diff options
author | Matthew Ahrens <[email protected]> | 2020-03-12 10:55:02 -0700 |
---|---|---|
committer | GitHub <[email protected]> | 2020-03-12 10:55:02 -0700 |
commit | 0fdd6106bbd1b31322be87fee94c0c579ca459e6 (patch) | |
tree | 4568d0acc057501685d7eddbeadeb7f6ccfb7d42 /include/sys/zvol.h | |
parent | fa130e010c2ff9b33aba11d2699b667e454b3ccb (diff) |
dmu_objset_from_ds must be called with dp_config_rwlock held
The normal lock order is that the dp_config_rwlock must be held before
the ds_opening_lock. For example, dmu_objset_hold() does this.
However, dmu_objset_open_impl() is called with the ds_opening_lock held,
and if the dp_config_rwlock is not already held, it will attempt to
acquire it. This may lead to deadlock, since the lock order is
reversed.
Looking at all the callers of dmu_objset_open_impl() (which is
principally the callers of dmu_objset_from_ds()), almost all callers
already have the dp_config_rwlock. However, there are a few places in
the send and receive code paths that do not. For example:
dsl_crypto_populate_key_nvlist, send_cb, dmu_recv_stream,
receive_write_byref, redact_traverse_thread.
This commit resolves the problem by requiring all callers ot
dmu_objset_from_ds() to hold the dp_config_rwlock. In most cases, the
code has been restructured such that we call dmu_objset_from_ds()
earlier on in the send and receive processes, when we already have the
dp_config_rwlock, and save the objset_t until we need it in the middle
of the send or receive (similar to what we already do with the
dsl_dataset_t). Thus we do not need to acquire the dp_config_rwlock in
many new places.
I also cleaned up code in dmu_redact_snap() and send_traverse_thread().
Reviewed-by: Paul Dagnelie <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Paul Zuchowski <[email protected]>
Signed-off-by: Matthew Ahrens <[email protected]>
Closes #9662
Closes #10115
Diffstat (limited to 'include/sys/zvol.h')
0 files changed, 0 insertions, 0 deletions