[16/19] btrfs: extent-tree: Add new version of btrfs_delalloc_reserve_space

Commit Message

Qu Wenruo Sept. 8, 2015, 9:25 a.m. UTC

Add new version of btrfs_delalloc_reserve_space() function, which
supports accurate qgroup reserve.

Signed-off-by: Qu Wenruo <[e-mail]>
---
 fs/btrfs/ctree.h       |  1 +
 fs/btrfs/extent-tree.c | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

Patch

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index c1a0aaf..12f14fd 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3472,6 +3472,7 @@  void btrfs_subvolume_release_metadata(struct btrfs_root *root,
 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes);
 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes);
 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes);
+int __btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len);
 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes);
 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type);
 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 2e3f19e..07f45b7 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5686,6 +5686,44 @@  void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
 }
 
 /**
+ * __btrfs_delalloc_reserve_space - reserve data and metadata space for
+ * delalloc
+ * @inode: inode we're writing to
+ * @start: start range we are writing to
+ * @len: how long the range we are writing to
+ *
+ * TODO: This function will finally replace old btrfs_delalloc_reserve_space()
+ *
+ * This will do the following things
+ *
+ * o reserve space in data space info for num bytes
+ *   and reserve precious corresponding qgroup space
+ *   (Done in check_data_free_space)
+ *
+ * o reserve space for metadata space, based on the number of outstanding
+ *   extents and how much csums will be needed
+ *   also reserve metadata space in a per root over-reserve method.
+ * o add to the inodes->delalloc_bytes
+ * o add it to the fs_info's delalloc inodes list.
+ *   (Above 3 all done in delalloc_reserve_metadata)
+ *
+ * Return 0 for success
+ * Return <0 for error(-ENOSPC or -EQUOT)
+ */
+int __btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
+{
+	int ret;
+
+	ret = __btrfs_check_data_free_space(inode, start, len);
+	if (ret < 0)
+		return ret;
+	ret = btrfs_delalloc_reserve_metadata(inode, len);
+	if (ret < 0)
+		btrfs_free_reserved_data_space(inode, len);
+	return ret;
+}
+
+/**
  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
  * @inode: inode we're writing to
  * @num_bytes: the number of bytes we want to allocate