From d352ac68148b69937d39ca5d48bcc4478e118dbf Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 29 Sep 2008 15:18:18 -0400 Subject: 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 --- fs/btrfs/root-tree.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/root-tree.c') diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c index 0091c01abb0..eb7f7655e9d 100644 --- a/fs/btrfs/root-tree.c +++ b/fs/btrfs/root-tree.c @@ -22,8 +22,10 @@ #include "print-tree.h" /* - * returns 0 on finding something, 1 if no more roots are there - * and < 0 on error + * search forward for a root, starting with objectid 'search_start' + * if a root key is found, the objectid we find is filled into 'found_objectid' + * and 0 is returned. < 0 is returned on error, 1 if there is nothing + * left in the tree. */ int btrfs_search_root(struct btrfs_root *root, u64 search_start, u64 *found_objectid) @@ -66,6 +68,11 @@ out: return ret; } +/* + * lookup the root with the highest offset for a given objectid. The key we do + * find is copied into 'key'. If we find something return 0, otherwise 1, < 0 + * on error. + */ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct btrfs_root_item *item, struct btrfs_key *key) { @@ -104,6 +111,9 @@ out: return ret; } +/* + * copy the data in 'item' into the btree + */ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_key *key, struct btrfs_root_item *item) @@ -147,6 +157,12 @@ int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root return ret; } +/* + * at mount time we want to find all the old transaction snapshots that were in + * the process of being deleted if we crashed. This is any root item with an offset + * lower than the latest root. They need to be queued for deletion to finish + * what was happening when we crashed. + */ int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid, struct btrfs_root *latest) { @@ -227,6 +243,7 @@ err: return ret; } +/* drop the root item for 'key' from 'root' */ int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_key *key) { -- cgit v1.2.3