Adjust internal fallocate interface to changed io_uring interface

with 6abc7c970dd5be381e588b9d0234c385a5a6d0d7 in liburing,
io_uring_prep_fallocate() arguments were (rightly) changed
from off_t to __u64.

Reflect this change. Also note that our struct fellow_io_discard
already used uint64_t.

Reported by Flexelint

src/fellow_io_backend.h

@@ -54,7 +54,7 @@ int fellow_io_write_async_enq(fellow_ioctx_t *ctx,
 int fellow_io_read_async_enq(fellow_ioctx_t *ctx,
     uint64_t info, void *buf, size_t bytes, off_t off);
 int fellow_io_fallocate_enq(fellow_ioctx_t *ctxp, uint64_t info,
-    int mode, off_t offset, off_t len);
+    int mode, uint64_t offset, uint64_t len);
 unsigned fellow_io_blkdiscard_enq(fellow_ioctx_t *ctxp, uint64_t info,
     const struct fellow_io_discard *discards, unsigned n);
 

src/fellow_io_threads.c

@@ -303,7 +303,7 @@ fellow_io_write_async_enq(fellow_ioctx_t *ctxp,
 
 int
 fellow_io_fallocate_enq(fellow_ioctx_t *ctxp, uint64_t info,
-    int mode, off_t offset, off_t len)
+    int mode, uint64_t offset, uint64_t len)
 {
 	struct fellow_io_thread_r *req;
 	struct fellow_io_thread *ctx;
@@ -318,7 +318,7 @@ fellow_io_fallocate_enq(fellow_ioctx_t *ctxp, uint64_t info,
 	req->cmd = FIOT_FALLOCATE;
 	req->mode = mode;
 	req->bytes = (size_t)len;
-	req->off = offset;
+	req->off = (off_t)offset;
 	req->status.info = info;
 
 	AZ(ctx->taskrun(fellow_io_thread_task, req,

src/fellow_io_uring.c

@@ -471,7 +471,7 @@ fellow_io_write_async_enq(fellow_ioctx_t *ctxp,
 
 int
 fellow_io_fallocate_enq(fellow_ioctx_t *ctxp, uint64_t info,
-    int mode, off_t offset, off_t len)
+    int mode, uint64_t offset, uint64_t len)
 {
 	struct fellow_io_uring *ctx;
 	struct io_uring_sqe *sqe;

src/fellow_log.c

@@ -1659,7 +1659,7 @@ fellow_io_regions_discard(struct fellow_fd *ffd, void *ioctx,
 			r = fellow_io_fallocate_enq(ioctx,
 			    faio_ptr_info(FAIOT_DISCARD, NULL),
 			    FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
-			    (off_t)todo->offset, (off_t)todo->len);
+			    todo->offset, todo->len);
 			if (r) {
 				todo++;
 				n--;