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duplicati/Duplicati/Library/Snapshots/UsnJournalService.cs
T

515 lines
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C#

// Copyright (C) 2024, The Duplicati Team
// https://duplicati.com, hello@duplicati.com
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using Duplicati.Library.Interface;
using Duplicati.Library.Common.IO;
using Duplicati.Library.Utility;
namespace Duplicati.Library.Snapshots
{
public class UsnJournalService
{
/// <summary>
/// The log tag to use
/// </summary>
private static readonly string FILTER_LOGTAG = Logging.Log.LogTagFromType(typeof(UsnJournalService));
private readonly ISnapshotService m_snapshot;
private readonly IEnumerable<string> m_sources;
private readonly Dictionary<string, VolumeData> m_volumeDataDict;
private readonly CancellationToken m_token;
/// <summary>
/// Constructor.
/// </summary>
/// <param name="sources">Sources to filter</param>
/// <param name="snapshot"></param>
/// <param name="emitFilter">Emit filter</param>
/// <param name="fileAttributeFilter"></param>
/// <param name="skipFilesLargerThan"></param>
/// <param name="prevJournalData">Journal-data of previous fileset</param>
/// <param name="token"></param>
public UsnJournalService(IEnumerable<string> sources, ISnapshotService snapshot, IFilter emitFilter, FileAttributes fileAttributeFilter,
long skipFilesLargerThan, IEnumerable<USNJournalDataEntry> prevJournalData, CancellationToken token)
{
m_sources = sources;
m_snapshot = snapshot;
m_volumeDataDict = Initialize(emitFilter, fileAttributeFilter, skipFilesLargerThan, prevJournalData);
m_token = token;
}
public IEnumerable<VolumeData> VolumeDataList => m_volumeDataDict.Select(e => e.Value);
/// <summary>
/// Initialize list of modified files / folder for each volume
/// </summary>
/// <param name="emitFilter"></param>
/// <param name="fileAttributeFilter"></param>
/// <param name="skipFilesLargerThan"></param>
/// <param name="prevJournalData"></param>
/// <returns></returns>
private Dictionary<string, VolumeData> Initialize(IFilter emitFilter, FileAttributes fileAttributeFilter, long skipFilesLargerThan,
IEnumerable<USNJournalDataEntry> prevJournalData)
{
if (prevJournalData == null)
throw new UsnJournalSoftFailureException(Strings.USNHelper.PreviousBackupNoInfo);
var result = new Dictionary<string, VolumeData>();
// get hash identifying current source filter / sources configuration
var configHash = Utility.Utility.ByteArrayAsHexString(MD5HashHelper.GetHash(new string[] {
emitFilter == null ? string.Empty : emitFilter.ToString(),
string.Join("; ", m_sources),
fileAttributeFilter.ToString(),
skipFilesLargerThan.ToString()
}));
// create lookup for journal data
var journalDataDict = prevJournalData.ToDictionary(data => data.Volume);
// iterate over volumes
foreach (var sourcesPerVolume in SortByVolume(m_sources))
{
Logging.Log.WriteVerboseMessage(FILTER_LOGTAG, "UsnInitialize", "Reading USN journal for volume: {0}", sourcesPerVolume.Key);
if (m_token.IsCancellationRequested) break;
var volume = sourcesPerVolume.Key;
var volumeSources = sourcesPerVolume.Value;
var volumeData = new VolumeData
{
Volume = volume,
JournalData = null
};
result[volume] = volumeData;
try
{
// prepare journal data entry to store with current fileset
var journal = new USNJournal(volume);
var nextData = new USNJournalDataEntry
{
Volume = volume,
JournalId = journal.JournalId,
NextUsn = journal.NextUsn,
ConfigHash = configHash
};
// add new data to result set
volumeData.JournalData = nextData;
// only use change journal if:
// - journal ID hasn't changed
// - nextUsn isn't zero (we use this as magic value to force a rescan)
// - the configuration (sources or filters) hasn't changed
if (!journalDataDict.TryGetValue(volume, out var prevData))
throw new UsnJournalSoftFailureException(Strings.USNHelper.PreviousBackupNoInfo);
if (prevData.JournalId != nextData.JournalId)
throw new UsnJournalSoftFailureException(Strings.USNHelper.JournalIdChanged);
if (prevData.NextUsn == 0)
throw new UsnJournalSoftFailureException(Strings.USNHelper.NextUsnZero);
if (prevData.ConfigHash != nextData.ConfigHash)
throw new UsnJournalSoftFailureException(Strings.USNHelper.ConfigHashChanged);
var changedFiles = new HashSet<string>(Utility.Utility.ClientFilenameStringComparer);
var changedFolders = new HashSet<string>(Utility.Utility.ClientFilenameStringComparer);
// obtain changed files and folders, per volume
foreach (var source in volumeSources)
{
if (m_token.IsCancellationRequested) break;
foreach (var entry in journal.GetChangedFileSystemEntries(source, prevData.NextUsn))
{
if (m_token.IsCancellationRequested) break;
if (entry.Item2.HasFlag(USNJournal.EntryType.File))
{
changedFiles.Add(entry.Item1);
}
else
{
changedFolders.Add(Util.AppendDirSeparator(entry.Item1));
}
}
}
// At this point we have:
// - a list of folders (changedFolders) that were possibly modified
// - a list of files (changedFiles) that were possibly modified
//
// With this, we need still need to do the following:
//
// 1. Simplify the folder list, such that it only contains the parent-most entries
// (eg. { "C:\A\B\", "C:\A\B\C\", "C:\A\B\D\E\" } => { "C:\A\B\" }
volumeData.Folders = Utility.Utility.SimplifyFolderList(changedFolders).ToList();
// 2. Our list of files may contain entries inside one of the simplified folders (from step 1., above).
// Since that folder is going to be fully scanned, those files can be removed.
// Note: it would be wrong to use the result from step 2. as the folder list! The entries removed
// between 1. and 2. are *excluded* folders, and files below them are to be *excluded*, too.
volumeData.Files =
new HashSet<string>(Utility.Utility.GetFilesNotInFolders(changedFiles, volumeData.Folders));
// Record success for volume
volumeData.IsFullScan = false;
}
catch (Exception e)
{
// full scan is required this time (eg. due to missing journal entries)
volumeData.Exception = e;
volumeData.IsFullScan = true;
volumeData.Folders = new List<string>();
volumeData.Files = new HashSet<string>();
// use original sources
foreach (var path in volumeSources)
{
var isFolder = path.EndsWith(Util.DirectorySeparatorString, StringComparison.Ordinal);
if (isFolder)
{
volumeData.Folders.Add(path);
}
else
{
volumeData.Files.Add(path);
}
}
}
}
return result;
}
/// <summary>
/// Filters sources, returning sub-set having been modified since last
/// change, as specified by <c>journalData</c>.
/// </summary>
/// <param name="filter">Filter callback to exclude filtered items</param>
/// <returns>Filtered sources</returns>
public IEnumerable<string> GetModifiedSources(Utility.Utility.EnumerationFilterDelegate filter)
{
// iterate over volumes
foreach (var volumeData in m_volumeDataDict)
{
// prepare cache for includes (value = true) and excludes (value = false, will be populated
// on-demand)
var cache = new Dictionary<string, bool>();
foreach (var source in m_sources)
{
if (m_token.IsCancellationRequested)
{
break;
}
cache[source] = true;
}
// Check the simplified folders, and their parent folders against the exclusion filter.
// This is needed because the filter may exclude "C:\A\", but this won't match the more
// specific "C:\A\B\" in our list, even though it's meant to be excluded.
// The reason why the filter doesn't exclude it is because during a regular (non-USN) full scan,
// FilterHandler.EnumerateFilesAndFolders() works top-down, and won't even enumerate child
// folders.
// The sources are needed to stop evaluating parent folders above the specified source folders
if (volumeData.Value.Folders != null)
{
foreach (var folder in FilterExcludedFolders(volumeData.Value.Folders, filter, cache).Where(m_snapshot.DirectoryExists))
{
if (m_token.IsCancellationRequested)
{
break;
}
yield return folder;
}
}
// The simplified file list also needs to be checked against the exclusion filter, as it
// may contain entries excluded due to attributes, but also because they are below excluded
// folders, which themselves aren't in the folder list from step 1.
// Note that the simplified file list may contain entries that have been deleted! They need to
// be kept in the list (unless excluded by the filter) in order for the backup handler to record their
// deletion.
if (volumeData.Value.Files != null)
{
foreach (var files in FilterExcludedFiles(volumeData.Value.Files, filter, cache).Where(m_snapshot.FileExists))
{
if (m_token.IsCancellationRequested)
{
break;
}
yield return files;
}
}
}
}
/// <summary>
/// Filter supplied <c>files</c>, removing any files which itself, or one
/// of its parent folders, is excluded by the <c>filter</c>.
/// </summary>
/// <param name="files">Files to filter</param>
/// <param name="filter">Exclusion filter</param>
/// <param name="cache">Cache of included and excluded files / folders</param>
/// <param name="errorCallback"></param>
/// <returns>Filtered files</returns>
private IEnumerable<string> FilterExcludedFiles(IEnumerable<string> files,
Utility.Utility.EnumerationFilterDelegate filter, IDictionary<string, bool> cache, Utility.Utility.ReportAccessError errorCallback = null)
{
var result = new List<string>();
foreach (var file in files)
{
if (m_token.IsCancellationRequested)
{
break;
}
var attr = m_snapshot.FileExists(file) ? m_snapshot.GetAttributes(file) : FileAttributes.Normal;
try
{
if (!filter(file, file, attr))
continue;
if (!IsFolderOrAncestorsExcluded(Utility.Utility.GetParent(file, true), filter, cache))
{
result.Add(file);
}
}
catch (System.Threading.ThreadAbortException)
{
throw;
}
catch (Exception ex)
{
errorCallback?.Invoke(file, file, ex);
filter(file, file, attr | Utility.Utility.ATTRIBUTE_ERROR);
}
}
return result;
}
/// <summary>
/// Filter supplied <c>folders</c>, removing any folder which itself, or one
/// of its ancestors, is excluded by the <c>filter</c>.
/// </summary>
/// <param name="folders">Folder to filter</param>
/// <param name="filter">Exclusion filter</param>
/// <param name="cache">Cache of excluded folders (optional)</param>
/// <param name="errorCallback"></param>
/// <returns>Filtered folders</returns>
private IEnumerable<string> FilterExcludedFolders(IEnumerable<string> folders,
Utility.Utility.EnumerationFilterDelegate filter, IDictionary<string, bool> cache, Utility.Utility.ReportAccessError errorCallback = null)
{
var result = new List<string>();
foreach (var folder in folders)
{
if (m_token.IsCancellationRequested)
{
break;
}
try
{
if (!IsFolderOrAncestorsExcluded(folder, filter, cache))
{
result.Add(folder);
}
}
catch (System.Threading.ThreadAbortException)
{
throw;
}
catch (Exception ex)
{
errorCallback?.Invoke(folder, folder, ex);
filter(folder, folder, FileAttributes.Directory | Utility.Utility.ATTRIBUTE_ERROR);
}
}
return result;
}
/// <summary>
/// Tests if specified folder, or any of its ancestors, is excluded by the filter
/// </summary>
/// <param name="folder">Folder to test</param>
/// <param name="filter">Filter</param>
/// <param name="cache">Cache of excluded folders (optional)</param>
/// <returns>True if excluded, false otherwise</returns>
private bool IsFolderOrAncestorsExcluded(string folder, Utility.Utility.EnumerationFilterDelegate filter, IDictionary<string, bool> cache)
{
List<string> parents = null;
while (folder != null)
{
if (m_token.IsCancellationRequested)
{
break;
}
// first check cache
if (cache.TryGetValue(folder, out var include))
{
if (include)
return false;
break; // hit!
}
// remember folder for cache
if (parents == null)
{
parents = new List<string>(); // create on-demand
}
parents.Add(folder);
var attr = m_snapshot.DirectoryExists(folder) ? m_snapshot.GetAttributes(folder) : FileAttributes.Directory;
if (!filter(folder, folder, attr))
break; // excluded
folder = Utility.Utility.GetParent(folder, true);
}
if (folder != null)
{
// update cache
parents?.ForEach(p => cache[p] = false);
}
return folder != null;
}
/// <summary>
/// Sort sources by root volume
/// </summary>
/// <param name="sources">List of sources</param>
/// <returns>Dictionary of volumes, with list of sources as values</returns>
private static Dictionary<string, List<string>> SortByVolume(IEnumerable<string> sources)
{
var sourcesByVolume = new Dictionary<string, List<string>>();
foreach (var path in sources)
{
// get NTFS volume root
var volumeRoot = USNJournal.GetVolumeRootFromPath(path);
if (!sourcesByVolume.TryGetValue(volumeRoot, out var list))
{
list = new List<string>();
sourcesByVolume.Add(volumeRoot, list);
}
list.Add(path);
}
return sourcesByVolume;
}
/// <summary>
/// Returns true if path was enumerated by journal service
/// </summary>
/// <param name="path"></param>
/// <returns></returns>
public bool IsPathEnumerated(string path)
{
// get NTFS volume root
var volumeRoot = USNJournal.GetVolumeRootFromPath(path);
// get volume data
if (!m_volumeDataDict.TryGetValue(volumeRoot, out var volumeData))
return false;
if (volumeData.IsFullScan)
return true; // do not append from previous set, already scanned
if (volumeData.Files.Contains(path))
return true; // do not append from previous set, already scanned
foreach (var folder in volumeData.Folders)
{
if (m_token.IsCancellationRequested)
{
break;
}
if (path.Equals(folder, Utility.Utility.ClientFilenameStringComparison))
return true; // do not append from previous set, already scanned
if (Utility.Utility.IsPathBelowFolder(path, folder))
return true; // do not append from previous set, already scanned
}
return false; // append from previous set
}
}
/// <summary>
/// Filtered sources
/// </summary>
public class VolumeData
{
/// <summary>
/// Volume
/// </summary>
public string Volume { get; set; }
/// <summary>
/// Set of potentially modified files
/// </summary>
public HashSet<string> Files { get; internal set; }
/// <summary>
/// Set of folders that are potentially modified, or whose children
/// are potentially modified
/// </summary>
public List<string> Folders { get; internal set; }
/// <summary>
/// Journal data to use for next backup
/// </summary>
public USNJournalDataEntry JournalData { get; internal set; }
/// <summary>
/// If true, a full scan for this volume was required
/// </summary>
public bool IsFullScan { get; internal set; }
/// <summary>
/// Optional exception message for volume
/// </summary>
public Exception Exception { get; internal set; }
}
}