diff --git a/src/XrdCeph/XrdCephPosix.cc b/src/XrdCeph/XrdCephPosix.cc
index 644490ca00a..d0fadbeff60 100644
--- a/src/XrdCeph/XrdCephPosix.cc
+++ b/src/XrdCeph/XrdCephPosix.cc
@@ -42,6 +42,7 @@
 #include <time.h>
 #include <limits>
 #include "XrdSfs/XrdSfsAio.hh"
+#include "XrdSys/XrdSysPthread.hh"
 
 #include "XrdCeph/XrdCephPosix.hh"
 
@@ -69,22 +70,79 @@ struct DirIterator {
 
 /// small struct for aio API callbacks
 struct AioArgs {
-  AioArgs(XrdSfsAio* a, AioCB *b, size_t n) : aiop(a), callback(b), nbBytes(n) {}
+  AioArgs(XrdSfsAio* a, AioCB *b, size_t n, ceph::bufferlist *_bl=0) :
+    aiop(a), callback(b), nbBytes(n), bl(_bl) {}
   XrdSfsAio* aiop;
   AioCB *callback;
   size_t nbBytes;
+  ceph::bufferlist *bl;
 };
 
 /// global variables holding stripers and ioCtxs for each ceph pool plus the cluster object
 std::map<std::string, libradosstriper::RadosStriper*> g_radosStripers;
 std::map<std::string, librados::IoCtx*> g_ioCtx;
 librados::Rados* g_cluster = 0;
-/// global variable holding a map of file descriptor to file reference
-std::map<unsigned int, CephFileRef> g_fds;
+/// mutex protecting the striper and ioctx maps
+XrdSysMutex g_striper_mutex;
+
 /// global variable holding a list of files currently opened for write
 std::multiset<std::string> g_filesOpenForWrite;
+/// global variable holding a map of file descriptor to file reference
+std::map<unsigned int, CephFileRef> g_fds;
 /// global variable remembering the next available file descriptor
 unsigned int g_nextCephFd = 0;
+/// mutex protecting the map of file descriptors and the openForWrite multiset
+XrdSysMutex g_fd_mutex;
+
+/// check whether a file is open for write
+bool isOpenForWrite(std::string& name) {
+  XrdSysMutexHelper lock(g_fd_mutex);
+  return g_filesOpenForWrite.find(name) != g_filesOpenForWrite.end();
+}
+
+/// insert a filename in the list of files opened for write
+void insertOpenForWrite(std::string& name) {
+  XrdSysMutexHelper lock(g_fd_mutex);
+  g_filesOpenForWrite.insert(name);
+}
+
+/// delete a filename from the list of files opened for write
+void deleteOpenForWrite(std::string& name) {
+  XrdSysMutexHelper lock(g_fd_mutex);
+  g_filesOpenForWrite.erase(g_filesOpenForWrite.find(name));
+}
+
+/// look for a FileRef from its file descriptor
+CephFileRef* getFileRef(int fd) {
+  XrdSysMutexHelper lock(g_fd_mutex);
+  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
+  if (it != g_fds.end()) {
+    return &(it->second);
+  } else {
+    return 0;
+  }
+}
+
+/// deletes a FileRef from the global table of file descriptors
+void deleteFileRef(int fd) {
+  XrdSysMutexHelper lock(g_fd_mutex);
+  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
+  if (it != g_fds.end()) {
+    g_fds.erase(it);
+  }
+}
+
+/**
+ * inserts a new FileRef into the global table of file descriptors
+ * and return the associated file descriptor
+ */
+int insertFileRef(CephFileRef &fr) {
+  XrdSysMutexHelper lock(g_fd_mutex);
+  g_fds[g_nextCephFd] = fr;
+  g_nextCephFd++;
+  return g_nextCephFd-1;
+}
+
 /// global variable containing defaults for CephFiles
 CephFile g_defaultParams = { "",
                              "default",        // default pool
@@ -311,7 +369,7 @@ static CephFileRef getCephFileRef(const char *path, XrdOucEnv *env, int flags,
   return fr;
 }
 
-static libradosstriper::RadosStriper* getRadosStriper(const CephFile& file) {
+static libradosstriper::RadosStriper* getRadosStriperNoLock(const CephFile& file) {
   std::stringstream ss;
   ss << file.userId << '@' << file.pool << ',' << file.nbStripes << ','
      << file.stripeUnit << ',' << file.objectSize;
@@ -420,8 +478,14 @@ static libradosstriper::RadosStriper* getRadosStriper(const CephFile& file) {
   return it->second;
 }
 
+static libradosstriper::RadosStriper* getRadosStriper(const CephFile& file) {
+  XrdSysMutexHelper lock(g_striper_mutex);
+  return getRadosStriperNoLock(file);
+}
+
 static librados::IoCtx* getIoCtx(const CephFile& file) {
-  libradosstriper::RadosStriper *striper = getRadosStriper(file);
+  XrdSysMutexHelper lock(g_striper_mutex);
+  libradosstriper::RadosStriper *striper = getRadosStriperNoLock(file);
   if (0 == striper) {
     return 0;
   }
@@ -433,6 +497,7 @@ static librados::IoCtx* getIoCtx(const CephFile& file) {
 }
 
 void ceph_posix_disconnect_all() {
+  XrdSysMutexHelper lock(g_striper_mutex);
   for (std::map<std::string, libradosstriper::RadosStriper*>::iterator it =
          g_radosStripers.begin();
        it != g_radosStripers.end();
@@ -456,12 +521,11 @@ void ceph_posix_set_logfunc(void (*logfunc) (char *, va_list argp)) {
 static int ceph_posix_internal_truncate(const CephFile &file, unsigned long long size);
 
 int ceph_posix_open(XrdOucEnv* env, const char *pathname, int flags, mode_t mode) {
-  logwrapper((char*)"ceph_open : fd %d associated to %s", g_nextCephFd, pathname);
   CephFileRef fr = getCephFileRef(pathname, env, flags, mode, 0);
-  g_fds[g_nextCephFd] = fr;
-  g_nextCephFd++;
+  int fd = insertFileRef(fr);
+  logwrapper((char*)"ceph_open : fd %d associated to %s", fd, pathname);
   if (flags & (O_WRONLY|O_RDWR)) {
-    g_filesOpenForWrite.insert(fr.name);
+    insertOpenForWrite(fr.name);
   }
   // in case of O_CREAT and O_EXCL, we should complain if the file exists
   if ((flags & O_CREAT) && (flags & O_EXCL)) {
@@ -480,17 +544,17 @@ int ceph_posix_open(XrdOucEnv* env, const char *pathname, int flags, mode_t mode
     // fail only if file exists and cannot be truncated
     if (rc < 0 && rc != -ENOENT) return rc;
   }
-  return g_nextCephFd-1;
+  return fd;
 }
 
 int ceph_posix_close(int fd) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_close: closed fd %d", fd);
-    if (it->second.flags & (O_WRONLY|O_RDWR)) {
-      g_filesOpenForWrite.erase(g_filesOpenForWrite.find(it->second.name));
+    if (fr->flags & (O_WRONLY|O_RDWR)) {
+      deleteOpenForWrite(fr->name);
     }
-    g_fds.erase(it);
+    deleteFileRef(fd);
     return 0;
   } else {
     return -EBADF;
@@ -512,44 +576,41 @@ static off64_t lseek_compute_offset(CephFileRef &fr, off64_t offset, int whence)
 }
 
 off_t ceph_posix_lseek(int fd, off_t offset, int whence) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_lseek: for fd %d, offset=%lld, whence=%d", fd, offset, whence);
-    return (off_t)lseek_compute_offset(fr, offset, whence);
+    return (off_t)lseek_compute_offset(*fr, offset, whence);
   } else {
     return -EBADF;
   }
 }
 
 off64_t ceph_posix_lseek64(int fd, off64_t offset, int whence) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_lseek64: for fd %d, offset=%lld, whence=%d", fd, offset, whence);
-    return lseek_compute_offset(fr, offset, whence);
+    return lseek_compute_offset(*fr, offset, whence);
   } else {
     return -EBADF;
   }
 }
 
 ssize_t ceph_posix_write(int fd, const void *buf, size_t count) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_write: for fd %d, count=%d", fd, count);
-    if ((fr.flags & (O_WRONLY|O_RDWR)) == 0) {
+    if ((fr->flags & (O_WRONLY|O_RDWR)) == 0) {
       return -EBADF;
     }
-    libradosstriper::RadosStriper *striper = getRadosStriper(fr);
+    libradosstriper::RadosStriper *striper = getRadosStriper(*fr);
     if (0 == striper) {
       return -EINVAL;
     }
     ceph::bufferlist bl;
     bl.append((const char*)buf, count);
-    int rc = striper->write(fr.name, bl, count, fr.offset);
+    int rc = striper->write(fr->name, bl, count, fr->offset);
     if (rc) return rc;
-    fr.offset += count;
+    fr->offset += count;
     return count;
   } else {
     return -EBADF;
@@ -557,20 +618,19 @@ ssize_t ceph_posix_write(int fd, const void *buf, size_t count) {
 }
 
 ssize_t ceph_posix_pwrite(int fd, const void *buf, size_t count, off64_t offset) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_write: for fd %d, count=%d", fd, count);
-    if ((fr.flags & (O_WRONLY|O_RDWR)) == 0) {
+    if ((fr->flags & (O_WRONLY|O_RDWR)) == 0) {
       return -EBADF;
     }
-    libradosstriper::RadosStriper *striper = getRadosStriper(fr);
+    libradosstriper::RadosStriper *striper = getRadosStriper(*fr);
     if (0 == striper) {
       return -EINVAL;
     }
     ceph::bufferlist bl;
     bl.append((const char*)buf, count);
-    int rc = striper->write(fr.name, bl, count, offset);
+    int rc = striper->write(fr->name, bl, count, offset);
     if (rc) return rc;
     return count;
   } else {
@@ -578,7 +638,7 @@ ssize_t ceph_posix_pwrite(int fd, const void *buf, size_t count, off64_t offset)
   }
 }
 
-static void ceph_aio_complete(rados_completion_t c, void *arg) {
+static void ceph_aio_write_complete(rados_completion_t c, void *arg) {
   AioArgs *awa = reinterpret_cast<AioArgs*>(arg);
   size_t rc = rados_aio_get_return_value(c);
   awa->callback(awa->aiop, rc == 0 ? awa->nbBytes : rc);
@@ -586,19 +646,18 @@ static void ceph_aio_complete(rados_completion_t c, void *arg) {
 }
 
 ssize_t ceph_aio_write(int fd, XrdSfsAio *aiop, AioCB *cb) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     // get the parameters from the Xroot aio object
     size_t count = aiop->sfsAio.aio_nbytes;
     const char *buf = (const char*)aiop->sfsAio.aio_buf;
     size_t offset = aiop->sfsAio.aio_offset;
     // get the striper object
-    CephFileRef &fr = it->second;
     logwrapper((char*)"ceph_aio_write: for fd %d, count=%d", fd, count);
-    if ((fr.flags & (O_WRONLY|O_RDWR)) == 0) {
+    if ((fr->flags & (O_WRONLY|O_RDWR)) == 0) {
       return -EBADF;
     }
-    libradosstriper::RadosStriper *striper = getRadosStriper(fr);
+    libradosstriper::RadosStriper *striper = getRadosStriper(*fr);
     if (0 == striper) {
       return -EINVAL;
     }
@@ -608,32 +667,31 @@ ssize_t ceph_aio_write(int fd, XrdSfsAio *aiop, AioCB *cb) {
     // prepare a ceph AioCompletion object and do async call
     AioArgs *args = new AioArgs(aiop, cb, count);
     librados::AioCompletion *completion =
-      g_cluster->aio_create_completion(args, ceph_aio_complete, NULL);
-    int rc = striper->aio_write(fr.name, completion, bl, count, offset);
+      g_cluster->aio_create_completion(args, ceph_aio_write_complete, NULL);
+    int rc = striper->aio_write(fr->name, completion, bl, count, offset);
     completion->release();
     return rc;
   } else {
     return -EBADF;
   }
-} 
+}
 
 ssize_t ceph_posix_read(int fd, void *buf, size_t count) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_read: for fd %d, count=%d", fd, count);
-    if ((fr.flags & (O_WRONLY|O_RDWR)) != 0) {
+    if ((fr->flags & (O_WRONLY|O_RDWR)) != 0) {
       return -EBADF;
     }
-    libradosstriper::RadosStriper *striper = getRadosStriper(fr);
+    libradosstriper::RadosStriper *striper = getRadosStriper(*fr);
     if (0 == striper) {
       return -EINVAL;
     }
     ceph::bufferlist bl;
-    int rc = striper->read(fr.name, &bl, count, fr.offset);
+    int rc = striper->read(fr->name, &bl, count, fr->offset);
     if (rc < 0) return rc;
     bl.copy(0, rc, (char*)buf);
-    fr.offset += rc;
+    fr->offset += rc;
     return rc;
   } else {
     return -EBADF;
@@ -641,19 +699,18 @@ ssize_t ceph_posix_read(int fd, void *buf, size_t count) {
 }
 
 ssize_t ceph_posix_pread(int fd, void *buf, size_t count, off64_t offset) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_read: for fd %d, count=%d", fd, count);
-    if ((fr.flags & (O_WRONLY|O_RDWR)) != 0) {
+    if ((fr->flags & (O_WRONLY|O_RDWR)) != 0) {
       return -EBADF;
     }
-    libradosstriper::RadosStriper *striper = getRadosStriper(fr);
+    libradosstriper::RadosStriper *striper = getRadosStriper(*fr);
     if (0 == striper) {
       return -EINVAL;
     }
     ceph::bufferlist bl;
-    int rc = striper->read(fr.name, &bl, count, offset);
+    int rc = striper->read(fr->name, &bl, count, offset);
     if (rc < 0) return rc;
     bl.copy(0, rc, (char*)buf);
     return rc;
@@ -662,33 +719,43 @@ ssize_t ceph_posix_pread(int fd, void *buf, size_t count, off64_t offset) {
   }
 }
 
+static void ceph_aio_read_complete(rados_completion_t c, void *arg) {
+  AioArgs *awa = reinterpret_cast<AioArgs*>(arg);
+  size_t rc = rados_aio_get_return_value(c);
+  if (awa->bl) {
+    if (rc > 0) {
+      awa->bl->copy(0, rc, (char*)awa->aiop->sfsAio.aio_buf);
+    }
+    delete awa->bl;
+    awa->bl = 0;
+  }
+  awa->callback(awa->aiop, rc == 0 ? awa->nbBytes : rc);
+  delete(awa);
+}
+
 ssize_t ceph_aio_read(int fd, XrdSfsAio *aiop, AioCB *cb) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     // get the parameters from the Xroot aio object
     size_t count = aiop->sfsAio.aio_nbytes;
-    const char *buf = (const char*)aiop->sfsAio.aio_buf;
     size_t offset = aiop->sfsAio.aio_offset;
     // get the striper object
-    CephFileRef &fr = it->second;
     logwrapper((char*)"ceph_read: for fd %d, count=%d", fd, count);
-    if ((fr.flags & (O_WRONLY|O_RDWR)) != 0) {
+    if ((fr->flags & (O_WRONLY|O_RDWR)) != 0) {
       return -EBADF;
     }
-    libradosstriper::RadosStriper *striper = getRadosStriper(fr);
+    libradosstriper::RadosStriper *striper = getRadosStriper(*fr);
     if (0 == striper) {
       return -EINVAL;
     }
     // prepare a bufferlist to receive data
-    ceph::bufferlist bl;
+    ceph::bufferlist *bl = new ceph::bufferlist();
     // prepare a ceph AioCompletion object and do async call
-    AioArgs *args = new AioArgs(aiop, cb, count);
+    AioArgs *args = new AioArgs(aiop, cb, count, bl);
     librados::AioCompletion *completion =
-      g_cluster->aio_create_completion(args, ceph_aio_complete, NULL);
-    int rc = striper->aio_read(fr.name, completion, &bl, count, offset);
+      g_cluster->aio_create_completion(args, ceph_aio_read_complete, NULL);
+    int rc = striper->aio_read(fr->name, completion, bl, count, offset);
     completion->release();
-    if (rc < 0) return rc;
-    bl.copy(0, rc, (char*)buf);
     return rc;
   } else {
     return -EBADF;
@@ -696,19 +763,18 @@ ssize_t ceph_aio_read(int fd, XrdSfsAio *aiop, AioCB *cb) {
 }
 
 int ceph_posix_fstat(int fd, struct stat *buf) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_stat: fd %d", fd);
     // minimal stat : only size and times are filled
     // atime, mtime and ctime are set all to the same value
     // mode is set arbitrarily to 0666
-    libradosstriper::RadosStriper *striper = getRadosStriper(fr);
+    libradosstriper::RadosStriper *striper = getRadosStriper(*fr);
     if (0 == striper) {
       return -EINVAL;
     }
     memset(buf, 0, sizeof(*buf));
-    int rc = striper->stat(fr.name, (uint64_t*)&(buf->st_size), &(buf->st_atime));
+    int rc = striper->stat(fr->name, (uint64_t*)&(buf->st_size), &(buf->st_atime));
     if (rc != 0) {
       return -rc;
     }
@@ -736,7 +802,7 @@ int ceph_posix_stat(XrdOucEnv* env, const char *pathname, struct stat *buf) {
   if (rc != 0) {
     // for non existing file. Check that we did not open it for write recently
     // in that case, we return 0 size and current time
-    if (-ENOENT == rc && g_filesOpenForWrite.find(file.name) != g_filesOpenForWrite.end()) {
+    if (-ENOENT == rc && isOpenForWrite(file.name)) {
       buf->st_size = 0;
       buf->st_atime = time(NULL);
     } else {
@@ -750,8 +816,8 @@ int ceph_posix_stat(XrdOucEnv* env, const char *pathname, struct stat *buf) {
 }
 
 int ceph_posix_fsync(int fd) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_sync: fd %d", fd);
     return 0;
   } else {
@@ -760,14 +826,13 @@ int ceph_posix_fsync(int fd) {
 }
 
 int ceph_posix_fcntl(int fd, int cmd, ... /* arg */ ) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_fcntl: fd %d cmd=%d", fd, cmd);
     // minimal implementation
     switch (cmd) {
     case F_GETFL:
-      return fr.mode;
+      return fr->mode;
     default:
       return -EINVAL;
     }
@@ -799,11 +864,10 @@ ssize_t ceph_posix_getxattr(XrdOucEnv* env, const char* path,
 
 ssize_t ceph_posix_fgetxattr(int fd, const char* name,
                              void* value, size_t size) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_fgetxattr: fd %d name=%s", fd, name);
-    return ceph_posix_internal_getxattr(fr, name, value, size);
+    return ceph_posix_internal_getxattr(*fr, name, value, size);
   } else {
     return -EBADF;
   }
@@ -834,11 +898,10 @@ ssize_t ceph_posix_setxattr(XrdOucEnv* env, const char* path,
 int ceph_posix_fsetxattr(int fd,
                          const char* name, const void* value,
                          size_t size, int flags)  {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_fsetxattr: fd %d name=%s value=%s", fd, name, value);
-    return ceph_posix_internal_setxattr(fr, name, value, size, flags);
+    return ceph_posix_internal_setxattr(*fr, name, value, size, flags);
   } else {
     return -EBADF;
   }
@@ -863,11 +926,10 @@ int ceph_posix_removexattr(XrdOucEnv* env, const char* path,
 }
 
 int ceph_posix_fremovexattr(int fd, const char* name) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_fremovexattr: fd %d name=%s", fd, name);
-    return ceph_posix_internal_removexattr(fr, name);
+    return ceph_posix_internal_removexattr(*fr, name);
   } else {
     return -EBADF;
   }
@@ -913,11 +975,10 @@ int ceph_posix_listxattrs(XrdOucEnv* env, const char* path, XrdSysXAttr::AList *
 }
 
 int ceph_posix_flistxattrs(int fd, XrdSysXAttr::AList **aPL, int getSz) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_flistxattrs: fd %d", fd);
-    return ceph_posix_internal_listxattrs(fr, aPL, getSz);
+    return ceph_posix_internal_listxattrs(*fr, aPL, getSz);
   } else {
     return -EBADF;
   }
@@ -952,11 +1013,10 @@ static int ceph_posix_internal_truncate(const CephFile &file, unsigned long long
 }
 
 int ceph_posix_ftruncate(int fd, unsigned long long size) {
-  std::map<unsigned int, CephFileRef>::iterator it = g_fds.find(fd);
-  if (it != g_fds.end()) {
-    CephFileRef &fr = it->second;
+  CephFileRef* fr = getFileRef(fd);
+  if (fr) {
     logwrapper((char*)"ceph_posix_ftruncate: fd %d, size %d", fd, size);
-    return ceph_posix_internal_truncate(fr, size);
+    return ceph_posix_internal_truncate(*fr, size);
   } else {
     return -EBADF;
   }