On Thu, May 12, 2011 at 09:57:07PM +0800, Wu Fengguang wrote: > sync(2) is performed in two stages: the WB_SYNC_NONE sync and the > WB_SYNC_ALL sync. Tag the first stage with wbc.tagged_sync and do > livelock prevention for it, too. > > Note that writeback_inodes_sb() is called by not only sync(), they are > treated the same because the other callers also need livelock prevention. > > Impact: It changes the order in which pages/inodes are synced to disk. > Now in the WB_SYNC_NONE stage, it won't proceed to write the next inode > until finished with the current inode. What about all the filesystems that implement their own .writepages()/write_cache_pages() functions or have have special code that checks WB_SYNC_ALL in .writepages (e.g. gfs2, ext4, btrfs and perhaps others). Don't they all need to be aware of this tagged_sync field? Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
