From 27087f370174ebb298cdf6dcb36b1e4dcbe34e93 Mon Sep 17 00:00:00 2001 From: Stefan Behrens Date: Fri, 11 Oct 2013 15:20:42 +0200 Subject: [PATCH] Btrfs: init device stats for new devices Device stats are only initialized (read from tree items) on mount. Trying to read device stats after adding or replacing new devices will return errors. btrfs_init_new_device() and btrfs_init_dev_replace_tgtdev() are the two functions that allocate and initialize new btrfs_device structures after a filesystem is mounted. They set the device stats to zero by using kzalloc() which is correct for new devices. The only missing thing was to declare these stats as being valid (device->dev_stats_valid = 1) and this patch adds this missing code. This is the reproducer: TEST_DEV1=/dev/sdzzzzz1 TEST_DEV2=/dev/sdzzzzz2 TEST_DEV3=/dev/sdzzzzz3 TEST_MNT=/mnt mkfs.btrfs $TEST_DEV1 mount $TEST_DEV1 $TEST_MNT btrfs device add $TEST_DEV2 $TEST_MNT btrfs device stat $TEST_MNT btrfs replace start -B $TEST_DEV2 $TEST_DEV3 $TEST_MNT btrfs device stat $TEST_MNT umount $TEST_MNT Reported-by: Ondrej Kunc Signed-off-by: Stefan Behrens Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 5d7ea26..f492f7e 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2042,6 +2042,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path) device->in_fs_metadata = 1; device->is_tgtdev_for_dev_replace = 0; device->mode = FMODE_EXCL; + device->dev_stats_valid = 1; set_blocksize(device->bdev, 4096); if (seeding_dev) { @@ -2209,6 +2210,7 @@ int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path, device->in_fs_metadata = 1; device->is_tgtdev_for_dev_replace = 1; device->mode = FMODE_EXCL; + device->dev_stats_valid = 1; set_blocksize(device->bdev, 4096); device->fs_devices = fs_info->fs_devices; list_add(&device->dev_list, &fs_info->fs_devices->devices); -- 2.7.4