PM/hibernate: fix "swap breaks after hibernation failures"
authorAlan Jenkins <alan-jenkins@tuffmail.co.uk>
Sat, 14 Feb 2009 01:01:14 +0000 (02:01 +0100)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 21 Feb 2009 22:17:17 +0000 (14:17 -0800)
http://bugzilla.kernel.org/show_bug.cgi?id=12239

The image writing code dropped a reference to the current swap device.
This doesn't show up if the hibernation succeeds - because it doesn't
affect the image which gets resumed.  But it means multiple _failed_
hibernations end up freeing the swap device while it is still use!

swsusp_write() finds the block device for the swap file using swap_type_of().
It then uses blkdev_get() / blkdev_put() to open and close the block device.

Unfortunately, blkdev_get() assumes ownership of the inode of the block_device
passed to it.  So blkdev_put() calls iput() on the inode.  This is by design
and other callers expect this behaviour.  The fix is for swap_type_of() to take
a reference on the inode using bdget().

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/swapfile.c

index 7e6304dfafab174884bad5820a0194f449906a32..312fafe0ab6ed4815ac02da3f712aca18bacbbad 100644 (file)
@@ -635,7 +635,7 @@ int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p)
 
                if (!bdev) {
                        if (bdev_p)
-                               *bdev_p = sis->bdev;
+                               *bdev_p = bdget(sis->bdev->bd_dev);
 
                        spin_unlock(&swap_lock);
                        return i;
@@ -647,7 +647,7 @@ int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p)
                                        struct swap_extent, list);
                        if (se->start_block == offset) {
                                if (bdev_p)
-                                       *bdev_p = sis->bdev;
+                                       *bdev_p = bdget(sis->bdev->bd_dev);
 
                                spin_unlock(&swap_lock);
                                bdput(bdev);