On Mon, Sep 08, 2014 at 04:11:43PM -0700, Darrick J. Wong wrote: > It turns out that there are some serious problems with the on-disk > format of journal checksum v2. The foremost is that the function to > calculate descriptor tag size returns sizes that are too big. This > causes alignment issues on some architectures and is compounded by the > fact that some parts of jbd2 use the structure size (incorrectly) to > determine the presence of a 64bit journal instead of checking the > feature flags. These errors regrettably lead to the journal > corruption reported by Mr. Reardon. > > Therefore, introduce journal checksum v3, which enlarges the > descriptor block tag format to allow for full 32-bit checksums of > journal blocks, fix the journal tag function to return the correct > sizes, and fix the jbd2 recovery code to use feature flags to > determine 64bitness. > > Add a few function helpers so we don't have to open-code quite so > many pieces. > > Switching to a 16-byte block size was found to increase journal size > overhead by a maximum of 0.1%, to convert a 32-bit journal with no > checksumming to a 32-bit journal with checksum v3 enabled. > > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > Reported-by: TR Reardon <thomas_reardon@xxxxxxxxxxx> Applied, thanks. - Ted -- 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
