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Btrfs: fix the race between reading and updating devices

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On btrfs_congested_fn and __unplug_io_fn paths, we should hold
device_list_mutex to avoid remove/add device path to
update fs_devices->devices

On __btrfs_close_devices and btrfs_prepare_sprout paths, the devices in
fs_devices->devices or fs_devices->devices is updated, so we should hold
the mutex to avoid the reader side to reach them

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Xiao Guangrong
2011-04-20 10:07:30 +00:00
committed by Chris Mason
parent 4f6c9328c6
commit c9513edb00
2 changed files with 9 additions and 0 deletions
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2
fs/btrfs/disk-io.c
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@@ -1410,6 +1410,7 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits)
struct btrfs_device *device;
struct backing_dev_info *bdi;
mutex_lock(&info->fs_devices->device_list_mutex);
list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
if (!device->bdev)
continue;
@@ -1419,6 +1420,7 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits)
break;
}
}
mutex_unlock(&info->fs_devices->device_list_mutex);
return ret;
}