Messages in this thread Patch in this message | | | Date | Thu, 22 May 2008 13:40:49 +0200 | From | Louis Rilling <> | Subject | [RFC][PATCH 1/4] Prepare i_mutex lockdep subclasses for locking of variable path lengths |
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Some filesystems, like configfs, need to lock more than two regular inodes recursively in a tree, which i_mutex lockdep subclasses do not permit.
This patch reorders the definitions (but not the semantics) of i_mutex lockdep sub-classes so that nested i_mutex locking can be done with sub-classes I_MUTEX_PARENT -> I_MUTEX_CHILD -> I_MUTEX_CHILD + 1 -> I_MUTEX_CHILD + 2 -> ... until MAX_LOCKDEP_SUBCLASSES - 1.
Signed-off-by: Louis Rilling <Louis.Rilling@kerlabs.com> --- include/linux/fs.h | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
Index: b/include/linux/fs.h =================================================================== --- a/include/linux/fs.h 2008-05-21 09:40:28.000000000 +0200 +++ b/include/linux/fs.h 2008-05-22 12:20:20.000000000 +0200 @@ -660,20 +660,23 @@ struct inode { * inode->i_mutex nesting subclasses for the lock validator: * * 0: the object of the current VFS operation - * 1: parent - * 2: child/target - * 3: quota file + * 1: xattrs + * 2: quota file + * 3: parent + * 4: child/target + * ...: lower-level children * * The locking order between these classes is - * parent -> child -> normal -> xattr -> quota + * parent -> child -> sub-children... -> normal -> xattr -> quota */ enum inode_i_mutex_lock_class { I_MUTEX_NORMAL, + I_MUTEX_XATTR, + I_MUTEX_QUOTA, I_MUTEX_PARENT, I_MUTEX_CHILD, - I_MUTEX_XATTR, - I_MUTEX_QUOTA + /* Reserved for variable paths of nested inode locks */ }; extern void inode_double_lock(struct inode *inode1, struct inode *inode2); -- Dr Louis Rilling Kerlabs Skype: louis.rilling Batiment Germanium Phone: (+33|0) 6 80 89 08 23 80 avenue des Buttes de Coesmes http://www.kerlabs.com/ 35700 Rennes
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