[PATCH 1/8] vfs: remove lock and unlock functions for super block

[PATCH 1/8] vfs: remove lock and unlock functions for super block

[Marco Stornelli]

From: Marco Stornelli <marco.stornelli@gmail.com>

Remove lock_super and unlock_super from VFS.

Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
---

diff -Nurp linux-3.6-rc1-orig/fs/super.c linux-3.6-rc1/fs/super.c
--- linux-3.6-rc1-orig/fs/super.c	2012-08-16 09:37:35.000000000 +0200
+++ linux-3.6-rc1/fs/super.c	2012-08-16 09:43:46.000000000 +0200
@@ -186,15 +186,8 @@ static struct super_block *alloc_super(s
 		spin_lock_init(&s->s_inode_lru_lock);
 		INIT_LIST_HEAD(&s->s_mounts);
 		init_rwsem(&s->s_umount);
-		mutex_init(&s->s_lock);
 		lockdep_set_class(&s->s_umount, &type->s_umount_key);
 		/*
-		 * The locking rules for s_lock are up to the
-		 * filesystem. For example ext3fs has different
-		 * lock ordering than usbfs:
-		 */
-		lockdep_set_class(&s->s_lock, &type->s_lock_key);
-		/*
 		 * sget() can have s_umount recursion.
 		 *
 		 * When it cannot find a suitable sb, it allocates a new
@@ -400,22 +393,6 @@ bool grab_super_passive(struct super_blo
 	return false;
 }
 -/*
- * Superblock locking.  We really ought to get rid of these two.
- */
-void lock_super(struct super_block * sb)
-{
-	mutex_lock(&sb->s_lock);
-}
-
-void unlock_super(struct super_block * sb)
-{
-	mutex_unlock(&sb->s_lock);
-}
-
-EXPORT_SYMBOL(lock_super);
-EXPORT_SYMBOL(unlock_super);
-
 /**
  *	generic_shutdown_super	-	common helper for ->kill_sb()
  *	@sb: superblock to kill

diff -Nurp linux-3.6-rc1-orig/include/linux/fs.h linux-3.6-rc1/include/linux/fs.h
--- linux-3.6-rc1-orig/include/linux/fs.h	2012-08-16 11:38:42.000000000 +0200
+++ linux-3.6-rc1/include/linux/fs.h	2012-08-16 09:45:18.000000000 +0200
@@ -1504,7 +1504,6 @@ struct super_block {
 	unsigned long		s_magic;
 	struct dentry		*s_root;
 	struct rw_semaphore	s_umount;
-	struct mutex		s_lock;
 	int			s_count;
 	atomic_t		s_active;
 #ifdef CONFIG_SECURITY

Re: [PATCH 1/8] vfs: remove lock and unlock functions for super block

[Boaz Harrosh]

On 08/16/2012 12:59 PM, Marco Stornelli wrote:

> From: Marco Stornelli <marco.stornelli@gmail.com>
> 
> Remove lock_super and unlock_super from VFS.
> 
> Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>


You can't remove the lock here. After this patch the tree will
not compile, and will not be bisectable. You must move this patch
to be last.

Each patch should leave the tree compileable and with out any
regressions.

Boaz

> ---
> 
> diff -Nurp linux-3.6-rc1-orig/fs/super.c linux-3.6-rc1/fs/super.c
> --- linux-3.6-rc1-orig/fs/super.c	2012-08-16 09:37:35.000000000 +0200
> +++ linux-3.6-rc1/fs/super.c	2012-08-16 09:43:46.000000000 +0200
> @@ -186,15 +186,8 @@ static struct super_block *alloc_super(s
>  		spin_lock_init(&s->s_inode_lru_lock);
>  		INIT_LIST_HEAD(&s->s_mounts);
>  		init_rwsem(&s->s_umount);
> -		mutex_init(&s->s_lock);
>  		lockdep_set_class(&s->s_umount, &type->s_umount_key);
>  		/*
> -		 * The locking rules for s_lock are up to the
> -		 * filesystem. For example ext3fs has different
> -		 * lock ordering than usbfs:
> -		 */
> -		lockdep_set_class(&s->s_lock, &type->s_lock_key);
> -		/*
>  		 * sget() can have s_umount recursion.
>  		 *
>  		 * When it cannot find a suitable sb, it allocates a new
> @@ -400,22 +393,6 @@ bool grab_super_passive(struct super_blo
>  	return false;
>  }
>  -/*
> - * Superblock locking.  We really ought to get rid of these two.
> - */
> -void lock_super(struct super_block * sb)
> -{
> -	mutex_lock(&sb->s_lock);
> -}
> -
> -void unlock_super(struct super_block * sb)
> -{
> -	mutex_unlock(&sb->s_lock);
> -}
> -
> -EXPORT_SYMBOL(lock_super);
> -EXPORT_SYMBOL(unlock_super);
> -
>  /**
>   *	generic_shutdown_super	-	common helper for ->kill_sb()
>   *	@sb: superblock to kill
> 
> diff -Nurp linux-3.6-rc1-orig/include/linux/fs.h linux-3.6-rc1/include/linux/fs.h
> --- linux-3.6-rc1-orig/include/linux/fs.h	2012-08-16 11:38:42.000000000 +0200
> +++ linux-3.6-rc1/include/linux/fs.h	2012-08-16 09:45:18.000000000 +0200
> @@ -1504,7 +1504,6 @@ struct super_block {
>  	unsigned long		s_magic;
>  	struct dentry		*s_root;
>  	struct rw_semaphore	s_umount;
> -	struct mutex		s_lock;
>  	int			s_count;
>  	atomic_t		s_active;
>  #ifdef CONFIG_SECURITY

Re: [PATCH 1/8] vfs: remove lock and unlock functions for super block

[Marco Stornelli]

Il 16/08/2012 14:26, Boaz Harrosh ha scritto:
> On 08/16/2012 12:59 PM, Marco Stornelli wrote:
>
>> From: Marco Stornelli <marco.stornelli@gmail.com>
>>
>> Remove lock_super and unlock_super from VFS.
>>
>> Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
>
>
> You can't remove the lock here. After this patch the tree will
> not compile, and will not be bisectable. You must move this patch
> to be last.
>
> Each patch should leave the tree compileable and with out any
> regressions.
>
> Boaz
>

Yep, you're right. I'll resend it in the right order at the end of first 
review.

Thanks,

Marco