From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 4149F2D592D; Wed, 17 Dec 2025 06:11:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765951895; cv=none; b=ivjdsXe+/JfYb/o4QKytl8TjLUtV/TAsoR9Yv2Q7o5rbSNzcjL2rIImOx3yQRc2g4nVX2rkfGfRhtyYOIG0CD7CnoW6ufqUikmHlBaJCaDYNxjWm1nu1FqdfZX/Qk8g4pnnv1Gs56VF0bs/oMLY6zu3DMchAOpNO2iBIvlnXof4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765951895; c=relaxed/simple; bh=7z2I7x3A3H1NrmZ1qwLIAupXj2GXPk76uLOXnCiOh7s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TVlaX/MGN7CauKT3+x9LAsi8FrcFSQZr6kKoyQ1lEzh7j+wJaHqlheNI5voW+Sua77HzT6qQSauGKZEcTCN1RVv/G4QB9J5nXudhTa2Gpg6P0TJ9OgEAg4yiXgGY4B6Y6xdV9vBZPPEdVYy4OnFm5d75vIEt5ZsocFwUTMSlkR8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=lst.de; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=Ya/BLi9T; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Ya/BLi9T" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=cmRL1L+E+zHvjbrc9UAFAA7Vx/VoU2I7wtmuzyJddKQ=; b=Ya/BLi9TcBVCvQJPTSrjTsU+kk cDD4h0wlYMKrmlup9RFOvtaf9JB0JqbIv/VgzIK5pWnxixZzImtM3xyfM0ITzmJxxiaB3HPLuH9bl hqYB74CAIIQDjorsvygDP1Sm8b/LTbDgwofUiPkdBHjUYW6NQZ7BDfMVWWdVNUSFGc900sJr32jDn mdLmc2XzF8Aqj0T9BAiXjowBRIvimBkQigASwH5eK/2TS5XI30LpQLKyUnmzD80w+WV8lA/SKbeaY VJ+xAconzOU+Oft9xbp+qjprWqEda1d1ze2uWah9NloEWPT66JKOEEQJ2kJ0nbZcW+6h41ikM2mhc 9grPGoUQ==; Received: from 2a02-8389-2341-5b80-d601-7564-c2e0-491c.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:d601:7564:c2e0:491c] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vVkl0-00000006DwG-1Iyh; Wed, 17 Dec 2025 06:11:30 +0000 From: Christoph Hellwig To: Christian Brauner Cc: Al Viro , David Sterba , Jan Kara , Mike Marshall , Martin Brandenburg , Carlos Maiolino , Stefan Roesch , Jeff Layton , linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, gfs2@lists.linux.dev, io-uring@vger.kernel.org, devel@lists.orangefs.org, linux-unionfs@vger.kernel.org, linux-mtd@lists.infradead.org, linux-xfs@vger.kernel.org, linux-nfs@vger.kernel.org Subject: [PATCH 08/10] fs: add support for non-blocking timestamp updates Date: Wed, 17 Dec 2025 07:09:41 +0100 Message-ID: <20251217061015.923954-9-hch@lst.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251217061015.923954-1-hch@lst.de> References: <20251217061015.923954-1-hch@lst.de> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Currently file_update_time_flags unconditionally returns -EAGAIN if any timestamp needs to be updated and IOCB_NOWAIT is passed. This makes non-blocking direct writes impossible on file systems with granular enough timestamps. Add a S_NOWAIT to ask for timestamps to not block, and return -EAGAIN in all methods for now. Signed-off-by: Christoph Hellwig Reviewed-by: Jeff Layton --- fs/btrfs/inode.c | 3 +++ fs/fat/misc.c | 3 +++ fs/gfs2/inode.c | 3 +++ fs/inode.c | 30 +++++++++++++++++++++++++----- fs/orangefs/inode.c | 3 +++ fs/overlayfs/inode.c | 3 +++ fs/ubifs/file.c | 3 +++ fs/xfs/xfs_iops.c | 3 +++ include/linux/fs.h | 10 ++++++---- 9 files changed, 52 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 3ca8d294770e..7e5553878818 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -6354,6 +6354,9 @@ static int btrfs_update_time(struct inode *inode, int flags) if (btrfs_root_readonly(root)) return -EROFS; + if (flags & S_NOWAIT) + return -EAGAIN; + error = inode_update_timestamps(inode, &flags); if (error || !flags) return error; diff --git a/fs/fat/misc.c b/fs/fat/misc.c index 950da09f0961..5df3193c35f9 100644 --- a/fs/fat/misc.c +++ b/fs/fat/misc.c @@ -346,6 +346,9 @@ int fat_update_time(struct inode *inode, int flags) if (inode->i_ino == MSDOS_ROOT_INO) return 0; + if (flags & S_NOWAIT) + return -EAGAIN; + if (flags & (S_ATIME | S_CTIME | S_MTIME)) { fat_truncate_time(inode, NULL, flags); if (inode->i_sb->s_flags & SB_LAZYTIME) diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index e08eb419347c..0dce2af533b2 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -2249,6 +2249,9 @@ static int gfs2_update_time(struct inode *inode, int flags) struct gfs2_holder *gh; int error; + if (flags & S_NOWAIT) + return -EAGAIN; + gh = gfs2_glock_is_locked_by_me(gl); if (gh && gl->gl_state != LM_ST_EXCLUSIVE) { gfs2_glock_dq(gh); diff --git a/fs/inode.c b/fs/inode.c index f1c09fc0913d..0180ad526cf8 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -2110,12 +2110,26 @@ int inode_update_timestamps(struct inode *inode, int *flags) now = inode_set_ctime_current(inode); if (!timespec64_equal(&now, &ctime)) updated |= S_CTIME; - if (!timespec64_equal(&now, &mtime)) { - inode_set_mtime_to_ts(inode, now); + if (!timespec64_equal(&now, &mtime)) updated |= S_MTIME; + + if (IS_I_VERSION(inode)) { + if (*flags & S_NOWAIT) { + /* + * Error out if we'd need timestamp updates, as + * the generally requires blocking to dirty the + * inode in one form or another. + */ + if (updated && inode_iversion_need_inc(inode)) + goto bail; + } else { + if (inode_maybe_inc_iversion(inode, updated)) + updated |= S_VERSION; + } } - if (IS_I_VERSION(inode) && inode_maybe_inc_iversion(inode, updated)) - updated |= S_VERSION; + + if (updated & S_MTIME) + inode_set_mtime_to_ts(inode, now); } else { now = current_time(inode); } @@ -2131,6 +2145,9 @@ int inode_update_timestamps(struct inode *inode, int *flags) *flags = updated; return 0; +bail: + *flags = 0; + return -EAGAIN; } EXPORT_SYMBOL(inode_update_timestamps); @@ -2150,6 +2167,9 @@ int generic_update_time(struct inode *inode, int flags) { int error; + if (flags & S_NOWAIT) + return -EAGAIN; + error = inode_update_timestamps(inode, &flags); if (!error && flags) mark_inode_dirty_time(inode, flags); @@ -2378,7 +2398,7 @@ static int file_update_time_flags(struct file *file, unsigned int flags) return 0; if (flags & IOCB_NOWAIT) - return -EAGAIN; + sync_mode |= S_NOWAIT; if (mnt_get_write_access_file(file)) return 0; diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c index 3b58f31bd54f..a84142f56344 100644 --- a/fs/orangefs/inode.c +++ b/fs/orangefs/inode.c @@ -880,6 +880,9 @@ int orangefs_update_time(struct inode *inode, int flags) gossip_debug(GOSSIP_INODE_DEBUG, "orangefs_update_time: %pU\n", get_khandle_from_ino(inode)); + if (flags & S_NOWAIT) + return -EAGAIN; + error = inode_update_timestamps(inode, &flags); if (error || !flags) return error; diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index bdbf86b56a9b..28ec75994cb3 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -564,6 +564,9 @@ int ovl_update_time(struct inode *inode, int flags) .dentry = ovl_upperdentry_dereference(OVL_I(inode)), }; + if (flags & S_NOWAIT) + return -EAGAIN; + if (upperpath.dentry) { touch_atime(&upperpath); inode_set_atime_to_ts(inode, diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c index 71540644a931..fd47d0e972e2 100644 --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -1382,6 +1382,9 @@ int ubifs_update_time(struct inode *inode, int flags) if (!IS_ENABLED(CONFIG_UBIFS_ATIME_SUPPORT)) return generic_update_time(inode, flags); + if (flags & S_NOWAIT) + return -EAGAIN; + err = ubifs_budget_space(c, &req); if (err) return err; diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c index 9dedb54e3cb0..626a541b247b 100644 --- a/fs/xfs/xfs_iops.c +++ b/fs/xfs/xfs_iops.c @@ -1195,6 +1195,9 @@ xfs_vn_update_time( trace_xfs_update_time(ip); + if (flags & S_NOWAIT) + return -EAGAIN; + if (inode->i_sb->s_flags & SB_LAZYTIME) { if (!((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false))) diff --git a/include/linux/fs.h b/include/linux/fs.h index 255eb3b42d1d..34152f687b46 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2240,10 +2240,12 @@ static inline void inode_dec_link_count(struct inode *inode) } enum file_time_flags { - S_ATIME = 1, - S_MTIME = 2, - S_CTIME = 4, - S_VERSION = 8, + S_ATIME = 1U << 0, + S_MTIME = 1U << 1, + S_CTIME = 1U << 2, + S_VERSION = 1U << 3, + + S_NOWAIT = 1U << 15, }; extern bool atime_needs_update(const struct path *, struct inode *); -- 2.47.3