Btrfs devel - Feb 2008 - [PATCH 3/4] btrfs: Add workaround for bd_mount_sem

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 Versions prior to 2.6.20 used mutexes for bd_mount_sem.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>

- ---
 compat.h |    8 ++++++++
 super.c  |    5 +++--
 2 files changed, 11 insertions(+), 2 deletions(-)

- --- a/compat.h	2008-02-06 16:42:49.000000000 -0500
+++ b/compat.h	2008-02-06 16:44:42.000000000 -0500
@@ -16,4 +16,12 @@
 # endif
 #endif

+/* Versions earlier than 2.6.20 used mutex */
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,19)
+#define bd_mount_sem_down(bdev)	mutex_lock(&(bdev)->bd_mount_mutex)
+#define bd_mount_sem_up(bdev)	mutex_unlock(&(bdev)->bd_mount_mutex)
+#else
+#define bd_mount_sem_down(bdev)	down(&(bdev)->bd_mount_sem)
+#define bd_mount_sem_up(bdev)	up(&(bdev)->bd_mount_sem)
+#endif
 #endif /* _COMPAT_H_ */
- --- a/super.c	2008-02-06 11:37:39.000000000 -0500
+++ b/super.c	2008-02-06 16:44:42.000000000 -0500
@@ -43,6 +43,7 @@
 #include "ioctl.h"
 #include "print-tree.h"
 #include "xattr.h"
+#include "compat.h"

 #define BTRFS_SUPER_MAGIC 0x9123683E

@@ -345,9 +346,9 @@ int btrfs_get_sb_bdev(struct file_system
 	 * will protect the lockfs code from trying to start a snapshot
 	 * while we are mounting
 	 */
- -	down(&bdev->bd_mount_sem);
+	bd_mount_sem_down(bdev);
 	s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
- -	up(&bdev->bd_mount_sem);
+	bd_mount_sem_up(bdev);
 	if (IS_ERR(s))
 		goto error_s;


- --
Jeff Mahoney
SUSE Labs
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On Wed, Feb 06, 2008 at 05:14:47PM -0500, Jeff Mahoney
wrote:
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>  Versions prior to 2.6.20 used mutexes for bd_mount_sem.
Yikes, please don't put all this compat crap in.  If you want to
backport it keep your patches somewhere.