summaryrefslogtreecommitdiff
path: root/fs/btrfs/volumes.c
diff options
context:
space:
mode:
authorAnand Jain <anand.jain@oracle.com>2022-01-12 13:05:59 +0800
committerDavid Sterba <dsterba@suse.com>2022-03-14 13:13:46 +0100
commit770c79fb65506fc7c16459855c3839429f46cb32 (patch)
treef306d74b6040d9db7bef92e1dacec6b15237b03f /fs/btrfs/volumes.c
parentbef16b52987b3cd18222109e2490b2f48018cd95 (diff)
btrfs: harden identification of a stale device
Identifying and removing the stale device from the fs_uuids list is done by btrfs_free_stale_devices(). btrfs_free_stale_devices() in turn depends on device_path_matched() to check if the device appears in more than one btrfs_device structure. The matching of the device happens by its path, the device path. However, when device mapper is in use, the dm device paths are nothing but a link to the actual block device, which leads to the device_path_matched() failing to match. Fix this by matching the dev_t as provided by lookup_bdev() instead of plain string compare of the device paths. Reported-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/volumes.c')
-rw-r--r--fs/btrfs/volumes.c45
1 files changed, 38 insertions, 7 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 76b6957c619b..188e2a61402d 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -534,15 +534,48 @@ error:
return ret;
}
-static bool device_path_matched(const char *path, struct btrfs_device *device)
+/*
+ * Check if the device in the path matches the device in the given struct device.
+ *
+ * Returns:
+ * true If it is the same device.
+ * false If it is not the same device or on error.
+ */
+static bool device_matched(const struct btrfs_device *device, const char *path)
{
- int found;
+ char *device_name;
+ dev_t dev_old;
+ dev_t dev_new;
+ int ret;
+
+ /*
+ * If we are looking for a device with the matching dev_t, then skip
+ * device without a name (a missing device).
+ */
+ if (!device->name)
+ return false;
+
+ device_name = kzalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL);
+ if (!device_name)
+ return false;
rcu_read_lock();
- found = strcmp(rcu_str_deref(device->name), path);
+ scnprintf(device_name, BTRFS_PATH_NAME_MAX, "%s", rcu_str_deref(device->name));
rcu_read_unlock();
- return found == 0;
+ ret = lookup_bdev(device_name, &dev_old);
+ kfree(device_name);
+ if (ret)
+ return false;
+
+ ret = lookup_bdev(path, &dev_new);
+ if (ret)
+ return false;
+
+ if (dev_old == dev_new)
+ return true;
+
+ return false;
}
/*
@@ -575,9 +608,7 @@ static int btrfs_free_stale_devices(const char *path,
&fs_devices->devices, dev_list) {
if (skip_device && skip_device == device)
continue;
- if (path && !device->name)
- continue;
- if (path && !device_path_matched(path, device))
+ if (path && !device_matched(device, path))
continue;
if (fs_devices->opened) {
/* for an already deleted device return 0 */