mirror_zfs/module
Matthew Ahrens 0fdd6106bb
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 <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Paul Zuchowski <pzuchowski@datto.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #9662
Closes #10115
2020-03-12 10:55:02 -07:00
..
avl Wrap Linux module macros 2019-11-01 10:41:03 -07:00
icp Fix icp include directories for in-tree build 2020-02-20 08:10:47 -08:00
lua cppcheck: (error) Address of local auto-variable assigned 2019-12-18 17:25:42 -08:00
nvpair cppcheck: (warning) Possible null pointer dereference: nvh 2019-12-18 17:25:57 -08:00
os dmu_objset_from_ds must be called with dp_config_rwlock held 2020-03-12 10:55:02 -07:00
spl OpenZFS restructuring - move platform specific sources 2019-09-06 11:26:26 -07:00
unicode Wrap Linux module macros 2019-11-01 10:41:03 -07:00
zcommon Change default to overlay=on 2020-03-06 09:28:19 -08:00
zfs dmu_objset_from_ds must be called with dp_config_rwlock held 2020-03-12 10:55:02 -07:00
.gitignore Adapt gitignore for modules 2019-12-02 13:23:47 -08:00
Makefile.in module/Makefile.in: don't run xargs if empty 2019-10-08 10:10:23 -07:00