Revert "lockd: introduce safe async lock op"

This reverts commit 2267b2e845.

ltp test fcntl17 fails on v5.15.154. This was bisected to commit
2267b2e845 ("lockd: introduce safe async lock op").

Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/filesystems/nfs/exporting.rst

@@ -241,10 +241,3 @@ following flags are defined:
     all of an inode's dirty data on last close. Exports that behave this
     way should set EXPORT_OP_FLUSH_ON_CLOSE so that NFSD knows to skip
     waiting for writeback when closing such files.
-
-  EXPORT_OP_ASYNC_LOCK - Indicates a capable filesystem to do async lock
-    requests from lockd. Only set EXPORT_OP_ASYNC_LOCK if the filesystem has
-    it's own ->lock() functionality as core posix_lock_file() implementation
-    has no async lock request handling yet. For more information about how to
-    indicate an async lock request from a ->lock() file_operations struct, see
-    fs/locks.c and comment for the function vfs_lock_file().

fs/lockd/svclock.c

@@ -470,7 +470,9 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 	    struct nlm_host *host, struct nlm_lock *lock, int wait,
 	    struct nlm_cookie *cookie, int reclaim)
 {
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 	struct inode		*inode = nlmsvc_file_inode(file);
+#endif
 	struct nlm_block	*block = NULL;
 	int			error;
 	int			mode;
@@ -484,7 +486,7 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
 				(long long)lock->fl.fl_end,
 				wait);
 
-	if (!exportfs_lock_op_is_async(inode->i_sb->s_export_op)) {
+	if (nlmsvc_file_file(file)->f_op->lock) {
 		async_block = wait;
 		wait = 0;
 	}

fs/nfsd/nfs4state.c

@@ -7420,7 +7420,6 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	struct nfsd4_blocked_lock *nbl = NULL;
 	struct file_lock *file_lock = NULL;
 	struct file_lock *conflock = NULL;
-	struct super_block *sb;
 	__be32 status = 0;
 	int lkflg;
 	int err;
@@ -7442,7 +7441,6 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		dprintk("NFSD: nfsd4_lock: permission denied!\n");
 		return status;
 	}
-	sb = cstate->current_fh.fh_dentry->d_sb;
 
 	if (lock->lk_is_new) {
 		if (nfsd4_has_session(cstate))
@@ -7494,8 +7492,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	fp = lock_stp->st_stid.sc_file;
 	switch (lock->lk_type) {
 		case NFS4_READW_LT:
-			if (nfsd4_has_session(cstate) ||
-			    exportfs_lock_op_is_async(sb->s_export_op))
+			if (nfsd4_has_session(cstate))
 				fl_flags |= FL_SLEEP;
 			fallthrough;
 		case NFS4_READ_LT:
@@ -7507,8 +7504,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 			fl_type = F_RDLCK;
 			break;
 		case NFS4_WRITEW_LT:
-			if (nfsd4_has_session(cstate) ||
-			    exportfs_lock_op_is_async(sb->s_export_op))
+			if (nfsd4_has_session(cstate))
 				fl_flags |= FL_SLEEP;
 			fallthrough;
 		case NFS4_WRITE_LT:
@@ -7536,7 +7532,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	 * for file locks), so don't attempt blocking lock notifications
 	 * on those filesystems:
 	 */
-	if (!exportfs_lock_op_is_async(sb->s_export_op))
+	if (nf->nf_file->f_op->lock)
 		fl_flags &= ~FL_SLEEP;
 
 	nbl = find_or_allocate_block(lock_sop, &fp->fi_fhandle, nn);

include/linux/exportfs.h

@@ -222,23 +222,9 @@ struct export_operations {
 						  atomic attribute updates
 						*/
 #define EXPORT_OP_FLUSH_ON_CLOSE	(0x20) /* fs flushes file data on close */
-#define EXPORT_OP_ASYNC_LOCK		(0x40) /* fs can do async lock request */
 	unsigned long	flags;
 };
 
-/**
- * exportfs_lock_op_is_async() - export op supports async lock operation
- * @export_ops:	the nfs export operations to check
- *
- * Returns true if the nfs export_operations structure has
- * EXPORT_OP_ASYNC_LOCK in their flags set
- */
-static inline bool
-exportfs_lock_op_is_async(const struct export_operations *export_ops)
-{
-	return export_ops->flags & EXPORT_OP_ASYNC_LOCK;
-}
-
 extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,
 				    int *max_len, struct inode *parent);
 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,