diff options
| -rw-r--r-- | fs/smb/server/vfs_cache.c | 102 |
1 files changed, 76 insertions, 26 deletions
diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c index dc4037ef1834..354c4d8a1cfb 100644 --- a/fs/smb/server/vfs_cache.c +++ b/fs/smb/server/vfs_cache.c @@ -418,6 +418,14 @@ static void __ksmbd_remove_durable_fd(struct ksmbd_file *fp) return; idr_remove(global_ft.idr, fp->persistent_id); + /* + * Clear persistent_id so a later __ksmbd_close_fd() that runs from a + * delayed putter (e.g. when a concurrent ksmbd_lookup_fd_inode() + * walker held the final reference) does not re-issue idr_remove() on + * an id that idr_alloc_cyclic() may have already handed out to a new + * durable handle. + */ + fp->persistent_id = KSMBD_NO_FID; } static void ksmbd_remove_durable_fd(struct ksmbd_file *fp) @@ -521,6 +529,20 @@ static struct ksmbd_file *__ksmbd_lookup_fd(struct ksmbd_file_table *ft, static void __put_fd_final(struct ksmbd_work *work, struct ksmbd_file *fp) { + /* + * Detached durable fp -- session_fd_check() cleared fp->conn at + * preserve, so this fp is no longer tracked by any conn's + * stats.open_files_count. This happens when + * ksmbd_scavenger_dispose_dh() hands the final close off to an + * m_fp_list walker (e.g. ksmbd_lookup_fd_inode()) whose work->conn + * is unrelated to the conn that originally opened the handle; close + * via the NULL-ft path so we do not underflow that unrelated + * counter. + */ + if (!fp->conn) { + __ksmbd_close_fd(NULL, fp); + return; + } __ksmbd_close_fd(&work->sess->file_table, fp); atomic_dec(&work->conn->stats.open_files_count); } @@ -1033,24 +1055,37 @@ static bool ksmbd_durable_scavenger_alive(void) return true; } -static void ksmbd_scavenger_dispose_dh(struct list_head *head) +static void ksmbd_scavenger_dispose_dh(struct ksmbd_file *fp) { - while (!list_empty(head)) { - struct ksmbd_file *fp; + /* + * Durable-preserved fp can remain linked on f_ci->m_fp_list for + * share-mode checks. Unlink it before final close; fp->node is not + * available as a scavenger-private list node because re-adding it to + * another list corrupts m_fp_list. + */ + down_write(&fp->f_ci->m_lock); + list_del_init(&fp->node); + up_write(&fp->f_ci->m_lock); - fp = list_first_entry(head, struct ksmbd_file, node); - list_del_init(&fp->node); + /* + * Drop both the durable lifetime reference and the transient reference + * taken by the scavenger under global_ft.lock. If a concurrent + * ksmbd_lookup_fd_inode() (or any other m_fp_list walker) snatched fp + * before the unlink above, that holder owns the final close via + * ksmbd_fd_put() -> __ksmbd_close_fd(). Otherwise the scavenger is + * the last putter and finalises fp here. + */ + if (atomic_sub_and_test(2, &fp->refcount)) __ksmbd_close_fd(NULL, fp); - } } static int ksmbd_durable_scavenger(void *dummy) { struct ksmbd_file *fp = NULL; + struct ksmbd_file *expired_fp; unsigned int id; unsigned int min_timeout = 1; bool found_fp_timeout; - LIST_HEAD(scavenger_list); unsigned long remaining_jiffies; __module_get(THIS_MODULE); @@ -1060,8 +1095,6 @@ static int ksmbd_durable_scavenger(void *dummy) if (try_to_freeze()) continue; - found_fp_timeout = false; - remaining_jiffies = wait_event_timeout(dh_wq, ksmbd_durable_scavenger_alive() == false, __msecs_to_jiffies(min_timeout)); @@ -1070,23 +1103,39 @@ static int ksmbd_durable_scavenger(void *dummy) else min_timeout = DURABLE_HANDLE_MAX_TIMEOUT; - write_lock(&global_ft.lock); - idr_for_each_entry(global_ft.idr, fp, id) { - if (!fp->durable_timeout) - continue; + do { + expired_fp = NULL; + found_fp_timeout = false; - if (atomic_read(&fp->refcount) > 1 || - fp->conn) - continue; - - found_fp_timeout = true; - if (fp->durable_scavenger_timeout <= - jiffies_to_msecs(jiffies)) { - __ksmbd_remove_durable_fd(fp); - list_add(&fp->node, &scavenger_list); - } else { + write_lock(&global_ft.lock); + idr_for_each_entry(global_ft.idr, fp, id) { unsigned long durable_timeout; + if (!fp->durable_timeout) + continue; + + if (atomic_read(&fp->refcount) > 1 || + fp->conn) + continue; + + found_fp_timeout = true; + if (fp->durable_scavenger_timeout <= + jiffies_to_msecs(jiffies)) { + __ksmbd_remove_durable_fd(fp); + /* + * Take a transient reference so fp + * cannot be freed by an in-flight + * ksmbd_lookup_fd_inode() that found + * it through f_ci->m_fp_list while we + * drop global_ft.lock and reach the + * m_fp_list unlink in + * ksmbd_scavenger_dispose_dh(). + */ + atomic_inc(&fp->refcount); + expired_fp = fp; + break; + } + durable_timeout = fp->durable_scavenger_timeout - jiffies_to_msecs(jiffies); @@ -1094,10 +1143,11 @@ static int ksmbd_durable_scavenger(void *dummy) if (min_timeout > durable_timeout) min_timeout = durable_timeout; } - } - write_unlock(&global_ft.lock); + write_unlock(&global_ft.lock); - ksmbd_scavenger_dispose_dh(&scavenger_list); + if (expired_fp) + ksmbd_scavenger_dispose_dh(expired_fp); + } while (expired_fp); if (found_fp_timeout == false) break; |