1 files changed, 37 insertions, 26 deletions

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index c4ec7afd1170..edbe37b7f636 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1190,11 +1190,11 @@ xfs_reflink_remap_blocks(
 }
 
 /*
- * Grab the exclusive iolock for a data copy from src to dest, making
- * sure to abide vfs locking order (lowest pointer value goes first) and
- * breaking the pnfs layout leases on dest before proceeding.  The loop
- * is needed because we cannot call the blocking break_layout() with the
- * src iolock held, and therefore have to back out both locks.
+ * Grab the exclusive iolock for a data copy from src to dest, making sure to
+ * abide vfs locking order (lowest pointer value goes first) and breaking the
+ * layout leases before proceeding.  The loop is needed because we cannot call
+ * the blocking break_layout() with the iolocks held, and therefore have to
+ * back out both locks.
  */
 static int
 xfs_iolock_two_inodes_and_break_layout(
@@ -1203,33 +1203,44 @@ xfs_iolock_two_inodes_and_break_layout(
 {
         int                     error;
 
-retry:
-        if (src < dest) {
-                inode_lock_shared(src);
-                inode_lock_nested(dest, I_MUTEX_NONDIR2);
-        } else {
-                /* src >= dest */
-                inode_lock(dest);
-        }
+        if (src > dest)
+                swap(src, dest);
 
-        error = break_layout(dest, false);
-        if (error == -EWOULDBLOCK) {
-                inode_unlock(dest);
-                if (src < dest)
-                        inode_unlock_shared(src);
+retry:
+        /* Wait to break both inodes' layouts before we start locking. */
+        error = break_layout(src, true);
+        if (error)
+                return error;
+        if (src != dest) {
                 error = break_layout(dest, true);
                 if (error)
                         return error;
-                goto retry;
         }
+
+        /* Lock one inode and make sure nobody got in and leased it. */
+        inode_lock(src);
+        error = break_layout(src, false);
         if (error) {
+                inode_unlock(src);
+                if (error == -EWOULDBLOCK)
+                        goto retry;
+                return error;
+        }
+
+        if (src == dest)
+                return 0;
+
+        /* Lock the other inode and make sure nobody got in and leased it. */
+        inode_lock_nested(dest, I_MUTEX_NONDIR2);
+        error = break_layout(dest, false);
+        if (error) {
+                inode_unlock(src);
                 inode_unlock(dest);
-                if (src < dest)
-                        inode_unlock_shared(src);
+                if (error == -EWOULDBLOCK)
+                        goto retry;
                 return error;
         }
-        if (src > dest)
-                inode_lock_shared_nested(src, I_MUTEX_NONDIR2);
+
         return 0;
 }
 
@@ -1247,10 +1258,10 @@ xfs_reflink_remap_unlock(
 
         xfs_iunlock(dest, XFS_MMAPLOCK_EXCL);
         if (!same_inode)
-                xfs_iunlock(src, XFS_MMAPLOCK_SHARED);
+                xfs_iunlock(src, XFS_MMAPLOCK_EXCL);
         inode_unlock(inode_out);
         if (!same_inode)
-                inode_unlock_shared(inode_in);
+                inode_unlock(inode_in);
 }
 
 /*
@@ -1325,7 +1336,7 @@ xfs_reflink_remap_prep(
         if (same_inode)
                 xfs_ilock(src, XFS_MMAPLOCK_EXCL);
         else
-                xfs_lock_two_inodes(src, XFS_MMAPLOCK_SHARED, dest,
+                xfs_lock_two_inodes(src, XFS_MMAPLOCK_EXCL, dest,
                                 XFS_MMAPLOCK_EXCL);
 
         /* Check file eligibility and prepare for block sharing. */