btrfs: use non-RCU list traversal in write_all_supers callees
We take the fs_devices::device_list_mutex mutex in write_all_supers
which will prevent any add/del changes to the device list. Therefore we
don't need to use the RCU variant list_for_each_entry_rcu in any of the
called functions.
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index ec9aa34..06c5937 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3395,9 +3395,10 @@ static int barrier_all_devices(struct btrfs_fs_info *info)
int errors_wait = 0;
blk_status_t ret;
+ lockdep_assert_held(&info->fs_devices->device_list_mutex);
/* send down all the barriers */
head = &info->fs_devices->devices;
- list_for_each_entry_rcu(dev, head, dev_list) {
+ list_for_each_entry(dev, head, dev_list) {
if (dev->missing)
continue;
if (!dev->bdev)
@@ -3410,7 +3411,7 @@ static int barrier_all_devices(struct btrfs_fs_info *info)
}
/* wait for all the barriers */
- list_for_each_entry_rcu(dev, head, dev_list) {
+ list_for_each_entry(dev, head, dev_list) {
if (dev->missing)
continue;
if (!dev->bdev) {
@@ -3509,7 +3510,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors)
}
}
- list_for_each_entry_rcu(dev, head, dev_list) {
+ list_for_each_entry(dev, head, dev_list) {
if (!dev->bdev) {
total_errors++;
continue;
@@ -3550,7 +3551,7 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors)
}
total_errors = 0;
- list_for_each_entry_rcu(dev, head, dev_list) {
+ list_for_each_entry(dev, head, dev_list) {
if (!dev->bdev)
continue;
if (!dev->in_fs_metadata || !dev->writeable)