From: Chuck Lever Date: Fri, 15 May 2026 15:35:12 +0000 (-0400) Subject: fs: Clarify FS_CASEFOLD_FL semantics in UAPI header X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=45e57cfb7b10b64fb0d38d671d26ec935fc7efce;p=thirdparty%2Flinux.git fs: Clarify FS_CASEFOLD_FL semantics in UAPI header The existing one-liner "Folder is case insensitive" leaves the impression that FS_CASEFOLD_FL is reserved for directories. That impression is wrong: filesystems that derive case-insensitivity from mount or volume state report the bit on non-directory inodes via i_op->fileattr_get, so userspace inspecting FS_IOC_GETFLAGS can see it on any inode type. Replace the one-liner with a block comment that names directories as the typical case, records that non-directory inodes may also report the bit, and notes FS_XFLAG_CASEFOLD as the read-only companion exposed through FS_IOC_FSGETXATTR. Reported-by: sashiko-bot Closes: https://sashiko.dev/#/patchset/20260507-case-sensitivity-v14-0-e62cc8200435@oracle.com?part=3 Signed-off-by: Chuck Lever Link: https://patch.msgid.link/20260515153515.362266-5-cel@kernel.org Signed-off-by: Christian Brauner --- diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 2ea4c81df08f1..bd87262f2e349 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -395,7 +395,16 @@ struct file_attr { #define FS_DAX_FL 0x02000000 /* Inode is DAX */ #define FS_INLINE_DATA_FL 0x10000000 /* Reserved for ext4 */ #define FS_PROJINHERIT_FL 0x20000000 /* Create with parents projid */ -#define FS_CASEFOLD_FL 0x40000000 /* Folder is case insensitive */ +/* + * FS_CASEFOLD_FL indicates case-insensitive name lookup. The + * bit is most often reported on directories, where it controls + * lookups of entries within. Filesystems that derive + * case-insensitivity from mount or volume state may also report + * it on non-directory inodes; userspace must not assume the bit + * is directory-only. FS_XFLAG_CASEFOLD reports the same + * information read-only via FS_IOC_FSGETXATTR. + */ +#define FS_CASEFOLD_FL 0x40000000 #define FS_RESERVED_FL 0x80000000 /* reserved for ext2 lib */ #define FS_FL_USER_VISIBLE 0x0003DFFF /* User visible flags */