client: trim path before logging it

Path can be virtually infinitely long and logging a long long path
(imagine around 2000 path components) is un-useful as well as lowers
readability of the log. Therefore, trim before logging.

Fixes: https://tracker.ceph.com/issues/72993
Signed-off-by: Rishabh Dave <[email protected]>

Author: rishabh-d-dave

src/client/Client.cc

@@ -7689,7 +7689,10 @@ int Client::path_walk(InodeRef dirinode, const filepath& origpath, InodeRef *end
   return rc;
 }
 
-int Client::path_walk(InodeRef dirinode, const filepath& origpath, walk_dentry_result* result, const UserPerm& perms, const PathWalk_ExtraOptions& extra_options)
+int Client::path_walk(InodeRef dirinode, const filepath& origpath,
+		      walk_dentry_result* result, const UserPerm& perms,
+		      const PathWalk_ExtraOptions& extra_options,
+		      std::string trimmed_path)
 {
   int rc = 0;
   filepath path = origpath;
@@ -7713,7 +7716,11 @@ int Client::path_walk(InodeRef dirinode, const filepath& origpath, walk_dentry_r
   int symlinks = 0;
   unsigned i = 0;
 
-  ldout(cct, 10) << __func__ << ": cur=" << *diri << " path=" << path << dendl;
+  if (trimmed_path == "") {
+    std::string trimmed_path = path.get_trimmed_path();
+  }
+
+  ldout(cct, 10) << __func__ << ": cur=" << *diri << " path=" << trimmed_path << dendl;
 
   if (path.depth() == 0) {
     /* diri/dname can also be used as a filepath; or target */
@@ -7727,7 +7734,7 @@ int Client::path_walk(InodeRef dirinode, const filepath& origpath, walk_dentry_r
     int caps = 0;
     dname = path[i];
     ldout(cct, 10) << " " << i << " " << *diri << " " << dname << dendl;
-    ldout(cct, 20) << "  (path is " << path << ")" << dendl;
+    ldout(cct, 20) << "  (path is " << trimmed_path << ")" << dendl;
     InodeRef next;
     if (!diri.get()->is_dir()) {
       ldout(cct, 20) << diri.get() << " is not a dir inode, name " << dname.c_str() << dendl;
@@ -15420,11 +15427,12 @@ int Client::ll_unlink(Inode *in, const char *name, const UserPerm& perm)
 
 int Client::_rmdir(Inode *dir, const char *name, const UserPerm& perms, bool check_perms)
 {
-  ldout(cct, 8) << "_rmdir(" << dir->ino << " " << name << " uid "
+  std::string trimmed_path = filepath(name).get_trimmed_path();
+  ldout(cct, 8) << "_rmdir(" << dir->ino << " " << trimmed_path << " uid "
 		<< perms.uid() << " gid " << perms.gid() << ")" << dendl;
 
   walk_dentry_result wdr;
-  if (int rc = path_walk(dir, filepath(name), &wdr, perms, {.followsym = false}); rc < 0) {
+  if (int rc = path_walk(dir, filepath(name), &wdr, perms, {.followsym = false}, trimmed_path); rc < 0) {
     return rc;
   }
 

src/client/Client.h

@@ -1073,7 +1073,7 @@ class Client : public Dispatcher, public md_config_obs_t {
     bool is_rename = false;
     bool require_target = true;
   };
-  int path_walk(InodeRef dirinode, const filepath& fp, struct walk_dentry_result* result, const UserPerm& perms, const PathWalk_ExtraOptions& extra_options);
+  int path_walk(InodeRef dirinode, const filepath& fp, struct walk_dentry_result* result, const UserPerm& perms, const PathWalk_ExtraOptions& extra_options, std::string trimmed_path=std::string());
   int path_walk(InodeRef dirinode, const filepath& fp, InodeRef *end, const UserPerm& perms, const PathWalk_ExtraOptions& extra_options);
 
   // fake inode number for 32-bits ino_t

src/include/filepath.cc

@@ -17,6 +17,21 @@
 
 #include <ostream>
 
+/* Trim given path to final 10 components and return it by prefixing it with
+ * "..."  to indicate that the path has been trimmed. */
+std::string filepath::get_trimmed_path() const
+{
+  std::size_t n = 0;
+  for (int i = 1; i <= 10; ++i) {
+    n = path.rfind("/", n - 1);
+    if (n == std::string::npos) {
+      return std::string(path);
+    }
+  }
+
+  return std::string("..." + path.substr(n, -1));
+}
+
 void filepath::rebuild_path() {
   path.clear();
   for (unsigned i=0; i<bits.size(); i++) {

src/include/filepath.h

@@ -86,6 +86,7 @@ class filepath {
   inodeno_t get_ino() const { return ino; }
   const std::string& get_path() const { return path; }
   void set_trimmed();
+  std::string get_trimmed_path() const;
   const char *c_str() const { return path.c_str(); }
 
   int length() const { return path.length(); }