[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>

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index f0f510c1341010a06e1c141cf89b5d260246dfdd..c971d38f3a05e4b7b9a96f9710c3a2d4e3e1be36 100644 (file)
--- 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 */