Commit Graph

50 Commits

Author SHA1 Message Date
Josef Bacik aac0023c21 btrfs: move basic block_group definitions to their own header
This is prep work for moving all of the block group cache code into its
own file.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor comment updates ]
Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-09 14:59:03 +02:00
David Sterba 2ccf545e0d btrfs: get fs_info from block group in search_free_space_info
We can read fs_info from the block group cache structure and can drop it
from the parameters.  Though the transaction is also availabe, it's not
guaranteed to be non-NULL.

Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:46 +02:00
David Sterba 9b7a2440ae btrfs: get fs_info from trans in btrfs_create_tree
We can read fs_info from the transaction and can drop it from the
parameters.

Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:41 +02:00
David Sterba 6a884d7d52 btrfs: get fs_info from eb in clean_tree_block
We can read fs_info from extent buffer and can drop it from the
parameters.

Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29 19:02:30 +02:00
Johannes Thumshirn ce9f967f31 btrfs: use EXPORT_FOR_TESTS for conditionally exported functions
Several functions in BTRFS are only used inside the source file they are
declared if CONFIG_BTRFS_FS_RUN_SANITY_TESTS is not defined. However if
CONFIG_BTRFS_FS_RUN_SANITY_TESTS is defined these functions are shared
with the unit tests code.

Before the introduction of the EXPORT_FOR_TESTS macro, these functions
could not be declared as static and the compiler had a harder task when
optimizing and inlining them.

As we have EXPORT_FOR_TESTS now, use it where appropriate to support the
compiler.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-12-17 14:51:37 +01:00
Lu Fengqi ab9ce7d42b btrfs: Remove fs_info from btrfs_del_root
It can be referenced from the passed transaction handle.

Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06 13:13:00 +02:00
Nikolay Borisov ffa9a9ef2f btrfs: Remove fs_info argument from populate_free_space_tree
This function always takes a transaction handle which contains a
reference to the fs_info. Use that and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:36 +02:00
Nikolay Borisov e7355e501d btrfs: Remove fs_info argument from add_to_free_space_tree
This function takes a transaction handle which already contains a
reference to the fs_info. So use it and remove the extra function
argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:36 +02:00
Nikolay Borisov 25a356d3f6 btrfs: Remove fs_info argument from remove_from_free_space_tree
This function alreay takes a transaction handle which holds a reference
to the fs_info. Use that and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:35 +02:00
Nikolay Borisov c31683a6ef btrfs: Remove fs_info argument from __remove_from_free_space_tree
This function takes a transaction handle which holds a reference to
fs_info. So use that and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:35 +02:00
Nikolay Borisov e581168d1f btrfs: Remove fs_info argument from remove_free_space_extent
This function takes a transaction handle which already has a reference
to the fs_info. Use it and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:35 +02:00
Nikolay Borisov 5cb1782213 btrfs: Remove fs_info argument from add_free_space_extent
This function always takes a transaction handle which references the
fs_info structure. So use that and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:35 +02:00
Nikolay Borisov 85a7ef130c btrfs: Remove fs_info argument from modify_free_space_bitmap
This function already takes a transaction which has a reference to the
fs_info. So use that and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:34 +02:00
Nikolay Borisov 690d76828a btrfs: Remove fs_info argument from update_free_space_extent_count
This function already takes a transaction handle which has a reference
to the fs_info. So use that and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:34 +02:00
Nikolay Borisov 5296c2bf51 btrfs: Remove fs_info parameter from convert_free_space_to_extents
This function always takes a transaction handle which contains a
reference to fs_info. So use that and kill the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:34 +02:00
Nikolay Borisov 719fb4de55 btrfs: Remove fs_info argument from convert_free_space_to_bitmaps
This function already takes a transaction handle which contains a
reference to fs_info. So use that and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:34 +02:00
Nikolay Borisov f3f7277995 btrfs: Remove fs_info parameter from remove_block_group_free_space
This function always takes a trans handle which contains a reference to
the fs_info. Use that and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:34 +02:00
Nikolay Borisov 4457c1c702 btrfs: Remove fs_info argument from add_new_free_space
This function also takes a btrfs_block_group_cache which contains a
referene to the fs_info. So use that and remove the extra argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:33 +02:00
Nikolay Borisov 66afee1848 btrfs: Remove fs_info parameter from add_new_free_space_info
This function already takes trans handle from where fs_info can be
referenced. Remove the redundant parameter.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:33 +02:00
Nikolay Borisov 2d5cffa1b0 btrfs: Remove fs_info argument from __add_to_free_space_tree
This function already takes a transaction handle which contains a
reference to fs_info.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:33 +02:00
Nikolay Borisov 9a7e0f9284 btrfs: Remove fs_info argument from __add_block_group_free_space
This function already takes a transaction handle which has a reference
to the fs_info.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:33 +02:00
Nikolay Borisov e4e0711cd9 btrfs: Remove fs_info argument from add_block_group_free_space
We also pass in a transaction handle which has a reference to the
fs_info. Just remove the extraneous argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:33 +02:00
Howard McLauchlan a565971ff3 btrfs: optimize free space tree bitmap conversion
Presently, convert_free_space_to_extents() does a linear scan of the
bitmap. We can speed this up with find_next_{bit,zero_bit}_le().

This patch replaces the linear scan with find_next_{bit,zero_bit}_le().
Testing shows a 20-33% decrease in execution time for
convert_free_space_to_extents().

Since we change bitmap to be unsigned long, we have to do some casting
for the bitmap cursor. In le_bitmap_set() it makes sense to use u8, as
we are doing bit operations. Everywhere else, we're just using it for
pointer arithmetic and not directly accessing it, so char seems more
appropriate.

Suggested-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:18 +02:00
Howard McLauchlan 6faa8f475e btrfs: clean up le_bitmap_{set, clear}()
le_bitmap_set() is only used by free-space-tree, so move it there and
make it static. le_bitmap_clear() is not used, so remove it.

Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28 18:07:18 +02:00
David Sterba c1d7c514f7 btrfs: replace GPL boilerplate by SPDX -- sources
Remove GPL boilerplate text (long, short, one-line) and keep the rest,
ie. personal, company or original source copyright statements. Add the
SPDX header.

Signed-off-by: David Sterba <dsterba@suse.com>
2018-04-12 16:29:51 +02:00
Gu JinXiang 7ce311d552 btrfs: use reada direction enum instead of constant value in load_free_space_tree
load_free_space_tree calls either function load_free_space_bitmaps or
load_free_space_extents. And either of those two will lead to call
btrfs_next_item.  So in function load_free_space_tree, use READA_FORWARD
to read forward ahead.

This also changes the value from READA_BACK to READA_FORWARD, since
according to the logic, it should reada_for_search forward, not
backward.

Signed-off-by: Gu JinXiang <gujx@cn.fujitsu.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2018-03-26 15:09:37 +02:00
Gu Jinxiang 019599ada7 btrfs: use reada direction enum instead of constant value in populate_free_space_tree
populate_free_space_tree calls function btrfs_search_slot_for_read with
parameter int find_higher = 1, it means that, if no exact match is
found, then use the next higher item.  So in function
populate_free_space_tree, use READA_FORWARD to read forward ahead.

This also changes the value from READA_BACK to READA_FORWARD, since
according to the logic, it should reada_for_search forward, not
backward.

Signed-off-by: Gu JinXiang <gujx@cn.fujitsu.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2018-03-26 15:09:37 +02:00
Christos Gkekas 9e882d6d05 btrfs: Clean up unused variables in free-space-tree.c
Remove variables 'start' and 'end', which are set but never used.

Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2017-10-30 12:27:59 +01:00
Jeff Mahoney 1cd5447eb6 btrfs: pass fs_info to btrfs_del_root instead of tree_root
btrfs_del_roots always uses the tree_root.  Let's pass fs_info instead.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-21 17:49:54 +02:00
Omar Sandoval 25ff17e82f Btrfs: use memalloc_nofs and kvzalloc() for free space tree bitmaps
First, instead of open-coding the vmalloc() fallback, use the new
kvzalloc() helper. Second, use memalloc_nofs_{save,restore}() instead of
GFP_NOFS, as vmalloc() uses some GFP_KERNEL allocations internally which
could lead to deadlocks.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2017-06-19 18:26:01 +02:00
Sahil Kang 0bef71093d btrfs: Remove unnecessary branching in free-space-tree.c
Both btrfs_create_free_space_tree and btrfs_clear_free_space_tree
contain:

  if (ret)
          return ret;

  return 0;

The if statement is only false when ret equals zero, and since we return
zero in such cases, we can safely remove the branching.

Signed-off-by: Sahil Kang <sahil.kang@asilaycomputing.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2017-06-19 18:25:59 +02:00
Michal Hocko 19809c2da2 mm, vmalloc: use __GFP_HIGHMEM implicitly
__vmalloc* allows users to provide gfp flags for the underlying
allocation.  This API is quite popular

  $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l
  77

The only problem is that many people are not aware that they really want
to give __GFP_HIGHMEM along with other flags because there is really no
reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages
which are mapped to the kernel vmalloc space.  About half of users don't
use this flag, though.  This signals that we make the API unnecessarily
too complex.

This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to
be mapped to the vmalloc space.  Current users which add __GFP_HIGHMEM
are simplified and drop the flag.

Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Cristopher Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08 17:15:13 -07:00
David Sterba 7c302b49dd btrfs: remove unused parameter from clean_tree_block
Added but never needed.

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2017-02-17 12:03:51 +01:00
Jeff Mahoney 3a45bb207e btrfs: remove root parameter from transaction commit/end routines
Now we only use the root parameter to print the root objectid in
a tracepoint.  We can use the root parameter from the transaction
handle for that.  It's also used to join the transaction with
async commits, so we remove the comment that it's just for checking.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06 16:07:00 +01:00
Jeff Mahoney 0b246afa62 btrfs: root->fs_info cleanup, add fs_info convenience variables
In routines where someptr->fs_info is referenced multiple times, we
introduce a convenience variable.  This makes the code considerably
more readable.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06 16:06:59 +01:00
Jeff Mahoney da17066c40 btrfs: pull node/sector/stripe sizes out of root and into fs_info
We track the node sizes per-root, but they never vary from the values
in the superblock.  This patch messes with the 80-column style a bit,
but subsequent patches to factor out root->fs_info into a convenience
variable fix it up again.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06 16:06:58 +01:00
Chris Mason d9ed71e545 Merge branch 'fst-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.9
Signed-off-by: Chris Mason <clm@fb.com>
2016-10-12 13:16:00 -07:00
Omar Sandoval 6675df311d Btrfs: catch invalid free space trees
There are two separate issues that can lead to corrupted free space
trees.

1. The free space tree bitmaps had an endianness issue on big-endian
   systems which is fixed by an earlier patch in this series.
2. btrfs-progs before v4.7.3 modified filesystems without updating the
   free space tree.

To catch both of these issues at once, we need to force the free space
tree to be rebuilt. To do so, add a FREE_SPACE_TREE_VALID compat_ro bit.
If the bit isn't set, we know that it was either produced by a broken
big-endian kernel or may have been corrupted by btrfs-progs.

This also provides us with a way to add rudimentary read-write support
for the free space tree to btrfs-progs: it can just clear this bit and
have the kernel rebuild the free space tree.

Cc: stable@vger.kernel.org # 4.5+
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-10-03 18:52:14 +02:00
Omar Sandoval 2fe1d55134 Btrfs: fix free space tree bitmaps on big-endian systems
In convert_free_space_to_{bitmaps,extents}(), we buffer the free space
bitmaps in memory and copy them directly to/from the extent buffers with
{read,write}_extent_buffer(). The extent buffer bitmap helpers use byte
granularity, which is equivalent to a little-endian bitmap. This means
that on big-endian systems, the in-memory bitmaps will be written to
disk byte-swapped. To fix this, use byte-granularity for the bitmaps in
memory.

Fixes: a5ed918285 ("Btrfs: implement the free space B-tree")
Cc: stable@vger.kernel.org # 4.5+
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-10-03 18:52:14 +02:00
Jeff Mahoney ab8d0fc48d btrfs: convert pr_* to btrfs_* where possible
For many printks, we want to know which file system issued the message.

This patch converts most pr_* calls to use the btrfs_* versions instead.
In some cases, this means adding plumbing to allow call sites access to
an fs_info pointer.

fs/btrfs/check-integrity.c is left alone for another day.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26 19:37:04 +02:00
Jeff Mahoney 5d163e0e68 btrfs: unsplit printed strings
CodingStyle chapter 2:
"[...] never break user-visible strings such as printk messages,
because that breaks the ability to grep for them."

This patch unsplits user-visible strings.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26 18:08:44 +02:00
Josef Bacik afcdd129e0 Btrfs: add a flags field to btrfs_fs_info
We have a lot of random ints in btrfs_fs_info that can be put into flags.  This
is mostly equivalent with the exception of how we deal with quota going on or
off, now instead we set a flag when we are turning it on or off and deal with
that appropriately, rather than just having a pending state that the current
quota_enabled gets set to.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26 17:59:49 +02:00
Jeff Mahoney 66642832f0 btrfs: btrfs_abort_transaction, drop root parameter
__btrfs_abort_transaction doesn't use its root parameter except to
obtain an fs_info pointer.  We can obtain that from trans->root->fs_info
for now and from trans->fs_info in a later patch.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2016-07-26 13:54:26 +02:00
Chris Mason e410e34fad Revert "btrfs: synchronize incompat feature bits with sysfs files"
This reverts commit 14e46e0495.

This ends up doing sysfs operations from deep in balance (where we
should be GFP_NOFS) and under heavy balance load, we're making races
against sysfs internals.

Revert it for now while we figure things out.

Signed-off-by: Chris Mason <clm@fb.com>
2016-01-29 08:19:37 -08:00
Chris Mason e1c0ebad3f btrfs: don't use GFP_HIGHMEM for free-space-tree bitmap kzalloc
This was copied incorrectly from the __vmalloc call.

Signed-off-by: Chris Mason <clm@fb.com>
2016-01-27 07:05:49 -08:00
Chris Mason d32a4e3434 Merge branch 'dev/fst-followup' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.5 2016-01-27 05:48:23 -08:00
David Sterba 79b134a22b btrfs: tweak free space tree bitmap allocation
The requested bitmap size varies, observed numbers were < 4K up to 16K.
Using vmalloc unconditionally would be too heavy, we'll try contiguous
allocations first and fall back to vmalloc if there's no contig memory.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-22 17:16:18 +01:00
David Sterba 14e46e0495 btrfs: synchronize incompat feature bits with sysfs files
The files under /sys/fs/UUID/features get out of sync with the actual
incompat bits set for the filesystem if they change after mount (eg. the
LZO compression).

Synchronize the feature bits with the sysfs files representing them
right after we set/clear them.

Signed-off-by: David Sterba <dsterba@suse.com>
2016-01-21 18:54:41 +01:00
Chris Mason 511711af91 btrfs: don't run delayed references while we are creating the free space tree
This is a short term solution to make sure btrfs_run_delayed_refs()
doesn't change the extent tree while we are scanning it to create the
free space tree.

Longer term we need to synchronize scanning the block groups one by one,
similar to what happens during a balance.

Signed-off-by: Chris Mason <clm@fb.com>
2015-12-30 07:52:35 -08:00
Omar Sandoval a5ed918285 Btrfs: implement the free space B-tree
The free space cache has turned out to be a scalability bottleneck on
large, busy filesystems. When the cache for a lot of block groups needs
to be written out, we can get extremely long commit times; if this
happens in the critical section, things are especially bad because we
block new transactions from happening.

The main problem with the free space cache is that it has to be written
out in its entirety and is managed in an ad hoc fashion. Using a B-tree
to store free space fixes this: updates can be done as needed and we get
all of the benefits of using a B-tree: checksumming, RAID handling,
well-understood behavior.

With the free space tree, we get commit times that are about the same as
the no cache case with load times slower than the free space cache case
but still much faster than the no cache case. Free space is represented
with extents until it becomes more space-efficient to use bitmaps,
giving us similar space overhead to the free space cache.

The operations on the free space tree are: adding and removing free
space, handling the creation and deletion of block groups, and loading
the free space for a block group. We can also create the free space tree
by walking the extent tree and clear the free space tree.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-12-17 12:16:47 -08:00