From: Zheng Liu <wenqing.lz@xxxxxxxxxx>
es_pblk is used to record physical block that maps to the disk.
es_status is used to record the status of the extent. Three status
are defined, which are written, unwritten and delayed.
Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
---
fs/ext4/extents_status.h | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index 81e9339..2eb9cc3 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -20,10 +20,22 @@
#define es_debug(fmt, ...) no_printk(fmt, ##__VA_ARGS__)
#endif
+enum {
+ EXTENT_STATUS_WRITTEN = 0, /* written extent */
+ EXTENT_STATUS_UNWRITTEN = 1, /* unwritten extent */
+ EXTENT_STATUS_DELAYED = 2, /* delayed extent */
+};
+
+/*
+ * Here for save memory es_status is stashed into es_pblk because we only have
+ * 48 bits physical block and es_status only needs 2 bits.
+ */
struct extent_status {
struct rb_node rb_node;
- ext4_lblk_t es_lblk; /* first logical block extent covers */
- ext4_lblk_t es_len; /* length of extent in block */
+ ext4_lblk_t es_lblk; /* first logical block extent covers */
+ ext4_lblk_t es_len; /* length of extent in block */
+ ext4_fsblk_t es_pblk : 62; /* first physical block */
+ ext4_fsblk_t es_status : 2; /* record the status of extent */
};
struct ext4_es_tree {
--
1.7.12.rc2.18.g61b472e
--
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