XFS B+Tree bugfix #169
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XFS B+Tree bugfix #169
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added 2 commits
September 12, 2019 16:41
In XFS source code, bb_leftsib and bb_rightsib (declared in xfs_format.h) are both of type __be32, which is an unsigned int32 (and not 64). While I was there, I added Inode.ToString() to help me differentiate beween inodes: In Linux, inodes are identified by a unique ID. Branch: [xfs-btree-bugfix]
BTreeExtentHeader.LeftSibling's size is 8 bytes. Therefore, RightSibling's offset should be +8, which is 16 (0x10) and not 12 (0xc). Branch: [xfs-btree-bugfix]
Contributor
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@AssafTzurEl Any chance you could add a small unit test which would cover this case? |
Author
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@qmfrederik I hope so... turns out the file "huge\1" in xfs.zip is a b+Tree. Is there a way to retrieve its inode object? If I can do that, I'll be able to assert its inode.LeftSibling and .RightSibling. |
Contributor
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@AssafTzurEl Create a virtual machine, with the vhdx attached to it - mount the filesystem and take a look with xfs_db |
Author
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@zivillian As I wrote, I found an existing VHDX with a candidate file. What I need is a way to retrieve the files's inode programatically, something like GetInode(string fileName) - from there I'll be able to assert the inode's sibling properties. Since I'm not a DiscUtils expert, I asked for help on how to retrieve the inode in code. |
Contributor
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I'm sorry, I totally misunderstood your reply. I came up with the following change, to get the inode. The idea is to make Library/DiscUtils.Core/Vfs/VfsFileSystemFacade.cs | 2 +-
Tests/LibraryTests/Xfs/SampleDataTests.cs | 31 +++++++++++++++++++++++
2 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/Library/DiscUtils.Core/Vfs/VfsFileSystemFacade.cs b/Library/DiscUtils.Core/Vfs/VfsFileSystemFacade.cs
index 97887f80..643989c5 100644
--- a/Library/DiscUtils.Core/Vfs/VfsFileSystemFacade.cs
+++ b/Library/DiscUtils.Core/Vfs/VfsFileSystemFacade.cs
@@ -543,7 +543,7 @@ namespace DiscUtils.Vfs
/// <typeparam name="TDirectory">The concrete type representing directories.</typeparam>
/// <typeparam name="TContext">The concrete type holding global state.</typeparam>
/// <returns>The actual file system instance.</returns>
- protected VfsFileSystem<TDirEntry, TFile, TDirectory, TContext> GetRealFileSystem
+ protected internal VfsFileSystem<TDirEntry, TFile, TDirectory, TContext> GetRealFileSystem
<TDirEntry, TFile, TDirectory, TContext>()
where TDirEntry : VfsDirEntry
where TFile : IVfsFile
diff --git a/Tests/LibraryTests/Xfs/SampleDataTests.cs b/Tests/LibraryTests/Xfs/SampleDataTests.cs
index 68d2e946..740827b6 100644
--- a/Tests/LibraryTests/Xfs/SampleDataTests.cs
+++ b/Tests/LibraryTests/Xfs/SampleDataTests.cs
@@ -79,6 +79,37 @@ namespace LibraryTests.Xfs
}
}
+ [Fact]
+ public void GetInode()
+ {
+ SetupHelper.SetupComplete();
+ using (FileStream fs = File.OpenRead(Path.Combine("..", "..", "..", "Xfs", "Data", "xfs.zip")))
+ using (Stream vhdx = ZipUtilities.ReadFileFromZip(fs))
+ using (var diskImage = new DiskImageFile(vhdx, Ownership.Dispose))
+ using (var disk = new Disk(new List<DiskImageFile> { diskImage }, Ownership.Dispose))
+ {
+ var manager = new VolumeManager(disk);
+ var logicalVolumes = manager.GetLogicalVolumes();
+ Assert.Single(logicalVolumes);
+
+ var volume = logicalVolumes[0];
+ var filesystems = FileSystemManager.DetectFileSystems(volume);
+ Assert.Single(filesystems);
+
+ var filesystem = filesystems[0];
+ Assert.Equal("xfs", filesystem.Name);
+
+ using (var xfs = filesystem.Open(volume))
+ {
+ var xfsfs = Assert.IsType<XfsFileSystem>(xfs);
+ var vfs = xfsfs.GetRealFileSystem<DirEntry, DiscUtils.Xfs.File, DiscUtils.Xfs.Directory, Context>();
+ var xfsvfs = Assert.IsType<VfsXfsFileSystem>(vfs);
+ var dirEntry = xfsvfs.GetDirectoryEntry("huge\\1");
+ dirEntry.Inode; //<- that's the inode you asked for with RelativeInodeNumber = 202
+ }
+ }
+ }
+
private void ValidateContent(DiscFileSystem xfs)
{
Assert.True(xfs.DirectoryExists(""));
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BTreeExtentHeader.LeftSibling's size is 8 bytes. Therefore, RightSibling's offset should be +8, which is 16 (0x10) and not 12 (0xc).
While I was there, I added Inode.ToString() to help me differentiate beween inodes: In Linux, inodes are identified by a unique ID.