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, 648 insertions, 0 deletions

diff --git a/fs/afs/dir_edit.c b/fs/afs/dir_edit.c
new file mode 100644
index 000000000..3ead36a07
--- /dev/null
+++ b/fs/afs/dir_edit.c
@@ -0,0 +1,648 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AFS filesystem directory editing
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/pagemap.h>
+#include <linux/iversion.h>
+#include <linux/folio_queue.h>
+#include "internal.h"
+#include "xdr_fs.h"
+
+/*
+ * Find a number of contiguous clear bits in a directory block bitmask.
+ *
+ * There are 64 slots, which means we can load the entire bitmap into a
+ * variable.  The first bit doesn't count as it corresponds to the block header
+ * slot.  nr_slots is between 1 and 9.
+ */
+static int afs_find_contig_bits(union afs_xdr_dir_block *block, unsigned int nr_slots)
+{
+	u64 bitmap;
+	u32 mask;
+	int bit, n;
+
+	bitmap  = (u64)block->hdr.bitmap[0] << 0 * 8;
+	bitmap |= (u64)block->hdr.bitmap[1] << 1 * 8;
+	bitmap |= (u64)block->hdr.bitmap[2] << 2 * 8;
+	bitmap |= (u64)block->hdr.bitmap[3] << 3 * 8;
+	bitmap |= (u64)block->hdr.bitmap[4] << 4 * 8;
+	bitmap |= (u64)block->hdr.bitmap[5] << 5 * 8;
+	bitmap |= (u64)block->hdr.bitmap[6] << 6 * 8;
+	bitmap |= (u64)block->hdr.bitmap[7] << 7 * 8;
+	bitmap >>= 1; /* The first entry is metadata */
+	bit = 1;
+	mask = (1 << nr_slots) - 1;
+
+	do {
+		if (sizeof(unsigned long) == 8)
+			n = ffz(bitmap);
+		else
+			n = ((u32)bitmap) != 0 ?
+				ffz((u32)bitmap) :
+				ffz((u32)(bitmap >> 32)) + 32;
+		bitmap >>= n;
+		bit += n;
+
+		if ((bitmap & mask) == 0) {
+			if (bit > 64 - nr_slots)
+				return -1;
+			return bit;
+		}
+
+		n = __ffs(bitmap);
+		bitmap >>= n;
+		bit += n;
+	} while (bitmap);
+
+	return -1;
+}
+
+/*
+ * Set a number of contiguous bits in the directory block bitmap.
+ */
+static void afs_set_contig_bits(union afs_xdr_dir_block *block,
+				int bit, unsigned int nr_slots)
+{
+	u64 mask;
+
+	mask = (1 << nr_slots) - 1;
+	mask <<= bit;
+
+	block->hdr.bitmap[0] |= (u8)(mask >> 0 * 8);
+	block->hdr.bitmap[1] |= (u8)(mask >> 1 * 8);
+	block->hdr.bitmap[2] |= (u8)(mask >> 2 * 8);
+	block->hdr.bitmap[3] |= (u8)(mask >> 3 * 8);
+	block->hdr.bitmap[4] |= (u8)(mask >> 4 * 8);
+	block->hdr.bitmap[5] |= (u8)(mask >> 5 * 8);
+	block->hdr.bitmap[6] |= (u8)(mask >> 6 * 8);
+	block->hdr.bitmap[7] |= (u8)(mask >> 7 * 8);
+}
+
+/*
+ * Clear a number of contiguous bits in the directory block bitmap.
+ */
+static void afs_clear_contig_bits(union afs_xdr_dir_block *block,
+				  int bit, unsigned int nr_slots)
+{
+	u64 mask;
+
+	mask = (1 << nr_slots) - 1;
+	mask <<= bit;
+
+	block->hdr.bitmap[0] &= ~(u8)(mask >> 0 * 8);
+	block->hdr.bitmap[1] &= ~(u8)(mask >> 1 * 8);
+	block->hdr.bitmap[2] &= ~(u8)(mask >> 2 * 8);
+	block->hdr.bitmap[3] &= ~(u8)(mask >> 3 * 8);
+	block->hdr.bitmap[4] &= ~(u8)(mask >> 4 * 8);
+	block->hdr.bitmap[5] &= ~(u8)(mask >> 5 * 8);
+	block->hdr.bitmap[6] &= ~(u8)(mask >> 6 * 8);
+	block->hdr.bitmap[7] &= ~(u8)(mask >> 7 * 8);
+}
+
+/*
+ * Get a specific block, extending the directory storage to cover it as needed.
+ */
+static union afs_xdr_dir_block *afs_dir_get_block(struct afs_dir_iter *iter, size_t block)
+{
+	struct folio_queue *fq;
+	struct afs_vnode *dvnode = iter->dvnode;
+	struct folio *folio;
+	size_t blpos = block * AFS_DIR_BLOCK_SIZE;
+	size_t blend = (block + 1) * AFS_DIR_BLOCK_SIZE, fpos = iter->fpos;
+	int ret;
+
+	if (dvnode->directory_size < blend) {
+		size_t cur_size = dvnode->directory_size;
+
+		ret = netfs_alloc_folioq_buffer(
+			NULL, &dvnode->directory, &cur_size, blend,
+			mapping_gfp_mask(dvnode->netfs.inode.i_mapping));
+		dvnode->directory_size = cur_size;
+		if (ret < 0)
+			goto fail;
+	}
+
+	fq = iter->fq;
+	if (!fq)
+		fq = dvnode->directory;
+
+	/* Search the folio queue for the folio containing the block... */
+	for (; fq; fq = fq->next) {
+		for (int s = iter->fq_slot; s < folioq_count(fq); s++) {
+			size_t fsize = folioq_folio_size(fq, s);
+
+			if (blend <= fpos + fsize) {
+				/* ... and then return the mapped block. */
+				folio = folioq_folio(fq, s);
+				if (WARN_ON_ONCE(folio_pos(folio) != fpos))
+					goto fail;
+				iter->fq = fq;
+				iter->fq_slot = s;
+				iter->fpos = fpos;
+				return kmap_local_folio(folio, blpos - fpos);
+			}
+			fpos += fsize;
+		}
+		iter->fq_slot = 0;
+	}
+
+fail:
+	iter->fq = NULL;
+	iter->fq_slot = 0;
+	afs_invalidate_dir(dvnode, afs_dir_invalid_edit_get_block);
+	return NULL;
+}
+
+/*
+ * Scan a directory block looking for a dirent of the right name.
+ */
+static int afs_dir_scan_block(const union afs_xdr_dir_block *block, const struct qstr *name,
+			      unsigned int blocknum)
+{
+	const union afs_xdr_dirent *de;
+	u64 bitmap;
+	int d, len, n;
+
+	_enter("");
+
+	bitmap  = (u64)block->hdr.bitmap[0] << 0 * 8;
+	bitmap |= (u64)block->hdr.bitmap[1] << 1 * 8;
+	bitmap |= (u64)block->hdr.bitmap[2] << 2 * 8;
+	bitmap |= (u64)block->hdr.bitmap[3] << 3 * 8;
+	bitmap |= (u64)block->hdr.bitmap[4] << 4 * 8;
+	bitmap |= (u64)block->hdr.bitmap[5] << 5 * 8;
+	bitmap |= (u64)block->hdr.bitmap[6] << 6 * 8;
+	bitmap |= (u64)block->hdr.bitmap[7] << 7 * 8;
+
+	for (d = (blocknum == 0 ? AFS_DIR_RESV_BLOCKS0 : AFS_DIR_RESV_BLOCKS);
+	     d < AFS_DIR_SLOTS_PER_BLOCK;
+	     d++) {
+		if (!((bitmap >> d) & 1))
+			continue;
+		de = &block->dirents[d];
+		if (de->u.valid != 1)
+			continue;
+
+		/* The block was NUL-terminated by afs_dir_check_page(). */
+		len = strlen(de->u.name);
+		if (len == name->len &&
+		    memcmp(de->u.name, name->name, name->len) == 0)
+			return d;
+
+		n = round_up(12 + len + 1 + 4, AFS_DIR_DIRENT_SIZE);
+		n /= AFS_DIR_DIRENT_SIZE;
+		d += n - 1;
+	}
+
+	return -1;
+}
+
+/*
+ * Initialise a new directory block.  Note that block 0 is special and contains
+ * some extra metadata.
+ */
+static void afs_edit_init_block(union afs_xdr_dir_block *meta,
+				union afs_xdr_dir_block *block, int block_num)
+{
+	memset(block, 0, sizeof(*block));
+	block->hdr.npages = htons(1);
+	block->hdr.magic = AFS_DIR_MAGIC;
+	block->hdr.bitmap[0] = 1;
+
+	if (block_num == 0) {
+		block->hdr.bitmap[0] = 0xff;
+		block->hdr.bitmap[1] = 0x1f;
+		memset(block->meta.alloc_ctrs,
+		       AFS_DIR_SLOTS_PER_BLOCK,
+		       sizeof(block->meta.alloc_ctrs));
+		meta->meta.alloc_ctrs[0] =
+			AFS_DIR_SLOTS_PER_BLOCK - AFS_DIR_RESV_BLOCKS0;
+	}
+
+	if (block_num < AFS_DIR_BLOCKS_WITH_CTR)
+		meta->meta.alloc_ctrs[block_num] =
+			AFS_DIR_SLOTS_PER_BLOCK - AFS_DIR_RESV_BLOCKS;
+}
+
+/*
+ * Edit a directory's file data to add a new directory entry.  Doing this after
+ * create, mkdir, symlink, link or rename if the data version number is
+ * incremented by exactly one avoids the need to re-download the entire
+ * directory contents.
+ *
+ * The caller must hold the inode locked.
+ */
+void afs_edit_dir_add(struct afs_vnode *vnode,
+		      const struct qstr *name, struct afs_fid *new_fid,
+		      enum afs_edit_dir_reason why)
+{
+	union afs_xdr_dir_block *meta, *block;
+	union afs_xdr_dirent *de;
+	struct afs_dir_iter iter = { .dvnode = vnode };
+	unsigned int nr_blocks, b, entry;
+	loff_t i_size;
+	int slot;
+
+	_enter(",,{%d,%s},", name->len, name->name);
+
+	i_size = i_size_read(&vnode->netfs.inode);
+	if (i_size > AFS_DIR_BLOCK_SIZE * AFS_DIR_MAX_BLOCKS ||
+	    (i_size & (AFS_DIR_BLOCK_SIZE - 1))) {
+		afs_invalidate_dir(vnode, afs_dir_invalid_edit_add_bad_size);
+		return;
+	}
+
+	meta = afs_dir_get_block(&iter, 0);
+	if (!meta)
+		return;
+
+	/* Work out how many slots we're going to need. */
+	iter.nr_slots = afs_dir_calc_slots(name->len);
+
+	if (i_size == 0)
+		goto new_directory;
+	nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
+
+	/* Find a block that has sufficient slots available.  Each folio
+	 * contains two or more directory blocks.
+	 */
+	for (b = 0; b < nr_blocks + 1; b++) {
+		/* If the directory extended into a new folio, then we need to
+		 * tack a new folio on the end.
+		 */
+		if (nr_blocks >= AFS_DIR_MAX_BLOCKS)
+			goto error_too_many_blocks;
+
+		/* Lower dir blocks have a counter in the header we can check. */
+		if (b < AFS_DIR_BLOCKS_WITH_CTR &&
+		    meta->meta.alloc_ctrs[b] < iter.nr_slots)
+			continue;
+
+		block = afs_dir_get_block(&iter, b);
+		if (!block)
+			goto error;
+
+		/* Abandon the edit if we got a callback break. */
+		if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
+			goto already_invalidated;
+
+		_debug("block %u: %2u %3u %u",
+		       b,
+		       (b < AFS_DIR_BLOCKS_WITH_CTR) ? meta->meta.alloc_ctrs[b] : 99,
+		       ntohs(block->hdr.npages),
+		       ntohs(block->hdr.magic));
+
+		/* Initialise the block if necessary. */
+		if (b == nr_blocks) {
+			_debug("init %u", b);
+			afs_edit_init_block(meta, block, b);
+			afs_set_i_size(vnode, (b + 1) * AFS_DIR_BLOCK_SIZE);
+		}
+
+		/* We need to try and find one or more consecutive slots to
+		 * hold the entry.
+		 */
+		slot = afs_find_contig_bits(block, iter.nr_slots);
+		if (slot >= 0) {
+			_debug("slot %u", slot);
+			goto found_space;
+		}
+
+		kunmap_local(block);
+	}
+
+	/* There are no spare slots of sufficient size, yet the operation
+	 * succeeded.  Download the directory again.
+	 */
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_create_nospc, 0, 0, 0, 0, name->name);
+	afs_invalidate_dir(vnode, afs_dir_invalid_edit_add_no_slots);
+	goto out_unmap;
+
+new_directory:
+	afs_edit_init_block(meta, meta, 0);
+	i_size = AFS_DIR_BLOCK_SIZE;
+	afs_set_i_size(vnode, i_size);
+	slot = AFS_DIR_RESV_BLOCKS0;
+	block = afs_dir_get_block(&iter, 0);
+	nr_blocks = 1;
+	b = 0;
+
+found_space:
+	/* Set the dirent slot. */
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_create, b, slot,
+			   new_fid->vnode, new_fid->unique, name->name);
+	de = &block->dirents[slot];
+	de->u.valid	= 1;
+	de->u.unused[0]	= 0;
+	de->u.hash_next	= 0; // TODO: Really need to maintain this
+	de->u.vnode	= htonl(new_fid->vnode);
+	de->u.unique	= htonl(new_fid->unique);
+	memcpy(de->u.name, name->name, name->len + 1);
+	de->u.name[name->len] = 0;
+
+	/* Adjust the bitmap. */
+	afs_set_contig_bits(block, slot, iter.nr_slots);
+
+	/* Adjust the allocation counter. */
+	if (b < AFS_DIR_BLOCKS_WITH_CTR)
+		meta->meta.alloc_ctrs[b] -= iter.nr_slots;
+
+	/* Adjust the hash chain. */
+	entry = b * AFS_DIR_SLOTS_PER_BLOCK + slot;
+	iter.bucket = afs_dir_hash_name(name);
+	de->u.hash_next = meta->meta.hashtable[iter.bucket];
+	meta->meta.hashtable[iter.bucket] = htons(entry);
+	kunmap_local(block);
+
+	inode_inc_iversion_raw(&vnode->netfs.inode);
+	afs_stat_v(vnode, n_dir_cr);
+	_debug("Insert %s in %u[%u]", name->name, b, slot);
+
+	netfs_single_mark_inode_dirty(&vnode->netfs.inode);
+
+out_unmap:
+	kunmap_local(meta);
+	_leave("");
+	return;
+
+already_invalidated:
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_create_inval, 0, 0, 0, 0, name->name);
+	kunmap_local(block);
+	goto out_unmap;
+
+error_too_many_blocks:
+	afs_invalidate_dir(vnode, afs_dir_invalid_edit_add_too_many_blocks);
+error:
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_create_error, 0, 0, 0, 0, name->name);
+	goto out_unmap;
+}
+
+/*
+ * Edit a directory's file data to remove a new directory entry.  Doing this
+ * after unlink, rmdir or rename if the data version number is incremented by
+ * exactly one avoids the need to re-download the entire directory contents.
+ *
+ * The caller must hold the inode locked.
+ */
+void afs_edit_dir_remove(struct afs_vnode *vnode,
+			 const struct qstr *name, enum afs_edit_dir_reason why)
+{
+	union afs_xdr_dir_block *meta, *block, *pblock;
+	union afs_xdr_dirent *de, *pde;
+	struct afs_dir_iter iter = { .dvnode = vnode };
+	struct afs_fid fid;
+	unsigned int b, slot, entry;
+	loff_t i_size;
+	__be16 next;
+	int found;
+
+	_enter(",,{%d,%s},", name->len, name->name);
+
+	i_size = i_size_read(&vnode->netfs.inode);
+	if (i_size < AFS_DIR_BLOCK_SIZE ||
+	    i_size > AFS_DIR_BLOCK_SIZE * AFS_DIR_MAX_BLOCKS ||
+	    (i_size & (AFS_DIR_BLOCK_SIZE - 1))) {
+		afs_invalidate_dir(vnode, afs_dir_invalid_edit_rem_bad_size);
+		return;
+	}
+
+	if (!afs_dir_init_iter(&iter, name))
+		return;
+
+	meta = afs_dir_get_block(&iter, 0);
+	if (!meta)
+		return;
+
+	/* Find the entry in the blob. */
+	found = afs_dir_search_bucket(&iter, name, &fid);
+	if (found < 0) {
+		/* Didn't find the dirent to clobber.  Re-download. */
+		trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_noent,
+				   0, 0, 0, 0, name->name);
+		afs_invalidate_dir(vnode, afs_dir_invalid_edit_rem_wrong_name);
+		goto out_unmap;
+	}
+
+	entry = found;
+	b    = entry / AFS_DIR_SLOTS_PER_BLOCK;
+	slot = entry % AFS_DIR_SLOTS_PER_BLOCK;
+
+	block = afs_dir_find_block(&iter, b);
+	if (!block)
+		goto error;
+	if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
+		goto already_invalidated;
+
+	/* Check and clear the entry. */
+	de = &block->dirents[slot];
+	if (de->u.valid != 1)
+		goto error_unmap;
+
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_delete, b, slot,
+			   ntohl(de->u.vnode), ntohl(de->u.unique),
+			   name->name);
+
+	/* Adjust the bitmap. */
+	afs_clear_contig_bits(block, slot, iter.nr_slots);
+
+	/* Adjust the allocation counter. */
+	if (b < AFS_DIR_BLOCKS_WITH_CTR)
+		meta->meta.alloc_ctrs[b] += iter.nr_slots;
+
+	/* Clear the constituent entries. */
+	next = de->u.hash_next;
+	memset(de, 0, sizeof(*de) * iter.nr_slots);
+	kunmap_local(block);
+
+	/* Adjust the hash chain: if iter->prev_entry is 0, the hashtable head
+	 * index is previous; otherwise it's slot number of the previous entry.
+	 */
+	if (!iter.prev_entry) {
+		__be16 prev_next = meta->meta.hashtable[iter.bucket];
+
+		if (unlikely(prev_next != htons(entry))) {
+			pr_warn("%llx:%llx:%x: not head of chain b=%x p=%x,%x e=%x %*s",
+				vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
+				iter.bucket, iter.prev_entry, prev_next, entry,
+				name->len, name->name);
+			goto error;
+		}
+		meta->meta.hashtable[iter.bucket] = next;
+	} else {
+		unsigned int pb = iter.prev_entry / AFS_DIR_SLOTS_PER_BLOCK;
+		unsigned int ps = iter.prev_entry % AFS_DIR_SLOTS_PER_BLOCK;
+		__be16 prev_next;
+
+		pblock = afs_dir_find_block(&iter, pb);
+		if (!pblock)
+			goto error;
+		pde = &pblock->dirents[ps];
+		prev_next = pde->u.hash_next;
+		if (prev_next != htons(entry)) {
+			kunmap_local(pblock);
+			pr_warn("%llx:%llx:%x: not prev in chain b=%x p=%x,%x e=%x %*s",
+				vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique,
+				iter.bucket, iter.prev_entry, prev_next, entry,
+				name->len, name->name);
+			goto error;
+		}
+		pde->u.hash_next = next;
+		kunmap_local(pblock);
+	}
+
+	netfs_single_mark_inode_dirty(&vnode->netfs.inode);
+
+	inode_set_iversion_raw(&vnode->netfs.inode, vnode->status.data_version);
+	afs_stat_v(vnode, n_dir_rm);
+	_debug("Remove %s from %u[%u]", name->name, b, slot);
+
+out_unmap:
+	kunmap_local(meta);
+	_leave("");
+	return;
+
+already_invalidated:
+	kunmap_local(block);
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_inval,
+			   0, 0, 0, 0, name->name);
+	goto out_unmap;
+
+error_unmap:
+	kunmap_local(block);
+error:
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_error,
+			   0, 0, 0, 0, name->name);
+	goto out_unmap;
+}
+
+/*
+ * Edit an entry in a directory to update the vnode it refers to.  This is also
+ * used to update the ".." entry in a directory.
+ */
+void afs_edit_dir_update(struct afs_vnode *vnode, const struct qstr *name,
+			 struct afs_vnode *new_dvnode, enum afs_edit_dir_reason why)
+{
+	union afs_xdr_dir_block *block;
+	union afs_xdr_dirent *de;
+	struct afs_dir_iter iter = { .dvnode = vnode };
+	unsigned int nr_blocks, b;
+	loff_t i_size;
+	int slot;
+
+	_enter("");
+
+	i_size = i_size_read(&vnode->netfs.inode);
+	if (i_size < AFS_DIR_BLOCK_SIZE) {
+		afs_invalidate_dir(vnode, afs_dir_invalid_edit_upd_bad_size);
+		return;
+	}
+
+	nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
+
+	/* Find a block that has sufficient slots available.  Each folio
+	 * contains two or more directory blocks.
+	 */
+	for (b = 0; b < nr_blocks; b++) {
+		block = afs_dir_get_block(&iter, b);
+		if (!block)
+			goto error;
+
+		/* Abandon the edit if we got a callback break. */
+		if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
+			goto already_invalidated;
+
+		slot = afs_dir_scan_block(block, name, b);
+		if (slot >= 0)
+			goto found_dirent;
+
+		kunmap_local(block);
+	}
+
+	/* Didn't find the dirent to clobber.  Download the directory again. */
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_update_nodd,
+			   0, 0, 0, 0, name->name);
+	afs_invalidate_dir(vnode, afs_dir_invalid_edit_upd_no_dd);
+	goto out;
+
+found_dirent:
+	de = &block->dirents[slot];
+	de->u.vnode  = htonl(new_dvnode->fid.vnode);
+	de->u.unique = htonl(new_dvnode->fid.unique);
+
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_update_dd, b, slot,
+			   ntohl(de->u.vnode), ntohl(de->u.unique), name->name);
+
+	kunmap_local(block);
+	netfs_single_mark_inode_dirty(&vnode->netfs.inode);
+	inode_set_iversion_raw(&vnode->netfs.inode, vnode->status.data_version);
+
+out:
+	_leave("");
+	return;
+
+already_invalidated:
+	kunmap_local(block);
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_update_inval,
+			   0, 0, 0, 0, name->name);
+	goto out;
+
+error:
+	trace_afs_edit_dir(vnode, why, afs_edit_dir_update_error,
+			   0, 0, 0, 0, name->name);
+	goto out;
+}
+
+/*
+ * Initialise a new directory.  We need to fill in the "." and ".." entries.
+ */
+void afs_mkdir_init_dir(struct afs_vnode *dvnode, struct afs_vnode *parent_dvnode)
+{
+	union afs_xdr_dir_block *meta;
+	struct afs_dir_iter iter = { .dvnode = dvnode };
+	union afs_xdr_dirent *de;
+	unsigned int slot = AFS_DIR_RESV_BLOCKS0;
+	loff_t i_size;
+
+	i_size = i_size_read(&dvnode->netfs.inode);
+	if (i_size != AFS_DIR_BLOCK_SIZE) {
+		afs_invalidate_dir(dvnode, afs_dir_invalid_edit_add_bad_size);
+		return;
+	}
+
+	meta = afs_dir_get_block(&iter, 0);
+	if (!meta)
+		return;
+
+	afs_edit_init_block(meta, meta, 0);
+
+	de = &meta->dirents[slot];
+	de->u.valid  = 1;
+	de->u.vnode  = htonl(dvnode->fid.vnode);
+	de->u.unique = htonl(dvnode->fid.unique);
+	memcpy(de->u.name, ".", 2);
+	trace_afs_edit_dir(dvnode, afs_edit_dir_for_mkdir, afs_edit_dir_mkdir, 0, slot,
+			   dvnode->fid.vnode, dvnode->fid.unique, ".");
+	slot++;
+
+	de = &meta->dirents[slot];
+	de->u.valid  = 1;
+	de->u.vnode  = htonl(parent_dvnode->fid.vnode);
+	de->u.unique = htonl(parent_dvnode->fid.unique);
+	memcpy(de->u.name, "..", 3);
+	trace_afs_edit_dir(dvnode, afs_edit_dir_for_mkdir, afs_edit_dir_mkdir, 0, slot,
+			   parent_dvnode->fid.vnode, parent_dvnode->fid.unique, "..");
+
+	afs_set_contig_bits(meta, AFS_DIR_RESV_BLOCKS0, 2);
+	meta->meta.alloc_ctrs[0] -= 2;
+	kunmap_local(meta);
+
+	netfs_single_mark_inode_dirty(&dvnode->netfs.inode);
+	set_bit(AFS_VNODE_DIR_VALID, &dvnode->flags);
+	set_bit(AFS_VNODE_DIR_READ, &dvnode->flags);
+}