linux-kernel - [PATCH 2/6] Adjust block device size after an online resize of a disk.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20080829231305.25065.3834.stgit@bluto.andrew>
Date:	Fri, 29 Aug 2008 17:13:05 -0600
From:	Andrew Patterson <andrew.patterson@...com>
To:	linux-scsi@...r.kernel.org
Cc:	andrew.patterson@...com, James.Bottomley@...senPartnership.com,
	linux-kernel@...r.kernel.org, viro@...iv.linux.org.uk,
	axboe@...nel.dk, andmike@...ux.vnet.ibm.com, mike.miller@...com,
	genanr@...phone.com, jmoyer@...hat.com
Subject: [PATCH 2/6] Adjust block device size after an online resize of a disk.

Adjust block device size after an online resize of a disk.

The revalidate_disk routine now checks if a disk has been resized by
comparing the gendisk capacity to the bdev inode size.  If they are
different (usually because the disk has been resized underneath the kernel)
the bdev inode size is adjusted to match the capacity.

Signed-off-by: Andrew Patterson <andrew.patterson@...com>
---

 fs/block_dev.c     |   37 +++++++++++++++++++++++++++++++++++++
 include/linux/fs.h |    2 ++
 2 files changed, 39 insertions(+), 0 deletions(-)


diff --git a/fs/block_dev.c b/fs/block_dev.c
index 30bafca..f8df73a 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -869,6 +869,34 @@ 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
  *
@@ -880,11 +908,20 @@ 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/include/linux/fs.h b/include/linux/fs.h
index 28756a9..ef23c3f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1718,6 +1718,8 @@ 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 *);

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/