Commit 27087f37 authored Oct 11, 2013 by Stefan Behrens Committed by Chris Mason Nov 11, 2013

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 <kunc88@gmail.com>
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

parent 30d133fc

fs/btrfs/volumes.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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);

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