From patchwork Fri Jan 3 15:02:26 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Harmstone X-Patchwork-Id: 13925653 Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 63BA41E00B4 for ; Fri, 3 Jan 2025 15:02:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.153.30 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735916570; cv=none; b=Rp1Wsw0B7yzHMcygMhf1lYeH94pQ6/QqfQR2CohVBM0jx9OYNqRYDao02r081WnPcgq25ogHL001rrdJOA+Fd4td970RZ8iFqWWB6PH7l+gNYbFtN3uA3RD4looDt+++9BTSc96yzQrLONXj5yweEKg5ML5WQ8wRrk5ryRqyhRg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735916570; c=relaxed/simple; bh=giMEFEEAFOP4LJMoc3A1BLAawFUvReuK96IV6T9xtmI=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=c6gD0jXMTA7VnPVSJjyyTHiK/AcLit6rQRHZZeGl2h/6k2ap9RtDc6PzvhtBhuxSSnhWPHfNZGMm5e0REeRj4mrOPNBBy82rxzH4AuOgzfk8yvAP4GR0IMSzBTHl88U3SgCEJDIQO7/YZDhnmSJUBvOlvai/oUAsZK0C8b7sZqc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fb.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b=o4yRC+xx; arc=none smtp.client-ip=67.231.153.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fb.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="o4yRC+xx" Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.18.1.2/8.18.1.2) with ESMTP id 503F0Vv5010820 for ; Fri, 3 Jan 2025 07:02:47 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=facebook; bh=b vHyemw4w4xwJUZezKNO3+boUFWVHef3Jyozxyi8FFc=; b=o4yRC+xx1SM455Uz+ HplsPnHr0F3DzGikPWVwx/vhi+7AU4hnAe3rZoLAYvk0utgM5TIDYx2InO0PILle W2iGQOfzqoOLi4A5/iPHC+s7qqVAjyg9JvYa8pGRjoo8oD5WTTom2YZyKI22TfC4 Oh7IvXQgIWW4/1k3Fg2Qnp6Wv8= Received: from mail.thefacebook.com ([163.114.134.16]) by m0001303.ppops.net (PPS) with ESMTPS id 43xgsmrf38-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 03 Jan 2025 07:02:47 -0800 (PST) Received: from twshared9216.15.frc2.facebook.com (2620:10d:c085:208::7cb7) by mail.thefacebook.com (2620:10d:c08b:78::2ac9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.1544.14; Fri, 3 Jan 2025 15:02:45 +0000 Received: by devbig276.nha1.facebook.com (Postfix, from userid 660015) id B39AAA24068D; Fri, 3 Jan 2025 15:02:34 +0000 (GMT) From: Mark Harmstone To: , CC: Mark Harmstone , Jens Axboe Subject: [PATCH 4/4] btrfs: don't read from userspace twice in btrfs_uring_encoded_read() Date: Fri, 3 Jan 2025 15:02:26 +0000 Message-ID: <20250103150233.2340306-5-maharmstone@fb.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250103150233.2340306-1-maharmstone@fb.com> References: <20250103150233.2340306-1-maharmstone@fb.com> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: BXB1E_AKvYLG8V-mu2kOSe9-vf_NFoYG X-Proofpoint-GUID: BXB1E_AKvYLG8V-mu2kOSe9-vf_NFoYG X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-05_03,2024-10-04_01,2024-09-30_01 If we return -EAGAIN the first time because we need to block, btrfs_uring_encoded_read() will get called twice. Take a copy of args, the iovs, and the iter the first time, as by the time we are called the second time these may have gone out of scope. Signed-off-by: Mark Harmstone Reported-by: Jens Axboe Fixes: 34310c442e17 ("btrfs: add io_uring command for encoded reads (ENCODED_READ ioctl)") --- fs/btrfs/ioctl.c | 125 ++++++++++++++++++++++++++--------------------- 1 file changed, 68 insertions(+), 57 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 7872de140489..eb7b330d7aab 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -4787,25 +4787,29 @@ static int btrfs_uring_read_extent(struct kiocb *iocb, struct iov_iter *iter, return ret; } +struct btrfs_uring_encoded_data { + struct btrfs_ioctl_encoded_io_args args; + struct iovec iovstack[UIO_FASTIOV]; + struct iovec *iov; + struct iov_iter iter; +}; + static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue_flags) { size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args, flags); size_t copy_end; - struct btrfs_ioctl_encoded_io_args args = { 0 }; int ret; u64 disk_bytenr, disk_io_size; struct file *file; struct btrfs_inode *inode; struct btrfs_fs_info *fs_info; struct extent_io_tree *io_tree; - struct iovec iovstack[UIO_FASTIOV]; - struct iovec *iov = iovstack; - struct iov_iter iter; loff_t pos; struct kiocb kiocb; struct extent_state *cached_state = NULL; u64 start, lockend; void __user *sqe_addr; + struct btrfs_uring_encoded_data *data = io_uring_cmd_get_async_data(cmd)->op_data; if (!capable(CAP_SYS_ADMIN)) { ret = -EPERM; @@ -4819,43 +4823,64 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue if (issue_flags & IO_URING_F_COMPAT) { #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT) - struct btrfs_ioctl_encoded_io_args_32 args32; - copy_end = offsetofend(struct btrfs_ioctl_encoded_io_args_32, flags); - if (copy_from_user(&args32, sqe_addr, copy_end)) { - ret = -EFAULT; - goto out_acct; - } - args.iov = compat_ptr(args32.iov); - args.iovcnt = args32.iovcnt; - args.offset = args32.offset; - args.flags = args32.flags; #else return -ENOTTY; #endif } else { copy_end = copy_end_kernel; - if (copy_from_user(&args, sqe_addr, copy_end)) { - ret = -EFAULT; + } + + if (!data) { + data = kzalloc(sizeof(*data), GFP_NOFS); + if (!data) { + ret = -ENOMEM; goto out_acct; } - } - if (args.flags != 0) - return -EINVAL; + io_uring_cmd_get_async_data(cmd)->op_data = data; - ret = import_iovec(ITER_DEST, args.iov, args.iovcnt, ARRAY_SIZE(iovstack), - &iov, &iter); - if (ret < 0) - goto out_acct; + if (issue_flags & IO_URING_F_COMPAT) { +#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT) + struct btrfs_ioctl_encoded_io_args_32 args32; - if (iov_iter_count(&iter) == 0) { - ret = 0; - goto out_free; + if (copy_from_user(&args32, sqe_addr, copy_end)) { + ret = -EFAULT; + goto out_acct; + } + + data->args.iov = compat_ptr(args32.iov); + data->args.iovcnt = args32.iovcnt; + data->args.offset = args32.offset; + data->args.flags = args32.flags; +#endif + } else { + if (copy_from_user(&data->args, sqe_addr, copy_end)) { + ret = -EFAULT; + goto out_acct; + } + } + + if (data->args.flags != 0) { + ret = -EINVAL; + goto out_acct; + } + + data->iov = data->iovstack; + ret = import_iovec(ITER_DEST, data->args.iov, data->args.iovcnt, + ARRAY_SIZE(data->iovstack), &data->iov, + &data->iter); + if (ret < 0) + goto out_acct; + + if (iov_iter_count(&data->iter) == 0) { + ret = 0; + goto out_free; + } } - pos = args.offset; - ret = rw_verify_area(READ, file, &pos, args.len); + pos = data->args.offset; + ret = rw_verify_area(READ, file, &pos, data->args.len); if (ret < 0) goto out_free; @@ -4868,15 +4893,16 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue start = ALIGN_DOWN(pos, fs_info->sectorsize); lockend = start + BTRFS_MAX_UNCOMPRESSED - 1; - ret = btrfs_encoded_read(&kiocb, &iter, &args, &cached_state, - &disk_bytenr, &disk_io_size); + ret = btrfs_encoded_read(&kiocb, &data->iter, &data->args, + &cached_state, &disk_bytenr, &disk_io_size); if (ret < 0 && ret != -EIOCBQUEUED) goto out_free; file_accessed(file); - if (copy_to_user(sqe_addr + copy_end, (const char *)&args + copy_end_kernel, - sizeof(args) - copy_end_kernel)) { + if (copy_to_user(sqe_addr + copy_end, + (const char *)&data->args + copy_end_kernel, + sizeof(data->args) - copy_end_kernel)) { if (ret == -EIOCBQUEUED) { unlock_extent(io_tree, start, lockend, &cached_state); btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); @@ -4886,39 +4912,24 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue } if (ret == -EIOCBQUEUED) { - u64 count; - - /* - * If we've optimized things by storing the iovecs on the stack, - * undo this. - */ - if (!iov) { - iov = kmemdup(iovstack, sizeof(struct iovec) * args.iovcnt, - GFP_NOFS); - if (!iov) { - unlock_extent(io_tree, start, lockend, &cached_state); - btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); - ret = -ENOMEM; - goto out_acct; - } - } - - count = min_t(u64, iov_iter_count(&iter), disk_io_size); + u64 count = min_t(u64, iov_iter_count(&data->iter), + disk_io_size); /* Match ioctl by not returning past EOF if uncompressed. */ - if (!args.compression) - count = min_t(u64, count, args.len); + if (!data->args.compression) + count = min_t(u64, count, data->args.len); - ret = btrfs_uring_read_extent(&kiocb, &iter, start, lockend, - cached_state, disk_bytenr, - disk_io_size, count, - args.compression, iov, cmd); + ret = btrfs_uring_read_extent(&kiocb, &data->iter, start, + lockend, cached_state, + disk_bytenr, disk_io_size, count, + data->args.compression, + data->iov, cmd); goto out_acct; } out_free: - kfree(iov); + kfree(data->iov); out_acct: if (ret > 0)