[xfs-masters] Re: + update-sb-s_frozen-when-freezing-read-only-mounted-device-too.patch added to -mm tree

["Akinobu Mita" <akinobu.mita@xxxxxxxxx>]

2007/10/5, David Chinner <dgc@xxxxxxx>:
> > This patch updates sb->s_frozen when freeze_bdev() is called for read-only
> > mounted device, too.
>
> IMO, this is wrong.
>
> By definition, a read only filesystem is the equivalent of a frozen
> filesystem. i.e. freezing a rw filesystem temporarily puts it into
> ro state until it is unfrozen. IOWs, freeze_bdev() should not return
> with the bd_mount_sem if it's a read only filesystem because
> it is a no-op and there's nothing for a thaw to do...

freeze_bdev() with read-only filesystem is not so pointless.
Because it can prevent from someone trying to remount read/write
while freezing. (freeze_bdev() takes s->s_umount, too if there is a
filesystem mounted on the device)

So I prefer to keep current behavior of freeze_bdev for read-only filesystem
in this patch.