[PATCH] ext3: add extent map support

On disk extents format:
/*
* this is extent on-disk structure
* it's used at the bottom of the tree
*/
struct ext3_extent {
__le32  ee_block;       /* first logical block extent covers */
__le16  ee_len;         /* number of blocks covered by extent */
__le16  ee_start_hi;    /* high 16 bits of physical block */
__le32  ee_start;       /* low 32 bigs of physical block */
};

Signed-off-by: Alex Tomas <alex@clusterfs.com>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/ext4_fs_i.h b/include/linux/ext4_fs_i.h
index 18a6ce98537f..40ce04a52b04 100644
--- a/include/linux/ext4_fs_i.h
+++ b/include/linux/ext4_fs_i.h
@@ -65,6 +65,16 @@ struct ext4_block_alloc_info {
 #define rsv_end rsv_window._rsv_end
 
 /*
+ * storage for cached extent
+ */
+struct ext4_ext_cache {
+        __u32   ec_start;
+        __u32   ec_block;
+        __u32   ec_len; /* must be 32bit to return holes */
+        __u32   ec_type;
+};
+
+/*
  * third extended file system inode data in memory
  */
 struct ext4_inode_info {
@@ -142,6 +152,9 @@ struct ext4_inode_info {
          */
         struct mutex truncate_mutex;
         struct inode vfs_inode;
+
+        unsigned long i_ext_generation;
+        struct ext4_ext_cache i_cached_extent;
 };
 
 #endif  /* _LINUX_EXT4_FS_I */