From mboxrd@z Thu Jan 1 00:00:00 1970 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 6BA14346AE3; Wed, 22 Apr 2026 23:30:17 +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=1776900617; cv=none; b=hrBvZSaVQUbgx8aBN2giyXYPL8WdmBnZ4+2uScJWAzmI8Osv/uPdDzMaEt2puldP+QGlB8IM+ka7GW+Pl8iGq34DqZQqs/FlZ3SLbiIK5LdN39Ob9kPgG7Slj8ZjKOnN+ipn5r5iiy/znyvU21Q6boRMtUQ86JIQ7cQ2BIFJXlI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776900617; c=relaxed/simple; bh=nSWvRvVLvvSZdli9CnC8hr1bXPfPcgp+ZC3UK68WE7E=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=Nd2gWYMS3GKNOZNUOl9ebDaSBuumZjML2ooQB7aGDUNytmyWUQuIXP+W3sFTGqMkkqivVe5iaVLSSy7DqRA6/GQCyGx13KIYW8uoOuhOapVTn9s0fwBhDkmMXDt+7vYoPcgdax0Qrc1D25SLd2EUO7mnE+iJRPOVS4JS8CHKwAo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=N6+HGFyh; 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="N6+HGFyh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1496C19425; Wed, 22 Apr 2026 23:30:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776900617; bh=nSWvRvVLvvSZdli9CnC8hr1bXPfPcgp+ZC3UK68WE7E=; h=From:Subject:Date:To:Cc:From; b=N6+HGFyhQd9DvW78jZtWY1QbnbgcQhKYbdv/Pr4g7qkRM9M1dt3zSDjvsq8+Cj6Pq /fYZRkpRRSxhtTiitiM6p0xyWllr8bgvYNLbg2S1HyHzztErbjiK8wJC9x+QtQWJzG jbGrbNjAcP3LB5fQiQVh5B9pu1AHdqSUOw6cmWYPtwbfHS9q0GIH7T812IUuRi0Fh8 +Trv4GBlAhj7ISIQGWim7FoG76jC1fYOG+Eiv9DUQyKg4lsQ+KLXMaKOI6ovh2t4gS vJODnaQhSbNkc3kC5p1owoayosmQoqWLeTZOFy3SKWxoOY5peKpHkibCTXvOefNHFs 1hO1Xuq4ZpY4g== From: Chuck Lever Subject: [PATCH v9 00/17] Exposing case folding behavior Date: Wed, 22 Apr 2026 19:29:54 -0400 Message-Id: <20260422-case-sensitivity-v9-0-be023cc070e2@oracle.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAPJZ6WkC/yWMQQ7CMAwEv1L5TEqJKBS+gjgkrk2NUIriEIGq/ p0EDnuY1e4soBSFFM7NApGyqMyhwGnTAE4u3MjIWBhsZw/d3lqDTskoBZUkWdLH9OiZceBd3w9 Qbs9ILO+f8nL9s778nTBVT134qvDRBZxqlVm3JebY2rbaeX6MsK5f7o3QmpsAAAA= X-Change-ID: 20260422-case-sensitivity-5cbffc8f1558 To: Al Viro , Christian Brauner , Jan Kara Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-api@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, hirofumi@mail.parknet.co.jp, linkinjeon@kernel.org, sj1557.seo@samsung.com, yuezhang.mo@sony.com, almaz.alexandrovich@paragon-software.com, slava@dubeyko.com, glaubitz@physik.fu-berlin.de, frank.li@vivo.com, tytso@mit.edu, adilger.kernel@dilger.ca, cem@kernel.org, sfrench@samba.org, pc@manguebit.org, ronniesahlberg@gmail.com, sprasad@microsoft.com, trondmy@kernel.org, anna@kernel.org, jaegeuk@kernel.org, chao@kernel.org, hansg@kernel.org, senozhatsky@chromium.org, Chuck Lever , "Darrick J. Wong" X-Mailer: b4 0.16-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=6855; i=chuck.lever@oracle.com; h=from:subject:message-id; bh=nSWvRvVLvvSZdli9CnC8hr1bXPfPcgp+ZC3UK68WE7E=; b=owEBbQKS/ZANAwAKATNqszNvZn+XAcsmYgBp6Vn9Kt1tzr2kFvP0Kdpok68GcrcKfLlwgFtsM oazIO8Ul9SJAjMEAAEKAB0WIQQosuWwEobfJDzyPv4zarMzb2Z/lwUCaelZ/QAKCRAzarMzb2Z/ l9QQD/0cnxc2xWUgbGlmzr0CatU2yPuq86+5240DgMd1JmcaJt9CAna3J70eXcj3QgfuPQKTKRV 6Wj4NTvZq48eV9gFyX4EIbWUzlkuQdgMaxxQZeq/avJeilSwdxJqsg/CQx6VEevXvlW2bCEiWpy GK4Scn4yMuj5Wu04CyGzjvh8ySvjSmjJjCwzeSiT4rI5hUIFNmVXu7ywVgMmVemz7TVVXZjErFP +xFdr4I9IcMOJVA6scAtzMnFO7vFs40YtiVPkSfCQYle/w3k0FKqpGEMVueH75kl/Jaaxn8wkzv W1lY/B9IqCTW4NdG6Qd4ZaaCr+wnHwNxgzuYXfBqRWt/uYrCs1SH554zHYsStczLnFEAEg0y2P7 Ck6/isIXfTB5tYlVfBL44MRKfNDDhtyZoqfzhgqnqzBtNNIk+GZouAD4qqjWYlWCoTNC242b9IN 713gzqezLN8ax2i1d1cUKZCcXz2e6V4a6Th1VxD1u15I918Ba0wQXowjwKf/CmCj0e5A2VmqP+N k75pCnONxAWYNGk545R71I+qwLpexoxkyKhnn+u3VQlVk1djoK6aQ8xA+K9njqvvUb4drZVPULh w9BWIIwK9SgO06IGf9WwP4tf/SXkjGH1YnzYzcmMfWlONfvUoalk1OQnGZd1hBhwVs79ZFG+6YD WNaMOCAe6Hb566Q== X-Developer-Key: i=chuck.lever@oracle.com; a=openpgp; fpr=28B2E5B01286DF243CF23EFE336AB3336F667F97 Following on from https://lore.kernel.org/linux-nfs/20251021-zypressen-bazillus-545a44af57fd@brauner/T/#m0ba197d75b7921d994cf284f3cef3a62abb11aaa I'm attempting to implement enough support in the Linux VFS to enable file services like NFSD and ksmbd (and user space equivalents) to provide the actual status of case folding support in local file systems. The default behavior for local file systems not explicitly supported in this series is to reflect the usual POSIX behaviors: case-insensitive = false case-nonpreserving = false The case-insensitivity and case-nonpreserving booleans can be consumed immediately by NFSD. These two attributes have been part of the NFSv3 and NFSv4 protocols for decades, in order to support NFS client implementations on non-POSIX systems. Support for user space file servers is why this series exposes case folding information via a user-space API. I don't know of any other category of user-space application that requires access to case folding info. The Linux NFS community has a growing interest in supporting NFS clients on Windows and MacOS platforms, where file name behavior does not align with traditional POSIX semantics. One example of a Windows-based NFS client is [1]. This client implementation explicitly requires servers to report FATTR4_WORD0_CASE_INSENSITIVE = TRUE for proper operation, a hard requirement for Windows client interoperability because Windows applications expect case-insensitive behavior. When an NFS client knows the server is case-insensitive, it can avoid issuing multiple LOOKUP/READDIR requests to search for case variants, and applications like Win32 programs work correctly without manual workarounds or code changes. Even the Linux client can take advantage of this information. Trond merged patches 4 years ago [2] that introduce support for case insensitivity, in support of the Hammerspace NFS server. In particular, when a client detects a case-insensitive NFS share, negative dentry caching must be disabled (a lookup for "FILE.TXT" failing shouldn't cache a negative entry when "file.txt" exists) and directory change invalidation must clear all cached case-folded file name variants. Hammerspace servers and several other NFS server implementations operate in multi-protocol environments, where a single file service instance caters to both NFS and SMB clients. In those cases, things work more smoothly for everyone when the NFS client can see and adapt to the case folding behavior that SMB users rely on and expect. NFSD needs to support the case-insensitivity and case-nonpreserving booleans properly in order to participate as a first-class citizen in such environments. [1] https://github.com/kofemann/ms-nfs41-client [2] https://patchwork.kernel.org/project/linux-nfs/cover/20211217203658.439352-1-trondmy@kernel.org/ --- Changes since v8: - Rebase on v7.0-rc1 Changes since v7: - Split file_attr initialization changes into a separate patch Changes since v6: - Remove the memset from vfs_fileattr_get Changes since v5: - Finish the conversion to FS_XFLAGs - NFSv4 GETATTR now clears the attr mask bit if nfsd_get_case_info() fails Changes since v4: - Observe the MSDOS "nocase" mount option - Define new FS_XFLAGs for the user API Changes since v3: - Change fa->case_preserving to fa_case_nonpreserving - VFAT is case preserving - Make new fields available to user space Changes since v2: - Remove unicode labels - Replace vfs_get_case_info - Add support for several more local file system implementations - Add support for in-kernel SMB server Changes since RFC: - Use file_getattr instead of statx - Postpone exposing Unicode version until later - Support NTFS and ext4 in addition to FAT - Support NFSv4 fattr4 in addition to NFSv3 PATHCONF --- Chuck Lever (17): fs: Move file_kattr initialization to callers fs: Add case sensitivity flags to file_kattr fat: Implement fileattr_get for case sensitivity exfat: Implement fileattr_get for case sensitivity ntfs3: Implement fileattr_get for case sensitivity hfs: Implement fileattr_get for case sensitivity hfsplus: Report case sensitivity in fileattr_get ext4: Report case sensitivity in fileattr_get xfs: Report case sensitivity in fileattr_get cifs: Implement fileattr_get for case sensitivity nfs: Implement fileattr_get for case sensitivity f2fs: Add case sensitivity reporting to fileattr_get vboxsf: Implement fileattr_get for case sensitivity isofs: Implement fileattr_get for case sensitivity nfsd: Report export case-folding via NFSv3 PATHCONF nfsd: Implement NFSv4 FATTR4_CASE_INSENSITIVE and FATTR4_CASE_PRESERVING ksmbd: Report filesystem case sensitivity via FS_ATTRIBUTE_INFORMATION fs/exfat/exfat_fs.h | 2 ++ fs/exfat/file.c | 17 +++++++++++++++-- fs/exfat/namei.c | 1 + fs/ext4/ioctl.c | 7 +++++++ fs/f2fs/file.c | 8 ++++++++ fs/fat/fat.h | 3 +++ fs/fat/file.c | 23 +++++++++++++++++++++++ fs/fat/namei_msdos.c | 1 + fs/fat/namei_vfat.c | 1 + fs/file_attr.c | 16 ++++++++-------- fs/hfs/dir.c | 1 + fs/hfs/hfs_fs.h | 2 ++ fs/hfs/inode.c | 13 +++++++++++++ fs/hfsplus/inode.c | 10 ++++++++++ fs/isofs/dir.c | 11 +++++++++++ fs/nfs/client.c | 9 +++++++-- fs/nfs/inode.c | 21 +++++++++++++++++++++ fs/nfs/internal.h | 3 +++ fs/nfs/nfs3proc.c | 2 ++ fs/nfs/nfs3xdr.c | 7 +++++-- fs/nfs/nfs4proc.c | 2 ++ fs/nfs/proc.c | 3 +++ fs/nfs/symlink.c | 3 +++ fs/nfsd/nfs3proc.c | 18 ++++++++++-------- fs/nfsd/nfs4xdr.c | 25 +++++++++++++++++++++++-- fs/nfsd/vfs.c | 29 +++++++++++++++++++++++++++++ fs/nfsd/vfs.h | 3 +++ fs/ntfs3/file.c | 23 +++++++++++++++++++++++ fs/ntfs3/inode.c | 1 + fs/ntfs3/namei.c | 2 ++ fs/ntfs3/ntfs_fs.h | 1 + fs/smb/client/cifsfs.c | 20 ++++++++++++++++++++ fs/smb/server/smb2pdu.c | 25 +++++++++++++++++++------ fs/vboxsf/dir.c | 1 + fs/vboxsf/file.c | 6 ++++-- fs/vboxsf/super.c | 7 +++++++ fs/vboxsf/utils.c | 26 ++++++++++++++++++++++++++ fs/vboxsf/vfsmod.h | 6 ++++++ fs/xfs/xfs_ioctl.c | 9 ++++++++- include/linux/fileattr.h | 3 ++- include/linux/nfs_xdr.h | 2 ++ include/uapi/linux/fs.h | 7 +++++++ 42 files changed, 346 insertions(+), 34 deletions(-) --- base-commit: 6596a02b207886e9e00bb0161c7fd59fea53c081 change-id: 20260422-case-sensitivity-5cbffc8f1558 Best regards, -- Chuck Lever