Hi Ted, I noticed the following item on Ext4 TODO list: * Improve merging of adjacent extents in the extent tree (i.e., both to the left and to the right) ** Investigate better code factorization in all of the places that manipulate the extent tree (ext4_get_blocks, fallocate, direct I/O, uninit-to-init conversion code) I wanted to bring to your attention (and everybody else's), the experimental work that Yongqiang has been doing in his ext4-defrag branch: https://github.com/YANGYongqiang/ext4-snapshots/blob/ext4-defrag/fs/dext4/extents.c#L3547 His work is related to my post on opportunistic de-fragmentation: http://marc.info/?l=linux-ext4&m=128927606801750&w=2 Another related work on his queue, which involves manipulation of extent tree, is the move-on-write implementation for extent mapped files. Anyway, if you have any tips for Yongqiang, regarding better code factorization or other opportunities in which extent merging can take place, please share your insight with us. Also, if there already is a parallel effort on the subject, please let us know, so we can collaborate efforts. Thanks, Amir. -- 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