Hello Kent Overstreet,
The patch 2d69588454f4: "bcachefs: Erasure coding" from Nov 1, 2018
(linux-next), leads to the following Smatch static checker warning:
fs/bcachefs/alloc_foreground.c:1056 should_drop_bucket()
warn: sleeping in atomic context
The call tree is:
bch2_open_buckets_stop() <- disables preempt
-> should_drop_bucket()
fs/bcachefs/alloc_foreground.c
1114 spin_lock(&c->freelist_lock);
Preempt disabled
1115 i = 0;
1116 while (i < c->open_buckets_partial_nr) {
1117 struct open_bucket *ob =
1118 c->open_buckets + c->open_buckets_partial[i];
1119
1120 if (should_drop_bucket(ob, c, ca, ec)) {
Called
1121 --c->open_buckets_partial_nr;
1122 swap(c->open_buckets_partial[i],
1123
c->open_buckets_partial[c->open_buckets_partial_nr]);
1124 ob->on_partial_list = false;
1125 spin_unlock(&c->freelist_lock);
1126 bch2_open_bucket_put(c, ob);
1127 spin_lock(&c->freelist_lock);
1128 } else {
1129 i++;
1130 }
1131 }
1132 spin_unlock(&c->freelist_lock);
fs/bcachefs/alloc_foreground.c
1043 static bool should_drop_bucket(struct open_bucket *ob, struct bch_fs
*c,
1044 struct bch_dev *ca, bool ec)
1045 {
1046 if (ec) {
1047 return ob->ec != NULL;
1048 } else if (ca) {
1049 bool drop = ob->dev == ca->dev_idx;
1050 struct open_bucket *ob2;
1051 unsigned i;
1052
1053 if (!drop && ob->ec) {
1054 unsigned nr_blocks;
1055
--> 1056 mutex_lock(&ob->ec->lock);
Sleeps. Do you have CONFIG_DEBUG_ATOMIC_SLEEP enabled in your .config?
1057 nr_blocks =
bkey_i_to_stripe(&ob->ec->new_stripe.key)->v.nr_blocks;
1058
1059 for (i = 0; i < nr_blocks; i++) {
1060 if (!ob->ec->blocks[i])
1061 continue;
1062
1063 ob2 = c->open_buckets +
ob->ec->blocks[i];
1064 drop |= ob2->dev == ca->dev_idx;
1065 }
1066 mutex_unlock(&ob->ec->lock);
1067 }
1068
1069 return drop;
1070 } else {
1071 return true;
1072 }
1073 }
regards,
dan carpenter
