[PATCH v8 09/17] xfs: Report case sensitivity in fileattr_get

[Chuck Lever <cel@kernel.org>]

From: Chuck Lever <chuck.lever@oracle.com>

Upper layers such as NFSD need to query whether a filesystem is
case-sensitive. Report case sensitivity via the FS_XFLAG_CASEFOLD
flag in xfs_fileattr_get(). XFS always preserves case. XFS is
case-sensitive by default, but supports ASCII case-insensitive
lookups when formatted with the ASCIICI feature flag.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/xfs/xfs_ioctl.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 369555275140..41c6b4cd8ac2 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -518,6 +518,13 @@ xfs_fileattr_get(
 	xfs_fill_fsxattr(ip, XFS_DATA_FORK, fa);
 	xfs_iunlock(ip, XFS_ILOCK_SHARED);
 
+	/*
+	 * FS_XFLAG_CASEFOLD indicates case-insensitive lookups with
+	 * case preservation. This matches ASCIICI behavior: lookups
+	 * fold ASCII case while filenames remain stored verbatim.
+	 */
+	if (xfs_has_asciici(ip->i_mount))
+		fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
 	return 0;
 }
 
-- 
2.53.0