diff options
Diffstat (limited to 'fs/notify/mark.c')
-rw-r--r-- | fs/notify/mark.c | 178 |
1 files changed, 122 insertions, 56 deletions
diff --git a/fs/notify/mark.c b/fs/notify/mark.c index 1d96216dffd1..c74ef947447d 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -116,20 +116,64 @@ __u32 fsnotify_conn_mask(struct fsnotify_mark_connector *conn) return *fsnotify_conn_mask_p(conn); } -static void __fsnotify_recalc_mask(struct fsnotify_mark_connector *conn) +static void fsnotify_get_inode_ref(struct inode *inode) +{ + ihold(inode); + atomic_long_inc(&inode->i_sb->s_fsnotify_connectors); +} + +/* + * Grab or drop inode reference for the connector if needed. + * + * When it's time to drop the reference, we only clear the HAS_IREF flag and + * return the inode object. fsnotify_drop_object() will be resonsible for doing + * iput() outside of spinlocks. This happens when last mark that wanted iref is + * detached. + */ +static struct inode *fsnotify_update_iref(struct fsnotify_mark_connector *conn, + bool want_iref) +{ + bool has_iref = conn->flags & FSNOTIFY_CONN_FLAG_HAS_IREF; + struct inode *inode = NULL; + + if (conn->type != FSNOTIFY_OBJ_TYPE_INODE || + want_iref == has_iref) + return NULL; + + if (want_iref) { + /* Pin inode if any mark wants inode refcount held */ + fsnotify_get_inode_ref(fsnotify_conn_inode(conn)); + conn->flags |= FSNOTIFY_CONN_FLAG_HAS_IREF; + } else { + /* Unpin inode after detach of last mark that wanted iref */ + inode = fsnotify_conn_inode(conn); + conn->flags &= ~FSNOTIFY_CONN_FLAG_HAS_IREF; + } + + return inode; +} + +static void *__fsnotify_recalc_mask(struct fsnotify_mark_connector *conn) { u32 new_mask = 0; + bool want_iref = false; struct fsnotify_mark *mark; assert_spin_locked(&conn->lock); /* We can get detached connector here when inode is getting unlinked. */ if (!fsnotify_valid_obj_type(conn->type)) - return; + return NULL; hlist_for_each_entry(mark, &conn->list, obj_list) { - if (mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) - new_mask |= mark->mask; + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) + continue; + new_mask |= fsnotify_calc_mask(mark); + if (conn->type == FSNOTIFY_OBJ_TYPE_INODE && + !(mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF)) + want_iref = true; } *fsnotify_conn_mask_p(conn) = new_mask; + + return fsnotify_update_iref(conn, want_iref); } /* @@ -169,6 +213,31 @@ static void fsnotify_connector_destroy_workfn(struct work_struct *work) } } +static void fsnotify_put_inode_ref(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + + iput(inode); + if (atomic_long_dec_and_test(&sb->s_fsnotify_connectors)) + wake_up_var(&sb->s_fsnotify_connectors); +} + +static void fsnotify_get_sb_connectors(struct fsnotify_mark_connector *conn) +{ + struct super_block *sb = fsnotify_connector_sb(conn); + + if (sb) + atomic_long_inc(&sb->s_fsnotify_connectors); +} + +static void fsnotify_put_sb_connectors(struct fsnotify_mark_connector *conn) +{ + struct super_block *sb = fsnotify_connector_sb(conn); + + if (sb && atomic_long_dec_and_test(&sb->s_fsnotify_connectors)) + wake_up_var(&sb->s_fsnotify_connectors); +} + static void *fsnotify_detach_connector_from_object( struct fsnotify_mark_connector *conn, unsigned int *type) @@ -182,13 +251,17 @@ static void *fsnotify_detach_connector_from_object( if (conn->type == FSNOTIFY_OBJ_TYPE_INODE) { inode = fsnotify_conn_inode(conn); inode->i_fsnotify_mask = 0; - atomic_long_inc(&inode->i_sb->s_fsnotify_inode_refs); + + /* Unpin inode when detaching from connector */ + if (!(conn->flags & FSNOTIFY_CONN_FLAG_HAS_IREF)) + inode = NULL; } else if (conn->type == FSNOTIFY_OBJ_TYPE_VFSMOUNT) { fsnotify_conn_mount(conn)->mnt_fsnotify_mask = 0; } else if (conn->type == FSNOTIFY_OBJ_TYPE_SB) { fsnotify_conn_sb(conn)->s_fsnotify_mask = 0; } + fsnotify_put_sb_connectors(conn); rcu_assign_pointer(*(conn->obj), NULL); conn->obj = NULL; conn->type = FSNOTIFY_OBJ_TYPE_DETACHED; @@ -209,19 +282,12 @@ static void fsnotify_final_mark_destroy(struct fsnotify_mark *mark) /* Drop object reference originally held by a connector */ static void fsnotify_drop_object(unsigned int type, void *objp) { - struct inode *inode; - struct super_block *sb; - if (!objp) return; /* Currently only inode references are passed to be dropped */ if (WARN_ON_ONCE(type != FSNOTIFY_OBJ_TYPE_INODE)) return; - inode = objp; - sb = inode->i_sb; - iput(inode); - if (atomic_long_dec_and_test(&sb->s_fsnotify_inode_refs)) - wake_up_var(&sb->s_fsnotify_inode_refs); + fsnotify_put_inode_ref(objp); } void fsnotify_put_mark(struct fsnotify_mark *mark) @@ -250,7 +316,8 @@ void fsnotify_put_mark(struct fsnotify_mark *mark) objp = fsnotify_detach_connector_from_object(conn, &type); free_conn = true; } else { - __fsnotify_recalc_mask(conn); + objp = __fsnotify_recalc_mask(conn); + type = conn->type; } WRITE_ONCE(mark->connector, NULL); spin_unlock(&conn->lock); @@ -325,13 +392,16 @@ static void fsnotify_put_mark_wake(struct fsnotify_mark *mark) } bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info) + __releases(&fsnotify_mark_srcu) { int type; - fsnotify_foreach_obj_type(type) { + fsnotify_foreach_iter_type(type) { /* This can fail if mark is being removed */ - if (!fsnotify_get_mark_safe(iter_info->marks[type])) + if (!fsnotify_get_mark_safe(iter_info->marks[type])) { + __release(&fsnotify_mark_srcu); goto fail; + } } /* @@ -350,11 +420,12 @@ fail: } void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info) + __acquires(&fsnotify_mark_srcu) { int type; iter_info->srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); - fsnotify_foreach_obj_type(type) + fsnotify_foreach_iter_type(type) fsnotify_put_mark_wake(iter_info->marks[type]); } @@ -370,9 +441,7 @@ void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info) */ void fsnotify_detach_mark(struct fsnotify_mark *mark) { - struct fsnotify_group *group = mark->group; - - WARN_ON_ONCE(!mutex_is_locked(&group->mark_mutex)); + fsnotify_group_assert_locked(mark->group); WARN_ON_ONCE(!srcu_read_lock_held(&fsnotify_mark_srcu) && refcount_read(&mark->refcnt) < 1 + !!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)); @@ -387,8 +456,6 @@ void fsnotify_detach_mark(struct fsnotify_mark *mark) list_del_init(&mark->g_list); spin_unlock(&mark->lock); - atomic_dec(&group->num_marks); - /* Drop mark reference acquired in fsnotify_add_mark_locked() */ fsnotify_put_mark(mark); } @@ -426,9 +493,9 @@ void fsnotify_free_mark(struct fsnotify_mark *mark) void fsnotify_destroy_mark(struct fsnotify_mark *mark, struct fsnotify_group *group) { - mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); + fsnotify_group_lock(group); fsnotify_detach_mark(mark); - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); fsnotify_free_mark(mark); } EXPORT_SYMBOL_GPL(fsnotify_destroy_mark); @@ -470,10 +537,9 @@ int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b) } static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp, - unsigned int type, + unsigned int obj_type, __kernel_fsid_t *fsid) { - struct inode *inode = NULL; struct fsnotify_mark_connector *conn; conn = kmem_cache_alloc(fsnotify_mark_connector_cachep, GFP_KERNEL); @@ -481,7 +547,8 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp, return -ENOMEM; spin_lock_init(&conn->lock); INIT_HLIST_HEAD(&conn->list); - conn->type = type; + conn->flags = 0; + conn->type = obj_type; conn->obj = connp; /* Cache fsid of filesystem containing the object */ if (fsid) { @@ -491,16 +558,15 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp, conn->fsid.val[0] = conn->fsid.val[1] = 0; conn->flags = 0; } - if (conn->type == FSNOTIFY_OBJ_TYPE_INODE) - inode = igrab(fsnotify_conn_inode(conn)); + fsnotify_get_sb_connectors(conn); + /* * cmpxchg() provides the barrier so that readers of *connp can see * only initialized structure */ if (cmpxchg(connp, NULL, conn)) { /* Someone else created list structure for us */ - if (inode) - iput(inode); + fsnotify_put_sb_connectors(conn); kmem_cache_free(fsnotify_mark_connector_cachep, conn); } @@ -541,15 +607,16 @@ out: * priority, highest number first, and then by the group's location in memory. */ static int fsnotify_add_mark_list(struct fsnotify_mark *mark, - fsnotify_connp_t *connp, unsigned int type, - int allow_dups, __kernel_fsid_t *fsid) + fsnotify_connp_t *connp, + unsigned int obj_type, + int add_flags, __kernel_fsid_t *fsid) { struct fsnotify_mark *lmark, *last = NULL; struct fsnotify_mark_connector *conn; int cmp; int err = 0; - if (WARN_ON(!fsnotify_valid_obj_type(type))) + if (WARN_ON(!fsnotify_valid_obj_type(obj_type))) return -EINVAL; /* Backend is expected to check for zero fsid (e.g. tmpfs) */ @@ -561,7 +628,8 @@ restart: conn = fsnotify_grab_connector(connp); if (!conn) { spin_unlock(&mark->lock); - err = fsnotify_attach_connector_to_object(connp, type, fsid); + err = fsnotify_attach_connector_to_object(connp, obj_type, + fsid); if (err) return err; goto restart; @@ -600,7 +668,7 @@ restart: if ((lmark->group == mark->group) && (lmark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) && - !allow_dups) { + !(mark->group->flags & FSNOTIFY_GROUP_DUPS)) { err = -EEXIST; goto out_err; } @@ -634,13 +702,13 @@ out_err: * event types should be delivered to which group. */ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, - fsnotify_connp_t *connp, unsigned int type, - int allow_dups, __kernel_fsid_t *fsid) + fsnotify_connp_t *connp, unsigned int obj_type, + int add_flags, __kernel_fsid_t *fsid) { struct fsnotify_group *group = mark->group; int ret = 0; - BUG_ON(!mutex_is_locked(&group->mark_mutex)); + fsnotify_group_assert_locked(group); /* * LOCKING ORDER!!!! @@ -652,16 +720,14 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_ATTACHED; list_add(&mark->g_list, &group->marks_list); - atomic_inc(&group->num_marks); fsnotify_get_mark(mark); /* for g_list */ spin_unlock(&mark->lock); - ret = fsnotify_add_mark_list(mark, connp, type, allow_dups, fsid); + ret = fsnotify_add_mark_list(mark, connp, obj_type, add_flags, fsid); if (ret) goto err; - if (mark->mask) - fsnotify_recalc_mask(mark->connector); + fsnotify_recalc_mask(mark->connector); return ret; err: @@ -670,21 +736,21 @@ err: FSNOTIFY_MARK_FLAG_ATTACHED); list_del_init(&mark->g_list); spin_unlock(&mark->lock); - atomic_dec(&group->num_marks); fsnotify_put_mark(mark); return ret; } int fsnotify_add_mark(struct fsnotify_mark *mark, fsnotify_connp_t *connp, - unsigned int type, int allow_dups, __kernel_fsid_t *fsid) + unsigned int obj_type, int add_flags, + __kernel_fsid_t *fsid) { int ret; struct fsnotify_group *group = mark->group; - mutex_lock(&group->mark_mutex); - ret = fsnotify_add_mark_locked(mark, connp, type, allow_dups, fsid); - mutex_unlock(&group->mark_mutex); + fsnotify_group_lock(group); + ret = fsnotify_add_mark_locked(mark, connp, obj_type, add_flags, fsid); + fsnotify_group_unlock(group); return ret; } EXPORT_SYMBOL_GPL(fsnotify_add_mark); @@ -718,14 +784,14 @@ EXPORT_SYMBOL_GPL(fsnotify_find_mark); /* Clear any marks in a group with given type mask */ void fsnotify_clear_marks_by_group(struct fsnotify_group *group, - unsigned int type_mask) + unsigned int obj_type) { struct fsnotify_mark *lmark, *mark; LIST_HEAD(to_free); struct list_head *head = &to_free; /* Skip selection step if we want to clear all marks. */ - if (type_mask == FSNOTIFY_OBJ_ALL_TYPES_MASK) { + if (obj_type == FSNOTIFY_OBJ_TYPE_ANY) { head = &group->marks_list; goto clear; } @@ -738,24 +804,24 @@ void fsnotify_clear_marks_by_group(struct fsnotify_group *group, * move marks to free to to_free list in one go and then free marks in * to_free list one by one. */ - mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); + fsnotify_group_lock(group); list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) { - if ((1U << mark->connector->type) & type_mask) + if (mark->connector->type == obj_type) list_move(&mark->g_list, &to_free); } - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); clear: while (1) { - mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); + fsnotify_group_lock(group); if (list_empty(head)) { - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); break; } mark = list_first_entry(head, struct fsnotify_mark, g_list); fsnotify_get_mark(mark); fsnotify_detach_mark(mark); - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); fsnotify_free_mark(mark); fsnotify_put_mark(mark); } |