diff options
| author |   Lars Ellenberg <lars.ellenberg@linbit.com> | 2015-02-25 19:37:28 +0100 |
|---|---|---|
| committer |   Jens Axboe <axboe@fb.com> | 2015-11-25 09:22:01 -0700 |
| commit | 6434f404b43afa0cfe54fec009760510431ca103 (patch) | |
| tree | 3b5adfc83ae2fe16d028d1ec44db50bbe0cf93d1 /drivers/block/drbd | |
| parent | drbd: fix NULL deref in remember_new_state (diff) | |
| download | linux-dev-6434f404b43afa0cfe54fec009760510431ca103.tar.xz linux-dev-6434f404b43afa0cfe54fec009760510431ca103.zip | |
drbd: fix refcount error during detach of an already failed disk
A D_FAILED disk transitions as quickly as possible to
D_DISKLESS. But in the "unresponsive local disk" case,
there remains a time window where a administrative detach command could
find the disk already failed, but some internal meta data IO against the
unresponsive local disk still pending.
In that case, drbd_md_get_buffer() will return NULL.
Don't unconditionally call drbd_md_put_buffer(), or it will cause
refcount imbalance, and prevent any further re-attach on this volume
(until it is deleted and re-created).
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/block/drbd')
| -rw-r--r-- | drivers/block/drbd/drbd_nl.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 331b378b7d0b..79dc3d4f5aee 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -1915,6 +1915,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) static int adm_detach(struct drbd_device *device, int force) { enum drbd_state_rv retcode; + void *buffer; int ret; if (force) { @@ -1925,9 +1926,12 @@ static int adm_detach(struct drbd_device *device, int force) } drbd_suspend_io(device); /* so no-one is stuck in drbd_al_begin_io */ - drbd_md_get_buffer(device, __func__); /* make sure there is no in-flight meta-data IO */ - retcode = drbd_request_state(device, NS(disk, D_FAILED)); - drbd_md_put_buffer(device); + buffer = drbd_md_get_buffer(device, __func__); /* make sure there is no in-flight meta-data IO */ + if (buffer) { + retcode = drbd_request_state(device, NS(disk, D_FAILED)); + drbd_md_put_buffer(device); + } else /* already <= D_FAILED */ + retcode = SS_NOTHING_TO_DO; /* D_FAILED will transition to DISKLESS. */ drbd_resume_io(device); ret = wait_event_interruptible(device->misc_wait, |