[PATCH] md: do not set mddev->bitmap until bitmap is fully initialised

When hot-adding a bitmap, bitmap_daemon_work could get called while the bitmap
is being created, so don't set mddev->bitmap until the bitmap is ready.

This requires freeing the bitmap inside bitmap_create if creation failed
part-way through.

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>

1 files changed, 24 insertions, 9 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index f0f510c13410..c971d38f3a05 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1503,17 +1503,14 @@ void bitmap_flush(mddev_t *mddev)
 /*
  * free memory that was allocated
  */
-void bitmap_destroy(mddev_t *mddev)
+static void bitmap_free(struct bitmap *bitmap)
 {
         unsigned long k, pages;
         struct bitmap_page *bp;
-        struct bitmap *bitmap = mddev->bitmap;
 
         if (!bitmap) /* there was no bitmap */
                 return;
 
-        mddev->bitmap = NULL; /* disconnect from the md device */
-
         /* release the bitmap file and kill the daemon */
         bitmap_file_put(bitmap);
 
@@ -1531,6 +1528,17 @@ void bitmap_destroy(mddev_t *mddev)
         kfree(bp);
         kfree(bitmap);
 }
+void bitmap_destroy(mddev_t *mddev)
+{
+        struct bitmap *bitmap = mddev->bitmap;
+
+        if (!bitmap) /* there was no bitmap */
+                return;
+
+        mddev->bitmap = NULL; /* disconnect from the md device */
+
+        bitmap_free(bitmap);
+}
 
 /*
  * initialize the bitmap structure
@@ -1561,15 +1569,15 @@ int bitmap_create(mddev_t *mddev)
 
         spin_lock_init(&bitmap->lock);
         bitmap->mddev = mddev;
-        mddev->bitmap = bitmap;
 
         spin_lock_init(&bitmap->write_lock);
         INIT_LIST_HEAD(&bitmap->complete_pages);
         init_waitqueue_head(&bitmap->write_wait);
         bitmap->write_pool = mempool_create(WRITE_POOL_SIZE, write_pool_alloc,
                                 write_pool_free, NULL);
+        err = -ENOMEM;
         if (!bitmap->write_pool)
-                return -ENOMEM;
+                goto error;
 
         bitmap->file = file;
         bitmap->offset = mddev->bitmap_offset;
@@ -1577,7 +1585,7 @@ int bitmap_create(mddev_t *mddev)
         /* read superblock from bitmap file (this sets bitmap->chunksize) */
         err = bitmap_read_sb(bitmap);
         if (err)
-                return err;
+                goto error;
 
         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
                                         sizeof(bitmap->chunksize));
@@ -1601,8 +1609,9 @@ int bitmap_create(mddev_t *mddev)
 #else
         bitmap->bp = kmalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
 #endif
+        err = -ENOMEM;
         if (!bitmap->bp)
-                return -ENOMEM;
+                goto error;
         memset(bitmap->bp, 0, pages * sizeof(*bitmap->bp));
 
         bitmap->flags |= BITMAP_ACTIVE;
@@ -1617,16 +1626,22 @@ int bitmap_create(mddev_t *mddev)
         err = bitmap_init_from_disk(bitmap, start);
 
         if (err)
-                return err;
+                goto error;
 
         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
                 pages, bmname(bitmap));
 
+        mddev->bitmap = bitmap;
+
         /* kick off the bitmap daemons */
         err = bitmap_start_daemons(bitmap);
         if (err)
                 return err;
         return bitmap_update_sb(bitmap);
+
+ error:
+        bitmap_free(bitmap);
+        return err;
 }
 
 /* the bitmap API -- for raid personalities */