ClabureDB: Classified Bug-Reports Database

   /*
    *  linux/fs/nfs/inode.c
    *
    *  Copyright (C) 1992  Rick Sladkey
    *
    *  nfs inode and superblock handling functions
    *
    *  Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
    *  experimental NFS changes. Modularisation taken straight from SYS5 fs.
   *
   *  Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
   *  J.S.Peatfield@damtp.cam.ac.uk
   *
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/sched.h>
  #include <linux/time.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/string.h>
  #include <linux/stat.h>
  #include <linux/errno.h>
  #include <linux/unistd.h>
  #include <linux/sunrpc/clnt.h>
  #include <linux/sunrpc/stats.h>
  #include <linux/sunrpc/metrics.h>
  #include <linux/nfs_fs.h>
  #include <linux/nfs_mount.h>
  #include <linux/nfs4_mount.h>
  #include <linux/lockd/bind.h>
  #include <linux/smp_lock.h>
  #include <linux/seq_file.h>
  #include <linux/mount.h>
  #include <linux/nfs_idmap.h>
  #include <linux/vfs.h>
  #include <linux/inet.h>
  #include <linux/nfs_xdr.h>
  
  #include <asm/system.h>
  #include <asm/uaccess.h>
  
  #include "nfs4_fs.h"
  #include "callback.h"
  #include "delegation.h"
  #include "iostat.h"
  #include "internal.h"
  
  #define NFSDBG_FACILITY                NFSDBG_VFS
  
  #define NFS_64_BIT_INODE_NUMBERS_ENABLED        1
  
  /* Default is to see 64-bit inode numbers */
  static int enable_ino64 = NFS_64_BIT_INODE_NUMBERS_ENABLED;
  
  static void nfs_invalidate_inode(struct inode *);
  static int nfs_update_inode(struct inode *, struct nfs_fattr *);
  
  static struct kmem_cache * nfs_inode_cachep;
  
  static inline unsigned long
  nfs_fattr_to_ino_t(struct nfs_fattr *fattr)
  {
          return nfs_fileid_to_ino_t(fattr->fileid);
  }
  
  /**
   * nfs_compat_user_ino64 - returns the user-visible inode number
   * @fileid: 64-bit fileid
   *
   * This function returns a 32-bit inode number if the boot parameter
   * nfs.enable_ino64 is zero.
   */
  u64 nfs_compat_user_ino64(u64 fileid)
  {
          int ino;
  
          if (enable_ino64)
                  return fileid;
          ino = fileid;
          if (sizeof(ino) < sizeof(fileid))
                  ino ^= fileid >> (sizeof(fileid)-sizeof(ino)) * 8;
          return ino;
  }
  
  int nfs_write_inode(struct inode *inode, int sync)
  {
          int ret;
  
          if (sync) {
                  ret = filemap_fdatawait(inode->i_mapping);
                  if (ret == 0)
                          ret = nfs_commit_inode(inode, FLUSH_SYNC);
          } else
                  ret = nfs_commit_inode(inode, 0);
          if (ret >= 0)
                  return 0;
          __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
         return ret;
 }
 
 void nfs_clear_inode(struct inode *inode)
 {
         /*
          * The following should never happen...
          */
         BUG_ON(nfs_have_writebacks(inode));
         BUG_ON(!list_empty(&NFS_I(inode)->open_files));
         nfs_zap_acl_cache(inode);
         nfs_access_zap_cache(inode);
 }
 
 /**
  * nfs_sync_mapping - helper to flush all mmapped dirty data to disk
  */
 int nfs_sync_mapping(struct address_space *mapping)
 {
         int ret;
 
         if (mapping->nrpages == 0)
                 return 0;
         unmap_mapping_range(mapping, 0, 0, 0);
         ret = filemap_write_and_wait(mapping);
         if (ret != 0)
                 goto out;
         ret = nfs_wb_all(mapping->host);
 out:
         return ret;
 }
 
 /*
  * Invalidate the local caches
  */
 static void nfs_zap_caches_locked(struct inode *inode)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
         int mode = inode->i_mode;
 
         nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);
 
         nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
         nfsi->attrtimeo_timestamp = jiffies;
 
         memset(NFS_COOKIEVERF(inode), 0, sizeof(NFS_COOKIEVERF(inode)));
         if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))
                 nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL|NFS_INO_REVAL_PAGECACHE;
         else
                 nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL|NFS_INO_REVAL_PAGECACHE;
 }
 
 void nfs_zap_caches(struct inode *inode)
 {
         spin_lock(&inode->i_lock);
         nfs_zap_caches_locked(inode);
         spin_unlock(&inode->i_lock);
 }
 
 void nfs_zap_mapping(struct inode *inode, struct address_space *mapping)
 {
         if (mapping->nrpages != 0) {
                 spin_lock(&inode->i_lock);
                 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA;
                 spin_unlock(&inode->i_lock);
         }
 }
 
 void nfs_zap_acl_cache(struct inode *inode)
 {
         void (*clear_acl_cache)(struct inode *);
 
         clear_acl_cache = NFS_PROTO(inode)->clear_acl_cache;
         if (clear_acl_cache != NULL)
                 clear_acl_cache(inode);
         spin_lock(&inode->i_lock);
         NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_ACL;
         spin_unlock(&inode->i_lock);
 }
 
 void nfs_invalidate_atime(struct inode *inode)
 {
         spin_lock(&inode->i_lock);
         NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME;
         spin_unlock(&inode->i_lock);
 }
 
 /*
  * Invalidate, but do not unhash, the inode.
  * NB: must be called with inode->i_lock held!
  */
 static void nfs_invalidate_inode(struct inode *inode)
 {
         set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
         nfs_zap_caches_locked(inode);
 }
 
 struct nfs_find_desc {
         struct nfs_fh                *fh;
         struct nfs_fattr        *fattr;
 };
 
 /*
  * In NFSv3 we can have 64bit inode numbers. In order to support
  * this, and re-exported directories (also seen in NFSv2)
  * we are forced to allow 2 different inodes to have the same
  * i_ino.
  */
 static int
 nfs_find_actor(struct inode *inode, void *opaque)
 {
         struct nfs_find_desc        *desc = (struct nfs_find_desc *)opaque;
         struct nfs_fh                *fh = desc->fh;
         struct nfs_fattr        *fattr = desc->fattr;
 
         if (NFS_FILEID(inode) != fattr->fileid)
                 return 0;
         if (nfs_compare_fh(NFS_FH(inode), fh))
                 return 0;
         if (is_bad_inode(inode) || NFS_STALE(inode))
                 return 0;
         return 1;
 }
 
 static int
 nfs_init_locked(struct inode *inode, void *opaque)
 {
         struct nfs_find_desc        *desc = (struct nfs_find_desc *)opaque;
         struct nfs_fattr        *fattr = desc->fattr;
 
         set_nfs_fileid(inode, fattr->fileid);
         nfs_copy_fh(NFS_FH(inode), desc->fh);
         return 0;
 }
 
 /* Don't use READDIRPLUS on directories that we believe are too large */
 #define NFS_LIMIT_READDIRPLUS (8*PAGE_SIZE)
 
 /*
  * This is our front-end to iget that looks up inodes by file handle
  * instead of inode number.
  */
 struct inode *
 nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
 {
         struct nfs_find_desc desc = {
                 .fh        = fh,
                 .fattr        = fattr
         };
         struct inode *inode = ERR_PTR(-ENOENT);
         unsigned long hash;
 
         if ((fattr->valid & NFS_ATTR_FATTR) == 0)
                 goto out_no_inode;
 
         if (!fattr->nlink) {
                 printk("NFS: Buggy server - nlink == 0!\n");
                 goto out_no_inode;
         }
 
         hash = nfs_fattr_to_ino_t(fattr);
 
         inode = iget5_locked(sb, hash, nfs_find_actor, nfs_init_locked, &desc);
         if (inode == NULL) {
                 inode = ERR_PTR(-ENOMEM);
                 goto out_no_inode;
         }
 
         if (inode->i_state & I_NEW) {
                 struct nfs_inode *nfsi = NFS_I(inode);
                 unsigned long now = jiffies;
 
                 /* We set i_ino for the few things that still rely on it,
                  * such as stat(2) */
                 inode->i_ino = hash;
 
                 /* We can't support update_atime(), since the server will reset it */
                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
                 inode->i_mode = fattr->mode;
                 /* Why so? Because we want revalidate for devices/FIFOs, and
                  * that's precisely what we have in nfs_file_inode_operations.
                  */
                 inode->i_op = NFS_SB(sb)->nfs_client->rpc_ops->file_inode_ops;
                 if (S_ISREG(inode->i_mode)) {
                         inode->i_fop = &nfs_file_operations;
                         inode->i_data.a_ops = &nfs_file_aops;
                         inode->i_data.backing_dev_info = &NFS_SB(sb)->backing_dev_info;
                 } else if (S_ISDIR(inode->i_mode)) {
                         inode->i_op = NFS_SB(sb)->nfs_client->rpc_ops->dir_inode_ops;
                         inode->i_fop = &nfs_dir_operations;
                         if (nfs_server_capable(inode, NFS_CAP_READDIRPLUS)
                             && fattr->size <= NFS_LIMIT_READDIRPLUS)
                                 set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
                         /* Deal with crossing mountpoints */
                         if (!nfs_fsid_equal(&NFS_SB(sb)->fsid, &fattr->fsid)) {
                                 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
                                         inode->i_op = &nfs_referral_inode_operations;
                                 else
                                         inode->i_op = &nfs_mountpoint_inode_operations;
                                 inode->i_fop = NULL;
                                 set_bit(NFS_INO_MOUNTPOINT, &nfsi->flags);
                         }
                 } else if (S_ISLNK(inode->i_mode))
                         inode->i_op = &nfs_symlink_inode_operations;
                 else
                         init_special_inode(inode, inode->i_mode, fattr->rdev);
 
                 nfsi->read_cache_jiffies = fattr->time_start;
                 nfsi->attr_gencount = fattr->gencount;
                 inode->i_atime = fattr->atime;
                 inode->i_mtime = fattr->mtime;
                 inode->i_ctime = fattr->ctime;
                 if (fattr->valid & NFS_ATTR_FATTR_V4)
                         nfsi->change_attr = fattr->change_attr;
                 inode->i_size = nfs_size_to_loff_t(fattr->size);
                 inode->i_nlink = fattr->nlink;
                 inode->i_uid = fattr->uid;
                 inode->i_gid = fattr->gid;
                 if (fattr->valid & (NFS_ATTR_FATTR_V3 | NFS_ATTR_FATTR_V4)) {
                         /*
                          * report the blocks in 512byte units
                          */
                         inode->i_blocks = nfs_calc_block_size(fattr->du.nfs3.used);
                 } else {
                         inode->i_blocks = fattr->du.nfs2.blocks;
                 }
                 nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
                 nfsi->attrtimeo_timestamp = now;
                 memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
                 nfsi->access_cache = RB_ROOT;
 
                 unlock_new_inode(inode);
         } else
                 nfs_refresh_inode(inode, fattr);
         dprintk("NFS: nfs_fhget(%s/%Ld ct=%d)\n",
                 inode->i_sb->s_id,
                 (long long)NFS_FILEID(inode),
                 atomic_read(&inode->i_count));
 
 out:
         return inode;
 
 out_no_inode:
         dprintk("nfs_fhget: iget failed with error %ld\n", PTR_ERR(inode));
         goto out;
 }
 
 #define NFS_VALID_ATTRS (ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_SIZE|ATTR_ATIME|ATTR_ATIME_SET|ATTR_MTIME|ATTR_MTIME_SET|ATTR_FILE)
 
 int
 nfs_setattr(struct dentry *dentry, struct iattr *attr)
 {
         struct inode *inode = dentry->d_inode;
         struct nfs_fattr fattr;
         int error;
 
         nfs_inc_stats(inode, NFSIOS_VFSSETATTR);
 
         /* skip mode change if it's just for clearing setuid/setgid */
         if (attr->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
                 attr->ia_valid &= ~ATTR_MODE;
 
         if (attr->ia_valid & ATTR_SIZE) {
                 if (!S_ISREG(inode->i_mode) || attr->ia_size == i_size_read(inode))
                         attr->ia_valid &= ~ATTR_SIZE;
         }
 
         /* Optimization: if the end result is no change, don't RPC */
         attr->ia_valid &= NFS_VALID_ATTRS;
         if ((attr->ia_valid & ~ATTR_FILE) == 0)
                 return 0;
 
         /* Write all dirty data */
         if (S_ISREG(inode->i_mode)) {
                 filemap_write_and_wait(inode->i_mapping);
                 nfs_wb_all(inode);
         }
         /*
          * Return any delegations if we're going to change ACLs
          */
         if ((attr->ia_valid & (ATTR_MODE|ATTR_UID|ATTR_GID)) != 0)
                 nfs_inode_return_delegation(inode);
         error = NFS_PROTO(inode)->setattr(dentry, &fattr, attr);
         if (error == 0)
                 nfs_refresh_inode(inode, &fattr);
         return error;
 }
 
 /**
  * nfs_vmtruncate - unmap mappings "freed" by truncate() syscall
  * @inode: inode of the file used
  * @offset: file offset to start truncating
  *
  * This is a copy of the common vmtruncate, but with the locking
  * corrected to take into account the fact that NFS requires
  * inode->i_size to be updated under the inode->i_lock.
  */
 static int nfs_vmtruncate(struct inode * inode, loff_t offset)
 {
         if (i_size_read(inode) < offset) {
                 unsigned long limit;
 
                 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
                 if (limit != RLIM_INFINITY && offset > limit)
                         goto out_sig;
                 if (offset > inode->i_sb->s_maxbytes)
                         goto out_big;
                 spin_lock(&inode->i_lock);
                 i_size_write(inode, offset);
                 spin_unlock(&inode->i_lock);
         } else {
                 struct address_space *mapping = inode->i_mapping;
 
                 /*
                  * truncation of in-use swapfiles is disallowed - it would
                  * cause subsequent swapout to scribble on the now-freed
                  * blocks.
                  */
                 if (IS_SWAPFILE(inode))
                         return -ETXTBSY;
                 spin_lock(&inode->i_lock);
                 i_size_write(inode, offset);
                 spin_unlock(&inode->i_lock);
 
                 /*
                  * unmap_mapping_range is called twice, first simply for
                  * efficiency so that truncate_inode_pages does fewer
                  * single-page unmaps.  However after this first call, and
                  * before truncate_inode_pages finishes, it is possible for
                  * private pages to be COWed, which remain after
                  * truncate_inode_pages finishes, hence the second
                  * unmap_mapping_range call must be made for correctness.
                  */
                 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
                 truncate_inode_pages(mapping, offset);
                 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
         }
         return 0;
 out_sig:
         send_sig(SIGXFSZ, current, 0);
 out_big:
         return -EFBIG;
 }
 
 /**
  * nfs_setattr_update_inode - Update inode metadata after a setattr call.
  * @inode: pointer to struct inode
  * @attr: pointer to struct iattr
  *
  * Note: we do this in the *proc.c in order to ensure that
  *       it works for things like exclusive creates too.
  */
 void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
 {
         if ((attr->ia_valid & (ATTR_MODE|ATTR_UID|ATTR_GID)) != 0) {
                 spin_lock(&inode->i_lock);
                 if ((attr->ia_valid & ATTR_MODE) != 0) {
                         int mode = attr->ia_mode & S_IALLUGO;
                         mode |= inode->i_mode & ~S_IALLUGO;
                         inode->i_mode = mode;
                 }
                 if ((attr->ia_valid & ATTR_UID) != 0)
                         inode->i_uid = attr->ia_uid;
                 if ((attr->ia_valid & ATTR_GID) != 0)
                         inode->i_gid = attr->ia_gid;
                 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
                 spin_unlock(&inode->i_lock);
         }
         if ((attr->ia_valid & ATTR_SIZE) != 0) {
                 nfs_inc_stats(inode, NFSIOS_SETATTRTRUNC);
                 nfs_vmtruncate(inode, attr->ia_size);
         }
 }
 
 int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
 {
         struct inode *inode = dentry->d_inode;
         int need_atime = NFS_I(inode)->cache_validity & NFS_INO_INVALID_ATIME;
         int err;
 
         /*
          * Flush out writes to the server in order to update c/mtime.
          *
          * Hold the i_mutex to suspend application writes temporarily;
          * this prevents long-running writing applications from blocking
          * nfs_wb_nocommit.
          */
         if (S_ISREG(inode->i_mode)) {
                 mutex_lock(&inode->i_mutex);
                 nfs_wb_nocommit(inode);
                 mutex_unlock(&inode->i_mutex);
         }
 
         /*
          * We may force a getattr if the user cares about atime.
          *
          * Note that we only have to check the vfsmount flags here:
          *  - NFS always sets S_NOATIME by so checking it would give a
          *    bogus result
          *  - NFS never sets MS_NOATIME or MS_NODIRATIME so there is
          *    no point in checking those.
          */
          if ((mnt->mnt_flags & MNT_NOATIME) ||
              ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
                 need_atime = 0;
 
         if (need_atime)
                 err = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
         else
                 err = nfs_revalidate_inode(NFS_SERVER(inode), inode);
         if (!err) {
                 generic_fillattr(inode, stat);
                 stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
         }
         return err;
 }
 
 static struct nfs_open_context *alloc_nfs_open_context(struct vfsmount *mnt, struct dentry *dentry, struct rpc_cred *cred)
 {
         struct nfs_open_context *ctx;
 
         ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
         if (ctx != NULL) {
                 ctx->path.dentry = dget(dentry);
                 ctx->path.mnt = mntget(mnt);
                 ctx->cred = get_rpccred(cred);
                 ctx->state = NULL;
                 ctx->lockowner = current->files;
                 ctx->flags = 0;
                 ctx->error = 0;
                 ctx->dir_cookie = 0;
                 atomic_set(&ctx->count, 1);
         }
         return ctx;
 }
 
 struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx)
 {
         if (ctx != NULL)
                 atomic_inc(&ctx->count);
         return ctx;
 }
 
 static void __put_nfs_open_context(struct nfs_open_context *ctx, int wait)
 {
         struct inode *inode;
 
         if (ctx == NULL)
                 return;
 
         inode = ctx->path.dentry->d_inode;
         if (!atomic_dec_and_lock(&ctx->count, &inode->i_lock))
                 return;
         list_del(&ctx->list);
         spin_unlock(&inode->i_lock);
         if (ctx->state != NULL) {
                 if (wait)
                         nfs4_close_sync(&ctx->path, ctx->state, ctx->mode);
                 else
                         nfs4_close_state(&ctx->path, ctx->state, ctx->mode);
         }
         if (ctx->cred != NULL)
                 put_rpccred(ctx->cred);
         path_put(&ctx->path);
         kfree(ctx);
 }
 
 void put_nfs_open_context(struct nfs_open_context *ctx)
 {
         __put_nfs_open_context(ctx, 0);
 }
 
 static void put_nfs_open_context_sync(struct nfs_open_context *ctx)
 {
         __put_nfs_open_context(ctx, 1);
 }
 
 /*
  * Ensure that mmap has a recent RPC credential for use when writing out
  * shared pages
  */
 static void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx)
 {
         struct inode *inode = filp->f_path.dentry->d_inode;
         struct nfs_inode *nfsi = NFS_I(inode);
 
         filp->private_data = get_nfs_open_context(ctx);
         spin_lock(&inode->i_lock);
         list_add(&ctx->list, &nfsi->open_files);
         spin_unlock(&inode->i_lock);
 }
 
 /*
  * Given an inode, search for an open context with the desired characteristics
  */
 struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, int mode)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
         struct nfs_open_context *pos, *ctx = NULL;
 
         spin_lock(&inode->i_lock);
         list_for_each_entry(pos, &nfsi->open_files, list) {
                 if (cred != NULL && pos->cred != cred)
                         continue;
                 if ((pos->mode & mode) == mode) {
                         ctx = get_nfs_open_context(pos);
                         break;
                 }
         }
         spin_unlock(&inode->i_lock);
         return ctx;
 }
 
 static void nfs_file_clear_open_context(struct file *filp)
 {
         struct inode *inode = filp->f_path.dentry->d_inode;
         struct nfs_open_context *ctx = nfs_file_open_context(filp);
 
         if (ctx) {
                 filp->private_data = NULL;
                 spin_lock(&inode->i_lock);
                 list_move_tail(&ctx->list, &NFS_I(inode)->open_files);
                 spin_unlock(&inode->i_lock);
                 put_nfs_open_context_sync(ctx);
         }
 }
 
 /*
  * These allocate and release file read/write context information.
  */
 int nfs_open(struct inode *inode, struct file *filp)
 {
         struct nfs_open_context *ctx;
         struct rpc_cred *cred;
 
         cred = rpc_lookup_cred();
         if (IS_ERR(cred))
                 return PTR_ERR(cred);
         ctx = alloc_nfs_open_context(filp->f_path.mnt, filp->f_path.dentry, cred);
         put_rpccred(cred);
         if (ctx == NULL)
                 return -ENOMEM;
         ctx->mode = filp->f_mode;
         nfs_file_set_open_context(filp, ctx);
         put_nfs_open_context(ctx);
         return 0;
 }
 
 int nfs_release(struct inode *inode, struct file *filp)
 {
         nfs_file_clear_open_context(filp);
         return 0;
 }
 
 /*
  * This function is called whenever some part of NFS notices that
  * the cached attributes have to be refreshed.
  */
 int
 __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
 {
         int                 status = -ESTALE;
         struct nfs_fattr fattr;
         struct nfs_inode *nfsi = NFS_I(inode);
 
         dfprintk(PAGECACHE, "NFS: revalidating (%s/%Ld)\n",
                 inode->i_sb->s_id, (long long)NFS_FILEID(inode));
 
         if (is_bad_inode(inode))
                 goto out;
         if (NFS_STALE(inode))
                 goto out;
 
         if (NFS_STALE(inode))
                 goto out;
 
         nfs_inc_stats(inode, NFSIOS_INODEREVALIDATE);
         status = NFS_PROTO(inode)->getattr(server, NFS_FH(inode), &fattr);
         if (status != 0) {
                 dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) getattr failed, error=%d\n",
                          inode->i_sb->s_id,
                          (long long)NFS_FILEID(inode), status);
                 if (status == -ESTALE) {
                         nfs_zap_caches(inode);
                         if (!S_ISDIR(inode->i_mode))
                                 set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
                 }
                 goto out;
         }
 
         status = nfs_refresh_inode(inode, &fattr);
         if (status) {
                 dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) refresh failed, error=%d\n",
                          inode->i_sb->s_id,
                          (long long)NFS_FILEID(inode), status);
                 goto out;
         }
 
         if (nfsi->cache_validity & NFS_INO_INVALID_ACL)
                 nfs_zap_acl_cache(inode);
 
         dfprintk(PAGECACHE, "NFS: (%s/%Ld) revalidation complete\n",
                 inode->i_sb->s_id,
                 (long long)NFS_FILEID(inode));
 
  out:
         return status;
 }
 
 int nfs_attribute_timeout(struct inode *inode)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
 
         if (nfs_have_delegation(inode, FMODE_READ))
                 return 0;
         /*
          * Special case: if the attribute timeout is set to 0, then always
          *                  treat the cache as having expired (unless holding
          *                  a delegation).
          */
         if (nfsi->attrtimeo == 0)
                 return 1;
         return !time_in_range(jiffies, nfsi->read_cache_jiffies, nfsi->read_cache_jiffies + nfsi->attrtimeo);
 }
 
 /**
  * nfs_revalidate_inode - Revalidate the inode attributes
  * @server - pointer to nfs_server struct
  * @inode - pointer to inode struct
  *
  * Updates inode attribute information by retrieving the data from the server.
  */
 int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
 {
         if (!(NFS_I(inode)->cache_validity & NFS_INO_INVALID_ATTR)
                         && !nfs_attribute_timeout(inode))
                 return NFS_STALE(inode) ? -ESTALE : 0;
         return __nfs_revalidate_inode(server, inode);
 }
 
 static int nfs_invalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
         
         if (mapping->nrpages != 0) {
                 int ret = invalidate_inode_pages2(mapping);
                 if (ret < 0)
                         return ret;
         }
         spin_lock(&inode->i_lock);
         nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
         if (S_ISDIR(inode->i_mode))
                 memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
         spin_unlock(&inode->i_lock);
         nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
         dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
                         inode->i_sb->s_id, (long long)NFS_FILEID(inode));
         return 0;
 }
 
 static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
 {
         int ret = 0;
 
         mutex_lock(&inode->i_mutex);
         if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_DATA) {
                 ret = nfs_sync_mapping(mapping);
                 if (ret == 0)
                         ret = nfs_invalidate_mapping_nolock(inode, mapping);
         }
         mutex_unlock(&inode->i_mutex);
         return ret;
 }
 
 /**
  * nfs_revalidate_mapping_nolock - Revalidate the pagecache
  * @inode - pointer to host inode
  * @mapping - pointer to mapping
  */
 int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
         int ret = 0;
 
         if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
                         || nfs_attribute_timeout(inode) || NFS_STALE(inode)) {
                 ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
                 if (ret < 0)
                         goto out;
         }
         if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
                 ret = nfs_invalidate_mapping_nolock(inode, mapping);
 out:
         return ret;
 }
 
 /**
  * nfs_revalidate_mapping - Revalidate the pagecache
  * @inode - pointer to host inode
  * @mapping - pointer to mapping
  *
  * This version of the function will take the inode->i_mutex and attempt to
  * flush out all dirty data if it needs to invalidate the page cache.
  */
 int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
         int ret = 0;
 
         if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
                         || nfs_attribute_timeout(inode) || NFS_STALE(inode)) {
                 ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
                 if (ret < 0)
                         goto out;
         }
         if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
                 ret = nfs_invalidate_mapping(inode, mapping);
 out:
         return ret;
 }
 
 static void nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
 
         if ((fattr->valid & NFS_ATTR_WCC_V4) != 0 &&
                         nfsi->change_attr == fattr->pre_change_attr) {
                 nfsi->change_attr = fattr->change_attr;
                 if (S_ISDIR(inode->i_mode))
                         nfsi->cache_validity |= NFS_INO_INVALID_DATA;
         }
         /* If we have atomic WCC data, we may update some attributes */
         if ((fattr->valid & NFS_ATTR_WCC) != 0) {
                 if (timespec_equal(&inode->i_ctime, &fattr->pre_ctime))
                         memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));
                 if (timespec_equal(&inode->i_mtime, &fattr->pre_mtime)) {
                         memcpy(&inode->i_mtime, &fattr->mtime, sizeof(inode->i_mtime));
                         if (S_ISDIR(inode->i_mode))
                                 nfsi->cache_validity |= NFS_INO_INVALID_DATA;
                 }
                 if (i_size_read(inode) == nfs_size_to_loff_t(fattr->pre_size) &&
                     nfsi->npages == 0)
                         i_size_write(inode, nfs_size_to_loff_t(fattr->size));
         }
 }
 
 /**
  * nfs_check_inode_attributes - verify consistency of the inode attribute cache
  * @inode - pointer to inode
  * @fattr - updated attributes
  *
  * Verifies the attribute cache. If we have just changed the attributes,
  * so that fattr carries weak cache consistency data, then it may
  * also update the ctime/mtime/change_attribute.
  */
 static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fattr)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
         loff_t cur_size, new_isize;
         unsigned long invalid = 0;
 
 
         /* Has the inode gone and changed behind our back? */
         if (nfsi->fileid != fattr->fileid
                         || (inode->i_mode & S_IFMT) != (fattr->mode & S_IFMT)) {
                 return -EIO;
         }
 
         if ((fattr->valid & NFS_ATTR_FATTR_V4) != 0 &&
                         nfsi->change_attr != fattr->change_attr)
                 invalid |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
 
         /* Verify a few of the more important attributes */
         if (!timespec_equal(&inode->i_mtime, &fattr->mtime))
                 invalid |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
 
         cur_size = i_size_read(inode);
          new_isize = nfs_size_to_loff_t(fattr->size);
         if (cur_size != new_isize && nfsi->npages == 0)
                 invalid |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
 
         /* Have any file permissions changed? */
         if ((inode->i_mode & S_IALLUGO) != (fattr->mode & S_IALLUGO)
                         || inode->i_uid != fattr->uid
                         || inode->i_gid != fattr->gid)
                 invalid |= NFS_INO_INVALID_ATTR | NFS_INO_INVALID_ACCESS | NFS_INO_INVALID_ACL;
 
         /* Has the link count changed? */
         if (inode->i_nlink != fattr->nlink)
                 invalid |= NFS_INO_INVALID_ATTR;
 
         if (!timespec_equal(&inode->i_atime, &fattr->atime))
                 invalid |= NFS_INO_INVALID_ATIME;
 
         if (invalid != 0)
                 nfsi->cache_validity |= invalid;
 
         nfsi->read_cache_jiffies = fattr->time_start;
         return 0;
 }
 
 static int nfs_ctime_need_update(const struct inode *inode, const struct nfs_fattr *fattr)
 {
         return timespec_compare(&fattr->ctime, &inode->i_ctime) > 0;
 }
 
 static int nfs_size_need_update(const struct inode *inode, const struct nfs_fattr *fattr)
 {
         return nfs_size_to_loff_t(fattr->size) > i_size_read(inode);
 }
 
 static atomic_long_t nfs_attr_generation_counter;
 
 static unsigned long nfs_read_attr_generation_counter(void)
 {
         return atomic_long_read(&nfs_attr_generation_counter);
 }
 
 unsigned long nfs_inc_attr_generation_counter(void)
 {
         return atomic_long_inc_return(&nfs_attr_generation_counter);
 }
 
 void nfs_fattr_init(struct nfs_fattr *fattr)
 {
         fattr->valid = 0;
         fattr->time_start = jiffies;
         fattr->gencount = nfs_inc_attr_generation_counter();
 }
 
 /**
  * nfs_inode_attrs_need_update - check if the inode attributes need updating
  * @inode - pointer to inode
  * @fattr - attributes
  *
  * Attempt to divine whether or not an RPC call reply carrying stale
  * attributes got scheduled after another call carrying updated ones.
  *
  * To do so, the function first assumes that a more recent ctime means
  * that the attributes in fattr are newer, however it also attempt to
  * catch the case where ctime either didn't change, or went backwards
  * (if someone reset the clock on the server) by looking at whether
  * or not this RPC call was started after the inode was last updated.
  * Note also the check for wraparound of 'attr_gencount'
  *
  * The function returns 'true' if it thinks the attributes in 'fattr' are
  * more recent than the ones cached in the inode.
  *
  */
 static int nfs_inode_attrs_need_update(const struct inode *inode, const struct nfs_fattr *fattr)
 {
         const struct nfs_inode *nfsi = NFS_I(inode);
 
         return ((long)fattr->gencount - (long)nfsi->attr_gencount) > 0 ||
                 nfs_ctime_need_update(inode, fattr) ||
                 nfs_size_need_update(inode, fattr) ||
                 ((long)nfsi->attr_gencount - (long)nfs_read_attr_generation_counter() > 0);
 }
 
 static int nfs_refresh_inode_locked(struct inode *inode, struct nfs_fattr *fattr)
 {
         if (nfs_inode_attrs_need_update(inode, fattr))
                 return nfs_update_inode(inode, fattr);
         return nfs_check_inode_attributes(inode, fattr);
 }
 
 /**
  * nfs_refresh_inode - try to update the inode attribute cache
  * @inode - pointer to inode
  * @fattr - updated attributes
  *
  * Check that an RPC call that returned attributes has not overlapped with
  * other recent updates of the inode metadata, then decide whether it is
  * safe to do a full update of the inode attributes, or whether just to
  * call nfs_check_inode_attributes.
  */
 int nfs_refresh_inode(struct inode *inode, struct nfs_fattr *fattr)
 {
         int status;
 
         if ((fattr->valid & NFS_ATTR_FATTR) == 0)
                 return 0;
         spin_lock(&inode->i_lock);
         status = nfs_refresh_inode_locked(inode, fattr);
         spin_unlock(&inode->i_lock);
         return status;
 }
 
 static int nfs_post_op_update_inode_locked(struct inode *inode, struct nfs_fattr *fattr)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
 
         nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
         if (S_ISDIR(inode->i_mode))
                 nfsi->cache_validity |= NFS_INO_INVALID_DATA;
         if ((fattr->valid & NFS_ATTR_FATTR) == 0)
                 return 0;
         return nfs_refresh_inode_locked(inode, fattr);
 }
 
/**
 * nfs_post_op_update_inode - try to update the inode attribute cache
 * @inode - pointer to inode
 * @fattr - updated attributes
 *
 * After an operation that has changed the inode metadata, mark the
 * attribute cache as being invalid, then try to update it.
 *
 * NB: if the server didn't return any post op attributes, this
 * function will force the retrieval of attributes before the next
 * NFS request.  Thus it should be used only for operations that
 * are expected to change one or more attributes, to avoid
 * unnecessary NFS requests and trips through nfs_update_inode().
 */
int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr)
{
        int status;

        spin_lock(&inode->i_lock);
        status = nfs_post_op_update_inode_locked(inode, fattr);
        spin_unlock(&inode->i_lock);
        return status;
}

/**
 * nfs_post_op_update_inode_force_wcc - try to update the inode attribute cache
 * @inode - pointer to inode
 * @fattr - updated attributes
 *
 * After an operation that has changed the inode metadata, mark the
 * attribute cache as being invalid, then try to update it. Fake up
 * weak cache consistency data, if none exist.
 *
 * This function is mainly designed to be used by the ->write_done() functions.
 */
int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr)
{
        int status;

        spin_lock(&inode->i_lock);
        /* Don't do a WCC update if these attributes are already stale */
        if ((fattr->valid & NFS_ATTR_FATTR) == 0 ||
                        !nfs_inode_attrs_need_update(inode, fattr)) {
                fattr->valid &= ~(NFS_ATTR_WCC_V4|NFS_ATTR_WCC);
                goto out_noforce;
        }
        if ((fattr->valid & NFS_ATTR_FATTR_V4) != 0 &&
                        (fattr->valid & NFS_ATTR_WCC_V4) == 0) {
                fattr->pre_change_attr = NFS_I(inode)->change_attr;
                fattr->valid |= NFS_ATTR_WCC_V4;
        }
        if ((fattr->valid & NFS_ATTR_FATTR) != 0 &&
                        (fattr->valid & NFS_ATTR_WCC) == 0) {
                memcpy(&fattr->pre_ctime, &inode->i_ctime, sizeof(fattr->pre_ctime));
                memcpy(&fattr->pre_mtime, &inode->i_mtime, sizeof(fattr->pre_mtime));
                fattr->pre_size = i_size_read(inode);
                fattr->valid |= NFS_ATTR_WCC;
        }
out_noforce:
        status = nfs_post_op_update_inode_locked(inode, fattr);
        spin_unlock(&inode->i_lock);
        return status;
}

/*
 * Many nfs protocol calls return the new file attributes after
 * an operation.  Here we update the inode to reflect the state
 * of the server's inode.
 *
 * This is a bit tricky because we have to make sure all dirty pages
 * have been sent off to the server before calling invalidate_inode_pages.
 * To make sure no other process adds more write requests while we try
 * our best to flush them, we make them sleep during the attribute refresh.
 *
 * A very similar scenario holds for the dir cache.
 */
static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
{
        struct nfs_server *server;
        struct nfs_inode *nfsi = NFS_I(inode);
        loff_t cur_isize, new_isize;
        unsigned long invalid = 0;
        unsigned long now = jiffies;

        dfprintk(VFS, "NFS: %s(%s/%ld ct=%d info=0x%x)\n",
                        __func__, inode->i_sb->s_id, inode->i_ino,
                        atomic_read(&inode->i_count), fattr->valid);

        if (nfsi->fileid != fattr->fileid)
                goto out_fileid;

        /*
         * Make sure the inode's type hasn't changed.
         */
        if ((inode->i_mode & S_IFMT) != (fattr->mode & S_IFMT))
                goto out_changed;

        server = NFS_SERVER(inode);
        /* Update the fsid? */
        if (S_ISDIR(inode->i_mode) &&
                        !nfs_fsid_equal(&server->fsid, &fattr->fsid) &&
                        !test_bit(NFS_INO_MOUNTPOINT, &nfsi->flags))
                server->fsid = fattr->fsid;

        /*
         * Update the read time so we don't revalidate too often.
         */
        nfsi->read_cache_jiffies = fattr->time_start;

        nfsi->cache_validity &= ~(NFS_INO_INVALID_ATTR | NFS_INO_INVALID_ATIME
                        | NFS_INO_REVAL_PAGECACHE);

        /* Do atomic weak cache consistency updates */
        nfs_wcc_update_inode(inode, fattr);

        /* More cache consistency checks */
        if (!(fattr->valid & NFS_ATTR_FATTR_V4)) {
                /* NFSv2/v3: Check if the mtime agrees */
                if (!timespec_equal(&inode->i_mtime, &fattr->mtime)) {
                        dprintk("NFS: mtime change on server for file %s/%ld\n",
                                        inode->i_sb->s_id, inode->i_ino);
                        invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;
                        if (S_ISDIR(inode->i_mode))
                                nfs_force_lookup_revalidate(inode);
                }
                /* If ctime has changed we should definitely clear access+acl caches */
                if (!timespec_equal(&inode->i_ctime, &fattr->ctime))
                        invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
        } else if (nfsi->change_attr != fattr->change_attr) {
                dprintk("NFS: change_attr change on server for file %s/%ld\n",
                                inode->i_sb->s_id, inode->i_ino);
                invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
                if (S_ISDIR(inode->i_mode))
                        nfs_force_lookup_revalidate(inode);
        }

        /* Check if our cached file size is stale */
         new_isize = nfs_size_to_loff_t(fattr->size);
        cur_isize = i_size_read(inode);
        if (new_isize != cur_isize) {
                /* Do we perhaps have any outstanding writes, or has
                 * the file grown beyond our last write? */
                if (nfsi->npages == 0 || new_isize > cur_isize) {
                        i_size_write(inode, new_isize);
                        invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;
                }
                dprintk("NFS: isize change on server for file %s/%ld\n",
                                inode->i_sb->s_id, inode->i_ino);
        }


        memcpy(&inode->i_mtime, &fattr->mtime, sizeof(inode->i_mtime));
        memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));
        memcpy(&inode->i_atime, &fattr->atime, sizeof(inode->i_atime));
        nfsi->change_attr = fattr->change_attr;

        if ((inode->i_mode & S_IALLUGO) != (fattr->mode & S_IALLUGO) ||
            inode->i_uid != fattr->uid ||
            inode->i_gid != fattr->gid)
                invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;

        if (inode->i_nlink != fattr->nlink)
                invalid |= NFS_INO_INVALID_ATTR;

        inode->i_mode = fattr->mode;
        inode->i_nlink = fattr->nlink;
        inode->i_uid = fattr->uid;
        inode->i_gid = fattr->gid;

        if (fattr->valid & (NFS_ATTR_FATTR_V3 | NFS_ATTR_FATTR_V4)) {
                /*
                 * report the blocks in 512byte units
                 */
                inode->i_blocks = nfs_calc_block_size(fattr->du.nfs3.used);
         } else {
                 inode->i_blocks = fattr->du.nfs2.blocks;
         }

        /* Update attrtimeo value if we're out of the unstable period */
        if (invalid & NFS_INO_INVALID_ATTR) {
                nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);
                nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
                nfsi->attrtimeo_timestamp = now;
                nfsi->attr_gencount = nfs_inc_attr_generation_counter();
        } else {
                if (!time_in_range(now, nfsi->attrtimeo_timestamp, nfsi->attrtimeo_timestamp + nfsi->attrtimeo)) {
                        if ((nfsi->attrtimeo <<= 1) > NFS_MAXATTRTIMEO(inode))
                                nfsi->attrtimeo = NFS_MAXATTRTIMEO(inode);
                        nfsi->attrtimeo_timestamp = now;
                }
        }
        invalid &= ~NFS_INO_INVALID_ATTR;
        /* Don't invalidate the data if we were to blame */
        if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
                                || S_ISLNK(inode->i_mode)))
                invalid &= ~NFS_INO_INVALID_DATA;
        if (!nfs_have_delegation(inode, FMODE_READ) ||
                        (nfsi->cache_validity & NFS_INO_REVAL_FORCED))
                nfsi->cache_validity |= invalid;
        nfsi->cache_validity &= ~NFS_INO_REVAL_FORCED;

        return 0;
 out_changed:
        /*
         * Big trouble! The inode has become a different object.
         */
        printk(KERN_DEBUG "%s: inode %ld mode changed, %07o to %07o\n",
                        __func__, inode->i_ino, inode->i_mode, fattr->mode);
 out_err:
        /*
         * No need to worry about unhashing the dentry, as the
         * lookup validation will know that the inode is bad.
         * (But we fall through to invalidate the caches.)
         */
        nfs_invalidate_inode(inode);
        return -ESTALE;

 out_fileid:
        printk(KERN_ERR "NFS: server %s error: fileid changed\n"
                "fsid %s: expected fileid 0x%Lx, got 0x%Lx\n",
                NFS_SERVER(inode)->nfs_client->cl_hostname, inode->i_sb->s_id,
                (long long)nfsi->fileid, (long long)fattr->fileid);
        goto out_err;
}


#ifdef CONFIG_NFS_V4

/*
 * Clean out any remaining NFSv4 state that might be left over due
 * to open() calls that passed nfs_atomic_lookup, but failed to call
 * nfs_open().
 */
void nfs4_clear_inode(struct inode *inode)
{
        /* If we are holding a delegation, return it! */
        nfs_inode_return_delegation_noreclaim(inode);
        /* First call standard NFS clear_inode() code */
        nfs_clear_inode(inode);
}
#endif

struct inode *nfs_alloc_inode(struct super_block *sb)
{
        struct nfs_inode *nfsi;
        nfsi = (struct nfs_inode *)kmem_cache_alloc(nfs_inode_cachep, GFP_KERNEL);
        if (!nfsi)
                return NULL;
        nfsi->flags = 0UL;
        nfsi->cache_validity = 0UL;
#ifdef CONFIG_NFS_V3_ACL
        nfsi->acl_access = ERR_PTR(-EAGAIN);
        nfsi->acl_default = ERR_PTR(-EAGAIN);
#endif
#ifdef CONFIG_NFS_V4
        nfsi->nfs4_acl = NULL;
#endif /* CONFIG_NFS_V4 */
        return &nfsi->vfs_inode;
}

void nfs_destroy_inode(struct inode *inode)
{
        kmem_cache_free(nfs_inode_cachep, NFS_I(inode));
}

static inline void nfs4_init_once(struct nfs_inode *nfsi)
{
#ifdef CONFIG_NFS_V4
        INIT_LIST_HEAD(&nfsi->open_states);
        nfsi->delegation = NULL;
        nfsi->delegation_state = 0;
        init_rwsem(&nfsi->rwsem);
#endif
}

static void init_once(void *foo)
{
        struct nfs_inode *nfsi = (struct nfs_inode *) foo;

        inode_init_once(&nfsi->vfs_inode);
        INIT_LIST_HEAD(&nfsi->open_files);
        INIT_LIST_HEAD(&nfsi->access_cache_entry_lru);
        INIT_LIST_HEAD(&nfsi->access_cache_inode_lru);
        INIT_RADIX_TREE(&nfsi->nfs_page_tree, GFP_ATOMIC);
        nfsi->ncommit = 0;
        nfsi->npages = 0;
        atomic_set(&nfsi->silly_count, 1);
        INIT_HLIST_HEAD(&nfsi->silly_list);
        init_waitqueue_head(&nfsi->waitqueue);
        nfs4_init_once(nfsi);
}

static int __init nfs_init_inodecache(void)
{
        nfs_inode_cachep = kmem_cache_create("nfs_inode_cache",
                                             sizeof(struct nfs_inode),
                                             0, (SLAB_RECLAIM_ACCOUNT|
                                                SLAB_MEM_SPREAD),
                                             init_once);
        if (nfs_inode_cachep == NULL)
                return -ENOMEM;

        return 0;
}

static void nfs_destroy_inodecache(void)
{
        kmem_cache_destroy(nfs_inode_cachep);
}

struct workqueue_struct *nfsiod_workqueue;

/*
 * start up the nfsiod workqueue
 */
static int nfsiod_start(void)
{
        struct workqueue_struct *wq;
        dprintk("RPC:       creating workqueue nfsiod\n");
        wq = create_singlethread_workqueue("nfsiod");
        if (wq == NULL)
                return -ENOMEM;
        nfsiod_workqueue = wq;
        return 0;
}

/*
 * Destroy the nfsiod workqueue
 */
static void nfsiod_stop(void)
{
        struct workqueue_struct *wq;

        wq = nfsiod_workqueue;
        if (wq == NULL)
                return;
        nfsiod_workqueue = NULL;
        destroy_workqueue(wq);
}

/*
 * Initialize NFS
 */
static int __init init_nfs_fs(void)
{
        int err;

        err = nfsiod_start();
        if (err)
                goto out6;

        err = nfs_fs_proc_init();
        if (err)
                goto out5;

        err = nfs_init_nfspagecache();
        if (err)
                goto out4;

        err = nfs_init_inodecache();
        if (err)
                goto out3;

        err = nfs_init_readpagecache();
        if (err)
                goto out2;

        err = nfs_init_writepagecache();
        if (err)
                goto out1;

        err = nfs_init_directcache();
        if (err)
                goto out0;

#ifdef CONFIG_PROC_FS
        rpc_proc_register(&nfs_rpcstat);
#endif
        if ((err = register_nfs_fs()) != 0)
                goto out;
        return 0;
out:
#ifdef CONFIG_PROC_FS
        rpc_proc_unregister("nfs");
#endif
        nfs_destroy_directcache();
out0:
        nfs_destroy_writepagecache();
out1:
        nfs_destroy_readpagecache();
out2:
        nfs_destroy_inodecache();
out3:
        nfs_destroy_nfspagecache();
out4:
        nfs_fs_proc_exit();
out5:
        nfsiod_stop();
out6:
        return err;
}

static void __exit exit_nfs_fs(void)
{
        nfs_destroy_directcache();
        nfs_destroy_writepagecache();
        nfs_destroy_readpagecache();
        nfs_destroy_inodecache();
        nfs_destroy_nfspagecache();
#ifdef CONFIG_PROC_FS
        rpc_proc_unregister("nfs");
#endif
        unregister_nfs_fs();
        nfs_fs_proc_exit();
        nfsiod_stop();
}

/* Not quite true; I just maintain it */
MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
MODULE_LICENSE("GPL");
module_param(enable_ino64, bool, 0644);

module_init(init_nfs_fs)
module_exit(exit_nfs_fs)