bcache: Fix bcache device claiming

[linux-2.6-block.git] / drivers / md / bcache / super.c

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 913dd94353b662bc8f4cdebf3a5acb1b9127dc7d..0ae2b3676293074a1621226ceee76f0cac6b5d63 100644 (file)
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1369,7 +1369,7 @@ static void cached_dev_free(struct closure *cl)
                put_page(virt_to_page(dc->sb_disk));
 
        if (!IS_ERR_OR_NULL(dc->bdev))
-               blkdev_put(dc->bdev, bcache_kobj);
+               blkdev_put(dc->bdev, dc);
 
        wake_up(&unregister_wait);
 
@@ -1453,7 +1453,6 @@ static int register_bdev(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 
        memcpy(&dc->sb, sb, sizeof(struct cache_sb));
        dc->bdev = bdev;
-       dc->bdev->bd_holder = dc;
        dc->sb_disk = sb_disk;
 
        if (cached_dev_init(dc, sb->block_size << 9))
@@ -2218,7 +2217,7 @@ void bch_cache_release(struct kobject *kobj)
                put_page(virt_to_page(ca->sb_disk));
 
        if (!IS_ERR_OR_NULL(ca->bdev))
-               blkdev_put(ca->bdev, bcache_kobj);
+               blkdev_put(ca->bdev, ca);
 
        kfree(ca);
        module_put(THIS_MODULE);
@@ -2345,7 +2344,6 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
 
        memcpy(&ca->sb, sb, sizeof(struct cache_sb));
        ca->bdev = bdev;
-       ca->bdev->bd_holder = ca;
        ca->sb_disk = sb_disk;
 
        if (bdev_max_discard_sectors((bdev)))
@@ -2359,7 +2357,7 @@ static int register_cache(struct cache_sb *sb, struct cache_sb_disk *sb_disk,
                 * call blkdev_put() to bdev in bch_cache_release(). So we
                 * explicitly call blkdev_put() here.
                 */
-               blkdev_put(bdev, bcache_kobj);
+               blkdev_put(bdev, ca);
                if (ret == -ENOMEM)
                        err = "cache_alloc(): -ENOMEM";
                else if (ret == -EPERM)
@@ -2516,10 +2514,11 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
        char *path = NULL;
        struct cache_sb *sb;
        struct cache_sb_disk *sb_disk;
-       struct block_device *bdev;
-       void *holder;
+       struct block_device *bdev, *bdev2;
+       void *holder = NULL;
        ssize_t ret;
        bool async_registration = false;
+       bool quiet = false;
 
 #ifdef CONFIG_BCACHE_ASYNC_REGISTRATION
        async_registration = true;
@@ -2548,24 +2547,9 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
 
        ret = -EINVAL;
        err = "failed to open device";
-       bdev = blkdev_get_by_path(strim(path), BLK_OPEN_READ | BLK_OPEN_WRITE,
-                                 bcache_kobj, NULL);
-       if (IS_ERR(bdev)) {
-               if (bdev == ERR_PTR(-EBUSY)) {
-                       dev_t dev;
-
-                       mutex_lock(&bch_register_lock);
-                       if (lookup_bdev(strim(path), &dev) == 0 &&
-                           bch_is_open(dev))
-                               err = "device already registered";
-                       else
-                               err = "device busy";
-                       mutex_unlock(&bch_register_lock);
-                       if (attr == &ksysfs_register_quiet)
-                               goto done;
-               }
+       bdev = blkdev_get_by_path(strim(path), BLK_OPEN_READ, NULL, NULL);
+       if (IS_ERR(bdev))
                goto out_free_sb;
-       }
 
        err = "failed to set blocksize";
        if (set_blocksize(bdev, 4096))
@@ -2582,6 +2566,32 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
                goto out_put_sb_page;
        }
 
+       /* Now reopen in exclusive mode with proper holder */
+       bdev2 = blkdev_get_by_dev(bdev->bd_dev, BLK_OPEN_READ | BLK_OPEN_WRITE,
+                                 holder, NULL);
+       blkdev_put(bdev, NULL);
+       bdev = bdev2;
+       if (IS_ERR(bdev)) {
+               ret = PTR_ERR(bdev);
+               bdev = NULL;
+               if (ret == -EBUSY) {
+                       dev_t dev;
+
+                       mutex_lock(&bch_register_lock);
+                       if (lookup_bdev(strim(path), &dev) == 0 &&
+                           bch_is_open(dev))
+                               err = "device already registered";
+                       else
+                               err = "device busy";
+                       mutex_unlock(&bch_register_lock);
+                       if (attr == &ksysfs_register_quiet) {
+                               quiet = true;
+                               ret = size;
+                       }
+               }
+               goto out_free_holder;
+       }
+
        err = "failed to register device";
 
        if (async_registration) {
@@ -2619,7 +2629,6 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
                        goto out_free_sb;
        }
 
-done:
        kfree(sb);
        kfree(path);
        module_put(THIS_MODULE);
@@ -2631,7 +2640,8 @@ out_free_holder:
 out_put_sb_page:
        put_page(virt_to_page(sb_disk));
 out_blkdev_put:
-       blkdev_put(bdev, register_bcache);
+       if (bdev)
+               blkdev_put(bdev, holder);
 out_free_sb:
        kfree(sb);
 out_free_path:
@@ -2640,7 +2650,8 @@ out_free_path:
 out_module_put:
        module_put(THIS_MODULE);
 out:
-       pr_info("error %s: %s\n", path?path:"", err);
+       if (!quiet)
+               pr_info("error %s: %s\n", path?path:"", err);
        return ret;
 }