From patchwork Thu Oct 24 13:22:24 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 13848991 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (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 8B8191FBF65; Thu, 24 Oct 2024 13:25:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729776328; cv=none; b=Gto/EAe8Mz/XQTJVh2YKxYkNbqBXT41kRaNkE+cFR6CCsHj9GKNYZ7zJabhK4DMpvKvQrMphpWk10KH1JZa2kde4IjtRC09tpaTrVaIB8vf0hxcAhKk68JWCfII+lywTpwUcsElMFHA5/dbVqgsbnnotMieCZRVFHvcHA0WWfNE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729776328; c=relaxed/simple; bh=L+5WXtZxBV8aVRPEepS/zadXDDL+1k5ePjI582nYTyk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=cKiUDYuOGuU6Zuo2w7n0b7jO/EP6Db8y4d9quw79avKRDf2izjDIK916qanF3wpRYv1em9x1vwWI06Qy28aCd6rKu0ZZelmAzAYr3Wd/jrhWrF/ISpgvaqsNy9/Tmp68ycj8mexnWuo7G9tmoQ9J10TWK/r0qyHt6ugkNYg1Npg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4XZ68w1Bfvz4f3nbY; Thu, 24 Oct 2024 21:25:04 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 6E78A1A0197; Thu, 24 Oct 2024 21:25:22 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgD3LMmxShpnmfz6Ew--.42902S15; Thu, 24 Oct 2024 21:25:21 +0800 (CST) From: Yu Kuai To: stable@vger.kernel.org, gregkh@linuxfoundation.org, harry.wentland@amd.com, sunpeng.li@amd.com, Rodrigo.Siqueira@amd.com, alexander.deucher@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com, airlied@gmail.com, daniel@ffwll.ch, viro@zeniv.linux.org.uk, brauner@kernel.org, Liam.Howlett@oracle.com, akpm@linux-foundation.org, hughd@google.com, willy@infradead.org, sashal@kernel.org, srinivasan.shanmugam@amd.com, chiahsuan.chung@amd.com, mingo@kernel.org, mgorman@techsingularity.net, yukuai3@huawei.com, chengming.zhou@linux.dev, zhangpeng.00@bytedance.com, chuck.lever@oracle.com Cc: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, maple-tree@lists.infradead.org, linux-mm@kvack.org, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com Subject: [PATCH 6.6 27/28] libfs: fix infinite directory reads for offset dir Date: Thu, 24 Oct 2024 21:22:24 +0800 Message-Id: <20241024132225.2271667-12-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20241024132225.2271667-1-yukuai1@huaweicloud.com> References: <20241024132009.2267260-1-yukuai1@huaweicloud.com> <20241024132225.2271667-1-yukuai1@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: gCh0CgD3LMmxShpnmfz6Ew--.42902S15 X-Coremail-Antispam: 1UD129KBjvJXoWxGF4DCw48XFykAF4fGryrtFb_yoWrKF1fpF ZxG3Z3tr1fW34jgr4vvF1DZryF93Z3Kw4rX3s5Ww15try2qws8Kas2yr1Y9a48tr95Cr13 ZF45Ka43Xr4UCr7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUmF14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_GcCE3s 1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1l e2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI 8IcVAFwI0_Jrv_JF1lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwAC jcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2Y2ka0x kIwI1lc7CjxVAaw2AFwI0_Wrv_ZF1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_ Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1V AY17CE14v26rWY6r4UJwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26ryj6F1UMIIF 0xvE2Ix0cI8IcVCY1x0267AKxVWxJr0_GcWlIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMI IF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_GcCE3sUvcSsGvfC2 KfnxnUUI43ZEXa7sR_3ku7UUUUU== X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ From: yangerkun commit 64a7ce76fb901bf9f9c36cf5d681328fc0fd4b5a upstream. After we switch tmpfs dir operations from simple_dir_operations to simple_offset_dir_operations, every rename happened will fill new dentry to dest dir's maple tree(&SHMEM_I(inode)->dir_offsets->mt) with a free key starting with octx->newx_offset, and then set newx_offset equals to free key + 1. This will lead to infinite readdir combine with rename happened at the same time, which fail generic/736 in xfstests(detail show as below). 1. create 5000 files(1 2 3...) under one dir 2. call readdir(man 3 readdir) once, and get one entry 3. rename(entry, "TEMPFILE"), then rename("TEMPFILE", entry) 4. loop 2~3, until readdir return nothing or we loop too many times(tmpfs break test with the second condition) We choose the same logic what commit 9b378f6ad48cf ("btrfs: fix infinite directory reads") to fix it, record the last_index when we open dir, and do not emit the entry which index >= last_index. The file->private_data now used in offset dir can use directly to do this, and we also update the last_index when we llseek the dir file. Fixes: a2e459555c5f ("shmem: stable directory offsets") Signed-off-by: yangerkun Link: https://lore.kernel.org/r/20240731043835.1828697-1-yangerkun@huawei.com Reviewed-by: Chuck Lever [brauner: only update last_index after seek when offset is zero like Jan suggested] Signed-off-by: Christian Brauner Signed-off-by: Yu Kuai --- fs/libfs.c | 35 ++++++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 11 deletions(-) diff --git a/fs/libfs.c b/fs/libfs.c index 98731178a3c1..fd5d30c798de 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -405,6 +405,14 @@ void simple_offset_destroy(struct offset_ctx *octx) mtree_destroy(&octx->mt); } +static int offset_dir_open(struct inode *inode, struct file *file) +{ + struct offset_ctx *ctx = inode->i_op->get_offset_ctx(inode); + + file->private_data = (void *)ctx->next_offset; + return 0; +} + /** * offset_dir_llseek - Advance the read position of a directory descriptor * @file: an open directory whose position is to be updated @@ -418,6 +426,9 @@ void simple_offset_destroy(struct offset_ctx *octx) */ static loff_t offset_dir_llseek(struct file *file, loff_t offset, int whence) { + struct inode *inode = file->f_inode; + struct offset_ctx *ctx = inode->i_op->get_offset_ctx(inode); + switch (whence) { case SEEK_CUR: offset += file->f_pos; @@ -431,7 +442,8 @@ static loff_t offset_dir_llseek(struct file *file, loff_t offset, int whence) } /* In this case, ->private_data is protected by f_pos_lock */ - file->private_data = NULL; + if (!offset) + file->private_data = (void *)ctx->next_offset; return vfs_setpos(file, offset, LONG_MAX); } @@ -462,7 +474,7 @@ static bool offset_dir_emit(struct dir_context *ctx, struct dentry *dentry) inode->i_ino, fs_umode_to_dtype(inode->i_mode)); } -static void *offset_iterate_dir(struct inode *inode, struct dir_context *ctx) +static void offset_iterate_dir(struct inode *inode, struct dir_context *ctx, long last_index) { struct offset_ctx *octx = inode->i_op->get_offset_ctx(inode); struct dentry *dentry; @@ -470,17 +482,21 @@ static void *offset_iterate_dir(struct inode *inode, struct dir_context *ctx) while (true) { dentry = offset_find_next(octx, ctx->pos); if (!dentry) - return ERR_PTR(-ENOENT); + return; + + if (dentry2offset(dentry) >= last_index) { + dput(dentry); + return; + } if (!offset_dir_emit(ctx, dentry)) { dput(dentry); - break; + return; } ctx->pos = dentry2offset(dentry) + 1; dput(dentry); } - return NULL; } /** @@ -507,22 +523,19 @@ static void *offset_iterate_dir(struct inode *inode, struct dir_context *ctx) static int offset_readdir(struct file *file, struct dir_context *ctx) { struct dentry *dir = file->f_path.dentry; + long last_index = (long)file->private_data; lockdep_assert_held(&d_inode(dir)->i_rwsem); if (!dir_emit_dots(file, ctx)) return 0; - /* In this case, ->private_data is protected by f_pos_lock */ - if (ctx->pos == DIR_OFFSET_MIN) - file->private_data = NULL; - else if (file->private_data == ERR_PTR(-ENOENT)) - return 0; - file->private_data = offset_iterate_dir(d_inode(dir), ctx); + offset_iterate_dir(d_inode(dir), ctx, last_index); return 0; } const struct file_operations simple_offset_dir_operations = { + .open = offset_dir_open, .llseek = offset_dir_llseek, .iterate_shared = offset_readdir, .read = generic_read_dir,