From 9f7eb8405dcbc79c5434821e9e3e92abe187ee8e Mon Sep 17 00:00:00 2001 From: Anand Jain Date: Fri, 1 Mar 2024 08:42:13 +0800 Subject: btrfs: validate device maj:min during open Boris managed to create a device capable of changing its maj:min without altering its device path. Only multi-devices can be scanned. A device that gets scanned and remains in the btrfs kernel cache might end up with an incorrect maj:min. Despite the temp-fsid feature patch did not introduce this bug, it could lead to issues if the above multi-device is converted to a single device with a stale maj:min. Subsequently, attempting to mount the same device with the correct maj:min might mistake it for another device with the same fsid, potentially resulting in wrongly auto-enabling the temp-fsid feature. To address this, this patch validates the device's maj:min at the time of device open and updates it if it has changed since the last scan. CC: stable@vger.kernel.org # 6.7+ Fixes: a5b8a5f9f835 ("btrfs: support cloned-device mount capability") Reported-by: Boris Burkov Co-developed-by: Boris Burkov Reviewed-by: Boris Burkov # Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/volumes.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'fs/btrfs/volumes.c') diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index e49935a54da0..c318640b4472 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -692,6 +692,16 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices, device->bdev = bdev_handle->bdev; clear_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state); + if (device->devt != device->bdev->bd_dev) { + btrfs_warn(NULL, + "device %s maj:min changed from %d:%d to %d:%d", + device->name->str, MAJOR(device->devt), + MINOR(device->devt), MAJOR(device->bdev->bd_dev), + MINOR(device->bdev->bd_dev)); + + device->devt = device->bdev->bd_dev; + } + fs_devices->open_devices++; if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) && device->devid != BTRFS_DEV_REPLACE_DEVID) { -- cgit v1.2.3 From 2f1aeab9fca1a5f583be1add175d1ee95c213cfa Mon Sep 17 00:00:00 2001 From: Anand Jain Date: Tue, 19 Mar 2024 08:28:18 +0530 Subject: btrfs: return accurate error code on open failure in open_fs_devices() When attempting to exclusive open a device which has no exclusive open permission, such as a physical device associated with the flakey dm device, the open operation will fail, resulting in a mount failure. In this particular scenario, we erroneously return -EINVAL instead of the correct error code provided by the bdev_open_by_path() function, which is -EBUSY. Fix this, by returning error code from the bdev_open_by_path() function. With this correction, the mount error message will align with that of ext4 and xfs. Reviewed-by: Boris Burkov Signed-off-by: Anand Jain Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/volumes.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) (limited to 'fs/btrfs/volumes.c') diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index c318640b4472..dedec3d9b111 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1184,23 +1184,30 @@ static int open_fs_devices(struct btrfs_fs_devices *fs_devices, struct btrfs_device *device; struct btrfs_device *latest_dev = NULL; struct btrfs_device *tmp_device; + int ret = 0; list_for_each_entry_safe(device, tmp_device, &fs_devices->devices, dev_list) { - int ret; + int ret2; - ret = btrfs_open_one_device(fs_devices, device, flags, holder); - if (ret == 0 && + ret2 = btrfs_open_one_device(fs_devices, device, flags, holder); + if (ret2 == 0 && (!latest_dev || device->generation > latest_dev->generation)) { latest_dev = device; - } else if (ret == -ENODATA) { + } else if (ret2 == -ENODATA) { fs_devices->num_devices--; list_del(&device->dev_list); btrfs_free_device(device); } + if (ret == 0 && ret2 != 0) + ret = ret2; } - if (fs_devices->open_devices == 0) + + if (fs_devices->open_devices == 0) { + if (ret) + return ret; return -EINVAL; + } fs_devices->opened = 1; fs_devices->latest_dev = latest_dev; -- cgit v1.2.3