Current delayed ref interface has several problems:
- Longer and longer parameter lists
bytenr
num_bytes
parent
---- So far so good
ref_root
owner
offset
---- I don't feel well now
for_reloc
^^^^ This parameter only makes sense for qgroup code, but we need
to pass the parameter a long way.
This makes later expand on parameter list more and more tricky.
- Different interpretation for the same parameter
Above @owner for data ref is ino who owns this extent,
while for tree ref, it's level. They are even in different size range.
For level we only need 0~8, while for ino it's
BTRFS_FIRST_FREE_OBJECTID~BTRFS_LAST_FREE_OBJECTID, so it's still
possible to distinguish them, but it's never a straight-forward thing
to grasp.
And @offset doesn't even makes sense for tree ref.
Such parameter reuse may look clever as an hidden union, but it
destroys code readability.
This patchset will change the way how we pass parameters for delayed
ref.
Instead of calling delayed ref interface like:
ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, parent,
ref_root, owner, offset);
Or
ret = btrfs_inc_extent_ref(trans, root, bytenr, nodesize, parent,
level, ref_root, 0);
We now call like:
btrfs_init_generic_ref(&ref, bytenr, num_bytes,
root->root_key.objectid, parent);
btrfs_init_data_ref(&ref, ref_root, owner, offset);
ret = btrfs_inc_extent_ref(trans, &ref);
Or
btrfs_init_generic_ref(&ref, bytenr, num_bytes,
root->root_key.objectid, parent);
btrfs_init_tree_ref(&ref, level, ref_root);
ret = btrfs_inc_extent_ref(trans, &ref);
To determine if a ref is tree or data, instead of calling like:
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
} else {
}
We do it straight-forward:
if (ref->type == BTRFS_REF_METADATA) {
} else {
}
And for newer and minor new members, we don't need to add a new
parameter to btrfs_add_delayed_tree|data_ref() or
btrfs_inc_extent_ref(), just assign them after generic/data/tree init:
btrfs_init_generic_ref(&ref, bytenr, num_bytes,
root->root_key.objectid, parent);
btrfs_init_data_ref(&ref, ref_root, owner, offset);
ref->skip_qgroup = true; /* @skip_qgroup is default to false, so new
code doesn't need to care */
ret = btrfs_inc_extent_ref(trans, &ref);
This should improve the code readability and make later code easier to
write.
Qu Wenruo (8):
btrfs: delayed-ref: Introduce better documented delayed ref structures
btrfs: extent-tree: Open-code process_func in __btrfs_mod_ref
btrfs: delayed-ref: Use btrfs_ref to refactor
btrfs_add_delayed_tree_ref()
btrfs: delayed-ref: Use btrfs_ref to refactor
btrfs_add_delayed_data_ref()
btrfs: ref-verify: Use btrfs_ref to refactor btrfs_ref_tree_mod()
btrfs: extent-tree: Use btrfs_ref to refactor add_pinned_bytes()
btrfs: extent-tree: Use btrfs_ref to refactor btrfs_inc_extent_ref()
btrfs: extent-tree: Use btrfs_ref to refactor btrfs_free_extent()
fs/btrfs/ctree.h | 11 +--
fs/btrfs/delayed-ref.c | 43 ++++++---
fs/btrfs/delayed-ref.h | 121 +++++++++++++++++++++++--
fs/btrfs/extent-tree.c | 195 +++++++++++++++++++----------------------
fs/btrfs/file.c | 43 +++++----
fs/btrfs/inode.c | 23 +++--
fs/btrfs/ioctl.c | 17 ++--
fs/btrfs/ref-verify.c | 53 ++++++-----
fs/btrfs/ref-verify.h | 10 +--
fs/btrfs/relocation.c | 70 +++++++++------
fs/btrfs/tree-log.c | 12 ++-
11 files changed, 375 insertions(+), 223 deletions(-)
--
2.19.2
