To support reconnecting after restart or crash, VDUSE backend might need to resubmit inflight I/Os. This stores the metadata such as the index of inflight I/O's descriptors to a shm file so that VDUSE backend can restore them during reconnecting.
Signed-off-by: Xie Yongji <xieyon...@bytedance.com> --- block/export/vduse-blk.c | 4 +- subprojects/libvduse/libvduse.c | 254 +++++++++++++++++++++++++++++++- subprojects/libvduse/libvduse.h | 4 +- 3 files changed, 254 insertions(+), 8 deletions(-) diff --git a/block/export/vduse-blk.c b/block/export/vduse-blk.c index 83845e9a9a..bc14fd798b 100644 --- a/block/export/vduse-blk.c +++ b/block/export/vduse-blk.c @@ -232,6 +232,8 @@ static void vduse_blk_enable_queue(VduseDev *dev, VduseVirtq *vq) aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq), true, on_vduse_vq_kick, NULL, NULL, NULL, vq); + /* Make sure we don't miss any kick afer reconnecting */ + eventfd_write(vduse_queue_get_fd(vq), 1); } static void vduse_blk_disable_queue(VduseDev *dev, VduseVirtq *vq) @@ -388,7 +390,7 @@ static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts, features, num_queues, sizeof(struct virtio_blk_config), (char *)&config, &vduse_blk_ops, - vblk_exp); + g_get_tmp_dir(), vblk_exp); if (!vblk_exp->dev) { error_setg(errp, "failed to create vduse device"); return -ENOMEM; diff --git a/subprojects/libvduse/libvduse.c b/subprojects/libvduse/libvduse.c index 7671864bca..ce2f6c7949 100644 --- a/subprojects/libvduse/libvduse.c +++ b/subprojects/libvduse/libvduse.c @@ -41,6 +41,8 @@ #define VDUSE_VQ_ALIGN 4096 #define MAX_IOVA_REGIONS 256 +#define LOG_ALIGNMENT 64 + /* Round number down to multiple */ #define ALIGN_DOWN(n, m) ((n) / (m) * (m)) @@ -51,6 +53,31 @@ #define unlikely(x) __builtin_expect(!!(x), 0) #endif +typedef struct VduseDescStateSplit { + uint8_t inflight; + uint8_t padding[5]; + uint16_t next; + uint64_t counter; +} VduseDescStateSplit; + +typedef struct VduseVirtqLogInflight { + uint64_t features; + uint16_t version; + uint16_t desc_num; + uint16_t last_batch_head; + uint16_t used_idx; + VduseDescStateSplit desc[]; +} VduseVirtqLogInflight; + +typedef struct VduseVirtqLog { + VduseVirtqLogInflight inflight; +} VduseVirtqLog; + +typedef struct VduseVirtqInflightDesc { + uint16_t index; + uint64_t counter; +} VduseVirtqInflightDesc; + typedef struct VduseRing { unsigned int num; uint64_t desc_addr; @@ -73,6 +100,10 @@ struct VduseVirtq { bool ready; int fd; VduseDev *dev; + VduseVirtqInflightDesc *resubmit_list; + uint16_t resubmit_num; + uint64_t counter; + VduseVirtqLog *log; }; typedef struct VduseIovaRegion { @@ -96,8 +127,67 @@ struct VduseDev { int fd; int ctrl_fd; void *priv; + char *shm_log_dir; + void *log; + bool reconnect; }; +static inline size_t vduse_vq_log_size(uint16_t queue_size) +{ + return ALIGN_UP(sizeof(VduseDescStateSplit) * queue_size + + sizeof(VduseVirtqLogInflight), LOG_ALIGNMENT); +} + +static void *vduse_log_get(const char *dir, const char *name, size_t size) +{ + void *ptr = MAP_FAILED; + char *path; + int fd; + + path = (char *)malloc(strlen(dir) + strlen(name) + + strlen("/vduse-log-") + 1); + if (!path) { + return ptr; + } + sprintf(path, "%s/vduse-log-%s", dir, name); + + fd = open(path, O_RDWR | O_CREAT, 0600); + if (fd == -1) { + goto out; + } + + if (ftruncate(fd, size) == -1) { + goto out; + } + + ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if (ptr == MAP_FAILED) { + goto out; + } +out: + if (fd > 0) { + close(fd); + } + free(path); + + return ptr; +} + +static void vduse_log_destroy(const char *dir, const char *name) +{ + char *path; + + path = (char *)malloc(strlen(dir) + strlen(name) + + strlen("/vduse-log-") + 1); + if (!path) { + return; + } + sprintf(path, "%s/vduse-log-%s", dir, name); + + unlink(path); + free(path); +} + static inline bool has_feature(uint64_t features, unsigned int fbit) { assert(fbit < 64); @@ -139,6 +229,98 @@ static int vduse_inject_irq(VduseDev *dev, int index) return ioctl(dev->fd, VDUSE_VQ_INJECT_IRQ, &index); } +static int inflight_desc_compare(const void *a, const void *b) +{ + VduseVirtqInflightDesc *desc0 = (VduseVirtqInflightDesc *)a, + *desc1 = (VduseVirtqInflightDesc *)b; + + if (desc1->counter > desc0->counter && + (desc1->counter - desc0->counter) < VIRTQUEUE_MAX_SIZE * 2) { + return 1; + } + + return -1; +} + +static int vduse_queue_check_inflights(VduseVirtq *vq) +{ + int i = 0; + VduseDev *dev = vq->dev; + + vq->used_idx = vq->vring.used->idx; + vq->resubmit_num = 0; + vq->resubmit_list = NULL; + vq->counter = 0; + + if (unlikely(vq->log->inflight.used_idx != vq->used_idx)) { + vq->log->inflight.desc[vq->log->inflight.last_batch_head].inflight = 0; + + barrier(); + + vq->log->inflight.used_idx = vq->used_idx; + } + + for (i = 0; i < vq->log->inflight.desc_num; i++) { + if (vq->log->inflight.desc[i].inflight == 1) { + vq->inuse++; + } + } + + vq->shadow_avail_idx = vq->last_avail_idx = vq->inuse + vq->used_idx; + + if (vq->inuse) { + vq->resubmit_list = calloc(vq->inuse, sizeof(VduseVirtqInflightDesc)); + if (!vq->resubmit_list) { + return -1; + } + + for (i = 0; i < vq->log->inflight.desc_num; i++) { + if (vq->log->inflight.desc[i].inflight) { + vq->resubmit_list[vq->resubmit_num].index = i; + vq->resubmit_list[vq->resubmit_num].counter = + vq->log->inflight.desc[i].counter; + vq->resubmit_num++; + } + } + + if (vq->resubmit_num > 1) { + qsort(vq->resubmit_list, vq->resubmit_num, + sizeof(VduseVirtqInflightDesc), inflight_desc_compare); + } + vq->counter = vq->resubmit_list[0].counter + 1; + } + + vduse_inject_irq(dev, vq->index); + + return 0; +} + +static int vduse_queue_inflight_get(VduseVirtq *vq, int desc_idx) +{ + vq->log->inflight.desc[desc_idx].counter = vq->counter++; + vq->log->inflight.desc[desc_idx].inflight = 1; + + return 0; +} + +static int vduse_queue_inflight_pre_put(VduseVirtq *vq, int desc_idx) +{ + vq->log->inflight.last_batch_head = desc_idx; + + return 0; +} + +static int vduse_queue_inflight_post_put(VduseVirtq *vq, int desc_idx) +{ + vq->log->inflight.desc[desc_idx].inflight = 0; + + barrier(); + + vq->log->inflight.used_idx = vq->used_idx; + + return 0; +} + static void vduse_iova_remove_region(VduseDev *dev, uint64_t start, uint64_t last) { @@ -578,11 +760,24 @@ void *vduse_queue_pop(VduseVirtq *vq, size_t sz) unsigned int head; VduseVirtqElement *elem; VduseDev *dev = vq->dev; + int i; if (unlikely(!vq->vring.avail)) { return NULL; } + if (unlikely(vq->resubmit_list && vq->resubmit_num > 0)) { + i = (--vq->resubmit_num); + elem = vduse_queue_map_desc(vq, vq->resubmit_list[i].index, sz); + + if (!vq->resubmit_num) { + free(vq->resubmit_list); + vq->resubmit_list = NULL; + } + + return elem; + } + if (vduse_queue_empty(vq)) { return NULL; } @@ -610,6 +805,8 @@ void *vduse_queue_pop(VduseVirtq *vq, size_t sz) vq->inuse++; + vduse_queue_inflight_get(vq, head); + return elem; } @@ -667,7 +864,9 @@ void vduse_queue_push(VduseVirtq *vq, const VduseVirtqElement *elem, unsigned int len) { vduse_queue_fill(vq, elem, len, 0); + vduse_queue_inflight_pre_put(vq, elem->index); vduse_queue_flush(vq, 1); + vduse_queue_inflight_post_put(vq, elem->index); } static int vduse_queue_update_vring(VduseVirtq *vq, uint64_t desc_addr, @@ -740,12 +939,11 @@ static void vduse_queue_enable(VduseVirtq *vq) } vq->fd = fd; - vq->shadow_avail_idx = vq->last_avail_idx = vq_info.split.avail_index; - vq->inuse = 0; - vq->used_idx = 0; vq->signalled_used_valid = false; vq->ready = true; + vduse_queue_check_inflights(vq); + dev->ops->enable_queue(dev, vq); } @@ -903,13 +1101,18 @@ int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size) return -errno; } + if (dev->reconnect) { + vduse_queue_enable(vq); + } + return 0; } VduseDev *vduse_dev_create(const char *name, uint32_t device_id, uint32_t vendor_id, uint64_t features, uint16_t num_queues, uint32_t config_size, - char *config, const VduseOps *ops, void *priv) + char *config, const VduseOps *ops, + const char *shm_log_dir, void *priv) { VduseDev *dev; int i, ret, ctrl_fd, fd = -1; @@ -918,6 +1121,8 @@ VduseDev *vduse_dev_create(const char *name, uint32_t device_id, VduseVirtq *vqs = NULL; struct vduse_dev_config *dev_config = NULL; size_t size = offsetof(struct vduse_dev_config, config); + size_t log_size = num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE); + void *log = NULL; if (!name || strlen(name) > VDUSE_NAME_MAX || !config || !config_size || !ops || !ops->enable_queue || !ops->disable_queue) { @@ -932,6 +1137,15 @@ VduseDev *vduse_dev_create(const char *name, uint32_t device_id, } memset(dev, 0, sizeof(VduseDev)); + if (shm_log_dir) { + dev->log = log = vduse_log_get(shm_log_dir, name, log_size); + if (!log) { + fprintf(stderr, "Failed to get vduse log\n"); + goto err_ctrl; + } + dev->shm_log_dir = strdup(shm_log_dir); + } + ctrl_fd = open("/dev/vduse/control", O_RDWR); if (ctrl_fd < 0) { fprintf(stderr, "Failed to open /dev/vduse/control: %s\n", @@ -964,7 +1178,11 @@ VduseDev *vduse_dev_create(const char *name, uint32_t device_id, ret = ioctl(ctrl_fd, VDUSE_CREATE_DEV, dev_config); free(dev_config); - if (ret < 0) { + if (!ret && log) { + memset(log, 0, log_size); + } else if (errno == EEXIST && log) { + dev->reconnect = true; + } else { fprintf(stderr, "Failed to create vduse dev %s: %s\n", name, strerror(errno)); goto err_dev; @@ -978,6 +1196,12 @@ VduseDev *vduse_dev_create(const char *name, uint32_t device_id, goto err; } + if (dev->reconnect && + ioctl(fd, VDUSE_DEV_GET_FEATURES, &dev->features)) { + fprintf(stderr, "Failed to get features: %s\n", strerror(errno)); + goto err; + } + vqs = calloc(sizeof(VduseVirtq), num_queues); if (!vqs) { fprintf(stderr, "Failed to allocate virtqueues\n"); @@ -988,6 +1212,12 @@ VduseDev *vduse_dev_create(const char *name, uint32_t device_id, vqs[i].index = i; vqs[i].dev = dev; vqs[i].fd = -1; + if (log) { + vqs[i].log = log; + vqs[i].log->inflight.desc_num = VIRTQUEUE_MAX_SIZE; + log = (void *)((char *)log + + vduse_vq_log_size(VIRTQUEUE_MAX_SIZE)); + } } dev->vqs = vqs; @@ -1008,16 +1238,28 @@ err_dev: close(ctrl_fd); err_ctrl: free(dev); + if (log) { + munmap(log, log_size); + } return NULL; } void vduse_dev_destroy(VduseDev *dev) { + size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE); + + if (dev->log) { + munmap(dev->log, log_size); + } free(dev->vqs); close(dev->fd); dev->fd = -1; - ioctl(dev->ctrl_fd, VDUSE_DESTROY_DEV, dev->name); + if (!ioctl(dev->ctrl_fd, VDUSE_DESTROY_DEV, dev->name) && + dev->shm_log_dir) { + vduse_log_destroy(dev->shm_log_dir, dev->name); + } + free(dev->shm_log_dir); free(dev->name); close(dev->ctrl_fd); dev->ctrl_fd = -1; diff --git a/subprojects/libvduse/libvduse.h b/subprojects/libvduse/libvduse.h index f6bcb51b5a..a46e71e0c2 100644 --- a/subprojects/libvduse/libvduse.h +++ b/subprojects/libvduse/libvduse.h @@ -171,6 +171,7 @@ int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size); * @config_size: the size of the configuration space * @config: the buffer of the configuration space * @ops: the operation of VDUSE backend + * @shm_log_dir: directory to store the metadata file for reconnect * @priv: private pointer * * Create VDUSE device. @@ -180,7 +181,8 @@ int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size); VduseDev *vduse_dev_create(const char *name, uint32_t device_id, uint32_t vendor_id, uint64_t features, uint16_t num_queues, uint32_t config_size, - char *config, const VduseOps *ops, void *priv); + char *config, const VduseOps *ops, + const char *shm_log_dir, void *priv); /** * vduse_dev_destroy: -- 2.20.1