NTFS: Change ntfs_rl_truncate_nolock() to throw away the runlist if the new
length is zero.
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c
index e4c4716..539fa2b 100644
--- a/fs/ntfs/runlist.c
+++ b/fs/ntfs/runlist.c
@@ -1455,6 +1455,7 @@
/**
* ntfs_rl_truncate_nolock - truncate a runlist starting at a specified vcn
+ * @vol: ntfs volume (needed for error output)
* @runlist: runlist to truncate
* @new_length: the new length of the runlist in VCNs
*
@@ -1462,12 +1463,16 @@
* holding the runlist elements to a length of @new_length VCNs.
*
* If @new_length lies within the runlist, the runlist elements with VCNs of
- * @new_length and above are discarded.
+ * @new_length and above are discarded. As a special case if @new_length is
+ * zero, the runlist is discarded and set to NULL.
*
* If @new_length lies beyond the runlist, a sparse runlist element is added to
* the end of the runlist @runlist or if the last runlist element is a sparse
* one already, this is extended.
*
+ * Note, no checking is done for unmapped runlist elements. It is assumed that
+ * the caller has mapped any elements that need to be mapped already.
+ *
* Return 0 on success and -errno on error.
*
* Locking: The caller must hold @runlist->lock for writing.
@@ -1482,6 +1487,13 @@
BUG_ON(!runlist);
BUG_ON(new_length < 0);
rl = runlist->rl;
+ if (!new_length) {
+ ntfs_debug("Freeing runlist.");
+ runlist->rl = NULL;
+ if (rl)
+ ntfs_free(rl);
+ return 0;
+ }
if (unlikely(!rl)) {
/*
* Create a runlist consisting of a sparse runlist element of