1 files changed, 63 insertions, 0 deletions

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index e4ebddd3c500..d98758a09677 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -43,6 +43,7 @@
 #include "xfs_quota.h"
 #include "xfs_trans_priv.h"
 #include "xfs_trans_space.h"
+#include "xfs_inode_item.h"
 
 
 STATIC void     xfs_trans_apply_sb_deltas(xfs_trans_t *);
@@ -1216,6 +1217,68 @@ xfs_trans_free(
         kmem_zone_free(xfs_trans_zone, tp);
 }
 
+/*
+ * Roll from one trans in the sequence of PERMANENT transactions to
+ * the next: permanent transactions are only flushed out when
+ * committed with XFS_TRANS_RELEASE_LOG_RES, but we still want as soon
+ * as possible to let chunks of it go to the log. So we commit the
+ * chunk we've been working on and get a new transaction to continue.
+ */
+int
+xfs_trans_roll(
+        struct xfs_trans        **tpp,
+        struct xfs_inode        *dp)
+{
+        struct xfs_trans        *trans;
+        unsigned int            logres, count;
+        int                     error;
+
+        /*
+         * Ensure that the inode is always logged.
+         */
+        trans = *tpp;
+        xfs_trans_log_inode(trans, dp, XFS_ILOG_CORE);
+
+        /*
+         * Copy the critical parameters from one trans to the next.
+         */
+        logres = trans->t_log_res;
+        count = trans->t_log_count;
+        *tpp = xfs_trans_dup(trans);
+
+        /*
+         * Commit the current transaction.
+         * If this commit failed, then it'd just unlock those items that
+         * are not marked ihold. That also means that a filesystem shutdown
+         * is in progress. The caller takes the responsibility to cancel
+         * the duplicate transaction that gets returned.
+         */
+        error = xfs_trans_commit(trans, 0);
+        if (error)
+                return (error);
+
+        trans = *tpp;
+
+        /*
+         * Reserve space in the log for th next transaction.
+         * This also pushes items in the "AIL", the list of logged items,
+         * out to disk if they are taking up space at the tail of the log
+         * that we want to use.  This requires that either nothing be locked
+         * across this call, or that anything that is locked be logged in
+         * the prior and the next transactions.
+         */
+        error = xfs_trans_reserve(trans, 0, logres, 0,
+                                  XFS_TRANS_PERM_LOG_RES, count);
+        /*
+         *  Ensure that the inode is in the new transaction and locked.
+         */
+        if (error)
+                return error;
+
+        xfs_trans_ijoin(trans, dp, XFS_ILOCK_EXCL);
+        xfs_trans_ihold(trans, dp);
+        return 0;
+}
 
 /*
  * THIS SHOULD BE REWRITTEN TO USE xfs_trans_next_item().