On Thu, 14 Jun 2012 11:22:17 +0700, Ivan Shmakov wrote: > >>>>> Ryusuke Konishi writes: > >>>>> On Wed, 13 Jun 2012 23:06:54 +0700, Ivan Shmakov wrote: > >> Thus, I'm curious, are there any plans to implement “off-line” NILFS > >> resizing? > > > Implementing Off-line resizing is a bit tough task because it > > requires a user space library to read internal meta data of the nilfs > > file system and append updated blocks to it. This is almost > > equivalent to implementing kernel functions of nilfs in user land. > > > So, we have no concrete schedule now. > > ACK, thanks. > > I wonder, how complicated this task would be? In particular, do > I need to alter all the segments to resize filesystem, or only > specific ones? Also, are these internal metadata records just > “a bunch of C structs”, or something more complex? This needs at least the following tasks: 1) Update two super blocks to increase/decrease the number of total segments and the device size. (easy) 2) Update segment usage information to adjust free segment count of nilfs_sufile_header struct (sh_ncleansegs) which is written in the segment usage file. (Sadly not easy) 3) If truncating in-use segments, relocating blocks and updating disk address translation information are also needed. (very hard) For reference, a discussion on this topic is found in the archives of the list: http://marc.info/?t=128419843600003&r=1&w=2 Regards, Ryusuke Konishi -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
