#include <fcntl.h> #include <unistd.h> #include <liburing.h> void io_uring_prep_linkat(struct io_uring_sqe *sqe, int olddirfd, const char *oldpath, int newdirfd, const char *newpath, int flags); void io_uring_prep_link(struct io_uring_sqe *sqe, const char *oldpath, const char *newpath, int flags);
The io_uring_prep_linkat(3) function prepares a linkat request. The submission queue entry sqe is setup to use the old directory file descriptor pointed to by olddirfd and old path pointed to by oldpath with the new directory file descriptor pointed to by newdirfd and the new path pointed to by newpath and using the specified flags in flags.
The io_uring_prep_link(3) function prepares a link request. The submission queue entry sqe is setup to use the old path pointed to by oldpath and the new path pointed to by newpath, both relative to the current working directory and using the specified flags in flags.
These functions prepare an async linkat(2) or link(2) request. See those man pages for details.
The CQE res field will contain the result of the operation. See the related man page for details on possible values. Note that where synchronous system calls will return -1 on failure and set errno to the actual error value, io_uring never uses errno. Instead it returns the negated errno directly in the CQE res field.
As with any request that passes in data in a struct, that data must remain valid until the request has been successfully submitted. It need not remain valid until completion. Once a request has been submitted, the in-kernel state is stable. Very early kernels (5.4 and earlier) required state to be stable until the completion occurred. Applications can test for this behavior by inspecting the IORING_FEAT_SUBMIT_STABLE flag passed back from io_uring_queue_init_params(3).
io_uring_get_sqe(3), io_uring_submit(3), linkat(2), link(2)
The man page io_uring_prep_link(3) is an alias of io_uring_prep_linkat(3).