From a6b0d5c8dbfd428717fc4db4c36757783f391c7b Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 20 Feb 2012 20:53:43 -0500 Subject: Btrfs: make sure we update latest_bdev When we are setting up the mount, we close all the devices that were not actually part of the metadata we found. But, we don't make sure that one of those devices wasn't fs_devices->latest_bdev, which means we can do a use after free on the one we closed. This updates latest_bdev as it goes. Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/volumes.c') diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index cd040bf3fd87..7eefdef8a14c 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -459,12 +459,23 @@ int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices) { struct btrfs_device *device, *next; + struct block_device *latest_bdev = NULL; + u64 latest_devid = 0; + u64 latest_transid = 0; + mutex_lock(&uuid_mutex); again: /* This is the initialized path, it is safe to release the devices. */ list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) { - if (device->in_fs_metadata) + if (device->in_fs_metadata) { + if (!latest_transid || + device->generation > latest_transid) { + latest_devid = device->devid; + latest_transid = device->generation; + latest_bdev = device->bdev; + } continue; + } if (device->bdev) { blkdev_put(device->bdev, device->mode); @@ -487,6 +498,10 @@ again: goto again; } + fs_devices->latest_bdev = latest_bdev; + fs_devices->latest_devid = latest_devid; + fs_devices->latest_trans = latest_transid; + mutex_unlock(&uuid_mutex); return 0; } -- cgit v1.2.3