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dmu_objset_from_ds must be called with dp_config_rwlock held

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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
This commit is contained in:
Matthew Ahrens
2020-03-12 10:55:02 -07:00
committed by GitHub
parent fa130e010c
commit 0fdd6106bb
7 changed files with 101 additions and 115 deletions
Download Patch File Download Diff File Expand all files Collapse all files
module/zfs/dmu_send.c
+11 -30
View File
@@ -115,8 +115,7 @@ overflow_multiply(uint64_t a, uint64_t b, uint64_t *c)
struct send_thread_arg {
bqueue_t q;
dsl_dataset_t *ds; /* Dataset to traverse */
redaction_list_t *redaction_list;
objset_t *os; /* Objset to traverse */
uint64_t fromtxg; /* Traverse from this txg */
int flags; /* flags to pass to traverse_dataset */
int error_code;
@@ -1092,19 +1091,16 @@ send_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
ASSERT(zb->zb_object == DMU_META_DNODE_OBJECT ||
zb->zb_object >= sta->resume.zb_object);
ASSERT3P(sta->ds, !=, NULL);
/*
* All bps of an encrypted os should have the encryption bit set.
* If this is not true it indicates tampering and we report an error.
*/
objset_t *os;
VERIFY0(dmu_objset_from_ds(sta->ds, &os));
if (os->os_encrypted &&
if (sta->os->os_encrypted &&
!BP_IS_HOLE(bp) && !BP_USES_CRYPT(bp)) {
spa_log_error(spa, zb);
zfs_panic_recover("unencrypted block in encrypted "
"object set %llu", sta->ds->ds_object);
"object set %llu", dmu_objset_id(sta->os));
return (SET_ERROR(EIO));
}
@@ -1211,10 +1207,7 @@ redact_list_cb(redact_block_phys_t *rb, void *arg)
/*
* This function kicks off the traverse_dataset. It also handles setting the
* error code of the thread in case something goes wrong, and pushes the End of
* Stream record when the traverse_dataset call has finished. If there is no
* dataset to traverse, then we traverse the redaction list provided and enqueue
* records for that. If neither is provided, the thread immediately pushes an
* End of Stream marker.
* Stream record when the traverse_dataset call has finished.
*/
static void
send_traverse_thread(void *arg)
@@ -1224,20 +1217,9 @@ send_traverse_thread(void *arg)
struct send_range *data;
fstrans_cookie_t cookie = spl_fstrans_mark();
if (st_arg->ds != NULL) {
ASSERT3P(st_arg->redaction_list, ==, NULL);
err = traverse_dataset_resume(st_arg->ds,
st_arg->fromtxg, &st_arg->resume,
st_arg->flags, send_cb, st_arg);
} else if (st_arg->redaction_list != NULL) {
struct redact_list_cb_arg rlcba = {0};
rlcba.cancel = &st_arg->cancel;
rlcba.num_blocks_visited = st_arg->num_blocks_visited;
rlcba.q = &st_arg->q;
rlcba.mark_redact = B_FALSE;
err = dsl_redaction_list_traverse(st_arg->redaction_list,
&st_arg->resume, redact_list_cb, &rlcba);
}
err = traverse_dataset_resume(st_arg->os->os_dsl_dataset,
st_arg->fromtxg, &st_arg->resume,
st_arg->flags, send_cb, st_arg);
if (err != EINTR)
st_arg->error_code = err;
@@ -2029,7 +2011,7 @@ create_begin_record(struct dmu_send_params *dspp, objset_t *os,
}
static void
setup_to_thread(struct send_thread_arg *to_arg, dsl_dataset_t *to_ds,
setup_to_thread(struct send_thread_arg *to_arg, objset_t *to_os,
dmu_sendstatus_t *dssp, uint64_t fromtxg, boolean_t rawok)
{
VERIFY0(bqueue_init(&to_arg->q, zfs_send_no_prefetch_queue_ff,
@@ -2037,12 +2019,11 @@ setup_to_thread(struct send_thread_arg *to_arg, dsl_dataset_t *to_ds,
offsetof(struct send_range, ln)));
to_arg->error_code = 0;
to_arg->cancel = B_FALSE;
to_arg->ds = to_ds;
to_arg->os = to_os;
to_arg->fromtxg = fromtxg;
to_arg->flags = TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA;
if (rawok)
to_arg->flags |= TRAVERSE_NO_DECRYPT;
to_arg->redaction_list = NULL;
to_arg->num_blocks_visited = &dssp->dss_blocks;
(void) thread_create(NULL, 0, send_traverse_thread, to_arg, 0,
curproc, TS_RUN, minclsyspri);
@@ -2489,7 +2470,7 @@ dmu_send_impl(struct dmu_send_params *dspp)
nvlist_t *keynvl = NULL;
ASSERT(os->os_encrypted);
err = dsl_crypto_populate_key_nvlist(to_ds, ivset_guid,
err = dsl_crypto_populate_key_nvlist(os, ivset_guid,
&keynvl);
if (err != 0) {
fnvlist_free(nvl);
@@ -2513,7 +2494,7 @@ dmu_send_impl(struct dmu_send_params *dspp)
goto out;
}
setup_to_thread(to_arg, to_ds, dssp, fromtxg, dspp->rawok);
setup_to_thread(to_arg, os, dssp, fromtxg, dspp->rawok);
setup_from_thread(from_arg, from_rl, dssp);
setup_redact_list_thread(rlt_arg, dspp, redact_rl, dssp);
setup_merge_thread(smt_arg, dspp, from_arg, to_arg, rlt_arg, os);