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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

 /*
  *  pNFS functions to call and manage layout drivers.
  *
  *  Copyright (c) 2002 [year of first publication]
  *  The Regents of the University of Michigan
  *  All Rights Reserved
  *
  *  Dean Hildebrand <dhildebz@umich.edu>
  *
  *  Permission is granted to use, copy, create derivative works, and
  *  redistribute this software and such derivative works for any purpose,
  *  so long as the name of the University of Michigan is not used in
  *  any advertising or publicity pertaining to the use or distribution
  *  of this software without specific, written prior authorization. If
  *  the above copyright notice or any other identification of the
  *  University of Michigan is included in any copy of any portion of
  *  this software, then the disclaimer below must also be included.
  *
  *  This software is provided as is, without representation or warranty
  *  of any kind either express or implied, including without limitation
  *  the implied warranties of merchantability, fitness for a particular
  *  purpose, or noninfringement.  The Regents of the University of
  *  Michigan shall not be liable for any damages, including special,
  *  indirect, incidental, or consequential damages, with respect to any
  *  claim arising out of or in connection with the use of the software,
  *  even if it has been or is hereafter advised of the possibility of
  *  such damages.
  */
 
 #include <linux/nfs_fs.h>
 #include <linux/nfs_page.h>
 #include <linux/module.h>
 #include <linux/sort.h>
 #include "internal.h"
 #include "pnfs.h"
 #include "iostat.h"
 #include "nfs4trace.h"
 #include "delegation.h"
 #include "nfs42.h"
 #include "nfs4_fs.h"
 
 #define NFSDBG_FACILITY     NFSDBG_PNFS
 #define PNFS_LAYOUTGET_RETRY_TIMEOUT (120*HZ)
 
 /* Locking:
  *
  * pnfs_spinlock:
  *      protects pnfs_modules_tbl.
  */
 static DEFINE_SPINLOCK(pnfs_spinlock);
 
 /*
  * pnfs_modules_tbl holds all pnfs modules
  */
 static LIST_HEAD(pnfs_modules_tbl);
 
 static void pnfs_layoutreturn_before_put_layout_hdr(struct pnfs_layout_hdr *lo);
 static void pnfs_free_returned_lsegs(struct pnfs_layout_hdr *lo,
         struct list_head *free_me,
         const struct pnfs_layout_range *range,
         u32 seq);
 static bool pnfs_lseg_dec_and_remove_zero(struct pnfs_layout_segment *lseg,
                         struct list_head *tmp_list);
 
 /* Return the registered pnfs layout driver module matching given id */
 static struct pnfs_layoutdriver_type *
 find_pnfs_driver_locked(u32 id)
 {
     struct pnfs_layoutdriver_type *local;
 
     list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid)
         if (local->id == id)
             goto out;
     local = NULL;
 out:
     dprintk("%s: Searching for id %u, found %p\n", __func__, id, local);
     return local;
 }
 
 static struct pnfs_layoutdriver_type *
 find_pnfs_driver(u32 id)
 {
     struct pnfs_layoutdriver_type *local;
 
     spin_lock(&pnfs_spinlock);
     local = find_pnfs_driver_locked(id);
     if (local != NULL && !try_module_get(local->owner)) {
         dprintk("%s: Could not grab reference on module\n", __func__);
         local = NULL;
     }
     spin_unlock(&pnfs_spinlock);
     return local;
 }
 
 const struct pnfs_layoutdriver_type *pnfs_find_layoutdriver(u32 id)
 {
     return find_pnfs_driver(id);
 }
 
 void pnfs_put_layoutdriver(const struct pnfs_layoutdriver_type *ld)
 {
     if (ld)
         module_put(ld->owner);
 }
 
 void
 unset_pnfs_layoutdriver(struct nfs_server *nfss)
 {
     if (nfss->pnfs_curr_ld) {
         if (nfss->pnfs_curr_ld->clear_layoutdriver)
             nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
         /* Decrement the MDS count. Purge the deviceid cache if zero */
         if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count))
             nfs4_deviceid_purge_client(nfss->nfs_client);
         module_put(nfss->pnfs_curr_ld->owner);
     }
     nfss->pnfs_curr_ld = NULL;
 }
 
 /*
  * When the server sends a list of layout types, we choose one in the order
  * given in the list below.
  *
  * FIXME: should this list be configurable in some fashion? module param?
  *    mount option? something else?
  */
 static const u32 ld_prefs[] = {
     LAYOUT_SCSI,
     LAYOUT_BLOCK_VOLUME,
     LAYOUT_OSD2_OBJECTS,
     LAYOUT_FLEX_FILES,
     LAYOUT_NFSV4_1_FILES,
     0
 };
 
 static int
 ld_cmp(const void *e1, const void *e2)
 {
     u32 ld1 = *((u32 *)e1);
     u32 ld2 = *((u32 *)e2);
     int i;
 
     for (i = 0; ld_prefs[i] != 0; i++) {
         if (ld1 == ld_prefs[i])
             return -1;
 
         if (ld2 == ld_prefs[i])
             return 1;
     }
     return 0;
 }
 
 /*
  * Try to set the server's pnfs module to the pnfs layout type specified by id.
  * Currently only one pNFS layout driver per filesystem is supported.
  *
  * @ids array of layout types supported by MDS.
  */
 void
 set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
               struct nfs_fsinfo *fsinfo)
 {
     struct pnfs_layoutdriver_type *ld_type = NULL;
     u32 id;
     int i;
 
     if (fsinfo->nlayouttypes == 0)
         goto out_no_driver;
     if (!(server->nfs_client->cl_exchange_flags &
          (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) {
         printk(KERN_ERR "NFS: %s: cl_exchange_flags 0x%x\n",
             __func__, server->nfs_client->cl_exchange_flags);
         goto out_no_driver;
     }
 
     sort(fsinfo->layouttype, fsinfo->nlayouttypes,
         sizeof(*fsinfo->layouttype), ld_cmp, NULL);
 
     for (i = 0; i < fsinfo->nlayouttypes; i++) {
         id = fsinfo->layouttype[i];
         ld_type = find_pnfs_driver(id);
         if (!ld_type) {
             request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX,
                     id);
             ld_type = find_pnfs_driver(id);
         }
         if (ld_type)
             break;
     }
 
     if (!ld_type) {
         dprintk("%s: No pNFS module found!\n", __func__);
         goto out_no_driver;
     }
 
     server->pnfs_curr_ld = ld_type;
     if (ld_type->set_layoutdriver
         && ld_type->set_layoutdriver(server, mntfh)) {
         printk(KERN_ERR "NFS: %s: Error initializing pNFS layout "
             "driver %u.\n", __func__, id);
         module_put(ld_type->owner);
         goto out_no_driver;
     }
     /* Bump the MDS count */
     atomic_inc(&server->nfs_client->cl_mds_count);
 
     dprintk("%s: pNFS module for %u set\n", __func__, id);
     return;
 
 out_no_driver:
     dprintk("%s: Using NFSv4 I/O\n", __func__);
     server->pnfs_curr_ld = NULL;
 }
 
 int
 pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
 {
     int status = -EINVAL;
     struct pnfs_layoutdriver_type *tmp;
 
     if (ld_type->id == 0) {
         printk(KERN_ERR "NFS: %s id 0 is reserved\n", __func__);
         return status;
     }
     if (!ld_type->alloc_lseg || !ld_type->free_lseg) {
         printk(KERN_ERR "NFS: %s Layout driver must provide "
                "alloc_lseg and free_lseg.\n", __func__);
         return status;
     }
 
     spin_lock(&pnfs_spinlock);
     tmp = find_pnfs_driver_locked(ld_type->id);
     if (!tmp) {
         list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl);
         status = 0;
         dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id,
             ld_type->name);
     } else {
         printk(KERN_ERR "NFS: %s Module with id %d already loaded!\n",
             __func__, ld_type->id);
     }
     spin_unlock(&pnfs_spinlock);
 
     return status;
 }
 EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver);
 
 void
 pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
 {
     dprintk("%s Deregistering id:%u\n", __func__, ld_type->id);
     spin_lock(&pnfs_spinlock);
     list_del(&ld_type->pnfs_tblid);
     spin_unlock(&pnfs_spinlock);
 }
 EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
 
 /*
  * pNFS client layout cache
  */
 
 /* Need to hold i_lock if caller does not already hold reference */
 void
 pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo)
 {
     refcount_inc(&lo->plh_refcount);
 }
 
 static struct pnfs_layout_hdr *
 pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
 {
     struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
     return ld->alloc_layout_hdr(ino, gfp_flags);
 }
 
 static void
 pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
 {
     struct nfs_server *server = NFS_SERVER(lo->plh_inode);
     struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
 
     if (test_and_clear_bit(NFS_LAYOUT_HASHED, &lo->plh_flags)) {
         struct nfs_client *clp = server->nfs_client;
 
         spin_lock(&clp->cl_lock);
         list_del_rcu(&lo->plh_layouts);
         spin_unlock(&clp->cl_lock);
     }
     put_cred(lo->plh_lc_cred);
     return ld->free_layout_hdr(lo);
 }
 
 static void
 pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
 {
     struct nfs_inode *nfsi = NFS_I(lo->plh_inode);
     dprintk("%s: freeing layout cache %p\n", __func__, lo);
     nfsi->layout = NULL;
     /* Reset MDS Threshold I/O counters */
     nfsi->write_io = 0;
     nfsi->read_io = 0;
 }
 
 void
 pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
 {
     struct inode *inode;
     unsigned long i_state;
 
     if (!lo)
         return;
     inode = lo->plh_inode;
     pnfs_layoutreturn_before_put_layout_hdr(lo);
 
     if (refcount_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
         if (!list_empty(&lo->plh_segs))
             WARN_ONCE(1, "NFS: BUG unfreed layout segments.\n");
         pnfs_detach_layout_hdr(lo);
         i_state = inode->i_state;
         spin_unlock(&inode->i_lock);
         pnfs_free_layout_hdr(lo);
         /* Notify pnfs_destroy_layout_final() that we're done */
         if (i_state & (I_FREEING | I_CLEAR))
             wake_up_var(lo);
     }
 }
 
 static struct inode *
 pnfs_grab_inode_layout_hdr(struct pnfs_layout_hdr *lo)
 {
     struct inode *inode = igrab(lo->plh_inode);
     if (inode)
         return inode;
     set_bit(NFS_LAYOUT_INODE_FREEING, &lo->plh_flags);
     return NULL;
 }
 
 /*
  * Compare 2 layout stateid sequence ids, to see which is newer,
  * taking into account wraparound issues.
  */
 static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
 {
     return (s32)(s1 - s2) > 0;
 }
 
 static void pnfs_barrier_update(struct pnfs_layout_hdr *lo, u32 newseq)
 {
     if (pnfs_seqid_is_newer(newseq, lo->plh_barrier) || !lo->plh_barrier)
         lo->plh_barrier = newseq;
 }
 
 static void
 pnfs_set_plh_return_info(struct pnfs_layout_hdr *lo, enum pnfs_iomode iomode,
              u32 seq)
 {
     if (lo->plh_return_iomode != 0 && lo->plh_return_iomode != iomode)
         iomode = IOMODE_ANY;
     lo->plh_return_iomode = iomode;
     set_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags);
     /*
      * We must set lo->plh_return_seq to avoid livelocks with
      * pnfs_layout_need_return()
      */
     if (seq == 0)
         seq = be32_to_cpu(lo->plh_stateid.seqid);
     if (!lo->plh_return_seq || pnfs_seqid_is_newer(seq, lo->plh_return_seq))
         lo->plh_return_seq = seq;
     pnfs_barrier_update(lo, seq);
 }
 
 static void
 pnfs_clear_layoutreturn_info(struct pnfs_layout_hdr *lo)
 {
     struct pnfs_layout_segment *lseg;
     lo->plh_return_iomode = 0;
     lo->plh_return_seq = 0;
     clear_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags);
     list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
         if (!test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
             continue;
         pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
     }
 }
 
 static void pnfs_clear_layoutreturn_waitbit(struct pnfs_layout_hdr *lo)
 {
     clear_bit_unlock(NFS_LAYOUT_RETURN, &lo->plh_flags);
     clear_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags);
     smp_mb__after_atomic();
     wake_up_bit(&lo->plh_flags, NFS_LAYOUT_RETURN);
     rpc_wake_up(&NFS_SERVER(lo->plh_inode)->roc_rpcwaitq);
 }
 
 static void
 pnfs_clear_lseg_state(struct pnfs_layout_segment *lseg,
         struct list_head *free_me)
 {
     clear_bit(NFS_LSEG_ROC, &lseg->pls_flags);
     clear_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
     if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags))
         pnfs_lseg_dec_and_remove_zero(lseg, free_me);
     if (test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
         pnfs_lseg_dec_and_remove_zero(lseg, free_me);
 }
 
 /*
  * Update the seqid of a layout stateid after receiving
  * NFS4ERR_OLD_STATEID
  */
 bool nfs4_layout_refresh_old_stateid(nfs4_stateid *dst,
         struct pnfs_layout_range *dst_range,
         struct inode *inode)
 {
     struct pnfs_layout_hdr *lo;
     struct pnfs_layout_range range = {
         .iomode = IOMODE_ANY,
         .offset = 0,
         .length = NFS4_MAX_UINT64,
     };
     bool ret = false;
     LIST_HEAD(head);
     int err;
 
     spin_lock(&inode->i_lock);
     lo = NFS_I(inode)->layout;
     if (lo &&  pnfs_layout_is_valid(lo) &&
         nfs4_stateid_match_other(dst, &lo->plh_stateid)) {
         /* Is our call using the most recent seqid? If so, bump it */
         if (!nfs4_stateid_is_newer(&lo->plh_stateid, dst)) {
             nfs4_stateid_seqid_inc(dst);
             ret = true;
             goto out;
         }
         /* Try to update the seqid to the most recent */
         err = pnfs_mark_matching_lsegs_return(lo, &head, &range, 0);
         if (err != -EBUSY) {
             dst->seqid = lo->plh_stateid.seqid;
             *dst_range = range;
             ret = true;
         }
     }
 out:
     spin_unlock(&inode->i_lock);
     pnfs_free_lseg_list(&head);
     return ret;
 }
 
 /*
  * Mark a pnfs_layout_hdr and all associated layout segments as invalid
  *
  * In order to continue using the pnfs_layout_hdr, a full recovery
  * is required.
  * Note that caller must hold inode->i_lock.
  */
 int
 pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
         struct list_head *lseg_list)
 {
     struct pnfs_layout_range range = {
         .iomode = IOMODE_ANY,
         .offset = 0,
         .length = NFS4_MAX_UINT64,
     };
     struct pnfs_layout_segment *lseg, *next;
 
     set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
     list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
         pnfs_clear_lseg_state(lseg, lseg_list);
     pnfs_clear_layoutreturn_info(lo);
     pnfs_free_returned_lsegs(lo, lseg_list, &range, 0);
     set_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags);
     if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags) &&
         !test_and_set_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags))
         pnfs_clear_layoutreturn_waitbit(lo);
     return !list_empty(&lo->plh_segs);
 }
 
 static int
 pnfs_iomode_to_fail_bit(u32 iomode)
 {
     return iomode == IOMODE_RW ?
         NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;
 }
 
 static void
 pnfs_layout_set_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
 {
     lo->plh_retry_timestamp = jiffies;
     if (!test_and_set_bit(fail_bit, &lo->plh_flags))
         refcount_inc(&lo->plh_refcount);
 }
 
 static void
 pnfs_layout_clear_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
 {
     if (test_and_clear_bit(fail_bit, &lo->plh_flags))
         refcount_dec(&lo->plh_refcount);
 }
 
 static void
 pnfs_layout_io_set_failed(struct pnfs_layout_hdr *lo, u32 iomode)
 {
     struct inode *inode = lo->plh_inode;
     struct pnfs_layout_range range = {
         .iomode = iomode,
         .offset = 0,
         .length = NFS4_MAX_UINT64,
     };
     LIST_HEAD(head);
 
     spin_lock(&inode->i_lock);
     pnfs_layout_set_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
     pnfs_mark_matching_lsegs_invalid(lo, &head, &range, 0);
     spin_unlock(&inode->i_lock);
     pnfs_free_lseg_list(&head);
     dprintk("%s Setting layout IOMODE_%s fail bit\n", __func__,
             iomode == IOMODE_RW ?  "RW" : "READ");
 }
 
 static bool
 pnfs_layout_io_test_failed(struct pnfs_layout_hdr *lo, u32 iomode)
 {
     unsigned long start, end;
     int fail_bit = pnfs_iomode_to_fail_bit(iomode);
 
     if (test_bit(fail_bit, &lo->plh_flags) == 0)
         return false;
     end = jiffies;
     start = end - PNFS_LAYOUTGET_RETRY_TIMEOUT;
     if (!time_in_range(lo->plh_retry_timestamp, start, end)) {
         /* It is time to retry the failed layoutgets */
         pnfs_layout_clear_fail_bit(lo, fail_bit);
         return false;
     }
     return true;
 }
 
 static void
 pnfs_init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg,
         const struct pnfs_layout_range *range,
         const nfs4_stateid *stateid)
 {
     INIT_LIST_HEAD(&lseg->pls_list);
     INIT_LIST_HEAD(&lseg->pls_lc_list);
     INIT_LIST_HEAD(&lseg->pls_commits);
     refcount_set(&lseg->pls_refcount, 1);
     set_bit(NFS_LSEG_VALID, &lseg->pls_flags);
     lseg->pls_layout = lo;
     lseg->pls_range = *range;
     lseg->pls_seq = be32_to_cpu(stateid->seqid);
 }
 
 static void pnfs_free_lseg(struct pnfs_layout_segment *lseg)
 {
     if (lseg != NULL) {
         struct inode *inode = lseg->pls_layout->plh_inode;
         NFS_SERVER(inode)->pnfs_curr_ld->free_lseg(lseg);
     }
 }
 
 static void
 pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
         struct pnfs_layout_segment *lseg)
 {
     WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
     list_del_init(&lseg->pls_list);
     /* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
     refcount_dec(&lo->plh_refcount);
     if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
         return;
     if (list_empty(&lo->plh_segs) &&
         !test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) &&
         !test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
         if (atomic_read(&lo->plh_outstanding) == 0)
             set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
         clear_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
     }
 }
 
 static bool
 pnfs_cache_lseg_for_layoutreturn(struct pnfs_layout_hdr *lo,
         struct pnfs_layout_segment *lseg)
 {
     if (test_and_clear_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags) &&
         pnfs_layout_is_valid(lo)) {
         pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
         list_move_tail(&lseg->pls_list, &lo->plh_return_segs);
         return true;
     }
     return false;
 }
 
 void
 pnfs_put_lseg(struct pnfs_layout_segment *lseg)
 {
     struct pnfs_layout_hdr *lo;
     struct inode *inode;
 
     if (!lseg)
         return;
 
     dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
         refcount_read(&lseg->pls_refcount),
         test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
 
     lo = lseg->pls_layout;
     inode = lo->plh_inode;
 
     if (refcount_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
         pnfs_get_layout_hdr(lo);
         pnfs_layout_remove_lseg(lo, lseg);
         if (pnfs_cache_lseg_for_layoutreturn(lo, lseg))
             lseg = NULL;
         spin_unlock(&inode->i_lock);
         pnfs_free_lseg(lseg);
         pnfs_put_layout_hdr(lo);
     }
 }
 EXPORT_SYMBOL_GPL(pnfs_put_lseg);
 
 /*
  * is l2 fully contained in l1?
  *   start1                             end1
  *   [----------------------------------)
  *           start2           end2
  *           [----------------)
  */
 static bool
 pnfs_lseg_range_contained(const struct pnfs_layout_range *l1,
          const struct pnfs_layout_range *l2)
 {
     u64 start1 = l1->offset;
     u64 end1 = pnfs_end_offset(start1, l1->length);
     u64 start2 = l2->offset;
     u64 end2 = pnfs_end_offset(start2, l2->length);
 
     return (start1 <= start2) && (end1 >= end2);
 }
 
 static bool pnfs_lseg_dec_and_remove_zero(struct pnfs_layout_segment *lseg,
         struct list_head *tmp_list)
 {
     if (!refcount_dec_and_test(&lseg->pls_refcount))
         return false;
     pnfs_layout_remove_lseg(lseg->pls_layout, lseg);
     list_add(&lseg->pls_list, tmp_list);
     return true;
 }
 
 /* Returns 1 if lseg is removed from list, 0 otherwise */
 static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
                  struct list_head *tmp_list)
 {
     int rv = 0;
 
     if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
         /* Remove the reference keeping the lseg in the
          * list.  It will now be removed when all
          * outstanding io is finished.
          */
         dprintk("%s: lseg %p ref %d\n", __func__, lseg,
             refcount_read(&lseg->pls_refcount));
         if (pnfs_lseg_dec_and_remove_zero(lseg, tmp_list))
             rv = 1;
     }
     return rv;
 }
 
 static bool
 pnfs_should_free_range(const struct pnfs_layout_range *lseg_range,
          const struct pnfs_layout_range *recall_range)
 {
     return (recall_range->iomode == IOMODE_ANY ||
         lseg_range->iomode == recall_range->iomode) &&
            pnfs_lseg_range_intersecting(lseg_range, recall_range);
 }
 
 static bool
 pnfs_match_lseg_recall(const struct pnfs_layout_segment *lseg,
         const struct pnfs_layout_range *recall_range,
         u32 seq)
 {
     if (seq != 0 && pnfs_seqid_is_newer(lseg->pls_seq, seq))
         return false;
     if (recall_range == NULL)
         return true;
     return pnfs_should_free_range(&lseg->pls_range, recall_range);
 }
 
 /**
  * pnfs_mark_matching_lsegs_invalid - tear down lsegs or mark them for later
  * @lo: layout header containing the lsegs
  * @tmp_list: list head where doomed lsegs should go
  * @recall_range: optional recall range argument to match (may be NULL)
  * @seq: only invalidate lsegs obtained prior to this sequence (may be 0)
  *
  * Walk the list of lsegs in the layout header, and tear down any that should
  * be destroyed. If "recall_range" is specified then the segment must match
  * that range. If "seq" is non-zero, then only match segments that were handed
  * out at or before that sequence.
  *
  * Returns number of matching invalid lsegs remaining in list after scanning
  * it and purging them.
  */
 int
 pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
                 struct list_head *tmp_list,
                 const struct pnfs_layout_range *recall_range,
                 u32 seq)
 {
     struct pnfs_layout_segment *lseg, *next;
     int remaining = 0;
 
     dprintk("%s:Begin lo %p\n", __func__, lo);
 
     if (list_empty(&lo->plh_segs))
         return 0;
     list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
         if (pnfs_match_lseg_recall(lseg, recall_range, seq)) {
             dprintk("%s: freeing lseg %p iomode %d seq %u "
                 "offset %llu length %llu\n", __func__,
                 lseg, lseg->pls_range.iomode, lseg->pls_seq,
                 lseg->pls_range.offset, lseg->pls_range.length);
             if (!mark_lseg_invalid(lseg, tmp_list))
                 remaining++;
         }
     dprintk("%s:Return %i\n", __func__, remaining);
     return remaining;
 }
 
 static void
 pnfs_free_returned_lsegs(struct pnfs_layout_hdr *lo,
         struct list_head *free_me,
         const struct pnfs_layout_range *range,
         u32 seq)
 {
     struct pnfs_layout_segment *lseg, *next;
 
     list_for_each_entry_safe(lseg, next, &lo->plh_return_segs, pls_list) {
         if (pnfs_match_lseg_recall(lseg, range, seq))
             list_move_tail(&lseg->pls_list, free_me);
     }
 }
 
 /* note free_me must contain lsegs from a single layout_hdr */
 void
 pnfs_free_lseg_list(struct list_head *free_me)
 {
     struct pnfs_layout_segment *lseg, *tmp;
 
     if (list_empty(free_me))
         return;
 
     list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
         list_del(&lseg->pls_list);
         pnfs_free_lseg(lseg);
     }
 }
 
 static struct pnfs_layout_hdr *__pnfs_destroy_layout(struct nfs_inode *nfsi)
 {
     struct pnfs_layout_hdr *lo;
     LIST_HEAD(tmp_list);
 
     spin_lock(&nfsi->vfs_inode.i_lock);
     lo = nfsi->layout;
     if (lo) {
         pnfs_get_layout_hdr(lo);
         pnfs_mark_layout_stateid_invalid(lo, &tmp_list);
         pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
         pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
         spin_unlock(&nfsi->vfs_inode.i_lock);
         pnfs_free_lseg_list(&tmp_list);
         nfs_commit_inode(&nfsi->vfs_inode, 0);
         pnfs_put_layout_hdr(lo);
     } else
         spin_unlock(&nfsi->vfs_inode.i_lock);
     return lo;
 }
 
 void pnfs_destroy_layout(struct nfs_inode *nfsi)
 {
     __pnfs_destroy_layout(nfsi);
 }
 EXPORT_SYMBOL_GPL(pnfs_destroy_layout);
 
 static bool pnfs_layout_removed(struct nfs_inode *nfsi,
                 struct pnfs_layout_hdr *lo)
 {
     bool ret;
 
     spin_lock(&nfsi->vfs_inode.i_lock);
     ret = nfsi->layout != lo;
     spin_unlock(&nfsi->vfs_inode.i_lock);
     return ret;
 }
 
 void pnfs_destroy_layout_final(struct nfs_inode *nfsi)
 {
     struct pnfs_layout_hdr *lo = __pnfs_destroy_layout(nfsi);
 
     if (lo)
         wait_var_event(lo, pnfs_layout_removed(nfsi, lo));
 }
 
 static bool
 pnfs_layout_add_bulk_destroy_list(struct inode *inode,
         struct list_head *layout_list)
 {
     struct pnfs_layout_hdr *lo;
     bool ret = false;
 
     spin_lock(&inode->i_lock);
     lo = NFS_I(inode)->layout;
     if (lo != NULL && list_empty(&lo->plh_bulk_destroy)) {
         pnfs_get_layout_hdr(lo);
         list_add(&lo->plh_bulk_destroy, layout_list);
         ret = true;
     }
     spin_unlock(&inode->i_lock);
     return ret;
 }
 
 /* Caller must hold rcu_read_lock and clp->cl_lock */
 static int
 pnfs_layout_bulk_destroy_byserver_locked(struct nfs_client *clp,
         struct nfs_server *server,
         struct list_head *layout_list)
     __must_hold(&clp->cl_lock)
     __must_hold(RCU)
 {
     struct pnfs_layout_hdr *lo, *next;
     struct inode *inode;
 
     list_for_each_entry_safe(lo, next, &server->layouts, plh_layouts) {
         if (test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags) ||
             test_bit(NFS_LAYOUT_INODE_FREEING, &lo->plh_flags) ||
             !list_empty(&lo->plh_bulk_destroy))
             continue;
         /* If the sb is being destroyed, just bail */
         if (!nfs_sb_active(server->super))
             break;
         inode = pnfs_grab_inode_layout_hdr(lo);
         if (inode != NULL) {
             if (test_and_clear_bit(NFS_LAYOUT_HASHED, &lo->plh_flags))
                 list_del_rcu(&lo->plh_layouts);
             if (pnfs_layout_add_bulk_destroy_list(inode,
                         layout_list))
                 continue;
             rcu_read_unlock();
             spin_unlock(&clp->cl_lock);
             iput(inode);
         } else {
             rcu_read_unlock();
             spin_unlock(&clp->cl_lock);
         }
         nfs_sb_deactive(server->super);
         spin_lock(&clp->cl_lock);
         rcu_read_lock();
         return -EAGAIN;
     }
     return 0;
 }
 
 static int
 pnfs_layout_free_bulk_destroy_list(struct list_head *layout_list,
         bool is_bulk_recall)
 {
     struct pnfs_layout_hdr *lo;
     struct inode *inode;
     LIST_HEAD(lseg_list);
     int ret = 0;
 
     while (!list_empty(layout_list)) {
         lo = list_entry(layout_list->next, struct pnfs_layout_hdr,
                 plh_bulk_destroy);
         dprintk("%s freeing layout for inode %lu\n", __func__,
             lo->plh_inode->i_ino);
         inode = lo->plh_inode;
 
         pnfs_layoutcommit_inode(inode, false);
 
         spin_lock(&inode->i_lock);
         list_del_init(&lo->plh_bulk_destroy);
         if (pnfs_mark_layout_stateid_invalid(lo, &lseg_list)) {
             if (is_bulk_recall)
                 set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
             ret = -EAGAIN;
         }
         spin_unlock(&inode->i_lock);
         pnfs_free_lseg_list(&lseg_list);
         /* Free all lsegs that are attached to commit buckets */
         nfs_commit_inode(inode, 0);
         pnfs_put_layout_hdr(lo);
         nfs_iput_and_deactive(inode);
     }
     return ret;
 }
 
 int
 pnfs_destroy_layouts_byfsid(struct nfs_client *clp,
         struct nfs_fsid *fsid,
         bool is_recall)
 {
     struct nfs_server *server;
     LIST_HEAD(layout_list);
 
     spin_lock(&clp->cl_lock);
     rcu_read_lock();
 restart:
     list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
         if (memcmp(&server->fsid, fsid, sizeof(*fsid)) != 0)
             continue;
         if (pnfs_layout_bulk_destroy_byserver_locked(clp,
                 server,
                 &layout_list) != 0)
             goto restart;
     }
     rcu_read_unlock();
     spin_unlock(&clp->cl_lock);
 
     if (list_empty(&layout_list))
         return 0;
     return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
 }
 
 int
 pnfs_destroy_layouts_byclid(struct nfs_client *clp,
         bool is_recall)
 {
     struct nfs_server *server;
     LIST_HEAD(layout_list);
 
     spin_lock(&clp->cl_lock);
     rcu_read_lock();
 restart:
     list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
         if (pnfs_layout_bulk_destroy_byserver_locked(clp,
                     server,
                     &layout_list) != 0)
             goto restart;
     }
     rcu_read_unlock();
     spin_unlock(&clp->cl_lock);
 
     if (list_empty(&layout_list))
         return 0;
     return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
 }
 
 /*
  * Called by the state manager to remove all layouts established under an
  * expired lease.
  */
 void
 pnfs_destroy_all_layouts(struct nfs_client *clp)
 {
     nfs4_deviceid_mark_client_invalid(clp);
     nfs4_deviceid_purge_client(clp);
 
     pnfs_destroy_layouts_byclid(clp, false);
 }
 
 static void
 pnfs_set_layout_cred(struct pnfs_layout_hdr *lo, const struct cred *cred)
 {
     const struct cred *old;
 
     if (cred && cred_fscmp(lo->plh_lc_cred, cred) != 0) {
         old = xchg(&lo->plh_lc_cred, get_cred(cred));
         put_cred(old);
     }
 }
 
 /* update lo->plh_stateid with new if is more recent */
 void
 pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
             const struct cred *cred, bool update_barrier)
 {
     u32 oldseq = be32_to_cpu(lo->plh_stateid.seqid);
     u32 newseq = be32_to_cpu(new->seqid);
 
     if (!pnfs_layout_is_valid(lo)) {
         pnfs_set_layout_cred(lo, cred);
         nfs4_stateid_copy(&lo->plh_stateid, new);
         lo->plh_barrier = newseq;
         pnfs_clear_layoutreturn_info(lo);
         clear_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
         return;
     }
 
     if (pnfs_seqid_is_newer(newseq, oldseq))
         nfs4_stateid_copy(&lo->plh_stateid, new);
 
     if (update_barrier) {
         pnfs_barrier_update(lo, newseq);
         return;
     }
     /*
      * Because of wraparound, we want to keep the barrier
      * "close" to the current seqids. We really only want to
      * get here from a layoutget call.
      */
     if (atomic_read(&lo->plh_outstanding) == 1)
          pnfs_barrier_update(lo, be32_to_cpu(lo->plh_stateid.seqid));
 }
 
 static bool
 pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,
         const nfs4_stateid *stateid)
 {
     u32 seqid = be32_to_cpu(stateid->seqid);
 
     return lo->plh_barrier && pnfs_seqid_is_newer(lo->plh_barrier, seqid);
 }
 
 /* lget is set to 1 if called from inside send_layoutget call chain */
 static bool
 pnfs_layoutgets_blocked(const struct pnfs_layout_hdr *lo)
 {
     return lo->plh_block_lgets ||
         test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
 }
 
 static struct nfs_server *
 pnfs_find_server(struct inode *inode, struct nfs_open_context *ctx)
 {
     struct nfs_server *server;
 
     if (inode) {
         server = NFS_SERVER(inode);
     } else {
         struct dentry *parent_dir = dget_parent(ctx->dentry);
         server = NFS_SERVER(parent_dir->d_inode);
         dput(parent_dir);
     }
     return server;
 }
 
 static void nfs4_free_pages(struct page **pages, size_t size)
 {
     int i;
 
     if (!pages)
         return;
 
     for (i = 0; i < size; i++) {
         if (!pages[i])
             break;
         __free_page(pages[i]);
     }
     kfree(pages);
 }
 
 static struct page **nfs4_alloc_pages(size_t size, gfp_t gfp_flags)
 {
     struct page **pages;
     int i;
 
     pages = kmalloc_array(size, sizeof(struct page *), gfp_flags);
     if (!pages) {
         dprintk("%s: can't alloc array of %zu pages\n", __func__, size);
         return NULL;
     }
 
     for (i = 0; i < size; i++) {
         pages[i] = alloc_page(gfp_flags);
         if (!pages[i]) {
             dprintk("%s: failed to allocate page\n", __func__);
             nfs4_free_pages(pages, i);
             return NULL;
         }
     }
 
     return pages;
 }
 
 static struct nfs4_layoutget *
 pnfs_alloc_init_layoutget_args(struct inode *ino,
        struct nfs_open_context *ctx,
        const nfs4_stateid *stateid,
        const struct pnfs_layout_range *range,
        gfp_t gfp_flags)
 {
     struct nfs_server *server = pnfs_find_server(ino, ctx);
     size_t max_reply_sz = server->pnfs_curr_ld->max_layoutget_response;
     size_t max_pages = max_response_pages(server);
     struct nfs4_layoutget *lgp;
 
     dprintk("--> %s\n", __func__);
 
     lgp = kzalloc(sizeof(*lgp), gfp_flags);
     if (lgp == NULL)
         return NULL;
 
     if (max_reply_sz) {
         size_t npages = (max_reply_sz + PAGE_SIZE - 1) >> PAGE_SHIFT;
         if (npages < max_pages)
             max_pages = npages;
     }
 
     lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
     if (!lgp->args.layout.pages) {
         kfree(lgp);
         return NULL;
     }
     lgp->args.layout.pglen = max_pages * PAGE_SIZE;
     lgp->res.layoutp = &lgp->args.layout;
 
     /* Don't confuse uninitialised result and success */
     lgp->res.status = -NFS4ERR_DELAY;
 
     lgp->args.minlength = PAGE_SIZE;
     if (lgp->args.minlength > range->length)
         lgp->args.minlength = range->length;
     if (ino) {
         loff_t i_size = i_size_read(ino);
 
         if (range->iomode == IOMODE_READ) {
             if (range->offset >= i_size)
                 lgp->args.minlength = 0;
             else if (i_size - range->offset < lgp->args.minlength)
                 lgp->args.minlength = i_size - range->offset;
         }
     }
     lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
     pnfs_copy_range(&lgp->args.range, range);
     lgp->args.type = server->pnfs_curr_ld->id;
     lgp->args.inode = ino;
     lgp->args.ctx = get_nfs_open_context(ctx);
     nfs4_stateid_copy(&lgp->args.stateid, stateid);
     lgp->gfp_flags = gfp_flags;
     lgp->cred = ctx->cred;
     return lgp;
 }
 
 void pnfs_layoutget_free(struct nfs4_layoutget *lgp)
 {
     size_t max_pages = lgp->args.layout.pglen / PAGE_SIZE;
 
     nfs4_free_pages(lgp->args.layout.pages, max_pages);
     pnfs_put_layout_hdr(lgp->lo);
     put_nfs_open_context(lgp->args.ctx);
     kfree(lgp);
 }
 
 static void pnfs_clear_layoutcommit(struct inode *inode,
         struct list_head *head)
 {
     struct nfs_inode *nfsi = NFS_I(inode);
     struct pnfs_layout_segment *lseg, *tmp;
 
     if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
         return;
     list_for_each_entry_safe(lseg, tmp, &nfsi->layout->plh_segs, pls_list) {
         if (!test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
             continue;
         pnfs_lseg_dec_and_remove_zero(lseg, head);
     }
 }
 
 void pnfs_layoutreturn_free_lsegs(struct pnfs_layout_hdr *lo,
         const nfs4_stateid *arg_stateid,
         const struct pnfs_layout_range *range,
         const nfs4_stateid *stateid)
 {
     struct inode *inode = lo->plh_inode;
     LIST_HEAD(freeme);
 
     spin_lock(&inode->i_lock);
     if (!pnfs_layout_is_valid(lo) ||
         !nfs4_stateid_match_other(&lo->plh_stateid, arg_stateid))
         goto out_unlock;
     if (stateid) {
         u32 seq = be32_to_cpu(arg_stateid->seqid);
 
         pnfs_mark_matching_lsegs_invalid(lo, &freeme, range, seq);
         pnfs_free_returned_lsegs(lo, &freeme, range, seq);
         pnfs_set_layout_stateid(lo, stateid, NULL, true);
     } else
         pnfs_mark_layout_stateid_invalid(lo, &freeme);
 out_unlock:
     pnfs_clear_layoutreturn_waitbit(lo);
     spin_unlock(&inode->i_lock);
     pnfs_free_lseg_list(&freeme);
 
 }
 
 static bool
 pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo,
         nfs4_stateid *stateid,
         const struct cred **cred,
         enum pnfs_iomode *iomode)
 {
     /* Serialise LAYOUTGET/LAYOUTRETURN */
     if (atomic_read(&lo->plh_outstanding) != 0)
         return false;
     if (test_and_set_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags))
         return false;
     set_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
     pnfs_get_layout_hdr(lo);
     nfs4_stateid_copy(stateid, &lo->plh_stateid);
     *cred = get_cred(lo->plh_lc_cred);
     if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags)) {
         if (lo->plh_return_seq != 0)
             stateid->seqid = cpu_to_be32(lo->plh_return_seq);
         if (iomode != NULL)
             *iomode = lo->plh_return_iomode;
         pnfs_clear_layoutreturn_info(lo);
     } else if (iomode != NULL)
         *iomode = IOMODE_ANY;
     pnfs_barrier_update(lo, be32_to_cpu(stateid->seqid));
     return true;
 }
 
 static void
 pnfs_init_layoutreturn_args(struct nfs4_layoutreturn_args *args,
         struct pnfs_layout_hdr *lo,
         const nfs4_stateid *stateid,
         enum pnfs_iomode iomode)
 {
     struct inode *inode = lo->plh_inode;
 
     args->layout_type = NFS_SERVER(inode)->pnfs_curr_ld->id;
     args->inode = inode;
     args->range.iomode = iomode;
     args->range.offset = 0;
     args->range.length = NFS4_MAX_UINT64;
     args->layout = lo;
     nfs4_stateid_copy(&args->stateid, stateid);
 }
 
 static int
 pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo,
                const nfs4_stateid *stateid,
                const struct cred **pcred,
                enum pnfs_iomode iomode,
                bool sync)
 {
     struct inode *ino = lo->plh_inode;
     struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
     struct nfs4_layoutreturn *lrp;
     const struct cred *cred = *pcred;
     int status = 0;
 
     *pcred = NULL;
     lrp = kzalloc(sizeof(*lrp), nfs_io_gfp_mask());
     if (unlikely(lrp == NULL)) {
         status = -ENOMEM;
         spin_lock(&ino->i_lock);
         pnfs_clear_layoutreturn_waitbit(lo);
         spin_unlock(&ino->i_lock);
         put_cred(cred);
         pnfs_put_layout_hdr(lo);
         goto out;
     }
 
     pnfs_init_layoutreturn_args(&lrp->args, lo, stateid, iomode);
     lrp->args.ld_private = &lrp->ld_private;
     lrp->clp = NFS_SERVER(ino)->nfs_client;
     lrp->cred = cred;
     if (ld->prepare_layoutreturn)
         ld->prepare_layoutreturn(&lrp->args);
 
     status = nfs4_proc_layoutreturn(lrp, sync);
 out:
     dprintk("<-- %s status: %d\n", __func__, status);
     return status;
 }
 
 static bool
 pnfs_layout_segments_returnable(struct pnfs_layout_hdr *lo,
                 enum pnfs_iomode iomode,
                 u32 seq)
 {
     struct pnfs_layout_range recall_range = {
         .length = NFS4_MAX_UINT64,
         .iomode = iomode,
     };
     return pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs,
                            &recall_range, seq) != -EBUSY;
 }
 
 /* Return true if layoutreturn is needed */
 static bool
 pnfs_layout_need_return(struct pnfs_layout_hdr *lo)
 {
     if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
         return false;
     return pnfs_layout_segments_returnable(lo, lo->plh_return_iomode,
                            lo->plh_return_seq);
 }
 
 static void pnfs_layoutreturn_before_put_layout_hdr(struct pnfs_layout_hdr *lo)
 {
     struct inode *inode= lo->plh_inode;
 
     if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
         return;
     spin_lock(&inode->i_lock);
     if (pnfs_layout_need_return(lo)) {
         const struct cred *cred;
         nfs4_stateid stateid;
         enum pnfs_iomode iomode;
         bool send;
 
         send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
         spin_unlock(&inode->i_lock);
         if (send) {
             /* Send an async layoutreturn so we dont deadlock */
             pnfs_send_layoutreturn(lo, &stateid, &cred, iomode, false);
         }
     } else
         spin_unlock(&inode->i_lock);
 }
 
 /*
  * Initiates a LAYOUTRETURN(FILE), and removes the pnfs_layout_hdr
  * when the layout segment list is empty.
  *
  * Note that a pnfs_layout_hdr can exist with an empty layout segment
  * list when LAYOUTGET has failed, or when LAYOUTGET succeeded, but the
  * deviceid is marked invalid.
  */
 int
 _pnfs_return_layout(struct inode *ino)
 {
     struct pnfs_layout_hdr *lo = NULL;
     struct nfs_inode *nfsi = NFS_I(ino);
     struct pnfs_layout_range range = {
         .iomode     = IOMODE_ANY,
         .offset     = 0,
         .length     = NFS4_MAX_UINT64,
     };
     LIST_HEAD(tmp_list);
     const struct cred *cred;
     nfs4_stateid stateid;
     int status = 0;
     bool send, valid_layout;
 
     dprintk("NFS: %s for inode %lu\n", __func__, ino->i_ino);
 
     spin_lock(&ino->i_lock);
     lo = nfsi->layout;
     if (!lo) {
         spin_unlock(&ino->i_lock);
         dprintk("NFS: %s no layout to return\n", __func__);
         goto out;
     }
     /* Reference matched in nfs4_layoutreturn_release */
     pnfs_get_layout_hdr(lo);
     /* Is there an outstanding layoutreturn ? */
     if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
         spin_unlock(&ino->i_lock);
         if (wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
                     TASK_UNINTERRUPTIBLE))
             goto out_put_layout_hdr;
         spin_lock(&ino->i_lock);
     }
     valid_layout = pnfs_layout_is_valid(lo);
     pnfs_clear_layoutcommit(ino, &tmp_list);
     pnfs_mark_matching_lsegs_return(lo, &tmp_list, &range, 0);
 
     if (NFS_SERVER(ino)->pnfs_curr_ld->return_range)
         NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo, &range);
 
     /* Don't send a LAYOUTRETURN if list was initially empty */
     if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) ||
             !valid_layout) {
         spin_unlock(&ino->i_lock);
         dprintk("NFS: %s no layout segments to return\n", __func__);
         goto out_wait_layoutreturn;
     }
 
     send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, NULL);
     spin_unlock(&ino->i_lock);
     if (send)
         status = pnfs_send_layoutreturn(lo, &stateid, &cred, IOMODE_ANY, true);
 out_wait_layoutreturn:
     wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN, TASK_UNINTERRUPTIBLE);
 out_put_layout_hdr:
     pnfs_free_lseg_list(&tmp_list);
     pnfs_put_layout_hdr(lo);
 out:
     dprintk("<-- %s status: %d\n", __func__, status);
     return status;
 }
 
 int
 pnfs_commit_and_return_layout(struct inode *inode)
 {
     struct pnfs_layout_hdr *lo;
     int ret;
 
     spin_lock(&inode->i_lock);
     lo = NFS_I(inode)->layout;
     if (lo == NULL) {
         spin_unlock(&inode->i_lock);
         return 0;
     }
     pnfs_get_layout_hdr(lo);
     /* Block new layoutgets and read/write to ds */
     lo->plh_block_lgets++;
     spin_unlock(&inode->i_lock);
     filemap_fdatawait(inode->i_mapping);
     ret = pnfs_layoutcommit_inode(inode, true);
     if (ret == 0)
         ret = _pnfs_return_layout(inode);
     spin_lock(&inode->i_lock);
     lo->plh_block_lgets--;
     spin_unlock(&inode->i_lock);
     pnfs_put_layout_hdr(lo);
     return ret;
 }
 
 bool pnfs_roc(struct inode *ino,
         struct nfs4_layoutreturn_args *args,
         struct nfs4_layoutreturn_res *res,
         const struct cred *cred)
 {
     struct nfs_inode *nfsi = NFS_I(ino);
     struct nfs_open_context *ctx;
     struct nfs4_state *state;
     struct pnfs_layout_hdr *lo;
     struct pnfs_layout_segment *lseg, *next;
     const struct cred *lc_cred;
     nfs4_stateid stateid;
     enum pnfs_iomode iomode = 0;
     bool layoutreturn = false, roc = false;
     bool skip_read = false;
 
     if (!nfs_have_layout(ino))
         return false;
 retry:
     rcu_read_lock();
     spin_lock(&ino->i_lock);
     lo = nfsi->layout;
     if (!lo || !pnfs_layout_is_valid(lo) ||
         test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
         lo = NULL;
         goto out_noroc;
     }
     pnfs_get_layout_hdr(lo);
     if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
         spin_unlock(&ino->i_lock);
         rcu_read_unlock();
         wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
                 TASK_UNINTERRUPTIBLE);
         pnfs_put_layout_hdr(lo);
         goto retry;
     }
 
     /* no roc if we hold a delegation */
     if (nfs4_check_delegation(ino, FMODE_READ)) {
         if (nfs4_check_delegation(ino, FMODE_WRITE))
             goto out_noroc;
         skip_read = true;
     }
 
     list_for_each_entry_rcu(ctx, &nfsi->open_files, list) {
         state = ctx->state;
         if (state == NULL)
             continue;
         /* Don't return layout if there is open file state */
         if (state->state & FMODE_WRITE)
             goto out_noroc;
         if (state->state & FMODE_READ)
             skip_read = true;
     }
 
 
     list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list) {
         if (skip_read && lseg->pls_range.iomode == IOMODE_READ)
             continue;
         /* If we are sending layoutreturn, invalidate all valid lsegs */
         if (!test_and_clear_bit(NFS_LSEG_ROC, &lseg->pls_flags))
             continue;
         /*
          * Note: mark lseg for return so pnfs_layout_remove_lseg
          * doesn't invalidate the layout for us.
          */
         set_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
         if (!mark_lseg_invalid(lseg, &lo->plh_return_segs))
             continue;
         pnfs_set_plh_return_info(lo, lseg->pls_range.iomode, 0);
     }
 
     if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
         goto out_noroc;
 
     /* ROC in two conditions:
      * 1. there are ROC lsegs
      * 2. we don't send layoutreturn
      */
     /* lo ref dropped in pnfs_roc_release() */
     layoutreturn = pnfs_prepare_layoutreturn(lo, &stateid, &lc_cred, &iomode);
     /* If the creds don't match, we can't compound the layoutreturn */
     if (!layoutreturn || cred_fscmp(cred, lc_cred) != 0)
         goto out_noroc;
 
     roc = layoutreturn;
     pnfs_init_layoutreturn_args(args, lo, &stateid, iomode);
     res->lrs_present = 0;
     layoutreturn = false;
     put_cred(lc_cred);
 
 out_noroc:
     spin_unlock(&ino->i_lock);
     rcu_read_unlock();
     pnfs_layoutcommit_inode(ino, true);
     if (roc) {
         struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
         if (ld->prepare_layoutreturn)
             ld->prepare_layoutreturn(args);
         pnfs_put_layout_hdr(lo);
         return true;
     }
     if (layoutreturn)
         pnfs_send_layoutreturn(lo, &stateid, &lc_cred, iomode, true);
     pnfs_put_layout_hdr(lo);
     return false;
 }
 
 int pnfs_roc_done(struct rpc_task *task, struct nfs4_layoutreturn_args **argpp,
           struct nfs4_layoutreturn_res **respp, int *ret)
 {
     struct nfs4_layoutreturn_args *arg = *argpp;
     int retval = -EAGAIN;
 
     if (!arg)
         return 0;
     /* Handle Layoutreturn errors */
     switch (*ret) {
     case 0:
         retval = 0;
         break;
     case -NFS4ERR_NOMATCHING_LAYOUT:
         /* Was there an RPC level error? If not, retry */
         if (task->tk_rpc_status == 0)
             break;
         /* If the call was not sent, let caller handle it */
         if (!RPC_WAS_SENT(task))
             return 0;
         /*
          * Otherwise, assume the call succeeded and
          * that we need to release the layout
          */
         *ret = 0;
         (*respp)->lrs_present = 0;
         retval = 0;
         break;
     case -NFS4ERR_DELAY:
         /* Let the caller handle the retry */
         *ret = -NFS4ERR_NOMATCHING_LAYOUT;
         return 0;
     case -NFS4ERR_OLD_STATEID:
         if (!nfs4_layout_refresh_old_stateid(&arg->stateid,
                              &arg->range, arg->inode))
             break;
         *ret = -NFS4ERR_NOMATCHING_LAYOUT;
         return -EAGAIN;
     }
     *argpp = NULL;
     *respp = NULL;
     return retval;
 }
 
 void pnfs_roc_release(struct nfs4_layoutreturn_args *args,
         struct nfs4_layoutreturn_res *res,
         int ret)
 {
     struct pnfs_layout_hdr *lo = args->layout;
     struct inode *inode = args->inode;
     const nfs4_stateid *res_stateid = NULL;
     struct nfs4_xdr_opaque_data *ld_private = args->ld_private;
 
     switch (ret) {
     case -NFS4ERR_NOMATCHING_LAYOUT:
         spin_lock(&inode->i_lock);
         if (pnfs_layout_is_valid(lo) &&
             nfs4_stateid_match_other(&args->stateid, &lo->plh_stateid))
             pnfs_set_plh_return_info(lo, args->range.iomode, 0);
         pnfs_clear_layoutreturn_waitbit(lo);
         spin_unlock(&inode->i_lock);
         break;
     case 0:
         if (res->lrs_present)
             res_stateid = &res->stateid;
         fallthrough;
     default:
         pnfs_layoutreturn_free_lsegs(lo, &args->stateid, &args->range,
                          res_stateid);
     }
     trace_nfs4_layoutreturn_on_close(args->inode, &args->stateid, ret);
     if (ld_private && ld_private->ops && ld_private->ops->free)
         ld_private->ops->free(ld_private);
     pnfs_put_layout_hdr(lo);
 }
 
 bool pnfs_wait_on_layoutreturn(struct inode *ino, struct rpc_task *task)
 {
     struct nfs_inode *nfsi = NFS_I(ino);
         struct pnfs_layout_hdr *lo;
         bool sleep = false;
 
     /* we might not have grabbed lo reference. so need to check under
      * i_lock */
         spin_lock(&ino->i_lock);
         lo = nfsi->layout;
         if (lo && test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
                 rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);
                 sleep = true;
     }
         spin_unlock(&ino->i_lock);
         return sleep;
 }
 
 /*
  * Compare two layout segments for sorting into layout cache.
  * We want to preferentially return RW over RO layouts, so ensure those
  * are seen first.
  */
 static s64
 pnfs_lseg_range_cmp(const struct pnfs_layout_range *l1,
        const struct pnfs_layout_range *l2)
 {
     s64 d;
 
     /* high offset > low offset */
     d = l1->offset - l2->offset;
     if (d)
         return d;
 
     /* short length > long length */
     d = l2->length - l1->length;
     if (d)
         return d;
 
     /* read > read/write */
     return (int)(l1->iomode == IOMODE_READ) - (int)(l2->iomode == IOMODE_READ);
 }
 
 static bool
 pnfs_lseg_range_is_after(const struct pnfs_layout_range *l1,
         const struct pnfs_layout_range *l2)
 {
     return pnfs_lseg_range_cmp(l1, l2) > 0;
 }
 
 static bool
 pnfs_lseg_no_merge(struct pnfs_layout_segment *lseg,
         struct pnfs_layout_segment *old)
 {
     return false;
 }
 
 void
 pnfs_generic_layout_insert_lseg(struct pnfs_layout_hdr *lo,
            struct pnfs_layout_segment *lseg,
            bool (*is_after)(const struct pnfs_layout_range *,
                const struct pnfs_layout_range *),
            bool (*do_merge)(struct pnfs_layout_segment *,
                struct pnfs_layout_segment *),
            struct list_head *free_me)
 {
     struct pnfs_layout_segment *lp, *tmp;
 
     dprintk("%s:Begin\n", __func__);
 
     list_for_each_entry_safe(lp, tmp, &lo->plh_segs, pls_list) {
         if (test_bit(NFS_LSEG_VALID, &lp->pls_flags) == 0)
             continue;
         if (do_merge(lseg, lp)) {
             mark_lseg_invalid(lp, free_me);
             continue;
         }
         if (is_after(&lseg->pls_range, &lp->pls_range))
             continue;
         list_add_tail(&lseg->pls_list, &lp->pls_list);
         dprintk("%s: inserted lseg %p "
             "iomode %d offset %llu length %llu before "
             "lp %p iomode %d offset %llu length %llu\n",
             __func__, lseg, lseg->pls_range.iomode,
             lseg->pls_range.offset, lseg->pls_range.length,
             lp, lp->pls_range.iomode, lp->pls_range.offset,
             lp->pls_range.length);
         goto out;
     }
     list_add_tail(&lseg->pls_list, &lo->plh_segs);
     dprintk("%s: inserted lseg %p "
         "iomode %d offset %llu length %llu at tail\n",
         __func__, lseg, lseg->pls_range.iomode,
         lseg->pls_range.offset, lseg->pls_range.length);
 out:
     pnfs_get_layout_hdr(lo);
 
     dprintk("%s:Return\n", __func__);
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_layout_insert_lseg);
 
 static void
 pnfs_layout_insert_lseg(struct pnfs_layout_hdr *lo,
            struct pnfs_layout_segment *lseg,
            struct list_head *free_me)
 {
     struct inode *inode = lo->plh_inode;
     struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
 
     if (ld->add_lseg != NULL)
         ld->add_lseg(lo, lseg, free_me);
     else
         pnfs_generic_layout_insert_lseg(lo, lseg,
                 pnfs_lseg_range_is_after,
                 pnfs_lseg_no_merge,
                 free_me);
 }
 
 static struct pnfs_layout_hdr *
 alloc_init_layout_hdr(struct inode *ino,
               struct nfs_open_context *ctx,
               gfp_t gfp_flags)
 {
     struct pnfs_layout_hdr *lo;
 
     lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
     if (!lo)
         return NULL;
     refcount_set(&lo->plh_refcount, 1);
     INIT_LIST_HEAD(&lo->plh_layouts);
     INIT_LIST_HEAD(&lo->plh_segs);
     INIT_LIST_HEAD(&lo->plh_return_segs);
     INIT_LIST_HEAD(&lo->plh_bulk_destroy);
     lo->plh_inode = ino;
     lo->plh_lc_cred = get_cred(ctx->cred);
     lo->plh_flags |= 1 << NFS_LAYOUT_INVALID_STID;
     return lo;
 }
 
 static struct pnfs_layout_hdr *
 pnfs_find_alloc_layout(struct inode *ino,
                struct nfs_open_context *ctx,
                gfp_t gfp_flags)
     __releases(&ino->i_lock)
     __acquires(&ino->i_lock)
 {
     struct nfs_inode *nfsi = NFS_I(ino);
     struct pnfs_layout_hdr *new = NULL;
 
     dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
 
     if (nfsi->layout != NULL)
         goto out_existing;
     spin_unlock(&ino->i_lock);
     new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
     spin_lock(&ino->i_lock);
 
     if (likely(nfsi->layout == NULL)) { /* Won the race? */
         nfsi->layout = new;
         return new;
     } else if (new != NULL)
         pnfs_free_layout_hdr(new);
 out_existing:
     pnfs_get_layout_hdr(nfsi->layout);
     return nfsi->layout;
 }
 
 /*
  * iomode matching rules:
  * iomode   lseg    strict match
  *                      iomode
  * -----    -----   ------ -----
  * ANY      READ    N/A    true
  * ANY      RW  N/A    true
  * RW       READ    N/A    false
  * RW       RW  N/A    true
  * READ     READ    N/A    true
  * READ     RW  true   false
  * READ     RW  false  true
  */
 static bool
 pnfs_lseg_range_match(const struct pnfs_layout_range *ls_range,
          const struct pnfs_layout_range *range,
          bool strict_iomode)
 {
     struct pnfs_layout_range range1;
 
     if ((range->iomode == IOMODE_RW &&
          ls_range->iomode != IOMODE_RW) ||
         (range->iomode != ls_range->iomode &&
          strict_iomode) ||
         !pnfs_lseg_range_intersecting(ls_range, range))
         return false;
 
     /* range1 covers only the first byte in the range */
     range1 = *range;
     range1.length = 1;
     return pnfs_lseg_range_contained(ls_range, &range1);
 }
 
 /*
  * lookup range in layout
  */
 static struct pnfs_layout_segment *
 pnfs_find_lseg(struct pnfs_layout_hdr *lo,
         struct pnfs_layout_range *range,
         bool strict_iomode)
 {
     struct pnfs_layout_segment *lseg, *ret = NULL;
 
     dprintk("%s:Begin\n", __func__);
 
     list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
         if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
             pnfs_lseg_range_match(&lseg->pls_range, range,
                       strict_iomode)) {
             ret = pnfs_get_lseg(lseg);
             break;
         }
     }
 
     dprintk("%s:Return lseg %p ref %d\n",
         __func__, ret, ret ? refcount_read(&ret->pls_refcount) : 0);
     return ret;
 }
 
 /*
  * Use mdsthreshold hints set at each OPEN to determine if I/O should go
  * to the MDS or over pNFS
  *
  * The nfs_inode read_io and write_io fields are cumulative counters reset
  * when there are no layout segments. Note that in pnfs_update_layout iomode
  * is set to IOMODE_READ for a READ request, and set to IOMODE_RW for a
  * WRITE request.
  *
  * A return of true means use MDS I/O.
  *
  * From rfc 5661:
  * If a file's size is smaller than the file size threshold, data accesses
  * SHOULD be sent to the metadata server.  If an I/O request has a length that
  * is below the I/O size threshold, the I/O SHOULD be sent to the metadata
  * server.  If both file size and I/O size are provided, the client SHOULD
  * reach or exceed  both thresholds before sending its read or write
  * requests to the data server.
  */
 static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx,
                      struct inode *ino, int iomode)
 {
     struct nfs4_threshold *t = ctx->mdsthreshold;
     struct nfs_inode *nfsi = NFS_I(ino);
     loff_t fsize = i_size_read(ino);
     bool size = false, size_set = false, io = false, io_set = false, ret = false;
 
     if (t == NULL)
         return ret;
 
     dprintk("%s bm=0x%x rd_sz=%llu wr_sz=%llu rd_io=%llu wr_io=%llu\n",
         __func__, t->bm, t->rd_sz, t->wr_sz, t->rd_io_sz, t->wr_io_sz);
 
     switch (iomode) {
     case IOMODE_READ:
         if (t->bm & THRESHOLD_RD) {
             dprintk("%s fsize %llu\n", __func__, fsize);
             size_set = true;
             if (fsize < t->rd_sz)
                 size = true;
         }
         if (t->bm & THRESHOLD_RD_IO) {
             dprintk("%s nfsi->read_io %llu\n", __func__,
                 nfsi->read_io);
             io_set = true;
             if (nfsi->read_io < t->rd_io_sz)
                 io = true;
         }
         break;
     case IOMODE_RW:
         if (t->bm & THRESHOLD_WR) {
             dprintk("%s fsize %llu\n", __func__, fsize);
             size_set = true;
             if (fsize < t->wr_sz)
                 size = true;
         }
         if (t->bm & THRESHOLD_WR_IO) {
             dprintk("%s nfsi->write_io %llu\n", __func__,
                 nfsi->write_io);
             io_set = true;
             if (nfsi->write_io < t->wr_io_sz)
                 io = true;
         }
         break;
     }
     if (size_set && io_set) {
         if (size && io)
             ret = true;
     } else if (size || io)
         ret = true;
 
     dprintk("<-- %s size %d io %d ret %d\n", __func__, size, io, ret);
     return ret;
 }
 
 static int pnfs_prepare_to_retry_layoutget(struct pnfs_layout_hdr *lo)
 {
     /*
      * send layoutcommit as it can hold up layoutreturn due to lseg
      * reference
      */
     pnfs_layoutcommit_inode(lo->plh_inode, false);
     return wait_on_bit_action(&lo->plh_flags, NFS_LAYOUT_RETURN,
                    nfs_wait_bit_killable,
                    TASK_KILLABLE);
 }
 
 static void nfs_layoutget_begin(struct pnfs_layout_hdr *lo)
 {
     atomic_inc(&lo->plh_outstanding);
 }
 
 static void nfs_layoutget_end(struct pnfs_layout_hdr *lo)
 {
     if (atomic_dec_and_test(&lo->plh_outstanding) &&
         test_and_clear_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags))
         wake_up_bit(&lo->plh_flags, NFS_LAYOUT_DRAIN);
 }
 
 static bool pnfs_is_first_layoutget(struct pnfs_layout_hdr *lo)
 {
     return test_bit(NFS_LAYOUT_FIRST_LAYOUTGET, &lo->plh_flags);
 }
 
 static void pnfs_clear_first_layoutget(struct pnfs_layout_hdr *lo)
 {
     unsigned long *bitlock = &lo->plh_flags;
 
     clear_bit_unlock(NFS_LAYOUT_FIRST_LAYOUTGET, bitlock);
     smp_mb__after_atomic();
     wake_up_bit(bitlock, NFS_LAYOUT_FIRST_LAYOUTGET);
 }
 
 static void _add_to_server_list(struct pnfs_layout_hdr *lo,
                 struct nfs_server *server)
 {
     if (!test_and_set_bit(NFS_LAYOUT_HASHED, &lo->plh_flags)) {
         struct nfs_client *clp = server->nfs_client;
 
         /* The lo must be on the clp list if there is any
          * chance of a CB_LAYOUTRECALL(FILE) coming in.
          */
         spin_lock(&clp->cl_lock);
         list_add_tail_rcu(&lo->plh_layouts, &server->layouts);
         spin_unlock(&clp->cl_lock);
     }
 }
 
 /*
  * Layout segment is retreived from the server if not cached.
  * The appropriate layout segment is referenced and returned to the caller.
  */
 struct pnfs_layout_segment *
 pnfs_update_layout(struct inode *ino,
            struct nfs_open_context *ctx,
            loff_t pos,
            u64 count,
            enum pnfs_iomode iomode,
            bool strict_iomode,
            gfp_t gfp_flags)
 {
     struct pnfs_layout_range arg = {
         .iomode = iomode,
         .offset = pos,
         .length = count,
     };
     unsigned pg_offset;
     struct nfs_server *server = NFS_SERVER(ino);
     struct nfs_client *clp = server->nfs_client;
     struct pnfs_layout_hdr *lo = NULL;
     struct pnfs_layout_segment *lseg = NULL;
     struct nfs4_layoutget *lgp;
     nfs4_stateid stateid;
     long timeout = 0;
     unsigned long giveup = jiffies + (clp->cl_lease_time << 1);
     bool first;
 
     if (!pnfs_enabled_sb(NFS_SERVER(ino))) {
         trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                  PNFS_UPDATE_LAYOUT_NO_PNFS);
         goto out;
     }
 
     if (pnfs_within_mdsthreshold(ctx, ino, iomode)) {
         trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                  PNFS_UPDATE_LAYOUT_MDSTHRESH);
         goto out;
     }
 
 lookup_again:
     lseg = ERR_PTR(nfs4_client_recover_expired_lease(clp));
     if (IS_ERR(lseg))
         goto out;
     first = false;
     spin_lock(&ino->i_lock);
     lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
     if (lo == NULL) {
         spin_unlock(&ino->i_lock);
         lseg = ERR_PTR(-ENOMEM);
         trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                  PNFS_UPDATE_LAYOUT_NOMEM);
         goto out;
     }
 
     /* Do we even need to bother with this? */
     if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
         trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                  PNFS_UPDATE_LAYOUT_BULK_RECALL);
         dprintk("%s matches recall, use MDS\n", __func__);
         goto out_unlock;
     }
 
     /* if LAYOUTGET already failed once we don't try again */
     if (pnfs_layout_io_test_failed(lo, iomode)) {
         trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                  PNFS_UPDATE_LAYOUT_IO_TEST_FAIL);
         goto out_unlock;
     }
 
     /*
      * If the layout segment list is empty, but there are outstanding
      * layoutget calls, then they might be subject to a layoutrecall.
      */
     if (test_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags) &&
         atomic_read(&lo->plh_outstanding) != 0) {
         spin_unlock(&ino->i_lock);
         lseg = ERR_PTR(wait_on_bit(&lo->plh_flags, NFS_LAYOUT_DRAIN,
                        TASK_KILLABLE));
         if (IS_ERR(lseg))
             goto out_put_layout_hdr;
         pnfs_put_layout_hdr(lo);
         goto lookup_again;
     }
 
     /*
      * Because we free lsegs when sending LAYOUTRETURN, we need to wait
      * for LAYOUTRETURN.
      */
     if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
         spin_unlock(&ino->i_lock);
         dprintk("%s wait for layoutreturn\n", __func__);
         lseg = ERR_PTR(pnfs_prepare_to_retry_layoutget(lo));
         if (!IS_ERR(lseg)) {
             pnfs_put_layout_hdr(lo);
             dprintk("%s retrying\n", __func__);
             trace_pnfs_update_layout(ino, pos, count, iomode, lo,
                          lseg,
                          PNFS_UPDATE_LAYOUT_RETRY);
             goto lookup_again;
         }
         trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                      PNFS_UPDATE_LAYOUT_RETURN);
         goto out_put_layout_hdr;
     }
 
     lseg = pnfs_find_lseg(lo, &arg, strict_iomode);
     if (lseg) {
         trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                 PNFS_UPDATE_LAYOUT_FOUND_CACHED);
         goto out_unlock;
     }
 
     /*
      * Choose a stateid for the LAYOUTGET. If we don't have a layout
      * stateid, or it has been invalidated, then we must use the open
      * stateid.
      */
     if (test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags)) {
         int status;
 
         /*
          * The first layoutget for the file. Need to serialize per
          * RFC 5661 Errata 3208.
          */
         if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET,
                      &lo->plh_flags)) {
             spin_unlock(&ino->i_lock);
             lseg = ERR_PTR(wait_on_bit(&lo->plh_flags,
                         NFS_LAYOUT_FIRST_LAYOUTGET,
                         TASK_KILLABLE));
             if (IS_ERR(lseg))
                 goto out_put_layout_hdr;
             pnfs_put_layout_hdr(lo);
             dprintk("%s retrying\n", __func__);
             goto lookup_again;
         }
 
         spin_unlock(&ino->i_lock);
         first = true;
         status = nfs4_select_rw_stateid(ctx->state,
                     iomode == IOMODE_RW ? FMODE_WRITE : FMODE_READ,
                     NULL, &stateid, NULL);
         if (status != 0) {
             lseg = ERR_PTR(status);
             trace_pnfs_update_layout(ino, pos, count,
                     iomode, lo, lseg,
                     PNFS_UPDATE_LAYOUT_INVALID_OPEN);
             nfs4_schedule_stateid_recovery(server, ctx->state);
             pnfs_clear_first_layoutget(lo);
             pnfs_put_layout_hdr(lo);
             goto lookup_again;
         }
         spin_lock(&ino->i_lock);
     } else {
         nfs4_stateid_copy(&stateid, &lo->plh_stateid);
     }
 
     if (pnfs_layoutgets_blocked(lo)) {
         trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                 PNFS_UPDATE_LAYOUT_BLOCKED);
         goto out_unlock;
     }
     nfs_layoutget_begin(lo);
     spin_unlock(&ino->i_lock);
 
     _add_to_server_list(lo, server);
 
     pg_offset = arg.offset & ~PAGE_MASK;
     if (pg_offset) {
         arg.offset -= pg_offset;
         arg.length += pg_offset;
     }
     if (arg.length != NFS4_MAX_UINT64)
         arg.length = PAGE_ALIGN(arg.length);
 
     lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &stateid, &arg, gfp_flags);
     if (!lgp) {
         lseg = ERR_PTR(-ENOMEM);
         trace_pnfs_update_layout(ino, pos, count, iomode, lo, NULL,
                      PNFS_UPDATE_LAYOUT_NOMEM);
         nfs_layoutget_end(lo);
         goto out_put_layout_hdr;
     }
 
     lgp->lo = lo;
     pnfs_get_layout_hdr(lo);
 
     lseg = nfs4_proc_layoutget(lgp, &timeout);
     trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                  PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET);
     nfs_layoutget_end(lo);
     if (IS_ERR(lseg)) {
         switch(PTR_ERR(lseg)) {
         case -EBUSY:
             if (time_after(jiffies, giveup))
                 lseg = NULL;
             break;
         case -ERECALLCONFLICT:
         case -EAGAIN:
             break;
         case -ENODATA:
             /* The server returned NFS4ERR_LAYOUTUNAVAILABLE */
             pnfs_layout_set_fail_bit(
                 lo, pnfs_iomode_to_fail_bit(iomode));
             lseg = NULL;
             goto out_put_layout_hdr;
         default:
             if (!nfs_error_is_fatal(PTR_ERR(lseg))) {
                 pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
                 lseg = NULL;
             }
             goto out_put_layout_hdr;
         }
         if (lseg) {
             if (first)
                 pnfs_clear_first_layoutget(lo);
             trace_pnfs_update_layout(ino, pos, count,
                 iomode, lo, lseg, PNFS_UPDATE_LAYOUT_RETRY);
             pnfs_put_layout_hdr(lo);
             goto lookup_again;
         }
     } else {
         pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
     }
 
 out_put_layout_hdr:
     if (first)
         pnfs_clear_first_layoutget(lo);
     trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                  PNFS_UPDATE_LAYOUT_EXIT);
     pnfs_put_layout_hdr(lo);
 out:
     dprintk("%s: inode %s/%llu pNFS layout segment %s for "
             "(%s, offset: %llu, length: %llu)\n",
             __func__, ino->i_sb->s_id,
             (unsigned long long)NFS_FILEID(ino),
             IS_ERR_OR_NULL(lseg) ? "not found" : "found",
             iomode==IOMODE_RW ?  "read/write" : "read-only",
             (unsigned long long)pos,
             (unsigned long long)count);
     return lseg;
 out_unlock:
     spin_unlock(&ino->i_lock);
     goto out_put_layout_hdr;
 }
 EXPORT_SYMBOL_GPL(pnfs_update_layout);
 
 static bool
 pnfs_sanity_check_layout_range(struct pnfs_layout_range *range)
 {
     switch (range->iomode) {
     case IOMODE_READ:
     case IOMODE_RW:
         break;
     default:
         return false;
     }
     if (range->offset == NFS4_MAX_UINT64)
         return false;
     if (range->length == 0)
         return false;
     if (range->length != NFS4_MAX_UINT64 &&
         range->length > NFS4_MAX_UINT64 - range->offset)
         return false;
     return true;
 }
 
 static struct pnfs_layout_hdr *
 _pnfs_grab_empty_layout(struct inode *ino, struct nfs_open_context *ctx)
 {
     struct pnfs_layout_hdr *lo;
 
     spin_lock(&ino->i_lock);
     lo = pnfs_find_alloc_layout(ino, ctx, nfs_io_gfp_mask());
     if (!lo)
         goto out_unlock;
     if (!test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags))
         goto out_unlock;
     if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))
         goto out_unlock;
     if (pnfs_layoutgets_blocked(lo))
         goto out_unlock;
     if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET, &lo->plh_flags))
         goto out_unlock;
     nfs_layoutget_begin(lo);
     spin_unlock(&ino->i_lock);
     _add_to_server_list(lo, NFS_SERVER(ino));
     return lo;
 
 out_unlock:
     spin_unlock(&ino->i_lock);
     pnfs_put_layout_hdr(lo);
     return NULL;
 }
 
 static void _lgopen_prepare_attached(struct nfs4_opendata *data,
                      struct nfs_open_context *ctx)
 {
     struct inode *ino = data->dentry->d_inode;
     struct pnfs_layout_range rng = {
         .iomode = (data->o_arg.fmode & FMODE_WRITE) ?
               IOMODE_RW: IOMODE_READ,
         .offset = 0,
         .length = NFS4_MAX_UINT64,
     };
     struct nfs4_layoutget *lgp;
     struct pnfs_layout_hdr *lo;
 
     /* Heuristic: don't send layoutget if we have cached data */
     if (rng.iomode == IOMODE_READ &&
        (i_size_read(ino) == 0 || ino->i_mapping->nrpages != 0))
         return;
 
     lo = _pnfs_grab_empty_layout(ino, ctx);
     if (!lo)
         return;
     lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid, &rng,
                          nfs_io_gfp_mask());
     if (!lgp) {
         pnfs_clear_first_layoutget(lo);
         nfs_layoutget_end(lo);
         pnfs_put_layout_hdr(lo);
         return;
     }
     lgp->lo = lo;
     data->lgp = lgp;
     data->o_arg.lg_args = &lgp->args;
     data->o_res.lg_res = &lgp->res;
 }
 
 static void _lgopen_prepare_floating(struct nfs4_opendata *data,
                      struct nfs_open_context *ctx)
 {
     struct inode *ino = data->dentry->d_inode;
     struct pnfs_layout_range rng = {
         .iomode = (data->o_arg.fmode & FMODE_WRITE) ?
               IOMODE_RW: IOMODE_READ,
         .offset = 0,
         .length = NFS4_MAX_UINT64,
     };
     struct nfs4_layoutget *lgp;
 
     lgp = pnfs_alloc_init_layoutget_args(ino, ctx, &current_stateid, &rng,
                          nfs_io_gfp_mask());
     if (!lgp)
         return;
     data->lgp = lgp;
     data->o_arg.lg_args = &lgp->args;
     data->o_res.lg_res = &lgp->res;
 }
 
 void pnfs_lgopen_prepare(struct nfs4_opendata *data,
              struct nfs_open_context *ctx)
 {
     struct nfs_server *server = NFS_SERVER(data->dir->d_inode);
 
     if (!(pnfs_enabled_sb(server) &&
           server->pnfs_curr_ld->flags & PNFS_LAYOUTGET_ON_OPEN))
         return;
     /* Could check on max_ops, but currently hardcoded high enough */
     if (!nfs_server_capable(data->dir->d_inode, NFS_CAP_LGOPEN))
         return;
     if (data->lgp)
         return;
     if (data->state)
         _lgopen_prepare_attached(data, ctx);
     else
         _lgopen_prepare_floating(data, ctx);
 }
 
 void pnfs_parse_lgopen(struct inode *ino, struct nfs4_layoutget *lgp,
                struct nfs_open_context *ctx)
 {
     struct pnfs_layout_hdr *lo;
     struct pnfs_layout_segment *lseg;
     struct nfs_server *srv = NFS_SERVER(ino);
     u32 iomode;
 
     if (!lgp)
         return;
     dprintk("%s: entered with status %i\n", __func__, lgp->res.status);
     if (lgp->res.status) {
         switch (lgp->res.status) {
         default:
             break;
         /*
          * Halt lgopen attempts if the server doesn't recognise
          * the "current stateid" value, the layout type, or the
          * layoutget operation as being valid.
          * Also if it complains about too many ops in the compound
          * or of the request/reply being too big.
          */
         case -NFS4ERR_BAD_STATEID:
         case -NFS4ERR_NOTSUPP:
         case -NFS4ERR_REP_TOO_BIG:
         case -NFS4ERR_REP_TOO_BIG_TO_CACHE:
         case -NFS4ERR_REQ_TOO_BIG:
         case -NFS4ERR_TOO_MANY_OPS:
         case -NFS4ERR_UNKNOWN_LAYOUTTYPE:
             srv->caps &= ~NFS_CAP_LGOPEN;
         }
         return;
     }
     if (!lgp->lo) {
         lo = _pnfs_grab_empty_layout(ino, ctx);
         if (!lo)
             return;
         lgp->lo = lo;
     } else
         lo = lgp->lo;
 
     lseg = pnfs_layout_process(lgp);
     if (!IS_ERR(lseg)) {
         iomode = lgp->args.range.iomode;
         pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
         pnfs_put_lseg(lseg);
     }
 }
 
 void nfs4_lgopen_release(struct nfs4_layoutget *lgp)
 {
     if (lgp != NULL) {
         if (lgp->lo) {
             pnfs_clear_first_layoutget(lgp->lo);
             nfs_layoutget_end(lgp->lo);
         }
         pnfs_layoutget_free(lgp);
     }
 }
 
 struct pnfs_layout_segment *
 pnfs_layout_process(struct nfs4_layoutget *lgp)
 {
     struct pnfs_layout_hdr *lo = lgp->lo;
     struct nfs4_layoutget_res *res = &lgp->res;
     struct pnfs_layout_segment *lseg;
     struct inode *ino = lo->plh_inode;
     LIST_HEAD(free_me);
 
     if (!pnfs_sanity_check_layout_range(&res->range))
         return ERR_PTR(-EINVAL);
 
     /* Inject layout blob into I/O device driver */
     lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
     if (IS_ERR_OR_NULL(lseg)) {
         if (!lseg)
             lseg = ERR_PTR(-ENOMEM);
 
         dprintk("%s: Could not allocate layout: error %ld\n",
                __func__, PTR_ERR(lseg));
         return lseg;
     }
 
     pnfs_init_lseg(lo, lseg, &res->range, &res->stateid);
 
     spin_lock(&ino->i_lock);
     if (pnfs_layoutgets_blocked(lo)) {
         dprintk("%s forget reply due to state\n", __func__);
         goto out_forget;
     }
 
     if (test_bit(NFS_LAYOUT_DRAIN, &lo->plh_flags) &&
         !pnfs_is_first_layoutget(lo))
         goto out_forget;
 
     if (nfs4_stateid_match_other(&lo->plh_stateid, &res->stateid)) {
         /* existing state ID, make sure the sequence number matches. */
         if (pnfs_layout_stateid_blocked(lo, &res->stateid)) {
             if (!pnfs_layout_is_valid(lo))
                 lo->plh_barrier = 0;
             dprintk("%s forget reply due to sequence\n", __func__);
             goto out_forget;
         }
         pnfs_set_layout_stateid(lo, &res->stateid, lgp->cred, false);
     } else if (pnfs_layout_is_valid(lo)) {
         /*
          * We got an entirely new state ID.  Mark all segments for the
          * inode invalid, and retry the layoutget
          */
         struct pnfs_layout_range range = {
             .iomode = IOMODE_ANY,
             .length = NFS4_MAX_UINT64,
         };
         pnfs_mark_matching_lsegs_return(lo, &free_me, &range, 0);
         goto out_forget;
     } else {
         /* We have a completely new layout */
         pnfs_set_layout_stateid(lo, &res->stateid, lgp->cred, true);
     }
 
     pnfs_get_lseg(lseg);
     pnfs_layout_insert_lseg(lo, lseg, &free_me);
 
 
     if (res->return_on_close)
         set_bit(NFS_LSEG_ROC, &lseg->pls_flags);
 
     spin_unlock(&ino->i_lock);
     pnfs_free_lseg_list(&free_me);
     return lseg;
 
 out_forget:
     spin_unlock(&ino->i_lock);
     lseg->pls_layout = lo;
     NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
     return ERR_PTR(-EAGAIN);
 }
 
 /**
  * pnfs_mark_matching_lsegs_return - Free or return matching layout segments
  * @lo: pointer to layout header
  * @tmp_list: list header to be used with pnfs_free_lseg_list()
  * @return_range: describe layout segment ranges to be returned
  * @seq: stateid seqid to match
  *
  * This function is mainly intended for use by layoutrecall. It attempts
  * to free the layout segment immediately, or else to mark it for return
  * as soon as its reference count drops to zero.
  *
  * Returns
  * - 0: a layoutreturn needs to be scheduled.
  * - EBUSY: there are layout segment that are still in use.
  * - ENOENT: there are no layout segments that need to be returned.
  */
 int
 pnfs_mark_matching_lsegs_return(struct pnfs_layout_hdr *lo,
                 struct list_head *tmp_list,
                 const struct pnfs_layout_range *return_range,
                 u32 seq)
 {
     struct pnfs_layout_segment *lseg, *next;
     int remaining = 0;
 
     dprintk("%s:Begin lo %p\n", __func__, lo);
 
     assert_spin_locked(&lo->plh_inode->i_lock);
 
     if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
         tmp_list = &lo->plh_return_segs;
 
     list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
         if (pnfs_match_lseg_recall(lseg, return_range, seq)) {
             dprintk("%s: marking lseg %p iomode %d "
                 "offset %llu length %llu\n", __func__,
                 lseg, lseg->pls_range.iomode,
                 lseg->pls_range.offset,
                 lseg->pls_range.length);
             if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
                 tmp_list = &lo->plh_return_segs;
             if (mark_lseg_invalid(lseg, tmp_list))
                 continue;
             remaining++;
             set_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
         }
 
     if (remaining) {
         pnfs_set_plh_return_info(lo, return_range->iomode, seq);
         return -EBUSY;
     }
 
     if (!list_empty(&lo->plh_return_segs)) {
         pnfs_set_plh_return_info(lo, return_range->iomode, seq);
         return 0;
     }
 
     return -ENOENT;
 }
 
 static void
 pnfs_mark_layout_for_return(struct inode *inode,
                 const struct pnfs_layout_range *range)
 {
     struct pnfs_layout_hdr *lo;
     bool return_now = false;
 
     spin_lock(&inode->i_lock);
     lo = NFS_I(inode)->layout;
     if (!pnfs_layout_is_valid(lo)) {
         spin_unlock(&inode->i_lock);
         return;
     }
     pnfs_set_plh_return_info(lo, range->iomode, 0);
     /*
      * mark all matching lsegs so that we are sure to have no live
      * segments at hand when sending layoutreturn. See pnfs_put_lseg()
      * for how it works.
      */
     if (pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs, range, 0) != -EBUSY) {
         const struct cred *cred;
         nfs4_stateid stateid;
         enum pnfs_iomode iomode;
 
         return_now = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
         spin_unlock(&inode->i_lock);
         if (return_now)
             pnfs_send_layoutreturn(lo, &stateid, &cred, iomode, false);
     } else {
         spin_unlock(&inode->i_lock);
         nfs_commit_inode(inode, 0);
     }
 }
 
 void pnfs_error_mark_layout_for_return(struct inode *inode,
                        struct pnfs_layout_segment *lseg)
 {
     struct pnfs_layout_range range = {
         .iomode = lseg->pls_range.iomode,
         .offset = 0,
         .length = NFS4_MAX_UINT64,
     };
 
     pnfs_mark_layout_for_return(inode, &range);
 }
 EXPORT_SYMBOL_GPL(pnfs_error_mark_layout_for_return);
 
 static bool
 pnfs_layout_can_be_returned(struct pnfs_layout_hdr *lo)
 {
     return pnfs_layout_is_valid(lo) &&
         !test_bit(NFS_LAYOUT_INODE_FREEING, &lo->plh_flags) &&
         !test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
 }
 
 static struct pnfs_layout_segment *
 pnfs_find_first_lseg(struct pnfs_layout_hdr *lo,
              const struct pnfs_layout_range *range,
              enum pnfs_iomode iomode)
 {
     struct pnfs_layout_segment *lseg;
 
     list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
         if (!test_bit(NFS_LSEG_VALID, &lseg->pls_flags))
             continue;
         if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
             continue;
         if (lseg->pls_range.iomode != iomode && iomode != IOMODE_ANY)
             continue;
         if (pnfs_lseg_range_intersecting(&lseg->pls_range, range))
             return lseg;
     }
     return NULL;
 }
 
 /* Find open file states whose mode matches that of the range */
 static bool
 pnfs_should_return_unused_layout(struct pnfs_layout_hdr *lo,
                  const struct pnfs_layout_range *range)
 {
     struct list_head *head;
     struct nfs_open_context *ctx;
     fmode_t mode = 0;
 
     if (!pnfs_layout_can_be_returned(lo) ||
         !pnfs_find_first_lseg(lo, range, range->iomode))
         return false;
 
     head = &NFS_I(lo->plh_inode)->open_files;
     list_for_each_entry_rcu(ctx, head, list) {
         if (ctx->state)
             mode |= ctx->state->state & (FMODE_READ|FMODE_WRITE);
     }
 
     switch (range->iomode) {
     default:
         break;
     case IOMODE_READ:
         mode &= ~FMODE_WRITE;
         break;
     case IOMODE_RW:
         if (pnfs_find_first_lseg(lo, range, IOMODE_READ))
             mode &= ~FMODE_READ;
     }
     return mode == 0;
 }
 
 static int
 pnfs_layout_return_unused_byserver(struct nfs_server *server, void *data)
 {
     const struct pnfs_layout_range *range = data;
     struct pnfs_layout_hdr *lo;
     struct inode *inode;
 restart:
     rcu_read_lock();
     list_for_each_entry_rcu(lo, &server->layouts, plh_layouts) {
         if (!pnfs_layout_can_be_returned(lo) ||
             test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
             continue;
         inode = lo->plh_inode;
         spin_lock(&inode->i_lock);
         if (!pnfs_should_return_unused_layout(lo, range)) {
             spin_unlock(&inode->i_lock);
             continue;
         }
         spin_unlock(&inode->i_lock);
         inode = pnfs_grab_inode_layout_hdr(lo);
         if (!inode)
             continue;
         rcu_read_unlock();
         pnfs_mark_layout_for_return(inode, range);
         iput(inode);
         cond_resched();
         goto restart;
     }
     rcu_read_unlock();
     return 0;
 }
 
 void
 pnfs_layout_return_unused_byclid(struct nfs_client *clp,
                  enum pnfs_iomode iomode)
 {
     struct pnfs_layout_range range = {
         .iomode = iomode,
         .offset = 0,
         .length = NFS4_MAX_UINT64,
     };
 
     nfs_client_for_each_server(clp, pnfs_layout_return_unused_byserver,
             &range);
 }
 
 void
 pnfs_generic_pg_check_layout(struct nfs_pageio_descriptor *pgio)
 {
     if (pgio->pg_lseg == NULL ||
         test_bit(NFS_LSEG_VALID, &pgio->pg_lseg->pls_flags))
         return;
     pnfs_put_lseg(pgio->pg_lseg);
     pgio->pg_lseg = NULL;
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_check_layout);
 
 /*
  * Check for any intersection between the request and the pgio->pg_lseg,
  * and if none, put this pgio->pg_lseg away.
  */
 void
 pnfs_generic_pg_check_range(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
 {
     if (pgio->pg_lseg && !pnfs_lseg_request_intersecting(pgio->pg_lseg, req)) {
         pnfs_put_lseg(pgio->pg_lseg);
         pgio->pg_lseg = NULL;
     }
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_check_range);
 
 void
 pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
 {
     u64 rd_size;
 
     pnfs_generic_pg_check_layout(pgio);
     pnfs_generic_pg_check_range(pgio, req);
     if (pgio->pg_lseg == NULL) {
         if (pgio->pg_dreq == NULL)
             rd_size = i_size_read(pgio->pg_inode) - req_offset(req);
         else
             rd_size = nfs_dreq_bytes_left(pgio->pg_dreq);
 
         pgio->pg_lseg =
             pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
                        req_offset(req), rd_size,
                        IOMODE_READ, false,
                        nfs_io_gfp_mask());
         if (IS_ERR(pgio->pg_lseg)) {
             pgio->pg_error = PTR_ERR(pgio->pg_lseg);
             pgio->pg_lseg = NULL;
             return;
         }
     }
     /* If no lseg, fall back to read through mds */
     if (pgio->pg_lseg == NULL)
         nfs_pageio_reset_read_mds(pgio);
 
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_read);
 
 void
 pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
                struct nfs_page *req, u64 wb_size)
 {
     pnfs_generic_pg_check_layout(pgio);
     pnfs_generic_pg_check_range(pgio, req);
     if (pgio->pg_lseg == NULL) {
         pgio->pg_lseg =
             pnfs_update_layout(pgio->pg_inode, nfs_req_openctx(req),
                        req_offset(req), wb_size, IOMODE_RW,
                        false, nfs_io_gfp_mask());
         if (IS_ERR(pgio->pg_lseg)) {
             pgio->pg_error = PTR_ERR(pgio->pg_lseg);
             pgio->pg_lseg = NULL;
             return;
         }
     }
     /* If no lseg, fall back to write through mds */
     if (pgio->pg_lseg == NULL)
         nfs_pageio_reset_write_mds(pgio);
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
 
 void
 pnfs_generic_pg_cleanup(struct nfs_pageio_descriptor *desc)
 {
     if (desc->pg_lseg) {
         pnfs_put_lseg(desc->pg_lseg);
         desc->pg_lseg = NULL;
     }
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_cleanup);
 
 /*
  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
  * of bytes (maximum @req->wb_bytes) that can be coalesced.
  */
 size_t
 pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio,
              struct nfs_page *prev, struct nfs_page *req)
 {
     unsigned int size;
     u64 seg_end, req_start, seg_left;
 
     size = nfs_generic_pg_test(pgio, prev, req);
     if (!size)
         return 0;
 
     /*
      * 'size' contains the number of bytes left in the current page (up
      * to the original size asked for in @req->wb_bytes).
      *
      * Calculate how many bytes are left in the layout segment
      * and if there are less bytes than 'size', return that instead.
      *
      * Please also note that 'end_offset' is actually the offset of the
      * first byte that lies outside the pnfs_layout_range. FIXME?
      *
      */
     if (pgio->pg_lseg) {
         seg_end = pnfs_end_offset(pgio->pg_lseg->pls_range.offset,
                      pgio->pg_lseg->pls_range.length);
         req_start = req_offset(req);
 
         /* start of request is past the last byte of this segment */
         if (req_start >= seg_end)
             return 0;
 
         /* adjust 'size' iff there are fewer bytes left in the
          * segment than what nfs_generic_pg_test returned */
         seg_left = seg_end - req_start;
         if (seg_left < size)
             size = (unsigned int)seg_left;
     }
 
     return size;
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
 
 int pnfs_write_done_resend_to_mds(struct nfs_pgio_header *hdr)
 {
     struct nfs_pageio_descriptor pgio;
 
     /* Resend all requests through the MDS */
     nfs_pageio_init_write(&pgio, hdr->inode, FLUSH_STABLE, true,
                   hdr->completion_ops);
     return nfs_pageio_resend(&pgio, hdr);
 }
 EXPORT_SYMBOL_GPL(pnfs_write_done_resend_to_mds);
 
 static void pnfs_ld_handle_write_error(struct nfs_pgio_header *hdr)
 {
 
     dprintk("pnfs write error = %d\n", hdr->pnfs_error);
     if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
         PNFS_LAYOUTRET_ON_ERROR) {
         pnfs_return_layout(hdr->inode);
     }
     if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
         hdr->task.tk_status = pnfs_write_done_resend_to_mds(hdr);
 }
 
 /*
  * Called by non rpc-based layout drivers
  */
 void pnfs_ld_write_done(struct nfs_pgio_header *hdr)
 {
     if (likely(!hdr->pnfs_error)) {
         pnfs_set_layoutcommit(hdr->inode, hdr->lseg,
                 hdr->mds_offset + hdr->res.count);
         hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
     }
     trace_nfs4_pnfs_write(hdr, hdr->pnfs_error);
     if (unlikely(hdr->pnfs_error))
         pnfs_ld_handle_write_error(hdr);
     hdr->mds_ops->rpc_release(hdr);
 }
 EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
 
 static void
 pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
         struct nfs_pgio_header *hdr)
 {
     struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 
     if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
         list_splice_tail_init(&hdr->pages, &mirror->pg_list);
         nfs_pageio_reset_write_mds(desc);
         mirror->pg_recoalesce = 1;
     }
     hdr->completion_ops->completion(hdr);
 }
 
 static enum pnfs_try_status
 pnfs_try_to_write_data(struct nfs_pgio_header *hdr,
             const struct rpc_call_ops *call_ops,
             struct pnfs_layout_segment *lseg,
             int how)
 {
     struct inode *inode = hdr->inode;
     enum pnfs_try_status trypnfs;
     struct nfs_server *nfss = NFS_SERVER(inode);
 
     hdr->mds_ops = call_ops;
 
     dprintk("%s: Writing ino:%lu %u@%llu (how %d)\n", __func__,
         inode->i_ino, hdr->args.count, hdr->args.offset, how);
     trypnfs = nfss->pnfs_curr_ld->write_pagelist(hdr, how);
     if (trypnfs != PNFS_NOT_ATTEMPTED)
         nfs_inc_stats(inode, NFSIOS_PNFS_WRITE);
     dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
     return trypnfs;
 }
 
 static void
 pnfs_do_write(struct nfs_pageio_descriptor *desc,
           struct nfs_pgio_header *hdr, int how)
 {
     const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
     struct pnfs_layout_segment *lseg = desc->pg_lseg;
     enum pnfs_try_status trypnfs;
 
     trypnfs = pnfs_try_to_write_data(hdr, call_ops, lseg, how);
     switch (trypnfs) {
     case PNFS_NOT_ATTEMPTED:
         pnfs_write_through_mds(desc, hdr);
         break;
     case PNFS_ATTEMPTED:
         break;
     case PNFS_TRY_AGAIN:
         /* cleanup hdr and prepare to redo pnfs */
         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
             struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
             list_splice_init(&hdr->pages, &mirror->pg_list);
             mirror->pg_recoalesce = 1;
         }
         hdr->mds_ops->rpc_release(hdr);
     }
 }
 
 static void pnfs_writehdr_free(struct nfs_pgio_header *hdr)
 {
     pnfs_put_lseg(hdr->lseg);
     nfs_pgio_header_free(hdr);
 }
 
 int
 pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
 {
     struct nfs_pgio_header *hdr;
     int ret;
 
     hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
     if (!hdr) {
         desc->pg_error = -ENOMEM;
         return desc->pg_error;
     }
     nfs_pgheader_init(desc, hdr, pnfs_writehdr_free);
 
     hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
     ret = nfs_generic_pgio(desc, hdr);
     if (!ret)
         pnfs_do_write(desc, hdr, desc->pg_ioflags);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
 
 int pnfs_read_done_resend_to_mds(struct nfs_pgio_header *hdr)
 {
     struct nfs_pageio_descriptor pgio;
 
     /* Resend all requests through the MDS */
     nfs_pageio_init_read(&pgio, hdr->inode, true, hdr->completion_ops);
     return nfs_pageio_resend(&pgio, hdr);
 }
 EXPORT_SYMBOL_GPL(pnfs_read_done_resend_to_mds);
 
 static void pnfs_ld_handle_read_error(struct nfs_pgio_header *hdr)
 {
     dprintk("pnfs read error = %d\n", hdr->pnfs_error);
     if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
         PNFS_LAYOUTRET_ON_ERROR) {
         pnfs_return_layout(hdr->inode);
     }
     if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
         hdr->task.tk_status = pnfs_read_done_resend_to_mds(hdr);
 }
 
 /*
  * Called by non rpc-based layout drivers
  */
 void pnfs_ld_read_done(struct nfs_pgio_header *hdr)
 {
     if (likely(!hdr->pnfs_error))
         hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
     trace_nfs4_pnfs_read(hdr, hdr->pnfs_error);
     if (unlikely(hdr->pnfs_error))
         pnfs_ld_handle_read_error(hdr);
     hdr->mds_ops->rpc_release(hdr);
 }
 EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
 
 static void
 pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
         struct nfs_pgio_header *hdr)
 {
     struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 
     if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
         list_splice_tail_init(&hdr->pages, &mirror->pg_list);
         nfs_pageio_reset_read_mds(desc);
         mirror->pg_recoalesce = 1;
     }
     hdr->completion_ops->completion(hdr);
 }
 
 /*
  * Call the appropriate parallel I/O subsystem read function.
  */
 static enum pnfs_try_status
 pnfs_try_to_read_data(struct nfs_pgio_header *hdr,
                const struct rpc_call_ops *call_ops,
                struct pnfs_layout_segment *lseg)
 {
     struct inode *inode = hdr->inode;
     struct nfs_server *nfss = NFS_SERVER(inode);
     enum pnfs_try_status trypnfs;
 
     hdr->mds_ops = call_ops;
 
     dprintk("%s: Reading ino:%lu %u@%llu\n",
         __func__, inode->i_ino, hdr->args.count, hdr->args.offset);
 
     trypnfs = nfss->pnfs_curr_ld->read_pagelist(hdr);
     if (trypnfs != PNFS_NOT_ATTEMPTED)
         nfs_inc_stats(inode, NFSIOS_PNFS_READ);
     dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
     return trypnfs;
 }
 
 /* Resend all requests through pnfs. */
 void pnfs_read_resend_pnfs(struct nfs_pgio_header *hdr,
                unsigned int mirror_idx)
 {
     struct nfs_pageio_descriptor pgio;
 
     if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
         /* Prevent deadlocks with layoutreturn! */
         pnfs_put_lseg(hdr->lseg);
         hdr->lseg = NULL;
 
         nfs_pageio_init_read(&pgio, hdr->inode, false,
                     hdr->completion_ops);
         pgio.pg_mirror_idx = mirror_idx;
         hdr->task.tk_status = nfs_pageio_resend(&pgio, hdr);
     }
 }
 EXPORT_SYMBOL_GPL(pnfs_read_resend_pnfs);
 
 static void
 pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
 {
     const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
     struct pnfs_layout_segment *lseg = desc->pg_lseg;
     enum pnfs_try_status trypnfs;
 
     trypnfs = pnfs_try_to_read_data(hdr, call_ops, lseg);
     switch (trypnfs) {
     case PNFS_NOT_ATTEMPTED:
         pnfs_read_through_mds(desc, hdr);
         break;
     case PNFS_ATTEMPTED:
         break;
     case PNFS_TRY_AGAIN:
         /* cleanup hdr and prepare to redo pnfs */
         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
             struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
             list_splice_init(&hdr->pages, &mirror->pg_list);
             mirror->pg_recoalesce = 1;
         }
         hdr->mds_ops->rpc_release(hdr);
     }
 }
 
 static void pnfs_readhdr_free(struct nfs_pgio_header *hdr)
 {
     pnfs_put_lseg(hdr->lseg);
     nfs_pgio_header_free(hdr);
 }
 
 int
 pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
 {
     struct nfs_pgio_header *hdr;
     int ret;
 
     hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
     if (!hdr) {
         desc->pg_error = -ENOMEM;
         return desc->pg_error;
     }
     nfs_pgheader_init(desc, hdr, pnfs_readhdr_free);
     hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
     ret = nfs_generic_pgio(desc, hdr);
     if (!ret)
         pnfs_do_read(desc, hdr);
     return ret;
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
 
 static void pnfs_clear_layoutcommitting(struct inode *inode)
 {
     unsigned long *bitlock = &NFS_I(inode)->flags;
 
     clear_bit_unlock(NFS_INO_LAYOUTCOMMITTING, bitlock);
     smp_mb__after_atomic();
     wake_up_bit(bitlock, NFS_INO_LAYOUTCOMMITTING);
 }
 
 /*
  * There can be multiple RW segments.
  */
 static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp)
 {
     struct pnfs_layout_segment *lseg;
 
     list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
         if (lseg->pls_range.iomode == IOMODE_RW &&
             test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
             list_add(&lseg->pls_lc_list, listp);
     }
 }
 
 static void pnfs_list_write_lseg_done(struct inode *inode, struct list_head *listp)
 {
     struct pnfs_layout_segment *lseg, *tmp;
 
     /* Matched by references in pnfs_set_layoutcommit */
     list_for_each_entry_safe(lseg, tmp, listp, pls_lc_list) {
         list_del_init(&lseg->pls_lc_list);
         pnfs_put_lseg(lseg);
     }
 
     pnfs_clear_layoutcommitting(inode);
 }
 
 void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg)
 {
     pnfs_layout_io_set_failed(lseg->pls_layout, lseg->pls_range.iomode);
 }
 EXPORT_SYMBOL_GPL(pnfs_set_lo_fail);
 
 void
 pnfs_set_layoutcommit(struct inode *inode, struct pnfs_layout_segment *lseg,
         loff_t end_pos)
 {
     struct nfs_inode *nfsi = NFS_I(inode);
     bool mark_as_dirty = false;
 
     spin_lock(&inode->i_lock);
     if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
         nfsi->layout->plh_lwb = end_pos;
         mark_as_dirty = true;
         dprintk("%s: Set layoutcommit for inode %lu ",
             __func__, inode->i_ino);
     } else if (end_pos > nfsi->layout->plh_lwb)
         nfsi->layout->plh_lwb = end_pos;
     if (!test_and_set_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags)) {
         /* references matched in nfs4_layoutcommit_release */
         pnfs_get_lseg(lseg);
     }
     spin_unlock(&inode->i_lock);
     dprintk("%s: lseg %p end_pos %llu\n",
         __func__, lseg, nfsi->layout->plh_lwb);
 
     /* if pnfs_layoutcommit_inode() runs between inode locks, the next one
      * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
     if (mark_as_dirty)
         mark_inode_dirty_sync(inode);
 }
 EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);
 
 void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data)
 {
     struct nfs_server *nfss = NFS_SERVER(data->args.inode);
 
     if (nfss->pnfs_curr_ld->cleanup_layoutcommit)
         nfss->pnfs_curr_ld->cleanup_layoutcommit(data);
     pnfs_list_write_lseg_done(data->args.inode, &data->lseg_list);
 }
 
 /*
  * For the LAYOUT4_NFSV4_1_FILES layout type, NFS_DATA_SYNC WRITEs and
  * NFS_UNSTABLE WRITEs with a COMMIT to data servers must store enough
  * data to disk to allow the server to recover the data if it crashes.
  * LAYOUTCOMMIT is only needed when the NFL4_UFLG_COMMIT_THRU_MDS flag
  * is off, and a COMMIT is sent to a data server, or
  * if WRITEs to a data server return NFS_DATA_SYNC.
  */
 int
 pnfs_layoutcommit_inode(struct inode *inode, bool sync)
 {
     struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
     struct nfs4_layoutcommit_data *data;
     struct nfs_inode *nfsi = NFS_I(inode);
     loff_t end_pos;
     int status;
 
     if (!pnfs_layoutcommit_outstanding(inode))
         return 0;
 
     dprintk("--> %s inode %lu\n", __func__, inode->i_ino);
 
     status = -EAGAIN;
     if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
         if (!sync)
             goto out;
         status = wait_on_bit_lock_action(&nfsi->flags,
                 NFS_INO_LAYOUTCOMMITTING,
                 nfs_wait_bit_killable,
                 TASK_KILLABLE);
         if (status)
             goto out;
     }
 
     status = -ENOMEM;
     /* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
     data = kzalloc(sizeof(*data), nfs_io_gfp_mask());
     if (!data)
         goto clear_layoutcommitting;
 
     status = 0;
     spin_lock(&inode->i_lock);
     if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
         goto out_unlock;
 
     INIT_LIST_HEAD(&data->lseg_list);
     pnfs_list_write_lseg(inode, &data->lseg_list);
 
     end_pos = nfsi->layout->plh_lwb;
 
     nfs4_stateid_copy(&data->args.stateid, &nfsi->layout->plh_stateid);
     data->cred = get_cred(nfsi->layout->plh_lc_cred);
     spin_unlock(&inode->i_lock);
 
     data->args.inode = inode;
     nfs_fattr_init(&data->fattr);
     data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
     data->res.fattr = &data->fattr;
     if (end_pos != 0)
         data->args.lastbytewritten = end_pos - 1;
     else
         data->args.lastbytewritten = U64_MAX;
     data->res.server = NFS_SERVER(inode);
 
     if (ld->prepare_layoutcommit) {
         status = ld->prepare_layoutcommit(&data->args);
         if (status) {
             put_cred(data->cred);
             spin_lock(&inode->i_lock);
             set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags);
             if (end_pos > nfsi->layout->plh_lwb)
                 nfsi->layout->plh_lwb = end_pos;
             goto out_unlock;
         }
     }
 
 
     status = nfs4_proc_layoutcommit(data, sync);
 out:
     if (status)
         mark_inode_dirty_sync(inode);
     dprintk("<-- %s status %d\n", __func__, status);
     return status;
 out_unlock:
     spin_unlock(&inode->i_lock);
     kfree(data);
 clear_layoutcommitting:
     pnfs_clear_layoutcommitting(inode);
     goto out;
 }
 EXPORT_SYMBOL_GPL(pnfs_layoutcommit_inode);
 
 int
 pnfs_generic_sync(struct inode *inode, bool datasync)
 {
     return pnfs_layoutcommit_inode(inode, true);
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_sync);
 
 struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
 {
     struct nfs4_threshold *thp;
 
     thp = kzalloc(sizeof(*thp), nfs_io_gfp_mask());
     if (!thp) {
         dprintk("%s mdsthreshold allocation failed\n", __func__);
         return NULL;
     }
     return thp;
 }
 
 #if IS_ENABLED(CONFIG_NFS_V4_2)
 int
 pnfs_report_layoutstat(struct inode *inode, gfp_t gfp_flags)
 {
     struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
     struct nfs_server *server = NFS_SERVER(inode);
     struct nfs_inode *nfsi = NFS_I(inode);
     struct nfs42_layoutstat_data *data;
     struct pnfs_layout_hdr *hdr;
     int status = 0;
 
     if (!pnfs_enabled_sb(server) || !ld->prepare_layoutstats)
         goto out;
 
     if (!nfs_server_capable(inode, NFS_CAP_LAYOUTSTATS))
         goto out;
 
     if (test_and_set_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags))
         goto out;
 
     spin_lock(&inode->i_lock);
     if (!NFS_I(inode)->layout) {
         spin_unlock(&inode->i_lock);
         goto out_clear_layoutstats;
     }
     hdr = NFS_I(inode)->layout;
     pnfs_get_layout_hdr(hdr);
     spin_unlock(&inode->i_lock);
 
     data = kzalloc(sizeof(*data), gfp_flags);
     if (!data) {
         status = -ENOMEM;
         goto out_put;
     }
 
     data->args.fh = NFS_FH(inode);
     data->args.inode = inode;
     status = ld->prepare_layoutstats(&data->args);
     if (status)
         goto out_free;
 
     status = nfs42_proc_layoutstats_generic(NFS_SERVER(inode), data);
 
 out:
     dprintk("%s returns %d\n", __func__, status);
     return status;
 
 out_free:
     kfree(data);
 out_put:
     pnfs_put_layout_hdr(hdr);
 out_clear_layoutstats:
     smp_mb__before_atomic();
     clear_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags);
     smp_mb__after_atomic();
     goto out;
 }
 EXPORT_SYMBOL_GPL(pnfs_report_layoutstat);
 #endif
 
 unsigned int layoutstats_timer;
 module_param(layoutstats_timer, uint, 0644);
 EXPORT_SYMBOL_GPL(layoutstats_timer);