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From: David Sterba <dsterba@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: anand.jain@oracle.com, David Sterba <dsterba@suse.com>
Subject: [PATCH] btrfs: scrub: add assertions for worker pointers
Date: Tue, 12 Feb 2019 18:15:40 +0100
Message-ID: <20190212171540.11518-1-dsterba@suse.com> (raw)
In-Reply-To: <1548830702-14676-1-git-send-email-anand.jain@oracle.com>

The scrub worker pointers are not NULL iff the scrub is running, so
reset them back once the last reference is dropped. Add assertions to
the initial phase of scrub to verify that.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/ctree.h | 4 ++++
 fs/btrfs/scrub.c | 7 +++++++
 2 files changed, 11 insertions(+)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 7efa1edb30cd..f92f97304e69 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1075,6 +1075,10 @@ struct btrfs_fs_info {
 	atomic_t scrubs_paused;
 	atomic_t scrub_cancel_req;
 	wait_queue_head_t scrub_pause_wait;
+	/*
+	 * The worker pointers are NULL iff the refcount is 0, ie. scrub is not
+	 * running.
+	 */
 	refcount_t scrub_workers_refcnt;
 	struct btrfs_workqueue *scrub_workers;
 	struct btrfs_workqueue *scrub_wr_completion_workers;
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index d20150d68a90..669bedfec4a9 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3744,17 +3744,20 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
 	lockdep_assert_held(&fs_info->scrub_lock);
 
 	if (refcount_read(&fs_info->scrub_workers_refcnt) == 0) {
+		ASSERT(fs_info->scrub_workers == NULL);
 		fs_info->scrub_workers = btrfs_alloc_workqueue(fs_info, "scrub",
 				flags, is_dev_replace ? 1 : max_active, 4);
 		if (!fs_info->scrub_workers)
 			goto fail_scrub_workers;
 
+		ASSERT(fs_info->scrub_wr_completion_workers == NULL);
 		fs_info->scrub_wr_completion_workers =
 			btrfs_alloc_workqueue(fs_info, "scrubwrc", flags,
 					      max_active, 2);
 		if (!fs_info->scrub_wr_completion_workers)
 			goto fail_scrub_wr_completion_workers;
 
+		ASSERT(fs_info->scrub_parity_workers == NULL);
 		fs_info->scrub_parity_workers =
 			btrfs_alloc_workqueue(fs_info, "scrubparity", flags,
 					      max_active, 2);
@@ -3934,6 +3937,10 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
 		scrub_workers = fs_info->scrub_workers;
 		scrub_wr_comp = fs_info->scrub_wr_completion_workers;
 		scrub_parity = fs_info->scrub_parity_workers;
+
+		fs_info->scrub_workers = NULL;
+		fs_info->scrub_wr_completion_workers = NULL;
+		fs_info->scrub_parity_workers = NULL;
 	}
 	mutex_unlock(&fs_info->scrub_lock);
 
-- 
2.20.1


  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-30  6:44 [PATCH v4 0/3] btrfs: scrub: fix scrub_lock Anand Jain
2019-01-30  6:45 ` [PATCH v4 1/3] btrfs: scrub: fix circular locking dependency warning Anand Jain
2019-01-30 14:07   ` David Sterba
2019-01-31  6:34     ` Anand Jain
2019-02-12 15:49       ` David Sterba
2019-02-12 16:45   ` David Sterba
2019-02-13 16:02     ` Anand Jain
2019-01-30  6:45 ` [PATCH v4 2/3] btrfs: scrub: add scrub_lock lockdep check in scrub_workers_get Anand Jain
2019-01-30  6:45 ` [PATCH v4 3/3] btrfs: scrub: convert scrub_workers_refcnt to refcount_t Anand Jain
2019-02-08 17:02 ` [PATCH v4 0/3] btrfs: scrub: fix scrub_lock David Sterba
2019-02-11  8:09   ` Anand Jain
2019-02-11  8:38 ` [PATCH v5 3/3] btrfs: scrub: convert scrub_workers_refcnt to refcount_t Anand Jain
2019-02-12 17:15 ` David Sterba [this message]
2019-02-13 16:02   ` [PATCH] btrfs: scrub: add assertions for worker pointers Anand Jain
2019-02-13 17:35 ` [PATCH v4 0/3] btrfs: scrub: fix scrub_lock David Sterba

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