libcephfs: fix crash on getpwd

...if the directory has been unlinked in
the background.  Previously this would
assert out, now it will just give you
the last string that you passed into chdir.

Signed-off-by: John Spray <john.spray@redhat.com>

diff --git a/src/client/Client.cc b/src/client/Client.cc
index 53984d29059d9f934daaa45684d0bb75dbffb74a..206e1dd1eb36f910ee8505b1d21a38bdad079861 100644 (file)
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -8663,7 +8663,7 @@ int Client::fstat(int fd, struct stat *stbuf)
 
 // not written yet, but i want to link!
 
-int Client::chdir(const char *relpath)
+int Client::chdir(const char *relpath, std::string &new_cwd)
 {
   Mutex::Locker lock(client_lock);
   tout(cct) << "chdir" << std::endl;
@@ -8676,6 +8676,8 @@ int Client::chdir(const char *relpath)
   if (cwd != in)
     cwd.swap(in);
   ldout(cct, 3) << "chdir(" << relpath << ")  cwd now " << cwd->ino << dendl;
+
+  getcwd(new_cwd);
   return 0;
 }
 
@@ -8687,7 +8689,15 @@ void Client::getcwd(string& dir)
   Inode *in = cwd.get();
   while (in != root) {
     assert(in->dn_set.size() < 2); // dirs can't be hard-linked
+
+    // A cwd or ancester is unlinked
+    if (in->dn_set.empty()) {
+      return;
+    }
+
     Dentry *dn = in->get_first_parent();
+
+
     if (!dn) {
       // look it up
       ldout(cct, 10) << "getcwd looking up parent for " << *in << dendl;

diff --git a/src/client/Client.h b/src/client/Client.h
index 67b5c5e9c813ba3fd7af073d4ea872536ad3fe41..d53ca1df169a44b1609167991e76d1773f61cd53 100644 (file)
--- a/src/client/Client.h
+++ b/src/client/Client.h
@@ -892,7 +892,7 @@ public:
   int statfs(const char *path, struct statvfs *stbuf);
 
   // crap
-  int chdir(const char *s);
+  int chdir(const char *s, std::string &new_cwd);
   void getcwd(std::string& cwd);
 
   // namespace ops

diff --git a/src/client/SyntheticClient.cc b/src/client/SyntheticClient.cc
index 78fd7ce51200e6e3c4855280e244a2d2567f69af..b2ef93ae30ba5c151eb12c4cf7d970987d3383fe 100644 (file)
--- a/src/client/SyntheticClient.cc
+++ b/src/client/SyntheticClient.cc
@@ -1206,7 +1206,10 @@ int SyntheticClient::play_trace(Trace& t, string& prefix, bool metadata_only)
       client->fsync(fd, b);
     } else if (strcmp(op, "chdir") == 0) {
       const char *a = t.get_string(buf, p);
-      client->chdir(a);
+      // Client users should remember their path, but since this
+      // is just a synthetic client we ignore it.
+      std::string ignore;
+      client->chdir(a, ignore);
     } else if (strcmp(op, "statfs") == 0) {
       struct statvfs stbuf;
       client->statfs("/", &stbuf);

diff --git a/src/libcephfs.cc b/src/libcephfs.cc
index 037a018a595686783eb617147a13cabf1a32aa62..b01cf227abb2e4b7f717f647f4ad083352768b76 100644 (file)
--- a/src/libcephfs.cc
+++ b/src/libcephfs.cc
@@ -231,6 +231,11 @@ public:
     return cwd.c_str();
   }
 
+  int chdir(const char *to)
+  {
+    return client->chdir(to, cwd);
+  }
+
   CephContext *get_ceph_context() const {
     return cct;
   }
@@ -454,7 +459,7 @@ extern "C" int ceph_chdir (struct ceph_mount_info *cmount, const char *s)
 {
   if (!cmount->is_mounted())
     return -ENOTCONN;
-  return cmount->get_client()->chdir(s);
+  return cmount->chdir(s);
 }
 
 extern "C" int ceph_opendir(struct ceph_mount_info *cmount,

diff --git a/src/test/pybind/test_cephfs.py b/src/test/pybind/test_cephfs.py
index d2f3eb640596c415ec864ca44fdc2b12f16208c0..77cd31bf994675aa4ed956d57079dd428f631ee6 100644 (file)
--- a/src/test/pybind/test_cephfs.py
+++ b/src/test/pybind/test_cephfs.py
@@ -143,3 +143,15 @@ def test_symlink():
     cephfs.close(fd)
     cephfs.unlink('file-2')
 
+@with_setup(setup_test)
+def test_delete_cwd():
+    assert_equal("/", cephfs.getcwd())
+
+    cephfs.mkdir("/temp-directory", 0755)
+    cephfs.chdir("/temp-directory")
+    cephfs.rmdir("/temp-directory")
+
+    # getcwd gives you something stale here: it remembers the path string
+    # even when things are unlinked.  It's up to the caller to find out
+    # whether it really still exists
+    assert_equal("/temp-directory", cephfs.getcwd())