[PATCH 15/15] xfs: poll waiting for quotacheck

Darrick J. Wong
2019-06-26T20:45:44Z

Create a pwork destroy function that uses polling instead of
uninterruptible sleep to wait for work items to finish so that we can
touch the softlockup watchdog. IOWs, gross hack.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
fs/xfs/xfs_iwalk.c | 3 +++
fs/xfs/xfs_iwalk.h | 3 ++-
fs/xfs/xfs_pwork.c | 19 +++++++++++++++++++
fs/xfs/xfs_pwork.h | 3 +++
fs/xfs/xfs_qm.c | 2 +-
5 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_iwalk.c b/fs/xfs/xfs_iwalk.c
index f0277369e896..80c139aed264 100644
--- a/fs/xfs/xfs_iwalk.c
+++ b/fs/xfs/xfs_iwalk.c
@@ -588,6 +588,7 @@ xfs_iwalk_threaded(
xfs_ino_t startino,
xfs_iwalk_fn iwalk_fn,
unsigned int inode_records,
+ bool polled,
void *data)
{
struct xfs_pwork_ctl pctl;
@@ -619,6 +620,8 @@ xfs_iwalk_threaded(
startino = XFS_AGINO_TO_INO(mp, agno + 1, 0);
}

+ if (polled)
+ xfs_pwork_poll(&pctl);
return xfs_pwork_destroy(&pctl);
}

diff --git a/fs/xfs/xfs_iwalk.h b/fs/xfs/xfs_iwalk.h
index 22c31763a9b8..67462861680c 100644
--- a/fs/xfs/xfs_iwalk.h
+++ b/fs/xfs/xfs_iwalk.h
@@ -16,7 +16,8 @@ typedef int (*xfs_iwalk_fn)(struct xfs_mount *mp, struct xfs_trans *tp,
int xfs_iwalk(struct xfs_mount *mp, struct xfs_trans *tp, xfs_ino_t startino,
xfs_iwalk_fn iwalk_fn, unsigned int inode_records, void *data);
int xfs_iwalk_threaded(struct xfs_mount *mp, xfs_ino_t startino,
- xfs_iwalk_fn iwalk_fn, unsigned int inode_records, void *data);
+ xfs_iwalk_fn iwalk_fn, unsigned int inode_records, bool poll,
+ void *data);

/* Walk all inode btree records in the filesystem starting from @startino. */
typedef int (*xfs_inobt_walk_fn)(struct xfs_mount *mp, struct xfs_trans *tp,
diff --git a/fs/xfs/xfs_pwork.c b/fs/xfs/xfs_pwork.c
index 779596ed9432..562ace9d5eb8 100644
--- a/fs/xfs/xfs_pwork.c
+++ b/fs/xfs/xfs_pwork.c
@@ -13,6 +13,7 @@
#include "xfs_trace.h"
#include "xfs_sysctl.h"
#include "xfs_pwork.h"
+#include <linux/nmi.h>

/*
* Parallel Work Queue
@@ -46,6 +47,8 @@ xfs_pwork_work(
error = pctl->work_fn(pctl->mp, pwork);
if (error && !pctl->error)
pctl->error = error;
+ if (atomic_dec_and_test(&pctl->nr_work))
+ wake_up(&pctl->poll_wait);
}

/*
@@ -74,6 +77,8 @@ xfs_pwork_init(
pctl->work_fn = work_fn;
pctl->error = 0;
pctl->mp = mp;
+ atomic_set(&pctl->nr_work, 0);
+ init_waitqueue_head(&pctl->poll_wait);

return 0;
}
@@ -86,6 +91,7 @@ xfs_pwork_queue(
{
INIT_WORK(&pwork->work, xfs_pwork_work);
pwork->pctl = pctl;
+ atomic_inc(&pctl->nr_work);
queue_work(pctl->wq, &pwork->work);
}

@@ -99,6 +105,19 @@ xfs_pwork_destroy(
return pctl->error;
}

+/*
+ * Wait for the work to finish by polling completion status and touch the soft
+ * lockup watchdog. This is for callers such as mount which hold locks.
+ */
+void
+xfs_pwork_poll(
+ struct xfs_pwork_ctl *pctl)
+{
+ while (wait_event_timeout(pctl->poll_wait,
+ atomic_read(&pctl->nr_work) == 0, HZ) == 0)
+ touch_softlockup_watchdog();
+}
+
/*
* Return the amount of parallelism that the data device can handle, or 0 for
* no limit.
diff --git a/fs/xfs/xfs_pwork.h b/fs/xfs/xfs_pwork.h
index 99a9d210d49e..8133124cf3bb 100644
--- a/fs/xfs/xfs_pwork.h
+++ b/fs/xfs/xfs_pwork.h
@@ -18,6 +18,8 @@ struct xfs_pwork_ctl {
struct workqueue_struct *wq;
struct xfs_mount *mp;
xfs_pwork_work_fn work_fn;
+ struct wait_queue_head poll_wait;
+ atomic_t nr_work;
int error;
};

@@ -53,6 +55,7 @@ int xfs_pwork_init(struct xfs_mount *mp, struct xfs_pwork_ctl *pctl,
unsigned int nr_threads);
void xfs_pwork_queue(struct xfs_pwork_ctl *pctl, struct xfs_pwork *pwork);
int xfs_pwork_destroy(struct xfs_pwork_ctl *pctl);
+void xfs_pwork_poll(struct xfs_pwork_ctl *pctl);
unsigned int xfs_pwork_guess_datadev_parallelism(struct xfs_mount *mp);

#endif /* __XFS_PWORK_H__ */
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 8004c931c86e..8bb902125403 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -1304,7 +1304,7 @@ xfs_qm_quotacheck(
flags |= XFS_PQUOTA_CHKD;
}

- error = xfs_iwalk_threaded(mp, 0, xfs_qm_dqusage_adjust, 0, NULL);
+ error = xfs_iwalk_threaded(mp, 0, xfs_qm_dqusage_adjust, 0, true, NULL);
if (error)
goto error_return;