Merge branch 'raid56-experimental' into for-linus-3.9

[android-x86/kernel.git] / fs / btrfs / free-space-cache.c

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index c8090f1..1f84fc0 100644 (file)
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1465,10 +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)
@@ -1483,15 +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;
        }
 
@@ -2101,9 +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;
 
@@ -2113,9 +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
@@ -2125,6 +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;
 }