On Tue, Jun 05, 2012 at 02:16:32PM -0400, Josef Bacik wrote: > Al pointed out that we can just toss out the old name on a device and add a > new one arbitrarily, so anybody who uses device->name in printk could > possibly use free'd memory. Instead of adding locking around all of this he > suggested doing it with RCU, so I've introduced a struct rcu_string that > does just that and have gone through and protected all accesses to > device->name that aren't under the uuid_mutex with rcu_read_lock(). This > protects us and I will use it for dealing with removing the device that we > used to mount the file system in a later patch. Thanks, > > Signed-off-by: Josef Bacik <jo...@redhat.com> > --- > fs/btrfs/check-integrity.c | 11 ++++- > fs/btrfs/disk-io.c | 14 +++++- > fs/btrfs/extent_io.c | 7 +++- > fs/btrfs/ioctl.c | 14 +++++- > fs/btrfs/scrub.c | 39 ++++++++++++++--- > fs/btrfs/volumes.c | 102 > ++++++++++++++++++++++++++++++++------------ > fs/btrfs/volumes.h | 2 +- > 7 files changed, 147 insertions(+), 42 deletions(-) > > diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c > index 9cebb1f..9f69855 100644 > --- a/fs/btrfs/check-integrity.c > +++ b/fs/btrfs/check-integrity.c > @@ -93,6 +93,7 @@ > #include "print-tree.h" > #include "locking.h" > #include "check-integrity.h" > +#include "rcu-string.h"
Not included in the patch. Besides, it seems to be a more general API that should not live inside btrfs directory. While searching for the rcu-string.h I found http://lkml.indiana.edu/hypermail/linux/kernel/1001.0/00911.html "Add rcustring ADT for RCU protected strings v2" @ 2010 doing (probably) the same. david -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
