Re: [PATCH v13 02/10] xfs: Add delay ready attr remove routines

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

On 10/28/20 5:04 AM, Chandan Babu R wrote:
> On Tuesday 27 October 2020 9:02:05 PM IST Allison Henderson wrote:
>>
>> On 10/27/20 2:59 AM, Chandan Babu R wrote:
>>> On Friday 23 October 2020 12:04:27 PM IST Allison Henderson wrote:
>>>> This patch modifies the attr remove routines to be delay ready. This
>>>> means they no longer roll or commit transactions, but instead return
>>>> -EAGAIN to have the calling routine roll and refresh the transaction. In
>>>> this series, xfs_attr_remove_args has become xfs_attr_remove_iter, which
>>>> uses a sort of state machine like switch to keep track of where it was
>>>> when EAGAIN was returned. xfs_attr_node_removename has also been
>>>> modified to use the switch, and a new version of xfs_attr_remove_args
>>>> consists of a simple loop to refresh the transaction until the operation
>>>> is completed.  A new XFS_DAC_DEFER_FINISH flag is used to finish the
>>>> transaction where ever the existing code used to.
>>>>
>>>> Calls to xfs_attr_rmtval_remove are replaced with the delay ready
>>>> version __xfs_attr_rmtval_remove. We will rename
>>>> __xfs_attr_rmtval_remove back to xfs_attr_rmtval_remove when we are
>>>> done.
>>>>
>>>> xfs_attr_rmtval_remove itself is still in use by the set routines (used
>>>> during a rename).  For reasons of preserving existing function, we
>>>> modify xfs_attr_rmtval_remove to call xfs_defer_finish when the flag is
>>>> set.  Similar to how xfs_attr_remove_args does here.  Once we transition
>>>> the set routines to be delay ready, xfs_attr_rmtval_remove is no longer
>>>> used and will be removed.
>>>>
>>>> This patch also adds a new struct xfs_delattr_context, which we will use
>>>> to keep track of the current state of an attribute operation. The new
>>>> xfs_delattr_state enum is used to track various operations that are in
>>>> progress so that we know not to repeat them, and resume where we left
>>>> off before EAGAIN was returned to cycle out the transaction. Other
>>>> members take the place of local variables that need to retain their
>>>> values across multiple function recalls.  See xfs_attr.h for a more
>>>> detailed diagram of the states.
>>>>
>>>> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
>>>> ---
>>>>    fs/xfs/libxfs/xfs_attr.c        | 200 +++++++++++++++++++++++++++++-----------
>>>>    fs/xfs/libxfs/xfs_attr.h        |  72 +++++++++++++++
>>>>    fs/xfs/libxfs/xfs_attr_leaf.c   |   2 +-
>>>>    fs/xfs/libxfs/xfs_attr_remote.c |  37 ++++----
>>>>    fs/xfs/libxfs/xfs_attr_remote.h |   2 +-
>>>>    fs/xfs/xfs_attr_inactive.c      |   2 +-
>>>>    6 files changed, 241 insertions(+), 74 deletions(-)
>>>>
>>>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>>>> index f4d39bf..6ca94cb 100644
>>>> --- a/fs/xfs/libxfs/xfs_attr.c
>>>> +++ b/fs/xfs/libxfs/xfs_attr.c
>>>> @@ -53,7 +53,7 @@ STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);
>>>>     */
>>>>    STATIC int xfs_attr_node_get(xfs_da_args_t *args);
>>>>    STATIC int xfs_attr_node_addname(xfs_da_args_t *args);
>>>> -STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
>>>> +STATIC int xfs_attr_node_removename_iter(struct xfs_delattr_context *dac);
>>>>    STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
>>>>    				 struct xfs_da_state **state);
>>>>    STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
>>>> @@ -264,6 +264,33 @@ xfs_attr_set_shortform(
>>>>    }
>>>>    
>>>>    /*
>>>> + * Checks to see if a delayed attribute transaction should be rolled.  If so,
>>>> + * also checks for a defer finish.  Transaction is finished and rolled as
>>>> + * needed, and returns true of false if the delayed operation should continue.
>>>> + */
>>>> +int
>>>> +xfs_attr_trans_roll(
>>>> +	struct xfs_delattr_context	*dac)
>>>> +{
>>>> +	struct xfs_da_args		*args = dac->da_args;
>>>> +	int				error = 0;
>>>> +
>>>> +	if (dac->flags & XFS_DAC_DEFER_FINISH) {
>>>> +		/*
>>>> +		 * The caller wants us to finish all the deferred ops so that we
>>>> +		 * avoid pinning the log tail with a large number of deferred
>>>> +		 * ops.
>>>> +		 */
>>>> +		dac->flags &= ~XFS_DAC_DEFER_FINISH;
>>>> +		error = xfs_defer_finish(&args->trans);
>>>> +		if (error)
>>>> +			return error;
>>>> +	}
>>>> +
>>>> +	return xfs_trans_roll_inode(&args->trans, args->dp);
>>>> +}
>>>> +
>>>> +/*
>>>>     * Set the attribute specified in @args.
>>>>     */
>>>>    int
>>>> @@ -364,23 +391,54 @@ xfs_has_attr(
>>>>     */
>>>>    int
>>>>    xfs_attr_remove_args(
>>>> -	struct xfs_da_args      *args)
>>>> +	struct xfs_da_args	*args)
>>>>    {
>>>> -	struct xfs_inode	*dp = args->dp;
>>>> -	int			error;
>>>> +	int				error = 0;
>>>
>>> I guess the explicit initialization of "error" can be removed since the
>>> value returned by the call to xfs_attr_remove_iter() will overwrite it.
>> Sure, will fix
>>>
>>>> +	struct xfs_delattr_context	dac = {
>>>> +		.da_args	= args,
>>>> +	};
>>>> +
>>>> +	do {
>>>> +		error = xfs_attr_remove_iter(&dac);
>>>> +		if (error != -EAGAIN)
>>>> +			break;
>>>> +
>>>> +		error = xfs_attr_trans_roll(&dac);
>>>> +		if (error)
>>>> +			return error;
>>>> +
>>>> +	} while (true);
>>>> +
>>>> +	return error;
>>>> +}
>>>> +
>>>> +/*
>>>> + * Remove the attribute specified in @args.
>>>> + *
>>>> + * This function may return -EAGAIN to signal that the transaction needs to be
>>>> + * rolled.  Callers should continue calling this function until they receive a
>>>> + * return value other than -EAGAIN.
>>>> + */
>>>> +int
>>>> +xfs_attr_remove_iter(
>>>> +	struct xfs_delattr_context	*dac)
>>>> +{
>>>> +	struct xfs_da_args		*args = dac->da_args;
>>>> +	struct xfs_inode		*dp = args->dp;
>>>> +
>>>> +	if (dac->dela_state == XFS_DAS_RM_SHRINK)
>>>> +		goto node;
>>>>    
>>>>    	if (!xfs_inode_hasattr(dp)) {
>>>> -		error = -ENOATTR;
>>>> +		return -ENOATTR;
>>>>    	} else if (dp->i_afp->if_format == XFS_DINODE_FMT_LOCAL) {
>>>>    		ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
>>>> -		error = xfs_attr_shortform_remove(args);
>>>> +		return xfs_attr_shortform_remove(args);
>>>>    	} else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
>>>> -		error = xfs_attr_leaf_removename(args);
>>>> -	} else {
>>>> -		error = xfs_attr_node_removename(args);
>>>> +		return xfs_attr_leaf_removename(args);
>>>>    	}
>>>> -
>>>> -	return error;
>>>> +node:
>>>> +	return  xfs_attr_node_removename_iter(dac);
>>>>    }
>>>>    
>>>>    /*
>>>> @@ -1178,10 +1236,11 @@ xfs_attr_leaf_mark_incomplete(
>>>>     */
>>>>    STATIC
>>>>    int xfs_attr_node_removename_setup(
>>>> -	struct xfs_da_args	*args,
>>>> -	struct xfs_da_state	**state)
>>>> +	struct xfs_delattr_context	*dac,
>>>> +	struct xfs_da_state		**state)
>>>>    {
>>>> -	int			error;
>>>> +	struct xfs_da_args		*args = dac->da_args;
>>>> +	int				error;
>>>>    
>>>>    	error = xfs_attr_node_hasname(args, state);
>>>>    	if (error != -EEXIST)
>>>> @@ -1191,6 +1250,12 @@ int xfs_attr_node_removename_setup(
>>>>    	ASSERT((*state)->path.blk[(*state)->path.active - 1].magic ==
>>>>    		XFS_ATTR_LEAF_MAGIC);
>>>>    
>>>> +	/*
>>>> +	 * Store state in the context incase we need to cycle out the
>>>> +	 * transaction
>>>> +	 */
>>>> +	dac->da_state = *state;
>>>> +
>>>>    	if (args->rmtblkno > 0) {
>>>>    		error = xfs_attr_leaf_mark_incomplete(args, *state);
>>>>    		if (error)
>>>> @@ -1203,13 +1268,16 @@ int xfs_attr_node_removename_setup(
>>>>    }
>>>>    
>>>>    STATIC int
>>>> -xfs_attr_node_remove_rmt(
>>>> -	struct xfs_da_args	*args,
>>>> -	struct xfs_da_state	*state)
>>>> +xfs_attr_node_remove_rmt (
>>>> +	struct xfs_delattr_context	*dac,
>>>> +	struct xfs_da_state		*state)
>>>>    {
>>>> -	int			error = 0;
>>>> +	int				error = 0;
>>>>    
>>>> -	error = xfs_attr_rmtval_remove(args);
>>>> +	/*
>>>> +	 * May return -EAGAIN to request that the caller recall this function
>>>> +	 */
>>>> +	error = __xfs_attr_rmtval_remove(dac);
>>>>    	if (error)
>>>>    		return error;
>>>>    
>>>> @@ -1221,21 +1289,27 @@ xfs_attr_node_remove_rmt(
>>>>    }
>>>>    
>>>>    /*
>>>> - * Remove a name from a B-tree attribute list.
>>>> + * Step through removeing a name from a B-tree attribute list.
>>>>     *
>>>>     * This will involve walking down the Btree, and may involve joining
>>>>     * leaf nodes and even joining intermediate nodes up to and including
>>>>     * the root node (a special case of an intermediate node).
>>>> + *
>>>> + * This routine is meant to function as either an inline or delayed operation,
>>>> + * and may return -EAGAIN when the transaction needs to be rolled.  Calling
>>>> + * functions will need to handle this, and recall the function until a
>>>> + * successful error code is returned.
>>>>     */
>>>>    STATIC int
>>>>    xfs_attr_node_remove_step(
>>>> -	struct xfs_da_args	*args,
>>>> -	struct xfs_da_state	*state)
>>>> +	struct xfs_delattr_context	*dac)
>>>>    {
>>>> -	struct xfs_da_state_blk	*blk;
>>>> -	int			retval, error;
>>>> -	struct xfs_inode	*dp = args->dp;
>>>> +	struct xfs_da_args		*args = dac->da_args;
>>>> +	struct xfs_da_state		*state;
>>>> +	struct xfs_da_state_blk		*blk;
>>>> +	int				retval, error = 0;
>>>>    
>>>> +	state = dac->da_state;
>>>>    
>>>>    	/*
>>>>    	 * If there is an out-of-line value, de-allocate the blocks.
>>>> @@ -1243,7 +1317,10 @@ xfs_attr_node_remove_step(
>>>>    	 * overflow the maximum size of a transaction and/or hit a deadlock.
>>>>    	 */
>>>>    	if (args->rmtblkno > 0) {
>>>> -		error = xfs_attr_node_remove_rmt(args, state);
>>>> +		/*
>>>> +		 * May return -EAGAIN. Remove blocks until args->rmtblkno == 0
>>>> +		 */
>>>> +		error = xfs_attr_node_remove_rmt(dac, state);
>>>>    		if (error)
>>>>    			return error;
>>>>    	}
>>>> @@ -1257,21 +1334,18 @@ xfs_attr_node_remove_step(
>>>>    	xfs_da3_fixhashpath(state, &state->path);
>>>>    
>>>>    	/*
>>>> -	 * Check to see if the tree needs to be collapsed.
>>>> +	 * Check to see if the tree needs to be collapsed.  Set the flag to
>>>> +	 * indicate that the calling function needs to move the to shrink
>>>> +	 * operation
>>>>    	 */
>>>>    	if (retval && (state->path.active > 1)) {
>>>>    		error = xfs_da3_join(state);
>>>>    		if (error)
>>>>    			return error;
>>>> -		error = xfs_defer_finish(&args->trans);
>>>> -		if (error)
>>>> -			return error;
>>>> -		/*
>>>> -		 * Commit the Btree join operation and start a new trans.
>>>> -		 */
>>>> -		error = xfs_trans_roll_inode(&args->trans, dp);
>>>> -		if (error)
>>>> -			return error;
>>>> +
>>>> +		dac->flags |= XFS_DAC_DEFER_FINISH;
>>>> +		dac->dela_state = XFS_DAS_RM_SHRINK;
>>>> +		return -EAGAIN;
>>>>    	}
>>>>    
>>>>    	return error;
>>>> @@ -1282,31 +1356,53 @@ xfs_attr_node_remove_step(
>>>>     *
>>>>     * This routine will find the blocks of the name to remove, remove them and
>>>>     * shirnk the tree if needed.
>>>> + *
>>>> + * This routine is meant to function as either an inline or delayed operation,
>>>> + * and may return -EAGAIN when the transaction needs to be rolled.  Calling
>>>> + * functions will need to handle this, and recall the function until a
>>>> + * successful error code is returned.
>>>>     */
>>>>    STATIC int
>>>> -xfs_attr_node_removename(
>>>> -	struct xfs_da_args	*args)
>>>> +xfs_attr_node_removename_iter(
>>>> +	struct xfs_delattr_context	*dac)
>>>>    {
>>>> -	struct xfs_da_state	*state;
>>>> -	int			error;
>>>> -	struct xfs_inode	*dp = args->dp;
>>>> +	struct xfs_da_args		*args = dac->da_args;
>>>> +	struct xfs_da_state		*state;
>>>> +	int				error;
>>>> +	struct xfs_inode		*dp = args->dp;
>>>>    
>>>>    	trace_xfs_attr_node_removename(args);
>>>> +	state = dac->da_state;
>>>>    
>>>> -	error = xfs_attr_node_removename_setup(args, &state);
>>>> -	if (error)
>>>> -		goto out;
>>>> +	if ((dac->flags & XFS_DAC_NODE_RMVNAME_INIT) == 0) {
>>>> +		dac->flags |= XFS_DAC_NODE_RMVNAME_INIT;
>>>> +		error = xfs_attr_node_removename_setup(dac, &state);
>>>> +		if (error)
>>>> +			goto out;
>>>> +	}
>>>>    
>>>> -	error = xfs_attr_node_remove_step(args, state);
>>>> -	if (error)
>>>> -		goto out;
>>>> +	switch (dac->dela_state) {
>>>> +	case XFS_DAS_UNINIT:
>>>> +		error = xfs_attr_node_remove_step(dac);
>>>> +		if (error)
>>>> +			break;
>>>>    
>>>> -	/*
>>>> -	 * If the result is small enough, push it all into the inode.
>>>> -	 */
>>>> -	if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
>>>> -		error = xfs_attr_node_shrink(args, state);
>>>> +		/* do not break, proceed to shrink if needed */
>>>> +	case XFS_DAS_RM_SHRINK:
>>>> +		/*
>>>> +		 * If the result is small enough, push it all into the inode.
>>>> +		 */
>>>> +		if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
>>>> +			error = xfs_attr_node_shrink(args, state);
>>>>    
>>>> +		break;
>>>> +	default:
>>>> +		ASSERT(0);
>>>> +		return -EINVAL;
>>>
>>> I don't think it is possible in a real world scenario, but if "state" were
>>> pointing to allocated memory then the above return value might leak the
>>> corresponding memory.
>> Hmm, trying to follow you here.... I'm assuming you meant dela_state
>> instead of state since that's what controls the switch.  The dac
>> structure is zeroed when allocated to avoid this.  Most of the time when
>> this switch executes, dela_state is zero.  I did have to add the
>> XFS_DAS_UNINIT from the previous suggestion in the last revision though
>> or it generates warnings.
>>>
> 
> Sorry, I should have clarified that I was referring to the allocated
> memory pointed to by dac->da_state. If dac->da_state was pointing to a valid
> memory location and dac->dela_state's value is not equal to either
> XFS_DAS_UNINIT nor XFS_DAS_RM_SHRINK then the code under the "default" clause
> will execute causing -EINVAL to be returned. This could leak the memory
> pointed to by dac->da_state.

Oooh, ok I see it.  We should set error to -EINVAL and goto out. 
Ideally it should never happen, but that should be the proper error 
handling if it did.  Thanks for the catch  :-)

Allison
> 
> 
>>> Apart from the above nit, the remaining changes look good to me.
>> Ok, thanks for the review!
>> Allison
>>
>>>
>>> Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
>>>
>>>> +	}
>>>> +
>>>> +	if (error == -EAGAIN)
>>>> +		return error;
>>>>    out:
>>>>    	if (state)
>>>>    		xfs_da_state_free(state);
>>>> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
>>>> index 3e97a93..64dcf0f 100644
>>>> --- a/fs/xfs/libxfs/xfs_attr.h
>>>> +++ b/fs/xfs/libxfs/xfs_attr.h
>>>> @@ -74,6 +74,74 @@ struct xfs_attr_list_context {
>>>>    };
>>>>    
>>>>    
>>>> +/*
>>>> + * ========================================================================
>>>> + * Structure used to pass context around among the delayed routines.
>>>> + * ========================================================================
>>>> + */
>>>> +
>>>> +/*
>>>> + * Below is a state machine diagram for attr remove operations. The  XFS_DAS_*
>>>> + * states indicate places where the function would return -EAGAIN, and then
>>>> + * immediately resume from after being recalled by the calling function. States
>>>> + * marked as a "subroutine state" indicate that they belong to a subroutine, and
>>>> + * so the calling function needs to pass them back to that subroutine to allow
>>>> + * it to finish where it left off. But they otherwise do not have a role in the
>>>> + * calling function other than just passing through.
>>>> + *
>>>> + * xfs_attr_remove_iter()
>>>> + *	  XFS_DAS_RM_SHRINK ─┐
>>>> + *	  (subroutine state) │
>>>> + *	                     └─>xfs_attr_node_removename()
>>>> + *	                                      │
>>>> + *	                                      v
>>>> + *	                                   need to
>>>> + *	                                shrink tree? ─n─┐
>>>> + *	                                      │         │
>>>> + *	                                      y         │
>>>> + *	                                      │         │
>>>> + *	                                      v         │
>>>> + *	                              XFS_DAS_RM_SHRINK │
>>>> + *	                                      │         │
>>>> + *	                                      v         │
>>>> + *	                                     done <─────┘
>>>> + *
>>>> + */
>>>> +
>>>> +/*
>>>> + * Enum values for xfs_delattr_context.da_state
>>>> + *
>>>> + * These values are used by delayed attribute operations to keep track  of where
>>>> + * they were before they returned -EAGAIN.  A return code of -EAGAIN signals the
>>>> + * calling function to roll the transaction, and then recall the subroutine to
>>>> + * finish the operation.  The enum is then used by the subroutine to jump back
>>>> + * to where it was and resume executing where it left off.
>>>> + */
>>>> +enum xfs_delattr_state {
>>>> +	XFS_DAS_UNINIT		= 0,  /* No state has been set yet */
>>>> +	XFS_DAS_RM_SHRINK,	      /* We are shrinking the tree */
>>>> +};
>>>> +
>>>> +/*
>>>> + * Defines for xfs_delattr_context.flags
>>>> + */
>>>> +#define XFS_DAC_DEFER_FINISH		0x01 /* finish the transaction */
>>>> +#define XFS_DAC_NODE_RMVNAME_INIT	0x02 /* xfs_attr_node_removename init */
>>>> +
>>>> +/*
>>>> + * Context used for keeping track of delayed attribute operations
>>>> + */
>>>> +struct xfs_delattr_context {
>>>> +	struct xfs_da_args      *da_args;
>>>> +
>>>> +	/* Used in xfs_attr_node_removename to roll through removing blocks */
>>>> +	struct xfs_da_state     *da_state;
>>>> +
>>>> +	/* Used to keep track of current state of delayed operation */
>>>> +	unsigned int            flags;
>>>> +	enum xfs_delattr_state  dela_state;
>>>> +};
>>>> +
>>>>    /*========================================================================
>>>>     * Function prototypes for the kernel.
>>>>     *========================================================================*/
>>>> @@ -91,6 +159,10 @@ int xfs_attr_set(struct xfs_da_args *args);
>>>>    int xfs_attr_set_args(struct xfs_da_args *args);
>>>>    int xfs_has_attr(struct xfs_da_args *args);
>>>>    int xfs_attr_remove_args(struct xfs_da_args *args);
>>>> +int xfs_attr_remove_iter(struct xfs_delattr_context *dac);
>>>> +int xfs_attr_trans_roll(struct xfs_delattr_context *dac);
>>>>    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);
>>>>    
>>>>    #endif	/* __XFS_ATTR_H__ */
>>>> diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
>>>> index bb128db..338377e 100644
>>>> --- a/fs/xfs/libxfs/xfs_attr_leaf.c
>>>> +++ b/fs/xfs/libxfs/xfs_attr_leaf.c
>>>> @@ -19,8 +19,8 @@
>>>>    #include "xfs_bmap_btree.h"
>>>>    #include "xfs_bmap.h"
>>>>    #include "xfs_attr_sf.h"
>>>> -#include "xfs_attr_remote.h"
>>>>    #include "xfs_attr.h"
>>>> +#include "xfs_attr_remote.h"
>>>>    #include "xfs_attr_leaf.h"
>>>>    #include "xfs_error.h"
>>>>    #include "xfs_trace.h"
>>>> diff --git a/fs/xfs/libxfs/xfs_attr_remote.c b/fs/xfs/libxfs/xfs_attr_remote.c
>>>> index 48d8e9c..1426c15 100644
>>>> --- a/fs/xfs/libxfs/xfs_attr_remote.c
>>>> +++ b/fs/xfs/libxfs/xfs_attr_remote.c
>>>> @@ -674,10 +674,12 @@ xfs_attr_rmtval_invalidate(
>>>>     */
>>>>    int
>>>>    xfs_attr_rmtval_remove(
>>>> -	struct xfs_da_args      *args)
>>>> +	struct xfs_da_args		*args)
>>>>    {
>>>> -	int			error;
>>>> -	int			retval;
>>>> +	int				error;
>>>> +	struct xfs_delattr_context	dac  = {
>>>> +		.da_args	= args,
>>>> +	};
>>>>    
>>>>    	trace_xfs_attr_rmtval_remove(args);
>>>>    
>>>> @@ -685,19 +687,17 @@ xfs_attr_rmtval_remove(
>>>>    	 * Keep de-allocating extents until the remote-value region is gone.
>>>>    	 */
>>>>    	do {
>>>> -		retval = __xfs_attr_rmtval_remove(args);
>>>> -		if (retval && retval != -EAGAIN)
>>>> -			return retval;
>>>> +		error = __xfs_attr_rmtval_remove(&dac);
>>>> +		if (error != -EAGAIN)
>>>> +			break;
>>>>    
>>>> -		/*
>>>> -		 * Close out trans and start the next one in the chain.
>>>> -		 */
>>>> -		error = xfs_trans_roll_inode(&args->trans, args->dp);
>>>> +		error = xfs_attr_trans_roll(&dac);
>>>>    		if (error)
>>>>    			return error;
>>>> -	} while (retval == -EAGAIN);
>>>>    
>>>> -	return 0;
>>>> +	} while (true);
>>>> +
>>>> +	return error;
>>>>    }
>>>>    
>>>>    /*
>>>> @@ -707,9 +707,10 @@ xfs_attr_rmtval_remove(
>>>>     */
>>>>    int
>>>>    __xfs_attr_rmtval_remove(
>>>> -	struct xfs_da_args	*args)
>>>> +	struct xfs_delattr_context	*dac)
>>>>    {
>>>> -	int			error, done;
>>>> +	struct xfs_da_args		*args = dac->da_args;
>>>> +	int				error, done;
>>>>    
>>>>    	/*
>>>>    	 * Unmap value blocks for this attr.
>>>> @@ -719,12 +720,10 @@ __xfs_attr_rmtval_remove(
>>>>    	if (error)
>>>>    		return error;
>>>>    
>>>> -	error = xfs_defer_finish(&args->trans);
>>>> -	if (error)
>>>> -		return error;
>>>> -
>>>> -	if (!done)
>>>> +	if (!done) {
>>>> +		dac->flags |= XFS_DAC_DEFER_FINISH;
>>>>    		return -EAGAIN;
>>>> +	}
>>>>    
>>>>    	return error;
>>>>    }
>>>> diff --git a/fs/xfs/libxfs/xfs_attr_remote.h b/fs/xfs/libxfs/xfs_attr_remote.h
>>>> index 9eee615..002fd30 100644
>>>> --- a/fs/xfs/libxfs/xfs_attr_remote.h
>>>> +++ b/fs/xfs/libxfs/xfs_attr_remote.h
>>>> @@ -14,5 +14,5 @@ int xfs_attr_rmtval_remove(struct xfs_da_args *args);
>>>>    int xfs_attr_rmtval_stale(struct xfs_inode *ip, struct xfs_bmbt_irec *map,
>>>>    		xfs_buf_flags_t incore_flags);
>>>>    int xfs_attr_rmtval_invalidate(struct xfs_da_args *args);
>>>> -int __xfs_attr_rmtval_remove(struct xfs_da_args *args);
>>>> +int __xfs_attr_rmtval_remove(struct xfs_delattr_context *dac);
>>>>    #endif /* __XFS_ATTR_REMOTE_H__ */
>>>> diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c
>>>> index bfad669..aaa7e66 100644
>>>> --- a/fs/xfs/xfs_attr_inactive.c
>>>> +++ b/fs/xfs/xfs_attr_inactive.c
>>>> @@ -15,10 +15,10 @@
>>>>    #include "xfs_da_format.h"
>>>>    #include "xfs_da_btree.h"
>>>>    #include "xfs_inode.h"
>>>> +#include "xfs_attr.h"
>>>>    #include "xfs_attr_remote.h"
>>>>    #include "xfs_trans.h"
>>>>    #include "xfs_bmap.h"
>>>> -#include "xfs_attr.h"
>>>>    #include "xfs_attr_leaf.h"
>>>>    #include "xfs_quota.h"
>>>>    #include "xfs_dir2.h"
>>>>
>>>
>>>
>>
> 
>