"btrfs fsck.never rulez"
Az megvan - a listán írta valaki, majd megkeresem -, hogy nem is biztos, hogy lesz (egyelőre) olyan fsck a btrfs-hez, ami probléma esetén rendbe teszi, hanem helyette egy olyan utility lesz, ami menti az összeborult fs-ről ami menthető?
Szerk:
Getting a repair tool right is a hard problem; without a lot of care, a well-intentioned attempt to repair a filesystem can easily make it worse. Data that may have been recoverable before the repair attempt may no longer be so afterward. Even if a proper btrfsck were available today, it would probably be some years before it reflected enough experience to inspire confidence in users who are concerned about their data.
So it seems that something else is required. That "something else" turns out to be a data recovery tool written by Josef Bacik. This tool has a simple (to explain) job: dig through a corrupted filesystem in read-only mode and extract as much of the data as possible. Since it makes no changes, it cannot make things worse; it seems like a worthwhile tool to have around even if a full repair tool existed.
That tool, along with all the requisite filesystem support, is expected to be available in the 3.2 kernel time frame. Meanwhile, there is a new btrfs-progs repository that will include the recovery tool in the near future. All told, it may not be quite the btrfsck that some users were hoping for, but it should be enough to make those users feel a bit more confident about entrusting their data to a new filesystem.
Forrás: https://lwn.net/Articles/465160/
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trey @ gépház