quota: Split off quota tree handling into a separate file

There is going to be a new version of quota format having 64-bit
quota limits and a new quota format for OCFS2. They are both
going to use the same tree structure as VFSv0 quota format. So
split out tree handling into a separate file and make size of
leaf blocks, amount of space usable in each block (needed for
checksumming) and structures contained in them configurable
so that the code can be shared.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/fs/quota_tree.h b/fs/quota_tree.h
new file mode 100644
index 000000000000..a1ab8db81a51
--- /dev/null
+++ b/fs/quota_tree.h
@@ -0,0 +1,25 @@
+/*
+ *      Definitions of structures for vfsv0 quota format
+ */
+
+#ifndef _LINUX_QUOTA_TREE_H
+#define _LINUX_QUOTA_TREE_H
+
+#include <linux/types.h>
+#include <linux/quota.h>
+
+/*
+ *  Structure of header of block with quota structures. It is padded to 16 bytes so
+ *  there will be space for exactly 21 quota-entries in a block
+ */
+struct qt_disk_dqdbheader {
+        __le32 dqdh_next_free;  /* Number of next block with free entry */
+        __le32 dqdh_prev_free;  /* Number of previous block with free entry */
+        __le16 dqdh_entries;    /* Number of valid entries in block */
+        __le16 dqdh_pad1;
+        __le32 dqdh_pad2;
+};
+
+#define QT_TREEOFF      1               /* Offset of tree in file in blocks */
+
+#endif /* _LINUX_QUOTAIO_TREE_H */