Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs update from Chris Mason:
 "The biggest feature in the pull is the new (and still experimental)
  raid56 code that David Woodhouse started long ago.  I'm still working
  on the parity logging setup that will avoid inconsistent parity after
  a crash, so this is only for testing right now.  But, I'd really like
  to get it out to a broader audience to hammer out any performance
  issues or other problems.

  scrub does not yet correct errors on raid5/6 either.

  Josef has another pass at fsync performance.  The big change here is
  to combine waiting for metadata with waiting for data, which is a big
  latency win.  It is also step one toward using atomics from the
  hardware during a commit.

  Mark Fasheh has a new way to use btrfs send/receive to send only the
  metadata changes.  SUSE is using this to make snapper more efficient
  at finding changes between snapshosts.

  Snapshot-aware defrag is also included.

  Otherwise we have a large number of fixes and cleanups.  Eric Sandeen
  wins the award for removing the most lines, and I'm hoping we steal
  this idea from XFS over and over again."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (118 commits)
  btrfs: fixup/remove module.h usage as required
  Btrfs: delete inline extents when we find them during logging
  btrfs: try harder to allocate raid56 stripe cache
  Btrfs: cleanup to make the function btrfs_delalloc_reserve_metadata more logic
  Btrfs: don't call btrfs_qgroup_free if just btrfs_qgroup_reserve fails
  Btrfs: remove reduplicate check about root in the function btrfs_clean_quota_tree
  Btrfs: return ENOMEM rather than use BUG_ON when btrfs_alloc_path fails
  Btrfs: fix missing deleted items in btrfs_clean_quota_tree
  btrfs: use only inline_pages from extent buffer
  Btrfs: fix wrong reserved space when deleting a snapshot/subvolume
  Btrfs: fix wrong reserved space in qgroup during snap/subv creation
  Btrfs: remove unnecessary dget_parent/dput when creating the pending snapshot
  btrfs: remove a printk from scan_one_device
  Btrfs: fix NULL pointer after aborting a transaction
  Btrfs: fix memory leak of log roots
  Btrfs: copy everything if we've created an inline extent
  btrfs: cleanup for open-coded alignment
  Btrfs: do not change inode flags in rename
  Btrfs: use reserved space for creating a snapshot
  clear chunk_alloc flag on retryable failure
  ...

1 files changed, 51 insertions, 11 deletions

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 0be7a8742a43..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;
@@ -2095,9 +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;
 
@@ -2107,9 +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
@@ -2119,6 +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;
 }