XFS status update for May 2012

[Christoph Hellwig <hch@infradead.org>]

May saw the release of Linux 3.4, including a decent sized XFS update.
Remarkable XFS features in Linux 3.4 include moving over all metadata
updates to use transactions, the addition of a work queue for the
low-level allocator code to avoid stack overflows due to extreme stack
use in the Linux VM/VFS call chain, better xattr operation tracing,
fixes for a long-standing but hard to hit deadlock when using the XFS
real time subvolume, and big improvements in disk quota scalability.

The final diffstat for XFS in Linux 3.4 is:

 61 files changed, 1692 insertions(+), 2356 deletions(-)

In the meantime the merge window for Linux 3.5 opened, and another large
update has been merged into Linus' tree.  Interesting changes in Linux
3.5-rc1 include improved error handling on buffer write failures,
a drastic reduction of locking overhead when doing high-IOPS direct I/O,
removal of the old xfsbufd daemon in favor of writing most run-time
metadata from the xfsaild daemon, deferral of CIL pushes to decouple
user space metadata I/O from log writeback, and last but not least the
addition of the SEEK_DATA/SEEK_HOLE lseek arguments that allow user space
programs to deal with sparse files efficiently. Traffic on the mailing list
has been a bit quiet in May, mostly focusing on a wide range of bug fixes,
but little new features.

On the user space side xfs_repair saw a few bug fixes posted to the list
that didn't make it to the repository yet, while xfstests saw it's usual
amount of minor bug fixes.