From: Josef Bacik josef@toxicpanda.com
commit 54fde91f52f515e0b1514f0f0fa146e87a672227 upstream.
Christoph pointed out that I'm updating bdev->bd_inode for the device time when we remove block devices from a btrfs file system, however this isn't actually exposed to anything. The inode we want to update is the one that's associated with the path to the device, usually on devtmpfs, so that blkid notices the difference.
We still don't want to do the blkdev_open, so use kern_path() to get the path to the given device and do the update time on that inode.
Fixes: 8f96a5bfa150 ("btrfs: update the bdev time directly when closing") Reported-by: Christoph Hellwig hch@lst.de Signed-off-by: Josef Bacik josef@toxicpanda.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/volumes.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-)
--- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -14,6 +14,7 @@ #include <linux/semaphore.h> #include <linux/uuid.h> #include <linux/list_sort.h> +#include <linux/namei.h> #include "misc.h" #include "ctree.h" #include "extent_map.h" @@ -1884,18 +1885,22 @@ out: /* * Function to update ctime/mtime for a given device path. * Mainly used for ctime/mtime based probe like libblkid. + * + * We don't care about errors here, this is just to be kind to userspace. */ -static void update_dev_time(struct block_device *bdev) +static void update_dev_time(const char *device_path) { - struct inode *inode = bdev->bd_inode; + struct path path; struct timespec64 now; + int ret;
- /* Shouldn't happen but just in case. */ - if (!inode) + ret = kern_path(device_path, LOOKUP_FOLLOW, &path); + if (ret) return;
- now = current_time(inode); - generic_update_time(inode, &now, S_MTIME | S_CTIME); + now = current_time(d_inode(path.dentry)); + inode_update_time(d_inode(path.dentry), &now, S_MTIME | S_CTIME); + path_put(&path); }
static int btrfs_rm_dev_item(struct btrfs_device *device) @@ -2071,7 +2076,7 @@ void btrfs_scratch_superblocks(struct bt btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
/* Update ctime/mtime for device path for libblkid */ - update_dev_time(bdev); + update_dev_time(device_path); }
int btrfs_rm_device(struct btrfs_fs_info *fs_info, const char *device_path, @@ -2735,7 +2740,7 @@ int btrfs_init_new_device(struct btrfs_f btrfs_forget_devices(device_path);
/* Update ctime/mtime for blkid or udev */ - update_dev_time(bdev); + update_dev_time(device_path);
return ret;