diff options
| -rw-r--r-- | fs/kernfs/dir.c | 139 | ||||
| -rw-r--r-- | include/linux/kernfs.h | 1 |
2 files changed, 53 insertions, 87 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index e565ec0..7f8afc1 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -181,38 +181,14 @@ void kernfs_put_active(struct kernfs_node *kn) * kernfs_drain - drain kernfs_node * @kn: kernfs_node to drain * - * Drain existing usages of @kn. Mutiple removers may invoke this function - * concurrently on @kn and all will return after draining is complete. - * Returns %true if drain is performed and kernfs_mutex was temporarily - * released. %false if @kn was already drained and no operation was - * necessary. - * - * The caller is responsible for ensuring @kn stays pinned while this - * function is in progress even if it gets removed by someone else. + * Drain existing usages. */ -static bool kernfs_drain(struct kernfs_node *kn) - __releases(&kernfs_mutex) __acquires(&kernfs_mutex) +static void kernfs_drain(struct kernfs_node *kn) { struct kernfs_root *root = kernfs_root(kn); - lockdep_assert_held(&kernfs_mutex); WARN_ON_ONCE(atomic_read(&kn->active) >= 0); - /* - * We want to go through the active ref lockdep annotation at least - * once for all node removals, but the lockdep annotation can't be - * nested inside kernfs_mutex and deactivation can't make forward - * progress if we keep dropping the mutex. Use JUST_ACTIVATED to - * force the slow path once for each deactivation if lockdep is - * enabled. - */ - if ((!kernfs_lockdep(kn) || !(kn->flags & KERNFS_JUST_DEACTIVATED)) && - atomic_read(&kn->active) == KN_DEACTIVATED_BIAS) - return false; - - kn->flags &= ~KERNFS_JUST_DEACTIVATED; - mutex_unlock(&kernfs_mutex); - if (kernfs_lockdep(kn)) { rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) @@ -226,9 +202,6 @@ static bool kernfs_drain(struct kernfs_node *kn) lock_acquired(&kn->dep_map, _RET_IP_); rwsem_release(&kn->dep_map, 1, _RET_IP_); } - - mutex_lock(&kernfs_mutex); - return true; } /** @@ -474,6 +447,49 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn, } /** + * kernfs_remove_one - remove kernfs_node from parent + * @acxt: addrm context to use + * @kn: kernfs_node to be removed + * + * Mark @kn removed and drop nlink of parent inode if @kn is a + * directory. @kn is unlinked from the children list. + * + * This function should be called between calls to + * kernfs_addrm_start() and kernfs_addrm_finish() and should be + * passed the same @acxt as passed to kernfs_addrm_start(). + * + * LOCKING: + * Determined by kernfs_addrm_start(). + */ +static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt, + struct kernfs_node *kn) +{ + struct kernfs_iattrs *ps_iattr; + + /* + * Removal can be called multiple times on the same node. Only the + * first invocation is effective and puts the base ref. + */ + if (atomic_read(&kn->active) < 0) + return; + + if (kn->parent) { + kernfs_unlink_sibling(kn); + + /* Update timestamps on the parent */ + ps_iattr = kn->parent->iattr; + if (ps_iattr) { + ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME; + ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME; + } + } + + atomic_add(KN_DEACTIVATED_BIAS, &kn->active); + kn->u.removed_list = acxt->removed; + acxt->removed = kn; +} + +/** * kernfs_addrm_finish - finish up kernfs_node add/remove * @acxt: addrm context to finish up * @@ -496,6 +512,7 @@ void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt) acxt->removed = kn->u.removed_list; + kernfs_drain(kn); kernfs_unmap_bin_file(kn); kernfs_put(kn); } @@ -805,73 +822,23 @@ static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos, return pos->parent; } -static void __kernfs_deactivate(struct kernfs_node *kn) -{ - struct kernfs_node *pos; - - lockdep_assert_held(&kernfs_mutex); - - /* prevent any new usage under @kn by deactivating all nodes */ - pos = NULL; - while ((pos = kernfs_next_descendant_post(pos, kn))) { - if (atomic_read(&pos->active) >= 0) { - atomic_add(KN_DEACTIVATED_BIAS, &pos->active); - pos->flags |= KERNFS_JUST_DEACTIVATED; - } - } - - /* - * Drain the subtree. If kernfs_drain() blocked to drain, which is - * indicated by %true return, it temporarily released kernfs_mutex - * and the rbtree might have been modified inbetween breaking our - * future walk. Restart the walk after each %true return. - */ - pos = NULL; - while ((pos = kernfs_next_descendant_post(pos, kn))) { - bool drained; - - kernfs_get(pos); - drained = kernfs_drain(pos); - kernfs_put(pos); - if (drained) - pos = NULL; - } -} - static void __kernfs_remove(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn) { - struct kernfs_node *pos; - - lockdep_assert_held(&kernfs_mutex); + struct kernfs_node *pos, *next; if (!kn) return; pr_debug("kernfs %s: removing\n", kn->name); - __kernfs_deactivate(kn); - - /* unlink the subtree node-by-node */ + next = NULL; do { - struct kernfs_iattrs *ps_iattr; - - pos = kernfs_leftmost_descendant(kn); - - if (pos->parent) { - kernfs_unlink_sibling(pos); - - /* update timestamps on the parent */ - ps_iattr = pos->parent->iattr; - if (ps_iattr) { - ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME; - ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME; - } - } - - pos->u.removed_list = acxt->removed; - acxt->removed = pos; - } while (pos != kn); + pos = next; + next = kernfs_next_descendant_post(pos, kn); + if (pos) + kernfs_remove_one(acxt, pos); + } while (next); } /** diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index 61bd7ae..289d4f6 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -37,7 +37,6 @@ enum kernfs_node_type { #define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK enum kernfs_node_flag { - KERNFS_JUST_DEACTIVATED = 0x0010, /* used to aid lockdep annotation */ KERNFS_NS = 0x0020, KERNFS_HAS_SEQ_SHOW = 0x0040, KERNFS_HAS_MMAP = 0x0080, |