>> Hi there, >> >> Sorry for so late voice. >> >> ext4_ext_remove_space() are supposed to be used by truncate, so it >> remove blocks from EOF to start as indicated by while-loop. Now it >> has an end, so I think we'd better limit the while loop from the end >> to the start, but not from EOF to the start. >> >> we can achieve this by assigning path right before while-loop. > > Hi there, > > Well, I tried setting the path using find_extent, but it doesnt look like it > quite worked out. Could you expand a little more on this? It is not > immediately clear to me how we can do this by setting path. It looks like > path is an array of paths that keep track of where we are in the tree. The > current sequence of paths represent the current location, but I dont know > how we could set up a particular sequence of paths with out walking into the > tree to know what it is. I think the while loop just detects when the > search has come back around to top of the tree. If I understand the code > correctly, we would need a sequence of the paths starting at the deepest > path that can still descend to all the extents in the hole, and the sequence > would need to end at the path that points to the extent that contains the > end of the hole. Thus limiting the search to only that subtree that spans > the hole. At least that is my interpretation of the code. It that correct, > or maybe there is something I missed? Correct. > > If that is how it works, maybe what we could do instead check > (path[i].p_idx->ei_block < end) when deciding weather or not to descend? I > think that would get rid of needlessly walking space that is beyond the end > of the hole. And then when we return from the ext4_ext_rm_leaf, we can > check to see if the leaf contains extents appearing before the hole, and > then quit out if it does. Does that sound correct? Thx! Yes, it's applicable and easier. find_extent doe not work, because path.p_block is used to another thing, it is different from find_extent. Setting path just can control end, start can not be controlled this way. Yongqiang. > > Allison Henderson > >> >>> /* root level has p_bh == NULL, brelse() eats this >>> */ >>> brelse(path[i].p_bh); >>> path[i].p_bh = NULL; >>> @@ -3443,7 +3565,7 @@ void ext4_ext_truncate(struct inode *inode) >>> >>> last_block = (inode->i_size + sb->s_blocksize - 1) >>> >> EXT4_BLOCK_SIZE_BITS(sb); >>> - err = ext4_ext_remove_space(inode, last_block); >>> + err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCK); >>> >>> /* In a multi-transaction truncate, we only make the final >>> * transaction synchronous. >>> -- >>> 1.7.1 >>> >>> -- >>> 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 >>> >> >> >> > > -- Best Wishes Yongqiang Yang -- 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
