Merge tag 'afs-fixes-b-20190516' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull AFS callback promise fixes from David Howells:
 "This series fixes a bunch of problems in callback promise handling,
  where a callback promise indicates a promise on the part of the server
  to notify the client in the event of some sort of change to a file or
  volume. In the event of a break, the client has to go and refetch the
  client status from the server and discard any cached permission
  information as the ACL might have changed.

  The problem in the current code is that changes made by other clients
  aren't always noticed, primarily because the file status information
  and the callback information aren't updated in the same critical
  section, even if these are carried in the same reply from an RPC
  operation, and so the AFS_VNODE_CB_PROMISED flag is unreliable.

  Arranging for them to be done in the same critical section during
  reply decoding is tricky because of the FS.InlineBulkStatus op - which
  has all the statuses in the reply arriving and then all the callbacks,
  so they have to be buffered. It simplifies things a lot to move the
  critical section out of the decode phase and do it after the RPC
  function returns.

  Also new inodes (either newly fetched or newly created) aren't
  properly managed against a callback break happening before we get the
  local inode up and running.

  Fix this by:

   - There's now a combined file status and callback record (struct
     afs_status_cb) to carry both plus some flags.

   - Each operation wrapper function allocates sufficient afs_status_cb
     records for all the vnodes it is interested in and passes them into
     RPC operations to be filled in from the reply.

   - The FileStatus and CallBack record decoders no longer apply the
     new/revised status and callback information to the inode/vnode at
     the point of decoding and instead store the information into the
     record from (2).

   - afs_vnode_commit_status() then revises the file status, detects
     deletion and notes callback information inside of a single critical
     section. It also checks the callback break counters and cancels the
     callback promise if they changed during the operation.

     [*] Note that "callback break counters" are counters of server
     events that cancel one or more callback promises that the client
     thinks it has. The client counts the events and compares the
     counters before and after an operation to see if the callback
     promise it thinks it just got evaporated before it got recorded
     under lock.

   - Volume and server callback break counters are passed into
     afs_iget() allowing callback breaks concurrent with inode set up to
     be detected and the callback promise thence to be cancelled.

   - AFS validation checks are now done under RCU conditions using a
     read lock on cb_lock. This requires vnode->cb_interest to be made
     RCU safe.

   - If the checks in (6) fail, the callback breaker is then called
     under write lock on the cb_lock - but only if the callback break
     counter didn't change from the value read before the checks were
     made.

   - Results from FS.InlineBulkStatus that correspond to inodes we
     currently have in memory are now used to update those inodes'
     status and callback information rather than being discarded. This
     requires those inodes to be looked up before the RPC op is made and
     all their callback break values saved.

  To aid in this, the following changes have also been made:

   - Don't pass the vnode into the reply delivery functions or the
     decoders. The vnode shouldn't be altered anywhere in those paths.
     The only exception, for the moment, is for the call done hook for
     file lock ops that wants access to both the vnode and the call -
     this can be fixed at a later time.

   - Get rid of the call->reply[] void* array and replace it with named
     and typed members. This avoids confusion since different ops were
     mapping different reply[] members to different things.

   - Fix an order-1 kmalloc allocation in afs_do_lookup() and replace it
     with kvcalloc().

   - Always get the reply time. Since callback, lock and fileserver
     record expiry times are calculated for several RPCs, make this
     mandatory.

   - Call afs_pages_written_back() from the operation wrapper rather
     than from the delivery function.

   - Don't store the version and type from a callback promise in a reply
     as the information in them is of very limited use"

* tag 'afs-fixes-b-20190516' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix application of the results of a inline bulk status fetch
  afs: Pass pre-fetch server and volume break counts into afs_iget5_set()
  afs: Fix unlink to handle YFS.RemoveFile2 better
  afs: Clear AFS_VNODE_CB_PROMISED if we detect callback expiry
  afs: Make vnode->cb_interest RCU safe
  afs: Split afs_validate() so first part can be used under LOOKUP_RCU
  afs: Don't save callback version and type fields
  afs: Fix application of status and callback to be under same lock
  afs: Always get the reply time
  afs: Fix order-1 allocation in afs_do_lookup()
  afs: Get rid of afs_call::reply[]
  afs: Don't pass the vnode pointer through into the inline bulk status op

20 files changed, 1383 insertions, 1381 deletions

diff --git a/fs/afs/afs.h b/fs/afs/afs.h
index 74913c707bba..3f4e460c6655 100644
--- a/fs/afs/afs.h
+++ b/fs/afs/afs.h
@@ -72,8 +72,8 @@ typedef enum {
 
 struct afs_callback {
 	time64_t		expires_at;	/* Time at which expires */
-	unsigned		version;	/* Callback version */
-	afs_callback_type_t	type;		/* Type of callback */
+	//unsigned		version;	/* Callback version */
+	//afs_callback_type_t	type;		/* Type of callback */
 };
 
 struct afs_callback_break {
@@ -147,6 +147,15 @@ struct afs_file_status {
 	u32			abort_code;	/* Abort if bulk-fetching this failed */
 };
 
+struct afs_status_cb {
+	struct afs_file_status	status;
+	struct afs_callback	callback;
+	unsigned int		cb_break;	/* Pre-op callback break counter */
+	bool			have_status;	/* True if status record was retrieved */
+	bool			have_cb;	/* True if cb record was retrieved */
+	bool			have_error;	/* True if status.abort_code indicates an error */
+};
+
 /*
  * AFS file status change request
  */
diff --git a/fs/afs/callback.c b/fs/afs/callback.c
index 4876079aa643..d441bef72163 100644
--- a/fs/afs/callback.c
+++ b/fs/afs/callback.c
@@ -94,15 +94,15 @@ int afs_register_server_cb_interest(struct afs_vnode *vnode,
 	struct afs_server *server = entry->server;
 
 again:
-	if (vnode->cb_interest &&
-	    likely(vnode->cb_interest == entry->cb_interest))
+	vcbi = rcu_dereference_protected(vnode->cb_interest,
+					 lockdep_is_held(&vnode->io_lock));
+	if (vcbi && likely(vcbi == entry->cb_interest))
 		return 0;
 
 	read_lock(&slist->lock);
 	cbi = afs_get_cb_interest(entry->cb_interest);
 	read_unlock(&slist->lock);
 
-	vcbi = vnode->cb_interest;
 	if (vcbi) {
 		if (vcbi == cbi) {
 			afs_put_cb_interest(afs_v2net(vnode), cbi);
@@ -114,8 +114,9 @@ again:
 		 */
 		if (cbi && vcbi->server == cbi->server) {
 			write_seqlock(&vnode->cb_lock);
-			old = vnode->cb_interest;
-			vnode->cb_interest = cbi;
+			old = rcu_dereference_protected(vnode->cb_interest,
+							lockdep_is_held(&vnode->cb_lock.lock));
+			rcu_assign_pointer(vnode->cb_interest, cbi);
 			write_sequnlock(&vnode->cb_lock);
 			afs_put_cb_interest(afs_v2net(vnode), old);
 			return 0;
@@ -160,8 +161,9 @@ again:
 	 */
 	write_seqlock(&vnode->cb_lock);
 
-	old = vnode->cb_interest;
-	vnode->cb_interest = cbi;
+	old = rcu_dereference_protected(vnode->cb_interest,
+					lockdep_is_held(&vnode->cb_lock.lock));
+	rcu_assign_pointer(vnode->cb_interest, cbi);
 	vnode->cb_s_break = cbi->server->cb_s_break;
 	vnode->cb_v_break = vnode->volume->cb_v_break;
 	clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
@@ -191,10 +193,11 @@ void afs_put_cb_interest(struct afs_net *net, struct afs_cb_interest *cbi)
 				vi = NULL;
 
 			write_unlock(&cbi->server->cb_break_lock);
-			kfree(vi);
+			if (vi)
+				kfree_rcu(vi, rcu);
 			afs_put_server(net, cbi->server);
 		}
-		kfree(cbi);
+		kfree_rcu(cbi, rcu);
 	}
 }
 
diff --git a/fs/afs/cmservice.c b/fs/afs/cmservice.c
index 748090014519..01437cfe5432 100644
--- a/fs/afs/cmservice.c
+++ b/fs/afs/cmservice.c
@@ -213,7 +213,7 @@ static int afs_find_cm_server_by_peer(struct afs_call *call)
 		return 0;
 	}
 
-	call->cm_server = server;
+	call->server = server;
 	return afs_record_cm_probe(call, server);
 }
 
@@ -234,7 +234,7 @@ static int afs_find_cm_server_by_uuid(struct afs_call *call,
 		return 0;
 	}
 
-	call->cm_server = server;
+	call->server = server;
 	return afs_record_cm_probe(call, server);
 }
 
@@ -260,8 +260,8 @@ static void SRXAFSCB_CallBack(struct work_struct *work)
 	 * server holds up change visibility till it receives our reply so as
 	 * to maintain cache coherency.
 	 */
-	if (call->cm_server)
-		afs_break_callbacks(call->cm_server, call->count, call->request);
+	if (call->server)
+		afs_break_callbacks(call->server, call->count, call->request);
 
 	afs_send_empty_reply(call);
 	afs_put_call(call);
@@ -376,10 +376,10 @@ static void SRXAFSCB_InitCallBackState(struct work_struct *work)
 {
 	struct afs_call *call = container_of(work, struct afs_call, work);
 
-	_enter("{%p}", call->cm_server);
+	_enter("{%p}", call->server);
 
-	if (call->cm_server)
-		afs_init_callback_state(call->cm_server);
+	if (call->server)
+		afs_init_callback_state(call->server);
 	afs_send_empty_reply(call);
 	afs_put_call(call);
 	_leave("");
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index c15550310f62..79d93a26759a 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -18,6 +18,7 @@
 #include <linux/sched.h>
 #include <linux/task_io_accounting_ops.h>
 #include "internal.h"
+#include "afs_fs.h"
 #include "xdr_fs.h"
 
 static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
@@ -102,8 +103,8 @@ struct afs_lookup_cookie {
 	bool			found;
 	bool			one_only;
 	unsigned short		nr_fids;
-	struct afs_file_status	*statuses;
-	struct afs_callback	*callbacks;
+	struct inode		**inodes;
+	struct afs_status_cb	*statuses;
 	struct afs_fid		fids[50];
 };
 
@@ -638,12 +639,14 @@ static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
 				   struct key *key)
 {
 	struct afs_lookup_cookie *cookie;
-	struct afs_cb_interest *cbi = NULL;
+	struct afs_cb_interest *dcbi, *cbi = NULL;
 	struct afs_super_info *as = dir->i_sb->s_fs_info;
-	struct afs_iget_data data;
+	struct afs_status_cb *scb;
+	struct afs_iget_data iget_data;
 	struct afs_fs_cursor fc;
-	struct afs_vnode *dvnode = AFS_FS_I(dir);
-	struct inode *inode = NULL;
+	struct afs_server *server;
+	struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode;
+	struct inode *inode = NULL, *ti;
 	int ret, i;
 
 	_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
@@ -657,10 +660,14 @@ static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
 	cookie->nr_fids = 1; /* slot 0 is saved for the fid we actually want */
 
 	read_seqlock_excl(&dvnode->cb_lock);
-	if (dvnode->cb_interest &&
-	    dvnode->cb_interest->server &&
-	    test_bit(AFS_SERVER_FL_NO_IBULK, &dvnode->cb_interest->server->flags))
-		cookie->one_only = true;
+	dcbi = rcu_dereference_protected(dvnode->cb_interest,
+					 lockdep_is_held(&dvnode->cb_lock.lock));
+	if (dcbi) {
+		server = dcbi->server;
+		if (server &&
+		    test_bit(AFS_SERVER_FL_NO_IBULK, &server->flags))
+			cookie->one_only = true;
+	}
 	read_sequnlock_excl(&dvnode->cb_lock);
 
 	for (i = 0; i < 50; i++)
@@ -678,24 +685,43 @@ static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
 		goto out;
 
 	/* Check to see if we already have an inode for the primary fid. */
-	data.volume = dvnode->volume;
-	data.fid = cookie->fids[0];
-	inode = ilookup5(dir->i_sb, cookie->fids[0].vnode, afs_iget5_test, &data);
+	iget_data.fid = cookie->fids[0];
+	iget_data.volume = dvnode->volume;
+	iget_data.cb_v_break = dvnode->volume->cb_v_break;
+	iget_data.cb_s_break = 0;
+	inode = ilookup5(dir->i_sb, cookie->fids[0].vnode,
+			 afs_iget5_test, &iget_data);
 	if (inode)
 		goto out;
 
 	/* Need space for examining all the selected files */
 	inode = ERR_PTR(-ENOMEM);
-	cookie->statuses = kcalloc(cookie->nr_fids, sizeof(struct afs_file_status),
-				   GFP_KERNEL);
+	cookie->statuses = kvcalloc(cookie->nr_fids, sizeof(struct afs_status_cb),
+				    GFP_KERNEL);
 	if (!cookie->statuses)
 		goto out;
 
-	cookie->callbacks = kcalloc(cookie->nr_fids, sizeof(struct afs_callback),
-				    GFP_KERNEL);
-	if (!cookie->callbacks)
+	cookie->inodes = kcalloc(cookie->nr_fids, sizeof(struct inode *),
+				 GFP_KERNEL);
+	if (!cookie->inodes)
 		goto out_s;
 
+	for (i = 1; i < cookie->nr_fids; i++) {
+		scb = &cookie->statuses[i];
+
+		/* Find any inodes that already exist and get their
+		 * callback counters.
+		 */
+		iget_data.fid = cookie->fids[i];
+		ti = ilookup5_nowait(dir->i_sb, iget_data.fid.vnode,
+				     afs_iget5_test, &iget_data);
+		if (!IS_ERR_OR_NULL(ti)) {
+			vnode = AFS_FS_I(ti);
+			scb->cb_break = afs_calc_vnode_cb_break(vnode);
+			cookie->inodes[i] = ti;
+		}
+	}
+
 	/* Try FS.InlineBulkStatus first.  Abort codes for the individual
 	 * lookups contained therein are stored in the reply without aborting
 	 * the whole operation.
@@ -712,11 +738,12 @@ static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
 				fc.ac.error = -ECONNABORTED;
 				break;
 			}
+			iget_data.cb_v_break = dvnode->volume->cb_v_break;
+			iget_data.cb_s_break = fc.cbi->server->cb_s_break;
 			afs_fs_inline_bulk_status(&fc,
 						  afs_v2net(dvnode),
 						  cookie->fids,
 						  cookie->statuses,
-						  cookie->callbacks,
 						  cookie->nr_fids, NULL);
 		}
 
@@ -737,15 +764,16 @@ no_inline_bulk_status:
 	 * any of the lookups fails - so, for the moment, revert to
 	 * FS.FetchStatus for just the primary fid.
 	 */
-	cookie->nr_fids = 1;
 	inode = ERR_PTR(-ERESTARTSYS);
 	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
 		while (afs_select_fileserver(&fc)) {
+			iget_data.cb_v_break = dvnode->volume->cb_v_break;
+			iget_data.cb_s_break = fc.cbi->server->cb_s_break;
+			scb = &cookie->statuses[0];
 			afs_fs_fetch_status(&fc,
 					    afs_v2net(dvnode),
 					    cookie->fids,
-					    cookie->statuses,
-					    cookie->callbacks,
+					    scb,
 					    NULL);
 		}
 
@@ -757,26 +785,36 @@ no_inline_bulk_status:
 	if (IS_ERR(inode))
 		goto out_c;
 
-	for (i = 0; i < cookie->nr_fids; i++)
-		cookie->statuses[i].abort_code = 0;
-
 success:
 	/* Turn all the files into inodes and save the first one - which is the
 	 * one we actually want.
 	 */
-	if (cookie->statuses[0].abort_code != 0)
-		inode = ERR_PTR(afs_abort_to_error(cookie->statuses[0].abort_code));
+	scb = &cookie->statuses[0];
+	if (scb->status.abort_code != 0)
+		inode = ERR_PTR(afs_abort_to_error(scb->status.abort_code));
 
 	for (i = 0; i < cookie->nr_fids; i++) {
-		struct inode *ti;
+		struct afs_status_cb *scb = &cookie->statuses[i];
+
+		if (!scb->have_status && !scb->have_error)
+			continue;
+
+		if (cookie->inodes[i]) {
+			afs_vnode_commit_status(&fc, AFS_FS_I(cookie->inodes[i]),
+						scb->cb_break, NULL, scb);
+			continue;
+		}
 
-		if (cookie->statuses[i].abort_code != 0)
+		if (scb->status.abort_code != 0)
 			continue;
 
-		ti = afs_iget(dir->i_sb, key, &cookie->fids[i],
-			      &cookie->statuses[i],
-			      &cookie->callbacks[i],
-			      cbi, dvnode);
+		iget_data.fid = cookie->fids[i];
+		ti = afs_iget(dir->i_sb, key, &iget_data, scb, cbi, dvnode);
+		if (!IS_ERR(ti))
+			afs_cache_permit(AFS_FS_I(ti), key,
+					 0 /* Assume vnode->cb_break is 0 */ +
+					 iget_data.cb_v_break,
+					 scb);
 		if (i == 0) {
 			inode = ti;
 		} else {
@@ -787,9 +825,13 @@ success:
 
 out_c:
 	afs_put_cb_interest(afs_v2net(dvnode), cbi);
-	kfree(cookie->callbacks);
+	if (cookie->inodes) {
+		for (i = 0; i < cookie->nr_fids; i++)
+			iput(cookie->inodes[i]);
+		kfree(cookie->inodes);
+	}
 out_s:
-	kfree(cookie->statuses);
+	kvfree(cookie->statuses);
 out:
 	kfree(cookie);
 	return inode;
@@ -1114,9 +1156,8 @@ void afs_d_release(struct dentry *dentry)
  */
 static void afs_vnode_new_inode(struct afs_fs_cursor *fc,
 				struct dentry *new_dentry,
-				struct afs_fid *newfid,
-				struct afs_file_status *newstatus,
-				struct afs_callback *newcb)
+				struct afs_iget_data *new_data,
+				struct afs_status_cb *new_scb)
 {
 	struct afs_vnode *vnode;
 	struct inode *inode;
@@ -1125,7 +1166,7 @@ static void afs_vnode_new_inode(struct afs_fs_cursor *fc,
 		return;
 
 	inode = afs_iget(fc->vnode->vfs_inode.i_sb, fc->key,
-			 newfid, newstatus, newcb, fc->cbi, fc->vnode);
+			 new_data, new_scb, fc->cbi, fc->vnode);
 	if (IS_ERR(inode)) {
 		/* ENOMEM or EINTR at a really inconvenient time - just abandon
 		 * the new directory on the server.
@@ -1136,22 +1177,29 @@ static void afs_vnode_new_inode(struct afs_fs_cursor *fc,
 
 	vnode = AFS_FS_I(inode);
 	set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
-	afs_vnode_commit_status(fc, vnode, 0);
+	if (fc->ac.error == 0)
+		afs_cache_permit(vnode, fc->key, vnode->cb_break, new_scb);
 	d_instantiate(new_dentry, inode);
 }
 
+static void afs_prep_for_new_inode(struct afs_fs_cursor *fc,
+				   struct afs_iget_data *iget_data)
+{
+	iget_data->volume = fc->vnode->volume;
+	iget_data->cb_v_break = fc->vnode->volume->cb_v_break;
+	iget_data->cb_s_break = fc->cbi->server->cb_s_break;
+}
+
 /*
  * create a directory on an AFS filesystem
  */
 static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
-	struct afs_file_status newstatus;
+	struct afs_iget_data iget_data;
+	struct afs_status_cb *scb;
 	struct afs_fs_cursor fc;
-	struct afs_callback newcb;
 	struct afs_vnode *dvnode = AFS_FS_I(dir);
-	struct afs_fid newfid;
 	struct key *key;
-	u64 data_version = dvnode->status.data_version;
 	int ret;
 
 	mode |= S_IFDIR;
@@ -1159,23 +1207,32 @@ static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	_enter("{%llx:%llu},{%pd},%ho",
 	       dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);
 
+	ret = -ENOMEM;
+	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
+	if (!scb)
+		goto error;
+
 	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);
-		goto error;
+		goto error_scb;
 	}
 
 	ret = -ERESTARTSYS;
 	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
+		afs_dataversion_t data_version = dvnode->status.data_version + 1;
+
 		while (afs_select_fileserver(&fc)) {
 			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
-			afs_fs_create(&fc, dentry->d_name.name, mode, data_version,
-				      &newfid, &newstatus, &newcb);
+			afs_prep_for_new_inode(&fc, &iget_data);
+			afs_fs_create(&fc, dentry->d_name.name, mode,
+				      &scb[0], &iget_data.fid, &scb[1]);
 		}
 
-		afs_check_for_remote_deletion(&fc, fc.vnode);
-		afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
-		afs_vnode_new_inode(&fc, dentry, &newfid, &newstatus, &newcb);
+		afs_check_for_remote_deletion(&fc, dvnode);
+		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
+					&data_version, &scb[0]);
+		afs_vnode_new_inode(&fc, dentry, &iget_data, &scb[1]);
 		ret = afs_end_vnode_operation(&fc);
 		if (ret < 0)
 			goto error_key;
@@ -1185,15 +1242,18 @@ static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 
 	if (ret == 0 &&
 	    test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
-		afs_edit_dir_add(dvnode, &dentry->d_name, &newfid,
+		afs_edit_dir_add(dvnode, &dentry->d_name, &iget_data.fid,
 				 afs_edit_dir_for_create);
 
 	key_put(key);
+	kfree(scb);
 	_leave(" = 0");
 	return 0;
 
 error_key:
 	key_put(key);
+error_scb:
+	kfree(scb);
 error:
 	d_drop(dentry);
 	_leave(" = %d", ret);
@@ -1220,15 +1280,19 @@ static void afs_dir_remove_subdir(struct dentry *dentry)
  */
 static int afs_rmdir(struct inode *dir, struct dentry *dentry)
 {
+	struct afs_status_cb *scb;
 	struct afs_fs_cursor fc;
 	struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode = NULL;
 	struct key *key;
-	u64 data_version = dvnode->status.data_version;
 	int ret;
 
 	_enter("{%llx:%llu},{%pd}",
 	       dvnode->fid.vid, dvnode->fid.vnode, dentry);
 
+	scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL);
+	if (!scb)
+		return -ENOMEM;
+
 	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);
@@ -1251,13 +1315,15 @@ static int afs_rmdir(struct inode *dir, struct dentry *dentry)
 
 	ret = -ERESTARTSYS;
 	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
+		afs_dataversion_t data_version = dvnode->status.data_version + 1;
+
 		while (afs_select_fileserver(&fc)) {
 			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
-			afs_fs_remove(&fc, vnode, dentry->d_name.name, true,
-				      data_version);
+			afs_fs_remove(&fc, vnode, dentry->d_name.name, true, scb);
 		}
 
-		afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
+		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
+					&data_version, scb);
 		ret = afs_end_vnode_operation(&fc);
 		if (ret == 0) {
 			afs_dir_remove_subdir(dentry);
@@ -1272,6 +1338,7 @@ static int afs_rmdir(struct inode *dir, struct dentry *dentry)
 error_key:
 	key_put(key);
 error:
+	kfree(scb);
 	return ret;
 }
 
@@ -1285,32 +1352,27 @@ error:
  * However, if we didn't have a callback promise outstanding, or it was
  * outstanding on a different server, then it won't break it either...
  */
-int afs_dir_remove_link(struct dentry *dentry, struct key *key,
-			unsigned long d_version_before,
-			unsigned long d_version_after)
+static int afs_dir_remove_link(struct afs_vnode *dvnode, struct dentry *dentry,
+			       struct key *key)
 {
-	bool dir_valid;
 	int ret = 0;
 
-	/* There were no intervening changes on the server if the version
-	 * number we got back was incremented by exactly 1.
-	 */
-	dir_valid = (d_version_after == d_version_before + 1);
-
 	if (d_really_is_positive(dentry)) {
 		struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
 
 		if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
 			/* Already done */
-		} else if (dir_valid) {
+		} else if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) {
+			write_seqlock(&vnode->cb_lock);
 			drop_nlink(&vnode->vfs_inode);
 			if (vnode->vfs_inode.i_nlink == 0) {
 				set_bit(AFS_VNODE_DELETED, &vnode->flags);
-				clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
+				__afs_break_callback(vnode);
 			}
+			write_sequnlock(&vnode->cb_lock);
 			ret = 0;
 		} else {
-			clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
+			afs_break_callback(vnode);
 
 			if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
 				kdebug("AFS_VNODE_DELETED");
@@ -1331,11 +1393,10 @@ int afs_dir_remove_link(struct dentry *dentry, struct key *key,
 static int afs_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct afs_fs_cursor fc;
+	struct afs_status_cb *scb;
 	struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode = NULL;
 	struct key *key;
-	unsigned long d_version = (unsigned long)dentry->d_fsdata;
 	bool need_rehash = false;
-	u64 data_version = dvnode->status.data_version;
 	int ret;
 
 	_enter("{%llx:%llu},{%pd}",
@@ -1344,10 +1405,15 @@ static int afs_unlink(struct inode *dir, struct dentry *dentry)
 	if (dentry->d_name.len >= AFSNAMEMAX)
 		return -ENAMETOOLONG;
 
+	ret = -ENOMEM;
+	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
+	if (!scb)
+		goto error;
+
 	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);
-		goto error;
+		goto error_scb;
 	}
 
 	/* Try to make sure we have a callback promise on the victim. */
@@ -1375,29 +1441,33 @@ static int afs_unlink(struct inode *dir, struct dentry *dentry)
 
 	ret = -ERESTARTSYS;
 	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
+		afs_dataversion_t data_version = dvnode->status.data_version + 1;
+		afs_dataversion_t data_version_2 = vnode->status.data_version;
+
 		while (afs_select_fileserver(&fc)) {
 			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
+			fc.cb_break_2 = afs_calc_vnode_cb_break(vnode);
 
 			if (test_bit(AFS_SERVER_FL_IS_YFS, &fc.cbi->server->flags) &&
 			    !test_bit(AFS_SERVER_FL_NO_RM2, &fc.cbi->server->flags)) {
 				yfs_fs_remove_file2(&fc, vnode, dentry->d_name.name,
-						    data_version);
+						    &scb[0], &scb[1]);
 				if (fc.ac.error != -ECONNABORTED ||
 				    fc.ac.abort_code != RXGEN_OPCODE)
 					continue;
 				set_bit(AFS_SERVER_FL_NO_RM2, &fc.cbi->server->flags);
 			}
 
-			afs_fs_remove(&fc, vnode, dentry->d_name.name, false,
-				      data_version);
+			afs_fs_remove(&fc, vnode, dentry->d_name.name, false, &scb[0]);
 		}
 
-		afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
+		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
+					&data_version, &scb[0]);
+		afs_vnode_commit_status(&fc, vnode, fc.cb_break_2,
+					&data_version_2, &scb[1]);
 		ret = afs_end_vnode_operation(&fc);
-		if (ret == 0)
-			ret = afs_dir_remove_link(
-				dentry, key, d_version,
-				(unsigned long)dvnode->status.data_version);
+		if (ret == 0 && !(scb[1].have_status || scb[1].have_error))
+			ret = afs_dir_remove_link(dvnode, dentry, key);
 		if (ret == 0 &&
 		    test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
 			afs_edit_dir_remove(dvnode, &dentry->d_name,
@@ -1409,6 +1479,8 @@ static int afs_unlink(struct inode *dir, struct dentry *dentry)
 
 error_key:
 	key_put(key);
+error_scb:
+	kfree(scb);
 error:
 	_leave(" = %d", ret);
 	return ret;
@@ -1420,13 +1492,11 @@ error:
 static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 		      bool excl)
 {
+	struct afs_iget_data iget_data;
 	struct afs_fs_cursor fc;
-	struct afs_file_status newstatus;
-	struct afs_callback newcb;
+	struct afs_status_cb *scb;
 	struct afs_vnode *dvnode = AFS_FS_I(dir);
-	struct afs_fid newfid;
 	struct key *key;
-	u64 data_version = dvnode->status.data_version;
 	int ret;
 
 	mode |= S_IFREG;
@@ -1444,17 +1514,26 @@ static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 		goto error;
 	}
 
+	ret = -ENOMEM;
+	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
+	if (!scb)
+		goto error_scb;
+
 	ret = -ERESTARTSYS;
 	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
+		afs_dataversion_t data_version = dvnode->status.data_version + 1;
+
 		while (afs_select_fileserver(&fc)) {
 			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
-			afs_fs_create(&fc, dentry->d_name.name, mode, data_version,
-				      &newfid, &newstatus, &newcb);
+			afs_prep_for_new_inode(&fc, &iget_data);
+			afs_fs_create(&fc, dentry->d_name.name, mode,
+				      &scb[0], &iget_data.fid, &scb[1]);
 		}
 
-		afs_check_for_remote_deletion(&fc, fc.vnode);
-		afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
-		afs_vnode_new_inode(&fc, dentry, &newfid, &newstatus, &newcb);
+		afs_check_for_remote_deletion(&fc, dvnode);
+		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
+					&data_version, &scb[0]);
+		afs_vnode_new_inode(&fc, dentry, &iget_data, &scb[1]);
 		ret = afs_end_vnode_operation(&fc);
 		if (ret < 0)
 			goto error_key;
@@ -1463,13 +1542,16 @@ static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 	}
 
 	if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
-		afs_edit_dir_add(dvnode, &dentry->d_name, &newfid,
+		afs_edit_dir_add(dvnode, &dentry->d_name, &iget_data.fid,
 				 afs_edit_dir_for_create);
 
+	kfree(scb);
 	key_put(key);
 	_leave(" = 0");
 	return 0;
 
+error_scb:
+	kfree(scb);
 error_key:
 	key_put(key);
 error:
@@ -1485,15 +1567,12 @@ static int afs_link(struct dentry *from, struct inode *dir,
 		    struct dentry *dentry)
 {
 	struct afs_fs_cursor fc;
-	struct afs_vnode *dvnode, *vnode;
+	struct afs_status_cb *scb;
+	struct afs_vnode *dvnode = AFS_FS_I(dir);
+	struct afs_vnode *vnode = AFS_FS_I(d_inode(from));
 	struct key *key;
-	u64 data_version;
 	int ret;
 
-	vnode = AFS_FS_I(d_inode(from));
-	dvnode = AFS_FS_I(dir);
-	data_version = dvnode->status.data_version;
-
 	_enter("{%llx:%llu},{%llx:%llu},{%pd}",
 	       vnode->fid.vid, vnode->fid.vnode,
 	       dvnode->fid.vid, dvnode->fid.vnode,
@@ -1503,14 +1582,21 @@ static int afs_link(struct dentry *from, struct inode *dir,
 	if (dentry->d_name.len >= AFSNAMEMAX)
 		goto error;
 
+	ret = -ENOMEM;
+	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
+	if (!scb)
+		goto error;
+
 	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);
-		goto error;
+		goto error_scb;
 	}
 
 	ret = -ERESTARTSYS;
 	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
+		afs_dataversion_t data_version = dvnode->status.data_version + 1;
+
 		if (mutex_lock_interruptible_nested(&vnode->io_lock, 1) < 0) {
 			afs_end_vnode_operation(&fc);
 			goto error_key;
@@ -1519,11 +1605,14 @@ static int afs_link(struct dentry *from, struct inode *dir,
 		while (afs_select_fileserver(&fc)) {
 			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
 			fc.cb_break_2 = afs_calc_vnode_cb_break(vnode);
-			afs_fs_link(&fc, vnode, dentry->d_name.name, data_version);
+			afs_fs_link(&fc, vnode, dentry->d_name.name,
+				    &scb[0], &scb[1]);
 		}
 
-		afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
-		afs_vnode_commit_status(&fc, vnode, fc.cb_break_2);
+		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
+					&data_version, &scb[0]);
+		afs_vnode_commit_status(&fc, vnode, fc.cb_break_2,
+					NULL, &scb[1]);
 		ihold(&vnode->vfs_inode);
 		d_instantiate(dentry, &vnode->vfs_inode);
 
@@ -1540,11 +1629,14 @@ static int afs_link(struct dentry *from, struct inode *dir,
 				 afs_edit_dir_for_link);
 
 	key_put(key);
+	kfree(scb);
 	_leave(" = 0");
 	return 0;
 
 error_key:
 	key_put(key);
+error_scb:
+	kfree(scb);
 error:
 	d_drop(dentry);
 	_leave(" = %d", ret);
@@ -1557,12 +1649,11 @@ error:
 static int afs_symlink(struct inode *dir, struct dentry *dentry,
 		       const char *content)
 {
+	struct afs_iget_data iget_data;
 	struct afs_fs_cursor fc;
-	struct afs_file_status newstatus;
+	struct afs_status_cb *scb;
 	struct afs_vnode *dvnode = AFS_FS_I(dir);
-	struct afs_fid newfid;
 	struct key *key;
-	u64 data_version = dvnode->status.data_version;
 	int ret;
 
 	_enter("{%llx:%llu},{%pd},%s",
@@ -1577,24 +1668,32 @@ static int afs_symlink(struct inode *dir, struct dentry *dentry,
 	if (strlen(content) >= AFSPATHMAX)
 		goto error;
 
+	ret = -ENOMEM;
+	scb = kcalloc(2, sizeof(struct afs_status_cb), GFP_KERNEL);
+	if (!scb)
+		goto error;
+
 	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);
-		goto error;
+		goto error_scb;
 	}
 
 	ret = -ERESTARTSYS;
 	if (afs_begin_vnode_operation(&fc, dvnode, key, true)) {
+		afs_dataversion_t data_version = dvnode->status.data_version + 1;
+
 		while (afs_select_fileserver(&fc)) {
 			fc.cb_break = afs_calc_vnode_cb_break(dvnode);
-			afs_fs_symlink(&fc, dentry->d_name.name,
-				       content, data_version,
-				       &newfid, &newstatus);
+			afs_prep_for_new_inode(&fc, &iget_data);
+			afs_fs_symlink(&fc, dentry->d_name.name, content,
+				       &scb[0], &iget_data.fid, &scb[1]);
 		}
 
-		afs_check_for_remote_deletion(&fc, fc.vnode);
-		afs_vnode_commit_status(&fc, dvnode, fc.cb_break);
-		afs_vnode_new_inode(&fc, dentry, &newfid, &newstatus, NULL);
+		afs_check_for_remote_deletion(&fc, dvnode);
+		afs_vnode_commit_status(&fc, dvnode, fc.cb_break,
+					&data_version, &scb[0]);
+		afs_vnode_new