From patchwork Wed May 10 10:52:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dominique Martinet X-Patchwork-Id: 13236773 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53D20C7EE26 for ; Wed, 10 May 2023 10:53:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235731AbjEJKxe (ORCPT ); Wed, 10 May 2023 06:53:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236631AbjEJKxb (ORCPT ); Wed, 10 May 2023 06:53:31 -0400 Received: from nautica.notk.org (ipv6.notk.org [IPv6:2001:41d0:1:7a93::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E272D7AA4; Wed, 10 May 2023 03:53:24 -0700 (PDT) Received: by nautica.notk.org (Postfix, from userid 108) id 8F293C009; Wed, 10 May 2023 12:53:23 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1683716003; bh=6QxWGUx7JcbfJLzcgzoVTnfXsX0NRwgrGu+B7GzT3oE=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=frnSqCTSHQv1C0QPaHCsmLdJhmn6iL3fb13CmnPoQtm7Ig2HE3VU2kpyo25bcFB1z IxW7BCRfVG2/S+rFGNBnAbUjLoTgD53kauNfV0KfwXidvNOQLnFdcKE95Xrr36Yav5 zv3FljxHoZMetPkBdXQnTTpQdb+rblz+dhTE5Q+YUWjT216z5IbnK2Bz/oKRWNzJX6 qxWe1G28PTDGMtmetta44c2ggjlV1oTYIzdRRnjahwxNcg4gpugbIM55c8xOWX+3Xt A5JR851bXCyPusWrJ3jGHF2TMz+fbaAdJH68sSgvuKZdU8nPH/v1XYl/yDFVan4QPJ z0KR61BBTkMHQ== Received: from odin.codewreck.org (localhost [127.0.0.1]) by nautica.notk.org (Postfix) with ESMTPS id 2BDE3C01F; Wed, 10 May 2023 12:53:16 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1683716003; bh=6QxWGUx7JcbfJLzcgzoVTnfXsX0NRwgrGu+B7GzT3oE=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=frnSqCTSHQv1C0QPaHCsmLdJhmn6iL3fb13CmnPoQtm7Ig2HE3VU2kpyo25bcFB1z IxW7BCRfVG2/S+rFGNBnAbUjLoTgD53kauNfV0KfwXidvNOQLnFdcKE95Xrr36Yav5 zv3FljxHoZMetPkBdXQnTTpQdb+rblz+dhTE5Q+YUWjT216z5IbnK2Bz/oKRWNzJX6 qxWe1G28PTDGMtmetta44c2ggjlV1oTYIzdRRnjahwxNcg4gpugbIM55c8xOWX+3Xt A5JR851bXCyPusWrJ3jGHF2TMz+fbaAdJH68sSgvuKZdU8nPH/v1XYl/yDFVan4QPJ z0KR61BBTkMHQ== Received: from [127.0.0.2] (localhost [::1]) by odin.codewreck.org (OpenSMTPD) with ESMTP id a820605c; Wed, 10 May 2023 10:53:02 +0000 (UTC) From: Dominique Martinet Date: Wed, 10 May 2023 19:52:51 +0900 Subject: [PATCH v2 3/6] io_uring: add support for getdents MIME-Version: 1.0 Message-Id: <20230422-uring-getdents-v2-3-2db1e37dc55e@codewreck.org> References: <20230422-uring-getdents-v2-0-2db1e37dc55e@codewreck.org> In-Reply-To: <20230422-uring-getdents-v2-0-2db1e37dc55e@codewreck.org> To: Alexander Viro , Christian Brauner , Jens Axboe , Pavel Begunkov , Stefan Roesch Cc: Clay Harris , Dave Chinner , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, io-uring@vger.kernel.org, Dominique Martinet X-Mailer: b4 0.13-dev-f371f X-Developer-Signature: v=1; a=openpgp-sha256; l=5527; i=asmadeus@codewreck.org; h=from:subject:message-id; bh=lY9CKW6ZADkqYeJH4NCrnDklEklhKGsfq33VwRZEwdo=; b=owEBbQKS/ZANAwAIAatOm+xqmOZwAcsmYgBkW3eOC1zQrTHzBzXLLRmTJc07x9GKHD6rFw5kJ 2/VulrZy52JAjMEAAEIAB0WIQT8g9txgG5a3TOhiE6rTpvsapjmcAUCZFt3jgAKCRCrTpvsapjm cP3RD/9B1dAYjRkQDf7/mjiqhh4CCu0Zc0OYp3EAOvIKqhAyW0yjs9xCBXRRnxlwx//3BDdpPa2 wU33hVMl9a1fYNpCPX3Kx5ZUPSAmQSCi7ujIs4Pfwb3muf3if4fCQVyzX9HTmugtLmTXVh3Zdtr 2BZb2vYMh469TNQefGbbJ1JSQIZzNpz7QBHL0wbizxuYKTo2QN8lfkKmDS1b01MiEBppy8BUYn4 YAR85UYr2U/SIOrg7kV8a1gDsC9IeFe87EP0GRbLyIKPAJfD/sLUN3rI6i8K6JN5EA7f9SgbRI2 KivEW9h47VAAWUZxEXkBU/1s0uxyhZVtjPeRnttqaCbQkCU2b7MEObdkti2AyyTHVfpQhWpYOyb rNCl1kLVVpeYd6JHiq06rzgf+Rom8xoYzZMFujFu401izGz1Szbz/3sh3OhrihOGwWmQjdauc1/ K1M4aLEjbCvTmXBS4CHEeoLglEBQmnB8QCPpGmHLzLVB0NJmR1PIlyZAaYKREesnON5h1MZY3P4 6slhYtaE3U5sBVT4h3j51oJZNRmW7s2g0E/eOcHSBjn4CdfQaloK/9zVC9D8knUUVoGC1ucsNts LoECZ7ctTtQNywACGHbMQwIYTlcnBx4o2KHcbNEV59r2OyqUz1BKtpxHeaA+5F1ORZN0XZO79K/ zsLgsMyj0lwBebg== X-Developer-Key: i=asmadeus@codewreck.org; a=openpgp; fpr=B894379F662089525B3FB1B9333F1F391BBBB00A Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org This add support for getdents64 to io_uring, acting exactly like the syscall: the directory is iterated from it's current's position as stored in the file struct, and the file's position is updated exactly as if getdents64 had been called. Additionally, since io_uring has no way of issuing a seek, a flag IORING_GETDENTS_REWIND has been added that will seek to the start of the directory like rewinddir(3) for users that might require such a thing. This will act exactly as if seek then getdents64 have been called sequentially with no atomicity guarantee: if this wasn't clear it is the responsibility of the caller to not use getdents multiple time on a single file in parallel if they want useful results, as is currently the case when using the syscall from multiple threads. For filesystems that support NOWAIT in iterate_shared(), try to use it first; if a user already knows the filesystem they use do not support nowait they can force async through IOSQE_ASYNC in the sqe flags, avoiding the need to bounce back through a useless EAGAIN return. (Note we already do that in prep if rewind is requested) Signed-off-by: Dominique Martinet --- include/uapi/linux/io_uring.h | 7 ++++++ io_uring/fs.c | 57 +++++++++++++++++++++++++++++++++++++++++++ io_uring/fs.h | 3 +++ io_uring/opdef.c | 8 ++++++ 4 files changed, 75 insertions(+) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 0716cb17e436..35d0de18d893 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -65,6 +65,7 @@ struct io_uring_sqe { __u32 xattr_flags; __u32 msg_ring_flags; __u32 uring_cmd_flags; + __u32 getdents_flags; }; __u64 user_data; /* data to be passed back at completion time */ /* pack this to avoid bogus arm OABI complaints */ @@ -223,6 +224,7 @@ enum io_uring_op { IORING_OP_URING_CMD, IORING_OP_SEND_ZC, IORING_OP_SENDMSG_ZC, + IORING_OP_GETDENTS, /* this goes last, obviously */ IORING_OP_LAST, @@ -259,6 +261,11 @@ enum io_uring_op { */ #define SPLICE_F_FD_IN_FIXED (1U << 31) /* the last bit of __u32 */ +/* + * sqe->getdents_flags + */ +#define IORING_GETDENTS_REWIND (1U << 0) + /* * POLL_ADD flags. Note that since sqe->poll_events is the flag space, the * command flags for POLL_ADD are stored in sqe->len. diff --git a/io_uring/fs.c b/io_uring/fs.c index f6a69a549fd4..b15ec81c1ed2 100644 --- a/io_uring/fs.c +++ b/io_uring/fs.c @@ -47,6 +47,13 @@ struct io_link { int flags; }; +struct io_getdents { + struct file *file; + struct linux_dirent64 __user *dirent; + unsigned int count; + int flags; +}; + int io_renameat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_rename *ren = io_kiocb_to_cmd(req, struct io_rename); @@ -291,3 +298,53 @@ void io_link_cleanup(struct io_kiocb *req) putname(sl->oldpath); putname(sl->newpath); } + +int io_getdents_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_getdents *gd = io_kiocb_to_cmd(req, struct io_getdents); + + if (READ_ONCE(sqe->off) != 0) + return -EINVAL; + + gd->dirent = u64_to_user_ptr(READ_ONCE(sqe->addr)); + gd->count = READ_ONCE(sqe->len); + gd->flags = READ_ONCE(sqe->getdents_flags); + if (gd->flags & ~IORING_GETDENTS_REWIND) + return -EINVAL; + /* rewind cannot be nowait */ + if (gd->flags & IORING_GETDENTS_REWIND) + req->flags |= REQ_F_FORCE_ASYNC; + + return 0; +} + +int io_getdents(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_getdents *gd = io_kiocb_to_cmd(req, struct io_getdents); + unsigned long getdents_flags = 0; + int ret; + + if (issue_flags & IO_URING_F_NONBLOCK) { + if (!(req->file->f_mode & FMODE_NOWAIT)) + return -EAGAIN; + + getdents_flags = DIR_CONTEXT_F_NOWAIT; + } + if ((gd->flags & IORING_GETDENTS_REWIND)) { + WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK); + + ret = vfs_llseek(req->file, 0, SEEK_SET); + if (ret < 0) + goto out; + } + + ret = vfs_getdents(req->file, gd->dirent, gd->count, getdents_flags); +out: + if (ret == -EAGAIN && + (issue_flags & IO_URING_F_NONBLOCK)) + return -EAGAIN; + + io_req_set_res(req, ret, 0); + return 0; +} + diff --git a/io_uring/fs.h b/io_uring/fs.h index 0bb5efe3d6bb..f83a6f3a678d 100644 --- a/io_uring/fs.h +++ b/io_uring/fs.h @@ -18,3 +18,6 @@ int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags); int io_linkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); int io_linkat(struct io_kiocb *req, unsigned int issue_flags); void io_link_cleanup(struct io_kiocb *req); + +int io_getdents_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_getdents(struct io_kiocb *req, unsigned int issue_flags); diff --git a/io_uring/opdef.c b/io_uring/opdef.c index cca7c5b55208..8f770c582ab3 100644 --- a/io_uring/opdef.c +++ b/io_uring/opdef.c @@ -428,6 +428,11 @@ const struct io_issue_def io_issue_defs[] = { .prep = io_eopnotsupp_prep, #endif }, + [IORING_OP_GETDENTS] = { + .needs_file = 1, + .prep = io_getdents_prep, + .issue = io_getdents, + }, }; @@ -648,6 +653,9 @@ const struct io_cold_def io_cold_defs[] = { .fail = io_sendrecv_fail, #endif }, + [IORING_OP_GETDENTS] = { + .name = "GETDENTS", + }, }; const char *io_uring_get_opcode(u8 opcode)