btrfs: raid56: enable subpage support for RAID56

Now the btrfs RAID56 infrastructure has migrated to use sector_ptr
interface, it should be safe to enable subpage support for RAID56.

Signed-off-by:

btrfs: raid56: enable subpage support for RAID56

Now the btrfs RAID56 infrastructure has migrated to use sector_ptr
interface, it should be safe to enable subpage support for RAID56.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: do not return errors from btrfs_submit_metadata_bio

btrfs_submit_metadata_bio already calls ->bi_end_io on error and the
caller must ignore the return value, so remove it.

Reviewed-by: Qu We

btrfs: do not return errors from btrfs_submit_metadata_bio

btrfs_submit_metadata_bio already calls ->bi_end_io on error and the
caller must ignore the return value, so remove it.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: remove unused bio_flags argument to btrfs_submit_metadata_bio

This argument is unused since commit 953651eb308f ("btrfs: factor out
helper adding a page to bio") and commit 1b36294a6cd5 ("btr

btrfs: remove unused bio_flags argument to btrfs_submit_metadata_bio

This argument is unused since commit 953651eb308f ("btrfs: factor out
helper adding a page to bio") and commit 1b36294a6cd5 ("btrfs: call
submit_bio_hook directly for metadata pages") reworked the way metadata
bio submission is handled.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: use a read/write lock for protecting the block groups tree

Currently we use a spin lock to protect the red black tree that we use to
track block groups. Most accesses to that tree are actuall

btrfs: use a read/write lock for protecting the block groups tree

Currently we use a spin lock to protect the red black tree that we use to
track block groups. Most accesses to that tree are actually read only and
for large filesystems, with thousands of block groups, it actually has
a bad impact on performance, as concurrent read only searches on the tree
are serialized.

Read only searches on the tree are very frequent and done when:

1) Pinning and unpinning extents, as we need to lookup the respective
block group from the tree;

2) Freeing the last reference of a tree block, regardless if we pin the
underlying extent or add it back to free space cache/tree;

3) During NOCOW writes, both buffered IO and direct IO, we need to check
if the block group that contains an extent is read only or not and to
increment the number of NOCOW writers in the block group. For those
operations we need to search for the block group in the tree.
Similarly, after creating the ordered extent for the NOCOW write, we
need to decrement the number of NOCOW writers from the same block
group, which requires searching for it in the tree;

4) Decreasing the number of extent reservations in a block group;

5) When allocating extents and freeing reserved extents;

6) Adding and removing free space to the free space tree;

7) When releasing delalloc bytes during ordered extent completion;

8) When relocating a block group;

9) During fitrim, to iterate over the block groups;

10) etc;

Write accesses to the tree, to add or remove block groups, are much less
frequent as they happen only when allocating a new block group or when
deleting a block group.

We also use the same spin lock to protect the list of currently caching
block groups. Additions to this list are made when we need to cache a
block group, because we don't have a free space cache for it (or we have
but it's invalid), and removals from this list are done when caching of
the block group's free space finishes. These cases are also not very
common, but when they happen, they happen only once when the filesystem
is mounted.

So switch the lock that protects the tree of block groups from a spinning
lock to a read/write lock.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: use rbtree with leftmost node cached for tracking lowest block group

We keep track of the start offset of the block group with the lowest start
offset at fs_info->first_logical_byte. This req

btrfs: use rbtree with leftmost node cached for tracking lowest block group

We keep track of the start offset of the block group with the lowest start
offset at fs_info->first_logical_byte. This requires explicitly updating
that field every time we add, delete or lookup a block group to/from the
red black tree at fs_info->block_group_cache_tree.

Since the block group with the lowest start address happens to always be
the one that is the leftmost node of the tree, we can use a red black tree
that caches the left most node. Then when we need the start address of
that block group, we can just quickly get the leftmost node in the tree
and extract the start offset of that node's block group. This avoids the
need to explicitly keep track of that address in the dedicated member
fs_info->first_logical_byte, and it also allows the next patch in the
series to switch the lock that protects the red black tree from a spin
lock to a read/write lock - without this change it would be tricky
because block group searches also update fs_info->first_logical_byte.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: check-integrity: split submit_bio from btrfsic checking

Require a separate call to the integrity checking helpers from the
actual bio submission.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed

btrfs: check-integrity: split submit_bio from btrfsic checking

Require a separate call to the integrity checking helpers from the
actual bio submission.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: remove unnecessary type casts

Explicit type casts are not necessary when it's void* to another pointer
type.

Signed-off-by: Yu Zhe <yuzhe@nfschina.com>
Reviewed-by: David Sterba <dsterba@sus

btrfs: remove unnecessary type casts

Explicit type casts are not necessary when it's void* to another pointer
type.

Signed-off-by: Yu Zhe <yuzhe@nfschina.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: expand subpage support to any PAGE_SIZE > 4K

With the recent change in metadata handling, we can handle metadata in
the following cases:

- nodesize < PAGE_SIZE and sectorsize < PAGE_SIZE
G

btrfs: expand subpage support to any PAGE_SIZE > 4K

With the recent change in metadata handling, we can handle metadata in
the following cases:

- nodesize < PAGE_SIZE and sectorsize < PAGE_SIZE
Go subpage routine for both metadata and data.

- nodesize < PAGE_SIZE and sectorsize >= PAGE_SIZE
Invalid case for now. As we require nodesize >= sectorsize.

- nodesize >= PAGE_SIZE and sectorsize < PAGE_SIZE
Go subpage routine for data, but regular page routine for metadata.

- nodesize >= PAGE_SIZE and sectorsize >= PAGE_SIZE
Go regular page routine for both metadata and data.

Now we can handle any sectorsize < PAGE_SIZE, plus the existing
sectorsize == PAGE_SIZE support.

But here we introduce an artificial limit, any PAGE_SIZE > 4K case, we
will only support 4K and PAGE_SIZE as sector size.

The idea here is to reduce the test combinations, and push 4K as the
default standard in the future.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: make nodesize >= PAGE_SIZE case to reuse the non-subpage routine

The reason why we only support 64K page size for subpage is, for 64K
page size we can ensure no matter what the nodesize is, w

btrfs: make nodesize >= PAGE_SIZE case to reuse the non-subpage routine

The reason why we only support 64K page size for subpage is, for 64K
page size we can ensure no matter what the nodesize is, we can fit it
into one page.

When other page size come, especially like 16K, the limitation is a bit
limiting.

To remove such limitation, we allow nodesize >= PAGE_SIZE case to go the
non-subpage routine. By this, we can allow 4K sectorsize on 16K page
size.

Although this introduces another smaller limitation, the metadata can
not cross page boundary, which is already met by most recent mkfs.

Another small improvement is, we can avoid the overhead for metadata if
nodesize >= PAGE_SIZE.
For 4K sector size and 64K page size/node size, or 4K sector size and
16K page size/node size, we don't need to allocate extra memory for the
metadata pages.

Please note that, this patch will not yet enable other page size support
yet.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: tree-checker: check extent buffer owner against owner rootid

Btrfs doesn't check whether the tree block respects the root owner.
This means, if a tree block referred by a parent in extent tre

btrfs: tree-checker: check extent buffer owner against owner rootid

Btrfs doesn't check whether the tree block respects the root owner.
This means, if a tree block referred by a parent in extent tree, but has
owner of 5, btrfs can still continue reading the tree block, as long as
it doesn't trigger other sanity checks.

Normally this is fine, but combined with the empty tree check in
check_leaf(), if we hit an empty extent tree, but the root node has
csum tree owner, we can let such extent buffer to sneak in.

Shrink the hole by:

- Do extra eb owner check at tree read time

- Make sure the root owner extent buffer exactly matches the root id.

Unfortunately we can't yet completely patch the hole, there are several
call sites can't pass all info we need:

- For reloc/log trees
Their owner is key::offset, not key::objectid.
We need the full root key to do that accurate check.

For now, we just skip the ownership check for those trees.

- For add_data_references() of relocation
That call site doesn't have any parent/ownership info, as all the
bytenrs are all from btrfs_find_all_leafs().

- For direct backref items walk
Direct backref items records the parent bytenr directly, thus unlike
indirect backref item, we don't do a full tree search.

Thus in that case, we don't have full parent owner to check.

For the later two cases, they all pass 0 as @owner_root, thus we can
skip those cases if @owner_root is 0.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: remove trivial wrapper btrfs_read_buffer()

The function btrfs_read_buffer() is useless, it just calls
btree_read_extent_buffer_pages() with exactly the same arguments.

So remove it and renam

btrfs: remove trivial wrapper btrfs_read_buffer()

The function btrfs_read_buffer() is useless, it just calls
btree_read_extent_buffer_pages() with exactly the same arguments.

So remove it and rename btree_read_extent_buffer_pages() to
btrfs_read_extent_buffer(), which is a shorter name, has the "btrfs_"
prefix (since it's used outside disk-io.c) and the name is clear enough
about what it does.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: Convert to release_folio

I've only converted the outer layers of the btrfs release_folio paths
to use folios; the use of folios should be pushed further down into
btrfs from here.

Signed-off

btrfs: Convert to release_folio

I've only converted the outer layers of the btrfs release_folio paths
to use folios; the use of folios should be pushed further down into
btrfs from here.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>

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btrfs: force v2 space cache usage for subpage mount

[BUG]
For a 4K sector sized btrfs with v1 cache enabled and only mounted on
systems with 4K page size, if it's mounted on subpage (64K page size)

btrfs: force v2 space cache usage for subpage mount

[BUG]
For a 4K sector sized btrfs with v1 cache enabled and only mounted on
systems with 4K page size, if it's mounted on subpage (64K page size)
systems, it can cause the following warning on v1 space cache:

BTRFS error (device dm-1): csum mismatch on free space cache
BTRFS warning (device dm-1): failed to load free space cache for block group 84082688, rebuilding it now

Although not a big deal, as kernel can rebuild it without problem, such
warning will bother end users, especially if they want to switch the
same btrfs seamlessly between different page sized systems.

[CAUSE]
V1 free space cache is still using fixed PAGE_SIZE for various bitmap,
like BITS_PER_BITMAP.

Such hard-coded PAGE_SIZE usage will cause various mismatch, from v1
cache size to checksum.

Thus kernel will always reject v1 cache with a different PAGE_SIZE with
csum mismatch.

[FIX]
Although we should fix v1 cache, it's already going to be marked
deprecated soon.

And we have v2 cache based on metadata (which is already fully subpage
compatible), and it has almost everything superior than v1 cache.

So just force subpage mount to use v2 cache on mount.

Reported-by: Matt Corallo <blnxfsl@bluematt.me>
CC: stable@vger.kernel.org # 5.15+
Link: https://lore.kernel.org/linux-btrfs/61aa27d1-30fc-c1a9-f0f4-9df544395ec3@bluematt.me/
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: zoned: use dedicated lock for data relocation

Currently, we use btrfs_inode_{lock,unlock}() to grant an exclusive
writeback of the relocation data inode in
btrfs_zoned_data_reloc_{lock,unlock

btrfs: zoned: use dedicated lock for data relocation

Currently, we use btrfs_inode_{lock,unlock}() to grant an exclusive
writeback of the relocation data inode in
btrfs_zoned_data_reloc_{lock,unlock}(). However, that can cause a deadlock
in the following path.

Thread A takes btrfs_inode_lock() and waits for metadata reservation by
e.g, waiting for writeback:

prealloc_file_extent_cluster()
- btrfs_inode_lock(&inode->vfs_inode, 0);
- btrfs_prealloc_file_range()
...
- btrfs_replace_file_extents()
- btrfs_start_transaction
...
- btrfs_reserve_metadata_bytes()

Thread B (e.g, doing a writeback work) needs to wait for the inode lock to
continue writeback process:

do_writepages
- btrfs_writepages
- extent_writpages
- btrfs_zoned_data_reloc_lock(BTRFS_I(inode));
- btrfs_inode_lock()

The deadlock is caused by relying on the vfs_inode's lock. By using it, we
introduced unnecessary exclusion of writeback and
btrfs_prealloc_file_range(). Also, the lock at this point is useless as we
don't have any dirty pages in the inode yet.

Introduce fs_info->zoned_data_reloc_io_lock and use it for the exclusive
writeback.

Fixes: 35156d852762 ("btrfs: zoned: only allow one process to add pages to a relocation inode")
CC: stable@vger.kernel.org # 5.16.x: 869f4cdc73f9: btrfs: zoned: encapsulate inode locking for zoned relocation
CC: stable@vger.kernel.org # 5.16.x
CC: stable@vger.kernel.org # 5.17
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

block: add a bdev_write_cache helper

Add a helper to check the write cache flag based on the block_device
instead of having to poke into the block layer internal request_queue.

Signed-off-by: Chris

block: add a bdev_write_cache helper

Add a helper to check the write cache flag based on the block_device
instead of having to poke into the block layer internal request_queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

btrfs: simplify ->flush_bio handling

Use and embedded bios that is initialized when used instead of
bio_kmalloc plus bio_reset.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Ster

btrfs: simplify ->flush_bio handling

Use and embedded bios that is initialized when used instead of
bio_kmalloc plus bio_reset.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220406061228.410163-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

btrfs: fix root ref counts in error handling in btrfs_get_root_ref

In btrfs_get_root_ref(), when btrfs_insert_fs_root() fails,
btrfs_put_root() can happen for two reasons:

- the root already exists

btrfs: fix root ref counts in error handling in btrfs_get_root_ref

In btrfs_get_root_ref(), when btrfs_insert_fs_root() fails,
btrfs_put_root() can happen for two reasons:

- the root already exists in the tree, in that case it returns the
reference obtained in btrfs_lookup_fs_root()

- another error so the cleanup is done in the fail label

Calling btrfs_put_root() unconditionally would lead to double decrement
of the root reference possibly freeing it in the second case.

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Fixes: bc44d7c4b2b1 ("btrfs: push btrfs_grab_fs_root into btrfs_get_fs_root")
CC: stable@vger.kernel.org # 5.10+
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: Convert from set_page_dirty to dirty_folio

Optimise the non-DEBUG case to just call filemap_dirty_folio
directly. The DEBUG case doesn't actually compile, but convert
it to dirty_folio anywa

btrfs: Convert from set_page_dirty to dirty_folio

Optimise the non-DEBUG case to just call filemap_dirty_folio
directly. The DEBUG case doesn't actually compile, but convert
it to dirty_folio anyway.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs

show more ...

btrfs: Convert from invalidatepage to invalidate_folio

A lot of the underlying infrastructure in btrfs needs to be switched
over to folios, but this at least documents that invalidatepage can't
be p

btrfs: Convert from invalidatepage to invalidate_folio

A lot of the underlying infrastructure in btrfs needs to be switched
over to folios, but this at least documents that invalidatepage can't
be passed a tail page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs

show more ...

btrfs: verify the tranisd of the to-be-written dirty extent buffer

[BUG]
There is a bug report that a bitflip in the transid part of an extent
buffer makes btrfs to reject certain tree blocks:

BT

btrfs: verify the tranisd of the to-be-written dirty extent buffer

[BUG]
There is a bug report that a bitflip in the transid part of an extent
buffer makes btrfs to reject certain tree blocks:

BTRFS error (device dm-0): parent transid verify failed on 1382301696 wanted 262166 found 22

[CAUSE]
Note the failed transid check, hex(262166) = 0x40016, while
hex(22) = 0x16.

It's an obvious bitflip.

Furthermore, the reporter also confirmed the bitflip is from the
hardware, so it's a real hardware caused bitflip, and such problem can
not be detected by the existing tree-checker framework.

As tree-checker can only verify the content inside one tree block, while
generation of a tree block can only be verified against its parent.

So such problem remain undetected.

[FIX]
Although tree-checker can not verify it at write-time, we still have a
quick (but not the most accurate) way to catch such obvious corruption.

Function csum_one_extent_buffer() is called before we submit metadata
write.

Thus it means, all the extent buffer passed in should be dirty tree
blocks, and should be newer than last committed transaction.

Using that we can catch the above bitflip.

Although it's not a perfect solution, as if the corrupted generation is
higher than the correct value, we have no way to catch it at all.

Reported-by: Christoph Anton Mitterer <calestyo@scientia.org>
Link: https://lore.kernel.org/linux-btrfs/2dfcbc130c55cc6fd067b93752e90bd2b079baca.camel@scientia.org/
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Qu Wenruo <wqu@sus,ree.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: unify the error handling pattern for read_tree_block()

We had an error handling pattern for read_tree_block() like this:

eb = read_tree_block();
if (IS_ERR(eb)) {
/*
* Handling error

btrfs: unify the error handling pattern for read_tree_block()

We had an error handling pattern for read_tree_block() like this:

eb = read_tree_block();
if (IS_ERR(eb)) {
/*
* Handling error here
* Normally ended up with return or goto out.
*/
} else if (!extent_buffer_uptodate(eb)) {
/*
* Different error handling here
* Normally also ended up with return or goto out;
*/
}

This is fine, but if we want to add extra check for each
read_tree_block(), the existing if-else-if is not that expandable and
will take reader some seconds to figure out there is no extra branch.

Here we change it to a more common way, without the extra else:

eb = read_tree_block();
if (IS_ERR(eb)) {
/*
* Handling error here
*/
return eb or goto out;
}
if (!extent_buffer_uptodate(eb)) {
/*
* Different error handling here
*/
return eb or goto out;
}

This also removes some oddball call sites which uses some creative way
to check error.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: pass btrfs_fs_info to btrfs_recover_relocation

We don't need a root here, we just need the btrfs_fs_info, we can just
get the specific roots we need from fs_info.

Reviewed-by: Filipe Manana

btrfs: pass btrfs_fs_info to btrfs_recover_relocation

We don't need a root here, we just need the btrfs_fs_info, we can just
get the specific roots we need from fs_info.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: pass btrfs_fs_info for deleting snapshots and cleaner

We're passing a root around here, but we only really need the fs_info,
so fix up btrfs_clean_one_deleted_snapshot() to take an fs_info in

btrfs: pass btrfs_fs_info for deleting snapshots and cleaner

We're passing a root around here, but we only really need the fs_info,
so fix up btrfs_clean_one_deleted_snapshot() to take an fs_info instead,
and then fix up all the callers appropriately.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...

btrfs: add support for multiple global roots

With extent tree v2 you will be able to create multiple csum, extent,
and free space trees. They will be used based on the block group, which
will now u

btrfs: add support for multiple global roots

With extent tree v2 you will be able to create multiple csum, extent,
and free space trees. They will be used based on the block group, which
will now use the block_group_item->chunk_objectid to point to the set of
global roots that it will use. When allocating new block groups we'll
simply mod the gigabyte offset of the block group against the number of
global roots we have and that will be the block groups global id.

>From there we can take the bytenr that we're modifying in the respective
tree, look up the block group and get that block groups corresponding
global root id. From there we can get to the appropriate global root
for that bytenr.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: add code to support the block group root

This code adds the on disk structures for the block group root, which
will hold the block group items for extent tree v2.

Signed-off-by: Josef Bacik

btrfs: add code to support the block group root

This code adds the on disk structures for the block group root, which
will hold the block group items for extent tree v2.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

show more ...