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Workaround for Linux bug: return post_op_attr for NFS-RDMA READ3

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Linux NFS RDMA transport has a stupid bug - when the reply doesn't contain
post_op_attr, the data gets offsetted by 84 bytes (size of attributes) and
first 84 bytes are filled with probably random data.
This commit is contained in:
Vitaliy Filippov
2024-12-11 21:09:36 +03:00
parent ae3ca7451f
commit b856524e0c
13 changed files with 112 additions and 31 deletions
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src/nfs/nfs_kv_read.cpp
+41
View File
@@ -37,6 +37,7 @@ static void nfs_kv_continue_read(nfs_kv_read_state *st, int state)
else if (state == 1) goto resume_1;
else if (state == 2) goto resume_2;
else if (state == 3) goto resume_3;
else if (state == 4) goto resume_4;
else
{
fprintf(stderr, "BUG: invalid state in nfs_kv_continue_read()");
@@ -141,6 +142,35 @@ resume_2:
return;
}
}
else if (st->self->rdma_conn)
{
// Take ientry from read_hack_cache for RDMA connections
{
auto rh_it = st->self->parent->kvfs->read_hack_cache.find(st->ino);
if (rh_it != st->self->parent->kvfs->read_hack_cache.end())
{
st->ientry = rh_it->second;
}
}
if (st->ientry.is_null())
{
kv_read_inode(st->self->parent, st->ino, [st](int res, const std::string & value, json11::Json attrs)
{
st->res = res;
st->ientry = attrs;
nfs_kv_continue_read(st, 4);
}, st->allow_cache);
return;
resume_4:
if (st->res < 0 || kv_map_type(st->ientry["type"].string_value()) != NF3REG)
{
auto cb = std::move(st->cb);
cb(st->res < 0 ? st->res : -EINVAL);
return;
}
st->self->parent->kvfs->read_hack_cache[st->ino] = st->ientry;
}
}
st->aligned_offset = align_down(st->offset);
st->aligned_size = align_up(st->offset+st->size) - st->aligned_offset;
assert(!st->aligned_buf);
@@ -198,6 +228,17 @@ int kv_nfs3_read_proc(void *opaque, rpc_op_t *rop)
reply->resok.data.size = st->size;
reply->resok.count = st->size;
reply->resok.eof = st->eof;
if (st->self->rdma_conn)
{
// FIXME Linux NFS RDMA transport has a bug - when the reply
// doesn't contain post_op_attr, the data gets offsetted by
// 84 bytes (size of attributes)...
// So we have to fill it with RDMA. :-(
reply->resok.file_attributes = (post_op_attr){
.attributes_follow = 1,
.attributes = get_kv_attributes(st->self->parent, st->ino, st->ientry),
};
}
}
rpc_queue_reply(st->rop);
delete st;