squashfs: add xattr id support

This patch adds support for mapping xattr ids (stored in inodes)
into the on-disk location of the xattrs themselves.

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>

1 files changed, 31 insertions, 1 deletions

diff --git a/fs/squashfs/squashfs_fs.h b/fs/squashfs/squashfs_fs.h
index 79024245ea00..c654e863d3c0 100644
--- a/fs/squashfs/squashfs_fs.h
+++ b/fs/squashfs/squashfs_fs.h
@@ -174,6 +174,24 @@
 
 #define SQUASHFS_ID_BLOCK_BYTES(A)      (SQUASHFS_ID_BLOCKS(A) *\
                                         sizeof(u64))
+/* xattr id lookup table defines */
+#define SQUASHFS_XATTR_BYTES(A)         ((A) * sizeof(struct squashfs_xattr_id))
+
+#define SQUASHFS_XATTR_BLOCK(A)         (SQUASHFS_XATTR_BYTES(A) / \
+                                        SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_XATTR_BLOCK_OFFSET(A)  (SQUASHFS_XATTR_BYTES(A) % \
+                                        SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_XATTR_BLOCKS(A)        ((SQUASHFS_XATTR_BYTES(A) + \
+                                        SQUASHFS_METADATA_SIZE - 1) / \
+                                        SQUASHFS_METADATA_SIZE)
+
+#define SQUASHFS_XATTR_BLOCK_BYTES(A)   (SQUASHFS_XATTR_BLOCKS(A) *\
+                                        sizeof(u64))
+#define SQUASHFS_XATTR_BLK(A)           ((unsigned int) ((A) >> 16))
+
+#define SQUASHFS_XATTR_OFFSET(A)        ((unsigned int) ((A) & 0xffff))
 
 /* cached data constants for filesystem */
 #define SQUASHFS_CACHED_BLKS            8
@@ -228,7 +246,7 @@ struct squashfs_super_block {
         __le64                  root_inode;
         __le64                  bytes_used;
         __le64                  id_table_start;
-        __le64                  xattr_table_start;
+        __le64                  xattr_id_table_start;
         __le64                  inode_table_start;
         __le64                  directory_table_start;
         __le64                  fragment_table_start;
@@ -377,4 +395,16 @@ struct squashfs_fragment_entry {
         unsigned int            unused;
 };
 
+struct squashfs_xattr_id {
+        __le64                  xattr;
+        __le32                  count;
+        __le32                  size;
+};
+
+struct squashfs_xattr_id_table {
+        __le64                  xattr_table_start;
+        __le32                  xattr_ids;
+        __le32                  unused;
+};
+
 #endif