linux.git/fs/block_dev.c, branch v2.6.33

freeze_bdev: don't deactivate successfully frozen MS_RDONLY sb

2010-02-07T08:06:21+00:00

Thanks Thomas and Christoph for testing and review.
I removed 'smp_wmb()' before up_write from the previous patch,
since up_write() should have necessary ordering constraints.
(I.e. the change of s_frozen is visible to others after up_write)
I'm quite sure the change is harmless but if you are uncomfortable
with Tested-by/Reviewed-by on the modified patch, please remove them.

If MS_RDONLY, freeze_bdev should just up_write(s_umount) instead of
deactivate_locked_super().
Also, keep sb->s_frozen consistent so that remount can check the frozen state.

Otherwise a crash reported here can happen:
http://lkml.org/lkml/2010/1/16/37
http://lkml.org/lkml/2010/1/28/53

This patch should be applied for 2.6.32 stable series, too.

Reviewed-by: Christoph Hellwig 
Tested-by: Thomas Backlund 
Signed-off-by: Jun'ichi Nomura 
Cc: stable@kernel.org
Signed-off-by: Al Viro

Merge branch 'for-linus' into for-2.6.33

2009-11-03T20:14:39+00:00

Conflicts:
	block/cfq-iosched.c

Signed-off-by: Jens Axboe

blkdev: flush disk cache on ->fsync

2009-10-29T13:14:04+00:00

Currently there is no barrier support in the block device code.  That
means we cannot guarantee any sort of data integerity when using the
block device node with dis kwrite caches enabled.  Using the raw block
device node is a typical use case for virtualization (and I assume
databases, too).  This patch changes block_fsync to issue a cache flush
and thus make fsync on block device nodes actually useful.

Note that in mainline we would also need to add such code to the
->aio_write method for O_SYNC handling, but assuming that Jan's patch
series for the O_SYNC rewrite goes in it will also call into ->fsync
for 2.6.32.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: use after free bug in __blkdev_get

2009-10-26T14:27:11+00:00

commit 0762b8bde9729f10f8e6249809660ff2ec3ad735
(from 14 months ago) introduced a use-after-free bug which has just
recently started manifesting in my md testing.
I tried git bisect to find out what caused the bug to start
manifesting, and it could have been the recent change to
blk_unregister_queue (48c0d4d4c04) but the results were inconclusive.

This patch certainly fixes my symptoms and looks correct as the two
calls are now in the same order as elsewhere in that function.

Signed-off-by: NeilBrown 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

freeze_bdev: grab active reference to frozen superblocks

2009-09-24T11:47:41+00:00

Currently we held s_umount while a filesystem is frozen, despite that we
might return to userspace and unlock it from a different process.  Instead
grab an active reference to keep the file system busy and add an explicit
check for frozen filesystems in remount and reject the remount instead
of blocking on s_umount.

Add a new get_active_super helper to super.c for use by freeze_bdev that
grabs an active reference to a superblock from a given block device.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

freeze_bdev: kill bd_mount_sem

2009-09-24T11:47:39+00:00

Now that we have the freeze count there is not much reason for bd_mount_sem
anymore.  The actual freeze/thaw operations are serialized using the
bd_fsfreeze_mutex, and the only other place we take bd_mount_sem is
get_sb_bdev which tries to prevent mounting a filesystem while the block
device is frozen.  Instead of add a check for bd_fsfreeze_count and
return -EBUSY if a filesystem is frozen.  While that is a change in user
visible behaviour a failing mount is much better for this case rather
than having the mount process stuck uninterruptible for a long time.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

const: make block_device_operations const

2009-09-22T14:17:25+00:00

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fs: remove bdev->bd_inode_backing_dev_info

2009-09-16T13:16:18+00:00

It has been unused since it was introduced in:

commit 520808bf20e90fdbdb320264ba7dd5cf9d47dcac
Author: Andrew Morton 
Date:   Fri May 21 00:46:17 2004 -0700

    [PATCH] block device layer: separate backing_dev_info infrastructure

So lets just kill it.

Acked-by: Jan Kara 
Signed-off-by: Jens Axboe

vfs: Rename generic_file_aio_write_nolock

2009-09-14T15:08:15+00:00

generic_file_aio_write_nolock() is now used only by block devices and raw
character device. Filesystems should use __generic_file_aio_write() in case
generic_file_aio_write() doesn't suit them. So rename the function to
blkdev_aio_write() and move it to fs/blockdev.c.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jan Kara

PM / Hibernate: Replace bdget call with simple atomic_inc of i_count

2009-07-29T19:07:55+00:00

Create bdgrab().  This function copies an existing reference to a
block_device.  It is safe to call from any context.

Hibernation code wishes to copy a reference to the active swap device.
Right now it calls bdget() under a spinlock, but this is wrong because
bdget() can sleep.  It doesn't need a full bdget() because we already
hold a reference to active swap devices (and the spinlock protects
against swapoff).

Fixes http://bugzilla.kernel.org/show_bug.cgi?id=13827

Signed-off-by: Alan Jenkins 
Signed-off-by: Rafael J. Wysocki