dm: report suspended device during destroy
commit5.4-rM2-2.2.x-imx-squashedadc0daad36
upstream. The function dm_suspended returns true if the target is suspended. However, when the target is being suspended during unload, it returns false. An example where this is a problem: the test "!dm_suspended(wc->ti)" in writecache_writeback is not sufficient, because dm_suspended returns zero while writecache_suspend is in progress. As is, without an enhanced dm_suspended, simply switching from flush_workqueue to drain_workqueue still emits warnings: workqueue writecache-writeback: drain_workqueue() isn't complete after 10 tries workqueue writecache-writeback: drain_workqueue() isn't complete after 100 tries workqueue writecache-writeback: drain_workqueue() isn't complete after 200 tries workqueue writecache-writeback: drain_workqueue() isn't complete after 300 tries workqueue writecache-writeback: drain_workqueue() isn't complete after 400 tries writecache_suspend calls flush_workqueue(wc->writeback_wq) - this function flushes the current work. However, the workqueue may re-queue itself and flush_workqueue doesn't wait for re-queued works to finish. Because of this - the function writecache_writeback continues execution after the device was suspended and then concurrently with writecache_dtr, causing a crash in writecache_writeback. We must use drain_workqueue - that waits until the work and all re-queued works finish. As a prereq for switching to drain_workqueue, this commit fixes dm_suspended to return true after the presuspend hook and before the postsuspend hook - just like during a normal suspend. It allows simplifying the dm-integrity and dm-writecache targets so that they don't have to maintain suspended flags on their own. With this change use of drain_workqueue() can be used effectively. This change was tested with the lvm2 testsuite and cryptsetup testsuite and the are no regressions. Fixes:48debafe4f
("dm: add writecache target") Cc: stable@vger.kernel.org # 4.18+ Reported-by: Corey Marthaler <cmarthal@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parent
e600edc7d8
commit
86543852e4
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@ -199,12 +199,13 @@ struct dm_integrity_c {
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__u8 log2_blocks_per_bitmap_bit;
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unsigned char mode;
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int suspending;
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int failed;
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struct crypto_shash *internal_hash;
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struct dm_target *ti;
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/* these variables are locked with endio_wait.lock */
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struct rb_root in_progress;
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struct list_head wait_list;
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@ -2311,7 +2312,7 @@ static void integrity_writer(struct work_struct *w)
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unsigned prev_free_sectors;
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/* the following test is not needed, but it tests the replay code */
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if (READ_ONCE(ic->suspending) && !ic->meta_dev)
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if (unlikely(dm_suspended(ic->ti)) && !ic->meta_dev)
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return;
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spin_lock_irq(&ic->endio_wait.lock);
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@ -2372,7 +2373,7 @@ static void integrity_recalc(struct work_struct *w)
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next_chunk:
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if (unlikely(READ_ONCE(ic->suspending)))
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if (unlikely(dm_suspended(ic->ti)))
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goto unlock_ret;
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range.logical_sector = le64_to_cpu(ic->sb->recalc_sector);
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@ -2800,8 +2801,6 @@ static void dm_integrity_postsuspend(struct dm_target *ti)
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del_timer_sync(&ic->autocommit_timer);
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WRITE_ONCE(ic->suspending, 1);
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if (ic->recalc_wq)
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drain_workqueue(ic->recalc_wq);
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@ -2830,8 +2829,6 @@ static void dm_integrity_postsuspend(struct dm_target *ti)
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#endif
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}
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WRITE_ONCE(ic->suspending, 0);
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BUG_ON(!RB_EMPTY_ROOT(&ic->in_progress));
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ic->journal_uptodate = true;
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@ -3615,6 +3612,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
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}
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ti->private = ic;
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ti->per_io_data_size = sizeof(struct dm_integrity_io);
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ic->ti = ti;
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ic->in_progress = RB_ROOT;
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INIT_LIST_HEAD(&ic->wait_list);
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@ -838,7 +838,7 @@ static void writecache_suspend(struct dm_target *ti)
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}
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wc_unlock(wc);
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flush_workqueue(wc->writeback_wq);
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drain_workqueue(wc->writeback_wq);
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wc_lock(wc);
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if (flush_on_suspend)
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@ -2389,6 +2389,7 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
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map = dm_get_live_table(md, &srcu_idx);
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if (!dm_suspended_md(md)) {
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dm_table_presuspend_targets(map);
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set_bit(DMF_SUSPENDED, &md->flags);
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dm_table_postsuspend_targets(map);
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}
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/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
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