(These patches depend on IORING_OP_MKDIRAT going in first -- see the changelog entry for v2 below.) These patches add support for IORING_OP_GETDENTS, which is a new io_uring opcode that more or less does an lseek(sqe->fd, sqe->off, SEEK_SET) followed by a getdents64(sqe->fd, (void *)sqe->addr, sqe->len). A dumb test program which recursively scans through a directory tree and prints the names of all directories and files it encounters along the way is available here: https://krautbox.wantstofly.org/~buytenh/uringfind-v3.c Changes since v3 RFC: - Made locking in io_getdents() unconditional, as the prior optimization was racy. (Pointed out by Pavel Begunkov.) - Rebase onto for-5.13/io_uring as of 2021/03/12 plus a manually applied version of the mkdirat patch. Changes since v2 RFC: - Rebase onto io_uring-2021-02-17 plus a manually applied version of the mkdirat patch. The latter is needed because userland (liburing) has already merged the opcode for IORING_OP_MKDIRAT (in commit "io_uring.h: 5.12 pending kernel sync") while this opcode isn't in the kernel yet (as of io_uring-2021-02-17), and this means that this can't be merged until IORING_OP_MKDIRAT is merged. - Adapt to changes made in "io_uring: replace force_nonblock with flags" that are in io_uring-2021-02-17. Changes since v1 RFC: - Drop the trailing '64' from IORING_OP_GETDENTS64 (suggested by Matthew Wilcox). - Instead of requiring that sqe->off be zero, use this field to pass in a directory offset to start reading from. For the first IORING_OP_GETDENTS call on a directory, this can be set to zero, and for subsequent calls, it can be set to the ->d_off field of the last struct linux_dirent64 returned by the previous call. Lennert Buytenhek (2): readdir: split the core of getdents64(2) out into vfs_getdents() io_uring: add support for IORING_OP_GETDENTS fs/io_uring.c | 66 ++++++++++++++++++++++++++++++++++++++++++ fs/readdir.c | 25 ++++++++++----- include/linux/fs.h | 4 ++ include/uapi/linux/io_uring.h | 1 4 files changed, 88 insertions(+), 8 deletions(-)
