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 X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 97B44C4338F for ; Wed, 28 Jul 2021 19:24:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 72D376103A for ; Wed, 28 Jul 2021 19:24:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229542AbhG1TYV (ORCPT ); Wed, 28 Jul 2021 15:24:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:46692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230444AbhG1TYV (ORCPT ); Wed, 28 Jul 2021 15:24:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 47D496101E; Wed, 28 Jul 2021 19:24:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627500259; bh=IAQs1uGu5PADLRfG/89bw9Mkbb1/QwRdgz00jWMBs5k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ilzbN5vRrbkKGZQVDLl4LSTpr+eGOu7nMZIa9+xrD4Sb5UWnGwFqYZDSQnfQTn7pu 0aHMlC09xX3Ep+rCmDIUfiDRKk2C2yZob7d9zUcTsBdX9ftOrWvZhAFN6uVLJJnajS q8bsREXhpsGiUV2MP5nDqSN5ZGudlPT3bvNAaF5BtzHSixJfKkg0zlq3a+/MK/Cwqd f4f8G3D0ouYqrCJAuJ2/i3RU4eP3VymDyA/7SR/yZRO8DwZdMGeBSK1IkA74DFt80L 67TfRL3rKBQpGPHo5Z9vlvswObpdQqsXeOLbI4hn94hP7nlfdqryywHv8/IgsNvE4q Vysx01PfyW62w== Date: Wed, 28 Jul 2021 12:24:18 -0700 From: "Darrick J. Wong" To: Allison Henderson Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH v22 11/16] xfs: Add xfs_attr_set_deferred and xfs_attr_remove_deferred Message-ID: <20210728192418.GE3601443@magnolia> References: <20210727062053.11129-1-allison.henderson@oracle.com> <20210727062053.11129-12-allison.henderson@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210727062053.11129-12-allison.henderson@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Jul 26, 2021 at 11:20:48PM -0700, Allison Henderson wrote: > From: Allison Collins > > These routines set up and queue a new deferred attribute operations. > These functions are meant to be called by any routine needing to > initiate a deferred attribute operation as opposed to the existing > inline operations. New helper function xfs_attr_item_init also added. > > Finally enable delayed attributes in xfs_attr_set and xfs_attr_remove. > > Signed-off-by: Allison Henderson > Reviewed-by: Darrick J. Wong > --- > fs/xfs/libxfs/xfs_attr.c | 70 +++++++++++++++++++++++++++++++++++++++++++++--- > fs/xfs/libxfs/xfs_attr.h | 2 ++ > fs/xfs/xfs_log.c | 41 ++++++++++++++++++++++++++++ > fs/xfs/xfs_log.h | 1 + > 4 files changed, 111 insertions(+), 3 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c > index eee219c6..c447c21 100644 > --- a/fs/xfs/libxfs/xfs_attr.c > +++ b/fs/xfs/libxfs/xfs_attr.c > @@ -25,6 +25,8 @@ > #include "xfs_trans_space.h" > #include "xfs_trace.h" > #include "xfs_attr_item.h" > +#include "xfs_attr.h" > +#include "xfs_log.h" > > /* > * xfs_attr.c > @@ -779,13 +781,19 @@ xfs_attr_set( > rmt_blks = xfs_attr3_rmt_blocks(mp, XFS_XATTR_SIZE_MAX); > } > > + if (xfs_hasdelattr(mp)) { > + error = xfs_attr_use_log_assist(mp); > + if (error) > + return error; > + } > + > /* > * Root fork attributes can use reserved data blocks for this > * operation if necessary > */ > error = xfs_trans_alloc_inode(dp, &tres, total, 0, rsvd, &args->trans); > if (error) > - return error; > + goto drop_incompat; > > if (args->value || xfs_inode_hasattr(dp)) { > error = xfs_iext_count_may_overflow(dp, XFS_ATTR_FORK, > @@ -803,9 +811,10 @@ xfs_attr_set( > if (error != -ENOATTR && error != -EEXIST) > goto out_trans_cancel; > > - error = xfs_attr_set_args(args); > + error = xfs_attr_set_deferred(args); > if (error) > goto out_trans_cancel; > + > /* shortform attribute has already been committed */ > if (!args->trans) > goto out_unlock; > @@ -814,7 +823,7 @@ xfs_attr_set( > if (error != -EEXIST) > goto out_trans_cancel; > > - error = xfs_attr_remove_args(args); > + error = xfs_attr_remove_deferred(args); > if (error) > goto out_trans_cancel; > } > @@ -836,6 +845,9 @@ xfs_attr_set( > error = xfs_trans_commit(args->trans); > out_unlock: > xfs_iunlock(dp, XFS_ILOCK_EXCL); > +drop_incompat: > + if (xfs_hasdelattr(mp)) Subtle race here: if you turn this into a debug option and someone changes the value from 1 to 0 while this function is running, we'll fail to call _drop_incompat here. You should sample the value at the start of the function into a local variable and use that throughout. > + xlog_drop_incompat_feat(mp->m_log); > return error; > > out_trans_cancel: > @@ -844,6 +856,58 @@ xfs_attr_set( > goto out_unlock; > } > > +STATIC int > +xfs_attr_item_init( > + struct xfs_da_args *args, > + unsigned int op_flags, /* op flag (set or remove) */ > + struct xfs_attr_item **attr) /* new xfs_attr_item */ > +{ > + > + struct xfs_attr_item *new; > + > + new = kmem_zalloc(sizeof(struct xfs_attr_item), KM_NOFS); > + new->xattri_op_flags = op_flags; > + new->xattri_dac.da_args = args; > + > + *attr = new; > + return 0; > +} > + > +/* Sets an attribute for an inode as a deferred operation */ > +int > +xfs_attr_set_deferred( > + struct xfs_da_args *args) > +{ > + struct xfs_attr_item *new; > + int error = 0; > + > + error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_SET, &new); > + if (error) > + return error; > + > + xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list); > + > + return 0; > +} > + > +/* Removes an attribute for an inode as a deferred operation */ > +int > +xfs_attr_remove_deferred( > + struct xfs_da_args *args) > +{ > + > + struct xfs_attr_item *new; > + int error; > + > + error = xfs_attr_item_init(args, XFS_ATTR_OP_FLAGS_REMOVE, &new); > + if (error) > + return error; > + > + xfs_defer_add(args->trans, XFS_DEFER_OPS_TYPE_ATTR, &new->xattri_list); > + > + return 0; > +} > + > /*======================================================================== > * External routines when attribute list is inside the inode > *========================================================================*/ > diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h > index 463b2be..72b0ea5 100644 > --- a/fs/xfs/libxfs/xfs_attr.h > +++ b/fs/xfs/libxfs/xfs_attr.h > @@ -527,5 +527,7 @@ bool xfs_attr_namecheck(const void *name, size_t length); > void xfs_delattr_context_init(struct xfs_delattr_context *dac, > struct xfs_da_args *args); > int xfs_attr_calc_size(struct xfs_da_args *args, int *local); > +int xfs_attr_set_deferred(struct xfs_da_args *args); > +int xfs_attr_remove_deferred(struct xfs_da_args *args); > > #endif /* __XFS_ATTR_H__ */ > diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c > index 7c593d9..216de6c 100644 > --- a/fs/xfs/xfs_log.c > +++ b/fs/xfs/xfs_log.c > @@ -3948,3 +3948,44 @@ xlog_drop_incompat_feat( > { > up_read(&log->l_incompat_users); > } > + > +/* > + * Get permission to use log-assisted atomic exchange of file extents. > + * > + * Callers must not be running any transactions or hold any inode locks, and > + * they must release the permission by calling xlog_drop_incompat_feat > + * when they're done. > + */ > +int > +xfs_attr_use_log_assist( > + struct xfs_mount *mp) > +{ > + int error = 0; > + > + /* > + * Protect ourselves from an idle log clearing the logged xattrs log > + * incompat feature bit. > + */ > + xlog_use_incompat_feat(mp->m_log); > + > + /* > + * If log-assisted xattrs are already enabled, the caller can use the > + * log assisted swap functions with the log-incompat reference we got. > + */ > + if (xfs_sb_version_hasdelattr(&mp->m_sb)) > + return 0; > + > + /* Enable log-assisted xattrs. */ > + xfs_warn_once(mp, > +"EXPERIMENTAL logged extended attributes feature added. Use at your own risk!"); > + > + error = xfs_add_incompat_log_feature(mp, > + XFS_SB_FEAT_INCOMPAT_LOG_DELATTR); > + if (error) > + goto drop_incompat; Minor bug here (and yes, it's also in the swapext code that I pointed you to; apologies for that): We shouldn't print the warning unless the feature addition actually succeeds. IOWs, move the xfs_warn_once() here. (That said, if the feature add fails then the fs is probably going to crash soon anyway so it probably doesn't matter...) --D > + > + return 0; > +drop_incompat: > + xlog_drop_incompat_feat(mp->m_log); > + return error; > +} > diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h > index b274fb9..1e461671 100644 > --- a/fs/xfs/xfs_log.h > +++ b/fs/xfs/xfs_log.h > @@ -144,5 +144,6 @@ xfs_lsn_t xlog_grant_push_threshold(struct xlog *log, int need_bytes); > > void xlog_use_incompat_feat(struct xlog *log); > void xlog_drop_incompat_feat(struct xlog *log); > +int xfs_attr_use_log_assist(struct xfs_mount *mp); > > #endif /* __XFS_LOG_H__ */ > -- > 2.7.4 >