linux_dsm_epyc7002/fs/btrfs
Kay Sievers 578454ff7e driver core: add devname module aliases to allow module on-demand auto-loading
This adds:
  alias: devname:<name>
to some common kernel modules, which will allow the on-demand loading
of the kernel module when the device node is accessed.

Ideally all these modules would be compiled-in, but distros seems too
much in love with their modularization that we need to cover the common
cases with this new facility. It will allow us to remove a bunch of pretty
useless init scripts and modprobes from init scripts.

The static device node aliases will be carried in the module itself. The
program depmod will extract this information to a file in the module directory:
  $ cat /lib/modules/2.6.34-00650-g537b60d-dirty/modules.devname
  # Device nodes to trigger on-demand module loading.
  microcode cpu/microcode c10:184
  fuse fuse c10:229
  ppp_generic ppp c108:0
  tun net/tun c10:200
  dm_mod mapper/control c10:235

Udev will pick up the depmod created file on startup and create all the
static device nodes which the kernel modules specify, so that these modules
get automatically loaded when the device node is accessed:
  $ /sbin/udevd --debug
  ...
  static_dev_create_from_modules: mknod '/dev/cpu/microcode' c10:184
  static_dev_create_from_modules: mknod '/dev/fuse' c10:229
  static_dev_create_from_modules: mknod '/dev/ppp' c108:0
  static_dev_create_from_modules: mknod '/dev/net/tun' c10:200
  static_dev_create_from_modules: mknod '/dev/mapper/control' c10:235
  udev_rules_apply_static_dev_perms: chmod '/dev/net/tun' 0666
  udev_rules_apply_static_dev_perms: chmod '/dev/fuse' 0666

A few device nodes are switched to statically allocated numbers, to allow
the static nodes to work. This might also useful for systems which still run
a plain static /dev, which is completely unsafe to use with any dynamic minor
numbers.

Note:
The devname aliases must be limited to the *common* and *single*instance*
device nodes, like the misc devices, and never be used for conceptually limited
systems like the loop devices, which should rather get fixed properly and get a
control node for losetup to talk to, instead of creating a random number of
device nodes in advance, regardless if they are ever used.

This facility is to hide the mess distros are creating with too modualized
kernels, and just to hide that these modules are not compiled-in, and not to
paper-over broken concepts. Thanks! :)

Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: Ian Kent <raven@themaw.net>
Signed-Off-By: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-05-25 15:08:26 -07:00
..
acl.c btrfs: constify xattr_handler 2010-05-21 18:31:18 -04:00
async-thread.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
async-thread.h Btrfs: fix deadlock on async thread startup 2009-10-05 09:44:45 -04:00
btrfs_inode.h Btrfs: add new defrag-range ioctl. 2010-03-15 11:00:10 -04:00
compat.h Btrfs: drop remaining LINUX_KERNEL_VERSION checks and compat code 2009-01-06 09:38:55 -05:00
compression.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-04-05 13:21:15 -07:00
compression.h Btrfs: Add zlib compression support 2008-10-29 14:49:59 -04:00
ctree.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-04-05 13:21:15 -07:00
ctree.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-04-05 13:21:15 -07:00
delayed-ref.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
delayed-ref.h Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE) 2009-06-10 11:29:46 -04:00
dir-item.c Btrfs: Pass transaction handle to security and ACL initialization functions 2009-12-17 12:33:34 -05:00
disk-io.c btrfs: convert to using bdi_setup_and_register() 2010-04-26 10:27:54 +02:00
disk-io.h Btrfs: leave btree locks spinning more often 2009-03-24 16:14:28 -04:00
export.c Btrfs: change how we mount subvolumes 2010-03-15 10:58:13 -04:00
export.h NFS support for btrfs - v3 2008-09-25 11:04:06 -04:00
extent_io.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-04-05 13:21:15 -07:00
extent_io.h Btrfs: cache the extent state everywhere we possibly can V2 2010-03-15 11:00:13 -04:00
extent_map.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
extent_map.h Btrfs: search for an allocation hint while filling file COW 2009-09-18 16:08:52 -04:00
extent-tree.c blkdev: generalize flags for blkdev_issue_fn functions 2010-04-28 19:47:36 +02:00
file-item.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
file.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
free-space-cache.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
free-space-cache.h Btrfs: use hybrid extents+bitmap rb tree for free space 2009-07-24 09:23:30 -04:00
hash.h Btrfs: remove crc32c.h and use libcrc32c directly. 2009-06-10 11:29:53 -04:00
inode-item.c Btrfs: check size of inode backref before adding hardlink 2009-09-24 09:17:31 -04:00
inode-map.c Btrfs: do not reuse objectid of deleted snapshot/subvol 2009-09-21 15:56:00 -04:00
inode.c btrfs: replace inode uid,gid,mode initialization with helper function 2010-05-21 18:31:23 -04:00
ioctl.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-05-15 12:55:31 -07:00
ioctl.h Btrfs: use __u64 types in ioctl.h 2010-03-16 14:24:27 -04:00
Kconfig Revert "task_struct: make journal_info conditional" 2009-12-17 13:23:24 -08:00
locking.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
locking.h Btrfs: fix spinlock assertions on UP systems 2009-03-09 11:45:38 -04:00
Makefile Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE) 2009-06-10 11:29:46 -04:00
ordered-data.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-04-05 13:21:15 -07:00
ordered-data.h Btrfs: cache ordered extent when completing io 2010-03-15 11:00:13 -04:00
orphan.c Btrfs: change how subvolumes are organized 2009-09-21 15:56:00 -04:00
print-tree.c Btrfs: remove of redundant btrfs_header_level 2009-07-22 16:52:13 -04:00
print-tree.h Btrfs: Create extent_buffer interface for large blocksizes 2008-09-25 11:03:56 -04:00
ref-cache.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
ref-cache.h Btrfs: use RB_ROOT to intialize rb_trees instead of setting rb_node to NULL 2010-03-08 16:26:50 -05:00
relocation.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
root-tree.c Btrfs: skip btrfs_release_path in btrfs_update_root and btrfs_del_root 2009-11-11 14:20:18 -05:00
struct-funcs.c Btrfs: Fix checkpatch.pl warnings 2009-01-05 21:25:51 -05:00
super.c driver core: add devname module aliases to allow module on-demand auto-loading 2010-05-25 15:08:26 -07:00
sysfs.c Driver core: Constify struct sysfs_ops in struct kobj_type 2010-03-07 17:04:49 -08:00
transaction.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-04-05 13:21:15 -07:00
transaction.h Btrfs: Avoid superfluous tree-log writeout 2009-12-15 21:24:25 -05:00
tree-defrag.c Btrfs: do extent allocation and reference count updates in the background 2009-03-24 16:14:25 -04:00
tree-log.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
tree-log.h Btrfs: avoid tree log commit when there are no changes 2009-10-13 13:35:12 -04:00
version.h Update Btrfs files for in-kernel usage 2008-09-25 15:41:59 -04:00
version.sh Btrfs: Fixes for 2.6.28-rc API changes 2008-11-19 21:17:22 -05:00
volumes.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable 2010-04-12 18:37:04 -07:00
volumes.h Btrfs: make balance code choose more wisely when relocating 2009-09-21 19:23:48 -04:00
xattr.c btrfs: constify xattr_handler 2010-05-21 18:31:18 -04:00
xattr.h btrfs: constify xattr_handler 2010-05-21 18:31:18 -04:00
zlib.c Btrfs: correct error-handling zlib error handling 2009-08-07 13:51:33 -04:00