afs: Concoct ctimes

The in-kernel afs filesystem ignores ctime because the AFS fileserver
protocol doesn't support ctimes.  This, however, causes various xfstests to
fail.

Work around this by:

 (1) Setting ctime to attr->ia_ctime in afs_setattr().

 (2) Not ignoring ATTR_MTIME_SET, ATTR_TIMES_SET and ATTR_TOUCH settings.

 (3) Setting the ctime from the server mtime when on the target file when
     creating a hard link to it.

 (4) Setting the ctime on directories from their revised mtimes when
     renaming/moving a file.

Found by the generic/221 and generic/309 xfstests.
Signed-off-by: David Howells <dhowells@redhat.com>

fs/afs/dir.c

@@ -1268,6 +1268,7 @@ static void afs_vnode_new_inode(struct afs_operation *op)
 static void afs_create_success(struct afs_operation *op)
 {
 	_enter("op=%08x", op->debug_id);
+	op->ctime = op->file[0].scb.status.mtime_client;
 	afs_check_for_remote_deletion(op, op->file[0].vnode);
 	afs_vnode_commit_status(op, &op->file[0]);
 	afs_update_dentry_version(op, &op->file[0], op->dentry);
@@ -1325,6 +1326,7 @@ static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 
 	afs_op_set_vnode(op, 0, dvnode);
 	op->file[0].dv_delta = 1;
+	op->file[0].update_ctime = true;
 	op->dentry	= dentry;
 	op->create.mode	= S_IFDIR | mode;
 	op->create.reason = afs_edit_dir_for_mkdir;
@@ -1350,6 +1352,7 @@ static void afs_dir_remove_subdir(struct dentry *dentry)
 static void afs_rmdir_success(struct afs_operation *op)
 {
 	_enter("op=%08x", op->debug_id);
+	op->ctime = op->file[0].scb.status.mtime_client;
 	afs_check_for_remote_deletion(op, op->file[0].vnode);
 	afs_vnode_commit_status(op, &op->file[0]);
 	afs_update_dentry_version(op, &op->file[0], op->dentry);
@@ -1404,6 +1407,7 @@ static int afs_rmdir(struct inode *dir, struct dentry *dentry)
 
 	afs_op_set_vnode(op, 0, dvnode);
 	op->file[0].dv_delta = 1;
+	op->file[0].update_ctime = true;
 
 	op->dentry	= dentry;
 	op->ops		= &afs_rmdir_operation;
@@ -1479,6 +1483,7 @@ static void afs_dir_remove_link(struct afs_operation *op)
 static void afs_unlink_success(struct afs_operation *op)
 {
 	_enter("op=%08x", op->debug_id);
+	op->ctime = op->file[0].scb.status.mtime_client;
 	afs_check_for_remote_deletion(op, op->file[0].vnode);
 	afs_vnode_commit_status(op, &op->file[0]);
 	afs_vnode_commit_status(op, &op->file[1]);
@@ -1537,6 +1542,7 @@ static int afs_unlink(struct inode *dir, struct dentry *dentry)
 
 	afs_op_set_vnode(op, 0, dvnode);
 	op->file[0].dv_delta = 1;
+	op->file[0].update_ctime = true;
 
 	/* Try to make sure we have a callback promise on the victim. */
 	ret = afs_validate(vnode, op->key);
@@ -1561,6 +1567,7 @@ static int afs_unlink(struct inode *dir, struct dentry *dentry)
 	spin_unlock(&dentry->d_lock);
 
 	op->file[1].vnode = vnode;
+	op->file[1].update_ctime = true;
 	op->dentry	= dentry;
 	op->ops		= &afs_unlink_operation;
 	return afs_do_sync_operation(op);
@@ -1601,6 +1608,7 @@ static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 
 	afs_op_set_vnode(op, 0, dvnode);
 	op->file[0].dv_delta = 1;
+	op->file[0].update_ctime = true;
 
 	op->dentry	= dentry;
 	op->create.mode	= S_IFREG | mode;
@@ -1620,6 +1628,7 @@ static void afs_link_success(struct afs_operation *op)
 	struct afs_vnode_param *vp = &op->file[1];
 
 	_enter("op=%08x", op->debug_id);
+	op->ctime = dvp->scb.status.mtime_client;
 	afs_vnode_commit_status(op, dvp);
 	afs_vnode_commit_status(op, vp);
 	afs_update_dentry_version(op, dvp, op->dentry);
@@ -1672,6 +1681,8 @@ static int afs_link(struct dentry *from, struct inode *dir,
 	afs_op_set_vnode(op, 0, dvnode);
 	afs_op_set_vnode(op, 1, vnode);
 	op->file[0].dv_delta = 1;
+	op->file[0].update_ctime = true;
+	op->file[1].update_ctime = true;
 
 	op->dentry		= dentry;
 	op->dentry_2		= from;
@@ -1740,9 +1751,12 @@ static void afs_rename_success(struct afs_operation *op)
 {
 	_enter("op=%08x", op->debug_id);
 
+	op->ctime = op->file[0].scb.status.mtime_client;
 	afs_vnode_commit_status(op, &op->file[0]);
-	if (op->file[1].vnode != op->file[0].vnode)
+	if (op->file[1].vnode != op->file[0].vnode) {
+		op->ctime = op->file[1].scb.status.mtime_client;
 		afs_vnode_commit_status(op, &op->file[1]);
+	}
 }
 
 static void afs_rename_edit_dir(struct afs_operation *op)
@@ -1860,6 +1874,8 @@ static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	afs_op_set_vnode(op, 1, new_dvnode); /* May be same as orig_dvnode */
 	op->file[0].dv_delta = 1;
 	op->file[1].dv_delta = 1;
+	op->file[0].update_ctime = true;
+	op->file[1].update_ctime = true;
 
 	op->dentry		= old_dentry;
 	op->dentry_2		= new_dentry;

fs/afs/inode.c

@@ -165,6 +165,7 @@ static void afs_apply_status(struct afs_operation *op,
 {
 	struct afs_file_status *status = &vp->scb.status;
 	struct afs_vnode *vnode = vp->vnode;
+	struct inode *inode = &vnode->vfs_inode;
 	struct timespec64 t;
 	umode_t mode;
 	bool data_changed = false;
@@ -187,25 +188,25 @@ static void afs_apply_status(struct afs_operation *op,
 	}
 
 	if (status->nlink != vnode->status.nlink)
-		set_nlink(&vnode->vfs_inode, status->nlink);
+		set_nlink(inode, status->nlink);
 
 	if (status->owner != vnode->status.owner)
-		vnode->vfs_inode.i_uid = make_kuid(&init_user_ns, status->owner);
+		inode->i_uid = make_kuid(&init_user_ns, status->owner);
 
 	if (status->group != vnode->status.group)
-		vnode->vfs_inode.i_gid = make_kgid(&init_user_ns, status->group);
+		inode->i_gid = make_kgid(&init_user_ns, status->group);
 
 	if (status->mode != vnode->status.mode) {
-		mode = vnode->vfs_inode.i_mode;
+		mode = inode->i_mode;
 		mode &= ~S_IALLUGO;
 		mode |= status->mode;
-		WRITE_ONCE(vnode->vfs_inode.i_mode, mode);
+		WRITE_ONCE(inode->i_mode, mode);
 	}
 
 	t = status->mtime_client;
-	vnode->vfs_inode.i_ctime = t;
-	vnode->vfs_inode.i_mtime = t;
-	vnode->vfs_inode.i_atime = t;
+	inode->i_mtime = t;
+	if (vp->update_ctime)
+		inode->i_ctime = op->ctime;
 
 	if (vnode->status.data_version != status->data_version)
 		data_changed = true;
@@ -239,15 +240,18 @@ static void afs_apply_status(struct afs_operation *op,
 	}
 
 	if (data_changed) {
-		inode_set_iversion_raw(&vnode->vfs_inode, status->data_version);
+		inode_set_iversion_raw(inode, status->data_version);
 
 		/* Only update the size if the data version jumped.  If the
 		 * file is being modified locally, then we might have our own
 		 * idea of what the size should be that's not the same as
 		 * what's on the server.
 		 */
-		if (change_size)
+		if (change_size) {
 			afs_set_i_size(vnode, status->size);
+			inode->i_ctime = t;
+			inode->i_atime = t;
+		}
 	}
 }
 
@@ -817,7 +821,8 @@ int afs_setattr(struct dentry *dentry, struct iattr *attr)
 	       attr->ia_valid);
 
 	if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
-				ATTR_MTIME))) {
+				ATTR_MTIME | ATTR_MTIME_SET | ATTR_TIMES_SET |
+				ATTR_TOUCH))) {
 		_leave(" = 0 [unsupported]");
 		return 0;
 	}
@@ -837,6 +842,8 @@ int afs_setattr(struct dentry *dentry, struct iattr *attr)
 
 	if (attr->ia_valid & ATTR_SIZE)
 		op->file[0].dv_delta = 1;
+	op->ctime = attr->ia_ctime;
+	op->file[0].update_ctime = 1;
 
 	op->ops = &afs_setattr_operation;
 	return afs_do_sync_operation(op);

fs/afs/internal.h

@@ -746,6 +746,7 @@ struct afs_vnode_param {
 	u8			dv_delta;	/* Expected change in data version */
 	bool			put_vnode;	/* T if we have a ref on the vnode */
 	bool			need_io_lock;	/* T if we need the I/O lock on this */
+	bool			update_ctime;	/* Need to update the ctime */
 };
 
 /*
@@ -766,6 +767,7 @@ struct afs_operation {
 	struct dentry		*dentry;	/* Dentry to be altered */
 	struct dentry		*dentry_2;	/* Second dentry to be altered */
 	struct timespec64	mtime;		/* Modification time to record */
+	struct timespec64	ctime;		/* Change time to set */
 	short			nr_files;	/* Number of entries in file[], more_files */
 	short			error;
 	unsigned int		abort_code;

fs/afs/write.c

@@ -393,6 +393,7 @@ static void afs_store_data_success(struct afs_operation *op)
 {
 	struct afs_vnode *vnode = op->file[0].vnode;
 
+	op->ctime = op->file[0].scb.status.mtime_client;
 	afs_vnode_commit_status(op, &op->file[0]);
 	if (op->error == 0) {
 		afs_pages_written_back(vnode, op->store.first, op->store.last);