diff --git a/src/journal/test-journal-flush.c b/src/journal/test-journal-flush.c
index f0a7024002..dc05126b57 100644
--- a/src/journal/test-journal-flush.c
+++ b/src/journal/test-journal-flush.c
@@ -14,6 +14,7 @@
 #include "string-util.h"
 
 int main(int argc, char *argv[]) {
+        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
         _cleanup_free_ char *fn = NULL;
         char dn[] = "/var/tmp/test-journal-flush.XXXXXX";
         JournaldFile *new_journal = NULL;
@@ -21,12 +22,14 @@ int main(int argc, char *argv[]) {
         unsigned n = 0;
         int r;
 
+        m = mmap_cache_new();
+        assert_se(m != NULL);
         assert_se(mkdtemp(dn));
         (void) chattr_path(dn, FS_NOCOW_FL, FS_NOCOW_FL, NULL);
 
         fn = path_join(dn, "test.journal");
 
-        r = journald_file_open(-1, fn, O_CREAT|O_RDWR, 0644, false, 0, false, NULL, NULL, NULL, NULL, &new_journal);
+        r = journald_file_open(-1, fn, O_CREAT|O_RDWR, 0644, false, 0, false, NULL, m, NULL, NULL, &new_journal);
         assert_se(r >= 0);
 
         if (argc > 1)
diff --git a/src/journal/test-journal-interleaving.c b/src/journal/test-journal-interleaving.c
index 48be6a14bc..c543b87b69 100644
--- a/src/journal/test-journal-interleaving.c
+++ b/src/journal/test-journal-interleaving.c
@@ -34,8 +34,13 @@ _noreturn_ static void log_assert_errno(const char *text, int error, const char
         } while (false)
 
 static JournaldFile *test_open(const char *name) {
+        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
         JournaldFile *f;
-        assert_ret(journald_file_open(-1, name, O_RDWR|O_CREAT, 0644, true, UINT64_MAX, false, NULL, NULL, NULL, NULL, &f));
+
+        m = mmap_cache_new();
+        assert_se(m != NULL);
+
+        assert_ret(journald_file_open(-1, name, O_RDWR|O_CREAT, 0644, true, UINT64_MAX, false, NULL, m, NULL, NULL, &f));
         return f;
 }
 
@@ -198,15 +203,19 @@ static void test_skip(void (*setup)(void)) {
 
 static void test_sequence_numbers(void) {
 
+        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
         char t[] = "/var/tmp/journal-seq-XXXXXX";
         JournaldFile *one, *two;
         uint64_t seqnum = 0;
         sd_id128_t seqnum_id;
 
+        m = mmap_cache_new();
+        assert_se(m != NULL);
+
         mkdtemp_chdir_chattr(t);
 
         assert_se(journald_file_open(-1, "one.journal", O_RDWR|O_CREAT, 0644,
-                                     true, UINT64_MAX, false, NULL, NULL, NULL, NULL, &one) == 0);
+                                     true, UINT64_MAX, false, NULL, m, NULL, NULL, &one) == 0);
 
         append_number(one, 1, &seqnum);
         printf("seqnum=%"PRIu64"\n", seqnum);
@@ -223,7 +232,7 @@ static void test_sequence_numbers(void) {
         memcpy(&seqnum_id, &one->file->header->seqnum_id, sizeof(sd_id128_t));
 
         assert_se(journald_file_open(-1, "two.journal", O_RDWR|O_CREAT, 0644,
-                                     true, UINT64_MAX, false, NULL, NULL, NULL, one, &two) == 0);
+                                     true, UINT64_MAX, false, NULL, m, NULL, one, &two) == 0);
 
         assert_se(two->file->header->state == STATE_ONLINE);
         assert_se(!sd_id128_equal(two->file->header->file_id, one->file->header->file_id));
@@ -254,7 +263,7 @@ static void test_sequence_numbers(void) {
         seqnum = 0;
 
         assert_se(journald_file_open(-1, "two.journal", O_RDWR, 0,
-                                     true, UINT64_MAX, false, NULL, NULL, NULL, NULL, &two) == 0);
+                                     true, UINT64_MAX, false, NULL, m, NULL, NULL, &two) == 0);
 
         assert_se(sd_id128_equal(two->file->header->seqnum_id, seqnum_id));
 
diff --git a/src/journal/test-journal-stream.c b/src/journal/test-journal-stream.c
index f7fc4332a9..115ce807c9 100644
--- a/src/journal/test-journal-stream.c
+++ b/src/journal/test-journal-stream.c
@@ -60,6 +60,7 @@ static void verify_contents(sd_journal *j, unsigned skip) {
 }
 
 static void run_test(void) {
+        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
         JournaldFile *one, *two, *three;
         char t[] = "/var/tmp/journal-stream-XXXXXX";
         unsigned i;
@@ -69,13 +70,16 @@ static void run_test(void) {
         size_t l;
         dual_timestamp previous_ts = DUAL_TIMESTAMP_NULL;
 
+        m = mmap_cache_new();
+        assert_se(m != NULL);
+
         assert_se(mkdtemp(t));
         assert_se(chdir(t) >= 0);
         (void) chattr_path(t, FS_NOCOW_FL, FS_NOCOW_FL, NULL);
 
-        assert_se(journald_file_open(-1, "one.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, false, NULL, NULL, NULL, NULL, &one) == 0);
-        assert_se(journald_file_open(-1, "two.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, false, NULL, NULL, NULL, NULL, &two) == 0);
-        assert_se(journald_file_open(-1, "three.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, false, NULL, NULL, NULL, NULL, &three) == 0);
+        assert_se(journald_file_open(-1, "one.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, false, NULL, m, NULL, NULL, &one) == 0);
+        assert_se(journald_file_open(-1, "two.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, false, NULL, m, NULL, NULL, &two) == 0);
+        assert_se(journald_file_open(-1, "three.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, false, NULL, m, NULL, NULL, &three) == 0);
 
         for (i = 0; i < N_ENTRIES; i++) {
                 char *p, *q;
diff --git a/src/journal/test-journal-verify.c b/src/journal/test-journal-verify.c
index cf9692b3d2..6abfaeb0df 100644
--- a/src/journal/test-journal-verify.c
+++ b/src/journal/test-journal-verify.c
@@ -10,6 +10,7 @@
 #include "journald-file.h"
 #include "journal-verify.h"
 #include "log.h"
+#include "mmap-cache.h"
 #include "rm-rf.h"
 #include "terminal-util.h"
 #include "tests.h"
@@ -38,10 +39,14 @@ static void bit_toggle(const char *fn, uint64_t p) {
 }
 
 static int raw_verify(const char *fn, const char *verification_key) {
+        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
         JournalFile *f;
         int r;
 
-        r = journal_file_open(-1, fn, O_RDONLY, 0666, true, UINT64_MAX, !!verification_key, NULL, NULL, NULL, &f);
+        m = mmap_cache_new();
+        assert_se(m != NULL);
+
+        r = journal_file_open(-1, fn, O_RDONLY, 0666, true, UINT64_MAX, !!verification_key, NULL, m, NULL, &f);
         if (r < 0)
                 return r;
 
@@ -52,6 +57,7 @@ static int raw_verify(const char *fn, const char *verification_key) {
 }
 
 int main(int argc, char *argv[]) {
+        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
         char t[] = "/var/tmp/journal-XXXXXX";
         unsigned n;
         JournalFile *f;
@@ -61,6 +67,9 @@ int main(int argc, char *argv[]) {
         struct stat st;
         uint64_t p;
 
+        m = mmap_cache_new();
+        assert_se(m != NULL);
+
         /* journald_file_open requires a valid machine id */
         if (access("/etc/machine-id", F_OK) != 0)
                 return log_tests_skipped("/etc/machine-id not found");
@@ -73,7 +82,7 @@ int main(int argc, char *argv[]) {
 
         log_info("Generating...");
 
-        assert_se(journald_file_open(-1, "test.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, !!verification_key, NULL, NULL, NULL, NULL, &df) == 0);
+        assert_se(journald_file_open(-1, "test.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, !!verification_key, NULL, m, NULL, NULL, &df) == 0);
 
         for (n = 0; n < N_ENTRIES; n++) {
                 struct iovec iovec;
@@ -95,7 +104,7 @@ int main(int argc, char *argv[]) {
 
         log_info("Verifying...");
 
-        assert_se(journal_file_open(-1, "test.journal", O_RDONLY, 0666, true, UINT64_MAX, !!verification_key, NULL, NULL, NULL, &f) == 0);
+        assert_se(journal_file_open(-1, "test.journal", O_RDONLY, 0666, true, UINT64_MAX, !!verification_key, NULL, m, NULL, &f) == 0);
         /* journal_file_print_header(f); */
         journal_file_dump(f);
 
diff --git a/src/journal/test-journal.c b/src/journal/test-journal.c
index 17c6a73db3..11647504e9 100644
--- a/src/journal/test-journal.c
+++ b/src/journal/test-journal.c
@@ -24,6 +24,7 @@ static void mkdtemp_chdir_chattr(char *path) {
 }
 
 static void test_non_empty(void) {
+        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
         dual_timestamp ts;
         JournaldFile *f;
         struct iovec iovec;
@@ -35,9 +36,12 @@ static void test_non_empty(void) {
 
         test_setup_logging(LOG_DEBUG);
 
+        m = mmap_cache_new();
+        assert_se(m != NULL);
+
         mkdtemp_chdir_chattr(t);
 
-        assert_se(journald_file_open(-1, "test.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, true, NULL, NULL, NULL, NULL, &f) == 0);
+        assert_se(journald_file_open(-1, "test.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, true, NULL, m, NULL, NULL, &f) == 0);
 
         assert_se(dual_timestamp_get(&ts));
         assert_se(sd_id128_randomize(&fake_boot_id) == 0);
@@ -98,8 +102,8 @@ static void test_non_empty(void) {
 
         assert_se(journal_file_move_to_entry_by_seqnum(f->file, 10, DIRECTION_DOWN, &o, NULL) == 0);
 
-        journald_file_rotate(&f, NULL, true, UINT64_MAX, true, NULL);
-        journald_file_rotate(&f, NULL, true, UINT64_MAX, true, NULL);
+        journald_file_rotate(&f, m, true, UINT64_MAX, true, NULL);
+        journald_file_rotate(&f, m, true, UINT64_MAX, true, NULL);
 
         (void) journald_file_close(f);
 
@@ -117,17 +121,21 @@ static void test_non_empty(void) {
 }
 
 static void test_empty(void) {
+        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
         JournaldFile *f1, *f2, *f3, *f4;
         char t[] = "/var/tmp/journal-XXXXXX";
 
         test_setup_logging(LOG_DEBUG);
 
+        m = mmap_cache_new();
+        assert_se(m != NULL);
+
         mkdtemp_chdir_chattr(t);
 
-        assert_se(journald_file_open(-1, "test.journal", O_RDWR|O_CREAT, 0666, false, UINT64_MAX, false, NULL, NULL, NULL, NULL, &f1) == 0);
-        assert_se(journald_file_open(-1, "test-compress.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, false, NULL, NULL, NULL, NULL, &f2) == 0);
-        assert_se(journald_file_open(-1, "test-seal.journal", O_RDWR|O_CREAT, 0666, false, UINT64_MAX, true, NULL, NULL, NULL, NULL, &f3) == 0);
-        assert_se(journald_file_open(-1, "test-seal-compress.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, true, NULL, NULL, NULL, NULL, &f4) == 0);
+        assert_se(journald_file_open(-1, "test.journal", O_RDWR|O_CREAT, 0666, false, UINT64_MAX, false, NULL, m, NULL, NULL, &f1) == 0);
+        assert_se(journald_file_open(-1, "test-compress.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, false, NULL, m, NULL, NULL, &f2) == 0);
+        assert_se(journald_file_open(-1, "test-seal.journal", O_RDWR|O_CREAT, 0666, false, UINT64_MAX, true, NULL, m, NULL, NULL, &f3) == 0);
+        assert_se(journald_file_open(-1, "test-seal-compress.journal", O_RDWR|O_CREAT, 0666, true, UINT64_MAX, true, NULL, m, NULL, NULL, &f4) == 0);
 
         journal_file_print_header(f1->file);
         puts("");
@@ -156,6 +164,7 @@ static void test_empty(void) {
 
 #if HAVE_COMPRESSION
 static bool check_compressed(uint64_t compress_threshold, uint64_t data_size) {
+        _cleanup_(mmap_cache_unrefp) MMapCache *m = NULL;
         dual_timestamp ts;
         JournaldFile *f;
         struct iovec iovec;
@@ -170,9 +179,12 @@ static bool check_compressed(uint64_t compress_threshold, uint64_t data_size) {
 
         test_setup_logging(LOG_DEBUG);
 
+        m = mmap_cache_new();
+        assert_se(m != NULL);
+
         mkdtemp_chdir_chattr(t);
 
-        assert_se(journald_file_open(-1, "test.journal", O_RDWR|O_CREAT, 0666, true, compress_threshold, true, NULL, NULL, NULL, NULL, &f) == 0);
+        assert_se(journald_file_open(-1, "test.journal", O_RDWR|O_CREAT, 0666, true, compress_threshold, true, NULL, m, NULL, NULL, &f) == 0);
 
         dual_timestamp_get(&ts);
 
diff --git a/src/libsystemd/sd-journal/journal-file.c b/src/libsystemd/sd-journal/journal-file.c
index 4302a99f80..505e4f728d 100644
--- a/src/libsystemd/sd-journal/journal-file.c
+++ b/src/libsystemd/sd-journal/journal-file.c
@@ -3250,13 +3250,13 @@ int journal_file_open(
                 JournalFile **ret) {
 
         bool newly_created = false;
-        MMapCache *m = mmap_cache;
         JournalFile *f;
         void *h;
         int r;
 
         assert(ret);
         assert(fd >= 0 || fname);
+        assert(mmap_cache);
 
         if (!IN_SET((flags & O_ACCMODE), O_RDONLY, O_RDWR))
                 return -EINVAL;
@@ -3319,14 +3319,6 @@ int journal_file_open(
                 }
         }
 
-        if (!m) {
-                m = mmap_cache_new();
-                if (!m) {
-                        r = -ENOMEM;
-                        goto fail;
-                }
-        }
-
         if (fname) {
                 f->path = strdup(fname);
                 if (!f->path) {
@@ -3368,17 +3360,12 @@ int journal_file_open(
                         goto fail;
         }
 
-        /* On success this incs refcnt on *m, which mmap_cache_fd_free() will dec. */
-        f->cache_fd = mmap_cache_add_fd(m, f->fd, prot_from_flags(flags));
+        f->cache_fd = mmap_cache_add_fd(mmap_cache, f->fd, prot_from_flags(flags));
         if (!f->cache_fd) {
                 r = -ENOMEM;
                 goto fail;
         }
 
-        /* If we created *m just for this file, unref *m so only f->cache_fd's ref remains */
-        if (!mmap_cache)
-                (void) mmap_cache_unref(m);
-
         r = journal_file_fstat(f);
         if (r < 0)
                 goto fail;