From patchwork Mon May 1 13:19:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 13227505 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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B3593C77B61 for ; Mon, 1 May 2023 13:19:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1682947164; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=KXIDMxkde2C9smMesK0jgfXOrCiHSyNhN+8LR7SB9GQ=; b=K1GsQwNiiK2Bp9xO+OuH2I6w/a1OStZFuCSbG6x/IVZ2Y1J05jy++A0Xq9Re8e/0J8TVUG orwkgNzSF86ji+KUTMnk8pvGe82wQYus/q67WK/krnJrXTpFu00JcJdSIUsxjOKlLX5j8+ YZhXE7TUif71Jih8RXiY0EFZTvbM3g0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-557-PUQifW7lOkeT74Ch5AS8sg-1; Mon, 01 May 2023 09:19:23 -0400 X-MC-Unique: PUQifW7lOkeT74Ch5AS8sg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6B752A0F396; Mon, 1 May 2023 13:19:21 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (unknown [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id 89444492C14; Mon, 1 May 2023 13:19:18 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 4D1EE19465B3; Mon, 1 May 2023 13:19:18 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id E54B81946587 for ; Mon, 1 May 2023 13:19:17 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 934AD63F40; Mon, 1 May 2023 13:19:17 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8398D63F2D; Mon, 1 May 2023 13:19:17 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id 341DJHNX009163; Mon, 1 May 2023 09:19:17 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id 341DJHHZ009160; Mon, 1 May 2023 09:19:17 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Mon, 1 May 2023 09:19:17 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Mike Snitzer In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (LRH 202 2017-01-01) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Subject: [dm-devel] [PATCH 1/3] dm-crypt: allocate compound pages if possible X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dm-devel@redhat.com Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com It was reported that allocating pages for the write buffer in dm-crypt causes measurable overhead [1]. This patch changes dm-crypt to allocate compound pages if they are available. If not, we fall back to the mempool. [1] https://listman.redhat.com/archives/dm-devel/2023-February/053284.html Signed-off-by: Mikulas Patocka --- drivers/md/dm-crypt.c | 50 +++++++++++++++++++++++++++++++++++--------------- 1 file changed, 35 insertions(+), 15 deletions(-) -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel Index: linux-2.6/drivers/md/dm-crypt.c =================================================================== --- linux-2.6.orig/drivers/md/dm-crypt.c +++ linux-2.6/drivers/md/dm-crypt.c @@ -1661,6 +1661,9 @@ static void crypt_free_buffer_pages(stru * In order to not degrade performance with excessive locking, we try * non-blocking allocations without a mutex first but on failure we fallback * to blocking allocations with a mutex. + * + * In order to reduce allocation overhead, we try to allocate compound pages in + * the first pass. If they are not available, we fall back to the mempool. */ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned int size) { @@ -1668,8 +1671,8 @@ static struct bio *crypt_alloc_buffer(st struct bio *clone; unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM; - unsigned int i, len, remaining_size; - struct page *page; + unsigned int remaining_size; + unsigned int order = MAX_ORDER - 1; retry: if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM)) @@ -1682,20 +1685,34 @@ retry: remaining_size = size; - for (i = 0; i < nr_iovecs; i++) { - page = mempool_alloc(&cc->page_pool, gfp_mask); - if (!page) { + while (remaining_size) { + struct page *pages; + unsigned size_to_add; + unsigned remaining_order = __fls((remaining_size + PAGE_SIZE - 1) >> PAGE_SHIFT); + order = min(order, remaining_order); + + while (order > 0) { + pages = alloc_pages(gfp_mask + | __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN | __GFP_COMP, + order); + if (likely(pages != NULL)) + goto have_pages; + order--; + } + + pages = mempool_alloc(&cc->page_pool, gfp_mask); + if (!pages) { crypt_free_buffer_pages(cc, clone); bio_put(clone); gfp_mask |= __GFP_DIRECT_RECLAIM; + order = 0; goto retry; } - len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size; - - bio_add_page(clone, page, len, 0); - - remaining_size -= len; +have_pages: + size_to_add = min((unsigned)PAGE_SIZE << order, remaining_size); + bio_add_page(clone, pages, size_to_add, 0); + remaining_size -= size_to_add; } /* Allocate space for integrity tags */ @@ -1713,12 +1730,15 @@ retry: static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone) { - struct bio_vec *bv; - struct bvec_iter_all iter_all; + struct folio_iter fi; - bio_for_each_segment_all(bv, clone, iter_all) { - BUG_ON(!bv->bv_page); - mempool_free(bv->bv_page, &cc->page_pool); + if (clone->bi_vcnt > 0) { /* bio_for_each_folio_all crashes with an empty bio */ + bio_for_each_folio_all(fi, clone) { + if (folio_test_large(fi.folio)) + folio_put(fi.folio); + else + mempool_free(&fi.folio->page, &cc->page_pool); + } } } From patchwork Mon May 1 13:19:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 13227506 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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8D90AC77B61 for ; Mon, 1 May 2023 13:19:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1682947192; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=pUGq7EpK9Ua6wILIyOGLMURnMsIruqJ7tb0+48iqf8s=; b=Qx9KNNWF8jHiAoUqsJjERez6nL7ZrJkBWjdr0rzdxyPcqrdrXvTvY9JTWm+4Kv5xtIlVLK GqudkMo0iBdsEmZDybS8URRlb0jfu+LlijVqmjdF35hnZ/KguT4cgq0JdxLCbaCUYXKHql ADqv7gnj/umsHfWQ8WP71zhUnAYkEu8= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-557-k5_pyuwNNbisq4pCXYfwrA-1; Mon, 01 May 2023 09:19:49 -0400 X-MC-Unique: k5_pyuwNNbisq4pCXYfwrA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BBDA01C08787; Mon, 1 May 2023 13:19:47 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (unknown [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id AAAAF40C6E69; Mon, 1 May 2023 13:19:47 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 9418C1946589; Mon, 1 May 2023 13:19:47 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 090ED1946587 for ; Mon, 1 May 2023 13:19:46 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id EB3932166B2B; Mon, 1 May 2023 13:19:45 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DBC812166B29; Mon, 1 May 2023 13:19:45 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id 341DJj32009214; Mon, 1 May 2023 09:19:45 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id 341DJjtZ009210; Mon, 1 May 2023 09:19:45 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Mon, 1 May 2023 09:19:45 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Mike Snitzer Message-ID: User-Agent: Alpine 2.21 (LRH 202 2017-01-01) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Subject: [dm-devel] [PATCH 2/3] dm flakey: clone pages on write bio before corrupting them X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dm-devel@redhat.com Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com dm-flakey has an option to corrupt write bios. It corrupts the memory that is being written. This can cause system crashes or security bugs - for example, if the user writes a shared library code with O_DIRECT flag to a dm-flakey device, it corrupts the memory for all users that have the shared library mapped. We fix this bug by cloning the bio and corrupting the clone rather than the original. We also drop the test for ZERO_PAGE(0) - it can't happen because we write the cloned pages. Signed-off-by: Mikulas Patocka --- drivers/md/dm-flakey.c | 108 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 97 insertions(+), 11 deletions(-) -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel Index: linux-2.6/drivers/md/dm-flakey.c =================================================================== --- linux-2.6.orig/drivers/md/dm-flakey.c +++ linux-2.6/drivers/md/dm-flakey.c @@ -322,11 +322,7 @@ static void corrupt_bio_data(struct bio */ bio_for_each_segment(bvec, bio, iter) { if (bio_iter_len(bio, iter) > corrupt_bio_byte) { - char *segment; - struct page *page = bio_iter_page(bio, iter); - if (unlikely(page == ZERO_PAGE(0))) - break; - segment = bvec_kmap_local(&bvec); + char *segment = bvec_kmap_local(&bvec); segment[corrupt_bio_byte] = fc->corrupt_bio_value; kunmap_local(segment); DMDEBUG("Corrupting data bio=%p by writing %u to byte %u " @@ -340,6 +336,92 @@ static void corrupt_bio_data(struct bio } } +static void clone_free(struct bio *clone) +{ + struct folio_iter fi; + + if (clone->bi_vcnt > 0) { /* bio_for_each_folio_all crashes with an empty bio */ + bio_for_each_folio_all(fi, clone) + folio_put(fi.folio); + } + + bio_uninit(clone); + kfree(clone); +} + +static void clone_endio(struct bio *clone) +{ + struct bio *bio = clone->bi_private; + bio->bi_status = clone->bi_status; + clone_free(clone); + bio_endio(bio); +} + +static struct bio *clone_bio(struct dm_target *ti, struct flakey_c *fc, struct bio *bio) +{ + struct bio *clone; + unsigned size, remaining_size, nr_iovecs, order; + struct bvec_iter iter = bio->bi_iter; + + if (unlikely(bio->bi_iter.bi_size > UIO_MAXIOV << PAGE_SHIFT)) + dm_accept_partial_bio(bio, UIO_MAXIOV << PAGE_SHIFT >> SECTOR_SHIFT); + + size = bio->bi_iter.bi_size; + nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; + + clone = bio_kmalloc(nr_iovecs, GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN); + if (!clone) + return NULL; + + bio_init(clone, fc->dev->bdev, bio->bi_inline_vecs, nr_iovecs, bio->bi_opf); + + clone->bi_iter.bi_sector = flakey_map_sector(ti, bio->bi_iter.bi_sector); + clone->bi_private = bio; + clone->bi_end_io = clone_endio; + + remaining_size = size; + + order = MAX_ORDER - 1; + while (remaining_size) { + struct page *pages; + unsigned size_to_add, to_copy; + unsigned char *virt; + unsigned remaining_order = __fls((remaining_size + PAGE_SIZE - 1) >> PAGE_SHIFT); + order = min(order, remaining_order); + +retry_alloc_pages: + pages = alloc_pages(GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN | __GFP_COMP, order); + if (unlikely(!pages)) { + if (order) { + order--; + goto retry_alloc_pages; + } + clone_free(clone); + return NULL; + } + size_to_add = min((unsigned)PAGE_SIZE << order, remaining_size); + + virt = page_to_virt(pages); + to_copy = size_to_add; + do { + struct bio_vec bvec = bvec_iter_bvec(bio->bi_io_vec, iter); + unsigned this_step = min(bvec.bv_len, to_copy); + void *map = bvec_kmap_local(&bvec); + memcpy(virt, map, this_step); + kunmap_local(map); + + bvec_iter_advance(bio->bi_io_vec, &iter, this_step); + to_copy -= this_step; + virt += this_step; + } while (to_copy); + + bio_add_page(clone, pages, size_to_add, 0); + remaining_size -= size_to_add; + } + + return clone; +} + static int flakey_map(struct dm_target *ti, struct bio *bio) { struct flakey_c *fc = ti->private; @@ -383,12 +465,16 @@ static int flakey_map(struct dm_target * /* * Corrupt matching writes. */ - if (fc->corrupt_bio_byte) { - if (fc->corrupt_bio_rw == WRITE) { - if (all_corrupt_bio_flags_match(bio, fc)) - corrupt_bio_data(bio, fc); - } - goto map_bio; + if (fc->corrupt_bio_byte && fc->corrupt_bio_rw == WRITE) { + if (all_corrupt_bio_flags_match(bio, fc)) { + struct bio *clone = clone_bio(ti, fc, bio); + if (clone) { + corrupt_bio_data(clone, fc); + submit_bio(clone); + return DM_MAPIO_SUBMITTED; + } + } + goto map_bio; } } From patchwork Mon May 1 13:20:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 13227508 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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A9FA6C77B73 for ; Mon, 1 May 2023 13:20:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1682947219; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=tIyKNVU5SZawWiVTWleT/f6ab+3FkplvojD3Usjm+ao=; b=FXcihzL5kn34otCXFFD3R751DJlj/F+Bc12sG3CZpxXrwMq2e6tmqkHhN9yZ1ElojFQCV/ 3LeX3EceYr9E+noFlKR+R5Jhgb8DgWci+I54WN5pc8Rk8XCX8XlUn/0lD6F5f/6HTINuAT iahM4ppt//DOXptVuwrPxdo0UAQVCFc= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-542-YvT0Md92MaertUvTR8wx4g-1; Mon, 01 May 2023 09:20:15 -0400 X-MC-Unique: YvT0Md92MaertUvTR8wx4g-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0D8531C05AB8; Mon, 1 May 2023 13:20:10 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (unknown [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id F14C7112132E; Mon, 1 May 2023 13:20:09 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id D2DC11946589; Mon, 1 May 2023 13:20:09 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 43BA91946587 for ; Mon, 1 May 2023 13:20:08 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 3088F2027046; Mon, 1 May 2023 13:20:08 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 236EA2027043; Mon, 1 May 2023 13:20:08 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id 341DK8kI009351; Mon, 1 May 2023 09:20:08 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id 341DK8R9009347; Mon, 1 May 2023 09:20:08 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Mon, 1 May 2023 09:20:08 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Mike Snitzer Message-ID: User-Agent: Alpine 2.21 (LRH 202 2017-01-01) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Subject: [dm-devel] [PATCH 3/3] dm flakey: introduce the random_read_corrupt and random_write_corrupt options X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dm-devel@redhat.com Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com The random_read_corrupt and random_write_corrupt options corrupt random byte in a bio with a given probability. The corruptions only happen in the "down" interval. Signed-off-by: Mikulas Patocka --- Documentation/admin-guide/device-mapper/dm-flakey.rst | 10 + drivers/md/dm-flakey.c | 118 ++++++++++++++---- 2 files changed, 108 insertions(+), 20 deletions(-) -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel Index: linux-2.6/drivers/md/dm-flakey.c =================================================================== --- linux-2.6.orig/drivers/md/dm-flakey.c +++ linux-2.6/drivers/md/dm-flakey.c @@ -16,6 +16,8 @@ #define DM_MSG_PREFIX "flakey" +#define PROBABILITY_BASE 1000000000 + #define all_corrupt_bio_flags_match(bio, fc) \ (((bio)->bi_opf & (fc)->corrupt_bio_flags) == (fc)->corrupt_bio_flags) @@ -34,6 +36,8 @@ struct flakey_c { unsigned int corrupt_bio_rw; unsigned int corrupt_bio_value; blk_opf_t corrupt_bio_flags; + unsigned int random_read_corrupt; + unsigned int random_write_corrupt; }; enum feature_flag_bits { @@ -54,10 +58,11 @@ static int parse_features(struct dm_arg_ const char *arg_name; static const struct dm_arg _args[] = { - {0, 7, "Invalid number of feature args"}, + {0, 11, "Invalid number of feature args"}, {1, UINT_MAX, "Invalid corrupt bio byte"}, {0, 255, "Invalid corrupt value to write into bio byte (0-255)"}, {0, UINT_MAX, "Invalid corrupt bio flags mask"}, + {0, PROBABILITY_BASE, "Invalid random corrupt argument"}, }; /* No feature arguments supplied. */ @@ -170,6 +175,32 @@ static int parse_features(struct dm_arg_ continue; } + if (!strcasecmp(arg_name, "random_read_corrupt")) { + if (!argc) { + ti->error = "Feature random_read_corrupt requires a parameter"; + return -EINVAL; + } + r = dm_read_arg(_args + 4, as, &fc->random_read_corrupt, &ti->error); + if (r) + return r; + argc--; + + continue; + } + + if (!strcasecmp(arg_name, "random_write_corrupt")) { + if (!argc) { + ti->error = "Feature random_write_corrupt requires a parameter"; + return -EINVAL; + } + r = dm_read_arg(_args + 4, as, &fc->random_write_corrupt, &ti->error); + if (r) + return r; + argc--; + + continue; + } + ti->error = "Unrecognised flakey feature requested"; return -EINVAL; } @@ -184,7 +215,8 @@ static int parse_features(struct dm_arg_ } if (!fc->corrupt_bio_byte && !test_bit(ERROR_READS, &fc->flags) && - !test_bit(DROP_WRITES, &fc->flags) && !test_bit(ERROR_WRITES, &fc->flags)) { + !test_bit(DROP_WRITES, &fc->flags) && !test_bit(ERROR_WRITES, &fc->flags) && + !fc->random_read_corrupt && !fc->random_write_corrupt) { set_bit(ERROR_WRITES, &fc->flags); set_bit(ERROR_READS, &fc->flags); } @@ -306,28 +338,23 @@ static void flakey_map_bio(struct dm_tar bio->bi_iter.bi_sector = flakey_map_sector(ti, bio->bi_iter.bi_sector); } -static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc) +static void corrupt_bio_common(struct bio *bio, unsigned int corrupt_bio_byte, unsigned char corrupt_bio_value) { - unsigned int corrupt_bio_byte = fc->corrupt_bio_byte - 1; - struct bvec_iter iter; struct bio_vec bvec; - if (!bio_has_data(bio)) - return; - /* * Overwrite the Nth byte of the bio's data, on whichever page * it falls. */ bio_for_each_segment(bvec, bio, iter) { if (bio_iter_len(bio, iter) > corrupt_bio_byte) { - char *segment = bvec_kmap_local(&bvec); - segment[corrupt_bio_byte] = fc->corrupt_bio_value; + unsigned char *segment = bvec_kmap_local(&bvec); + segment[corrupt_bio_byte] = corrupt_bio_value; kunmap_local(segment); DMDEBUG("Corrupting data bio=%p by writing %u to byte %u " "(rw=%c bi_opf=%u bi_sector=%llu size=%u)\n", - bio, fc->corrupt_bio_value, fc->corrupt_bio_byte, + bio, corrupt_bio_value, corrupt_bio_byte, (bio_data_dir(bio) == WRITE) ? 'w' : 'r', bio->bi_opf, (unsigned long long)bio->bi_iter.bi_sector, bio->bi_iter.bi_size); break; @@ -336,6 +363,30 @@ static void corrupt_bio_data(struct bio } } +static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc) +{ + unsigned int corrupt_bio_byte = fc->corrupt_bio_byte - 1; + + if (!bio_has_data(bio)) + return; + + corrupt_bio_common(bio, corrupt_bio_byte, fc->corrupt_bio_value); +} + +static void corrupt_bio_random(struct bio *bio) +{ + unsigned int corrupt_byte; + unsigned char corrupt_value; + + if (!bio_has_data(bio)) + return; + + corrupt_byte = get_random_u32() % bio->bi_iter.bi_size; + corrupt_value = get_random_u8(); + + corrupt_bio_common(bio, corrupt_byte, corrupt_value); +} + static void clone_free(struct bio *clone) { struct folio_iter fi; @@ -436,6 +487,7 @@ static int flakey_map(struct dm_target * /* Are we alive ? */ elapsed = (jiffies - fc->start_time) / HZ; if (elapsed % (fc->up_interval + fc->down_interval) >= fc->up_interval) { + bool corrupt_fixed, corrupt_random; /* * Flag this bio as submitted while down. */ @@ -465,16 +517,28 @@ static int flakey_map(struct dm_target * /* * Corrupt matching writes. */ + corrupt_fixed = false; + corrupt_random = false; if (fc->corrupt_bio_byte && fc->corrupt_bio_rw == WRITE) { - if (all_corrupt_bio_flags_match(bio, fc)) { - struct bio *clone = clone_bio(ti, fc, bio); - if (clone) { + if (all_corrupt_bio_flags_match(bio, fc)) + corrupt_fixed = true; + } + if (fc->random_write_corrupt) { + u64 rnd = get_random_u64(); + u32 rem = do_div(rnd, PROBABILITY_BASE); + if (rem < fc->random_write_corrupt) + corrupt_random = true; + } + if (corrupt_fixed || corrupt_random) { + struct bio *clone = clone_bio(ti, fc, bio); + if (clone) { + if (corrupt_fixed) corrupt_bio_data(clone, fc); - submit_bio(clone); - return DM_MAPIO_SUBMITTED; - } - } - goto map_bio; + if (corrupt_random) + corrupt_bio_random(clone); + submit_bio(clone); + return DM_MAPIO_SUBMITTED; + } } } @@ -503,6 +567,12 @@ static int flakey_end_io(struct dm_targe corrupt_bio_data(bio, fc); } } + if (fc->random_read_corrupt) { + u64 rnd = get_random_u64(); + u32 rem = do_div(rnd, PROBABILITY_BASE); + if (rem < fc->random_read_corrupt) + corrupt_bio_random(bio); + } if (test_bit(ERROR_READS, &fc->flags)) { /* * Error read during the down_interval if drop_writes @@ -535,7 +605,10 @@ static void flakey_status(struct dm_targ error_reads = test_bit(ERROR_READS, &fc->flags); drop_writes = test_bit(DROP_WRITES, &fc->flags); error_writes = test_bit(ERROR_WRITES, &fc->flags); - DMEMIT(" %u", error_reads + drop_writes + error_writes + (fc->corrupt_bio_byte > 0) * 5); + DMEMIT(" %u", error_reads + drop_writes + error_writes + + (fc->corrupt_bio_byte > 0) * 5 + + (fc->random_read_corrupt > 0) * 2 + + (fc->random_write_corrupt > 0) * 2); if (error_reads) DMEMIT(" error_reads"); @@ -550,6 +623,11 @@ static void flakey_status(struct dm_targ (fc->corrupt_bio_rw == WRITE) ? 'w' : 'r', fc->corrupt_bio_value, fc->corrupt_bio_flags); + if (fc->random_read_corrupt > 0) + DMEMIT(" %u", fc->random_read_corrupt); + if (fc->random_write_corrupt > 0) + DMEMIT(" %u", fc->random_write_corrupt); + break; case STATUSTYPE_IMA: Index: linux-2.6/Documentation/admin-guide/device-mapper/dm-flakey.rst =================================================================== --- linux-2.6.orig/Documentation/admin-guide/device-mapper/dm-flakey.rst +++ linux-2.6/Documentation/admin-guide/device-mapper/dm-flakey.rst @@ -67,6 +67,16 @@ Optional feature parameters: Perform the replacement only if bio->bi_opf has all the selected flags set. + random_read_corrupt + During , replace random byte in a read bio + with a random value. probability is an integer between + 0 and 1000000000 meaning 0% to 100% probability of corruption. + + random_write_corrupt + During , replace random byte in a write bio + with a random value. probability is an integer between + 0 and 1000000000 meaning 0% to 100% probability of corruption. + Examples: Replaces the 32nd byte of READ bios with the value 1::