From 3fef7d561ee71307945f7e31980581eec93da55c Mon Sep 17 00:00:00 2001
From: Andrew Patterson <andrew.patterson@hp.com>
Date: Thu, 4 Sep 2008 14:27:25 -0600
Subject: [PATCH] --- yaml --- r: 110519 b: refs/heads/master c:
 c3279d1454cdfed02a557d789d8a6d08ab4cbe70 h: refs/heads/master i:   110517:
 5f865251cf541db5ec0d6606e7bf8a05cc1632f6   110515:
 744ed94d86977a8e29abe02fed212d9f272216ae   110511:
 da5a10c74efa5026efcb2192e021166320335f91 v: v3

---
 [refs]                   |  2 +-
 trunk/fs/block_dev.c     | 37 +++++++++++++++++++++++++++++++++++++
 trunk/include/linux/fs.h |  2 ++
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 736e44a71258..49897873a9c6 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0c002c2f74e10baa9021d3ecc50585c6eafea568
+refs/heads/master: c3279d1454cdfed02a557d789d8a6d08ab4cbe70
diff --git a/trunk/fs/block_dev.c b/trunk/fs/block_dev.c
index 4eeb69a88734..b721955d382e 100644
--- a/trunk/fs/block_dev.c
+++ b/trunk/fs/block_dev.c
@@ -852,6 +852,34 @@ struct block_device *open_by_devnum(dev_t dev, unsigned mode)
 
 EXPORT_SYMBOL(open_by_devnum);
 
+/**
+ * check_disk_size_change - checks for disk size change and adjusts
+ *                          bdev size.
+ *
+ * @disk: struct gendisk to check
+ * @bdev: struct bdev to adjust.
+ *
+ * This routine checks to see if the bdev size does not match the disk size
+ * and adjusts it if it differs.
+ */
+void check_disk_size_change(struct gendisk *disk, struct block_device *bdev)
+{
+	loff_t disk_size, bdev_size;
+
+	disk_size = (loff_t)get_capacity(disk) << 9;
+	bdev_size = i_size_read(bdev->bd_inode);
+	if (disk_size != bdev_size) {
+		char name[BDEVNAME_SIZE];
+
+		disk_name(disk, 0, name);
+		printk(KERN_INFO
+		       "%s: detected capacity change from %lld to %lld\n",
+		       name, bdev_size, disk_size);
+		i_size_write(bdev->bd_inode, disk_size);
+	}
+}
+EXPORT_SYMBOL(check_disk_size_change);
+
 /**
  * revalidate_disk - wrapper for lower-level driver's revalidate_disk
  *                   call-back
@@ -864,11 +892,20 @@ EXPORT_SYMBOL(open_by_devnum);
  */
 int revalidate_disk(struct gendisk *disk)
 {
+	struct block_device *bdev;
 	int ret = 0;
 
 	if (disk->fops->revalidate_disk)
 		ret = disk->fops->revalidate_disk(disk);
 
+	bdev = bdget_disk(disk, 0);
+	if (!bdev)
+		return ret;
+
+	mutex_lock(&bdev->bd_mutex);
+	check_disk_size_change(disk, bdev);
+	mutex_unlock(&bdev->bd_mutex);
+	bdput(bdev);
 	return ret;
 }
 EXPORT_SYMBOL(revalidate_disk);
diff --git a/trunk/include/linux/fs.h b/trunk/include/linux/fs.h
index d63461f97983..32477e8872d5 100644
--- a/trunk/include/linux/fs.h
+++ b/trunk/include/linux/fs.h
@@ -1722,6 +1722,8 @@ extern int fs_may_remount_ro(struct super_block *);
  */
 #define bio_data_dir(bio)	((bio)->bi_rw & 1)
 
+extern void check_disk_size_change(struct gendisk *disk,
+				   struct block_device *bdev);
 extern int revalidate_disk(struct gendisk *);
 extern int check_disk_change(struct block_device *);
 extern int __invalidate_device(struct block_device *);