v4.19.13 snapshot.
diff --git a/fs/afs/dir_edit.c b/fs/afs/dir_edit.c
new file mode 100644
index 0000000..8b400f5
--- /dev/null
+++ b/fs/afs/dir_edit.c
@@ -0,0 +1,505 @@
+/* AFS filesystem directory editing
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/pagemap.h>
+#include <linux/iversion.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, before, after;
+
+ mask = (1 << nr_slots) - 1;
+ mask <<= bit;
+
+ before = *(u64 *)block->hdr.bitmap;
+
+ 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);
+
+ after = *(u64 *)block->hdr.bitmap;
+}
+
+/*
+ * 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, before, after;
+
+ mask = (1 << nr_slots) - 1;
+ mask <<= bit;
+
+ before = *(u64 *)block->hdr.bitmap;
+
+ 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);
+
+ after = *(u64 *)block->hdr.bitmap;
+}
+
+/*
+ * Scan a directory block looking for a dirent of the right name.
+ */
+static int afs_dir_scan_block(union afs_xdr_dir_block *block, struct qstr *name,
+ unsigned int blocknum)
+{
+ 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,
+ struct qstr *name, struct afs_fid *new_fid,
+ enum afs_edit_dir_reason why)
+{
+ union afs_xdr_dir_block *meta, *block;
+ struct afs_xdr_dir_page *meta_page, *dir_page;
+ union afs_xdr_dirent *de;
+ struct page *page0, *page;
+ unsigned int need_slots, nr_blocks, b;
+ pgoff_t index;
+ loff_t i_size;
+ gfp_t gfp;
+ int slot;
+
+ _enter(",,{%d,%s},", name->len, name->name);
+
+ i_size = i_size_read(&vnode->vfs_inode);
+ if (i_size > AFS_DIR_BLOCK_SIZE * AFS_DIR_MAX_BLOCKS ||
+ (i_size & (AFS_DIR_BLOCK_SIZE - 1))) {
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ return;
+ }
+
+ gfp = vnode->vfs_inode.i_mapping->gfp_mask;
+ page0 = find_or_create_page(vnode->vfs_inode.i_mapping, 0, gfp);
+ if (!page0) {
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ _leave(" [fgp]");
+ return;
+ }
+
+ /* Work out how many slots we're going to need. */
+ need_slots = round_up(12 + name->len + 1 + 4, AFS_DIR_DIRENT_SIZE);
+ need_slots /= AFS_DIR_DIRENT_SIZE;
+
+ meta_page = kmap(page0);
+ meta = &meta_page->blocks[0];
+ if (i_size == 0)
+ goto new_directory;
+ nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
+
+ /* Find a block that has sufficient slots available. Each VM page
+ * contains two or more directory blocks.
+ */
+ for (b = 0; b < nr_blocks + 1; b++) {
+ /* If the directory extended into a new page, then we need to
+ * tack a new page on the end.
+ */
+ index = b / AFS_DIR_BLOCKS_PER_PAGE;
+ if (index == 0) {
+ page = page0;
+ dir_page = meta_page;
+ } else {
+ if (nr_blocks >= AFS_DIR_MAX_BLOCKS)
+ goto error;
+ gfp = vnode->vfs_inode.i_mapping->gfp_mask;
+ page = find_or_create_page(vnode->vfs_inode.i_mapping,
+ index, gfp);
+ if (!page)
+ goto error;
+ if (!PagePrivate(page)) {
+ set_page_private(page, 1);
+ SetPagePrivate(page);
+ }
+ dir_page = kmap(page);
+ }
+
+ /* Abandon the edit if we got a callback break. */
+ if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
+ goto invalidated;
+
+ block = &dir_page->blocks[b % AFS_DIR_BLOCKS_PER_PAGE];
+
+ _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);
+ i_size_write(&vnode->vfs_inode, (b + 1) * AFS_DIR_BLOCK_SIZE);
+ }
+
+ /* Only lower dir pages have a counter in the header. */
+ if (b >= AFS_DIR_BLOCKS_WITH_CTR ||
+ meta->meta.alloc_ctrs[b] >= need_slots) {
+ /* We need to try and find one or more consecutive
+ * slots to hold the entry.
+ */
+ slot = afs_find_contig_bits(block, need_slots);
+ if (slot >= 0) {
+ _debug("slot %u", slot);
+ goto found_space;
+ }
+ }
+
+ if (page != page0) {
+ unlock_page(page);
+ kunmap(page);
+ put_page(page);
+ }
+ }
+
+ /* 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);
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ goto out_unmap;
+
+new_directory:
+ afs_edit_init_block(meta, meta, 0);
+ i_size = AFS_DIR_BLOCK_SIZE;
+ i_size_write(&vnode->vfs_inode, i_size);
+ slot = AFS_DIR_RESV_BLOCKS0;
+ page = page0;
+ block = meta;
+ 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, need_slots);
+ if (page != page0) {
+ unlock_page(page);
+ kunmap(page);
+ put_page(page);
+ }
+
+ /* Adjust the allocation counter. */
+ if (b < AFS_DIR_BLOCKS_WITH_CTR)
+ meta->meta.alloc_ctrs[b] -= need_slots;
+
+ inode_inc_iversion_raw(&vnode->vfs_inode);
+ afs_stat_v(vnode, n_dir_cr);
+ _debug("Insert %s in %u[%u]", name->name, b, slot);
+
+out_unmap:
+ unlock_page(page0);
+ kunmap(page0);
+ put_page(page0);
+ _leave("");
+ return;
+
+invalidated:
+ trace_afs_edit_dir(vnode, why, afs_edit_dir_create_inval, 0, 0, 0, 0, name->name);
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ if (page != page0) {
+ kunmap(page);
+ put_page(page);
+ }
+ goto out_unmap;
+
+error:
+ trace_afs_edit_dir(vnode, why, afs_edit_dir_create_error, 0, 0, 0, 0, name->name);
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ 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,
+ struct qstr *name, enum afs_edit_dir_reason why)
+{
+ struct afs_xdr_dir_page *meta_page, *dir_page;
+ union afs_xdr_dir_block *meta, *block;
+ union afs_xdr_dirent *de;
+ struct page *page0, *page;
+ unsigned int need_slots, nr_blocks, b;
+ pgoff_t index;
+ loff_t i_size;
+ int slot;
+
+ _enter(",,{%d,%s},", name->len, name->name);
+
+ i_size = i_size_read(&vnode->vfs_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))) {
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ return;
+ }
+ nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
+
+ page0 = find_lock_page(vnode->vfs_inode.i_mapping, 0);
+ if (!page0) {
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ _leave(" [fgp]");
+ return;
+ }
+
+ /* Work out how many slots we're going to discard. */
+ need_slots = round_up(12 + name->len + 1 + 4, AFS_DIR_DIRENT_SIZE);
+ need_slots /= AFS_DIR_DIRENT_SIZE;
+
+ meta_page = kmap(page0);
+ meta = &meta_page->blocks[0];
+
+ /* Find a page that has sufficient slots available. Each VM page
+ * contains two or more directory blocks.
+ */
+ for (b = 0; b < nr_blocks; b++) {
+ index = b / AFS_DIR_BLOCKS_PER_PAGE;
+ if (index != 0) {
+ page = find_lock_page(vnode->vfs_inode.i_mapping, index);
+ if (!page)
+ goto error;
+ dir_page = kmap(page);
+ } else {
+ page = page0;
+ dir_page = meta_page;
+ }
+
+ /* Abandon the edit if we got a callback break. */
+ if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
+ goto invalidated;
+
+ block = &dir_page->blocks[b % AFS_DIR_BLOCKS_PER_PAGE];
+
+ if (b > AFS_DIR_BLOCKS_WITH_CTR ||
+ meta->meta.alloc_ctrs[b] <= AFS_DIR_SLOTS_PER_BLOCK - 1 - need_slots) {
+ slot = afs_dir_scan_block(block, name, b);
+ if (slot >= 0)
+ goto found_dirent;
+ }
+
+ if (page != page0) {
+ unlock_page(page);
+ kunmap(page);
+ put_page(page);
+ }
+ }
+
+ /* Didn't find the dirent to clobber. Download the directory again. */
+ trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_noent,
+ 0, 0, 0, 0, name->name);
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ goto out_unmap;
+
+found_dirent:
+ de = &block->dirents[slot];
+
+ trace_afs_edit_dir(vnode, why, afs_edit_dir_delete, b, slot,
+ ntohl(de->u.vnode), ntohl(de->u.unique),
+ name->name);
+
+ memset(de, 0, sizeof(*de) * need_slots);
+
+ /* Adjust the bitmap. */
+ afs_clear_contig_bits(block, slot, need_slots);
+ if (page != page0) {
+ unlock_page(page);
+ kunmap(page);
+ put_page(page);
+ }
+
+ /* Adjust the allocation counter. */
+ if (b < AFS_DIR_BLOCKS_WITH_CTR)
+ meta->meta.alloc_ctrs[b] += need_slots;
+
+ inode_set_iversion_raw(&vnode->vfs_inode, vnode->status.data_version);
+ afs_stat_v(vnode, n_dir_rm);
+ _debug("Remove %s from %u[%u]", name->name, b, slot);
+
+out_unmap:
+ unlock_page(page0);
+ kunmap(page0);
+ put_page(page0);
+ _leave("");
+ return;
+
+invalidated:
+ trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_inval,
+ 0, 0, 0, 0, name->name);
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ if (page != page0) {
+ unlock_page(page);
+ kunmap(page);
+ put_page(page);
+ }
+ goto out_unmap;
+
+error:
+ trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_error,
+ 0, 0, 0, 0, name->name);
+ clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+ goto out_unmap;
+}