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

Pull btrfs updates from Chris Mason:
 "I held off on my rc5 pull because I hit an oops during log recovery
  after a crash.  I wanted to make sure it wasn't a regression because
  we have some logging fixes in here.

  It turns out that a commit during the merge window just made it much
  more likely to trigger directory logging instead of full commits,
  which exposed an old bug.

  The new backref walking code got some additional fixes.  This should
  be the final set of them.

  Josef fixed up a corner where our O_DIRECT writes and buffered reads
  could expose old file contents (not stale, just not the most recent).
  He and Liu Bo fixed crashes during tree log recover as well.

  Ilya fixed errors while we resume disk balancing operations on
  readonly mounts."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: run delayed directory updates during log replay
  Btrfs: hold a ref on the inode during writepages
  Btrfs: fix tree log remove space corner case
  Btrfs: fix wrong check during log recovery
  Btrfs: use _IOR for BTRFS_IOC_SUBVOL_GETFLAGS
  Btrfs: resume balance on rw (re)mounts properly
  Btrfs: restore restriper state on all mounts
  Btrfs: fix dio write vs buffered read race
  Btrfs: don't count I/O statistic read errors for missing devices
  Btrfs: resolve tree mod log locking issue in btrfs_next_leaf
  Btrfs: fix tree mod log rewind of ADD operations
  Btrfs: leave critical region in btrfs_find_all_roots as soon as possible
  Btrfs: always put insert_ptr modifications into the tree mod log
  Btrfs: fix tree mod log for root replacements at leaf level
  Btrfs: support root level changes in __resolve_indirect_ref
  Btrfs: avoid waiting for delayed refs when we must not

1 files changed, 52 insertions, 93 deletions

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 81296c57405..6c4e2baa929 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1543,29 +1543,26 @@ again:
 	end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
 
 	/*
-	 * XXX - this can go away after a few releases.
-	 *
-	 * since the only user of btrfs_remove_free_space is the tree logging
-	 * stuff, and the only way to test that is under crash conditions, we
-	 * want to have this debug stuff here just in case somethings not
-	 * working.  Search the bitmap for the space we are trying to use to
-	 * make sure its actually there.  If its not there then we need to stop
-	 * because something has gone wrong.
+	 * We need to search for bits in this bitmap.  We could only cover some
+	 * of the extent in this bitmap thanks to how we add space, so we need
+	 * to search for as much as it as we can and clear that amount, and then
+	 * go searching for the next bit.
 	 */
 	search_start = *offset;
-	search_bytes = *bytes;
+	search_bytes = ctl->unit;
 	search_bytes = min(search_bytes, end - search_start + 1);
 	ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
 	BUG_ON(ret < 0 || search_start != *offset);
 
-	if (*offset > bitmap_info->offset && *offset + *bytes > end) {
-		bitmap_clear_bits(ctl, 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(ctl, bitmap_info, *offset, *bytes);
-		*bytes = 0;
-	}
+	/* We may have found more bits than what we need */
+	search_bytes = min(search_bytes, *bytes);
+
+	/* Cannot clear past the end of the bitmap */
+	search_bytes = min(search_bytes, end - search_start + 1);
+
+	bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
+	*offset += search_bytes;
+	*bytes -= search_bytes;
 
 	if (*bytes) {
 		struct rb_node *next = rb_next(&bitmap_info->offset_index);
@@ -1596,7 +1593,7 @@ again:
 		 * everything over again.
 		 */
 		search_start = *offset;
-		search_bytes = *bytes;
+		search_bytes = ctl->unit;
 		ret = search_bitmap(ctl, bitmap_info, &search_start,
 				    &search_bytes);
 		if (ret < 0 || search_start != *offset)
@@ -1879,12 +1876,14 @@ 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;
-	struct btrfs_free_space *next_info = NULL;
 	int ret = 0;
 
 	spin_lock(&ctl->tree_lock);
 
 again:
+	if (!bytes)
+		goto out_lock;
+
 	info = tree_search_offset(ctl, offset, 0, 0);
 	if (!info) {
 		/*
@@ -1905,88 +1904,48 @@ again:
 		}
 	}
 
-	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 * ctl->unit - 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;
-			goto out_lock;
-		}
-
-		info = next_info;
-	}
-
-	if (info->bytes == bytes) {
+	if (!info->bitmap) {
 		unlink_free_space(ctl, info);
-		if (info->bitmap) {
-			kfree(info->bitmap);
-			ctl->total_bitmaps--;
-		}
-		kmem_cache_free(btrfs_free_space_cachep, info);
-		ret = 0;
-		goto out_lock;
-	}
-
-	if (!info->bitmap && info->offset == offset) {
-		unlink_free_space(ctl, info);
-		info->offset += bytes;
-		info->bytes -= bytes;
-		ret = link_free_space(ctl, info);
-		WARN_ON(ret);
-		goto out_lock;
-	}
+		if (offset == info->offset) {
+			u64 to_free = min(bytes, info->bytes);
+
+			info->bytes -= to_free;
+			info->offset += to_free;
+			if (info->bytes) {
+				ret = link_free_space(ctl, info);
+				WARN_ON(ret);
+			} else {
+				kmem_cache_free(btrfs_free_space_cachep, info);
+			}
 
-	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,
-		 * this can happen during tree log replay
-		 *
-		 * first unlink the old info and then
-		 * insert it again after the hole we're creating
-		 */
-		unlink_free_space(ctl, info);
-		if (offset + bytes < info->offset + info->bytes) {
-			u64 old_end = info->offset + info->bytes;
+			offset += to_free;
+			bytes -= to_free;
+			goto again;
+		} else {
+			u64 old_end = info->bytes + info->offset;
 
-			info->offset = offset + bytes;
-			info->bytes = old_end - info->offset;
+			info->bytes = offset - info->offset;
 			ret = link_free_space(ctl, info);
 			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
-			 */
-			kmem_cache_free(btrfs_free_space_cachep, info);
-		}
-		spin_unlock(&ctl->tree_lock);
 
-		/* 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);
-		WARN_ON(ret); /* -ENOMEM */
-		goto out;
+			/* Not enough bytes in this entry to satisfy us */
+			if (old_end < offset + bytes) {
+				bytes -= old_end - offset;
+				offset = old_end;
+				goto again;
+			} else if (old_end == offset + bytes) {
+				/* all done */
+				goto out_lock;
+			}
+			spin_unlock(&ctl->tree_lock);
+
+			ret = btrfs_add_free_space(block_group, offset + bytes,
+						   old_end - (offset + bytes));
+			WARN_ON(ret);
+			goto out;
+		}
 	}
 
 	ret = remove_from_bitmap(ctl, info, &offset, &bytes);