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{
    "id": 2194215,
    "url": "http://patchwork.ozlabs.org/api/patches/2194215/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260207120901.17222-5-hibriansong@gmail.com/",
    "project": {
        "id": 14,
        "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api",
        "name": "QEMU Development",
        "link_name": "qemu-devel",
        "list_id": "qemu-devel.nongnu.org",
        "list_email": "qemu-devel@nongnu.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": "",
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<20260207120901.17222-5-hibriansong@gmail.com>",
    "list_archive_url": null,
    "date": "2026-02-07T12:08:58",
    "name": "[v4,4/7] fuse: refactor FUSE request handler",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "f439e415021ba1d1563fffe49af7f4552e510b51",
    "submitter": {
        "id": 90672,
        "url": "http://patchwork.ozlabs.org/api/people/90672/?format=api",
        "name": "Brian Song",
        "email": "hibriansong@gmail.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260207120901.17222-5-hibriansong@gmail.com/mbox/",
    "series": [
        {
            "id": 491376,
            "url": "http://patchwork.ozlabs.org/api/series/491376/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=491376",
            "date": "2026-02-07T12:08:56",
            "name": "add fuse-over-io_uring support",
            "version": 4,
            "mbox": "http://patchwork.ozlabs.org/series/491376/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/2194215/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/2194215/checks/",
    "tags": {},
    "related": [],
    "headers": {
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        "From": "Brian Song <hibriansong@gmail.com>",
        "To": "qemu-block@nongnu.org",
        "Cc": "qemu-devel@nongnu.org, hibriansong@gmail.com, hreitz@redhat.com,\n kwolf@redhat.com, eblake@redhat.com, armbru@redhat.com,\n stefanha@redhat.com, fam@euphon.net, bernd@bsbernd.com",
        "Subject": "[Patch v4 4/7] fuse: refactor FUSE request handler",
        "Date": "Sat,  7 Feb 2026 20:08:58 +0800",
        "Message-ID": "<20260207120901.17222-5-hibriansong@gmail.com>",
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        "References": "<20260207120901.17222-1-hibriansong@gmail.com>",
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    },
    "content": "This patch implements the CQE handler for FUSE-over-io_uring. Upon\nreceiving a FUSE request via a Completion Queue Entry (CQE), the\nhandler processes the request and submits the response back to the\nkernel via the FUSE_IO_URING_CMD_COMMIT_AND_FETCH command.\n\nAdditionally, the request processing logic shared between legacy and\nio_uring modes has been extracted into fuse_co_process_request_common().\nThe execution flow now dispatches requests to the appropriate\nmode-specific logic based on the uring_started flag.\n\nSuggested-by: Kevin Wolf <kwolf@redhat.com>\nSuggested-by: Stefan Hajnoczi <stefanha@redhat.com>\nSigned-off-by: Brian Song <hibriansong@gmail.com>\n---\n block/export/fuse.c | 400 +++++++++++++++++++++++++++++++++-----------\n 1 file changed, 301 insertions(+), 99 deletions(-)\n\n--\n2.43.0",
    "diff": "diff --git a/block/export/fuse.c b/block/export/fuse.c\nindex 867752555a..c117e081cd 100644\n--- a/block/export/fuse.c\n+++ b/block/export/fuse.c\n@@ -138,8 +138,8 @@ struct FuseQueue {\n      * FUSE_MIN_READ_BUFFER (from linux/fuse.h) bytes.\n      * This however is just the first part of the buffer; every read is given\n      * a vector of this buffer (which should be enough for all normal requests,\n-     * which we check via the static assertion in FUSE_IN_OP_STRUCT()) and the\n-     * spill-over buffer below.\n+     * which we check via the static assertion in FUSE_IN_OP_STRUCT_LEGACY())\n+     * and the spill-over buffer below.\n      * Therefore, the size of this buffer plus FUSE_SPILLOVER_BUF_SIZE must be\n      * FUSE_MIN_READ_BUFFER or more (checked via static assertion below).\n      */\n@@ -912,6 +912,7 @@ static void coroutine_fn co_read_from_fuse_fd(void *opaque)\n     }\n\n     fuse_co_process_request(q, spillover_buf);\n+    qemu_vfree(spillover_buf);\n\n no_request:\n     fuse_dec_in_flight(exp);\n@@ -1684,100 +1685,75 @@ static int fuse_write_buf_response(int fd, uint32_t req_id,\n }\n\n /*\n- * For use in fuse_co_process_request():\n+ * For use in fuse_co_process_request_common():\n  * Returns a pointer to the parameter object for the given operation (inside of\n- * queue->request_buf, which is assumed to hold a fuse_in_header first).\n- * Verifies that the object is complete (queue->request_buf is large enough to\n- * hold it in one piece, and the request length includes the whole object).\n+ * in_buf, which is assumed to hold a fuse_in_header first).\n+ * Verifies that the object is complete (in_buf is large enough to hold it in\n+ * one piece, and the request length includes the whole object).\n+ * Only performs verification for legacy FUSE.\n  *\n  * Note that queue->request_buf may be overwritten after yielding, so the\n  * returned pointer must not be used across a function that may yield!\n  */\n-#define FUSE_IN_OP_STRUCT(op_name, queue) \\\n+#define FUSE_IN_OP_STRUCT_LEGACY(op_name, queue) \\\n     ({ \\\n         const struct fuse_in_header *__in_hdr = \\\n             (const struct fuse_in_header *)(queue)->request_buf; \\\n         const struct fuse_##op_name##_in *__in = \\\n             (const struct fuse_##op_name##_in *)(__in_hdr + 1); \\\n         const size_t __param_len = sizeof(*__in_hdr) + sizeof(*__in); \\\n-        uint32_t __req_len; \\\n         \\\n-        QEMU_BUILD_BUG_ON(sizeof((queue)->request_buf) < __param_len); \\\n+        QEMU_BUILD_BUG_ON(sizeof((queue)->request_buf) < \\\n+                          (sizeof(struct fuse_in_header) + \\\n+                           sizeof(struct fuse_##op_name##_in))); \\\n         \\\n-        __req_len = __in_hdr->len; \\\n+        uint32_t __req_len = __in_hdr->len; \\\n         if (__req_len < __param_len) { \\\n             warn_report(\"FUSE request truncated (%\" PRIu32 \" < %zu)\", \\\n                         __req_len, __param_len); \\\n             ret = -EINVAL; \\\n-            break; \\\n+            __in = NULL; \\\n         } \\\n         __in; \\\n     })\n\n /*\n- * For use in fuse_co_process_request():\n+ * For use in fuse_co_process_request_common():\n  * Returns a pointer to the return object for the given operation (inside of\n  * out_buf, which is assumed to hold a fuse_out_header first).\n- * Verifies that out_buf is large enough to hold the whole object.\n+ * Only performs verification for legacy FUSE.\n+ * Note: Buffer size verification is done via static assertions in the caller\n+ * (fuse_co_process_request) where out_buf is a local array.\n  *\n- * (out_buf should be a char[] array.)\n+ * (out_buf should be a char[] array in the caller.)\n  */\n-#define FUSE_OUT_OP_STRUCT(op_name, out_buf) \\\n+#define FUSE_OUT_OP_STRUCT_LEGACY(op_name, out_buf) \\\n     ({ \\\n         struct fuse_out_header *__out_hdr = \\\n             (struct fuse_out_header *)(out_buf); \\\n         struct fuse_##op_name##_out *__out = \\\n             (struct fuse_##op_name##_out *)(__out_hdr + 1); \\\n         \\\n-        QEMU_BUILD_BUG_ON(sizeof(*__out_hdr) + sizeof(*__out) > \\\n-                          sizeof(out_buf)); \\\n-        \\\n         __out; \\\n     })\n\n /**\n- * Process a FUSE request, incl. writing the response.\n- *\n- * Note that yielding in any request-processing function can overwrite the\n- * contents of q->request_buf.  Anything that takes a buffer needs to take\n- * care that the content is copied before yielding.\n- *\n- * @spillover_buf can contain the tail of a write request too large to fit into\n- * q->request_buf.  This function takes ownership of it (i.e. will free it),\n- * which assumes that its contents will not be overwritten by concurrent\n- * requests (as opposed to q->request_buf).\n+ * Shared helper for FUSE request processing. Handles both legacy and io_uring\n+ * paths.\n  */\n-static void coroutine_fn\n-fuse_co_process_request(FuseQueue *q, void *spillover_buf)\n+static void coroutine_fn fuse_co_process_request_common(\n+    FuseExport *exp,\n+    uint32_t opcode,\n+    uint64_t req_id,\n+    void *in_buf,\n+    void *spillover_buf,\n+    void *out_buf,\n+    void (*send_response)(void *opaque, uint32_t req_id, int ret,\n+                          const void *buf, void *out_buf),\n+    void *opaque /* FuseQueue* or FuseUringEnt* */)\n {\n-    FuseExport *exp = q->exp;\n-    uint32_t opcode;\n-    uint64_t req_id;\n-    /*\n-     * Return buffer.  Must be large enough to hold all return headers, but does\n-     * not include space for data returned by read requests.\n-     * (FUSE_IN_OP_STRUCT() verifies at compile time that out_buf is indeed\n-     * large enough.)\n-     */\n-    char out_buf[sizeof(struct fuse_out_header) +\n-                 MAX_CONST(sizeof(struct fuse_init_out),\n-                 MAX_CONST(sizeof(struct fuse_open_out),\n-                 MAX_CONST(sizeof(struct fuse_attr_out),\n-                 MAX_CONST(sizeof(struct fuse_write_out),\n-                           sizeof(struct fuse_lseek_out)))))];\n-    struct fuse_out_header *out_hdr = (struct fuse_out_header *)out_buf;\n-    /* For read requests: Data to be returned */\n     void *out_data_buffer = NULL;\n-    ssize_t ret;\n-\n-    /* Limit scope to ensure pointer is no longer used after yielding */\n-    {\n-        const struct fuse_in_header *in_hdr =\n-            (const struct fuse_in_header *)q->request_buf;\n-\n-        opcode = in_hdr->opcode;\n-        req_id = in_hdr->unique;\n-    }\n+    int ret = 0;\n\n #ifdef CONFIG_LINUX_IO_URING\n     /*\n@@ -1794,15 +1770,32 @@ fuse_co_process_request(FuseQueue *q, void *spillover_buf)\n\n     switch (opcode) {\n     case FUSE_INIT: {\n-        const struct fuse_init_in *in = FUSE_IN_OP_STRUCT(init, q);\n-        ret = fuse_co_init(exp, FUSE_OUT_OP_STRUCT(init, out_buf),\n-                           in->max_readahead, in);\n+        FuseQueue *q = opaque;\n+        const struct fuse_init_in *in =\n+            FUSE_IN_OP_STRUCT_LEGACY(init, q);\n+        if (!in) {\n+            break;\n+        }\n+\n+        struct fuse_init_out *out =\n+            FUSE_OUT_OP_STRUCT_LEGACY(init, out_buf);\n+\n+        ret = fuse_co_init(exp, out, in->max_readahead, in);\n         break;\n     }\n\n-    case FUSE_OPEN:\n-        ret = fuse_co_open(exp, FUSE_OUT_OP_STRUCT(open, out_buf));\n+    case FUSE_OPEN: {\n+        struct fuse_open_out *out;\n+\n+        if (exp->uring_started) {\n+            out = out_buf;\n+        } else {\n+            out = FUSE_OUT_OP_STRUCT_LEGACY(open, out_buf);\n+        }\n+\n+        ret = fuse_co_open(exp, out);\n         break;\n+    }\n\n     case FUSE_RELEASE:\n         ret = 0;\n@@ -1812,37 +1805,105 @@ fuse_co_process_request(FuseQueue *q, void *spillover_buf)\n         ret = -ENOENT; /* There is no node but the root node */\n         break;\n\n-    case FUSE_GETATTR:\n-        ret = fuse_co_getattr(exp, FUSE_OUT_OP_STRUCT(attr, out_buf));\n+    case FUSE_GETATTR: {\n+        struct fuse_attr_out *out;\n+\n+        if (exp->uring_started) {\n+            out = out_buf;\n+        } else {\n+            out = FUSE_OUT_OP_STRUCT_LEGACY(attr, out_buf);\n+        }\n+\n+        ret = fuse_co_getattr(exp, out);\n         break;\n+    }\n\n     case FUSE_SETATTR: {\n-        const struct fuse_setattr_in *in = FUSE_IN_OP_STRUCT(setattr, q);\n-        ret = fuse_co_setattr(exp, FUSE_OUT_OP_STRUCT(attr, out_buf),\n-                              in->valid, in->size, in->mode, in->uid, in->gid);\n+        const struct fuse_setattr_in *in;\n+        struct fuse_attr_out *out;\n+\n+        if (exp->uring_started) {\n+            in = in_buf;\n+            out = out_buf;\n+        } else {\n+            FuseQueue *q = opaque;\n+            in = FUSE_IN_OP_STRUCT_LEGACY(setattr, q);\n+            if (!in) {\n+                break;\n+            }\n+\n+            out = FUSE_OUT_OP_STRUCT_LEGACY(attr, out_buf);\n+        }\n+\n+        ret = fuse_co_setattr(exp, out, in->valid, in->size, in->mode,\n+                              in->uid, in->gid);\n         break;\n     }\n\n     case FUSE_READ: {\n-        const struct fuse_read_in *in = FUSE_IN_OP_STRUCT(read, q);\n+        const struct fuse_read_in *in;\n+\n+        if (exp->uring_started) {\n+            in = in_buf;\n+        } else {\n+            FuseQueue *q = opaque;\n+            in = FUSE_IN_OP_STRUCT_LEGACY(read, q);\n+            if (!in) {\n+                break;\n+            }\n+        }\n+\n         ret = fuse_co_read(exp, &out_data_buffer, in->offset, in->size);\n         break;\n     }\n\n     case FUSE_WRITE: {\n-        const struct fuse_write_in *in = FUSE_IN_OP_STRUCT(write, q);\n-        uint32_t req_len;\n-\n-        req_len = ((const struct fuse_in_header *)q->request_buf)->len;\n-        if (unlikely(req_len < sizeof(struct fuse_in_header) + sizeof(*in) +\n-                               in->size)) {\n-            warn_report(\"FUSE WRITE truncated; received %zu bytes of %\" PRIu32,\n-                        req_len - sizeof(struct fuse_in_header) - sizeof(*in),\n-                        in->size);\n-            ret = -EINVAL;\n-            break;\n-        }\n+        const struct fuse_write_in *in;\n+        struct fuse_write_out *out;\n+        const void *in_place_buf;\n+        const void *spill_buf;\n+\n+        if (exp->uring_started) {\n+            FuseUringEnt *ent = opaque;\n+\n+            in = in_buf;\n+            out = out_buf;\n+\n+            assert(in->size <= ent->req_header.ring_ent_in_out.payload_sz);\n\n+            /*\n+             * In uring mode, the \"out_buf\" (ent->payload) actually holds the\n+             * input data for WRITE requests.\n+             */\n+            in_place_buf = NULL;\n+            spill_buf = out_buf;\n+        } else {\n+            FuseQueue *q = opaque;\n+            in = FUSE_IN_OP_STRUCT_LEGACY(write, q);\n+            if (!in) {\n+                break;\n+            }\n+\n+            out = FUSE_OUT_OP_STRUCT_LEGACY(write, out_buf);\n+\n+            /* Additional check for WRITE: verify the request includes data */\n+            uint32_t req_len =\n+                ((const struct fuse_in_header *)(q->request_buf))->len;\n+\n+            if (unlikely(req_len < sizeof(struct fuse_in_header) + sizeof(*in) +\n+                        in->size)) {\n+                warn_report(\"FUSE WRITE truncated; received %zu bytes of %\"\n+                    PRIu32,\n+                    req_len - sizeof(struct fuse_in_header) - sizeof(*in),\n+                    in->size);\n+                ret = -EINVAL;\n+                break;\n+            }\n+\n+            /* Legacy buffer setup */\n+            in_place_buf = in + 1;\n+            spill_buf = spillover_buf;\n+        }\n         /*\n          * poll_fuse_fd() has checked that in_hdr->len matches the number of\n          * bytes read, which cannot exceed the max_write value we set\n@@ -1856,13 +1917,24 @@ fuse_co_process_request(FuseQueue *q, void *spillover_buf)\n          * fuse_co_write() takes care to copy its contents before potentially\n          * yielding.\n          */\n-        ret = fuse_co_write(exp, FUSE_OUT_OP_STRUCT(write, out_buf),\n-                            in->offset, in->size, in + 1, spillover_buf);\n+        ret = fuse_co_write(exp, out, in->offset, in->size,\n+                            in_place_buf, spill_buf);\n         break;\n     }\n\n     case FUSE_FALLOCATE: {\n-        const struct fuse_fallocate_in *in = FUSE_IN_OP_STRUCT(fallocate, q);\n+        const struct fuse_fallocate_in *in;\n+\n+        if (exp->uring_started) {\n+            in = in_buf;\n+        } else {\n+            FuseQueue *q = opaque;\n+            in = FUSE_IN_OP_STRUCT_LEGACY(fallocate, q);\n+            if (!in) {\n+                break;\n+            }\n+        }\n+\n         ret = fuse_co_fallocate(exp, in->offset, in->length, in->mode);\n         break;\n     }\n@@ -1877,9 +1949,23 @@ fuse_co_process_request(FuseQueue *q, void *spillover_buf)\n\n #ifdef CONFIG_FUSE_LSEEK\n     case FUSE_LSEEK: {\n-        const struct fuse_lseek_in *in = FUSE_IN_OP_STRUCT(lseek, q);\n-        ret = fuse_co_lseek(exp, FUSE_OUT_OP_STRUCT(lseek, out_buf),\n-                            in->offset, in->whence);\n+        const struct fuse_lseek_in *in;\n+        struct fuse_lseek_out *out;\n+\n+        if (exp->uring_started) {\n+            in = in_buf;\n+            out = out_buf;\n+        } else {\n+            FuseQueue *q = opaque;\n+            in = FUSE_IN_OP_STRUCT_LEGACY(lseek, q);\n+            if (!in) {\n+                break;\n+            }\n+\n+            out = FUSE_OUT_OP_STRUCT_LEGACY(lseek, out_buf);\n+        }\n+\n+        ret = fuse_co_lseek(exp, out, in->offset, in->whence);\n         break;\n     }\n #endif\n@@ -1888,20 +1974,12 @@ fuse_co_process_request(FuseQueue *q, void *spillover_buf)\n         ret = -ENOSYS;\n     }\n\n-    /* Ignore errors from fuse_write*(), nothing we can do anyway */\n+    send_response(opaque, req_id, ret, out_data_buffer, out_buf);\n+\n     if (out_data_buffer) {\n-        assert(ret >= 0);\n-        fuse_write_buf_response(q->fuse_fd, req_id, out_hdr,\n-                                out_data_buffer, ret);\n         qemu_vfree(out_data_buffer);\n-    } else {\n-        fuse_write_response(q->fuse_fd, req_id, out_hdr,\n-                            ret < 0 ? ret : 0,\n-                            ret < 0 ? 0 : ret);\n     }\n\n-    qemu_vfree(spillover_buf);\n-\n #ifdef CONFIG_LINUX_IO_URING\n     if (unlikely(opcode == FUSE_INIT) && uring_initially_enabled) {\n         if (exp->is_uring && !exp->uring_started) {\n@@ -1910,7 +1988,8 @@ fuse_co_process_request(FuseQueue *q, void *spillover_buf)\n              * If io_uring mode was requested for this export but it has not\n              * been started yet, start it now.\n              */\n-            struct fuse_init_out *out = FUSE_OUT_OP_STRUCT(init, out_buf);\n+            struct fuse_init_out *out =\n+                FUSE_OUT_OP_STRUCT_LEGACY(init, out_buf);\n             fuse_uring_start(exp, out);\n         } else if (ret == -EOPNOTSUPP) {\n             /*\n@@ -1923,12 +2002,135 @@ fuse_co_process_request(FuseQueue *q, void *spillover_buf)\n     }\n #endif\n }\n+/* Helper to send response for legacy */\n+static void send_response_legacy(void *opaque, uint32_t req_id, int ret,\n+                                 const void *buf, void *out_buf)\n+{\n+    FuseQueue *q = (FuseQueue *)opaque;\n+    struct fuse_out_header *out_hdr = (struct fuse_out_header *)out_buf;\n+    if (buf) {\n+        assert(ret >= 0);\n+        fuse_write_buf_response(q->fuse_fd, req_id, out_hdr, buf, ret);\n+    } else {\n+        fuse_write_response(q->fuse_fd, req_id, out_hdr,\n+                            ret < 0 ? ret : 0,\n+                            ret < 0 ? 0 : ret);\n+    }\n+}\n+\n+static void coroutine_fn\n+fuse_co_process_request(FuseQueue *q, void *spillover_buf)\n+{\n+    FuseExport *exp = q->exp;\n+    uint32_t opcode;\n+    uint64_t req_id;\n+\n+    /*\n+     * Return buffer.  Must be large enough to hold all return headers, but does\n+     * not include space for data returned by read requests.\n+     */\n+    char out_buf[sizeof(struct fuse_out_header) +\n+        MAX_CONST(sizeof(struct fuse_init_out),\n+        MAX_CONST(sizeof(struct fuse_open_out),\n+        MAX_CONST(sizeof(struct fuse_attr_out),\n+        MAX_CONST(sizeof(struct fuse_write_out),\n+                  sizeof(struct fuse_lseek_out)))))] = {0};\n+\n+    /* Verify that out_buf is large enough for all output structures */\n+    QEMU_BUILD_BUG_ON(sizeof(struct fuse_out_header) +\n+        sizeof(struct fuse_init_out) > sizeof(out_buf));\n+    QEMU_BUILD_BUG_ON(sizeof(struct fuse_out_header) +\n+        sizeof(struct fuse_open_out) > sizeof(out_buf));\n+    QEMU_BUILD_BUG_ON(sizeof(struct fuse_out_header) +\n+        sizeof(struct fuse_attr_out) > sizeof(out_buf));\n+    QEMU_BUILD_BUG_ON(sizeof(struct fuse_out_header) +\n+        sizeof(struct fuse_write_out) > sizeof(out_buf));\n+#ifdef CONFIG_FUSE_LSEEK\n+    QEMU_BUILD_BUG_ON(sizeof(struct fuse_out_header) +\n+        sizeof(struct fuse_lseek_out) > sizeof(out_buf));\n+#endif\n+\n+    /* Limit scope to ensure pointer is no longer used after yielding */\n+    {\n+        const struct fuse_in_header *in_hdr =\n+            (const struct fuse_in_header *)q->request_buf;\n+\n+        opcode = in_hdr->opcode;\n+        req_id = in_hdr->unique;\n+    }\n+\n+    fuse_co_process_request_common(exp, opcode, req_id, NULL, spillover_buf,\n+                                   out_buf, send_response_legacy, q);\n+}\n\n #ifdef CONFIG_LINUX_IO_URING\n+static void fuse_uring_prep_sqe_commit(struct io_uring_sqe *sqe, void *opaque)\n+{\n+    FuseUringEnt *ent = opaque;\n+    struct fuse_uring_cmd_req *req = (void *)&sqe->cmd[0];\n+\n+    ent->last_cmd = FUSE_IO_URING_CMD_COMMIT_AND_FETCH;\n+\n+    fuse_uring_sqe_prepare(sqe, ent->rq->q, ent->last_cmd);\n+    fuse_uring_sqe_set_req_data(req, ent->rq->rqid, ent->req_commit_id);\n+}\n+\n+static void\n+fuse_uring_send_response(FuseUringEnt *ent, uint32_t req_id, int ret,\n+                         const void *out_data_buffer)\n+{\n+    FuseExport *exp = ent->rq->q->exp;\n+\n+    struct fuse_uring_req_header *rrh = &ent->req_header;\n+    struct fuse_out_header *out_header = (struct fuse_out_header *)&rrh->in_out;\n+    struct fuse_uring_ent_in_out *ent_in_out =\n+        (struct fuse_uring_ent_in_out *)&rrh->ring_ent_in_out;\n+\n+    /* FUSE_READ */\n+    if (out_data_buffer && ret > 0) {\n+        memcpy(ent->req_payload, out_data_buffer, ret);\n+    }\n+\n+    out_header->error  = ret < 0 ? ret : 0;\n+    out_header->unique = req_id;\n+    ent_in_out->payload_sz = ret > 0 ? ret : 0;\n+\n+    /* Commit and fetch a uring entry */\n+    blk_exp_ref(&exp->common);\n+    aio_add_sqe(fuse_uring_prep_sqe_commit, ent, &ent->fuse_cqe_handler);\n+}\n+\n+/* Helper to send response for uring */\n+static void send_response_uring(void *opaque, uint32_t req_id, int ret,\n+                                const void *out_data_buffer, void *payload)\n+{\n+    FuseUringEnt *ent = (FuseUringEnt *)opaque;\n+\n+    fuse_uring_send_response(ent, req_id, ret, out_data_buffer);\n+}\n+\n static void coroutine_fn fuse_uring_co_process_request(FuseUringEnt *ent)\n {\n-    /* TODO */\n-    (void)ent;\n+    FuseExport *exp = ent->rq->q->exp;\n+    struct fuse_uring_req_header *rrh = &ent->req_header;\n+    struct fuse_uring_ent_in_out *ent_in_out =\n+        (struct fuse_uring_ent_in_out *)&rrh->ring_ent_in_out;\n+    struct fuse_in_header *in_hdr =\n+        (struct fuse_in_header *)&rrh->in_out;\n+    uint32_t opcode = in_hdr->opcode;\n+    uint64_t req_id = in_hdr->unique;\n+\n+    ent->req_commit_id = ent_in_out->commit_id;\n+\n+    if (unlikely(ent->req_commit_id == 0)) {\n+        error_report(\"If this happens kernel will not find the response - \"\n+            \"it will be stuck forever - better to abort immediately.\");\n+        fuse_export_halt(exp);\n+        return;\n+    }\n+\n+    fuse_co_process_request_common(exp, opcode, req_id, &rrh->op_in,\n+        NULL, ent->req_payload, send_response_uring, ent);\n }\n #endif /* CONFIG_LINUX_IO_URING */\n\n",
    "prefixes": [
        "v4",
        "4/7"
    ]
}