Commit 9b2e5a23 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: create traced helper to get extra perag references 



There are a few places in the XFS codebase where a caller has either an
active or a passive reference to a perag structure and wants to give
a passive reference to some other piece of code.  Btree cursor creation
and inode walks are good examples of this.  Replace the open-coded logic
with a helper to do this.

The new function adds a few safeguards -- it checks that there's at
least one reference to the perag structure passed in, and it records the
refcount bump in the ftrace information.  This makes it much easier to
debug perag refcounting problems.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
parent 00e7b3ba

fs/xfs/libxfs/xfs_ag.c

+13 −0
Original line number Diff line number Diff line
@@ -81,6 +81,19 @@ xfs_perag_get_tag( 
	return pag;

}



/* Get a passive reference to the given perag. */

struct xfs_perag *

xfs_perag_hold(

	struct xfs_perag	*pag)

{

	ASSERT(atomic_read(&pag->pag_ref) > 0 ||

	       atomic_read(&pag->pag_active_ref) > 0);



	trace_xfs_perag_hold(pag, _RET_IP_);

	atomic_inc(&pag->pag_ref);

	return pag;

}



void

xfs_perag_put(

	struct xfs_perag	*pag)

fs/xfs/libxfs/xfs_ag.h

+1 −0
Original line number Diff line number Diff line
@@ -134,6 +134,7 @@ void xfs_free_perag(struct xfs_mount *mp); 
struct xfs_perag *xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno);

struct xfs_perag *xfs_perag_get_tag(struct xfs_mount *mp, xfs_agnumber_t agno,

		unsigned int tag);

struct xfs_perag *xfs_perag_hold(struct xfs_perag *pag);

void xfs_perag_put(struct xfs_perag *pag);



/* Active AG references */

fs/xfs/libxfs/xfs_alloc_btree.c

+1 −3
Original line number Diff line number Diff line
@@ -492,9 +492,7 @@ xfs_allocbt_init_common( 
		cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_abtb_2);

	}



	/* take a reference for the cursor */

	atomic_inc(&pag->pag_ref);

	cur->bc_ag.pag = pag;

	cur->bc_ag.pag = xfs_perag_hold(pag);



	if (xfs_has_crc(mp))

		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;

fs/xfs/libxfs/xfs_ialloc_btree.c

+1 −3
Original line number Diff line number Diff line
@@ -450,9 +450,7 @@ xfs_inobt_init_common( 
	if (xfs_has_crc(mp))

		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;



	/* take a reference for the cursor */

	atomic_inc(&pag->pag_ref);

	cur->bc_ag.pag = pag;

	cur->bc_ag.pag = xfs_perag_hold(pag);

	return cur;

}

fs/xfs/libxfs/xfs_refcount_btree.c

+1 −4
Original line number Diff line number Diff line
@@ -340,10 +340,7 @@ xfs_refcountbt_init_common( 


	cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;



	/* take a reference for the cursor */

	atomic_inc(&pag->pag_ref);

	cur->bc_ag.pag = pag;



	cur->bc_ag.pag = xfs_perag_hold(pag);

	cur->bc_ag.refc.nr_ops = 0;

	cur->bc_ag.refc.shape_changes = 0;

	cur->bc_ops = &xfs_refcountbt_ops;