When user requests a connectable file handle explicitly with the
AT_HANDLE_CONNECTABLE flag, fail the request if filesystem (e.g. nfs)
does not know how to decode a connected non-dir dentry.
Fixes: c374196b2b9f ("fs: name_to_handle_at() support for "explicit connectable" file handles")
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
include/linux/exportfs.h | 10 ++++++++++
1 file changed, 10 insertions(+)
Christian,
This fixes fstest failures with nfs client (re-export)
reported by Zoro [1].
Thanks,
Amir.
[1] https://lore.kernel.org/fstests/20250525053604.k466kgfcumw2s2qx@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index fc93f0abf513..25c4a5afbd44 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -314,6 +314,9 @@ static inline bool exportfs_can_decode_fh(const struct export_operations *nop)
static inline bool exportfs_can_encode_fh(const struct export_operations *nop,
int fh_flags)
{
+ if (!nop)
+ return false;
+
/*
* If a non-decodeable file handle was requested, we only need to make
* sure that filesystem did not opt-out of encoding fid.
@@ -321,6 +324,13 @@ static inline bool exportfs_can_encode_fh(const struct export_operations *nop,
if (fh_flags & EXPORT_FH_FID)
return exportfs_can_encode_fid(nop);
+ /*
+ * If a connectable file handle was requested, we need to make sure that
+ * filesystem can also decode connected file handles.
+ */
+ if ((fh_flags & EXPORT_FH_CONNECTABLE) && !nop->fh_to_parent)
+ return false;
+
/*
* If a decodeable file handle was requested, we need to make sure that
* filesystem can also decode file handles.
--
2.34.1
