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Message-ID: <20260122160311.1117669-2-cel@kernel.org>
Date: Thu, 22 Jan 2026 11:02:56 -0500
From: Chuck Lever <cel@...nel.org>
To: Al Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>,
Jan Kara <jack@...e.cz>
Cc: <linux-fsdevel@...r.kernel.org>,
linux-ext4@...r.kernel.org,
linux-xfs@...r.kernel.org,
linux-cifs@...r.kernel.org,
<linux-nfs@...r.kernel.org>,
linux-api@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net,
hirofumi@...l.parknet.co.jp,
linkinjeon@...nel.org,
sj1557.seo@...sung.com,
yuezhang.mo@...y.com,
almaz.alexandrovich@...agon-software.com,
slava@...eyko.com,
glaubitz@...sik.fu-berlin.de,
frank.li@...o.com,
tytso@....edu,
adilger.kernel@...ger.ca,
cem@...nel.org,
sfrench@...ba.org,
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sprasad@...rosoft.com,
trondmy@...nel.org,
anna@...nel.org,
jaegeuk@...nel.org,
chao@...nel.org,
hansg@...nel.org,
senozhatsky@...omium.org,
Chuck Lever <chuck.lever@...cle.com>
Subject: [PATCH v7 01/16] fs: Add case sensitivity flags to file_kattr
From: Chuck Lever <chuck.lever@...cle.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. These flags are read-only; userspace cannot set
them via ioctl.
Remove struct file_kattr initialization from fileattr_fill_xflags()
and fileattr_fill_flags(). Callers at ioctl/syscall entry points
zero-initialize the struct themselves, which allows them to pass
hints (flags_valid, fsx_valid) to the filesystem's ->fileattr_get()
callback via the fa argument. Filesystem handlers that invoke these
fill functions can now set flags directly in fa->fsx_xflags before
calling them, without the fill functions zeroing those values.
Case sensitivity information is exported to userspace via the
fa_xflags field in the FS_IOC_FSGETXATTR ioctl and file_getattr()
system call.
Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
---
fs/file_attr.c | 12 ++++--------
fs/xfs/xfs_ioctl.c | 2 +-
include/linux/fileattr.h | 3 ++-
include/uapi/linux/fs.h | 2 ++
4 files changed, 9 insertions(+), 10 deletions(-)
diff --git a/fs/file_attr.c b/fs/file_attr.c
index 13cdb31a3e94..6e37040fc5fa 100644
--- a/fs/file_attr.c
+++ b/fs/file_attr.c
@@ -15,12 +15,10 @@
* @fa: fileattr pointer
* @xflags: FS_XFLAG_* flags
*
- * Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags). All
- * other fields are zeroed.
+ * Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags).
*/
void fileattr_fill_xflags(struct file_kattr *fa, u32 xflags)
{
- memset(fa, 0, sizeof(*fa));
fa->fsx_valid = true;
fa->fsx_xflags = xflags;
if (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)
@@ -46,11 +44,9 @@ EXPORT_SYMBOL(fileattr_fill_xflags);
* @flags: FS_*_FL flags
*
* Set ->flags, ->flags_valid and ->fsx_xflags (translated flags).
- * All other fields are zeroed.
*/
void fileattr_fill_flags(struct file_kattr *fa, u32 flags)
{
- memset(fa, 0, sizeof(*fa));
fa->flags_valid = true;
fa->flags = flags;
if (fa->flags & FS_SYNC_FL)
@@ -323,7 +319,7 @@ int ioctl_setflags(struct file *file, unsigned int __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
- struct file_kattr fa;
+ struct file_kattr fa = {};
unsigned int flags;
int err;
@@ -355,7 +351,7 @@ int ioctl_fssetxattr(struct file *file, void __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
- struct file_kattr fa;
+ struct file_kattr fa = {};
int err;
err = copy_fsxattr_from_user(&fa, argp);
@@ -434,7 +430,7 @@ SYSCALL_DEFINE5(file_setattr, int, dfd, const char __user *, filename,
struct filename *name __free(putname) = NULL;
unsigned int lookup_flags = 0;
struct file_attr fattr;
- struct file_kattr fa;
+ struct file_kattr fa = {};
int error;
BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0);
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 59eaad774371..f0417c4d1fca 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -496,7 +496,7 @@ xfs_ioc_fsgetxattra(
xfs_inode_t *ip,
void __user *arg)
{
- struct file_kattr fa;
+ struct file_kattr fa = {};
xfs_ilock(ip, XFS_ILOCK_SHARED);
xfs_fill_fsxattr(ip, XFS_ATTR_FORK, &fa);
diff --git a/include/linux/fileattr.h b/include/linux/fileattr.h
index f89dcfad3f8f..709de829659f 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_PREALLOC | FS_XFLAG_HASATTR | \
+ 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 66ca526cf786..919148beaa8c 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -253,6 +253,8 @@ struct file_attr {
#define FS_XFLAG_FILESTREAM 0x00004000 /* use filestream allocator */
#define FS_XFLAG_DAX 0x00008000 /* use DAX for IO */
#define FS_XFLAG_COWEXTSIZE 0x00010000 /* CoW extent size allocator hint */
+#define FS_XFLAG_CASEFOLD 0x00020000 /* case-insensitive lookups */
+#define FS_XFLAG_CASENONPRESERVING 0x00040000 /* 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
--
2.52.0
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