Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 853 insertions, 0 deletions

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
new file mode 100644
index 000000000..14f39a9be
--- /dev/null
+++ b/fs/afs/inode.c
@@ -0,0 +1,853 @@
+/*
+ * Copyright (c) 2002 Red Hat, Inc. All rights reserved.
+ *
+ * This software may be freely redistributed under the terms of the
+ * GNU General Public License.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Authors: David Woodhouse <dwmw2@infradead.org>
+ *          David Howells <dhowells@redhat.com>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/sched.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/iversion.h>
+#include "internal.h"
+#include "afs_fs.h"
+
+static noinline void dump_vnode(struct afs_vnode *vnode, struct afs_vnode *parent_vnode)
+{
+	static unsigned long once_only;
+
+	pr_warn("kAFS: AFS vnode with undefined type %u\n", vnode->status.type);
+	pr_warn("kAFS: A=%d m=%o s=%llx v=%llx\n",
+		vnode->status.abort_code,
+		vnode->status.mode,
+		vnode->status.size,
+		vnode->status.data_version);
+	pr_warn("kAFS: vnode %llx:%llx:%x\n",
+		vnode->fid.vid,
+		vnode->fid.vnode,
+		vnode->fid.unique);
+	if (parent_vnode)
+		pr_warn("kAFS: dir %llx:%llx:%x\n",
+			parent_vnode->fid.vid,
+			parent_vnode->fid.vnode,
+			parent_vnode->fid.unique);
+
+	if (!test_and_set_bit(0, &once_only))
+		dump_stack();
+}
+
+/*
+ * Set parameters for the netfs library
+ */
+static void afs_set_netfs_context(struct afs_vnode *vnode, bool is_file)
+{
+	netfs_inode_init(&vnode->netfs, &afs_req_ops, is_file);
+}
+
+/*
+ * Initialise an inode from the vnode status.
+ */
+static int afs_inode_init_from_status(struct afs_operation *op,
+				      struct afs_vnode_param *vp,
+				      struct afs_vnode *vnode)
+{
+	struct afs_file_status *status = &vp->scb.status;
+	struct inode *inode = AFS_VNODE_TO_I(vnode);
+	struct timespec64 t;
+
+	_enter("{%llx:%llu.%u} %s",
+	       vp->fid.vid, vp->fid.vnode, vp->fid.unique,
+	       op->type ? op->type->name : "???");
+
+	_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
+	       status->type,
+	       status->nlink,
+	       (unsigned long long) status->size,
+	       status->data_version,
+	       status->mode);
+
+	write_seqlock(&vnode->cb_lock);
+
+	vnode->cb_v_check = op->cb_v_break;
+	vnode->status = *status;
+
+	t = status->mtime_client;
+	inode_set_ctime_to_ts(inode, t);
+	inode_set_mtime_to_ts(inode, t);
+	inode_set_atime_to_ts(inode, t);
+	inode->i_flags |= S_NOATIME;
+	inode->i_uid = make_kuid(&init_user_ns, status->owner);
+	inode->i_gid = make_kgid(&init_user_ns, status->group);
+	set_nlink(&vnode->netfs.inode, status->nlink);
+
+	i_size_write(inode, status->size);
+	inode_set_bytes(inode, status->size);
+	afs_set_netfs_context(vnode, status->type == AFS_FTYPE_FILE);
+
+	switch (status->type) {
+	case AFS_FTYPE_FILE:
+		inode->i_mode	= S_IFREG | (status->mode & S_IALLUGO);
+		inode->i_op	= &afs_file_inode_operations;
+		inode->i_fop	= &afs_file_operations;
+		inode->i_mapping->a_ops	= &afs_file_aops;
+		mapping_set_large_folios(inode->i_mapping);
+		break;
+	case AFS_FTYPE_DIR:
+		inode->i_mode	= S_IFDIR |  (status->mode & S_IALLUGO);
+		inode->i_op	= &afs_dir_inode_operations;
+		inode->i_fop	= &afs_dir_file_operations;
+		inode->i_mapping->a_ops	= &afs_dir_aops;
+		__set_bit(NETFS_ICTX_SINGLE_NO_UPLOAD, &vnode->netfs.flags);
+		/* Assume locally cached directory data will be valid. */
+		__set_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+		break;
+	case AFS_FTYPE_SYMLINK:
+		/* Symlinks with a mode of 0644 are actually mountpoints. */
+		if ((status->mode & 0777) == 0644) {
+			inode->i_flags |= S_AUTOMOUNT;
+
+			set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
+
+			inode->i_mode	= S_IFDIR | 0555;
+			inode->i_op	= &afs_mntpt_inode_operations;
+			inode->i_fop	= &afs_mntpt_file_operations;
+		} else {
+			inode->i_mode	= S_IFLNK | status->mode;
+			inode->i_op	= &afs_symlink_inode_operations;
+		}
+		inode->i_mapping->a_ops	= &afs_symlink_aops;
+		inode_nohighmem(inode);
+		break;
+	default:
+		dump_vnode(vnode, op->file[0].vnode != vnode ? op->file[0].vnode : NULL);
+		write_sequnlock(&vnode->cb_lock);
+		return afs_protocol_error(NULL, afs_eproto_file_type);
+	}
+
+	vnode->invalid_before	= status->data_version;
+	trace_afs_set_dv(vnode, status->data_version);
+	inode_set_iversion_raw(&vnode->netfs.inode, status->data_version);
+
+	if (!vp->scb.have_cb) {
+		/* it's a symlink we just created (the fileserver
+		 * didn't give us a callback) */
+		afs_clear_cb_promise(vnode, afs_cb_promise_set_new_symlink);
+	} else {
+		vnode->cb_server = op->server;
+		afs_set_cb_promise(vnode, vp->scb.callback.expires_at,
+				   afs_cb_promise_set_new_inode);
+	}
+
+	write_sequnlock(&vnode->cb_lock);
+	return 0;
+}
+
+/*
+ * Update the core inode struct from a returned status record.
+ */
+static void afs_apply_status(struct afs_operation *op,
+			     struct afs_vnode_param *vp)
+{
+	struct afs_file_status *status = &vp->scb.status;
+	struct afs_vnode *vnode = vp->vnode;
+	struct netfs_inode *ictx = &vnode->netfs;
+	struct inode *inode = &ictx->inode;
+	struct timespec64 t;
+	umode_t mode;
+	bool unexpected_jump = false;
+	bool data_changed = false;
+	bool change_size = vp->set_size;
+
+	_enter("{%llx:%llu.%u} %s",
+	       vp->fid.vid, vp->fid.vnode, vp->fid.unique,
+	       op->type ? op->type->name : "???");
+
+	BUG_ON(test_bit(AFS_VNODE_UNSET, &vnode->flags));
+
+	if (status->type != vnode->status.type) {
+		pr_warn("Vnode %llx:%llx:%x changed type %u to %u\n",
+			vnode->fid.vid,
+			vnode->fid.vnode,
+			vnode->fid.unique,
+			status->type, vnode->status.type);
+		afs_protocol_error(NULL, afs_eproto_bad_status);
+		return;
+	}
+
+	if (status->nlink != vnode->status.nlink)
+		set_nlink(inode, status->nlink);
+
+	if (status->owner != vnode->status.owner)
+		inode->i_uid = make_kuid(&init_user_ns, status->owner);
+
+	if (status->group != vnode->status.group)
+		inode->i_gid = make_kgid(&init_user_ns, status->group);
+
+	if (status->mode != vnode->status.mode) {
+		mode = inode->i_mode;
+		mode &= ~S_IALLUGO;
+		mode |= status->mode & S_IALLUGO;
+		WRITE_ONCE(inode->i_mode, mode);
+	}
+
+	t = status->mtime_client;
+	inode_set_mtime_to_ts(inode, t);
+	if (vp->update_ctime)
+		inode_set_ctime_to_ts(inode, op->ctime);
+
+	if (vnode->status.data_version != status->data_version) {
+		trace_afs_set_dv(vnode, status->data_version);
+		data_changed = true;
+	}
+
+	vnode->status = *status;
+
+	if (vp->dv_before + vp->dv_delta != status->data_version) {
+		trace_afs_dv_mismatch(vnode, vp->dv_before, vp->dv_delta,
+				      status->data_version);
+
+		if (vnode->cb_ro_snapshot == atomic_read(&vnode->volume->cb_ro_snapshot) &&
+		    atomic64_read(&vnode->cb_expires_at) != AFS_NO_CB_PROMISE)
+			pr_warn("kAFS: vnode modified {%llx:%llu} %llx->%llx %s (op=%x)\n",
+				vnode->fid.vid, vnode->fid.vnode,
+				(unsigned long long)vp->dv_before + vp->dv_delta,
+				(unsigned long long)status->data_version,
+				op->type ? op->type->name : "???",
+				op->debug_id);
+
+		vnode->invalid_before = status->data_version;
+		if (vnode->status.type == AFS_FTYPE_DIR)
+			afs_invalidate_dir(vnode, afs_dir_invalid_dv_mismatch);
+		else
+			set_bit(AFS_VNODE_ZAP_DATA, &vnode->flags);
+		change_size = true;
+		data_changed = true;
+		unexpected_jump = true;
+	} else if (vnode->status.type == AFS_FTYPE_DIR) {
+		/* Expected directory change is handled elsewhere so
+		 * that we can locally edit the directory and save on a
+		 * download.
+		 */
+		if (test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
+			data_changed = false;
+		change_size = true;
+	}
+
+	if (data_changed) {
+		unsigned long long zero_point, size = status->size;
+
+		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.
+		 */
+		spin_lock(&inode->i_lock);
+
+		if (change_size || size > i_size_read(inode)) {
+			/* We can read the sizes directly as we hold i_lock. */
+			zero_point = ictx->_zero_point;
+
+			if (unexpected_jump)
+				zero_point = size;
+			netfs_write_sizes(inode, size, size, zero_point);
+			inode_set_bytes(inode, size);
+			inode_set_ctime_to_ts(inode, t);
+			inode_set_atime_to_ts(inode, t);
+		} else {
+			netfs_write_remote_i_size(inode, size);
+		}
+		spin_unlock(&inode->i_lock);
+
+		if (op->ops == &afs_fetch_data_operation)
+			op->fetch.subreq->rreq->i_size = size;
+	}
+}
+
+/*
+ * Apply a callback to a vnode.
+ */
+static void afs_apply_callback(struct afs_operation *op,
+			       struct afs_vnode_param *vp)
+{
+	struct afs_callback *cb = &vp->scb.callback;
+	struct afs_vnode *vnode = vp->vnode;
+
+	if (!afs_cb_is_broken(vp->cb_break_before, vnode)) {
+		if (op->volume->type == AFSVL_RWVOL)
+			vnode->cb_server = op->server;
+		afs_set_cb_promise(vnode, cb->expires_at, afs_cb_promise_set_apply_cb);
+	}
+}
+
+/*
+ * Apply the received status and callback to an inode all in the same critical
+ * section to avoid races with afs_validate().
+ */
+void afs_vnode_commit_status(struct afs_operation *op, struct afs_vnode_param *vp)
+{
+	struct afs_vnode *vnode = vp->vnode;
+
+	_enter("");
+
+	write_seqlock(&vnode->cb_lock);
+
+	if (vp->scb.have_error) {
+		/* A YFS server will return this from RemoveFile2 and AFS and
+		 * YFS will return this from InlineBulkStatus.
+		 */
+		if (vp->scb.status.abort_code == VNOVNODE) {
+			set_bit(AFS_VNODE_DELETED, &vnode->flags);
+			clear_nlink(&vnode->netfs.inode);
+			__afs_break_callback(vnode, afs_cb_break_for_deleted);
+			op->flags &= ~AFS_OPERATION_DIR_CONFLICT;
+		}
+	} else if (vp->scb.have_status) {
+		if (vp->speculative &&
+		    (test_bit(AFS_VNODE_MODIFYING, &vnode->flags) ||
+		     vp->dv_before != vnode->status.data_version))
+			/* Ignore the result of a speculative bulk status fetch
+			 * if it splits around a modification op, thereby
+			 * appearing to regress the data version.
+			 */
+			goto out;
+		afs_apply_status(op, vp);
+		if (vp->scb.have_cb)
+			afs_apply_callback(op, vp);
+	} else if (vp->op_unlinked && !(op->flags & AFS_OPERATION_DIR_CONFLICT)) {
+		drop_nlink(&vnode->netfs.inode);
+		if (vnode->netfs.inode.i_nlink == 0) {
+			set_bit(AFS_VNODE_DELETED, &vnode->flags);
+			__afs_break_callback(vnode, afs_cb_break_for_deleted);
+		}
+	}
+
+out:
+	write_sequnlock(&vnode->cb_lock);
+
+	if (vp->scb.have_status)
+		afs_cache_permit(vnode, op->key, vp->cb_break_before, &vp->scb);
+}
+
+static void afs_fetch_status_success(struct afs_operation *op)
+{
+	struct afs_vnode_param *vp = &op->file[op->fetch_status.which];
+	struct afs_vnode *vnode = vp->vnode;
+	int ret;
+
+	if (inode_state_read_once(&vnode->netfs.inode) & I_NEW) {
+		ret = afs_inode_init_from_status(op, vp, vnode);
+		afs_op_set_error(op, ret);
+		if (ret == 0)
+			afs_cache_permit(vnode, op->key, vp->cb_break_before, &vp->scb);
+	} else {
+		afs_vnode_commit_status(op, vp);
+	}
+}
+
+const struct afs_operation_ops afs_fetch_status_operation = {
+	.issue_afs_rpc	= afs_fs_fetch_status,
+	.issue_yfs_rpc	= yfs_fs_fetch_status,
+	.success	= afs_fetch_status_success,
+	.aborted	= afs_check_for_remote_deletion,
+};
+
+/*
+ * Fetch file status from the volume.
+ */
+int afs_fetch_status(struct afs_vnode *vnode, struct key *key, bool is_new,
+		     afs_access_t *_caller_access)
+{
+	struct afs_operation *op;
+
+	_enter("%s,{%llx:%llu.%u,S=%lx}",
+	       vnode->volume->name,
+	       vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
+	       vnode->flags);
+
+	op = afs_alloc_operation(key, vnode->volume);
+	if (IS_ERR(op))
+		return PTR_ERR(op);
+
+	afs_op_set_vnode(op, 0, vnode);
+
+	op->nr_files	= 1;
+	op->ops		= &afs_fetch_status_operation;
+	afs_begin_vnode_operation(op);
+	afs_wait_for_operation(op);
+
+	if (_caller_access)
+		*_caller_access = op->file[0].scb.status.caller_access;
+	return afs_put_operation(op);
+}
+
+/*
+ * ilookup() comparator
+ */
+int afs_ilookup5_test_by_fid(struct inode *inode, void *opaque)
+{
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	struct afs_fid *fid = opaque;
+
+	return (fid->vnode == vnode->fid.vnode &&
+		fid->vnode_hi == vnode->fid.vnode_hi &&
+		fid->unique == vnode->fid.unique);
+}
+
+/*
+ * iget5() comparator
+ */
+static int afs_iget5_test(struct inode *inode, void *opaque)
+{
+	struct afs_vnode_param *vp = opaque;
+	//struct afs_vnode *vnode = AFS_FS_I(inode);
+
+	return afs_ilookup5_test_by_fid(inode, &vp->fid);
+}
+
+/*
+ * iget5() inode initialiser
+ */
+static int afs_iget5_set(struct inode *inode, void *opaque)
+{
+	struct afs_vnode_param *vp = opaque;
+	struct afs_super_info *as = AFS_FS_S(inode->i_sb);
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+
+	vnode->volume		= as->volume;
+	vnode->fid		= vp->fid;
+
+	/* YFS supports 96-bit vnode IDs, but Linux only supports
+	 * 64-bit inode numbers.
+	 */
+	inode->i_ino		= vnode->fid.vnode;
+	inode->i_generation	= vnode->fid.unique;
+	return 0;
+}
+
+/*
+ * Get a cache cookie for an inode.
+ */
+static void afs_get_inode_cache(struct afs_vnode *vnode)
+{
+#ifdef CONFIG_AFS_FSCACHE
+	struct {
+		__be32 vnode_id;
+		__be32 unique;
+		__be32 vnode_id_ext[2];	/* Allow for a 96-bit key */
+	} __packed key;
+	struct afs_vnode_cache_aux aux;
+
+	if (vnode->status.type != AFS_FTYPE_FILE &&
+	    vnode->status.type != AFS_FTYPE_DIR &&
+	    vnode->status.type != AFS_FTYPE_SYMLINK) {
+		vnode->netfs.cache = NULL;
+		return;
+	}
+
+	key.vnode_id		= htonl(vnode->fid.vnode);
+	key.unique		= htonl(vnode->fid.unique);
+	key.vnode_id_ext[0]	= htonl(vnode->fid.vnode >> 32);
+	key.vnode_id_ext[1]	= htonl(vnode->fid.vnode_hi);
+	afs_set_cache_aux(vnode, &aux);
+
+	afs_vnode_set_cache(vnode,
+			    fscache_acquire_cookie(
+				    vnode->volume->cache,
+				    vnode->status.type == AFS_FTYPE_FILE ?
+				    0 : FSCACHE_ADV_SINGLE_CHUNK,
+				    &key, sizeof(key),
+				    &aux, sizeof(aux),
+				    i_size_read(&vnode->netfs.inode)));
+#endif
+}
+
+/*
+ * inode retrieval
+ */
+struct inode *afs_iget(struct afs_operation *op, struct afs_vnode_param *vp)
+{
+	struct afs_vnode_param *dvp = &op->file[0];
+	struct super_block *sb = dvp->vnode->netfs.inode.i_sb;
+	struct afs_vnode *vnode;
+	struct inode *inode;
+	int ret;
+
+	_enter(",{%llx:%llu.%u},,", vp->fid.vid, vp->fid.vnode, vp->fid.unique);
+
+	inode = iget5_locked(sb, vp->fid.vnode, afs_iget5_test, afs_iget5_set, vp);
+	if (!inode) {
+		_leave(" = -ENOMEM");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	vnode = AFS_FS_I(inode);
+
+	_debug("GOT INODE %p { vl=%llx vn=%llx, u=%x }",
+	       inode, vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
+
+	/* deal with an existing inode */
+	if (!(inode_state_read_once(inode) & I_NEW)) {
+		_leave(" = %p", inode);
+		return inode;
+	}
+
+	ret = afs_inode_init_from_status(op, vp, vnode);
+	if (ret < 0)
+		goto bad_inode;
+
+	afs_get_inode_cache(vnode);
+
+	/* success */
+	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
+	unlock_new_inode(inode);
+	_leave(" = %p", inode);
+	return inode;
+
+	/* failure */
+bad_inode:
+	iget_failed(inode);
+	_leave(" = %d [bad]", ret);
+	return ERR_PTR(ret);
+}
+
+static int afs_iget5_set_root(struct inode *inode, void *opaque)
+{
+	struct afs_super_info *as = AFS_FS_S(inode->i_sb);
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+
+	vnode->volume		= as->volume;
+	vnode->fid.vid		= as->volume->vid;
+	vnode->fid.vnode	= 1;
+	vnode->fid.unique	= 1;
+	inode->i_ino		= 1;
+	inode->i_generation	= 1;
+	return 0;
+}
+
+/*
+ * Set up the root inode for a volume.  This is always vnode 1, unique 1 within
+ * the volume.
+ */
+struct inode *afs_root_iget(struct super_block *sb, struct key *key)
+{
+	struct afs_super_info *as = AFS_FS_S(sb);
+	struct afs_operation *op;
+	struct afs_vnode *vnode;
+	struct inode *inode;
+	int ret;
+
+	_enter(",{%llx},,", as->volume->vid);
+
+	inode = iget5_locked(sb, 1, NULL, afs_iget5_set_root, NULL);
+	if (!inode) {
+		_leave(" = -ENOMEM");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	_debug("GOT ROOT INODE %p { vl=%llx }", inode, as->volume->vid);
+
+	BUG_ON(!(inode_state_read_once(inode) & I_NEW));
+
+	vnode = AFS_FS_I(inode);
+	vnode->cb_v_check = atomic_read(&as->volume->cb_v_break);
+
+	op = afs_alloc_operation(key, as->volume);
+	if (IS_ERR(op)) {
+		ret = PTR_ERR(op);
+		goto error;
+	}
+
+	afs_op_set_vnode(op, 0, vnode);
+
+	op->nr_files	= 1;
+	op->ops		= &afs_fetch_status_operation;
+	ret = afs_do_sync_operation(op);
+	if (ret < 0)
+		goto error;
+
+	afs_get_inode_cache(vnode);
+
+	clear_bit(AFS_VNODE_UNSET, &vnode->flags);
+	unlock_new_inode(inode);
+	_leave(" = %p", inode);
+	return inode;
+
+error:
+	iget_failed(inode);
+	_leave(" = %d [bad]", ret);
+	return ERR_PTR(ret);
+}
+
+/*
+ * read the attributes of an inode
+ */
+int afs_getattr(struct mnt_idmap *idmap, const struct path *path,
+		struct kstat *stat, u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+	struct key *key;
+	int ret, seq;
+
+	_enter("{ ino=%llu v=%u }", inode->i_ino, inode->i_generation);
+
+	if (vnode->volume &&
+	    !(query_flags & AT_STATX_DONT_SYNC) &&
+	    atomic64_read(&vnode->cb_expires_at) == AFS_NO_CB_PROMISE) {
+		key = afs_request_key(vnode->volume->cell);
+		if (IS_ERR(key))
+			return PTR_ERR(key);
+		ret = afs_validate(vnode, key);
+		key_put(key);
+		if (ret < 0)
+			return ret;
+	}
+
+	do {
+		seq = read_seqbegin(&vnode->cb_lock);
+		generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
+		if (test_bit(AFS_VNODE_SILLY_DELETED, &vnode->flags) &&
+		    stat->nlink > 0)
+			stat->nlink -= 1;
+
+		/* Lie about the size of directories.  We maintain a locally
+		 * edited copy and may make different allocation decisions on
+		 * it, but we need to give userspace the server's size.
+		 */
+		if (S_ISDIR(inode->i_mode))
+			stat->size = netfs_read_remote_i_size(inode);
+	} while (read_seqretry(&vnode->cb_lock, seq));
+
+	return 0;
+}
+
+/*
+ * discard an AFS inode
+ */
+int afs_drop_inode(struct inode *inode)
+{
+	_enter("");
+
+	if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
+		return inode_just_drop(inode);
+	else
+		return inode_generic_drop(inode);
+}
+
+/*
+ * clear an AFS inode
+ */
+void afs_evict_inode(struct inode *inode)
+{
+	struct afs_vnode_cache_aux aux;
+	struct afs_super_info *sbi = AFS_FS_S(inode->i_sb);
+	struct afs_vnode *vnode = AFS_FS_I(inode);
+
+	_enter("{%llx:%llu.%d}",
+	       vnode->fid.vid,
+	       vnode->fid.vnode,
+	       vnode->fid.unique);
+
+	_debug("CLEAR INODE %p", inode);
+
+	ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
+
+	if ((S_ISDIR(inode->i_mode) ||
+	     S_ISLNK(inode->i_mode)) &&
+	    (inode_state_read_once(inode) & I_DIRTY) &&
+	    !sbi->dyn_root) {
+		struct writeback_control wbc = {
+			.sync_mode = WB_SYNC_ALL,
+			.for_sync = true,
+			.range_end = LLONG_MAX,
+		};
+
+		inode->i_mapping->a_ops->writepages(inode->i_mapping, &wbc);
+	}
+
+	flush_delayed_work(&vnode->lock_work);
+	netfs_wait_for_outstanding_io(inode);
+	truncate_inode_pages_final(&inode->i_data);
+	netfs_free_folioq_buffer(vnode->directory);
+	if (vnode->symlink)
+		afs_evict_symlink(vnode);
+
+	afs_set_cache_aux(vnode, &aux);
+	netfs_clear_inode_writeback(inode, &aux);
+	clear_inode(inode);
+
+	while (!list_empty(&vnode->wb_keys)) {
+		struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next,
+						    struct afs_wb_key, vnode_link);
+		list_del(&wbk->vnode_link);
+		afs_put_wb_key(wbk);
+	}
+
+	fscache_relinquish_cookie(afs_vnode_cache(vnode),
+				  test_bit(AFS_VNODE_DELETED, &vnode->flags));
+
+	afs_prune_wb_keys(vnode);
+	afs_put_permits(rcu_access_pointer(vnode->permit_cache));
+	key_put(vnode->silly_key);
+	vnode->silly_key = NULL;
+	key_put(vnode->lock_key);
+	vnode->lock_key = NULL;
+	_leave("");
+}
+
+static void afs_setattr_success(struct afs_operation *op)
+{
+	struct afs_vnode_param *vp = &op->file[0];
+	struct inode *inode = &vp->vnode->netfs.inode;
+	loff_t old_i_size = i_size_read(inode);
+
+	op->setattr.old_i_size = old_i_size;
+	afs_vnode_commit_status(op, vp);
+	/* inode->i_size has now been changed. */
+
+	if (op->setattr.attr->ia_valid & ATTR_SIZE) {
+		loff_t size = op->setattr.attr->ia_size;
+		if (size > old_i_size)
+			pagecache_isize_extended(inode, old_i_size, size);
+	}
+}
+
+static void afs_setattr_edit_file(struct afs_operation *op)
+{
+	struct afs_vnode_param *vp = &op->file[0];
+	struct afs_vnode *vnode = vp->vnode;
+	struct inode *inode = &vnode->netfs.inode;
+
+	if (op->setattr.attr->ia_valid & ATTR_SIZE) {
+		loff_t size = op->setattr.attr->ia_size;
+		loff_t old = op->setattr.old_i_size;
+
+		/* Note: inode->i_size was updated by afs_apply_status() inside
+		 * the I/O and callback locks.
+		 */
+
+		if (size != old) {
+			truncate_pagecache(inode, size);
+			netfs_resize_file(&vnode->netfs, size, true);
+			fscache_resize_cookie(afs_vnode_cache(vnode), size);
+		}
+	}
+}
+
+static const struct afs_operation_ops afs_setattr_operation = {
+	.issue_afs_rpc	= afs_fs_setattr,
+	.issue_yfs_rpc	= yfs_fs_setattr,
+	.success	= afs_setattr_success,
+	.edit_dir	= afs_setattr_edit_file,
+};
+
+/*
+ * set the attributes of an inode
+ */
+int afs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+		struct iattr *attr)
+{
+	const unsigned int supported =
+		ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
+		ATTR_MTIME | ATTR_MTIME_SET | ATTR_TIMES_SET | ATTR_TOUCH;
+	struct afs_operation *op;
+	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
+	struct inode *inode = &vnode->netfs.inode;
+	loff_t i_size;
+	int ret;
+
+	_enter("{%llx:%llu},{n=%pd},%x",
+	       vnode->fid.vid, vnode->fid.vnode, dentry,
+	       attr->ia_valid);
+
+	if (!(attr->ia_valid & supported)) {
+		_leave(" = 0 [unsupported]");
+		return 0;
+	}
+
+	i_size = i_size_read(inode);
+	if (attr->ia_valid & ATTR_SIZE) {
+		if (!S_ISREG(inode->i_mode))
+			return -EISDIR;
+
+		ret = inode_newsize_ok(inode, attr->ia_size);
+		if (ret)
+			return ret;
+
+		if (attr->ia_size == i_size)
+			attr->ia_valid &= ~ATTR_SIZE;
+	}
+
+	fscache_use_cookie(afs_vnode_cache(vnode), true);
+
+	/* Prevent any new writebacks from starting whilst we do this. */
+	down_write(&vnode->validate_lock);
+
+	if ((attr->ia_valid & ATTR_SIZE) && S_ISREG(inode->i_mode)) {
+		loff_t size = attr->ia_size;
+
+		/* Wait for any outstanding writes to the server to complete */
+		loff_t from = min(size, i_size);
+		loff_t to = max(size, i_size);
+		ret = filemap_fdatawait_range(inode->i_mapping, from, to);
+		if (ret < 0)
+			goto out_unlock;
+
+		/* Don't talk to the server if we're just shortening in-memory
+		 * writes that haven't gone to the server yet.
+		 */
+		if (!(attr->ia_valid & (supported & ~ATTR_SIZE & ~ATTR_MTIME)) &&
+		    attr->ia_size < i_size &&
+		    attr->ia_size > netfs_read_remote_i_size(inode)) {
+			truncate_setsize(inode, attr->ia_size);
+			netfs_resize_file(&vnode->netfs, size, false);
+			fscache_resize_cookie(afs_vnode_cache(vnode),
+					      attr->ia_size);
+			ret = 0;
+			goto out_unlock;
+		}
+	}
+
+	op = afs_alloc_operation(((attr->ia_valid & ATTR_FILE) ?
+				  afs_file_key(attr->ia_file) : NULL),
+				 vnode->volume);
+	if (IS_ERR(op)) {
+		ret = PTR_ERR(op);
+		goto out_unlock;
+	}
+
+	afs_op_set_vnode(op, 0, vnode);
+	op->setattr.attr = attr;
+
+	if (attr->ia_valid & ATTR_SIZE) {
+		op->file[0].dv_delta = 1;
+		op->file[0].set_size = true;
+	}
+	op->ctime = attr->ia_ctime;
+	op->file[0].update_ctime = 1;
+	op->file[0].modification = true;
+
+	op->ops = &afs_setattr_operation;
+	ret = afs_do_sync_operation(op);
+
+out_unlock:
+	up_write(&vnode->validate_lock);
+	fscache_unuse_cookie(afs_vnode_cache(vnode), NULL, NULL);
+	_leave(" = %d", ret);
+	return ret;
+}