Now that sb-level/bdev-level fsfreeze integration has been achieved and
sb-lebel/bdev-level freeze counters are always kept consistent, we need to
unfreeze bdevs in addition to filesystems during emergency thaw so that
we can recover from a situation where someone forgot to call thaw_bdev().
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Cc: Josef Bacik <jbacik@xxxxxxxxxxxx>
Cc: Eric Sandeen <sandeen@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Dave Chinner <dchinner@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Luiz Capitulino <lcapitulino@xxxxxxxxxx>
Signed-off-by: Fernando Luis Vazquez Cao <fernando@xxxxxxxxxxxxx>
---
diff -urNp linux-3.8-rc1-orig/fs/block_dev.c linux-3.8-rc1/fs/block_dev.c
--- linux-3.8-rc1-orig/fs/block_dev.c 2012-12-25 16:33:38.664018000 +0900
+++ linux-3.8-rc1/fs/block_dev.c 2012-12-25 16:34:01.900018000 +0900
@@ -254,18 +254,18 @@ out:
EXPORT_SYMBOL(freeze_bdev);
/**
- * thaw_bdev - unlock a block device
+ * __thaw_bdev - unlock a block device
* @bdev: blockdevice to unlock
* @sb: associated superblock
*
* Unlocks the block device and, if present, the associated filesystem too.
+ * This is the unlocked version of thaw_bdev and it has to be called with
+ * ->bd_fsfreeze_mutex mutex taken.
*/
-int thaw_bdev(struct block_device *bdev, struct super_block *sb)
+static int __thaw_bdev(struct block_device *bdev, struct super_block *sb)
{
int error = -EINVAL;
- mutex_lock(&bdev->bd_fsfreeze_mutex);
-
if (!bdev->bd_fsfreeze_count)
goto out;
@@ -279,11 +279,49 @@ int thaw_bdev(struct block_device *bdev,
if (error)
bdev->bd_fsfreeze_count++;
out:
+ return error;
+}
+
+/**
+ * thaw_bdev -- unlock a block device
+ * @bdev: blockdevice to unlock
+ * @sb: associated superblock
+ *
+ * Unlocks the block device and, if present, the associated filesystem too.
+ */
+int thaw_bdev(struct block_device *bdev, struct super_block *sb)
+{
+ int error;
+ mutex_lock(&bdev->bd_fsfreeze_mutex);
+ error = __thaw_bdev(bdev, sb);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return error;
}
EXPORT_SYMBOL(thaw_bdev);
+void do_thaw_one_bdev(struct block_device *bdev, void *arg)
+{
+ struct super_block *sb;
+
+ mutex_lock(&bdev->bd_fsfreeze_mutex);
+
+ if (!bdev->bd_fsfreeze_count) {
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+ return;
+ }
+
+ /*
+ * We know the block device is frozen so we do not need to grab a
+ * reference - the first call to thaw_bdev() dit it.
+ */
+ if ((sb = get_super(bdev)) != NULL)
+ drop_super(sb);
+
+ while (!__thaw_bdev(bdev, sb));
+
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+}
+
static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, blkdev_get_block, wbc);
diff -urNp linux-3.8-rc1-orig/fs/super.c linux-3.8-rc1/fs/super.c
--- linux-3.8-rc1-orig/fs/super.c 2012-12-25 16:33:38.664018000 +0900
+++ linux-3.8-rc1/fs/super.c 2012-12-25 16:34:01.900018000 +0900
@@ -1585,7 +1585,7 @@ int thaw_super_force(struct super_block
return 0;
}
-static void do_thaw_one(struct super_block *sb, void *unused)
+static void do_thaw_one_sb(struct super_block *sb, void *unused)
{
int error;
@@ -1611,7 +1611,8 @@ static void do_thaw_one(struct super_blo
static void do_thaw_all(struct work_struct *work)
{
- iterate_supers_write(do_thaw_one, NULL);
+ iterate_bdevs(do_thaw_one_bdev, NULL);
+ iterate_supers_write(do_thaw_one_sb, NULL);
kfree(work);
printk(KERN_WARNING "Emergency Thaw complete\n");
}
diff -urNp linux-3.8-rc1-orig/include/linux/fs.h linux-3.8-rc1/include/linux/fs.h
--- linux-3.8-rc1-orig/include/linux/fs.h 2012-12-25 16:33:38.664018000 +0900
+++ linux-3.8-rc1/include/linux/fs.h 2012-12-25 16:34:01.904018000 +0900
@@ -2063,6 +2063,7 @@ extern int sync_blockdev(struct block_de
extern void kill_bdev(struct block_device *);
extern struct super_block *freeze_bdev(struct block_device *);
extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
+extern void do_thaw_one_bdev(struct block_device *bdev, void *arg);
extern int fsync_bdev(struct block_device *);
#else
static inline void bd_forget(struct inode *inode) {}
@@ -2080,6 +2081,10 @@ static inline int thaw_bdev(struct block
return 0;
}
+static inline void do_thaw_one_bdev(struct block_device *bdev, void *arg)
+{
+}
+
static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg)
{
}
--
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