There is no need to use a special mutex to protect against the fcntl/close race (see dnotify.c for a description of this race). Instead the dnotify_groups mark mutex can be used.
Signed-off-by: Lino Sanfilippo <[email protected]> --- fs/notify/dnotify/dnotify.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index 2bfe6dc..1fedd5f 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -31,7 +31,6 @@ int dir_notify_enable __read_mostly = 1; static struct kmem_cache *dnotify_struct_cache __read_mostly; static struct kmem_cache *dnotify_mark_cache __read_mostly; static struct fsnotify_group *dnotify_group __read_mostly; -static DEFINE_MUTEX(dnotify_mark_mutex); /* * dnotify will attach one of these to each inode (i_fsnotify_marks) which @@ -183,7 +182,7 @@ void dnotify_flush(struct file *filp, fl_owner_t id) return; dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); - mutex_lock(&dnotify_mark_mutex); + mutex_lock(&dnotify_group->mark_mutex); spin_lock(&fsn_mark->lock); prev = &dn_mark->dn; @@ -199,11 +198,12 @@ void dnotify_flush(struct file *filp, fl_owner_t id) spin_unlock(&fsn_mark->lock); - /* nothing else could have found us thanks to the dnotify_mark_mutex */ + /* nothing else could have found us thanks to the dnotify_groups + mark_mutex */ if (dn_mark->dn == NULL) - fsnotify_destroy_mark(fsn_mark, dnotify_group); + fsnotify_destroy_mark_locked(fsn_mark, dnotify_group); - mutex_unlock(&dnotify_mark_mutex); + mutex_unlock(&dnotify_group->mark_mutex); fsnotify_put_mark(fsn_mark); } @@ -326,7 +326,7 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) new_dn_mark->dn = NULL; /* this is needed to prevent the fcntl/close race described below */ - mutex_lock(&dnotify_mark_mutex); + mutex_lock(&dnotify_group->mark_mutex); /* add the new_fsn_mark or find an old one. */ fsn_mark = fsnotify_find_inode_mark(dnotify_group, inode); @@ -334,7 +334,8 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); spin_lock(&fsn_mark->lock); } else { - fsnotify_add_mark(new_fsn_mark, dnotify_group, inode, NULL, 0); + fsnotify_add_mark_locked(new_fsn_mark, dnotify_group, inode, + NULL, 0); spin_lock(&new_fsn_mark->lock); fsn_mark = new_fsn_mark; dn_mark = new_dn_mark; @@ -348,9 +349,9 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) /* if (f != filp) means that we lost a race and another task/thread * actually closed the fd we are still playing with before we grabbed - * the dnotify_mark_mutex and fsn_mark->lock. Since closing the fd is the - * only time we clean up the marks we need to get our mark off - * the list. */ + * the dnotify_groups mark_mutex and fsn_mark->lock. Since closing the + * fd is the only time we clean up the marks we need to get our mark + * off the list. */ if (f != filp) { /* if we added ourselves, shoot ourselves, it's possible that * the flush actually did shoot this fsn_mark. That's fine too @@ -385,9 +386,9 @@ out: spin_unlock(&fsn_mark->lock); if (destroy) - fsnotify_destroy_mark(fsn_mark, dnotify_group); + fsnotify_destroy_mark_locked(fsn_mark, dnotify_group); - mutex_unlock(&dnotify_mark_mutex); + mutex_unlock(&dnotify_group->mark_mutex); fsnotify_put_mark(fsn_mark); out_err: if (new_fsn_mark) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
