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authorNeilBrown <neilb@cse.unsw.edu.au>2005-06-21 20:17:14 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-21 22:07:43 -0400
commit32a7627cf3a35396a8e834faf34e38ae9f3b1309 (patch)
tree3fe7764f5d8e39d835a397e1099358d924b02981 /include/linux/raid/md_k.h
parent57afd89f98a990747445f01c458ecae64263b2f8 (diff)
[PATCH] md: optimised resync using Bitmap based intent logging
With this patch, the intent to write to some block in the array can be logged to a bitmap file. Each bit represents some number of sectors and is set before any update happens, and only cleared when all writes relating to all sectors are complete. After an unclean shutdown, information in this bitmap can be used to optimise resync - only sectors which could be out-of-sync need to be updated. Also if a drive is removed and then added back into an array, the recovery can make use of the bitmap to optimise reconstruction. This is not implemented in this patch. Currently the bitmap is stored in a file which must (obviously) be stored on a separate device. The patch only provided infrastructure. It does not update any personalities to bitmap intent logging. Md arrays can still be used with no bitmap file. This patch has minimal impact on such arrays. 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_k.h')
-rw-r--r--include/linux/raid/md_k.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index bce0032decf..16e94a9f0f8 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -267,6 +267,9 @@ struct mddev_s
267 atomic_t writes_pending; 267 atomic_t writes_pending;
268 request_queue_t *queue; /* for plugging ... */ 268 request_queue_t *queue; /* for plugging ... */
269 269
270 struct bitmap *bitmap; /* the bitmap for the device */
271 struct file *bitmap_file; /* the bitmap file */
272
270 struct list_head all_mddevs; 273 struct list_head all_mddevs;
271}; 274};
272 275
@@ -341,6 +344,7 @@ typedef struct mdk_thread_s {
341 unsigned long flags; 344 unsigned long flags;
342 struct completion *event; 345 struct completion *event;
343 struct task_struct *tsk; 346 struct task_struct *tsk;
347 unsigned long timeout;
344 const char *name; 348 const char *name;
345} mdk_thread_t; 349} mdk_thread_t;
346 350