On Tue, 2007-01-09 at 15:49 +1100, David Chinner wrote: > On Tue, Jan 09, 2007 at 03:17:03PM +1100, Nathan Scott wrote: > > On Mon, 2007-01-08 at 19:51 -0800, Andrew Morton wrote: > > > If that's not true, then what _is_ happening in there? > > > > This particular case was a device mapper stack trace, hence the > > confusion, I think. Both XFS and DM are making the same generic > > block layer call here though (freeze_bdev). > > Yup. it's the freeze_bdev/thaw_bdev use of the bd_mount_mutex() > that's the problem. I fail to see _why_ we need to hold a lock > across the freeze/thaw - the only reason i can think of is to > hold out new calls to sget() (via get_sb_bdev()) while the > filesystem is frozen though I'm not sure why you'd need to > do that. Can someone explain why we are holding the lock from > freeze to thaw? Not me. If it's really not needed, then... > > > If that _is_ true then, well, that sucks a bit. > > > > Indeed, its a fairly ordinary interface, but thats too late to go > > fix now I guess (since its exposed to userspace already). > > Userspace knows nothing about that lock, so we can change that without > changing the the userspace API. ...that would be true, AFAICS. cheers. -- Nathan - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
- References:
- Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock()
- From: David Chinner <[email protected]>
- Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock()
- From: Sami Farin <[email protected]>
- Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock()
- From: Eric Sandeen <[email protected]>
- bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())
- From: David Chinner <[email protected]>
- Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())
- From: Andrew Morton <[email protected]>
- Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())
- From: Eric Sandeen <[email protected]>
- Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())
- From: Andrew Morton <[email protected]>
- Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())
- From: Eric Sandeen <[email protected]>
- Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())
- From: Andrew Morton <[email protected]>
- Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())
- From: Nathan Scott <[email protected]>
- Re: bd_mount_mutex -> bd_mount_sem (was Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock())
- From: David Chinner <[email protected]>
- Re: xfs_file_ioctl / xfs_freeze: BUG: warning at kernel/mutex-debug.c:80/debug_mutex_unlock()
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