From patchwork Thu Aug 12 08:41:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12432879 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18F5DC4338F for ; Thu, 12 Aug 2021 08:43:34 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8415860C3E for ; Thu, 12 Aug 2021 08:43:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8415860C3E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:37586 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mE6JG-0007P1-AY for qemu-devel@archiver.kernel.org; Thu, 12 Aug 2021 04:43:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35598) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mE6Hr-0004gQ-Ly for qemu-devel@nongnu.org; Thu, 12 Aug 2021 04:42:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:58273) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mE6Hn-0004fj-B6 for qemu-devel@nongnu.org; Thu, 12 Aug 2021 04:42:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628757717; h=from:from: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; bh=jBFBtbTLctx7RvR+a/of9f/yG22h3JtdlUpU+3KGcSk=; b=TR9NR8yp5CEuSIDUGPaCCvPwgdt1E9ZT6/EGCl51nTe++HtMwxS6opwbQFim8deXVKBgWQ SdKjYXVuxl2+z5+2TS6/KyLnB1YOF0d/G0ZeayKX7XPUYgKS+A0mFHppqnMwP5vj08NkhX QqNaFyicitkr3ZrEW1dinZ1jOrFA3AM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-366-nHOBMSHAMd2TWrBV1msBtA-1; Thu, 12 Aug 2021 04:41:53 -0400 X-MC-Unique: nHOBMSHAMd2TWrBV1msBtA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CC93C760C0; Thu, 12 Aug 2021 08:41:52 +0000 (UTC) Received: from localhost (unknown [10.39.193.89]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7563610016FB; Thu, 12 Aug 2021 08:41:52 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PATCH v3 1/6] block: Drop BDS comment regarding bdrv_append() Date: Thu, 12 Aug 2021 10:41:43 +0200 Message-Id: <20210812084148.14458-2-hreitz@redhat.com> In-Reply-To: <20210812084148.14458-1-hreitz@redhat.com> References: <20210812084148.14458-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.7, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Hanna Reitz , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" There is a comment above the BDS definition stating care must be taken to consider handling newly added fields in bdrv_append(). Actually, this comment should have said "bdrv_swap()" as of 4ddc07cac (nine years ago), and in any case, bdrv_swap() was dropped in 8e419aefa (six years ago). So no such care is necessary anymore. Signed-off-by: Hanna Reitz Reviewed-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Kevin Wolf --- include/block/block_int.h | 6 ------ 1 file changed, 6 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index f1a54db0f8..12e5750fe8 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -839,12 +839,6 @@ struct BdrvChild { QLIST_ENTRY(BdrvChild) next_parent; }; -/* - * Note: the function bdrv_append() copies and swaps contents of - * BlockDriverStates, so if you add new fields to this struct, please - * inspect bdrv_append() to determine if the new fields need to be - * copied as well. - */ struct BlockDriverState { /* Protected by big QEMU lock or read-only after opening. No special * locking needed during I/O... From patchwork Thu Aug 12 08:41:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12432885 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48B70C4338F for ; Thu, 12 Aug 2021 08:44:16 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9AC5C60C3E for ; Thu, 12 Aug 2021 08:44:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 9AC5C60C3E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:39278 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mE6Jy-00005D-Kp for qemu-devel@archiver.kernel.org; Thu, 12 Aug 2021 04:44:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35614) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mE6Hs-0004gk-D3 for qemu-devel@nongnu.org; Thu, 12 Aug 2021 04:42:04 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:28633) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mE6Hp-0004hO-5u for qemu-devel@nongnu.org; Thu, 12 Aug 2021 04:42:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628757719; h=from:from: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; bh=7gkOTyAa9y1A2m2kyR9anUa1YwnNOJ7rfWB5mmiA2LQ=; b=SPwEOU7dlD0tmJf2vM4ODHlRk6R7xY4U6g0+VyAeDOTrxeiXrGXyzfMjYwDDq32iK88+yG P2T4fKlPcbVDiqk9Wbd77Rgy02dGklV3cVBiG9I1KtbMFktnO1Co+cT6D+JPIqfIkQt9x+ TXbq1ire6nlle5BzLJCU3iYNdKGC9Bs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-196-n-2KzTz8MaubU4z-qYyEQA-1; Thu, 12 Aug 2021 04:41:55 -0400 X-MC-Unique: n-2KzTz8MaubU4z-qYyEQA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F0BD487D542; Thu, 12 Aug 2021 08:41:54 +0000 (UTC) Received: from localhost (unknown [10.39.193.89]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6D7AD4536; Thu, 12 Aug 2021 08:41:54 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PATCH v3 2/6] block: block-status cache for data regions Date: Thu, 12 Aug 2021 10:41:44 +0200 Message-Id: <20210812084148.14458-3-hreitz@redhat.com> In-Reply-To: <20210812084148.14458-1-hreitz@redhat.com> References: <20210812084148.14458-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.7, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Hanna Reitz , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" As we have attempted before (https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg06451.html, "file-posix: Cache lseek result for data regions"; https://lists.nongnu.org/archive/html/qemu-block/2021-02/msg00934.html, "file-posix: Cache next hole"), this patch seeks to reduce the number of SEEK_DATA/HOLE operations the file-posix driver has to perform. The main difference is that this time it is implemented as part of the general block layer code. The problem we face is that on some filesystems or in some circumstances, SEEK_DATA/HOLE is unreasonably slow. Given the implementation is outside of qemu, there is little we can do about its performance. We have already introduced the want_zero parameter to bdrv_co_block_status() to reduce the number of SEEK_DATA/HOLE calls unless we really want zero information; but sometimes we do want that information, because for files that consist largely of zero areas, special-casing those areas can give large performance boosts. So the real problem is with files that consist largely of data, so that inquiring the block status does not gain us much performance, but where such an inquiry itself takes a lot of time. To address this, we want to cache data regions. Most of the time, when bad performance is reported, it is in places where the image is iterated over from start to end (qemu-img convert or the mirror job), so a simple yet effective solution is to cache only the current data region. (Note that only caching data regions but not zero regions means that returning false information from the cache is not catastrophic: Treating zeroes as data is fine. While we try to invalidate the cache on zero writes and discards, such incongruences may still occur when there are other processes writing to the image.) We only use the cache for nodes without children (i.e. protocol nodes), because that is where the problem is: Drivers that rely on block-status implementations outside of qemu (e.g. SEEK_DATA/HOLE). Resolves: https://gitlab.com/qemu-project/qemu/-/issues/307 Signed-off-by: Hanna Reitz Reviewed-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy --- include/block/block_int.h | 50 ++++++++++++++++++++++++ block.c | 80 +++++++++++++++++++++++++++++++++++++++ block/io.c | 65 +++++++++++++++++++++++++++++-- 3 files changed, 192 insertions(+), 3 deletions(-) diff --git a/include/block/block_int.h b/include/block/block_int.h index 12e5750fe8..437d746733 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -34,6 +34,7 @@ #include "qemu/hbitmap.h" #include "block/snapshot.h" #include "qemu/throttle.h" +#include "qemu/rcu.h" #define BLOCK_FLAG_LAZY_REFCOUNTS 8 @@ -839,6 +840,24 @@ struct BdrvChild { QLIST_ENTRY(BdrvChild) next_parent; }; +/* + * Allows bdrv_co_block_status() to cache one data region for a + * protocol node. + * + * @valid: Whether the cache is valid (should be accessed with atomic + * functions so this can be reset by RCU readers) + * @data_start: Offset where we know (or strongly assume) is data + * @data_end: Offset where the data region ends (which is not necessarily + * the start of a zeroed region) + */ +typedef struct BdrvBlockStatusCache { + struct rcu_head rcu; + + bool valid; + int64_t data_start; + int64_t data_end; +} BdrvBlockStatusCache; + struct BlockDriverState { /* Protected by big QEMU lock or read-only after opening. No special * locking needed during I/O... @@ -1004,6 +1023,11 @@ struct BlockDriverState { /* BdrvChild links to this node may never be frozen */ bool never_freeze; + + /* Lock for block-status cache RCU writers */ + CoMutex bsc_modify_lock; + /* Always non-NULL, but must only be dereferenced under an RCU read guard */ + BdrvBlockStatusCache *block_status_cache; }; struct BlockBackendRootState { @@ -1429,4 +1453,30 @@ static inline BlockDriverState *bdrv_primary_bs(BlockDriverState *bs) */ void bdrv_drain_all_end_quiesce(BlockDriverState *bs); +/** + * Check whether the given offset is in the cached block-status data + * region. + * + * If it is, and @pnum is not NULL, *pnum is set to + * `bsc.data_end - offset`, i.e. how many bytes, starting from + * @offset, are data (according to the cache). + * Otherwise, *pnum is not touched. + */ +bool bdrv_bsc_is_data(BlockDriverState *bs, int64_t offset, int64_t *pnum); + +/** + * If [offset, offset + bytes) overlaps with the currently cached + * block-status region, invalidate the cache. + * + * (To be used by I/O paths that cause data regions to be zero or + * holes.) + */ +void bdrv_bsc_invalidate_range(BlockDriverState *bs, + int64_t offset, int64_t bytes); + +/** + * Mark the range [offset, offset + bytes) as a data region. + */ +void bdrv_bsc_fill(BlockDriverState *bs, int64_t offset, int64_t bytes); + #endif /* BLOCK_INT_H */ diff --git a/block.c b/block.c index e97ce0b1c8..28b00d7239 100644 --- a/block.c +++ b/block.c @@ -49,6 +49,8 @@ #include "qemu/timer.h" #include "qemu/cutils.h" #include "qemu/id.h" +#include "qemu/range.h" +#include "qemu/rcu.h" #include "block/coroutines.h" #ifdef CONFIG_BSD @@ -401,6 +403,9 @@ BlockDriverState *bdrv_new(void) qemu_co_queue_init(&bs->flush_queue); + qemu_co_mutex_init(&bs->bsc_modify_lock); + bs->block_status_cache = g_new0(BdrvBlockStatusCache, 1); + for (i = 0; i < bdrv_drain_all_count; i++) { bdrv_drained_begin(bs); } @@ -4694,6 +4699,8 @@ static void bdrv_close(BlockDriverState *bs) bs->explicit_options = NULL; qobject_unref(bs->full_open_options); bs->full_open_options = NULL; + g_free(bs->block_status_cache); + bs->block_status_cache = NULL; bdrv_release_named_dirty_bitmaps(bs); assert(QLIST_EMPTY(&bs->dirty_bitmaps)); @@ -7653,3 +7660,76 @@ BlockDriverState *bdrv_backing_chain_next(BlockDriverState *bs) { return bdrv_skip_filters(bdrv_cow_bs(bdrv_skip_filters(bs))); } + +/** + * Check whether [offset, offset + bytes) overlaps with the cached + * block-status data region. + * + * If so, and @pnum is not NULL, set *pnum to `bsc.data_end - offset`, + * which is what bdrv_bsc_is_data()'s interface needs. + * Otherwise, *pnum is not touched. + */ +static bool bdrv_bsc_range_overlaps_locked(BlockDriverState *bs, + int64_t offset, int64_t bytes, + int64_t *pnum) +{ + BdrvBlockStatusCache *bsc = qatomic_rcu_read(&bs->block_status_cache); + bool overlaps; + + overlaps = + qatomic_read(&bsc->valid) && + ranges_overlap(offset, bytes, bsc->data_start, + bsc->data_end - bsc->data_start); + + if (overlaps && pnum) { + *pnum = bsc->data_end - offset; + } + + return overlaps; +} + +/** + * See block_int.h for this function's documentation. + */ +bool bdrv_bsc_is_data(BlockDriverState *bs, int64_t offset, int64_t *pnum) +{ + RCU_READ_LOCK_GUARD(); + + return bdrv_bsc_range_overlaps_locked(bs, offset, 1, pnum); +} + +/** + * See block_int.h for this function's documentation. + */ +void bdrv_bsc_invalidate_range(BlockDriverState *bs, + int64_t offset, int64_t bytes) +{ + RCU_READ_LOCK_GUARD(); + + if (bdrv_bsc_range_overlaps_locked(bs, offset, bytes, NULL)) { + qatomic_set(&bs->block_status_cache->valid, false); + } +} + +/** + * See block_int.h for this function's documentation. + */ +void bdrv_bsc_fill(BlockDriverState *bs, int64_t offset, int64_t bytes) +{ + BdrvBlockStatusCache *new_bsc = g_new(BdrvBlockStatusCache, 1); + BdrvBlockStatusCache *old_bsc; + + *new_bsc = (BdrvBlockStatusCache) { + .valid = true, + .data_start = offset, + .data_end = offset + bytes, + }; + + QEMU_LOCK_GUARD(&bs->bsc_modify_lock); + + old_bsc = qatomic_rcu_read(&bs->block_status_cache); + qatomic_rcu_set(&bs->block_status_cache, new_bsc); + if (old_bsc) { + g_free_rcu(old_bsc, rcu); + } +} diff --git a/block/io.c b/block/io.c index a19942718b..e62cdbda99 100644 --- a/block/io.c +++ b/block/io.c @@ -1883,6 +1883,9 @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, return -ENOTSUP; } + /* Invalidate the cached block-status data range if this write overlaps */ + bdrv_bsc_invalidate_range(bs, offset, bytes); + assert(alignment % bs->bl.request_alignment == 0); head = offset % alignment; tail = (offset + bytes) % alignment; @@ -2447,9 +2450,62 @@ static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs, aligned_bytes = ROUND_UP(offset + bytes, align) - aligned_offset; if (bs->drv->bdrv_co_block_status) { - ret = bs->drv->bdrv_co_block_status(bs, want_zero, aligned_offset, - aligned_bytes, pnum, &local_map, - &local_file); + /* + * Use the block-status cache only for protocol nodes: Format + * drivers are generally quick to inquire the status, but protocol + * drivers often need to get information from outside of qemu, so + * we do not have control over the actual implementation. There + * have been cases where inquiring the status took an unreasonably + * long time, and we can do nothing in qemu to fix it. + * This is especially problematic for images with large data areas, + * because finding the few holes in them and giving them special + * treatment does not gain much performance. Therefore, we try to + * cache the last-identified data region. + * + * Second, limiting ourselves to protocol nodes allows us to assume + * the block status for data regions to be DATA | OFFSET_VALID, and + * that the host offset is the same as the guest offset. + * + * Note that it is possible that external writers zero parts of + * the cached regions without the cache being invalidated, and so + * we may report zeroes as data. This is not catastrophic, + * however, because reporting zeroes as data is fine. + */ + if (QLIST_EMPTY(&bs->children) && + bdrv_bsc_is_data(bs, aligned_offset, pnum)) + { + ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; + local_file = bs; + local_map = aligned_offset; + } else { + ret = bs->drv->bdrv_co_block_status(bs, want_zero, aligned_offset, + aligned_bytes, pnum, &local_map, + &local_file); + + /* + * Note that checking QLIST_EMPTY(&bs->children) is also done when + * the cache is queried above. Technically, we do not need to check + * it here; the worst that can happen is that we fill the cache for + * non-protocol nodes, and then it is never used. However, filling + * the cache requires an RCU update, so double check here to avoid + * such an update if possible. + */ + if (ret == (BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID) && + QLIST_EMPTY(&bs->children)) + { + /* + * When a protocol driver reports BLOCK_OFFSET_VALID, the + * returned local_map value must be the same as the offset we + * have passed (aligned_offset). + * Assert this, because we follow this rule when reading from + * the cache (see the `local_map = aligned_offset` assignment + * above), and the result the cache delivers must be the same + * as the driver would deliver. + */ + assert(local_map == aligned_offset); + bdrv_bsc_fill(bs, aligned_offset, *pnum); + } + } } else { /* Default code for filters */ @@ -3002,6 +3058,9 @@ int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset, return 0; } + /* Invalidate the cached block-status data range if this discard overlaps */ + bdrv_bsc_invalidate_range(bs, offset, bytes); + /* Discard is advisory, but some devices track and coalesce * unaligned requests, so we must pass everything down rather than * round here. Still, most devices will just silently ignore From patchwork Thu Aug 12 08:41:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12432881 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E684C4338F for ; Thu, 12 Aug 2021 08:44:04 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CFBA76103A for ; Thu, 12 Aug 2021 08:44:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org CFBA76103A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:38300 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mE6Jm-0007rL-M2 for qemu-devel@archiver.kernel.org; Thu, 12 Aug 2021 04:44:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35574) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mE6Hr-0004fm-5c for qemu-devel@nongnu.org; Thu, 12 Aug 2021 04:42:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:46234) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mE6Hp-0004hT-62 for qemu-devel@nongnu.org; Thu, 12 Aug 2021 04:42:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628757719; h=from:from: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; bh=AJc/JbhYorjEy4i7jmhVfBMpq2Saco4d+IvoYw2Dqps=; b=TS9hSyGqlcTVLVrkbFjLDUvP48D+B8CAmFfGrh30Ew6Y0peUHOwK9YGsR3dcjwzrlUyTZz VSX0PDiNg/2WiRsJLQkKqSlbRUrl1Cv3XFM9wiS23Ry1QWti5g/pI4uVh5viyELmRjdJdi D/2YQGwKRUIQOsH38mLlYsAgXHnbRP8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-20-AubHUzSAOs6GytN2BhLrtg-1; Thu, 12 Aug 2021 04:41:57 -0400 X-MC-Unique: AubHUzSAOs6GytN2BhLrtg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E5FE7190B2A2; Thu, 12 Aug 2021 08:41:56 +0000 (UTC) Received: from localhost (unknown [10.39.193.89]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8CB9A4536; Thu, 12 Aug 2021 08:41:56 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PATCH v3 3/6] block: Clarify that @bytes is no limit on *pnum Date: Thu, 12 Aug 2021 10:41:45 +0200 Message-Id: <20210812084148.14458-4-hreitz@redhat.com> In-Reply-To: <20210812084148.14458-1-hreitz@redhat.com> References: <20210812084148.14458-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) DKIMWL_WL_HIGH=-0.7, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Hanna Reitz , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" .bdrv_co_block_status() implementations are free to return a *pnum that exceeds @bytes, because bdrv_co_block_status() in block/io.c will clamp *pnum as necessary. On the other hand, if drivers' implementations return values for *pnum that are as large as possible, our recently introduced block-status cache will become more effective. So, make a note in block_int.h that @bytes is no upper limit for *pnum. Suggested-by: Eric Blake Signed-off-by: Hanna Reitz Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake --- include/block/block_int.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/include/block/block_int.h b/include/block/block_int.h index 437d746733..5451f89b8d 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -348,6 +348,15 @@ struct BlockDriver { * clamped to bdrv_getlength() and aligned to request_alignment, * as well as non-NULL pnum, map, and file; in turn, the driver * must return an error or set pnum to an aligned non-zero value. + * + * Note that @bytes is just a hint on how big of a region the + * caller wants to inspect. It is not a limit on *pnum. + * Implementations are free to return larger values of *pnum if + * doing so does not incur a performance penalty. + * + * block/io.c's bdrv_co_block_status() will utilize an unclamped + * *pnum value for the block-status cache on protocol nodes, prior + * to clamping *pnum for return to its caller. */ int coroutine_fn (*bdrv_co_block_status)(BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum, From patchwork Thu Aug 12 08:41:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12432907 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F81FC4338F for ; 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Thu, 12 Aug 2021 08:41:58 +0000 (UTC) Received: from localhost (unknown [10.39.193.89]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8BC845C23A; Thu, 12 Aug 2021 08:41:58 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PATCH v3 4/6] block/file-posix: Do not force-cap *pnum Date: Thu, 12 Aug 2021 10:41:46 +0200 Message-Id: <20210812084148.14458-5-hreitz@redhat.com> In-Reply-To: <20210812084148.14458-1-hreitz@redhat.com> References: <20210812084148.14458-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.7, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Hanna Reitz , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" bdrv_co_block_status() does it for us, we do not need to do it here. The advantage of not capping *pnum is that bdrv_co_block_status() can cache larger data regions than requested by its caller. Signed-off-by: Hanna Reitz Reviewed-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Kevin Wolf --- block/file-posix.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index cb9bffe047..9f35e5631a 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -2744,7 +2744,8 @@ static int find_allocation(BlockDriverState *bs, off_t start, * the specified offset) that are known to be in the same * allocated/unallocated state. * - * 'bytes' is the max value 'pnum' should be set to. + * 'bytes' is a soft cap for 'pnum'. If the information is free, 'pnum' may + * well exceed it. */ static int coroutine_fn raw_co_block_status(BlockDriverState *bs, bool want_zero, @@ -2782,7 +2783,7 @@ static int coroutine_fn raw_co_block_status(BlockDriverState *bs, } else if (data == offset) { /* On a data extent, compute bytes to the end of the extent, * possibly including a partial sector at EOF. */ - *pnum = MIN(bytes, hole - offset); + *pnum = hole - offset; /* * We are not allowed to return partial sectors, though, so @@ -2801,7 +2802,7 @@ static int coroutine_fn raw_co_block_status(BlockDriverState *bs, } else { /* On a hole, compute bytes to the beginning of the next extent. */ assert(hole == offset); - *pnum = MIN(bytes, data - offset); + *pnum = data - offset; ret = BDRV_BLOCK_ZERO; } *map = offset; From patchwork Thu Aug 12 08:41:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12432909 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71CA5C4338F for ; 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Thu, 12 Aug 2021 08:42:01 +0000 (UTC) Received: from localhost (unknown [10.39.193.89]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AB9B960C9D; Thu, 12 Aug 2021 08:42:00 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PATCH v3 5/6] block/gluster: Do not force-cap *pnum Date: Thu, 12 Aug 2021 10:41:47 +0200 Message-Id: <20210812084148.14458-6-hreitz@redhat.com> In-Reply-To: <20210812084148.14458-1-hreitz@redhat.com> References: <20210812084148.14458-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.7, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Hanna Reitz , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" bdrv_co_block_status() does it for us, we do not need to do it here. The advantage of not capping *pnum is that bdrv_co_block_status() can cache larger data regions than requested by its caller. Signed-off-by: Hanna Reitz Reviewed-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Kevin Wolf --- block/gluster.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/block/gluster.c b/block/gluster.c index e8ee14c8e9..8ef7bb18d5 100644 --- a/block/gluster.c +++ b/block/gluster.c @@ -1461,7 +1461,8 @@ exit: * the specified offset) that are known to be in the same * allocated/unallocated state. * - * 'bytes' is the max value 'pnum' should be set to. + * 'bytes' is a soft cap for 'pnum'. If the information is free, 'pnum' may + * well exceed it. * * (Based on raw_co_block_status() from file-posix.c.) */ @@ -1500,12 +1501,12 @@ static int coroutine_fn qemu_gluster_co_block_status(BlockDriverState *bs, } else if (data == offset) { /* On a data extent, compute bytes to the end of the extent, * possibly including a partial sector at EOF. */ - *pnum = MIN(bytes, hole - offset); + *pnum = hole - offset; ret = BDRV_BLOCK_DATA; } else { /* On a hole, compute bytes to the beginning of the next extent. */ assert(hole == offset); - *pnum = MIN(bytes, data - offset); + *pnum = data - offset; ret = BDRV_BLOCK_ZERO; } From patchwork Thu Aug 12 08:41:48 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12432911 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1DDDC4338F for ; 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Thu, 12 Aug 2021 08:42:03 +0000 (UTC) Received: from localhost (unknown [10.39.193.89]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AB5F25D740; Thu, 12 Aug 2021 08:42:02 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PATCH v3 6/6] block/iscsi: Do not force-cap *pnum Date: Thu, 12 Aug 2021 10:41:48 +0200 Message-Id: <20210812084148.14458-7-hreitz@redhat.com> In-Reply-To: <20210812084148.14458-1-hreitz@redhat.com> References: <20210812084148.14458-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.7, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Hanna Reitz , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" bdrv_co_block_status() does it for us, we do not need to do it here. The advantage of not capping *pnum is that bdrv_co_block_status() can cache larger data regions than requested by its caller. Signed-off-by: Hanna Reitz Reviewed-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Kevin Wolf --- block/iscsi.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/block/iscsi.c b/block/iscsi.c index 4d2a416ce7..852384086b 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -781,9 +781,6 @@ retry: iscsi_allocmap_set_allocated(iscsilun, offset, *pnum); } - if (*pnum > bytes) { - *pnum = bytes; - } out_unlock: qemu_mutex_unlock(&iscsilun->mutex); g_free(iTask.err_str);