Btrfs: add a radix back bit tree

Signed-off-by: Chris Mason <chris.mason@oracle.com>

6 files changed, 167 insertions, 57 deletions

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index be7d74cdca04..5346f706b2c5 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -3,7 +3,8 @@ ifneq ($(KERNELRELEASE),)
 
 obj-m  := btrfs.o
 btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
-           hash.o file-item.o inode-item.o inode-map.o disk-io.o transaction.o
+           hash.o file-item.o inode-item.o inode-map.o disk-io.o \
+           transaction.o bit-radix.o
 
 #btrfs-y := ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
 #         root-tree.o dir-item.o hash.o file-item.o inode-item.o \
diff --git a/fs/btrfs/bit-radix.c b/fs/btrfs/bit-radix.c
new file mode 100644
index 000000000000..43807cc3cce7
--- /dev/null
+++ b/fs/btrfs/bit-radix.c
@@ -0,0 +1,107 @@
+#include <linux/module.h>
+#include "bit-radix.h"
+
+#define BIT_ARRAY_BYTES 256
+#define BIT_RADIX_BITS_PER_ARRAY ((BIT_ARRAY_BYTES - sizeof(unsigned long)) * 8)
+
+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 = kmalloc(BIT_ARRAY_BYTES, GFP_NOIO);
+                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;
+        }
+        set_bit(bit_slot, bits + 1);
+        return 0;
+}
+
+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);
+        }
+        return 0;
+}
+
+int find_first_radix_bit(struct radix_tree_root *radix, unsigned long *retbits,
+                         int nr)
+{
+        unsigned long *bits;
+        unsigned long *gang[4];
+        int found;
+        int ret;
+        int i;
+        int total_found = 0;
+
+        ret = radix_tree_gang_lookup(radix, (void *)&gang, 0, ARRAY_SIZE(gang));
+        for (i = 0; i < ret && nr > 0; i++) {
+                found = 0;
+                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;
+                }
+        }
+        return total_found;
+}
diff --git a/fs/btrfs/bit-radix.h b/fs/btrfs/bit-radix.h
new file mode 100644
index 000000000000..56aad4c7d7f7
--- /dev/null
+++ b/fs/btrfs/bit-radix.h
@@ -0,0 +1,15 @@
+#ifndef __BIT_RADIX__
+#define __BIT_RADIX__
+#include <linux/radix-tree.h>
+
+int set_radix_bit(struct radix_tree_root *radix, unsigned long bit);
+int test_radix_bit(struct radix_tree_root *radix, unsigned long bit);
+int clear_radix_bit(struct radix_tree_root *radix, unsigned long bit);
+int find_first_radix_bit(struct radix_tree_root *radix, unsigned long *retbits,
+                         int nr);
+
+static inline void init_bit_radix(struct radix_tree_root *radix)
+{
+        INIT_RADIX_TREE(radix, GFP_NOFS);
+}
+#endif
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 68cafae6a850..0aa1052d9f67 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1,8 +1,8 @@
 #ifndef __BTRFS__
 #define __BTRFS__
 
-#include <linux/radix-tree.h>
 #include <linux/fs.h>
+#include "bit-radix.h"
 
 struct btrfs_trans_handle;
 struct btrfs_transaction;
@@ -222,6 +222,7 @@ struct btrfs_fs_info {
         struct btrfs_root *inode_root;
         struct btrfs_key current_insert;
         struct btrfs_key last_insert;
+        struct radix_tree_root pending_del_radix;
         struct radix_tree_root pinned_radix;
         u64 last_inode_alloc;
         u64 last_inode_alloc_dirid;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e32ddff55b0e..758a62aba063 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -104,7 +104,8 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         /* FIXME: don't be stupid */
         if (!btrfs_super_root(disk_super))
                 return NULL;
-        INIT_RADIX_TREE(&fs_info->pinned_radix, GFP_KERNEL);
+        init_bit_radix(&fs_info->pinned_radix);
+        init_bit_radix(&fs_info->pending_del_radix);
         fs_info->running_transaction = NULL;
         fs_info->fs_root = root;
         fs_info->tree_root = tree_root;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 369b960fce45..b14104276eea 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1,5 +1,4 @@
 #include <linux/module.h>
-#include <linux/radix-tree.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "print-tree.h"
@@ -12,15 +11,6 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
                                  btrfs_root *extent_root);
 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
                                btrfs_root *extent_root);
-/*
- * pending extents are blocks that we're trying to allocate in the extent
- * map while trying to grow the map because of other allocations.  To avoid
- * recursing, they are tagged in the radix tree and cleaned up after
- * other allocations are done.  The pending tag is also used in the same
- * manner for deletes.
- */
-#define CTREE_EXTENT_PENDING_DEL 0
-#define CTREE_EXTENT_PINNED 1
 
 static int inc_block_ref(struct btrfs_trans_handle *trans, struct btrfs_root
                          *root, u64 blocknr)
@@ -104,24 +94,21 @@ int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
                                btrfs_root *root)
 {
-        struct buffer_head *gang[8];
+        unsigned long gang[8];
         u64 first = 0;
         int ret;
         int i;
+        struct radix_tree_root *pinned_radix = &root->fs_info->pinned_radix;
 
         while(1) {
-                ret = radix_tree_gang_lookup_tag(&root->fs_info->pinned_radix,
-                                             (void **)gang, 0,
-                                             ARRAY_SIZE(gang),
-                                             CTREE_EXTENT_PINNED);
+                ret = find_first_radix_bit(pinned_radix, gang,
+                                           ARRAY_SIZE(gang));
                 if (!ret)
                         break;
                 if (!first)
-                        first = gang[0]->b_blocknr;
+                        first = gang[0];
                 for (i = 0; i < ret; i++) {
-                        radix_tree_delete(&root->fs_info->pinned_radix,
-                                          gang[i]->b_blocknr);
-                        brelse(gang[i]);
+                        clear_radix_bit(pinned_radix, gang[i]);
                 }
         }
         if (root->fs_info->last_insert.objectid > first)
@@ -161,29 +148,27 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
         return 0;
 }
 
-static int pin_down_block(struct btrfs_root *root, u64 blocknr, int tag)
+static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
 {
         int err;
-        struct buffer_head *bh = sb_getblk(root->fs_info->sb, blocknr);
         struct btrfs_header *header;
-        BUG_ON(!bh);
-
-        header = btrfs_buffer_header(bh);
-        if (btrfs_header_generation(header) ==
-            root->fs_info->running_transaction->transid) {
-                return 0;
-        }
-
-        err = radix_tree_insert(&root->fs_info->pinned_radix,
-                                blocknr, bh);
-        if (err && err != -EEXIST) {
-                BUG();
-                return err;
-        }
-        if (err == -EEXIST)
+        struct buffer_head *bh;
+
+        bh = sb_find_get_block(root->fs_info->sb, blocknr);
+        if (bh) {
+                header = btrfs_buffer_header(bh);
+                if (btrfs_header_generation(header) ==
+                    root->fs_info->running_transaction->transid) {
+                        brelse(bh);
+                        return 0;
+                }
                 brelse(bh);
-        radix_tree_tag_set(&root->fs_info->pinned_radix, blocknr,
-                           tag);
+        }
+        if (pending)
+                err = set_radix_bit(&root->fs_info->pending_del_radix, blocknr);
+        else
+                err = set_radix_bit(&root->fs_info->pinned_radix, blocknr);
+        BUG_ON(err);
         return 0;
 }
 
@@ -225,8 +210,7 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                 u64 super_blocks_used;
 
                 if (pin) {
-                        ret = pin_down_block(root, blocknr,
-                                             CTREE_EXTENT_PINNED);
+                        ret = pin_down_block(root, blocknr, 0);
                         BUG_ON(ret);
                 }
 
@@ -255,25 +239,26 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
         int ret;
         int wret;
         int err = 0;
-        struct buffer_head *gang[4];
+        unsigned long gang[4];
         int i;
-        struct radix_tree_root *radix = &extent_root->fs_info->pinned_radix;
+        struct radix_tree_root *pending_radix;
+        struct radix_tree_root *pinned_radix;
+
+        pending_radix = &extent_root->fs_info->pending_del_radix;
+        pinned_radix = &extent_root->fs_info->pinned_radix;
 
         while(1) {
-                ret = radix_tree_gang_lookup_tag(
-                                        &extent_root->fs_info->pinned_radix,
-                                        (void **)gang, 0,
-                                        ARRAY_SIZE(gang),
-                                        CTREE_EXTENT_PENDING_DEL);
+                ret = find_first_radix_bit(pending_radix, gang,
+                                           ARRAY_SIZE(gang));
                 if (!ret)
                         break;
                 for (i = 0; i < ret; i++) {
-                        radix_tree_tag_set(radix, gang[i]->b_blocknr,
-                                           CTREE_EXTENT_PINNED);
-                        radix_tree_tag_clear(radix, gang[i]->b_blocknr,
-                                             CTREE_EXTENT_PENDING_DEL);
+                        wret = set_radix_bit(pinned_radix, gang[i]);
+                        BUG_ON(wret);
+                        wret = clear_radix_bit(pending_radix, gang[i]);
+                        BUG_ON(wret);
                         wret = __free_extent(trans, extent_root,
-                                             gang[i]->b_blocknr, 1, 0);
+                                             gang[i], 1, 0);
                         if (wret)
                                 err = wret;
                 }
@@ -294,7 +279,7 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
 
         if (root == extent_root) {
                 t = find_tree_block(root, blocknr);
-                pin_down_block(root, blocknr, CTREE_EXTENT_PENDING_DEL);
+                pin_down_block(root, blocknr, 1);
                 return 0;
         }
         ret = __free_extent(trans, root, blocknr, num_blocks, pin);
@@ -393,7 +378,7 @@ check_pending:
         BUG_ON(ins->objectid < search_start);
         for (test_block = ins->objectid;
              test_block < ins->objectid + total_needed; test_block++) {
-                if (radix_tree_lookup(&root->fs_info->pinned_radix,
+                if (test_radix_bit(&root->fs_info->pinned_radix,
                                       test_block)) {
                         search_start = test_block + 1;
                         goto check_failed;