On 6/2/11 8:02 PM, Christoph Hellwig wrote: > On Thu, Jun 02, 2011 at 08:54:03PM -0400, Vivek Goyal wrote: >> Just wondering why ext4 and XFS behavior are different and which is a >> more appropriate behavior. ext4 does not seem to be waiting for all >> pending AIO/DIO to finish while XFS does. > > They're both wrong. Ext4 completely misses support in fsync or sync > to catch pending unwrittent extent conversions, and thus fails to obey > the data integrity guarante. I'm not sure about that. ext4_sync_file() does ext4_flush_completed_IO() which does: * When IO is completed, the work to convert unwritten extents to * written is queued on workqueue but may not get immediately * scheduled. When fsync is called, we need to ensure the * conversion is complete before fsync returns. * The inode keeps track of a list of pending/completed IO that * might needs to do the conversion. This function walks through * the list and convert the related unwritten extents for completed IO * to written. Granted, I get easily lost in ext4's codepaths here, which is actually why I suggested Vivek pose these questions to the list ;) -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
