On Tue, May 14, 2013 at 08:57:54PM +0200, folkert wrote: > > > Ok. But that would only when the filesystem is not mounted. > > > Maybe some on-line functionality for doing so would be nice. I'm not > > > totally aware of the filesystem structures in memory/on disk, but > > > reading meta-data from disk which has changes pending in memory/in the > > > journal would give at worst a verify of old(er) data. I don't think this > > > (checking occasional old data) is a bad thing - scrubbing a > > > raid-device/disk doesn't give you the situation for the whole disk(s) in > > > 1 (!) point at time either. If that would be required, then the user > > > could still unmount the filesystem and do a check. > > > > Well... if you ran filefrag -v on every file on the disk and read all the > > xattrs, you'd scrub nearly all the metadata. The only things you'd miss are > > unallocated parts of the disk, most of which e2fsck also skips. > > Yes but that is, imho, a bit dirty method. > Because I assume the result will be a message in dmesg and the > filesystem being remounted r/o? > I think it would be better if a nice message on the user's terminal and > an exit code. You should see "I/O Error" (or whatever -EIO becomes in the message catalog) on the terminal running filefrag if you hit a checksum error, in addition to a complaint in dmesg and a ro fs. > > > > That's not currently on the development roadmap; I could imagine > > > > someone deciding to design an extension to ext4 that would do this > > > > probably by storing the checksums in the indirect blocks, but no one > > > > is currently working on it. > > > > sha256sum < file > file.sha256 ? :D > > Then you would need to read the whole file. I think it would be better > to have this on e.g. block-level. 4KB so CRC32 suffices? block or bigalloc-cluster level, I suppose. --D > > > (If only there was disk space and brain-time to do something where you could > > *reconstruct* data.) > > ah yes. > These days everything is done by the gpu, maybe it can help with that :) > > > Folkert van Heusden > > -- > www.vanheusden.com/multitail - multitail is tail on steroids. multiple > windows, filtering, coloring, anything you can think of > ---------------------------------------------------------------------- > Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
