[PATCH] md: all hot-add and hot-remove of md intent logging bitmaps

Both file-bitmaps and superblock bitmaps are supported.

If you add a bitmap file on the array device, you lose.

This introduces a 'default_bitmap_offset' field in mddev, as the ioctl used
for adding a superblock bitmap doesn't have room for giving an offset.  Later,
this value will be setable via sysfs.

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>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 63c5661..ae65446 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -623,6 +623,7 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                mddev->size = sb->size;
                mddev->events = md_event(sb);
                mddev->bitmap_offset = 0;
+               mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
 
                if (sb->state & (1<<MD_SB_CLEAN))
                        mddev->recovery_cp = MaxSector;
@@ -648,7 +649,7 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                                printk(KERN_WARNING "md: bitmaps only support for raid1\n");
                                return -EINVAL;
                        }
-                       mddev->bitmap_offset = (MD_SB_BYTES >> 9);
+                       mddev->bitmap_offset = mddev->default_bitmap_offset;
                }
 
        } else if (mddev->pers == NULL) {
@@ -939,6 +940,9 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
                mddev->size = le64_to_cpu(sb->size)/2;
                mddev->events = le64_to_cpu(sb->events);
                mddev->bitmap_offset = 0;
+               mddev->default_bitmap_offset = 0;
+               if (mddev->minor_version == 0)
+                       mddev->default_bitmap_offset = -(64*1024)/512;
                
                mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
                memcpy(mddev->uuid, sb->set_uuid, 16);
@@ -2073,6 +2077,8 @@ static int get_array_info(mddev_t * mddev, void __user * arg)
        info.state         = 0;
        if (mddev->in_sync)
                info.state = (1<<MD_SB_CLEAN);
+       if (mddev->bitmap && mddev->bitmap_offset)
+               info.state = (1<<MD_SB_BITMAP_PRESENT);
        info.active_disks  = active;
        info.working_disks = working;
        info.failed_disks  = failed;
@@ -2430,25 +2436,51 @@ static int set_bitmap_file(mddev_t *mddev, int fd)
 {
        int err;
 
-       if (mddev->pers || mddev->bitmap_file)
-               return -EBUSY;
+       if (mddev->pers) {
+               if (!mddev->pers->quiesce)
+                       return -EBUSY;
+               if (mddev->recovery || mddev->sync_thread)
+                       return -EBUSY;
+               /* we should be able to change the bitmap.. */
+       }
 
-       mddev->bitmap_file = fget(fd);
 
-       if (mddev->bitmap_file == NULL) {
-               printk(KERN_ERR "%s: error: failed to get bitmap file\n",
-                       mdname(mddev));
-               return -EBADF;
-       }
+       if (fd >= 0) {
+               if (mddev->bitmap)
+                       return -EEXIST; /* cannot add when bitmap is present */
+               mddev->bitmap_file = fget(fd);
 
-       err = deny_bitmap_write_access(mddev->bitmap_file);
-       if (err) {
-               printk(KERN_ERR "%s: error: bitmap file is already in use\n",
-                       mdname(mddev));
-               fput(mddev->bitmap_file);
-               mddev->bitmap_file = NULL;
-       } else
+               if (mddev->bitmap_file == NULL) {
+                       printk(KERN_ERR "%s: error: failed to get bitmap file\n",
+                              mdname(mddev));
+                       return -EBADF;
+               }
+
+               err = deny_bitmap_write_access(mddev->bitmap_file);
+               if (err) {
+                       printk(KERN_ERR "%s: error: bitmap file is already in use\n",
+                              mdname(mddev));
+                       fput(mddev->bitmap_file);
+                       mddev->bitmap_file = NULL;
+                       return err;
+               }
                mddev->bitmap_offset = 0; /* file overrides offset */
+       } else if (mddev->bitmap == NULL)
+               return -ENOENT; /* cannot remove what isn't there */
+       err = 0;
+       if (mddev->pers) {
+               mddev->pers->quiesce(mddev, 1);
+               if (fd >= 0)
+                       err = bitmap_create(mddev);
+               if (fd < 0 || err)
+                       bitmap_destroy(mddev);
+               mddev->pers->quiesce(mddev, 0);
+       } else if (fd < 0) {
+               if (mddev->bitmap_file)
+                       fput(mddev->bitmap_file);
+               mddev->bitmap_file = NULL;
+       }
+
        return err;
 }
 
@@ -2528,6 +2560,11 @@ static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
 {
        int rv = 0;
        int cnt = 0;
+       int state = 0;
+
+       /* calculate expected state,ignoring low bits */
+       if (mddev->bitmap && mddev->bitmap_offset)
+               state |= (1 << MD_SB_BITMAP_PRESENT);
 
        if (mddev->major_version != info->major_version ||
            mddev->minor_version != info->minor_version ||
@@ -2536,12 +2573,16 @@ static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
            mddev->level         != info->level         ||
 /*         mddev->layout        != info->layout        || */
            !mddev->persistent   != info->not_persistent||
-           mddev->chunk_size    != info->chunk_size    )
+           mddev->chunk_size    != info->chunk_size    ||
+           /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
+           ((state^info->state) & 0xfffffe00)
+               )
                return -EINVAL;
        /* Check there is only one change */
        if (mddev->size != info->size) cnt++;
        if (mddev->raid_disks != info->raid_disks) cnt++;
        if (mddev->layout != info->layout) cnt++;
+       if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) cnt++;
        if (cnt == 0) return 0;
        if (cnt > 1) return -EINVAL;
 
@@ -2620,6 +2661,35 @@ static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
                        }
                }
        }
+       if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) {
+               if (mddev->pers->quiesce == NULL)
+                       return -EINVAL;
+               if (mddev->recovery || mddev->sync_thread)
+                       return -EBUSY;
+               if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
+                       /* add the bitmap */
+                       if (mddev->bitmap)
+                               return -EEXIST;
+                       if (mddev->default_bitmap_offset == 0)
+                               return -EINVAL;
+                       mddev->bitmap_offset = mddev->default_bitmap_offset;
+                       mddev->pers->quiesce(mddev, 1);
+                       rv = bitmap_create(mddev);
+                       if (rv)
+                               bitmap_destroy(mddev);
+                       mddev->pers->quiesce(mddev, 0);
+               } else {
+                       /* remove the bitmap */
+                       if (!mddev->bitmap)
+                               return -ENOENT;
+                       if (mddev->bitmap->file)
+                               return -EINVAL;
+                       mddev->pers->quiesce(mddev, 1);
+                       bitmap_destroy(mddev);
+                       mddev->pers->quiesce(mddev, 0);
+                       mddev->bitmap_offset = 0;
+               }
+       }
        md_update_sb(mddev);
        return rv;
 }

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index ace41c5..ba643e4 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1565,6 +1565,35 @@ static int raid1_reshape(mddev_t *mddev, int raid_disks)
        return 0;
 }
 
+void raid1_quiesce(mddev_t *mddev, int state)
+{
+       conf_t *conf = mddev_to_conf(mddev);
+
+       switch(state) {
+       case 0:
+               spin_lock_irq(&conf->resync_lock);
+               conf->barrier++;
+               wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
+                                   conf->resync_lock, raid1_unplug(mddev->queue));
+               spin_unlock_irq(&conf->resync_lock);
+               break;
+       case 1:
+               spin_lock_irq(&conf->resync_lock);
+               conf->barrier--;
+               spin_unlock_irq(&conf->resync_lock);
+               wake_up(&conf->wait_resume);
+               wake_up(&conf->wait_idle);
+               break;
+       }
+       if (mddev->thread) {
+               if (mddev->bitmap)
+                       mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
+               else
+                       mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
+               md_wakeup_thread(mddev->thread);
+       }
+}
+
 
 static mdk_personality_t raid1_personality =
 {
@@ -1581,6 +1610,7 @@ static mdk_personality_t raid1_personality =
        .sync_request   = sync_request,
        .resize         = raid1_resize,
        .reshape        = raid1_reshape,
+       .quiesce        = raid1_quiesce,
 };
 
 static int __init raid_init(void)

diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index 8c14ba5..817062b 100644 (file)
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -278,6 +278,10 @@ struct mddev_s
                                                        * start of bitmap. May be
                                                        * negative, but not '0'
                                                        */
+       long                            default_bitmap_offset; /* this is the offset to use when
+                                                               * hot-adding a bitmap.  It should
+                                                               * eventually be settable by sysfs.
+                                                               */
 
        struct list_head                all_mddevs;
 };
@@ -314,6 +318,12 @@ struct mdk_personality_s
        int (*resize) (mddev_t *mddev, sector_t sectors);
        int (*reshape) (mddev_t *mddev, int raid_disks);
        int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
+       /* quiesce moves between quiescence states
+        * 0 - fully active
+        * 1 - no new requests allowed
+        * others - reserved
+        */
+       void (*quiesce) (mddev_t *mddev, int state);
 };