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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2015 Red Hat
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#include <string>
#include <errno.h>
#include "objclass/objclass.h"
#include "cls_cephfs.h"
CLS_VER(1,0)
CLS_NAME(cephfs)
std::ostream &operator<<(std::ostream &out, const ObjCeiling &in)
{
out << "id: " << in.id << " size: " << in.size;
return out;
}
/**
* Set a named xattr to a given value, if and only if the xattr
* is not already set to a greater value.
*
* If the xattr is missing, then it is set to the input integer.
*
* @param xattr_name: name of xattr to compare against and set
* @param input_val: candidate new value, of encode()'able type
* @returns 0 on success (irrespective of whether our new value
* was used) else an error code
*/
template <typename A>
static int set_if_greater(cls_method_context_t hctx,
const std::string &xattr_name, const A input_val)
{
bufferlist existing_val_bl;
bool set_val = false;
int r = cls_cxx_getxattr(hctx, xattr_name.c_str(), &existing_val_bl);
if (r == -ENOENT || existing_val_bl.length() == 0) {
set_val = true;
} else if (r >= 0) {
auto existing_p = existing_val_bl.cbegin();
try {
A existing_val;
decode(existing_val, existing_p);
if (!existing_p.end()) {
// Trailing junk? Consider it invalid and overwrite
set_val = true;
} else {
// Valid existing value, do comparison
set_val = input_val > existing_val;
}
} catch (const buffer::error &err) {
// Corrupt or empty existing value, overwrite it
set_val = true;
}
} else {
return r;
}
// Conditionally set the new xattr
if (set_val) {
bufferlist set_bl;
encode(input_val, set_bl);
return cls_cxx_setxattr(hctx, xattr_name.c_str(), &set_bl);
} else {
return 0;
}
}
static int accumulate_inode_metadata(cls_method_context_t hctx,
bufferlist *in, bufferlist *out)
{
ceph_assert(in != NULL);
ceph_assert(out != NULL);
int r = 0;
// Decode `in`
auto q = in->cbegin();
AccumulateArgs args;
try {
args.decode(q);
} catch (const buffer::error &err) {
return -EINVAL;
}
ObjCeiling ceiling(args.obj_index, args.obj_size);
r = set_if_greater(hctx, args.obj_xattr_name, ceiling);
if (r < 0) {
return r;
}
r = set_if_greater(hctx, args.mtime_xattr_name, args.mtime);
if (r < 0) {
return r;
}
r = set_if_greater(hctx, args.obj_size_xattr_name, args.obj_size);
if (r < 0) {
return r;
}
return 0;
}
// I want to select objects that have a name ending 00000000
// and an xattr (scrub_tag) not equal to a specific value.
// This is so special case that we can't really pretend it's
// generic, so just fess up and call this the cephfs filter.
class PGLSCephFSFilter : public PGLSFilter {
protected:
std::string scrub_tag;
public:
int init(bufferlist::const_iterator& params) override {
try {
InodeTagFilterArgs args;
args.decode(params);
scrub_tag = args.scrub_tag;
} catch (buffer::error &e) {
return -EINVAL;
}
if (scrub_tag.empty()) {
xattr = "";
} else {
xattr = "_scrub_tag";
}
return 0;
}
~PGLSCephFSFilter() override {}
bool reject_empty_xattr() override { return false; }
bool filter(const hobject_t &obj, bufferlist& xattr_data,
bufferlist& outdata) override;
};
bool PGLSCephFSFilter::filter(const hobject_t &obj,
bufferlist& xattr_data, bufferlist& outdata)
{
const std::string need_ending = ".00000000";
const std::string &obj_name = obj.oid.name;
if (obj_name.length() < need_ending.length()) {
return false;
}
const bool match = obj_name.compare (obj_name.length() - need_ending.length(), need_ending.length(), need_ending) == 0;
if (!match) {
return false;
}
if (!scrub_tag.empty() && xattr_data.length() > 0) {
std::string tag_ondisk;
auto q = xattr_data.cbegin();
try {
decode(tag_ondisk, q);
if (tag_ondisk == scrub_tag)
return false;
} catch (const buffer::error &err) {
}
}
return true;
}
PGLSFilter *inode_tag_filter()
{
return new PGLSCephFSFilter();
}
/**
* initialize class
*
* We do two things here: we register the new class, and then register
* all of the class's methods.
*/
CLS_INIT(cephfs)
{
// this log message, at level 0, will always appear in the ceph-osd
// log file.
CLS_LOG(0, "loading cephfs");
cls_handle_t h_class;
cls_method_handle_t h_accumulate_inode_metadata;
cls_register("cephfs", &h_class);
cls_register_cxx_method(h_class, "accumulate_inode_metadata",
CLS_METHOD_WR | CLS_METHOD_RD,
accumulate_inode_metadata, &h_accumulate_inode_metadata);
// A PGLS filter
cls_register_cxx_filter(h_class, "inode_tag", inode_tag_filter);
}
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