diff options
| author | Roman Kagan <rvkagan@yandex-team.ru> | 2021-01-29 10:38:59 +0300 |
|---|---|---|
| committer | Eric Blake <eblake@redhat.com> | 2021-02-03 08:17:12 -0600 |
| commit | 5082fc82a6bc3fc06a04be47d39777c7cff61e5b (patch) | |
| tree | 43d8289773e56056ba55e57d5d197d85e8445db9 | |
| parent | ddde5ee769fcc84b96f879d7b94f35268f69ca3b (diff) | |
nbd: make nbd_read* return -EIO on error
NBD reconnect logic considers the error code from the functions that
read NBD messages to tell if reconnect should be attempted or not: it is
attempted on -EIO, otherwise the client transitions to NBD_CLIENT_QUIT
state (see nbd_channel_error). This error code is propagated from the
primitives like nbd_read.
The problem, however, is that nbd_read itself turns every error into -1
rather than -EIO. As a result, if the NBD server happens to die while
sending the message, the client in QEMU receives less data than it
expects, considers it as a fatal error, and wouldn't attempt
reestablishing the connection.
Fix it by turning every negative return from qio_channel_read_all into
-EIO returned from nbd_read. Apparently that was the original behavior,
but got broken later. Also adjust nbd_readXX to follow.
Fixes: e6798f06a6 ("nbd: generalize usage of nbd_read")
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210129073859.683063-4-rvkagan@yandex-team.ru>
Signed-off-by: Eric Blake <eblake@redhat.com>
| -rw-r--r-- | include/block/nbd.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/include/block/nbd.h b/include/block/nbd.h index 4a52a43ef5..5f34d23bb0 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -364,7 +364,7 @@ static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size, if (desc) { error_prepend(errp, "Failed to read %s: ", desc); } - return -1; + return ret; } return 0; @@ -375,8 +375,9 @@ static inline int nbd_read##bits(QIOChannel *ioc, \ uint##bits##_t *val, \ const char *desc, Error **errp) \ { \ - if (nbd_read(ioc, val, sizeof(*val), desc, errp) < 0) { \ - return -1; \ + int ret = nbd_read(ioc, val, sizeof(*val), desc, errp); \ + if (ret < 0) { \ + return ret; \ } \ *val = be##bits##_to_cpu(*val); \ return 0; \ |