Today I found out a single critical file was needed from one of the JFS2 filesystems I was working with the other day. I was able to recover the file and things are working again.

Following a fiber-channel card failure I was asked to help recover some corrupt JFS2 filesystems. They couldn't be fsck-ed but I was able to run fsdb to modify the filesystem meta-data. First I tried replacing their superblock structures which didn't help.

Next I used fsdb to edit the s_state structure in the primary superblock to set its flag from FM_DIRTY 0x00000002 to FM_CLEAN 0x00000000. IBM makes the headers for their filesystems public. The filesystems still would only toggle back to FM_DIRTY when fsck-ed, but I was able to mount them and was unable to see any bad-looking data.

I'm guessing they are not 100% valid, but the vast amount of data appears to be good.

I was able to start Tivoli Storage Manager on these volumes, recall the files I needed, rename them and insert them into the TSM controlled volumes on the primary system where they were recalled by the medical system they were needed for.