From 32a7627cf3a35396a8e834faf34e38ae9f3b1309 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 21 Jun 2005 17:17:14 -0700 Subject: [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/raid/md_k.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/raid/md_k.h') 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 atomic_t writes_pending; request_queue_t *queue; /* for plugging ... */ + struct bitmap *bitmap; /* the bitmap for the device */ + struct file *bitmap_file; /* the bitmap file */ + struct list_head all_mddevs; }; @@ -341,6 +344,7 @@ typedef struct mdk_thread_s { unsigned long flags; struct completion *event; struct task_struct *tsk; + unsigned long timeout; const char *name; } mdk_thread_t; -- cgit v1.2.3