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inode.c

/*
 *  linux/fs/nfs/inode.c
 *
 *  Copyright (C) 1992  Rick Sladkey
 *
 *  nfs inode and superblock handling functions
 *
 *  Modularised by Alan Cox <Alan.Cox@linux.org>, 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 void nfs_zap_acl_cache(struct inode *);

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);
      }
}

static 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_FLAGS(inode));
      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;

      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_FLAGS(inode));
                  /* 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;
                  }
            } 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->last_updated = now;
            nfsi->cache_change_attribute = now;
            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)

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 == 0)
            return 0;

      lock_kernel();
      /* 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);
      unlock_kernel();
      return error;
}

/**
 * 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) {
            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;
            spin_lock(&inode->i_lock);
            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);
            inode->i_size = attr->ia_size;
            vmtruncate(inode, attr->ia_size);
      }
}

static int nfs_wait_schedule(void *word)
{
      if (signal_pending(current))
            return -ERESTARTSYS;
      schedule();
      return 0;
}

/*
 * Wait for the inode to get unlocked.
 */
static int nfs_wait_on_inode(struct inode *inode)
{
      struct rpc_clnt   *clnt = NFS_CLIENT(inode);
      struct nfs_inode *nfsi = NFS_I(inode);
      sigset_t oldmask;
      int error;

      rpc_clnt_sigmask(clnt, &oldmask);
      error = wait_on_bit_lock(&nfsi->flags, NFS_INO_REVALIDATING,
                              nfs_wait_schedule, TASK_INTERRUPTIBLE);
      rpc_clnt_sigunmask(clnt, &oldmask);

      return error;
}

static void nfs_wake_up_inode(struct inode *inode)
{
      struct nfs_inode *nfsi = NFS_I(inode);

      clear_bit(NFS_INO_REVALIDATING, &nfsi->flags);
      smp_mb__after_clear_bit();
      wake_up_bit(&nfsi->flags, NFS_INO_REVALIDATING);
}

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 */
      if (S_ISREG(inode->i_mode))
            nfs_wb_nocommit(inode);

      /*
       * 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->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 = 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);
      dput(ctx->path.dentry);
      mntput(ctx->path.mnt);
      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 = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0);
      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));

      nfs_inc_stats(inode, NFSIOS_INODEREVALIDATE);
      lock_kernel();
      if (is_bad_inode(inode))
            goto out_nowait;
      if (NFS_STALE(inode))
            goto out_nowait;

      status = nfs_wait_on_inode(inode);
      if (status < 0)
            goto out;

      status = -ESTALE;
      if (NFS_STALE(inode))
            goto out;

      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_FLAGS(inode));
            }
            goto out;
      }

      spin_lock(&inode->i_lock);
      status = nfs_update_inode(inode, &fattr);
      if (status) {
            spin_unlock(&inode->i_lock);
            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;
      }
      spin_unlock(&inode->i_lock);

      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:
      nfs_wake_up_inode(inode);

 out_nowait:
      unlock_kernel();
      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;
      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 (inode->i_size == fattr->pre_size && nfsi->npages == 0)
                  inode->i_size = 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;
      }

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

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

      nfsi->read_cache_jiffies = fattr->time_start;
      return 0;
}

/**
 * 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)
{
      struct nfs_inode *nfsi = NFS_I(inode);
      int status;

      if ((fattr->valid & NFS_ATTR_FATTR) == 0)
            return 0;
      spin_lock(&inode->i_lock);
      if (time_after(fattr->time_start, nfsi->last_updated))
            status = nfs_update_inode(inode, fattr);
      else
            status = nfs_check_inode_attributes(inode, fattr);

      spin_unlock(&inode->i_lock);
      return status;
}

/**
 * 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)
{
      struct nfs_inode *nfsi = NFS_I(inode);

      spin_lock(&inode->i_lock);
      nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
      if (S_ISDIR(inode->i_mode))
            nfsi->cache_validity |= NFS_INO_INVALID_DATA;
      spin_unlock(&inode->i_lock);
      return nfs_refresh_inode(inode, fattr);
}

/**
 * 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)
{
      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 = inode->i_size;
            fattr->valid |= NFS_ATTR_WCC;
      }
      return nfs_post_op_update_inode(inode, fattr);
}

/*
 * 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",
                  __FUNCTION__, 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))
            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;
                  nfsi->cache_change_attribute = now;
            }
            /* If ctime has changed we should definitely clear access+acl caches */
            if (!timespec_equal(&inode->i_ctime, &fattr->ctime))
                  invalid |= 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;
            nfsi->cache_change_attribute = now;
      }

      /* 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) {
                  inode->i_size = 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;

      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->last_updated = now;
      } 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;
            }
            /*
             * Avoid jiffy wraparound issues with nfsi->last_updated
             */
            if (!time_in_range(nfsi->last_updated, nfsi->read_cache_jiffies, now))
                  nfsi->last_updated = nfsi->read_cache_jiffies;
      }
      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",
                  __FUNCTION__, 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(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(struct kmem_cache * cachep, 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);
}

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

      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:
      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();
}

/* 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)

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