linux.git/fs/btrfs/relocation.c, branch v5.9

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

btrfs: make btrfs_reloc_clone_csums take btrfs_inode

2020-07-27T10:55:26+00:00

It really wants btrfs_inode and not a vfs inode.

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

btrfs: make btrfs_lookup_ordered_extent take btrfs_inode

2020-07-27T10:55:25+00:00

It doesn't use the generic vfs inode for anything use btrfs_inode
directly.

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