Merge branch 'devel-stable' into devel

Conflicts:
	MAINTAINERS
	arch/arm/mm/fault.c

1 files changed, 790 insertions, 213 deletions

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 4538e48581a5..af99b78b288e 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -16,45 +16,46 @@
  * Boston, MA 021110-1307, USA.
  */
 
+#include <linux/pagemap.h>
 #include <linux/sched.h>
+#include <linux/math64.h>
 #include "ctree.h"
 #include "free-space-cache.h"
 #include "transaction.h"
 
-struct btrfs_free_space {
-        struct rb_node bytes_index;
-        struct rb_node offset_index;
-        u64 offset;
-        u64 bytes;
-};
+#define BITS_PER_BITMAP         (PAGE_CACHE_SIZE * 8)
+#define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
 
-static int tree_insert_offset(struct rb_root *root, u64 offset,
-                              struct rb_node *node)
+static inline unsigned long offset_to_bit(u64 bitmap_start, u64 sectorsize,
+                                          u64 offset)
 {
-        struct rb_node **p = &root->rb_node;
-        struct rb_node *parent = NULL;
-        struct btrfs_free_space *info;
+        BUG_ON(offset < bitmap_start);
+        offset -= bitmap_start;
+        return (unsigned long)(div64_u64(offset, sectorsize));
+}
 
-        while (*p) {
-                parent = *p;
-                info = rb_entry(parent, struct btrfs_free_space, offset_index);
+static inline unsigned long bytes_to_bits(u64 bytes, u64 sectorsize)
+{
+        return (unsigned long)(div64_u64(bytes, sectorsize));
+}
 
-                if (offset < info->offset)
-                        p = &(*p)->rb_left;
-                else if (offset > info->offset)
-                        p = &(*p)->rb_right;
-                else
-                        return -EEXIST;
-        }
+static inline u64 offset_to_bitmap(struct btrfs_block_group_cache *block_group,
+                                   u64 offset)
+{
+        u64 bitmap_start;
+        u64 bytes_per_bitmap;
 
-        rb_link_node(node, parent, p);
-        rb_insert_color(node, root);
+        bytes_per_bitmap = BITS_PER_BITMAP * block_group->sectorsize;
+        bitmap_start = offset - block_group->key.objectid;
+        bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
+        bitmap_start *= bytes_per_bitmap;
+        bitmap_start += block_group->key.objectid;
 
-        return 0;
+        return bitmap_start;
 }
 
-static int tree_insert_bytes(struct rb_root *root, u64 bytes,
-                             struct rb_node *node)
+static int tree_insert_offset(struct rb_root *root, u64 offset,
+                              struct rb_node *node, int bitmap)
 {
         struct rb_node **p = &root->rb_node;
         struct rb_node *parent = NULL;
@@ -62,12 +63,34 @@ static int tree_insert_bytes(struct rb_root *root, u64 bytes,
 
         while (*p) {
                 parent = *p;
-                info = rb_entry(parent, struct btrfs_free_space, bytes_index);
+                info = rb_entry(parent, struct btrfs_free_space, offset_index);
 
-                if (bytes < info->bytes)
+                if (offset < info->offset) {
                         p = &(*p)->rb_left;
-                else
+                } else if (offset > info->offset) {
                         p = &(*p)->rb_right;
+                } else {
+                        /*
+                         * we could have a bitmap entry and an extent entry
+                         * share the same offset.  If this is the case, we want
+                         * the extent entry to always be found first if we do a
+                         * linear search through the tree, since we want to have
+                         * the quickest allocation time, and allocating from an
+                         * extent is faster than allocating from a bitmap.  So
+                         * if we're inserting a bitmap and we find an entry at
+                         * this offset, we want to go right, or after this entry
+                         * logically.  If we are inserting an extent and we've
+                         * found a bitmap, we want to go left, or before
+                         * logically.
+                         */
+                        if (bitmap) {
+                                WARN_ON(info->bitmap);
+                                p = &(*p)->rb_right;
+                        } else {
+                                WARN_ON(!info->bitmap);
+                                p = &(*p)->rb_left;
+                        }
+                }
         }
 
         rb_link_node(node, parent, p);
@@ -79,110 +102,143 @@ static int tree_insert_bytes(struct rb_root *root, u64 bytes,
 /*
  * searches the tree for the given offset.
  *
- * fuzzy == 1: this is used for allocations where we are given a hint of where
- * to look for free space.  Because the hint may not be completely on an offset
- * mark, or the hint may no longer point to free space we need to fudge our
- * results a bit.  So we look for free space starting at or after offset with at
- * least bytes size.  We prefer to find as close to the given offset as we can.
- * Also if the offset is within a free space range, then we will return the free
- * space that contains the given offset, which means we can return a free space
- * chunk with an offset before the provided offset.
- *
- * fuzzy == 0: this is just a normal tree search.  Give us the free space that
- * starts at the given offset which is at least bytes size, and if its not there
- * return NULL.
+ * fuzzy - If this is set, then we are trying to make an allocation, and we just
+ * want a section that has at least bytes size and comes at or after the given
+ * offset.
  */
-static struct btrfs_free_space *tree_search_offset(struct rb_root *root,
-                                                   u64 offset, u64 bytes,
-                                                   int fuzzy)
+static struct btrfs_free_space *
+tree_search_offset(struct btrfs_block_group_cache *block_group,
+                   u64 offset, int bitmap_only, int fuzzy)
 {
-        struct rb_node *n = root->rb_node;
-        struct btrfs_free_space *entry, *ret = NULL;
+        struct rb_node *n = block_group->free_space_offset.rb_node;
+        struct btrfs_free_space *entry, *prev = NULL;
+
+        /* find entry that is closest to the 'offset' */
+        while (1) {
+                if (!n) {
+                        entry = NULL;
+                        break;
+                }
 
-        while (n) {
                 entry = rb_entry(n, struct btrfs_free_space, offset_index);
+                prev = entry;
 
-                if (offset < entry->offset) {
-                        if (fuzzy &&
-                            (!ret || entry->offset < ret->offset) &&
-                            (bytes <= entry->bytes))
-                                ret = entry;
+                if (offset < entry->offset)
                         n = n->rb_left;
-                } else if (offset > entry->offset) {
-                        if (fuzzy &&
-                            (entry->offset + entry->bytes - 1) >= offset &&
-                            bytes <= entry->bytes) {
-                                ret = entry;
-                                break;
-                        }
+                else if (offset > entry->offset)
                         n = n->rb_right;
-                } else {
-                        if (bytes > entry->bytes) {
-                                n = n->rb_right;
-                                continue;
-                        }
-                        ret = entry;
+                else
                         break;
-                }
         }
 
-        return ret;
-}
-
-/*
- * return a chunk at least bytes size, as close to offset that we can get.
- */
-static struct btrfs_free_space *tree_search_bytes(struct rb_root *root,
-                                                  u64 offset, u64 bytes)
-{
-        struct rb_node *n = root->rb_node;
-        struct btrfs_free_space *entry, *ret = NULL;
+        if (bitmap_only) {
+                if (!entry)
+                        return NULL;
+                if (entry->bitmap)
+                        return entry;
 
-        while (n) {
-                entry = rb_entry(n, struct btrfs_free_space, bytes_index);
+                /*
+                 * bitmap entry and extent entry may share same offset,
+                 * in that case, bitmap entry comes after extent entry.
+                 */
+                n = rb_next(n);
+                if (!n)
+                        return NULL;
+                entry = rb_entry(n, struct btrfs_free_space, offset_index);
+                if (entry->offset != offset)
+                        return NULL;
 
-                if (bytes < entry->bytes) {
+                WARN_ON(!entry->bitmap);
+                return entry;
+        } else if (entry) {
+                if (entry->bitmap) {
                         /*
-                         * We prefer to get a hole size as close to the size we
-                         * are asking for so we don't take small slivers out of
-                         * huge holes, but we also want to get as close to the
-                         * offset as possible so we don't have a whole lot of
-                         * fragmentation.
+                         * if previous extent entry covers the offset,
+                         * we should return it instead of the bitmap entry
                          */
-                        if (offset <= entry->offset) {
-                                if (!ret)
-                                        ret = entry;
-                                else if (entry->bytes < ret->bytes)
-                                        ret = entry;
-                                else if (entry->offset < ret->offset)
-                                        ret = entry;
+                        n = &entry->offset_index;
+                        while (1) {
+                                n = rb_prev(n);
+                                if (!n)
+                                        break;
+                                prev = rb_entry(n, struct btrfs_free_space,
+                                                offset_index);
+                                if (!prev->bitmap) {
+                                        if (prev->offset + prev->bytes > offset)
+                                                entry = prev;
+                                        break;
+                                }
                         }
-                        n = n->rb_left;
-                } else if (bytes > entry->bytes) {
-                        n = n->rb_right;
+                }
+                return entry;
+        }
+
+        if (!prev)
+                return NULL;
+
+        /* find last entry before the 'offset' */
+        entry = prev;
+        if (entry->offset > offset) {
+                n = rb_prev(&entry->offset_index);
+                if (n) {
+                        entry = rb_entry(n, struct btrfs_free_space,
+                                        offset_index);
+                        BUG_ON(entry->offset > offset);
                 } else {
-                        /*
-                         * Ok we may have multiple chunks of the wanted size,
-                         * so we don't want to take the first one we find, we
-                         * want to take the one closest to our given offset, so
-                         * keep searching just in case theres a better match.
-                         */
-                        n = n->rb_right;
-                        if (offset > entry->offset)
-                                continue;
-                        else if (!ret || entry->offset < ret->offset)
-                                ret = entry;
+                        if (fuzzy)
+                                return entry;
+                        else
+                                return NULL;
                 }
         }
 
-        return ret;
+        if (entry->bitmap) {
+                n = &entry->offset_index;
+                while (1) {
+                        n = rb_prev(n);
+                        if (!n)
+                                break;
+                        prev = rb_entry(n, struct btrfs_free_space,
+                                        offset_index);
+                        if (!prev->bitmap) {
+                                if (prev->offset + prev->bytes > offset)
+                                        return prev;
+                                break;
+                        }
+                }
+                if (entry->offset + BITS_PER_BITMAP *
+                    block_group->sectorsize > offset)
+                        return entry;
+        } else if (entry->offset + entry->bytes > offset)
+                return entry;
+
+        if (!fuzzy)
+                return NULL;
+
+        while (1) {
+                if (entry->bitmap) {
+                        if (entry->offset + BITS_PER_BITMAP *
+                            block_group->sectorsize > offset)
+                                break;
+                } else {
+                        if (entry->offset + entry->bytes > offset)
+                                break;
+                }
+
+                n = rb_next(&entry->offset_index);
+                if (!n)
+                        return NULL;
+                entry = rb_entry(n, struct btrfs_free_space, offset_index);
+        }
+        return entry;
 }
 
 static void unlink_free_space(struct btrfs_block_group_cache *block_group,
                               struct btrfs_free_space *info)
 {
         rb_erase(&info->offset_index, &block_group->free_space_offset);
-        rb_erase(&info->bytes_index, &block_group->free_space_bytes);
+        block_group->free_extents--;
+        block_group->free_space -= info->bytes;
 }
 
 static int link_free_space(struct btrfs_block_group_cache *block_group,
@@ -190,17 +246,314 @@ static int link_free_space(struct btrfs_block_group_cache *block_group,
 {
         int ret = 0;
 
-
-        BUG_ON(!info->bytes);
+        BUG_ON(!info->bitmap && !info->bytes);
         ret = tree_insert_offset(&block_group->free_space_offset, info->offset,
-                                 &info->offset_index);
+                                 &info->offset_index, (info->bitmap != NULL));
         if (ret)
                 return ret;
 
-        ret = tree_insert_bytes(&block_group->free_space_bytes, info->bytes,
-                                &info->bytes_index);
-        if (ret)
-                return ret;
+        block_group->free_space += info->bytes;
+        block_group->free_extents++;
+        return ret;
+}
+
+static void recalculate_thresholds(struct btrfs_block_group_cache *block_group)
+{
+        u64 max_bytes, possible_bytes;
+
+        /*
+         * The goal is to keep the total amount of memory used per 1gb of space
+         * at or below 32k, so we need to adjust how much memory we allow to be
+         * used by extent based free space tracking
+         */
+        max_bytes = MAX_CACHE_BYTES_PER_GIG *
+                (div64_u64(block_group->key.offset, 1024 * 1024 * 1024));
+
+        possible_bytes = (block_group->total_bitmaps * PAGE_CACHE_SIZE) +
+                (sizeof(struct btrfs_free_space) *
+                 block_group->extents_thresh);
+
+        if (possible_bytes > max_bytes) {
+                int extent_bytes = max_bytes -
+                        (block_group->total_bitmaps * PAGE_CACHE_SIZE);
+
+                if (extent_bytes <= 0) {
+                        block_group->extents_thresh = 0;
+                        return;
+                }
+
+                block_group->extents_thresh = extent_bytes /
+                        (sizeof(struct btrfs_free_space));
+        }
+}
+
+static void bitmap_clear_bits(struct btrfs_block_group_cache *block_group,
+                              struct btrfs_free_space *info, u64 offset,
+                              u64 bytes)
+{
+        unsigned long start, end;
+        unsigned long i;
+
+        start = offset_to_bit(info->offset, block_group->sectorsize, offset);
+        end = start + bytes_to_bits(bytes, block_group->sectorsize);
+        BUG_ON(end > BITS_PER_BITMAP);
+
+        for (i = start; i < end; i++)
+                clear_bit(i, info->bitmap);
+
+        info->bytes -= bytes;
+        block_group->free_space -= bytes;
+}
+
+static void bitmap_set_bits(struct btrfs_block_group_cache *block_group,
+                            struct btrfs_free_space *info, u64 offset,
+                            u64 bytes)
+{
+        unsigned long start, end;
+        unsigned long i;
+
+        start = offset_to_bit(info->offset, block_group->sectorsize, offset);
+        end = start + bytes_to_bits(bytes, block_group->sectorsize);
+        BUG_ON(end > BITS_PER_BITMAP);
+
+        for (i = start; i < end; i++)
+                set_bit(i, info->bitmap);
+
+        info->bytes += bytes;
+        block_group->free_space += bytes;
+}
+
+static int search_bitmap(struct btrfs_block_group_cache *block_group,
+                         struct btrfs_free_space *bitmap_info, u64 *offset,
+                         u64 *bytes)
+{
+        unsigned long found_bits = 0;
+        unsigned long bits, i;
+        unsigned long next_zero;
+
+        i = offset_to_bit(bitmap_info->offset, block_group->sectorsize,
+                          max_t(u64, *offset, bitmap_info->offset));
+        bits = bytes_to_bits(*bytes, block_group->sectorsize);
+
+        for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
+             i < BITS_PER_BITMAP;
+             i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
+                next_zero = find_next_zero_bit(bitmap_info->bitmap,
+                                               BITS_PER_BITMAP, i);
+                if ((next_zero - i) >= bits) {
+                        found_bits = next_zero - i;
+                        break;
+                }
+                i = next_zero;
+        }
+
+        if (found_bits) {
+                *offset = (u64)(i * block_group->sectorsize) +
+                        bitmap_info->offset;
+                *bytes = (u64)(found_bits) * block_group->sectorsize;
+                return 0;
+        }
+
+        return -1;
+}
+
+static struct btrfs_free_space *find_free_space(struct btrfs_block_group_cache
+                                                *block_group, u64 *offset,
+                                                u64 *bytes, int debug)
+{
+        struct btrfs_free_space *entry;
+        struct rb_node *node;
+        int ret;
+
+        if (!block_group->free_space_offset.rb_node)
+                return NULL;
+
+        entry = tree_search_offset(block_group,
+                                   offset_to_bitmap(block_group, *offset),
+                                   0, 1);
+        if (!entry)
+                return NULL;
+
+        for (node = &entry->offset_index; node; node = rb_next(node)) {
+                entry = rb_entry(node, struct btrfs_free_space, offset_index);
+                if (entry->bytes < *bytes)
+                        continue;
+
+                if (entry->bitmap) {
+                        ret = search_bitmap(block_group, entry, offset, bytes);
+                        if (!ret)
+                                return entry;
+                        continue;
+                }
+
+                *offset = entry->offset;
+                *bytes = entry->bytes;
+                return entry;
+        }
+
+        return NULL;
+}
+
+static void add_new_bitmap(struct btrfs_block_group_cache *block_group,
+                           struct btrfs_free_space *info, u64 offset)
+{
+        u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
+        int max_bitmaps = (int)div64_u64(block_group->key.offset +
+                                         bytes_per_bg - 1, bytes_per_bg);
+        BUG_ON(block_group->total_bitmaps >= max_bitmaps);
+
+        info->offset = offset_to_bitmap(block_group, offset);
+        link_free_space(block_group, info);
+        block_group->total_bitmaps++;
+
+        recalculate_thresholds(block_group);
+}
+
+static noinline int remove_from_bitmap(struct btrfs_block_group_cache *block_group,
+                              struct btrfs_free_space *bitmap_info,
+                              u64 *offset, u64 *bytes)
+{
+        u64 end;
+
+again:
+        end = bitmap_info->offset +
+                (u64)(BITS_PER_BITMAP * block_group->sectorsize) - 1;
+
+        if (*offset > bitmap_info->offset && *offset + *bytes > end) {
+                bitmap_clear_bits(block_group, bitmap_info, *offset,
+                                  end - *offset + 1);
+                *bytes -= end - *offset + 1;
+                *offset = end + 1;
+        } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
+                bitmap_clear_bits(block_group, bitmap_info, *offset, *bytes);
+                *bytes = 0;
+        }
+
+        if (*bytes) {
+                if (!bitmap_info->bytes) {
+                        unlink_free_space(block_group, bitmap_info);
+                        kfree(bitmap_info->bitmap);
+                        kfree(bitmap_info);
+                        block_group->total_bitmaps--;
+                        recalculate_thresholds(block_group);
+                }
+
+                bitmap_info = tree_search_offset(block_group,
+                                                 offset_to_bitmap(block_group,
+                                                                  *offset),
+                                                 1, 0);
+                if (!bitmap_info)
+                        return -EINVAL;
+
+                if (!bitmap_info->bitmap)
+                        return -EAGAIN;
+
+                goto again;
+        } else if (!bitmap_info->bytes) {
+                unlink_free_space(block_group, bitmap_info);
+                kfree(bitmap_info->bitmap);
+                kfree(bitmap_info);
+                block_group->total_bitmaps--;
+                recalculate_thresholds(block_group);
+        }
+
+        return 0;
+}
+
+static int insert_into_bitmap(struct btrfs_block_group_cache *block_group,
+                              struct btrfs_free_space *info)
+{
+        struct btrfs_free_space *bitmap_info;
+        int added = 0;
+        u64 bytes, offset, end;
+        int ret;
+
+        /*
+         * If we are below the extents threshold then we can add this as an
+         * extent, and don't have to deal with the bitmap
+         */
+        if (block_group->free_extents < block_group->extents_thresh &&
+            info->bytes > block_group->sectorsize * 4)
+                return 0;
+
+        /*
+         * some block groups are so tiny they can't be enveloped by a bitmap, so
+         * don't even bother to create a bitmap for this
+         */
+        if (BITS_PER_BITMAP * block_group->sectorsize >
+            block_group->key.offset)
+                return 0;
+
+        bytes = info->bytes;
+        offset = info->offset;
+
+again:
+        bitmap_info = tree_search_offset(block_group,
+                                         offset_to_bitmap(block_group, offset),
+                                         1, 0);
+        if (!bitmap_info) {
+                BUG_ON(added);
+                goto new_bitmap;
+        }
+
+        end = bitmap_info->offset +
+                (u64)(BITS_PER_BITMAP * block_group->sectorsize);
+
+        if (offset >= bitmap_info->offset && offset + bytes > end) {
+                bitmap_set_bits(block_group, bitmap_info, offset,
+                                end - offset);
+                bytes -= end - offset;
+                offset = end;
+                added = 0;
+        } else if (offset >= bitmap_info->offset && offset + bytes <= end) {
+                bitmap_set_bits(block_group, bitmap_info, offset, bytes);
+                bytes = 0;
+        } else {
+                BUG();
+        }
+
+        if (!bytes) {
+                ret = 1;
+                goto out;
+        } else
+                goto again;
+
+new_bitmap:
+        if (info && info->bitmap) {
+                add_new_bitmap(block_group, info, offset);
+                added = 1;
+                info = NULL;
+                goto again;
+        } else {
+                spin_unlock(&block_group->tree_lock);
+
+                /* no pre-allocated info, allocate a new one */
+                if (!info) {
+                        info = kzalloc(sizeof(struct btrfs_free_space),
+                                       GFP_NOFS);
+                        if (!info) {
+                                spin_lock(&block_group->tree_lock);
+                                ret = -ENOMEM;
+                                goto out;
+                        }
+                }
+
+                /* allocate the bitmap */
+                info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
+                spin_lock(&block_group->tree_lock);
+                if (!info->bitmap) {
+                        ret = -ENOMEM;
+                        goto out;
+                }
+                goto again;
+        }
+
+out:
+        if (info) {
+                if (info->bitmap)
+                        kfree(info->bitmap);
+                kfree(info);
+        }
 
         return ret;
 }
@@ -208,8 +561,8 @@ static int link_free_space(struct btrfs_block_group_cache *block_group,
 int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
                          u64 offset, u64 bytes)
 {
-        struct btrfs_free_space *right_info;
-        struct btrfs_free_space *left_info;
+        struct btrfs_free_space *right_info = NULL;
+        struct btrfs_free_space *left_info = NULL;
         struct btrfs_free_space *info = NULL;
         int ret = 0;
 
@@ -227,18 +580,38 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
          * are adding, if there is remove that struct and add a new one to
          * cover the entire range
          */
-        right_info = tree_search_offset(&block_group->free_space_offset,
-                                        offset+bytes, 0, 0);
-        left_info = tree_search_offset(&block_group->free_space_offset,
-                                       offset-1, 0, 1);
+        right_info = tree_search_offset(block_group, offset + bytes, 0, 0);
+        if (right_info && rb_prev(&right_info->offset_index))
+                left_info = rb_entry(rb_prev(&right_info->offset_index),
+                                     struct btrfs_free_space, offset_index);
+        else
+                left_info = tree_search_offset(block_group, offset - 1, 0, 0);
 
-        if (right_info) {
+        /*
+         * If there was no extent directly to the left or right of this new
+         * extent then we know we're going to have to allocate a new extent, so
+         * before we do that see if we need to drop this into a bitmap
+         */
+        if ((!left_info || left_info->bitmap) &&
+            (!right_info || right_info->bitmap)) {
+                ret = insert_into_bitmap(block_group, info);
+
+                if (ret < 0) {
+                        goto out;
+                } else if (ret) {
+                        ret = 0;
+                        goto out;
+                }
+        }
+
+        if (right_info && !right_info->bitmap) {
                 unlink_free_space(block_group, right_info);
                 info->bytes += right_info->bytes;
                 kfree(right_info);
         }
 
-        if (left_info && left_info->offset + left_info->bytes == offset) {
+        if (left_info && !left_info->bitmap &&
+            left_info->offset + left_info->bytes == offset) {
                 unlink_free_space(block_group, left_info);
                 info->offset = left_info->offset;
                 info->bytes += left_info->bytes;
@@ -248,11 +621,11 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
         ret = link_free_space(block_group, info);
         if (ret)
                 kfree(info);
-
+out:
         spin_unlock(&block_group->tree_lock);
 
         if (ret) {
-                printk(KERN_ERR "btrfs: unable to add free space :%d\n", ret);
+                printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
                 BUG_ON(ret == -EEXIST);
         }
 
@@ -263,40 +636,65 @@ int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
                             u64 offset, u64 bytes)
 {
         struct btrfs_free_space *info;
+        struct btrfs_free_space *next_info = NULL;
         int ret = 0;
 
         spin_lock(&block_group->tree_lock);
 
-        info = tree_search_offset(&block_group->free_space_offset, offset, 0,
-                                  1);
-        if (info && info->offset == offset) {
-                if (info->bytes < bytes) {
-                        printk(KERN_ERR "Found free space at %llu, size %llu,"
-                               "trying to use %llu\n",
-                               (unsigned long long)info->offset,
-                               (unsigned long long)info->bytes,
-                               (unsigned long long)bytes);
+again:
+        info = tree_search_offset(block_group, offset, 0, 0);
+        if (!info) {
+                WARN_ON(1);
+                goto out_lock;
+        }
+
+        if (info->bytes < bytes && rb_next(&info->offset_index)) {
+                u64 end;
+                next_info = rb_entry(rb_next(&info->offset_index),
+                                             struct btrfs_free_space,
+                                             offset_index);
+
+                if (next_info->bitmap)
+                        end = next_info->offset + BITS_PER_BITMAP *
+                                block_group->sectorsize - 1;
+                else
+                        end = next_info->offset + next_info->bytes;
+
+                if (next_info->bytes < bytes ||
+                    next_info->offset > offset || offset > end) {
+                        printk(KERN_CRIT "Found free space at %llu, size %llu,"
+                              " trying to use %llu\n",
+                              (unsigned long long)info->offset,
+                              (unsigned long long)info->bytes,
+                              (unsigned long long)bytes);
                         WARN_ON(1);
                         ret = -EINVAL;
-                        spin_unlock(&block_group->tree_lock);
-                        goto out;
+                        goto out_lock;
                 }
-                unlink_free_space(block_group, info);
 
-                if (info->bytes == bytes) {
-                        kfree(info);
-                        spin_unlock(&block_group->tree_lock);
-                        goto out;
+                info = next_info;
+        }
+
+        if (info->bytes == bytes) {
+                unlink_free_space(block_group, info);
+                if (info->bitmap) {
+                        kfree(info->bitmap);
+                        block_group->total_bitmaps--;
                 }
+                kfree(info);
+                goto out_lock;
+        }
 
+        if (!info->bitmap && info->offset == offset) {
+                unlink_free_space(block_group, info);
                 info->offset += bytes;
                 info->bytes -= bytes;
+                link_free_space(block_group, info);
+                goto out_lock;
+        }
 
-                ret = link_free_space(block_group, info);
-                spin_unlock(&block_group->tree_lock);
-                BUG_ON(ret);
-        } else if (info && info->offset < offset &&
-                   info->offset + info->bytes >= offset + bytes) {
+        if (!info->bitmap && info->offset <= offset &&
+            info->offset + info->bytes >= offset + bytes) {
                 u64 old_start = info->offset;
                 /*
                  * we're freeing space in the middle of the info,
@@ -312,7 +710,9 @@ int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
                         info->offset = offset + bytes;
                         info->bytes = old_end - info->offset;
                         ret = link_free_space(block_group, info);
-                        BUG_ON(ret);
+                        WARN_ON(ret);
+                        if (ret)
+                                goto out_lock;
                 } else {
                         /* the hole we're creating ends at the end
                          * of the info struct, just free the info
@@ -320,32 +720,22 @@ int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
                         kfree(info);
                 }
                 spin_unlock(&block_group->tree_lock);
-                /* step two, insert a new info struct to cover anything
-                 * before the hole
+
+                /* step two, insert a new info struct to cover
+                 * anything before the hole
                  */
                 ret = btrfs_add_free_space(block_group, old_start,
                                            offset - old_start);
-                BUG_ON(ret);
-        } else {
-                spin_unlock(&block_group->tree_lock);
-                if (!info) {
-                        printk(KERN_ERR "couldn't find space %llu to free\n",
-                               (unsigned long long)offset);
-                        printk(KERN_ERR "cached is %d, offset %llu bytes %llu\n",
-                               block_group->cached,
-                               (unsigned long long)block_group->key.objectid,
-                               (unsigned long long)block_group->key.offset);
-                        btrfs_dump_free_space(block_group, bytes);
-                } else if (info) {
-                        printk(KERN_ERR "hmm, found offset=%llu bytes=%llu, "
-                               "but wanted offset=%llu bytes=%llu\n",
-                               (unsigned long long)info->offset,
-                               (unsigned long long)info->bytes,
-                               (unsigned long long)offset,
-                               (unsigned long long)bytes);
-                }
-                WARN_ON(1);
+                WARN_ON(ret);
+                goto out;
         }
+
+        ret = remove_from_bitmap(block_group, info, &offset, &bytes);
+        if (ret == -EAGAIN)
+                goto again;
+        BUG_ON(ret);
+out_lock:
+        spin_unlock(&block_group->tree_lock);
 out:
         return ret;
 }
@@ -361,10 +751,13 @@ void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
                 info = rb_entry(n, struct btrfs_free_space, offset_index);
                 if (info->bytes >= bytes)
                         count++;
-                printk(KERN_ERR "entry offset %llu, bytes %llu\n",
+                printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
                        (unsigned long long)info->offset,
-                       (unsigned long long)info->bytes);
+                       (unsigned long long)info->bytes,
+                       (info->bitmap) ? "yes" : "no");
         }
+        printk(KERN_INFO "block group has cluster?: %s\n",
+               list_empty(&block_group->cluster_list) ? "no" : "yes");
         printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
                "\n", count);
 }
@@ -397,26 +790,35 @@ __btrfs_return_cluster_to_free_space(
 {
         struct btrfs_free_space *entry;
         struct rb_node *node;
+        bool bitmap;
 
         spin_lock(&cluster->lock);
         if (cluster->block_group != block_group)
                 goto out;
 
+        bitmap = cluster->points_to_bitmap;
+        cluster->block_group = NULL;
         cluster->window_start = 0;
+        list_del_init(&cluster->block_group_list);
+        cluster->points_to_bitmap = false;
+
+        if (bitmap)
+                goto out;
+
         node = rb_first(&cluster->root);
-        while(node) {
+        while (node) {
                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
                 node = rb_next(&entry->offset_index);
                 rb_erase(&entry->offset_index, &cluster->root);
-                link_free_space(block_group, entry);
+                BUG_ON(entry->bitmap);
+                tree_insert_offset(&block_group->free_space_offset,
+                                   entry->offset, &entry->offset_index, 0);
         }
-        list_del_init(&cluster->block_group_list);
-
-        btrfs_put_block_group(cluster->block_group);
-        cluster->block_group = NULL;
         cluster->root.rb_node = NULL;
+
 out:
         spin_unlock(&cluster->lock);
+        btrfs_put_block_group(block_group);
         return 0;
 }
 
@@ -425,20 +827,28 @@ void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
         struct btrfs_free_space *info;
         struct rb_node *node;
         struct btrfs_free_cluster *cluster;
-        struct btrfs_free_cluster *safe;
+        struct list_head *head;
 
         spin_lock(&block_group->tree_lock);
-
-        list_for_each_entry_safe(cluster, safe, &block_group->cluster_list,
-                                 block_group_list) {
+        while ((head = block_group->cluster_list.next) !=
+               &block_group->cluster_list) {
+                cluster = list_entry(head, struct btrfs_free_cluster,
+                                     block_group_list);
 
                 WARN_ON(cluster->block_group != block_group);
                 __btrfs_return_cluster_to_free_space(block_group, cluster);
+                if (need_resched()) {
+                        spin_unlock(&block_group->tree_lock);
+                        cond_resched();
+                        spin_lock(&block_group->tree_lock);
+                }
         }
 
-        while ((node = rb_last(&block_group->free_space_bytes)) != NULL) {
-                info = rb_entry(node, struct btrfs_free_space, bytes_index);
+        while ((node = rb_last(&block_group->free_space_offset)) != NULL) {
+                info = rb_entry(node, struct btrfs_free_space, offset_index);
                 unlink_free_space(block_group, info);
+                if (info->bitmap)
+                        kfree(info->bitmap);
                 kfree(info);
                 if (need_resched()) {
                         spin_unlock(&block_group->tree_lock);
@@ -446,6 +856,7 @@ void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
                         spin_lock(&block_group->tree_lock);
                 }
         }
+
         spin_unlock(&block_group->tree_lock);
 }
 
@@ -453,25 +864,35 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
                                u64 offset, u64 bytes, u64 empty_size)
 {
         struct btrfs_free_space *entry = NULL;
+        u64 bytes_search = bytes + empty_size;
         u64 ret = 0;
 
         spin_lock(&block_group->tree_lock);
-        entry = tree_search_offset(&block_group->free_space_offset, offset,
-                                   bytes + empty_size, 1);
+        entry = find_free_space(block_group, &offset, &bytes_search, 0);
         if (!entry)
-                entry = tree_search_bytes(&block_group->free_space_bytes,
-                                          offset, bytes + empty_size);
-        if (entry) {
+                goto out;
+
+        ret = offset;
+        if (entry->bitmap) {
+                bitmap_clear_bits(block_group, entry, offset, bytes);
+                if (!entry->bytes) {
+                        unlink_free_space(block_group, entry);
+                        kfree(entry->bitmap);
+                        kfree(entry);
+                        block_group->total_bitmaps--;
+                        recalculate_thresholds(block_group);
+                }
+        } else {
                 unlink_free_space(block_group, entry);
-                ret = entry->offset;
                 entry->offset += bytes;
                 entry->bytes -= bytes;
-
                 if (!entry->bytes)
                         kfree(entry);
                 else
                         link_free_space(block_group, entry);
         }
+
+out:
         spin_unlock(&block_group->tree_lock);
 
         return ret;
@@ -517,6 +938,47 @@ int btrfs_return_cluster_to_free_space(
         return ret;
 }
 
+static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
+                                   struct btrfs_free_cluster *cluster,
+                                   u64 bytes, u64 min_start)
+{
+        struct btrfs_free_space *entry;
+        int err;
+        u64 search_start = cluster->window_start;
+        u64 search_bytes = bytes;
+        u64 ret = 0;
+
+        spin_lock(&block_group->tree_lock);
+        spin_lock(&cluster->lock);
+
+        if (!cluster->points_to_bitmap)
+                goto out;
+
+        if (cluster->block_group != block_group)
+                goto out;
+
+        entry = tree_search_offset(block_group, search_start, 0, 0);
+
+        if (!entry || !entry->bitmap)
+                goto out;
+
+        search_start = min_start;
+        search_bytes = bytes;
+
+        err = search_bitmap(block_group, entry, &search_start,
+                            &search_bytes);
+        if (err)
+                goto out;
+
+        ret = search_start;
+        bitmap_clear_bits(block_group, entry, ret, bytes);
+out:
+        spin_unlock(&cluster->lock);
+        spin_unlock(&block_group->tree_lock);
+
+        return ret;
+}
+
 /*
  * given a cluster, try to allocate 'bytes' from it, returns 0
  * if it couldn't find anything suitably large, or a logical disk offset
@@ -530,6 +992,10 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
         struct rb_node *node;
         u64 ret = 0;
 
+        if (cluster->points_to_bitmap)
+                return btrfs_alloc_from_bitmap(block_group, cluster, bytes,
+                                               min_start);
+
         spin_lock(&cluster->lock);
         if (bytes > cluster->max_size)
                 goto out;
@@ -567,9 +1033,73 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
         }
 out:
         spin_unlock(&cluster->lock);
+
         return ret;
 }
 
+static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
+                                struct btrfs_free_space *entry,
+                                struct btrfs_free_cluster *cluster,
+                                u64 offset, u64 bytes, u64 min_bytes)
+{
+        unsigned long next_zero;
+        unsigned long i;
+        unsigned long search_bits;
+        unsigned long total_bits;
+        unsigned long found_bits;
+        unsigned long start = 0;
+        unsigned long total_found = 0;
+        bool found = false;
+
+        i = offset_to_bit(entry->offset, block_group->sectorsize,
+                          max_t(u64, offset, entry->offset));
+        search_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
+        total_bits = bytes_to_bits(bytes, block_group->sectorsize);
+
+again:
+        found_bits = 0;
+        for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
+             i < BITS_PER_BITMAP;
+             i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
+                next_zero = find_next_zero_bit(entry->bitmap,
+                                               BITS_PER_BITMAP, i);
+                if (next_zero - i >= search_bits) {
+                        found_bits = next_zero - i;
+                        break;
+                }
+                i = next_zero;
+        }
+
+        if (!found_bits)
+                return -1;
+
+        if (!found) {
+                start = i;
+                found = true;
+        }
+
+        total_found += found_bits;
+
+        if (cluster->max_size < found_bits * block_group->sectorsize)
+                cluster->max_size = found_bits * block_group->sectorsize;
+
+        if (total_found < total_bits) {
+                i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero);
+                if (i - start > total_bits * 2) {
+                        total_found = 0;
+                        cluster->max_size = 0;
+                        found = false;
+                }
+                goto again;
+        }
+
+        cluster->window_start = start * block_group->sectorsize +
+                entry->offset;
+        cluster->points_to_bitmap = true;
+
+        return 0;
+}
+
 /*
  * here we try to find a cluster of blocks in a block group.  The goal
  * is to find at least bytes free and up to empty_size + bytes free.
@@ -587,12 +1117,12 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
         struct btrfs_free_space *entry = NULL;
         struct rb_node *node;
         struct btrfs_free_space *next;
-        struct btrfs_free_space *last;
+        struct btrfs_free_space *last = NULL;
         u64 min_bytes;
         u64 window_start;
         u64 window_free;
         u64 max_extent = 0;
-        int total_retries = 0;
+        bool found_bitmap = false;
         int ret;
 
         /* for metadata, allow allocates with more holes */
@@ -620,31 +1150,80 @@ int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
                 goto out;
         }
 again:
-        min_bytes = min(min_bytes, bytes + empty_size);
-        entry = tree_search_bytes(&block_group->free_space_bytes,
-                                  offset, min_bytes);
+        entry = tree_search_offset(block_group, offset, found_bitmap, 1);
         if (!entry) {
                 ret = -ENOSPC;
                 goto out;
         }
+
+        /*
+         * If found_bitmap is true, we exhausted our search for extent entries,
+         * and we just want to search all of the bitmaps that we can find, and
+         * ignore any extent entries we find.
+         */
+        while (entry->bitmap || found_bitmap ||
+               (!entry->bitmap && entry->bytes < min_bytes)) {
+                struct rb_node *node = rb_next(&entry->offset_index);
+
+                if (entry->bitmap && entry->bytes > bytes + empty_size) {
+                        ret = btrfs_bitmap_cluster(block_group, entry, cluster,
+                                                   offset, bytes + empty_size,
+                                                   min_bytes);
+                        if (!ret)
+                                goto got_it;
+                }
+
+                if (!node) {
+                        ret = -ENOSPC;
+                        goto out;
+                }
+                entry = rb_entry(node, struct btrfs_free_space, offset_index);
+        }
+
+        /*
+         * We already searched all the extent entries from the passed in offset
+         * to the end and didn't find enough space for the cluster, and we also
+         * didn't find any bitmaps that met our criteria, just go ahead and exit
+         */
+        if (found_bitmap) {
+                ret = -ENOSPC;
+                goto out;
+        }
+
+        cluster->points_to_bitmap = false;
         window_start = entry->offset;
         window_free = entry->bytes;
         last = entry;
         max_extent = entry->bytes;
 
-        while(1) {
+        while (1) {
                 /* out window is just right, lets fill it */
                 if (window_free >= bytes + empty_size)
                         break;
 
                 node = rb_next(&last->offset_index);
                 if (!node) {
+                        if (found_bitmap)
+                                goto again;
                         ret = -ENOSPC;
                         goto out;
                 }
                 next = rb_entry(node, struct btrfs_free_space, offset_index);
 
                 /*
+                 * we found a bitmap, so if this search doesn't result in a
+                 * cluster, we know to go and search again for the bitmaps and
+                 * start looking for space there
+                 */
+                if (next->bitmap) {
+                        if (!found_bitmap)
+                                offset = next->offset;
+                        found_bitmap = true;
+                        last = next;
+                        continue;
+                }
+
+                /*
                  * we haven't filled the empty size and the window is
                  * very large.  reset and try again
                  */
@@ -655,19 +1234,6 @@ again:
                         window_free = entry->bytes;
                         last = entry;
                         max_extent = 0;
-                        total_retries++;
-                        if (total_retries % 64 == 0) {
-                                if (min_bytes >= (bytes + empty_size)) {
-                                        ret = -ENOSPC;
-                                        goto out;
-                                }
-                                /*
-                                 * grow our allocation a bit, we're not having
-                                 * much luck
-                                 */
-                                min_bytes *= 2;
-                                goto again;
-                        }
                 } else {
                         last = next;
                         window_free += next->bytes;
@@ -685,11 +1251,19 @@ again:
          * The cluster includes an rbtree, but only uses the offset index
          * of each free space cache entry.
          */
-        while(1) {
+        while (1) {
                 node = rb_next(&entry->offset_index);
-                unlink_free_space(block_group, entry);
+                if (entry->bitmap && node) {
+                        entry = rb_entry(node, struct btrfs_free_space,
+                                         offset_index);
+                        continue;
+                } else if (entry->bitmap && !node) {
+                        break;
+                }
+
+                rb_erase(&entry->offset_index, &block_group->free_space_offset);
                 ret = tree_insert_offset(&cluster->root, entry->offset,
-                                         &entry->offset_index);
+                                         &entry->offset_index, 0);
                 BUG_ON(ret);
 
                 if (!node || entry == last)
@@ -697,8 +1271,10 @@ again:
 
                 entry = rb_entry(node, struct btrfs_free_space, offset_index);
         }
-        ret = 0;
+
         cluster->max_size = max_extent;
+got_it:
+        ret = 0;
         atomic_inc(&block_group->count);
         list_add_tail(&cluster->block_group_list, &block_group->cluster_list);
         cluster->block_group = block_group;
@@ -718,6 +1294,7 @@ void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
         spin_lock_init(&cluster->refill_lock);
         cluster->root.rb_node = NULL;
         cluster->max_size = 0;
+        cluster->points_to_bitmap = false;
         INIT_LIST_HEAD(&cluster->block_group_list);
         cluster->block_group = NULL;
 }