diff options
| author | NeilBrown <neilb@suse.com> | 2017-06-05 16:49:39 +1000 |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2017-06-13 10:18:01 -0700 |
| commit | cc27b0c78c79680d128dbac79de0d40556d041bb (patch) | |
| tree | 1f32d4acd29d825eecc1aef90d423cdacea8121c /drivers/md/md.h | |
| parent | 63f700aab4c11d46626de3cd051dae56cf7e9056 (diff) | |
md: fix deadlock between mddev_suspend() and md_write_start()
If mddev_suspend() races with md_write_start() we can deadlock
with mddev_suspend() waiting for the request that is currently
in md_write_start() to complete the ->make_request() call,
and md_write_start() waiting for the metadata to be updated
to mark the array as 'dirty'.
As metadata updates done by md_check_recovery() only happen then
the mddev_lock() can be claimed, and as mddev_suspend() is often
called with the lock held, these threads wait indefinitely for each
other.
We fix this by having md_write_start() abort if mddev_suspend()
is happening, and ->make_request() aborts if md_write_start()
aborted.
md_make_request() can detect this abort, decrease the ->active_io
count, and wait for mddev_suspend().
Reported-by: Nix <nix@esperi.org.uk>
Fix: 68866e425be2(MD: no sync IO while suspended)
Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/md.h')
| -rw-r--r-- | drivers/md/md.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/md.h b/drivers/md/md.h index 0fa1de42c42b..63d342d560b8 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -510,7 +510,7 @@ struct md_personality int level; struct list_head list; struct module *owner; - void (*make_request)(struct mddev *mddev, struct bio *bio); + bool (*make_request)(struct mddev *mddev, struct bio *bio); int (*run)(struct mddev *mddev); void (*free)(struct mddev *mddev, void *priv); void (*status)(struct seq_file *seq, struct mddev *mddev); @@ -649,7 +649,7 @@ extern void md_wakeup_thread(struct md_thread *thread); extern void md_check_recovery(struct mddev *mddev); extern void md_reap_sync_thread(struct mddev *mddev); extern int mddev_init_writes_pending(struct mddev *mddev); -extern void md_write_start(struct mddev *mddev, struct bio *bi); +extern bool md_write_start(struct mddev *mddev, struct bio *bi); extern void md_write_inc(struct mddev *mddev, struct bio *bi); extern void md_write_end(struct mddev *mddev); extern void md_done_sync(struct mddev *mddev, int blocks, int ok); |