On Wed, 2023-10-18 at 12:59 +0300, Amir Goldstein wrote:
> The logic of whether filesystem can encode/decode file handles is open
> coded in many places.
>
> In preparation to changing the logic, move the open coded logic into
> inline helpers.
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/exportfs/expfs.c | 8 ++------
> fs/fhandle.c | 6 +-----
> fs/nfsd/export.c | 3 +--
> fs/notify/fanotify/fanotify_user.c | 4 ++--
> fs/overlayfs/util.c | 2 +-
> include/linux/exportfs.h | 27 +++++++++++++++++++++++++++
> 6 files changed, 34 insertions(+), 16 deletions(-)
>
> diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
> index c20704aa21b3..9ee205df8fa7 100644
> --- a/fs/exportfs/expfs.c
> +++ b/fs/exportfs/expfs.c
> @@ -396,11 +396,7 @@ int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
> {
> const struct export_operations *nop = inode->i_sb->s_export_op;
>
> - /*
> - * If a decodeable file handle was requested, we need to make sure that
> - * filesystem can decode file handles.
> - */
> - if (nop && !(flags & EXPORT_FH_FID) && !nop->fh_to_dentry)
> + if (!exportfs_can_encode_fh(nop, flags))
> return -EOPNOTSUPP;
>
> if (nop && nop->encode_fh)
> @@ -456,7 +452,7 @@ exportfs_decode_fh_raw(struct vfsmount *mnt, struct fid *fid, int fh_len,
> /*
> * Try to get any dentry for the given file handle from the filesystem.
> */
> - if (!nop || !nop->fh_to_dentry)
> + if (!exportfs_can_decode_fh(nop))
> return ERR_PTR(-ESTALE);
> result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type);
> if (IS_ERR_OR_NULL(result))
> diff --git a/fs/fhandle.c b/fs/fhandle.c
> index 6ea8d35a9382..18b3ba8dc8ea 100644
> --- a/fs/fhandle.c
> +++ b/fs/fhandle.c
> @@ -26,12 +26,8 @@ static long do_sys_name_to_handle(const struct path *path,
> /*
> * We need to make sure whether the file system support decoding of
> * the file handle if decodeable file handle was requested.
> - * Otherwise, even empty export_operations are sufficient to opt-in
> - * to encoding FIDs.
> */
> - if (!path->dentry->d_sb->s_export_op ||
> - (!(fh_flags & EXPORT_FH_FID) &&
> - !path->dentry->d_sb->s_export_op->fh_to_dentry))
> + if (!exportfs_can_encode_fh(path->dentry->d_sb->s_export_op, fh_flags))
> return -EOPNOTSUPP;
>
> if (copy_from_user(&f_handle, ufh, sizeof(struct file_handle)))
> diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
> index 11a0eaa2f914..dc99dfc1d411 100644
> --- a/fs/nfsd/export.c
> +++ b/fs/nfsd/export.c
> @@ -421,8 +421,7 @@ static int check_export(struct path *path, int *flags, unsigned char *uuid)
> return -EINVAL;
> }
>
> - if (!inode->i_sb->s_export_op ||
> - !inode->i_sb->s_export_op->fh_to_dentry) {
> + if (!exportfs_can_decode_fh(inode->i_sb->s_export_op)) {
> dprintk("exp_export: export of invalid fs type.\n");
> return -EINVAL;
> }
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 537c70beaad0..ce926eb9feea 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -1595,7 +1595,7 @@ static int fanotify_test_fid(struct dentry *dentry, unsigned int flags)
> * file handles so user can use name_to_handle_at() to compare fids
> * reported with events to the file handle of watched objects.
> */
> - if (!nop)
> + if (!exportfs_can_encode_fid(nop))
> return -EOPNOTSUPP;
>
> /*
> @@ -1603,7 +1603,7 @@ static int fanotify_test_fid(struct dentry *dentry, unsigned int flags)
> * supports decoding file handles, so user has a way to map back the
> * reported fids to filesystem objects.
> */
> - if (mark_type != FAN_MARK_INODE && !nop->fh_to_dentry)
> + if (mark_type != FAN_MARK_INODE && !exportfs_can_decode_fh(nop))
> return -EOPNOTSUPP;
>
> return 0;
> diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
> index 89e0d60d35b6..f0a712214ec2 100644
> --- a/fs/overlayfs/util.c
> +++ b/fs/overlayfs/util.c
> @@ -55,7 +55,7 @@ int ovl_can_decode_fh(struct super_block *sb)
> if (!capable(CAP_DAC_READ_SEARCH))
> return 0;
>
> - if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry)
> + if (!exportfs_can_decode_fh(sb->s_export_op))
> return 0;
>
> return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN;
> diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
> index 11fbd0ee1370..5b3c9f30b422 100644
> --- a/include/linux/exportfs.h
> +++ b/include/linux/exportfs.h
> @@ -233,6 +233,33 @@ extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
> extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
> int *max_len, int flags);
>
> +static inline bool exportfs_can_encode_fid(const struct export_operations *nop)
> +{
> + return nop;
> +}
> +
> +static inline bool exportfs_can_decode_fh(const struct export_operations *nop)
> +{
> + return nop && nop->fh_to_dentry;
> +}
> +
> +static inline bool exportfs_can_encode_fh(const struct export_operations *nop,
> + int fh_flags)
> +{
> + /*
> + * If a non-decodeable file handle was requested, we only need to make
> + * sure that filesystem can encode file handles.
> + */
> + if (fh_flags & EXPORT_FH_FID)
> + return exportfs_can_encode_fid(nop);
> +
> + /*
> + * If a decodeable file handle was requested, we need to make sure that
> + * filesystem can also decode file handles.
> + */
> + return exportfs_can_decode_fh(nop);
> +}
> +
> static inline int exportfs_encode_fid(struct inode *inode, struct fid *fid,
> int *max_len)
> {
Nice cleanup.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
