On 1/3/14, 11:51 AM, Theodore Ts'o wrote: > On Fri, Jan 03, 2014 at 11:23:54AM -0600, Eric Sandeen wrote: >>> The BLKFLSBUF ioctl does __not__ send a CACHE FLUSH command to the >>> hardware device. It forces all of the dirty buffers in memory to the >>> storage device, and then it invalidates all the buffer cache, but it >>> does not send a CACHE FLUSH command to the hardware. Hence, the >>> hardware is free to write it to its on-disk cache, and not necessarily >>> guarantee that the data is written to stable store. (For an example >>> use case of BLKFLSBUF, we use it in e2fsck to drop the buffer cache >>> for benchmarking purposes.) >> >> Are you sure? for a bdev w/ ext4 on it: >> >> BLKFLSBUF >> fsync_bdev >> sync_filesystem >> sync_fs >> ext4_sync_fs >> blkdev_issue_flush > > This call chain only happens if the block device is mounted. Sure, but I thought that's what they were doing. Maybe I misread. -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
