/* dir.c: AFS filesystem directory handling
 *
 * Copyright (C) 2002 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/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/ctype.h>
#include <linux/sched.h>
#include "internal.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, void *dirent, filldir_t filldir);
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
static int afs_d_delete(const struct dentry *dentry);
static void afs_d_release(struct dentry *dentry);
static int afs_lookup_filldir(void *_cookie, 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);

const struct file_operations afs_dir_file_operations = {
        .open           = afs_dir_open,
        .release        = afs_release,
        .readdir        = 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,
};

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,
};

#define AFS_DIR_HASHTBL_SIZE    128
#define AFS_DIR_DIRENT_SIZE     32
#define AFS_DIRENT_PER_BLOCK    64

union afs_dirent {
        struct {
                uint8_t         valid;
                uint8_t         unused[1];
                __be16          hash_next;
                __be32          vnode;
                __be32          unique;
                uint8_t         name[16];
                uint8_t         overflow[4];    /* if any char of the name (inc
                                                 * NUL) reaches here, consume
                                                 * the next dirent too */
        } u;
        uint8_t extended_name[32];
};

/* AFS directory page header (one at the beginning of every 2048-byte chunk) */
struct afs_dir_pagehdr {
        __be16          npages;
        __be16          magic;
#define AFS_DIR_MAGIC htons(1234)
        uint8_t         nentries;
        uint8_t         bitmap[8];
        uint8_t         pad[19];
};

/* directory block layout */
union afs_dir_block {

        struct afs_dir_pagehdr pagehdr;

        struct {
                struct afs_dir_pagehdr  pagehdr;
                uint8_t                 alloc_ctrs[128];
                /* dir hash table */
                uint16_t                hashtable[AFS_DIR_HASHTBL_SIZE];
        } hdr;

        union afs_dirent dirents[AFS_DIRENT_PER_BLOCK];
};

/* layout on a linux VM page */
struct afs_dir_page {
        union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
};

struct afs_lookup_cookie {
        struct afs_fid  fid;
        const char      *name;
        size_t          nlen;
        int             found;
};

/*
 * check that a directory page is valid
 */
static inline void afs_dir_check_page(struct inode *dir, struct page *page)
{
        struct afs_dir_page *dbuf;
        loff_t latter;
        int tmp, qty;

#if 0
        /* check the page count */
        qty = desc.size / sizeof(dbuf->blocks[0]);
        if (qty == 0)
                goto error;

        if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {
                printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
                       __func__, dir->i_ino, qty,
                       ntohs(dbuf->blocks[0].pagehdr.npages));
                goto error;
        }
#endif

        /* determine how many magic numbers there should be in this page */
        latter = dir->i_size - page_offset(page);
        if (latter >= PAGE_SIZE)
                qty = PAGE_SIZE;
        else
                qty = latter;
        qty /= sizeof(union afs_dir_block);

        /* check them */
        dbuf = page_address(page);
        for (tmp = 0; tmp < qty; tmp++) {
                if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
                        printk("kAFS: %s(%lu): bad magic %d/%d is %04hx\n",
                               __func__, dir->i_ino, tmp, qty,
                               ntohs(dbuf->blocks[tmp].pagehdr.magic));
                        goto error;
                }
        }

        SetPageChecked(page);
        return;

error:
        SetPageChecked(page);
        SetPageError(page);
}

/*
 * discard a page cached in the pagecache
 */
static inline void afs_dir_put_page(struct page *page)
{
        kunmap(page);
        page_cache_release(page);
}

/*
 * get a page into the pagecache
 */
static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
                                     struct key *key)
{
        struct page *page;
        _enter("{%lu},%lu", dir->i_ino, index);

        page = read_cache_page(dir->i_mapping, index, afs_page_filler, key);
        if (!IS_ERR(page)) {
                kmap(page);
                if (!PageChecked(page))
                        afs_dir_check_page(dir, page);
                if (PageError(page))
                        goto fail;
        }
        return page;

fail:
        afs_dir_put_page(page);
        _leave(" = -EIO");
        return ERR_PTR(-EIO);
}

/*
 * 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_dir_block) != 2048);
        BUILD_BUG_ON(sizeof(union afs_dirent) != 32);

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

        return afs_open(inode, file);
}

/*
 * deal with one block in an AFS directory
 */
static int afs_dir_iterate_block(unsigned *fpos,
                                 union afs_dir_block *block,
                                 unsigned blkoff,
                                 void *cookie,
                                 filldir_t filldir)
{
        union afs_dirent *dire;
        unsigned offset, next, curr;
        size_t nlen;
        int tmp, ret;

        _enter("%u,%x,%p,,",*fpos,blkoff,block);

        curr = (*fpos - blkoff) / sizeof(union afs_dirent);

        /* walk through the block, an entry at a time */
        for (offset = AFS_DIRENT_PER_BLOCK - block->pagehdr.nentries;
             offset < AFS_DIRENT_PER_BLOCK;
             offset = next
             ) {
                next = offset + 1;

                /* skip entries marked unused in the bitmap */
                if (!(block->pagehdr.bitmap[offset / 8] &
                      (1 << (offset % 8)))) {
                        _debug("ENT[%Zu.%u]: unused",
                               blkoff / sizeof(union afs_dir_block), offset);
                        if (offset >= curr)
                                *fpos = blkoff +
                                        next * sizeof(union afs_dirent);
                        continue;
                }

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

                _debug("ENT[%Zu.%u]: %s %Zu \"%s\"",
                       blkoff / sizeof(union afs_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_dirent)) {
                        if (next >= AFS_DIRENT_PER_BLOCK) {
                                _debug("ENT[%Zu.%u]:"
                                       " %u travelled beyond end dir block"
                                       " (len %u/%Zu)",
                                       blkoff / sizeof(union afs_dir_block),
                                       offset, next, tmp, nlen);
                                return -EIO;
                        }
                        if (!(block->pagehdr.bitmap[next / 8] &
                              (1 << (next % 8)))) {
                                _debug("ENT[%Zu.%u]:"
                                       " %u unmarked extension (len %u/%Zu)",
                                       blkoff / sizeof(union afs_dir_block),
                                       offset, next, tmp, nlen);
                                return -EIO;
                        }

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

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

                /* found the next entry */
                ret = filldir(cookie,
                              dire->u.name,
                              nlen,
                              blkoff + offset * sizeof(union afs_dirent),
                              ntohl(dire->u.vnode),
                              filldir == afs_lookup_filldir ?
                              ntohl(dire->u.unique) : DT_UNKNOWN);
                if (ret < 0) {
                        _leave(" = 0 [full]");
                        return 0;
                }

                *fpos = blkoff + next * sizeof(union afs_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, unsigned *fpos, void *cookie,
                           filldir_t filldir, struct key *key)
{
        union afs_dir_block *dblock;
        struct afs_dir_page *dbuf;
        struct page *page;
        unsigned blkoff, limit;
        int ret;

        _enter("{%lu},%u,,", dir->i_ino, *fpos);

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

        /* round the file position up to the next entry boundary */
        *fpos += sizeof(union afs_dirent) - 1;
        *fpos &= ~(sizeof(union afs_dirent) - 1);

        /* walk through the blocks in sequence */
        ret = 0;
        while (*fpos < dir->i_size) {
                blkoff = *fpos & ~(sizeof(union afs_dir_block) - 1);

                /* fetch the appropriate page from the directory */
                page = afs_dir_get_page(dir, blkoff / PAGE_SIZE, key);
                if (IS_ERR(page)) {
                        ret = PTR_ERR(page);
                        break;
                }

                limit = blkoff & ~(PAGE_SIZE - 1);

                dbuf = page_address(page);

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

                        blkoff += sizeof(union afs_dir_block);

                } while (*fpos < dir->i_size && blkoff < limit);

                afs_dir_put_page(page);
                ret = 0;
        }

out:
        _leave(" = %d", ret);
        return ret;
}

/*
 * read an AFS directory
 */
static int afs_readdir(struct file *file, void *cookie, filldir_t filldir)
{
        unsigned fpos;
        int ret;

        _enter("{%Ld,{%lu}}",
               file->f_pos, file->f_path.dentry->d_inode->i_ino);

        ASSERT(file->private_data != NULL);

        fpos = file->f_pos;
        ret = afs_dir_iterate(file->f_path.dentry->d_inode, &fpos,
                              cookie, filldir, file->private_data);
        file->f_pos = fpos;

        _leave(" = %d", ret);
        return ret;
}

/*
 * 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(void *_cookie, const char *name, int nlen,
                              loff_t fpos, u64 ino, unsigned dtype)
{
        struct afs_lookup_cookie *cookie = _cookie;

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

        /* insanity checks first */
        BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
        BUILD_BUG_ON(sizeof(union afs_dirent) != 32);

        if (cookie->nlen != nlen || memcmp(cookie->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 in a directory
 * - just returns the FID the dentry name maps to if found
 */
static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
                         struct afs_fid *fid, struct key *key)
{
        struct afs_lookup_cookie cookie;
        struct afs_super_info *as;
        unsigned fpos;
        int ret;

        _enter("{%lu},%p{%s},", dir->i_ino, dentry, dentry->d_name.name);

        as = dir->i_sb->s_fs_info;

        /* search the directory */
        cookie.name     = dentry->d_name.name;
        cookie.nlen     = dentry->d_name.len;
        cookie.fid.vid  = as->volume->vid;
        cookie.found    = 0;

        fpos = 0;
        ret = afs_dir_iterate(dir, &fpos, &cookie, afs_lookup_filldir,
                              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=%u u=%u }", fid->vnode, fid->unique);
        return 0;
}

/*
 * Try to auto mount the mountpoint with pseudo directory, if the autocell
 * operation is setted.
 */
static struct inode *afs_try_auto_mntpt(
        int ret, struct dentry *dentry, struct inode *dir, struct key *key,
        struct afs_fid *fid)
{
        const char *devname = dentry->d_name.name;
        struct afs_vnode *vnode = AFS_FS_I(dir);
        struct inode *inode;

        _enter("%d, %p{%s}, {%x:%u}, %p",
               ret, dentry, devname, vnode->fid.vid, vnode->fid.vnode, key);

        if (ret != -ENOENT ||
            !test_bit(AFS_VNODE_AUTOCELL, &vnode->flags))
                goto out;

        inode = afs_iget_autocell(dir, devname, strlen(devname), key);
        if (IS_ERR(inode)) {
                ret = PTR_ERR(inode);
                goto out;
        }

        *fid = AFS_FS_I(inode)->fid;
        _leave("= %p", inode);
        return inode;

out:
        _leave("= %d", ret);
        return ERR_PTR(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 *vnode;
        struct afs_fid fid;
        struct inode *inode;
        struct key *key;
        int ret;

        vnode = AFS_FS_I(dir);

        _enter("{%x:%u},%p{%s},",
               vnode->fid.vid, vnode->fid.vnode, dentry, dentry->d_name.name);

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

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

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

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

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

        ret = afs_do_lookup(dir, dentry, &fid, key);
        if (ret < 0) {
                inode = afs_try_auto_mntpt(ret, dentry, dir, key, &fid);
                if (!IS_ERR(inode)) {
                        key_put(key);
                        goto success;
                }

                ret = PTR_ERR(inode);
                key_put(key);
                if (ret == -ENOENT) {
                        d_add(dentry, NULL);
                        _leave(" = NULL [negative]");
                        return NULL;
                }
                _leave(" = %d [do]", ret);
                return ERR_PTR(ret);
        }
        dentry->d_fsdata = (void *)(unsigned long) vnode->status.data_version;

        /* instantiate the dentry */
        inode = afs_iget(dir->i_sb, key, &fid, NULL, NULL);
        key_put(key);
        if (IS_ERR(inode)) {
                _leave(" = %ld", PTR_ERR(inode));
                return ERR_CAST(inode);
        }

success:
        d_add(dentry, inode);
        _leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%u }",
               fid.vnode,
               fid.unique,
               dentry->d_inode->i_ino,
               dentry->d_inode->i_generation);

        return NULL;
}

/*
 * 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 key *key;
        void *dir_version;
        int ret;

        if (flags & LOOKUP_RCU)
                return -ECHILD;

        vnode = AFS_FS_I(dentry->d_inode);

        if (dentry->d_inode)
                _enter("{v={%x:%u} n=%s fl=%lx},",
                       vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
                       vnode->flags);
        else
                _enter("{neg n=%s}", dentry->d_name.name);

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

        /* lock down the parent dentry so we can peer at it */
        parent = dget_parent(dentry);
        if (!parent->d_inode)
                goto out_bad;

        dir = AFS_FS_I(parent->d_inode);

        /* validate the parent directory */
        if (test_bit(AFS_VNODE_MODIFIED, &dir->flags))
                afs_validate(dir, key);

        if (test_bit(AFS_VNODE_DELETED, &dir->flags)) {
                _debug("%s: parent dir deleted", dentry->d_name.name);
                goto out_bad;
        }

        dir_version = (void *) (unsigned long) dir->status.data_version;
        if (dentry->d_fsdata == dir_version)
                goto out_valid; /* the dir contents are unchanged */

        _debug("dir modified");

        /* search the directory for this vnode */
        ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
        switch (ret) {
        case 0:
                /* the filename maps to something */
                if (!dentry->d_inode)
                        goto out_bad;
                if (is_bad_inode(dentry->d_inode)) {
                        printk("kAFS: afs_d_revalidate: %s/%s has bad inode\n",
                               parent->d_name.name, dentry->d_name.name);
                        goto out_bad;
                }

                /* if the vnode ID has changed, then the dirent points to a
                 * different file */
                if (fid.vnode != vnode->fid.vnode) {
                        _debug("%s: dirent changed [%u != %u]",
                               dentry->d_name.name, 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("%s: file deleted (uq %u -> %u I:%u)",
                               dentry->d_name.name, fid.unique,
                               vnode->fid.unique,
                               dentry->d_inode->i_generation);
                        spin_lock(&vnode->lock);
                        set_bit(AFS_VNODE_DELETED, &vnode->flags);
                        spin_unlock(&vnode->lock);
                        goto not_found;
                }
                goto out_valid;

        case -ENOENT:
                /* the filename is unknown */
                _debug("%s: dirent not found", dentry->d_name.name);
                if (dentry->d_inode)
                        goto not_found;
                goto out_valid;

        default:
                _debug("failed to iterate dir %s: %d",
                       parent->d_name.name, ret);
                goto out_bad;
        }

out_valid:
        dentry->d_fsdata = dir_version;
out_skip:
        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:
        if (dentry->d_inode) {
                /* don't unhash if we have submounts */
                if (have_submounts(dentry))
                        goto out_skip;
        }

        _debug("dropping dentry %s/%s",
               parent->d_name.name, dentry->d_name.name);
        shrink_dcache_parent(dentry);
        d_drop(dentry);
        dput(parent);
        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("%s", dentry->d_name.name);

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

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

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

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

/*
 * handle dentry release
 */
static void afs_d_release(struct dentry *dentry)
{
        _enter("%s", dentry->d_name.name);
}

/*
 * create a directory on an AFS filesystem
 */
static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
{
        struct afs_file_status status;
        struct afs_callback cb;
        struct afs_server *server;
        struct afs_vnode *dvnode, *vnode;
        struct afs_fid fid;
        struct inode *inode;
        struct key *key;
        int ret;

        dvnode = AFS_FS_I(dir);

        _enter("{%x:%u},{%s},%ho",
               dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, 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;
        }

        mode |= S_IFDIR;
        ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
                               mode, &fid, &status, &cb, &server);
        if (ret < 0)
                goto mkdir_error;

        inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
        if (IS_ERR(inode)) {
                /* ENOMEM at a really inconvenient time - just abandon the new
                 * directory on the server */
                ret = PTR_ERR(inode);
                goto iget_error;
        }

        /* apply the status report we've got for the new vnode */
        vnode = AFS_FS_I(inode);
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);
        afs_vnode_finalise_status_update(vnode, server);
        afs_put_server(server);

        d_instantiate(dentry, inode);
        if (d_unhashed(dentry)) {
                _debug("not hashed");
                d_rehash(dentry);
        }
        key_put(key);
        _leave(" = 0");
        return 0;

iget_error:
        afs_put_server(server);
mkdir_error:
        key_put(key);
error:
        d_drop(dentry);
        _leave(" = %d", ret);
        return ret;
}

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

        dvnode = AFS_FS_I(dir);

        _enter("{%x:%u},{%s}",
               dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name);

        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 = afs_vnode_remove(dvnode, key, dentry->d_name.name, true);
        if (ret < 0)
                goto rmdir_error;

        if (dentry->d_inode) {
                vnode = AFS_FS_I(dentry->d_inode);
                clear_nlink(&vnode->vfs_inode);
                set_bit(AFS_VNODE_DELETED, &vnode->flags);
                afs_discard_callback_on_delete(vnode);
        }

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

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

/*
 * remove a file from an AFS filesystem
 */
static int afs_unlink(struct inode *dir, struct dentry *dentry)
{
        struct afs_vnode *dvnode, *vnode;
        struct key *key;
        int ret;

        dvnode = AFS_FS_I(dir);

        _enter("{%x:%u},{%s}",
               dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name);

        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;
        }

        if (dentry->d_inode) {
                vnode = AFS_FS_I(dentry->d_inode);

                /* make sure we have a callback promise on the victim */
                ret = afs_validate(vnode, key);
                if (ret < 0)
                        goto error;
        }

        ret = afs_vnode_remove(dvnode, key, dentry->d_name.name, false);
        if (ret < 0)
                goto remove_error;

        if (dentry->d_inode) {
                /* if the file wasn't 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...
                 */
                vnode = AFS_FS_I(dentry->d_inode);
                if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
                        _debug("AFS_VNODE_DELETED");
                if (test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags))
                        _debug("AFS_VNODE_CB_BROKEN");
                set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
                ret = afs_validate(vnode, key);
                _debug("nlink %d [val %d]", vnode->vfs_inode.i_nlink, ret);
        }

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

remove_error:
        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_file_status status;
        struct afs_callback cb;
        struct afs_server *server;
        struct afs_vnode *dvnode, *vnode;
        struct afs_fid fid;
        struct inode *inode;
        struct key *key;
        int ret;

        dvnode = AFS_FS_I(dir);

        _enter("{%x:%u},{%s},%ho,",
               dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, 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;
        }

        mode |= S_IFREG;
        ret = afs_vnode_create(dvnode, key, dentry->d_name.name,
                               mode, &fid, &status, &cb, &server);
        if (ret < 0)
                goto create_error;

        inode = afs_iget(dir->i_sb, key, &fid, &status, &cb);
        if (IS_ERR(inode)) {
                /* ENOMEM at a really inconvenient time - just abandon the new
                 * directory on the server */
                ret = PTR_ERR(inode);
                goto iget_error;
        }

        /* apply the status report we've got for the new vnode */
        vnode = AFS_FS_I(inode);
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);
        afs_vnode_finalise_status_update(vnode, server);
        afs_put_server(server);

        d_instantiate(dentry, inode);

        if (d_unhashed(dentry)) {
                _debug("not hashed");
                d_rehash(dentry);
        }
        key_put(key);
        _leave(" = 0");
        return 0;

iget_error:
        afs_put_server(server);
create_error:
        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_vnode *dvnode, *vnode;
        struct key *key;
        int ret;

        vnode = AFS_FS_I(from->d_inode);
        dvnode = AFS_FS_I(dir);

        _enter("{%x:%u},{%x:%u},{%s}",
               vnode->fid.vid, vnode->fid.vnode,
               dvnode->fid.vid, dvnode->fid.vnode,
               dentry->d_name.name);

        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 = afs_vnode_link(dvnode, vnode, key, dentry->d_name.name);
        if (ret < 0)
                goto link_error;

        ihold(&vnode->vfs_inode);
        d_instantiate(dentry, &vnode->vfs_inode);
        key_put(key);
        _leave(" = 0");
        return 0;

link_error:
        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_file_status status;
        struct afs_server *server;
        struct afs_vnode *dvnode, *vnode;
        struct afs_fid fid;
        struct inode *inode;
        struct key *key;
        int ret;

        dvnode = AFS_FS_I(dir);

        _enter("{%x:%u},{%s},%s",
               dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name,
               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 = afs_vnode_symlink(dvnode, key, dentry->d_name.name, content,
                                &fid, &status, &server);
        if (ret < 0)
                goto create_error;

        inode = afs_iget(dir->i_sb, key, &fid, &status, NULL);
        if (IS_ERR(inode)) {
                /* ENOMEM at a really inconvenient time - just abandon the new
                 * directory on the server */
                ret = PTR_ERR(inode);
                goto iget_error;
        }

        /* apply the status report we've got for the new vnode */
        vnode = AFS_FS_I(inode);
        spin_lock(&vnode->lock);
        vnode->update_cnt++;
        spin_unlock(&vnode->lock);
        afs_vnode_finalise_status_update(vnode, server);
        afs_put_server(server);

        d_instantiate(dentry, inode);
        if (d_unhashed(dentry)) {
                _debug("not hashed");
                d_rehash(dentry);
        }
        key_put(key);
        _leave(" = 0");
        return 0;

iget_error:
        afs_put_server(server);
create_error:
        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)
{
        struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;
        struct key *key;
        int ret;

        vnode = AFS_FS_I(old_dentry->d_inode);
        orig_dvnode = AFS_FS_I(old_dir);
        new_dvnode = AFS_FS_I(new_dir);

        _enter("{%x:%u},{%x:%u},{%x:%u},{%s}",
               orig_dvnode->fid.vid, orig_dvnode->fid.vnode,
               vnode->fid.vid, vnode->fid.vnode,
               new_dvnode->fid.vid, new_dvnode->fid.vnode,
               new_dentry->d_name.name);

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

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

        ret = afs_vnode_rename(orig_dvnode, new_dvnode, key,
                               old_dentry->d_name.name,
                               new_dentry->d_name.name);
        if (ret < 0)
                goto rename_error;
        key_put(key);
        _leave(" = 0");
        return 0;

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