Merge branch 'mh/avoid-rewriting-packed-refs'
[gitweb.git] / refs / files-backend.c
index da8a98669778a4e81c489e6841482b9ab7526653..b956215bfc8ceb0a5c801163ea84df6a3336d3d5 100644 (file)
@@ -12,7 +12,7 @@
 
 struct ref_lock {
        char *ref_name;
-       struct lock_file *lk;
+       struct lock_file lk;
        struct object_id old_oid;
 };
 
@@ -106,15 +106,6 @@ static void files_reflog_path(struct files_ref_store *refs,
                              struct strbuf *sb,
                              const char *refname)
 {
-       if (!refname) {
-               /*
-                * FIXME: of course this is wrong in multi worktree
-                * setting. To be fixed real soon.
-                */
-               strbuf_addf(sb, "%s/logs", refs->gitcommondir);
-               return;
-       }
-
        switch (ref_type(refname)) {
        case REF_TYPE_PER_WORKTREE:
        case REF_TYPE_PSEUDOREF:
@@ -198,7 +189,7 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
                        if (!refs_resolve_ref_unsafe(&refs->base,
                                                     refname.buf,
                                                     RESOLVE_REF_READING,
-                                                    oid.hash, &flag)) {
+                                                    &oid, &flag)) {
                                oidclr(&oid);
                                flag |= REF_ISBROKEN;
                        } else if (is_null_oid(&oid)) {
@@ -270,7 +261,7 @@ static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
 }
 
 static int files_read_raw_ref(struct ref_store *ref_store,
-                             const char *refname, unsigned char *sha1,
+                             const char *refname, struct object_id *oid,
                              struct strbuf *referent, unsigned int *type)
 {
        struct files_ref_store *refs =
@@ -279,6 +270,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
        struct strbuf sb_path = STRBUF_INIT;
        const char *path;
        const char *buf;
+       const char *p;
        struct stat st;
        int fd;
        int ret = -1;
@@ -313,7 +305,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
                if (errno != ENOENT)
                        goto out;
                if (refs_read_raw_ref(refs->packed_ref_store, refname,
-                                     sha1, referent, type)) {
+                                     oid, referent, type)) {
                        errno = ENOENT;
                        goto out;
                }
@@ -353,7 +345,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
                 * packed ref:
                 */
                if (refs_read_raw_ref(refs->packed_ref_store, refname,
-                                     sha1, referent, type)) {
+                                     oid, referent, type)) {
                        errno = EISDIR;
                        goto out;
                }
@@ -399,8 +391,8 @@ static int files_read_raw_ref(struct ref_store *ref_store,
         * Please note that FETCH_HEAD has additional
         * data after the sha.
         */
-       if (get_sha1_hex(buf, sha1) ||
-           (buf[40] != '\0' && !isspace(buf[40]))) {
+       if (parse_oid_hex(buf, oid, &p) ||
+           (*p != '\0' && !isspace(*p))) {
                *type |= REF_ISBROKEN;
                errno = EINVAL;
                goto out;
@@ -418,9 +410,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
 
 static void unlock_ref(struct ref_lock *lock)
 {
-       /* Do not free lock->lk -- atexit() still looks at them */
-       if (lock->lk)
-               rollback_lock_file(lock->lk);
+       rollback_lock_file(&lock->lk);
        free(lock->ref_name);
        free(lock);
 }
@@ -534,11 +524,8 @@ static int lock_raw_ref(struct files_ref_store *refs,
                goto error_return;
        }
 
-       if (!lock->lk)
-               lock->lk = xcalloc(1, sizeof(struct lock_file));
-
        if (hold_lock_file_for_update_timeout(
-                           lock->lk, ref_file.buf, LOCK_NO_DEREF,
+                           &lock->lk, ref_file.buf, LOCK_NO_DEREF,
                            get_files_ref_lock_timeout_ms()) < 0) {
                if (errno == ENOENT && --attempts_remaining > 0) {
                        /*
@@ -559,7 +546,7 @@ static int lock_raw_ref(struct files_ref_store *refs,
         */
 
        if (files_read_raw_ref(&refs->base, refname,
-                              lock->old_oid.hash, referent, type)) {
+                              &lock->old_oid, referent, type)) {
                if (errno == ENOENT) {
                        if (mustexist) {
                                /* Garden variety missing reference. */
@@ -655,43 +642,6 @@ static int lock_raw_ref(struct files_ref_store *refs,
        return ret;
 }
 
-static int files_peel_ref(struct ref_store *ref_store,
-                         const char *refname, unsigned char *sha1)
-{
-       struct files_ref_store *refs =
-               files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
-                              "peel_ref");
-       int flag;
-       unsigned char base[20];
-
-       if (current_ref_iter && current_ref_iter->refname == refname) {
-               struct object_id peeled;
-
-               if (ref_iterator_peel(current_ref_iter, &peeled))
-                       return -1;
-               hashcpy(sha1, peeled.hash);
-               return 0;
-       }
-
-       if (refs_read_ref_full(ref_store, refname,
-                              RESOLVE_REF_READING, base, &flag))
-               return -1;
-
-       /*
-        * If the reference is packed, read its ref_entry from the
-        * cache in the hope that we already know its peeled value.
-        * We only try this optimization on packed references because
-        * (a) forcing the filling of the loose reference cache could
-        * be expensive and (b) loose references anyway usually do not
-        * have REF_KNOWS_PEELED.
-        */
-       if (flag & REF_ISPACKED &&
-           !refs_peel_ref(refs->packed_ref_store, refname, sha1))
-               return 0;
-
-       return peel_object(base, sha1);
-}
-
 struct files_ref_iterator {
        struct ref_iterator base;
 
@@ -762,7 +712,7 @@ static struct ref_iterator *files_ref_iterator_begin(
                const char *prefix, unsigned int flags)
 {
        struct files_ref_store *refs;
-       struct ref_iterator *loose_iter, *packed_iter;
+       struct ref_iterator *loose_iter, *packed_iter, *overlay_iter;
        struct files_ref_iterator *iter;
        struct ref_iterator *ref_iterator;
        unsigned int required_flags = REF_STORE_READ;
@@ -772,10 +722,6 @@ static struct ref_iterator *files_ref_iterator_begin(
 
        refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
 
-       iter = xcalloc(1, sizeof(*iter));
-       ref_iterator = &iter->base;
-       base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
-
        /*
         * We must make sure that all loose refs are read before
         * accessing the packed-refs file; this avoids a race
@@ -811,28 +757,34 @@ static struct ref_iterator *files_ref_iterator_begin(
                        refs->packed_ref_store, prefix, 0,
                        DO_FOR_EACH_INCLUDE_BROKEN);
 
-       iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
+       overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter);
+
+       iter = xcalloc(1, sizeof(*iter));
+       ref_iterator = &iter->base;
+       base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable,
+                              overlay_iter->ordered);
+       iter->iter0 = overlay_iter;
        iter->flags = flags;
 
        return ref_iterator;
 }
 
 /*
- * Verify that the reference locked by lock has the value old_sha1.
- * Fail if the reference doesn't exist and mustexist is set. Return 0
- * on success. On error, write an error message to err, set errno, and
- * return a negative value.
+ * Verify that the reference locked by lock has the value old_oid
+ * (unless it is NULL).  Fail if the reference doesn't exist and
+ * mustexist is set. Return 0 on success. On error, write an error
+ * message to err, set errno, and return a negative value.
  */
 static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
-                      const unsigned char *old_sha1, int mustexist,
+                      const struct object_id *old_oid, int mustexist,
                       struct strbuf *err)
 {
        assert(err);
 
        if (refs_read_ref_full(ref_store, lock->ref_name,
                               mustexist ? RESOLVE_REF_READING : 0,
-                              lock->old_oid.hash, NULL)) {
-               if (old_sha1) {
+                              &lock->old_oid, NULL)) {
+               if (old_oid) {
                        int save_errno = errno;
                        strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
                        errno = save_errno;
@@ -842,11 +794,11 @@ static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
                        return 0;
                }
        }
-       if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
+       if (old_oid && oidcmp(&lock->old_oid, old_oid)) {
                strbuf_addf(err, "ref '%s' is at %s but expected %s",
                            lock->ref_name,
                            oid_to_hex(&lock->old_oid),
-                           sha1_to_hex(old_sha1));
+                           oid_to_hex(old_oid));
                errno = EBUSY;
                return -1;
        }
@@ -876,22 +828,22 @@ static int create_reflock(const char *path, void *cb)
  * Locks a ref returning the lock on success and NULL on failure.
  * On failure errno is set to something meaningful.
  */
-static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
-                                           const char *refname,
-                                           const unsigned char *old_sha1,
-                                           const struct string_list *extras,
-                                           const struct string_list *skip,
-                                           unsigned int flags, int *type,
-                                           struct strbuf *err)
+static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
+                                          const char *refname,
+                                          const struct object_id *old_oid,
+                                          const struct string_list *extras,
+                                          const struct string_list *skip,
+                                          unsigned int flags, int *type,
+                                          struct strbuf *err)
 {
        struct strbuf ref_file = STRBUF_INIT;
        struct ref_lock *lock;
        int last_errno = 0;
-       int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
+       int mustexist = (old_oid && !is_null_oid(old_oid));
        int resolve_flags = RESOLVE_REF_NO_RECURSE;
        int resolved;
 
-       files_assert_main_repository(refs, "lock_ref_sha1_basic");
+       files_assert_main_repository(refs, "lock_ref_oid_basic");
        assert(err);
 
        lock = xcalloc(1, sizeof(struct ref_lock));
@@ -904,7 +856,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
        files_ref_path(refs, &ref_file, refname);
        resolved = !!refs_resolve_ref_unsafe(&refs->base,
                                             refname, resolve_flags,
-                                            lock->old_oid.hash, type);
+                                            &lock->old_oid, type);
        if (!resolved && errno == EISDIR) {
                /*
                 * we are trying to lock foo but we used to
@@ -923,7 +875,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
                }
                resolved = !!refs_resolve_ref_unsafe(&refs->base,
                                                     refname, resolve_flags,
-                                                    lock->old_oid.hash, type);
+                                                    &lock->old_oid, type);
        }
        if (!resolved) {
                last_errno = errno;
@@ -949,17 +901,15 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
                goto error_return;
        }
 
-       lock->lk = xcalloc(1, sizeof(struct lock_file));
-
        lock->ref_name = xstrdup(refname);
 
-       if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) {
+       if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) {
                last_errno = errno;
                unable_to_lock_message(ref_file.buf, errno, err);
                goto error_return;
        }
 
-       if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) {
+       if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) {
                last_errno = errno;
                goto error_return;
        }
@@ -977,7 +927,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 
 struct ref_to_prune {
        struct ref_to_prune *next;
-       unsigned char sha1[20];
+       struct object_id oid;
        char name[FLEX_ARRAY];
 };
 
@@ -1045,7 +995,7 @@ static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 
        transaction = ref_store_transaction_begin(&refs->base, &err);
        if (!transaction ||
-           ref_transaction_delete(transaction, r->name, r->sha1,
+           ref_transaction_delete(transaction, r->name, &r->oid,
                                   REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
            ref_transaction_commit(transaction, &err)) {
                ref_transaction_free(transaction);
@@ -1130,7 +1080,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
                 * packed-refs transaction:
                 */
                if (ref_transaction_update(transaction, iter->refname,
-                                          iter->oid->hash, NULL,
+                                          iter->oid, NULL,
                                           REF_NODEREF, NULL, &err))
                        die("failure preparing to create packed reference %s: %s",
                            iter->refname, err.buf);
@@ -1139,7 +1089,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
                if ((flags & PACK_REFS_PRUNE)) {
                        struct ref_to_prune *n;
                        FLEX_ALLOC_STR(n, name, iter->refname);
-                       hashcpy(n->sha1, iter->oid->hash);
+                       oidcpy(&n->oid, iter->oid);
                        n->next = refs_to_prune;
                        refs_to_prune = n;
                }
@@ -1274,9 +1224,9 @@ static int commit_ref_update(struct files_ref_store *refs,
                             const struct object_id *oid, const char *logmsg,
                             struct strbuf *err);
 
-static int files_rename_ref(struct ref_store *ref_store,
+static int files_copy_or_rename_ref(struct ref_store *ref_store,
                            const char *oldrefname, const char *newrefname,
-                           const char *logmsg)
+                           const char *logmsg, int copy)
 {
        struct files_ref_store *refs =
                files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
@@ -1302,14 +1252,18 @@ static int files_rename_ref(struct ref_store *ref_store,
 
        if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
                                     RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-                               orig_oid.hash, &flag)) {
+                               &orig_oid, &flag)) {
                ret = error("refname %s not found", oldrefname);
                goto out;
        }
 
        if (flag & REF_ISSYMREF) {
-               ret = error("refname %s is a symbolic ref, renaming it is not supported",
-                           oldrefname);
+               if (copy)
+                       ret = error("refname %s is a symbolic ref, copying it is not supported",
+                                   oldrefname);
+               else
+                       ret = error("refname %s is a symbolic ref, renaming it is not supported",
+                                   oldrefname);
                goto out;
        }
        if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
@@ -1317,14 +1271,20 @@ static int files_rename_ref(struct ref_store *ref_store,
                goto out;
        }
 
-       if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
+       if (!copy && log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
                ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
                            oldrefname, strerror(errno));
                goto out;
        }
 
-       if (refs_delete_ref(&refs->base, logmsg, oldrefname,
-                           orig_oid.hash, REF_NODEREF)) {
+       if (copy && log && copy_file(tmp_renamed_log.buf, sb_oldref.buf, 0644)) {
+               ret = error("unable to copy logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
+                           oldrefname, strerror(errno));
+               goto out;
+       }
+
+       if (!copy && refs_delete_ref(&refs->base, logmsg, oldrefname,
+                           &orig_oid, REF_NODEREF)) {
                error("unable to delete old %s", oldrefname);
                goto rollback;
        }
@@ -1336,9 +1296,9 @@ static int files_rename_ref(struct ref_store *ref_store,
         * the safety anyway; we want to delete the reference whatever
         * its current value.
         */
-       if (!refs_read_ref_full(&refs->base, newrefname,
+       if (!copy && !refs_read_ref_full(&refs->base, newrefname,
                                RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-                               oid.hash, NULL) &&
+                               &oid, NULL) &&
            refs_delete_ref(&refs->base, NULL, newrefname,
                            NULL, REF_NODEREF)) {
                if (errno == EISDIR) {
@@ -1364,10 +1324,13 @@ static int files_rename_ref(struct ref_store *ref_store,
 
        logmoved = log;
 
-       lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
-                                  REF_NODEREF, NULL, &err);
+       lock = lock_ref_oid_basic(refs, newrefname, NULL, NULL, NULL,
+                                 REF_NODEREF, NULL, &err);
        if (!lock) {
-               error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
+               if (copy)
+                       error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf);
+               else
+                       error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
                strbuf_release(&err);
                goto rollback;
        }
@@ -1384,8 +1347,8 @@ static int files_rename_ref(struct ref_store *ref_store,
        goto out;
 
  rollback:
-       lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
-                                  REF_NODEREF, NULL, &err);
+       lock = lock_ref_oid_basic(refs, oldrefname, NULL, NULL, NULL,
+                                 REF_NODEREF, NULL, &err);
        if (!lock) {
                error("unable to lock %s for rollback: %s", oldrefname, err.buf);
                strbuf_release(&err);
@@ -1418,16 +1381,32 @@ static int files_rename_ref(struct ref_store *ref_store,
        return ret;
 }
 
-static int close_ref(struct ref_lock *lock)
+static int files_rename_ref(struct ref_store *ref_store,
+                           const char *oldrefname, const char *newrefname,
+                           const char *logmsg)
 {
-       if (close_lock_file(lock->lk))
+       return files_copy_or_rename_ref(ref_store, oldrefname,
+                                newrefname, logmsg, 0);
+}
+
+static int files_copy_ref(struct ref_store *ref_store,
+                           const char *oldrefname, const char *newrefname,
+                           const char *logmsg)
+{
+       return files_copy_or_rename_ref(ref_store, oldrefname,
+                                newrefname, logmsg, 1);
+}
+
+static int close_ref_gently(struct ref_lock *lock)
+{
+       if (close_lock_file_gently(&lock->lk))
                return -1;
        return 0;
 }
 
 static int commit_ref(struct ref_lock *lock)
 {
-       char *path = get_locked_file_path(lock->lk);
+       char *path = get_locked_file_path(&lock->lk);
        struct stat st;
 
        if (!lstat(path, &st) && S_ISDIR(st.st_mode)) {
@@ -1451,7 +1430,7 @@ static int commit_ref(struct ref_lock *lock)
                free(path);
        }
 
-       if (commit_lock_file(lock->lk))
+       if (commit_lock_file(&lock->lk))
                return -1;
        return 0;
 }
@@ -1565,7 +1544,7 @@ static int log_ref_write_fd(int fd, const struct object_id *old_oid,
 
        written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
        free(logrec);
-       if (written != len)
+       if (written < 0)
                return -1;
 
        return 0;
@@ -1643,12 +1622,12 @@ static int write_ref_to_lockfile(struct ref_lock *lock,
                unlock_ref(lock);
                return -1;
        }
-       fd = get_lock_file_fd(lock->lk);
-       if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
-           write_in_full(fd, &term, 1) != 1 ||
-           close_ref(lock) < 0) {
+       fd = get_lock_file_fd(&lock->lk);
+       if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) < 0 ||
+           write_in_full(fd, &term, 1) < 0 ||
+           close_ref_gently(lock) < 0) {
                strbuf_addf(err,
-                           "couldn't write '%s'", get_lock_file_path(lock->lk));
+                           "couldn't write '%s'", get_lock_file_path(&lock->lk));
                unlock_ref(lock);
                return -1;
        }
@@ -1692,13 +1671,12 @@ static int commit_ref_update(struct files_ref_store *refs,
                 * check with HEAD only which should cover 99% of all usage
                 * scenarios (even 100% of the default ones).
                 */
-               struct object_id head_oid;
                int head_flag;
                const char *head_ref;
 
                head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
                                                   RESOLVE_REF_READING,
-                                                  head_oid.hash, &head_flag);
+                                                  NULL, &head_flag);
                if (head_ref && (head_flag & REF_ISSYMREF) &&
                    !strcmp(head_ref, lock->ref_name)) {
                        struct strbuf log_err = STRBUF_INIT;
@@ -1725,7 +1703,7 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target)
 {
        int ret = -1;
 #ifndef NO_SYMLINK_HEAD
-       char *ref_path = get_locked_file_path(lock->lk);
+       char *ref_path = get_locked_file_path(&lock->lk);
        unlink(ref_path);
        ret = symlink(target, ref_path);
        free(ref_path);
@@ -1744,7 +1722,7 @@ static void update_symref_reflog(struct files_ref_store *refs,
        struct object_id new_oid;
        if (logmsg &&
            !refs_read_ref_full(&refs->base, target,
-                               RESOLVE_REF_READING, new_oid.hash, NULL) &&
+                               RESOLVE_REF_READING, &new_oid, NULL) &&
            files_log_ref_write(refs, refname, &lock->old_oid,
                                &new_oid, logmsg, 0, &err)) {
                error("%s", err.buf);
@@ -1761,14 +1739,14 @@ static int create_symref_locked(struct files_ref_store *refs,
                return 0;
        }
 
-       if (!fdopen_lock_file(lock->lk, "w"))
+       if (!fdopen_lock_file(&lock->lk, "w"))
                return error("unable to fdopen %s: %s",
-                            lock->lk->tempfile.filename.buf, strerror(errno));
+                            lock->lk.tempfile->filename.buf, strerror(errno));
 
        update_symref_reflog(refs, lock, refname, target, logmsg);
 
        /* no error check; commit_ref will check ferror */
-       fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
+       fprintf(lock->lk.tempfile->fp, "ref: %s\n", target);
        if (commit_ref(lock) < 0)
                return error("unable to write symref for %s: %s", refname,
                             strerror(errno));
@@ -1785,9 +1763,9 @@ static int files_create_symref(struct ref_store *ref_store,
        struct ref_lock *lock;
        int ret;
 
-       lock = lock_ref_sha1_basic(refs, refname, NULL,
-                                  NULL, NULL, REF_NODEREF, NULL,
-                                  &err);
+       lock = lock_ref_oid_basic(refs, refname, NULL,
+                                 NULL, NULL, REF_NODEREF, NULL,
+                                 &err);
        if (!lock) {
                error("%s", err.buf);
                strbuf_release(&err);
@@ -2033,7 +2011,7 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 
                if (refs_read_ref_full(iter->ref_store,
                                       diter->relative_path, 0,
-                                      iter->oid.hash, &flags)) {
+                                      &iter->oid, &flags)) {
                        error("bad ref for %s", diter->path.buf);
                        continue;
                }
@@ -2075,23 +2053,64 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
        files_reflog_iterator_abort
 };
 
-static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
+static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
+                                                 const char *gitdir)
 {
-       struct files_ref_store *refs =
-               files_downcast(ref_store, REF_STORE_READ,
-                              "reflog_iterator_begin");
        struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
        struct ref_iterator *ref_iterator = &iter->base;
        struct strbuf sb = STRBUF_INIT;
 
-       base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-       files_reflog_path(refs, &sb, NULL);
+       base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
+       strbuf_addf(&sb, "%s/logs", gitdir);
        iter->dir_iterator = dir_iterator_begin(sb.buf);
        iter->ref_store = ref_store;
        strbuf_release(&sb);
+
        return ref_iterator;
 }
 
+static enum iterator_selection reflog_iterator_select(
+       struct ref_iterator *iter_worktree,
+       struct ref_iterator *iter_common,
+       void *cb_data)
+{
+       if (iter_worktree) {
+               /*
+                * We're a bit loose here. We probably should ignore
+                * common refs if they are accidentally added as
+                * per-worktree refs.
+                */
+               return ITER_SELECT_0;
+       } else if (iter_common) {
+               if (ref_type(iter_common->refname) == REF_TYPE_NORMAL)
+                       return ITER_SELECT_1;
+
+               /*
+                * The main ref store may contain main worktree's
+                * per-worktree refs, which should be ignored
+                */
+               return ITER_SKIP_1;
+       } else
+               return ITER_DONE;
+}
+
+static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
+{
+       struct files_ref_store *refs =
+               files_downcast(ref_store, REF_STORE_READ,
+                              "reflog_iterator_begin");
+
+       if (!strcmp(refs->gitdir, refs->gitcommondir)) {
+               return reflog_iterator_begin(ref_store, refs->gitcommondir);
+       } else {
+               return merge_ref_iterator_begin(
+                       0,
+                       reflog_iterator_begin(ref_store, refs->gitdir),
+                       reflog_iterator_begin(ref_store, refs->gitcommondir),
+                       reflog_iterator_select, refs);
+       }
+}
+
 /*
  * If update is a direct update of head_ref (the reference pointed to
  * by HEAD), then add an extra REF_LOG_ONLY update for HEAD.
@@ -2115,11 +2134,10 @@ static int split_head_update(struct ref_update *update,
 
        /*
         * First make sure that HEAD is not already in the
-        * transaction. This insertion is O(N) in the transaction
+        * transaction. This check is O(lg N) in the transaction
         * size, but it happens at most once per transaction.
         */
-       item = string_list_insert(affected_refnames, "HEAD");
-       if (item->util) {
+       if (string_list_has_string(affected_refnames, "HEAD")) {
                /* An entry already existed */
                strbuf_addf(err,
                            "multiple updates for 'HEAD' (including one "
@@ -2131,9 +2149,17 @@ static int split_head_update(struct ref_update *update,
        new_update = ref_transaction_add_update(
                        transaction, "HEAD",
                        update->flags | REF_LOG_ONLY | REF_NODEREF,
-                       update->new_oid.hash, update->old_oid.hash,
+                       &update->new_oid, &update->old_oid,
                        update->msg);
 
+       /*
+        * Add "HEAD". This insertion is O(N) in the transaction
+        * size, but it happens at most once per transaction.
+        * Add new_update->refname instead of a literal "HEAD".
+        */
+       if (strcmp(new_update->refname, "HEAD"))
+               BUG("%s unexpectedly not 'HEAD'", new_update->refname);
+       item = string_list_insert(affected_refnames, new_update->refname);
        item->util = new_update;
 
        return 0;
@@ -2160,13 +2186,12 @@ static int split_symref_update(struct files_ref_store *refs,
 
        /*
         * First make sure that referent is not already in the
-        * transaction. This insertion is O(N) in the transaction
+        * transaction. This check is O(lg N) in the transaction
         * size, but it happens at most once per symref in a
         * transaction.
         */
-       item = string_list_insert(affected_refnames, referent);
-       if (item->util) {
-               /* An entry already existed */
+       if (string_list_has_string(affected_refnames, referent)) {
+               /* An entry already exists */
                strbuf_addf(err,
                            "multiple updates for '%s' (including one "
                            "via symref '%s') are not allowed",
@@ -2188,7 +2213,7 @@ static int split_symref_update(struct files_ref_store *refs,
 
        new_update = ref_transaction_add_update(
                        transaction, referent, new_flags,
-                       update->new_oid.hash, update->old_oid.hash,
+                       &update->new_oid, &update->old_oid,
                        update->msg);
 
        new_update->parent_update = update;
@@ -2201,6 +2226,17 @@ static int split_symref_update(struct files_ref_store *refs,
        update->flags |= REF_LOG_ONLY | REF_NODEREF;
        update->flags &= ~REF_HAVE_OLD;
 
+       /*
+        * Add the referent. This insertion is O(N) in the transaction
+        * size, but it happens at most once per symref in a
+        * transaction. Make sure to add new_update->refname, which will
+        * be valid as long as affected_refnames is in use, and NOT
+        * referent, which might soon be freed by our caller.
+        */
+       item = string_list_insert(affected_refnames, new_update->refname);
+       if (item->util)
+               BUG("%s unexpectedly found in affected_refnames",
+                   new_update->refname);
        item->util = new_update;
 
        return 0;
@@ -2272,7 +2308,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
        struct strbuf referent = STRBUF_INIT;
        int mustexist = (update->flags & REF_HAVE_OLD) &&
                !is_null_oid(&update->old_oid);
-       int ret;
+       int ret = 0;
        struct ref_lock *lock;
 
        files_assert_main_repository(refs, "lock_ref_for_update");
@@ -2284,7 +2320,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
                ret = split_head_update(update, transaction, head_ref,
                                        affected_refnames, err);
                if (ret)
-                       return ret;
+                       goto out;
        }
 
        ret = lock_raw_ref(refs, update->refname, mustexist,
@@ -2298,7 +2334,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
                strbuf_addf(err, "cannot lock ref '%s': %s",
                            original_update_refname(update), reason);
                free(reason);
-               return ret;
+               goto out;
        }
 
        update->backend_data = lock;
@@ -2312,15 +2348,17 @@ static int lock_ref_for_update(struct files_ref_store *refs,
                         */
                        if (refs_read_ref_full(&refs->base,
                                               referent.buf, 0,
-                                              lock->old_oid.hash, NULL)) {
+                                              &lock->old_oid, NULL)) {
                                if (update->flags & REF_HAVE_OLD) {
                                        strbuf_addf(err, "cannot lock ref '%s': "
                                                    "error reading reference",
                                                    original_update_refname(update));
-                                       return -1;
+                                       ret = TRANSACTION_GENERIC_ERROR;
+                                       goto out;
                                }
                        } else if (check_old_oid(update, &lock->old_oid, err)) {
-                               return TRANSACTION_GENERIC_ERROR;
+                               ret = TRANSACTION_GENERIC_ERROR;
+                               goto out;
                        }
                } else {
                        /*
@@ -2334,13 +2372,15 @@ static int lock_ref_for_update(struct files_ref_store *refs,
                                                  referent.buf, transaction,
                                                  affected_refnames, err);
                        if (ret)
-                               return ret;
+                               goto out;
                }
        } else {
                struct ref_update *parent_update;
 
-               if (check_old_oid(update, &lock->old_oid, err))
-                       return TRANSACTION_GENERIC_ERROR;
+               if (check_old_oid(update, &lock->old_oid, err)) {
+                       ret = TRANSACTION_GENERIC_ERROR;
+                       goto out;
+               }
 
                /*
                 * If this update is happening indirectly because of a
@@ -2377,7 +2417,8 @@ static int lock_ref_for_update(struct files_ref_store *refs,
                                    "cannot update ref '%s': %s",
                                    update->refname, write_err);
                        free(write_err);
-                       return TRANSACTION_GENERIC_ERROR;
+                       ret = TRANSACTION_GENERIC_ERROR;
+                       goto out;
                } else {
                        update->flags |= REF_NEEDS_COMMIT;
                }
@@ -2388,13 +2429,17 @@ static int lock_ref_for_update(struct files_ref_store *refs,
                 * the lockfile is still open. Close it to
                 * free up the file descriptor:
                 */
-               if (close_ref(lock)) {
+               if (close_ref_gently(lock)) {
                        strbuf_addf(err, "couldn't close '%s.lock'",
                                    update->refname);
-                       return TRANSACTION_GENERIC_ERROR;
+                       ret = TRANSACTION_GENERIC_ERROR;
+                       goto out;
                }
        }
-       return 0;
+
+out:
+       strbuf_release(&referent);
+       return ret;
 }
 
 struct files_transaction_backend_data {
@@ -2450,7 +2495,6 @@ static int files_transaction_prepare(struct ref_store *ref_store,
        struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
        char *head_ref = NULL;
        int head_type;
-       struct object_id head_oid;
        struct files_transaction_backend_data *backend_data;
        struct ref_transaction *packed_transaction = NULL;
 
@@ -2507,7 +2551,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
         */
        head_ref = refs_resolve_refdup(ref_store, "HEAD",
                                       RESOLVE_REF_NO_RECURSE,
-                                      head_oid.hash, &head_type);
+                                      NULL, &head_type);
 
        if (head_ref && !(head_type & REF_ISSYMREF)) {
                FREE_AND_NULL(head_ref);
@@ -2527,7 +2571,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
                ret = lock_ref_for_update(refs, update, transaction,
                                          head_ref, &affected_refnames, err);
                if (ret)
-                       break;
+                       goto cleanup;
 
                if (update->flags & REF_DELETING &&
                    !(update->flags & REF_LOG_ONLY) &&
@@ -2551,7 +2595,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
                        ref_transaction_add_update(
                                        packed_transaction, update->refname,
                                        update->flags & ~REF_HAVE_OLD,
-                                       update->new_oid.hash, update->old_oid.hash,
+                                       &update->new_oid, &update->old_oid,
                                        NULL);
                }
        }
@@ -2820,7 +2864,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
                 */
                ref_transaction_add_update(packed_transaction, update->refname,
                                           update->flags & ~REF_HAVE_OLD,
-                                          update->new_oid.hash, update->old_oid.hash,
+                                          &update->new_oid, &update->old_oid,
                                           NULL);
        }
 
@@ -2881,7 +2925,7 @@ static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
 }
 
 static int files_reflog_expire(struct ref_store *ref_store,
-                              const char *refname, const unsigned char *sha1,
+                              const char *refname, const struct object_id *oid,
                               unsigned int flags,
                               reflog_expiry_prepare_fn prepare_fn,
                               reflog_expiry_should_prune_fn should_prune_fn,
@@ -2898,7 +2942,6 @@ static int files_reflog_expire(struct ref_store *ref_store,
        int status = 0;
        int type;
        struct strbuf err = STRBUF_INIT;
-       struct object_id oid;
 
        memset(&cb, 0, sizeof(cb));
        cb.flags = flags;
@@ -2910,9 +2953,9 @@ static int files_reflog_expire(struct ref_store *ref_store,
         * reference itself, plus we might need to update the
         * reference if --updateref was specified:
         */
-       lock = lock_ref_sha1_basic(refs, refname, sha1,
-                                  NULL, NULL, REF_NODEREF,
-                                  &type, &err);
+       lock = lock_ref_oid_basic(refs, refname, oid,
+                                 NULL, NULL, REF_NODEREF,
+                                 &type, &err);
        if (!lock) {
                error("cannot lock ref '%s': %s", refname, err.buf);
                strbuf_release(&err);
@@ -2948,9 +2991,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
                }
        }
 
-       hashcpy(oid.hash, sha1);
-
-       (*prepare_fn)(refname, &oid, cb.policy_cb);
+       (*prepare_fn)(refname, oid, cb.policy_cb);
        refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
        (*cleanup_fn)(cb.policy_cb);
 
@@ -2966,16 +3007,17 @@ static int files_reflog_expire(struct ref_store *ref_store,
                        !(type & REF_ISSYMREF) &&
                        !is_null_oid(&cb.last_kept_oid);
 
-               if (close_lock_file(&reflog_lock)) {
+               if (close_lock_file_gently(&reflog_lock)) {
                        status |= error("couldn't write %s: %s", log_file,
                                        strerror(errno));
+                       rollback_lock_file(&reflog_lock);
                } else if (update &&
-                          (write_in_full(get_lock_file_fd(lock->lk),
-                               oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ ||
-                           write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 ||
-                           close_ref(lock) < 0)) {
+                          (write_in_full(get_lock_file_fd(&lock->lk),
+                               oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) < 0 ||
+                           write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
+                           close_ref_gently(lock) < 0)) {
                        status |= error("couldn't write %s",
-                                       get_lock_file_path(lock->lk));
+                                       get_lock_file_path(&lock->lk));
                        rollback_lock_file(&reflog_lock);
                } else if (commit_lock_file(&reflog_lock)) {
                        status |= error("unable to write reflog '%s' (%s)",
@@ -3026,10 +3068,10 @@ struct ref_storage_be refs_be_files = {
        files_initial_transaction_commit,
 
        files_pack_refs,
-       files_peel_ref,
        files_create_symref,
        files_delete_refs,
        files_rename_ref,
+       files_copy_ref,
 
        files_ref_iterator_begin,
        files_read_raw_ref,