diff options
Diffstat (limited to 'fs/notify/mark.c')
| -rw-r--r-- | fs/notify/mark.c | 54 |
1 files changed, 41 insertions, 13 deletions
diff --git a/fs/notify/mark.c b/fs/notify/mark.c index d2dd16cb5989..22acb0a79b53 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -82,6 +82,7 @@ #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/srcu.h> +#include <linux/ratelimit.h> #include <linux/atomic.h> @@ -238,13 +239,13 @@ static void fsnotify_drop_object(unsigned int type, void *objp) void fsnotify_put_mark(struct fsnotify_mark *mark) { - struct fsnotify_mark_connector *conn; + struct fsnotify_mark_connector *conn = READ_ONCE(mark->connector); void *objp = NULL; unsigned int type = FSNOTIFY_OBJ_TYPE_DETACHED; bool free_conn = false; /* Catch marks that were actually never attached to object */ - if (!mark->connector) { + if (!conn) { if (refcount_dec_and_test(&mark->refcnt)) fsnotify_final_mark_destroy(mark); return; @@ -254,10 +255,9 @@ void fsnotify_put_mark(struct fsnotify_mark *mark) * We have to be careful so that traversals of obj_list under lock can * safely grab mark reference. */ - if (!refcount_dec_and_lock(&mark->refcnt, &mark->connector->lock)) + if (!refcount_dec_and_lock(&mark->refcnt, &conn->lock)) return; - conn = mark->connector; hlist_del_init_rcu(&mark->obj_list); if (hlist_empty(&conn->list)) { objp = fsnotify_detach_connector_from_object(conn, &type); @@ -265,7 +265,7 @@ void fsnotify_put_mark(struct fsnotify_mark *mark) } else { __fsnotify_recalc_mask(conn); } - mark->connector = NULL; + WRITE_ONCE(mark->connector, NULL); spin_unlock(&conn->lock); fsnotify_drop_object(type, objp); @@ -481,7 +481,8 @@ 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 type, + __kernel_fsid_t *fsid) { struct inode *inode = NULL; struct fsnotify_mark_connector *conn; @@ -493,6 +494,11 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp, INIT_HLIST_HEAD(&conn->list); conn->type = type; conn->obj = connp; + /* Cache fsid of filesystem containing the object */ + if (fsid) + conn->fsid = *fsid; + else + conn->fsid.val[0] = conn->fsid.val[1] = 0; if (conn->type == FSNOTIFY_OBJ_TYPE_INODE) inode = igrab(fsnotify_conn_inode(conn)); /* @@ -544,7 +550,7 @@ out: */ static int fsnotify_add_mark_list(struct fsnotify_mark *mark, fsnotify_connp_t *connp, unsigned int type, - int allow_dups) + int allow_dups, __kernel_fsid_t *fsid) { struct fsnotify_mark *lmark, *last = NULL; struct fsnotify_mark_connector *conn; @@ -553,15 +559,36 @@ static int fsnotify_add_mark_list(struct fsnotify_mark *mark, if (WARN_ON(!fsnotify_valid_obj_type(type))) return -EINVAL; + + /* Backend is expected to check for zero fsid (e.g. tmpfs) */ + if (fsid && WARN_ON_ONCE(!fsid->val[0] && !fsid->val[1])) + return -ENODEV; + restart: spin_lock(&mark->lock); conn = fsnotify_grab_connector(connp); if (!conn) { spin_unlock(&mark->lock); - err = fsnotify_attach_connector_to_object(connp, type); + err = fsnotify_attach_connector_to_object(connp, type, fsid); if (err) return err; goto restart; + } else if (fsid && (conn->fsid.val[0] || conn->fsid.val[1]) && + (fsid->val[0] != conn->fsid.val[0] || + fsid->val[1] != conn->fsid.val[1])) { + /* + * Backend is expected to check for non uniform fsid + * (e.g. btrfs), but maybe we missed something? + * Only allow setting conn->fsid once to non zero fsid. + * inotify and non-fid fanotify groups do not set nor test + * conn->fsid. + */ + pr_warn_ratelimited("%s: fsid mismatch on object of type %u: " + "%x.%x != %x.%x\n", __func__, conn->type, + fsid->val[0], fsid->val[1], + conn->fsid.val[0], conn->fsid.val[1]); + err = -EXDEV; + goto out_err; } /* is mark the first mark? */ @@ -592,7 +619,7 @@ restart: /* mark should be the last entry. last is the current last entry */ hlist_add_behind_rcu(&mark->obj_list, &last->obj_list); added: - mark->connector = conn; + WRITE_ONCE(mark->connector, conn); out_err: spin_unlock(&conn->lock); spin_unlock(&mark->lock); @@ -606,7 +633,7 @@ out_err: */ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, fsnotify_connp_t *connp, unsigned int type, - int allow_dups) + int allow_dups, __kernel_fsid_t *fsid) { struct fsnotify_group *group = mark->group; int ret = 0; @@ -627,7 +654,7 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, fsnotify_get_mark(mark); /* for g_list */ spin_unlock(&mark->lock); - ret = fsnotify_add_mark_list(mark, connp, type, allow_dups); + ret = fsnotify_add_mark_list(mark, connp, type, allow_dups, fsid); if (ret) goto err; @@ -648,13 +675,13 @@ err: } int fsnotify_add_mark(struct fsnotify_mark *mark, fsnotify_connp_t *connp, - unsigned int type, int allow_dups) + unsigned int type, int allow_dups, __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); + ret = fsnotify_add_mark_locked(mark, connp, type, allow_dups, fsid); mutex_unlock(&group->mark_mutex); return ret; } @@ -780,6 +807,7 @@ void fsnotify_init_mark(struct fsnotify_mark *mark, refcount_set(&mark->refcnt, 1); fsnotify_get_group(group); mark->group = group; + WRITE_ONCE(mark->connector, NULL); } /* |