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>

1 files changed, 0 insertions, 130 deletions

diff --git a/fs/btrfs/bit-radix.c b/fs/btrfs/bit-radix.c
deleted file mode 100644
index e8bf876db393..000000000000
--- a/fs/btrfs/bit-radix.c
+++ /dev/null
@@ -1,130 +0,0 @@
-/*
- * Copyright (C) 2007 Oracle.  All rights reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License v2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 021110-1307, USA.
- */
-
-#include "bit-radix.h"
-
-#define BIT_ARRAY_BYTES 256
-#define BIT_RADIX_BITS_PER_ARRAY ((BIT_ARRAY_BYTES - sizeof(unsigned long)) * 8)
-
-extern struct kmem_cache *btrfs_bit_radix_cachep;
-int set_radix_bit(struct radix_tree_root *radix, unsigned long bit)
-{
-        unsigned long *bits;
-        unsigned long slot;
-        int bit_slot;
-        int ret;
-
-        slot = bit / BIT_RADIX_BITS_PER_ARRAY;
-        bit_slot = bit % BIT_RADIX_BITS_PER_ARRAY;
-
-        bits = radix_tree_lookup(radix, slot);
-        if (!bits) {
-                bits = kmem_cache_alloc(btrfs_bit_radix_cachep, GFP_NOFS);
-                if (!bits)
-                        return -ENOMEM;
-                memset(bits + 1, 0, BIT_ARRAY_BYTES - sizeof(unsigned long));
-                bits[0] = slot;
-                ret = radix_tree_insert(radix, slot, bits);
-                if (ret)
-                        return ret;
-        }
-        ret = test_and_set_bit(bit_slot, bits + 1);
-        if (ret < 0)
-                ret = 1;
-        return ret;
-}
-
-int test_radix_bit(struct radix_tree_root *radix, unsigned long bit)
-{
-        unsigned long *bits;
-        unsigned long slot;
-        int bit_slot;
-
-        slot = bit / BIT_RADIX_BITS_PER_ARRAY;
-        bit_slot = bit % BIT_RADIX_BITS_PER_ARRAY;
-
-        bits = radix_tree_lookup(radix, slot);
-        if (!bits)
-                return 0;
-        return test_bit(bit_slot, bits + 1);
-}
-
-int clear_radix_bit(struct radix_tree_root *radix, unsigned long bit)
-{
-        unsigned long *bits;
-        unsigned long slot;
-        int bit_slot;
-        int i;
-        int empty = 1;
-
-        slot = bit / BIT_RADIX_BITS_PER_ARRAY;
-        bit_slot = bit % BIT_RADIX_BITS_PER_ARRAY;
-
-        bits = radix_tree_lookup(radix, slot);
-        if (!bits)
-                return 0;
-        clear_bit(bit_slot, bits + 1);
-        for (i = 1; i < BIT_ARRAY_BYTES / sizeof(unsigned long); i++) {
-                if (bits[i]) {
-                        empty = 0;
-                        break;
-                }
-        }
-        if (empty) {
-                bits = radix_tree_delete(radix, slot);
-                BUG_ON(!bits);
-                kmem_cache_free(btrfs_bit_radix_cachep, bits);
-        }
-        return 0;
-}
-
-int find_first_radix_bit(struct radix_tree_root *radix, unsigned long *retbits,
-                         unsigned long start, int nr)
-{
-        unsigned long *bits;
-        unsigned long *gang[4];
-        int found;
-        int ret;
-        int i;
-        int total_found = 0;
-        unsigned long slot;
-
-        slot = start / BIT_RADIX_BITS_PER_ARRAY;
-        ret = radix_tree_gang_lookup(radix, (void **)gang, slot,
-                                     ARRAY_SIZE(gang));
-        found = start % BIT_RADIX_BITS_PER_ARRAY;
-        for (i = 0; i < ret && nr > 0; i++) {
-                bits = gang[i];
-                while(nr > 0) {
-                        found = find_next_bit(bits + 1,
-                                              BIT_RADIX_BITS_PER_ARRAY,
-                                              found);
-                        if (found < BIT_RADIX_BITS_PER_ARRAY) {
-                                *retbits = bits[0] *
-                                        BIT_RADIX_BITS_PER_ARRAY + found;
-                                retbits++;
-                                nr--;
-                                total_found++;
-                                found++;
-                        } else
-                                break;
-                }
-                found = 0;
-        }
-        return total_found;
-}