nbd: Use invalidate_disk() helper on disconnect

When a nbd device encounters a writeback error, that error will
get propagated to the bd_inode's wb_err field. Then if this nbd
device's backend is disconnected and another is attached, we will
get back the previous writeback error on fsync, which is unexpected.

To fix it, let's use invalidate_disk() helper to invalidate the
disk on disconnect instead of just setting disk's capacity to zero.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210922123711.187-5-xieyongji@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 1183f7872b7134f154d8a6f6827e3b4e1fcffb90..8922b8864487feb65af749544567a38c7839bde1 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -310,14 +310,6 @@ static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
        nsock->sent = 0;
 }
 
-static void nbd_size_clear(struct nbd_device *nbd)
-{
-       if (nbd->config->bytesize) {
-               set_capacity(nbd->disk, 0);
-               kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
-       }
-}
-
 static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
                loff_t blksize)
 {
@@ -1237,7 +1229,9 @@ static void nbd_config_put(struct nbd_device *nbd)
                                        &nbd->config_lock)) {
                struct nbd_config *config = nbd->config;
                nbd_dev_dbg_close(nbd);
-               nbd_size_clear(nbd);
+               invalidate_disk(nbd->disk);
+               if (nbd->config->bytesize)
+                       kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
                if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
                                       &config->runtime_flags))
                        device_remove_file(disk_to_dev(nbd->disk), &pid_attr);