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https://github.com/facebook/sapling.git
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4ca1838e1c
Summary: If we run out of NFS buffer space while trying to add the final directory entry in TreeInode::readdirImpl we would incorrectly return true, indicating that we've returned the entire listing. This means that on NFS we would incorrectly send an EOF to the client, which would then not send a subsequent, offset readdir request. Because of this, for certain NFS-mounted Eden directory contents, calling `ls` would result in a single file being missing from the listing. Reviewed By: chadaustin Differential Revision: D39911610 fbshipit-source-id: 96a8fc7958a8e800ff7f2489c968f2dde23a86da
90 lines
2.6 KiB
C++
90 lines
2.6 KiB
C++
/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This software may be used and distributed according to the terms of the
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* GNU General Public License version 2.
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*/
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#ifndef _WIN32
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#include "eden/fs/nfs/DirList.h"
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#include <variant>
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#include "eden/fs/nfs/NfsdRpc.h"
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namespace facebook::eden {
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namespace {
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/**
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* NFS is weird, it specifies the maximum amount of entries to be returned by
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* passing the total size of the READDIR3resok structure, therefore we need to
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* account for all the overhead.
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*/
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uint32_t computeInitialRemaining(uint32_t count) {
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if (kNfsDirListInitialOverhead > count) {
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throw std::length_error(
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"NFS READDIR overhead is bigger than the passed in size");
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}
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return count - kNfsDirListInitialOverhead;
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}
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std::variant<XdrList<entry3>, XdrList<entryplus3>> computeListType(
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nfsv3Procs listType) {
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switch (listType) {
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case nfsv3Procs::readdirplus:
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return std::variant<XdrList<entry3>, XdrList<entryplus3>>(
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std::in_place_type<XdrList<entryplus3>>);
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case nfsv3Procs::readdir:
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default:
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return std::variant<XdrList<entry3>, XdrList<entryplus3>>(
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std::in_place_type<XdrList<entry3>>);
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}
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}
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} // namespace
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NfsDirList::NfsDirList(uint32_t count, nfsv3Procs listType)
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: remaining_(computeInitialRemaining(count)),
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list_(computeListType(listType)) {}
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bool NfsDirList::add(
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folly::StringPiece name,
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InodeNumber ino,
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uint64_t offset) {
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auto fn = [name, ino, offset](auto&& list, uint32_t& remainingSize) {
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size_t neededSize;
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using ListType = std::decay_t<decltype(list->list)>;
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using EntryT = typename ListType::value_type;
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// For entryplus3s, we initially add an empty post_op_attr. This is
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// because we don't have access to stat data in this layer. In a
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// separate layer, we will fill in the post_op_attr with the
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// appropriate stat data. For entry3s, we don't need this extra data.
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EntryT entry = EntryT{ino, name.str(), offset};
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// The serialized size includes a boolean indicating that this is not
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// the end of the list.
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neededSize = XdrTrait<EntryT>::serializedSize(entry) +
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XdrTrait<bool>::serializedSize(true);
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if (neededSize > remainingSize) {
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return false;
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}
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remainingSize -= neededSize;
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list->list.push_back(std::move(entry));
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return true;
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};
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if (XdrList<entryplus3>* list = std::get_if<XdrList<entryplus3>>(&list_)) {
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return fn(list, remaining_);
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} else {
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XdrList<entry3>* entry3List = &std::get<XdrList<entry3>>(list_);
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return fn(entry3List, remaining_);
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}
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}
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} // namespace facebook::eden
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#endif
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