From patchwork Fri Jun 19 14:32:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 224062 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 0ADF3C433DF for ; Fri, 19 Jun 2020 15:27:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7A7521919 for ; Fri, 19 Jun 2020 15:27:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592580439; bh=UYYNl0Yb/dq/K1p1LK/ZDi5h3/DWZcAP6Qa7A1d8NYA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YgWxzM5O0v7rwb/UGj2lNNEXYUr+0py/JbLyhs00cmoPh+UmuGqj0BZQYboQL0nt4 Br/lmr8WX9OC1pLUreIDINb6/1qACvtBJ/6xgJMYePX3xC4hXVebZdY1H0p3P2ndVR nfeXDP8BW1mpCcsdduHIn8Pi9RVJHA915uOwWvTc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393534AbgFSP1T (ORCPT ); Fri, 19 Jun 2020 11:27:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:59022 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390810AbgFSP1S (ORCPT ); Fri, 19 Jun 2020 11:27:18 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8768C2186A; Fri, 19 Jun 2020 15:27:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592580437; bh=UYYNl0Yb/dq/K1p1LK/ZDi5h3/DWZcAP6Qa7A1d8NYA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=z2TYBrP1KT+Aj+cvHK58xdlZEeBu+YTHwPgi5N3+zeDP6b0SLUdg+46fUC0u6yWQo X66YEg0oxtZ4A82kKNNcZZRmneC+A6t297WQvdcuaVxTbJYFoc8rX/m0oP5ZVFVQZ8 RKNg/IePPcRXC275zVq2yH7bv/Em4T2EaUC9zc4c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nikolay Borisov , Josef Bacik , David Sterba , Sasha Levin Subject: [PATCH 5.7 218/376] btrfs: improve global reserve stealing logic Date: Fri, 19 Jun 2020 16:32:16 +0200 Message-Id: <20200619141720.647795004@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141710.350494719@linuxfoundation.org> References: <20200619141710.350494719@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Josef Bacik [ Upstream commit 7f9fe614407692f670601a634621138233ac00d7 ] For unlink transactions and block group removal btrfs_start_transaction_fallback_global_rsv will first try to start an ordinary transaction and if it fails it will fall back to reserving the required amount by stealing from the global reserve. This is problematic because of all the same reasons we had with previous iterations of the ENOSPC handling, thundering herd. We get a bunch of failures all at once, everybody tries to allocate from the global reserve, some win and some lose, we get an ENSOPC. Fix this behavior by introducing BTRFS_RESERVE_FLUSH_ALL_STEAL. It's used to mark unlink reservation. To fix this we need to integrate this logic into the normal ENOSPC infrastructure. We still go through all of the normal flushing work, and at the moment we begin to fail all the tickets we try to satisfy any tickets that are allowed to steal by stealing from the global reserve. If this works we start the flushing system over again just like we would with a normal ticket satisfaction. This serializes our global reserve stealing, so we don't have the thundering herd problem. Reviewed-by: Nikolay Borisov Tested-by: Nikolay Borisov Signed-off-by: Josef Bacik Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/block-group.c | 2 +- fs/btrfs/ctree.h | 1 + fs/btrfs/inode.c | 2 +- fs/btrfs/space-info.c | 37 ++++++++++++++++++++++++++++++++++++- fs/btrfs/space-info.h | 1 + fs/btrfs/transaction.c | 42 +++++------------------------------------- fs/btrfs/transaction.h | 3 +-- 7 files changed, 46 insertions(+), 42 deletions(-) diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index 696f47103cfc..233c5663f233 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -1175,7 +1175,7 @@ struct btrfs_trans_handle *btrfs_start_trans_remove_block_group( free_extent_map(em); return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root, - num_items, 1); + num_items); } /* diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 8aa7b9dac405..3510e33706c1 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2512,6 +2512,7 @@ enum btrfs_reserve_flush_enum { BTRFS_RESERVE_FLUSH_LIMIT, BTRFS_RESERVE_FLUSH_EVICT, BTRFS_RESERVE_FLUSH_ALL, + BTRFS_RESERVE_FLUSH_ALL_STEAL, }; enum btrfs_flush_state { diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 320d1062068d..259239b33370 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -3618,7 +3618,7 @@ static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir) * 1 for the inode ref * 1 for the inode */ - return btrfs_start_transaction_fallback_global_rsv(root, 5, 5); + return btrfs_start_transaction_fallback_global_rsv(root, 5); } static int btrfs_unlink(struct inode *dir, struct dentry *dentry) diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index 3c0e9999bfd7..eee6748c49e4 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -862,6 +862,34 @@ static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info, !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state)); } +static bool steal_from_global_rsv(struct btrfs_fs_info *fs_info, + struct btrfs_space_info *space_info, + struct reserve_ticket *ticket) +{ + struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; + u64 min_bytes; + + if (global_rsv->space_info != space_info) + return false; + + spin_lock(&global_rsv->lock); + min_bytes = div_factor(global_rsv->size, 5); + if (global_rsv->reserved < min_bytes + ticket->bytes) { + spin_unlock(&global_rsv->lock); + return false; + } + global_rsv->reserved -= ticket->bytes; + ticket->bytes = 0; + list_del_init(&ticket->list); + wake_up(&ticket->wait); + space_info->tickets_id++; + if (global_rsv->reserved < global_rsv->size) + global_rsv->full = 0; + spin_unlock(&global_rsv->lock); + + return true; +} + /* * maybe_fail_all_tickets - we've exhausted our flushing, start failing tickets * @fs_info - fs_info for this fs @@ -894,6 +922,10 @@ static bool maybe_fail_all_tickets(struct btrfs_fs_info *fs_info, ticket = list_first_entry(&space_info->tickets, struct reserve_ticket, list); + if (ticket->steal && + steal_from_global_rsv(fs_info, space_info, ticket)) + return true; + /* * may_commit_transaction will avoid committing the transaction * if it doesn't feel like the space reclaimed by the commit @@ -1110,6 +1142,7 @@ static int handle_reserve_ticket(struct btrfs_fs_info *fs_info, switch (flush) { case BTRFS_RESERVE_FLUSH_ALL: + case BTRFS_RESERVE_FLUSH_ALL_STEAL: wait_reserve_ticket(fs_info, space_info, ticket); break; case BTRFS_RESERVE_FLUSH_LIMIT: @@ -1209,7 +1242,9 @@ static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info, ticket.error = 0; space_info->reclaim_size += ticket.bytes; init_waitqueue_head(&ticket.wait); - if (flush == BTRFS_RESERVE_FLUSH_ALL) { + ticket.steal = (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL); + if (flush == BTRFS_RESERVE_FLUSH_ALL || + flush == BTRFS_RESERVE_FLUSH_ALL_STEAL) { list_add_tail(&ticket.list, &space_info->tickets); if (!space_info->flush) { space_info->flush = 1; diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h index 0a5001ef1481..c3c64019950a 100644 --- a/fs/btrfs/space-info.h +++ b/fs/btrfs/space-info.h @@ -78,6 +78,7 @@ struct btrfs_space_info { struct reserve_ticket { u64 bytes; int error; + bool steal; struct list_head list; wait_queue_head_t wait; }; diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 2d5498136e5e..b5da5d8342dc 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -563,7 +563,8 @@ start_transaction(struct btrfs_root *root, unsigned int num_items, * refill that amount for whatever is missing in the reserve. */ num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items); - if (delayed_refs_rsv->full == 0) { + if (flush == BTRFS_RESERVE_FLUSH_ALL && + delayed_refs_rsv->full == 0) { delayed_refs_bytes = num_bytes; num_bytes <<= 1; } @@ -699,43 +700,10 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( struct btrfs_root *root, - unsigned int num_items, - int min_factor) + unsigned int num_items) { - struct btrfs_fs_info *fs_info = root->fs_info; - struct btrfs_trans_handle *trans; - u64 num_bytes; - int ret; - - /* - * We have two callers: unlink and block group removal. The - * former should succeed even if we will temporarily exceed - * quota and the latter operates on the extent root so - * qgroup enforcement is ignored anyway. - */ - trans = start_transaction(root, num_items, TRANS_START, - BTRFS_RESERVE_FLUSH_ALL, false); - if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC) - return trans; - - trans = btrfs_start_transaction(root, 0); - if (IS_ERR(trans)) - return trans; - - num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items); - ret = btrfs_cond_migrate_bytes(fs_info, &fs_info->trans_block_rsv, - num_bytes, min_factor); - if (ret) { - btrfs_end_transaction(trans); - return ERR_PTR(ret); - } - - trans->block_rsv = &fs_info->trans_block_rsv; - trans->bytes_reserved = num_bytes; - trace_btrfs_space_reservation(fs_info, "transaction", - trans->transid, num_bytes, 1); - - return trans; + return start_transaction(root, num_items, TRANS_START, + BTRFS_RESERVE_FLUSH_ALL_STEAL, false); } struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root) diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index 31ae8d273065..bf102e64bfb2 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -193,8 +193,7 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, unsigned int num_items); struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv( struct btrfs_root *root, - unsigned int num_items, - int min_factor); + unsigned int num_items); struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root); struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root); struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root);