1 files changed, 37 insertions, 5 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 99e0ae1a4c78..b3c1efff5e1d 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -285,6 +285,8 @@ static void init_once(void *foo)
         INIT_LIST_HEAD(&bdev->bd_holder_list);
 #endif
         inode_init_once(&ei->vfs_inode);
+        /* Initialize mutex for freeze. */
+        mutex_init(&bdev->bd_fsfreeze_mutex);
 }
 
 static inline void __bd_forget(struct inode *inode)
@@ -326,12 +328,13 @@ static struct file_system_type bd_type = {
         .kill_sb        = kill_anon_super,
 };
 
-static struct vfsmount *bd_mnt __read_mostly;
-struct super_block *blockdev_superblock;
+struct super_block *blockdev_superblock __read_mostly;
 
 void __init bdev_cache_init(void)
 {
         int err;
+        struct vfsmount *bd_mnt;
+
         bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
                         0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
                                 SLAB_MEM_SPREAD|SLAB_PANIC),
@@ -373,7 +376,7 @@ struct block_device *bdget(dev_t dev)
         struct block_device *bdev;
         struct inode *inode;
 
-        inode = iget5_locked(bd_mnt->mnt_sb, hash(dev),
+        inode = iget5_locked(blockdev_superblock, hash(dev),
                         bdev_test, bdev_set, &dev);
 
         if (!inode)
@@ -463,7 +466,7 @@ void bd_forget(struct inode *inode)
 
         spin_lock(&bdev_lock);
         if (inode->i_bdev) {
-                if (inode->i_sb != blockdev_superblock)
+                if (!sb_is_blkdev_sb(inode->i_sb))
                         bdev = inode->i_bdev;
                 __bd_forget(inode);
         }
@@ -1004,6 +1007,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
         }
 
         lock_kernel();
+ restart:
 
         ret = -ENXIO;
         disk = get_gendisk(bdev->bd_dev, &partno);
@@ -1024,6 +1028,19 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 
                         if (disk->fops->open) {
                                 ret = disk->fops->open(bdev, mode);
+                                if (ret == -ERESTARTSYS) {
+                                        /* Lost a race with 'disk' being
+                                         * deleted, try again.
+                                         * See md.c
+                                         */
+                                        disk_put_part(bdev->bd_part);
+                                        bdev->bd_part = NULL;
+                                        module_put(disk->fops->owner);
+                                        put_disk(disk);
+                                        bdev->bd_disk = NULL;
+                                        mutex_unlock(&bdev->bd_mutex);
+                                        goto restart;
+                                }
                                 if (ret)
                                         goto out_clear;
                         }
@@ -1219,6 +1236,20 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
         return blkdev_ioctl(bdev, mode, cmd, arg);
 }
 
+/*
+ * Try to release a page associated with block device when the system
+ * is under memory pressure.
+ */
+static int blkdev_releasepage(struct page *page, gfp_t wait)
+{
+        struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super;
+
+        if (super && super->s_op->bdev_try_to_free_page)
+                return super->s_op->bdev_try_to_free_page(super, page, wait);
+
+        return try_to_free_buffers(page);
+}
+
 static const struct address_space_operations def_blk_aops = {
         .readpage       = blkdev_readpage,
         .writepage      = blkdev_writepage,
@@ -1226,6 +1257,7 @@ static const struct address_space_operations def_blk_aops = {
         .write_begin    = blkdev_write_begin,
         .write_end      = blkdev_write_end,
         .writepages     = generic_writepages,
+        .releasepage    = blkdev_releasepage,
         .direct_IO      = blkdev_direct_IO,
 };
 
@@ -1261,7 +1293,7 @@ EXPORT_SYMBOL(ioctl_by_bdev);
 
 /**
  * lookup_bdev  - lookup a struct block_device by name
- * @path:       special file representing the block device
+ * @pathname:   special file representing the block device
  *
  * Get a reference to the blockdevice at @pathname in the current
  * namespace if possible and return it.  Return ERR_PTR(error)