| Message ID | a1938a2cc8a66c24293b19aa91526d6eac433b10.1381497087.git.sbehrens@giantdisaster.de (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Fri, Oct 11, 2013 at 03:20:42PM +0200, Stefan Behrens wrote: > 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 > Sounds like something that would look great in xfstests, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 646d10d..9837439 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -2041,6 +2041,7 @@ 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); Doesn't valid mean that the in-memory atomics reflect the counts in the btree items? Am I misunderstanding? Seems like a reproducer would be: get non-zero stats, unmount, mount, get stats strictly >=. - z -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> a filesystem is mounted. They set the device stats to zero by using > kzalloc() which is correct for new devices. Oh, right, got it :) - z -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 646d10d..9837439 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2041,6 +2041,7 @@ 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) { @@ -2208,6 +2209,7 @@ 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);
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> --- The idea to fix this issue, the subject line of the patch and parts of the commit log are reused from a patch that Zach Brown has sent. fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+)