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

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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: peterz@infradead.org
CC: mingo@redhat.com
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
This commit is contained in:
Jan Kara 2009-06-04 15:26:49 +02:00 • committed by Joel Becker
commit 9a7aa12f39
2 changed files with 26 additions and 6 deletions
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17
fs/inode.c
View file

@ -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;
/*
* 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);
/* 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);
}
}
#endif
/*

15
include/linux/lockdep.h
View file

@ -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)