fsnotify: use a mutex instead of a spinlock to protect a groups mark list

Replaces the groups mark_lock spinlock with a mutex. Using a mutex instead
of a spinlock results in more flexibility (i.e it allows to sleep while the
lock is held).

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>

diff --git a/fs/notify/group.c b/fs/notify/group.c
index 354044c47e23f23800bb34aad9e46b4edebc2418..1f7305711fc96dac2d97d4fa6b8edf6b84967c5c 100644 (file)
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -95,7 +95,7 @@ struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
        init_waitqueue_head(&group->notification_waitq);
        group->max_events = UINT_MAX;
 
-       spin_lock_init(&group->mark_lock);
+       mutex_init(&group->mark_mutex);
        INIT_LIST_HEAD(&group->marks_list);
 
        group->ops = ops;

diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index b13c00ac48eb377086f1928d8ff0cffae3b8cc44..4e9071e37d5da6948f62dbf21b2d8ba37ab057ad 100644 (file)
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -63,8 +63,8 @@ void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark)
 {
        struct inode *inode = mark->i.inode;
 
+       BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));
        assert_spin_locked(&mark->lock);
-       assert_spin_locked(&mark->group->mark_lock);
 
        spin_lock(&inode->i_lock);
 
@@ -191,8 +191,8 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
 
        mark->flags |= FSNOTIFY_MARK_FLAG_INODE;
 
+       BUG_ON(!mutex_is_locked(&group->mark_mutex));
        assert_spin_locked(&mark->lock);
-       assert_spin_locked(&group->mark_lock);
 
        spin_lock(&inode->i_lock);
 

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 32447dc06c07fc04a1b5ae15bb6d5172816cb6e3..ab25b810b14670f42d1771a65a0a52a0e614618e 100644 (file)
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -136,13 +136,13 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark)
        group = mark->group;
        spin_unlock(&mark->lock);
 
-       spin_lock(&group->mark_lock);
+       mutex_lock(&group->mark_mutex);
        spin_lock(&mark->lock);
 
        /* something else already called this function on this mark */
        if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {
                spin_unlock(&mark->lock);
-               spin_unlock(&group->mark_lock);
+               mutex_unlock(&group->mark_mutex);
                goto put_group;
        }
 
@@ -159,7 +159,7 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark)
        list_del_init(&mark->g_list);
 
        spin_unlock(&mark->lock);
-       spin_unlock(&group->mark_lock);
+       mutex_unlock(&group->mark_mutex);
 
        spin_lock(&destroy_lock);
        list_add(&mark->destroy_list, &destroy_list);
@@ -232,11 +232,11 @@ int fsnotify_add_mark(struct fsnotify_mark *mark,
 
        /*
         * LOCKING ORDER!!!!
-        * group->mark_lock
+        * group->mark_mutex
         * mark->lock
         * inode->i_lock
         */
-       spin_lock(&group->mark_lock);
+       mutex_lock(&group->mark_mutex);
 
        spin_lock(&mark->lock);
        mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE;
@@ -263,7 +263,7 @@ int fsnotify_add_mark(struct fsnotify_mark *mark,
        fsnotify_set_mark_mask_locked(mark, mark->mask);
        spin_unlock(&mark->lock);
 
-       spin_unlock(&group->mark_lock);
+       mutex_unlock(&group->mark_mutex);
 
        if (inode)
                __fsnotify_update_child_dentry_flags(inode);
@@ -277,7 +277,7 @@ err:
        atomic_dec(&group->num_marks);
 
        spin_unlock(&mark->lock);
-       spin_unlock(&group->mark_lock);
+       mutex_unlock(&group->mark_mutex);
 
        spin_lock(&destroy_lock);
        list_add(&mark->destroy_list, &destroy_list);
@@ -296,7 +296,7 @@ void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group,
        struct fsnotify_mark *lmark, *mark;
        LIST_HEAD(free_list);
 
-       spin_lock(&group->mark_lock);
+       mutex_lock(&group->mark_mutex);
        list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) {
                if (mark->flags & flags) {
                        list_add(&mark->free_g_list, &free_list);
@@ -304,7 +304,7 @@ void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group,
                        fsnotify_get_mark(mark);
                }
        }
-       spin_unlock(&group->mark_lock);
+       mutex_unlock(&group->mark_mutex);
 
        list_for_each_entry_safe(mark, lmark, &free_list, free_g_list) {
                fsnotify_destroy_mark(mark);

diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c
index b7b4b0e8554fb1e8ab6948f2efd35704ed156e56..f26a348827f80a1ac916c696d95745a87197c73e 100644 (file)
--- a/fs/notify/vfsmount_mark.c
+++ b/fs/notify/vfsmount_mark.c
@@ -88,8 +88,8 @@ void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark)
 {
        struct vfsmount *mnt = mark->m.mnt;
 
+       BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));
        assert_spin_locked(&mark->lock);
-       assert_spin_locked(&mark->group->mark_lock);
 
        spin_lock(&mnt->mnt_root->d_lock);
 
@@ -151,8 +151,8 @@ int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
 
        mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
 
+       BUG_ON(!mutex_is_locked(&group->mark_mutex));
        assert_spin_locked(&mark->lock);
-       assert_spin_locked(&group->mark_lock);
 
        spin_lock(&mnt->mnt_root->d_lock);
 

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index e76cef75295ddc4dc75b1b5d44d46d2b7db736f6..c5848346840daed5442d278316daa94c12f3d3ac 100644 (file)
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -141,7 +141,7 @@ struct fsnotify_group {
        unsigned int priority;
 
        /* stores all fastpath marks assoc with this group so they can be cleaned on unregister */
-       spinlock_t mark_lock;           /* protect marks_list */
+       struct mutex mark_mutex;        /* protect marks_list */
        atomic_t num_marks;             /* 1 for each mark and 1 for not being
                                         * past the point of no return when freeing
                                         * a group */