btrfs: qgroup: Introduce btrfs_qgroup_reserve_data function

Introduce a new function, btrfs_qgroup_reserve_data(), which will use
io_tree to accurate qgroup reserve, to avoid reserved space leaking.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 51e1b71..f4c1ae1 100644 (file)
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -19,6 +19,7 @@
 #define EXTENT_NEED_WAIT       (1U << 13)
 #define EXTENT_DAMAGED         (1U << 14)
 #define EXTENT_NORESERVE       (1U << 15)
+#define EXTENT_QGROUP_RESERVED (1U << 16)
 #define EXTENT_IOBITS          (EXTENT_LOCKED | EXTENT_WRITEBACK)
 #define EXTENT_CTLBITS         (EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC)
 

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index d904ee1..5066274 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2486,3 +2486,52 @@ btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
                btrfs_queue_work(fs_info->qgroup_rescan_workers,
                                 &fs_info->qgroup_rescan_work);
 }
+
+/*
+ * Reserve qgroup space for range [start, start + len).
+ *
+ * This function will either reserve space from related qgroups or doing
+ * nothing if the range is already reserved.
+ *
+ * Return 0 for successful reserve
+ * Return <0 for error (including -EQUOT)
+ *
+ * NOTE: this function may sleep for memory allocation.
+ */
+int btrfs_qgroup_reserve_data(struct inode *inode, u64 start, u64 len)
+{
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+       struct extent_changeset changeset;
+       struct ulist_node *unode;
+       struct ulist_iterator uiter;
+       int ret;
+
+       if (!root->fs_info->quota_enabled || !is_fstree(root->objectid) ||
+           len == 0)
+               return 0;
+
+       changeset.bytes_changed = 0;
+       changeset.range_changed = ulist_alloc(GFP_NOFS);
+
+       ret = set_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
+                       start + len -1, EXTENT_QGROUP_RESERVED, GFP_NOFS,
+                       &changeset);
+       if (ret < 0)
+               goto cleanup;
+       ret = btrfs_qgroup_reserve(root, changeset.bytes_changed);
+       if (ret < 0)
+               goto cleanup;
+
+       ulist_free(changeset.range_changed);
+       return ret;
+
+cleanup:
+       /* cleanup already reserved ranges */
+       ULIST_ITER_INIT(&uiter);
+       while ((unode = ulist_next(changeset.range_changed, &uiter)))
+               clear_extent_bit(&BTRFS_I(inode)->io_tree, unode->val,
+                                unode->aux, EXTENT_QGROUP_RESERVED, 0, 0, NULL,
+                                GFP_NOFS);
+       ulist_free(changeset.range_changed);
+       return ret;
+}

diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index 6387dcf..bd17cc2 100644 (file)
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -81,4 +81,6 @@ int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
                               u64 rfer, u64 excl);
 #endif
 
+/* New io_tree based accurate qgroup reserve API */
+int btrfs_qgroup_reserve_data(struct inode *inode, u64 start, u64 len);
 #endif /* __BTRFS_QGROUP__ */