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 31594199FAB; Sat, 25 Apr 2026 01:53:24 +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=1777082004; cv=none; b=EJqgv+Ti3qaHkbtJSXBJEsnnoz56/16p3eUFcWRdkLYowhUrt+VT02AdCr6j7RfCMfJosdL9IMUmBywSL3+t1I2ceAtb2PKdE7hgqrTGPZIXeAvfsJE78A5Ar2tXqqkcVR1IqqCMwTdr7K54yJCvO0G80VFT3CpTNi2iAGAKIJQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777082004; c=relaxed/simple; bh=qvbC5NlYJmq/Ki8T76bjgsnV+oxegfIoPZjnm5RLKp0=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=VzywwjQPFaIc2KjmuNW0ttHISgFvJl/ohBhaP4TfPBgFxXhvMoHcMkupyTlrF0VkypM3cI//J+7Mr1pxPTANEtFWaEhDjBPMTdp2ct3soU8jJhoNSr7eAcFr5XbONr0lTVzkbh5sOnrMncDKKyfTtntJmsnBNwYKKwzcYxZY3oU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=obe7iRq/; 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="obe7iRq/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DBE0C19425; Sat, 25 Apr 2026 01:53:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777082003; bh=qvbC5NlYJmq/Ki8T76bjgsnV+oxegfIoPZjnm5RLKp0=; h=From:Subject:Date:To:Cc:From; b=obe7iRq/78V4hlxas+M4IIY2ietF4Re1Q5+/0Zv3hpkpLObsrB096NwkS69HKH/W0 rDucRPzvRkf/MpvZtDIoZTClP4f0bG58Vhmi6BQVE9UgYju8aQmyqwPtu5PuqvKC7N mt4cOSSIYMRlUS+4AkHrx593m02Nd66ysnKeOePU7HDX5Q5n8+rm2DrGV2c/fFT5sc CRi6d+AfwuQmQoTlzYaejf1Xqz0vsqJe3aQb5MFnUtSqfSUCJKDxzZ+j7eZP4cFDr4 jBFXhY87/O2DZJqyr8sU/RibGXgGM80I39VH+CEMzB6G51RkuufduwhuMtU8rY5paY flqqoWdGLybyQ== From: Chuck Lever Subject: [PATCH v11 00/15] Exposing case folding behavior Date: Fri, 24 Apr 2026 21:53:02 -0400 Message-Id: <20260424-case-sensitivity-v11-0-de5619beddaf@oracle.com> Precedence: bulk X-Mailing-List: linux-api@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=H4sIAH4e7GkC/33OTY7CMAwF4KugrElJUvoDK+6BZpG4DjVimlFco kGod5+E2YCEWHhh6/nTuwvGSMhiv7qLiImYwpQXrdcrAaOdTihpyAdhlGnV1hgJllEyTkwzJZp vsgHnPfReN00v8ttPRE+/D/P49b/z1Z0R5uKUhCuEi3aCsZyS500e2VWmKroPl6HERuI5xNujW 9oV7kOLtJNKOlSmBlCdQnMI0cIFKwjfotRIWj0T9RtCq2xA3TdD221tC/7FWJblD2SwXuQvAQA A 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" , Roland Mainz , Steve French X-Mailer: b4 0.16-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=9166; i=chuck.lever@oracle.com; h=from:subject:message-id; bh=qvbC5NlYJmq/Ki8T76bjgsnV+oxegfIoPZjnm5RLKp0=; b=owEBbQKS/ZANAwAKATNqszNvZn+XAcsmYgBp7B6H5jdQVrURdMJvzvrzrIyiUSlrW5F2+jU/R Siuyfo+iJGJAjMEAAEKAB0WIQQosuWwEobfJDzyPv4zarMzb2Z/lwUCaewehwAKCRAzarMzb2Z/ l+X+EACyaFUfr4QKWt5y0e34mlhjRMJ16e/r6VqqsKyfiVX49EWNfI1+fqQWN7crSb2JyzkDiwQ TfmMenKRLJq6gn07kayO2ke6tBRF7EGXKjpoOWiHnblh2mxCnSJnsrfi3qlUeoYiIbBnNU/odye aay7Oc1lPC5H20togSfavnVmmpL2YYlnMH2EHnGU2L4LZChunD0/IfYWPZax+Upd1XEXJzT7TzN 25jsYLE1wQt1t3z8nrIzwP5ENjONsjU+orBswHvwDsAkAyZ10JnsKXMi875QkAzfPH1ULUYMjVt w1AnXZiQmYJJVYIUm4X4UcCkOZr9s18estxDSKJKreNbc5QgKZcRbDjxcl/dnat5A1X3DfPU6hU DokgoXGqFpPBJtt7VUTWxdL5wvB4g0FClIfhU9fvM71H1A5gHngve5yLMY7JkaElkZU41BZBdeb OeDHaOayluNaZzoEF+SziM2r/tMuvFIo3Va6sZijT5hePfU/Hl8VnnIYaTM0XSc2ogZ95Slnxjd V+PQIA0xMrGPjcOHbrhSimiga/tCwSZEGn1MSy6JbEoJIkYyR3MjyNf6LjmR1XQoKmrKUm+FRz8 bf9kUal3P0vjZYUaZFdstuL7nbIcSXkNYHplWmtJM7j1kxH33LxE4QIlmgBvftE/d3zYWzCU5cw A7/Qq0k/0kXGePQ== 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 v10: - cifs: Source case-handling flags from the server's cached FS_ATTRIBUTE_INFORMATION reply instead of the nocase mount option, with a nocase fallback when the reply is absent - Address findings from sashiko(gemini-3) and gpt-5.5: - nfs: Skip pathconf case bits on NFSv4 (set via FATTR4_CASE_* instead) - xfs: Hide FS_CASEFOLD_FL from the legacy flags view so chattr round-trips do not hit the setflags whitelist - ext4, f2fs: Drop redundant fileattr_get patches; the FS_CASEFOLD_FL translation in fileattr_fill_flags() already reports FS_XFLAG_CASEFOLD for casefolded directories - nfsd: Report FATTR4_HOMOGENEOUS = FALSE when the exported filesystem has a Unicode encoding, since per-directory casefold makes the fs-scoped case attributes inhomogeneous - nfsd: Document in nfsd_get_case_info() why -ENOIOCTLCMD and -ENOTTY are swallowed while other errors propagate - fat: Honor vfat 'check=strict' when reporting FS_XFLAG_CASEFOLD - Set FS_CASEFOLD_FL so FS_IOC_GETFLAGS reflects case-insensitive mount - isofs: Register fileattr_get on regular file and symlink inodes, not just directories - nfsd: Query NFSv4 FATTR4_CASE_* from the parent directory for non-directory objects, since casefold lives on the directory Changes since v9: - nfs: always probe PATHCONF for case caps. Default to case- preserving when the server does not report case_preserving - nfsd, ksmbd: tolerate -ENOTTY from vfs_fileattr_get() so overlayfs exports on backing filesystems without fileattr_get do not fail the RPC - xfs: map FS_XFLAG_CASEFOLD inside xfs_ip2xflags() so BULKSTAT and FS_IOC_FSGETXATTR report the flag consistently - vboxsf: reject a short host reply to SHFL_INFO_VOLUME before trusting volinfo.properties.case_sensitive 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 --- Changes in v11: - EDITME: describe what is new in this series revision. - EDITME: use bulletpoints and terse descriptions. - Link to v10: https://patch.msgid.link/20260423-case-sensitivity-v10-0-c385d674a6cf@oracle.com --- Chuck Lever (15): 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 xfs: Report case sensitivity in fileattr_get cifs: Implement fileattr_get for case sensitivity nfs: Implement fileattr_get for case sensitivity 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 | 18 ++++++++++++-- fs/exfat/namei.c | 1 + fs/fat/fat.h | 3 +++ fs/fat/file.c | 32 ++++++++++++++++++++++++ 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 | 14 +++++++++++ fs/hfsplus/inode.c | 12 +++++++++ fs/isofs/dir.c | 24 ++++++++++++++++++ fs/isofs/inode.c | 3 ++- fs/isofs/isofs.h | 5 ++++ fs/nfs/client.c | 22 +++++++++++++---- fs/nfs/inode.c | 23 ++++++++++++++++++ fs/nfs/internal.h | 3 +++ fs/nfs/nfs3proc.c | 2 ++ fs/nfs/nfs3xdr.c | 7 ++++-- fs/nfs/nfs4proc.c | 7 ++++-- fs/nfs/proc.c | 3 +++ fs/nfs/symlink.c | 3 +++ fs/nfsd/nfs3proc.c | 18 ++++++++------ fs/nfsd/nfs4xdr.c | 55 +++++++++++++++++++++++++++++++++++++++--- fs/nfsd/vfs.c | 43 +++++++++++++++++++++++++++++++++ fs/nfsd/vfs.h | 3 +++ fs/ntfs3/file.c | 25 +++++++++++++++++++ fs/ntfs3/inode.c | 1 + fs/ntfs3/namei.c | 2 ++ fs/ntfs3/ntfs_fs.h | 1 + fs/smb/client/cifsfs.c | 42 ++++++++++++++++++++++++++++++++ fs/smb/server/smb2pdu.c | 30 ++++++++++++++++++----- fs/vboxsf/dir.c | 1 + fs/vboxsf/file.c | 6 +++-- fs/vboxsf/super.c | 7 ++++++ fs/vboxsf/utils.c | 30 +++++++++++++++++++++++ fs/vboxsf/vfsmod.h | 6 +++++ fs/xfs/libxfs/xfs_inode_util.c | 2 ++ fs/xfs/xfs_ioctl.c | 9 ++++++- include/linux/fileattr.h | 3 ++- include/linux/nfs_fs_sb.h | 2 +- include/linux/nfs_xdr.h | 2 ++ include/uapi/linux/fs.h | 7 ++++++ 44 files changed, 458 insertions(+), 42 deletions(-) --- base-commit: 6596a02b207886e9e00bb0161c7fd59fea53c081 change-id: 20260422-case-sensitivity-5cbffc8f1558 Best regards, -- Chuck Lever