[PATCH] md: allow dirty raid[456] arrays to be started at boot

See patch to md.txt for more details

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 24 insertions, 8 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8175a2a222da..b4fb7247b3ed 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1937,6 +1937,7 @@ static void md_safemode_timeout(unsigned long data)
         md_wakeup_thread(mddev->thread);
 }
 
+static int start_dirty_degraded;
 
 static int do_md_run(mddev_t * mddev)
 {
@@ -2048,6 +2049,7 @@ static int do_md_run(mddev_t * mddev)
         mddev->recovery = 0;
         mddev->resync_max_sectors = mddev->size << 1; /* may be over-ridden by personality */
         mddev->barriers_work = 1;
+        mddev->ok_start_degraded = start_dirty_degraded;
 
         if (start_readonly)
                 mddev->ro = 2; /* read-only, but switch on first write */
@@ -4509,6 +4511,8 @@ static int set_ro(const char *val, struct kernel_param *kp)
 }
 
 module_param_call(start_ro, set_ro, get_ro, NULL, 0600);
+module_param(start_dirty_degraded, int, 0644);
+
 
 EXPORT_SYMBOL(register_md_personality);
 EXPORT_SYMBOL(unregister_md_personality);
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 334ff7a07283..53a0f2ce76c8 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1904,10 +1904,17 @@ static int run(mddev_t *mddev)
 
         if (mddev->degraded == 1 &&
             mddev->recovery_cp != MaxSector) {
-                printk(KERN_ERR 
-                        "raid5: cannot start dirty degraded array for %s\n",
-                        mdname(mddev));
-                goto abort;
+                if (mddev->ok_start_degraded)
+                        printk(KERN_WARNING
+                               "raid5: starting dirty degraded array: %s"
+                               "- data corruption possible.\n",
+                               mdname(mddev));
+                else {
+                        printk(KERN_ERR
+                               "raid5: cannot start dirty degraded array for %s\n",
+                               mdname(mddev));
+                        goto abort;
+                }
         }
 
         {
diff --git a/drivers/md/raid6main.c b/drivers/md/raid6main.c
index 0000d162d198..9ac6dcd55127 100644
--- a/drivers/md/raid6main.c
+++ b/drivers/md/raid6main.c
@@ -1929,13 +1929,18 @@ static int run(mddev_t *mddev)
                 goto abort;
         }
 
-#if 0                           /* FIX: For now */
         if (mddev->degraded > 0 &&
             mddev->recovery_cp != MaxSector) {
-                printk(KERN_ERR "raid6: cannot start dirty degraded array for %s\n", mdname(mddev));
-                goto abort;
+                if (mddev->ok_start_degraded)
+                        printk(KERN_WARNING "raid6: starting dirty degraded array:%s"
+                               "- data corruption possible.\n",
+                               mdname(mddev));
+                else {
+                        printk(KERN_ERR "raid6: cannot start dirty degraded array"
+                               " for %s\n", mdname(mddev));
+                        goto abort;
+                }
         }
-#endif
 
         {
                 mddev->thread = md_register_thread(raid6d, mddev, "%s_raid6");