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 /module/os | |
| 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 'module/os')
| -rw-r--r-- | module/os/linux/zfs/zfs_vfsops.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/module/os/linux/zfs/zfs_vfsops.c b/module/os/linux/zfs/zfs_vfsops.c index 9ed6256e8..478e07862 100644 --- a/module/os/linux/zfs/zfs_vfsops.c +++ b/module/os/linux/zfs/zfs_vfsops.c @@ -1804,7 +1804,10 @@ zfs_resume_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds) objset_t *os; VERIFY3P(ds->ds_owner, ==, zfsvfs); VERIFY(dsl_dataset_long_held(ds)); + dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds)); + dsl_pool_config_enter(dp, FTAG); VERIFY0(dmu_objset_from_ds(ds, &os)); + dsl_pool_config_exit(dp, FTAG); err = zfsvfs_init(zfsvfs, os); if (err != 0) @@ -1895,7 +1898,10 @@ zfs_end_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds) objset_t *os; VERIFY3P(ds->ds_owner, ==, zfsvfs); VERIFY(dsl_dataset_long_held(ds)); + dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds)); + dsl_pool_config_enter(dp, FTAG); VERIFY0(dmu_objset_from_ds(ds, &os)); + dsl_pool_config_exit(dp, FTAG); zfsvfs->z_os = os; /* release the VOPs */ |