Re: [rdiff-backup-users] Problems with backup on encfs

[Jakob Unterwurzacher]

Am 30/04/10 12:46, schrieb address@hidden:
> Hi
>
> using rdiff-backup for years now, I currently testing doing backups stored on 
> encfs to support offsite storage. Unfortunatly this results in some unexpected 
> warnings and errors and I have no idea where are they coming from.
>
> The test scenario is easily described:
> I just do a backup on a localy attached storage, into a encfs mounted directory.
> $ encfs /mnt/backup/.cryptdir /mnt/backup/backup
> $ rdiff-backup -v4 --no-hard-links / /mnt/backup/backup/x31
>
> This shows the following warnings, thousands of them, but the numbers are only 
> partly incrementing by one:
>
>
> Warning: listattr('/mnt/backup/backup/x/bin/rdiff-backup.tmp.8'): [Errno 2] No 
> such file or directory
> Warning: listattr('/mnt/backup/backup/x/bin/rdiff-backup.tmp.10'): [Errno 2] No 
> such file or directory
> Warning: listattr('/mnt/backup/backup/x/bin/rdiff-backup.tmp.13'): [Errno 2] No 
> such file or directory
> Warning: listattr('/mnt/backup/backup/x/bin/rdiff-backup.tmp.14'): [Errno 2] No 
> such file or directory
>
>
> Our good old friend strace shows tells us this:
>
>
> lstat64("/mnt/backup/backup/x/bin/rdiff-backup.tmp.10", 0xbfc85a7c) = -1 ENOENT 
> (No such file or directory)
> symlink("gawk-3.1.6", "/mnt/backup/backup/x/bin/rdiff-backup.tmp.10") = 0
> lstat64("/mnt/backup/backup/x/bin/rdiff-backup.tmp.10", {st_mode=S_IFLNK|0777, 
> st_size=10, ...}) = 0
> readlink("/mnt/backup/backup/x/bin/rdiff-backup.tmp.10", "gawk-3.1.6"..., 1023) 
> = 10
> llistxattr("/mnt/backup/backup/x/bin/rdiff-backup.tmp.10", (nil), 0) = -1 
> ENOENT (No such file or directory)
> write(4, "Warning: listattr('/mnt/backup/ba"..., 105) = 105
> lchown32("/mnt/backup/backup/x/bin/rdiff-backup.tmp.10", 0, 0) = 0
> rename("/mnt/backup/backup/x/bin/rdiff-backup.tmp.10", 
> "/mnt/backup/backup/x/bin/awk") = 0

This seems to be a bug in encfs. llistxattr and lgetxattr always returns 
ENOENT for symlinks on encfs. Debian has a bug report for this: 
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=516473 but encfs itself 
has not?: http://code.google.com/p/encfs/issues/list

I can reproduce it with ls -l and getfattr -h with "symlink" on encfs:

$ ls -l symlink
ls: symlink: No such file or directory
lrwxrwxrwx 1 jakob jakob 1 May  4 12:51 symlink -> /

strace:
lgetxattr("symlink", "security.selinux", 0x9e87268, 255) = -1 ENOENT (No 
such file or directory)

$ getfattr -h symlink
getfattr: symlink: No such file or directory

strace:
llistxattr("symlink", (nil), 0)         = -1 ENOENT (No such file or 
directory)


Jakob