Re: FreeBSD NFSv4.1 server exporting FreeBSD FAT filesystem - case-insensitive=true? Fwd: [PATCH v11 03/15] fat: Implement fileattr_get for case sensitivity

On Mon, Apr 27, 2026 at 12:13 AM Cedric Blancher
<[email protected]> wrote:
>
> Good morning!
>
> How does the FreeBSD NFSv4.1 server behave when it exports a FreeBSD
> FAT filesystem? Does it set the case-insensitive and
> case-nonpreserving FATTR4 attributes to case-insensitive=true?
It replies case-insensitive and case-preserving as both true.
(When I create a file called Readme, ls returns Readme, so I believe
that means case-preserving should be true.)

The file can be open'd with any combination of case: README, readme
or Readme, for example.

rick

>
> Ced
>
> ---------- Forwarded message ---------
> From: Chuck Lever <[email protected]>
> Date: Sat, 25 Apr 2026 at 03:53
> Subject: [PATCH v11 03/15] fat: Implement fileattr_get for case sensitivity
> To: Al Viro <[email protected]>, Christian Brauner
> <[email protected]>, Jan Kara <[email protected]>
> Cc: <[email protected]>, <[email protected]>,
> <[email protected]>, <[email protected]>,
> <[email protected]>, <[email protected]>,
> <[email protected]>,
> <[email protected]>, <[email protected]>,
> <[email protected]>, <[email protected]>,
> <[email protected]>, <[email protected]>,
> <[email protected]>, <[email protected]>, <[email protected]>,
> <[email protected]>, <[email protected]>, <[email protected]>,
> <[email protected]>, <[email protected]>,
> <[email protected]>, <[email protected]>, <[email protected]>,
> <[email protected]>, <[email protected]>, <[email protected]>,
> <[email protected]>, Chuck Lever <[email protected]>,
> Roland Mainz <[email protected]>
>
>
> From: Chuck Lever <[email protected]>
>
> Report FAT's case sensitivity behavior via the FS_XFLAG_CASEFOLD
> and FS_XFLAG_CASENONPRESERVING flags. FAT filesystems are
> case-insensitive by default.
>
> MSDOS supports a 'nocase' mount option that enables case-sensitive
> behavior; check this option when reporting case sensitivity.
>
> VFAT long filename entries preserve case; without VFAT, only
> uppercased 8.3 short names are stored. MSDOS with 'nocase' also
> preserves case since the name-formatting code skips upcasing when
> 'nocase' is set. Check both options when reporting case preservation.
>
> Reviewed-by: Jan Kara <[email protected]>
> Reviewed-by: Roland Mainz <[email protected]>
> Signed-off-by: Chuck Lever <[email protected]>
> ---
>  fs/fat/fat.h         |  3 +++
>  fs/fat/file.c        | 32 ++++++++++++++++++++++++++++++++
>  fs/fat/namei_msdos.c |  1 +
>  fs/fat/namei_vfat.c  |  1 +
>  4 files changed, 37 insertions(+)
>
> diff --git a/fs/fat/fat.h b/fs/fat/fat.h
> index 5a58f0bf8ce8..99ed9228a677 100644
> --- a/fs/fat/fat.h
> +++ b/fs/fat/fat.h
> @@ -10,6 +10,8 @@
>  #include <linux/fs_context.h>
>  #include <linux/fs_parser.h>
>
> +struct file_kattr;
> +
>  /*
>   * vfat shortname flags
>   */
> @@ -408,6 +410,7 @@ extern void fat_truncate_blocks(struct inode
> *inode, loff_t offset);
>  extern int fat_getattr(struct mnt_idmap *idmap,
>                        const struct path *path, struct kstat *stat,
>                        u32 request_mask, unsigned int flags);
> +int fat_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
>  extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
>                           int datasync);
>
> diff --git a/fs/fat/file.c b/fs/fat/file.c
> index becccdd2e501..5f0178fc2ede 100644
> --- a/fs/fat/file.c
> +++ b/fs/fat/file.c
> @@ -17,6 +17,7 @@
>  #include <linux/fsnotify.h>
>  #include <linux/security.h>
>  #include <linux/falloc.h>
> +#include <linux/fileattr.h>
>  #include "fat.h"
>
>  static long fat_fallocate(struct file *file, int mode,
> @@ -398,6 +399,36 @@ void fat_truncate_blocks(struct inode *inode,
> loff_t offset)
>         fat_flush_inodes(inode->i_sb, inode, NULL);
>  }
>
> +int fat_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
> +{
> +       struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
> +       bool case_sensitive;
> +
> +       /*
> +        * FAT filesystems are case-insensitive by default. VFAT
> +        * becomes case-sensitive when mounted with 'check=strict',
> +        * which installs vfat_dentry_ops. MSDOS has no such option;
> +        * its 'nocase' mount option selects case-sensitive matching.
> +        *
> +        * VFAT long filename entries preserve case. Without VFAT, only
> +        * uppercased 8.3 short names are stored. MSDOS with 'nocase'
> +        * also preserves case.
> +        */
> +       if (sbi->options.isvfat)
> +               case_sensitive = sbi->options.name_check == 's';
> +       else
> +               case_sensitive = sbi->options.nocase;
> +
> +       if (!case_sensitive) {
> +               fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
> +               fa->flags |= FS_CASEFOLD_FL;
> +               if (!sbi->options.isvfat)
> +                       fa->fsx_xflags |= FS_XFLAG_CASENONPRESERVING;
> +       }
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(fat_fileattr_get);
> +
>  int fat_getattr(struct mnt_idmap *idmap, const struct path *path,
>                 struct kstat *stat, u32 request_mask, unsigned int flags)
>  {
> @@ -575,5 +606,6 @@ EXPORT_SYMBOL_GPL(fat_setattr);
>  const struct inode_operations fat_file_inode_operations = {
>         .setattr        = fat_setattr,
>         .getattr        = fat_getattr,
> +       .fileattr_get   = fat_fileattr_get,
>         .update_time    = fat_update_time,
>  };
> diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
> index 4cc65f330fb7..0fd2971ad4b1 100644
> --- a/fs/fat/namei_msdos.c
> +++ b/fs/fat/namei_msdos.c
> @@ -644,6 +644,7 @@ static const struct inode_operations
> msdos_dir_inode_operations = {
>         .rename         = msdos_rename,
>         .setattr        = fat_setattr,
>         .getattr        = fat_getattr,
> +       .fileattr_get   = fat_fileattr_get,
>         .update_time    = fat_update_time,
>  };
>
> diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
> index 918b3756674c..e909447873e3 100644
> --- a/fs/fat/namei_vfat.c
> +++ b/fs/fat/namei_vfat.c
> @@ -1185,6 +1185,7 @@ static const struct inode_operations
> vfat_dir_inode_operations = {
>         .rename         = vfat_rename2,
>         .setattr        = fat_setattr,
>         .getattr        = fat_getattr,
> +       .fileattr_get   = fat_fileattr_get,
>         .update_time    = fat_update_time,
>  };
>
>
> --
> 2.53.0
>
>
>
>
> --
> Cedric Blancher <[email protected]>
> [https://plus.google.com/u/0/+CedricBlancher/]
> Institute Pasteur
>