Commit b7b2846f authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: add the ability to join a held buffer to a defer_ops 



In certain cases, defer_ops callers will lock a buffer and want to hold
the lock across transaction rolls.  Similar to ijoined inodes, we want
to dirty & join the buffer with each transaction roll in defer_finish so
that afterwards the caller still owns the buffer lock and we haven't
inadvertently pinned the log.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent b7e0b6ff

fs/xfs/libxfs/xfs_defer.c

+36 −3
Original line number Diff line number Diff line
@@ -249,6 +249,10 @@ xfs_defer_trans_roll( 
	for (i = 0; i < XFS_DEFER_OPS_NR_INODES && dop->dop_inodes[i]; i++)

		xfs_trans_log_inode(*tp, dop->dop_inodes[i], XFS_ILOG_CORE);



	/* Hold the (previously bjoin'd) buffer locked across the roll. */

	for (i = 0; i < XFS_DEFER_OPS_NR_BUFS && dop->dop_bufs[i]; i++)

		xfs_trans_dirty_buf(*tp, dop->dop_bufs[i]);



	trace_xfs_defer_trans_roll((*tp)->t_mountp, dop);



	/* Roll the transaction. */
@@ -264,6 +268,12 @@ xfs_defer_trans_roll( 
	for (i = 0; i < XFS_DEFER_OPS_NR_INODES && dop->dop_inodes[i]; i++)

		xfs_trans_ijoin(*tp, dop->dop_inodes[i], 0);



	/* Rejoin the buffers and dirty them so the log moves forward. */

	for (i = 0; i < XFS_DEFER_OPS_NR_BUFS && dop->dop_bufs[i]; i++) {

		xfs_trans_bjoin(*tp, dop->dop_bufs[i]);

		xfs_trans_bhold(*tp, dop->dop_bufs[i]);

	}



	return error;

}
@@ -295,6 +305,31 @@ xfs_defer_ijoin( 
		}

	}



	ASSERT(0);

	return -EFSCORRUPTED;

}



/*

 * Add this buffer to the deferred op.  Each joined buffer is relogged

 * each time we roll the transaction.

 */

int

xfs_defer_bjoin(

	struct xfs_defer_ops		*dop,

	struct xfs_buf			*bp)

{

	int				i;



	for (i = 0; i < XFS_DEFER_OPS_NR_BUFS; i++) {

		if (dop->dop_bufs[i] == bp)

			return 0;

		else if (dop->dop_bufs[i] == NULL) {

			dop->dop_bufs[i] = bp;

			return 0;

		}

	}



	ASSERT(0);

	return -EFSCORRUPTED;

}
@@ -493,9 +528,7 @@ xfs_defer_init( 
	struct xfs_defer_ops		*dop,

	xfs_fsblock_t			*fbp)

{

	dop->dop_committed = false;

	dop->dop_low = false;

	memset(&dop->dop_inodes, 0, sizeof(dop->dop_inodes));

	memset(dop, 0, sizeof(struct xfs_defer_ops));

	*fbp = NULLFSBLOCK;

	INIT_LIST_HEAD(&dop->dop_intake);

	INIT_LIST_HEAD(&dop->dop_pending);

fs/xfs/libxfs/xfs_defer.h

+4 −1
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ enum xfs_defer_ops_type { 
};



#define XFS_DEFER_OPS_NR_INODES	2	/* join up to two inodes */

#define XFS_DEFER_OPS_NR_BUFS	2	/* join up to two buffers */



struct xfs_defer_ops {

	bool			dop_committed;	/* did any trans commit? */
@@ -66,8 +67,9 @@ struct xfs_defer_ops { 
	struct list_head	dop_intake;	/* unlogged pending work */

	struct list_head	dop_pending;	/* logged pending work */



	/* relog these inodes with each roll */

	/* relog these with each roll */

	struct xfs_inode	*dop_inodes[XFS_DEFER_OPS_NR_INODES];

	struct xfs_buf		*dop_bufs[XFS_DEFER_OPS_NR_BUFS];

};



void xfs_defer_add(struct xfs_defer_ops *dop, enum xfs_defer_ops_type type,
@@ -77,6 +79,7 @@ void xfs_defer_cancel(struct xfs_defer_ops *dop); 
void xfs_defer_init(struct xfs_defer_ops *dop, xfs_fsblock_t *fbp);

bool xfs_defer_has_unfinished_work(struct xfs_defer_ops *dop);

int xfs_defer_ijoin(struct xfs_defer_ops *dop, struct xfs_inode *ip);

int xfs_defer_bjoin(struct xfs_defer_ops *dop, struct xfs_buf *bp);



/* Description of a deferred type. */

struct xfs_defer_op_type {

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