allow the temp files created by open() to be linked to

O_TMPFILE | O_CREAT => linkat() with AT_SYMLINK_FOLLOW and /proc/self/fd/<n>
as oldpath (i.e. flink()) will create a link
O_TMPFILE | O_CREAT | O_EXCL => ENOENT on attempt to link those guys

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 00d5fc3b86e1..d6dfb09c8280 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -333,8 +333,10 @@ EXPORT_SYMBOL(set_nlink);
  */
 void inc_nlink(struct inode *inode)
 {
-        if (WARN_ON(inode->i_nlink == 0))
+        if (unlikely(inode->i_nlink == 0)) {
+                WARN_ON(!(inode->i_state & I_LINKABLE));
                 atomic_long_dec(&inode->i_sb->s_remove_count);
+        }
 
         inode->__i_nlink++;
 }