*
* LIFETIME:
* Inode marks survive between when they are added to an inode and when their
- * refcnt==0.
+ * refcnt==0. Marks are also protected by fsnotify_mark_srcu.
*
* The inode mark can be cleared for a number of different reasons including:
* - The inode is unlinked for the last time. (fsnotify_inode_remove)
* - The fsnotify_group associated with the mark is going away and all such marks
* need to be cleaned up. (fsnotify_clear_marks_by_group)
*
- * Worst case we are given an inode and need to clean up all the marks on that
- * inode. We take i_lock and walk the i_fsnotify_marks safely. For each
- * mark on the list we take a reference (so the mark can't disappear under us).
- * We remove that mark form the inode's list of marks and we add this mark to a
- * private list anchored on the stack using i_free_list; we walk i_free_list
- * and before we destroy the mark we make sure that we dont race with a
- * concurrent destroy_group by getting a ref to the marks group and taking the
- * groups mutex.
-
- * Very similarly for freeing by group, except we use free_g_list.
- *
* This has the very interesting property of being able to run concurrently with
* any (or all) other directions.
*/
#define FSNOTIFY_REAPER_DELAY (1) /* 1 jiffy */
struct srcu_struct fsnotify_mark_srcu;
+struct kmem_cache *fsnotify_mark_connector_cachep;
+
static DEFINE_SPINLOCK(destroy_lock);
static LIST_HEAD(destroy_list);
}
}
-/* Calculate mask of events for a list of marks */
-u32 fsnotify_recalc_mask(struct hlist_head *head)
+static void __fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
{
u32 new_mask = 0;
struct fsnotify_mark *mark;
- hlist_for_each_entry(mark, head, obj_list)
+ hlist_for_each_entry(mark, &conn->list, obj_list)
new_mask |= mark->mask;
- return new_mask;
+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
+ conn->inode->i_fsnotify_mask = new_mask;
+ else if (conn->flags & FSNOTIFY_OBJ_TYPE_VFSMOUNT)
+ real_mount(conn->mnt)->mnt_fsnotify_mask = new_mask;
+}
+
+/*
+ * Calculate mask of events for a list of marks. The caller must make sure
+ * connector cannot disappear under us (usually by holding a mark->lock or
+ * mark->group->mark_mutex for a mark on this list).
+ */
+void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
+{
+ if (!conn)
+ return;
+
+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
+ spin_lock(&conn->inode->i_lock);
+ else
+ spin_lock(&conn->mnt->mnt_root->d_lock);
+ __fsnotify_recalc_mask(conn);
+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE) {
+ spin_unlock(&conn->inode->i_lock);
+ __fsnotify_update_child_dentry_flags(conn->inode);
+ } else {
+ spin_unlock(&conn->mnt->mnt_root->d_lock);
+ }
}
/*
mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED;
- if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) {
- inode = mark->inode;
- fsnotify_destroy_inode_mark(mark);
- } else if (mark->flags & FSNOTIFY_MARK_FLAG_VFSMOUNT)
+ if (mark->connector->flags & FSNOTIFY_OBJ_TYPE_INODE)
+ inode = fsnotify_destroy_inode_mark(mark);
+ else if (mark->connector->flags & FSNOTIFY_OBJ_TYPE_VFSMOUNT)
fsnotify_destroy_vfsmount_mark(mark);
else
BUG();
spin_unlock(&mark->lock);
- if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED))
+ if (inode)
iput(inode);
atomic_dec(&group->num_marks);
fsnotify_free_mark(mark);
}
-void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock)
+void fsnotify_connector_free(struct fsnotify_mark_connector **connp)
{
- struct fsnotify_mark *mark;
-
- while (1) {
- /*
- * We have to be careful since we can race with e.g.
- * fsnotify_clear_marks_by_group() and once we drop 'lock',
- * mark can get removed from the obj_list and destroyed. But
- * we are holding mark reference so mark cannot be freed and
- * calling fsnotify_destroy_mark() more than once is fine.
- */
- spin_lock(lock);
- if (hlist_empty(head)) {
- spin_unlock(lock);
- break;
- }
- mark = hlist_entry(head->first, struct fsnotify_mark, obj_list);
- /*
- * We don't update i_fsnotify_mask / mnt_fsnotify_mask here
- * since inode / mount is going away anyway. So just remove
- * mark from the list.
- */
- hlist_del_init_rcu(&mark->obj_list);
- fsnotify_get_mark(mark);
- spin_unlock(lock);
- fsnotify_destroy_mark(mark, mark->group);
- fsnotify_put_mark(mark);
+ if (*connp) {
+ kmem_cache_free(fsnotify_mark_connector_cachep, *connp);
+ *connp = NULL;
}
}
assert_spin_locked(&mark->lock);
mark->mask = mask;
-
- if (mark->flags & FSNOTIFY_MARK_FLAG_INODE)
- fsnotify_set_inode_mark_mask_locked(mark, mask);
}
void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask)
return -1;
}
-/* Add mark into proper place in given list of marks */
-int fsnotify_add_mark_list(struct hlist_head *head, struct fsnotify_mark *mark,
- int allow_dups)
+static int fsnotify_attach_connector_to_object(
+ struct fsnotify_mark_connector **connp,
+ spinlock_t *lock,
+ struct inode *inode,
+ struct vfsmount *mnt)
+{
+ struct fsnotify_mark_connector *conn;
+
+ conn = kmem_cache_alloc(fsnotify_mark_connector_cachep, GFP_KERNEL);
+ if (!conn)
+ return -ENOMEM;
+ INIT_HLIST_HEAD(&conn->list);
+ if (inode) {
+ conn->flags = FSNOTIFY_OBJ_TYPE_INODE;
+ conn->inode = inode;
+ } else {
+ conn->flags = FSNOTIFY_OBJ_TYPE_VFSMOUNT;
+ conn->mnt = mnt;
+ }
+ /*
+ * Make sure 'conn' initialization is visible. Matches
+ * lockless_dereference() in fsnotify().
+ */
+ smp_wmb();
+ spin_lock(lock);
+ if (!*connp)
+ *connp = conn;
+ else
+ kmem_cache_free(fsnotify_mark_connector_cachep, conn);
+ spin_unlock(lock);
+
+ return 0;
+}
+
+/*
+ * Add mark into proper place in given list of marks. These marks may be used
+ * for the fsnotify backend to determine which event types should be delivered
+ * to which group and for which inodes. These marks are ordered according to
+ * priority, highest number first, and then by the group's location in memory.
+ */
+static int fsnotify_add_mark_list(struct fsnotify_mark *mark,
+ struct inode *inode, struct vfsmount *mnt,
+ int allow_dups)
{
struct fsnotify_mark *lmark, *last = NULL;
+ struct fsnotify_mark_connector *conn;
+ struct fsnotify_mark_connector **connp;
+ spinlock_t *lock;
int cmp;
+ int err = 0;
+
+ if (WARN_ON(!inode && !mnt))
+ return -EINVAL;
+ if (inode) {
+ connp = &inode->i_fsnotify_marks;
+ lock = &inode->i_lock;
+ } else {
+ connp = &real_mount(mnt)->mnt_fsnotify_marks;
+ lock = &mnt->mnt_root->d_lock;
+ }
+
+ if (!*connp) {
+ err = fsnotify_attach_connector_to_object(connp, lock,
+ inode, mnt);
+ if (err)
+ return err;
+ }
+ spin_lock(&mark->lock);
+ spin_lock(lock);
+ conn = *connp;
/* is mark the first mark? */
- if (hlist_empty(head)) {
- hlist_add_head_rcu(&mark->obj_list, head);
- return 0;
+ if (hlist_empty(&conn->list)) {
+ hlist_add_head_rcu(&mark->obj_list, &conn->list);
+ if (inode)
+ __iget(inode);
+ goto added;
}
/* should mark be in the middle of the current list? */
- hlist_for_each_entry(lmark, head, obj_list) {
+ hlist_for_each_entry(lmark, &conn->list, obj_list) {
last = lmark;
- if ((lmark->group == mark->group) && !allow_dups)
- return -EEXIST;
+ if ((lmark->group == mark->group) && !allow_dups) {
+ err = -EEXIST;
+ goto out_err;
+ }
cmp = fsnotify_compare_groups(lmark->group, mark->group);
if (cmp >= 0) {
hlist_add_before_rcu(&mark->obj_list, &lmark->obj_list);
- return 0;
+ goto added;
}
}
BUG_ON(last == NULL);
/* mark should be the last entry. last is the current last entry */
hlist_add_behind_rcu(&mark->obj_list, &last->obj_list);
- return 0;
+added:
+ mark->connector = conn;
+out_err:
+ spin_unlock(lock);
+ spin_unlock(&mark->lock);
+ return err;
}
/*
list_add(&mark->g_list, &group->marks_list);
atomic_inc(&group->num_marks);
fsnotify_get_mark(mark); /* for i_list and g_list */
-
- if (inode) {
- ret = fsnotify_add_inode_mark(mark, group, inode, allow_dups);
- if (ret)
- goto err;
- } else if (mnt) {
- ret = fsnotify_add_vfsmount_mark(mark, group, mnt, allow_dups);
- if (ret)
- goto err;
- } else {
- BUG();
- }
-
- /* this will pin the object if appropriate */
- fsnotify_set_mark_mask_locked(mark, mark->mask);
spin_unlock(&mark->lock);
- if (inode)
- __fsnotify_update_child_dentry_flags(inode);
+ ret = fsnotify_add_mark_list(mark, inode, mnt, allow_dups);
+ if (ret)
+ goto err;
+
+ if (mark->mask)
+ fsnotify_recalc_mask(mark->connector);
return ret;
err:
* Given a list of marks, find the mark associated with given group. If found
* take a reference to that mark and return it, else return NULL.
*/
-struct fsnotify_mark *fsnotify_find_mark(struct hlist_head *head,
+struct fsnotify_mark *fsnotify_find_mark(struct fsnotify_mark_connector *conn,
struct fsnotify_group *group)
{
struct fsnotify_mark *mark;
+ spinlock_t *lock;
+
+ if (!conn)
+ return NULL;
- hlist_for_each_entry(mark, head, obj_list) {
+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
+ lock = &conn->inode->i_lock;
+ else
+ lock = &conn->mnt->mnt_root->d_lock;
+ spin_lock(lock);
+ hlist_for_each_entry(mark, &conn->list, obj_list) {
if (mark->group == group) {
fsnotify_get_mark(mark);
+ spin_unlock(lock);
return mark;
}
}
+ spin_unlock(lock);
return NULL;
}
*/
mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) {
- if (mark->flags & flags)
+ if (mark->connector->flags & flags)
list_move(&mark->g_list, &to_free);
}
mutex_unlock(&group->mark_mutex);
}
}
+void fsnotify_destroy_marks(struct fsnotify_mark_connector *conn,
+ spinlock_t *lock)
+{
+ struct fsnotify_mark *mark;
+
+ if (!conn)
+ return;
+
+ while (1) {
+ /*
+ * We have to be careful since we can race with e.g.
+ * fsnotify_clear_marks_by_group() and once we drop 'lock',
+ * mark can get removed from the obj_list and destroyed. But
+ * we are holding mark reference so mark cannot be freed and
+ * calling fsnotify_destroy_mark() more than once is fine.
+ */
+ spin_lock(lock);
+ if (hlist_empty(&conn->list)) {
+ spin_unlock(lock);
+ break;
+ }
+ mark = hlist_entry(conn->list.first, struct fsnotify_mark,
+ obj_list);
+ /*
+ * We don't update i_fsnotify_mask / mnt_fsnotify_mask here
+ * since inode / mount is going away anyway. So just remove
+ * mark from the list.
+ */
+ hlist_del_init_rcu(&mark->obj_list);
+ fsnotify_get_mark(mark);
+ spin_unlock(lock);
+ fsnotify_destroy_mark(mark, mark->group);
+ fsnotify_put_mark(mark);
+ }
+}
+
/*
* Nothing fancy, just initialize lists and locks and counters.
*/
git.samba.org / sfrench / cifs-2.6.git / blobdiff