On Wed, 3 Jul 2013 16:12:27 -0400
"J. Bruce Fields" <bfields@xxxxxxxxxx> wrote:
> From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
>
> I_MUTEX_QUOTA is now just being used whenever we want to lock two
> non-directories. So the name isn't right. I_MUTEX_NONDIR2 isn't
> especially elegant but it's the best I could think of.
>
> Also fix some outdated documentation.
>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> ---
> fs/inode.c | 4 ++--
> include/linux/fs.h | 9 ++++++---
> 2 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 942451b..304db4c 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -988,10 +988,10 @@ void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
> {
> if (inode1 < inode2) {
> mutex_lock(&inode1->i_mutex);
> - mutex_lock_nested(&inode2->i_mutex, I_MUTEX_QUOTA);
> + mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
> } else {
> mutex_lock(&inode2->i_mutex);
> - mutex_lock_nested(&inode1->i_mutex, I_MUTEX_QUOTA);
> + mutex_lock_nested(&inode1->i_mutex, I_MUTEX_NONDIR2);
> }
> }
> EXPORT_SYMBOL(lock_two_nondirectories);
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 3258761..ec88235 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -620,10 +620,13 @@ static inline int inode_unhashed(struct inode *inode)
> * 0: the object of the current VFS operation
> * 1: parent
> * 2: child/target
> - * 3: quota file
> + * 3: xattr
> + * 4: second non-directory
> + * The last is for certain operations (such as rename) which lock two
> + * non-directories at once.
> *
> * The locking order between these classes is
> - * parent -> child -> normal -> xattr -> quota
> + * parent -> child -> normal -> xattr -> second non-directory
> */
> enum inode_i_mutex_lock_class
> {
> @@ -631,7 +634,7 @@ enum inode_i_mutex_lock_class
> I_MUTEX_PARENT,
> I_MUTEX_CHILD,
> I_MUTEX_XATTR,
> - I_MUTEX_QUOTA
> + I_MUTEX_NONDIR2
> };
>
> void lock_two_nondirectories(struct inode *, struct inode*);
Ugly name, but I'm not sure what to call it either. Wonder if it would
make sense to do some sort of SOURCE/TARGET lock class and rearrange
the code to take that into account? But, that's just bikeshedding, so...
Acked-by: Jeff Layton <jlayton@xxxxxxxxxx>
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