Btrfs: do not pin while under spin lock

When testing a corrupted fs I noticed I was getting sleep while atomic errors
when the transaction aborted.  This is because btrfs_pin_extent may need to
allocate memory and we are calling this under the spin lock.  Fix this by moving
it out and doing the pin after dropping the spin lock but before dropping the
mutex, the same way it works when delayed refs run normally.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9b7020197c71821314d4a0c044086cadcb64cd28..3c2886ca7d8cbac3ffe353a0280a1831e53ec2ff 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3762,6 +3762,7 @@ int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
 
        while ((node = rb_first(&delayed_refs->root)) != NULL) {
                struct btrfs_delayed_ref_head *head = NULL;
+               bool pin_bytes = false;
 
                ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
                atomic_set(&ref->refs, 1);
@@ -3782,8 +3783,7 @@ int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
                        }
 
                        if (head->must_insert_reserved)
-                               btrfs_pin_extent(root, ref->bytenr,
-                                                ref->num_bytes, 1);
+                               pin_bytes = true;
                        btrfs_free_delayed_extent_op(head->extent_op);
                        delayed_refs->num_heads--;
                        if (list_empty(&head->cluster))
@@ -3794,9 +3794,13 @@ int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
                ref->in_tree = 0;
                rb_erase(&ref->rb_node, &delayed_refs->root);
                delayed_refs->num_entries--;
-               if (head)
-                       mutex_unlock(&head->mutex);
                spin_unlock(&delayed_refs->lock);
+               if (head) {
+                       if (pin_bytes)
+                               btrfs_pin_extent(root, ref->bytenr,
+                                                ref->num_bytes, 1);
+                       mutex_unlock(&head->mutex);
+               }
                btrfs_put_delayed_ref(ref);
 
                cond_resched();