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: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Darrick J. Wong 2023-04-11 18:59:55 -07:00
parent 00e7b3bac1
commit 9b2e5a234c
9 changed files with 22 additions and 20 deletions

View file

@ -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)

View file

@ -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 */

View file

@ -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;

View file

@ -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;
}

View file

@ -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;

View file

@ -460,10 +460,7 @@ xfs_rmapbt_init_common(
cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_rmap_2);
cur->bc_ops = &xfs_rmapbt_ops;
/* 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;
}

View file

@ -168,9 +168,7 @@ xfs_iunlink_log_inode(
iup->ip = ip;
iup->next_agino = next_agino;
iup->old_agino = ip->i_next_unlinked;
atomic_inc(&pag->pag_ref);
iup->pag = pag;
iup->pag = xfs_perag_hold(pag);
xfs_trans_add_item(tp, &iup->item);
tp->t_flags |= XFS_TRANS_DIRTY;

View file

@ -667,11 +667,10 @@ xfs_iwalk_threaded(
iwag->mp = mp;
/*
* perag is being handed off to async work, so take another
* perag is being handed off to async work, so take a passive
* reference for the async work to release.
*/
atomic_inc(&pag->pag_ref);
iwag->pag = pag;
iwag->pag = xfs_perag_hold(pag);
iwag->iwalk_fn = iwalk_fn;
iwag->data = data;
iwag->startino = startino;

View file

@ -190,6 +190,7 @@ DEFINE_EVENT(xfs_perag_class, name, \
TP_ARGS(pag, caller_ip))
DEFINE_PERAG_REF_EVENT(xfs_perag_get);
DEFINE_PERAG_REF_EVENT(xfs_perag_get_tag);
DEFINE_PERAG_REF_EVENT(xfs_perag_hold);
DEFINE_PERAG_REF_EVENT(xfs_perag_put);
DEFINE_PERAG_REF_EVENT(xfs_perag_grab);
DEFINE_PERAG_REF_EVENT(xfs_perag_grab_tag);