linux/include
Josef Bacik 18e9e5104f Introduce freeze_super and thaw_super for the fsfreeze ioctl
Currently the way we do freezing is by passing sb>s_bdev to freeze_bdev and then
letting it do all the work.  But freezing is more of an fs thing, and doesn't
really have much to do with the bdev at all, all the work gets done with the
super.  In btrfs we do not populate s_bdev, since we can have multiple bdev's
for one fs and setting s_bdev makes removing devices from a pool kind of tricky.
This means that freezing a btrfs filesystem fails, which causes us to corrupt
with things like tux-on-ice which use the fsfreeze mechanism.  So instead of
populating sb->s_bdev with a random bdev in our pool, I've broken the actual fs
freezing stuff into freeze_super and thaw_super.  These just take the
super_block that we're freezing and does the appropriate work.  It's basically
just copy and pasted from freeze_bdev.  I've then converted freeze_bdev over to
use the new super helpers.  I've tested this with ext4 and btrfs and verified
everything continues to work the same as before.

The only new gotcha is multiple calls to the fsfreeze ioctl will return EBUSY if
the fs is already frozen.  I thought this was a better solution than adding a
freeze counter to the super_block, but if everybody hates this idea I'm open to
suggestions.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21 18:31:18 -04:00
..
acpi ACPICA: Update version to 20100428. 2010-05-06 03:05:54 -04:00
asm-generic kdb: core for kgdb back end (2 of 2) 2010-05-20 21:04:21 -05:00
crypto
drm Merge branch 'drm-for-2.6.35' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2010-05-21 11:14:52 -07:00
keys
linux Introduce freeze_super and thaw_super for the fsfreeze ioctl 2010-05-21 18:31:18 -04:00
math-emu
media V4L/DVB: v4l2-subdev.h: Add support for enum_dv_preset 2010-05-19 12:59:01 -03:00
mtd
net ipv6: Replace inet6_ifaddr->dead with state 2010-05-18 15:36:06 -07:00
pcmcia pcmcia: remove unused mem_op.h 2010-05-10 10:23:20 +02:00
rdma IB/core: Add support for masked atomic operations 2010-04-21 16:37:48 -07:00
rxrpc
scsi [SCSI] libfc: Move the port_id into lport 2010-05-16 22:22:34 -04:00
sound Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6 2010-05-20 09:41:44 -07:00
trace Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2010-05-21 07:19:18 -07:00
video
xen 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
Kbuild