[PATCH 1/2] block: Set inode of block_device size to zero when delete gendisk.

[majianpeng <majianpeng@gmail.com>]

When remove gendisk, set the size of inode of block_device to zero.
This is mainly let the vfs know disk removed.

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
---
 block/genhd.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/block/genhd.c b/block/genhd.c
index dadf42b..c3a54b4 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -634,6 +634,7 @@ void del_gendisk(struct gendisk *disk)
 {
 	struct disk_part_iter piter;
 	struct hd_struct *part;
+	struct block_device *bdev;
 
 	disk_del_events(disk);
 
@@ -655,6 +656,19 @@ void del_gendisk(struct gendisk *disk)
 	blk_unregister_queue(disk);
 	blk_unregister_region(disk_devt(disk), disk->minors);
 
+	/*
+	 * When used buffer-mode on raw blockdevice,the disk removed.
+	 * But the vfs don't know.So tell the vfs size of disk became zero,
+	 * the buffer write  can return
+	 */
+	bdev = bdget_disk(disk, 0);
+	if (bdev) {
+		mutex_lock(&bdev->bd_inode->i_mutex);
+		i_size_write(bdev->bd_inode, 0);
+		mutex_unlock(&bdev->bd_inode->i_mutex);
+		bdput(bdev);
+	}
+
 	part_stat_set_all(&disk->part0, 0);
 	disk->part0.stamp = 0;
 
-- 
1.8.4-rc0