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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *  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/signal.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/seq_file.h>
 #include <linux/mount.h>
 #include <linux/vfs.h>
 #include <linux/inet.h>
 #include <linux/nfs_xdr.h>
 #include <linux/slab.h>
 #include <linux/compat.h>
 #include <linux/freezer.h>
 #include <linux/uaccess.h>
 #include <linux/iversion.h>
 
 #include "nfs4_fs.h"
 #include "callback.h"
 #include "delegation.h"
 #include "iostat.h"
 #include "internal.h"
 #include "fscache.h"
 #include "pnfs.h"
 #include "nfs.h"
 #include "netns.h"
 #include "sysfs.h"
 
 #include "nfstrace.h"
 
 #define NFSDBG_FACILITY     NFSDBG_VFS
 
 #define NFS_64_BIT_INODE_NUMBERS_ENABLED    1
 
 /* Default is to see 64-bit inode numbers */
 static bool enable_ino64 = NFS_64_BIT_INODE_NUMBERS_ENABLED;
 
 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);
 }
 
 static int nfs_wait_killable(int mode)
 {
     freezable_schedule_unsafe();
     if (signal_pending_state(mode, current))
         return -ERESTARTSYS;
     return 0;
 }
 
 int nfs_wait_bit_killable(struct wait_bit_key *key, int mode)
 {
     return nfs_wait_killable(mode);
 }
 EXPORT_SYMBOL_GPL(nfs_wait_bit_killable);
 
 /**
  * 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)
 {
 #ifdef CONFIG_COMPAT
     compat_ulong_t ino;
 #else   
     unsigned long ino;
 #endif
 
     if (enable_ino64)
         return fileid;
     ino = fileid;
     if (sizeof(ino) < sizeof(fileid))
         ino ^= fileid >> (sizeof(fileid)-sizeof(ino)) * 8;
     return ino;
 }
 
 int nfs_drop_inode(struct inode *inode)
 {
     return NFS_STALE(inode) || generic_drop_inode(inode);
 }
 EXPORT_SYMBOL_GPL(nfs_drop_inode);
 
 void nfs_clear_inode(struct inode *inode)
 {
     /*
      * The following should never happen...
      */
     WARN_ON_ONCE(nfs_have_writebacks(inode));
     WARN_ON_ONCE(!list_empty(&NFS_I(inode)->open_files));
     nfs_zap_acl_cache(inode);
     nfs_access_zap_cache(inode);
     nfs_fscache_clear_inode(inode);
 }
 EXPORT_SYMBOL_GPL(nfs_clear_inode);
 
 void nfs_evict_inode(struct inode *inode)
 {
     truncate_inode_pages_final(&inode->i_data);
     clear_inode(inode);
     nfs_clear_inode(inode);
 }
 
 int nfs_sync_inode(struct inode *inode)
 {
     inode_dio_wait(inode);
     return nfs_wb_all(inode);
 }
 EXPORT_SYMBOL_GPL(nfs_sync_inode);
 
 /**
  * nfs_sync_mapping - helper to flush all mmapped dirty data to disk
  * @mapping: pointer to struct address_space
  */
 int nfs_sync_mapping(struct address_space *mapping)
 {
     int ret = 0;
 
     if (mapping->nrpages != 0) {
         unmap_mapping_range(mapping, 0, 0, 0);
         ret = nfs_wb_all(mapping->host);
     }
     return ret;
 }
 
 static int nfs_attribute_timeout(struct inode *inode)
 {
     struct nfs_inode *nfsi = NFS_I(inode);
 
     return !time_in_range_open(jiffies, nfsi->read_cache_jiffies, nfsi->read_cache_jiffies + nfsi->attrtimeo);
 }
 
 static bool nfs_check_cache_flags_invalid(struct inode *inode,
                       unsigned long flags)
 {
     unsigned long cache_validity = READ_ONCE(NFS_I(inode)->cache_validity);
 
     return (cache_validity & flags) != 0;
 }
 
 bool nfs_check_cache_invalid(struct inode *inode, unsigned long flags)
 {
     if (nfs_check_cache_flags_invalid(inode, flags))
         return true;
     return nfs_attribute_cache_expired(inode);
 }
 EXPORT_SYMBOL_GPL(nfs_check_cache_invalid);
 
 #ifdef CONFIG_NFS_V4_2
 static bool nfs_has_xattr_cache(const struct nfs_inode *nfsi)
 {
     return nfsi->xattr_cache != NULL;
 }
 #else
 static bool nfs_has_xattr_cache(const struct nfs_inode *nfsi)
 {
     return false;
 }
 #endif
 
 void nfs_set_cache_invalid(struct inode *inode, unsigned long flags)
 {
     struct nfs_inode *nfsi = NFS_I(inode);
     bool have_delegation = NFS_PROTO(inode)->have_delegation(inode, FMODE_READ);
 
     if (have_delegation) {
         if (!(flags & NFS_INO_REVAL_FORCED))
             flags &= ~(NFS_INO_INVALID_MODE |
                    NFS_INO_INVALID_OTHER |
                    NFS_INO_INVALID_XATTR);
         flags &= ~(NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE);
     }
 
     if (!nfs_has_xattr_cache(nfsi))
         flags &= ~NFS_INO_INVALID_XATTR;
     if (flags & NFS_INO_INVALID_DATA)
         nfs_fscache_invalidate(inode, 0);
     flags &= ~NFS_INO_REVAL_FORCED;
 
     nfsi->cache_validity |= flags;
 
     if (inode->i_mapping->nrpages == 0)
         nfsi->cache_validity &= ~(NFS_INO_INVALID_DATA |
                       NFS_INO_DATA_INVAL_DEFER);
     else if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
         nfsi->cache_validity &= ~NFS_INO_DATA_INVAL_DEFER;
     trace_nfs_set_cache_invalid(inode, 0);
 }
 EXPORT_SYMBOL_GPL(nfs_set_cache_invalid);
 
 /*
  * 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;
 
     if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))
         nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATTR |
                              NFS_INO_INVALID_DATA |
                              NFS_INO_INVALID_ACCESS |
                              NFS_INO_INVALID_ACL |
                              NFS_INO_INVALID_XATTR);
     else
         nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATTR |
                              NFS_INO_INVALID_ACCESS |
                              NFS_INO_INVALID_ACL |
                              NFS_INO_INVALID_XATTR);
     nfs_zap_label_cache_locked(nfsi);
 }
 
 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_set_cache_invalid(inode, 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);
 }
 EXPORT_SYMBOL_GPL(nfs_zap_acl_cache);
 
 void nfs_invalidate_atime(struct inode *inode)
 {
     spin_lock(&inode->i_lock);
     nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATIME);
     spin_unlock(&inode->i_lock);
 }
 EXPORT_SYMBOL_GPL(nfs_invalidate_atime);
 
 /*
  * Invalidate, but do not unhash, the inode.
  * NB: must be called with inode->i_lock held!
  */
 static void nfs_set_inode_stale_locked(struct inode *inode)
 {
     set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
     nfs_zap_caches_locked(inode);
     trace_nfs_set_inode_stale(inode);
 }
 
 void nfs_set_inode_stale(struct inode *inode)
 {
     spin_lock(&inode->i_lock);
     nfs_set_inode_stale_locked(inode);
     spin_unlock(&inode->i_lock);
 }
 
 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 (inode_wrong_type(inode, fattr->mode))
         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);
     inode->i_mode = fattr->mode;
     nfs_copy_fh(NFS_FH(inode), desc->fh);
     return 0;
 }
 
 #ifdef CONFIG_NFS_V4_SECURITY_LABEL
 static void nfs_clear_label_invalid(struct inode *inode)
 {
     spin_lock(&inode->i_lock);
     NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_LABEL;
     spin_unlock(&inode->i_lock);
 }
 
 void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr)
 {
     int error;
 
     if (fattr->label == NULL)
         return;
 
     if ((fattr->valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL) && inode->i_security) {
         error = security_inode_notifysecctx(inode, fattr->label->label,
                 fattr->label->len);
         if (error)
             printk(KERN_ERR "%s() %s %d "
                     "security_inode_notifysecctx() %d\n",
                     __func__,
                     (char *)fattr->label->label,
                     fattr->label->len, error);
         nfs_clear_label_invalid(inode);
     }
 }
 
 struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags)
 {
     struct nfs4_label *label;
 
     if (!(server->caps & NFS_CAP_SECURITY_LABEL))
         return NULL;
 
     label = kzalloc(sizeof(struct nfs4_label), flags);
     if (label == NULL)
         return ERR_PTR(-ENOMEM);
 
     label->label = kzalloc(NFS4_MAXLABELLEN, flags);
     if (label->label == NULL) {
         kfree(label);
         return ERR_PTR(-ENOMEM);
     }
     label->len = NFS4_MAXLABELLEN;
 
     return label;
 }
 EXPORT_SYMBOL_GPL(nfs4_label_alloc);
 #else
 void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr)
 {
 }
 #endif
 EXPORT_SYMBOL_GPL(nfs_setsecurity);
 
 /* Search for inode identified by fh, fileid and i_mode in inode cache. */
 struct inode *
 nfs_ilookup(struct super_block *sb, struct nfs_fattr *fattr, struct nfs_fh *fh)
 {
     struct nfs_find_desc desc = {
         .fh = fh,
         .fattr  = fattr,
     };
     struct inode *inode;
     unsigned long hash;
 
     if (!(fattr->valid & NFS_ATTR_FATTR_FILEID) ||
         !(fattr->valid & NFS_ATTR_FATTR_TYPE))
         return NULL;
 
     hash = nfs_fattr_to_ino_t(fattr);
     inode = ilookup5(sb, hash, nfs_find_actor, &desc);
 
     dprintk("%s: returning %p\n", __func__, inode);
     return inode;
 }
 
 static void nfs_inode_init_regular(struct nfs_inode *nfsi)
 {
     atomic_long_set(&nfsi->nrequests, 0);
     atomic_long_set(&nfsi->redirtied_pages, 0);
     INIT_LIST_HEAD(&nfsi->commit_info.list);
     atomic_long_set(&nfsi->commit_info.ncommit, 0);
     atomic_set(&nfsi->commit_info.rpcs_out, 0);
     mutex_init(&nfsi->commit_mutex);
 }
 
 static void nfs_inode_init_dir(struct nfs_inode *nfsi)
 {
     nfsi->cache_change_attribute = 0;
     memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
     init_rwsem(&nfsi->rmdir_sem);
 }
 
 /*
  * 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);
     u64 fattr_supported = NFS_SB(sb)->fattr_valid;
     unsigned long hash;
 
     nfs_attr_check_mountpoint(sb, fattr);
 
     if (nfs_attr_use_mounted_on_fileid(fattr))
         fattr->fileid = fattr->mounted_on_fileid;
     else if ((fattr->valid & NFS_ATTR_FATTR_FILEID) == 0)
         goto out_no_inode;
     if ((fattr->valid & NFS_ATTR_FATTR_TYPE) == 0)
         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;
         nfsi->cache_validity = 0;
         if ((fattr->valid & NFS_ATTR_FATTR_MODE) == 0
                 && (fattr_supported & NFS_ATTR_FATTR_MODE))
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_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_SB(sb)->nfs_client->rpc_ops->file_ops;
             inode->i_data.a_ops = &nfs_file_aops;
             nfs_inode_init_regular(nfsi);
         } 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;
             inode->i_data.a_ops = &nfs_dir_aops;
             nfs_inode_init_dir(nfsi);
             /* Deal with crossing mountpoints */
             if (fattr->valid & NFS_ATTR_FATTR_MOUNTPOINT ||
                     fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
                 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;
                 inode->i_flags |= S_AUTOMOUNT;
             }
         } else if (S_ISLNK(inode->i_mode)) {
             inode->i_op = &nfs_symlink_inode_operations;
             inode_nohighmem(inode);
         } else
             init_special_inode(inode, inode->i_mode, fattr->rdev);
 
         memset(&inode->i_atime, 0, sizeof(inode->i_atime));
         memset(&inode->i_mtime, 0, sizeof(inode->i_mtime));
         memset(&inode->i_ctime, 0, sizeof(inode->i_ctime));
         inode_set_iversion_raw(inode, 0);
         inode->i_size = 0;
         clear_nlink(inode);
         inode->i_uid = make_kuid(&init_user_ns, -2);
         inode->i_gid = make_kgid(&init_user_ns, -2);
         inode->i_blocks = 0;
         nfsi->write_io = 0;
         nfsi->read_io = 0;
 
         nfsi->read_cache_jiffies = fattr->time_start;
         nfsi->attr_gencount = fattr->gencount;
         if (fattr->valid & NFS_ATTR_FATTR_ATIME)
             inode->i_atime = fattr->atime;
         else if (fattr_supported & NFS_ATTR_FATTR_ATIME)
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATIME);
         if (fattr->valid & NFS_ATTR_FATTR_MTIME)
             inode->i_mtime = fattr->mtime;
         else if (fattr_supported & NFS_ATTR_FATTR_MTIME)
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_MTIME);
         if (fattr->valid & NFS_ATTR_FATTR_CTIME)
             inode->i_ctime = fattr->ctime;
         else if (fattr_supported & NFS_ATTR_FATTR_CTIME)
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_CTIME);
         if (fattr->valid & NFS_ATTR_FATTR_CHANGE)
             inode_set_iversion_raw(inode, fattr->change_attr);
         else
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE);
         if (fattr->valid & NFS_ATTR_FATTR_SIZE)
             inode->i_size = nfs_size_to_loff_t(fattr->size);
         else
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_SIZE);
         if (fattr->valid & NFS_ATTR_FATTR_NLINK)
             set_nlink(inode, fattr->nlink);
         else if (fattr_supported & NFS_ATTR_FATTR_NLINK)
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_NLINK);
         if (fattr->valid & NFS_ATTR_FATTR_OWNER)
             inode->i_uid = fattr->uid;
         else if (fattr_supported & NFS_ATTR_FATTR_OWNER)
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_OTHER);
         if (fattr->valid & NFS_ATTR_FATTR_GROUP)
             inode->i_gid = fattr->gid;
         else if (fattr_supported & NFS_ATTR_FATTR_GROUP)
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_OTHER);
         if (fattr->valid & NFS_ATTR_FATTR_BLOCKS_USED)
             inode->i_blocks = fattr->du.nfs2.blocks;
         else if (fattr_supported & NFS_ATTR_FATTR_BLOCKS_USED &&
              fattr->size != 0)
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_BLOCKS);
         if (fattr->valid & NFS_ATTR_FATTR_SPACE_USED) {
             /*
              * report the blocks in 512byte units
              */
             inode->i_blocks = nfs_calc_block_size(fattr->du.nfs3.used);
         } else if (fattr_supported & NFS_ATTR_FATTR_SPACE_USED &&
                fattr->size != 0)
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_BLOCKS);
 
         nfs_setsecurity(inode, fattr);
 
         nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
         nfsi->attrtimeo_timestamp = now;
         nfsi->access_cache = RB_ROOT;
 
         nfs_fscache_init_inode(inode);
 
         unlock_new_inode(inode);
     } else {
         int err = nfs_refresh_inode(inode, fattr);
         if (err < 0) {
             iput(inode);
             inode = ERR_PTR(err);
             goto out_no_inode;
         }
     }
     dprintk("NFS: nfs_fhget(%s/%Lu fh_crc=0x%08x ct=%d)\n",
         inode->i_sb->s_id,
         (unsigned long long)NFS_FILEID(inode),
         nfs_display_fhandle_hash(fh),
         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;
 }
 EXPORT_SYMBOL_GPL(nfs_fhget);
 
 #define NFS_VALID_ATTRS (ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_SIZE|ATTR_ATIME|ATTR_ATIME_SET|ATTR_MTIME|ATTR_MTIME_SET|ATTR_FILE|ATTR_OPEN)
 
 int
 nfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
         struct iattr *attr)
 {
     struct inode *inode = d_inode(dentry);
     struct nfs_fattr *fattr;
     int error = 0;
 
     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) {
         BUG_ON(!S_ISREG(inode->i_mode));
 
         error = inode_newsize_ok(inode, attr->ia_size);
         if (error)
             return error;
 
         if (attr->ia_size == i_size_read(inode))
             attr->ia_valid &= ~ATTR_SIZE;
     }
 
     /* Optimization: if the end result is no change, don't RPC */
     if (((attr->ia_valid & NFS_VALID_ATTRS) & ~(ATTR_FILE|ATTR_OPEN)) == 0)
         return 0;
 
     trace_nfs_setattr_enter(inode);
 
     /* Write all dirty data */
     if (S_ISREG(inode->i_mode))
         nfs_sync_inode(inode);
 
     fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode));
     if (fattr == NULL) {
         error = -ENOMEM;
         goto out;
     }
 
     error = NFS_PROTO(inode)->setattr(dentry, fattr, attr);
     if (error == 0)
         error = nfs_refresh_inode(inode, fattr);
     nfs_free_fattr(fattr);
 out:
     trace_nfs_setattr_exit(inode, error);
     return error;
 }
 EXPORT_SYMBOL_GPL(nfs_setattr);
 
 /**
  * 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.
  * Note: must be called with inode->i_lock held!
  */
 static int nfs_vmtruncate(struct inode * inode, loff_t offset)
 {
     int err;
 
     err = inode_newsize_ok(inode, offset);
     if (err)
         goto out;
 
     trace_nfs_size_truncate(inode, offset);
     i_size_write(inode, offset);
     /* Optimisation */
     if (offset == 0)
         NFS_I(inode)->cache_validity &= ~(NFS_INO_INVALID_DATA |
                 NFS_INO_DATA_INVAL_DEFER);
     NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;
 
     spin_unlock(&inode->i_lock);
     truncate_pagecache(inode, offset);
     spin_lock(&inode->i_lock);
 out:
     return err;
 }
 
 /**
  * nfs_setattr_update_inode - Update inode metadata after a setattr call.
  * @inode: pointer to struct inode
  * @attr: pointer to struct iattr
  * @fattr: pointer to struct nfs_fattr
  *
  * 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,
         struct nfs_fattr *fattr)
 {
     /* Barrier: bump the attribute generation count. */
     nfs_fattr_set_barrier(fattr);
 
     spin_lock(&inode->i_lock);
     NFS_I(inode)->attr_gencount = fattr->gencount;
     if ((attr->ia_valid & ATTR_SIZE) != 0) {
         nfs_set_cache_invalid(inode, NFS_INO_INVALID_MTIME |
                              NFS_INO_INVALID_BLOCKS);
         nfs_inc_stats(inode, NFSIOS_SETATTRTRUNC);
         nfs_vmtruncate(inode, attr->ia_size);
     }
     if ((attr->ia_valid & (ATTR_MODE|ATTR_UID|ATTR_GID)) != 0) {
         NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_CTIME;
         if ((attr->ia_valid & ATTR_KILL_SUID) != 0 &&
             inode->i_mode & S_ISUID)
             inode->i_mode &= ~S_ISUID;
         if ((attr->ia_valid & ATTR_KILL_SGID) != 0 &&
             (inode->i_mode & (S_ISGID | S_IXGRP)) ==
              (S_ISGID | S_IXGRP))
             inode->i_mode &= ~S_ISGID;
         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;
         if (fattr->valid & NFS_ATTR_FATTR_CTIME)
             inode->i_ctime = fattr->ctime;
         else
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE
                     | NFS_INO_INVALID_CTIME);
         nfs_set_cache_invalid(inode, NFS_INO_INVALID_ACCESS
                 | NFS_INO_INVALID_ACL);
     }
     if (attr->ia_valid & (ATTR_ATIME_SET|ATTR_ATIME)) {
         NFS_I(inode)->cache_validity &= ~(NFS_INO_INVALID_ATIME
                 | NFS_INO_INVALID_CTIME);
         if (fattr->valid & NFS_ATTR_FATTR_ATIME)
             inode->i_atime = fattr->atime;
         else if (attr->ia_valid & ATTR_ATIME_SET)
             inode->i_atime = attr->ia_atime;
         else
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_ATIME);
 
         if (fattr->valid & NFS_ATTR_FATTR_CTIME)
             inode->i_ctime = fattr->ctime;
         else
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE
                     | NFS_INO_INVALID_CTIME);
     }
     if (attr->ia_valid & (ATTR_MTIME_SET|ATTR_MTIME)) {
         NFS_I(inode)->cache_validity &= ~(NFS_INO_INVALID_MTIME
                 | NFS_INO_INVALID_CTIME);
         if (fattr->valid & NFS_ATTR_FATTR_MTIME)
             inode->i_mtime = fattr->mtime;
         else if (attr->ia_valid & ATTR_MTIME_SET)
             inode->i_mtime = attr->ia_mtime;
         else
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_MTIME);
 
         if (fattr->valid & NFS_ATTR_FATTR_CTIME)
             inode->i_ctime = fattr->ctime;
         else
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_CHANGE
                     | NFS_INO_INVALID_CTIME);
     }
     if (fattr->valid)
         nfs_update_inode(inode, fattr);
     spin_unlock(&inode->i_lock);
 }
 EXPORT_SYMBOL_GPL(nfs_setattr_update_inode);
 
 /*
  * Don't request help from readdirplus if the file is being written to,
  * or if attribute caching is turned off
  */
 static bool nfs_getattr_readdirplus_enable(const struct inode *inode)
 {
     return nfs_server_capable(inode, NFS_CAP_READDIRPLUS) &&
            !nfs_have_writebacks(inode) && NFS_MAXATTRTIMEO(inode) > 5 * HZ;
 }
 
 static void nfs_readdirplus_parent_cache_miss(struct dentry *dentry)
 {
     if (!IS_ROOT(dentry)) {
         struct dentry *parent = dget_parent(dentry);
         nfs_readdir_record_entry_cache_miss(d_inode(parent));
         dput(parent);
     }
 }
 
 static void nfs_readdirplus_parent_cache_hit(struct dentry *dentry)
 {
     if (!IS_ROOT(dentry)) {
         struct dentry *parent = dget_parent(dentry);
         nfs_readdir_record_entry_cache_hit(d_inode(parent));
         dput(parent);
     }
 }
 
 static u32 nfs_get_valid_attrmask(struct inode *inode)
 {
     unsigned long cache_validity = READ_ONCE(NFS_I(inode)->cache_validity);
     u32 reply_mask = STATX_INO | STATX_TYPE;
 
     if (!(cache_validity & NFS_INO_INVALID_ATIME))
         reply_mask |= STATX_ATIME;
     if (!(cache_validity & NFS_INO_INVALID_CTIME))
         reply_mask |= STATX_CTIME;
     if (!(cache_validity & NFS_INO_INVALID_MTIME))
         reply_mask |= STATX_MTIME;
     if (!(cache_validity & NFS_INO_INVALID_SIZE))
         reply_mask |= STATX_SIZE;
     if (!(cache_validity & NFS_INO_INVALID_NLINK))
         reply_mask |= STATX_NLINK;
     if (!(cache_validity & NFS_INO_INVALID_MODE))
         reply_mask |= STATX_MODE;
     if (!(cache_validity & NFS_INO_INVALID_OTHER))
         reply_mask |= STATX_UID | STATX_GID;
     if (!(cache_validity & NFS_INO_INVALID_BLOCKS))
         reply_mask |= STATX_BLOCKS;
     return reply_mask;
 }
 
 int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
         struct kstat *stat, u32 request_mask, unsigned int query_flags)
 {
     struct inode *inode = d_inode(path->dentry);
     struct nfs_server *server = NFS_SERVER(inode);
     unsigned long cache_validity;
     int err = 0;
     bool force_sync = query_flags & AT_STATX_FORCE_SYNC;
     bool do_update = false;
     bool readdirplus_enabled = nfs_getattr_readdirplus_enable(inode);
 
     trace_nfs_getattr_enter(inode);
 
     request_mask &= STATX_TYPE | STATX_MODE | STATX_NLINK | STATX_UID |
             STATX_GID | STATX_ATIME | STATX_MTIME | STATX_CTIME |
             STATX_INO | STATX_SIZE | STATX_BLOCKS;
 
     if ((query_flags & AT_STATX_DONT_SYNC) && !force_sync) {
         if (readdirplus_enabled)
             nfs_readdirplus_parent_cache_hit(path->dentry);
         goto out_no_revalidate;
     }
 
     /* Flush out writes to the server in order to update c/mtime.  */
     if ((request_mask & (STATX_CTIME | STATX_MTIME)) &&
         S_ISREG(inode->i_mode))
         filemap_write_and_wait(inode->i_mapping);
 
     /*
      * 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 SB_NOATIME or SB_NODIRATIME so there is
      *    no point in checking those.
      */
     if ((path->mnt->mnt_flags & MNT_NOATIME) ||
         ((path->mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))
         request_mask &= ~STATX_ATIME;
 
     /* Is the user requesting attributes that might need revalidation? */
     if (!(request_mask & (STATX_MODE|STATX_NLINK|STATX_ATIME|STATX_CTIME|
                     STATX_MTIME|STATX_UID|STATX_GID|
                     STATX_SIZE|STATX_BLOCKS)))
         goto out_no_revalidate;
 
     /* Check whether the cached attributes are stale */
     do_update |= force_sync || nfs_attribute_cache_expired(inode);
     cache_validity = READ_ONCE(NFS_I(inode)->cache_validity);
     do_update |= cache_validity & NFS_INO_INVALID_CHANGE;
     if (request_mask & STATX_ATIME)
         do_update |= cache_validity & NFS_INO_INVALID_ATIME;
     if (request_mask & STATX_CTIME)
         do_update |= cache_validity & NFS_INO_INVALID_CTIME;
     if (request_mask & STATX_MTIME)
         do_update |= cache_validity & NFS_INO_INVALID_MTIME;
     if (request_mask & STATX_SIZE)
         do_update |= cache_validity & NFS_INO_INVALID_SIZE;
     if (request_mask & STATX_NLINK)
         do_update |= cache_validity & NFS_INO_INVALID_NLINK;
     if (request_mask & STATX_MODE)
         do_update |= cache_validity & NFS_INO_INVALID_MODE;
     if (request_mask & (STATX_UID | STATX_GID))
         do_update |= cache_validity & NFS_INO_INVALID_OTHER;
     if (request_mask & STATX_BLOCKS)
         do_update |= cache_validity & NFS_INO_INVALID_BLOCKS;
 
     if (do_update) {
         if (readdirplus_enabled)
             nfs_readdirplus_parent_cache_miss(path->dentry);
         err = __nfs_revalidate_inode(server, inode);
         if (err)
             goto out;
     } else if (readdirplus_enabled)
         nfs_readdirplus_parent_cache_hit(path->dentry);
 out_no_revalidate:
     /* Only return attributes that were revalidated. */
     stat->result_mask = nfs_get_valid_attrmask(inode) | request_mask;
 
     generic_fillattr(&init_user_ns, inode, stat);
     stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
     if (S_ISDIR(inode->i_mode))
         stat->blksize = NFS_SERVER(inode)->dtsize;
 out:
     trace_nfs_getattr_exit(inode, err);
     return err;
 }
 EXPORT_SYMBOL_GPL(nfs_getattr);
 
 static void nfs_init_lock_context(struct nfs_lock_context *l_ctx)
 {
     refcount_set(&l_ctx->count, 1);
     l_ctx->lockowner = current->files;
     INIT_LIST_HEAD(&l_ctx->list);
     atomic_set(&l_ctx->io_count, 0);
 }
 
 static struct nfs_lock_context *__nfs_find_lock_context(struct nfs_open_context *ctx)
 {
     struct nfs_lock_context *pos;
 
     list_for_each_entry_rcu(pos, &ctx->lock_context.list, list) {
         if (pos->lockowner != current->files)
             continue;
         if (refcount_inc_not_zero(&pos->count))
             return pos;
     }
     return NULL;
 }
 
 struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
 {
     struct nfs_lock_context *res, *new = NULL;
     struct inode *inode = d_inode(ctx->dentry);
 
     rcu_read_lock();
     res = __nfs_find_lock_context(ctx);
     rcu_read_unlock();
     if (res == NULL) {
         new = kmalloc(sizeof(*new), GFP_KERNEL_ACCOUNT);
         if (new == NULL)
             return ERR_PTR(-ENOMEM);
         nfs_init_lock_context(new);
         spin_lock(&inode->i_lock);
         res = __nfs_find_lock_context(ctx);
         if (res == NULL) {
             new->open_context = get_nfs_open_context(ctx);
             if (new->open_context) {
                 list_add_tail_rcu(&new->list,
                         &ctx->lock_context.list);
                 res = new;
                 new = NULL;
             } else
                 res = ERR_PTR(-EBADF);
         }
         spin_unlock(&inode->i_lock);
         kfree(new);
     }
     return res;
 }
 EXPORT_SYMBOL_GPL(nfs_get_lock_context);
 
 void nfs_put_lock_context(struct nfs_lock_context *l_ctx)
 {
     struct nfs_open_context *ctx = l_ctx->open_context;
     struct inode *inode = d_inode(ctx->dentry);
 
     if (!refcount_dec_and_lock(&l_ctx->count, &inode->i_lock))
         return;
     list_del_rcu(&l_ctx->list);
     spin_unlock(&inode->i_lock);
     put_nfs_open_context(ctx);
     kfree_rcu(l_ctx, rcu_head);
 }
 EXPORT_SYMBOL_GPL(nfs_put_lock_context);
 
 /**
  * nfs_close_context - Common close_context() routine NFSv2/v3
  * @ctx: pointer to context
  * @is_sync: is this a synchronous close
  *
  * Ensure that the attributes are up to date if we're mounted
  * with close-to-open semantics and we have cached data that will
  * need to be revalidated on open.
  */
 void nfs_close_context(struct nfs_open_context *ctx, int is_sync)
 {
     struct nfs_inode *nfsi;
     struct inode *inode;
 
     if (!(ctx->mode & FMODE_WRITE))
         return;
     if (!is_sync)
         return;
     inode = d_inode(ctx->dentry);
     if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
         return;
     nfsi = NFS_I(inode);
     if (inode->i_mapping->nrpages == 0)
         return;
     if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
         return;
     if (!list_empty(&nfsi->open_files))
         return;
     if (NFS_SERVER(inode)->flags & NFS_MOUNT_NOCTO)
         return;
     nfs_revalidate_inode(inode,
                  NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE);
 }
 EXPORT_SYMBOL_GPL(nfs_close_context);
 
 struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry,
                         fmode_t f_mode,
                         struct file *filp)
 {
     struct nfs_open_context *ctx;
 
     ctx = kmalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
     if (!ctx)
         return ERR_PTR(-ENOMEM);
     nfs_sb_active(dentry->d_sb);
     ctx->dentry = dget(dentry);
     if (filp)
         ctx->cred = get_cred(filp->f_cred);
     else
         ctx->cred = get_current_cred();
     rcu_assign_pointer(ctx->ll_cred, NULL);
     ctx->state = NULL;
     ctx->mode = f_mode;
     ctx->flags = 0;
     ctx->error = 0;
     ctx->flock_owner = (fl_owner_t)filp;
     nfs_init_lock_context(&ctx->lock_context);
     ctx->lock_context.open_context = ctx;
     INIT_LIST_HEAD(&ctx->list);
     ctx->mdsthreshold = NULL;
     return ctx;
 }
 EXPORT_SYMBOL_GPL(alloc_nfs_open_context);
 
 struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx)
 {
     if (ctx != NULL && refcount_inc_not_zero(&ctx->lock_context.count))
         return ctx;
     return NULL;
 }
 EXPORT_SYMBOL_GPL(get_nfs_open_context);
 
 static void __put_nfs_open_context(struct nfs_open_context *ctx, int is_sync)
 {
     struct inode *inode = d_inode(ctx->dentry);
     struct super_block *sb = ctx->dentry->d_sb;
 
     if (!refcount_dec_and_test(&ctx->lock_context.count))
         return;
     if (!list_empty(&ctx->list)) {
         spin_lock(&inode->i_lock);
         list_del_rcu(&ctx->list);
         spin_unlock(&inode->i_lock);
     }
     if (inode != NULL)
         NFS_PROTO(inode)->close_context(ctx, is_sync);
     put_cred(ctx->cred);
     dput(ctx->dentry);
     nfs_sb_deactive(sb);
     put_rpccred(rcu_dereference_protected(ctx->ll_cred, 1));
     kfree(ctx->mdsthreshold);
     kfree_rcu(ctx, rcu_head);
 }
 
 void put_nfs_open_context(struct nfs_open_context *ctx)
 {
     __put_nfs_open_context(ctx, 0);
 }
 EXPORT_SYMBOL_GPL(put_nfs_open_context);
 
 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
  */
 void nfs_inode_attach_open_context(struct nfs_open_context *ctx)
 {
     struct inode *inode = d_inode(ctx->dentry);
     struct nfs_inode *nfsi = NFS_I(inode);
 
     spin_lock(&inode->i_lock);
     if (list_empty(&nfsi->open_files) &&
         (nfsi->cache_validity & NFS_INO_DATA_INVAL_DEFER))
         nfs_set_cache_invalid(inode, NFS_INO_INVALID_DATA |
                              NFS_INO_REVAL_FORCED);
     list_add_tail_rcu(&ctx->list, &nfsi->open_files);
     spin_unlock(&inode->i_lock);
 }
 EXPORT_SYMBOL_GPL(nfs_inode_attach_open_context);
 
 void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx)
 {
     filp->private_data = get_nfs_open_context(ctx);
     set_bit(NFS_CONTEXT_FILE_OPEN, &ctx->flags);
     if (list_empty(&ctx->list))
         nfs_inode_attach_open_context(ctx);
 }
 EXPORT_SYMBOL_GPL(nfs_file_set_open_context);
 
 /*
  * Given an inode, search for an open context with the desired characteristics
  */
 struct nfs_open_context *nfs_find_open_context(struct inode *inode, const struct cred *cred, fmode_t mode)
 {
     struct nfs_inode *nfsi = NFS_I(inode);
     struct nfs_open_context *pos, *ctx = NULL;
 
     rcu_read_lock();
     list_for_each_entry_rcu(pos, &nfsi->open_files, list) {
         if (cred != NULL && cred_fscmp(pos->cred, cred) != 0)
             continue;
         if ((pos->mode & (FMODE_READ|FMODE_WRITE)) != mode)
             continue;
         if (!test_bit(NFS_CONTEXT_FILE_OPEN, &pos->flags))
             continue;
         ctx = get_nfs_open_context(pos);
         if (ctx)
             break;
     }
     rcu_read_unlock();
     return ctx;
 }
 
 void nfs_file_clear_open_context(struct file *filp)
 {
     struct nfs_open_context *ctx = nfs_file_open_context(filp);
 
     if (ctx) {
         struct inode *inode = d_inode(ctx->dentry);
 
         clear_bit(NFS_CONTEXT_FILE_OPEN, &ctx->flags);
         /*
          * We fatal error on write before. Try to writeback
          * every page again.
          */
         if (ctx->error < 0)
             invalidate_inode_pages2(inode->i_mapping);
         filp->private_data = NULL;
         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;
 
     ctx = alloc_nfs_open_context(file_dentry(filp), filp->f_mode, filp);
     if (IS_ERR(ctx))
         return PTR_ERR(ctx);
     nfs_file_set_open_context(filp, ctx);
     put_nfs_open_context(ctx);
     nfs_fscache_open_file(inode, 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 = NULL;
     struct nfs_inode *nfsi = NFS_I(inode);
 
     dfprintk(PAGECACHE, "NFS: revalidating (%s/%Lu)\n",
         inode->i_sb->s_id, (unsigned long long)NFS_FILEID(inode));
 
     trace_nfs_revalidate_inode_enter(inode);
 
     if (is_bad_inode(inode))
         goto out;
     if (NFS_STALE(inode))
         goto out;
 
     /* pNFS: Attributes aren't updated until we layoutcommit */
     if (S_ISREG(inode->i_mode)) {
         status = pnfs_sync_inode(inode, false);
         if (status)
             goto out;
     }
 
     status = -ENOMEM;
     fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode));
     if (fattr == NULL)
         goto out;
 
     nfs_inc_stats(inode, NFSIOS_INODEREVALIDATE);
 
     status = NFS_PROTO(inode)->getattr(server, NFS_FH(inode), fattr, inode);
     if (status != 0) {
         dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Lu) getattr failed, error=%d\n",
              inode->i_sb->s_id,
              (unsigned long long)NFS_FILEID(inode), status);
         switch (status) {
         case -ETIMEDOUT:
             /* A soft timeout occurred. Use cached information? */
             if (server->flags & NFS_MOUNT_SOFTREVAL)
                 status = 0;
             break;
         case -ESTALE:
             if (!S_ISDIR(inode->i_mode))
                 nfs_set_inode_stale(inode);
             else
                 nfs_zap_caches(inode);
         }
         goto out;
     }
 
     status = nfs_refresh_inode(inode, fattr);
     if (status) {
         dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Lu) refresh failed, error=%d\n",
              inode->i_sb->s_id,
              (unsigned long long)NFS_FILEID(inode), status);
         goto out;
     }
 
     if (nfsi->cache_validity & NFS_INO_INVALID_ACL)
         nfs_zap_acl_cache(inode);
 
     nfs_setsecurity(inode, fattr);
 
     dfprintk(PAGECACHE, "NFS: (%s/%Lu) revalidation complete\n",
         inode->i_sb->s_id,
         (unsigned long long)NFS_FILEID(inode));
 
 out:
     nfs_free_fattr(fattr);
     trace_nfs_revalidate_inode_exit(inode, status);
     return status;
 }
 
 int nfs_attribute_cache_expired(struct inode *inode)
 {
     if (nfs_have_delegated_attributes(inode))
         return 0;
     return nfs_attribute_timeout(inode);
 }
 
 /**
  * nfs_revalidate_inode - Revalidate the inode attributes
  * @inode: pointer to inode struct
  * @flags: cache flags to check
  *
  * Updates inode attribute information by retrieving the data from the server.
  */
 int nfs_revalidate_inode(struct inode *inode, unsigned long flags)
 {
     if (!nfs_check_cache_invalid(inode, flags))
         return NFS_STALE(inode) ? -ESTALE : 0;
     return __nfs_revalidate_inode(NFS_SERVER(inode), inode);
 }
 EXPORT_SYMBOL_GPL(nfs_revalidate_inode);
 
 static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
 {
     int ret;
 
     nfs_fscache_invalidate(inode, 0);
     if (mapping->nrpages != 0) {
         if (S_ISREG(inode->i_mode)) {
             ret = nfs_sync_mapping(mapping);
             if (ret < 0)
                 return ret;
         }
         ret = invalidate_inode_pages2(mapping);
         if (ret < 0)
             return ret;
     }
     nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
 
     dfprintk(PAGECACHE, "NFS: (%s/%Lu) data cache invalidated\n",
             inode->i_sb->s_id,
             (unsigned long long)NFS_FILEID(inode));
     return 0;
 }
 
 /**
  * nfs_clear_invalid_mapping - Conditionally clear a mapping
  * @mapping: pointer to mapping
  *
  * If the NFS_INO_INVALID_DATA inode flag is set, clear the mapping.
  */
 int nfs_clear_invalid_mapping(struct address_space *mapping)
 {
     struct inode *inode = mapping->host;
     struct nfs_inode *nfsi = NFS_I(inode);
     unsigned long *bitlock = &nfsi->flags;
     int ret = 0;
 
     /*
      * We must clear NFS_INO_INVALID_DATA first to ensure that
      * invalidations that come in while we're shooting down the mappings
      * are respected. But, that leaves a race window where one revalidator
      * can clear the flag, and then another checks it before the mapping
      * gets invalidated. Fix that by serializing access to this part of
      * the function.
      *
      * At the same time, we need to allow other tasks to see whether we
      * might be in the middle of invalidating the pages, so we only set
      * the bit lock here if it looks like we're going to be doing that.
      */
     for (;;) {
         ret = wait_on_bit_action(bitlock, NFS_INO_INVALIDATING,
                      nfs_wait_bit_killable, TASK_KILLABLE);
         if (ret)
             goto out;
         spin_lock(&inode->i_lock);
         if (test_bit(NFS_INO_INVALIDATING, bitlock)) {
             spin_unlock(&inode->i_lock);
             continue;
         }
         if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
             break;
         spin_unlock(&inode->i_lock);
         goto out;
     }
 
     set_bit(NFS_INO_INVALIDATING, bitlock);
     smp_wmb();
     nfsi->cache_validity &=
         ~(NFS_INO_INVALID_DATA | NFS_INO_DATA_INVAL_DEFER);
     spin_unlock(&inode->i_lock);
     trace_nfs_invalidate_mapping_enter(inode);
     ret = nfs_invalidate_mapping(inode, mapping);
     trace_nfs_invalidate_mapping_exit(inode, ret);
 
     clear_bit_unlock(NFS_INO_INVALIDATING, bitlock);
     smp_mb__after_atomic();
     wake_up_bit(bitlock, NFS_INO_INVALIDATING);
 out:
     return ret;
 }
 
 bool nfs_mapping_need_revalidate_inode(struct inode *inode)
 {
     return nfs_check_cache_invalid(inode, NFS_INO_INVALID_CHANGE) ||
         NFS_STALE(inode);
 }
 
 int nfs_revalidate_mapping_rcu(struct inode *inode)
 {
     struct nfs_inode *nfsi = NFS_I(inode);
     unsigned long *bitlock = &nfsi->flags;
     int ret = 0;
 
     if (IS_SWAPFILE(inode))
         goto out;
     if (nfs_mapping_need_revalidate_inode(inode)) {
         ret = -ECHILD;
         goto out;
     }
     spin_lock(&inode->i_lock);
     if (test_bit(NFS_INO_INVALIDATING, bitlock) ||
         (nfsi->cache_validity & NFS_INO_INVALID_DATA))
         ret = -ECHILD;
     spin_unlock(&inode->i_lock);
 out:
     return ret;
 }
 
 /**
  * nfs_revalidate_mapping - Revalidate the pagecache
  * @inode: pointer to host inode
  * @mapping: pointer to mapping
  */
 int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
 {
     /* swapfiles are not supposed to be shared. */
     if (IS_SWAPFILE(inode))
         return 0;
 
     if (nfs_mapping_need_revalidate_inode(inode)) {
         int ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
         if (ret < 0)
             return ret;
     }
 
     return nfs_clear_invalid_mapping(mapping);
 }
 
 static bool nfs_file_has_writers(struct nfs_inode *nfsi)
 {
     struct inode *inode = &nfsi->vfs_inode;
 
     if (!S_ISREG(inode->i_mode))
         return false;
     if (list_empty(&nfsi->open_files))
         return false;
     return inode_is_open_for_write(inode);
 }
 
 static bool nfs_file_has_buffered_writers(struct nfs_inode *nfsi)
 {
     return nfs_file_has_writers(nfsi) && nfs_file_io_is_buffered(nfsi);
 }
 
 static void nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 {
     struct timespec64 ts;
 
     if ((fattr->valid & NFS_ATTR_FATTR_PRECHANGE)
             && (fattr->valid & NFS_ATTR_FATTR_CHANGE)
             && inode_eq_iversion_raw(inode, fattr->pre_change_attr)) {
         inode_set_iversion_raw(inode, fattr->change_attr);
         if (S_ISDIR(inode->i_mode))
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_DATA);
         else if (nfs_server_capable(inode, NFS_CAP_XATTR))
             nfs_set_cache_invalid(inode, NFS_INO_INVALID_XATTR);
     }
     /* If we have atomic WCC data, we may update some attributes */
     ts = inode->i_ctime;
     if ((fattr->valid & NFS_ATTR_FATTR_PRECTIME)
             && (fattr->valid & NFS_ATTR_FATTR_CTIME)
             && timespec64_equal(&ts, &fattr->pre_ctime)) {
         inode->i_ctime = fattr->ctime;
     }
 
     ts = inode->i_mtime;
     if ((fattr->valid & NFS_ATTR_FATTR_PREMTIME)
             && (fattr->valid & NFS_ATTR_FATTR_MTIME)
             && timespec64_equal(&ts, &fattr->pre_mtime)) {
         inode->i_mtime = fattr->mtime;
     }
     if ((fattr->valid & NFS_ATTR_FATTR_PRESIZE)
             && (fattr->valid & NFS_ATTR_FATTR_SIZE)
             && i_size_read(inode) == nfs_size_to_loff_t(fattr->pre_size)
             && !nfs_have_writebacks(inode)) {
         trace_nfs_size_wcc(inode, fattr->size);
         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;
     struct timespec64 ts;
 
     if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
         return 0;
 
     if (!(fattr->valid & NFS_ATTR_FATTR_FILEID)) {
         /* Only a mounted-on-fileid? Just exit */
         if (fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID)
             return 0;
     /* Has the inode gone and changed behind our back? */
     } else if (nfsi->fileid != fattr->fileid) {
         /* Is this perhaps the mounted-on fileid? */
         if ((fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID) &&
             nfsi->fileid == fattr->mounted_on_fileid)
             return 0;
         return -ESTALE;
     }
     if ((fattr->valid & NFS_ATTR_FATTR_TYPE) && inode_wrong_type(inode, fattr->mode))
         return -ESTALE;
 
 
     if (!nfs_file_has_buffered_writers(nfsi)) {
         /* Verify a few of the more important attributes */
         if ((fattr->valid & NFS_ATTR_FATTR_CHANGE) != 0 && !inode_eq_iversion_raw(inode, fattr->change_attr))
             invalid |= NFS_INO_INVALID_CHANGE;
 
         ts = inode->i_mtime;
         if ((fattr->valid & NFS_ATTR_FATTR_MTIME) && !timespec64_equal(&ts, &fattr->mtime))
             invalid |= NFS_INO_INVALID_MTIME;
 
         ts = inode->i_ctime;
         if ((fattr->valid & NFS_ATTR_FATTR_CTIME) && !timespec64_equal(&ts, &fattr->ctime))
             invalid |= NFS_INO_INVALID_CTIME;
 
         if (fattr->valid & NFS_ATTR_FATTR_SIZE) {
             cur_size = i_size_read(inode);
             new_isize = nfs_size_to_loff_t(fattr->size);
             if (cur_size != new_isize)
                 invalid |= NFS_INO_INVALID_SIZE;
         }
     }
 
     /* Have any file permissions changed? */
     if ((fattr->valid & NFS_ATTR_FATTR_MODE) && (inode->i_mode & S_IALLUGO) != (fattr->mode & S_IALLUGO))
         invalid |= NFS_INO_INVALID_MODE;
     if ((fattr->valid & NFS_ATTR_FATTR_OWNER) && !uid_eq(inode->i_uid, fattr->uid))
         invalid |= NFS_INO_INVALID_OTHER;
     if ((fattr->valid & NFS_ATTR_FATTR_GROUP) && !gid_eq(inode->i_gid, fattr->gid))
         invalid |= NFS_INO_INVALID_OTHER;
 
     /* Has the link count changed? */
     if ((fattr->valid & NFS_ATTR_FATTR_NLINK) && inode->i_nlink != fattr->nlink)
         invalid |= NFS_INO_INVALID_NLINK;
 
     ts = inode->i_atime;
     if ((fattr->valid & NFS_ATTR_FATTR_ATIME) && !timespec64_equal(&ts, &fattr->atime))
         invalid |= NFS_INO_INVALID_ATIME;
 
     if (invalid != 0)
         nfs_set_cache_invalid(inode, invalid);
 
     nfsi->read_cache_jiffies = fattr->time_start;
     return 0;
 }
 
 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);
 }
 EXPORT_SYMBOL_GPL(nfs_inc_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();
     fattr->owner_name = NULL;
     fattr->group_name = NULL;
 }
 EXPORT_SYMBOL_GPL(nfs_fattr_init);
 
 /**
  * nfs_fattr_set_barrier
  * @fattr: attributes
  *
  * Used to set a barrier after an attribute was updated. This
  * barrier ensures that older attributes from RPC calls that may
  * have raced with our update cannot clobber these new values.
  * Note that you are still responsible for ensuring that other
  * operations which change the attribute on the server do not
  * collide.
  */
 void nfs_fattr_set_barrier(struct nfs_fattr *fattr)
 {
     fattr->gencount = nfs_inc_attr_generation_counter();
 }
 
 struct nfs_fattr *nfs_alloc_fattr(void)
 {
     struct nfs_fattr *fattr;
 
     fattr = kmalloc(sizeof(*fattr), GFP_KERNEL);
     if (fattr != NULL) {
         nfs_fattr_init(fattr);
         fattr->label = NULL;
     }
     return fattr;
 }
 EXPORT_SYMBOL_GPL(nfs_alloc_fattr);
 
 struct nfs_fattr *nfs_alloc_fattr_with_label(struct nfs_server *server)
 {
     struct nfs_fattr *fattr = nfs_alloc_fattr();
 
     if (!fattr)
         return NULL;
 
     fattr->label = nfs4_label_alloc(server, GFP_KERNEL);
     if (IS_ERR(fattr->label)) {
         kfree(fattr);
         return NULL;
     }
 
     return fattr;
 }
 EXPORT_SYMBOL_GPL(nfs_alloc_fattr_with_label);
 
 struct nfs_fh *nfs_alloc_fhandle(void)
 {
     struct nfs_fh *fh;
 
     fh = kmalloc(sizeof(struct nfs_fh), GFP_KERNEL);
     if (fh != NULL)
         fh->size = 0;
     return fh;
 }
 EXPORT_SYMBOL_GPL(nfs_alloc_fhandle);
 
 #ifdef NFS_DEBUG
 /*
  * _nfs_display_fhandle_hash - calculate the crc32 hash for the filehandle
  *                             in the same way that wireshark does
  *
  * @fh: file handle
  *
  * For debugging only.
  */
 u32 _nfs_display_fhandle_hash(const struct nfs_fh *fh)
 {
     /* wireshark uses 32-bit AUTODIN crc and does a bitwise
      * not on the result */
     return nfs_fhandle_hash(fh);
 }
 EXPORT_SYMBOL_GPL(_nfs_display_fhandle_hash);
 
 /*
  * _nfs_display_fhandle - display an NFS file handle on the console
  *
  * @fh: file handle to display
  * @caption: display caption
  *
  * For debugging only.
  */
 void _nfs_display_fhandle(const struct nfs_fh *fh, const char *caption)
 {
     unsigned short i;
 
     if (fh == NULL || fh->size == 0) {
         printk(KERN_DEFAULT "%s at %p is empty\n", caption, fh);
         return;
     }
 
     printk(KERN_DEFAULT "%s at %p is %u bytes, crc: 0x%08x:\n",
            caption, fh, fh->size, _nfs_display_fhandle_hash(fh));
     for (i = 0; i < fh->size; i += 16) {
         __be32 *pos = (__be32 *)&fh->data[i];
 
         switch ((fh->size - i - 1) >> 2) {
         case 0:
             printk(KERN_DEFAULT " %08x\n",
                 be32_to_cpup(pos));
             break;
         case 1:
             printk(KERN_DEFAULT " %08x %08x\n",
                 be32_to_cpup(pos), be32_to_cpup(pos + 1));
             break;
         case 2:
             printk(KERN_DEFAULT " %08x %08x %08x\n",
                 be32_to_cpup(pos), be32_to_cpup(pos + 1),
                 be32_to_cpup(pos + 2));
             break;
         default:
             printk(KERN_DEFAULT " %08x %08x %08x %08x\n",
                 be32_to_cpup(pos), be32_to_cpup(pos + 1),
                 be32_to_cpup(pos + 2), be32_to_cpup(pos + 3));
         }
     }
 }
 EXPORT_SYMBOL_GPL(_nfs_display_fhandle);
 #endif
 
 /**
  * nfs_inode_attrs_cmp_generic - compare attributes
  * @fattr: attributes
  * @inode: pointer to inode
  *
  * Attempt to divine whether or not an RPC call reply carrying stale
  * attributes got scheduled after another call carrying updated ones.
  * Note also the check for wraparound of 'attr_gencount'
  *
  * The function returns '1' if it thinks the attributes in @fattr are
  * more recent than the ones cached in @inode. Otherwise it returns
  * the value '0'.
  */
 static int nfs_inode_attrs_cmp_generic(const struct nfs_fattr *fattr,
                        const struct inode *inode)
 {
     unsigned long attr_gencount = NFS_I(inode)->attr_gencount;
 
     return (long)(fattr->gencount - attr_gencount) > 0 ||
            (long)(attr_gencount - nfs_read_attr_generation_counter()) > 0;
 }
 
 /**
  * nfs_inode_attrs_cmp_monotonic - compare attributes
  * @fattr: attributes
  * @inode: pointer to inode
  *
  * Attempt to divine whether or not an RPC call reply carrying stale
  * attributes got scheduled after another call carrying updated ones.
  *
  * We assume that the server observes monotonic semantics for
  * the change attribute, so a larger value means that the attributes in
  * @fattr are more recent, in which case the function returns the
  * value '1'.
  * A return value of '0' indicates no measurable change
  * A return value of '-1' means that the attributes in @inode are
  * more recent.
  */
 static int nfs_inode_attrs_cmp_monotonic(const struct nfs_fattr *fattr,
                      const struct inode *inode)
 {
     s64 diff = fattr->change_attr - inode_peek_iversion_raw(inode);
     if (diff > 0)
         return 1;
     return diff == 0 ? 0 : -1;
 }
 
 /**
  * nfs_inode_attrs_cmp_strict_monotonic - compare attributes
  * @fattr: attributes
  * @inode: pointer to inode
  *
  * Attempt to divine whether or not an RPC call reply carrying stale
  * attributes got scheduled after another call carrying updated ones.
  *
  * We assume that the server observes strictly monotonic semantics for
  * the change attribute, so a larger value means that the attributes in
  * @fattr are more recent, in which case the function returns the
  * value '1'.
  * A return value of '-1' means that the attributes in @inode are
  * more recent or unchanged.
  */
 static int nfs_inode_attrs_cmp_strict_monotonic(const struct nfs_fattr *fattr,
                         const struct inode *inode)
 {
     return  nfs_inode_attrs_cmp_monotonic(fattr, inode) > 0 ? 1 : -1;
 }
 
 /**
  * nfs_inode_attrs_cmp - compare attributes
  * @fattr: attributes
  * @inode: pointer to inode
  *
  * This function returns '1' if it thinks the attributes in @fattr are
  * more recent than the ones cached in @inode. It returns '-1' if
  * the attributes in @inode are more recent than the ones in @fattr,
  * and it returns 0 if not sure.
  */
 static int nfs_inode_attrs_cmp(const struct nfs_fattr *fattr,
                    const struct inode *inode)
 {
     if (nfs_inode_attrs_cmp_generic(fattr, inode) > 0)
         return 1;
     switch (NFS_SERVER(inode)->change_attr_type) {
     case NFS4_CHANGE_TYPE_IS_UNDEFINED:
         break;
     case NFS4_CHANGE_TYPE_IS_TIME_METADATA:
         if (!(fattr->valid & NFS_ATTR_FATTR_CHANGE))
             break;
         return nfs_inode_attrs_cmp_monotonic(fattr, inode);
     default:
         if (!(fattr->valid & NFS_ATTR_FATTR_CHANGE))
             break;
         return nfs_inode_attrs_cmp_strict_monotonic(fattr, inode);
     }
     return 0;
 }
 
 /**
  * nfs_inode_finish_partial_attr_update - complete a previous inode update
  * @fattr: attributes
  * @inode: pointer to inode
  *
  * Returns '1' if the last attribute update left the inode cached
  * attributes in a partially unrevalidated state, and @fattr
  * matches the change attribute of that partial update.
  * Otherwise returns '0'.
  */
 static int nfs_inode_finish_partial_attr_update(const struct nfs_fattr *fattr,
                         const struct inode *inode)
 {
     const unsigned long check_valid =
         NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
         NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
         NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_OTHER |
         NFS_INO_INVALID_NLINK;
     unsigned long cache_validity = NFS_I(inode)->cache_validity;
     enum nfs4_change_attr_type ctype = NFS_SERVER(inode)->change_attr_type;
 
     if (ctype != NFS4_CHANGE_TYPE_IS_UNDEFINED &&
         !(cache_validity & NFS_INO_INVALID_CHANGE) &&
         (cache_validity & check_valid) != 0 &&
         (fattr->valid & NFS_ATTR_FATTR_CHANGE) != 0 &&
         nfs_inode_attrs_cmp_monotonic(fattr, inode) == 0)
         return 1;
     return 0;
 }
 
 static int nfs_refresh_inode_locked(struct inode *inode,
                     struct nfs_fattr *fattr)
 {
     int attr_cmp = nfs_inode_attrs_cmp(fattr, inode);
     int ret = 0;
 
     trace_nfs_refresh_inode_enter(inode);
 
     if (attr_cmp > 0 || nfs_inode_finish_partial_attr_update(fattr, inode))
         ret = nfs_update_inode(inode, fattr);
     else if (attr_cmp == 0)
         ret = nfs_check_inode_attributes(inode, fattr);
 
     trace_nfs_refresh_inode_exit(inode, ret);
     return ret;
 }
 
 /**
  * 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;
 }
 EXPORT_SYMBOL_GPL(nfs_refresh_inode);
 
 static int nfs_post_op_update_inode_locked(struct inode *inode,
         struct nfs_fattr *fattr, unsigned int invalid)
 {
     if (S_ISDIR(inode->i_mode))
         invalid |= NFS_INO_INVALID_DATA;
     nfs_set_cache_invalid(inode, invalid);
     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);
     nfs_fattr_set_barrier(fattr);
     status = nfs_post_op_update_inode_locked(inode, fattr,
             NFS_INO_INVALID_CHANGE
             | NFS_INO_INVALID_CTIME
             | NFS_INO_REVAL_FORCED);
     spin_unlock(&inode->i_lock);
 
     return status;
 }
 EXPORT_SYMBOL_GPL(nfs_post_op_update_inode);
 
 /**
  * nfs_post_op_update_inode_force_wcc_locked - 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_locked(struct inode *inode, struct nfs_fattr *fattr)
 {
     int attr_cmp = nfs_inode_attrs_cmp(fattr, inode);
     int status;
 
     /* Don't do a WCC update if these attributes are already stale */
     if (attr_cmp < 0)
         return 0;
     if ((fattr->valid & NFS_ATTR_FATTR) == 0 || !attr_cmp) {
         fattr->valid &= ~(NFS_ATTR_FATTR_PRECHANGE
                 | NFS_ATTR_FATTR_PRESIZE
                 | NFS_ATTR_FATTR_PREMTIME
                 | NFS_ATTR_FATTR_PRECTIME);
         goto out_noforce;
     }
     if ((fattr->valid & NFS_ATTR_FATTR_CHANGE) != 0 &&
             (fattr->valid & NFS_ATTR_FATTR_PRECHANGE) == 0) {
         fattr->pre_change_attr = inode_peek_iversion_raw(inode);
         fattr->valid |= NFS_ATTR_FATTR_PRECHANGE;
     }
     if ((fattr->valid & NFS_ATTR_FATTR_CTIME) != 0 &&
             (fattr->valid & NFS_ATTR_FATTR_PRECTIME) == 0) {
         fattr->pre_ctime = inode->i_ctime;
         fattr->valid |= NFS_ATTR_FATTR_PRECTIME;
     }
     if ((fattr->valid & NFS_ATTR_FATTR_MTIME) != 0 &&
             (fattr->valid & NFS_ATTR_FATTR_PREMTIME) == 0) {
         fattr->pre_mtime = inode->i_mtime;
         fattr->valid |= NFS_ATTR_FATTR_PREMTIME;
     }
     if ((fattr->valid & NFS_ATTR_FATTR_SIZE) != 0 &&
             (fattr->valid & NFS_ATTR_FATTR_PRESIZE) == 0) {
         fattr->pre_size = i_size_read(inode);
         fattr->valid |= NFS_ATTR_FATTR_PRESIZE;
     }
 out_noforce:
     status = nfs_post_op_update_inode_locked(inode, fattr,
             NFS_INO_INVALID_CHANGE
             | NFS_INO_INVALID_CTIME
             | NFS_INO_INVALID_MTIME
             | NFS_INO_INVALID_BLOCKS);
     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);
     nfs_fattr_set_barrier(fattr);
     status = nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
     spin_unlock(&inode->i_lock);
     return status;
 }
 EXPORT_SYMBOL_GPL(nfs_post_op_update_inode_force_wcc);
 
 
 /*
  * 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 = NFS_SERVER(inode);
     struct nfs_inode *nfsi = NFS_I(inode);
     loff_t cur_isize, new_isize;
     u64 fattr_supported = server->fattr_valid;
     unsigned long invalid = 0;
     unsigned long now = jiffies;
     unsigned long save_cache_validity;
     bool have_writers = nfs_file_has_buffered_writers(nfsi);
     bool cache_revalidated = true;
     bool attr_changed = false;
     bool have_delegation;
 
     dfprintk(VFS, "NFS: %s(%s/%lu fh_crc=0x%08x ct=%d info=0x%x)\n",
             __func__, inode->i_sb->s_id, inode->i_ino,
             nfs_display_fhandle_hash(NFS_FH(inode)),
             atomic_read(&inode->i_count), fattr->valid);
 
     if (!(fattr->valid & NFS_ATTR_FATTR_FILEID)) {
         /* Only a mounted-on-fileid? Just exit */
         if (fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID)
             return 0;
     /* Has the inode gone and changed behind our back? */
     } else if (nfsi->fileid != fattr->fileid) {
         /* Is this perhaps the mounted-on fileid? */
         if ((fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID) &&
             nfsi->fileid == fattr->mounted_on_fileid)
             return 0;
         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;
     }
 
     /*
      * Make sure the inode's type hasn't changed.
      */
     if ((fattr->valid & NFS_ATTR_FATTR_TYPE) && inode_wrong_type(inode, fattr->mode)) {
         /*
         * Big trouble! The inode has become a different object.
         */
         printk(KERN_DEBUG "NFS: %s: inode %lu mode changed, %07o to %07o\n",
                 __func__, inode->i_ino, inode->i_mode, fattr->mode);
         goto out_err;
     }
 
     /* Update the fsid? */
     if (S_ISDIR(inode->i_mode) && (fattr->valid & NFS_ATTR_FATTR_FSID) &&
             !nfs_fsid_equal(&server->fsid, &fattr->fsid) &&
             !IS_AUTOMOUNT(inode))
         server->fsid = fattr->fsid;
 
     /* Save the delegation state before clearing cache_validity */
     have_delegation = nfs_have_delegated_attributes(inode);
 
     /*
      * Update the read time so we don't revalidate too often.
      */
     nfsi->read_cache_jiffies = fattr->time_start;
 
     save_cache_validity = nfsi->cache_validity;
     nfsi->cache_validity &= ~(NFS_INO_INVALID_ATTR
             | NFS_INO_INVALID_ATIME
             | NFS_INO_REVAL_FORCED
             | NFS_INO_INVALID_BLOCKS);
 
     /* Do atomic weak cache consistency updates */
     nfs_wcc_update_inode(inode, fattr);
 
     if (pnfs_layoutcommit_outstanding(inode)) {
         nfsi->cache_validity |=
             save_cache_validity &
             (NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_CTIME |
              NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
              NFS_INO_INVALID_BLOCKS);
         cache_revalidated = false;
     }
 
     /* More cache consistency checks */
     if (fattr->valid & NFS_ATTR_FATTR_CHANGE) {
         if (!inode_eq_iversion_raw(inode, fattr->change_attr)) {
             /* Could it be a race with writeback? */
             if (!(have_writers || have_delegation)) {
                 invalid |= NFS_INO_INVALID_DATA
                     | NFS_INO_INVALID_ACCESS
                     | NFS_INO_INVALID_ACL
                     | NFS_INO_INVALID_XATTR;
                 /* Force revalidate of all attributes */
                 save_cache_validity |= NFS_INO_INVALID_CTIME
                     | NFS_INO_INVALID_MTIME
                     | NFS_INO_INVALID_SIZE
                     | NFS_INO_INVALID_BLOCKS
                     | NFS_INO_INVALID_NLINK
                     | NFS_INO_INVALID_MODE
                     | NFS_INO_INVALID_OTHER;
                 if (S_ISDIR(inode->i_mode))
                     nfs_force_lookup_revalidate(inode);
                 attr_changed = true;
                 dprintk("NFS: change_attr change on server for file %s/%ld\n",
                         inode->i_sb->s_id,
                         inode->i_ino);
             } else if (!have_delegation)
                 nfsi->cache_validity |= NFS_INO_DATA_INVAL_DEFER;
             inode_set_iversion_raw(inode, fattr->change_attr);
         }
     } else {
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_CHANGE;
         if (!have_delegation ||
             (nfsi->cache_validity & NFS_INO_INVALID_CHANGE) != 0)
             cache_revalidated = false;
     }
 
     if (fattr->valid & NFS_ATTR_FATTR_MTIME)
         inode->i_mtime = fattr->mtime;
     else if (fattr_supported & NFS_ATTR_FATTR_MTIME)
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_MTIME;
 
     if (fattr->valid & NFS_ATTR_FATTR_CTIME)
         inode->i_ctime = fattr->ctime;
     else if (fattr_supported & NFS_ATTR_FATTR_CTIME)
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_CTIME;
 
     /* Check if our cached file size is stale */
     if (fattr->valid & NFS_ATTR_FATTR_SIZE) {
         new_isize = nfs_size_to_loff_t(fattr->size);
         cur_isize = i_size_read(inode);
         if (new_isize != cur_isize && !have_delegation) {
             /* Do we perhaps have any outstanding writes, or has
              * the file grown beyond our last write? */
             if (!nfs_have_writebacks(inode) || new_isize > cur_isize) {
                 trace_nfs_size_update(inode, new_isize);
                 i_size_write(inode, new_isize);
                 if (!have_writers)
                     invalid |= NFS_INO_INVALID_DATA;
             }
         }
         if (new_isize == 0 &&
             !(fattr->valid & (NFS_ATTR_FATTR_SPACE_USED |
                       NFS_ATTR_FATTR_BLOCKS_USED))) {
             fattr->du.nfs3.used = 0;
             fattr->valid |= NFS_ATTR_FATTR_SPACE_USED;
         }
     } else
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_SIZE;
 
     if (fattr->valid & NFS_ATTR_FATTR_ATIME)
         inode->i_atime = fattr->atime;
     else if (fattr_supported & NFS_ATTR_FATTR_ATIME)
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_ATIME;
 
     if (fattr->valid & NFS_ATTR_FATTR_MODE) {
         if ((inode->i_mode & S_IALLUGO) != (fattr->mode & S_IALLUGO)) {
             umode_t newmode = inode->i_mode & S_IFMT;
             newmode |= fattr->mode & S_IALLUGO;
             inode->i_mode = newmode;
             invalid |= NFS_INO_INVALID_ACCESS
                 | NFS_INO_INVALID_ACL;
         }
     } else if (fattr_supported & NFS_ATTR_FATTR_MODE)
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_MODE;
 
     if (fattr->valid & NFS_ATTR_FATTR_OWNER) {
         if (!uid_eq(inode->i_uid, fattr->uid)) {
             invalid |= NFS_INO_INVALID_ACCESS
                 | NFS_INO_INVALID_ACL;
             inode->i_uid = fattr->uid;
         }
     } else if (fattr_supported & NFS_ATTR_FATTR_OWNER)
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_OTHER;
 
     if (fattr->valid & NFS_ATTR_FATTR_GROUP) {
         if (!gid_eq(inode->i_gid, fattr->gid)) {
             invalid |= NFS_INO_INVALID_ACCESS
                 | NFS_INO_INVALID_ACL;
             inode->i_gid = fattr->gid;
         }
     } else if (fattr_supported & NFS_ATTR_FATTR_GROUP)
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_OTHER;
 
     if (fattr->valid & NFS_ATTR_FATTR_NLINK) {
         if (inode->i_nlink != fattr->nlink)
             set_nlink(inode, fattr->nlink);
     } else if (fattr_supported & NFS_ATTR_FATTR_NLINK)
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_NLINK;
 
     if (fattr->valid & NFS_ATTR_FATTR_SPACE_USED) {
         /*
          * report the blocks in 512byte units
          */
         inode->i_blocks = nfs_calc_block_size(fattr->du.nfs3.used);
     } else if (fattr_supported & NFS_ATTR_FATTR_SPACE_USED)
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_BLOCKS;
 
     if (fattr->valid & NFS_ATTR_FATTR_BLOCKS_USED)
         inode->i_blocks = fattr->du.nfs2.blocks;
     else if (fattr_supported & NFS_ATTR_FATTR_BLOCKS_USED)
         nfsi->cache_validity |=
             save_cache_validity & NFS_INO_INVALID_BLOCKS;
 
     /* Update attrtimeo value if we're out of the unstable period */
     if (attr_changed) {
         nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);
         nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
         nfsi->attrtimeo_timestamp = now;
         /* Set barrier to be more recent than all outstanding updates */
         nfsi->attr_gencount = nfs_inc_attr_generation_counter();
     } else {
         if (cache_revalidated) {
             if (!time_in_range_open(now, nfsi->attrtimeo_timestamp,
                 nfsi->attrtimeo_timestamp + nfsi->attrtimeo)) {
                 nfsi->attrtimeo <<= 1;
                 if (nfsi->attrtimeo > NFS_MAXATTRTIMEO(inode))
                     nfsi->attrtimeo = NFS_MAXATTRTIMEO(inode);
             }
             nfsi->attrtimeo_timestamp = now;
         }
         /* Set the barrier to be more recent than this fattr */
         if ((long)(fattr->gencount - nfsi->attr_gencount) > 0)
             nfsi->attr_gencount = fattr->gencount;
     }
 
     /* 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;
     nfs_set_cache_invalid(inode, invalid);
 
     return 0;
  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_set_inode_stale_locked(inode);
     return -ESTALE;
 }
 
 struct inode *nfs_alloc_inode(struct super_block *sb)
 {
     struct nfs_inode *nfsi;
     nfsi = alloc_inode_sb(sb, nfs_inode_cachep, GFP_KERNEL);
     if (!nfsi)
         return NULL;
     nfsi->flags = 0UL;
     nfsi->cache_validity = 0UL;
 #if IS_ENABLED(CONFIG_NFS_V4)
     nfsi->nfs4_acl = NULL;
 #endif /* CONFIG_NFS_V4 */
 #ifdef CONFIG_NFS_V4_2
     nfsi->xattr_cache = NULL;
 #endif
     return &nfsi->vfs_inode;
 }
 EXPORT_SYMBOL_GPL(nfs_alloc_inode);
 
 void nfs_free_inode(struct inode *inode)
 {
     kmem_cache_free(nfs_inode_cachep, NFS_I(inode));
 }
 EXPORT_SYMBOL_GPL(nfs_free_inode);
 
 static inline void nfs4_init_once(struct nfs_inode *nfsi)
 {
 #if IS_ENABLED(CONFIG_NFS_V4)
     INIT_LIST_HEAD(&nfsi->open_states);
     nfsi->delegation = NULL;
     init_rwsem(&nfsi->rwsem);
     nfsi->layout = NULL;
 #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);
     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|SLAB_ACCOUNT),
                          init_once);
     if (nfs_inode_cachep == NULL)
         return -ENOMEM;
 
     return 0;
 }
 
 static void nfs_destroy_inodecache(void)
 {
     /*
      * Make sure all delayed rcu free inodes are flushed before we
      * destroy cache.
      */
     rcu_barrier();
     kmem_cache_destroy(nfs_inode_cachep);
 }
 
 struct workqueue_struct *nfsiod_workqueue;
 EXPORT_SYMBOL_GPL(nfsiod_workqueue);
 
 /*
  * start up the nfsiod workqueue
  */
 static int nfsiod_start(void)
 {
     struct workqueue_struct *wq;
     dprintk("RPC:       creating workqueue nfsiod\n");
     wq = alloc_workqueue("nfsiod", WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
     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);
 }
 
 unsigned int nfs_net_id;
 EXPORT_SYMBOL_GPL(nfs_net_id);
 
 static int nfs_net_init(struct net *net)
 {
     nfs_clients_init(net);
     return nfs_fs_proc_net_init(net);
 }
 
 static void nfs_net_exit(struct net *net)
 {
     nfs_fs_proc_net_exit(net);
     nfs_clients_exit(net);
 }
 
 static struct pernet_operations nfs_net_ops = {
     .init = nfs_net_init,
     .exit = nfs_net_exit,
     .id   = &nfs_net_id,
     .size = sizeof(struct nfs_net),
 };
 
 /*
  * Initialize NFS
  */
 static int __init init_nfs_fs(void)
 {
     int err;
 
     err = nfs_sysfs_init();
     if (err < 0)
         goto out10;
 
     err = register_pernet_subsys(&nfs_net_ops);
     if (err < 0)
         goto out9;
 
     err = nfsiod_start();
     if (err)
         goto out7;
 
     err = nfs_fs_proc_init();
     if (err)
         goto out6;
 
     err = nfs_init_nfspagecache();
     if (err)
         goto out5;
 
     err = nfs_init_inodecache();
     if (err)
         goto out4;
 
     err = nfs_init_readpagecache();
     if (err)
         goto out3;
 
     err = nfs_init_writepagecache();
     if (err)
         goto out2;
 
     err = nfs_init_directcache();
     if (err)
         goto out1;
 
     rpc_proc_register(&init_net, &nfs_rpcstat);
 
     err = register_nfs_fs();
     if (err)
         goto out0;
 
     return 0;
 out0:
     rpc_proc_unregister(&init_net, "nfs");
     nfs_destroy_directcache();
 out1:
     nfs_destroy_writepagecache();
 out2:
     nfs_destroy_readpagecache();
 out3:
     nfs_destroy_inodecache();
 out4:
     nfs_destroy_nfspagecache();
 out5:
     nfs_fs_proc_exit();
 out6:
     nfsiod_stop();
 out7:
     unregister_pernet_subsys(&nfs_net_ops);
 out9:
     nfs_sysfs_exit();
 out10:
     return err;
 }
 
 static void __exit exit_nfs_fs(void)
 {
     nfs_destroy_directcache();
     nfs_destroy_writepagecache();
     nfs_destroy_readpagecache();
     nfs_destroy_inodecache();
     nfs_destroy_nfspagecache();
     unregister_pernet_subsys(&nfs_net_ops);
     rpc_proc_unregister(&init_net, "nfs");
     unregister_nfs_fs();
     nfs_fs_proc_exit();
     nfsiod_stop();
     nfs_sysfs_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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