Merge Btrfs into fs/btrfs

   NOTE! This copyright does *not* cover user programs that use kernel

 services by normal system calls - this is merely considered normal use

 of the kernel, and does *not* fall under the heading of "derived work".

 Also note that the GPL below is copyrighted by the Free Software

 Foundation, but the instance of code that it refers to (the Linux

 kernel) is copyrighted by me and others who actually wrote it.

 Also note that the only valid version of the GPL as far as the kernel

 is concerned is _this_ particular version of the license (ie v2, not

 v2.2 or v3.x or whatever), unless explicitly otherwise stated.

			Linus Torvalds

----------------------------------------

		    GNU GENERAL PUBLIC LICENSE

		       Version 2, June 1991

 Copyright (C) 1989, 1991 Free Software Foundation, Inc.

                       51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 Everyone is permitted to copy and distribute verbatim copies

 of this license document, but changing it is not allowed.

			    Preamble

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Also add information on how to contact you by electronic and paper mail.

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The hypothetical commands `show w' and `show c' should show the appropriate

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mouse-clicks or menu items--whatever suits your program.

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necessary.  Here is a sample; alter the names:

  Yoyodyne, Inc., hereby disclaims all copyright interest in the program

  `Gnomovision' (which makes passes at compilers) written by James Hacker.

  <signature of Ty Coon>, 1 April 1989

  Ty Coon, President of Vice

This General Public License does not permit incorporating your program into

proprietary programs.  If your program is a subroutine library, you may

consider it more useful to permit linking proprietary applications with the

library.  If this is what you want to do, use the GNU Library General

Public License instead of this License.

Install Instructions

Btrfs puts snapshots and subvolumes into the root directory of the FS.  This

directory can only be changed by btrfsctl right now, and normal filesystem

operations do not work on it.  The default subvolume is called 'default',

and you can create files and directories in mount_point/default

Btrfs uses libcrc32c in the kernel for file and metadata checksums.  You need

to compile the kernel with:

CONFIG_LIBCRC32C=m

libcrc32c can be static as well.  Once your kernel is setup, typing make in the

btrfs module sources will build against the running kernel.  When the build is

complete:

modprobe libcrc32c

insmod btrfs.ko

The Btrfs utility programs require libuuid to build.  This can be found

in the e2fsprogs sources, and is usually available as libuuid or

e2fsprogs-devel from various distros.

Building the utilities is just make ; make install.  The programs go

into /usr/local/bin.  The commands available are:

mkfs.btrfs: create a filesystem

btrfsctl: control program to create snapshots and subvolumes:

	mount /dev/sda2 /mnt

	btrfsctl -s new_subvol_name /mnt

	btrfsctl -s snapshot_of_default /mnt/default

	btrfsctl -s snapshot_of_new_subvol /mnt/new_subvol_name

	btrfsctl -s snapshot_of_a_snapshot /mnt/snapshot_of_new_subvol

	ls /mnt

	default snapshot_of_a_snapshot snapshot_of_new_subvol

	new_subvol_name snapshot_of_default

	Snapshots and subvolumes cannot be deleted right now, but you can

	rm -rf all the files and directories inside them.

btrfsck: do a limited check of the FS extent trees.</li>

debug-tree: print all of the FS metadata in text form.  Example:

	debug-tree /dev/sda2 >& big_output_file

ifneq ($(KERNELRELEASE),)

# kbuild part of makefile

obj-m  := btrfs.o

btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \

	   file-item.o inode-item.o inode-map.o disk-io.o \

	   transaction.o bit-radix.o inode.o file.o tree-defrag.o \

	   extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \

	   extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \

	   ref-cache.o export.o tree-log.o acl.o free-space-cache.o

else

# Normal Makefile

KERNELDIR := /lib/modules/`uname -r`/build

all: version

	$(MAKE) -C $(KERNELDIR) M=`pwd` modules

version:

	bash version.sh

modules_install:

	$(MAKE) -C $(KERNELDIR) M=`pwd` modules_install

clean:

	$(MAKE) -C $(KERNELDIR) M=`pwd` clean

tester:

	$(MAKE) -C $(KERNELDIR) M=`pwd` tree-defrag.o transaction.o sysfs.o super.o root-tree.o inode-map.o inode-item.o inode.o file-item.o file.o extent_map.o disk-io.o ctree.o dir-item.o extent-tree.o

endif

* cleanup, add more error checking, get rid of BUG_ONs

* Fix ENOSPC handling

* Make allocator smarter

* add a block group to struct inode

* Do actual block accounting

* Check compat and incompat flags on the inode

* Get rid of struct ctree_path, limiting tree levels held at one time

* Add generation number to key pointer in nodes

* Add generation number to inode

* forbid cross subvolume renames and hardlinks

* Release

* Do real tree locking

* Add extent mirroring (backup copies of blocks)

* Add fancy interface to get access to incremental backups

* Add fancy striped extents to make big reads faster

* Use relocation to try and fix write errors

* Make allocator much smarter

* xattrs (directory streams for regular files)

* Scrub & defrag