linux-toradex.git/drivers/md/persistent-data/dm-btree-internal.h, branch v3.10.62

dm btree: fix a recursion depth bug in btree walking code

2014-11-21T17:22:53+00:00

commit 9b460d3699324d570a4d4161c3741431887f102f upstream.

The walk code was using a 'ro_spine' to hold it's locked btree nodes.
But this data structure is designed for the rolling lock scheme, and
as such automatically unlocks blocks that are two steps up the call
chain.  This is not suitable for the simple recursive walk algorithm,
which retraces its steps.

This code is only used by the persistent array code, which in turn is
only used by dm-cache.  In order to trigger it you need to have a
mapping tree that is more than 2 levels deep; which equates to 8-16
million cache blocks.  For instance a 4T ssd with a very small block
size of 32k only just triggers this bug.

The fix just places the locked blocks on the stack, and stops using
the ro_spine altogether.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm persistent data: add btree_walk

2013-03-01T22:45:50+00:00

Add dm_btree_walk to iterate through the contents of a btree.
This will be used by the dm cache target.

Signed-off-by: Joe Thornber 
Signed-off-by: Alasdair G Kergon

dm persistent data: rename node to btree_node

2012-12-21T20:23:30+00:00

This patch fixes a compilation failure on sparc32 by renaming struct node.

struct node is already defined in include/linux/node.h. On sparc32, it
happens to be included through other dependencies and persistent-data
doesn't compile because of conflicting declarations.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Signed-off-by: Alasdair G Kergon

dm persistent data: remove redundant value_size arg from value_ptr

2012-03-28T17:41:25+00:00

Now that the value_size is held within every node of the btrees we can
remove this argument from value_ptr().

For the last few months a BUG_ON has been checking this argument is
the same as that held in the node.  No issues were reported.  So this
is a safe change.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm: add persistent data library

2011-10-31T20:19:11+00:00

The persistent-data library offers a re-usable framework for the storage
and management of on-disk metadata in device-mapper targets.

It's used by the thin-provisioning target in the next patch and in an
upcoming hierarchical storage target.

For further information, please read
Documentation/device-mapper/persistent-data.txt

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon