1 files changed, 28 insertions, 8 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e28f3d4691af..5f06eb1f4384 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7116,21 +7116,41 @@ static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
         if (ret)
                 return ERR_PTR(ret);
 
-        em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
-                              ins.offset, ins.offset, ins.offset, 0);
-        if (IS_ERR(em)) {
-                btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
-                return em;
-        }
-
+        /*
+         * Create the ordered extent before the extent map. This is to avoid
+         * races with the fast fsync path that would lead to it logging file
+         * extent items that point to disk extents that were not yet written to.
+         * The fast fsync path collects ordered extents into a local list and
+         * then collects all the new extent maps, so we must create the ordered
+         * extent first and make sure the fast fsync path collects any new
+         * ordered extents after collecting new extent maps as well.
+         * The fsync path simply can not rely on inode_dio_wait() because it
+         * causes deadlock with AIO.
+         */
         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
                                            ins.offset, ins.offset, 0);
         if (ret) {
                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
-                free_extent_map(em);
                 return ERR_PTR(ret);
         }
 
+        em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
+                              ins.offset, ins.offset, ins.offset, 0);
+        if (IS_ERR(em)) {
+                struct btrfs_ordered_extent *oe;
+
+                btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 1);
+                oe = btrfs_lookup_ordered_extent(inode, start);
+                ASSERT(oe);
+                if (WARN_ON(!oe))
+                        return em;
+                set_bit(BTRFS_ORDERED_IOERR, &oe->flags);
+                set_bit(BTRFS_ORDERED_IO_DONE, &oe->flags);
+                btrfs_remove_ordered_extent(inode, oe);
+                /* Once for our lookup and once for the ordered extents tree. */
+                btrfs_put_ordered_extent(oe);
+                btrfs_put_ordered_extent(oe);
+        }
         return em;
 }