client: use common interp of st_nlink for dirs

Apparently some applications use this (like mail servers) and since it's
trivial to support, let's do it. Idea is that st_nlinks for a directory is
either 0 (it is unlinked) or 2 + the number of sub-directories (which have ..
parent links).

Fixes: https://tracker.ceph.com/issues/23873
Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>

diff --git a/src/client/Client.cc b/src/client/Client.cc
index e9658b13e5fdf05864d484d0d7f9983eedbd6b3d..2a54b8603ea20805dd5084e278d3eb943443cea1 100644 (file)
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -7056,7 +7056,22 @@ int Client::fill_stat(Inode *in, struct stat *st, frag_info_t *dirstat, nest_inf
   st->st_dev = in->snapid;
   st->st_mode = in->mode;
   st->st_rdev = in->rdev;
-  st->st_nlink = in->nlink;
+  if (in->is_dir()) {
+    switch (in->nlink) {
+      case 0:
+        st->st_nlink = 0; /* dir is unlinked */
+        break;
+      case 1:
+        st->st_nlink = 1 /* parent dentry */
+                       + 1 /* <dir>/. */
+                       + in->dirstat.nsubdirs; /* include <dir>/. self-reference */
+        break;
+      default:
+        ceph_abort();
+    }
+  } else {
+    st->st_nlink = in->nlink;
+  }
   st->st_uid = in->uid;
   st->st_gid = in->gid;
   if (in->ctime > in->mtime) {
@@ -7123,7 +7138,22 @@ void Client::fill_statx(Inode *in, unsigned int mask, struct ceph_statx *stx)
   }
 
   if (mask & CEPH_CAP_LINK_SHARED) {
-    stx->stx_nlink = in->nlink;
+    if (in->is_dir()) {
+      switch (in->nlink) {
+        case 0:
+          stx->stx_nlink = 0; /* dir is unlinked */
+          break;
+        case 1:
+          stx->stx_nlink = 1 /* parent dentry */
+                           + 1 /* <dir>/. */
+                           + in->dirstat.nsubdirs; /* include <dir>/. self-reference */
+          break;
+        default:
+          ceph_abort();
+      }
+    } else {
+      stx->stx_nlink = in->nlink;
+    }
     stx->stx_mask |= CEPH_STATX_NLINK;
   }
 

diff --git a/src/client/Inode.cc b/src/client/Inode.cc
index 7d9e9ad3ceb452efd0de5ba3dd3505035776a21a..1a03e7d9243b029fe00e1248d1af890b9a092d28 100644 (file)
--- a/src/client/Inode.cc
+++ b/src/client/Inode.cc
@@ -46,6 +46,7 @@ ostream& operator<<(ostream &out, const Inode &in)
       << " open=" << in.open_by_mode
       << " mode=" << oct << in.mode << dec
       << " size=" << in.size << "/" << in.max_size
+      << " nlink=" << in.nlink
       << " btime=" << in.btime
       << " mtime=" << in.mtime
       << " ctime=" << in.ctime

diff --git a/src/test/libcephfs/test.cc b/src/test/libcephfs/test.cc
index 1ccd84a0b877d8b2e555c8ab0f96242018b0f530..1b79812a5ac0cbf043220ae48cf0d206f05f7989 100644 (file)
--- a/src/test/libcephfs/test.cc
+++ b/src/test/libcephfs/test.cc
@@ -614,6 +614,68 @@ TEST(LibCephFS, LstatSlashdot) {
   ceph_shutdown(cmount);
 }
 
+TEST(LibCephFS, StatDirNlink) {
+  struct ceph_mount_info *cmount;
+  ASSERT_EQ(ceph_create(&cmount, NULL), 0);
+  ASSERT_EQ(ceph_conf_read_file(cmount, NULL), 0);
+  ASSERT_EQ(0, ceph_conf_parse_env(cmount, NULL));
+  ASSERT_EQ(ceph_mount(cmount, NULL), 0);
+
+  char test_dir1[256];
+  sprintf(test_dir1, "dir1_symlinks_%d", getpid());
+  ASSERT_EQ(ceph_mkdir(cmount, test_dir1, 0700), 0);
+
+  int fd = ceph_open(cmount, test_dir1, O_DIRECTORY|O_RDONLY, 0);
+  ASSERT_GT(fd, 0);
+  struct ceph_statx stx;
+  ASSERT_EQ(ceph_fstatx(cmount, fd, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+  ASSERT_EQ(stx.stx_nlink, 2);
+
+  {
+    char test_dir2[256];
+    sprintf(test_dir2, "%s/.", test_dir1);
+    ASSERT_EQ(ceph_statx(cmount, test_dir2, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+    ASSERT_EQ(stx.stx_nlink, 2);
+  }
+
+  {
+    char test_dir2[256];
+    sprintf(test_dir2, "%s/1", test_dir1);
+    ASSERT_EQ(ceph_mkdir(cmount, test_dir2, 0700), 0);
+    ASSERT_EQ(ceph_statx(cmount, test_dir2, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+    ASSERT_EQ(stx.stx_nlink, 2);
+      ASSERT_EQ(ceph_statx(cmount, test_dir1, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+      ASSERT_EQ(stx.stx_nlink, 3);
+    sprintf(test_dir2, "%s/2", test_dir1);
+    ASSERT_EQ(ceph_mkdir(cmount, test_dir2, 0700), 0);
+      ASSERT_EQ(ceph_statx(cmount, test_dir1, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+      ASSERT_EQ(stx.stx_nlink, 4);
+    sprintf(test_dir2, "%s/1/1", test_dir1);
+    ASSERT_EQ(ceph_mkdir(cmount, test_dir2, 0700), 0);
+      ASSERT_EQ(ceph_statx(cmount, test_dir1, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+      ASSERT_EQ(stx.stx_nlink, 4);
+    ASSERT_EQ(ceph_rmdir(cmount, test_dir2), 0);
+      ASSERT_EQ(ceph_statx(cmount, test_dir1, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+      ASSERT_EQ(stx.stx_nlink, 4);
+    sprintf(test_dir2, "%s/1", test_dir1);
+    ASSERT_EQ(ceph_rmdir(cmount, test_dir2), 0);
+      ASSERT_EQ(ceph_statx(cmount, test_dir1, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+      ASSERT_EQ(stx.stx_nlink, 3);
+    sprintf(test_dir2, "%s/2", test_dir1);
+    ASSERT_EQ(ceph_rmdir(cmount, test_dir2), 0);
+      ASSERT_EQ(ceph_statx(cmount, test_dir1, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+      ASSERT_EQ(stx.stx_nlink, 2);
+  }
+
+  ASSERT_EQ(ceph_rmdir(cmount, test_dir1), 0);
+  ASSERT_EQ(ceph_fstatx(cmount, fd, &stx, CEPH_STATX_NLINK, AT_SYMLINK_NOFOLLOW), 0);
+  ASSERT_EQ(stx.stx_nlink, 0);
+
+  ceph_close(cmount, fd);
+
+  ceph_shutdown(cmount);
+}
+
 TEST(LibCephFS, DoubleChmod) {
 
   struct ceph_mount_info *cmount;