Commit Graph

387 Commits

Author SHA1 Message Date
Nikolay Borisov 5297199a8b btrfs: remove inode number cache feature
It's been deprecated since commit b547a88ea5 ("btrfs: start
deprecation of mount option inode_cache") which enumerates the reasons.

A filesystem that uses the feature (mount -o inode_cache) tracks the
inode numbers in bitmaps, that data stay on the filesystem after this
patch. The size is roughly 5MiB for 1M inodes [1], which is considered
small enough to be left there. Removal of the change can be implemented
in btrfs-progs if needed.

[1] https://lore.kernel.org/linux-btrfs/20201127145836.GZ6430@twin.jikos.cz/

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09 19:16:05 +01:00
Nikolay Borisov 8df01fddb7 btrfs: remove err variable from do_relocation
It simply gets assigned to 'ret' in case of errors. The flow of the
while loop is not changed by this commit since the few call sites
that 'goto next' will simply break from the loop.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:54:15 +01:00
Nikolay Borisov c6a592f2e2 btrfs: eliminate err variable from merge_reloc_root
In most cases when an error is returned from a function 'ret' is simply
assigned to 'err'. There is only one case where walk_up_reloc_tree can
return a positive value - in this case the code breaks from the loop and
ret is going to get its return value from btrfs_cow_block - either 0 or
negative. This retains the old logic of how 'err' used to be set at
this call site.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:54:15 +01:00
Josef Bacik 3fbaf25817 btrfs: pass the owner_root and level to alloc_extent_buffer
Now that we've plumbed all of the callers to have the owner root and the
level, plumb it down into alloc_extent_buffer().

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>
2020-12-08 15:54:07 +01:00
Josef Bacik 1b7ec85ef4 btrfs: pass root owner to read_tree_block
In order to properly set the lockdep class of a newly allocated block we
need to know the owner of the block.  For non-refcounted trees this is
straightforward, we always know in advance what tree we're reading from.
For refcounted trees we don't necessarily know, however all refcounted
trees share the same lockdep class name, tree-<level>.

Fix all the callers of read_tree_block() to pass in the root objectid
we're using.  In places like relocation and backref we could probably
unconditionally use 0, but just in case use the root when we have it,
otherwise use 0 in the cases we don't have the root as it's going to be
a refcounted tree anyway.

This is a preparation patch for further changes.

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>
2020-12-08 15:54:07 +01:00
Josef Bacik 6b3426be27 btrfs: use btrfs_read_node_slot in replace_path
We're open-coding btrfs_read_node_slot() here, replace with the helper.

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>
2020-12-08 15:54:06 +01:00
Josef Bacik c975253682 btrfs: use btrfs_read_node_slot in do_relocation
We're open coding btrfs_read_node_slot in do_relocation, replace this
with the proper helper.

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>
2020-12-08 15:54:06 +01:00
Josef Bacik 8ef385bbf0 btrfs: use btrfs_read_node_slot in walk_down_reloc_tree
We do not need to call read_tree_block() here, simply use the
btrfs_read_node_slot helper.

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>
2020-12-08 15:54:06 +01:00
Josef Bacik bfb484d922 btrfs: cleanup extent buffer readahead
We're going to pass around more information when we allocate extent
buffers, in order to make that cleaner how we do readahead.  Most of the
callers have the parent node that we're getting our blockptr from, with
the sole exception of relocation which simply has the bytenr it wants to
read.

Add a helper that takes the current arguments that we need (bytenr and
gen), and add another helper for simply reading the slot out of a node.
In followup patches the helper that takes all the extra arguments will
be expanded, and the simpler helper won't need to have it's arguments
adjusted.

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>
2020-12-08 15:54:05 +01:00
Josef Bacik ac5887c8e0 btrfs: locking: remove all the blocking helpers
Now that we're using a rw_semaphore we no longer need to indicate if a
lock is blocking or not, nor do we need to flip the entire path from
blocking to spinning.  Remove these helpers and all the places they are
called.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:54:01 +01:00
David Sterba c842268458 btrfs: add set/get accessors for root_item::drop_level
The drop_level member is used directly unlike all the other int types in
root_item. Add the definition and use it everywhere. The type is u8 so
there's no conversion necessary and the helpers are properly inlined,
this is for consistency.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08 15:53:52 +01:00
Josef Bacik fca3a45d08 btrfs: fix min reserved size calculation in merge_reloc_root
The minimum reserve size was adjusted to take into account the height of
the tree we are merging, however we can have a root with a level == 0.
What we want is root_level + 1 to get the number of nodes we may have to
cow.  This fixes the enospc_debug warning pops with btrfs/101.

Nikolay: this fixes failures on btrfs/060 btrfs/062 btrfs/063 and
btrfs/195 That I was seeing, the call trace was:

  [ 3680.515564] ------------[ cut here ]------------
  [ 3680.515566] BTRFS: block rsv returned -28
  [ 3680.515585] WARNING: CPU: 2 PID: 8339 at fs/btrfs/block-rsv.c:521 btrfs_use_block_rsv+0x162/0x180
  [ 3680.515587] Modules linked in:
  [ 3680.515591] CPU: 2 PID: 8339 Comm: btrfs Tainted: G        W         5.9.0-rc8-default #95
  [ 3680.515593] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014
  [ 3680.515595] RIP: 0010:btrfs_use_block_rsv+0x162/0x180
  [ 3680.515600] RSP: 0018:ffffa01ac9753910 EFLAGS: 00010282
  [ 3680.515602] RAX: 0000000000000000 RBX: ffff984b34200000 RCX: 0000000000000027
  [ 3680.515604] RDX: 0000000000000027 RSI: 0000000000000000 RDI: ffff984b3bd19e28
  [ 3680.515606] RBP: 0000000000004000 R08: ffff984b3bd19e20 R09: 0000000000000001
  [ 3680.515608] R10: 0000000000000004 R11: 0000000000000046 R12: ffff984b264fdc00
  [ 3680.515609] R13: ffff984b13149000 R14: 00000000ffffffe4 R15: ffff984b34200000
  [ 3680.515613] FS:  00007f4e2912b8c0(0000) GS:ffff984b3bd00000(0000) knlGS:0000000000000000
  [ 3680.515615] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [ 3680.515617] CR2: 00007fab87122150 CR3: 0000000118e42000 CR4: 00000000000006e0
  [ 3680.515620] Call Trace:
  [ 3680.515627]  btrfs_alloc_tree_block+0x8b/0x340
  [ 3680.515633]  ? __lock_acquire+0x51a/0xac0
  [ 3680.515646]  alloc_tree_block_no_bg_flush+0x4f/0x60
  [ 3680.515651]  __btrfs_cow_block+0x14e/0x7e0
  [ 3680.515662]  btrfs_cow_block+0x144/0x2c0
  [ 3680.515670]  merge_reloc_root+0x4d4/0x610
  [ 3680.515675]  ? btrfs_lookup_fs_root+0x78/0x90
  [ 3680.515686]  merge_reloc_roots+0xee/0x280
  [ 3680.515695]  relocate_block_group+0x2ce/0x5e0
  [ 3680.515704]  btrfs_relocate_block_group+0x16e/0x310
  [ 3680.515711]  btrfs_relocate_chunk+0x38/0xf0
  [ 3680.515716]  btrfs_shrink_device+0x200/0x560
  [ 3680.515728]  btrfs_rm_device+0x1ae/0x6a6
  [ 3680.515744]  ? _copy_from_user+0x6e/0xb0
  [ 3680.515750]  btrfs_ioctl+0x1afe/0x28c0
  [ 3680.515755]  ? find_held_lock+0x2b/0x80
  [ 3680.515760]  ? do_user_addr_fault+0x1f8/0x418
  [ 3680.515773]  ? __x64_sys_ioctl+0x77/0xb0
  [ 3680.515775]  __x64_sys_ioctl+0x77/0xb0
  [ 3680.515781]  do_syscall_64+0x31/0x70
  [ 3680.515785]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported-by: Nikolay Borisov <nborisov@suse.com>
Fixes: 44d354abf3 ("btrfs: relocation: review the call sites which can be interrupted by signal")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-05 13:02:07 +01:00
Josef Bacik 9631e4cc1a btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks
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>
2020-10-07 12:12:16 +02:00
Qu Wenruo 44d354abf3 btrfs: relocation: review the call sites which can be interrupted by signal
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>
2020-07-27 12:55:45 +02:00
Qu Wenruo 5cb502f4ab btrfs: relocation: allow signal to cancel balance
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>
2020-07-27 12:55:44 +02:00
Nikolay Borisov 056d9beca3 btrfs: make prealloc_file_extent_cluster take btrfs_inode
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>
2020-07-27 12:55:37 +02:00
Nikolay Borisov 9db5d510ac btrfs: make btrfs_free_reserved_data_space_noquota take btrfs_fs_info
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>
2020-07-27 12:55:35 +02:00
Nikolay Borisov c2566f2289 btrfs: make btrfs_set_extent_delalloc take btrfs_inode
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>
2020-07-27 12:55:35 +02:00
Nikolay Borisov 4e9d0d0109 btrfs: use for loop in prealloc_file_extent_cluster
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>
2020-07-27 12:55:27 +02:00
Nikolay Borisov 214e61d07e btrfs: perform data management operations outside of inode lock
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>
2020-07-27 12:55:27 +02:00
Nikolay Borisov c171edd5c8 btrfs: remove hole check in prealloc_file_extent_cluster
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>
2020-07-27 12:55:27 +02:00
Nikolay Borisov 7bfa953501 btrfs: make btrfs_reloc_clone_csums take btrfs_inode
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>
2020-07-27 12:55:26 +02:00
Nikolay Borisov c350437269 btrfs: make btrfs_lookup_ordered_extent take btrfs_inode
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>
2020-07-27 12:55:25 +02:00
Filipe Manana a89ef455dd btrfs: use btrfs_alloc_data_chunk_ondemand() when allocating space for relocation
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>
2020-07-27 12:55:21 +02:00
David Sterba 0202e83fda btrfs: simplify iget helpers
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>
2020-05-25 11:25:37 +02:00
David Sterba a820feb546 btrfs: open code read_fs_root
After the update to btrfs_get_fs_root, read_fs_root has become trivial
wrapper that can be open coded.

Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25 11:25:36 +02:00
David Sterba 56e9357a1e btrfs: simplify root lookup by id
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>
2020-05-25 11:25:36 +02:00
Qu Wenruo 1dae7e0e58 btrfs: reloc: clear DEAD_RELOC_TREE bit for orphan roots to prevent runaway balance
[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>
2020-05-25 11:25:36 +02:00
Qu Wenruo 51415b6c1b btrfs: reloc: fix reloc root leak and NULL pointer dereference
[BUG]
When balance is canceled, there is a pretty high chance that unmounting
the fs can lead to lead the NULL pointer dereference:

  BTRFS warning (device dm-3): page private not zero on page 223158272
  ...
  BTRFS warning (device dm-3): page private not zero on page 223162368
  BTRFS error (device dm-3): leaked root 18446744073709551608-304 refcount 1
  BUG: kernel NULL pointer dereference, address: 0000000000000168
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] PREEMPT SMP NOPTI
  CPU: 2 PID: 5793 Comm: umount Tainted: G           O      5.7.0-rc5-custom+ #53
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:__lock_acquire+0x5dc/0x24c0
  Call Trace:
   lock_acquire+0xab/0x390
   _raw_spin_lock+0x39/0x80
   btrfs_release_extent_buffer_pages+0xd7/0x200 [btrfs]
   release_extent_buffer+0xb2/0x170 [btrfs]
   free_extent_buffer+0x66/0xb0 [btrfs]
   btrfs_put_root+0x8e/0x130 [btrfs]
   btrfs_check_leaked_roots.cold+0x5/0x5d [btrfs]
   btrfs_free_fs_info+0xe5/0x120 [btrfs]
   btrfs_kill_super+0x1f/0x30 [btrfs]
   deactivate_locked_super+0x3b/0x80
   deactivate_super+0x3e/0x50
   cleanup_mnt+0x109/0x160
   __cleanup_mnt+0x12/0x20
   task_work_run+0x67/0xa0
   exit_to_usermode_loop+0xc5/0xd0
   syscall_return_slowpath+0x205/0x360
   do_syscall_64+0x6e/0xb0
   entry_SYSCALL_64_after_hwframe+0x49/0xb3
  RIP: 0033:0x7fd028ef740b

[CAUSE]
When balance is canceled, all reloc roots are marked as orphan, and
orphan reloc roots are going to be cleaned up.

However for orphan reloc roots and merged reloc roots, their lifespan
are quite different:

	Merged reloc roots	|	Orphan reloc roots by cancel
--------------------------------------------------------------------
create_reloc_root()		| create_reloc_root()
|- refs == 1			| |- refs == 1
				|
btrfs_grab_root(reloc_root);	| btrfs_grab_root(reloc_root);
|- refs == 2			| |- refs == 2
				|
root->reloc_root = reloc_root;	| root->reloc_root = reloc_root;
		>>> No difference so far <<<
				|
prepare_to_merge()		| prepare_to_merge()
|- btrfs_set_root_refs(item, 1);| |- if (!err) (err == -EINTR)
				|
merge_reloc_roots()		| merge_reloc_roots()
|- merge_reloc_root()		| |- Doing nothing to put reloc root
   |- insert_dirty_subvol()	| |- refs == 2
      |- __del_reloc_root()	|
         |- btrfs_put_root()	|
            |- refs == 1	|
		>>> Now orphan reloc roots still have refs 2 <<<
				|
clean_dirty_subvols()		| clean_dirty_subvols()
|- btrfs_drop_snapshot()	| |- btrfS_drop_snapshot()
   |- reloc_root get freed	|    |- reloc_root still has refs 2
				|	related ebs get freed, but
				|	reloc_root still recorded in
				|	allocated_roots
btrfs_check_leaked_roots()	| btrfs_check_leaked_roots()
|- No leaked roots		| |- Leaked reloc_roots detected
				| |- btrfs_put_root()
				|    |- free_extent_buffer(root->node);
				|       |- eb already freed, caused NULL
				|	   pointer dereference

[FIX]
The fix is to clear fs_root->reloc_root and put it at
merge_reloc_roots() time, so that we won't leak reloc roots.

Fixes: d2311e6985 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots")
CC: stable@vger.kernel.org # 5.1+
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25 11:25:36 +02:00
Qu Wenruo aeb935a455 btrfs: don't set SHAREABLE flag for data reloc tree
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>
2020-05-25 11:25:35 +02:00
Qu Wenruo 92a7cc4252 btrfs: rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE
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>
2020-05-25 11:25:35 +02:00
Qu Wenruo e3b8336117 btrfs: remove the redundant parameter level in btrfs_bin_search()
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>
2020-05-25 11:25:24 +02:00
Nikolay Borisov a7571232b2 btrfs: use list_for_each_entry_safe in free_reloc_roots
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>
2020-05-25 11:25:23 +02:00
Qu Wenruo 1b23ea180b btrfs: reloc: move error handling of build_backref_tree() to backref.c
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>
2020-05-25 11:25:21 +02:00
Qu Wenruo fc997ed05a btrfs: backref: rename and move finish_upper_links()
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>
2020-05-25 11:25:21 +02:00
Qu Wenruo 1b60d2ec98 btrfs: backref: rename and move handle_one_tree_block()
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>
2020-05-25 11:25:21 +02:00
Qu Wenruo d36e7f0e8f btrfs: reloc: open code read_fs_root() for handle_indirect_tree_backref()
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>
2020-05-25 11:25:21 +02:00
Qu Wenruo 55465730bc btrfs: backref: rename and move should_ignore_root()
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>
2020-05-25 11:25:21 +02:00
Qu Wenruo 982c92cbd5 btrfs: backref: rename and move backref_tree_panic()
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>
2020-05-25 11:25:21 +02:00
Qu Wenruo 13fe1bdb22 btrfs: backref: rename and move backref_cache_cleanup()
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>
2020-05-25 11:25:20 +02:00
Qu Wenruo 023acb07bc btrfs: backref: rename and move remove_backref_node()
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>
2020-05-25 11:25:20 +02:00
Qu Wenruo b0fe7078d6 btrfs: backref: rename and move drop_backref_node()
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>
2020-05-25 11:25:20 +02:00
Qu Wenruo 741188d3a5 btrfs: backref: rename and move free_backref_(node|edge)
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25 11:25:20 +02:00
Qu Wenruo f39911e552 btrfs: backref: rename and move link_backref_edge()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25 11:25:20 +02:00
Qu Wenruo 47254d07f3 btrfs: backref: rename and move alloc_backref_edge()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25 11:25:19 +02:00
Qu Wenruo b1818dab9b btrfs: backref: rename and move alloc_backref_node()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25 11:25:19 +02:00
Qu Wenruo 584fb12187 btrfs: backref: rename and move backref_cache_init()
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-25 11:25:19 +02:00
Qu Wenruo e9a28dc52a btrfs: rename tree_entry to rb_simple_node and export it
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>
2020-05-25 11:25:19 +02:00
Qu Wenruo 7053544146 btrfs: backref: move btrfs_backref_(node|edge|cache) structures to backref.h
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>
2020-05-25 11:25:19 +02:00
Qu Wenruo a26195a523 btrfs: reloc: add btrfs_ prefix for backref_node/edge/cache
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>
2020-05-25 11:25:18 +02:00