diff options
| -rw-r--r-- | fs/fuse/fuse_i.h | 3 | ||||
| -rw-r--r-- | fs/fuse/inode.c | 3 | ||||
| -rw-r--r-- | fs/fuse/virtio_fs.c | 19 |
3 files changed, 22 insertions, 3 deletions
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 979b680bb47e..38369a5094af 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -555,6 +555,9 @@ struct fuse_conn { /** Maximum number of pages that can be used in a single request */ unsigned int max_pages; + /** Constrain ->max_pages to this value during feature negotiation */ + unsigned int max_pages_limit; + /** Input queue */ struct fuse_iqueue iq; diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 06a68cfa76d8..2f3161bb4b1c 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -712,6 +712,7 @@ void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, fc->pid_ns = get_pid_ns(task_active_pid_ns(current)); fc->user_ns = get_user_ns(user_ns); fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ; + fc->max_pages_limit = FUSE_MAX_MAX_PAGES; INIT_LIST_HEAD(&fc->mounts); list_add(&fm->fc_entry, &fc->mounts); @@ -1040,7 +1041,7 @@ static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, fc->abort_err = 1; if (arg->flags & FUSE_MAX_PAGES) { fc->max_pages = - min_t(unsigned int, FUSE_MAX_MAX_PAGES, + min_t(unsigned int, fc->max_pages_limit, max_t(unsigned int, arg->max_pages, 1)); } if (IS_ENABLED(CONFIG_FUSE_DAX) && diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index 1e5affed158e..b55e977f50ac 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -18,6 +18,12 @@ #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 */ @@ -1414,9 +1420,10 @@ static int virtio_fs_get_tree(struct fs_context *fsc) { struct virtio_fs *fs; struct super_block *sb; - struct fuse_conn *fc; + struct fuse_conn *fc = NULL; struct fuse_mount *fm; - int err; + 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() @@ -1428,6 +1435,10 @@ static int virtio_fs_get_tree(struct fs_context *fsc) 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) @@ -1443,6 +1454,10 @@ static int virtio_fs_get_tree(struct fs_context *fsc) fc->delete_stale = true; fc->auto_submounts = 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) { |