When we COW a block we are holding a lock on the original block, and
then we lock the new COW block. Because our lockdep maps are based on
root + level, this will make lockdep complain. We need a way to
indicate a subclass for locking the COW'ed block, so plumb through our
btrfs_lock_nesting from btrfs_cow_block down to the btrfs_init_buffer,
and then introduce BTRFS_NESTING_COW to be used for cow'ing blocks.
The reason I've added all this extra infrastructure is because there
will be need of different nesting classes in follow up patches.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since most metadata reservation calls can return -EINTR when get
interrupted by fatal signal, we need to review the all the metadata
reservation call sites.
In relocation code, the metadata reservation happens in the following
sites:
- btrfs_block_rsv_refill() in merge_reloc_root()
merge_reloc_root() is a pretty critical section, we don't want to be
interrupted by signal, so change the flush status to
BTRFS_RESERVE_FLUSH_LIMIT, so it won't get interrupted by signal.
Since such change can be ENPSPC-prone, also shrink the amount of
metadata to reserve least amount avoid deadly ENOSPC there.
- btrfs_block_rsv_refill() in reserve_metadata_space()
It calls with BTRFS_RESERVE_FLUSH_LIMIT, which won't get interrupted
by signal.
- btrfs_block_rsv_refill() in prepare_to_relocate()
- btrfs_block_rsv_add() in prepare_to_relocate()
- btrfs_block_rsv_refill() in relocate_block_group()
- btrfs_delalloc_reserve_metadata() in relocate_file_extent_cluster()
- btrfs_start_transaction() in relocate_block_group()
- btrfs_start_transaction() in create_reloc_inode()
Can be interrupted by fatal signal and we can handle it easily.
For these call sites, just catch the -EINTR value in btrfs_balance()
and count them as canceled.
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Although btrfs balance can be canceled with "btrfs balance cancel"
command, it's still almost muscle memory to press Ctrl-C to cancel a
long running btrfs balance.
So allow btrfs balance to check signal to determine if it should exit.
The cancellation points are in known location and we're only adding one
more reason, so this should be safe.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The vfs inode is only used for a pair of inode_lock/unlock calls all
other uses call for btrfs_inode.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
No point in taking an inode only to get btrfs_fs_info from it, instead
take btrfs_fs_info directly.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Preparation to make btrfs_dirty_pages take btrfs_inode as parameter.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This function iterates all extents in the extent cluster, make this
intention obvious by using a for loop. No functional chanes.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_alloc_data_chunk_ondemand and btrfs_free_reserved_data_space_noquota
don't really use the guts of the inodes being passed to them. This
implies it's not required to call them under extent lock. Move code
around in prealloc_file_extent_cluster to do the heavy, data alloc/free
operations outside of the lock. This also makes the 'out' label
unnecessary, so remove it.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Extents in the extent cluster are guaranteed to be contiguous as such
the hole check inside the loop can never trigger. In fact this check was
never functional since it was added in 18513091af ("btrfs: update
btrfs_space_info's bytes_may_use timely") which came after the commit
introducing clustered/contiguous extents 0257bb82d2 ("Btrfs: relocate
file extents in clusters").
Let's just remove it as it adds noise to the source.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It really wants btrfs_inode and not a vfs inode.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It doesn't use the generic vfs inode for anything use btrfs_inode
directly.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We currently use btrfs_check_data_free_space() when allocating space for
relocating data extents, but that is not necessary because that function
combines btrfs_alloc_data_chunk_ondemand(), which does the actual space
reservation, and btrfs_qgroup_reserve_data().
We can use btrfs_alloc_data_chunk_ondemand() directly because we know we
do not need to reserve qgroup space since we are dealing with a relocation
tree, which can never have qgroups (btrfs_qgroup_reserve_data() does
nothing as is_fstree() returns false for a relocation tree).
Conversely we can use btrfs_free_reserved_data_space_noquota() directly
instead of btrfs_free_reserved_data_space(), since we had no qgroup
reservation when allocating space.
This change is preparatory work for another patch in this series that
makes relocation reserve the exact amount of space it needs to relocate
a data block group. The function btrfs_check_data_free_space() has
the incovenient of requiring a start offset argument and we will want to
be able to allocate space for multiple ranges, which are not consecutive,
at once.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The inode lookup starting at btrfs_iget takes the full location key,
while only the objectid is used to match the inode, because the lookup
happens inside the given root thus the inode number is unique.
The entire location key is properly set up in btrfs_init_locked_inode.
Simplify the helpers and pass only inode number, renaming it to 'ino'
instead of 'objectid'. This allows to remove temporary variables key,
saving some stack space.
Signed-off-by: David Sterba <dsterba@suse.com>
The main function to lookup a root by its id btrfs_get_fs_root takes the
whole key, while only using the objectid. The value of offset is preset
to (u64)-1 but not actually used until btrfs_find_root that does the
actual search.
Switch btrfs_get_fs_root to use only objectid and remove all local
variables that existed just for the lookup. The actual key for search is
set up in btrfs_get_fs_root, reusing another key variable.
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
There are several reported runaway balance, that balance is flooding the
log with "found X extents" where the X never changes.
[CAUSE]
Commit d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after
merge_reloc_roots") introduced BTRFS_ROOT_DEAD_RELOC_TREE bit to
indicate that one subvolume has finished its tree blocks swap with its
reloc tree.
However if balance is canceled or hits ENOSPC halfway, we didn't clear
the BTRFS_ROOT_DEAD_RELOC_TREE bit, leaving that bit hanging forever
until unmount.
Any subvolume root with that bit, would cause backref cache to skip this
tree block, as it has finished its tree block swap. This would cause
all tree blocks of that root be ignored by balance, leading to runaway
balance.
[FIX]
Fix the problem by also clearing the BTRFS_ROOT_DEAD_RELOC_TREE bit for
the original subvolume of orphan reloc root.
Add an umount check for the stale bit still set.
Fixes: d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
SHAREABLE flag is set for subvolumes because users can create snapshot
for subvolumes, thus sharing tree blocks of them.
But data reloc tree is not exposed to user space, as it's only an
internal tree for data relocation, thus it doesn't need the full path
replacement handling at all.
This patch will make data reloc tree a non-shareable tree, and add
btrfs_fs_info::data_reloc_root for data reloc tree, so relocation code
can grab it from fs_info directly.
This would slightly improve tree relocation, as now data reloc tree
can go through regular COW routine to get relocated, without bothering
the complex tree reloc tree routine.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The name BTRFS_ROOT_REF_COWS is not very clear about the meaning.
In fact, that bit can only be set to those trees:
- Subvolume roots
- Data reloc root
- Reloc roots for above roots
All other trees won't get this bit set. So just by the result, it is
obvious that, roots with this bit set can have tree blocks shared with
other trees. Either shared by snapshots, or by reloc roots (an special
snapshot created by relocation).
This patch will rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE to
make it easier to understand, and update all comment mentioning
"reference counted" to follow the rename.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All callers pass the eb::level so we can get read it directly inside the
btrfs_bin_search and key_search.
This is inspired by the work of Marek in U-boot.
CC: Marek Behun <marek.behun@nic.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The function always works on a local copy of the reloc root list, which
cannot be modified outside of it so using list_for_each_entry is fine.
Additionally the macro handles empty lists so drop list_empty checks of
callers. No semantic changes.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The error cleanup will be extracted as a new function,
btrfs_backref_error_cleanup(), and moved to backref.c and exported for
later usage.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This the the 2nd major part of generic backref cache. Move it to
backref.c so we can reuse it.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This function is the major part of backref cache build process, move it
to backref.c so we can reuse it later.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The backref code is going to be moved to backref.c, and read_fs_root()
is just a simple wrapper, open-code it to prepare to the incoming code
move.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This function is mostly single purpose to relocation backref cache, but
since we're moving the main part of backref cache to backref.c, we need
to export such function.
And to avoid confusion, rename the function to
btrfs_should_ignore_reloc_root() make the name a little more clear.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Also change the parameter, since all callers can easily grab an fs_info,
there is no need for all the pointer chasing.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we're releasing all existing nodes/edges, other than cleanup the
mess after error, "release" is a more proper naming here.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Also add comment explaining the cleanup progress, to differ it from
btrfs_backref_drop_node().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With extra comment for drop_backref_node() as it has some similarity
with remove_backref_node(), thus we need extra comment explaining the
difference.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Structure tree_entry provides a very simple rb_tree which only uses
bytenr as search index.
That tree_entry is used in 3 structures: backref_node, mapping_node and
tree_block.
Since we're going to make backref_node independnt from relocation, it's
a good time to extract the tree_entry into rb_simple_node, and export it
into misc.h.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These 3 structures are the main part of btrfs backref cache, move them
to backref.h to build the basis for later reuse.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Those three structures are the main elements of backref cache. Add the
"btrfs_" prefix for later export.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This patch will also add some comment for the cleanup.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
After handle_one_tree_backref(), all newly added (not cached) edges and
nodes have the following features:
- Only backref_edge::list[LOWER] is linked.
This means, we can only iterate from botton to top, not the other
direction.
- Newly added nodes are not added to cache rb_tree yet
So to finish the backref cache, we still need to finish the links and
add all nodes into backref cache rb_tree.
This patch will refactor the existing code into finish_upper_links(),
add more comments of each branch, and why we need to do all the work.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
build_backref_tree() uses "goto again;" to implement a breadth-first
search to build backref cache.
This patch will extract most of its work into a wrapper,
handle_one_tree_block(), and use a do {} while() loop to implement the
same thing.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Bytenr and level are essential parameters for backref_node, thus it
makes sense to initialize them at allocation time.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since backref_edge is used to connect upper and lower backref nodes, and
needs to access both nodes, some code can look pretty nasty:
list_add_tail(&edge->list[LOWER], &cur->upper);
The above code will link @cur to the LOWER side of the edge, while both
"LOWER" and "upper" words show up. This can sometimes be very confusing
for reader to grasp.
This patch introduces a new wrapper, link_backref_edge(), to handle the
linking behavior. Which also has extra ASSERT() to ensure caller won't
pass wrong nodes.
Also, this updates the comment of related lists of backref_node and
backref_edge, to make it more clear that each list points to what.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The processing of indirect tree backref (TREE_BLOCK_REF) is the most
complex work.
We need to grab the fs root, do a tree search to locate all its parent
nodes, link all needed edges, and put all uncached edges to pending edge
list.
This is definitely worth a helper function.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For BTRFS_SHARED_BLOCK_REF_KEY, its processing is straightforward, as we
now the parent node bytenr directly.
If the parent is already cached, or a root, call it a day.
If the parent is not cached, add it pending list.
This patch will just refactor this part into its own function,
handle_direct_tree_backref() and add some comment explaining the
@ref_key parameter.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
find_reloc_root() searches reloc_control::reloc_root_tree to find the
reloc root. This behavior is only useful for relocation backref cache.
For the incoming more generic purpose backref cache, we don't care
about who owns the reloc root, but only care if it's a reloc root.
So this patch makes the following modifications to make the reloc root
search more specific to relocation backref:
- Add backref_node::is_reloc_root
This will be an extra indicator for generic purposed backref cache.
User doesn't need to read root key from backref_node::root to
determine if it's a reloc root.
Also for reloc tree root, it's useless and will be queued to useless
list.
- Add backref_cache::is_reloc
This will allow backref cache code to do different behavior for
generic purpose backref cache and relocation backref cache.
- Pass fs_info to find_reloc_root()
- Export find_reloc_root()
So backref.c can utilize this function.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add this member so that we can grab fs_info without the help from
reloc_control.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These two new members will act the same as the existing local lists,
@useless and @list in build_backref_tree().
Currently build_backref_tree() is only executed serially, thus moving
such local list into backref_cache is still safe.
Also since we're here, use list_first_entry() to replace a lot of
list_entry() calls after !list_empty().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These two functions are weirdly named, mark_block_processed() in fact
just marks a range dirty unconditionally, while __mark_block_processed()
does extra check before doing the marking.
This patch will open code old mark_block_processed, and rename
__mark_block_processed() to remove the "__" prefix.
Since we're here, also kill the forward declaration, which could also
kill in_block_group() with in_range() macro.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In the core function of relocation, build_backref_tree, it needs to
iterate all backref items of one tree block.
Use btrfs_backref_iter infrastructure to do the loop and make the code
more readable.
The backref items look would be much more easier to read:
ret = btrfs_backref_iter_start(iter, cur->bytenr);
for (; ret == 0; ret = btrfs_backref_iter_next(iter)) {
/* The really important work */
}
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Josef Bacik