Hi Qu,
In line below...
On 16/04/14 17:02, Qu Wenruo wrote:
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@xxxxxxxxxxxxxx>
Cc: Karel Zak <kzak@xxxxxxxxxx>
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
fs/btrfs/volumes.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 49d7fab..ce232d7 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1452,6 +1452,22 @@ 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;
+}
+
IMO /(I might be wrong) I think its not a good idea to explicitly
achieve this. Since this thread would have already scratched the
device's SB, shouldn't that take care of updating the mtime ?
Thanks, Anand
static int btrfs_rm_dev_item(struct btrfs_root *root,
struct btrfs_device *device)
{
@@ -1704,10 +1720,14 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
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)
@@ -2146,6 +2166,8 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
ret = btrfs_commit_transaction(trans, root);
}
+ /* Update ctime/mtime for libblkid */
+ update_dev_time(device_path);
return ret;
error_trans:
--
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