A btrfs update at LinuxCon Europe [LWN.net]

A btrfs update at LinuxCon Europe

Posted Nov 10, 2011 12:59 UTC (Thu) by callegar (guest, #16148)
Parent article: A btrfs update at LinuxCon Europe

Btrfs is not the only filesystem without a checker, unfortunately. UDF is in the same condition. Which is equally bad since it leaves linux without an unencumbered , vendor neutral, cross platform, filesystem (and most likely this is the reason why every linux user still sticks with FAT). And which is also sort of funny, since many people do backups on that. I wonder if this btrfs case may result in more attention from distributions at the need to invest in tools so that /all/ filesystems that are supported with R/W can be checked and in case something goes wrong some data recovery can be practiced.

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UDF

Posted Nov 11, 2011 11:25 UTC (Fri) by eru (subscriber, #2753) [Link]

Can UDF really be used as a normal R/W FS on a) Linux, b) Windows? I have only ever seen in on DVD:s, and I suspect OS'es might cheat and not implement UDF features not needed for that task.

UDF

Posted Nov 11, 2011 23:19 UTC (Fri) by cladisch (✭ supporter ✭, #50193) [Link]

> Can UDF really be used as a normal R/W FS on a) Linux, b) Windows?

Yes; it's essentially a 'normal' file system like, e.g., ext2.

> I have only ever seen in on DVD:s, and I suspect OS'es might cheat and not implement UDF features not needed for that task.

The Linux UDF driver defaulted to a 2048 byte sector size which would be wrong for other disk types; this was fixed two years ago. The userspace tool (mkudffs) still has the same bug; you need to remember to specify the sector size explicitly when formatting a HD or a USB stick.
Windows doesn't have this problem.

At that time, there were problems with interchanging data between OSes (IIRC new files created in Linux didn't always show up in Windows); I don't know if this is still the case.

JFFS2 also has no fsck

Posted Nov 13, 2011 22:35 UTC (Sun) by skierpage (guest, #70911) [Link]

("Journalling Flash File System version 2 or JFFS2 is a log-structured file system for use with flash memory devices.")

It worked fine on my One Laptop Per Child laptop for years until it didn't, and there's no utility to repair it; neither Wikipedia nor its FAQ mention this absence. Fortunately (?) userspace has no idea of the carnage going on below it, so I could tar off my files despite all the "jffs2_get_inode_nodes: Eep. No valid nodes for ino #340448" syslog messages.