--- fs/xfs/xfs_iomap.c

+++ fs/xfs/xfs_iomap.c

@@ -860,8 +860,15 @@ xfs_iomap_write_unwritten(

* set up a transaction to convert the range of extents

* from unwritten to real. Do allocations in a loop until

* we have covered the range passed in.

+ *

+ * Note that we open code the transaction allocation here

+ * to pass KM_NOFS--we can't risk to recursing back into

+ * the filesystem here as we might be asked to write out

+ * the same inode that we complete here and might deadlock

+ * on the iolock.

*/

- tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);

+ xfs_wait_for_freeze(mp, SB_FREEZE_TRANS);

+ tp = _xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE, KM_NOFS);

tp->t_flags |= XFS_TRANS_RESERVE;

error = xfs_trans_reserve(tp, resblks,

XFS_WRITE_LOG_RES(mp), 0,