6.15-stable review patch. If anyone has any objections, please let me know.
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From: Amir Goldstein amir73il@gmail.com
[ Upstream commit 5402c4d4d2000a9baa30c1157c97152ec6383733 ]
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@gmail.com Link: https://lore.kernel.org/20250525104731.1461704-1-amir73il@gmail.com Reviewed-by: Jan Kara jack@suse.cz Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/exportfs.h | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h index fc93f0abf513c..25c4a5afbd443 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.