From patchwork Wed Aug 4 16:06:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 12419371 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B60AC43216 for ; Wed, 4 Aug 2021 16:07:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E51060F35 for ; Wed, 4 Aug 2021 16:07:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233325AbhHDQH7 (ORCPT ); Wed, 4 Aug 2021 12:07:59 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:42100 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233273AbhHDQH4 (ORCPT ); Wed, 4 Aug 2021 12:07:56 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id 4B2351F4080F From: Gabriel Krisman Bertazi To: jack@suse.com, amir73il@gmail.com Cc: djwong@kernel.org, tytso@mit.edu, david@fromorbit.com, dhowells@redhat.com, khazhy@google.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-api@vger.kernel.org, Gabriel Krisman Bertazi , kernel@collabora.com Subject: [PATCH v5 17/23] fanotify: Preallocate per superblock mark error event Date: Wed, 4 Aug 2021 12:06:06 -0400 Message-Id: <20210804160612.3575505-18-krisman@collabora.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210804160612.3575505-1-krisman@collabora.com> References: <20210804160612.3575505-1-krisman@collabora.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Error reporting needs to be done in an atomic context. This patch introduces a single error slot for superblock marks that report the FAN_FS_ERROR event, to be used during event submission. Signed-off-by: Gabriel Krisman Bertazi --- fs/notify/fanotify/fanotify.c | 22 +++++++++++++++++ fs/notify/fanotify/fanotify.h | 13 ++++++++++ fs/notify/fanotify/fanotify_user.c | 39 +++++++++++++++++++++++++++++- 3 files changed, 73 insertions(+), 1 deletion(-) diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index ca74199f11e2..0678d35432a7 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -828,6 +828,24 @@ static void fanotify_free_name_event(struct fanotify_event *event) kfree(FANOTIFY_NE(event)); } +static void fanotify_free_error_event(struct fanotify_event *event) +{ + struct fanotify_error_event *fee; + + if (!event) + return; + + fee = FANOTIFY_EE(event); + /* + * If this is an active error event, disassociate it from the + * mark prior to removal. + */ + if (fee->sb_mark->fee_slot == fee) + fee->sb_mark->fee_slot = NULL; + + kfree(fee); +} + static void fanotify_free_event(struct fsnotify_event *fsn_event) { struct fanotify_event *event; @@ -850,6 +868,9 @@ static void fanotify_free_event(struct fsnotify_event *fsn_event) case FANOTIFY_EVENT_TYPE_OVERFLOW: kfree(event); break; + case FANOTIFY_EVENT_TYPE_FS_ERROR: + fanotify_free_error_event(event); + break; default: WARN_ON_ONCE(1); } @@ -867,6 +888,7 @@ static void fanotify_free_mark(struct fsnotify_mark *mark) if (mark->flags & FANOTIFY_MARK_FLAG_SB_MARK) { struct fanotify_sb_mark *fa_mark = FANOTIFY_SB_MARK(mark); + fanotify_free_error_event(&fa_mark->fee_slot->fae); kmem_cache_free(fanotify_sb_mark_cache, fa_mark); } else { kmem_cache_free(fanotify_mark_cache, mark); diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h index aa555975c0f8..206dc6cfd671 100644 --- a/fs/notify/fanotify/fanotify.h +++ b/fs/notify/fanotify/fanotify.h @@ -142,6 +142,7 @@ FANOTIFY_MARK_FLAG(SB_MARK); struct fanotify_sb_mark { struct fsnotify_mark fsn_mark; + struct fanotify_error_event *fee_slot; }; static inline @@ -164,6 +165,7 @@ enum fanotify_event_type { FANOTIFY_EVENT_TYPE_PATH, FANOTIFY_EVENT_TYPE_PATH_PERM, FANOTIFY_EVENT_TYPE_OVERFLOW, /* struct fanotify_event */ + FANOTIFY_EVENT_TYPE_FS_ERROR, /* struct fanotify_error_event */ __FANOTIFY_EVENT_TYPE_NUM }; @@ -219,6 +221,17 @@ FANOTIFY_NE(struct fanotify_event *event) return container_of(event, struct fanotify_name_event, fae); } +struct fanotify_error_event { + struct fanotify_event fae; + struct fanotify_sb_mark *sb_mark; /* Back reference to the mark. */ +}; + +static inline struct fanotify_error_event * +FANOTIFY_EE(struct fanotify_event *event) +{ + return container_of(event, struct fanotify_error_event, fae); +} + static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event) { if (event->type == FANOTIFY_EVENT_TYPE_FID) diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 6dad2a00e337..76c1c805af3d 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -167,6 +167,22 @@ static void fanotify_unhash_event(struct fsnotify_group *group, hlist_del_init(&event->merge_list); } +static struct fanotify_error_event *fanotify_alloc_error_event( + struct fanotify_sb_mark *sb_mark) + +{ + struct fanotify_error_event *fee; + + fee = kzalloc(sizeof(*fee), GFP_KERNEL_ACCOUNT); + if (!fee) + return NULL; + + fanotify_init_event(&fee->fae, 0, FS_ERROR); + fee->sb_mark = sb_mark; + + return fee; +} + /* * Get an fanotify notification event if one exists and is small * enough to fit in "count". Return an error pointer if the count @@ -994,6 +1010,7 @@ static int fanotify_add_mark(struct fsnotify_group *group, { struct fsnotify_mark *fsn_mark; __u32 added; + int ret = 0; mutex_lock(&group->mark_mutex); fsn_mark = fsnotify_find_mark(connp, group); @@ -1004,13 +1021,33 @@ static int fanotify_add_mark(struct fsnotify_group *group, return PTR_ERR(fsn_mark); } } + + /* + * Error events are allocated per super-block mark only if + * strictly needed (i.e. FAN_FS_ERROR was requested). + */ + if (type == FSNOTIFY_OBJ_TYPE_SB && !(flags & FAN_MARK_IGNORED_MASK) && + (mask & FAN_FS_ERROR)) { + struct fanotify_sb_mark *sb_mark = FANOTIFY_SB_MARK(fsn_mark); + + if (!sb_mark->fee_slot) { + sb_mark->fee_slot = fanotify_alloc_error_event(sb_mark); + if (!sb_mark->fee_slot) { + ret = -ENOMEM; + goto out; + } + } + } + added = fanotify_mark_add_to_mask(fsn_mark, mask, flags); if (added & ~fsnotify_conn_mask(fsn_mark->connector)) fsnotify_recalc_mask(fsn_mark->connector); + +out: mutex_unlock(&group->mark_mutex); fsnotify_put_mark(fsn_mark); - return 0; + return ret; } static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,