btrfs: relocation: add error injection points for cancelling balance
Introduce a new error injection point, should_cancel_balance().
It's just a wrapper of atomic_read(&fs_info->balance_cancel_req), but
allows us to override the return value.
Currently there are only one locations using this function:
- btrfs_balance()
It checks cancel before each block group.
There are other locations checking fs_info->balance_cancel_req, but they
are not used as an indicator to exit, so there is no need to use the
wrapper.
But there will be more locations coming, and some locations can cause
kernel panic if not handled properly. So introduce this error injection
to provide better test interface.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index ecd016f..e490cfd 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3378,6 +3378,7 @@
u64 *bytes_to_reserve);
int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
struct btrfs_pending_snapshot *pending);
+int btrfs_should_cancel_balance(struct btrfs_fs_info *fs_info);
/* scrub.c */
int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index ba39f69..0238801 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -9,6 +9,7 @@
#include <linux/blkdev.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
+#include <linux/error-injection.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
@@ -3314,6 +3315,15 @@
return ret;
}
+/*
+ * Allow error injection to test balance cancellation
+ */
+int btrfs_should_cancel_balance(struct btrfs_fs_info *fs_info)
+{
+ return atomic_read(&fs_info->balance_cancel_req);
+}
+ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE);
+
static int relocate_file_extent_cluster(struct inode *inode,
struct file_extent_cluster *cluster)
{
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 74c34c3..c1909e5 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3994,7 +3994,7 @@
if (btrfs_fs_closing(fs_info) ||
atomic_read(&fs_info->balance_pause_req) ||
- atomic_read(&fs_info->balance_cancel_req)) {
+ btrfs_should_cancel_balance(fs_info)) {
ret = -EINVAL;
goto out;
}
