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Subject[PATCH 21/80] staging: lustre: osc: allow to call brw_commit() multiple times
Date
From: Jinshan Xiong <jinshan.xiong@intel.com>

Sometimes the rq_commit_cb of BRW RPC can be called twice if that RPC
has already committed at reply time. This will cause inaccuracy of
unstable pages accounting and then assertion.

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3274
Reviewed-on: http://review.whamcloud.com/8215
Reviewed-by: Prakash Surya <surya1@llnl.gov>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
---
drivers/staging/lustre/lustre/osc/osc_cache.c | 19 ++++---------------
drivers/staging/lustre/lustre/osc/osc_request.c | 8 ++++----
2 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/drivers/staging/lustre/lustre/osc/osc_cache.c b/drivers/staging/lustre/lustre/osc/osc_cache.c
index 53b5d73..683b3c2 100644
--- a/drivers/staging/lustre/lustre/osc/osc_cache.c
+++ b/drivers/staging/lustre/lustre/osc/osc_cache.c
@@ -1875,11 +1875,6 @@ void osc_dec_unstable_pages(struct ptlrpc_request *req)
atomic_sub(page_count, &obd_unstable_pages);
LASSERT(atomic_read(&obd_unstable_pages) >= 0);

- spin_lock(&req->rq_lock);
- req->rq_committed = 1;
- req->rq_unstable = 0;
- spin_unlock(&req->rq_lock);
-
wake_up_all(&cli->cl_cache->ccc_unstable_waitq);
}

@@ -1909,27 +1904,21 @@ void osc_inc_unstable_pages(struct ptlrpc_request *req)
LASSERT(atomic_read(&obd_unstable_pages) >= 0);
atomic_add(page_count, &obd_unstable_pages);

- spin_lock(&req->rq_lock);
-
/*
* If the request has already been committed (i.e. brw_commit
* called via rq_commit_cb), we need to undo the unstable page
* increments we just performed because rq_commit_cb wont be
- * called again. Otherwise, just set the commit callback so the
- * unstable page accounting is properly updated when the request
- * is committed
+ * called again.
*/
- if (req->rq_committed) {
+ spin_lock(&req->rq_lock);
+ if (unlikely(req->rq_committed)) {
/* Drop lock before calling osc_dec_unstable_pages */
spin_unlock(&req->rq_lock);
osc_dec_unstable_pages(req);
- spin_lock(&req->rq_lock);
} else {
req->rq_unstable = 1;
- req->rq_commit_cb = osc_dec_unstable_pages;
+ spin_unlock(&req->rq_lock);
}
-
- spin_unlock(&req->rq_lock);
}

/* this must be called holding the loi list lock to give coverage to exit_cache,
diff --git a/drivers/staging/lustre/lustre/osc/osc_request.c b/drivers/staging/lustre/lustre/osc/osc_request.c
index 536b868..a2d948f 100644
--- a/drivers/staging/lustre/lustre/osc/osc_request.c
+++ b/drivers/staging/lustre/lustre/osc/osc_request.c
@@ -1847,21 +1847,21 @@ static int brw_interpret(const struct lu_env *env,

static void brw_commit(struct ptlrpc_request *req)
{
- spin_lock(&req->rq_lock);
/*
* If osc_inc_unstable_pages (via osc_extent_finish) races with
* this called via the rq_commit_cb, I need to ensure
* osc_dec_unstable_pages is still called. Otherwise unstable
* pages may be leaked.
*/
- if (req->rq_unstable) {
+ spin_lock(&req->rq_lock);
+ if (unlikely(req->rq_unstable)) {
+ req->rq_unstable = 0;
spin_unlock(&req->rq_lock);
osc_dec_unstable_pages(req);
- spin_lock(&req->rq_lock);
} else {
req->rq_committed = 1;
+ spin_unlock(&req->rq_lock);
}
- spin_unlock(&req->rq_lock);
}

/**
--
1.7.1
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