Adding upstream version 241.upstream/241upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3908 insertions, 0 deletions

diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c
new file mode 100644
index 0000000..56827f9
--- /dev/null
+++ b/src/journal/journal-file.c
@@ -0,0 +1,3908 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <pthread.h>
+#include <stddef.h>
+#include <sys/mman.h>
+#include <sys/statvfs.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+#include "sd-event.h"
+
+#include "alloc-util.h"
+#include "btrfs-util.h"
+#include "chattr-util.h"
+#include "compress.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "journal-authenticate.h"
+#include "journal-def.h"
+#include "journal-file.h"
+#include "lookup3.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "random-util.h"
+#include "set.h"
+#include "stat-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "xattr-util.h"
+
+#define DEFAULT_DATA_HASH_TABLE_SIZE (2047ULL*sizeof(HashItem))
+#define DEFAULT_FIELD_HASH_TABLE_SIZE (333ULL*sizeof(HashItem))
+
+#define DEFAULT_COMPRESS_THRESHOLD (512ULL)
+#define MIN_COMPRESS_THRESHOLD (8ULL)
+
+/* This is the minimum journal file size */
+#define JOURNAL_FILE_SIZE_MIN (512ULL*1024ULL)                 /* 512 KiB */
+
+/* These are the lower and upper bounds if we deduce the max_use value
+ * from the file system size */
+#define DEFAULT_MAX_USE_LOWER (1ULL*1024ULL*1024ULL)           /* 1 MiB */
+#define DEFAULT_MAX_USE_UPPER (4ULL*1024ULL*1024ULL*1024ULL)   /* 4 GiB */
+
+/* This is the default minimal use limit, how much we'll use even if keep_free suggests otherwise. */
+#define DEFAULT_MIN_USE (1ULL*1024ULL*1024ULL)                 /* 1 MiB */
+
+/* This is the upper bound if we deduce max_size from max_use */
+#define DEFAULT_MAX_SIZE_UPPER (128ULL*1024ULL*1024ULL)        /* 128 MiB */
+
+/* This is the upper bound if we deduce the keep_free value from the
+ * file system size */
+#define DEFAULT_KEEP_FREE_UPPER (4ULL*1024ULL*1024ULL*1024ULL) /* 4 GiB */
+
+/* This is the keep_free value when we can't determine the system
+ * size */
+#define DEFAULT_KEEP_FREE (1024ULL*1024ULL)                    /* 1 MB */
+
+/* This is the default maximum number of journal files to keep around. */
+#define DEFAULT_N_MAX_FILES (100)
+
+/* n_data was the first entry we added after the initial file format design */
+#define HEADER_SIZE_MIN ALIGN64(offsetof(Header, n_data))
+
+/* How many entries to keep in the entry array chain cache at max */
+#define CHAIN_CACHE_MAX 20
+
+/* How much to increase the journal file size at once each time we allocate something new. */
+#define FILE_SIZE_INCREASE (8ULL*1024ULL*1024ULL)              /* 8MB */
+
+/* Reread fstat() of the file for detecting deletions at least this often */
+#define LAST_STAT_REFRESH_USEC (5*USEC_PER_SEC)
+
+/* The mmap context to use for the header we pick as one above the last defined typed */
+#define CONTEXT_HEADER _OBJECT_TYPE_MAX
+
+#ifdef __clang__
+#  pragma GCC diagnostic ignored "-Waddress-of-packed-member"
+#endif
+
+/* This may be called from a separate thread to prevent blocking the caller for the duration of fsync().
+ * As a result we use atomic operations on f->offline_state for inter-thread communications with
+ * journal_file_set_offline() and journal_file_set_online(). */
+static void journal_file_set_offline_internal(JournalFile *f) {
+        assert(f);
+        assert(f->fd >= 0);
+        assert(f->header);
+
+        for (;;) {
+                switch (f->offline_state) {
+                case OFFLINE_CANCEL:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_CANCEL, OFFLINE_DONE))
+                                continue;
+                        return;
+
+                case OFFLINE_AGAIN_FROM_SYNCING:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_AGAIN_FROM_SYNCING, OFFLINE_SYNCING))
+                                continue;
+                        break;
+
+                case OFFLINE_AGAIN_FROM_OFFLINING:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_AGAIN_FROM_OFFLINING, OFFLINE_SYNCING))
+                                continue;
+                        break;
+
+                case OFFLINE_SYNCING:
+                        (void) fsync(f->fd);
+
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_SYNCING, OFFLINE_OFFLINING))
+                                continue;
+
+                        f->header->state = f->archive ? STATE_ARCHIVED : STATE_OFFLINE;
+                        (void) fsync(f->fd);
+                        break;
+
+                case OFFLINE_OFFLINING:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_OFFLINING, OFFLINE_DONE))
+                                continue;
+                        _fallthrough_;
+                case OFFLINE_DONE:
+                        return;
+
+                case OFFLINE_JOINED:
+                        log_debug("OFFLINE_JOINED unexpected offline state for journal_file_set_offline_internal()");
+                        return;
+                }
+        }
+}
+
+static void * journal_file_set_offline_thread(void *arg) {
+        JournalFile *f = arg;
+
+        (void) pthread_setname_np(pthread_self(), "journal-offline");
+
+        journal_file_set_offline_internal(f);
+
+        return NULL;
+}
+
+static int journal_file_set_offline_thread_join(JournalFile *f) {
+        int r;
+
+        assert(f);
+
+        if (f->offline_state == OFFLINE_JOINED)
+                return 0;
+
+        r = pthread_join(f->offline_thread, NULL);
+        if (r)
+                return -r;
+
+        f->offline_state = OFFLINE_JOINED;
+
+        if (mmap_cache_got_sigbus(f->mmap, f->cache_fd))
+                return -EIO;
+
+        return 0;
+}
+
+/* Trigger a restart if the offline thread is mid-flight in a restartable state. */
+static bool journal_file_set_offline_try_restart(JournalFile *f) {
+        for (;;) {
+                switch (f->offline_state) {
+                case OFFLINE_AGAIN_FROM_SYNCING:
+                case OFFLINE_AGAIN_FROM_OFFLINING:
+                        return true;
+
+                case OFFLINE_CANCEL:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_CANCEL, OFFLINE_AGAIN_FROM_SYNCING))
+                                continue;
+                        return true;
+
+                case OFFLINE_SYNCING:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_SYNCING, OFFLINE_AGAIN_FROM_SYNCING))
+                                continue;
+                        return true;
+
+                case OFFLINE_OFFLINING:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_OFFLINING, OFFLINE_AGAIN_FROM_OFFLINING))
+                                continue;
+                        return true;
+
+                default:
+                        return false;
+                }
+        }
+}
+
+/* Sets a journal offline.
+ *
+ * If wait is false then an offline is dispatched in a separate thread for a
+ * subsequent journal_file_set_offline() or journal_file_set_online() of the
+ * same journal to synchronize with.
+ *
+ * If wait is true, then either an existing offline thread will be restarted
+ * and joined, or if none exists the offline is simply performed in this
+ * context without involving another thread.
+ */
+int journal_file_set_offline(JournalFile *f, bool wait) {
+        bool restarted;
+        int r;
+
+        assert(f);
+
+        if (!f->writable)
+                return -EPERM;
+
+        if (f->fd < 0 || !f->header)
+                return -EINVAL;
+
+        /* An offlining journal is implicitly online and may modify f->header->state,
+         * we must also join any potentially lingering offline thread when not online. */
+        if (!journal_file_is_offlining(f) && f->header->state != STATE_ONLINE)
+                return journal_file_set_offline_thread_join(f);
+
+        /* Restart an in-flight offline thread and wait if needed, or join a lingering done one. */
+        restarted = journal_file_set_offline_try_restart(f);
+        if ((restarted && wait) || !restarted) {
+                r = journal_file_set_offline_thread_join(f);
+                if (r < 0)
+                        return r;
+        }
+
+        if (restarted)
+                return 0;
+
+        /* Initiate a new offline. */
+        f->offline_state = OFFLINE_SYNCING;
+
+        if (wait) /* Without using a thread if waiting. */
+                journal_file_set_offline_internal(f);
+        else {
+                sigset_t ss, saved_ss;
+                int k;
+
+                assert_se(sigfillset(&ss) >= 0);
+
+                r = pthread_sigmask(SIG_BLOCK, &ss, &saved_ss);
+                if (r > 0)
+                        return -r;
+
+                r = pthread_create(&f->offline_thread, NULL, journal_file_set_offline_thread, f);
+
+                k = pthread_sigmask(SIG_SETMASK, &saved_ss, NULL);
+                if (r > 0) {
+                        f->offline_state = OFFLINE_JOINED;
+                        return -r;
+                }
+                if (k > 0)
+                        return -k;
+        }
+
+        return 0;
+}
+
+static int journal_file_set_online(JournalFile *f) {
+        bool wait = true;
+
+        assert(f);
+
+        if (!f->writable)
+                return -EPERM;
+
+        if (f->fd < 0 || !f->header)
+                return -EINVAL;
+
+        while (wait) {
+                switch (f->offline_state) {
+                case OFFLINE_JOINED:
+                        /* No offline thread, no need to wait. */
+                        wait = false;
+                        break;
+
+                case OFFLINE_SYNCING:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_SYNCING, OFFLINE_CANCEL))
+                                continue;
+                        /* Canceled syncing prior to offlining, no need to wait. */
+                        wait = false;
+                        break;
+
+                case OFFLINE_AGAIN_FROM_SYNCING:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_AGAIN_FROM_SYNCING, OFFLINE_CANCEL))
+                                continue;
+                        /* Canceled restart from syncing, no need to wait. */
+                        wait = false;
+                        break;
+
+                case OFFLINE_AGAIN_FROM_OFFLINING:
+                        if (!__sync_bool_compare_and_swap(&f->offline_state, OFFLINE_AGAIN_FROM_OFFLINING, OFFLINE_CANCEL))
+                                continue;
+                        /* Canceled restart from offlining, must wait for offlining to complete however. */
+                        _fallthrough_;
+                default: {
+                        int r;
+
+                        r = journal_file_set_offline_thread_join(f);
+                        if (r < 0)
+                                return r;
+
+                        wait = false;
+                        break;
+                }
+                }
+        }
+
+        if (mmap_cache_got_sigbus(f->mmap, f->cache_fd))
+                return -EIO;
+
+        switch (f->header->state) {
+                case STATE_ONLINE:
+                        return 0;
+
+                case STATE_OFFLINE:
+                        f->header->state = STATE_ONLINE;
+                        (void) fsync(f->fd);
+                        return 0;
+
+                default:
+                        return -EINVAL;
+        }
+}
+
+bool journal_file_is_offlining(JournalFile *f) {
+        assert(f);
+
+        __sync_synchronize();
+
+        if (IN_SET(f->offline_state, OFFLINE_DONE, OFFLINE_JOINED))
+                return false;
+
+        return true;
+}
+
+JournalFile* journal_file_close(JournalFile *f) {
+        assert(f);
+
+#if HAVE_GCRYPT
+        /* Write the final tag */
+        if (f->seal && f->writable) {
+                int r;
+
+                r = journal_file_append_tag(f);
+                if (r < 0)
+                        log_error_errno(r, "Failed to append tag when closing journal: %m");
+        }
+#endif
+
+        if (f->post_change_timer) {
+                if (sd_event_source_get_enabled(f->post_change_timer, NULL) > 0)
+                        journal_file_post_change(f);
+
+                (void) sd_event_source_set_enabled(f->post_change_timer, SD_EVENT_OFF);
+                sd_event_source_unref(f->post_change_timer);
+        }
+
+        journal_file_set_offline(f, true);
+
+        if (f->mmap && f->cache_fd)
+                mmap_cache_free_fd(f->mmap, f->cache_fd);
+
+        if (f->fd >= 0 && f->defrag_on_close) {
+
+                /* Be friendly to btrfs: turn COW back on again now,
+                 * and defragment the file. We won't write to the file
+                 * ever again, hence remove all fragmentation, and
+                 * reenable all the good bits COW usually provides
+                 * (such as data checksumming). */
+
+                (void) chattr_fd(f->fd, 0, FS_NOCOW_FL, NULL);
+                (void) btrfs_defrag_fd(f->fd);
+        }
+
+        if (f->close_fd)
+                safe_close(f->fd);
+        free(f->path);
+
+        mmap_cache_unref(f->mmap);
+
+        ordered_hashmap_free_free(f->chain_cache);
+
+#if HAVE_XZ || HAVE_LZ4
+        free(f->compress_buffer);
+#endif
+
+#if HAVE_GCRYPT
+        if (f->fss_file)
+                munmap(f->fss_file, PAGE_ALIGN(f->fss_file_size));
+        else
+                free(f->fsprg_state);
+
+        free(f->fsprg_seed);
+
+        if (f->hmac)
+                gcry_md_close(f->hmac);
+#endif
+
+        return mfree(f);
+}
+
+static int journal_file_init_header(JournalFile *f, JournalFile *template) {
+        Header h = {};
+        ssize_t k;
+        int r;
+
+        assert(f);
+
+        memcpy(h.signature, HEADER_SIGNATURE, 8);
+        h.header_size = htole64(ALIGN64(sizeof(h)));
+
+        h.incompatible_flags |= htole32(
+                f->compress_xz * HEADER_INCOMPATIBLE_COMPRESSED_XZ |
+                f->compress_lz4 * HEADER_INCOMPATIBLE_COMPRESSED_LZ4);
+
+        h.compatible_flags = htole32(
+                f->seal * HEADER_COMPATIBLE_SEALED);
+
+        r = sd_id128_randomize(&h.file_id);
+        if (r < 0)
+                return r;
+
+        if (template) {
+                h.seqnum_id = template->header->seqnum_id;
+                h.tail_entry_seqnum = template->header->tail_entry_seqnum;
+        } else
+                h.seqnum_id = h.file_id;
+
+        k = pwrite(f->fd, &h, sizeof(h), 0);
+        if (k < 0)
+                return -errno;
+
+        if (k != sizeof(h))
+                return -EIO;
+
+        return 0;
+}
+
+static int journal_file_refresh_header(JournalFile *f) {
+        sd_id128_t boot_id;
+        int r;
+
+        assert(f);
+        assert(f->header);
+
+        r = sd_id128_get_machine(&f->header->machine_id);
+        if (IN_SET(r, -ENOENT, -ENOMEDIUM))
+                /* We don't have a machine-id, let's continue without */
+                zero(f->header->machine_id);
+        else if (r < 0)
+                return r;
+
+        r = sd_id128_get_boot(&boot_id);
+        if (r < 0)
+                return r;
+
+        f->header->boot_id = boot_id;
+
+        r = journal_file_set_online(f);
+
+        /* Sync the online state to disk */
+        (void) fsync(f->fd);
+
+        /* We likely just created a new file, also sync the directory this file is located in. */
+        (void) fsync_directory_of_file(f->fd);
+
+        return r;
+}
+
+static bool warn_wrong_flags(const JournalFile *f, bool compatible) {
+        const uint32_t any = compatible ? HEADER_COMPATIBLE_ANY : HEADER_INCOMPATIBLE_ANY,
+                supported = compatible ? HEADER_COMPATIBLE_SUPPORTED : HEADER_INCOMPATIBLE_SUPPORTED;
+        const char *type = compatible ? "compatible" : "incompatible";
+        uint32_t flags;
+
+        flags = le32toh(compatible ? f->header->compatible_flags : f->header->incompatible_flags);
+
+        if (flags & ~supported) {
+                if (flags & ~any)
+                        log_debug("Journal file %s has unknown %s flags 0x%"PRIx32,
+                                  f->path, type, flags & ~any);
+                flags = (flags & any) & ~supported;
+                if (flags) {
+                        const char* strv[3];
+                        unsigned n = 0;
+                        _cleanup_free_ char *t = NULL;
+
+                        if (compatible && (flags & HEADER_COMPATIBLE_SEALED))
+                                strv[n++] = "sealed";
+                        if (!compatible && (flags & HEADER_INCOMPATIBLE_COMPRESSED_XZ))
+                                strv[n++] = "xz-compressed";
+                        if (!compatible && (flags & HEADER_INCOMPATIBLE_COMPRESSED_LZ4))
+                                strv[n++] = "lz4-compressed";
+                        strv[n] = NULL;
+                        assert(n < ELEMENTSOF(strv));
+
+                        t = strv_join((char**) strv, ", ");
+                        log_debug("Journal file %s uses %s %s %s disabled at compilation time.",
+                                  f->path, type, n > 1 ? "flags" : "flag", strnull(t));
+                }
+                return true;
+        }
+
+        return false;
+}
+
+static int journal_file_verify_header(JournalFile *f) {
+        uint64_t arena_size, header_size;
+
+        assert(f);
+        assert(f->header);
+
+        if (memcmp(f->header->signature, HEADER_SIGNATURE, 8))
+                return -EBADMSG;
+
+        /* In both read and write mode we refuse to open files with incompatible
+         * flags we don't know. */
+        if (warn_wrong_flags(f, false))
+                return -EPROTONOSUPPORT;
+
+        /* When open for writing we refuse to open files with compatible flags, too. */
+        if (f->writable && warn_wrong_flags(f, true))
+                return -EPROTONOSUPPORT;
+
+        if (f->header->state >= _STATE_MAX)
+                return -EBADMSG;
+
+        header_size = le64toh(f->header->header_size);
+
+        /* The first addition was n_data, so check that we are at least this large */
+        if (header_size < HEADER_SIZE_MIN)
+                return -EBADMSG;
+
+        if (JOURNAL_HEADER_SEALED(f->header) && !JOURNAL_HEADER_CONTAINS(f->header, n_entry_arrays))
+                return -EBADMSG;
+
+        arena_size = le64toh(f->header->arena_size);
+
+        if (UINT64_MAX - header_size < arena_size || header_size + arena_size > (uint64_t) f->last_stat.st_size)
+                return -ENODATA;
+
+        if (le64toh(f->header->tail_object_offset) > header_size + arena_size)
+                return -ENODATA;
+
+        if (!VALID64(le64toh(f->header->data_hash_table_offset)) ||
+            !VALID64(le64toh(f->header->field_hash_table_offset)) ||
+            !VALID64(le64toh(f->header->tail_object_offset)) ||
+            !VALID64(le64toh(f->header->entry_array_offset)))
+                return -ENODATA;
+
+        if (f->writable) {
+                sd_id128_t machine_id;
+                uint8_t state;
+                int r;
+
+                r = sd_id128_get_machine(&machine_id);
+                if (r < 0)
+                        return r;
+
+                if (!sd_id128_equal(machine_id, f->header->machine_id))
+                        return -EHOSTDOWN;
+
+                state = f->header->state;
+
+                if (state == STATE_ARCHIVED)
+                        return -ESHUTDOWN; /* Already archived */
+                else if (state == STATE_ONLINE)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBUSY),
+                                               "Journal file %s is already online. Assuming unclean closing.",
+                                               f->path);
+                else if (state != STATE_OFFLINE)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBUSY),
+                                               "Journal file %s has unknown state %i.",
+                                               f->path, state);
+
+                if (f->header->field_hash_table_size == 0 || f->header->data_hash_table_size == 0)
+                        return -EBADMSG;
+
+                /* Don't permit appending to files from the future. Because otherwise the realtime timestamps wouldn't
+                 * be strictly ordered in the entries in the file anymore, and we can't have that since it breaks
+                 * bisection. */
+                if (le64toh(f->header->tail_entry_realtime) > now(CLOCK_REALTIME))
+                        return log_debug_errno(SYNTHETIC_ERRNO(ETXTBSY),
+                                               "Journal file %s is from the future, refusing to append new data to it that'd be older.",
+                                               f->path);
+        }
+
+        f->compress_xz = JOURNAL_HEADER_COMPRESSED_XZ(f->header);
+        f->compress_lz4 = JOURNAL_HEADER_COMPRESSED_LZ4(f->header);
+
+        f->seal = JOURNAL_HEADER_SEALED(f->header);
+
+        return 0;
+}
+
+static int journal_file_fstat(JournalFile *f) {
+        int r;
+
+        assert(f);
+        assert(f->fd >= 0);
+
+        if (fstat(f->fd, &f->last_stat) < 0)
+                return -errno;
+
+        f->last_stat_usec = now(CLOCK_MONOTONIC);
+
+        /* Refuse dealing with with files that aren't regular */
+        r = stat_verify_regular(&f->last_stat);
+        if (r < 0)
+                return r;
+
+        /* Refuse appending to files that are already deleted */
+        if (f->last_stat.st_nlink <= 0)
+                return -EIDRM;
+
+        return 0;
+}
+
+static int journal_file_allocate(JournalFile *f, uint64_t offset, uint64_t size) {
+        uint64_t old_size, new_size;
+        int r;
+
+        assert(f);
+        assert(f->header);
+
+        /* We assume that this file is not sparse, and we know that
+         * for sure, since we always call posix_fallocate()
+         * ourselves */
+
+        if (mmap_cache_got_sigbus(f->mmap, f->cache_fd))
+                return -EIO;
+
+        old_size =
+                le64toh(f->header->header_size) +
+                le64toh(f->header->arena_size);
+
+        new_size = PAGE_ALIGN(offset + size);
+        if (new_size < le64toh(f->header->header_size))
+                new_size = le64toh(f->header->header_size);
+
+        if (new_size <= old_size) {
+
+                /* We already pre-allocated enough space, but before
+                 * we write to it, let's check with fstat() if the
+                 * file got deleted, in order make sure we don't throw
+                 * away the data immediately. Don't check fstat() for
+                 * all writes though, but only once ever 10s. */
+
+                if (f->last_stat_usec + LAST_STAT_REFRESH_USEC > now(CLOCK_MONOTONIC))
+                        return 0;
+
+                return journal_file_fstat(f);
+        }
+
+        /* Allocate more space. */
+
+        if (f->metrics.max_size > 0 && new_size > f->metrics.max_size)
+                return -E2BIG;
+
+        if (new_size > f->metrics.min_size && f->metrics.keep_free > 0) {
+                struct statvfs svfs;
+
+                if (fstatvfs(f->fd, &svfs) >= 0) {
+                        uint64_t available;
+
+                        available = LESS_BY((uint64_t) svfs.f_bfree * (uint64_t) svfs.f_bsize, f->metrics.keep_free);
+
+                        if (new_size - old_size > available)
+                                return -E2BIG;
+                }
+        }
+
+        /* Increase by larger blocks at once */
+        new_size = DIV_ROUND_UP(new_size, FILE_SIZE_INCREASE) * FILE_SIZE_INCREASE;
+        if (f->metrics.max_size > 0 && new_size > f->metrics.max_size)
+                new_size = f->metrics.max_size;
+
+        /* Note that the glibc fallocate() fallback is very
+           inefficient, hence we try to minimize the allocation area
+           as we can. */
+        r = posix_fallocate(f->fd, old_size, new_size - old_size);
+        if (r != 0)
+                return -r;
+
+        f->header->arena_size = htole64(new_size - le64toh(f->header->header_size));
+
+        return journal_file_fstat(f);
+}
+
+static unsigned type_to_context(ObjectType type) {
+        /* One context for each type, plus one catch-all for the rest */
+        assert_cc(_OBJECT_TYPE_MAX <= MMAP_CACHE_MAX_CONTEXTS);
+        assert_cc(CONTEXT_HEADER < MMAP_CACHE_MAX_CONTEXTS);
+        return type > OBJECT_UNUSED && type < _OBJECT_TYPE_MAX ? type : 0;
+}
+
+static int journal_file_move_to(JournalFile *f, ObjectType type, bool keep_always, uint64_t offset, uint64_t size, void **ret, size_t *ret_size) {
+        int r;
+
+        assert(f);
+        assert(ret);
+
+        if (size <= 0)
+                return -EINVAL;
+
+        /* Avoid SIGBUS on invalid accesses */
+        if (offset + size > (uint64_t) f->last_stat.st_size) {
+                /* Hmm, out of range? Let's refresh the fstat() data
+                 * first, before we trust that check. */
+
+                r = journal_file_fstat(f);
+                if (r < 0)
+                        return r;
+
+                if (offset + size > (uint64_t) f->last_stat.st_size)
+                        return -EADDRNOTAVAIL;
+        }
+
+        return mmap_cache_get(f->mmap, f->cache_fd, f->prot, type_to_context(type), keep_always, offset, size, &f->last_stat, ret, ret_size);
+}
+
+static uint64_t minimum_header_size(Object *o) {
+
+        static const uint64_t table[] = {
+                [OBJECT_DATA] = sizeof(DataObject),
+                [OBJECT_FIELD] = sizeof(FieldObject),
+                [OBJECT_ENTRY] = sizeof(EntryObject),
+                [OBJECT_DATA_HASH_TABLE] = sizeof(HashTableObject),
+                [OBJECT_FIELD_HASH_TABLE] = sizeof(HashTableObject),
+                [OBJECT_ENTRY_ARRAY] = sizeof(EntryArrayObject),
+                [OBJECT_TAG] = sizeof(TagObject),
+        };
+
+        if (o->object.type >= ELEMENTSOF(table) || table[o->object.type] <= 0)
+                return sizeof(ObjectHeader);
+
+        return table[o->object.type];
+}
+
+/* Lightweight object checks. We want this to be fast, so that we won't
+ * slowdown every journal_file_move_to_object() call too much. */
+static int journal_file_check_object(JournalFile *f, uint64_t offset, Object *o) {
+        assert(f);
+        assert(o);
+
+        switch (o->object.type) {
+
+        case OBJECT_DATA: {
+                if ((le64toh(o->data.entry_offset) == 0) ^ (le64toh(o->data.n_entries) == 0))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Bad n_entries: %" PRIu64 ": %" PRIu64,
+                                               le64toh(o->data.n_entries),
+                                               offset);
+
+                if (le64toh(o->object.size) - offsetof(DataObject, payload) <= 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Bad object size (<= %zu): %" PRIu64 ": %" PRIu64,
+                                               offsetof(DataObject, payload),
+                                               le64toh(o->object.size),
+                                               offset);
+
+                if (!VALID64(le64toh(o->data.next_hash_offset)) ||
+                    !VALID64(le64toh(o->data.next_field_offset)) ||
+                    !VALID64(le64toh(o->data.entry_offset)) ||
+                    !VALID64(le64toh(o->data.entry_array_offset)))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid offset, next_hash_offset=" OFSfmt ", next_field_offset=" OFSfmt ", entry_offset=" OFSfmt ", entry_array_offset=" OFSfmt ": %" PRIu64,
+                                               le64toh(o->data.next_hash_offset),
+                                               le64toh(o->data.next_field_offset),
+                                               le64toh(o->data.entry_offset),
+                                               le64toh(o->data.entry_array_offset),
+                                               offset);
+
+                break;
+        }
+
+        case OBJECT_FIELD:
+                if (le64toh(o->object.size) - offsetof(FieldObject, payload) <= 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Bad field size (<= %zu): %" PRIu64 ": %" PRIu64,
+                                               offsetof(FieldObject, payload),
+                                               le64toh(o->object.size),
+                                               offset);
+
+                if (!VALID64(le64toh(o->field.next_hash_offset)) ||
+                    !VALID64(le64toh(o->field.head_data_offset)))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid offset, next_hash_offset=" OFSfmt ", head_data_offset=" OFSfmt ": %" PRIu64,
+                                               le64toh(o->field.next_hash_offset),
+                                               le64toh(o->field.head_data_offset),
+                                               offset);
+                break;
+
+        case OBJECT_ENTRY:
+                if ((le64toh(o->object.size) - offsetof(EntryObject, items)) % sizeof(EntryItem) != 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Bad entry size (<= %zu): %" PRIu64 ": %" PRIu64,
+                                               offsetof(EntryObject, items),
+                                               le64toh(o->object.size),
+                                               offset);
+
+                if ((le64toh(o->object.size) - offsetof(EntryObject, items)) / sizeof(EntryItem) <= 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid number items in entry: %" PRIu64 ": %" PRIu64,
+                                               (le64toh(o->object.size) - offsetof(EntryObject, items)) / sizeof(EntryItem),
+                                               offset);
+
+                if (le64toh(o->entry.seqnum) <= 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid entry seqnum: %" PRIx64 ": %" PRIu64,
+                                               le64toh(o->entry.seqnum),
+                                               offset);
+
+                if (!VALID_REALTIME(le64toh(o->entry.realtime)))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid entry realtime timestamp: %" PRIu64 ": %" PRIu64,
+                                               le64toh(o->entry.realtime),
+                                               offset);
+
+                if (!VALID_MONOTONIC(le64toh(o->entry.monotonic)))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid entry monotonic timestamp: %" PRIu64 ": %" PRIu64,
+                                               le64toh(o->entry.monotonic),
+                                               offset);
+
+                break;
+
+        case OBJECT_DATA_HASH_TABLE:
+        case OBJECT_FIELD_HASH_TABLE:
+                if ((le64toh(o->object.size) - offsetof(HashTableObject, items)) % sizeof(HashItem) != 0 ||
+                    (le64toh(o->object.size) - offsetof(HashTableObject, items)) / sizeof(HashItem) <= 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid %s hash table size: %" PRIu64 ": %" PRIu64,
+                                               o->object.type == OBJECT_DATA_HASH_TABLE ? "data" : "field",
+                                               le64toh(o->object.size),
+                                               offset);
+
+                break;
+
+        case OBJECT_ENTRY_ARRAY:
+                if ((le64toh(o->object.size) - offsetof(EntryArrayObject, items)) % sizeof(le64_t) != 0 ||
+                    (le64toh(o->object.size) - offsetof(EntryArrayObject, items)) / sizeof(le64_t) <= 0)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid object entry array size: %" PRIu64 ": %" PRIu64,
+                                               le64toh(o->object.size),
+                                               offset);
+
+                if (!VALID64(le64toh(o->entry_array.next_entry_array_offset)))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid object entry array next_entry_array_offset: " OFSfmt ": %" PRIu64,
+                                               le64toh(o->entry_array.next_entry_array_offset),
+                                               offset);
+
+                break;
+
+        case OBJECT_TAG:
+                if (le64toh(o->object.size) != sizeof(TagObject))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid object tag size: %" PRIu64 ": %" PRIu64,
+                                               le64toh(o->object.size),
+                                               offset);
+
+                if (!VALID_EPOCH(le64toh(o->tag.epoch)))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid object tag epoch: %" PRIu64 ": %" PRIu64,
+                                               le64toh(o->tag.epoch), offset);
+
+                break;
+        }
+
+        return 0;
+}
+
+int journal_file_move_to_object(JournalFile *f, ObjectType type, uint64_t offset, Object **ret) {
+        int r;
+        void *t;
+        size_t tsize;
+        Object *o;
+        uint64_t s;
+
+        assert(f);
+        assert(ret);
+
+        /* Objects may only be located at multiple of 64 bit */
+        if (!VALID64(offset))
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "Attempt to move to object at non-64bit boundary: %" PRIu64,
+                                       offset);
+
+        /* Object may not be located in the file header */
+        if (offset < le64toh(f->header->header_size))
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "Attempt to move to object located in file header: %" PRIu64,
+                                       offset);
+
+        r = journal_file_move_to(f, type, false, offset, sizeof(ObjectHeader), &t, &tsize);
+        if (r < 0)
+                return r;
+
+        o = (Object*) t;
+        s = le64toh(o->object.size);
+
+        if (s == 0)
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "Attempt to move to uninitialized object: %" PRIu64,
+                                       offset);
+        if (s < sizeof(ObjectHeader))
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "Attempt to move to overly short object: %" PRIu64,
+                                       offset);
+
+        if (o->object.type <= OBJECT_UNUSED)
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "Attempt to move to object with invalid type: %" PRIu64,
+                                       offset);
+
+        if (s < minimum_header_size(o))
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "Attempt to move to truncated object: %" PRIu64,
+                                       offset);
+
+        if (type > OBJECT_UNUSED && o->object.type != type)
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "Attempt to move to object of unexpected type: %" PRIu64,
+                                       offset);
+
+        if (s > tsize) {
+                r = journal_file_move_to(f, type, false, offset, s, &t, NULL);
+                if (r < 0)
+                        return r;
+
+                o = (Object*) t;
+        }
+
+        r = journal_file_check_object(f, offset, o);
+        if (r < 0)
+                return r;
+
+        *ret = o;
+        return 0;
+}
+
+static uint64_t journal_file_entry_seqnum(JournalFile *f, uint64_t *seqnum) {
+        uint64_t r;
+
+        assert(f);
+        assert(f->header);
+
+        r = le64toh(f->header->tail_entry_seqnum) + 1;
+
+        if (seqnum) {
+                /* If an external seqnum counter was passed, we update
+                 * both the local and the external one, and set it to
+                 * the maximum of both */
+
+                if (*seqnum + 1 > r)
+                        r = *seqnum + 1;
+
+                *seqnum = r;
+        }
+
+        f->header->tail_entry_seqnum = htole64(r);
+
+        if (f->header->head_entry_seqnum == 0)
+                f->header->head_entry_seqnum = htole64(r);
+
+        return r;
+}
+
+int journal_file_append_object(JournalFile *f, ObjectType type, uint64_t size, Object **ret, uint64_t *offset) {
+        int r;
+        uint64_t p;
+        Object *tail, *o;
+        void *t;
+
+        assert(f);
+        assert(f->header);
+        assert(type > OBJECT_UNUSED && type < _OBJECT_TYPE_MAX);
+        assert(size >= sizeof(ObjectHeader));
+        assert(offset);
+        assert(ret);
+
+        r = journal_file_set_online(f);
+        if (r < 0)
+                return r;
+
+        p = le64toh(f->header->tail_object_offset);
+        if (p == 0)
+                p = le64toh(f->header->header_size);
+        else {
+                r = journal_file_move_to_object(f, OBJECT_UNUSED, p, &tail);
+                if (r < 0)
+                        return r;
+
+                p += ALIGN64(le64toh(tail->object.size));
+        }
+
+        r = journal_file_allocate(f, p, size);
+        if (r < 0)
+                return r;
+
+        r = journal_file_move_to(f, type, false, p, size, &t, NULL);
+        if (r < 0)
+                return r;
+
+        o = (Object*) t;
+
+        zero(o->object);
+        o->object.type = type;
+        o->object.size = htole64(size);
+
+        f->header->tail_object_offset = htole64(p);
+        f->header->n_objects = htole64(le64toh(f->header->n_objects) + 1);
+
+        *ret = o;
+        *offset = p;
+
+        return 0;
+}
+
+static int journal_file_setup_data_hash_table(JournalFile *f) {
+        uint64_t s, p;
+        Object *o;
+        int r;
+
+        assert(f);
+        assert(f->header);
+
+        /* We estimate that we need 1 hash table entry per 768 bytes
+           of journal file and we want to make sure we never get
+           beyond 75% fill level. Calculate the hash table size for
+           the maximum file size based on these metrics. */
+
+        s = (f->metrics.max_size * 4 / 768 / 3) * sizeof(HashItem);
+        if (s < DEFAULT_DATA_HASH_TABLE_SIZE)
+                s = DEFAULT_DATA_HASH_TABLE_SIZE;
+
+        log_debug("Reserving %"PRIu64" entries in hash table.", s / sizeof(HashItem));
+
+        r = journal_file_append_object(f,
+                                       OBJECT_DATA_HASH_TABLE,
+                                       offsetof(Object, hash_table.items) + s,
+                                       &o, &p);
+        if (r < 0)
+                return r;
+
+        memzero(o->hash_table.items, s);
+
+        f->header->data_hash_table_offset = htole64(p + offsetof(Object, hash_table.items));
+        f->header->data_hash_table_size = htole64(s);
+
+        return 0;
+}
+
+static int journal_file_setup_field_hash_table(JournalFile *f) {
+        uint64_t s, p;
+        Object *o;
+        int r;
+
+        assert(f);
+        assert(f->header);
+
+        /* We use a fixed size hash table for the fields as this
+         * number should grow very slowly only */
+
+        s = DEFAULT_FIELD_HASH_TABLE_SIZE;
+        r = journal_file_append_object(f,
+                                       OBJECT_FIELD_HASH_TABLE,
+                                       offsetof(Object, hash_table.items) + s,
+                                       &o, &p);
+        if (r < 0)
+                return r;
+
+        memzero(o->hash_table.items, s);
+
+        f->header->field_hash_table_offset = htole64(p + offsetof(Object, hash_table.items));
+        f->header->field_hash_table_size = htole64(s);
+
+        return 0;
+}
+
+int journal_file_map_data_hash_table(JournalFile *f) {
+        uint64_t s, p;
+        void *t;
+        int r;
+
+        assert(f);
+        assert(f->header);
+
+        if (f->data_hash_table)
+                return 0;
+
+        p = le64toh(f->header->data_hash_table_offset);
+        s = le64toh(f->header->data_hash_table_size);
+
+        r = journal_file_move_to(f,
+                                 OBJECT_DATA_HASH_TABLE,
+                                 true,
+                                 p, s,
+                                 &t, NULL);
+        if (r < 0)
+                return r;
+
+        f->data_hash_table = t;
+        return 0;
+}
+
+int journal_file_map_field_hash_table(JournalFile *f) {
+        uint64_t s, p;
+        void *t;
+        int r;
+
+        assert(f);
+        assert(f->header);
+
+        if (f->field_hash_table)
+                return 0;
+
+        p = le64toh(f->header->field_hash_table_offset);
+        s = le64toh(f->header->field_hash_table_size);
+
+        r = journal_file_move_to(f,
+                                 OBJECT_FIELD_HASH_TABLE,
+                                 true,
+                                 p, s,
+                                 &t, NULL);
+        if (r < 0)
+                return r;
+
+        f->field_hash_table = t;
+        return 0;
+}
+
+static int journal_file_link_field(
+                JournalFile *f,
+                Object *o,
+                uint64_t offset,
+                uint64_t hash) {
+
+        uint64_t p, h, m;
+        int r;
+
+        assert(f);
+        assert(f->header);
+        assert(f->field_hash_table);
+        assert(o);
+        assert(offset > 0);
+
+        if (o->object.type != OBJECT_FIELD)
+                return -EINVAL;
+
+        m = le64toh(f->header->field_hash_table_size) / sizeof(HashItem);
+        if (m <= 0)
+                return -EBADMSG;
+
+        /* This might alter the window we are looking at */
+        o->field.next_hash_offset = o->field.head_data_offset = 0;
+
+        h = hash % m;
+        p = le64toh(f->field_hash_table[h].tail_hash_offset);
+        if (p == 0)
+                f->field_hash_table[h].head_hash_offset = htole64(offset);
+        else {
+                r = journal_file_move_to_object(f, OBJECT_FIELD, p, &o);
+                if (r < 0)
+                        return r;
+
+                o->field.next_hash_offset = htole64(offset);
+        }
+
+        f->field_hash_table[h].tail_hash_offset = htole64(offset);
+
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_fields))
+                f->header->n_fields = htole64(le64toh(f->header->n_fields) + 1);
+
+        return 0;
+}
+
+static int journal_file_link_data(
+                JournalFile *f,
+                Object *o,
+                uint64_t offset,
+                uint64_t hash) {
+
+        uint64_t p, h, m;
+        int r;
+
+        assert(f);
+        assert(f->header);
+        assert(f->data_hash_table);
+        assert(o);
+        assert(offset > 0);
+
+        if (o->object.type != OBJECT_DATA)
+                return -EINVAL;
+
+        m = le64toh(f->header->data_hash_table_size) / sizeof(HashItem);
+        if (m <= 0)
+                return -EBADMSG;
+
+        /* This might alter the window we are looking at */
+        o->data.next_hash_offset = o->data.next_field_offset = 0;
+        o->data.entry_offset = o->data.entry_array_offset = 0;
+        o->data.n_entries = 0;
+
+        h = hash % m;
+        p = le64toh(f->data_hash_table[h].tail_hash_offset);
+        if (p == 0)
+                /* Only entry in the hash table is easy */
+                f->data_hash_table[h].head_hash_offset = htole64(offset);
+        else {
+                /* Move back to the previous data object, to patch in
+                 * pointer */
+
+                r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
+                if (r < 0)
+                        return r;
+
+                o->data.next_hash_offset = htole64(offset);
+        }
+
+        f->data_hash_table[h].tail_hash_offset = htole64(offset);
+
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_data))
+                f->header->n_data = htole64(le64toh(f->header->n_data) + 1);
+
+        return 0;
+}
+
+int journal_file_find_field_object_with_hash(
+                JournalFile *f,
+                const void *field, uint64_t size, uint64_t hash,
+                Object **ret, uint64_t *offset) {
+
+        uint64_t p, osize, h, m;
+        int r;
+
+        assert(f);
+        assert(f->header);
+        assert(field && size > 0);
+
+        /* If the field hash table is empty, we can't find anything */
+        if (le64toh(f->header->field_hash_table_size) <= 0)
+                return 0;
+
+        /* Map the field hash table, if it isn't mapped yet. */
+        r = journal_file_map_field_hash_table(f);
+        if (r < 0)
+                return r;
+
+        osize = offsetof(Object, field.payload) + size;
+
+        m = le64toh(f->header->field_hash_table_size) / sizeof(HashItem);
+        if (m <= 0)
+                return -EBADMSG;
+
+        h = hash % m;
+        p = le64toh(f->field_hash_table[h].head_hash_offset);
+
+        while (p > 0) {
+                Object *o;
+
+                r = journal_file_move_to_object(f, OBJECT_FIELD, p, &o);
+                if (r < 0)
+                        return r;
+
+                if (le64toh(o->field.hash) == hash &&
+                    le64toh(o->object.size) == osize &&
+                    memcmp(o->field.payload, field, size) == 0) {
+
+                        if (ret)
+                                *ret = o;
+                        if (offset)
+                                *offset = p;
+
+                        return 1;
+                }
+
+                p = le64toh(o->field.next_hash_offset);
+        }
+
+        return 0;
+}
+
+int journal_file_find_field_object(
+                JournalFile *f,
+                const void *field, uint64_t size,
+                Object **ret, uint64_t *offset) {
+
+        uint64_t hash;
+
+        assert(f);
+        assert(field && size > 0);
+
+        hash = hash64(field, size);
+
+        return journal_file_find_field_object_with_hash(f,
+                                                        field, size, hash,
+                                                        ret, offset);
+}
+
+int journal_file_find_data_object_with_hash(
+                JournalFile *f,
+                const void *data, uint64_t size, uint64_t hash,
+                Object **ret, uint64_t *offset) {
+
+        uint64_t p, osize, h, m;
+        int r;
+
+        assert(f);
+        assert(f->header);
+        assert(data || size == 0);
+
+        /* If there's no data hash table, then there's no entry. */
+        if (le64toh(f->header->data_hash_table_size) <= 0)
+                return 0;
+
+        /* Map the data hash table, if it isn't mapped yet. */
+        r = journal_file_map_data_hash_table(f);
+        if (r < 0)
+                return r;
+
+        osize = offsetof(Object, data.payload) + size;
+
+        m = le64toh(f->header->data_hash_table_size) / sizeof(HashItem);
+        if (m <= 0)
+                return -EBADMSG;
+
+        h = hash % m;
+        p = le64toh(f->data_hash_table[h].head_hash_offset);
+
+        while (p > 0) {
+                Object *o;
+
+                r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
+                if (r < 0)
+                        return r;
+
+                if (le64toh(o->data.hash) != hash)
+                        goto next;
+
+                if (o->object.flags & OBJECT_COMPRESSION_MASK) {
+#if HAVE_XZ || HAVE_LZ4
+                        uint64_t l;
+                        size_t rsize = 0;
+
+                        l = le64toh(o->object.size);
+                        if (l <= offsetof(Object, data.payload))
+                                return -EBADMSG;
+
+                        l -= offsetof(Object, data.payload);
+
+                        r = decompress_blob(o->object.flags & OBJECT_COMPRESSION_MASK,
+                                            o->data.payload, l, &f->compress_buffer, &f->compress_buffer_size, &rsize, 0);
+                        if (r < 0)
+                                return r;
+
+                        if (rsize == size &&
+                            memcmp(f->compress_buffer, data, size) == 0) {
+
+                                if (ret)
+                                        *ret = o;
+
+                                if (offset)
+                                        *offset = p;
+
+                                return 1;
+                        }
+#else
+                        return -EPROTONOSUPPORT;
+#endif
+                } else if (le64toh(o->object.size) == osize &&
+                           memcmp(o->data.payload, data, size) == 0) {
+
+                        if (ret)
+                                *ret = o;
+
+                        if (offset)
+                                *offset = p;
+
+                        return 1;
+                }
+
+        next:
+                p = le64toh(o->data.next_hash_offset);
+        }
+
+        return 0;
+}
+
+int journal_file_find_data_object(
+                JournalFile *f,
+                const void *data, uint64_t size,
+                Object **ret, uint64_t *offset) {
+
+        uint64_t hash;
+
+        assert(f);
+        assert(data || size == 0);
+
+        hash = hash64(data, size);
+
+        return journal_file_find_data_object_with_hash(f,
+                                                       data, size, hash,
+                                                       ret, offset);
+}
+
+static int journal_file_append_field(
+                JournalFile *f,
+                const void *field, uint64_t size,
+                Object **ret, uint64_t *offset) {
+
+        uint64_t hash, p;
+        uint64_t osize;
+        Object *o;
+        int r;
+
+        assert(f);
+        assert(field && size > 0);
+
+        hash = hash64(field, size);
+
+        r = journal_file_find_field_object_with_hash(f, field, size, hash, &o, &p);
+        if (r < 0)
+                return r;
+        else if (r > 0) {
+
+                if (ret)
+                        *ret = o;
+
+                if (offset)
+                        *offset = p;
+
+                return 0;
+        }
+
+        osize = offsetof(Object, field.payload) + size;
+        r = journal_file_append_object(f, OBJECT_FIELD, osize, &o, &p);
+        if (r < 0)
+                return r;
+
+        o->field.hash = htole64(hash);
+        memcpy(o->field.payload, field, size);
+
+        r = journal_file_link_field(f, o, p, hash);
+        if (r < 0)
+                return r;
+
+        /* The linking might have altered the window, so let's
+         * refresh our pointer */
+        r = journal_file_move_to_object(f, OBJECT_FIELD, p, &o);
+        if (r < 0)
+                return r;
+
+#if HAVE_GCRYPT
+        r = journal_file_hmac_put_object(f, OBJECT_FIELD, o, p);
+        if (r < 0)
+                return r;
+#endif
+
+        if (ret)
+                *ret = o;
+
+        if (offset)
+                *offset = p;
+
+        return 0;
+}
+
+static int journal_file_append_data(
+                JournalFile *f,
+                const void *data, uint64_t size,
+                Object **ret, uint64_t *offset) {
+
+        uint64_t hash, p;
+        uint64_t osize;
+        Object *o;
+        int r, compression = 0;
+        const void *eq;
+
+        assert(f);
+        assert(data || size == 0);
+
+        hash = hash64(data, size);
+
+        r = journal_file_find_data_object_with_hash(f, data, size, hash, &o, &p);
+        if (r < 0)
+                return r;
+        if (r > 0) {
+
+                if (ret)
+                        *ret = o;
+
+                if (offset)
+                        *offset = p;
+
+                return 0;
+        }
+
+        osize = offsetof(Object, data.payload) + size;
+        r = journal_file_append_object(f, OBJECT_DATA, osize, &o, &p);
+        if (r < 0)
+                return r;
+
+        o->data.hash = htole64(hash);
+
+#if HAVE_XZ || HAVE_LZ4
+        if (JOURNAL_FILE_COMPRESS(f) && size >= f->compress_threshold_bytes) {
+                size_t rsize = 0;
+
+                compression = compress_blob(data, size, o->data.payload, size - 1, &rsize);
+
+                if (compression >= 0) {
+                        o->object.size = htole64(offsetof(Object, data.payload) + rsize);
+                        o->object.flags |= compression;
+
+                        log_debug("Compressed data object %"PRIu64" -> %zu using %s",
+                                  size, rsize, object_compressed_to_string(compression));
+                } else
+                        /* Compression didn't work, we don't really care why, let's continue without compression */
+                        compression = 0;
+        }
+#endif
+
+        if (compression == 0)
+                memcpy_safe(o->data.payload, data, size);
+
+        r = journal_file_link_data(f, o, p, hash);
+        if (r < 0)
+                return r;
+
+#if HAVE_GCRYPT
+        r = journal_file_hmac_put_object(f, OBJECT_DATA, o, p);
+        if (r < 0)
+                return r;
+#endif
+
+        /* The linking might have altered the window, so let's
+         * refresh our pointer */
+        r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
+        if (r < 0)
+                return r;
+
+        if (!data)
+                eq = NULL;
+        else
+                eq = memchr(data, '=', size);
+        if (eq && eq > data) {
+                Object *fo = NULL;
+                uint64_t fp;
+
+                /* Create field object ... */
+                r = journal_file_append_field(f, data, (uint8_t*) eq - (uint8_t*) data, &fo, &fp);
+                if (r < 0)
+                        return r;
+
+                /* ... and link it in. */
+                o->data.next_field_offset = fo->field.head_data_offset;
+                fo->field.head_data_offset = le64toh(p);
+        }
+
+        if (ret)
+                *ret = o;
+
+        if (offset)
+                *offset = p;
+
+        return 0;
+}
+
+uint64_t journal_file_entry_n_items(Object *o) {
+        assert(o);
+
+        if (o->object.type != OBJECT_ENTRY)
+                return 0;
+
+        return (le64toh(o->object.size) - offsetof(Object, entry.items)) / sizeof(EntryItem);
+}
+
+uint64_t journal_file_entry_array_n_items(Object *o) {
+        assert(o);
+
+        if (o->object.type != OBJECT_ENTRY_ARRAY)
+                return 0;
+
+        return (le64toh(o->object.size) - offsetof(Object, entry_array.items)) / sizeof(uint64_t);
+}
+
+uint64_t journal_file_hash_table_n_items(Object *o) {
+        assert(o);
+
+        if (!IN_SET(o->object.type, OBJECT_DATA_HASH_TABLE, OBJECT_FIELD_HASH_TABLE))
+                return 0;
+
+        return (le64toh(o->object.size) - offsetof(Object, hash_table.items)) / sizeof(HashItem);
+}
+
+static int link_entry_into_array(JournalFile *f,
+                                 le64_t *first,
+                                 le64_t *idx,
+                                 uint64_t p) {
+        int r;
+        uint64_t n = 0, ap = 0, q, i, a, hidx;
+        Object *o;
+
+        assert(f);
+        assert(f->header);
+        assert(first);
+        assert(idx);
+        assert(p > 0);
+
+        a = le64toh(*first);
+        i = hidx = le64toh(*idx);
+        while (a > 0) {
+
+                r = journal_file_move_to_object(f, OBJECT_ENTRY_ARRAY, a, &o);
+                if (r < 0)
+                        return r;
+
+                n = journal_file_entry_array_n_items(o);
+                if (i < n) {
+                        o->entry_array.items[i] = htole64(p);
+                        *idx = htole64(hidx + 1);
+                        return 0;
+                }
+
+                i -= n;
+                ap = a;
+                a = le64toh(o->entry_array.next_entry_array_offset);
+        }
+
+        if (hidx > n)
+                n = (hidx+1) * 2;
+        else
+                n = n * 2;
+
+        if (n < 4)
+                n = 4;
+
+        r = journal_file_append_object(f, OBJECT_ENTRY_ARRAY,
+                                       offsetof(Object, entry_array.items) + n * sizeof(uint64_t),
+                                       &o, &q);
+        if (r < 0)
+                return r;
+
+#if HAVE_GCRYPT
+        r = journal_file_hmac_put_object(f, OBJECT_ENTRY_ARRAY, o, q);
+        if (r < 0)
+                return r;
+#endif
+
+        o->entry_array.items[i] = htole64(p);
+
+        if (ap == 0)
+                *first = htole64(q);
+        else {
+                r = journal_file_move_to_object(f, OBJECT_ENTRY_ARRAY, ap, &o);
+                if (r < 0)
+                        return r;
+
+                o->entry_array.next_entry_array_offset = htole64(q);
+        }
+
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_entry_arrays))
+                f->header->n_entry_arrays = htole64(le64toh(f->header->n_entry_arrays) + 1);
+
+        *idx = htole64(hidx + 1);
+
+        return 0;
+}
+
+static int link_entry_into_array_plus_one(JournalFile *f,
+                                          le64_t *extra,
+                                          le64_t *first,
+                                          le64_t *idx,
+                                          uint64_t p) {
+
+        int r;
+
+        assert(f);
+        assert(extra);
+        assert(first);
+        assert(idx);
+        assert(p > 0);
+
+        if (*idx == 0)
+                *extra = htole64(p);
+        else {
+                le64_t i;
+
+                i = htole64(le64toh(*idx) - 1);
+                r = link_entry_into_array(f, first, &i, p);
+                if (r < 0)
+                        return r;
+        }
+
+        *idx = htole64(le64toh(*idx) + 1);
+        return 0;
+}
+
+static int journal_file_link_entry_item(JournalFile *f, Object *o, uint64_t offset, uint64_t i) {
+        uint64_t p;
+        int r;
+        assert(f);
+        assert(o);
+        assert(offset > 0);
+
+        p = le64toh(o->entry.items[i].object_offset);
+        if (p == 0)
+                return -EINVAL;
+
+        r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
+        if (r < 0)
+                return r;
+
+        return link_entry_into_array_plus_one(f,
+                                              &o->data.entry_offset,
+                                              &o->data.entry_array_offset,
+                                              &o->data.n_entries,
+                                              offset);
+}
+
+static int journal_file_link_entry(JournalFile *f, Object *o, uint64_t offset) {
+        uint64_t n, i;
+        int r;
+
+        assert(f);
+        assert(f->header);
+        assert(o);
+        assert(offset > 0);
+
+        if (o->object.type != OBJECT_ENTRY)
+                return -EINVAL;
+
+        __sync_synchronize();
+
+        /* Link up the entry itself */
+        r = link_entry_into_array(f,
+                                  &f->header->entry_array_offset,
+                                  &f->header->n_entries,
+                                  offset);
+        if (r < 0)
+                return r;
+
+        /* log_debug("=> %s seqnr=%"PRIu64" n_entries=%"PRIu64, f->path, o->entry.seqnum, f->header->n_entries); */
+
+        if (f->header->head_entry_realtime == 0)
+                f->header->head_entry_realtime = o->entry.realtime;
+
+        f->header->tail_entry_realtime = o->entry.realtime;
+        f->header->tail_entry_monotonic = o->entry.monotonic;
+
+        /* Link up the items */
+        n = journal_file_entry_n_items(o);
+        for (i = 0; i < n; i++) {
+                r = journal_file_link_entry_item(f, o, offset, i);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int journal_file_append_entry_internal(
+                JournalFile *f,
+                const dual_timestamp *ts,
+                const sd_id128_t *boot_id,
+                uint64_t xor_hash,
+                const EntryItem items[], unsigned n_items,
+                uint64_t *seqnum,
+                Object **ret, uint64_t *offset) {
+        uint64_t np;
+        uint64_t osize;
+        Object *o;
+        int r;
+
+        assert(f);
+        assert(f->header);
+        assert(items || n_items == 0);
+        assert(ts);
+
+        osize = offsetof(Object, entry.items) + (n_items * sizeof(EntryItem));
+
+        r = journal_file_append_object(f, OBJECT_ENTRY, osize, &o, &np);
+        if (r < 0)
+                return r;
+
+        o->entry.seqnum = htole64(journal_file_entry_seqnum(f, seqnum));
+        memcpy_safe(o->entry.items, items, n_items * sizeof(EntryItem));
+        o->entry.realtime = htole64(ts->realtime);
+        o->entry.monotonic = htole64(ts->monotonic);
+        o->entry.xor_hash = htole64(xor_hash);
+        o->entry.boot_id = boot_id ? *boot_id : f->header->boot_id;
+
+#if HAVE_GCRYPT
+        r = journal_file_hmac_put_object(f, OBJECT_ENTRY, o, np);
+        if (r < 0)
+                return r;
+#endif
+
+        r = journal_file_link_entry(f, o, np);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = o;
+
+        if (offset)
+                *offset = np;
+
+        return 0;
+}
+
+void journal_file_post_change(JournalFile *f) {
+        assert(f);
+
+        if (f->fd < 0)
+                return;
+
+        /* inotify() does not receive IN_MODIFY events from file
+         * accesses done via mmap(). After each access we hence
+         * trigger IN_MODIFY by truncating the journal file to its
+         * current size which triggers IN_MODIFY. */
+
+        __sync_synchronize();
+
+        if (ftruncate(f->fd, f->last_stat.st_size) < 0)
+                log_debug_errno(errno, "Failed to truncate file to its own size: %m");
+}
+
+static int post_change_thunk(sd_event_source *timer, uint64_t usec, void *userdata) {
+        assert(userdata);
+
+        journal_file_post_change(userdata);
+
+        return 1;
+}
+
+static void schedule_post_change(JournalFile *f) {
+        uint64_t now;
+        int r;
+
+        assert(f);
+        assert(f->post_change_timer);
+
+        r = sd_event_source_get_enabled(f->post_change_timer, NULL);
+        if (r < 0) {
+                log_debug_errno(r, "Failed to get ftruncate timer state: %m");
+                goto fail;
+        }
+        if (r > 0)
+                return;
+
+        r = sd_event_now(sd_event_source_get_event(f->post_change_timer), CLOCK_MONOTONIC, &now);
+        if (r < 0) {
+                log_debug_errno(r, "Failed to get clock's now for scheduling ftruncate: %m");
+                goto fail;
+        }
+
+        r = sd_event_source_set_time(f->post_change_timer, now + f->post_change_timer_period);
+        if (r < 0) {
+                log_debug_errno(r, "Failed to set time for scheduling ftruncate: %m");
+                goto fail;
+        }
+
+        r = sd_event_source_set_enabled(f->post_change_timer, SD_EVENT_ONESHOT);
+        if (r < 0) {
+                log_debug_errno(r, "Failed to enable scheduled ftruncate: %m");
+                goto fail;
+        }
+
+        return;
+
+fail:
+        /* On failure, let's simply post the change immediately. */
+        journal_file_post_change(f);
+}
+
+/* Enable coalesced change posting in a timer on the provided sd_event instance */
+int journal_file_enable_post_change_timer(JournalFile *f, sd_event *e, usec_t t) {
+        _cleanup_(sd_event_source_unrefp) sd_event_source *timer = NULL;
+        int r;
+
+        assert(f);
+        assert_return(!f->post_change_timer, -EINVAL);
+        assert(e);
+        assert(t);
+
+        r = sd_event_add_time(e, &timer, CLOCK_MONOTONIC, 0, 0, post_change_thunk, f);
+        if (r < 0)
+                return r;
+
+        r = sd_event_source_set_enabled(timer, SD_EVENT_OFF);
+        if (r < 0)
+                return r;
+
+        f->post_change_timer = TAKE_PTR(timer);
+        f->post_change_timer_period = t;
+
+        return r;
+}
+
+static int entry_item_cmp(const EntryItem *a, const EntryItem *b) {
+        return CMP(le64toh(a->object_offset), le64toh(b->object_offset));
+}
+
+int journal_file_append_entry(
+                JournalFile *f,
+                const dual_timestamp *ts,
+                const sd_id128_t *boot_id,
+                const struct iovec iovec[], unsigned n_iovec,
+                uint64_t *seqnum,
+                Object **ret, uint64_t *offset) {
+
+        unsigned i;
+        EntryItem *items;
+        int r;
+        uint64_t xor_hash = 0;
+        struct dual_timestamp _ts;
+
+        assert(f);
+        assert(f->header);
+        assert(iovec || n_iovec == 0);
+
+        if (ts) {
+                if (!VALID_REALTIME(ts->realtime))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid realtime timestamp %" PRIu64 ", refusing entry.",
+                                               ts->realtime);
+                if (!VALID_MONOTONIC(ts->monotonic))
+                        return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                               "Invalid monotomic timestamp %" PRIu64 ", refusing entry.",
+                                               ts->monotonic);
+        } else {
+                dual_timestamp_get(&_ts);
+                ts = &_ts;
+        }
+
+#if HAVE_GCRYPT
+        r = journal_file_maybe_append_tag(f, ts->realtime);
+        if (r < 0)
+                return r;
+#endif
+
+        /* alloca() can't take 0, hence let's allocate at least one */
+        items = newa(EntryItem, MAX(1u, n_iovec));
+
+        for (i = 0; i < n_iovec; i++) {
+                uint64_t p;
+                Object *o;
+
+                r = journal_file_append_data(f, iovec[i].iov_base, iovec[i].iov_len, &o, &p);
+                if (r < 0)
+                        return r;
+
+                xor_hash ^= le64toh(o->data.hash);
+                items[i].object_offset = htole64(p);
+                items[i].hash = o->data.hash;
+        }
+
+        /* Order by the position on disk, in order to improve seek
+         * times for rotating media. */
+        typesafe_qsort(items, n_iovec, entry_item_cmp);
+
+        r = journal_file_append_entry_internal(f, ts, boot_id, xor_hash, items, n_iovec, seqnum, ret, offset);
+
+        /* If the memory mapping triggered a SIGBUS then we return an
+         * IO error and ignore the error code passed down to us, since
+         * it is very likely just an effect of a nullified replacement
+         * mapping page */
+
+        if (mmap_cache_got_sigbus(f->mmap, f->cache_fd))
+                r = -EIO;
+
+        if (f->post_change_timer)
+                schedule_post_change(f);
+        else
+                journal_file_post_change(f);
+
+        return r;
+}
+
+typedef struct ChainCacheItem {
+        uint64_t first; /* the array at the beginning of the chain */
+        uint64_t array; /* the cached array */
+        uint64_t begin; /* the first item in the cached array */
+        uint64_t total; /* the total number of items in all arrays before this one in the chain */
+        uint64_t last_index; /* the last index we looked at, to optimize locality when bisecting */
+} ChainCacheItem;
+
+static void chain_cache_put(
+                OrderedHashmap *h,
+                ChainCacheItem *ci,
+                uint64_t first,
+                uint64_t array,
+                uint64_t begin,
+                uint64_t total,
+                uint64_t last_index) {
+
+        if (!ci) {
+                /* If the chain item to cache for this chain is the
+                 * first one it's not worth caching anything */
+                if (array == first)
+                        return;
+
+                if (ordered_hashmap_size(h) >= CHAIN_CACHE_MAX) {
+                        ci = ordered_hashmap_steal_first(h);
+                        assert(ci);
+                } else {
+                        ci = new(ChainCacheItem, 1);
+                        if (!ci)
+                                return;
+                }
+
+                ci->first = first;
+
+                if (ordered_hashmap_put(h, &ci->first, ci) < 0) {
+                        free(ci);
+                        return;
+                }
+        } else
+                assert(ci->first == first);
+
+        ci->array = array;
+        ci->begin = begin;
+        ci->total = total;
+        ci->last_index = last_index;
+}
+
+static int generic_array_get(
+                JournalFile *f,
+                uint64_t first,
+                uint64_t i,
+                Object **ret, uint64_t *offset) {
+
+        Object *o;
+        uint64_t p = 0, a, t = 0;
+        int r;
+        ChainCacheItem *ci;
+
+        assert(f);
+
+        a = first;
+
+        /* Try the chain cache first */
+        ci = ordered_hashmap_get(f->chain_cache, &first);
+        if (ci && i > ci->total) {
+                a = ci->array;
+                i -= ci->total;
+                t = ci->total;
+        }
+
+        while (a > 0) {
+                uint64_t k;
+
+                r = journal_file_move_to_object(f, OBJECT_ENTRY_ARRAY, a, &o);
+                if (r < 0)
+                        return r;
+
+                k = journal_file_entry_array_n_items(o);
+                if (i < k) {
+                        p = le64toh(o->entry_array.items[i]);
+                        goto found;
+                }
+
+                i -= k;
+                t += k;
+                a = le64toh(o->entry_array.next_entry_array_offset);
+        }
+
+        return 0;
+
+found:
+        /* Let's cache this item for the next invocation */
+        chain_cache_put(f->chain_cache, ci, first, a, le64toh(o->entry_array.items[0]), t, i);
+
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, p, &o);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = o;
+
+        if (offset)
+                *offset = p;
+
+        return 1;
+}
+
+static int generic_array_get_plus_one(
+                JournalFile *f,
+                uint64_t extra,
+                uint64_t first,
+                uint64_t i,
+                Object **ret, uint64_t *offset) {
+
+        Object *o;
+
+        assert(f);
+
+        if (i == 0) {
+                int r;
+
+                r = journal_file_move_to_object(f, OBJECT_ENTRY, extra, &o);
+                if (r < 0)
+                        return r;
+
+                if (ret)
+                        *ret = o;
+
+                if (offset)
+                        *offset = extra;
+
+                return 1;
+        }
+
+        return generic_array_get(f, first, i-1, ret, offset);
+}
+
+enum {
+        TEST_FOUND,
+        TEST_LEFT,
+        TEST_RIGHT
+};
+
+static int generic_array_bisect(
+                JournalFile *f,
+                uint64_t first,
+                uint64_t n,
+                uint64_t needle,
+                int (*test_object)(JournalFile *f, uint64_t p, uint64_t needle),
+                direction_t direction,
+                Object **ret,
+                uint64_t *offset,
+                uint64_t *idx) {
+
+        uint64_t a, p, t = 0, i = 0, last_p = 0, last_index = (uint64_t) -1;
+        bool subtract_one = false;
+        Object *o, *array = NULL;
+        int r;
+        ChainCacheItem *ci;
+
+        assert(f);
+        assert(test_object);
+
+        /* Start with the first array in the chain */
+        a = first;
+
+        ci = ordered_hashmap_get(f->chain_cache, &first);
+        if (ci && n > ci->total && ci->begin != 0) {
+                /* Ah, we have iterated this bisection array chain
+                 * previously! Let's see if we can skip ahead in the
+                 * chain, as far as the last time. But we can't jump
+                 * backwards in the chain, so let's check that
+                 * first. */
+
+                r = test_object(f, ci->begin, needle);
+                if (r < 0)
+                        return r;
+
+                if (r == TEST_LEFT) {
+                        /* OK, what we are looking for is right of the
+                         * begin of this EntryArray, so let's jump
+                         * straight to previously cached array in the
+                         * chain */
+
+                        a = ci->array;
+                        n -= ci->total;
+                        t = ci->total;
+                        last_index = ci->last_index;
+                }
+        }
+
+        while (a > 0) {
+                uint64_t left, right, k, lp;
+
+                r = journal_file_move_to_object(f, OBJECT_ENTRY_ARRAY, a, &array);
+                if (r < 0)
+                        return r;
+
+                k = journal_file_entry_array_n_items(array);
+                right = MIN(k, n);
+                if (right <= 0)
+                        return 0;
+
+                i = right - 1;
+                lp = p = le64toh(array->entry_array.items[i]);
+                if (p <= 0)
+                        r = -EBADMSG;
+                else
+                        r = test_object(f, p, needle);
+                if (r == -EBADMSG) {
+                        log_debug_errno(r, "Encountered invalid entry while bisecting, cutting algorithm short. (1)");
+                        n = i;
+                        continue;
+                }
+                if (r < 0)
+                        return r;
+
+                if (r == TEST_FOUND)
+                        r = direction == DIRECTION_DOWN ? TEST_RIGHT : TEST_LEFT;
+
+                if (r == TEST_RIGHT) {
+                        left = 0;
+                        right -= 1;
+
+                        if (last_index != (uint64_t) -1) {
+                                assert(last_index <= right);
+
+                                /* If we cached the last index we
+                                 * looked at, let's try to not to jump
+                                 * too wildly around and see if we can
+                                 * limit the range to look at early to
+                                 * the immediate neighbors of the last
+                                 * index we looked at. */
+
+                                if (last_index > 0) {
+                                        uint64_t x = last_index - 1;
+
+                                        p = le64toh(array->entry_array.items[x]);
+                                        if (p <= 0)
+                                                return -EBADMSG;
+
+                                        r = test_object(f, p, needle);
+                                        if (r < 0)
+                                                return r;
+
+                                        if (r == TEST_FOUND)
+                                                r = direction == DIRECTION_DOWN ? TEST_RIGHT : TEST_LEFT;
+
+                                        if (r == TEST_RIGHT)
+                                                right = x;
+                                        else
+                                                left = x + 1;
+                                }
+
+                                if (last_index < right) {
+                                        uint64_t y = last_index + 1;
+
+                                        p = le64toh(array->entry_array.items[y]);
+                                        if (p <= 0)
+                                                return -EBADMSG;
+
+                                        r = test_object(f, p, needle);
+                                        if (r < 0)
+                                                return r;
+
+                                        if (r == TEST_FOUND)
+                                                r = direction == DIRECTION_DOWN ? TEST_RIGHT : TEST_LEFT;
+
+                                        if (r == TEST_RIGHT)
+                                                right = y;
+                                        else
+                                                left = y + 1;
+                                }
+                        }
+
+                        for (;;) {
+                                if (left == right) {
+                                        if (direction == DIRECTION_UP)
+                                                subtract_one = true;
+
+                                        i = left;
+                                        goto found;
+                                }
+
+                                assert(left < right);
+                                i = (left + right) / 2;
+
+                                p = le64toh(array->entry_array.items[i]);
+                                if (p <= 0)
+                                        r = -EBADMSG;
+                                else
+                                        r = test_object(f, p, needle);
+                                if (r == -EBADMSG) {
+                                        log_debug_errno(r, "Encountered invalid entry while bisecting, cutting algorithm short. (2)");
+                                        right = n = i;
+                                        continue;
+                                }
+                                if (r < 0)
+                                        return r;
+
+                                if (r == TEST_FOUND)
+                                        r = direction == DIRECTION_DOWN ? TEST_RIGHT : TEST_LEFT;
+
+                                if (r == TEST_RIGHT)
+                                        right = i;
+                                else
+                                        left = i + 1;
+                        }
+                }
+
+                if (k >= n) {
+                        if (direction == DIRECTION_UP) {
+                                i = n;
+                                subtract_one = true;
+                                goto found;
+                        }
+
+                        return 0;
+                }
+
+                last_p = lp;
+
+                n -= k;
+                t += k;
+                last_index = (uint64_t) -1;
+                a = le64toh(array->entry_array.next_entry_array_offset);
+        }
+
+        return 0;
+
+found:
+        if (subtract_one && t == 0 && i == 0)
+                return 0;
+
+        /* Let's cache this item for the next invocation */
+        chain_cache_put(f->chain_cache, ci, first, a, le64toh(array->entry_array.items[0]), t, subtract_one ? (i > 0 ? i-1 : (uint64_t) -1) : i);
+
+        if (subtract_one && i == 0)
+                p = last_p;
+        else if (subtract_one)
+                p = le64toh(array->entry_array.items[i-1]);
+        else
+                p = le64toh(array->entry_array.items[i]);
+
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, p, &o);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = o;
+
+        if (offset)
+                *offset = p;
+
+        if (idx)
+                *idx = t + i + (subtract_one ? -1 : 0);
+
+        return 1;
+}
+
+static int generic_array_bisect_plus_one(
+                JournalFile *f,
+                uint64_t extra,
+                uint64_t first,
+                uint64_t n,
+                uint64_t needle,
+                int (*test_object)(JournalFile *f, uint64_t p, uint64_t needle),
+                direction_t direction,
+                Object **ret,
+                uint64_t *offset,
+                uint64_t *idx) {
+
+        int r;
+        bool step_back = false;
+        Object *o;
+
+        assert(f);
+        assert(test_object);
+
+        if (n <= 0)
+                return 0;
+
+        /* This bisects the array in object 'first', but first checks
+         * an extra  */
+        r = test_object(f, extra, needle);
+        if (r < 0)
+                return r;
+
+        if (r == TEST_FOUND)
+                r = direction == DIRECTION_DOWN ? TEST_RIGHT : TEST_LEFT;
+
+        /* if we are looking with DIRECTION_UP then we need to first
+           see if in the actual array there is a matching entry, and
+           return the last one of that. But if there isn't any we need
+           to return this one. Hence remember this, and return it
+           below. */
+        if (r == TEST_LEFT)
+                step_back = direction == DIRECTION_UP;
+
+        if (r == TEST_RIGHT) {
+                if (direction == DIRECTION_DOWN)
+                        goto found;
+                else
+                        return 0;
+        }
+
+        r = generic_array_bisect(f, first, n-1, needle, test_object, direction, ret, offset, idx);
+
+        if (r == 0 && step_back)
+                goto found;
+
+        if (r > 0 && idx)
+                (*idx)++;
+
+        return r;
+
+found:
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, extra, &o);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = o;
+
+        if (offset)
+                *offset = extra;
+
+        if (idx)
+                *idx = 0;
+
+        return 1;
+}
+
+_pure_ static int test_object_offset(JournalFile *f, uint64_t p, uint64_t needle) {
+        assert(f);
+        assert(p > 0);
+
+        if (p == needle)
+                return TEST_FOUND;
+        else if (p < needle)
+                return TEST_LEFT;
+        else
+                return TEST_RIGHT;
+}
+
+static int test_object_seqnum(JournalFile *f, uint64_t p, uint64_t needle) {
+        Object *o;
+        int r;
+
+        assert(f);
+        assert(p > 0);
+
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, p, &o);
+        if (r < 0)
+                return r;
+
+        if (le64toh(o->entry.seqnum) == needle)
+                return TEST_FOUND;
+        else if (le64toh(o->entry.seqnum) < needle)
+                return TEST_LEFT;
+        else
+                return TEST_RIGHT;
+}
+
+int journal_file_move_to_entry_by_seqnum(
+                JournalFile *f,
+                uint64_t seqnum,
+                direction_t direction,
+                Object **ret,
+                uint64_t *offset) {
+        assert(f);
+        assert(f->header);
+
+        return generic_array_bisect(f,
+                                    le64toh(f->header->entry_array_offset),
+                                    le64toh(f->header->n_entries),
+                                    seqnum,
+                                    test_object_seqnum,
+                                    direction,
+                                    ret, offset, NULL);
+}
+
+static int test_object_realtime(JournalFile *f, uint64_t p, uint64_t needle) {
+        Object *o;
+        int r;
+
+        assert(f);
+        assert(p > 0);
+
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, p, &o);
+        if (r < 0)
+                return r;
+
+        if (le64toh(o->entry.realtime) == needle)
+                return TEST_FOUND;
+        else if (le64toh(o->entry.realtime) < needle)
+                return TEST_LEFT;
+        else
+                return TEST_RIGHT;
+}
+
+int journal_file_move_to_entry_by_realtime(
+                JournalFile *f,
+                uint64_t realtime,
+                direction_t direction,
+                Object **ret,
+                uint64_t *offset) {
+        assert(f);
+        assert(f->header);
+
+        return generic_array_bisect(f,
+                                    le64toh(f->header->entry_array_offset),
+                                    le64toh(f->header->n_entries),
+                                    realtime,
+                                    test_object_realtime,
+                                    direction,
+                                    ret, offset, NULL);
+}
+
+static int test_object_monotonic(JournalFile *f, uint64_t p, uint64_t needle) {
+        Object *o;
+        int r;
+
+        assert(f);
+        assert(p > 0);
+
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, p, &o);
+        if (r < 0)
+                return r;
+
+        if (le64toh(o->entry.monotonic) == needle)
+                return TEST_FOUND;
+        else if (le64toh(o->entry.monotonic) < needle)
+                return TEST_LEFT;
+        else
+                return TEST_RIGHT;
+}
+
+static int find_data_object_by_boot_id(
+                JournalFile *f,
+                sd_id128_t boot_id,
+                Object **o,
+                uint64_t *b) {
+
+        char t[STRLEN("_BOOT_ID=") + 32 + 1] = "_BOOT_ID=";
+
+        sd_id128_to_string(boot_id, t + 9);
+        return journal_file_find_data_object(f, t, sizeof(t) - 1, o, b);
+}
+
+int journal_file_move_to_entry_by_monotonic(
+                JournalFile *f,
+                sd_id128_t boot_id,
+                uint64_t monotonic,
+                direction_t direction,
+                Object **ret,
+                uint64_t *offset) {
+
+        Object *o;
+        int r;
+
+        assert(f);
+
+        r = find_data_object_by_boot_id(f, boot_id, &o, NULL);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ENOENT;
+
+        return generic_array_bisect_plus_one(f,
+                                             le64toh(o->data.entry_offset),
+                                             le64toh(o->data.entry_array_offset),
+                                             le64toh(o->data.n_entries),
+                                             monotonic,
+                                             test_object_monotonic,
+                                             direction,
+                                             ret, offset, NULL);
+}
+
+void journal_file_reset_location(JournalFile *f) {
+        f->location_type = LOCATION_HEAD;
+        f->current_offset = 0;
+        f->current_seqnum = 0;
+        f->current_realtime = 0;
+        f->current_monotonic = 0;
+        zero(f->current_boot_id);
+        f->current_xor_hash = 0;
+}
+
+void journal_file_save_location(JournalFile *f, Object *o, uint64_t offset) {
+        f->location_type = LOCATION_SEEK;
+        f->current_offset = offset;
+        f->current_seqnum = le64toh(o->entry.seqnum);
+        f->current_realtime = le64toh(o->entry.realtime);
+        f->current_monotonic = le64toh(o->entry.monotonic);
+        f->current_boot_id = o->entry.boot_id;
+        f->current_xor_hash = le64toh(o->entry.xor_hash);
+}
+
+int journal_file_compare_locations(JournalFile *af, JournalFile *bf) {
+        int r;
+
+        assert(af);
+        assert(af->header);
+        assert(bf);
+        assert(bf->header);
+        assert(af->location_type == LOCATION_SEEK);
+        assert(bf->location_type == LOCATION_SEEK);
+
+        /* If contents and timestamps match, these entries are
+         * identical, even if the seqnum does not match */
+        if (sd_id128_equal(af->current_boot_id, bf->current_boot_id) &&
+            af->current_monotonic == bf->current_monotonic &&
+            af->current_realtime == bf->current_realtime &&
+            af->current_xor_hash == bf->current_xor_hash)
+                return 0;
+
+        if (sd_id128_equal(af->header->seqnum_id, bf->header->seqnum_id)) {
+
+                /* If this is from the same seqnum source, compare
+                 * seqnums */
+                r = CMP(af->current_seqnum, bf->current_seqnum);
+                if (r != 0)
+                        return r;
+
+                /* Wow! This is weird, different data but the same
+                 * seqnums? Something is borked, but let's make the
+                 * best of it and compare by time. */
+        }
+
+        if (sd_id128_equal(af->current_boot_id, bf->current_boot_id)) {
+
+                /* If the boot id matches, compare monotonic time */
+                r = CMP(af->current_monotonic, bf->current_monotonic);
+                if (r != 0)
+                        return r;
+        }
+
+        /* Otherwise, compare UTC time */
+        r = CMP(af->current_realtime, bf->current_realtime);
+        if (r != 0)
+                return r;
+
+        /* Finally, compare by contents */
+        return CMP(af->current_xor_hash, bf->current_xor_hash);
+}
+
+static int bump_array_index(uint64_t *i, direction_t direction, uint64_t n) {
+
+        /* Increase or decrease the specified index, in the right direction. */
+
+        if (direction == DIRECTION_DOWN) {
+                if (*i >= n - 1)
+                        return 0;
+
+                (*i) ++;
+        } else {
+                if (*i <= 0)
+                        return 0;
+
+                (*i) --;
+        }
+
+        return 1;
+}
+
+static bool check_properly_ordered(uint64_t new_offset, uint64_t old_offset, direction_t direction) {
+
+        /* Consider it an error if any of the two offsets is uninitialized */
+        if (old_offset == 0 || new_offset == 0)
+                return false;
+
+        /* If we go down, the new offset must be larger than the old one. */
+        return direction == DIRECTION_DOWN ?
+                new_offset > old_offset  :
+                new_offset < old_offset;
+}
+
+int journal_file_next_entry(
+                JournalFile *f,
+                uint64_t p,
+                direction_t direction,
+                Object **ret, uint64_t *offset) {
+
+        uint64_t i, n, ofs;
+        int r;
+
+        assert(f);
+        assert(f->header);
+
+        n = le64toh(f->header->n_entries);
+        if (n <= 0)
+                return 0;
+
+        if (p == 0)
+                i = direction == DIRECTION_DOWN ? 0 : n - 1;
+        else {
+                r = generic_array_bisect(f,
+                                         le64toh(f->header->entry_array_offset),
+                                         le64toh(f->header->n_entries),
+                                         p,
+                                         test_object_offset,
+                                         DIRECTION_DOWN,
+                                         NULL, NULL,
+                                         &i);
+                if (r <= 0)
+                        return r;
+
+                r = bump_array_index(&i, direction, n);
+                if (r <= 0)
+                        return r;
+        }
+
+        /* And jump to it */
+        for (;;) {
+                r = generic_array_get(f,
+                                      le64toh(f->header->entry_array_offset),
+                                      i,
+                                      ret, &ofs);
+                if (r > 0)
+                        break;
+                if (r != -EBADMSG)
+                        return r;
+
+                /* OK, so this entry is borked. Most likely some entry didn't get synced to disk properly, let's see if
+                 * the next one might work for us instead. */
+                log_debug_errno(r, "Entry item %" PRIu64 " is bad, skipping over it.", i);
+
+                r = bump_array_index(&i, direction, n);
+                if (r <= 0)
+                        return r;
+        }
+
+        /* Ensure our array is properly ordered. */
+        if (p > 0 && !check_properly_ordered(ofs, p, direction))
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "%s: entry array not properly ordered at entry %" PRIu64,
+                                       f->path, i);
+
+        if (offset)
+                *offset = ofs;
+
+        return 1;
+}
+
+int journal_file_next_entry_for_data(
+                JournalFile *f,
+                Object *o, uint64_t p,
+                uint64_t data_offset,
+                direction_t direction,
+                Object **ret, uint64_t *offset) {
+
+        uint64_t i, n, ofs;
+        Object *d;
+        int r;
+
+        assert(f);
+        assert(p > 0 || !o);
+
+        r = journal_file_move_to_object(f, OBJECT_DATA, data_offset, &d);
+        if (r < 0)
+                return r;
+
+        n = le64toh(d->data.n_entries);
+        if (n <= 0)
+                return n;
+
+        if (!o)
+                i = direction == DIRECTION_DOWN ? 0 : n - 1;
+        else {
+                if (o->object.type != OBJECT_ENTRY)
+                        return -EINVAL;
+
+                r = generic_array_bisect_plus_one(f,
+                                                  le64toh(d->data.entry_offset),
+                                                  le64toh(d->data.entry_array_offset),
+                                                  le64toh(d->data.n_entries),
+                                                  p,
+                                                  test_object_offset,
+                                                  DIRECTION_DOWN,
+                                                  NULL, NULL,
+                                                  &i);
+
+                if (r <= 0)
+                        return r;
+
+                r = bump_array_index(&i, direction, n);
+                if (r <= 0)
+                        return r;
+        }
+
+        for (;;) {
+                r = generic_array_get_plus_one(f,
+                                               le64toh(d->data.entry_offset),
+                                               le64toh(d->data.entry_array_offset),
+                                               i,
+                                               ret, &ofs);
+                if (r > 0)
+                        break;
+                if (r != -EBADMSG)
+                        return r;
+
+                log_debug_errno(r, "Data entry item %" PRIu64 " is bad, skipping over it.", i);
+
+                r = bump_array_index(&i, direction, n);
+                if (r <= 0)
+                        return r;
+        }
+
+        /* Ensure our array is properly ordered. */
+        if (p > 0 && check_properly_ordered(ofs, p, direction))
+                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "%s data entry array not properly ordered at entry %" PRIu64,
+                                       f->path, i);
+
+        if (offset)
+                *offset = ofs;
+
+        return 1;
+}
+
+int journal_file_move_to_entry_by_offset_for_data(
+                JournalFile *f,
+                uint64_t data_offset,
+                uint64_t p,
+                direction_t direction,
+                Object **ret, uint64_t *offset) {
+
+        int r;
+        Object *d;
+
+        assert(f);
+
+        r = journal_file_move_to_object(f, OBJECT_DATA, data_offset, &d);
+        if (r < 0)
+                return r;
+
+        return generic_array_bisect_plus_one(f,
+                                             le64toh(d->data.entry_offset),
+                                             le64toh(d->data.entry_array_offset),
+                                             le64toh(d->data.n_entries),
+                                             p,
+                                             test_object_offset,
+                                             direction,
+                                             ret, offset, NULL);
+}
+
+int journal_file_move_to_entry_by_monotonic_for_data(
+                JournalFile *f,
+                uint64_t data_offset,
+                sd_id128_t boot_id,
+                uint64_t monotonic,
+                direction_t direction,
+                Object **ret, uint64_t *offset) {
+
+        Object *o, *d;
+        int r;
+        uint64_t b, z;
+
+        assert(f);
+
+        /* First, seek by time */
+        r = find_data_object_by_boot_id(f, boot_id, &o, &b);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -ENOENT;
+
+        r = generic_array_bisect_plus_one(f,
+                                          le64toh(o->data.entry_offset),
+                                          le64toh(o->data.entry_array_offset),
+                                          le64toh(o->data.n_entries),
+                                          monotonic,
+                                          test_object_monotonic,
+                                          direction,
+                                          NULL, &z, NULL);
+        if (r <= 0)
+                return r;
+
+        /* And now, continue seeking until we find an entry that
+         * exists in both bisection arrays */
+
+        for (;;) {
+                Object *qo;
+                uint64_t p, q;
+
+                r = journal_file_move_to_object(f, OBJECT_DATA, data_offset, &d);
+                if (r < 0)
+                        return r;
+
+                r = generic_array_bisect_plus_one(f,
+                                                  le64toh(d->data.entry_offset),
+                                                  le64toh(d->data.entry_array_offset),
+                                                  le64toh(d->data.n_entries),
+                                                  z,
+                                                  test_object_offset,
+                                                  direction,
+                                                  NULL, &p, NULL);
+                if (r <= 0)
+                        return r;
+
+                r = journal_file_move_to_object(f, OBJECT_DATA, b, &o);
+                if (r < 0)
+                        return r;
+
+                r = generic_array_bisect_plus_one(f,
+                                                  le64toh(o->data.entry_offset),
+                                                  le64toh(o->data.entry_array_offset),
+                                                  le64toh(o->data.n_entries),
+                                                  p,
+                                                  test_object_offset,
+                                                  direction,
+                                                  &qo, &q, NULL);
+
+                if (r <= 0)
+                        return r;
+
+                if (p == q) {
+                        if (ret)
+                                *ret = qo;
+                        if (offset)
+                                *offset = q;
+
+                        return 1;
+                }
+
+                z = q;
+        }
+}
+
+int journal_file_move_to_entry_by_seqnum_for_data(
+                JournalFile *f,
+                uint64_t data_offset,
+                uint64_t seqnum,
+                direction_t direction,
+                Object **ret, uint64_t *offset) {
+
+        Object *d;
+        int r;
+
+        assert(f);
+
+        r = journal_file_move_to_object(f, OBJECT_DATA, data_offset, &d);
+        if (r < 0)
+                return r;
+
+        return generic_array_bisect_plus_one(f,
+                                             le64toh(d->data.entry_offset),
+                                             le64toh(d->data.entry_array_offset),
+                                             le64toh(d->data.n_entries),
+                                             seqnum,
+                                             test_object_seqnum,
+                                             direction,
+                                             ret, offset, NULL);
+}
+
+int journal_file_move_to_entry_by_realtime_for_data(
+                JournalFile *f,
+                uint64_t data_offset,
+                uint64_t realtime,
+                direction_t direction,
+                Object **ret, uint64_t *offset) {
+
+        Object *d;
+        int r;
+
+        assert(f);
+
+        r = journal_file_move_to_object(f, OBJECT_DATA, data_offset, &d);
+        if (r < 0)
+                return r;
+
+        return generic_array_bisect_plus_one(f,
+                                             le64toh(d->data.entry_offset),
+                                             le64toh(d->data.entry_array_offset),
+                                             le64toh(d->data.n_entries),
+                                             realtime,
+                                             test_object_realtime,
+                                             direction,
+                                             ret, offset, NULL);
+}
+
+void journal_file_dump(JournalFile *f) {
+        Object *o;
+        int r;
+        uint64_t p;
+
+        assert(f);
+        assert(f->header);
+
+        journal_file_print_header(f);
+
+        p = le64toh(f->header->header_size);
+        while (p != 0) {
+                r = journal_file_move_to_object(f, OBJECT_UNUSED, p, &o);
+                if (r < 0)
+                        goto fail;
+
+                switch (o->object.type) {
+
+                case OBJECT_UNUSED:
+                        printf("Type: OBJECT_UNUSED\n");
+                        break;
+
+                case OBJECT_DATA:
+                        printf("Type: OBJECT_DATA\n");
+                        break;
+
+                case OBJECT_FIELD:
+                        printf("Type: OBJECT_FIELD\n");
+                        break;
+
+                case OBJECT_ENTRY:
+                        printf("Type: OBJECT_ENTRY seqnum=%"PRIu64" monotonic=%"PRIu64" realtime=%"PRIu64"\n",
+                               le64toh(o->entry.seqnum),
+                               le64toh(o->entry.monotonic),
+                               le64toh(o->entry.realtime));
+                        break;
+
+                case OBJECT_FIELD_HASH_TABLE:
+                        printf("Type: OBJECT_FIELD_HASH_TABLE\n");
+                        break;
+
+                case OBJECT_DATA_HASH_TABLE:
+                        printf("Type: OBJECT_DATA_HASH_TABLE\n");
+                        break;
+
+                case OBJECT_ENTRY_ARRAY:
+                        printf("Type: OBJECT_ENTRY_ARRAY\n");
+                        break;
+
+                case OBJECT_TAG:
+                        printf("Type: OBJECT_TAG seqnum=%"PRIu64" epoch=%"PRIu64"\n",
+                               le64toh(o->tag.seqnum),
+                               le64toh(o->tag.epoch));
+                        break;
+
+                default:
+                        printf("Type: unknown (%i)\n", o->object.type);
+                        break;
+                }
+
+                if (o->object.flags & OBJECT_COMPRESSION_MASK)
+                        printf("Flags: %s\n",
+                               object_compressed_to_string(o->object.flags & OBJECT_COMPRESSION_MASK));
+
+                if (p == le64toh(f->header->tail_object_offset))
+                        p = 0;
+                else
+                        p = p + ALIGN64(le64toh(o->object.size));
+        }
+
+        return;
+fail:
+        log_error("File corrupt");
+}
+
+static const char* format_timestamp_safe(char *buf, size_t l, usec_t t) {
+        const char *x;
+
+        x = format_timestamp(buf, l, t);
+        if (x)
+                return x;
+        return " --- ";
+}
+
+void journal_file_print_header(JournalFile *f) {
+        char a[33], b[33], c[33], d[33];
+        char x[FORMAT_TIMESTAMP_MAX], y[FORMAT_TIMESTAMP_MAX], z[FORMAT_TIMESTAMP_MAX];
+        struct stat st;
+        char bytes[FORMAT_BYTES_MAX];
+
+        assert(f);
+        assert(f->header);
+
+        printf("File Path: %s\n"
+               "File ID: %s\n"
+               "Machine ID: %s\n"
+               "Boot ID: %s\n"
+               "Sequential Number ID: %s\n"
+               "State: %s\n"
+               "Compatible Flags:%s%s\n"
+               "Incompatible Flags:%s%s%s\n"
+               "Header size: %"PRIu64"\n"
+               "Arena size: %"PRIu64"\n"
+               "Data Hash Table Size: %"PRIu64"\n"
+               "Field Hash Table Size: %"PRIu64"\n"
+               "Rotate Suggested: %s\n"
+               "Head Sequential Number: %"PRIu64" (%"PRIx64")\n"
+               "Tail Sequential Number: %"PRIu64" (%"PRIx64")\n"
+               "Head Realtime Timestamp: %s (%"PRIx64")\n"
+               "Tail Realtime Timestamp: %s (%"PRIx64")\n"
+               "Tail Monotonic Timestamp: %s (%"PRIx64")\n"
+               "Objects: %"PRIu64"\n"
+               "Entry Objects: %"PRIu64"\n",
+               f->path,
+               sd_id128_to_string(f->header->file_id, a),
+               sd_id128_to_string(f->header->machine_id, b),
+               sd_id128_to_string(f->header->boot_id, c),
+               sd_id128_to_string(f->header->seqnum_id, d),
+               f->header->state == STATE_OFFLINE ? "OFFLINE" :
+               f->header->state == STATE_ONLINE ? "ONLINE" :
+               f->header->state == STATE_ARCHIVED ? "ARCHIVED" : "UNKNOWN",
+               JOURNAL_HEADER_SEALED(f->header) ? " SEALED" : "",
+               (le32toh(f->header->compatible_flags) & ~HEADER_COMPATIBLE_ANY) ? " ???" : "",
+               JOURNAL_HEADER_COMPRESSED_XZ(f->header) ? " COMPRESSED-XZ" : "",
+               JOURNAL_HEADER_COMPRESSED_LZ4(f->header) ? " COMPRESSED-LZ4" : "",
+               (le32toh(f->header->incompatible_flags) & ~HEADER_INCOMPATIBLE_ANY) ? " ???" : "",
+               le64toh(f->header->header_size),
+               le64toh(f->header->arena_size),
+               le64toh(f->header->data_hash_table_size) / sizeof(HashItem),
+               le64toh(f->header->field_hash_table_size) / sizeof(HashItem),
+               yes_no(journal_file_rotate_suggested(f, 0)),
+               le64toh(f->header->head_entry_seqnum), le64toh(f->header->head_entry_seqnum),
+               le64toh(f->header->tail_entry_seqnum), le64toh(f->header->tail_entry_seqnum),
+               format_timestamp_safe(x, sizeof(x), le64toh(f->header->head_entry_realtime)), le64toh(f->header->head_entry_realtime),
+               format_timestamp_safe(y, sizeof(y), le64toh(f->header->tail_entry_realtime)), le64toh(f->header->tail_entry_realtime),
+               format_timespan(z, sizeof(z), le64toh(f->header->tail_entry_monotonic), USEC_PER_MSEC), le64toh(f->header->tail_entry_monotonic),
+               le64toh(f->header->n_objects),
+               le64toh(f->header->n_entries));
+
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_data))
+                printf("Data Objects: %"PRIu64"\n"
+                       "Data Hash Table Fill: %.1f%%\n",
+                       le64toh(f->header->n_data),
+                       100.0 * (double) le64toh(f->header->n_data) / ((double) (le64toh(f->header->data_hash_table_size) / sizeof(HashItem))));
+
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_fields))
+                printf("Field Objects: %"PRIu64"\n"
+                       "Field Hash Table Fill: %.1f%%\n",
+                       le64toh(f->header->n_fields),
+                       100.0 * (double) le64toh(f->header->n_fields) / ((double) (le64toh(f->header->field_hash_table_size) / sizeof(HashItem))));
+
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_tags))
+                printf("Tag Objects: %"PRIu64"\n",
+                       le64toh(f->header->n_tags));
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_entry_arrays))
+                printf("Entry Array Objects: %"PRIu64"\n",
+                       le64toh(f->header->n_entry_arrays));
+
+        if (fstat(f->fd, &st) >= 0)
+                printf("Disk usage: %s\n", format_bytes(bytes, sizeof(bytes), (uint64_t) st.st_blocks * 512ULL));
+}
+
+static int journal_file_warn_btrfs(JournalFile *f) {
+        unsigned attrs;
+        int r;
+
+        assert(f);
+
+        /* Before we write anything, check if the COW logic is turned
+         * off on btrfs. Given our write pattern that is quite
+         * unfriendly to COW file systems this should greatly improve
+         * performance on COW file systems, such as btrfs, at the
+         * expense of data integrity features (which shouldn't be too
+         * bad, given that we do our own checksumming). */
+
+        r = btrfs_is_filesystem(f->fd);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to determine if journal is on btrfs: %m");
+        if (!r)
+                return 0;
+
+        r = read_attr_fd(f->fd, &attrs);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to read file attributes: %m");
+
+        if (attrs & FS_NOCOW_FL) {
+                log_debug("Detected btrfs file system with copy-on-write disabled, all is good.");
+                return 0;
+        }
+
+        log_notice("Creating journal file %s on a btrfs file system, and copy-on-write is enabled. "
+                   "This is likely to slow down journal access substantially, please consider turning "
+                   "off the copy-on-write file attribute on the journal directory, using chattr +C.", f->path);
+
+        return 1;
+}
+
+int journal_file_open(
+                int fd,
+                const char *fname,
+                int flags,
+                mode_t mode,
+                bool compress,
+                uint64_t compress_threshold_bytes,
+                bool seal,
+                JournalMetrics *metrics,
+                MMapCache *mmap_cache,
+                Set *deferred_closes,
+                JournalFile *template,
+                JournalFile **ret) {
+
+        bool newly_created = false;
+        JournalFile *f;
+        void *h;
+        int r;
+        char bytes[FORMAT_BYTES_MAX];
+
+        assert(ret);
+        assert(fd >= 0 || fname);
+
+        if (!IN_SET((flags & O_ACCMODE), O_RDONLY, O_RDWR))
+                return -EINVAL;
+
+        if (fname && (flags & O_CREAT) && !endswith(fname, ".journal"))
+                return -EINVAL;
+
+        f = new(JournalFile, 1);
+        if (!f)
+                return -ENOMEM;
+
+        *f = (JournalFile) {
+                .fd = fd,
+                .mode = mode,
+
+                .flags = flags,
+                .prot = prot_from_flags(flags),
+                .writable = (flags & O_ACCMODE) != O_RDONLY,
+
+#if HAVE_LZ4
+                .compress_lz4 = compress,
+#elif HAVE_XZ
+                .compress_xz = compress,
+#endif
+                .compress_threshold_bytes = compress_threshold_bytes == (uint64_t) -1 ?
+                                            DEFAULT_COMPRESS_THRESHOLD :
+                                            MAX(MIN_COMPRESS_THRESHOLD, compress_threshold_bytes),
+#if HAVE_GCRYPT
+                .seal = seal,
+#endif
+        };
+
+        log_debug("Journal effective settings seal=%s compress=%s compress_threshold_bytes=%s",
+                  yes_no(f->seal), yes_no(JOURNAL_FILE_COMPRESS(f)),
+                  format_bytes(bytes, sizeof(bytes), f->compress_threshold_bytes));
+
+        if (mmap_cache)
+                f->mmap = mmap_cache_ref(mmap_cache);
+        else {
+                f->mmap = mmap_cache_new();
+                if (!f->mmap) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        }
+
+        if (fname) {
+                f->path = strdup(fname);
+                if (!f->path) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        } else {
+                assert(fd >= 0);
+
+                /* If we don't know the path, fill in something explanatory and vaguely useful */
+                if (asprintf(&f->path, "/proc/self/%i", fd) < 0) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        }
+
+        f->chain_cache = ordered_hashmap_new(&uint64_hash_ops);
+        if (!f->chain_cache) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        if (f->fd < 0) {
+                /* We pass O_NONBLOCK here, so that in case somebody pointed us to some character device node or FIFO
+                 * or so, we likely fail quickly than block for long. For regular files O_NONBLOCK has no effect, hence
+                 * it doesn't hurt in that case. */
+
+                f->fd = open(f->path, f->flags|O_CLOEXEC|O_NONBLOCK, f->mode);
+                if (f->fd < 0) {
+                        r = -errno;
+                        goto fail;
+                }
+
+                /* fds we opened here by us should also be closed by us. */
+                f->close_fd = true;
+
+                r = fd_nonblock(f->fd, false);
+                if (r < 0)
+                        goto fail;
+        }
+
+        f->cache_fd = mmap_cache_add_fd(f->mmap, f->fd);
+        if (!f->cache_fd) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        r = journal_file_fstat(f);
+        if (r < 0)
+                goto fail;
+
+        if (f->last_stat.st_size == 0 && f->writable) {
+
+                (void) journal_file_warn_btrfs(f);
+
+                /* Let's attach the creation time to the journal file, so that the vacuuming code knows the age of this
+                 * file even if the file might end up corrupted one day... Ideally we'd just use the creation time many
+                 * file systems maintain for each file, but the API to query this is very new, hence let's emulate this
+                 * via extended attributes. If extended attributes are not supported we'll just skip this, and rely
+                 * solely on mtime/atime/ctime of the file. */
+                (void) fd_setcrtime(f->fd, 0);
+
+#if HAVE_GCRYPT
+                /* Try to load the FSPRG state, and if we can't, then
+                 * just don't do sealing */
+                if (f->seal) {
+                        r = journal_file_fss_load(f);
+                        if (r < 0)
+                                f->seal = false;
+                }
+#endif
+
+                r = journal_file_init_header(f, template);
+                if (r < 0)
+                        goto fail;
+
+                r = journal_file_fstat(f);
+                if (r < 0)
+                        goto fail;
+
+                newly_created = true;
+        }
+
+        if (f->last_stat.st_size < (off_t) HEADER_SIZE_MIN) {
+                r = -ENODATA;
+                goto fail;
+        }
+
+        r = mmap_cache_get(f->mmap, f->cache_fd, f->prot, CONTEXT_HEADER, true, 0, PAGE_ALIGN(sizeof(Header)), &f->last_stat, &h, NULL);
+        if (r < 0)
+                goto fail;
+
+        f->header = h;
+
+        if (!newly_created) {
+                set_clear_with_destructor(deferred_closes, journal_file_close);
+
+                r = journal_file_verify_header(f);
+                if (r < 0)
+                        goto fail;
+        }
+
+#if HAVE_GCRYPT
+        if (!newly_created && f->writable) {
+                r = journal_file_fss_load(f);
+                if (r < 0)
+                        goto fail;
+        }
+#endif
+
+        if (f->writable) {
+                if (metrics) {
+                        journal_default_metrics(metrics, f->fd);
+                        f->metrics = *metrics;
+                } else if (template)
+                        f->metrics = template->metrics;
+
+                r = journal_file_refresh_header(f);
+                if (r < 0)
+                        goto fail;
+        }
+
+#if HAVE_GCRYPT
+        r = journal_file_hmac_setup(f);
+        if (r < 0)
+                goto fail;
+#endif
+
+        if (newly_created) {
+                r = journal_file_setup_field_hash_table(f);
+                if (r < 0)
+                        goto fail;
+
+                r = journal_file_setup_data_hash_table(f);
+                if (r < 0)
+                        goto fail;
+
+#if HAVE_GCRYPT
+                r = journal_file_append_first_tag(f);
+                if (r < 0)
+                        goto fail;
+#endif
+        }
+
+        if (mmap_cache_got_sigbus(f->mmap, f->cache_fd)) {
+                r = -EIO;
+                goto fail;
+        }
+
+        if (template && template->post_change_timer) {
+                r = journal_file_enable_post_change_timer(
+                                f,
+                                sd_event_source_get_event(template->post_change_timer),
+                                template->post_change_timer_period);
+
+                if (r < 0)
+                        goto fail;
+        }
+
+        /* The file is opened now successfully, thus we take possession of any passed in fd. */
+        f->close_fd = true;
+
+        *ret = f;
+        return 0;
+
+fail:
+        if (f->cache_fd && mmap_cache_got_sigbus(f->mmap, f->cache_fd))
+                r = -EIO;
+
+        (void) journal_file_close(f);
+
+        return r;
+}
+
+int journal_file_archive(JournalFile *f) {
+        _cleanup_free_ char *p = NULL;
+
+        assert(f);
+
+        if (!f->writable)
+                return -EINVAL;
+
+        /* Is this a journal file that was passed to us as fd? If so, we synthesized a path name for it, and we refuse
+         * rotation, since we don't know the actual path, and couldn't rename the file hence. */
+        if (path_startswith(f->path, "/proc/self/fd"))
+                return -EINVAL;
+
+        if (!endswith(f->path, ".journal"))
+                return -EINVAL;
+
+        if (asprintf(&p, "%.*s@" SD_ID128_FORMAT_STR "-%016"PRIx64"-%016"PRIx64".journal",
+                     (int) strlen(f->path) - 8, f->path,
+                     SD_ID128_FORMAT_VAL(f->header->seqnum_id),
+                     le64toh(f->header->head_entry_seqnum),
+                     le64toh(f->header->head_entry_realtime)) < 0)
+                return -ENOMEM;
+
+        /* Try to rename the file to the archived version. If the file already was deleted, we'll get ENOENT, let's
+         * ignore that case. */
+        if (rename(f->path, p) < 0 && errno != ENOENT)
+                return -errno;
+
+        /* Sync the rename to disk */
+        (void) fsync_directory_of_file(f->fd);
+
+        /* Set as archive so offlining commits w/state=STATE_ARCHIVED. Previously we would set old_file->header->state
+         * to STATE_ARCHIVED directly here, but journal_file_set_offline() short-circuits when state != STATE_ONLINE,
+         * which would result in the rotated journal never getting fsync() called before closing.  Now we simply queue
+         * the archive state by setting an archive bit, leaving the state as STATE_ONLINE so proper offlining
+         * occurs. */
+        f->archive = true;
+
+        /* Currently, btrfs is not very good with out write patterns and fragments heavily. Let's defrag our journal
+         * files when we archive them */
+        f->defrag_on_close = true;
+
+        return 0;
+}
+
+JournalFile* journal_initiate_close(
+                JournalFile *f,
+                Set *deferred_closes) {
+
+        int r;
+
+        assert(f);
+
+        if (deferred_closes) {
+
+                r = set_put(deferred_closes, f);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to add file to deferred close set, closing immediately.");
+                else {
+                        (void) journal_file_set_offline(f, false);
+                        return NULL;
+                }
+        }
+
+        return journal_file_close(f);
+}
+
+int journal_file_rotate(
+                JournalFile **f,
+                bool compress,
+                uint64_t compress_threshold_bytes,
+                bool seal,
+                Set *deferred_closes) {
+
+        JournalFile *new_file = NULL;
+        int r;
+
+        assert(f);
+        assert(*f);
+
+        r = journal_file_archive(*f);
+        if (r < 0)
+                return r;
+
+        r = journal_file_open(
+                        -1,
+                        (*f)->path,
+                        (*f)->flags,
+                        (*f)->mode,
+                        compress,
+                        compress_threshold_bytes,
+                        seal,
+                        NULL,            /* metrics */
+                        (*f)->mmap,
+                        deferred_closes,
+                        *f,              /* template */
+                        &new_file);
+
+        journal_initiate_close(*f, deferred_closes);
+        *f = new_file;
+
+        return r;
+}
+
+int journal_file_dispose(int dir_fd, const char *fname) {
+        _cleanup_free_ char *p = NULL;
+        _cleanup_close_ int fd = -1;
+
+        assert(fname);
+
+        /* Renames a journal file to *.journal~, i.e. to mark it as corruped or otherwise uncleanly shutdown. Note that
+         * this is done without looking into the file or changing any of its contents. The idea is that this is called
+         * whenever something is suspicious and we want to move the file away and make clear that it is not accessed
+         * for writing anymore. */
+
+        if (!endswith(fname, ".journal"))
+                return -EINVAL;
+
+        if (asprintf(&p, "%.*s@%016" PRIx64 "-%016" PRIx64 ".journal~",
+                     (int) strlen(fname) - 8, fname,
+                     now(CLOCK_REALTIME),
+                     random_u64()) < 0)
+                return -ENOMEM;
+
+        if (renameat(dir_fd, fname, dir_fd, p) < 0)
+                return -errno;
+
+        /* btrfs doesn't cope well with our write pattern and fragments heavily. Let's defrag all files we rotate */
+        fd = openat(dir_fd, p, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+        if (fd < 0)
+                log_debug_errno(errno, "Failed to open file for defragmentation/FS_NOCOW_FL, ignoring: %m");
+        else {
+                (void) chattr_fd(fd, 0, FS_NOCOW_FL, NULL);
+                (void) btrfs_defrag_fd(fd);
+        }
+
+        return 0;
+}
+
+int journal_file_open_reliably(
+                const char *fname,
+                int flags,
+                mode_t mode,
+                bool compress,
+                uint64_t compress_threshold_bytes,
+                bool seal,
+                JournalMetrics *metrics,
+                MMapCache *mmap_cache,
+                Set *deferred_closes,
+                JournalFile *template,
+                JournalFile **ret) {
+
+        int r;
+
+        r = journal_file_open(-1, fname, flags, mode, compress, compress_threshold_bytes, seal, metrics, mmap_cache,
+                              deferred_closes, template, ret);
+        if (!IN_SET(r,
+                    -EBADMSG,           /* Corrupted */
+                    -ENODATA,           /* Truncated */
+                    -EHOSTDOWN,         /* Other machine */
+                    -EPROTONOSUPPORT,   /* Incompatible feature */
+                    -EBUSY,             /* Unclean shutdown */
+                    -ESHUTDOWN,         /* Already archived */
+                    -EIO,               /* IO error, including SIGBUS on mmap */
+                    -EIDRM,             /* File has been deleted */
+                    -ETXTBSY))          /* File is from the future */
+                return r;
+
+        if ((flags & O_ACCMODE) == O_RDONLY)
+                return r;
+
+        if (!(flags & O_CREAT))
+                return r;
+
+        if (!endswith(fname, ".journal"))
+                return r;
+
+        /* The file is corrupted. Rotate it away and try it again (but only once) */
+        log_warning_errno(r, "File %s corrupted or uncleanly shut down, renaming and replacing.", fname);
+
+        r = journal_file_dispose(AT_FDCWD, fname);
+        if (r < 0)
+                return r;
+
+        return journal_file_open(-1, fname, flags, mode, compress, compress_threshold_bytes, seal, metrics, mmap_cache,
+                                 deferred_closes, template, ret);
+}
+
+int journal_file_copy_entry(JournalFile *from, JournalFile *to, Object *o, uint64_t p) {
+        uint64_t i, n;
+        uint64_t q, xor_hash = 0;
+        int r;
+        EntryItem *items;
+        dual_timestamp ts;
+        const sd_id128_t *boot_id;
+
+        assert(from);
+        assert(to);
+        assert(o);
+        assert(p);
+
+        if (!to->writable)
+                return -EPERM;
+
+        ts.monotonic = le64toh(o->entry.monotonic);
+        ts.realtime = le64toh(o->entry.realtime);
+        boot_id = &o->entry.boot_id;
+
+        n = journal_file_entry_n_items(o);
+        /* alloca() can't take 0, hence let's allocate at least one */
+        items = newa(EntryItem, MAX(1u, n));
+
+        for (i = 0; i < n; i++) {
+                uint64_t l, h;
+                le64_t le_hash;
+                size_t t;
+                void *data;
+                Object *u;
+
+                q = le64toh(o->entry.items[i].object_offset);
+                le_hash = o->entry.items[i].hash;
+
+                r = journal_file_move_to_object(from, OBJECT_DATA, q, &o);
+                if (r < 0)
+                        return r;
+
+                if (le_hash != o->data.hash)
+                        return -EBADMSG;
+
+                l = le64toh(o->object.size) - offsetof(Object, data.payload);
+                t = (size_t) l;
+
+                /* We hit the limit on 32bit machines */
+                if ((uint64_t) t != l)
+                        return -E2BIG;
+
+                if (o->object.flags & OBJECT_COMPRESSION_MASK) {
+#if HAVE_XZ || HAVE_LZ4
+                        size_t rsize = 0;
+
+                        r = decompress_blob(o->object.flags & OBJECT_COMPRESSION_MASK,
+                                            o->data.payload, l, &from->compress_buffer, &from->compress_buffer_size, &rsize, 0);
+                        if (r < 0)
+                                return r;
+
+                        data = from->compress_buffer;
+                        l = rsize;
+#else
+                        return -EPROTONOSUPPORT;
+#endif
+                } else
+                        data = o->data.payload;
+
+                r = journal_file_append_data(to, data, l, &u, &h);
+                if (r < 0)
+                        return r;
+
+                xor_hash ^= le64toh(u->data.hash);
+                items[i].object_offset = htole64(h);
+                items[i].hash = u->data.hash;
+
+                r = journal_file_move_to_object(from, OBJECT_ENTRY, p, &o);
+                if (r < 0)
+                        return r;
+        }
+
+        r = journal_file_append_entry_internal(to, &ts, boot_id, xor_hash, items, n,
+                                               NULL, NULL, NULL);
+
+        if (mmap_cache_got_sigbus(to->mmap, to->cache_fd))
+                return -EIO;
+
+        return r;
+}
+
+void journal_reset_metrics(JournalMetrics *m) {
+        assert(m);
+
+        /* Set everything to "pick automatic values". */
+
+        *m = (JournalMetrics) {
+                .min_use = (uint64_t) -1,
+                .max_use = (uint64_t) -1,
+                .min_size = (uint64_t) -1,
+                .max_size = (uint64_t) -1,
+                .keep_free = (uint64_t) -1,
+                .n_max_files = (uint64_t) -1,
+        };
+}
+
+void journal_default_metrics(JournalMetrics *m, int fd) {
+        char a[FORMAT_BYTES_MAX], b[FORMAT_BYTES_MAX], c[FORMAT_BYTES_MAX], d[FORMAT_BYTES_MAX], e[FORMAT_BYTES_MAX];
+        struct statvfs ss;
+        uint64_t fs_size;
+
+        assert(m);
+        assert(fd >= 0);
+
+        if (fstatvfs(fd, &ss) >= 0)
+                fs_size = ss.f_frsize * ss.f_blocks;
+        else {
+                log_debug_errno(errno, "Failed to determine disk size: %m");
+                fs_size = 0;
+        }
+
+        if (m->max_use == (uint64_t) -1) {
+
+                if (fs_size > 0) {
+                        m->max_use = PAGE_ALIGN(fs_size / 10); /* 10% of file system size */
+
+                        if (m->max_use > DEFAULT_MAX_USE_UPPER)
+                                m->max_use = DEFAULT_MAX_USE_UPPER;
+
+                        if (m->max_use < DEFAULT_MAX_USE_LOWER)
+                                m->max_use = DEFAULT_MAX_USE_LOWER;
+                } else
+                        m->max_use = DEFAULT_MAX_USE_LOWER;
+        } else {
+                m->max_use = PAGE_ALIGN(m->max_use);
+
+                if (m->max_use != 0 && m->max_use < JOURNAL_FILE_SIZE_MIN*2)
+                        m->max_use = JOURNAL_FILE_SIZE_MIN*2;
+        }
+
+        if (m->min_use == (uint64_t) -1)
+                m->min_use = DEFAULT_MIN_USE;
+
+        if (m->min_use > m->max_use)
+                m->min_use = m->max_use;
+
+        if (m->max_size == (uint64_t) -1) {
+                m->max_size = PAGE_ALIGN(m->max_use / 8); /* 8 chunks */
+
+                if (m->max_size > DEFAULT_MAX_SIZE_UPPER)
+                        m->max_size = DEFAULT_MAX_SIZE_UPPER;
+        } else
+                m->max_size = PAGE_ALIGN(m->max_size);
+
+        if (m->max_size != 0) {
+                if (m->max_size < JOURNAL_FILE_SIZE_MIN)
+                        m->max_size = JOURNAL_FILE_SIZE_MIN;
+
+                if (m->max_use != 0 && m->max_size*2 > m->max_use)
+                        m->max_use = m->max_size*2;
+        }
+
+        if (m->min_size == (uint64_t) -1)
+                m->min_size = JOURNAL_FILE_SIZE_MIN;
+        else {
+                m->min_size = PAGE_ALIGN(m->min_size);
+
+                if (m->min_size < JOURNAL_FILE_SIZE_MIN)
+                        m->min_size = JOURNAL_FILE_SIZE_MIN;
+
+                if (m->max_size != 0 && m->min_size > m->max_size)
+                        m->max_size = m->min_size;
+        }
+
+        if (m->keep_free == (uint64_t) -1) {
+
+                if (fs_size > 0) {
+                        m->keep_free = PAGE_ALIGN(fs_size * 3 / 20); /* 15% of file system size */
+
+                        if (m->keep_free > DEFAULT_KEEP_FREE_UPPER)
+                                m->keep_free = DEFAULT_KEEP_FREE_UPPER;
+
+                } else
+                        m->keep_free = DEFAULT_KEEP_FREE;
+        }
+
+        if (m->n_max_files == (uint64_t) -1)
+                m->n_max_files = DEFAULT_N_MAX_FILES;
+
+        log_debug("Fixed min_use=%s max_use=%s max_size=%s min_size=%s keep_free=%s n_max_files=%" PRIu64,
+                  format_bytes(a, sizeof(a), m->min_use),
+                  format_bytes(b, sizeof(b), m->max_use),
+                  format_bytes(c, sizeof(c), m->max_size),
+                  format_bytes(d, sizeof(d), m->min_size),
+                  format_bytes(e, sizeof(e), m->keep_free),
+                  m->n_max_files);
+}
+
+int journal_file_get_cutoff_realtime_usec(JournalFile *f, usec_t *from, usec_t *to) {
+        assert(f);
+        assert(f->header);
+        assert(from || to);
+
+        if (from) {
+                if (f->header->head_entry_realtime == 0)
+                        return -ENOENT;
+
+                *from = le64toh(f->header->head_entry_realtime);
+        }
+
+        if (to) {
+                if (f->header->tail_entry_realtime == 0)
+                        return -ENOENT;
+
+                *to = le64toh(f->header->tail_entry_realtime);
+        }
+
+        return 1;
+}
+
+int journal_file_get_cutoff_monotonic_usec(JournalFile *f, sd_id128_t boot_id, usec_t *from, usec_t *to) {
+        Object *o;
+        uint64_t p;
+        int r;
+
+        assert(f);
+        assert(from || to);
+
+        r = find_data_object_by_boot_id(f, boot_id, &o, &p);
+        if (r <= 0)
+                return r;
+
+        if (le64toh(o->data.n_entries) <= 0)
+                return 0;
+
+        if (from) {
+                r = journal_file_move_to_object(f, OBJECT_ENTRY, le64toh(o->data.entry_offset), &o);
+                if (r < 0)
+                        return r;
+
+                *from = le64toh(o->entry.monotonic);
+        }
+
+        if (to) {
+                r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
+                if (r < 0)
+                        return r;
+
+                r = generic_array_get_plus_one(f,
+                                               le64toh(o->data.entry_offset),
+                                               le64toh(o->data.entry_array_offset),
+                                               le64toh(o->data.n_entries)-1,
+                                               &o, NULL);
+                if (r <= 0)
+                        return r;
+
+                *to = le64toh(o->entry.monotonic);
+        }
+
+        return 1;
+}
+
+bool journal_file_rotate_suggested(JournalFile *f, usec_t max_file_usec) {
+        assert(f);
+        assert(f->header);
+
+        /* If we gained new header fields we gained new features,
+         * hence suggest a rotation */
+        if (le64toh(f->header->header_size) < sizeof(Header)) {
+                log_debug("%s uses an outdated header, suggesting rotation.", f->path);
+                return true;
+        }
+
+        /* Let's check if the hash tables grew over a certain fill
+         * level (75%, borrowing this value from Java's hash table
+         * implementation), and if so suggest a rotation. To calculate
+         * the fill level we need the n_data field, which only exists
+         * in newer versions. */
+
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_data))
+                if (le64toh(f->header->n_data) * 4ULL > (le64toh(f->header->data_hash_table_size) / sizeof(HashItem)) * 3ULL) {
+                        log_debug("Data hash table of %s has a fill level at %.1f (%"PRIu64" of %"PRIu64" items, %llu file size, %"PRIu64" bytes per hash table item), suggesting rotation.",
+                                  f->path,
+                                  100.0 * (double) le64toh(f->header->n_data) / ((double) (le64toh(f->header->data_hash_table_size) / sizeof(HashItem))),
+                                  le64toh(f->header->n_data),
+                                  le64toh(f->header->data_hash_table_size) / sizeof(HashItem),
+                                  (unsigned long long) f->last_stat.st_size,
+                                  f->last_stat.st_size / le64toh(f->header->n_data));
+                        return true;
+                }
+
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_fields))
+                if (le64toh(f->header->n_fields) * 4ULL > (le64toh(f->header->field_hash_table_size) / sizeof(HashItem)) * 3ULL) {
+                        log_debug("Field hash table of %s has a fill level at %.1f (%"PRIu64" of %"PRIu64" items), suggesting rotation.",
+                                  f->path,
+                                  100.0 * (double) le64toh(f->header->n_fields) / ((double) (le64toh(f->header->field_hash_table_size) / sizeof(HashItem))),
+                                  le64toh(f->header->n_fields),
+                                  le64toh(f->header->field_hash_table_size) / sizeof(HashItem));
+                        return true;
+                }
+
+        /* Are the data objects properly indexed by field objects? */
+        if (JOURNAL_HEADER_CONTAINS(f->header, n_data) &&
+            JOURNAL_HEADER_CONTAINS(f->header, n_fields) &&
+            le64toh(f->header->n_data) > 0 &&
+            le64toh(f->header->n_fields) == 0)
+                return true;
+
+        if (max_file_usec > 0) {
+                usec_t t, h;
+
+                h = le64toh(f->header->head_entry_realtime);
+                t = now(CLOCK_REALTIME);
+
+                if (h > 0 && t > h + max_file_usec)
+                        return true;
+        }
+
+        return false;
+}