lkml.org 
[lkml]   [2021]   [Nov]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.15 277/279] btrfs: update device path inode time instead of bd_inode
    Date
    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;


    \
     
     \ /
      Last update: 2021-11-24 15:10    [W:5.446 / U:0.120 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site