Hi Ted, Andreas and list, This is the v2 attempt to add inline data support to ext4 inode. Formore information about the background, please refer to the thread http://marc.info/?l=linux-ext4&m=131715205428067&w=2 In V1 I uses all the space between i_extra_isize and inode_size if inode_size = 256. For inode_size > 256, half of that space is used so as to leave some space for other xattrs. Andreas suggested that it would make xattr set/get less efficient since it takes too much space for a small inode and xttr would be evicted to the external block. So this V2 now uses the extent space for an inode(60 bytes) at first and then it will try to extend inline data by using the xattr space. So if there are no other xattr, now we can have up to 132 bytes to store the inline data for a inode_size=256. And also as Amir suggested, I have moved all the corresponding codes to fs/ext4/inline.c so that we don't pollute inode.c too much. Some simple tests shows that with a linux-3.0 vanilla source, the new dir can save more than 1% disk space. For my "/usr", it can save more than 3% spaces. I guess for volume with future bigalloc support, it should save more space for us for small dir. There are still something to do in my list: 1. yes, e2fsprogs is very important and we are working on it. 2. evicting inline data in xattr set if the xattr can be inserted into inode as suggested by Andreas. any suggestions are welcomed. git diff --stat master.. fs/ext4/Makefile | 2 +- fs/ext4/dir.c | 36 +- fs/ext4/ext4.h | 72 +++- fs/ext4/extents.c | 9 +- fs/ext4/ialloc.c | 4 + fs/ext4/inline.c | 1426 +++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/ext4/inode.c | 209 ++++++-- fs/ext4/namei.c | 348 +++++++++---- fs/ext4/xattr.c | 39 +-- fs/ext4/xattr.h | 256 ++++++++++ 10 files changed, 2185 insertions(+), 216 deletions(-) Thanks Tao -- 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
