diff options
Diffstat (limited to 'scsi/pr-manager-helper.c')
| -rw-r--r-- | scsi/pr-manager-helper.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/scsi/pr-manager-helper.c b/scsi/pr-manager-helper.c new file mode 100644 index 0000000000..82ff6b6123 --- /dev/null +++ b/scsi/pr-manager-helper.c @@ -0,0 +1,302 @@ +/* + * Persistent reservation manager that talks to qemu-pr-helper + * + * Copyright (c) 2017 Red Hat, Inc. + * + * Author: Paolo Bonzini <pbonzini@redhat.com> + * + * This code is licensed under the LGPL v2.1 or later. + * + */ + +#include "qemu/osdep.h" +#include "qapi/error.h" +#include "scsi/constants.h" +#include "scsi/pr-manager.h" +#include "scsi/utils.h" +#include "io/channel.h" +#include "io/channel-socket.h" +#include "pr-helper.h" + +#include <scsi/sg.h> + +#define PR_MAX_RECONNECT_ATTEMPTS 5 + +#define TYPE_PR_MANAGER_HELPER "pr-manager-helper" + +#define PR_MANAGER_HELPER(obj) \ + OBJECT_CHECK(PRManagerHelper, (obj), \ + TYPE_PR_MANAGER_HELPER) + +typedef struct PRManagerHelper { + /* <private> */ + PRManager parent; + + char *path; + + QemuMutex lock; + QIOChannel *ioc; +} PRManagerHelper; + +/* Called with lock held. */ +static int pr_manager_helper_read(PRManagerHelper *pr_mgr, + void *buf, int sz, Error **errp) +{ + ssize_t r = qio_channel_read_all(pr_mgr->ioc, buf, sz, errp); + + if (r < 0) { + object_unref(OBJECT(pr_mgr->ioc)); + pr_mgr->ioc = NULL; + return -EINVAL; + } + + return 0; +} + +/* Called with lock held. */ +static int pr_manager_helper_write(PRManagerHelper *pr_mgr, + int fd, + const void *buf, int sz, Error **errp) +{ + size_t nfds = (fd != -1); + while (sz > 0) { + struct iovec iov; + ssize_t n_written; + + iov.iov_base = (void *)buf; + iov.iov_len = sz; + n_written = qio_channel_writev_full(QIO_CHANNEL(pr_mgr->ioc), &iov, 1, + nfds ? &fd : NULL, nfds, errp); + + if (n_written <= 0) { + assert(n_written != QIO_CHANNEL_ERR_BLOCK); + object_unref(OBJECT(pr_mgr->ioc)); + return n_written < 0 ? -EINVAL : 0; + } + + nfds = 0; + buf += n_written; + sz -= n_written; + } + + return 0; +} + +/* Called with lock held. */ +static int pr_manager_helper_initialize(PRManagerHelper *pr_mgr, + Error **errp) +{ + char *path = g_strdup(pr_mgr->path); + SocketAddress saddr = { + .type = SOCKET_ADDRESS_TYPE_UNIX, + .u.q_unix.path = path + }; + QIOChannelSocket *sioc = qio_channel_socket_new(); + Error *local_err = NULL; + + uint32_t flags; + int r; + + assert(!pr_mgr->ioc); + qio_channel_set_name(QIO_CHANNEL(sioc), "pr-manager-helper"); + qio_channel_socket_connect_sync(sioc, + &saddr, + &local_err); + g_free(path); + if (local_err) { + object_unref(OBJECT(sioc)); + error_propagate(errp, local_err); + return -ENOTCONN; + } + + qio_channel_set_delay(QIO_CHANNEL(sioc), false); + pr_mgr->ioc = QIO_CHANNEL(sioc); + + /* A simple feature negotation protocol, even though there is + * no optional feature right now. + */ + r = pr_manager_helper_read(pr_mgr, &flags, sizeof(flags), errp); + if (r < 0) { + goto out_close; + } + + flags = 0; + r = pr_manager_helper_write(pr_mgr, -1, &flags, sizeof(flags), errp); + if (r < 0) { + goto out_close; + } + + return 0; + +out_close: + object_unref(OBJECT(pr_mgr->ioc)); + pr_mgr->ioc = NULL; + return r; +} + +static int pr_manager_helper_run(PRManager *p, + int fd, struct sg_io_hdr *io_hdr) +{ + PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(p); + + uint32_t len; + PRHelperResponse resp; + int ret; + int expected_dir; + int attempts; + uint8_t cdb[PR_HELPER_CDB_SIZE] = { 0 }; + + if (!io_hdr->cmd_len || io_hdr->cmd_len > PR_HELPER_CDB_SIZE) { + return -EINVAL; + } + + memcpy(cdb, io_hdr->cmdp, io_hdr->cmd_len); + assert(cdb[0] == PERSISTENT_RESERVE_OUT || cdb[0] == PERSISTENT_RESERVE_IN); + expected_dir = + (cdb[0] == PERSISTENT_RESERVE_OUT ? SG_DXFER_TO_DEV : SG_DXFER_FROM_DEV); + if (io_hdr->dxfer_direction != expected_dir) { + return -EINVAL; + } + + len = scsi_cdb_xfer(cdb); + if (io_hdr->dxfer_len < len || len > PR_HELPER_DATA_SIZE) { + return -EINVAL; + } + + qemu_mutex_lock(&pr_mgr->lock); + + /* Try to reconnect while sending the CDB. */ + for (attempts = 0; attempts < PR_MAX_RECONNECT_ATTEMPTS; attempts++) { + if (!pr_mgr->ioc) { + ret = pr_manager_helper_initialize(pr_mgr, NULL); + if (ret < 0) { + qemu_mutex_unlock(&pr_mgr->lock); + g_usleep(G_USEC_PER_SEC); + qemu_mutex_lock(&pr_mgr->lock); + continue; + } + } + + ret = pr_manager_helper_write(pr_mgr, fd, cdb, ARRAY_SIZE(cdb), NULL); + if (ret >= 0) { + break; + } + } + if (ret < 0) { + goto out; + } + + /* After sending the CDB, any communications failure causes the + * command to fail. The failure is transient, retrying the command + * will invoke pr_manager_helper_initialize again. + */ + if (expected_dir == SG_DXFER_TO_DEV) { + io_hdr->resid = io_hdr->dxfer_len - len; + ret = pr_manager_helper_write(pr_mgr, -1, io_hdr->dxferp, len, NULL); + if (ret < 0) { + goto out; + } + } + ret = pr_manager_helper_read(pr_mgr, &resp, sizeof(resp), NULL); + if (ret < 0) { + goto out; + } + + resp.result = be32_to_cpu(resp.result); + resp.sz = be32_to_cpu(resp.sz); + if (io_hdr->dxfer_direction == SG_DXFER_FROM_DEV) { + assert(resp.sz <= io_hdr->dxfer_len); + ret = pr_manager_helper_read(pr_mgr, io_hdr->dxferp, resp.sz, NULL); + if (ret < 0) { + goto out; + } + io_hdr->resid = io_hdr->dxfer_len - resp.sz; + } else { + assert(resp.sz == 0); + } + + io_hdr->status = resp.result; + if (resp.result == CHECK_CONDITION) { + io_hdr->driver_status = SG_ERR_DRIVER_SENSE; + io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, PR_HELPER_SENSE_SIZE); + memcpy(io_hdr->sbp, resp.sense, io_hdr->sb_len_wr); + } + +out: + if (ret < 0) { + int sense_len = scsi_build_sense(io_hdr->sbp, + SENSE_CODE(LUN_COMM_FAILURE)); + io_hdr->driver_status = SG_ERR_DRIVER_SENSE; + io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, sense_len); + io_hdr->status = CHECK_CONDITION; + } + qemu_mutex_unlock(&pr_mgr->lock); + return ret; +} + +static void pr_manager_helper_complete(UserCreatable *uc, Error **errp) +{ + PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(uc); + + qemu_mutex_lock(&pr_mgr->lock); + pr_manager_helper_initialize(pr_mgr, errp); + qemu_mutex_unlock(&pr_mgr->lock); +} + +static char *get_path(Object *obj, Error **errp) +{ + PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj); + + return g_strdup(pr_mgr->path); +} + +static void set_path(Object *obj, const char *str, Error **errp) +{ + PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj); + + g_free(pr_mgr->path); + pr_mgr->path = g_strdup(str); +} + +static void pr_manager_helper_instance_finalize(Object *obj) +{ + PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj); + + object_unref(OBJECT(pr_mgr->ioc)); + qemu_mutex_destroy(&pr_mgr->lock); +} + +static void pr_manager_helper_instance_init(Object *obj) +{ + PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj); + + qemu_mutex_init(&pr_mgr->lock); +} + +static void pr_manager_helper_class_init(ObjectClass *klass, + void *class_data G_GNUC_UNUSED) +{ + PRManagerClass *prmgr_klass = PR_MANAGER_CLASS(klass); + UserCreatableClass *uc_klass = USER_CREATABLE_CLASS(klass); + + object_class_property_add_str(klass, "path", get_path, set_path, + &error_abort); + uc_klass->complete = pr_manager_helper_complete; + prmgr_klass->run = pr_manager_helper_run; +} + +static const TypeInfo pr_manager_helper_info = { + .parent = TYPE_PR_MANAGER, + .name = TYPE_PR_MANAGER_HELPER, + .instance_size = sizeof(PRManagerHelper), + .instance_init = pr_manager_helper_instance_init, + .instance_finalize = pr_manager_helper_instance_finalize, + .class_init = pr_manager_helper_class_init, +}; + +static void pr_manager_helper_register_types(void) +{ + type_register_static(&pr_manager_helper_info); +} + +type_init(pr_manager_helper_register_types); |