linux.git/fs/btrfs/relocation.c, branch v5.10

btrfs: fix min reserved size calculation in merge_reloc_root

2020-11-05T12:02:07+00:00

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 
Fixes: 44d354abf33e ("btrfs: relocation: review the call sites which can be interrupted by signal")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Nikolay Borisov 
Tested-by: Nikolay Borisov 
Signed-off-by: Josef Bacik 
Signed-off-by: David Sterba

btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks

2020-10-07T10:12:16+00:00

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 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: relocation: review the call sites which can be interrupted by signal

2020-07-27T10:55:45+00:00

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 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: relocation: allow signal to cancel balance

2020-07-27T10:55:44+00:00

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 
Signed-off-by: Qu Wenruo 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: make prealloc_file_extent_cluster take btrfs_inode

2020-07-27T10:55:37+00:00

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 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: make btrfs_free_reserved_data_space_noquota take btrfs_fs_info

2020-07-27T10:55:35+00:00

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 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: make btrfs_set_extent_delalloc take btrfs_inode

2020-07-27T10:55:35+00:00

Preparation to make btrfs_dirty_pages take btrfs_inode as parameter.

Signed-off-by: Nikolay Borisov 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: use for loop in prealloc_file_extent_cluster

2020-07-27T10:55:27+00:00

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 
Signed-off-by: Nikolay Borisov 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: perform data management operations outside of inode lock

2020-07-27T10:55:27+00:00

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 
Signed-off-by: Nikolay Borisov 
Signed-off-by: David Sterba

btrfs: remove hole check in prealloc_file_extent_cluster

2020-07-27T10:55:27+00:00

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 18513091af94 ("btrfs: update
btrfs_space_info's bytes_may_use timely") which came after the commit
introducing clustered/contiguous extents 0257bb82d21b ("Btrfs: relocate
file extents in clusters").

Let's just remove it as it adds noise to the source.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: Nikolay Borisov 
Signed-off-by: David Sterba