Btrfs: Don't do btree balance_dirty_pages on old kernels, it stalls forever
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9d5424a..c308316 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1655,6 +1655,11 @@
void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
{
+ /*
+ * looks as though older kernels can get into trouble with
+ * this code, they end up stuck in balance_dirty_pages forever
+ */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,23)
struct extent_io_tree *tree;
u64 num_dirty;
u64 start = 0;
@@ -1670,6 +1675,9 @@
balance_dirty_pages_ratelimited_nr(
root->fs_info->btree_inode->i_mapping, 1);
}
+#else
+ return;
+#endif
}
void btrfs_set_buffer_defrag(struct extent_buffer *buf)