[PATCH v8 10/17] cifs: Implement fileattr_get for case sensitivity
From: Chuck Lever <cel@kernel.org>
Date: 2026-02-17 21:48:11
Also in:
linux-cifs, linux-ext4, linux-f2fs-devel, linux-fsdevel, linux-nfs, linux-xfs
Subsystem:
common internet file system client (cifs and smb3), filesystems (vfs and infrastructure), the rest · Maintainers:
Steve French, Alexander Viro, Christian Brauner, Linus Torvalds
From: Chuck Lever <chuck.lever@oracle.com> Upper layers such as NFSD need a way to query whether a filesystem handles filenames in a case-sensitive manner. Report CIFS/SMB case handling behavior via the FS_XFLAG_CASEFOLD flag. CIFS servers (typically Windows or Samba) are usually case-insensitive but case-preserving, meaning they ignore case during lookups but store filenames exactly as provided. The implementation reports case sensitivity based on the nocase mount option, which reflects whether the client expects the server to perform case-insensitive comparisons. When nocase is set, the mount is reported as case-insensitive. The callback is registered in all three inode_operations structures (directory, file, and symlink) to ensure consistent reporting across all inode types. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> --- fs/smb/client/cifsfs.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index afda1d7c1ee1..9d85785a1c67 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c@@ -30,6 +30,7 @@ #include <linux/xattr.h> #include <linux/mm.h> #include <linux/key-type.h> +#include <linux/fileattr.h> #include <uapi/linux/magic.h> #include <net/ipv6.h> #include "cifsfs.h"
@@ -1189,6 +1190,22 @@ struct file_system_type smb3_fs_type = { MODULE_ALIAS_FS("smb3"); MODULE_ALIAS("smb3"); +static int cifs_fileattr_get(struct dentry *dentry, struct file_kattr *fa) +{ + struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb); + struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb); + + /* + * Case sensitivity is reported based on the nocase mount option. + * CIFS servers typically perform case-insensitive lookups while + * preserving case in stored filenames. The nocase option indicates + * case-insensitive comparison is in effect for this mount. + */ + if (tcon->nocase) + fa->fsx_xflags |= FS_XFLAG_CASEFOLD; + return 0; +} + const struct inode_operations cifs_dir_inode_ops = { .create = cifs_create, .atomic_open = cifs_atomic_open,
@@ -1206,6 +1223,7 @@ const struct inode_operations cifs_dir_inode_ops = { .listxattr = cifs_listxattr, .get_acl = cifs_get_acl, .set_acl = cifs_set_acl, + .fileattr_get = cifs_fileattr_get, }; const struct inode_operations cifs_file_inode_ops = {
@@ -1216,6 +1234,7 @@ const struct inode_operations cifs_file_inode_ops = { .fiemap = cifs_fiemap, .get_acl = cifs_get_acl, .set_acl = cifs_set_acl, + .fileattr_get = cifs_fileattr_get, }; const char *cifs_get_link(struct dentry *dentry, struct inode *inode,
@@ -1250,6 +1269,7 @@ const struct inode_operations cifs_symlink_inode_ops = { .setattr = cifs_setattr, .permission = cifs_permission, .listxattr = cifs_listxattr, + .fileattr_get = cifs_fileattr_get, }; /*
--
2.53.0