--- a/security/manager/ssl/nsNSSComponent.cpp
+++ b/security/manager/ssl/nsNSSComponent.cpp
@@ -53,16 +53,21 @@
 #include "pkix/pkixnss.h"
 #include "secerr.h"
 #include "secmod.h"
 #include "ssl.h"
 #include "sslerr.h"
 #include "sslproto.h"
 #include "prmem.h"
 
+#if defined(XP_LINUX) && !defined(ANDROID)
+#include <linux/magic.h>
+#include <sys/vfs.h>
+#endif
+
 #ifdef XP_WIN
 #include "mozilla/WindowsVersion.h"
 #include "nsILocalFileWin.h"
 
 #include "windows.h" // this needs to be before the following includes
 #include "lmcons.h"
 #include "sddl.h"
 #include "wincrypt.h"
@@ -1748,51 +1753,65 @@ nsNSSComponent::setEnabledTLSVersions()
     SSL_VersionRangeSetDefault(ssl_variant_stream, &filledInRange);
   if (srv != SECSuccess) {
     return NS_ERROR_FAILURE;
   }
 
   return NS_OK;
 }
 
-#ifdef XP_WIN
+#if defined(XP_WIN) || (defined(XP_LINUX) && !defined(ANDROID))
 // If the profile directory is on a networked drive, we want to set the
 // environment variable NSS_SDB_USE_CACHE to yes (as long as it hasn't been set
 // before).
 static void
 SetNSSDatabaseCacheModeAsAppropriate()
 {
   nsCOMPtr<nsIFile> profileFile;
   nsresult rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
                                        getter_AddRefs(profileFile));
   if (NS_FAILED(rv)) {
     // We're probably running without a profile directory, so this is
     // irrelevant.
     return;
   }
 
-  nsCOMPtr<nsILocalFileWin> profileFileWin(do_QueryInterface(profileFile));
-  if (!profileFileWin) {
-    MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("couldn't get nsILocalFileWin?"));
-    return;
+  static const char sNSS_SDB_USE_CACHE[] = "NSS_SDB_USE_CACHE";
+  static const char sNSS_SDB_USE_CACHE_WITH_VALUE[] = "NSS_SDB_USE_CACHE=yes";
+  auto profilePath = profileFile->NativePath();
+
+#if defined(XP_LINUX) && !defined(ANDROID)
+  struct statfs statfs_s;
+  if (statfs(profilePath.get(), &statfs_s) == 0 &&
+      statfs_s.f_type == NFS_SUPER_MAGIC &&
+      !PR_GetEnv(sNSS_SDB_USE_CACHE)) {
+    MOZ_LOG(gPIPNSSLog, LogLevel::Debug,
+            ("profile is remote (and NSS_SDB_USE_CACHE wasn't set): "
+             "setting NSS_SDB_USE_CACHE"));
+    PR_SetEnv(sNSS_SDB_USE_CACHE_WITH_VALUE);
+  } else {
+    MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("not setting NSS_SDB_USE_CACHE"));
   }
-  auto profilePath = profileFile->NativePath();
+#endif // defined(XP_LINUX) && !defined(ANDROID)
+
+#ifdef XP_WIN
   wchar_t volPath[MAX_PATH];
   if (::GetVolumePathNameW(profilePath.get(), volPath, MAX_PATH) &&
       ::GetDriveTypeW(volPath) == DRIVE_REMOTE &&
-      !PR_GetEnv("NSS_SDB_USE_CACHE")) {
+      !PR_GetEnv(sNSS_SDB_USE_CACHE)) {
     MOZ_LOG(gPIPNSSLog, LogLevel::Debug,
             ("profile is remote (and NSS_SDB_USE_CACHE wasn't set): "
              "setting NSS_SDB_USE_CACHE"));
-    PR_SetEnv("NSS_SDB_USE_CACHE=yes");
+    PR_SetEnv(sNSS_SDB_USE_CACHE_WITH_VALUE);
   } else {
     MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("not setting NSS_SDB_USE_CACHE"));
   }
+#endif // XP_WIN
 }
-#endif // XP_WIN
+#endif // defined(XP_WIN) || (defined(XP_LINUX) && !defined(ANDROID))
 
 static nsresult
 GetNSSProfilePath(nsAutoCString& aProfilePath)
 {
   aProfilePath.Truncate();
   nsCOMPtr<nsIFile> profileFile;
   nsresult rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
                                        getter_AddRefs(profileFile));
@@ -2044,17 +2063,17 @@ nsNSSComponent::InitializeNSS()
   ConfigureInternalPKCS11Token();
 
   nsAutoCString profileStr;
   nsresult rv = GetNSSProfilePath(profileStr);
   if (NS_FAILED(rv)) {
     return NS_ERROR_NOT_AVAILABLE;
   }
 
-#ifdef XP_WIN
+#if defined(XP_WIN) || (defined(XP_LINUX) && !defined(ANDROID))
   SetNSSDatabaseCacheModeAsAppropriate();
 #endif
 
   bool nocertdb = Preferences::GetBool("security.nocertdb", false);
   bool inSafeMode = true;
   nsCOMPtr<nsIXULRuntime> runtime(do_GetService("@mozilla.org/xre/runtime;1"));
   // There might not be an nsIXULRuntime in embedded situations. This will
   // default to assuming we are in safe mode (as a result, no external PKCS11