[PATCH v13 02/15] fs: Add case sensitivity flags to file_kattr
From: Chuck Lever <cel@kernel.org>
Date: 2026-05-02 14:21:24
Also in:
linux-cifs, linux-ext4, linux-f2fs-devel, linux-fsdevel, linux-nfs, linux-xfs
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Chuck Lever <chuck.lever@oracle.com> Enable upper layers such as NFSD to retrieve case sensitivity information from file systems by adding FS_XFLAG_CASEFOLD and FS_XFLAG_CASENONPRESERVING flags. Filesystems report case-insensitive or case-nonpreserving behavior by setting these flags directly in fa->fsx_xflags. The default (flags unset) indicates POSIX semantics: case-sensitive and case-preserving. Both flags are added to FS_XFLAG_RDONLY_MASK so FS_IOC_FSSETXATTR silently strips them, keeping the new xflags strictly a reporting interface. Callers that want to toggle casefolding continue to use FS_IOC_SETFLAGS with FS_CASEFOLD_FL, the established UAPI on filesystems that support the operation (ext4 and f2fs on empty directories). Case sensitivity information is exported to userspace via the fa_xflags field in the FS_IOC_FSGETXATTR ioctl and file_getattr() system call. Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Roland Mainz <redacted> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> --- fs/file_attr.c | 4 ++++ include/linux/fileattr.h | 3 ++- include/uapi/linux/fs.h | 7 +++++++ 3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/fs/file_attr.c b/fs/file_attr.c
index f429da66a317..bfb00d256dd5 100644
--- a/fs/file_attr.c
+++ b/fs/file_attr.c@@ -37,6 +37,8 @@ void fileattr_fill_xflags(struct file_kattr *fa, u32 xflags) fa->flags |= FS_PROJINHERIT_FL; if (fa->fsx_xflags & FS_XFLAG_VERITY) fa->flags |= FS_VERITY_FL; + if (fa->fsx_xflags & FS_XFLAG_CASEFOLD) + fa->flags |= FS_CASEFOLD_FL; } EXPORT_SYMBOL(fileattr_fill_xflags);
@@ -67,6 +69,8 @@ void fileattr_fill_flags(struct file_kattr *fa, u32 flags) fa->fsx_xflags |= FS_XFLAG_PROJINHERIT; if (fa->flags & FS_VERITY_FL) fa->fsx_xflags |= FS_XFLAG_VERITY; + if (fa->flags & FS_CASEFOLD_FL) + fa->fsx_xflags |= FS_XFLAG_CASEFOLD; } EXPORT_SYMBOL(fileattr_fill_flags);
diff --git a/include/linux/fileattr.h b/include/linux/fileattr.h
index 3780904a63a6..58044b598016 100644
--- a/include/linux/fileattr.h
+++ b/include/linux/fileattr.h@@ -16,7 +16,8 @@ /* Read-only inode flags */ #define FS_XFLAG_RDONLY_MASK \ - (FS_XFLAG_PREALLOC | FS_XFLAG_HASATTR | FS_XFLAG_VERITY) + (FS_XFLAG_PREALLOC | FS_XFLAG_HASATTR | FS_XFLAG_VERITY | \ + FS_XFLAG_CASEFOLD | FS_XFLAG_CASENONPRESERVING) /* Flags to indicate valid value of fsx_ fields */ #define FS_XFLAG_VALUES_MASK \
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 13f71202845e..2ea4c81df08f 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h@@ -254,6 +254,13 @@ struct file_attr { #define FS_XFLAG_DAX 0x00008000 /* use DAX for IO */ #define FS_XFLAG_COWEXTSIZE 0x00010000 /* CoW extent size allocator hint */ #define FS_XFLAG_VERITY 0x00020000 /* fs-verity enabled */ +/* + * Case handling flags (read-only, cannot be set via ioctl). + * Default (neither set) indicates POSIX semantics: case-sensitive + * lookups and case-preserving storage. + */ +#define FS_XFLAG_CASEFOLD 0x00040000 /* case-insensitive lookups */ +#define FS_XFLAG_CASENONPRESERVING 0x00080000 /* case not preserved */ #define FS_XFLAG_HASATTR 0x80000000 /* no DIFLAG for this */ /* the read-only stuff doesn't really belong here, but any other place is
--
2.53.0