Re: [PATCH v14 04/15] xfs: Add delay ready attr remove routines

[Chandan Babu R <chandanrlinux@gmail.com>]

On Tue, 22 Dec 2020 08:41:49 -0700, Allison Henderson wrote:
> 
> On 12/22/20 12:22 AM, Chandan Babu R wrote:
> > On Fri, 18 Dec 2020 00:29:06 -0700, 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        | 218 +++++++++++++++++++++++++++++-----------
> >>   fs/xfs/libxfs/xfs_attr.h        | 100 ++++++++++++++++++
> >>   fs/xfs/libxfs/xfs_attr_leaf.c   |   2 +-
> >>   fs/xfs/libxfs/xfs_attr_remote.c |  48 +++++----
> >>   fs/xfs/libxfs/xfs_attr_remote.h |   2 +-
> >>   fs/xfs/xfs_attr_inactive.c      |   2 +-
> >>   6 files changed, 288 insertions(+), 84 deletions(-)
> >>
> >> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> >> index 1969b88..b6330f9 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 +264,34 @@ 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;
> >> +
> >> +	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;
> >> +	} else
> >> +		error = xfs_trans_roll_inode(&args->trans, args->dp);
> >> +
> >> +	return error;
> >> +}
> >> +
> >> +/*
> >>    * Set the attribute specified in @args.
> >>    */
> >>   int
> >> @@ -364,23 +392,58 @@ 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;
> >> +	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;
> >> +}
> >>   
> >> -	if (!xfs_inode_hasattr(dp)) {
> >> -		error = -ENOATTR;
> >> -	} else if (dp->i_afp->if_format == XFS_DINODE_FMT_LOCAL) {
> >> +/*
> >> + * 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 we are shrinking a node, resume shrink */
> >> +	if (dac->dela_state == XFS_DAS_RM_SHRINK)
> >> +		goto node;
> >> +
> >> +	if (!xfs_inode_hasattr(dp))
> >> +		return -ENOATTR;
> >> +
> >> +	if (dp->i_afp->if_format == XFS_DINODE_FMT_LOCAL) {
> >>   		ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
> >> -		error = 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_shortform_remove(args);
> >>   	}
> >>   
> >> -	return error;
> >> +	if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
> >> +		return xfs_attr_leaf_removename(args);
> >> +node:
> >> +	/* If we are not short form or leaf, then proceed to remove node */
> >> +	return  xfs_attr_node_removename_iter(dac);
> >>   }
> >>   
> >>   /*
> >> @@ -1178,10 +1241,11 @@ 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)
> >>   {
> > 
> > In xfs_attr_node_removename_setup(), if either of
> > xfs_attr_leaf_mark_incomplete() or xfs_attr_rmtval_invalidate() returns with a
> > non-zero value, the memory pointed to by dac->da_state is not freed. This
> > happens because the caller (i.e. xfs_attr_node_removename_iter()) checks for
> > the non-NULL value of its local variable "state" to actually free the
> > corresponding memory.
> > 
> Ok, for this one it think it makes more sense to put an extra free in 
> the helper rather than have the caller handle it.  Will fix.
> 
> Do you have a tool thats tracing this out, or is it just by hand? 
> Because if it's a tool, I should probably be using it too :-)
>

Unfortunately, I found this by reading through the code changes. Tools to
figure these out would be great to have since it would let us focus mostly on
the larger picture.

> Thanks!
> Allison
> 
> 
> >> -	int			error;
> >> +	struct xfs_da_args		*args = dac->da_args;
> >> +	struct xfs_da_state		**state = &dac->da_state;
> >> +	int				error;
> >>   
> >>   	error = xfs_attr_node_hasname(args, state);
> >>   	if (error != -EEXIST)
> >> @@ -1203,13 +1267,16 @@ 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;
> >>   
> >> @@ -1240,28 +1307,34 @@ xfs_attr_node_remove_cleanup(
> >>   }
> >>   
> >>   /*
> >> - * 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)
> >>   {
> >> -	int			error;
> >> -	struct xfs_inode	*dp = args->dp;
> >> -
> >> -
> >> +	struct xfs_da_args		*args = dac->da_args;
> >> +	struct xfs_da_state		*state = dac->da_state;
> >> +	int				error = 0;
> >>   	/*
> >>   	 * If there is an out-of-line value, de-allocate the blocks.
> >>   	 * This is done before we remove the attribute so that we don't
> >>   	 * 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;
> >>   	}
> >> @@ -1274,51 +1347,74 @@ xfs_attr_node_remove_step(
> >>    *
> >>    * This routine will find the blocks of the name to remove, remove them and
> >>    * shrink 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 = NULL;
> >> -	int			retval, error;
> >> -	struct xfs_inode	*dp = args->dp;
> >> +	struct xfs_da_args		*args = dac->da_args;
> >> +	struct xfs_da_state		*state = NULL;
> >> +	int				retval, error;
> >> +	struct xfs_inode		*dp = args->dp;
> >>   
> >>   	trace_xfs_attr_node_removename(args);
> >>   
> >> -	error = xfs_attr_node_removename_setup(args, &state);
> >> -	if (error)
> >> -		goto out;
> >> +	if (!dac->da_state) {
> >> +		error = xfs_attr_node_removename_setup(dac);
> >> +		if (error)
> >> +			goto out;
> >> +	}
> >> +	state = dac->da_state;
> >>   
> >> -	error = xfs_attr_node_remove_step(args, state);
> >> -	if (error)
> >> -		goto out;
> >> +	switch (dac->dela_state) {
> >> +	case XFS_DAS_UNINIT:
> >> +		/*
> >> +		 * repeatedly remove remote blocks, remove the entry and join.
> >> +		 * returns -EAGAIN or 0 for completion of the step.
> >> +		 */
> >> +		error = xfs_attr_node_remove_step(dac);
> >> +		if (error)
> >> +			break;
> >>   
> >> -	retval = xfs_attr_node_remove_cleanup(args, state);
> >> +		retval = xfs_attr_node_remove_cleanup(args, state);
> >>   
> >> -	/*
> >> -	 * Check to see if the tree needs to be collapsed.
> >> -	 */
> >> -	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.
> >> +		 * Check to see if the tree needs to be collapsed. Set the flag
> >> +		 * to indicate that the calling function needs to move the
> >> +		 * shrink operation
> >>   		 */
> >> -		error = xfs_trans_roll_inode(&args->trans, dp);
> >> -		if (error)
> >> -			return error;
> >> -	}
> >> +		if (retval && (state->path.active > 1)) {
> >> +			error = xfs_da3_join(state);
> >> +			if (error)
> >> +				return error;
> >>   
> >> -	/*
> >> -	 * 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);
> >> +			dac->flags |= XFS_DAC_DEFER_FINISH;
> >> +			dac->dela_state = XFS_DAS_RM_SHRINK;
> >> +			return -EAGAIN;
> >> +		}
> >> +
> >> +		/* fallthrough */
> >> +	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);
> >> +		error = -EINVAL;
> >> +		goto out;
> >> +	}
> >>   
> >> +	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..3154ef4 100644
> >> --- a/fs/xfs/libxfs/xfs_attr.h
> >> +++ b/fs/xfs/libxfs/xfs_attr.h
> >> @@ -74,6 +74,102 @@ 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()
> >> + *              │
> >> + *              v
> >> + *        found attr blks? ───n──┐
> >> + *              │                v
> >> + *              │         find and invalidate
> >> + *              y         the blocks. mark
> >> + *              │         attr incomplete
> >> + *              ├────────────────┘
> >> + *              │
> >> + *              v
> >> + *      remove a block with
> >> + *    xfs_attr_node_remove_step <────┐
> >> + *              │                    │
> >> + *              v                    │
> >> + *      still have blks ──y──> return -EAGAIN.
> >> + *        to remove?          re-enter with one
> >> + *              │            less blk to remove
> >> + *              n
> >> + *              │
> >> + *              v
> >> + *       remove leaf and
> >> + *       update hash with
> >> + *   xfs_attr_node_remove_cleanup
> >> + *              │
> >> + *              v
> >> + *           need to
> >> + *        shrink tree? ─n─┐
> >> + *              │         │
> >> + *              y         │
> >> + *              │         │
> >> + *              v         │
> >> + *          join leaf     │
> >> + *              │         │
> >> + *              v         │
> >> + *      XFS_DAS_RM_SHRINK │
> >> + *              │         │
> >> + *              v         │
> >> + *       do the shrink    │
> >> + *              │         │
> >> + *              v         │
> >> + *          free state <──┘
> >> + *              │
> >> + *              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 */
> >> +
> >> +/*
> >> + * 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 +187,10 @@ 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 d6ef69a..3780141 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..f09820c 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);
> >>   
> >> @@ -685,31 +687,29 @@ 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);
> >> +	} while (true);
> >>   
> >> -	return 0;
> >> +	return error;
> >>   }
> >>   
> >>   /*
> >>    * Remove the value associated with an attribute by deleting the out-of-line
> >> - * buffer that it is stored on. Returns EAGAIN for the caller to refresh the
> >> + * buffer that it is stored on. Returns -EAGAIN for the caller to refresh the
> >>    * transaction and re-call the function
> >>    */
> >>   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 +719,20 @@ __xfs_attr_rmtval_remove(
> >>   	if (error)
> >>   		return error;
> >>   
> >> -	error = xfs_defer_finish(&args->trans);
> >> -	if (error)
> >> -		return error;
> >> -
> >> -	if (!done)
> >> +	/*
> >> +	 * We dont need an explicit state here to pick up where we left off.  We
> >> +	 * can figure it out using the !done return code.  Calling function only
> >> +	 * needs to keep recalling this routine until we indicate to stop by
> >> +	 * returning anything other than -EAGAIN. The actual value of
> >> +	 * attr->xattri_dela_state may be some value reminicent of the calling
> >> +	 * function, but it's value is irrelevant with in the context of this
> >> +	 * function.  Once we are done here, the next state is set as needed
> >> +	 * by the parent
> >> +	 */
> >> +	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"
> >>
> > 
> > 
> 


-- 
chandan