I seem to have observed a file on a (writable) snapshot changing
although there were no writes occuring on the snapshot itself. This is
not supposed to happen, right?
Sequence of events:
1. A (writable) snapshot @home-2014-04-16 is taken on a @home subvolume
mounted at /home.
2. The current subvolume (@home) is used (via /home) for continued write
access, no writes are supposed to occur on the snapshot.
3. The snapshot @home-2014-04-16 is backed up (using rdiff-backup) to a
different disk.
4. As the backup is compared to the snapshot @home-2014-04-16, one file
differs.
Further analysis:
The file in @home-2014-04-16 changed its contents (but not mtime or
other metadata) after being backup up from that snapshot. 5 bytes differ.
The previous snapshot @home-2014-04-10 contains the file in its original
form, which is identical to the backup just taken from @home-2014-04-16.
The file change appears identically
- on the last snapshot @home-2014-04-16 and
- on the current subvolume used for writing (@home).
btrfs scrub reports 0 errors.
At the time the snapshot @home-2014-04-16 was taken, the file (an Excel
file) was probably accessed through Samba, which supposedly uses kernel
oplocks (if that makes a difference).
Versions:
- Kernel 3.11.0-19-generic (Ubuntu 13.10)
- btrfs-tools 0.19+20130705-1
- Samba 3.6.18
Any ideas?
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
