Improving ext4: bigalloc, inline data, and metadata checksums

Posted Dec 12, 2011 18:53 UTC (Mon) by andresfreund (subscriber, #69562)
In reply to: Improving ext4: bigalloc, inline data, and metadata checksums by dlang
Parent article: Improving ext4: bigalloc, inline data, and metadata checksums

Err. Read the code. xfs uses io completion callbacks and only relies on the contents of the journal after the completion returned. (xlog_sync()->xlog_bdstrat()->xfs_buf_iorequest()->_xfs_buf_ioend()).
jbd does something similar but I don't want to look it up unless youre really interested.

It worked a littlebit more like you describe before 2.6.37 but back then it waited if barriers were disabled.

Improving ext4: bigalloc, inline data, and metadata checksums

Posted Dec 13, 2011 13:35 UTC (Tue) by nix (subscriber, #2304) [Link] (1 responses)

Well, this is clear as mud :) guess I'd better do some code reading and figure out wtf the properties of the system actually are...

Improving ext4: bigalloc, inline data, and metadata checksums

Posted Dec 13, 2011 13:38 UTC (Tue) by andresfreund (subscriber, #69562) [Link]

If you want I can give you the approx calltrace for jbd2 as well, I know it took me some time when I looked it up...