VFS: change vfs_mkdir() to unlock on failure.

vfs_mkdir() already drops the reference to the dentry on failure but it
leaves the parent locked.
This complicates end_creating() which needs to unlock the parent even
though the dentry is no longer available.

If we change vfs_mkdir() to unlock on failure as well as releasing the
dentry, we can remove the "parent" arg from end_creating() and simplify
the rules for calling it.

Note that cachefiles_get_directory() can choose to substitute an error
instead of actually calling vfs_mkdir(), for fault injection.  In that
case it needs to call end_creating(), just as vfs_mkdir() now does on
error.

ovl_create_real() will now unlock on error.  So the conditional
end_creating() after the call is removed, and end_creating() is called
internally on error.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: syzbot@syzkaller.appspotmail.com
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20251113002050.676694-15-neilb@ownmail.net
Signed-off-by: Christian Brauner <brauner@kernel.org>

5 files changed, 8 insertions, 8 deletions

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index e2aac0def2cb..6b39e4aff959 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -364,7 +364,7 @@ set_attr:
 	status = nfsd_create_setattr(rqstp, fhp, resfhp, &attrs);
 
 out:
-	end_creating(child, parent);
+	end_creating(child);
 out_write:
 	fh_drop_write(fhp);
 	return status;
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index b2c95e8e7c68..524cb07a477c 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -376,7 +376,7 @@ set_attr:
 	if (attrs.na_aclerr)
 		open->op_bmval[0] &= ~FATTR4_WORD0_ACL;
 out:
-	end_creating(child, parent);
+	end_creating(child);
 	nfsd_attrs_free(&attrs);
 out_write:
 	fh_drop_write(fhp);
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 3eefaa2202e3..18c08395b273 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -215,7 +215,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp)
 	if (IS_ERR(dentry))
 		status = PTR_ERR(dentry);
 out_end:
-	end_creating(dentry, dir);
+	end_creating(dentry);
 out:
 	if (status == 0) {
 		if (nn->in_grace)
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index ee1b16e921fd..28f03a6a3cc3 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -421,7 +421,7 @@ nfsd_proc_create(struct svc_rqst *rqstp)
 	}
 
 out_unlock:
-	end_creating(dchild, dirfhp->fh_dentry);
+	end_creating(dchild);
 out_write:
 	fh_drop_write(dirfhp);
 done:
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 62109885d4db..6e9a57863904 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1589,7 +1589,7 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
 out:
 	if (!err)
 		fh_fill_post_attrs(fhp);
-	end_creating(dchild, dentry);
+	end_creating(dchild);
 	return err;
 
 out_nfserr:
@@ -1646,7 +1646,7 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	return err;
 
 out_unlock:
-	end_creating(dchild, dentry);
+	end_creating(dchild);
 	return err;
 }
 
@@ -1747,7 +1747,7 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		nfsd_create_setattr(rqstp, fhp, resfhp, attrs);
 	fh_fill_post_attrs(fhp);
 out_unlock:
-	end_creating(dnew, dentry);
+	end_creating(dnew);
 	if (!err)
 		err = nfserrno(commit_metadata(fhp));
 	if (!err)
@@ -1824,7 +1824,7 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
 	host_err = vfs_link(dold, &nop_mnt_idmap, dirp, dnew, NULL);
 	fh_fill_post_attrs(ffhp);
 out_unlock:
-	end_creating(dnew, ddir);
+	end_creating(dnew);
 	if (!host_err) {
 		host_err = commit_metadata(ffhp);
 		if (!host_err)