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.
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| @@ -395,7 +395,16 @@ struct file_attr { · 394 unmodified lines | ||
| 395 | 395 | #define FS_DAX_FL 0x02000000 /* Inode is DAX */ |
| 396 | 396 | #define FS_INLINE_DATA_FL 0x10000000 /* Reserved for ext4 */ |
| 397 | 397 | #define FS_PROJINHERIT_FL 0x20000000 /* Create with parents projid */ |
| 398 | −#define FS_CASEFOLD_FL 0x40000000 /* Folder is case insensitive */ | |
| 398 | +/* | |
| 399 | + * FS_CASEFOLD_FL indicates case-insensitive name lookup. The | |
| 400 | + * bit is most often reported on directories, where it controls | |
| 401 | + * lookups of entries within. Filesystems that derive | |
| 402 | + * case-insensitivity from mount or volume state may also report | |
| 403 | + * it on non-directory inodes; userspace must not assume the bit | |
| 404 | + * is directory-only. FS_XFLAG_CASEFOLD reports the same | |
| 405 | + * information read-only via FS_IOC_FSGETXATTR. | |
| 406 | + */ | |
| 407 | +#define FS_CASEFOLD_FL 0x40000000 | |
| 399 | 408 | #define FS_RESERVED_FL 0x80000000 /* reserved for ext2 lib */ |
| 400 | 409 | |
| 401 | 410 | #define FS_FL_USER_VISIBLE 0x0003DFFF /* User visible flags */ |