Re: [PATCH v22 09/16] xfs: Implement attr logging and replay

[Allison Henderson <allison.henderson@oracle.com>]

On 7/27/21 5:39 PM, Darrick J. Wong wrote:
> On Mon, Jul 26, 2021 at 11:20:46PM -0700, Allison Henderson wrote:
>> This patch adds the needed routines to create, log and recover logged
>> extended attribute intents.
>>
>> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
>> ---
>>   fs/xfs/libxfs/xfs_defer.c  |   1 +
>>   fs/xfs/libxfs/xfs_defer.h  |   1 +
>>   fs/xfs/libxfs/xfs_format.h |  10 +-
>>   fs/xfs/xfs_attr_item.c     | 377 +++++++++++++++++++++++++++++++++++++++++++++
>>   4 files changed, 388 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
>> index eff4a12..e9caff7 100644
>> --- a/fs/xfs/libxfs/xfs_defer.c
>> +++ b/fs/xfs/libxfs/xfs_defer.c
>> @@ -178,6 +178,7 @@ static const struct xfs_defer_op_type *defer_op_types[] = {
>>   	[XFS_DEFER_OPS_TYPE_RMAP]	= &xfs_rmap_update_defer_type,
>>   	[XFS_DEFER_OPS_TYPE_FREE]	= &xfs_extent_free_defer_type,
>>   	[XFS_DEFER_OPS_TYPE_AGFL_FREE]	= &xfs_agfl_free_defer_type,
>> +	[XFS_DEFER_OPS_TYPE_ATTR]	= &xfs_attr_defer_type,
>>   };
>>   
>>   static void
>> diff --git a/fs/xfs/libxfs/xfs_defer.h b/fs/xfs/libxfs/xfs_defer.h
>> index 0ed9dfa..72a5789 100644
>> --- a/fs/xfs/libxfs/xfs_defer.h
>> +++ b/fs/xfs/libxfs/xfs_defer.h
>> @@ -19,6 +19,7 @@ enum xfs_defer_ops_type {
>>   	XFS_DEFER_OPS_TYPE_RMAP,
>>   	XFS_DEFER_OPS_TYPE_FREE,
>>   	XFS_DEFER_OPS_TYPE_AGFL_FREE,
>> +	XFS_DEFER_OPS_TYPE_ATTR,
>>   	XFS_DEFER_OPS_TYPE_MAX,
>>   };
>>   
>> diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
>> index 3a4da111..93c1263 100644
>> --- a/fs/xfs/libxfs/xfs_format.h
>> +++ b/fs/xfs/libxfs/xfs_format.h
>> @@ -485,7 +485,9 @@ xfs_sb_has_incompat_feature(
>>   	return (sbp->sb_features_incompat & feature) != 0;
>>   }
>>   
>> -#define XFS_SB_FEAT_INCOMPAT_LOG_ALL 0
>> +#define XFS_SB_FEAT_INCOMPAT_LOG_DELATTR   (1 << 0)	/* Delayed Attributes */
> 
> Echoing the conversation going on in IRC, can we change the name of this
> feature bit/flag/function?  What we're really describing here is using
> log-intent-based extended attribute updates.
> 
> IOWS, how about XFS_SB_FEAT_INCOMPAT_LOG_XATTRS?
Sure, that's fine.

> 
>> +#define XFS_SB_FEAT_INCOMPAT_LOG_ALL \
>> +	(XFS_SB_FEAT_INCOMPAT_LOG_DELATTR)
>>   #define XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN	~XFS_SB_FEAT_INCOMPAT_LOG_ALL
>>   static inline bool
>>   xfs_sb_has_incompat_log_feature(
>> @@ -590,6 +592,12 @@ static inline bool xfs_sb_version_hasbigtime(struct xfs_sb *sbp)
>>   		(sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_BIGTIME);
>>   }
>>   
>> +static inline bool xfs_sb_version_hasdelattr(struct xfs_sb *sbp)
> 
> sb_version_haslogxattrs?
Ok, will update

> 
>> +{
>> +	return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
>> +		(sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_LOG_DELATTR);
> 
> sb_features_log_incompat, as Chandan pointed out.
Yep, will fix

> 
>> +}
>> +
>>   /*
>>    * Inode btree block counter.  We record the number of inobt and finobt blocks
>>    * in the AGI header so that we can skip the finobt walk at mount time when
>> diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
>> index a810c2a..44c44d9 100644
>> --- a/fs/xfs/xfs_attr_item.c
>> +++ b/fs/xfs/xfs_attr_item.c
>> @@ -275,6 +275,182 @@ xfs_attrd_item_release(
>>   	xfs_attrd_item_free(attrdp);
>>   }
>>   
>> +/*
>> + * Performs one step of an attribute update intent and marks the attrd item
>> + * dirty..  An attr operation may be a set or a remove.  Note that the
>> + * transaction is marked dirty regardless of whether the operation succeeds or
>> + * fails to support the ATTRI/ATTRD lifecycle rules.
>> + */
>> +STATIC int
>> +xfs_trans_attr_finish_update(
>> +	struct xfs_delattr_context	*dac,
>> +	struct xfs_attrd_log_item	*attrdp,
>> +	struct xfs_buf			**leaf_bp,
>> +	uint32_t			op_flags)
>> +{
>> +	struct xfs_da_args		*args = dac->da_args;
>> +	unsigned int			op = op_flags &
>> +					     XFS_ATTR_OP_FLAGS_TYPE_MASK;
>> +	int				error;
>> +
>> +	error = xfs_qm_dqattach_locked(args->dp, 0);
>> +	if (error)
>> +		return error;
> 
> We already attached dquots in xlog_recover_iget, so you can remove this
> entirely.
I see, ok then, will clean out

> 
>> +
>> +	switch (op) {
>> +	case XFS_ATTR_OP_FLAGS_SET:
>> +		args->op_flags |= XFS_DA_OP_ADDNAME;
>> +		error = xfs_attr_set_iter(dac, leaf_bp);
>> +		break;
>> +	case XFS_ATTR_OP_FLAGS_REMOVE:
>> +		ASSERT(XFS_IFORK_Q(args->dp));
>> +		error = xfs_attr_remove_iter(dac);
>> +		break;
>> +	default:
>> +		error = -EFSCORRUPTED;
>> +		break;
>> +	}
>> +
>> +	/*
>> +	 * Mark the transaction dirty, even on error. This ensures the
>> +	 * transaction is aborted, which:
>> +	 *
>> +	 * 1.) releases the ATTRI and frees the ATTRD
>> +	 * 2.) shuts down the filesystem
>> +	 */
>> +	args->trans->t_flags |= XFS_TRANS_DIRTY;
>> +
>> +	/*
>> +	 * attr intent/done items are null when delayed attributes are disabled
>> +	 */
>> +	if (attrdp)
>> +		set_bit(XFS_LI_DIRTY, &attrdp->attrd_item.li_flags);
>> +
>> +	return error;
>> +}
>> +
>> +/* Log an attr to the intent item. */
>> +STATIC void
>> +xfs_attr_log_item(
>> +	struct xfs_trans		*tp,
>> +	struct xfs_attri_log_item	*attrip,
>> +	struct xfs_attr_item		*attr)
>> +{
>> +	struct xfs_attri_log_format	*attrp;
>> +
>> +	tp->t_flags |= XFS_TRANS_DIRTY;
>> +	set_bit(XFS_LI_DIRTY, &attrip->attri_item.li_flags);
>> +
>> +	/*
>> +	 * At this point the xfs_attr_item has been constructed, and we've
>> +	 * created the log intent. Fill in the attri log item and log format
>> +	 * structure with fields from this xfs_attr_item
>> +	 */
>> +	attrp = &attrip->attri_format;
>> +	attrp->alfi_ino = attr->xattri_dac.da_args->dp->i_ino;
>> +	attrp->alfi_op_flags = attr->xattri_op_flags;
>> +	attrp->alfi_value_len = attr->xattri_dac.da_args->valuelen;
>> +	attrp->alfi_name_len = attr->xattri_dac.da_args->namelen;
>> +	attrp->alfi_attr_flags = attr->xattri_dac.da_args->attr_filter;
>> +
>> +	attrip->attri_name = (void *)attr->xattri_dac.da_args->name;
>> +	attrip->attri_value = attr->xattri_dac.da_args->value;
>> +	attrip->attri_name_len = attr->xattri_dac.da_args->namelen;
>> +	attrip->attri_value_len = attr->xattri_dac.da_args->valuelen;
>> +}
>> +
>> +/* Get an ATTRI. */
>> +static struct xfs_log_item *
>> +xfs_attr_create_intent(
>> +	struct xfs_trans		*tp,
>> +	struct list_head		*items,
>> +	unsigned int			count,
>> +	bool				sort)
>> +{
>> +	struct xfs_mount		*mp = tp->t_mountp;
>> +	struct xfs_attri_log_item	*attrip;
>> +	struct xfs_attr_item		*attr;
>> +
>> +	ASSERT(count == 1);
>> +
>> +	if (!xfs_hasdelattr(mp))
> 
> At this point we should already have turned on the log incompat feature
> bit if the sysadmin used the secret mount option, correct?  In that
> case, I think this check should be
> 
> 	if (!xfs_sb_version_haslogxattrs(&mp->m_sb))
> 		return NULL;
Sure, that should be fine

> 
>> +		return NULL;
>> +
>> +	attrip = xfs_attri_init(mp, 0);
>> +	if (attrip == NULL)
>> +		return NULL;
>> +
>> +	xfs_trans_add_item(tp, &attrip->attri_item);
>> +	list_for_each_entry(attr, items, xattri_list)
>> +		xfs_attr_log_item(tp, attrip, attr);
>> +	return &attrip->attri_item;
>> +}
>> +
>> +/* Process an attr. */
>> +STATIC int
>> +xfs_attr_finish_item(
>> +	struct xfs_trans		*tp,
>> +	struct xfs_log_item		*done,
>> +	struct list_head		*item,
>> +	struct xfs_btree_cur		**state)
>> +{
>> +	struct xfs_attr_item		*attr;
>> +	struct xfs_attrd_log_item	*done_item = NULL;
>> +	int				error;
>> +	struct xfs_delattr_context	*dac;
>> +
>> +	attr = container_of(item, struct xfs_attr_item, xattri_list);
>> +	dac = &attr->xattri_dac;
>> +	if (done)
>> +		done_item = ATTRD_ITEM(done);
>> +
>> +	/*
>> +	 * Corner case that can happen during a recovery.  Because the first
>> +	 * iteration of a multi part delay op happens in xfs_attri_item_recover
>> +	 * to maintain the order of the log replay items.  But the new
>> +	 * transactions do not automatically rejoin during a recovery as they do
>> +	 * in a standard delay op, so we need to catch this here and rejoin the
>> +	 * leaf to the new transaction
>> +	 */
>> +	if (attr->xattri_dac.leaf_bp &&
>> +	    attr->xattri_dac.leaf_bp->b_transp != tp) {
>> +		xfs_trans_bjoin(tp, attr->xattri_dac.leaf_bp);
>> +		xfs_trans_bhold(tp, attr->xattri_dac.leaf_bp);
>> +	}
> 
> This is subtle.  The attri recovery function makes a direct call to
> xfs_trans_attr_finish_update before doing the capture-and-commit dance.
> When the captured items get replayed (separately) the defer ops
> mechanism calls this function, and that's the point at which we end up
> here needing to join and hold the leaf_bp to the transaction.
> 
> Do we have a reference to leaf_bp at this point?  When we return from
> xfs_trans_attr_finish_update in xfs_attri_item_recover, the leaf_bp (if
> any) is joined and held to the transaction that is committed in the
> "commit and capture".  Following the transaction commit I /think/ it's
> the case that we still have a reference to the leaf_bp?
> 
> So we have a reference to the leaf_bp and eventually we need to join it
> to the transaction that's used to continue the recovery.  What if the
> capture and commit function detected buffers that are bheld to the
> transaction and recorded them in the capture structure so that
> xlog_finish_defer_ops could do this part for you?
I see, I think what you are describeing should work, I will poke around 
in the capture commit routines and see if I can get that to work.

> 
>> +
>> +	/*
>> +	 * Always reset trans after EAGAIN cycle
>> +	 * since the transaction is new
>> +	 */
>> +	dac->da_args->trans = tp;
>> +
>> +	error = xfs_trans_attr_finish_update(dac, done_item, &dac->leaf_bp,
>> +					     attr->xattri_op_flags);
>> +	if (error != -EAGAIN)
>> +		kmem_free(attr);
>> +
>> +	return error;
>> +}
>> +
>> +/* Abort all pending ATTRs. */
>> +STATIC void
>> +xfs_attr_abort_intent(
>> +	struct xfs_log_item		*intent)
>> +{
>> +	xfs_attri_release(ATTRI_ITEM(intent));
>> +}
>> +
>> +/* Cancel an attr */
>> +STATIC void
>> +xfs_attr_cancel_item(
>> +	struct list_head		*item)
>> +{
>> +	struct xfs_attr_item		*attr;
>> +
>> +	attr = container_of(item, struct xfs_attr_item, xattri_list);
>> +	kmem_free(attr);
>> +}
>> +
>>   STATIC xfs_lsn_t
>>   xfs_attri_item_committed(
>>   	struct xfs_log_item		*lip,
>> @@ -306,6 +482,30 @@ xfs_attri_item_match(
>>   	return ATTRI_ITEM(lip)->attri_format.alfi_id == intent_id;
>>   }
>>   
>> +/*
>> + * This routine is called to allocate an "attr free done" log item.
>> + */
>> +static struct xfs_attrd_log_item *
>> +xfs_trans_get_attrd(struct xfs_trans		*tp,
>> +		  struct xfs_attri_log_item	*attrip)
>> +{
>> +	struct xfs_attrd_log_item		*attrdp;
>> +	uint					size;
>> +
>> +	ASSERT(tp != NULL);
>> +
>> +	size = sizeof(struct xfs_attrd_log_item);
>> +	attrdp = kmem_zalloc(size, 0);
>> +
>> +	xfs_log_item_init(tp->t_mountp, &attrdp->attrd_item, XFS_LI_ATTRD,
>> +			  &xfs_attrd_item_ops);
>> +	attrdp->attrd_attrip = attrip;
>> +	attrdp->attrd_format.alfd_alf_id = attrip->attri_format.alfi_id;
>> +
>> +	xfs_trans_add_item(tp, &attrdp->attrd_item);
>> +	return attrdp;
>> +}
>> +
>>   static const struct xfs_item_ops xfs_attrd_item_ops = {
>>   	.flags		= XFS_ITEM_RELEASE_WHEN_COMMITTED,
>>   	.iop_size	= xfs_attrd_item_size,
>> @@ -313,6 +513,29 @@ static const struct xfs_item_ops xfs_attrd_item_ops = {
>>   	.iop_release    = xfs_attrd_item_release,
>>   };
>>   
>> +
>> +/* Get an ATTRD so we can process all the attrs. */
>> +static struct xfs_log_item *
>> +xfs_attr_create_done(
>> +	struct xfs_trans		*tp,
>> +	struct xfs_log_item		*intent,
>> +	unsigned int			count)
>> +{
>> +	if (!intent)
>> +		return NULL;
>> +
>> +	return &xfs_trans_get_attrd(tp, ATTRI_ITEM(intent))->attrd_item;
>> +}
>> +
>> +const struct xfs_defer_op_type xfs_attr_defer_type = {
>> +	.max_items	= 1,
>> +	.create_intent	= xfs_attr_create_intent,
>> +	.abort_intent	= xfs_attr_abort_intent,
>> +	.create_done	= xfs_attr_create_done,
>> +	.finish_item	= xfs_attr_finish_item,
>> +	.cancel_item	= xfs_attr_cancel_item,
>> +};
>> +
>>   /* Is this recovered ATTRI ok? */
>>   static inline bool
>>   xfs_attri_validate(
>> @@ -340,13 +563,167 @@ xfs_attri_validate(
>>   	return xfs_hasdelattr(mp);
>>   }
>>   
>> +/*
>> + * Process an attr intent item that was recovered from the log.  We need to
>> + * delete the attr that it describes.
>> + */
>> +STATIC int
>> +xfs_attri_item_recover(
>> +	struct xfs_log_item		*lip,
>> +	struct list_head		*capture_list)
>> +{
>> +	struct xfs_attri_log_item	*attrip = ATTRI_ITEM(lip);
>> +	struct xfs_attr_item		*attr;
>> +	struct xfs_mount		*mp = lip->li_mountp;
>> +	struct xfs_inode		*ip;
>> +	struct xfs_da_args		*args;
>> +	struct xfs_trans		*tp;
>> +	struct xfs_trans_res		tres;
>> +	struct xfs_attri_log_format	*attrp;
>> +	int				error, ret = 0;
>> +	int				total;
>> +	int				local;
>> +	struct xfs_attrd_log_item	*done_item = NULL;
>> +
>> +	/*
>> +	 * First check the validity of the attr described by the ATTRI.  If any
>> +	 * are bad, then assume that all are bad and just toss the ATTRI.
>> +	 */
>> +	attrp = &attrip->attri_format;
>> +	if (!xfs_attri_validate(mp, attrip))
>> +		return -EFSCORRUPTED;
>> +
>> +	error = xlog_recover_iget(mp,  attrp->alfi_ino, &ip);
>> +	if (error)
>> +		return error;
>> +
>> +	attr = kmem_zalloc(sizeof(struct xfs_attr_item) +
>> +			   sizeof(struct xfs_da_args), KM_NOFS);
>> +	args = (struct xfs_da_args *)((char *)attr +
>> +		   sizeof(struct xfs_attr_item));
> 
> 	args = (struct xfs_da_args *)(attr + 1); ?
Sure, should be fine.  Thanks for the reviews!
Allison

> 
> --D
> 
>> +
>> +	attr->xattri_dac.da_args = args;
>> +	attr->xattri_op_flags = attrp->alfi_op_flags;
>> +
>> +	args->dp = ip;
>> +	args->geo = mp->m_attr_geo;
>> +	args->op_flags = attrp->alfi_op_flags;
>> +	args->whichfork = XFS_ATTR_FORK;
>> +	args->name = attrip->attri_name;
>> +	args->namelen = attrp->alfi_name_len;
>> +	args->hashval = xfs_da_hashname(args->name, args->namelen);
>> +	args->attr_filter = attrp->alfi_attr_flags;
>> +
>> +	if (attrp->alfi_op_flags == XFS_ATTR_OP_FLAGS_SET) {
>> +		args->value = attrip->attri_value;
>> +		args->valuelen = attrp->alfi_value_len;
>> +		args->total = xfs_attr_calc_size(args, &local);
>> +
>> +		tres.tr_logres = M_RES(mp)->tr_attrsetm.tr_logres +
>> +				 M_RES(mp)->tr_attrsetrt.tr_logres *
>> +					args->total;
>> +		tres.tr_logcount = XFS_ATTRSET_LOG_COUNT;
>> +		tres.tr_logflags = XFS_TRANS_PERM_LOG_RES;
>> +		total = args->total;
>> +	} else {
>> +		tres = M_RES(mp)->tr_attrrm;
>> +		total = XFS_ATTRRM_SPACE_RES(mp);
>> +	}
>> +	error = xfs_trans_alloc(mp, &tres, total, 0, XFS_TRANS_RESERVE, &tp);
>> +	if (error)
>> +		goto out;
>> +
>> +	args->trans = tp;
>> +	done_item = xfs_trans_get_attrd(tp, attrip);
>> +
>> +	xfs_ilock(ip, XFS_ILOCK_EXCL);
>> +	xfs_trans_ijoin(tp, ip, 0);
>> +
>> +	ret = xfs_trans_attr_finish_update(&attr->xattri_dac, done_item,
>> +					   &attr->xattri_dac.leaf_bp,
>> +					   attrp->alfi_op_flags);
>> +	if (ret == -EAGAIN) {
>> +		/* There's more work to do, so add it to this transaction */
>> +		xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_ATTR, &attr->xattri_list);
>> +	} else
>> +		error = ret;
>> +
>> +	if (error) {
>> +		xfs_trans_cancel(tp);
>> +		goto out_unlock;
>> +	}
>> +
>> +	error = xfs_defer_ops_capture_and_commit(tp, ip, capture_list);
>> +
>> +out_unlock:
>> +	xfs_iunlock(ip, XFS_ILOCK_EXCL);
>> +	xfs_irele(ip);
>> +out:
>> +	if (ret != -EAGAIN)
>> +		kmem_free(attr);
>> +	return error;
>> +}
>> +
>> +/* Re-log an intent item to push the log tail forward. */
>> +static struct xfs_log_item *
>> +xfs_attri_item_relog(
>> +	struct xfs_log_item		*intent,
>> +	struct xfs_trans		*tp)
>> +{
>> +	struct xfs_attrd_log_item	*attrdp;
>> +	struct xfs_attri_log_item	*old_attrip;
>> +	struct xfs_attri_log_item	*new_attrip;
>> +	struct xfs_attri_log_format	*new_attrp;
>> +	struct xfs_attri_log_format	*old_attrp;
>> +	int				buffer_size;
>> +
>> +	old_attrip = ATTRI_ITEM(intent);
>> +	old_attrp = &old_attrip->attri_format;
>> +	buffer_size = old_attrp->alfi_value_len + old_attrp->alfi_name_len;
>> +
>> +	tp->t_flags |= XFS_TRANS_DIRTY;
>> +	attrdp = xfs_trans_get_attrd(tp, old_attrip);
>> +	set_bit(XFS_LI_DIRTY, &attrdp->attrd_item.li_flags);
>> +
>> +	new_attrip = xfs_attri_init(tp->t_mountp, buffer_size);
>> +	new_attrp = &new_attrip->attri_format;
>> +
>> +	new_attrp->alfi_ino = old_attrp->alfi_ino;
>> +	new_attrp->alfi_op_flags = old_attrp->alfi_op_flags;
>> +	new_attrp->alfi_value_len = old_attrp->alfi_value_len;
>> +	new_attrp->alfi_name_len = old_attrp->alfi_name_len;
>> +	new_attrp->alfi_attr_flags = old_attrp->alfi_attr_flags;
>> +
>> +	new_attrip->attri_name_len = old_attrip->attri_name_len;
>> +	new_attrip->attri_name = ((char *)new_attrip) +
>> +				 sizeof(struct xfs_attri_log_item);
>> +	memcpy(new_attrip->attri_name, old_attrip->attri_name,
>> +		new_attrip->attri_name_len);
>> +
>> +	new_attrip->attri_value_len = old_attrip->attri_value_len;
>> +	if (new_attrip->attri_value_len > 0) {
>> +		new_attrip->attri_value = new_attrip->attri_name +
>> +					  new_attrip->attri_name_len;
>> +
>> +		memcpy(new_attrip->attri_value, old_attrip->attri_value,
>> +		       new_attrip->attri_value_len);
>> +	}
>> +
>> +	xfs_trans_add_item(tp, &new_attrip->attri_item);
>> +	set_bit(XFS_LI_DIRTY, &new_attrip->attri_item.li_flags);
>> +
>> +	return &new_attrip->attri_item;
>> +}
>> +
>>   static const struct xfs_item_ops xfs_attri_item_ops = {
>>   	.iop_size	= xfs_attri_item_size,
>>   	.iop_format	= xfs_attri_item_format,
>>   	.iop_unpin	= xfs_attri_item_unpin,
>>   	.iop_committed	= xfs_attri_item_committed,
>>   	.iop_release    = xfs_attri_item_release,
>> +	.iop_recover	= xfs_attri_item_recover,
>>   	.iop_match	= xfs_attri_item_match,
>> +	.iop_relog	= xfs_attri_item_relog,
>>   };
>>   
>>   
>> -- 
>> 2.7.4
>>