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| author | Ilya Dryomov <idryomov@gmail.com> | 2023-08-01 19:14:24 +0200 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2023-08-02 09:07:34 +0200 |
| commit | 9d01e07fd1bfb4daae156ab528aa196f5ac2b2bc (patch) | |
| tree | 66dbdc030d34d249467716fbac8811ce93eef460 /drivers/block | |
| parent | e7e607bd00481745550389a29ecabe33e13d67cf (diff) | |
| download | linux-9d01e07fd1bfb4daae156ab528aa196f5ac2b2bc.tar.gz | |
rbd: prevent busy loop when requesting exclusive lock
Due to rbd_try_acquire_lock() effectively swallowing all but
EBLOCKLISTED error from rbd_try_lock() ("request lock anyway") and
rbd_request_lock() returning ETIMEDOUT error not only for an actual
notify timeout but also when the lock owner doesn't respond, a busy
loop inside of rbd_acquire_lock() between rbd_try_acquire_lock() and
rbd_request_lock() is possible.
Requesting the lock on EBUSY error (returned by get_lock_owner_info()
if an incompatible lock or invalid lock owner is detected) makes very
little sense. The same goes for ETIMEDOUT error (might pop up pretty
much anywhere if osd_request_timeout option is set) and many others.
Just fail I/O requests on rbd_dev->acquiring_list immediately on any
error from rbd_try_lock().
Cc: stable@vger.kernel.org # 588159009d5b: rbd: retrieve and check lock owner twice before blocklisting
Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/rbd.c | 28 |
1 files changed, 15 insertions, 13 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 24afcc93ac0126..2328cc05be36e9 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -3675,7 +3675,7 @@ static int rbd_lock(struct rbd_device *rbd_dev) ret = ceph_cls_lock(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc, RBD_LOCK_NAME, CEPH_CLS_LOCK_EXCLUSIVE, cookie, RBD_LOCK_TAG, "", 0); - if (ret) + if (ret && ret != -EEXIST) return ret; __rbd_lock(rbd_dev, cookie); @@ -3878,7 +3878,7 @@ static struct ceph_locker *get_lock_owner_info(struct rbd_device *rbd_dev) &rbd_dev->header_oloc, RBD_LOCK_NAME, &lock_type, &lock_tag, &lockers, &num_lockers); if (ret) { - rbd_warn(rbd_dev, "failed to retrieve lockers: %d", ret); + rbd_warn(rbd_dev, "failed to get header lockers: %d", ret); return ERR_PTR(ret); } @@ -3940,8 +3940,10 @@ static int find_watcher(struct rbd_device *rbd_dev, ret = ceph_osdc_list_watchers(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc, &watchers, &num_watchers); - if (ret) + if (ret) { + rbd_warn(rbd_dev, "failed to get watchers: %d", ret); return ret; + } sscanf(locker->id.cookie, RBD_LOCK_COOKIE_PREFIX " %llu", &cookie); for (i = 0; i < num_watchers; i++) { @@ -3985,8 +3987,12 @@ static int rbd_try_lock(struct rbd_device *rbd_dev) locker = refreshed_locker = NULL; ret = rbd_lock(rbd_dev); - if (ret != -EBUSY) + if (!ret) + goto out; + if (ret != -EBUSY) { + rbd_warn(rbd_dev, "failed to lock header: %d", ret); goto out; + } /* determine if the current lock holder is still alive */ locker = get_lock_owner_info(rbd_dev); @@ -4089,11 +4095,8 @@ static int rbd_try_acquire_lock(struct rbd_device *rbd_dev) ret = rbd_try_lock(rbd_dev); if (ret < 0) { - rbd_warn(rbd_dev, "failed to lock header: %d", ret); - if (ret == -EBLOCKLISTED) - goto out; - - ret = 1; /* request lock anyway */ + rbd_warn(rbd_dev, "failed to acquire lock: %d", ret); + goto out; } if (ret > 0) { up_write(&rbd_dev->lock_rwsem); @@ -6627,12 +6630,11 @@ static int rbd_add_acquire_lock(struct rbd_device *rbd_dev) cancel_delayed_work_sync(&rbd_dev->lock_dwork); if (!ret) ret = -ETIMEDOUT; - } - if (ret) { - rbd_warn(rbd_dev, "failed to acquire exclusive lock: %ld", ret); - return ret; + rbd_warn(rbd_dev, "failed to acquire lock: %ld", ret); } + if (ret) + return ret; /* * The lock may have been released by now, unless automatic lock |