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Problems with fsarchiver and ntfs-3g 
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Joined: Thu Aug 14, 2014 14:58
Posts: 2
Post Problems with fsarchiver and ntfs-3g
Here and in other forums, it was reported that the backup partition of windows7 with fsarchiver is faulty.
The error can be corrected:

I use Ubuntu 14.04 and fsarchiver/qt4-fsarchiver.
If I backed win7 or win8-partitions I get errormessages.
I download ntfs-3g_ntfsprogs-20142,15.tgz from Tuxera.
I removed in dir.c line 2325 in the function
Code:
static int get_dos_name(ntfs_inode *ni, u64 dnum, ntfschar *dosname)

this code:
Quote:
outsize = -1;

After compilation
Code:
./configure
make
sudo make install


fsarchiver works without problems.
I can backed win7 und win8 partitions without error

The code
Quote:
outsize = -1;

is this a mistake in ntfs-3g?

Regards
Dieter_Ubuntu


Thu Aug 14, 2014 17:11
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NTFS-3G Lead Developer

Joined: Tue Sep 04, 2007 17:22
Posts: 1286
Post Re: Problems with fsarchiver and ntfs-3g
Hi,

Quote:
fsarchiver works without problems.
I can backed win7 und win8 partitions without error

You have blocked the error report, but are you sure you are able to restore the partition ?
Quote:
Code:
outsize = -1;

is this a mistake in ntfs-3g?

Unfortunately, this is intentional. Prior to ntfs-3g 2012.1.15AR.8 getting dos names on files with several names (aka hard links) was allowed, and this has sometimes led to bad backups. So this possibility has been removed to avoid loss of data.

The technical reason is that ntfs-3g relies on fuse, and the way the kernel communicates with the user space is based on inode numbers. So when some part of a file is requested, no name is mentioned, only the inode number. As a consequence, when a dos name is requested, the file system does not know for sure which file name and which path were designated in the request, and the dos name may end up being associated to a wrong (long) name, even in a wrong directory.

I am open to collaboration with archivers developers for defining a proper way to associate a dos name to the correct long name.

Regards

Jean-Pierre


Thu Aug 14, 2014 21:32
Profile

Joined: Mon Sep 15, 2014 01:55
Posts: 1
Post Re: Problems with fsarchiver and ntfs-3g
I use fsarchiver on the SystemRescueCD to perform partition back ups and restores of a Win 7 Professional x64 machine. Before the issue of ntfs-3g getting/setting dos file names came to light I successfully use SystemRescueCD 1.4.0 which comes with fsarchiver 0.6.8 (2010-02-20) and ntfs-3g 2010.1.16 (integrated FUSE 28) to both create and restore Win 7 boot images. No errors were reported when creating or restoring the backup (although they may been happening silently). I've ran on one of these fsarchiver backed up and restored images for over four years with no apparent problems caused by the backup/restore.

Starting with System Rescue CD 1.5.4 which includes fsarchiver 0.6.10 (2010-05-09) and ntfs-3g 2010.3.6 integrated FUSE 28 I started to have a few errors. Ten errors like this:
[errno=22, Invalid argument]: oper_restore.c#255,extractar_restore_attr_windows(): winattr:lsetxattr(/Windows/SysWOW64/config/systemprofile/Documents/My Music,system.ntfs_reparse_data) failed
And five dos name errors like this:
[errno=5, Input/output error]: oper_restore.c#255,extractar_restore_attr_windows(): winattr:lsetxattr(/Users/WilliamGates/AppData/LocalLow/Microsoft/Windows Live/Setup/tmp/0g39sh58/PIMT.cab,system.ntfs_dos_name) failed

Because of these errors I reverted back to using SystemRescueCD 1.4.0 (fsarchiver 0.6.8 (2010-02-20) and ntfs-3g 2010.1.16 (integrated FUSE 28)).

Recently I tried System Rescue CD 4.3.1 which includes fsarchiver 0.6.19 and ntfs-3g 2014.2.15, but it returns over 10,000 of the "system.ntfs_dos_name returned negative attribute size" errors. I assume these last 10,000 errors are because of the change introduced in ntfs-3g 2012.1.15AR.8 to block the dos names of files with multiple hard links.

Or at least I think that change only applies to files with multiple hard links. Jean-Pierre, does the ntfs-3g 2012.1.15AR.8 change only apply to files with dos names AND multiple hard links or does it apply to all files with dos names (regardless of the # of hard links)? Is ntfs-3g 2012.1.15AR.8 newer than ntfs-3g 2012.1.15?


Since my backups and restores with earlier versions of the software seem to work fine, I've once again gone back to using SystemRescueCD 1.4.0 (fsarchiver 0.6.8 (2010-02-20) and ntfs-3g 2010.1.16 (integrated FUSE 28)). While I wouldn't back up a production server in this manner, I have yet to experience any problems with the few WinXP and Win7 desktops I've backed up and restored with fsarchiver 0.6.8 (2010-02-20) and ntfs-3g 2010.1.16.

If I understand correctly the posts about this issue the worst case is that some files may have incorrect short (DOS) names. However even if a dos name is set incorrectly I think most programs have moved on to using long file names by now.

I don't understand the ntfs_reparse_data errors as well. Are these ntfs_reparse_data errors silently happening with older versions of ntfs-3g too? If they are, they also don't seem to be causing me any problems.


Sat Sep 20, 2014 22:56
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NTFS-3G Lead Developer

Joined: Tue Sep 04, 2007 17:22
Posts: 1286
Post Re: Problems with fsarchiver and ntfs-3g
Hi,
Quote:
Or at least I think that change only applies to files with multiple hard links. Jean-Pierre, does the ntfs-3g 2012.1.15AR.8 change only apply to files with dos names AND multiple hard links or does it apply to all files with dos names (regardless of the # of hard links)?

The problem only occurs for files with both a dos name and multiple names (a hard link is just another name, and there is no difference between the initial name and names added later). With old ntfs-3g versions the dos name might be associated to a wrong long name, leading to data loss when the file was deleted.
Quote:
Is ntfs-3g 2012.1.15AR.8 newer than ntfs-3g 2012.1.15?

Yes.
Quote:
I have yet to experience any problems with the few WinXP and Win7 desktops I've backed up and restored with fsarchiver 0.6.8 (2010-02-20) and ntfs-3g 2010.1.16.

WinXP did not use hard links, so there should be no problem. Win7 has begun to use hard links gradually, and Win8 uses a lot of hard links.
DOS names are an obsolescent feature, only useful for running very old applications, but the major issue is that fsarchiver does not restore files which have dos name errors.

For saving/restoring system partitions, ntfsclone is probably a better option. On the contrary fsarchiver is a better option for user files.
Quote:
If I understand correctly the posts about this issue the worst case is that some files may have incorrect short (DOS) names.

The dos names are correct, but they may be associated to a wrong name (of the same file), possibly in a wrong directory.
Quote:
I don't understand the ntfs_reparse_data errors as well. Are these ntfs_reparse_data errors silently happening with older versions of ntfs-3g too? If they are, they also don't seem to be causing me any problems.

I do not know about this issue, and I do not remember of any change. The main problem with reparse data is that they use Windows dependent references (drive letters and guids), so restoring on a different configuration is meaningless. In which situation did you get an error ?

Regards

Jean-Pierre


Sun Sep 21, 2014 10:50
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