summaryrefslogtreecommitdiffstats
path: root/include/linux/raid/md_p.h
diff options
context:
space:
mode:
authorNeilBrown <neilb@cse.unsw.edu.au>2005-06-21 17:17:27 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-21 19:07:47 -0700
commita654b9d8f851f4ca02649d5825cbe6c608adb10c (patch)
tree747301647f619a9f1dd48f4d6be96b5e35d2484c /include/linux/raid/md_p.h
parent3d310eb7b3df1252e8595d059d982b0a9825a137 (diff)
[PATCH] md: allow md intent bitmap to be stored near the superblock.
This provides an alternate to storing the bitmap in a separate file. The bitmap can be stored at a given offset from the superblock. Obviously the creator of the array must make sure this doesn't intersect with data.... After is good for version-0.90 superblocks. Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/raid/md_p.h')
-rw-r--r--include/linux/raid/md_p.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/raid/md_p.h b/include/linux/raid/md_p.h
index 8ba95d67329..8e592a25a8b 100644
--- a/include/linux/raid/md_p.h
+++ b/include/linux/raid/md_p.h
@@ -96,6 +96,7 @@ typedef struct mdp_device_descriptor_s {
#define MD_SB_CLEAN 0
#define MD_SB_ERRORS 1
+#define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */
typedef struct mdp_superblock_s {
/*
* Constant generic information
@@ -184,7 +185,7 @@ struct mdp_superblock_1 {
/* constant array information - 128 bytes */
__u32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */
__u32 major_version; /* 1 */
- __u32 feature_map; /* 0 for now */
+ __u32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */
__u32 pad0; /* always set to 0 when writing */
__u8 set_uuid[16]; /* user-space generated. */
@@ -197,6 +198,10 @@ struct mdp_superblock_1 {
__u32 chunksize; /* in 512byte sectors */
__u32 raid_disks;
+ __u32 bitmap_offset; /* sectors after start of superblock that bitmap starts
+ * NOTE: signed, so bitmap can be before superblock
+ * only meaningful of feature_map[0] is set.
+ */
__u8 pad1[128-96]; /* set to 0 when written */
/* constant this-device information - 64 bytes */