Commit 9a7aa12f authored by Jan Kara's avatar Jan Kara Committed by Joel Becker
Browse files

vfs: Set special lockdep map for dirs only if not set by fs 



Some filesystems need to set lockdep map for i_mutex differently for
different directories. For example OCFS2 has system directories (for
orphan inode tracking and for gathering all system files like journal
or quota files into a single place) which have different locking
locking rules than standard directories. For a filesystem setting
lockdep map is naturaly done when the inode is read but we have to
modify unlock_new_inode() not to overwrite the lockdep map the filesystem
has set.

Acked-by: default avatar <peterz@infradead.org>
CC: mingo@redhat.com
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
parent df152c24

fs/inode.c

+11 −6
Original line number Diff line number Diff line
@@ -665,12 +665,17 @@ void unlock_new_inode(struct inode *inode) 
	if (inode->i_mode & S_IFDIR) {

		struct file_system_type *type = inode->i_sb->s_type;



		/* Set new key only if filesystem hasn't already changed it */

		if (!lockdep_match_class(&inode->i_mutex,

		    &type->i_mutex_key)) {

			/*

			 * ensure nobody is actually holding i_mutex

			 */

			mutex_destroy(&inode->i_mutex);

			mutex_init(&inode->i_mutex);

		lockdep_set_class(&inode->i_mutex, &type->i_mutex_dir_key);

			lockdep_set_class(&inode->i_mutex,

					  &type->i_mutex_dir_key);

		}

	}

#endif

	/*

include/linux/lockdep.h

+15 −0
Original line number Diff line number Diff line
@@ -258,6 +258,16 @@ extern void lockdep_init_map(struct lockdep_map *lock, const char *name, 
#define lockdep_set_subclass(lock, sub)	\

		lockdep_init_map(&(lock)->dep_map, #lock, \

				 (lock)->dep_map.key, sub)

/*

 * Compare locking classes

 */

#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)



static inline int lockdep_match_key(struct lockdep_map *lock,

				    struct lock_class_key *key)

{

	return lock->key == key;

}



/*

 * Acquire a lock.
@@ -326,6 +336,11 @@ static inline void lockdep_on(void) 
#define lockdep_set_class_and_subclass(lock, key, sub) \

		do { (void)(key); } while (0)

#define lockdep_set_subclass(lock, sub)		do { } while (0)

/*

 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP

 * case since the result is not well defined and the caller should rather

 * #ifdef the call himself.

 */



# define INIT_LOCKDEP

# define lockdep_reset()		do { debug_locks = 1; } while (0)

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