From patchwork Wed Jul 24 06:34:51 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 11056147 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5A1091399 for ; Wed, 24 Jul 2019 06:35:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4A04C2876C for ; Wed, 24 Jul 2019 06:35:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3E02E28774; Wed, 24 Jul 2019 06:35:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8E3022876C for ; Wed, 24 Jul 2019 06:35:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726366AbfGXGfI (ORCPT ); Wed, 24 Jul 2019 02:35:08 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:40699 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725900AbfGXGfH (ORCPT ); Wed, 24 Jul 2019 02:35:07 -0400 Received: by mail-pf1-f193.google.com with SMTP id p184so20390599pfp.7; Tue, 23 Jul 2019 23:35:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=cpp8enRP/AyBuUHvXI1HE0/hiUBCzIH1tHBIJI0ZLGM=; b=eEhjl2XTfVNKPRymVgshe4gMFNYCo5airIp2GpJ8o4a/cKG5X74U7A39xR6hfUfGIL GTPvEPdcfIUwXziIFQDDwWoE1kIjw0/nU3rtGXAZVjn6ezvXEPZ3SsmmsdOnnyHGHHUv PdsBDq2QLVYG6kRJw9u4pHfz089dria0deFQQqU7xvyIybsaqkEgQ4+bw16qukZqkvE0 miskhW0IPYeY5EnqQOjE6ze3Vit3XPu4pv6+KpUAxLLbATIwZE3ltRyJsMmGP76yvjUc lR8lYjQ9NWk+1SbvipEs4tYB/RsESrypwgWAgSUwR8P3IOof0eXfBYQ+amwOg0aIqgvv JPzA== X-Gm-Message-State: APjAAAWe3yK5+qfgdaHp3+vWzVRM2TgGz63jVkYRplpxsLOiOKMk6Wju tBtm4yHrphgji0gw8ZT7w2w= X-Google-Smtp-Source: APXvYqzRM3gzuJsFTd9zhUs17lVSu8qoaw3WZdz56t+fQDnHYUgdyhYVVFD3y7xiLOEI8E1IKVEPRA== X-Received: by 2002:a65:620a:: with SMTP id d10mr34243196pgv.8.1563950106637; Tue, 23 Jul 2019 23:35:06 -0700 (PDT) Received: from 42.do-not-panic.com (42.do-not-panic.com. [157.230.128.187]) by smtp.gmail.com with ESMTPSA id d8sm42128986pgh.45.2019.07.23.23.35.00 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 23 Jul 2019 23:35:04 -0700 (PDT) Received: by 42.do-not-panic.com (Postfix, from userid 1000) id BB7EC40733; Wed, 24 Jul 2019 06:34:58 +0000 (UTC) From: Luis Chamberlain To: linux-xfs@vger.kernel.org, Alexander.Levin@microsoft.com Cc: gregkh@linuxfoundation.org, stable@vger.kernel.org, amir73il@gmail.com, "Darrick J. Wong" , Brian Foster , Luis Chamberlain Subject: [PATCH 6/6] xfs: always rejoin held resources during defer roll Date: Wed, 24 Jul 2019 06:34:51 +0000 Message-Id: <20190724063451.26190-7-mcgrof@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190724063451.26190-1-mcgrof@kernel.org> References: <20190724063451.26190-1-mcgrof@kernel.org> MIME-Version: 1.0 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: "Darrick J. Wong" commit 710d707d2fa9cf4c2aa9def129e71e99513466ea upstream. During testing of xfs/141 on a V4 filesystem, I observed some inconsistent behavior with regards to resources that are held (i.e. remain locked) across a defer roll. The transaction roll always gives the defer roll function a new transaction, even if committing the old transaction fails. However, the defer roll function only rejoins the held resources if the transaction commit succeedied. This means that callers of defer roll have to figure out whether the held resources are attached to the transaction being passed back. Worse yet, if the defer roll was part of a defer finish call, we have a third possibility: the defer finish could pass back a dirty transaction with dirty held resources and an error code. The only sane way to handle all of these scenarios is to require that the code that held the resource either cancel the transaction before unlocking and releasing the resources, or use functions that detach resources from a transaction properly (e.g. xfs_trans_brelse) if they need to drop the reference before committing or cancelling the transaction. In order to make this so, change the defer roll code to join held resources to the new transaction unconditionally and fix all the bhold callers to release the held buffers correctly. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster [mcgrof: fixes kz#204223 ] Signed-off-by: Luis Chamberlain --- fs/xfs/libxfs/xfs_attr.c | 35 ++++++++++++----------------------- fs/xfs/libxfs/xfs_attr.h | 2 +- fs/xfs/libxfs/xfs_defer.c | 14 +++++++++----- fs/xfs/xfs_dquot.c | 17 +++++++++-------- 4 files changed, 31 insertions(+), 37 deletions(-) diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c index 844ed87b1900..6410d3e00ce0 100644 --- a/fs/xfs/libxfs/xfs_attr.c +++ b/fs/xfs/libxfs/xfs_attr.c @@ -224,10 +224,10 @@ xfs_attr_try_sf_addname( */ int xfs_attr_set_args( - struct xfs_da_args *args, - struct xfs_buf **leaf_bp) + struct xfs_da_args *args) { struct xfs_inode *dp = args->dp; + struct xfs_buf *leaf_bp = NULL; int error; /* @@ -255,7 +255,7 @@ xfs_attr_set_args( * It won't fit in the shortform, transform to a leaf block. * GROT: another possible req'mt for a double-split btree op. */ - error = xfs_attr_shortform_to_leaf(args, leaf_bp); + error = xfs_attr_shortform_to_leaf(args, &leaf_bp); if (error) return error; @@ -263,23 +263,16 @@ xfs_attr_set_args( * Prevent the leaf buffer from being unlocked so that a * concurrent AIL push cannot grab the half-baked leaf * buffer and run into problems with the write verifier. + * Once we're done rolling the transaction we can release + * the hold and add the attr to the leaf. */ - xfs_trans_bhold(args->trans, *leaf_bp); - + xfs_trans_bhold(args->trans, leaf_bp); error = xfs_defer_finish(&args->trans); - if (error) - return error; - - /* - * Commit the leaf transformation. We'll need another - * (linked) transaction to add the new attribute to the - * leaf. - */ - error = xfs_trans_roll_inode(&args->trans, dp); - if (error) + xfs_trans_bhold_release(args->trans, leaf_bp); + if (error) { + xfs_trans_brelse(args->trans, leaf_bp); return error; - xfs_trans_bjoin(args->trans, *leaf_bp); - *leaf_bp = NULL; + } } if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) @@ -322,7 +315,6 @@ xfs_attr_set( int flags) { struct xfs_mount *mp = dp->i_mount; - struct xfs_buf *leaf_bp = NULL; struct xfs_da_args args; struct xfs_trans_res tres; int rsvd = (flags & ATTR_ROOT) != 0; @@ -381,9 +373,9 @@ xfs_attr_set( goto out_trans_cancel; xfs_trans_ijoin(args.trans, dp, 0); - error = xfs_attr_set_args(&args, &leaf_bp); + error = xfs_attr_set_args(&args); if (error) - goto out_release_leaf; + goto out_trans_cancel; if (!args.trans) { /* shortform attribute has already been committed */ goto out_unlock; @@ -408,9 +400,6 @@ xfs_attr_set( xfs_iunlock(dp, XFS_ILOCK_EXCL); return error; -out_release_leaf: - if (leaf_bp) - xfs_trans_brelse(args.trans, leaf_bp); out_trans_cancel: if (args.trans) xfs_trans_cancel(args.trans); diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h index bdf52a333f3f..cc04ee0aacfb 100644 --- a/fs/xfs/libxfs/xfs_attr.h +++ b/fs/xfs/libxfs/xfs_attr.h @@ -140,7 +140,7 @@ int xfs_attr_get(struct xfs_inode *ip, const unsigned char *name, unsigned char *value, int *valuelenp, int flags); int xfs_attr_set(struct xfs_inode *dp, const unsigned char *name, unsigned char *value, int valuelen, int flags); -int xfs_attr_set_args(struct xfs_da_args *args, struct xfs_buf **leaf_bp); +int xfs_attr_set_args(struct xfs_da_args *args); int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name, int flags); int xfs_attr_remove_args(struct xfs_da_args *args); int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize, diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c index e792b167150a..c52beee31836 100644 --- a/fs/xfs/libxfs/xfs_defer.c +++ b/fs/xfs/libxfs/xfs_defer.c @@ -266,13 +266,15 @@ xfs_defer_trans_roll( trace_xfs_defer_trans_roll(tp, _RET_IP_); - /* Roll the transaction. */ + /* + * Roll the transaction. Rolling always given a new transaction (even + * if committing the old one fails!) to hand back to the caller, so we + * join the held resources to the new transaction so that we always + * return with the held resources joined to @tpp, no matter what + * happened. + */ error = xfs_trans_roll(tpp); tp = *tpp; - if (error) { - trace_xfs_defer_trans_roll_error(tp, error); - return error; - } /* Rejoin the joined inodes. */ for (i = 0; i < ipcount; i++) @@ -284,6 +286,8 @@ xfs_defer_trans_roll( xfs_trans_bhold(tp, bplist[i]); } + if (error) + trace_xfs_defer_trans_roll_error(tp, error); return error; } diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c index 87e6dd5326d5..a1af984e4913 100644 --- a/fs/xfs/xfs_dquot.c +++ b/fs/xfs/xfs_dquot.c @@ -277,7 +277,8 @@ xfs_dquot_set_prealloc_limits(struct xfs_dquot *dqp) /* * Ensure that the given in-core dquot has a buffer on disk backing it, and - * return the buffer. This is called when the bmapi finds a hole. + * return the buffer locked and held. This is called when the bmapi finds a + * hole. */ STATIC int xfs_dquot_disk_alloc( @@ -355,13 +356,14 @@ xfs_dquot_disk_alloc( * If everything succeeds, the caller of this function is returned a * buffer that is locked and held to the transaction. The caller * is responsible for unlocking any buffer passed back, either - * manually or by committing the transaction. + * manually or by committing the transaction. On error, the buffer is + * released and not passed back. */ xfs_trans_bhold(tp, bp); error = xfs_defer_finish(tpp); - tp = *tpp; if (error) { - xfs_buf_relse(bp); + xfs_trans_bhold_release(*tpp, bp); + xfs_trans_brelse(*tpp, bp); return error; } *bpp = bp; @@ -521,7 +523,6 @@ xfs_qm_dqread_alloc( struct xfs_buf **bpp) { struct xfs_trans *tp; - struct xfs_buf *bp; int error; error = xfs_trans_alloc(mp, &M_RES(mp)->tr_qm_dqalloc, @@ -529,7 +530,7 @@ xfs_qm_dqread_alloc( if (error) goto err; - error = xfs_dquot_disk_alloc(&tp, dqp, &bp); + error = xfs_dquot_disk_alloc(&tp, dqp, bpp); if (error) goto err_cancel; @@ -539,10 +540,10 @@ xfs_qm_dqread_alloc( * Buffer was held to the transaction, so we have to unlock it * manually here because we're not passing it back. */ - xfs_buf_relse(bp); + xfs_buf_relse(*bpp); + *bpp = NULL; goto err; } - *bpp = bp; return 0; err_cancel: