From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EECFBC433EF for ; Fri, 20 May 2022 14:21:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350217AbiETOVs (ORCPT ); Fri, 20 May 2022 10:21:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233881AbiETOVp (ORCPT ); Fri, 20 May 2022 10:21:45 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3BD160045; Fri, 20 May 2022 07:21:44 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 61B9C21A89; Fri, 20 May 2022 14:21:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1653056503; h=from:from:reply-to: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=Z3HjEeZ6v9eJRGMzuAUOJEIH0zziIHl1MeGRpDqDTDo=; b=gkkCIYhiHP+lvVa27jTaz4AaoSo3uu8QJdQMxnGo5oEC44Svb1DyQQFBfSC0+R707pzNVt W9EDJSV4fVdRnoO/6LC4oh6HcXCw1UvL96K/SS5VHs4EoB3aEg3cVy2tw6G3YRLkzOk35c R+PGdVeQJg5EOHOKYwoNL7w844KNGxo= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1653056503; h=from:from:reply-to: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=Z3HjEeZ6v9eJRGMzuAUOJEIH0zziIHl1MeGRpDqDTDo=; b=+tLacv2PSOdpysuaM1/Fs4vqo/rnwr04rkPcSzSPmPeTesiLR5263MBBltToAinx9ngC7F 5GkMGLOF2yhO0GCA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id EEC1213AF4; Fri, 20 May 2022 14:21:42 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id KOJXN/ajh2J5ewAAMHmgww (envelope-from ); Fri, 20 May 2022 14:21:42 +0000 Received: from localhost (brahms.olymp [local]) by brahms.olymp (OpenSMTPD) with ESMTPA id 9575b903; Fri, 20 May 2022 14:22:20 +0000 (UTC) From: =?utf-8?Q?Lu=C3=ADs_Henriques?= To: Jeff Layton Cc: Xiubo Li , Ilya Dryomov , ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] ceph: try to prevent exceeding the MDS maximum xattr size References: <20220520115426.438-1-lhenriques@suse.de> Date: Fri, 20 May 2022 15:22:20 +0100 In-Reply-To: <20220520115426.438-1-lhenriques@suse.de> (=?utf-8?Q?=22Lu?= =?utf-8?Q?=C3=ADs?= Henriques"'s message of "Fri, 20 May 2022 12:54:26 +0100") Message-ID: <87ee0o2sir.fsf@brahms.olymp> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Lu=C3=ADs Henriques writes: > The MDS tries to enforce a limit on the total key/values in extended > attributes. However, this limit is enforced only if doing a synchronous > operation (MDS_OP_SETXATTR) -- if we're buffering the xattrs, the MDS > doesn't have a chance to enforce these limits. > > This patch forces the usage of the synchronous operation if xattrs size h= its > the maximum size that is set on the MDS by default (64k). > > While there, fix a dout() that would trigger a printk warning: > > [ 98.718078] ------------[ cut here ]------------ > [ 98.719012] precision 65536 too large > [ 98.719039] WARNING: CPU: 1 PID: 3755 at lib/vsprintf.c:2703 vsnprintf= +0x5e3/0x600 > ... > > URL: https://tracker.ceph.com/issues/55725 > Signed-off-by: Lu=C3=ADs Henriques > --- > fs/ceph/xattr.c | 17 +++++++++++++---- > 1 file changed, 13 insertions(+), 4 deletions(-) > > diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c > index afec84088471..09751a5f028c 100644 > --- a/fs/ceph/xattr.c > +++ b/fs/ceph/xattr.c > @@ -15,6 +15,12 @@ > #define XATTR_CEPH_PREFIX "ceph." > #define XATTR_CEPH_PREFIX_LEN (sizeof (XATTR_CEPH_PREFIX) - 1) >=20=20 > +/* > + * Maximum size of xattrs the MDS can handle per inode by default. This > + * includes the attribute name and 4+4 bytes for the key/value sizes. > + */ > +#define MDS_MAX_XATTR_PAIRS_SIZE (1<<16) /* 64K */ > + > static int __remove_xattr(struct ceph_inode_info *ci, > struct ceph_inode_xattr *xattr); >=20=20 > @@ -1078,7 +1084,7 @@ static int ceph_sync_setxattr(struct inode *inode, = const char *name, > flags |=3D CEPH_XATTR_REMOVE; > } >=20=20 > - dout("setxattr value=3D%.*s\n", (int)size, value); > + dout("setxattr value size: ld\n", size); Oops! Looks like someone ate a '%' char. Oh well, I won't bother sending out a new version for now as this is an RFC and the MDS side is what really needs fixing. In fact, the client-side may be something very different from this RFC. Cheers, --=20 Lu=C3=ADs >=20=20 > /* do request */ > req =3D ceph_mdsc_create_request(mdsc, op, USE_AUTH_MDS); > @@ -1176,8 +1182,13 @@ int __ceph_setxattr(struct inode *inode, const cha= r *name, > spin_lock(&ci->i_ceph_lock); > retry: > issued =3D __ceph_caps_issued(ci, NULL); > - if (ci->i_xattrs.version =3D=3D 0 || !(issued & CEPH_CAP_XATTR_EXCL)) > + required_blob_size =3D __get_required_blob_size(ci, name_len, val_len); > + if ((ci->i_xattrs.version =3D=3D 0) || !(issued & CEPH_CAP_XATTR_EXCL) = || > + (required_blob_size >=3D MDS_MAX_XATTR_PAIRS_SIZE)) { > + dout("%s do sync setxattr: version: %llu blob size: %d\n", > + __func__, ci->i_xattrs.version, required_blob_size); > goto do_sync; > + } >=20=20 > if (!lock_snap_rwsem && !ci->i_head_snapc) { > lock_snap_rwsem =3D true; > @@ -1193,8 +1204,6 @@ int __ceph_setxattr(struct inode *inode, const char= *name, > ceph_cap_string(issued)); > __build_xattrs(inode); >=20=20 > - required_blob_size =3D __get_required_blob_size(ci, name_len, val_len); > - > if (!ci->i_xattrs.prealloc_blob || > required_blob_size > ci->i_xattrs.prealloc_blob->alloc_len) { > struct ceph_buffer *blob;