2009/11/23 <tytso@xxxxxxx>: > On Mon, Nov 23, 2009 at 11:57:44AM +0000, Duane Griffin wrote: >> Unfortunately you can't just blindly give back the journalled block: >> it may have been escaped. So you need to read in the block from the >> journal, unescape it if required, then give it back. > > Good point; this is going to make supporting a read-only mount that > doesn't replay the journal very difficult to implement for > data=journal mode, since it would mean intercepting the actual block > I/O read functions for data reads, which is outside of fs/ext4 in the > generic fs/ and mm/ functions. Doing it for metadata blocks will be > annoying, but at least it's all inside fs/ext4. Yes, that is the sticking point I got to with my last attempt at this :( I was kinda hoping that someone would have a bright idea that doesn't involve hacking an IO completion callback into get_block_t... > - Ted Cheers, Duane. -- "I never could learn to drink that blood and call it wine" - Bob Dylan -- 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
