/// <summary>
/// Just reads the bytes off the disk, reading gang blocks as needed.
/// </summary>
/// <param name="blkptr"></param>
/// <param name="dva"></param>
/// <returns>A buffer allocated from <see cref="Program.RentBytes"/>.</returns>
private ArraySegment <byte> ReadPhyical(blkptr_t blkptr, dva_t dva)
{
Vdev dev = mVdevs[dva.VDev];
int hddReadSize = dva.IsGang ? zio_gbh_phys_t.SPA_GANGBLOCKSIZE : blkptr.PhysicalSizeBytes;
var hddBytes = Program.RentBytes(hddReadSize);
dev.ReadBytes(hddBytes, dva.Offset << SPA_MINBLOCKSHIFT);
if (!dva.IsGang)
{
return(hddBytes);
}
var gangHeader = Program.ToStruct <zio_gbh_phys_t>(hddBytes);
bool isChecksumValid = IsEmbeddedChecksumValid(hddBytes, CalculateGangChecksumVerifier(ref blkptr));
Program.ReturnBytes(hddBytes);
hddBytes = default(ArraySegment <byte>);
if (!isChecksumValid)
throw new Exception("Could not find a correct copy of the requested data."); }
private void Load()
{
if (mHdds.Count == 0)
{
throw new Exception("Did not find any hard drives.");
}
//make sure we support reading the pool
foreach (var hdd in mHdds)
{
CheckVersion(hdd.Config);
}
//ensure all HDDs are part of the same pool
var poolGuid = mHdds.Select(h => h.Config.Get <ulong>("pool_guid")).Distinct().ToArray();
if (poolGuid.Length != 1)
{
throw new Exception("Hard drives are part of different pools: " + string.Join(", ", poolGuid.Select(p => p.ToString())));
}
//ensure all HDDs agree on the transaction group id
var txg = mHdds.Select(hdd => hdd.Uberblock.Txg).Distinct().ToArray();
if (txg.Length != 1)
{
throw new Exception("Uberblocks do not all have the same transaction group id: " + string.Join(", ", txg.Select(p => p.ToString())));
}
var ub = mHdds[0].Uberblock;
if (ub.Txg == 0)
{
throw new Exception("Root block pointer's transaction group is zero!");
}
var vdevs = Vdev.CreateVdevTree(mHdds);
mZio = new Zio(vdevs);
mMos = new ObjectSet(mZio, mZio.Get <objset_phys_t>(ub.rootbp));
if (mMos.Type != dmu_objset_type_t.DMU_OST_META)
{
throw new Exception("Given block pointer did not point to the MOS.");
}
mZio.InitMetaSlabs(mMos);
//the second time we will make sure that space maps contain themselves
mZio.InitMetaSlabs(mMos);
var objectDirectory = mMos.ReadEntry(1);
//The MOS's directory sometimes has things that don't like like directory entries.
//For example, the "scan" entry has scrub status stuffed into as an array of longs.
mObjDir = Zap.GetDirectoryEntries(objectDirectory, true);
if (mObjDir.ContainsKey(DDT_STATISTICS))
{
var ddtStats = Zap.Parse(mMos.ReadEntry(mObjDir[DDT_STATISTICS]));
//TODO: maybe do something interesting with the stats
}
{
var configDn = mMos.ReadEntry(mObjDir[CONFIG]);
var configBytes = Program.RentBytes(checked ((int)configDn.AvailableDataSize));
configDn.Read(configBytes, 0);
mConfig = new NvList(configBytes);
Program.ReturnBytes(configBytes);
}
CheckVersion(mConfig);
CheckFeatures();
}
