On Wed, May 18, 2011 at 11:29:14AM +0800, Li Dongyang wrote: > Thanks for the fix, I thought EOPNOTSUPP could be useful by the caller > that time, and maybe we could do somthing like remove the discard > mount_opt in the fs_info so we can avoid calling it again.
I do not agree that discard should be removed from mount_opt, because one may add TRIM-capable devices later, it's a whole filesystem option, while. A disappeared discard mount option will probably cause panic in administrator's head. However, if a drive does not support TRIM, the btrfs_issue_discard calls can take a shortcut and do not call up to blkdev_issue_discard (though it does return immediatelly), caching the state after first call. But this is matter of the lower level call (blkdev) and should not be propagated beyond to the extent "level" (ie. btrfs_discard_extent). david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
