From patchwork Fri Jan 26 15:21:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Solomonik X-Patchwork-Id: 13532808 Received: from mail-wr1-f47.google.com (mail-wr1-f47.google.com [209.85.221.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A3AC91CF8F for ; Fri, 26 Jan 2024 15:21:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.47 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706282489; cv=none; b=eMQySW0X3PNyzynyb5tJMwyOAXepBJJmaw4MYkkqXAY1WjwAq7qDAHdvhPJCPc1ooTw6j6Rimnt73+zA0gpvFtixlGDRn+hntnxqQkjI4soU3G/YrHma5AIA+lBXLgMAjdTXMI7L1BOa06kmRs3/Wg+TOwi5HrJ+sfKcZQez1l4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706282489; c=relaxed/simple; bh=qu9MebIgXCK2oZVRQ/fDV8Vis8po6FRI8tt9Ym3zsAs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=VyzcxCtKTjcjP1IUQzJKPhGyTi/L/LdKusb0K4idQK+3EBpn1Z4lAgYrQbdK8+k69rS09ppgttFU/hTjJFG6kFagkjMZcM5efz3nuI1NAJoNO3IRvOgwr3rV5DiHEShKQUx3a7n55K2z2y4JR2uIwzhH0ucxezt4AEBLl4skabc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=IiXr4xkd; arc=none smtp.client-ip=209.85.221.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="IiXr4xkd" Received: by mail-wr1-f47.google.com with SMTP id ffacd0b85a97d-3392291b21bso703823f8f.1 for ; Fri, 26 Jan 2024 07:21:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1706282486; x=1706887286; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=l7tl3ZXXLaYuRPJhUtawqYNe/HCu8Nw7RTBC/JyeS3k=; b=IiXr4xkdbtuweJtooWHHMFlm3DPBYqtaO5u7jcLmb+C2z7u5T2u25RUfg2y6BZZ1vr zUQ96a9dan85P5Trgf3WfBqbyrPsK9PPnp0z9WEN9Lst5MZuuz2fj30abmRGMRC37KoI Gva7+xRoDof36v+5oBlRa4DqHb38YVavJcEElj9UmFxFtMsUJahWik588WSWkmee8heH 4x1A4rr0Ld4G3hvu13rBZI91r0I+UAILvuFkkTJ85uNq1sO07Wv72PHdIj3Sduq9Va3g EN0gh2c7J7yFPZpAlzCnWGi5sCRSITd4dhXZfsSFcZcwSOhBz/n3BZkhj4D40/MHhiKU jzbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706282486; x=1706887286; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=l7tl3ZXXLaYuRPJhUtawqYNe/HCu8Nw7RTBC/JyeS3k=; b=Kv3OeREr6ZxmQNJzEMoQjYtSVXDaypFADtEfM8wqWcVcEJ/7kVpgdnZ9IyJJYMOM07 RXjlRR/reEMxXBaNsfEelzD8Nb5sU24L77pCLVZt72NtwesG0+/KQ7qCLMfl+NseIs9u 9tisRxmdo5knT7tVOWT93tdM/A+SCka76NSryWBzuq8bBLbCiAmLbxabdriBBgrzBeh5 1ECiyiPmmSVYfzyXThyaCS2ks5rIHliiuPs4jq2l7/CfS+Wpc5n+l9XkvvFyN8xns9m7 zN2EK357MvLHTOO4yfdm8GxhHEVWYG5swrvlnFAu3jUdxdFx2LyPPJuVTL3J46bsDt/m zA+A== X-Gm-Message-State: AOJu0YyrZ7/CP0/IO5a8tY/MsDPVk3O1nv/O8Lq1+vvv2LhKq5jv2bLx WWk6Y1jhTBTxqEYhJoZOCzXkjABqTsTFx8IQM6lMYT/z0IHTuZeP X-Google-Smtp-Source: AGHT+IG5kJQbLIiAxfGfR+r6vyxl0rUemEezoqPUNHkgIgm7VojJ8MciSN5FpAzHqIS9eXmRi6sb9Q== X-Received: by 2002:a5d:4524:0:b0:333:4c30:dae4 with SMTP id j4-20020a5d4524000000b003334c30dae4mr985201wra.45.1706282485615; Fri, 26 Jan 2024 07:21:25 -0800 (PST) Received: from localhost.localdomain ([147.235.201.119]) by smtp.gmail.com with ESMTPSA id bn7-20020a056000060700b0033946c0f9e7sm1493914wrb.17.2024.01.26.07.21.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Jan 2024 07:21:25 -0800 (PST) From: Tony Solomonik To: Cc: willy@infradead.org, axboe@kernel.dk, linux-fsdevel@vger.kernel.org, brauner@kernel.org, Tony Solomonik Subject: [PATCH v6 1/2] Add do_ftruncate that truncates a struct file Date: Fri, 26 Jan 2024 17:21:17 +0200 Message-Id: <20240126152118.14201-2-tony.solomonik@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240126152118.14201-1-tony.solomonik@gmail.com> References: <20240124083301.8661-1-tony.solomonik@gmail.com> <20240126152118.14201-1-tony.solomonik@gmail.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 do_sys_ftruncate receives a file descriptor, fgets the struct file, and finally actually truncates the file. do_ftruncate allows for passing in a file directly, with the caller already holding a reference to it. Signed-off-by: Tony Solomonik --- fs/internal.h | 1 + fs/open.c | 57 +++++++++++++++++++++++++++------------------------ 2 files changed, 31 insertions(+), 27 deletions(-) diff --git a/fs/internal.h b/fs/internal.h index 58e43341aebf..bb3df26a9a13 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -182,6 +182,7 @@ extern struct open_how build_open_how(int flags, umode_t mode); extern int build_open_flags(const struct open_how *how, struct open_flags *op); extern struct file *__close_fd_get_file(unsigned int fd); +long do_ftruncate(struct file *file, loff_t length, int small); long do_sys_ftruncate(unsigned int fd, loff_t length, int small); int chmod_common(const struct path *path, umode_t mode); int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group, diff --git a/fs/open.c b/fs/open.c index 02dc608d40d8..77db60c416db 100644 --- a/fs/open.c +++ b/fs/open.c @@ -154,49 +154,52 @@ COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length } #endif -long do_sys_ftruncate(unsigned int fd, loff_t length, int small) +long do_ftruncate(struct file *file, loff_t length, int small) { struct inode *inode; struct dentry *dentry; + int error; + + dentry = file->f_path.dentry; + inode = dentry->d_inode; + if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) + return -EINVAL; + + /* Cannot ftruncate over 2^31 bytes without large file support */ + if (small && length > MAX_NON_LFS) + return -EINVAL; + + /* Check IS_APPEND on real upper inode */ + if (IS_APPEND(file_inode(file))) + return -EPERM; + sb_start_write(inode->i_sb); + error = security_file_truncate(file); + if (!error) + error = do_truncate(file_mnt_idmap(file), dentry, length, + ATTR_MTIME | ATTR_CTIME, file); + sb_end_write(inode->i_sb); + + return error; +} + +long do_sys_ftruncate(unsigned int fd, loff_t length, int small) +{ struct fd f; int error; - error = -EINVAL; if (length < 0) - goto out; - error = -EBADF; + return -EINVAL; f = fdget(fd); if (!f.file) - goto out; + return -EBADF; /* explicitly opened as large or we are on 64-bit box */ if (f.file->f_flags & O_LARGEFILE) small = 0; - dentry = f.file->f_path.dentry; - inode = dentry->d_inode; - error = -EINVAL; - if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE)) - goto out_putf; + error = do_ftruncate(f.file, length, small); - error = -EINVAL; - /* Cannot ftruncate over 2^31 bytes without large file support */ - if (small && length > MAX_NON_LFS) - goto out_putf; - - error = -EPERM; - /* Check IS_APPEND on real upper inode */ - if (IS_APPEND(file_inode(f.file))) - goto out_putf; - sb_start_write(inode->i_sb); - error = security_file_truncate(f.file); - if (!error) - error = do_truncate(file_mnt_idmap(f.file), dentry, length, - ATTR_MTIME | ATTR_CTIME, f.file); - sb_end_write(inode->i_sb); -out_putf: fdput(f); -out: return error; }