NFSD: Revert 6c41d9a9bd0298002805758216a9c44e38a8500d

For some reason, the wait_on_bit() in nfsd4_deleg_getattr_conflict()
is waiting forever, preventing a clean server shutdown. The
requesting client might also hang waiting for a reply to the
conflicting GETATTR.

Invoking wait_on_bit() in an nfsd thread context is a hazard. The
correct fix is to replace this wait_on_bit() call site with a
mechanism that defers the conflicting GETATTR until the CB_GETATTR
completes or is known to have failed.

That will require some surgery and extended testing and it's late
in the v6.7-rc cycle, so I'm reverting now in favor of trying again
in a subsequent kernel release.

This is my fault: I should have recognized the ramifications of
calling wait_on_bit() in here before accepting this patch.

Thanks to Dai Ngo <dai.ngo@oracle.com> for diagnosing the issue.

Reported-by: Wolfgang Walter <linux-nfs@stwm.de>
Closes: https://lore.kernel.org/linux-nfs/e3d43ecdad554fbdcaa7181833834f78@stwm.de/
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

1 files changed, 1 insertions, 10 deletions

diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index f96eaa8e9413..0bbbe57e027d 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -125,16 +125,8 @@ struct nfs4_cb_fattr {
 	/* from CB_GETATTR reply */
 	u64 ncf_cb_change;
 	u64 ncf_cb_fsize;
-
-	unsigned long ncf_cb_flags;
-	bool ncf_file_modified;
-	u64 ncf_initial_cinfo;
-	u64 ncf_cur_fsize;
 };
 
-/* bits for ncf_cb_flags */
-#define	CB_GETATTR_BUSY		0
-
 /*
  * Represents a delegation stateid. The nfs4_client holds references to these
  * and they are put when it is being destroyed or when the delegation is
@@ -754,6 +746,5 @@ static inline bool try_to_expire_client(struct nfs4_client *clp)
 }
 
 extern __be32 nfsd4_deleg_getattr_conflict(struct svc_rqst *rqstp,
-		struct inode *inode, bool *file_modified, u64 *size);
-extern void nfs4_cb_getattr(struct nfs4_cb_fattr *ncf);
+				struct inode *inode);
 #endif   /* NFSD4_STATE_H */