Hello, >From what I can tell, most of the filesystems that know how to issue commands to flush the write cache also have some mechanism for the user to override whether or not the filesystem actually issues those flushes. Unfortunately, the term "barrier" is obsolete having been changed into flushes in 2.6.36, and many of the filesystems implement the mount options with slightly different syntaxes (barrier=[0|1|none|flush], nobarrier, etc). This patchset adds to the block layer a sysfs knob that an administrator can use to disable flushes, and removes the mount options from the filesystem code. As a starting point, I'm removing the mount options and flush toggle from jbd2/ext4. Anyway, I'm looking for some feedback about refactoring the barrier/flush control knob into the block layer. It sounds like we want a knob that picks the safest option (issue flushes when supported) unless the administrator decides that it is appropriate to do otherwise. I suspect that there are good arguments for not having a knob at all, and good arguments for a safe knob. However, since I don't see the barrier options being removed en masse, I'm assuming that we still want a knob somewhere. Do we need the ignore_fua knob too? Is this the proper way to deprecate mount options out of filesystems? --D -- 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
