Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[mirror_ubuntu-jammy-kernel.git] / fs / afs / dir.c

/* dir.c: AFS filesystem directory handling
 *
 * Copyright (C) 2002, 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 License
 * as published by the Free Software Foundation; either version
 * 2 of the License, 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/swap.h>
#include <linux/ctype.h>
#include <linux/sched.h>
#include <linux/task_io_accounting_ops.h>
#include "internal.h"
#include "xdr_fs.h"

static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
                                 unsigned int flags);
static int afs_dir_open(struct inode *inode, struct file *file);
static int afs_readdir(struct file *file, struct dir_context *ctx);
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
static int afs_d_delete(const struct dentry *dentry);
static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name, int nlen,
                                  loff_t fpos, u64 ino, unsigned dtype);
static int afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,
                              loff_t fpos, u64 ino, unsigned dtype);
static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
                      bool excl);
static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
static int afs_rmdir(struct inode *dir, struct dentry *dentry);
static int afs_unlink(struct inode *dir, struct dentry *dentry);
static int afs_link(struct dentry *from, struct inode *dir,
                    struct dentry *dentry);
static int afs_symlink(struct inode *dir, struct dentry *dentry,
                       const char *content);
static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
                      struct inode *new_dir, struct dentry *new_dentry,
                      unsigned int flags);
static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags);
static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
                                   unsigned int length);

static int afs_dir_set_page_dirty(struct page *page)
{
        BUG(); /* This should never happen. */
}

const struct file_operations afs_dir_file_operations = {
        .open           = afs_dir_open,
        .release        = afs_release,
        .iterate_shared = afs_readdir,
        .lock           = afs_lock,
        .llseek         = generic_file_llseek,
};

const struct inode_operations afs_dir_inode_operations = {
        .create         = afs_create,
        .lookup         = afs_lookup,
        .link           = afs_link,
        .unlink         = afs_unlink,
        .symlink        = afs_symlink,
        .mkdir          = afs_mkdir,
        .rmdir          = afs_rmdir,
        .rename         = afs_rename,
        .permission     = afs_permission,
        .getattr        = afs_getattr,
        .setattr        = afs_setattr,
        .listxattr      = afs_listxattr,
};

const struct address_space_operations afs_dir_aops = {
        .set_page_dirty = afs_dir_set_page_dirty,
        .releasepage    = afs_dir_releasepage,
        .invalidatepage = afs_dir_invalidatepage,
};

const struct dentry_operations afs_fs_dentry_operations = {
        .d_revalidate   = afs_d_revalidate,
        .d_delete       = afs_d_delete,
        .d_release      = afs_d_release,
        .d_automount    = afs_d_automount,
};

struct afs_lookup_one_cookie {
        struct dir_context      ctx;
        struct qstr             name;
        bool                    found;
        struct afs_fid          fid;
};

struct afs_lookup_cookie {
        struct dir_context      ctx;
        struct qstr             name;
        bool                    found;
        bool                    one_only;
        unsigned short          nr_fids;
        struct afs_file_status  *statuses;
        struct afs_callback     *callbacks;
        struct afs_fid          fids[50];
};

/*
 * check that a directory page is valid
 */
static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
                               loff_t i_size)
{
        struct afs_xdr_dir_page *dbuf;
        loff_t latter, off;
        int tmp, qty;

        /* Determine how many magic numbers there should be in this page, but
         * we must take care because the directory may change size under us.
         */
        off = page_offset(page);
        if (i_size <= off)
                goto checked;

        latter = i_size - off;
        if (latter >= PAGE_SIZE)
                qty = PAGE_SIZE;
        else
                qty = latter;
        qty /= sizeof(union afs_xdr_dir_block);

        /* check them */
        dbuf = kmap(page);
        for (tmp = 0; tmp < qty; tmp++) {
                if (dbuf->blocks[tmp].hdr.magic != AFS_DIR_MAGIC) {
                        printk("kAFS: %s(%lx): bad magic %d/%d is %04hx\n",
                               __func__, dvnode->vfs_inode.i_ino, tmp, qty,
                               ntohs(dbuf->blocks[tmp].hdr.magic));
                        trace_afs_dir_check_failed(dvnode, off, i_size);
                        kunmap(page);
                        trace_afs_file_error(dvnode, -EIO, afs_file_error_dir_bad_magic);
                        goto error;
                }

                /* Make sure each block is NUL terminated so we can reasonably
                 * use string functions on it.  The filenames in the page
                 * *should* be NUL-terminated anyway.
                 */
                ((u8 *)&dbuf->blocks[tmp])[AFS_DIR_BLOCK_SIZE - 1] = 0;
        }

        kunmap(page);

checked:
        afs_stat_v(dvnode, n_read_dir);
        return true;

error:
        return false;
}

/*
 * open an AFS directory file
 */
static int afs_dir_open(struct inode *inode, struct file *file)
{
        _enter("{%lu}", inode->i_ino);

        BUILD_BUG_ON(sizeof(union afs_xdr_dir_block) != 2048);
        BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);

        if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))
                return -ENOENT;

        return afs_open(inode, file);
}

/*
 * Read the directory into the pagecache in one go, scrubbing the previous
 * contents.  The list of pages is returned, pinning them so that they don't
 * get reclaimed during the iteration.
 */
static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
        __acquires(&dvnode->validate_lock)
{
        struct afs_read *req;
        loff_t i_size;
        int nr_pages, nr_inline, i, n;
        int ret = -ENOMEM;

retry:
        i_size = i_size_read(&dvnode->vfs_inode);
        if (i_size < 2048)
                return ERR_PTR(afs_bad(dvnode, afs_file_error_dir_small));
        if (i_size > 2048 * 1024) {
                trace_afs_file_error(dvnode, -EFBIG, afs_file_error_dir_big);
                return ERR_PTR(-EFBIG);
        }

        _enter("%llu", i_size);

        /* Get a request record to hold the page list.  We want to hold it
         * inline if we can, but we don't want to make an order 1 allocation.
         */
        nr_pages = (i_size + PAGE_SIZE - 1) / PAGE_SIZE;
        nr_inline = nr_pages;
        if (nr_inline > (PAGE_SIZE - sizeof(*req)) / sizeof(struct page *))
                nr_inline = 0;

        req = kzalloc(sizeof(*req) + sizeof(struct page *) * nr_inline,
                      GFP_KERNEL);
        if (!req)
                return ERR_PTR(-ENOMEM);

        refcount_set(&req->usage, 1);
        req->nr_pages = nr_pages;
        req->actual_len = i_size; /* May change */
        req->len = nr_pages * PAGE_SIZE; /* We can ask for more than there is */
        req->data_version = dvnode->status.data_version; /* May change */
        if (nr_inline > 0) {
                req->pages = req->array;
        } else {
                req->pages = kcalloc(nr_pages, sizeof(struct page *),
                                     GFP_KERNEL);
                if (!req->pages)
                        goto error;
        }

        /* Get a list of all the pages that hold or will hold the directory
         * content.  We need to fill in any gaps that we might find where the
         * memory reclaimer has been at work.  If there are any gaps, we will
         * need to reread the entire directory contents.
         */
        i = 0;
        do {
                n = find_get_pages_contig(dvnode->vfs_inode.i_mapping, i,
                                          req->nr_pages - i,
                                          req->pages + i);
                _debug("find %u at %u/%u", n, i, req->nr_pages);
                if (n == 0) {
                        gfp_t gfp = dvnode->vfs_inode.i_mapping->gfp_mask;

                        if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                                afs_stat_v(dvnode, n_inval);

                        ret = -ENOMEM;
                        req->pages[i] = __page_cache_alloc(gfp);
                        if (!req->pages[i])
                                goto error;
                        ret = add_to_page_cache_lru(req->pages[i],
                                                    dvnode->vfs_inode.i_mapping,
                                                    i, gfp);
                        if (ret < 0)
                                goto error;

                        set_page_private(req->pages[i], 1);
                        SetPagePrivate(req->pages[i]);
                        unlock_page(req->pages[i]);
                        i++;
                } else {
                        i += n;
                }
        } while (i < req->nr_pages);

        /* If we're going to reload, we need to lock all the pages to prevent
         * races.
         */
        ret = -ERESTARTSYS;
        if (down_read_killable(&dvnode->validate_lock) < 0)
                goto error;

        if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                goto success;

        up_read(&dvnode->validate_lock);
        if (down_write_killable(&dvnode->validate_lock) < 0)
                goto error;

        if (!test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) {
                ret = afs_fetch_data(dvnode, key, req);
                if (ret < 0)
                        goto error_unlock;

                task_io_account_read(PAGE_SIZE * req->nr_pages);

                if (req->len < req->file_size)
                        goto content_has_grown;

                /* Validate the data we just read. */
                ret = -EIO;
                for (i = 0; i < req->nr_pages; i++)
                        if (!afs_dir_check_page(dvnode, req->pages[i],
                                                req->actual_len))
                                goto error_unlock;

                // TODO: Trim excess pages

                set_bit(AFS_VNODE_DIR_VALID, &dvnode->flags);
        }

        downgrade_write(&dvnode->validate_lock);
success:
        return req;

error_unlock:
        up_write(&dvnode->validate_lock);
error:
        afs_put_read(req);
        _leave(" = %d", ret);
        return ERR_PTR(ret);

content_has_grown:
        up_write(&dvnode->validate_lock);
        afs_put_read(req);
        goto retry;
}

/*
 * deal with one block in an AFS directory
 */
static int afs_dir_iterate_block(struct afs_vnode *dvnode,
                                 struct dir_context *ctx,
                                 union afs_xdr_dir_block *block,
                                 unsigned blkoff)
{
        union afs_xdr_dirent *dire;
        unsigned offset, next, curr;
        size_t nlen;
        int tmp;

        _enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);

        curr = (ctx->pos - blkoff) / sizeof(union afs_xdr_dirent);

        /* walk through the block, an entry at a time */
        for (offset = (blkoff == 0 ? AFS_DIR_RESV_BLOCKS0 : AFS_DIR_RESV_BLOCKS);
             offset < AFS_DIR_SLOTS_PER_BLOCK;
             offset = next
             ) {
                next = offset + 1;

                /* skip entries marked unused in the bitmap */
                if (!(block->hdr.bitmap[offset / 8] &
                      (1 << (offset % 8)))) {
                        _debug("ENT[%zu.%u]: unused",
                               blkoff / sizeof(union afs_xdr_dir_block), offset);
                        if (offset >= curr)
                                ctx->pos = blkoff +
                                        next * sizeof(union afs_xdr_dirent);
                        continue;
                }

                /* got a valid entry */
                dire = &block->dirents[offset];
                nlen = strnlen(dire->u.name,
                               sizeof(*block) -
                               offset * sizeof(union afs_xdr_dirent));

                _debug("ENT[%zu.%u]: %s %zu \"%s\"",
                       blkoff / sizeof(union afs_xdr_dir_block), offset,
                       (offset < curr ? "skip" : "fill"),
                       nlen, dire->u.name);

                /* work out where the next possible entry is */
                for (tmp = nlen; tmp > 15; tmp -= sizeof(union afs_xdr_dirent)) {
                        if (next >= AFS_DIR_SLOTS_PER_BLOCK) {
                                _debug("ENT[%zu.%u]:"
                                       " %u travelled beyond end dir block"
                                       " (len %u/%zu)",
                                       blkoff / sizeof(union afs_xdr_dir_block),
                                       offset, next, tmp, nlen);
                                return afs_bad(dvnode, afs_file_error_dir_over_end);
                        }
                        if (!(block->hdr.bitmap[next / 8] &
                              (1 << (next % 8)))) {
                                _debug("ENT[%zu.%u]:"
                                       " %u unmarked extension (len %u/%zu)",
                                       blkoff / sizeof(union afs_xdr_dir_block),
                                       offset, next, tmp, nlen);
                                return afs_bad(dvnode, afs_file_error_dir_unmarked_ext);
                        }

                        _debug("ENT[%zu.%u]: ext %u/%zu",
                               blkoff / sizeof(union afs_xdr_dir_block),
                               next, tmp, nlen);
                        next++;
                }

                /* skip if starts before the current position */
                if (offset < curr)
                        continue;

                /* found the next entry */
                if (!dir_emit(ctx, dire->u.name, nlen,
                              ntohl(dire->u.vnode),
                              (ctx->actor == afs_lookup_filldir ||
                               ctx->actor == afs_lookup_one_filldir)?
                              ntohl(dire->u.unique) : DT_UNKNOWN)) {
                        _leave(" = 0 [full]");
                        return 0;
                }

                ctx->pos = blkoff + next * sizeof(union afs_xdr_dirent);
        }

        _leave(" = 1 [more]");
        return 1;
}

/*
 * iterate through the data blob that lists the contents of an AFS directory
 */
static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
                           struct key *key)
{
        struct afs_vnode *dvnode = AFS_FS_I(dir);
        struct afs_xdr_dir_page *dbuf;
        union afs_xdr_dir_block *dblock;
        struct afs_read *req;
        struct page *page;
        unsigned blkoff, limit;
        int ret;

        _enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);

        if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
                _leave(" = -ESTALE");
                return -ESTALE;
        }

        req = afs_read_dir(dvnode, key);
        if (IS_ERR(req))
                return PTR_ERR(req);

        /* round the file position up to the next entry boundary */
        ctx->pos += sizeof(union afs_xdr_dirent) - 1;
        ctx->pos &= ~(sizeof(union afs_xdr_dirent) - 1);

        /* walk through the blocks in sequence */
        ret = 0;
        while (ctx->pos < req->actual_len) {
                blkoff = ctx->pos & ~(sizeof(union afs_xdr_dir_block) - 1);

                /* Fetch the appropriate page from the directory and re-add it
                 * to the LRU.
                 */
                page = req->pages[blkoff / PAGE_SIZE];
                if (!page) {
                        ret = afs_bad(dvnode, afs_file_error_dir_missing_page);
                        break;
                }
                mark_page_accessed(page);

                limit = blkoff & ~(PAGE_SIZE - 1);

                dbuf = kmap(page);

                /* deal with the individual blocks stashed on this page */
                do {
                        dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
                                               sizeof(union afs_xdr_dir_block)];
                        ret = afs_dir_iterate_block(dvnode, ctx, dblock, blkoff);
                        if (ret != 1) {
                                kunmap(page);
                                goto out;
                        }

                        blkoff += sizeof(union afs_xdr_dir_block);

                } while (ctx->pos < dir->i_size && blkoff < limit);

                kunmap(page);
                ret = 0;
        }

out:
        up_read(&dvnode->validate_lock);
        afs_put_read(req);
        _leave(" = %d", ret);
        return ret;
}

/*
 * read an AFS directory
 */
static int afs_readdir(struct file *file, struct dir_context *ctx)
{
        return afs_dir_iterate(file_inode(file), ctx, afs_file_key(file));
}

/*
 * Search the directory for a single name
 * - if afs_dir_iterate_block() spots this function, it'll pass the FID
 *   uniquifier through dtype
 */
static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name,
                                  int nlen, loff_t fpos, u64 ino, unsigned dtype)
{
        struct afs_lookup_one_cookie *cookie =
                container_of(ctx, struct afs_lookup_one_cookie, ctx);

        _enter("{%s,%u},%s,%u,,%llu,%u",
               cookie->name.name, cookie->name.len, name, nlen,
               (unsigned long long) ino, dtype);

        /* insanity checks first */
        BUILD_BUG_ON(sizeof(union afs_xdr_dir_block) != 2048);
        BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);

        if (cookie->name.len != nlen ||
            memcmp(cookie->name.name, name, nlen) != 0) {
                _leave(" = 0 [no]");
                return 0;
        }

        cookie->fid.vnode = ino;
        cookie->fid.unique = dtype;
        cookie->found = 1;

        _leave(" = -1 [found]");
        return -1;
}

/*
 * Do a lookup of a single name in a directory
 * - just returns the FID the dentry name maps to if found
 */
static int afs_do_lookup_one(struct inode *dir, struct dentry *dentry,
                             struct afs_fid *fid, struct key *key)
{
        struct afs_super_info *as = dir->i_sb->s_fs_info;
        struct afs_lookup_one_cookie cookie = {
                .ctx.actor = afs_lookup_one_filldir,
                .name = dentry->d_name,
                .fid.vid = as->volume->vid
        };
        int ret;

        _enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);

        /* search the directory */
        ret = afs_dir_iterate(dir, &cookie.ctx, key);
        if (ret < 0) {
                _leave(" = %d [iter]", ret);
                return ret;
        }

        ret = -ENOENT;
        if (!cookie.found) {
                _leave(" = -ENOENT [not found]");
                return -ENOENT;
        }

        *fid = cookie.fid;
        _leave(" = 0 { vn=%llu u=%u }", fid->vnode, fid->unique);
        return 0;
}

/*
 * search the directory for a name
 * - if afs_dir_iterate_block() spots this function, it'll pass the FID
 *   uniquifier through dtype
 */
static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
                              int nlen, loff_t fpos, u64 ino, unsigned dtype)
{
        struct afs_lookup_cookie *cookie =
                container_of(ctx, struct afs_lookup_cookie, ctx);
        int ret;

        _enter("{%s,%u},%s,%u,,%llu,%u",
               cookie->name.name, cookie->name.len, name, nlen,
               (unsigned long long) ino, dtype);

        /* insanity checks first */
        BUILD_BUG_ON(sizeof(union afs_xdr_dir_block) != 2048);
        BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);

        if (cookie->found) {
                if (cookie->nr_fids < 50) {
                        cookie->fids[cookie->nr_fids].vnode     = ino;
                        cookie->fids[cookie->nr_fids].unique    = dtype;
                        cookie->nr_fids++;
                }
        } else if (cookie->name.len == nlen &&
                   memcmp(cookie->name.name, name, nlen) == 0) {
                cookie->fids[0].vnode   = ino;
                cookie->fids[0].unique  = dtype;
                cookie->found = 1;
                if (cookie->one_only)
                        return -1;
        }

        ret = cookie->nr_fids >= 50 ? -1 : 0;
        _leave(" = %d", ret);
        return ret;
}

/*
 * Do a lookup in a directory.  We make use of bulk lookup to query a slew of
 * files in one go and create inodes for them.  The inode of the file we were
 * asked for is returned.
 */
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_super_info *as = dir->i_sb->s_fs_info;
        struct afs_iget_data data;
        struct afs_fs_cursor fc;
        struct afs_vnode *dvnode = AFS_FS_I(dir);
        struct inode *inode = NULL;
        int ret, i;

        _enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);

        cookie = kzalloc(sizeof(struct afs_lookup_cookie), GFP_KERNEL);
        if (!cookie)
                return ERR_PTR(-ENOMEM);

        cookie->ctx.actor = afs_lookup_filldir;
        cookie->name = dentry->d_name;
        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;
        read_sequnlock_excl(&dvnode->cb_lock);

        for (i = 0; i < 50; i++)
                cookie->fids[i].vid = as->volume->vid;

        /* search the directory */
        ret = afs_dir_iterate(dir, &cookie->ctx, key);
        if (ret < 0) {
                inode = ERR_PTR(ret);
                goto out;
        }

        inode = ERR_PTR(-ENOENT);
        if (!cookie->found)
                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);
        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);
        if (!cookie->statuses)
                goto out;

        cookie->callbacks = kcalloc(cookie->nr_fids, sizeof(struct afs_callback),
                                    GFP_KERNEL);
        if (!cookie->callbacks)
                goto out_s;

        /* Try FS.InlineBulkStatus first.  Abort codes for the individual
         * lookups contained therein are stored in the reply without aborting
         * the whole operation.
         */
        if (cookie->one_only)
                goto no_inline_bulk_status;

        inode = ERR_PTR(-ERESTARTSYS);
        if (afs_begin_vnode_operation(&fc, dvnode, key)) {
                while (afs_select_fileserver(&fc)) {
                        if (test_bit(AFS_SERVER_FL_NO_IBULK,
                                      &fc.cbi->server->flags)) {
                                fc.ac.abort_code = RX_INVALID_OPERATION;
                                fc.ac.error = -ECONNABORTED;
                                break;
                        }
                        afs_fs_inline_bulk_status(&fc,
                                                  afs_v2net(dvnode),
                                                  cookie->fids,
                                                  cookie->statuses,
                                                  cookie->callbacks,
                                                  cookie->nr_fids, NULL);
                }

                if (fc.ac.error == 0)
                        cbi = afs_get_cb_interest(fc.cbi);
                if (fc.ac.abort_code == RX_INVALID_OPERATION)
                        set_bit(AFS_SERVER_FL_NO_IBULK, &fc.cbi->server->flags);
                inode = ERR_PTR(afs_end_vnode_operation(&fc));
        }

        if (!IS_ERR(inode))
                goto success;
        if (fc.ac.abort_code != RX_INVALID_OPERATION)
                goto out_c;

no_inline_bulk_status:
        /* We could try FS.BulkStatus next, but this aborts the entire op if
         * 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)) {
                while (afs_select_fileserver(&fc)) {
                        afs_fs_fetch_status(&fc,
                                            afs_v2net(dvnode),
                                            cookie->fids,
                                            cookie->statuses,
                                            cookie->callbacks,
                                            NULL);
                }

                if (fc.ac.error == 0)
                        cbi = afs_get_cb_interest(fc.cbi);
                inode = ERR_PTR(afs_end_vnode_operation(&fc));
        }

        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));

        for (i = 0; i < cookie->nr_fids; i++) {
                struct inode *ti;

                if (cookie->statuses[i].abort_code != 0)
                        continue;

                ti = afs_iget(dir->i_sb, key, &cookie->fids[i],
                              &cookie->statuses[i],
                              &cookie->callbacks[i],
                              cbi);
                if (i == 0) {
                        inode = ti;
                } else {
                        if (!IS_ERR(ti))
                                iput(ti);
                }
        }

out_c:
        afs_put_cb_interest(afs_v2net(dvnode), cbi);
        kfree(cookie->callbacks);
out_s:
        kfree(cookie->statuses);
out:
        kfree(cookie);
        return inode;
}

/*
 * Look up an entry in a directory with @sys substitution.
 */
static struct dentry *afs_lookup_atsys(struct inode *dir, struct dentry *dentry,
                                       struct key *key)
{
        struct afs_sysnames *subs;
        struct afs_net *net = afs_i2net(dir);
        struct dentry *ret;
        char *buf, *p, *name;
        int len, i;

        _enter("");

        ret = ERR_PTR(-ENOMEM);
        p = buf = kmalloc(AFSNAMEMAX, GFP_KERNEL);
        if (!buf)
                goto out_p;
        if (dentry->d_name.len > 4) {
                memcpy(p, dentry->d_name.name, dentry->d_name.len - 4);
                p += dentry->d_name.len - 4;
        }

        /* There is an ordered list of substitutes that we have to try. */
        read_lock(&net->sysnames_lock);
        subs = net->sysnames;
        refcount_inc(&subs->usage);
        read_unlock(&net->sysnames_lock);

        for (i = 0; i < subs->nr; i++) {
                name = subs->subs[i];
                len = dentry->d_name.len - 4 + strlen(name);
                if (len >= AFSNAMEMAX) {
                        ret = ERR_PTR(-ENAMETOOLONG);
                        goto out_s;
                }

                strcpy(p, name);
                ret = lookup_one_len(buf, dentry->d_parent, len);
                if (IS_ERR(ret) || d_is_positive(ret))
                        goto out_s;
                dput(ret);
        }

        /* We don't want to d_add() the @sys dentry here as we don't want to
         * the cached dentry to hide changes to the sysnames list.
         */
        ret = NULL;
out_s:
        afs_put_sysnames(subs);
        kfree(buf);
out_p:
        key_put(key);
        return ret;
}

/*
 * look up an entry in a directory
 */
static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
                                 unsigned int flags)
{
        struct afs_vnode *dvnode = AFS_FS_I(dir);
        struct inode *inode;
        struct dentry *d;
        struct key *key;
        int ret;

        _enter("{%llx:%llu},%p{%pd},",
               dvnode->fid.vid, dvnode->fid.vnode, dentry, dentry);

        ASSERTCMP(d_inode(dentry), ==, NULL);

        if (dentry->d_name.len >= AFSNAMEMAX) {
                _leave(" = -ENAMETOOLONG");
                return ERR_PTR(-ENAMETOOLONG);
        }

        if (test_bit(AFS_VNODE_DELETED, &dvnode->flags)) {
                _leave(" = -ESTALE");
                return ERR_PTR(-ESTALE);
        }

        key = afs_request_key(dvnode->volume->cell);
        if (IS_ERR(key)) {
                _leave(" = %ld [key]", PTR_ERR(key));
                return ERR_CAST(key);
        }

        ret = afs_validate(dvnode, key);
        if (ret < 0) {
                key_put(key);
                _leave(" = %d [val]", ret);
                return ERR_PTR(ret);
        }

        if (dentry->d_name.len >= 4 &&
            dentry->d_name.name[dentry->d_name.len - 4] == '@' &&
            dentry->d_name.name[dentry->d_name.len - 3] == 's' &&
            dentry->d_name.name[dentry->d_name.len - 2] == 'y' &&
            dentry->d_name.name[dentry->d_name.len - 1] == 's')
                return afs_lookup_atsys(dir, dentry, key);

        afs_stat_v(dvnode, n_lookup);
        inode = afs_do_lookup(dir, dentry, key);
        key_put(key);
        if (inode == ERR_PTR(-ENOENT)) {
                inode = afs_try_auto_mntpt(dentry, dir);
        } else {
                dentry->d_fsdata =
                        (void *)(unsigned long)dvnode->status.data_version;
        }
        d = d_splice_alias(inode, dentry);
        if (!IS_ERR_OR_NULL(d))
                d->d_fsdata = dentry->d_fsdata;
        return d;
}

/*
 * check that a dentry lookup hit has found a valid entry
 * - NOTE! the hit can be a negative hit too, so we can't assume we have an
 *   inode
 */
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
{
        struct afs_vnode *vnode, *dir;
        struct afs_fid uninitialized_var(fid);
        struct dentry *parent;
        struct inode *inode;
        struct key *key;
        long dir_version, de_version;
        int ret;

        if (flags & LOOKUP_RCU)
                return -ECHILD;

        if (d_really_is_positive(dentry)) {
                vnode = AFS_FS_I(d_inode(dentry));
                _enter("{v={%llx:%llu} n=%pd fl=%lx},",
                       vnode->fid.vid, vnode->fid.vnode, dentry,
                       vnode->flags);
        } else {
                _enter("{neg n=%pd}", dentry);
        }

        key = afs_request_key(AFS_FS_S(dentry->d_sb)->volume->cell);
        if (IS_ERR(key))
                key = NULL;

        if (d_really_is_positive(dentry)) {
                inode = d_inode(dentry);
                if (inode) {
                        vnode = AFS_FS_I(inode);
                        afs_validate(vnode, key);
                        if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
                                goto out_bad;
                }
        }

        /* lock down the parent dentry so we can peer at it */
        parent = dget_parent(dentry);
        dir = AFS_FS_I(d_inode(parent));

        /* validate the parent directory */
        afs_validate(dir, key);

        if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
                _debug("%pd: parent dir deleted", dentry);
                goto out_bad_parent;
        }

        /* We only need to invalidate a dentry if the server's copy changed
         * behind our back.  If we made the change, it's no problem.  Note that
         * on a 32-bit system, we only have 32 bits in the dentry to store the
         * version.
         */
        dir_version = (long)dir->status.data_version;
        de_version = (long)dentry->d_fsdata;
        if (de_version == dir_version)
                goto out_valid;

        dir_version = (long)dir->invalid_before;
        if (de_version - dir_version >= 0)
                goto out_valid;

        _debug("dir modified");
        afs_stat_v(dir, n_reval);

        /* search the directory for this vnode */
        ret = afs_do_lookup_one(&dir->vfs_inode, dentry, &fid, key);
        switch (ret) {
        case 0:
                /* the filename maps to something */
                if (d_really_is_negative(dentry))
                        goto out_bad_parent;
                inode = d_inode(dentry);
                if (is_bad_inode(inode)) {
                        printk("kAFS: afs_d_revalidate: %pd2 has bad inode\n",
                               dentry);
                        goto out_bad_parent;
                }

                vnode = AFS_FS_I(inode);

                /* if the vnode ID has changed, then the dirent points to a
                 * different file */
                if (fid.vnode != vnode->fid.vnode) {
                        _debug("%pd: dirent changed [%llu != %llu]",
                               dentry, fid.vnode,
                               vnode->fid.vnode);
                        goto not_found;
                }

                /* if the vnode ID uniqifier has changed, then the file has
                 * been deleted and replaced, and the original vnode ID has
                 * been reused */
                if (fid.unique != vnode->fid.unique) {
                        _debug("%pd: file deleted (uq %u -> %u I:%u)",
                               dentry, fid.unique,
                               vnode->fid.unique,
                               vnode->vfs_inode.i_generation);
                        write_seqlock(&vnode->cb_lock);
                        set_bit(AFS_VNODE_DELETED, &vnode->flags);
                        write_sequnlock(&vnode->cb_lock);
                        goto not_found;
                }
                goto out_valid;

        case -ENOENT:
                /* the filename is unknown */
                _debug("%pd: dirent not found", dentry);
                if (d_really_is_positive(dentry))
                        goto not_found;
                goto out_valid;

        default:
                _debug("failed to iterate dir %pd: %d",
                       parent, ret);
                goto out_bad_parent;
        }

out_valid:
        dentry->d_fsdata = (void *)dir_version;
        dput(parent);
        key_put(key);
        _leave(" = 1 [valid]");
        return 1;

        /* the dirent, if it exists, now points to a different vnode */
not_found:
        spin_lock(&dentry->d_lock);
        dentry->d_flags |= DCACHE_NFSFS_RENAMED;
        spin_unlock(&dentry->d_lock);

out_bad_parent:
        _debug("dropping dentry %pd2", dentry);
        dput(parent);
out_bad:
        key_put(key);

        _leave(" = 0 [bad]");
        return 0;
}

/*
 * allow the VFS to enquire as to whether a dentry should be unhashed (mustn't
 * sleep)
 * - called from dput() when d_count is going to 0.
 * - return 1 to request dentry be unhashed, 0 otherwise
 */
static int afs_d_delete(const struct dentry *dentry)
{
        _enter("%pd", dentry);

        if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
                goto zap;

        if (d_really_is_positive(dentry) &&
            (test_bit(AFS_VNODE_DELETED,   &AFS_FS_I(d_inode(dentry))->flags) ||
             test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(d_inode(dentry))->flags)))
                goto zap;

        _leave(" = 0 [keep]");
        return 0;

zap:
        _leave(" = 1 [zap]");
        return 1;
}

/*
 * handle dentry release
 */
void afs_d_release(struct dentry *dentry)
{
        _enter("%pd", dentry);
}

/*
 * Create a new inode for create/mkdir/symlink
 */
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_vnode *vnode;
        struct inode *inode;

        if (fc->ac.error < 0)
                return;

        inode = afs_iget(fc->vnode->vfs_inode.i_sb, fc->key,
                         newfid, newstatus, newcb, fc->cbi);
        if (IS_ERR(inode)) {
                /* ENOMEM or EINTR at a really inconvenient time - just abandon
                 * the new directory on the server.
                 */
                fc->ac.error = PTR_ERR(inode);
                return;
        }

        vnode = AFS_FS_I(inode);
        set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
        afs_vnode_commit_status(fc, vnode, 0);
        d_instantiate(new_dentry, inode);
}

/*
 * 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_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;

        _enter("{%llx:%llu},{%pd},%ho",
               dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);

        key = afs_request_key(dvnode->volume->cell);
        if (IS_ERR(key)) {
                ret = PTR_ERR(key);
                goto error;
        }

        ret = -ERESTARTSYS;
        if (afs_begin_vnode_operation(&fc, dvnode, key)) {
                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_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);
                ret = afs_end_vnode_operation(&fc);
                if (ret < 0)
                        goto error_key;
        } else {
                goto error_key;
        }

        if (ret == 0 &&
            test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                afs_edit_dir_add(dvnode, &dentry->d_name, &newfid,
                                 afs_edit_dir_for_create);

        key_put(key);
        _leave(" = 0");
        return 0;

error_key:
        key_put(key);
error:
        d_drop(dentry);
        _leave(" = %d", ret);
        return ret;
}

/*
 * Remove a subdir from a directory.
 */
static void afs_dir_remove_subdir(struct dentry *dentry)
{
        if (d_really_is_positive(dentry)) {
                struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));

                clear_nlink(&vnode->vfs_inode);
                set_bit(AFS_VNODE_DELETED, &vnode->flags);
                clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
                clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
        }
}

/*
 * remove a directory from an AFS filesystem
 */
static int afs_rmdir(struct inode *dir, struct dentry *dentry)
{
        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);

        key = afs_request_key(dvnode->volume->cell);
        if (IS_ERR(key)) {
                ret = PTR_ERR(key);
                goto error;
        }

        /* Try to make sure we have a callback promise on the victim. */
        if (d_really_is_positive(dentry)) {
                vnode = AFS_FS_I(d_inode(dentry));
                ret = afs_validate(vnode, key);
                if (ret < 0)
                        goto error_key;
        }

        ret = -ERESTARTSYS;
        if (afs_begin_vnode_operation(&fc, dvnode, key)) {
                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_vnode_commit_status(&fc, dvnode, fc.cb_break);
                ret = afs_end_vnode_operation(&fc);
                if (ret == 0) {
                        afs_dir_remove_subdir(dentry);
                        if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                                afs_edit_dir_remove(dvnode, &dentry->d_name,
                                                    afs_edit_dir_for_rmdir);
                }
        }

error_key:
        key_put(key);
error:
        return ret;
}

/*
 * Remove a link to a file or symlink from a directory.
 *
 * If the file was not deleted due to excess hard links, the fileserver will
 * break the callback promise on the file - if it had one - before it returns
 * to us, and if it was deleted, it won't
 *
 * 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...
 */
static int afs_dir_remove_link(struct dentry *dentry, struct key *key,
                               unsigned long d_version_before,
                               unsigned long d_version_after)
{
        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) {
                        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);
                        }
                        ret = 0;
                } else {
                        clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);

                        if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
                                kdebug("AFS_VNODE_DELETED");

                        ret = afs_validate(vnode, key);
                        if (ret == -ESTALE)
                                ret = 0;
                }
                _debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
        }

        return ret;
}

/*
 * Remove a file or symlink from an AFS filesystem.
 */
static int afs_unlink(struct inode *dir, struct dentry *dentry)
{
        struct afs_fs_cursor fc;
        struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode = NULL;
        struct key *key;
        unsigned long d_version = (unsigned long)dentry->d_fsdata;
        u64 data_version = dvnode->status.data_version;
        int ret;

        _enter("{%llx:%llu},{%pd}",
               dvnode->fid.vid, dvnode->fid.vnode, dentry);

        if (dentry->d_name.len >= AFSNAMEMAX)
                return -ENAMETOOLONG;

        key = afs_request_key(dvnode->volume->cell);
        if (IS_ERR(key)) {
                ret = PTR_ERR(key);
                goto error;
        }

        /* Try to make sure we have a callback promise on the victim. */
        if (d_really_is_positive(dentry)) {
                vnode = AFS_FS_I(d_inode(dentry));
                ret = afs_validate(vnode, key);
                if (ret < 0)
                        goto error_key;
        }

        ret = -ERESTARTSYS;
        if (afs_begin_vnode_operation(&fc, dvnode, key)) {
                while (afs_select_fileserver(&fc)) {
                        fc.cb_break = afs_calc_vnode_cb_break(dvnode);

                        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);
                                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_vnode_commit_status(&fc, dvnode, fc.cb_break);
                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 &&
                    test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                        afs_edit_dir_remove(dvnode, &dentry->d_name,
                                            afs_edit_dir_for_unlink);
        }

error_key:
        key_put(key);
error:
        _leave(" = %d", ret);
        return ret;
}

/*
 * create a regular file on an AFS filesystem
 */
static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
                      bool excl)
{
        struct afs_fs_cursor fc;
        struct afs_file_status newstatus;
        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_IFREG;

        _enter("{%llx:%llu},{%pd},%ho,",
               dvnode->fid.vid, dvnode->fid.vnode, dentry, mode);

        ret = -ENAMETOOLONG;
        if (dentry->d_name.len >= AFSNAMEMAX)
                goto error;

        key = afs_request_key(dvnode->volume->cell);
        if (IS_ERR(key)) {
                ret = PTR_ERR(key);
                goto error;
        }

        ret = -ERESTARTSYS;
        if (afs_begin_vnode_operation(&fc, dvnode, key)) {
                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_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);
                ret = afs_end_vnode_operation(&fc);
                if (ret < 0)
                        goto error_key;
        } else {
                goto error_key;
        }

        if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                afs_edit_dir_add(dvnode, &dentry->d_name, &newfid,
                                 afs_edit_dir_for_create);

        key_put(key);
        _leave(" = 0");
        return 0;

error_key:
        key_put(key);
error:
        d_drop(dentry);
        _leave(" = %d", ret);
        return ret;
}

/*
 * create a hard link between files in an AFS filesystem
 */
static int afs_link(struct dentry *from, struct inode *dir,
                    struct dentry *dentry)
{
        struct afs_fs_cursor fc;
        struct afs_vnode *dvnode, *vnode;
        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,
               dentry);

        ret = -ENAMETOOLONG;
        if (dentry->d_name.len >= AFSNAMEMAX)
                goto error;

        key = afs_request_key(dvnode->volume->cell);
        if (IS_ERR(key)) {
                ret = PTR_ERR(key);
                goto error;
        }

        ret = -ERESTARTSYS;
        if (afs_begin_vnode_operation(&fc, dvnode, key)) {
                if (mutex_lock_interruptible_nested(&vnode->io_lock, 1) < 0) {
                        afs_end_vnode_operation(&fc);
                        goto error_key;
                }

                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_vnode_commit_status(&fc, dvnode, fc.cb_break);
                afs_vnode_commit_status(&fc, vnode, fc.cb_break_2);
                ihold(&vnode->vfs_inode);
                d_instantiate(dentry, &vnode->vfs_inode);

                mutex_unlock(&vnode->io_lock);
                ret = afs_end_vnode_operation(&fc);
                if (ret < 0)
                        goto error_key;
        } else {
                goto error_key;
        }

        if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                afs_edit_dir_add(dvnode, &dentry->d_name, &vnode->fid,
                                 afs_edit_dir_for_link);

        key_put(key);
        _leave(" = 0");
        return 0;

error_key:
        key_put(key);
error:
        d_drop(dentry);
        _leave(" = %d", ret);
        return ret;
}

/*
 * create a symlink in an AFS filesystem
 */
static int afs_symlink(struct inode *dir, struct dentry *dentry,
                       const char *content)
{
        struct afs_fs_cursor fc;
        struct afs_file_status newstatus;
        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",
               dvnode->fid.vid, dvnode->fid.vnode, dentry,
               content);

        ret = -ENAMETOOLONG;
        if (dentry->d_name.len >= AFSNAMEMAX)
                goto error;

        ret = -EINVAL;
        if (strlen(content) >= AFSPATHMAX)
                goto error;

        key = afs_request_key(dvnode->volume->cell);
        if (IS_ERR(key)) {
                ret = PTR_ERR(key);
                goto error;
        }

        ret = -ERESTARTSYS;
        if (afs_begin_vnode_operation(&fc, dvnode, key)) {
                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_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);
                ret = afs_end_vnode_operation(&fc);
                if (ret < 0)
                        goto error_key;
        } else {
                goto error_key;
        }

        if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                afs_edit_dir_add(dvnode, &dentry->d_name, &newfid,
                                 afs_edit_dir_for_symlink);

        key_put(key);
        _leave(" = 0");
        return 0;

error_key:
        key_put(key);
error:
        d_drop(dentry);
        _leave(" = %d", ret);
        return ret;
}

/*
 * rename a file in an AFS filesystem and/or move it between directories
 */
static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
                      struct inode *new_dir, struct dentry *new_dentry,
                      unsigned int flags)
{
        struct afs_fs_cursor fc;
        struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
        struct key *key;
        u64 orig_data_version, new_data_version;
        bool new_negative = d_is_negative(new_dentry);
        int ret;

        if (flags)
                return -EINVAL;

        vnode = AFS_FS_I(d_inode(old_dentry));
        orig_dvnode = AFS_FS_I(old_dir);
        new_dvnode = AFS_FS_I(new_dir);
        orig_data_version = orig_dvnode->status.data_version;
        new_data_version = new_dvnode->status.data_version;

        _enter("{%llx:%llu},{%llx:%llu},{%llx:%llu},{%pd}",
               orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
               vnode->fid.vid, vnode->fid.vnode,
               new_dvnode->fid.vid, new_dvnode->fid.vnode,
               new_dentry);

        key = afs_request_key(orig_dvnode->volume->cell);
        if (IS_ERR(key)) {
                ret = PTR_ERR(key);
                goto error;
        }

        ret = -ERESTARTSYS;
        if (afs_begin_vnode_operation(&fc, orig_dvnode, key)) {
                if (orig_dvnode != new_dvnode) {
                        if (mutex_lock_interruptible_nested(&new_dvnode->io_lock, 1) < 0) {
                                afs_end_vnode_operation(&fc);
                                goto error_key;
                        }
                }
                while (afs_select_fileserver(&fc)) {
                        fc.cb_break = afs_calc_vnode_cb_break(orig_dvnode);
                        fc.cb_break_2 = afs_calc_vnode_cb_break(new_dvnode);
                        afs_fs_rename(&fc, old_dentry->d_name.name,
                                      new_dvnode, new_dentry->d_name.name,
                                      orig_data_version, new_data_version);
                }

                afs_vnode_commit_status(&fc, orig_dvnode, fc.cb_break);
                afs_vnode_commit_status(&fc, new_dvnode, fc.cb_break_2);
                if (orig_dvnode != new_dvnode)
                        mutex_unlock(&new_dvnode->io_lock);
                ret = afs_end_vnode_operation(&fc);
                if (ret < 0)
                        goto error_key;
        }

        if (ret == 0) {
                if (test_bit(AFS_VNODE_DIR_VALID, &orig_dvnode->flags))
                    afs_edit_dir_remove(orig_dvnode, &old_dentry->d_name,
                                        afs_edit_dir_for_rename);

                if (!new_negative &&
                    test_bit(AFS_VNODE_DIR_VALID, &new_dvnode->flags))
                        afs_edit_dir_remove(new_dvnode, &new_dentry->d_name,
                                            afs_edit_dir_for_rename);

                if (test_bit(AFS_VNODE_DIR_VALID, &new_dvnode->flags))
                        afs_edit_dir_add(new_dvnode, &new_dentry->d_name,
                                         &vnode->fid,  afs_edit_dir_for_rename);
        }

error_key:
        key_put(key);
error:
        _leave(" = %d", ret);
        return ret;
}

/*
 * Release a directory page and clean up its private state if it's not busy
 * - return true if the page can now be released, false if not
 */
static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags)
{
        struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);

        _enter("{{%llx:%llu}[%lu]}", dvnode->fid.vid, dvnode->fid.vnode, page->index);

        set_page_private(page, 0);
        ClearPagePrivate(page);

        /* The directory will need reloading. */
        if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                afs_stat_v(dvnode, n_relpg);
        return 1;
}

/*
 * invalidate part or all of a page
 * - release a page and clean up its private data if offset is 0 (indicating
 *   the entire page)
 */
static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
                                   unsigned int length)
{
        struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);

        _enter("{%lu},%u,%u", page->index, offset, length);

        BUG_ON(!PageLocked(page));

        /* The directory will need reloading. */
        if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
                afs_stat_v(dvnode, n_inval);

        /* we clean up only if the entire page is being invalidated */
        if (offset == 0 && length == PAGE_SIZE) {
                set_page_private(page, 0);
                ClearPagePrivate(page);
        }
}