4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hou Tao <houtao1@xxxxxxxxxx>
commit 75294442d896f2767be34f75aca7cc2b0d01301f upstream.
Now both check_for_space() and do_no_space_timeout() will read & write
pool->pf.error_if_no_space. If these functions run concurrently, as
shown in the following case, the default setting of "queue_if_no_space"
can get lost.
precondition:
* error_if_no_space = false (aka "queue_if_no_space")
* pool is in Out-of-Data-Space (OODS) mode
* no_space_timeout worker has been queued
CPU 0: CPU 1:
// delete a thin device
process_delete_mesg()
// check_for_space() invoked by commit()
set_pool_mode(pool, PM_WRITE)
pool->pf.error_if_no_space = \
pt->requested_pf.error_if_no_space
// timeout, pool is still in OODS mode
do_no_space_timeout
// "queue_if_no_space" config is lost
pool->pf.error_if_no_space = true
pool->pf.mode = new_mode
Fix it by stopping no_space_timeout worker when switching to write mode.
Fixes: bcc696fac11f ("dm thin: stay in out-of-data-space mode once no_space_timeout expires")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-thin.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -2518,6 +2518,8 @@ static void set_pool_mode(struct pool *p
case PM_WRITE:
if (old_mode != new_mode)
notify_of_pool_mode_change(pool, "write");
+ if (old_mode == PM_OUT_OF_DATA_SPACE)
+ cancel_delayed_work_sync(&pool->no_space_timeout);
pool->out_of_data_space = false;
pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space;
dm_pool_metadata_read_write(pool->pmd);
