[PATCH 3.10 64/77] btrfs: Add ctime/mtime update for btrfs device add/remove.

Greg Kroah-Hartman
2014-06-28T19:03:26Z

From: Qu Wenruo <quwenruo@cn.fujitsu.com>

commit 5a1972bd9fd4b2fb1bac8b7a0b636d633d8717e3 upstream.

Btrfs will send uevent to udev inform the device change,
but ctime/mtime for the block device inode is not udpated, which cause
libblkid used by btrfs-progs unable to detect device change and use old
cache, causing 'btrfs dev scan; btrfs dev rmove; btrfs dev scan' give an
error message.

Reported-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/btrfs/volumes.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1384,6 +1384,22 @@ out:
return ret;
}

+/*
+ * Function to update ctime/mtime for a given device path.
+ * Mainly used for ctime/mtime based probe like libblkid.
+ */
+static void update_dev_time(char *path_name)
+{
+ struct file *filp;
+
+ filp = filp_open(path_name, O_RDWR, 0);
+ if (!filp)
+ return;
+ file_update_time(filp);
+ filp_close(filp, NULL);
+ return;
+}
+
static int btrfs_rm_dev_item(struct btrfs_root *root,
struct btrfs_device *device)
{
@@ -1642,10 +1658,14 @@ int btrfs_rm_device(struct btrfs_root *r

ret = 0;

- /* Notify udev that device has changed */
- if (bdev)
+ if (bdev) {
+ /* Notify udev that device has changed */
btrfs_kobject_uevent(bdev, KOBJ_CHANGE);

+ /* Update ctime/mtime for device path for libblkid */
+ update_dev_time(device_path);
+ }
+
error_brelse:
brelse(bh);
if (bdev)
@@ -2089,6 +2109,8 @@ int btrfs_init_new_device(struct btrfs_r
ret = btrfs_commit_transaction(trans, root);
}

+ /* Update ctime/mtime for libblkid */
+ update_dev_time(device_path);
return ret;