- /* Get to the index root value (it's been verified in read_inode). */
- ir = (INDEX_ROOT*)((u8*)ctx->attr +
- le16_to_cpu(ctx->attr->data.resident.value_offset));
+ /*
+ * Copy the index root attribute value to a buffer so that we can put
+ * the search context and unmap the mft record before calling the
+ * filldir() callback. We need to do this because of NFSd which calls
+ * ->lookup() from its filldir callback() and this causes NTFS to
+ * deadlock as ntfs_lookup() maps the mft record of the directory and
+ * we have got it mapped here already. The only solution is for us to
+ * unmap the mft record here so that a call to ntfs_lookup() is able to
+ * map the mft record without deadlocking.
+ */
+ rc = le32_to_cpu(ctx->attr->data.resident.value_length);
+ ir = (INDEX_ROOT*)kmalloc(rc, GFP_NOFS);
+ if (unlikely(!ir)) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+ /* Copy the index root value (it has been verified in read_inode). */
+ memcpy(ir, (u8*)ctx->attr +
+ le16_to_cpu(ctx->attr->data.resident.value_offset), rc);
+ put_attr_search_ctx(ctx);
+ unmap_mft_record(ndir);
+ ctx = NULL;
+ m = NULL;