On Thu, Aug 07, 2014 at 11:35:50AM +0800, Zheng Liu wrote: > From: Zheng Liu <wenqing.lz@xxxxxxxxxx> > > Currently extent status tree doesn't cache extent hole when a write > looks up in extent tree to make sure whether a block has been allocated > or not. In this case, we don't put extent hole in extent cache because > later this extent might be removed and a new delayed extent might be > added back. But it will cause a defect when we do a lot of writes. > If we don't put extent hole in extent cache, the following writes also > need to access extent tree to look at whether or not a block has been > allocated. It brings a cache miss. This commit fixes this defect. > Meanwhile, if an inode has no any extent, this extent hole also will > be cached. Hi Zheng, I thought the reason why we have the EXT4_GET_BLOCKS_NO_PUT_HOLE flag is because in ext4_da_map_blocks(), if there is a hole, we will be immediately following it up with a call to ext4_es_insert_extent() to fill in the hole with the EXTENT_STATUS_DELAYED flag. The only time we don't is if we run into an ENOSPC error. Am I missing something? - Ted -- 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
