Merge tag 'zonefs-5.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs

Pull zonefs fixes from Damien Le Moal:
 "Two fixes in here:

   - Revert the initial decision to silently ignore IOCB_NOWAIT for
     asynchronous direct IOs to sequential zone files. Instead, return
     an error to the user to signal that the feature is not supported
     (from Christoph)

   - A fix to zonefs Kconfig to select FS_IOMAP to avoid build failures
     if no other file system already selected this option (from
     Johannes)"

* tag 'zonefs-5.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs:
  zonefs: select FS_IOMAP
  zonefs: fix IOCB_NOWAIT handling

Author: torvalds

fs/zonefs/Kconfig

@@ -2,6 +2,7 @@ config ZONEFS_FS
 	tristate "zonefs filesystem support"
 	depends on BLOCK
 	depends on BLK_DEV_ZONED
+	select FS_IOMAP
 	help
 	  zonefs is a simple file system which exposes zones of a zoned block
 	  device (e.g. host-managed or host-aware SMR disk drives) as files.

fs/zonefs/super.c

@@ -601,13 +601,13 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
 	ssize_t ret;
 
 	/*
-	 * For async direct IOs to sequential zone files, ignore IOCB_NOWAIT
+	 * For async direct IOs to sequential zone files, refuse IOCB_NOWAIT
 	 * as this can cause write reordering (e.g. the first aio gets EAGAIN
 	 * on the inode lock but the second goes through but is now unaligned).
 	 */
-	if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !is_sync_kiocb(iocb)
-	    && (iocb->ki_flags & IOCB_NOWAIT))
-		iocb->ki_flags &= ~IOCB_NOWAIT;
+	if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !is_sync_kiocb(iocb) &&
+	    (iocb->ki_flags & IOCB_NOWAIT))
+		return -EOPNOTSUPP;
 
 	if (iocb->ki_flags & IOCB_NOWAIT) {
 		if (!inode_trylock(inode))