| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * virtio-fs: Virtio Filesystem |
| * Copyright (C) 2018 Red Hat, Inc. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/dax.h> |
| #include <linux/pci.h> |
| #include <linux/pfn_t.h> |
| #include <linux/module.h> |
| #include <linux/virtio.h> |
| #include <linux/virtio_fs.h> |
| #include <linux/delay.h> |
| #include <linux/fs_context.h> |
| #include <linux/fs_parser.h> |
| #include <linux/highmem.h> |
| #include <linux/uio.h> |
| #include "fuse_i.h" |
| |
| /* Used to help calculate the FUSE connection's max_pages limit for a request's |
| * size. Parts of the struct fuse_req are sliced into scattergather lists in |
| * addition to the pages used, so this can help account for that overhead. |
| */ |
| #define FUSE_HEADER_OVERHEAD 4 |
| |
| /* List of virtio-fs device instances and a lock for the list. Also provides |
| * mutual exclusion in device removal and mounting path |
| */ |
| static DEFINE_MUTEX(virtio_fs_mutex); |
| static LIST_HEAD(virtio_fs_instances); |
| |
| enum { |
| VQ_HIPRIO, |
| VQ_REQUEST |
| }; |
| |
| #define VQ_NAME_LEN 24 |
| |
| /* Per-virtqueue state */ |
| struct virtio_fs_vq { |
| spinlock_t lock; |
| struct virtqueue *vq; /* protected by ->lock */ |
| struct work_struct done_work; |
| struct list_head queued_reqs; |
| struct list_head end_reqs; /* End these requests */ |
| struct delayed_work dispatch_work; |
| struct fuse_dev *fud; |
| bool connected; |
| long in_flight; |
| struct completion in_flight_zero; /* No inflight requests */ |
| char name[VQ_NAME_LEN]; |
| } ____cacheline_aligned_in_smp; |
| |
| /* A virtio-fs device instance */ |
| struct virtio_fs { |
| struct kref refcount; |
| struct list_head list; /* on virtio_fs_instances */ |
| char *tag; |
| struct virtio_fs_vq *vqs; |
| unsigned int nvqs; /* number of virtqueues */ |
| unsigned int num_request_queues; /* number of request queues */ |
| struct dax_device *dax_dev; |
| |
| /* DAX memory window where file contents are mapped */ |
| void *window_kaddr; |
| phys_addr_t window_phys_addr; |
| size_t window_len; |
| }; |
| |
| struct virtio_fs_forget_req { |
| struct fuse_in_header ih; |
| struct fuse_forget_in arg; |
| }; |
| |
| struct virtio_fs_forget { |
| /* This request can be temporarily queued on virt queue */ |
| struct list_head list; |
| struct virtio_fs_forget_req req; |
| }; |
| |
| struct virtio_fs_req_work { |
| struct fuse_req *req; |
| struct virtio_fs_vq *fsvq; |
| struct work_struct done_work; |
| }; |
| |
| static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, |
| struct fuse_req *req, bool in_flight); |
| |
| enum { |
| OPT_DAX, |
| }; |
| |
| static const struct fs_parameter_spec virtio_fs_parameters[] = { |
| fsparam_flag("dax", OPT_DAX), |
| {} |
| }; |
| |
| static int virtio_fs_parse_param(struct fs_context *fc, |
| struct fs_parameter *param) |
| { |
| struct fs_parse_result result; |
| struct fuse_fs_context *ctx = fc->fs_private; |
| int opt; |
| |
| opt = fs_parse(fc, virtio_fs_parameters, param, &result); |
| if (opt < 0) |
| return opt; |
| |
| switch (opt) { |
| case OPT_DAX: |
| ctx->dax = 1; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| static void virtio_fs_free_fc(struct fs_context *fc) |
| { |
| struct fuse_fs_context *ctx = fc->fs_private; |
| |
| kfree(ctx); |
| } |
| |
| static inline struct virtio_fs_vq *vq_to_fsvq(struct virtqueue *vq) |
| { |
| struct virtio_fs *fs = vq->vdev->priv; |
| |
| return &fs->vqs[vq->index]; |
| } |
| |
| /* Should be called with fsvq->lock held. */ |
| static inline void inc_in_flight_req(struct virtio_fs_vq *fsvq) |
| { |
| fsvq->in_flight++; |
| } |
| |
| /* Should be called with fsvq->lock held. */ |
| static inline void dec_in_flight_req(struct virtio_fs_vq *fsvq) |
| { |
| WARN_ON(fsvq->in_flight <= 0); |
| fsvq->in_flight--; |
| if (!fsvq->in_flight) |
| complete(&fsvq->in_flight_zero); |
| } |
| |
| static void release_virtio_fs_obj(struct kref *ref) |
| { |
| struct virtio_fs *vfs = container_of(ref, struct virtio_fs, refcount); |
| |
| kfree(vfs->vqs); |
| kfree(vfs); |
| } |
| |
| /* Make sure virtiofs_mutex is held */ |
| static void virtio_fs_put(struct virtio_fs *fs) |
| { |
| kref_put(&fs->refcount, release_virtio_fs_obj); |
| } |
| |
| static void virtio_fs_fiq_release(struct fuse_iqueue *fiq) |
| { |
| struct virtio_fs *vfs = fiq->priv; |
| |
| mutex_lock(&virtio_fs_mutex); |
| virtio_fs_put(vfs); |
| mutex_unlock(&virtio_fs_mutex); |
| } |
| |
| static void virtio_fs_drain_queue(struct virtio_fs_vq *fsvq) |
| { |
| WARN_ON(fsvq->in_flight < 0); |
| |
| /* Wait for in flight requests to finish.*/ |
| spin_lock(&fsvq->lock); |
| if (fsvq->in_flight) { |
| /* We are holding virtio_fs_mutex. There should not be any |
| * waiters waiting for completion. |
| */ |
| reinit_completion(&fsvq->in_flight_zero); |
| spin_unlock(&fsvq->lock); |
| wait_for_completion(&fsvq->in_flight_zero); |
| } else { |
| spin_unlock(&fsvq->lock); |
| } |
| |
| flush_work(&fsvq->done_work); |
| flush_delayed_work(&fsvq->dispatch_work); |
| } |
| |
| static void virtio_fs_drain_all_queues_locked(struct virtio_fs *fs) |
| { |
| struct virtio_fs_vq *fsvq; |
| int i; |
| |
| for (i = 0; i < fs->nvqs; i++) { |
| fsvq = &fs->vqs[i]; |
| virtio_fs_drain_queue(fsvq); |
| } |
| } |
| |
| static void virtio_fs_drain_all_queues(struct virtio_fs *fs) |
| { |
| /* Provides mutual exclusion between ->remove and ->kill_sb |
| * paths. We don't want both of these draining queue at the |
| * same time. Current completion logic reinits completion |
| * and that means there should not be any other thread |
| * doing reinit or waiting for completion already. |
| */ |
| mutex_lock(&virtio_fs_mutex); |
| virtio_fs_drain_all_queues_locked(fs); |
| mutex_unlock(&virtio_fs_mutex); |
| } |
| |
| static void virtio_fs_start_all_queues(struct virtio_fs *fs) |
| { |
| struct virtio_fs_vq *fsvq; |
| int i; |
| |
| for (i = 0; i < fs->nvqs; i++) { |
| fsvq = &fs->vqs[i]; |
| spin_lock(&fsvq->lock); |
| fsvq->connected = true; |
| spin_unlock(&fsvq->lock); |
| } |
| } |
| |
| /* Add a new instance to the list or return -EEXIST if tag name exists*/ |
| static int virtio_fs_add_instance(struct virtio_fs *fs) |
| { |
| struct virtio_fs *fs2; |
| bool duplicate = false; |
| |
| mutex_lock(&virtio_fs_mutex); |
| |
| list_for_each_entry(fs2, &virtio_fs_instances, list) { |
| if (strcmp(fs->tag, fs2->tag) == 0) |
| duplicate = true; |
| } |
| |
| if (!duplicate) |
| list_add_tail(&fs->list, &virtio_fs_instances); |
| |
| mutex_unlock(&virtio_fs_mutex); |
| |
| if (duplicate) |
| return -EEXIST; |
| return 0; |
| } |
| |
| /* Return the virtio_fs with a given tag, or NULL */ |
| static struct virtio_fs *virtio_fs_find_instance(const char *tag) |
| { |
| struct virtio_fs *fs; |
| |
| mutex_lock(&virtio_fs_mutex); |
| |
| list_for_each_entry(fs, &virtio_fs_instances, list) { |
| if (strcmp(fs->tag, tag) == 0) { |
| kref_get(&fs->refcount); |
| goto found; |
| } |
| } |
| |
| fs = NULL; /* not found */ |
| |
| found: |
| mutex_unlock(&virtio_fs_mutex); |
| |
| return fs; |
| } |
| |
| static void virtio_fs_free_devs(struct virtio_fs *fs) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < fs->nvqs; i++) { |
| struct virtio_fs_vq *fsvq = &fs->vqs[i]; |
| |
| if (!fsvq->fud) |
| continue; |
| |
| fuse_dev_free(fsvq->fud); |
| fsvq->fud = NULL; |
| } |
| } |
| |
| /* Read filesystem name from virtio config into fs->tag (must kfree()). */ |
| static int virtio_fs_read_tag(struct virtio_device *vdev, struct virtio_fs *fs) |
| { |
| char tag_buf[sizeof_field(struct virtio_fs_config, tag)]; |
| char *end; |
| size_t len; |
| |
| virtio_cread_bytes(vdev, offsetof(struct virtio_fs_config, tag), |
| &tag_buf, sizeof(tag_buf)); |
| end = memchr(tag_buf, '\0', sizeof(tag_buf)); |
| if (end == tag_buf) |
| return -EINVAL; /* empty tag */ |
| if (!end) |
| end = &tag_buf[sizeof(tag_buf)]; |
| |
| len = end - tag_buf; |
| fs->tag = devm_kmalloc(&vdev->dev, len + 1, GFP_KERNEL); |
| if (!fs->tag) |
| return -ENOMEM; |
| memcpy(fs->tag, tag_buf, len); |
| fs->tag[len] = '\0'; |
| return 0; |
| } |
| |
| /* Work function for hiprio completion */ |
| static void virtio_fs_hiprio_done_work(struct work_struct *work) |
| { |
| struct virtio_fs_vq *fsvq = container_of(work, struct virtio_fs_vq, |
| done_work); |
| struct virtqueue *vq = fsvq->vq; |
| |
| /* Free completed FUSE_FORGET requests */ |
| spin_lock(&fsvq->lock); |
| do { |
| unsigned int len; |
| void *req; |
| |
| virtqueue_disable_cb(vq); |
| |
| while ((req = virtqueue_get_buf(vq, &len)) != NULL) { |
| kfree(req); |
| dec_in_flight_req(fsvq); |
| } |
| } while (!virtqueue_enable_cb(vq) && likely(!virtqueue_is_broken(vq))); |
| spin_unlock(&fsvq->lock); |
| } |
| |
| static void virtio_fs_request_dispatch_work(struct work_struct *work) |
| { |
| struct fuse_req *req; |
| struct virtio_fs_vq *fsvq = container_of(work, struct virtio_fs_vq, |
| dispatch_work.work); |
| int ret; |
| |
| pr_debug("virtio-fs: worker %s called.\n", __func__); |
| while (1) { |
| spin_lock(&fsvq->lock); |
| req = list_first_entry_or_null(&fsvq->end_reqs, struct fuse_req, |
| list); |
| if (!req) { |
| spin_unlock(&fsvq->lock); |
| break; |
| } |
| |
| list_del_init(&req->list); |
| spin_unlock(&fsvq->lock); |
| fuse_request_end(req); |
| } |
| |
| /* Dispatch pending requests */ |
| while (1) { |
| spin_lock(&fsvq->lock); |
| req = list_first_entry_or_null(&fsvq->queued_reqs, |
| struct fuse_req, list); |
| if (!req) { |
| spin_unlock(&fsvq->lock); |
| return; |
| } |
| list_del_init(&req->list); |
| spin_unlock(&fsvq->lock); |
| |
| ret = virtio_fs_enqueue_req(fsvq, req, true); |
| if (ret < 0) { |
| if (ret == -ENOMEM || ret == -ENOSPC) { |
| spin_lock(&fsvq->lock); |
| list_add_tail(&req->list, &fsvq->queued_reqs); |
| schedule_delayed_work(&fsvq->dispatch_work, |
| msecs_to_jiffies(1)); |
| spin_unlock(&fsvq->lock); |
| return; |
| } |
| req->out.h.error = ret; |
| spin_lock(&fsvq->lock); |
| dec_in_flight_req(fsvq); |
| spin_unlock(&fsvq->lock); |
| pr_err("virtio-fs: virtio_fs_enqueue_req() failed %d\n", |
| ret); |
| fuse_request_end(req); |
| } |
| } |
| } |
| |
| /* |
| * Returns 1 if queue is full and sender should wait a bit before sending |
| * next request, 0 otherwise. |
| */ |
| static int send_forget_request(struct virtio_fs_vq *fsvq, |
| struct virtio_fs_forget *forget, |
| bool in_flight) |
| { |
| struct scatterlist sg; |
| struct virtqueue *vq; |
| int ret = 0; |
| bool notify; |
| struct virtio_fs_forget_req *req = &forget->req; |
| |
| spin_lock(&fsvq->lock); |
| if (!fsvq->connected) { |
| if (in_flight) |
| dec_in_flight_req(fsvq); |
| kfree(forget); |
| goto out; |
| } |
| |
| sg_init_one(&sg, req, sizeof(*req)); |
| vq = fsvq->vq; |
| dev_dbg(&vq->vdev->dev, "%s\n", __func__); |
| |
| ret = virtqueue_add_outbuf(vq, &sg, 1, forget, GFP_ATOMIC); |
| if (ret < 0) { |
| if (ret == -ENOMEM || ret == -ENOSPC) { |
| pr_debug("virtio-fs: Could not queue FORGET: err=%d. Will try later\n", |
| ret); |
| list_add_tail(&forget->list, &fsvq->queued_reqs); |
| schedule_delayed_work(&fsvq->dispatch_work, |
| msecs_to_jiffies(1)); |
| if (!in_flight) |
| inc_in_flight_req(fsvq); |
| /* Queue is full */ |
| ret = 1; |
| } else { |
| pr_debug("virtio-fs: Could not queue FORGET: err=%d. Dropping it.\n", |
| ret); |
| kfree(forget); |
| if (in_flight) |
| dec_in_flight_req(fsvq); |
| } |
| goto out; |
| } |
| |
| if (!in_flight) |
| inc_in_flight_req(fsvq); |
| notify = virtqueue_kick_prepare(vq); |
| spin_unlock(&fsvq->lock); |
| |
| if (notify) |
| virtqueue_notify(vq); |
| return ret; |
| out: |
| spin_unlock(&fsvq->lock); |
| return ret; |
| } |
| |
| static void virtio_fs_hiprio_dispatch_work(struct work_struct *work) |
| { |
| struct virtio_fs_forget *forget; |
| struct virtio_fs_vq *fsvq = container_of(work, struct virtio_fs_vq, |
| dispatch_work.work); |
| pr_debug("virtio-fs: worker %s called.\n", __func__); |
| while (1) { |
| spin_lock(&fsvq->lock); |
| forget = list_first_entry_or_null(&fsvq->queued_reqs, |
| struct virtio_fs_forget, list); |
| if (!forget) { |
| spin_unlock(&fsvq->lock); |
| return; |
| } |
| |
| list_del(&forget->list); |
| spin_unlock(&fsvq->lock); |
| if (send_forget_request(fsvq, forget, true)) |
| return; |
| } |
| } |
| |
| /* Allocate and copy args into req->argbuf */ |
| static int copy_args_to_argbuf(struct fuse_req *req) |
| { |
| struct fuse_args *args = req->args; |
| unsigned int offset = 0; |
| unsigned int num_in; |
| unsigned int num_out; |
| unsigned int len; |
| unsigned int i; |
| |
| num_in = args->in_numargs - args->in_pages; |
| num_out = args->out_numargs - args->out_pages; |
| len = fuse_len_args(num_in, (struct fuse_arg *) args->in_args) + |
| fuse_len_args(num_out, args->out_args); |
| |
| req->argbuf = kmalloc(len, GFP_ATOMIC); |
| if (!req->argbuf) |
| return -ENOMEM; |
| |
| for (i = 0; i < num_in; i++) { |
| memcpy(req->argbuf + offset, |
| args->in_args[i].value, |
| args->in_args[i].size); |
| offset += args->in_args[i].size; |
| } |
| |
| return 0; |
| } |
| |
| /* Copy args out of and free req->argbuf */ |
| static void copy_args_from_argbuf(struct fuse_args *args, struct fuse_req *req) |
| { |
| unsigned int remaining; |
| unsigned int offset; |
| unsigned int num_in; |
| unsigned int num_out; |
| unsigned int i; |
| |
| remaining = req->out.h.len - sizeof(req->out.h); |
| num_in = args->in_numargs - args->in_pages; |
| num_out = args->out_numargs - args->out_pages; |
| offset = fuse_len_args(num_in, (struct fuse_arg *)args->in_args); |
| |
| for (i = 0; i < num_out; i++) { |
| unsigned int argsize = args->out_args[i].size; |
| |
| if (args->out_argvar && |
| i == args->out_numargs - 1 && |
| argsize > remaining) { |
| argsize = remaining; |
| } |
| |
| memcpy(args->out_args[i].value, req->argbuf + offset, argsize); |
| offset += argsize; |
| |
| if (i != args->out_numargs - 1) |
| remaining -= argsize; |
| } |
| |
| /* Store the actual size of the variable-length arg */ |
| if (args->out_argvar) |
| args->out_args[args->out_numargs - 1].size = remaining; |
| |
| kfree(req->argbuf); |
| req->argbuf = NULL; |
| } |
| |
| /* Work function for request completion */ |
| static void virtio_fs_request_complete(struct fuse_req *req, |
| struct virtio_fs_vq *fsvq) |
| { |
| struct fuse_pqueue *fpq = &fsvq->fud->pq; |
| struct fuse_args *args; |
| struct fuse_args_pages *ap; |
| unsigned int len, i, thislen; |
| struct page *page; |
| |
| /* |
| * TODO verify that server properly follows FUSE protocol |
| * (oh.uniq, oh.len) |
| */ |
| args = req->args; |
| copy_args_from_argbuf(args, req); |
| |
| if (args->out_pages && args->page_zeroing) { |
| len = args->out_args[args->out_numargs - 1].size; |
| ap = container_of(args, typeof(*ap), args); |
| for (i = 0; i < ap->num_pages; i++) { |
| thislen = ap->descs[i].length; |
| if (len < thislen) { |
| WARN_ON(ap->descs[i].offset); |
| page = ap->pages[i]; |
| zero_user_segment(page, len, thislen); |
| len = 0; |
| } else { |
| len -= thislen; |
| } |
| } |
| } |
| |
| spin_lock(&fpq->lock); |
| clear_bit(FR_SENT, &req->flags); |
| spin_unlock(&fpq->lock); |
| |
| fuse_request_end(req); |
| spin_lock(&fsvq->lock); |
| dec_in_flight_req(fsvq); |
| spin_unlock(&fsvq->lock); |
| } |
| |
| static void virtio_fs_complete_req_work(struct work_struct *work) |
| { |
| struct virtio_fs_req_work *w = |
| container_of(work, typeof(*w), done_work); |
| |
| virtio_fs_request_complete(w->req, w->fsvq); |
| kfree(w); |
| } |
| |
| static void virtio_fs_requests_done_work(struct work_struct *work) |
| { |
| struct virtio_fs_vq *fsvq = container_of(work, struct virtio_fs_vq, |
| done_work); |
| struct fuse_pqueue *fpq = &fsvq->fud->pq; |
| struct virtqueue *vq = fsvq->vq; |
| struct fuse_req *req; |
| struct fuse_req *next; |
| unsigned int len; |
| LIST_HEAD(reqs); |
| |
| /* Collect completed requests off the virtqueue */ |
| spin_lock(&fsvq->lock); |
| do { |
| virtqueue_disable_cb(vq); |
| |
| while ((req = virtqueue_get_buf(vq, &len)) != NULL) { |
| spin_lock(&fpq->lock); |
| list_move_tail(&req->list, &reqs); |
| spin_unlock(&fpq->lock); |
| } |
| } while (!virtqueue_enable_cb(vq) && likely(!virtqueue_is_broken(vq))); |
| spin_unlock(&fsvq->lock); |
| |
| /* End requests */ |
| list_for_each_entry_safe(req, next, &reqs, list) { |
| list_del_init(&req->list); |
| |
| /* blocking async request completes in a worker context */ |
| if (req->args->may_block) { |
| struct virtio_fs_req_work *w; |
| |
| w = kzalloc(sizeof(*w), GFP_NOFS | __GFP_NOFAIL); |
| INIT_WORK(&w->done_work, virtio_fs_complete_req_work); |
| w->fsvq = fsvq; |
| w->req = req; |
| schedule_work(&w->done_work); |
| } else { |
| virtio_fs_request_complete(req, fsvq); |
| } |
| } |
| } |
| |
| /* Virtqueue interrupt handler */ |
| static void virtio_fs_vq_done(struct virtqueue *vq) |
| { |
| struct virtio_fs_vq *fsvq = vq_to_fsvq(vq); |
| |
| dev_dbg(&vq->vdev->dev, "%s %s\n", __func__, fsvq->name); |
| |
| schedule_work(&fsvq->done_work); |
| } |
| |
| static void virtio_fs_init_vq(struct virtio_fs_vq *fsvq, char *name, |
| int vq_type) |
| { |
| strncpy(fsvq->name, name, VQ_NAME_LEN); |
| spin_lock_init(&fsvq->lock); |
| INIT_LIST_HEAD(&fsvq->queued_reqs); |
| INIT_LIST_HEAD(&fsvq->end_reqs); |
| init_completion(&fsvq->in_flight_zero); |
| |
| if (vq_type == VQ_REQUEST) { |
| INIT_WORK(&fsvq->done_work, virtio_fs_requests_done_work); |
| INIT_DELAYED_WORK(&fsvq->dispatch_work, |
| virtio_fs_request_dispatch_work); |
| } else { |
| INIT_WORK(&fsvq->done_work, virtio_fs_hiprio_done_work); |
| INIT_DELAYED_WORK(&fsvq->dispatch_work, |
| virtio_fs_hiprio_dispatch_work); |
| } |
| } |
| |
| /* Initialize virtqueues */ |
| static int virtio_fs_setup_vqs(struct virtio_device *vdev, |
| struct virtio_fs *fs) |
| { |
| struct virtqueue **vqs; |
| vq_callback_t **callbacks; |
| const char **names; |
| unsigned int i; |
| int ret = 0; |
| |
| virtio_cread_le(vdev, struct virtio_fs_config, num_request_queues, |
| &fs->num_request_queues); |
| if (fs->num_request_queues == 0) |
| return -EINVAL; |
| |
| fs->nvqs = VQ_REQUEST + fs->num_request_queues; |
| fs->vqs = kcalloc(fs->nvqs, sizeof(fs->vqs[VQ_HIPRIO]), GFP_KERNEL); |
| if (!fs->vqs) |
| return -ENOMEM; |
| |
| vqs = kmalloc_array(fs->nvqs, sizeof(vqs[VQ_HIPRIO]), GFP_KERNEL); |
| callbacks = kmalloc_array(fs->nvqs, sizeof(callbacks[VQ_HIPRIO]), |
| GFP_KERNEL); |
| names = kmalloc_array(fs->nvqs, sizeof(names[VQ_HIPRIO]), GFP_KERNEL); |
| if (!vqs || !callbacks || !names) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| /* Initialize the hiprio/forget request virtqueue */ |
| callbacks[VQ_HIPRIO] = virtio_fs_vq_done; |
| virtio_fs_init_vq(&fs->vqs[VQ_HIPRIO], "hiprio", VQ_HIPRIO); |
| names[VQ_HIPRIO] = fs->vqs[VQ_HIPRIO].name; |
| |
| /* Initialize the requests virtqueues */ |
| for (i = VQ_REQUEST; i < fs->nvqs; i++) { |
| char vq_name[VQ_NAME_LEN]; |
| |
| snprintf(vq_name, VQ_NAME_LEN, "requests.%u", i - VQ_REQUEST); |
| virtio_fs_init_vq(&fs->vqs[i], vq_name, VQ_REQUEST); |
| callbacks[i] = virtio_fs_vq_done; |
| names[i] = fs->vqs[i].name; |
| } |
| |
| ret = virtio_find_vqs(vdev, fs->nvqs, vqs, callbacks, names, NULL); |
| if (ret < 0) |
| goto out; |
| |
| for (i = 0; i < fs->nvqs; i++) |
| fs->vqs[i].vq = vqs[i]; |
| |
| virtio_fs_start_all_queues(fs); |
| out: |
| kfree(names); |
| kfree(callbacks); |
| kfree(vqs); |
| if (ret) |
| kfree(fs->vqs); |
| return ret; |
| } |
| |
| /* Free virtqueues (device must already be reset) */ |
| static void virtio_fs_cleanup_vqs(struct virtio_device *vdev, |
| struct virtio_fs *fs) |
| { |
| vdev->config->del_vqs(vdev); |
| } |
| |
| /* Map a window offset to a page frame number. The window offset will have |
| * been produced by .iomap_begin(), which maps a file offset to a window |
| * offset. |
| */ |
| static long virtio_fs_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, |
| long nr_pages, void **kaddr, pfn_t *pfn) |
| { |
| struct virtio_fs *fs = dax_get_private(dax_dev); |
| phys_addr_t offset = PFN_PHYS(pgoff); |
| size_t max_nr_pages = fs->window_len/PAGE_SIZE - pgoff; |
| |
| if (kaddr) |
| *kaddr = fs->window_kaddr + offset; |
| if (pfn) |
| *pfn = phys_to_pfn_t(fs->window_phys_addr + offset, |
| PFN_DEV | PFN_MAP); |
| return nr_pages > max_nr_pages ? max_nr_pages : nr_pages; |
| } |
| |
| static size_t virtio_fs_copy_from_iter(struct dax_device *dax_dev, |
| pgoff_t pgoff, void *addr, |
| size_t bytes, struct iov_iter *i) |
| { |
| return copy_from_iter(addr, bytes, i); |
| } |
| |
| static size_t virtio_fs_copy_to_iter(struct dax_device *dax_dev, |
| pgoff_t pgoff, void *addr, |
| size_t bytes, struct iov_iter *i) |
| { |
| return copy_to_iter(addr, bytes, i); |
| } |
| |
| static int virtio_fs_zero_page_range(struct dax_device *dax_dev, |
| pgoff_t pgoff, size_t nr_pages) |
| { |
| long rc; |
| void *kaddr; |
| |
| rc = dax_direct_access(dax_dev, pgoff, nr_pages, &kaddr, NULL); |
| if (rc < 0) |
| return rc; |
| memset(kaddr, 0, nr_pages << PAGE_SHIFT); |
| dax_flush(dax_dev, kaddr, nr_pages << PAGE_SHIFT); |
| return 0; |
| } |
| |
| static const struct dax_operations virtio_fs_dax_ops = { |
| .direct_access = virtio_fs_direct_access, |
| .copy_from_iter = virtio_fs_copy_from_iter, |
| .copy_to_iter = virtio_fs_copy_to_iter, |
| .zero_page_range = virtio_fs_zero_page_range, |
| }; |
| |
| static void virtio_fs_cleanup_dax(void *data) |
| { |
| struct dax_device *dax_dev = data; |
| |
| kill_dax(dax_dev); |
| put_dax(dax_dev); |
| } |
| |
| static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs) |
| { |
| struct virtio_shm_region cache_reg; |
| struct dev_pagemap *pgmap; |
| bool have_cache; |
| |
| if (!IS_ENABLED(CONFIG_FUSE_DAX)) |
| return 0; |
| |
| /* Get cache region */ |
| have_cache = virtio_get_shm_region(vdev, &cache_reg, |
| (u8)VIRTIO_FS_SHMCAP_ID_CACHE); |
| if (!have_cache) { |
| dev_notice(&vdev->dev, "%s: No cache capability\n", __func__); |
| return 0; |
| } |
| |
| if (!devm_request_mem_region(&vdev->dev, cache_reg.addr, cache_reg.len, |
| dev_name(&vdev->dev))) { |
| dev_warn(&vdev->dev, "could not reserve region addr=0x%llx len=0x%llx\n", |
| cache_reg.addr, cache_reg.len); |
| return -EBUSY; |
| } |
| |
| dev_notice(&vdev->dev, "Cache len: 0x%llx @ 0x%llx\n", cache_reg.len, |
| cache_reg.addr); |
| |
| pgmap = devm_kzalloc(&vdev->dev, sizeof(*pgmap), GFP_KERNEL); |
| if (!pgmap) |
| return -ENOMEM; |
| |
| pgmap->type = MEMORY_DEVICE_FS_DAX; |
| |
| /* Ideally we would directly use the PCI BAR resource but |
| * devm_memremap_pages() wants its own copy in pgmap. So |
| * initialize a struct resource from scratch (only the start |
| * and end fields will be used). |
| */ |
| pgmap->range = (struct range) { |
| .start = (phys_addr_t) cache_reg.addr, |
| .end = (phys_addr_t) cache_reg.addr + cache_reg.len - 1, |
| }; |
| pgmap->nr_range = 1; |
| |
| fs->window_kaddr = devm_memremap_pages(&vdev->dev, pgmap); |
| if (IS_ERR(fs->window_kaddr)) |
| return PTR_ERR(fs->window_kaddr); |
| |
| fs->window_phys_addr = (phys_addr_t) cache_reg.addr; |
| fs->window_len = (phys_addr_t) cache_reg.len; |
| |
| dev_dbg(&vdev->dev, "%s: window kaddr 0x%px phys_addr 0x%llx len 0x%llx\n", |
| __func__, fs->window_kaddr, cache_reg.addr, cache_reg.len); |
| |
| fs->dax_dev = alloc_dax(fs, NULL, &virtio_fs_dax_ops, 0); |
| if (IS_ERR(fs->dax_dev)) |
| return PTR_ERR(fs->dax_dev); |
| |
| return devm_add_action_or_reset(&vdev->dev, virtio_fs_cleanup_dax, |
| fs->dax_dev); |
| } |
| |
| static int virtio_fs_probe(struct virtio_device *vdev) |
| { |
| struct virtio_fs *fs; |
| int ret; |
| |
| fs = kzalloc(sizeof(*fs), GFP_KERNEL); |
| if (!fs) |
| return -ENOMEM; |
| kref_init(&fs->refcount); |
| vdev->priv = fs; |
| |
| ret = virtio_fs_read_tag(vdev, fs); |
| if (ret < 0) |
| goto out; |
| |
| ret = virtio_fs_setup_vqs(vdev, fs); |
| if (ret < 0) |
| goto out; |
| |
| /* TODO vq affinity */ |
| |
| ret = virtio_fs_setup_dax(vdev, fs); |
| if (ret < 0) |
| goto out_vqs; |
| |
| /* Bring the device online in case the filesystem is mounted and |
| * requests need to be sent before we return. |
| */ |
| virtio_device_ready(vdev); |
| |
| ret = virtio_fs_add_instance(fs); |
| if (ret < 0) |
| goto out_vqs; |
| |
| return 0; |
| |
| out_vqs: |
| vdev->config->reset(vdev); |
| virtio_fs_cleanup_vqs(vdev, fs); |
| kfree(fs->vqs); |
| |
| out: |
| vdev->priv = NULL; |
| kfree(fs); |
| return ret; |
| } |
| |
| static void virtio_fs_stop_all_queues(struct virtio_fs *fs) |
| { |
| struct virtio_fs_vq *fsvq; |
| int i; |
| |
| for (i = 0; i < fs->nvqs; i++) { |
| fsvq = &fs->vqs[i]; |
| spin_lock(&fsvq->lock); |
| fsvq->connected = false; |
| spin_unlock(&fsvq->lock); |
| } |
| } |
| |
| static void virtio_fs_remove(struct virtio_device *vdev) |
| { |
| struct virtio_fs *fs = vdev->priv; |
| |
| mutex_lock(&virtio_fs_mutex); |
| /* This device is going away. No one should get new reference */ |
| list_del_init(&fs->list); |
| virtio_fs_stop_all_queues(fs); |
| virtio_fs_drain_all_queues_locked(fs); |
| vdev->config->reset(vdev); |
| virtio_fs_cleanup_vqs(vdev, fs); |
| |
| vdev->priv = NULL; |
| /* Put device reference on virtio_fs object */ |
| virtio_fs_put(fs); |
| mutex_unlock(&virtio_fs_mutex); |
| } |
| |
| #ifdef CONFIG_PM_SLEEP |
| static int virtio_fs_freeze(struct virtio_device *vdev) |
| { |
| /* TODO need to save state here */ |
| pr_warn("virtio-fs: suspend/resume not yet supported\n"); |
| return -EOPNOTSUPP; |
| } |
| |
| static int virtio_fs_restore(struct virtio_device *vdev) |
| { |
| /* TODO need to restore state here */ |
| return 0; |
| } |
| #endif /* CONFIG_PM_SLEEP */ |
| |
| static const struct virtio_device_id id_table[] = { |
| { VIRTIO_ID_FS, VIRTIO_DEV_ANY_ID }, |
| {}, |
| }; |
| |
| static const unsigned int feature_table[] = {}; |
| |
| static struct virtio_driver virtio_fs_driver = { |
| .driver.name = KBUILD_MODNAME, |
| .driver.owner = THIS_MODULE, |
| .id_table = id_table, |
| .feature_table = feature_table, |
| .feature_table_size = ARRAY_SIZE(feature_table), |
| .probe = virtio_fs_probe, |
| .remove = virtio_fs_remove, |
| #ifdef CONFIG_PM_SLEEP |
| .freeze = virtio_fs_freeze, |
| .restore = virtio_fs_restore, |
| #endif |
| }; |
| |
| static void virtio_fs_wake_forget_and_unlock(struct fuse_iqueue *fiq) |
| __releases(fiq->lock) |
| { |
| struct fuse_forget_link *link; |
| struct virtio_fs_forget *forget; |
| struct virtio_fs_forget_req *req; |
| struct virtio_fs *fs; |
| struct virtio_fs_vq *fsvq; |
| u64 unique; |
| |
| link = fuse_dequeue_forget(fiq, 1, NULL); |
| unique = fuse_get_unique(fiq); |
| |
| fs = fiq->priv; |
| fsvq = &fs->vqs[VQ_HIPRIO]; |
| spin_unlock(&fiq->lock); |
| |
| /* Allocate a buffer for the request */ |
| forget = kmalloc(sizeof(*forget), GFP_NOFS | __GFP_NOFAIL); |
| req = &forget->req; |
| |
| req->ih = (struct fuse_in_header){ |
| .opcode = FUSE_FORGET, |
| .nodeid = link->forget_one.nodeid, |
| .unique = unique, |
| .len = sizeof(*req), |
| }; |
| req->arg = (struct fuse_forget_in){ |
| .nlookup = link->forget_one.nlookup, |
| }; |
| |
| send_forget_request(fsvq, forget, false); |
| kfree(link); |
| } |
| |
| static void virtio_fs_wake_interrupt_and_unlock(struct fuse_iqueue *fiq) |
| __releases(fiq->lock) |
| { |
| /* |
| * TODO interrupts. |
| * |
| * Normal fs operations on a local filesystems aren't interruptible. |
| * Exceptions are blocking lock operations; for example fcntl(F_SETLKW) |
| * with shared lock between host and guest. |
| */ |
| spin_unlock(&fiq->lock); |
| } |
| |
| /* Count number of scatter-gather elements required */ |
| static unsigned int sg_count_fuse_pages(struct fuse_page_desc *page_descs, |
| unsigned int num_pages, |
| unsigned int total_len) |
| { |
| unsigned int i; |
| unsigned int this_len; |
| |
| for (i = 0; i < num_pages && total_len; i++) { |
| this_len = min(page_descs[i].length, total_len); |
| total_len -= this_len; |
| } |
| |
| return i; |
| } |
| |
| /* Return the number of scatter-gather list elements required */ |
| static unsigned int sg_count_fuse_req(struct fuse_req *req) |
| { |
| struct fuse_args *args = req->args; |
| struct fuse_args_pages *ap = container_of(args, typeof(*ap), args); |
| unsigned int size, total_sgs = 1 /* fuse_in_header */; |
| |
| if (args->in_numargs - args->in_pages) |
| total_sgs += 1; |
| |
| if (args->in_pages) { |
| size = args->in_args[args->in_numargs - 1].size; |
| total_sgs += sg_count_fuse_pages(ap->descs, ap->num_pages, |
| size); |
| } |
| |
| if (!test_bit(FR_ISREPLY, &req->flags)) |
| return total_sgs; |
| |
| total_sgs += 1 /* fuse_out_header */; |
| |
| if (args->out_numargs - args->out_pages) |
| total_sgs += 1; |
| |
| if (args->out_pages) { |
| size = args->out_args[args->out_numargs - 1].size; |
| total_sgs += sg_count_fuse_pages(ap->descs, ap->num_pages, |
| size); |
| } |
| |
| return total_sgs; |
| } |
| |
| /* Add pages to scatter-gather list and return number of elements used */ |
| static unsigned int sg_init_fuse_pages(struct scatterlist *sg, |
| struct page **pages, |
| struct fuse_page_desc *page_descs, |
| unsigned int num_pages, |
| unsigned int total_len) |
| { |
| unsigned int i; |
| unsigned int this_len; |
| |
| for (i = 0; i < num_pages && total_len; i++) { |
| sg_init_table(&sg[i], 1); |
| this_len = min(page_descs[i].length, total_len); |
| sg_set_page(&sg[i], pages[i], this_len, page_descs[i].offset); |
| total_len -= this_len; |
| } |
| |
| return i; |
| } |
| |
| /* Add args to scatter-gather list and return number of elements used */ |
| static unsigned int sg_init_fuse_args(struct scatterlist *sg, |
| struct fuse_req *req, |
| struct fuse_arg *args, |
| unsigned int numargs, |
| bool argpages, |
| void *argbuf, |
| unsigned int *len_used) |
| { |
| struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args); |
| unsigned int total_sgs = 0; |
| unsigned int len; |
| |
| len = fuse_len_args(numargs - argpages, args); |
| if (len) |
| sg_init_one(&sg[total_sgs++], argbuf, len); |
| |
| if (argpages) |
| total_sgs += sg_init_fuse_pages(&sg[total_sgs], |
| ap->pages, ap->descs, |
| ap->num_pages, |
| args[numargs - 1].size); |
| |
| if (len_used) |
| *len_used = len; |
| |
| return total_sgs; |
| } |
| |
| /* Add a request to a virtqueue and kick the device */ |
| static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq, |
| struct fuse_req *req, bool in_flight) |
| { |
| /* requests need at least 4 elements */ |
| struct scatterlist *stack_sgs[6]; |
| struct scatterlist stack_sg[ARRAY_SIZE(stack_sgs)]; |
| struct scatterlist **sgs = stack_sgs; |
| struct scatterlist *sg = stack_sg; |
| struct virtqueue *vq; |
| struct fuse_args *args = req->args; |
| unsigned int argbuf_used = 0; |
| unsigned int out_sgs = 0; |
| unsigned int in_sgs = 0; |
| unsigned int total_sgs; |
| unsigned int i; |
| int ret; |
| bool notify; |
| struct fuse_pqueue *fpq; |
| |
| /* Does the sglist fit on the stack? */ |
| total_sgs = sg_count_fuse_req(req); |
| if (total_sgs > ARRAY_SIZE(stack_sgs)) { |
| sgs = kmalloc_array(total_sgs, sizeof(sgs[0]), GFP_ATOMIC); |
| sg = kmalloc_array(total_sgs, sizeof(sg[0]), GFP_ATOMIC); |
| if (!sgs || !sg) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| } |
| |
| /* Use a bounce buffer since stack args cannot be mapped */ |
| ret = copy_args_to_argbuf(req); |
| if (ret < 0) |
| goto out; |
| |
| /* Request elements */ |
| sg_init_one(&sg[out_sgs++], &req->in.h, sizeof(req->in.h)); |
| out_sgs += sg_init_fuse_args(&sg[out_sgs], req, |
| (struct fuse_arg *)args->in_args, |
| args->in_numargs, args->in_pages, |
| req->argbuf, &argbuf_used); |
| |
| /* Reply elements */ |
| if (test_bit(FR_ISREPLY, &req->flags)) { |
| sg_init_one(&sg[out_sgs + in_sgs++], |
| &req->out.h, sizeof(req->out.h)); |
| in_sgs += sg_init_fuse_args(&sg[out_sgs + in_sgs], req, |
| args->out_args, args->out_numargs, |
| args->out_pages, |
| req->argbuf + argbuf_used, NULL); |
| } |
| |
| WARN_ON(out_sgs + in_sgs != total_sgs); |
| |
| for (i = 0; i < total_sgs; i++) |
| sgs[i] = &sg[i]; |
| |
| spin_lock(&fsvq->lock); |
| |
| if (!fsvq->connected) { |
| spin_unlock(&fsvq->lock); |
| ret = -ENOTCONN; |
| goto out; |
| } |
| |
| vq = fsvq->vq; |
| ret = virtqueue_add_sgs(vq, sgs, out_sgs, in_sgs, req, GFP_ATOMIC); |
| if (ret < 0) { |
| spin_unlock(&fsvq->lock); |
| goto out; |
| } |
| |
| /* Request successfully sent. */ |
| fpq = &fsvq->fud->pq; |
| spin_lock(&fpq->lock); |
| list_add_tail(&req->list, fpq->processing); |
| spin_unlock(&fpq->lock); |
| set_bit(FR_SENT, &req->flags); |
| /* matches barrier in request_wait_answer() */ |
| smp_mb__after_atomic(); |
| |
| if (!in_flight) |
| inc_in_flight_req(fsvq); |
| notify = virtqueue_kick_prepare(vq); |
| |
| spin_unlock(&fsvq->lock); |
| |
| if (notify) |
| virtqueue_notify(vq); |
| |
| out: |
| if (ret < 0 && req->argbuf) { |
| kfree(req->argbuf); |
| req->argbuf = NULL; |
| } |
| if (sgs != stack_sgs) { |
| kfree(sgs); |
| kfree(sg); |
| } |
| |
| return ret; |
| } |
| |
| static void virtio_fs_wake_pending_and_unlock(struct fuse_iqueue *fiq) |
| __releases(fiq->lock) |
| { |
| unsigned int queue_id = VQ_REQUEST; /* TODO multiqueue */ |
| struct virtio_fs *fs; |
| struct fuse_req *req; |
| struct virtio_fs_vq *fsvq; |
| int ret; |
| |
| WARN_ON(list_empty(&fiq->pending)); |
| req = list_last_entry(&fiq->pending, struct fuse_req, list); |
| clear_bit(FR_PENDING, &req->flags); |
| list_del_init(&req->list); |
| WARN_ON(!list_empty(&fiq->pending)); |
| spin_unlock(&fiq->lock); |
| |
| fs = fiq->priv; |
| |
| pr_debug("%s: opcode %u unique %#llx nodeid %#llx in.len %u out.len %u\n", |
| __func__, req->in.h.opcode, req->in.h.unique, |
| req->in.h.nodeid, req->in.h.len, |
| fuse_len_args(req->args->out_numargs, req->args->out_args)); |
| |
| fsvq = &fs->vqs[queue_id]; |
| ret = virtio_fs_enqueue_req(fsvq, req, false); |
| if (ret < 0) { |
| if (ret == -ENOMEM || ret == -ENOSPC) { |
| /* |
| * Virtqueue full. Retry submission from worker |
| * context as we might be holding fc->bg_lock. |
| */ |
| spin_lock(&fsvq->lock); |
| list_add_tail(&req->list, &fsvq->queued_reqs); |
| inc_in_flight_req(fsvq); |
| schedule_delayed_work(&fsvq->dispatch_work, |
| msecs_to_jiffies(1)); |
| spin_unlock(&fsvq->lock); |
| return; |
| } |
| req->out.h.error = ret; |
| pr_err("virtio-fs: virtio_fs_enqueue_req() failed %d\n", ret); |
| |
| /* Can't end request in submission context. Use a worker */ |
| spin_lock(&fsvq->lock); |
| list_add_tail(&req->list, &fsvq->end_reqs); |
| schedule_delayed_work(&fsvq->dispatch_work, 0); |
| spin_unlock(&fsvq->lock); |
| return; |
| } |
| } |
| |
| static const struct fuse_iqueue_ops virtio_fs_fiq_ops = { |
| .wake_forget_and_unlock = virtio_fs_wake_forget_and_unlock, |
| .wake_interrupt_and_unlock = virtio_fs_wake_interrupt_and_unlock, |
| .wake_pending_and_unlock = virtio_fs_wake_pending_and_unlock, |
| .release = virtio_fs_fiq_release, |
| }; |
| |
| static inline void virtio_fs_ctx_set_defaults(struct fuse_fs_context *ctx) |
| { |
| ctx->rootmode = S_IFDIR; |
| ctx->default_permissions = 1; |
| ctx->allow_other = 1; |
| ctx->max_read = UINT_MAX; |
| ctx->blksize = 512; |
| ctx->destroy = true; |
| ctx->no_control = true; |
| ctx->no_force_umount = true; |
| } |
| |
| static int virtio_fs_fill_super(struct super_block *sb, struct fs_context *fsc) |
| { |
| struct fuse_mount *fm = get_fuse_mount_super(sb); |
| struct fuse_conn *fc = fm->fc; |
| struct virtio_fs *fs = fc->iq.priv; |
| struct fuse_fs_context *ctx = fsc->fs_private; |
| unsigned int i; |
| int err; |
| |
| virtio_fs_ctx_set_defaults(ctx); |
| mutex_lock(&virtio_fs_mutex); |
| |
| /* After holding mutex, make sure virtiofs device is still there. |
| * Though we are holding a reference to it, drive ->remove might |
| * still have cleaned up virtual queues. In that case bail out. |
| */ |
| err = -EINVAL; |
| if (list_empty(&fs->list)) { |
| pr_info("virtio-fs: tag <%s> not found\n", fs->tag); |
| goto err; |
| } |
| |
| err = -ENOMEM; |
| /* Allocate fuse_dev for hiprio and notification queues */ |
| for (i = 0; i < fs->nvqs; i++) { |
| struct virtio_fs_vq *fsvq = &fs->vqs[i]; |
| |
| fsvq->fud = fuse_dev_alloc(); |
| if (!fsvq->fud) |
| goto err_free_fuse_devs; |
| } |
| |
| /* virtiofs allocates and installs its own fuse devices */ |
| ctx->fudptr = NULL; |
| if (ctx->dax) { |
| if (!fs->dax_dev) { |
| err = -EINVAL; |
| pr_err("virtio-fs: dax can't be enabled as filesystem" |
| " device does not support it.\n"); |
| goto err_free_fuse_devs; |
| } |
| ctx->dax_dev = fs->dax_dev; |
| } |
| err = fuse_fill_super_common(sb, ctx); |
| if (err < 0) |
| goto err_free_fuse_devs; |
| |
| for (i = 0; i < fs->nvqs; i++) { |
| struct virtio_fs_vq *fsvq = &fs->vqs[i]; |
| |
| fuse_dev_install(fsvq->fud, fc); |
| } |
| |
| /* Previous unmount will stop all queues. Start these again */ |
| virtio_fs_start_all_queues(fs); |
| fuse_send_init(fm); |
| mutex_unlock(&virtio_fs_mutex); |
| return 0; |
| |
| err_free_fuse_devs: |
| virtio_fs_free_devs(fs); |
| err: |
| mutex_unlock(&virtio_fs_mutex); |
| return err; |
| } |
| |
| static void virtio_fs_conn_destroy(struct fuse_mount *fm) |
| { |
| struct fuse_conn *fc = fm->fc; |
| struct virtio_fs *vfs = fc->iq.priv; |
| struct virtio_fs_vq *fsvq = &vfs->vqs[VQ_HIPRIO]; |
| |
| /* Stop dax worker. Soon evict_inodes() will be called which |
| * will free all memory ranges belonging to all inodes. |
| */ |
| if (IS_ENABLED(CONFIG_FUSE_DAX)) |
| fuse_dax_cancel_work(fc); |
| |
| /* Stop forget queue. Soon destroy will be sent */ |
| spin_lock(&fsvq->lock); |
| fsvq->connected = false; |
| spin_unlock(&fsvq->lock); |
| virtio_fs_drain_all_queues(vfs); |
| |
| fuse_conn_destroy(fm); |
| |
| /* fuse_conn_destroy() must have sent destroy. Stop all queues |
| * and drain one more time and free fuse devices. Freeing fuse |
| * devices will drop their reference on fuse_conn and that in |
| * turn will drop its reference on virtio_fs object. |
| */ |
| virtio_fs_stop_all_queues(vfs); |
| virtio_fs_drain_all_queues(vfs); |
| virtio_fs_free_devs(vfs); |
| } |
| |
| static void virtio_kill_sb(struct super_block *sb) |
| { |
| struct fuse_mount *fm = get_fuse_mount_super(sb); |
| bool last; |
| |
| /* If mount failed, we can still be called without any fc */ |
| if (fm) { |
| last = fuse_mount_remove(fm); |
| if (last) |
| virtio_fs_conn_destroy(fm); |
| } |
| kill_anon_super(sb); |
| } |
| |
| static int virtio_fs_test_super(struct super_block *sb, |
| struct fs_context *fsc) |
| { |
| struct fuse_mount *fsc_fm = fsc->s_fs_info; |
| struct fuse_mount *sb_fm = get_fuse_mount_super(sb); |
| |
| return fsc_fm->fc->iq.priv == sb_fm->fc->iq.priv; |
| } |
| |
| static int virtio_fs_get_tree(struct fs_context *fsc) |
| { |
| struct virtio_fs *fs; |
| struct super_block *sb; |
| struct fuse_conn *fc = NULL; |
| struct fuse_mount *fm; |
| unsigned int virtqueue_size; |
| int err = -EIO; |
| |
| /* This gets a reference on virtio_fs object. This ptr gets installed |
| * in fc->iq->priv. Once fuse_conn is going away, it calls ->put() |
| * to drop the reference to this object. |
| */ |
| fs = virtio_fs_find_instance(fsc->source); |
| if (!fs) { |
| pr_info("virtio-fs: tag <%s> not found\n", fsc->source); |
| return -EINVAL; |
| } |
| |
| virtqueue_size = virtqueue_get_vring_size(fs->vqs[VQ_REQUEST].vq); |
| if (WARN_ON(virtqueue_size <= FUSE_HEADER_OVERHEAD)) |
| goto out_err; |
| |
| err = -ENOMEM; |
| fc = kzalloc(sizeof(struct fuse_conn), GFP_KERNEL); |
| if (!fc) |
| goto out_err; |
| |
| fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); |
| if (!fm) |
| goto out_err; |
| |
| fuse_conn_init(fc, fm, fsc->user_ns, &virtio_fs_fiq_ops, fs); |
| fc->release = fuse_free_conn; |
| fc->delete_stale = true; |
| fc->auto_submounts = true; |
| fc->sync_fs = true; |
| |
| /* Tell FUSE to split requests that exceed the virtqueue's size */ |
| fc->max_pages_limit = min_t(unsigned int, fc->max_pages_limit, |
| virtqueue_size - FUSE_HEADER_OVERHEAD); |
| |
| fsc->s_fs_info = fm; |
| sb = sget_fc(fsc, virtio_fs_test_super, set_anon_super_fc); |
| if (fsc->s_fs_info) { |
| fuse_conn_put(fc); |
| kfree(fm); |
| } |
| if (IS_ERR(sb)) |
| return PTR_ERR(sb); |
| |
| if (!sb->s_root) { |
| err = virtio_fs_fill_super(sb, fsc); |
| if (err) { |
| fuse_conn_put(fc); |
| kfree(fm); |
| sb->s_fs_info = NULL; |
| deactivate_locked_super(sb); |
| return err; |
| } |
| |
| sb->s_flags |= SB_ACTIVE; |
| } |
| |
| WARN_ON(fsc->root); |
| fsc->root = dget(sb->s_root); |
| return 0; |
| |
| out_err: |
| kfree(fc); |
| mutex_lock(&virtio_fs_mutex); |
| virtio_fs_put(fs); |
| mutex_unlock(&virtio_fs_mutex); |
| return err; |
| } |
| |
| static const struct fs_context_operations virtio_fs_context_ops = { |
| .free = virtio_fs_free_fc, |
| .parse_param = virtio_fs_parse_param, |
| .get_tree = virtio_fs_get_tree, |
| }; |
| |
| static int virtio_fs_init_fs_context(struct fs_context *fsc) |
| { |
| struct fuse_fs_context *ctx; |
| |
| if (fsc->purpose == FS_CONTEXT_FOR_SUBMOUNT) |
| return fuse_init_fs_context_submount(fsc); |
| |
| ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL); |
| if (!ctx) |
| return -ENOMEM; |
| fsc->fs_private = ctx; |
| fsc->ops = &virtio_fs_context_ops; |
| return 0; |
| } |
| |
| static struct file_system_type virtio_fs_type = { |
| .owner = THIS_MODULE, |
| .name = "virtiofs", |
| .init_fs_context = virtio_fs_init_fs_context, |
| .kill_sb = virtio_kill_sb, |
| }; |
| |
| static int __init virtio_fs_init(void) |
| { |
| int ret; |
| |
| ret = register_virtio_driver(&virtio_fs_driver); |
| if (ret < 0) |
| return ret; |
| |
| ret = register_filesystem(&virtio_fs_type); |
| if (ret < 0) { |
| unregister_virtio_driver(&virtio_fs_driver); |
| return ret; |
| } |
| |
| return 0; |
| } |
| module_init(virtio_fs_init); |
| |
| static void __exit virtio_fs_exit(void) |
| { |
| unregister_filesystem(&virtio_fs_type); |
| unregister_virtio_driver(&virtio_fs_driver); |
| } |
| module_exit(virtio_fs_exit); |
| |
| MODULE_AUTHOR("Stefan Hajnoczi <stefanha@redhat.com>"); |
| MODULE_DESCRIPTION("Virtio Filesystem"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS_FS(KBUILD_MODNAME); |
| MODULE_DEVICE_TABLE(virtio, id_table); |