
+        }
+
         String moveLink = "UPDATE t_dirs SET iparent=?, iname=? WHERE iparent=? AND iname=? AND ichild=?";
         int n = _jdbc.update(moveLink,
               ps -> {
@@ -577,6 +585,30 @@ protected String inode2path(long elementId, long root) {
         }
     }
 
+    protected void checkLoop(FsInode inode, FsInode dst) throws InvalidArgumentChimeraException {
+        if (inode.ino() == dst.ino()) {
+            throw new InvalidArgumentChimeraException("Cannot move directory into itself.");
+        }
+
+        long destInumber = dst.ino();
+        while (true) {
+            OptionalLong parent = _jdbc.query("SELECT iparent FROM t_dirs WHERE ichild=?",
+                    rs -> rs.next() ? OptionalLong.of(rs.getLong("iparent")) : OptionalLong.empty(),
+                    destInumber);
+
+            if (parent.isEmpty()) {
+                // we have reached the root of the three
+                break;
+            }
+
+            long parentIno = parent.getAsLong();
+            if (parentIno == inode.ino()) {
+                throw new InvalidArgumentChimeraException("Cannot move directory into its own subdirectory.");
+            }
+            destInumber = parentIno;
+        }
+    }
+
     FsInode createInodeInParent(FsInode parent, String name, String id, int owner, int group,
           int mode,
           int type, int nlink, long size) {

modules/chimera/src/test/java/org/dcache/chimera/JdbcFsTest.java

@@ -990,7 +990,8 @@ public void testMoveIntoDir() throws Exception {
 
     @Test(expected = FileNotFoundChimeraFsException.class)
     public void testMoveNotExists() throws Exception {
-        _fs.rename(_rootInode, _rootInode, "foo", _rootInode, "bar");
+        FsInode dummy = new FsInode(_fs, 31415);
+        _fs.rename(dummy, _rootInode, "foo", _rootInode, "bar");
     }
 
     @Test(expected = DirNotEmptyChimeraFsException.class)
@@ -2046,6 +2047,23 @@ public void testRemoveXattrAfterSet() throws Exception {
               _fs.stat(inode).getGeneration(), greaterThan(s0.getGeneration()));
     }
 
+    @Test(expected = InvalidArgumentChimeraException.class)
+    public void testMvDirectoryIntoItself() throws Exception {
+
+        FsInode dir = _fs.mkdir("/dir");
+        _fs.rename(dir, _rootInode, "dir", dir, "subdir");
+    }
+
+    @Test(expected = InvalidArgumentChimeraException.class)
+    public void testMvDirectoryOwnSubtree() throws Exception {
+
+        FsInode dir = _fs.mkdir("/dir");
+        _fs.mkdir("/dir/subdir1");
+        FsInode dir2 = _fs.mkdir("/dir/subdir1/subdir2");
+
+        _fs.rename(dir, _rootInode, "dir", dir2, "subdir3");
+    }
+
     private long getDirEntryCount(FsInode dir) throws IOException {
         try (var s = _fs.newDirectoryStream(dir)) {
             return s.stream().count();