[PATCH v13 15/15] ksmbd: Report filesystem case sensitivity via FS_ATTRIBUTE_INFORMATION
From: Chuck Lever <cel@kernel.org>
Date: 2026-05-02 14:22:42
Also in:
linux-cifs, linux-ext4, linux-f2fs-devel, linux-fsdevel, linux-nfs, linux-xfs
Subsystem:
filesystems (vfs and infrastructure), kernel smb3 server (ksmbd), the rest · Maintainers:
Alexander Viro, Christian Brauner, Namjae Jeon, Namjae Jeon, Linus Torvalds
From: Chuck Lever <redacted> FS_ATTRIBUTE_INFORMATION responses have always reported FILE_CASE_SENSITIVE_SEARCH and FILE_CASE_PRESERVED_NAMES unconditionally. Case-insensitive filesystems like exFAT, and casefolded directories on ext4 or f2fs, have no way to signal their actual semantics to SMB clients. Now that filesystems expose case behavior through ->fileattr_get, query it via vfs_fileattr_get() and translate the FS_XFLAG_CASEFOLD and FS_XFLAG_CASENONPRESERVING flags into the corresponding SMB attributes. Filesystems without ->fileattr_get continue reporting default POSIX behavior (case-sensitive, case-preserving). SMB's FS_ATTRIBUTE_INFORMATION reports per-share attributes from the share root, not per-file. Shares mixing casefold and non-casefold directories report the root directory's behavior. Acked-by: Namjae Jeon <linkinjeon@kernel.org> Reviewed-by: Roland Mainz <redacted> Signed-off-by: Chuck Lever <redacted> --- fs/smb/server/smb2pdu.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-)
diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index ee32e61b6d3c..cf0bc453a036 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c@@ -14,6 +14,7 @@ #include <linux/falloc.h> #include <linux/mount.h> #include <linux/filelock.h> +#include <linux/fileattr.h> #include "glob.h" #include "smbfsctl.h"
@@ -5541,16 +5542,33 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work, case FS_ATTRIBUTE_INFORMATION: { FILE_SYSTEM_ATTRIBUTE_INFO *info; + struct file_kattr fa = {}; size_t sz; + u32 attrs; + int err; info = (FILE_SYSTEM_ATTRIBUTE_INFO *)rsp->Buffer; - info->Attributes = cpu_to_le32(FILE_SUPPORTS_OBJECT_IDS | - FILE_PERSISTENT_ACLS | - FILE_UNICODE_ON_DISK | - FILE_CASE_PRESERVED_NAMES | - FILE_CASE_SENSITIVE_SEARCH | - FILE_SUPPORTS_BLOCK_REFCOUNTING); + attrs = FILE_SUPPORTS_OBJECT_IDS | + FILE_PERSISTENT_ACLS | + FILE_UNICODE_ON_DISK | + FILE_SUPPORTS_BLOCK_REFCOUNTING; + err = vfs_fileattr_get(path.dentry, &fa); + /* + * -EINVAL, -EOPNOTSUPP: ntfs-3g and other FUSE + * filesystems that lack FS_IOC_FSGETXATTR support. + */ + if (err && err != -ENOIOCTLCMD && err != -ENOTTY && + err != -EINVAL && err != -EOPNOTSUPP) { + path_put(&path); + return err; + } + if (!(fa.fsx_xflags & FS_XFLAG_CASEFOLD)) + attrs |= FILE_CASE_SENSITIVE_SEARCH; + if (!(fa.fsx_xflags & FS_XFLAG_CASENONPRESERVING)) + attrs |= FILE_CASE_PRESERVED_NAMES; + + info->Attributes = cpu_to_le32(attrs); info->Attributes |= cpu_to_le32(server_conf.share_fake_fscaps); if (test_share_config_flag(work->tcon->share_conf,
--
2.53.0