Bearcat Şándor posted on Sat, 11 Jun 2016 13:54:44 -0600 as excerpted: > I'm about to try a btrfs restore to see what it can do for me. Any > pointers or help here? I don't want to fsck things up further.
FWIW, btrfs restore doesn't write anything at all to the filesystem it's restoring from -- it's read-only in that regard -- so you really don't have to worry about it screwing up a filesystem further. But by the same token, btrfs restore may not do what you think it does. It doesn't try to fix the filesystem. Rather, it's a way to try to salvage anything you can off a filesystem that won't mount, or, as it would be used here, that will mount but where files aren't showing up properly so you can't just copy them elsewhere using normal means. It writes the files it can salvage to some other filesystem, which of course means that whatever filesystem you're writing the files to must have enough room for the files to be written. Also note the various restore options. In particular, the restore metadata option must be used if you want to restore the same ownership, permissions and timestamp information. Otherwise, restore simply writes the files as the user you're running it as (root), using the current umask. Similarly, if you want to restore symlinks and extended attributes, there's options for that, otherwise they aren't restored. And you won't necessarily be wanting to restore snapshots, as you should have backups if needed for the history, and are likely most worried about the current version of the files, so snapshots aren't restored unless you use the appropriate option. Given that the filesystem is still mounted and most files are apparently still readable normally, you may want to copy off what you can that way, and only restore specific files using btrfs restore. Or you may not have room on the destination filesystem to restore everything, and will need to pick only the most important stuff to restore. That's where the pattern-match option comes in. What I did here when I used restore (I had backups of course but they weren't current) was use the metadata and symlinks restore options, and simply restored everything. Note that if a particular directory has a lot of files, restore will begin to think that it's looping to much and that it's stuck. It'll prompt you to continue, and may prompt a *LOT*. Here I have multiple independent small filesystems, so it wasn't a big deal, but you may need to experiment with automating the "yes" if your filesystem is huge (piping the output of the yes command to stdin, for instance, or similar sysadmin prompt automation tricks). A number of folks have mentioned that and requested a way to say "yes, really all, don't ask again", an option that btrfs restore unfortunately doesn't have yet. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
