Btrfs: add and improve comments

This improves the comments at the top of many functions.  It didn't
dive into the guts of functions because I was trying to
avoid merging problems with the new allocator and back reference work.

extent-tree.c and volumes.c were both skipped, and there is definitely
more work todo in cleaning and commenting the code.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2008-09-29 15:18:18 -04:00
parent 9a5e1ea1e1
commit d352ac6814
25 changed files with 653 additions and 277 deletions

View File

@@ -21,6 +21,16 @@
#include "ref-cache.h"
#include "transaction.h"
/*
* leaf refs are used to cache the information about which extents
* a given leaf has references on. This allows us to process that leaf
* in btrfs_drop_snapshot without needing to read it back from disk.
*/
/*
* kmalloc a leaf reference struct and update the counters for the
* total ref cache size
*/
struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(struct btrfs_root *root,
int nr_extents)
{
@@ -40,6 +50,10 @@ struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(struct btrfs_root *root,
return ref;
}
/*
* free a leaf reference struct and update the counters for the
* total ref cache size
*/
void btrfs_free_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
{
if (!ref)
@@ -135,6 +149,10 @@ int btrfs_remove_leaf_refs(struct btrfs_root *root, u64 max_root_gen,
return 0;
}
/*
* find the leaf ref for a given extent. This returns the ref struct with
* a usage reference incremented
*/
struct btrfs_leaf_ref *btrfs_lookup_leaf_ref(struct btrfs_root *root,
u64 bytenr)
{
@@ -160,6 +178,10 @@ again:
return NULL;
}
/*
* add a fully filled in leaf ref struct
* remove all the refs older than a given root generation
*/
int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref,
int shared)
{
@@ -184,6 +206,10 @@ int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref,
return ret;
}
/*
* remove a single leaf ref from the tree. This drops the ref held by the tree
* only
*/
int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
{
struct btrfs_leaf_ref_tree *tree;