From nobody Thu Nov 28 09:41:53 2024 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 7479021BAF3; Wed, 2 Oct 2024 21:27:42 +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=1727904462; cv=none; b=RkDTLhOzLpuW54XA65creR0JbPvhDqCHl2+kqx13rPH3T6Rm3CJoBffczTcIdF3rYOp90vE63KeWcuGD2Q/vEnpf5frhZlJPPSrO8gQob1OAhFPwKDad95FLXqEjhdpMxznlaZAuF8yr/S8QOTfMyisyWq5jVc621CRyE0o4wUw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727904462; c=relaxed/simple; bh=nWAObiv1pT63De3yrHB7U+GTf1hLNrlZ3AMOKfvjPAI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Lp5yYXgHHkhK5ILmfCNNa3Om8EN/eejmT+YT5eoTZpqsxoNQ+EWtfnK6eAwu4lrIcTNSjDnVNhohVcqvBFYxcS0quKJS2cHDyiDqBRIzx8CSgf1QoK4rGskJpmBX1dGMoXqZF1U6EdKDiOrhVaVktTRYKSJL5sXjQ83RIuy52gs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rrg8jFdo; 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="rrg8jFdo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CEAC9C4CED0; Wed, 2 Oct 2024 21:27:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727904462; bh=nWAObiv1pT63De3yrHB7U+GTf1hLNrlZ3AMOKfvjPAI=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=rrg8jFdosDYWMwAA92V2hbU+Yuic3cTXnqQJL7/CjaS4rr5GNRsDVyFogFc7wde8b 3+ytxmfZcVBW7BHEAGL4MUuw8r8fjtd6551m/mw3PBYEMfUcJX5EVnFh9Dl4h9g9bq E+0f3RyVBQuyVN+jR02fOAGU05QU3hphedY25tfubjbgoT7Ovjfw1tUksa+EGwTKEP cQw9zf61IzShMjY9Nc7Pn7ReERF7yn1KIs8f8bQPZs7a9O4goDuhvZZeDLeqBbBWs0 G1gFKZ/7FA/CHJ+OL4QeRprqQq6UL2esAzsdREnCvyhDIodZoeCmPj/niFarTH0M/n olAqzjyT6/E3Q== From: Jeff Layton Date: Wed, 02 Oct 2024 17:27:19 -0400 Subject: [PATCH v10 04/12] fs: have setattr_copy handle multigrain timestamps appropriately Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241002-mgtime-v10-4-d1c4717f5284@kernel.org> References: <20241002-mgtime-v10-0-d1c4717f5284@kernel.org> In-Reply-To: <20241002-mgtime-v10-0-d1c4717f5284@kernel.org> To: John Stultz , Thomas Gleixner , Stephen Boyd , Alexander Viro , Christian Brauner , Jan Kara , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Randy Dunlap , Chandan Babu R , "Darrick J. Wong" , Theodore Ts'o , Andreas Dilger , Chris Mason , Josef Bacik , David Sterba , Hugh Dickins , Andrew Morton , Chuck Lever , Vadim Fedorenko Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org, Jeff Layton X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3623; i=jlayton@kernel.org; h=from:subject:message-id; bh=nWAObiv1pT63De3yrHB7U+GTf1hLNrlZ3AMOKfvjPAI=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBm/bq/ifAGWvuvl6BRwMs4Uby9r2RObyp81rJWQ t0O66nsopCJAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCZv26vwAKCRAADmhBGVaC FUFdEACg0WGt0WZDsR4lYHjv29oOUq3iMhe6DMxJ/AIvWuxlPjl9W5bf1/v4xbhac64hqIi9t75 Ed8baE1O4menek+QPLY2fRZnnBQGeQXQg9S9rBIhp0xF3IDD+27FJYF8TT5BItAgxM+tE08Jj79 TxEMXfS4ytrx3H/6P8gkkrxj/Vq2KgyY+pXxhr6SJL09O3NDWwkl+CmZlhsbJqaDtd0Bu2Nkqoc 7XU2I/HmGc9+oXYAi4FK+WjMwm+NdZxBDxUf+mxJELst25MI6Gn7ZqLMfihTZDlg/lkXmnjoMYc CpIIZoyJ+HTB+U9Kge0Knzi+yySpldS6Jv2RXPCtm4ptKKFDi2JO1mhHQyQ6U0oVux1XaGQMEda hhXz0O+U2tobDuICI10a29pVUBbbzgFMTN60MymsFmu7SunVDjCCb1GVEoIOOfAITwjZdcdxth/ d8tPUuSxoGy4Xm9bPfSc6kUuaWp/GqTpsjbtT22UjDOKz1DJfLRmBLrSNeW2c+1WW6yPWoA5wCX gAjJGRkY+f5UkqUIhYc/guqwfh2fkG5UVSrwX7YjFkNlNJjQxYPkFfaC5YpfqjGNJjS8Mm/XNw8 RuKnlGcHgkVhCZdFDdF9m9DCLNYtwbNGQmPRyak0iaHm3uyL+MOfkADpMxPn3YOLLNHu/1Gw7j9 rHKf7yUI65eskTQ== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 The setattr codepath is still using coarse-grained timestamps, even on multigrain filesystems. To fix this, fetch the timestamp for ctime updates later, at the point where the assignment occurs in setattr_copy. On a multigrain inode, ignore the ia_ctime in the attrs, and always update the ctime to the current clock value. Update the atime and mtime with the same value (if needed) unless they are being set to other specific values, a'la utimes(). Do not do this universally however, as some filesystems (e.g. most networked fs) want to do an explicit update elsewhere before updating the local inode. Reviewed-by: Darrick J. Wong Reviewed-by: Josef Bacik Reviewed-by: Jan Kara Tested-by: Randy Dunlap # documentation bits Signed-off-by: Jeff Layton --- fs/attr.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 46 insertions(+), 6 deletions(-) diff --git a/fs/attr.c b/fs/attr.c index c04d19b58f1224c2149da57e3224b7bbbc83561f..0309c2bd8afa04bc43db6ff207f= 8a58d9f6a617d 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -271,6 +271,42 @@ int inode_newsize_ok(const struct inode *inode, loff_t= offset) } EXPORT_SYMBOL(inode_newsize_ok); =20 +/** + * setattr_copy_mgtime - update timestamps for mgtime inodes + * @inode: inode timestamps to be updated + * @attr: attrs for the update + * + * With multigrain timestamps, take more care to prevent races when + * updating the ctime. Always update the ctime to the very latest using + * the standard mechanism, and use that to populate the atime and mtime + * appropriately (unless those are being set to specific values). + */ +static void setattr_copy_mgtime(struct inode *inode, const struct iattr *a= ttr) +{ + unsigned int ia_valid =3D 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; + } + + now =3D 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) + inode_set_atime_to_ts(inode, now); + + if (ia_valid & ATTR_MTIME_SET) + inode_set_mtime_to_ts(inode, attr->ia_mtime); + else if (ia_valid & ATTR_MTIME) + inode_set_mtime_to_ts(inode, now); +} + /** * setattr_copy - copy simple metadata updates into the generic inode * @idmap: idmap of the mount the inode was found from @@ -303,12 +339,6 @@ void setattr_copy(struct mnt_idmap *idmap, struct inod= e *inode, =20 i_uid_update(idmap, attr, inode); i_gid_update(idmap, attr, inode); - if (ia_valid & ATTR_ATIME) - 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_MODE) { umode_t mode =3D attr->ia_mode; if (!in_group_or_capable(idmap, inode, @@ -316,6 +346,16 @@ void setattr_copy(struct mnt_idmap *idmap, struct inod= e *inode, mode &=3D ~S_ISGID; inode->i_mode =3D mode; } + + if (is_mgtime(inode)) + return setattr_copy_mgtime(inode, attr); + + if (ia_valid & ATTR_ATIME) + 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); } EXPORT_SYMBOL(setattr_copy); =20 --=20 2.46.2