From patchwork Wed Jul 19 22:19:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 13319556 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 014B7C001DE for ; Wed, 19 Jul 2023 22:19:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229884AbjGSWTg (ORCPT ); Wed, 19 Jul 2023 18:19:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229663AbjGSWTf (ORCPT ); Wed, 19 Jul 2023 18:19:35 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 55E481FE8; Wed, 19 Jul 2023 15:19:32 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 0D92B222D9; Wed, 19 Jul 2023 22:19:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1689805171; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BqbNsJJZFHzrk+OQKgoo/9ZCZoHSnGZs9WOrN7/OQBs=; b=ADRsD1Jcw/vcGrx4BTVWmM2VK7daFp0uxIOqfl9S+jTVz2ItB7vFeY6PJ3wiQ5BpjDiyv1 Ks8EVusKip5WUHqhQd5lp0euD0ApelIq/ha14TXlRobJWwIqPUAc9PcjuN+iG3TBzJ7tLE bX/vpj0NVBckk1Wqtrr3LcPOQC7S8a8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1689805171; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BqbNsJJZFHzrk+OQKgoo/9ZCZoHSnGZs9WOrN7/OQBs=; b=MTk8FDvkwaRjQnMM4zvFMuqLq9yAKkyyuSUoPvbHoEQwl3inTM9iY25+Iyvi7Xnt/CX1M/ S6X5zmrqZleoNNBw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id CB6CD1361C; Wed, 19 Jul 2023 22:19:30 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 4rUtLHJhuGQLJgAAMHmgww (envelope-from ); Wed, 19 Jul 2023 22:19:30 +0000 From: Gabriel Krisman Bertazi To: viro@zeniv.linux.org.uk, brauner@kernel.org, tytso@mit.edu, ebiggers@kernel.org, jaegeuk@kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Gabriel Krisman Bertazi , Gabriel Krisman Bertazi Subject: [PATCH v3 1/7] fs: Expose name under lookup to d_revalidate hook Date: Wed, 19 Jul 2023 18:19:12 -0400 Message-ID: <20230719221918.8937-2-krisman@suse.de> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230719221918.8937-1-krisman@suse.de> References: <20230719221918.8937-1-krisman@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Gabriel Krisman Bertazi Negative dentries support on case-insensitive ext4/f2fs will require access to the name under lookup to ensure it matches the dentry. This adds an optional new flavor of cached dentry revalidation hook to expose this extra parameter. I'm fine with extending d_revalidate instead of adding a new hook, if it is considered cleaner and the approach is accepted. I wrote a new hook to simplify reviewing. Reviewed-by: Theodore Ts'o Signed-off-by: Gabriel Krisman Bertazi --- Changes since v2: - Document d_revalidate_name hook. (Eric) --- Documentation/filesystems/locking.rst | 3 +++ Documentation/filesystems/vfs.rst | 12 ++++++++++++ fs/dcache.c | 2 +- fs/namei.c | 23 ++++++++++++++--------- include/linux/dcache.h | 1 + 5 files changed, 31 insertions(+), 10 deletions(-) diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index ed148919e11a..d68997ba6584 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -18,6 +18,8 @@ dentry_operations prototypes:: int (*d_revalidate)(struct dentry *, unsigned int); + int (*d_revalidate_name)(struct dentry *, const struct qstr *, + unsigned int); int (*d_weak_revalidate)(struct dentry *, unsigned int); int (*d_hash)(const struct dentry *, struct qstr *); int (*d_compare)(const struct dentry *, @@ -37,6 +39,7 @@ locking rules: ops rename_lock ->d_lock may block rcu-walk ================== =========== ======== ============== ======== d_revalidate: no no yes (ref-walk) maybe +d_revalidate_name: no no yes (ref-walk) maybe d_weak_revalidate: no no yes no d_hash no no no maybe d_compare: yes no no maybe diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index cb2a97e49872..34c842bd7cb2 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -1252,6 +1252,8 @@ defined: struct dentry_operations { int (*d_revalidate)(struct dentry *, unsigned int); + int (*d_revalidate_name)(struct dentry *, const struct qstr *, + unsigned int); int (*d_weak_revalidate)(struct dentry *, unsigned int); int (*d_hash)(const struct dentry *, struct qstr *); int (*d_compare)(const struct dentry *, @@ -1288,6 +1290,16 @@ defined: return -ECHILD and it will be called again in ref-walk mode. +``d_revalidate_name`` + Variant of d_revalidate that also provides the name under look-up. Most + filesystems will keep it as NULL, unless there are particular semantics + for filenames encoding that need to be handled during dentry + revalidation. + + When available, it is called in lieu of d_revalidate and has the same + locking rules and return semantics. Refer to d_revalidate for more + information. + ``d_weak_revalidate`` called when the VFS needs to revalidate a "jumped" dentry. This is called when a path-walk ends at dentry that was not acquired diff --git a/fs/dcache.c b/fs/dcache.c index 52e6d5fdab6b..98521862e58a 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1928,7 +1928,7 @@ void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) dentry->d_flags |= DCACHE_OP_HASH; if (op->d_compare) dentry->d_flags |= DCACHE_OP_COMPARE; - if (op->d_revalidate) + if (op->d_revalidate || op->d_revalidate_name) dentry->d_flags |= DCACHE_OP_REVALIDATE; if (op->d_weak_revalidate) dentry->d_flags |= DCACHE_OP_WEAK_REVALIDATE; diff --git a/fs/namei.c b/fs/namei.c index e56ff39a79bc..84df0ddd20db 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -853,11 +853,16 @@ static bool try_to_unlazy_next(struct nameidata *nd, struct dentry *dentry) return false; } -static inline int d_revalidate(struct dentry *dentry, unsigned int flags) +static inline int d_revalidate(struct dentry *dentry, + const struct qstr *name, + unsigned int flags) { - if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) + + if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) { + if (dentry->d_op->d_revalidate_name) + return dentry->d_op->d_revalidate_name(dentry, name, flags); return dentry->d_op->d_revalidate(dentry, flags); - else + } else return 1; } @@ -1565,7 +1570,7 @@ static struct dentry *lookup_dcache(const struct qstr *name, { struct dentry *dentry = d_lookup(dir, name); if (dentry) { - int error = d_revalidate(dentry, flags); + int error = d_revalidate(dentry, name, flags); if (unlikely(error <= 0)) { if (!error) d_invalidate(dentry); @@ -1636,19 +1641,19 @@ static struct dentry *lookup_fast(struct nameidata *nd) if (read_seqcount_retry(&parent->d_seq, nd->seq)) return ERR_PTR(-ECHILD); - status = d_revalidate(dentry, nd->flags); + status = d_revalidate(dentry, &nd->last, nd->flags); if (likely(status > 0)) return dentry; if (!try_to_unlazy_next(nd, dentry)) return ERR_PTR(-ECHILD); if (status == -ECHILD) /* we'd been told to redo it in non-rcu mode */ - status = d_revalidate(dentry, nd->flags); + status = d_revalidate(dentry, &nd->last, nd->flags); } else { dentry = __d_lookup(parent, &nd->last); if (unlikely(!dentry)) return NULL; - status = d_revalidate(dentry, nd->flags); + status = d_revalidate(dentry, &nd->last, nd->flags); } if (unlikely(status <= 0)) { if (!status) @@ -1676,7 +1681,7 @@ static struct dentry *__lookup_slow(const struct qstr *name, if (IS_ERR(dentry)) return dentry; if (unlikely(!d_in_lookup(dentry))) { - int error = d_revalidate(dentry, flags); + int error = d_revalidate(dentry, name, flags); if (unlikely(error <= 0)) { if (!error) { d_invalidate(dentry); @@ -3421,7 +3426,7 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file, if (d_in_lookup(dentry)) break; - error = d_revalidate(dentry, nd->flags); + error = d_revalidate(dentry, &nd->last, nd->flags); if (likely(error > 0)) break; if (error) diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 6b351e009f59..b6188f2e8950 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -127,6 +127,7 @@ enum dentry_d_lock_class struct dentry_operations { int (*d_revalidate)(struct dentry *, unsigned int); + int (*d_revalidate_name)(struct dentry *, const struct qstr *, unsigned int); int (*d_weak_revalidate)(struct dentry *, unsigned int); int (*d_hash)(const struct dentry *, struct qstr *); int (*d_compare)(const struct dentry *,