X-Git-Url: https://git.camperquake.de/gitweb.cgi?a=blobdiff_plain;f=include%2Flinux%2Fblkdev_compat.h;fp=include%2Flinux%2Fblkdev_compat.h;h=47f569bbdaae2529b21d07cd74f623b1b0810eda;hb=8128bd89fb487d91a3335605b009ac2b7d5aecd3;hp=9d3e6f07cefc8b892310e2b20710e0568ee91cee;hpb=bd99a7584a3d93cffd6c57ef7b9c80ffd953d913;p=zfs.git

diff --git a/include/linux/blkdev_compat.h b/include/linux/blkdev_compat.h
index 9d3e6f0..47f569b 100644
--- a/include/linux/blkdev_compat.h
+++ b/include/linux/blkdev_compat.h
@@ -478,4 +478,13 @@ blk_queue_discard_granularity(struct request_queue *q, unsigned int dg)
  */
 #define	VDEV_SCHEDULER			"noop"
 
+/*
+ * A common holder for vdev_bdev_open() is used to relax the exclusive open
+ * semantics slightly.  Internal vdev disk callers may pass VDEV_HOLDER to
+ * allow them to open the device multiple times.  Other kernel callers and
+ * user space processes which don't pass this value will get EBUSY.  This is
+ * currently required for the correct operation of hot spares.
+ */
+#define VDEV_HOLDER			((void *)0x2f5401de7)
+
 #endif /* _ZFS_BLKDEV_H */