NFSD: use (un)lock_inode instead of fh_(un)lock for file operations

When locking a file to access ACLs and xattrs etc, use explicit locking
with inode_lock() instead of fh_lock().  This means that the calls to
fh_fill_pre/post_attr() are also explicit which improves readability and
allows us to place them only where they are needed.  Only the xattr
calls need pre/post information.

When locking a file we don't need I_MUTEX_PARENT as the file is not a
parent of anything, so we can use inode_lock() directly rather than the
inode_lock_nested() call that fh_lock() uses.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

1 files changed, 20 insertions, 14 deletions

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 19b47ca2f238..8d5aa2faabf7 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -416,7 +416,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp,
 			return err;
 	}
 
-	fh_lock(fhp);
+	inode_lock(inode);
 	if (size_change) {
 		/*
 		 * RFC5661, Section 18.30.4:
@@ -464,7 +464,7 @@ out_unlock:
 		attr->na_aclerr = set_posix_acl(&init_user_ns,
 						inode, ACL_TYPE_DEFAULT,
 						attr->na_dpacl);
-	fh_unlock(fhp);
+	inode_unlock(inode);
 	if (size_change)
 		put_write_access(inode);
 out:
@@ -2155,13 +2155,16 @@ out:
 	return err;
 }
 
-/*
- * Removexattr and setxattr need to call fh_lock to both lock the inode
- * and set the change attribute. Since the top-level vfs_removexattr
- * and vfs_setxattr calls already do their own inode_lock calls, call
- * the _locked variant. Pass in a NULL pointer for delegated_inode,
- * and let the client deal with NFS4ERR_DELAY (same as with e.g.
- * setattr and remove).
+/**
+ * nfsd_removexattr - Remove an extended attribute
+ * @rqstp: RPC transaction being executed
+ * @fhp: NFS filehandle of object with xattr to remove
+ * @name: name of xattr to remove (NUL-terminate)
+ *
+ * Pass in a NULL pointer for delegated_inode, and let the client deal
+ * with NFS4ERR_DELAY (same as with e.g. setattr and remove).
+ *
+ * Returns nfs_ok on success, or an nfsstat in network byte order.
  */
 __be32
 nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
@@ -2177,12 +2180,14 @@ nfsd_removexattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name)
 	if (ret)
 		return nfserrno(ret);
 
-	fh_lock(fhp);
+	inode_lock(fhp->fh_dentry->d_inode);
+	fh_fill_pre_attrs(fhp);
 
 	ret = __vfs_removexattr_locked(&init_user_ns, fhp->fh_dentry,
 				       name, NULL);
 
-	fh_unlock(fhp);
+	fh_fill_post_attrs(fhp);
+	inode_unlock(fhp->fh_dentry->d_inode);
 	fh_drop_write(fhp);
 
 	return nfsd_xattr_errno(ret);
@@ -2202,12 +2207,13 @@ nfsd_setxattr(struct svc_rqst *rqstp, struct svc_fh *fhp, char *name,
 	ret = fh_want_write(fhp);
 	if (ret)
 		return nfserrno(ret);
-	fh_lock(fhp);
+	inode_lock(fhp->fh_dentry->d_inode);
+	fh_fill_pre_attrs(fhp);
 
 	ret = __vfs_setxattr_locked(&init_user_ns, fhp->fh_dentry, name, buf,
 				    len, flags, NULL);
-
-	fh_unlock(fhp);
+	fh_fill_post_attrs(fhp);
+	inode_unlock(fhp->fh_dentry->d_inode);
 	fh_drop_write(fhp);
 
 	return nfsd_xattr_errno(ret);