linux.git/fs/btrfs/ordered-data.c, branch v5.11

btrfs: remove btrfs_find_ordered_sum call from btrfs_lookup_bio_sums

2020-12-09T18:16:10+00:00

The function btrfs_lookup_bio_sums() is only called for read bios.
While btrfs_find_ordered_sum() is to search ordered extent sums, which
is only for write path.

This means to read a page we either:

- Submit read bio if it's not uptodate
  This means we only need to search csum tree for checksums.

- The page is already uptodate
  It can be marked uptodate for previous read, or being marked dirty.
  As we always mark page uptodate for dirty page.
  In that case, we don't need to submit read bio at all, thus no need
  to search any checksums.

Remove the btrfs_find_ordered_sum() call in btrfs_lookup_bio_sums().
And since btrfs_lookup_bio_sums() is the only caller for
btrfs_find_ordered_sum(), also remove the implementation.

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

btrfs: switch cached fs_info::csum_size from u16 to u32

2020-12-08T14:53:59+00:00

The fs_info value is 32bit, switch also the local u16 variables. This
leads to a better assembly code generated due to movzwl.

This simple change will shave some bytes on x86_64 and release config:

   text    data     bss     dec     hex filename
1090000   17980   14912 1122892  11224c pre/btrfs.ko
1089794   17980   14912 1122686  11217e post/btrfs.ko

DELTA: -206

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

btrfs: use cached value of fs_info::csum_size everywhere

2020-12-08T14:53:59+00:00

btrfs_get_16 shows up in the system performance profiles (helper to read
16bit values from on-disk structures). This is partially because of the
checksum size that's frequently read along with data reads/writes, other
u16 uses are from item size or directory entries.

Replace all calls to btrfs_super_csum_size by the cached value from
fs_info.

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

btrfs: replace s_blocksize_bits with fs_info::sectorsize_bits

2020-12-08T14:53:58+00:00

The value of super_block::s_blocksize_bits is the same as
fs_info::sectorsize_bits, but we don't need to do the extra dereferences
in many functions and storing the bits as u32 (in fs_info) generates
shorter assembly.

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

btrfs: use precalculated sectorsize_bits from fs_info

2020-12-08T14:53:57+00:00

We do a lot of calculations where we divide or multiply by sectorsize.
We also know and make sure that sectorsize is a power of two, so this
means all divisions can be turned to shifts and avoid eg. expensive
u64/u32 divisions.

The type is u32 as it's more register friendly on x86_64 compared to u8
and the resulting assembly is smaller (movzbl vs movl).

There's also superblock s_blocksize_bits but it's usually one more
pointer dereference farther than fs_info.

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

btrfs: remove inode argument from btrfs_start_ordered_extent

2020-10-07T10:13:22+00:00

The passed in ordered_extent struct is always well-formed and contains
the inode making the explicit argument redundant.

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

btrfs: switch btrfs_remove_ordered_extent to btrfs_inode

2020-10-07T10:13:21+00:00

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

btrfs: make btrfs_find_ordered_sum take btrfs_inode

2020-10-07T10:12:19+00:00

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

btrfs: convert btrfs_inode_sectorsize to take btrfs_inode

2020-10-07T10:12:18+00:00

It's counterintuitive to have a function named btrfs_inode_xxx which
takes a generic inode. Also move the function to btrfs_inode.h so that
it has access to the definition of struct btrfs_inode.

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

btrfs: make btrfs_dec_test_ordered_pending take btrfs_inode

2020-10-07T10:12:18+00:00

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