From patchwork Thu Sep 5 12:41:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 13792297 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 477171A071A; Thu, 5 Sep 2024 12:42:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725540133; cv=none; b=ehQXQ6VuQJ3Vg65v76gpGazQEptX6/HAPzR3GtQ8192qcrJDtSNMJI0azOvUVdXn13uKXpO0NksIvpPBeIejnLqwKjPmMUeORLyHZIrI3ymgqNulgiRzu15CbAXjpT9ZcRKUPSUO7KAz0g/SRwh6i1d+UUwMdK2d9xqV34TlC+4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725540133; c=relaxed/simple; bh=LiV0clf9L6NQX5LxYkFyOmngi4CQOovdgBWSLgxIFp8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=qXeboa+1lC0oylwTKnSnIgCyMevuZpRVDzDUkDQbHs+CUV5giNh8QUWG0MEj5atETpW5ymXxiNcWnzi4mGncS7mVkMQzhgcQ2R4TKjyeTQZuM9TU9W5q/FrDXLI9I54iuZgv6a4bbZgKTOmXZwFEcx438K9rdZt8yj+7GrIzL2I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UPjMfY4g; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UPjMfY4g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9012CC4CECA; Thu, 5 Sep 2024 12:42:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725540132; bh=LiV0clf9L6NQX5LxYkFyOmngi4CQOovdgBWSLgxIFp8=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=UPjMfY4gBQ/Lin4WBYi6iW0UAHBMLJR8ncqfrru1kIVeUrRrUc5W/YmR5He6AJlkO mWvSs/3eqCj35ZGATV2+ZbGPRWQ5kmz7cMtSu9JXi05iVr0VImA4csIPE+uw4r3mj/ C94K3P9zTOjATkx1FraBiQVqqK1/eiAkK2GyLmRNW+zsMqR9kSrR7992j30EtxLAfI 0s8evmCwq7tykl3DFnuVJtzglv1OaAwxc8TF8fES57agPlnrzHUIrSqCGbGMCTIIdq uqkOKbaCrrAjTU0kS2S+Hge4ROvRtkv4dr5y+4Iaixld/z41Bsv0XF9lPXwsnzaaRl awe1Rusp+Y9ZA== From: Jeff Layton Date: Thu, 05 Sep 2024 08:41:53 -0400 Subject: [PATCH v4 09/11] fs: handle delegated timestamps in setattr_copy_mgtime Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240905-delstid-v4-9-d3e5fd34d107@kernel.org> References: <20240905-delstid-v4-0-d3e5fd34d107@kernel.org> In-Reply-To: <20240905-delstid-v4-0-d3e5fd34d107@kernel.org> To: Chuck Lever , Neil Brown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Trond Myklebust , Anna Schumaker , Alexander Viro , Christian Brauner , Jan Kara Cc: Tom Haynes , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jeff Layton X-Mailer: b4 0.14.1 X-Developer-Signature: v=1; a=openpgp-sha256; l=6296; i=jlayton@kernel.org; h=from:subject:message-id; bh=LiV0clf9L6NQX5LxYkFyOmngi4CQOovdgBWSLgxIFp8=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBm2acVxmRxlKc2nczzBdKjuAeqrBthaSyeahB9x 280UJXE10uJAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCZtmnFQAKCRAADmhBGVaC FX/gD/4rFScHDd8r5gSdDDT0ZDTLV05DTPvMrlTsWFJuiY13NJi7q7W3bRue8E/842HppVyuihQ 9/rCf/vakl1qhiK4CjkE1DDwaUJP/vHUbU6lLe7MHSKqrTrZuiicTZqAMfw/ciex8tBBTDIy6hs h56ryuSIoAkqz9z1CUxh4qloQX6NZ/qPDLEoafQ/0d/hDhyQGyfxuJr2NF+dvbLQg04fyWAbayp h798dWgfzuCOeYSNtYQfdQQbLZUR0drBQi8gPz6s+jscaMXZ/4FS0ZJhpWpnTQNIugIMrfvSCD6 reNRBRrDuJg5y61PJn3E0GSioVik+99YIy3AFobq/CP8nvAX7qwt2VyX+26qytIZpg1Z15wFFlO BVBEbQfJUaV9/7ksV8Mm7EY6AEqfomqcEMEHI7BEnxoKTwbdK28i6x8E9s/CS2ynJ10kKwaMd3g +MlXfOfp3kuxwmeS6u8T5Eyr/tM+o4HFdiKhqZD5OiRAFq+xAi4csuf2oPdrC5/sNLCgsM/eozZ hUxWpZX2MiIewYoNgvsbi/RhqEBGYrJjAO638SFKG068dANiVmlqnVU5as2lJoI/O7yFyB2YxWz igs9kkMmqnNuaGv0aBT/4lUyM1BQg1uzruGUkJuluudhheq5zjW4LZZrhuCzTBJK2qthIkVq5Ds vbDmgCPYVmy4MAQ== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 When updating the ctime on an inode for a SETATTR with a multigrain filesystem, we usually want to take the latest time we can get for the ctime. The exception to this rule is when there is a nfsd write delegation and the server is proxying timestamps from the client. When nfsd gets a CB_GETATTR response, we want to update the timestamp value in the inode to the values that the client is tracking. The client doesn't send a ctime value (since that's always determined by the exported filesystem), but it can send a mtime value. In the case where it does, then we may need to update the ctime to a value commensurate with that instead of the current time. If ATTR_DELEG is set, then use ia_ctime value instead of setting the timestamp to the current time. With the addition of delegated timestamps we can also receive a request to update only the atime, but we may not need to set the ctime. Trust the ATTR_CTIME flag in the update and only update the ctime when it's set. Signed-off-by: Jeff Layton --- fs/attr.c | 28 +++++++++++++-------- fs/inode.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 2 ++ 3 files changed, 94 insertions(+), 10 deletions(-) diff --git a/fs/attr.c b/fs/attr.c index 3bcbc45708a3..392eb62aa609 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -286,16 +286,20 @@ static void setattr_copy_mgtime(struct inode *inode, const struct iattr *attr) unsigned int ia_valid = attr->ia_valid; struct timespec64 now; - /* - * If the ctime isn't being updated then nothing else should be - * either. - */ - if (!(ia_valid & ATTR_CTIME)) { - WARN_ON_ONCE(ia_valid & (ATTR_ATIME|ATTR_MTIME)); - return; + if (ia_valid & ATTR_CTIME) { + /* + * In the case of an update for a write delegation, we must respect + * the value in ia_ctime and not use the current time. + */ + if (ia_valid & ATTR_DELEG) + now = inode_set_ctime_deleg(inode, attr->ia_ctime); + else + now = inode_set_ctime_current(inode); + } else { + /* If ATTR_CTIME isn't set, then ATTR_MTIME shouldn't be either. */ + WARN_ON_ONCE(ia_valid & ATTR_MTIME); } - now = inode_set_ctime_current(inode); if (ia_valid & ATTR_ATIME_SET) inode_set_atime_to_ts(inode, attr->ia_atime); else if (ia_valid & ATTR_ATIME) @@ -354,8 +358,12 @@ void setattr_copy(struct mnt_idmap *idmap, struct inode *inode, inode_set_atime_to_ts(inode, attr->ia_atime); if (ia_valid & ATTR_MTIME) inode_set_mtime_to_ts(inode, attr->ia_mtime); - if (ia_valid & ATTR_CTIME) - inode_set_ctime_to_ts(inode, attr->ia_ctime); + if (ia_valid & ATTR_CTIME) { + if (ia_valid & ATTR_DELEG) + inode_set_ctime_deleg(inode, attr->ia_ctime); + else + inode_set_ctime_to_ts(inode, attr->ia_ctime); + } } EXPORT_SYMBOL(setattr_copy); diff --git a/fs/inode.c b/fs/inode.c index 01f7df1973bd..f0fbfd470d8e 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -2835,6 +2835,80 @@ struct timespec64 inode_set_ctime_current(struct inode *inode) } EXPORT_SYMBOL(inode_set_ctime_current); +/** + * inode_set_ctime_deleg - try to update the ctime on a delegated inode + * @inode: inode to update + * @update: timespec64 to set the ctime + * + * Attempt to atomically update the ctime on behalf of a delegation holder. + * + * The nfs server can call back the holder of a delegation to get updated + * inode attributes, including the mtime. When updating the mtime we may + * need to update the ctime to a value at least equal to that. + * + * This can race with concurrent updates to the inode, in which + * case we just don't do the update. + * + * Note that this works even when multigrain timestamps are not enabled, + * so use it in either case. + */ +struct timespec64 inode_set_ctime_deleg(struct inode *inode, struct timespec64 update) +{ + ktime_t now, floor = atomic64_read(&ctime_floor); + struct timespec64 now_ts, cur_ts; + u32 cur, old; + + /* pairs with try_cmpxchg below */ + cur = smp_load_acquire(&inode->i_ctime_nsec); + cur_ts.tv_nsec = cur & ~I_CTIME_QUERIED; + cur_ts.tv_sec = inode->i_ctime_sec; + + /* If the update is older than the existing value, skip it. */ + if (timespec64_compare(&update, &cur_ts) <= 0) + return cur_ts; + + now = coarse_ctime(floor); + now_ts = ktime_to_timespec64(now); + + /* Clamp the update to "now" if it's in the future */ + if (timespec64_compare(&update, &now_ts) > 0) + update = now_ts; + + update = timestamp_truncate(update, inode); + + /* No need to update if the values are already the same */ + if (timespec64_equal(&update, &cur_ts)) + return cur_ts; + + /* + * Try to swap the nsec value into place. If it fails, that means + * we raced with an update due to a write or similar activity. That + * stamp takes precedence, so just skip the update. + */ +retry: + old = cur; + if (try_cmpxchg(&inode->i_ctime_nsec, &cur, update.tv_nsec)) { + inode->i_ctime_sec = update.tv_sec; + mgtime_counter_inc(mg_ctime_swaps); + return update; + } + + /* + * Was the change due to someone marking the old ctime QUERIED? + * If so then retry the swap. This can only happen once since + * the only way to clear I_CTIME_QUERIED is to stamp the inode + * with a new ctime. + */ + if (!(old & I_CTIME_QUERIED) && (cur == (old | I_CTIME_QUERIED))) + goto retry; + + /* Otherwise, it was a new timestamp. */ + cur_ts.tv_sec = inode->i_ctime_sec; + cur_ts.tv_nsec = cur & ~I_CTIME_QUERIED; + return cur_ts; +} +EXPORT_SYMBOL(inode_set_ctime_deleg); + /** * in_group_or_capable - check whether caller is CAP_FSETID privileged * @idmap: idmap of the mount @inode was found from diff --git a/include/linux/fs.h b/include/linux/fs.h index eff688e75f2f..ea7ed437d2b1 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1544,6 +1544,8 @@ static inline bool fsuidgid_has_mapping(struct super_block *sb, struct timespec64 current_time(struct inode *inode); struct timespec64 inode_set_ctime_current(struct inode *inode); +struct timespec64 inode_set_ctime_deleg(struct inode *inode, + struct timespec64 update); static inline time64_t inode_get_atime_sec(const struct inode *inode) {