Change the sync behavior to fit the LTFS format Spec 2.5 (#461)

Author: Atsushi Abe

src/iosched/unified.c

@@ -2291,6 +2291,7 @@ int _unified_write_index_after_perm(int write_ret, struct unified_data *priv)
 		return ret;
 	}
 
+	ltfs_set_commit_message_reason(SYNC_WRITE_PERM, priv->vol);
 	ret = ltfs_write_index(ltfs_ip_id(priv->vol), SYNC_WRITE_PERM, priv->vol);
 
 	return ret;

src/libltfs/ltfs.c

@@ -1779,6 +1779,7 @@ int ltfs_mount(bool force_full, bool deep_recovery, bool recover_extra, bool rec
 				}
 				INTERRUPTED_GOTO(ret, out_unlock);
 				ltfsmsg(LTFS_INFO, 11022I);
+				ltfs_set_commit_message_reason(SYNC_RECOVERY, vol);
 				ret = ltfs_write_index(vol->label->partid_ip, SYNC_RECOVERY, vol);
 				if (ret < 0)
 					goto out_unlock;
@@ -1864,13 +1865,6 @@ int ltfs_mount(bool force_full, bool deep_recovery, bool recover_extra, bool rec
 	if (vol->index->uid_number == 0)
 		ltfsmsg(LTFS_WARN, 11307W, vol->label->vol_uuid);
 
-	/* Clear the commit message so it doesn't carry over from the previous session */
-	/* TODO: is this the right place to clear the commit message? */
-	if (vol->index->commit_message) {
-		free(vol->index->commit_message);
-		vol->index->commit_message = NULL;
-	}
-
 	/* If we reach this point, both partitions end in an index file. */
 	vol->ip_index_file_end = true;
 	vol->dp_index_file_end = true;
@@ -2535,6 +2529,7 @@ int ltfs_write_index(char partition, char *reason, struct ltfs_volume *vol)
 
 			write_perm = true;
 			reason = SYNC_WRITE_PERM;
+			ltfs_set_commit_message_reason(SYNC_WRITE_PERM, vol);
 		}
 		/* ignore return value: we want to keep trying even if, e.g., the DP fills up */
 	}
@@ -3137,6 +3132,7 @@ int ltfs_format_tape(struct ltfs_volume *vol, int density_code, bool destructive
 	if (ret < 0)
 		return ret;
 	ltfsmsg(LTFS_INFO, 11278I, vol->label->partid_dp); /* "Writing Index to ..." */
+	ltfs_set_commit_message_reason(SYNC_FORMAT, vol);
 	ret = ltfs_write_index(vol->label->partid_dp, SYNC_FORMAT, vol);
 	if (ret < 0) {
 		ltfsmsg(LTFS_ERR, 11279E, vol->label->partid_dp, ret);
@@ -3633,6 +3629,7 @@ int ltfs_sync_index(char *reason, bool index_locking, struct ltfs_volume *vol)
 			 *       For now, write the same index on IP and return an error against a sync
 			 *       request.
 			 */
+			ltfs_set_commit_message_reason(SYNC_WRITE_PERM, vol);
 			ret_r = ltfs_write_index(ltfs_ip_id(vol), SYNC_WRITE_PERM, vol);
 			if (!ret_r) {
 				ltfsmsg(LTFS_INFO, 11344I, bc_print);
@@ -4634,3 +4631,61 @@ int ltfs_build_fullpath(char **dest, struct dentry *d)
 
 	return ret;
 }
+
+/**
+ * Update commit message of index to the prefixed message based on sync reason.
+ * @param reason sync reason defined in ltfs.h
+ * @param vol LTFS colume
+ */
+void ltfs_set_commit_message_reason(char *reason, struct ltfs_volume *vol)
+{
+	ltfs_mutex_lock(&vol->index->dirty_lock);
+	ltfs_set_commit_message_reason_unlocked(reason, vol);
+	ltfs_mutex_unlock(&vol->index->dirty_lock);
+
+	return;
+}
+
+/**
+ * Update commit message of index to the prefixed message based on sync reason. Caller need to
+ * take index->dirty_lock before calling this function.
+ * @param reason sync reason defined in ltfs.h
+ * @param vol LTFS volume
+ */
+void ltfs_set_commit_message_reason_unlocked(char *reason, struct ltfs_volume *vol)
+{
+	bool dirty = false;
+	int ret = 0;
+	char *str_now = NULL, *msg = NULL;
+	struct ltfs_timespec now;
+
+	if (!vol->index->dirty) {
+		/* Do nothing because no update was made */
+		goto out;
+	}
+
+	if (vol->index->commit_message) {
+		free(vol->index->commit_message);
+		dirty = true;
+	}
+
+	ret = get_current_timespec(&now);
+	if (ret)
+		goto out;
+
+	ret = xml_format_time(now, &str_now);
+	if (ret)
+		goto out;
+
+	ret = asprintf(&msg, "%s - %s", reason, str_now);
+	if (ret) {
+		vol->index->commit_message = msg;
+		dirty = true;
+	}
+
+out:
+	if (dirty)
+		ltfs_set_index_dirty(false, false, vol->index);
+
+	return;
+}

src/libltfs/ltfs.h

@@ -730,6 +730,9 @@ int ltfs_profiler_set(uint64_t source, struct ltfs_volume *vol);
 int ltfs_get_rao_list(char *path, struct ltfs_volume *vol);
 int ltfs_build_fullpath(char **dest, struct dentry *d);
 
+void ltfs_set_commit_message_reason(char *reason, struct ltfs_volume *vol);
+void ltfs_set_commit_message_reason_unlocked(char *reason, struct ltfs_volume *vol);
+
 #ifdef __cplusplus
 }
 #endif

src/libltfs/ltfs_fsops.c

@@ -2106,6 +2106,10 @@ int ltfs_fsops_volume_sync(char *reason, struct ltfs_volume *vol)
 	if (ret < 0)
 		return ret;
 
+	ltfs_mutex_lock(&vol->index->dirty_lock);
+	ltfs_set_commit_message_reason_unlocked(reason, vol);
+	ltfs_mutex_unlock(&vol->index->dirty_lock);
+
 	ret = ltfs_sync_index(reason, true, vol);
 
 	return ret;

src/libltfs/ltfs_internal.c

@@ -1323,6 +1323,7 @@ int ltfs_check_medium(bool fix, bool deep, bool recover_extra, bool recover_syml
 				}
 			}
 			/* write to data partition if it doesn't end in an index file */
+			ltfs_set_commit_message_reason(SYNC_RECOVERY, vol);
 			if (! dp_have_index || dp_blocks_after) {
 				ltfsmsg(LTFS_INFO, 17259I, "DP", vol->index->selfptr.partition, (unsigned long long)vol->index->selfptr.block);
 				ret = ltfs_write_index(vol->label->partid_dp, SYNC_RECOVERY, vol);
@@ -1407,12 +1408,15 @@ int ltfs_write_index_conditional(char partition, struct ltfs_volume *vol)
 
 	CHECK_ARG_NULL(vol, -LTFS_NULL_ARG);
 
-	if (partition == ltfs_ip_id(vol) && ! vol->ip_index_file_end)
+	if (partition == ltfs_ip_id(vol) && ! vol->ip_index_file_end) {
+		ltfs_set_commit_message_reason(SYNC_CASCHE_PRESSURE, vol);
 		ret = ltfs_write_index(partition, SYNC_CASCHE_PRESSURE, vol);
-	else if (partition == ltfs_dp_id(vol) &&
+	} else if (partition == ltfs_dp_id(vol) &&
 	         (! vol->dp_index_file_end ||
-	          (vol->ip_index_file_end && vol->index->selfptr.partition == ltfs_ip_id(vol))))
+	          (vol->ip_index_file_end && vol->index->selfptr.partition == ltfs_ip_id(vol)))) {
+		ltfs_set_commit_message_reason(SYNC_CASCHE_PRESSURE, vol);
 		ret = ltfs_write_index(partition, SYNC_CASCHE_PRESSURE, vol);
+	}
 
 	return ret;
 }

src/libltfs/periodic_sync.c

@@ -101,6 +101,7 @@ ltfs_thread_return periodic_sync_thread(void* data)
 			ltfsmsg(LTFS_WARN, 17063W, __FUNCTION__);
 		}
 
+		ltfs_set_commit_message_reason(SYNC_PERIODIC, priv->vol);
 		ret = ltfs_sync_index(SYNC_PERIODIC, true, priv->vol);
 		if (ret < 0) {
 			ltfsmsg(LTFS_INFO, 11030I, ret);

src/libltfs/xattr.c

@@ -881,6 +881,7 @@ static int _xattr_get_virtual(struct dentry *d, char *buf, size_t buf_size, cons
 				ret = _xattr_get_vendorunique_xattr(&val, name, vol);
 			}
 		} else if (! strcmp(name, "ltfs.sync")) {
+			ltfs_set_commit_message_reason(SYNC_EA, vol);
 			ret = ltfs_sync_index(SYNC_EA, false, vol);
 		}
 	}
@@ -915,9 +916,8 @@ static int _xattr_set_virtual(struct dentry *d, const char *name, const char *va
 {
 	int ret = 0;
 
-	if (! strcmp(name, "ltfs.sync") && d == vol->index->root)
-		ret = ltfs_sync_index(SYNC_EA, false, vol);
-	else if (! strcmp(name, "ltfs.commitMessage") && d == vol->index->root) {
+	if ((! strcmp(name, "ltfs.commitMessage") || ! strcmp(name, "ltfs.sync"))
+		&& d == vol->index->root) {
 		char *value_null_terminated, *new_value;
 
 		if (size > INDEX_MAX_COMMENT_LEN) {
@@ -926,38 +926,49 @@ static int _xattr_set_virtual(struct dentry *d, const char *name, const char *va
 		}
 
 		ltfs_mutex_lock(&vol->index->dirty_lock);
-		if (! value || ! size) {
-			/* Clear the current comment field */
-			if (vol->index->commit_message) {
-				free(vol->index->commit_message);
-				vol->index->commit_message = NULL;
-			}
+		if (! vol->index->dirty) {
+			/* Do nothing because index is clean */
+			ret = 0;
 		} else {
-			value_null_terminated = malloc(size + 1);
-			if (! value_null_terminated) {
-				ltfsmsg(LTFS_ERR, 10001E, "_xattr_set_virtual: commit_message");
-				ltfs_mutex_unlock(&vol->index->dirty_lock);
-				return -LTFS_NO_MEMORY;
-			}
-			memcpy(value_null_terminated, value, size);
-			value_null_terminated[size] = '\0';
+			if (! value || ! size) {
+				/* Clear the current comment field */
+				if (vol->index->commit_message) {
+					free(vol->index->commit_message);
+					vol->index->commit_message = NULL;
+				}
+			} else {
+				value_null_terminated = malloc(size + 1);
+				if (! value_null_terminated) {
+					ltfsmsg(LTFS_ERR, 10001E, "_xattr_set_virtual: commit_message");
+					ltfs_mutex_unlock(&vol->index->dirty_lock);
+					return -LTFS_NO_MEMORY;
+				}
+				memcpy(value_null_terminated, value, size);
+				value_null_terminated[size] = '\0';
 
-			ret = pathname_format(value_null_terminated, &new_value, false, true);
-			free(value_null_terminated);
-			if (ret < 0) {
-				ltfs_mutex_unlock(&vol->index->dirty_lock);
-				return ret;
+				ret = pathname_format(value_null_terminated, &new_value, false, true);
+				free(value_null_terminated);
+				if (ret < 0) {
+					/* Try to sync index even if the value is not valid */
+					ltfs_set_commit_message_reason_unlocked(SYNC_EA, vol);
+					ltfs_mutex_unlock(&vol->index->dirty_lock);
+
+					ret = ltfs_sync_index(SYNC_EA, false, vol);
+					return ret;
+				}
+				ret = 0;
+
+				/* Update THE commit message in the index */
+				if (vol->index->commit_message)
+					free(vol->index->commit_message);
+				vol->index->commit_message = new_value;
 			}
-			ret = 0;
 
-			/* Update the commit message in the index */
-			if (vol->index->commit_message)
-				free(vol->index->commit_message);
-			vol->index->commit_message = new_value;
+			ltfs_set_index_dirty(false, false, vol->index);
 		}
 
-		ltfs_set_index_dirty(false, false, vol->index);
 		ltfs_mutex_unlock(&vol->index->dirty_lock);
+		ret = ltfs_sync_index(SYNC_EA, false, vol);
 
 	} else if (! strcmp(name, "ltfs.volumeName") && d == vol->index->root) {
 		char *value_null_terminated, *new_value;
@@ -1228,6 +1239,8 @@ static int _xattr_set_virtual(struct dentry *d, const char *name, const char *va
 			vol->lock_status = new;
 
 			ltfs_set_index_dirty(false, false, vol->index);
+			ltfs_set_commit_message_reason_unlocked(SYNC_ADV_LOCK, vol);
+
 			ret = ltfs_sync_index(SYNC_ADV_LOCK, false, vol);
 			ret = tape_device_lock(vol->device);
 			if (ret < 0) {
@@ -1486,9 +1499,10 @@ int xattr_set(struct dentry *d, const char *name, const char *value, size_t size
 
 	releasewrite_mrsw(&d->meta_lock);
 
-	if (write_idx)
+	if (write_idx) {
+		ltfs_set_commit_message_reason(SYNC_EA, vol);
 		ret = ltfs_sync_index(SYNC_EA, false, vol);
-	else
+	} else
 		ret = 0;
 
 out_unlock:

src/ltfs_fuse.c

@@ -450,8 +450,10 @@ int ltfs_fuse_release(const char *path, struct fuse_file_info *fi)
 
 	open_write = (((fi->flags & O_WRONLY) == O_WRONLY) || ((fi->flags & O_RDWR) == O_RDWR));
 	ret = ltfs_fsops_close(file->file_info->dentry_handle, dirty, open_write, true, priv->data);
-	if (write_index)
+	if (write_index) {
+		ltfs_set_commit_message_reason(SYNC_CLOSE, priv->data);
 		ltfs_sync_index(SYNC_CLOSE, true, priv->data);
+	}
 
 	_file_close(file->file_info, priv);
 	_free_ltfs_file_handle(file);
@@ -1167,6 +1169,7 @@ void ltfs_fuse_umount(void *userdata)
 	if (kmi_initialized(priv->data))
 		kmi_destroy(priv->data);
 
+	ltfs_set_commit_message_reason(SYNC_UNMOUNT, priv->data);
 	ltfs_unmount(SYNC_UNMOUNT, priv->data);
 
 	ltfs_request_trace(FUSE_REQ_EXIT(REQ_UNMOUNT), 0, 0);

src/utils/ltfsck.c

@@ -711,6 +711,7 @@ int check_ltfs_volume(struct ltfs_volume *vol, struct other_check_opts *opt)
 		return LTFSCK_UNCORRECTED;
 	} else {
 		print_criteria_info(vol);
+		ltfs_set_commit_message_reason(SYNC_CHECK, vol);
 		ltfs_unmount(SYNC_CHECK, vol);
 		ltfsmsg(LTFS_INFO, 16022I);
 		return LTFSCK_CORRECTED;
@@ -1174,6 +1175,7 @@ int _rollback_dp(struct ltfs_volume *vol, struct other_check_opts *opt, struct t
 		if (ret != LTFSCK_NO_ERRORS)
 			ltfsmsg(LTFS_ERR, 16055E, ret);
 	} else {
+		ltfs_set_commit_message_reason(SYNC_ROLLBACK, vol);
 		ret = ltfs_write_index(ltfs_dp_id(vol), SYNC_ROLLBACK, vol);
 		if (ret < 0) {
 			ltfsmsg(LTFS_ERR, 16056E, ret);
@@ -1288,6 +1290,7 @@ int rollback(struct ltfs_volume *vol, struct other_check_opts *opt)
 		r.current_pos = ltfs_get_index_selfpointer(vol);
 		ltfsmsg(LTFS_DEBUG, 16081D, ltfs_get_index_generation(vol),
 				(int)r.current_pos.partition, (unsigned long long)r.current_pos.block);
+		ltfs_set_commit_message_reason(SYNC_ROLLBACK, vol);
 		ltfs_unmount(SYNC_ROLLBACK, vol);
 		vol->index = NULL;
 	}