On 03/26/2010 12:16 PM, Ric Wheeler wrote: > On 03/26/2010 12:37 PM, Dmitry Monakhov wrote: >> Surbhi Palande<surbhi.palande@xxxxxxxxxxxxx> writes: >> >> >>> Ensure that in the no journal mode the write cache is flushed to the disk by >>> calling a blkdev_issue_flush() which issues a WRITE_BARRIER if necessary. >>> >> As soon as i understand, nojournal mode is assumed to be used for >> fail-free block devices(raid + UPS). So we don't have to worry about >> blkdev's wcache vs persistent storage correctness. No, I don't think so - even with "fail-free" storage, a system crash still results in an inconsistent filesystem; with nojournalling you've made the decision to either fsck or re-mkfs after that event. > I don't think that is a safe assumption. If users want that behavior, > they can mount with fs without barriers... yes, I agree with Ric - even if you don't have journalling, the proper sequence of sync calls should still result in data permanently on disk by default. (though I think using mount -o nobarrier for this purpose, in absence of journalling, overloads the option a little...) -Eric -- 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
