diff options
| -rw-r--r-- | drivers/block/rbd.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 978e4d846f64..c5a56133c260 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -1850,6 +1850,17 @@ static u8 rbd_object_map_get(struct rbd_device *rbd_dev, u64 objno) static bool use_object_map(struct rbd_device *rbd_dev) { + /* + * An image mapped read-only can't use the object map -- it isn't + * loaded because the header lock isn't acquired. Someone else can + * write to the image and update the object map behind our back. + * + * A snapshot can't be written to, so using the object map is always + * safe. + */ + if (!rbd_is_snap(rbd_dev) && rbd_is_ro(rbd_dev)) + return false; + return ((rbd_dev->header.features & RBD_FEATURE_OBJECT_MAP) && !(rbd_dev->object_map_flags & RBD_FLAG_OBJECT_MAP_INVALID)); } @@ -3573,7 +3584,7 @@ static bool need_exclusive_lock(struct rbd_img_request *img_req) if (!(rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK)) return false; - if (rbd_is_snap(rbd_dev)) + if (rbd_is_ro(rbd_dev)) return false; rbd_assert(!test_bit(IMG_REQ_CHILD, &img_req->flags)); @@ -6653,7 +6664,7 @@ static int rbd_add_acquire_lock(struct rbd_device *rbd_dev) return -EINVAL; } - if (rbd_is_snap(rbd_dev)) + if (rbd_is_ro(rbd_dev)) return 0; rbd_assert(!rbd_is_lock_owner(rbd_dev)); |