diff options
Diffstat (limited to 'fs/btrfs/free-space-cache.c')
-rw-r--r-- | fs/btrfs/free-space-cache.c | 82 |
1 files changed, 63 insertions, 19 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 59ea2e4349c9..1f84fc09c1a8 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -1356,6 +1356,8 @@ static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl) u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit; int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg); + max_bitmaps = max(max_bitmaps, 1); + BUG_ON(ctl->total_bitmaps > max_bitmaps); /* @@ -1463,10 +1465,14 @@ static int search_bitmap(struct btrfs_free_space_ctl *ctl, } static struct btrfs_free_space * -find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes) +find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes, + unsigned long align) { struct btrfs_free_space *entry; struct rb_node *node; + u64 ctl_off; + u64 tmp; + u64 align_off; int ret; if (!ctl->free_space_offset.rb_node) @@ -1481,15 +1487,34 @@ find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes) if (entry->bytes < *bytes) continue; + /* make sure the space returned is big enough + * to match our requested alignment + */ + if (*bytes >= align) { + ctl_off = entry->offset - ctl->start; + tmp = ctl_off + align - 1;; + do_div(tmp, align); + tmp = tmp * align + ctl->start; + align_off = tmp - entry->offset; + } else { + align_off = 0; + tmp = entry->offset; + } + + if (entry->bytes < *bytes + align_off) + continue; + if (entry->bitmap) { - ret = search_bitmap(ctl, entry, offset, bytes); - if (!ret) + ret = search_bitmap(ctl, entry, &tmp, bytes); + if (!ret) { + *offset = tmp; return entry; + } continue; } - *offset = entry->offset; - *bytes = entry->bytes; + *offset = tmp; + *bytes = entry->bytes - align_off; return entry; } @@ -1636,10 +1661,14 @@ static bool use_bitmap(struct btrfs_free_space_ctl *ctl, } /* - * 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 + * The original block groups from mkfs can be really small, like 8 + * megabytes, so don't bother with a bitmap for those entries. However + * some block groups can be smaller than what a bitmap would cover but + * are still large enough that they could overflow the 32k memory limit, + * so allow those block groups to still be allowed to have a bitmap + * entry. */ - if (BITS_PER_BITMAP * ctl->unit > block_group->key.offset) + if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset) return false; return true; @@ -1862,11 +1891,13 @@ int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, { struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; struct btrfs_free_space *info; - int ret = 0; + int ret; + bool re_search = false; spin_lock(&ctl->tree_lock); again: + ret = 0; if (!bytes) goto out_lock; @@ -1879,17 +1910,17 @@ again: info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 1, 0); if (!info) { - /* the tree logging code might be calling us before we - * have fully loaded the free space rbtree for this - * block group. So it is possible the entry won't - * be in the rbtree yet at all. The caching code - * will make sure not to put it in the rbtree if - * the logging code has pinned it. + /* + * If we found a partial bit of our free space in a + * bitmap but then couldn't find the other part this may + * be a problem, so WARN about it. */ + WARN_ON(re_search); goto out_lock; } } + re_search = false; if (!info->bitmap) { unlink_free_space(ctl, info); if (offset == info->offset) { @@ -1935,8 +1966,10 @@ again: } ret = remove_from_bitmap(ctl, info, &offset, &bytes); - if (ret == -EAGAIN) + if (ret == -EAGAIN) { + re_search = true; goto again; + } BUG_ON(ret); /* logic error */ out_lock: spin_unlock(&ctl->tree_lock); @@ -2091,9 +2124,12 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group, struct btrfs_free_space *entry = NULL; u64 bytes_search = bytes + empty_size; u64 ret = 0; + u64 align_gap = 0; + u64 align_gap_len = 0; spin_lock(&ctl->tree_lock); - entry = find_free_space(ctl, &offset, &bytes_search); + entry = find_free_space(ctl, &offset, &bytes_search, + block_group->full_stripe_len); if (!entry) goto out; @@ -2103,9 +2139,15 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group, if (!entry->bytes) free_bitmap(ctl, entry); } else { + unlink_free_space(ctl, entry); - entry->offset += bytes; - entry->bytes -= bytes; + align_gap_len = offset - entry->offset; + align_gap = entry->offset; + + entry->offset = offset + bytes; + WARN_ON(entry->bytes < bytes + align_gap_len); + + entry->bytes -= bytes + align_gap_len; if (!entry->bytes) kmem_cache_free(btrfs_free_space_cachep, entry); else @@ -2115,6 +2157,8 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group, out: spin_unlock(&ctl->tree_lock); + if (align_gap_len) + __btrfs_add_free_space(ctl, align_gap, align_gap_len); return ret; } |