Subject: [PATCH V1 00/17] ext4: Add inline data support.
Date: Wednesday 26th October 2011 07:32:24 UTC (over 5 years ago)
Hi Ted, Andreas and list, This is my 1st attempt to add inline data support to ext4 inode. For more information about the background, please refer to the thread http://marc.info/?l=linux-ext4&m=131715205428067&w=2 When I sent out the RFC on Sep.27, Andreas suggested that we can use the space of xattr to put inline data. So this is the 1st version using that method. It should be easy to change if we decide to use other places in inode(e.g the unused extent space) since all the inline data manipulation function is wrapped with function like ext4_*_inline_data. Currently I use 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. This is only a V1 and there are still something to do(e.g. I am thinking of using unused extent space), but I'd like to send it out earlier so that it can be reviewed ASAP. Some simple tests shows that with a linux-3.0 vanilla source, the new dir can save 1% disk space. For my "/usr", it can save about 3.2% spaces. I guess for volume with future bigalloc support, it should save more space for us for small dir. I also run some other tests and it seems the code is OK for a try. I haven't found a good test cases that can test the small file/dir(tens of bytes in my case) performance where inline data should have some good number. Any comments are welcomed. git diff --stat fs/ext4/dir.c | 117 ++++++++++- fs/ext4/ext4.h | 15 +- fs/ext4/ialloc.c | 4 + fs/ext4/inode.c | 583 +++++++++++++++++++++++++++++++++++++++++++++++--- fs/ext4/namei.c | 629 +++++++++++++++++++++++++++++++++++++++++++++--------- fs/ext4/xattr.c | 216 +++++++++++++++++++ fs/ext4/xattr.h | 68 ++++++ 7 files changed, 1489 insertions(+), 143 deletions(-) Thanks Tao