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TOMOYO Linux Cross Reference
Linux/fs/nfs/pnfs.c

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  1 /*
  2  *  pNFS functions to call and manage layout drivers.
  3  *
  4  *  Copyright (c) 2002 [year of first publication]
  5  *  The Regents of the University of Michigan
  6  *  All Rights Reserved
  7  *
  8  *  Dean Hildebrand <dhildebz@umich.edu>
  9  *
 10  *  Permission is granted to use, copy, create derivative works, and
 11  *  redistribute this software and such derivative works for any purpose,
 12  *  so long as the name of the University of Michigan is not used in
 13  *  any advertising or publicity pertaining to the use or distribution
 14  *  of this software without specific, written prior authorization. If
 15  *  the above copyright notice or any other identification of the
 16  *  University of Michigan is included in any copy of any portion of
 17  *  this software, then the disclaimer below must also be included.
 18  *
 19  *  This software is provided as is, without representation or warranty
 20  *  of any kind either express or implied, including without limitation
 21  *  the implied warranties of merchantability, fitness for a particular
 22  *  purpose, or noninfringement.  The Regents of the University of
 23  *  Michigan shall not be liable for any damages, including special,
 24  *  indirect, incidental, or consequential damages, with respect to any
 25  *  claim arising out of or in connection with the use of the software,
 26  *  even if it has been or is hereafter advised of the possibility of
 27  *  such damages.
 28  */
 29 
 30 #include <linux/nfs_fs.h>
 31 #include <linux/nfs_page.h>
 32 #include <linux/module.h>
 33 #include "internal.h"
 34 #include "pnfs.h"
 35 #include "iostat.h"
 36 #include "nfs4trace.h"
 37 #include "delegation.h"
 38 #include "nfs42.h"
 39 
 40 #define NFSDBG_FACILITY         NFSDBG_PNFS
 41 #define PNFS_LAYOUTGET_RETRY_TIMEOUT (120*HZ)
 42 
 43 /* Locking:
 44  *
 45  * pnfs_spinlock:
 46  *      protects pnfs_modules_tbl.
 47  */
 48 static DEFINE_SPINLOCK(pnfs_spinlock);
 49 
 50 /*
 51  * pnfs_modules_tbl holds all pnfs modules
 52  */
 53 static LIST_HEAD(pnfs_modules_tbl);
 54 
 55 static void pnfs_layoutreturn_before_put_layout_hdr(struct pnfs_layout_hdr *lo);
 56 
 57 /* Return the registered pnfs layout driver module matching given id */
 58 static struct pnfs_layoutdriver_type *
 59 find_pnfs_driver_locked(u32 id)
 60 {
 61         struct pnfs_layoutdriver_type *local;
 62 
 63         list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid)
 64                 if (local->id == id)
 65                         goto out;
 66         local = NULL;
 67 out:
 68         dprintk("%s: Searching for id %u, found %p\n", __func__, id, local);
 69         return local;
 70 }
 71 
 72 static struct pnfs_layoutdriver_type *
 73 find_pnfs_driver(u32 id)
 74 {
 75         struct pnfs_layoutdriver_type *local;
 76 
 77         spin_lock(&pnfs_spinlock);
 78         local = find_pnfs_driver_locked(id);
 79         if (local != NULL && !try_module_get(local->owner)) {
 80                 dprintk("%s: Could not grab reference on module\n", __func__);
 81                 local = NULL;
 82         }
 83         spin_unlock(&pnfs_spinlock);
 84         return local;
 85 }
 86 
 87 void
 88 unset_pnfs_layoutdriver(struct nfs_server *nfss)
 89 {
 90         if (nfss->pnfs_curr_ld) {
 91                 if (nfss->pnfs_curr_ld->clear_layoutdriver)
 92                         nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
 93                 /* Decrement the MDS count. Purge the deviceid cache if zero */
 94                 if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count))
 95                         nfs4_deviceid_purge_client(nfss->nfs_client);
 96                 module_put(nfss->pnfs_curr_ld->owner);
 97         }
 98         nfss->pnfs_curr_ld = NULL;
 99 }
100 
101 /*
102  * Try to set the server's pnfs module to the pnfs layout type specified by id.
103  * Currently only one pNFS layout driver per filesystem is supported.
104  *
105  * @id layout type. Zero (illegal layout type) indicates pNFS not in use.
106  */
107 void
108 set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
109                       u32 id)
110 {
111         struct pnfs_layoutdriver_type *ld_type = NULL;
112 
113         if (id == 0)
114                 goto out_no_driver;
115         if (!(server->nfs_client->cl_exchange_flags &
116                  (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) {
117                 printk(KERN_ERR "NFS: %s: id %u cl_exchange_flags 0x%x\n",
118                         __func__, id, server->nfs_client->cl_exchange_flags);
119                 goto out_no_driver;
120         }
121         ld_type = find_pnfs_driver(id);
122         if (!ld_type) {
123                 request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX, id);
124                 ld_type = find_pnfs_driver(id);
125                 if (!ld_type) {
126                         dprintk("%s: No pNFS module found for %u.\n",
127                                 __func__, id);
128                         goto out_no_driver;
129                 }
130         }
131         server->pnfs_curr_ld = ld_type;
132         if (ld_type->set_layoutdriver
133             && ld_type->set_layoutdriver(server, mntfh)) {
134                 printk(KERN_ERR "NFS: %s: Error initializing pNFS layout "
135                         "driver %u.\n", __func__, id);
136                 module_put(ld_type->owner);
137                 goto out_no_driver;
138         }
139         /* Bump the MDS count */
140         atomic_inc(&server->nfs_client->cl_mds_count);
141 
142         dprintk("%s: pNFS module for %u set\n", __func__, id);
143         return;
144 
145 out_no_driver:
146         dprintk("%s: Using NFSv4 I/O\n", __func__);
147         server->pnfs_curr_ld = NULL;
148 }
149 
150 int
151 pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
152 {
153         int status = -EINVAL;
154         struct pnfs_layoutdriver_type *tmp;
155 
156         if (ld_type->id == 0) {
157                 printk(KERN_ERR "NFS: %s id 0 is reserved\n", __func__);
158                 return status;
159         }
160         if (!ld_type->alloc_lseg || !ld_type->free_lseg) {
161                 printk(KERN_ERR "NFS: %s Layout driver must provide "
162                        "alloc_lseg and free_lseg.\n", __func__);
163                 return status;
164         }
165 
166         spin_lock(&pnfs_spinlock);
167         tmp = find_pnfs_driver_locked(ld_type->id);
168         if (!tmp) {
169                 list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl);
170                 status = 0;
171                 dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id,
172                         ld_type->name);
173         } else {
174                 printk(KERN_ERR "NFS: %s Module with id %d already loaded!\n",
175                         __func__, ld_type->id);
176         }
177         spin_unlock(&pnfs_spinlock);
178 
179         return status;
180 }
181 EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver);
182 
183 void
184 pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
185 {
186         dprintk("%s Deregistering id:%u\n", __func__, ld_type->id);
187         spin_lock(&pnfs_spinlock);
188         list_del(&ld_type->pnfs_tblid);
189         spin_unlock(&pnfs_spinlock);
190 }
191 EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
192 
193 /*
194  * pNFS client layout cache
195  */
196 
197 /* Need to hold i_lock if caller does not already hold reference */
198 void
199 pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo)
200 {
201         atomic_inc(&lo->plh_refcount);
202 }
203 
204 static struct pnfs_layout_hdr *
205 pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
206 {
207         struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
208         return ld->alloc_layout_hdr(ino, gfp_flags);
209 }
210 
211 static void
212 pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
213 {
214         struct nfs_server *server = NFS_SERVER(lo->plh_inode);
215         struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
216 
217         if (!list_empty(&lo->plh_layouts)) {
218                 struct nfs_client *clp = server->nfs_client;
219 
220                 spin_lock(&clp->cl_lock);
221                 list_del_init(&lo->plh_layouts);
222                 spin_unlock(&clp->cl_lock);
223         }
224         put_rpccred(lo->plh_lc_cred);
225         return ld->free_layout_hdr(lo);
226 }
227 
228 static void
229 pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
230 {
231         struct nfs_inode *nfsi = NFS_I(lo->plh_inode);
232         dprintk("%s: freeing layout cache %p\n", __func__, lo);
233         nfsi->layout = NULL;
234         /* Reset MDS Threshold I/O counters */
235         nfsi->write_io = 0;
236         nfsi->read_io = 0;
237 }
238 
239 void
240 pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
241 {
242         struct inode *inode = lo->plh_inode;
243 
244         pnfs_layoutreturn_before_put_layout_hdr(lo);
245 
246         if (atomic_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
247                 if (!list_empty(&lo->plh_segs))
248                         WARN_ONCE(1, "NFS: BUG unfreed layout segments.\n");
249                 pnfs_detach_layout_hdr(lo);
250                 spin_unlock(&inode->i_lock);
251                 pnfs_free_layout_hdr(lo);
252         }
253 }
254 
255 /*
256  * Mark a pnfs_layout_hdr and all associated layout segments as invalid
257  *
258  * In order to continue using the pnfs_layout_hdr, a full recovery
259  * is required.
260  * Note that caller must hold inode->i_lock.
261  */
262 static int
263 pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
264                 struct list_head *lseg_list)
265 {
266         struct pnfs_layout_range range = {
267                 .iomode = IOMODE_ANY,
268                 .offset = 0,
269                 .length = NFS4_MAX_UINT64,
270         };
271 
272         set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
273         return pnfs_mark_matching_lsegs_invalid(lo, lseg_list, &range);
274 }
275 
276 static int
277 pnfs_iomode_to_fail_bit(u32 iomode)
278 {
279         return iomode == IOMODE_RW ?
280                 NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;
281 }
282 
283 static void
284 pnfs_layout_set_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
285 {
286         lo->plh_retry_timestamp = jiffies;
287         if (!test_and_set_bit(fail_bit, &lo->plh_flags))
288                 atomic_inc(&lo->plh_refcount);
289 }
290 
291 static void
292 pnfs_layout_clear_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
293 {
294         if (test_and_clear_bit(fail_bit, &lo->plh_flags))
295                 atomic_dec(&lo->plh_refcount);
296 }
297 
298 static void
299 pnfs_layout_io_set_failed(struct pnfs_layout_hdr *lo, u32 iomode)
300 {
301         struct inode *inode = lo->plh_inode;
302         struct pnfs_layout_range range = {
303                 .iomode = iomode,
304                 .offset = 0,
305                 .length = NFS4_MAX_UINT64,
306         };
307         LIST_HEAD(head);
308 
309         spin_lock(&inode->i_lock);
310         pnfs_layout_set_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
311         pnfs_mark_matching_lsegs_invalid(lo, &head, &range);
312         spin_unlock(&inode->i_lock);
313         pnfs_free_lseg_list(&head);
314         dprintk("%s Setting layout IOMODE_%s fail bit\n", __func__,
315                         iomode == IOMODE_RW ?  "RW" : "READ");
316 }
317 
318 static bool
319 pnfs_layout_io_test_failed(struct pnfs_layout_hdr *lo, u32 iomode)
320 {
321         unsigned long start, end;
322         int fail_bit = pnfs_iomode_to_fail_bit(iomode);
323 
324         if (test_bit(fail_bit, &lo->plh_flags) == 0)
325                 return false;
326         end = jiffies;
327         start = end - PNFS_LAYOUTGET_RETRY_TIMEOUT;
328         if (!time_in_range(lo->plh_retry_timestamp, start, end)) {
329                 /* It is time to retry the failed layoutgets */
330                 pnfs_layout_clear_fail_bit(lo, fail_bit);
331                 return false;
332         }
333         return true;
334 }
335 
336 static void
337 init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg)
338 {
339         INIT_LIST_HEAD(&lseg->pls_list);
340         INIT_LIST_HEAD(&lseg->pls_lc_list);
341         atomic_set(&lseg->pls_refcount, 1);
342         smp_mb();
343         set_bit(NFS_LSEG_VALID, &lseg->pls_flags);
344         lseg->pls_layout = lo;
345 }
346 
347 static void pnfs_free_lseg(struct pnfs_layout_segment *lseg)
348 {
349         struct inode *ino = lseg->pls_layout->plh_inode;
350 
351         NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
352 }
353 
354 static void
355 pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
356                 struct pnfs_layout_segment *lseg)
357 {
358         struct inode *inode = lo->plh_inode;
359 
360         WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
361         list_del_init(&lseg->pls_list);
362         /* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
363         atomic_dec(&lo->plh_refcount);
364         if (list_empty(&lo->plh_segs))
365                 clear_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
366         rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
367 }
368 
369 void
370 pnfs_put_lseg(struct pnfs_layout_segment *lseg)
371 {
372         struct pnfs_layout_hdr *lo;
373         struct inode *inode;
374 
375         if (!lseg)
376                 return;
377 
378         dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
379                 atomic_read(&lseg->pls_refcount),
380                 test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
381 
382         lo = lseg->pls_layout;
383         inode = lo->plh_inode;
384 
385         if (atomic_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
386                 if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
387                         spin_unlock(&inode->i_lock);
388                         return;
389                 }
390                 pnfs_get_layout_hdr(lo);
391                 pnfs_layout_remove_lseg(lo, lseg);
392                 spin_unlock(&inode->i_lock);
393                 pnfs_free_lseg(lseg);
394                 pnfs_put_layout_hdr(lo);
395         }
396 }
397 EXPORT_SYMBOL_GPL(pnfs_put_lseg);
398 
399 static void pnfs_free_lseg_async_work(struct work_struct *work)
400 {
401         struct pnfs_layout_segment *lseg;
402         struct pnfs_layout_hdr *lo;
403 
404         lseg = container_of(work, struct pnfs_layout_segment, pls_work);
405         lo = lseg->pls_layout;
406 
407         pnfs_free_lseg(lseg);
408         pnfs_put_layout_hdr(lo);
409 }
410 
411 static void pnfs_free_lseg_async(struct pnfs_layout_segment *lseg)
412 {
413         INIT_WORK(&lseg->pls_work, pnfs_free_lseg_async_work);
414         schedule_work(&lseg->pls_work);
415 }
416 
417 void
418 pnfs_put_lseg_locked(struct pnfs_layout_segment *lseg)
419 {
420         if (!lseg)
421                 return;
422 
423         assert_spin_locked(&lseg->pls_layout->plh_inode->i_lock);
424 
425         dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
426                 atomic_read(&lseg->pls_refcount),
427                 test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
428         if (atomic_dec_and_test(&lseg->pls_refcount)) {
429                 struct pnfs_layout_hdr *lo = lseg->pls_layout;
430                 if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags))
431                         return;
432                 pnfs_get_layout_hdr(lo);
433                 pnfs_layout_remove_lseg(lo, lseg);
434                 pnfs_free_lseg_async(lseg);
435         }
436 }
437 EXPORT_SYMBOL_GPL(pnfs_put_lseg_locked);
438 
439 static u64
440 end_offset(u64 start, u64 len)
441 {
442         u64 end;
443 
444         end = start + len;
445         return end >= start ? end : NFS4_MAX_UINT64;
446 }
447 
448 /*
449  * is l2 fully contained in l1?
450  *   start1                             end1
451  *   [----------------------------------)
452  *           start2           end2
453  *           [----------------)
454  */
455 static bool
456 pnfs_lseg_range_contained(const struct pnfs_layout_range *l1,
457                  const struct pnfs_layout_range *l2)
458 {
459         u64 start1 = l1->offset;
460         u64 end1 = end_offset(start1, l1->length);
461         u64 start2 = l2->offset;
462         u64 end2 = end_offset(start2, l2->length);
463 
464         return (start1 <= start2) && (end1 >= end2);
465 }
466 
467 /*
468  * is l1 and l2 intersecting?
469  *   start1                             end1
470  *   [----------------------------------)
471  *                              start2           end2
472  *                              [----------------)
473  */
474 static bool
475 pnfs_lseg_range_intersecting(const struct pnfs_layout_range *l1,
476                     const struct pnfs_layout_range *l2)
477 {
478         u64 start1 = l1->offset;
479         u64 end1 = end_offset(start1, l1->length);
480         u64 start2 = l2->offset;
481         u64 end2 = end_offset(start2, l2->length);
482 
483         return (end1 == NFS4_MAX_UINT64 || end1 > start2) &&
484                (end2 == NFS4_MAX_UINT64 || end2 > start1);
485 }
486 
487 static bool
488 should_free_lseg(const struct pnfs_layout_range *lseg_range,
489                  const struct pnfs_layout_range *recall_range)
490 {
491         return (recall_range->iomode == IOMODE_ANY ||
492                 lseg_range->iomode == recall_range->iomode) &&
493                pnfs_lseg_range_intersecting(lseg_range, recall_range);
494 }
495 
496 static bool pnfs_lseg_dec_and_remove_zero(struct pnfs_layout_segment *lseg,
497                 struct list_head *tmp_list)
498 {
499         if (!atomic_dec_and_test(&lseg->pls_refcount))
500                 return false;
501         pnfs_layout_remove_lseg(lseg->pls_layout, lseg);
502         list_add(&lseg->pls_list, tmp_list);
503         return true;
504 }
505 
506 /* Returns 1 if lseg is removed from list, 0 otherwise */
507 static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
508                              struct list_head *tmp_list)
509 {
510         int rv = 0;
511 
512         if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
513                 /* Remove the reference keeping the lseg in the
514                  * list.  It will now be removed when all
515                  * outstanding io is finished.
516                  */
517                 dprintk("%s: lseg %p ref %d\n", __func__, lseg,
518                         atomic_read(&lseg->pls_refcount));
519                 if (pnfs_lseg_dec_and_remove_zero(lseg, tmp_list))
520                         rv = 1;
521         }
522         return rv;
523 }
524 
525 /* Returns count of number of matching invalid lsegs remaining in list
526  * after call.
527  */
528 int
529 pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
530                             struct list_head *tmp_list,
531                             const struct pnfs_layout_range *recall_range)
532 {
533         struct pnfs_layout_segment *lseg, *next;
534         int remaining = 0;
535 
536         dprintk("%s:Begin lo %p\n", __func__, lo);
537 
538         if (list_empty(&lo->plh_segs))
539                 return 0;
540         list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
541                 if (!recall_range ||
542                     should_free_lseg(&lseg->pls_range, recall_range)) {
543                         dprintk("%s: freeing lseg %p iomode %d "
544                                 "offset %llu length %llu\n", __func__,
545                                 lseg, lseg->pls_range.iomode, lseg->pls_range.offset,
546                                 lseg->pls_range.length);
547                         if (!mark_lseg_invalid(lseg, tmp_list))
548                                 remaining++;
549                 }
550         dprintk("%s:Return %i\n", __func__, remaining);
551         return remaining;
552 }
553 
554 /* note free_me must contain lsegs from a single layout_hdr */
555 void
556 pnfs_free_lseg_list(struct list_head *free_me)
557 {
558         struct pnfs_layout_segment *lseg, *tmp;
559 
560         if (list_empty(free_me))
561                 return;
562 
563         list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
564                 list_del(&lseg->pls_list);
565                 pnfs_free_lseg(lseg);
566         }
567 }
568 
569 void
570 pnfs_destroy_layout(struct nfs_inode *nfsi)
571 {
572         struct pnfs_layout_hdr *lo;
573         LIST_HEAD(tmp_list);
574 
575         spin_lock(&nfsi->vfs_inode.i_lock);
576         lo = nfsi->layout;
577         if (lo) {
578                 pnfs_get_layout_hdr(lo);
579                 pnfs_mark_layout_stateid_invalid(lo, &tmp_list);
580                 pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
581                 pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
582                 spin_unlock(&nfsi->vfs_inode.i_lock);
583                 pnfs_free_lseg_list(&tmp_list);
584                 pnfs_put_layout_hdr(lo);
585         } else
586                 spin_unlock(&nfsi->vfs_inode.i_lock);
587 }
588 EXPORT_SYMBOL_GPL(pnfs_destroy_layout);
589 
590 static bool
591 pnfs_layout_add_bulk_destroy_list(struct inode *inode,
592                 struct list_head *layout_list)
593 {
594         struct pnfs_layout_hdr *lo;
595         bool ret = false;
596 
597         spin_lock(&inode->i_lock);
598         lo = NFS_I(inode)->layout;
599         if (lo != NULL && list_empty(&lo->plh_bulk_destroy)) {
600                 pnfs_get_layout_hdr(lo);
601                 list_add(&lo->plh_bulk_destroy, layout_list);
602                 ret = true;
603         }
604         spin_unlock(&inode->i_lock);
605         return ret;
606 }
607 
608 /* Caller must hold rcu_read_lock and clp->cl_lock */
609 static int
610 pnfs_layout_bulk_destroy_byserver_locked(struct nfs_client *clp,
611                 struct nfs_server *server,
612                 struct list_head *layout_list)
613 {
614         struct pnfs_layout_hdr *lo, *next;
615         struct inode *inode;
616 
617         list_for_each_entry_safe(lo, next, &server->layouts, plh_layouts) {
618                 inode = igrab(lo->plh_inode);
619                 if (inode == NULL)
620                         continue;
621                 list_del_init(&lo->plh_layouts);
622                 if (pnfs_layout_add_bulk_destroy_list(inode, layout_list))
623                         continue;
624                 rcu_read_unlock();
625                 spin_unlock(&clp->cl_lock);
626                 iput(inode);
627                 spin_lock(&clp->cl_lock);
628                 rcu_read_lock();
629                 return -EAGAIN;
630         }
631         return 0;
632 }
633 
634 static int
635 pnfs_layout_free_bulk_destroy_list(struct list_head *layout_list,
636                 bool is_bulk_recall)
637 {
638         struct pnfs_layout_hdr *lo;
639         struct inode *inode;
640         LIST_HEAD(lseg_list);
641         int ret = 0;
642 
643         while (!list_empty(layout_list)) {
644                 lo = list_entry(layout_list->next, struct pnfs_layout_hdr,
645                                 plh_bulk_destroy);
646                 dprintk("%s freeing layout for inode %lu\n", __func__,
647                         lo->plh_inode->i_ino);
648                 inode = lo->plh_inode;
649 
650                 pnfs_layoutcommit_inode(inode, false);
651 
652                 spin_lock(&inode->i_lock);
653                 list_del_init(&lo->plh_bulk_destroy);
654                 if (pnfs_mark_layout_stateid_invalid(lo, &lseg_list)) {
655                         if (is_bulk_recall)
656                                 set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
657                         ret = -EAGAIN;
658                 }
659                 spin_unlock(&inode->i_lock);
660                 pnfs_free_lseg_list(&lseg_list);
661                 /* Free all lsegs that are attached to commit buckets */
662                 nfs_commit_inode(inode, 0);
663                 pnfs_put_layout_hdr(lo);
664                 iput(inode);
665         }
666         return ret;
667 }
668 
669 int
670 pnfs_destroy_layouts_byfsid(struct nfs_client *clp,
671                 struct nfs_fsid *fsid,
672                 bool is_recall)
673 {
674         struct nfs_server *server;
675         LIST_HEAD(layout_list);
676 
677         spin_lock(&clp->cl_lock);
678         rcu_read_lock();
679 restart:
680         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
681                 if (memcmp(&server->fsid, fsid, sizeof(*fsid)) != 0)
682                         continue;
683                 if (pnfs_layout_bulk_destroy_byserver_locked(clp,
684                                 server,
685                                 &layout_list) != 0)
686                         goto restart;
687         }
688         rcu_read_unlock();
689         spin_unlock(&clp->cl_lock);
690 
691         if (list_empty(&layout_list))
692                 return 0;
693         return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
694 }
695 
696 int
697 pnfs_destroy_layouts_byclid(struct nfs_client *clp,
698                 bool is_recall)
699 {
700         struct nfs_server *server;
701         LIST_HEAD(layout_list);
702 
703         spin_lock(&clp->cl_lock);
704         rcu_read_lock();
705 restart:
706         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
707                 if (pnfs_layout_bulk_destroy_byserver_locked(clp,
708                                         server,
709                                         &layout_list) != 0)
710                         goto restart;
711         }
712         rcu_read_unlock();
713         spin_unlock(&clp->cl_lock);
714 
715         if (list_empty(&layout_list))
716                 return 0;
717         return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
718 }
719 
720 /*
721  * Called by the state manger to remove all layouts established under an
722  * expired lease.
723  */
724 void
725 pnfs_destroy_all_layouts(struct nfs_client *clp)
726 {
727         nfs4_deviceid_mark_client_invalid(clp);
728         nfs4_deviceid_purge_client(clp);
729 
730         pnfs_destroy_layouts_byclid(clp, false);
731 }
732 
733 /*
734  * Compare 2 layout stateid sequence ids, to see which is newer,
735  * taking into account wraparound issues.
736  */
737 static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
738 {
739         return (s32)(s1 - s2) > 0;
740 }
741 
742 /* update lo->plh_stateid with new if is more recent */
743 void
744 pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
745                         bool update_barrier)
746 {
747         u32 oldseq, newseq, new_barrier;
748         int empty = list_empty(&lo->plh_segs);
749 
750         oldseq = be32_to_cpu(lo->plh_stateid.seqid);
751         newseq = be32_to_cpu(new->seqid);
752         if (empty || pnfs_seqid_is_newer(newseq, oldseq)) {
753                 nfs4_stateid_copy(&lo->plh_stateid, new);
754                 if (update_barrier) {
755                         new_barrier = be32_to_cpu(new->seqid);
756                 } else {
757                         /* Because of wraparound, we want to keep the barrier
758                          * "close" to the current seqids.
759                          */
760                         new_barrier = newseq - atomic_read(&lo->plh_outstanding);
761                 }
762                 if (empty || pnfs_seqid_is_newer(new_barrier, lo->plh_barrier))
763                         lo->plh_barrier = new_barrier;
764         }
765 }
766 
767 static bool
768 pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,
769                 const nfs4_stateid *stateid)
770 {
771         u32 seqid = be32_to_cpu(stateid->seqid);
772 
773         return !pnfs_seqid_is_newer(seqid, lo->plh_barrier);
774 }
775 
776 /* lget is set to 1 if called from inside send_layoutget call chain */
777 static bool
778 pnfs_layoutgets_blocked(const struct pnfs_layout_hdr *lo)
779 {
780         return lo->plh_block_lgets ||
781                 test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
782 }
783 
784 int
785 pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
786                               const struct pnfs_layout_range *range,
787                               struct nfs4_state *open_state)
788 {
789         int status = 0;
790 
791         dprintk("--> %s\n", __func__);
792         spin_lock(&lo->plh_inode->i_lock);
793         if (pnfs_layoutgets_blocked(lo)) {
794                 status = -EAGAIN;
795         } else if (!nfs4_valid_open_stateid(open_state)) {
796                 status = -EBADF;
797         } else if (list_empty(&lo->plh_segs) ||
798                    test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags)) {
799                 int seq;
800 
801                 do {
802                         seq = read_seqbegin(&open_state->seqlock);
803                         nfs4_stateid_copy(dst, &open_state->stateid);
804                 } while (read_seqretry(&open_state->seqlock, seq));
805         } else
806                 nfs4_stateid_copy(dst, &lo->plh_stateid);
807         spin_unlock(&lo->plh_inode->i_lock);
808         dprintk("<-- %s\n", __func__);
809         return status;
810 }
811 
812 /*
813 * Get layout from server.
814 *    for now, assume that whole file layouts are requested.
815 *    arg->offset: 0
816 *    arg->length: all ones
817 */
818 static struct pnfs_layout_segment *
819 send_layoutget(struct pnfs_layout_hdr *lo,
820            struct nfs_open_context *ctx,
821            const struct pnfs_layout_range *range,
822            gfp_t gfp_flags)
823 {
824         struct inode *ino = lo->plh_inode;
825         struct nfs_server *server = NFS_SERVER(ino);
826         struct nfs4_layoutget *lgp;
827         struct pnfs_layout_segment *lseg;
828         loff_t i_size;
829 
830         dprintk("--> %s\n", __func__);
831 
832         /*
833          * Synchronously retrieve layout information from server and
834          * store in lseg. If we race with a concurrent seqid morphing
835          * op, then re-send the LAYOUTGET.
836          */
837         do {
838                 lgp = kzalloc(sizeof(*lgp), gfp_flags);
839                 if (lgp == NULL)
840                         return NULL;
841 
842                 i_size = i_size_read(ino);
843 
844                 lgp->args.minlength = PAGE_CACHE_SIZE;
845                 if (lgp->args.minlength > range->length)
846                         lgp->args.minlength = range->length;
847                 if (range->iomode == IOMODE_READ) {
848                         if (range->offset >= i_size)
849                                 lgp->args.minlength = 0;
850                         else if (i_size - range->offset < lgp->args.minlength)
851                                 lgp->args.minlength = i_size - range->offset;
852                 }
853                 lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
854                 pnfs_copy_range(&lgp->args.range, range);
855                 lgp->args.type = server->pnfs_curr_ld->id;
856                 lgp->args.inode = ino;
857                 lgp->args.ctx = get_nfs_open_context(ctx);
858                 lgp->gfp_flags = gfp_flags;
859                 lgp->cred = lo->plh_lc_cred;
860 
861                 lseg = nfs4_proc_layoutget(lgp, gfp_flags);
862         } while (lseg == ERR_PTR(-EAGAIN));
863 
864         if (IS_ERR(lseg) && !nfs_error_is_fatal(PTR_ERR(lseg)))
865                 lseg = NULL;
866         else
867                 pnfs_layout_clear_fail_bit(lo,
868                                 pnfs_iomode_to_fail_bit(range->iomode));
869 
870         return lseg;
871 }
872 
873 static void pnfs_clear_layoutcommit(struct inode *inode,
874                 struct list_head *head)
875 {
876         struct nfs_inode *nfsi = NFS_I(inode);
877         struct pnfs_layout_segment *lseg, *tmp;
878 
879         if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
880                 return;
881         list_for_each_entry_safe(lseg, tmp, &nfsi->layout->plh_segs, pls_list) {
882                 if (!test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
883                         continue;
884                 pnfs_lseg_dec_and_remove_zero(lseg, head);
885         }
886 }
887 
888 void pnfs_clear_layoutreturn_waitbit(struct pnfs_layout_hdr *lo)
889 {
890         clear_bit_unlock(NFS_LAYOUT_RETURN, &lo->plh_flags);
891         smp_mb__after_atomic();
892         wake_up_bit(&lo->plh_flags, NFS_LAYOUT_RETURN);
893         rpc_wake_up(&NFS_SERVER(lo->plh_inode)->roc_rpcwaitq);
894 }
895 
896 static bool
897 pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo)
898 {
899         if (test_and_set_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))
900                 return false;
901         lo->plh_return_iomode = 0;
902         pnfs_get_layout_hdr(lo);
903         clear_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags);
904         return true;
905 }
906 
907 static int
908 pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo, const nfs4_stateid *stateid,
909                        enum pnfs_iomode iomode, bool sync)
910 {
911         struct inode *ino = lo->plh_inode;
912         struct nfs4_layoutreturn *lrp;
913         int status = 0;
914 
915         lrp = kzalloc(sizeof(*lrp), GFP_NOFS);
916         if (unlikely(lrp == NULL)) {
917                 status = -ENOMEM;
918                 spin_lock(&ino->i_lock);
919                 pnfs_clear_layoutreturn_waitbit(lo);
920                 spin_unlock(&ino->i_lock);
921                 pnfs_put_layout_hdr(lo);
922                 goto out;
923         }
924 
925         nfs4_stateid_copy(&lrp->args.stateid, stateid);
926         lrp->args.layout_type = NFS_SERVER(ino)->pnfs_curr_ld->id;
927         lrp->args.inode = ino;
928         lrp->args.range.iomode = iomode;
929         lrp->args.range.offset = 0;
930         lrp->args.range.length = NFS4_MAX_UINT64;
931         lrp->args.layout = lo;
932         lrp->clp = NFS_SERVER(ino)->nfs_client;
933         lrp->cred = lo->plh_lc_cred;
934 
935         status = nfs4_proc_layoutreturn(lrp, sync);
936 out:
937         dprintk("<-- %s status: %d\n", __func__, status);
938         return status;
939 }
940 
941 /* Return true if layoutreturn is needed */
942 static bool
943 pnfs_layout_need_return(struct pnfs_layout_hdr *lo)
944 {
945         struct pnfs_layout_segment *s;
946 
947         if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
948                 return false;
949 
950         /* Defer layoutreturn until all lsegs are done */
951         list_for_each_entry(s, &lo->plh_segs, pls_list) {
952                 if (test_bit(NFS_LSEG_LAYOUTRETURN, &s->pls_flags))
953                         return false;
954         }
955 
956         return true;
957 }
958 
959 static void pnfs_layoutreturn_before_put_layout_hdr(struct pnfs_layout_hdr *lo)
960 {
961         struct inode *inode= lo->plh_inode;
962 
963         if (!test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags))
964                 return;
965         spin_lock(&inode->i_lock);
966         if (pnfs_layout_need_return(lo)) {
967                 nfs4_stateid stateid;
968                 enum pnfs_iomode iomode;
969                 bool send;
970 
971                 nfs4_stateid_copy(&stateid, &lo->plh_stateid);
972                 iomode = lo->plh_return_iomode;
973                 send = pnfs_prepare_layoutreturn(lo);
974                 spin_unlock(&inode->i_lock);
975                 if (send) {
976                         /* Send an async layoutreturn so we dont deadlock */
977                         pnfs_send_layoutreturn(lo, &stateid, iomode, false);
978                 }
979         } else
980                 spin_unlock(&inode->i_lock);
981 }
982 
983 /*
984  * Initiates a LAYOUTRETURN(FILE), and removes the pnfs_layout_hdr
985  * when the layout segment list is empty.
986  *
987  * Note that a pnfs_layout_hdr can exist with an empty layout segment
988  * list when LAYOUTGET has failed, or when LAYOUTGET succeeded, but the
989  * deviceid is marked invalid.
990  */
991 int
992 _pnfs_return_layout(struct inode *ino)
993 {
994         struct pnfs_layout_hdr *lo = NULL;
995         struct nfs_inode *nfsi = NFS_I(ino);
996         LIST_HEAD(tmp_list);
997         nfs4_stateid stateid;
998         int status = 0, empty;
999         bool send;
1000 
1001         dprintk("NFS: %s for inode %lu\n", __func__, ino->i_ino);
1002 
1003         spin_lock(&ino->i_lock);
1004         lo = nfsi->layout;
1005         if (!lo) {
1006                 spin_unlock(&ino->i_lock);
1007                 dprintk("NFS: %s no layout to return\n", __func__);
1008                 goto out;
1009         }
1010         nfs4_stateid_copy(&stateid, &nfsi->layout->plh_stateid);
1011         /* Reference matched in nfs4_layoutreturn_release */
1012         pnfs_get_layout_hdr(lo);
1013         empty = list_empty(&lo->plh_segs);
1014         pnfs_clear_layoutcommit(ino, &tmp_list);
1015         pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
1016 
1017         if (NFS_SERVER(ino)->pnfs_curr_ld->return_range) {
1018                 struct pnfs_layout_range range = {
1019                         .iomode         = IOMODE_ANY,
1020                         .offset         = 0,
1021                         .length         = NFS4_MAX_UINT64,
1022                 };
1023                 NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo, &range);
1024         }
1025 
1026         /* Don't send a LAYOUTRETURN if list was initially empty */
1027         if (empty) {
1028                 spin_unlock(&ino->i_lock);
1029                 dprintk("NFS: %s no layout segments to return\n", __func__);
1030                 goto out_put_layout_hdr;
1031         }
1032 
1033         set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
1034         send = pnfs_prepare_layoutreturn(lo);
1035         spin_unlock(&ino->i_lock);
1036         pnfs_free_lseg_list(&tmp_list);
1037         if (send)
1038                 status = pnfs_send_layoutreturn(lo, &stateid, IOMODE_ANY, true);
1039 out_put_layout_hdr:
1040         pnfs_put_layout_hdr(lo);
1041 out:
1042         dprintk("<-- %s status: %d\n", __func__, status);
1043         return status;
1044 }
1045 EXPORT_SYMBOL_GPL(_pnfs_return_layout);
1046 
1047 int
1048 pnfs_commit_and_return_layout(struct inode *inode)
1049 {
1050         struct pnfs_layout_hdr *lo;
1051         int ret;
1052 
1053         spin_lock(&inode->i_lock);
1054         lo = NFS_I(inode)->layout;
1055         if (lo == NULL) {
1056                 spin_unlock(&inode->i_lock);
1057                 return 0;
1058         }
1059         pnfs_get_layout_hdr(lo);
1060         /* Block new layoutgets and read/write to ds */
1061         lo->plh_block_lgets++;
1062         spin_unlock(&inode->i_lock);
1063         filemap_fdatawait(inode->i_mapping);
1064         ret = pnfs_layoutcommit_inode(inode, true);
1065         if (ret == 0)
1066                 ret = _pnfs_return_layout(inode);
1067         spin_lock(&inode->i_lock);
1068         lo->plh_block_lgets--;
1069         spin_unlock(&inode->i_lock);
1070         pnfs_put_layout_hdr(lo);
1071         return ret;
1072 }
1073 
1074 bool pnfs_roc(struct inode *ino)
1075 {
1076         struct nfs_inode *nfsi = NFS_I(ino);
1077         struct nfs_open_context *ctx;
1078         struct nfs4_state *state;
1079         struct pnfs_layout_hdr *lo;
1080         struct pnfs_layout_segment *lseg, *tmp;
1081         nfs4_stateid stateid;
1082         LIST_HEAD(tmp_list);
1083         bool found = false, layoutreturn = false, roc = false;
1084 
1085         spin_lock(&ino->i_lock);
1086         lo = nfsi->layout;
1087         if (!lo || test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags))
1088                 goto out_noroc;
1089 
1090         /* no roc if we hold a delegation */
1091         if (nfs4_check_delegation(ino, FMODE_READ))
1092                 goto out_noroc;
1093 
1094         list_for_each_entry(ctx, &nfsi->open_files, list) {
1095                 state = ctx->state;
1096                 /* Don't return layout if there is open file state */
1097                 if (state != NULL && state->state != 0)
1098                         goto out_noroc;
1099         }
1100 
1101         nfs4_stateid_copy(&stateid, &lo->plh_stateid);
1102         /* always send layoutreturn if being marked so */
1103         if (test_and_clear_bit(NFS_LAYOUT_RETURN_REQUESTED,
1104                                    &lo->plh_flags))
1105                 layoutreturn = pnfs_prepare_layoutreturn(lo);
1106 
1107         list_for_each_entry_safe(lseg, tmp, &lo->plh_segs, pls_list)
1108                 /* If we are sending layoutreturn, invalidate all valid lsegs */
1109                 if (layoutreturn || test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
1110                         mark_lseg_invalid(lseg, &tmp_list);
1111                         found = true;
1112                 }
1113         /* ROC in two conditions:
1114          * 1. there are ROC lsegs
1115          * 2. we don't send layoutreturn
1116          */
1117         if (found && !layoutreturn) {
1118                 /* lo ref dropped in pnfs_roc_release() */
1119                 pnfs_get_layout_hdr(lo);
1120                 roc = true;
1121         }
1122 
1123 out_noroc:
1124         spin_unlock(&ino->i_lock);
1125         pnfs_free_lseg_list(&tmp_list);
1126         pnfs_layoutcommit_inode(ino, true);
1127         if (layoutreturn)
1128                 pnfs_send_layoutreturn(lo, &stateid, IOMODE_ANY, true);
1129         return roc;
1130 }
1131 
1132 void pnfs_roc_release(struct inode *ino)
1133 {
1134         struct pnfs_layout_hdr *lo;
1135 
1136         spin_lock(&ino->i_lock);
1137         lo = NFS_I(ino)->layout;
1138         pnfs_clear_layoutreturn_waitbit(lo);
1139         if (atomic_dec_and_test(&lo->plh_refcount)) {
1140                 pnfs_detach_layout_hdr(lo);
1141                 spin_unlock(&ino->i_lock);
1142                 pnfs_free_layout_hdr(lo);
1143         } else
1144                 spin_unlock(&ino->i_lock);
1145 }
1146 
1147 void pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
1148 {
1149         struct pnfs_layout_hdr *lo;
1150 
1151         spin_lock(&ino->i_lock);
1152         lo = NFS_I(ino)->layout;
1153         pnfs_mark_layout_returned_if_empty(lo);
1154         if (pnfs_seqid_is_newer(barrier, lo->plh_barrier))
1155                 lo->plh_barrier = barrier;
1156         spin_unlock(&ino->i_lock);
1157         trace_nfs4_layoutreturn_on_close(ino, 0);
1158 }
1159 
1160 void pnfs_roc_get_barrier(struct inode *ino, u32 *barrier)
1161 {
1162         struct nfs_inode *nfsi = NFS_I(ino);
1163         struct pnfs_layout_hdr *lo;
1164         u32 current_seqid;
1165 
1166         spin_lock(&ino->i_lock);
1167         lo = nfsi->layout;
1168         current_seqid = be32_to_cpu(lo->plh_stateid.seqid);
1169 
1170         /* Since close does not return a layout stateid for use as
1171          * a barrier, we choose the worst-case barrier.
1172          */
1173         *barrier = current_seqid + atomic_read(&lo->plh_outstanding);
1174         spin_unlock(&ino->i_lock);
1175 }
1176 
1177 bool pnfs_wait_on_layoutreturn(struct inode *ino, struct rpc_task *task)
1178 {
1179         struct nfs_inode *nfsi = NFS_I(ino);
1180         struct pnfs_layout_hdr *lo;
1181         bool sleep = false;
1182 
1183         /* we might not have grabbed lo reference. so need to check under
1184          * i_lock */
1185         spin_lock(&ino->i_lock);
1186         lo = nfsi->layout;
1187         if (lo && test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))
1188                 sleep = true;
1189         spin_unlock(&ino->i_lock);
1190 
1191         if (sleep)
1192                 rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);
1193 
1194         return sleep;
1195 }
1196 
1197 /*
1198  * Compare two layout segments for sorting into layout cache.
1199  * We want to preferentially return RW over RO layouts, so ensure those
1200  * are seen first.
1201  */
1202 static s64
1203 pnfs_lseg_range_cmp(const struct pnfs_layout_range *l1,
1204            const struct pnfs_layout_range *l2)
1205 {
1206         s64 d;
1207 
1208         /* high offset > low offset */
1209         d = l1->offset - l2->offset;
1210         if (d)
1211                 return d;
1212 
1213         /* short length > long length */
1214         d = l2->length - l1->length;
1215         if (d)
1216                 return d;
1217 
1218         /* read > read/write */
1219         return (int)(l1->iomode == IOMODE_READ) - (int)(l2->iomode == IOMODE_READ);
1220 }
1221 
1222 static bool
1223 pnfs_lseg_range_is_after(const struct pnfs_layout_range *l1,
1224                 const struct pnfs_layout_range *l2)
1225 {
1226         return pnfs_lseg_range_cmp(l1, l2) > 0;
1227 }
1228 
1229 static bool
1230 pnfs_lseg_no_merge(struct pnfs_layout_segment *lseg,
1231                 struct pnfs_layout_segment *old)
1232 {
1233         return false;
1234 }
1235 
1236 void
1237 pnfs_generic_layout_insert_lseg(struct pnfs_layout_hdr *lo,
1238                    struct pnfs_layout_segment *lseg,
1239                    bool (*is_after)(const struct pnfs_layout_range *,
1240                            const struct pnfs_layout_range *),
1241                    bool (*do_merge)(struct pnfs_layout_segment *,
1242                            struct pnfs_layout_segment *),
1243                    struct list_head *free_me)
1244 {
1245         struct pnfs_layout_segment *lp, *tmp;
1246 
1247         dprintk("%s:Begin\n", __func__);
1248 
1249         list_for_each_entry_safe(lp, tmp, &lo->plh_segs, pls_list) {
1250                 if (test_bit(NFS_LSEG_VALID, &lp->pls_flags) == 0)
1251                         continue;
1252                 if (do_merge(lseg, lp)) {
1253                         mark_lseg_invalid(lp, free_me);
1254                         continue;
1255                 }
1256                 if (is_after(&lseg->pls_range, &lp->pls_range))
1257                         continue;
1258                 list_add_tail(&lseg->pls_list, &lp->pls_list);
1259                 dprintk("%s: inserted lseg %p "
1260                         "iomode %d offset %llu length %llu before "
1261                         "lp %p iomode %d offset %llu length %llu\n",
1262                         __func__, lseg, lseg->pls_range.iomode,
1263                         lseg->pls_range.offset, lseg->pls_range.length,
1264                         lp, lp->pls_range.iomode, lp->pls_range.offset,
1265                         lp->pls_range.length);
1266                 goto out;
1267         }
1268         list_add_tail(&lseg->pls_list, &lo->plh_segs);
1269         dprintk("%s: inserted lseg %p "
1270                 "iomode %d offset %llu length %llu at tail\n",
1271                 __func__, lseg, lseg->pls_range.iomode,
1272                 lseg->pls_range.offset, lseg->pls_range.length);
1273 out:
1274         pnfs_get_layout_hdr(lo);
1275 
1276         dprintk("%s:Return\n", __func__);
1277 }
1278 EXPORT_SYMBOL_GPL(pnfs_generic_layout_insert_lseg);
1279 
1280 static void
1281 pnfs_layout_insert_lseg(struct pnfs_layout_hdr *lo,
1282                    struct pnfs_layout_segment *lseg,
1283                    struct list_head *free_me)
1284 {
1285         struct inode *inode = lo->plh_inode;
1286         struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
1287 
1288         if (ld->add_lseg != NULL)
1289                 ld->add_lseg(lo, lseg, free_me);
1290         else
1291                 pnfs_generic_layout_insert_lseg(lo, lseg,
1292                                 pnfs_lseg_range_is_after,
1293                                 pnfs_lseg_no_merge,
1294                                 free_me);
1295 }
1296 
1297 static struct pnfs_layout_hdr *
1298 alloc_init_layout_hdr(struct inode *ino,
1299                       struct nfs_open_context *ctx,
1300                       gfp_t gfp_flags)
1301 {
1302         struct pnfs_layout_hdr *lo;
1303 
1304         lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
1305         if (!lo)
1306                 return NULL;
1307         atomic_set(&lo->plh_refcount, 1);
1308         INIT_LIST_HEAD(&lo->plh_layouts);
1309         INIT_LIST_HEAD(&lo->plh_segs);
1310         INIT_LIST_HEAD(&lo->plh_bulk_destroy);
1311         lo->plh_inode = ino;
1312         lo->plh_lc_cred = get_rpccred(ctx->cred);
1313         return lo;
1314 }
1315 
1316 static struct pnfs_layout_hdr *
1317 pnfs_find_alloc_layout(struct inode *ino,
1318                        struct nfs_open_context *ctx,
1319                        gfp_t gfp_flags)
1320 {
1321         struct nfs_inode *nfsi = NFS_I(ino);
1322         struct pnfs_layout_hdr *new = NULL;
1323 
1324         dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
1325 
1326         if (nfsi->layout != NULL)
1327                 goto out_existing;
1328         spin_unlock(&ino->i_lock);
1329         new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
1330         spin_lock(&ino->i_lock);
1331 
1332         if (likely(nfsi->layout == NULL)) {     /* Won the race? */
1333                 nfsi->layout = new;
1334                 return new;
1335         } else if (new != NULL)
1336                 pnfs_free_layout_hdr(new);
1337 out_existing:
1338         pnfs_get_layout_hdr(nfsi->layout);
1339         return nfsi->layout;
1340 }
1341 
1342 /*
1343  * iomode matching rules:
1344  * iomode       lseg    match
1345  * -----        -----   -----
1346  * ANY          READ    true
1347  * ANY          RW      true
1348  * RW           READ    false
1349  * RW           RW      true
1350  * READ         READ    true
1351  * READ         RW      true
1352  */
1353 static bool
1354 pnfs_lseg_range_match(const struct pnfs_layout_range *ls_range,
1355                  const struct pnfs_layout_range *range)
1356 {
1357         struct pnfs_layout_range range1;
1358 
1359         if ((range->iomode == IOMODE_RW &&
1360              ls_range->iomode != IOMODE_RW) ||
1361             !pnfs_lseg_range_intersecting(ls_range, range))
1362                 return 0;
1363 
1364         /* range1 covers only the first byte in the range */
1365         range1 = *range;
1366         range1.length = 1;
1367         return pnfs_lseg_range_contained(ls_range, &range1);
1368 }
1369 
1370 /*
1371  * lookup range in layout
1372  */
1373 static struct pnfs_layout_segment *
1374 pnfs_find_lseg(struct pnfs_layout_hdr *lo,
1375                 struct pnfs_layout_range *range)
1376 {
1377         struct pnfs_layout_segment *lseg, *ret = NULL;
1378 
1379         dprintk("%s:Begin\n", __func__);
1380 
1381         list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
1382                 if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
1383                     !test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags) &&
1384                     pnfs_lseg_range_match(&lseg->pls_range, range)) {
1385                         ret = pnfs_get_lseg(lseg);
1386                         break;
1387                 }
1388         }
1389 
1390         dprintk("%s:Return lseg %p ref %d\n",
1391                 __func__, ret, ret ? atomic_read(&ret->pls_refcount) : 0);
1392         return ret;
1393 }
1394 
1395 /*
1396  * Use mdsthreshold hints set at each OPEN to determine if I/O should go
1397  * to the MDS or over pNFS
1398  *
1399  * The nfs_inode read_io and write_io fields are cumulative counters reset
1400  * when there are no layout segments. Note that in pnfs_update_layout iomode
1401  * is set to IOMODE_READ for a READ request, and set to IOMODE_RW for a
1402  * WRITE request.
1403  *
1404  * A return of true means use MDS I/O.
1405  *
1406  * From rfc 5661:
1407  * If a file's size is smaller than the file size threshold, data accesses
1408  * SHOULD be sent to the metadata server.  If an I/O request has a length that
1409  * is below the I/O size threshold, the I/O SHOULD be sent to the metadata
1410  * server.  If both file size and I/O size are provided, the client SHOULD
1411  * reach or exceed  both thresholds before sending its read or write
1412  * requests to the data server.
1413  */
1414 static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx,
1415                                      struct inode *ino, int iomode)
1416 {
1417         struct nfs4_threshold *t = ctx->mdsthreshold;
1418         struct nfs_inode *nfsi = NFS_I(ino);
1419         loff_t fsize = i_size_read(ino);
1420         bool size = false, size_set = false, io = false, io_set = false, ret = false;
1421 
1422         if (t == NULL)
1423                 return ret;
1424 
1425         dprintk("%s bm=0x%x rd_sz=%llu wr_sz=%llu rd_io=%llu wr_io=%llu\n",
1426                 __func__, t->bm, t->rd_sz, t->wr_sz, t->rd_io_sz, t->wr_io_sz);
1427 
1428         switch (iomode) {
1429         case IOMODE_READ:
1430                 if (t->bm & THRESHOLD_RD) {
1431                         dprintk("%s fsize %llu\n", __func__, fsize);
1432                         size_set = true;
1433                         if (fsize < t->rd_sz)
1434                                 size = true;
1435                 }
1436                 if (t->bm & THRESHOLD_RD_IO) {
1437                         dprintk("%s nfsi->read_io %llu\n", __func__,
1438                                 nfsi->read_io);
1439                         io_set = true;
1440                         if (nfsi->read_io < t->rd_io_sz)
1441                                 io = true;
1442                 }
1443                 break;
1444         case IOMODE_RW:
1445                 if (t->bm & THRESHOLD_WR) {
1446                         dprintk("%s fsize %llu\n", __func__, fsize);
1447                         size_set = true;
1448                         if (fsize < t->wr_sz)
1449                                 size = true;
1450                 }
1451                 if (t->bm & THRESHOLD_WR_IO) {
1452                         dprintk("%s nfsi->write_io %llu\n", __func__,
1453                                 nfsi->write_io);
1454                         io_set = true;
1455                         if (nfsi->write_io < t->wr_io_sz)
1456                                 io = true;
1457                 }
1458                 break;
1459         }
1460         if (size_set && io_set) {
1461                 if (size && io)
1462                         ret = true;
1463         } else if (size || io)
1464                 ret = true;
1465 
1466         dprintk("<-- %s size %d io %d ret %d\n", __func__, size, io, ret);
1467         return ret;
1468 }
1469 
1470 static bool pnfs_prepare_to_retry_layoutget(struct pnfs_layout_hdr *lo)
1471 {
1472         /*
1473          * send layoutcommit as it can hold up layoutreturn due to lseg
1474          * reference
1475          */
1476         pnfs_layoutcommit_inode(lo->plh_inode, false);
1477         return !wait_on_bit_action(&lo->plh_flags, NFS_LAYOUT_RETURN,
1478                                    nfs_wait_bit_killable,
1479                                    TASK_UNINTERRUPTIBLE);
1480 }
1481 
1482 static void pnfs_clear_first_layoutget(struct pnfs_layout_hdr *lo)
1483 {
1484         unsigned long *bitlock = &lo->plh_flags;
1485 
1486         clear_bit_unlock(NFS_LAYOUT_FIRST_LAYOUTGET, bitlock);
1487         smp_mb__after_atomic();
1488         wake_up_bit(bitlock, NFS_LAYOUT_FIRST_LAYOUTGET);
1489 }
1490 
1491 /*
1492  * Layout segment is retreived from the server if not cached.
1493  * The appropriate layout segment is referenced and returned to the caller.
1494  */
1495 struct pnfs_layout_segment *
1496 pnfs_update_layout(struct inode *ino,
1497                    struct nfs_open_context *ctx,
1498                    loff_t pos,
1499                    u64 count,
1500                    enum pnfs_iomode iomode,
1501                    gfp_t gfp_flags)
1502 {
1503         struct pnfs_layout_range arg = {
1504                 .iomode = iomode,
1505                 .offset = pos,
1506                 .length = count,
1507         };
1508         unsigned pg_offset;
1509         struct nfs_server *server = NFS_SERVER(ino);
1510         struct nfs_client *clp = server->nfs_client;
1511         struct pnfs_layout_hdr *lo;
1512         struct pnfs_layout_segment *lseg = NULL;
1513         bool first;
1514 
1515         if (!pnfs_enabled_sb(NFS_SERVER(ino))) {
1516                 trace_pnfs_update_layout(ino, pos, count, iomode, NULL,
1517                                  PNFS_UPDATE_LAYOUT_NO_PNFS);
1518                 goto out;
1519         }
1520 
1521         if (iomode == IOMODE_READ && i_size_read(ino) == 0) {
1522                 trace_pnfs_update_layout(ino, pos, count, iomode, NULL,
1523                                  PNFS_UPDATE_LAYOUT_RD_ZEROLEN);
1524                 goto out;
1525         }
1526 
1527         if (pnfs_within_mdsthreshold(ctx, ino, iomode)) {
1528                 trace_pnfs_update_layout(ino, pos, count, iomode, NULL,
1529                                  PNFS_UPDATE_LAYOUT_MDSTHRESH);
1530                 goto out;
1531         }
1532 
1533 lookup_again:
1534         first = false;
1535         spin_lock(&ino->i_lock);
1536         lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
1537         if (lo == NULL) {
1538                 spin_unlock(&ino->i_lock);
1539                 trace_pnfs_update_layout(ino, pos, count, iomode, NULL,
1540                                  PNFS_UPDATE_LAYOUT_NOMEM);
1541                 goto out;
1542         }
1543 
1544         /* Do we even need to bother with this? */
1545         if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1546                 trace_pnfs_update_layout(ino, pos, count, iomode, lo,
1547                                  PNFS_UPDATE_LAYOUT_BULK_RECALL);
1548                 dprintk("%s matches recall, use MDS\n", __func__);
1549                 goto out_unlock;
1550         }
1551 
1552         /* if LAYOUTGET already failed once we don't try again */
1553         if (pnfs_layout_io_test_failed(lo, iomode)) {
1554                 trace_pnfs_update_layout(ino, pos, count, iomode, lo,
1555                                  PNFS_UPDATE_LAYOUT_IO_TEST_FAIL);
1556                 goto out_unlock;
1557         }
1558 
1559         first = list_empty(&lo->plh_segs);
1560         if (first) {
1561                 /* The first layoutget for the file. Need to serialize per
1562                  * RFC 5661 Errata 3208.
1563                  */
1564                 if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET,
1565                                      &lo->plh_flags)) {
1566                         spin_unlock(&ino->i_lock);
1567                         wait_on_bit(&lo->plh_flags, NFS_LAYOUT_FIRST_LAYOUTGET,
1568                                     TASK_UNINTERRUPTIBLE);
1569                         pnfs_put_layout_hdr(lo);
1570                         goto lookup_again;
1571                 }
1572         } else {
1573                 /* Check to see if the layout for the given range
1574                  * already exists
1575                  */
1576                 lseg = pnfs_find_lseg(lo, &arg);
1577                 if (lseg) {
1578                         trace_pnfs_update_layout(ino, pos, count, iomode, lo,
1579                                         PNFS_UPDATE_LAYOUT_FOUND_CACHED);
1580                         goto out_unlock;
1581                 }
1582         }
1583 
1584         /*
1585          * Because we free lsegs before sending LAYOUTRETURN, we need to wait
1586          * for LAYOUTRETURN even if first is true.
1587          */
1588         if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
1589                 spin_unlock(&ino->i_lock);
1590                 dprintk("%s wait for layoutreturn\n", __func__);
1591                 if (pnfs_prepare_to_retry_layoutget(lo)) {
1592                         if (first)
1593                                 pnfs_clear_first_layoutget(lo);
1594                         pnfs_put_layout_hdr(lo);
1595                         dprintk("%s retrying\n", __func__);
1596                         goto lookup_again;
1597                 }
1598                 trace_pnfs_update_layout(ino, pos, count, iomode, lo,
1599                                 PNFS_UPDATE_LAYOUT_RETURN);
1600                 goto out_put_layout_hdr;
1601         }
1602 
1603         if (pnfs_layoutgets_blocked(lo)) {
1604                 trace_pnfs_update_layout(ino, pos, count, iomode, lo,
1605                                 PNFS_UPDATE_LAYOUT_BLOCKED);
1606                 goto out_unlock;
1607         }
1608         atomic_inc(&lo->plh_outstanding);
1609         spin_unlock(&ino->i_lock);
1610 
1611         if (list_empty(&lo->plh_layouts)) {
1612                 /* The lo must be on the clp list if there is any
1613                  * chance of a CB_LAYOUTRECALL(FILE) coming in.
1614                  */
1615                 spin_lock(&clp->cl_lock);
1616                 if (list_empty(&lo->plh_layouts))
1617                         list_add_tail(&lo->plh_layouts, &server->layouts);
1618                 spin_unlock(&clp->cl_lock);
1619         }
1620 
1621         pg_offset = arg.offset & ~PAGE_CACHE_MASK;
1622         if (pg_offset) {
1623                 arg.offset -= pg_offset;
1624                 arg.length += pg_offset;
1625         }
1626         if (arg.length != NFS4_MAX_UINT64)
1627                 arg.length = PAGE_CACHE_ALIGN(arg.length);
1628 
1629         lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
1630         atomic_dec(&lo->plh_outstanding);
1631         trace_pnfs_update_layout(ino, pos, count, iomode, lo,
1632                                  PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET);
1633 out_put_layout_hdr:
1634         if (first)
1635                 pnfs_clear_first_layoutget(lo);
1636         pnfs_put_layout_hdr(lo);
1637 out:
1638         dprintk("%s: inode %s/%llu pNFS layout segment %s for "
1639                         "(%s, offset: %llu, length: %llu)\n",
1640                         __func__, ino->i_sb->s_id,
1641                         (unsigned long long)NFS_FILEID(ino),
1642                         IS_ERR_OR_NULL(lseg) ? "not found" : "found",
1643                         iomode==IOMODE_RW ?  "read/write" : "read-only",
1644                         (unsigned long long)pos,
1645                         (unsigned long long)count);
1646         return lseg;
1647 out_unlock:
1648         spin_unlock(&ino->i_lock);
1649         goto out_put_layout_hdr;
1650 }
1651 EXPORT_SYMBOL_GPL(pnfs_update_layout);
1652 
1653 static bool
1654 pnfs_sanity_check_layout_range(struct pnfs_layout_range *range)
1655 {
1656         switch (range->iomode) {
1657         case IOMODE_READ:
1658         case IOMODE_RW:
1659                 break;
1660         default:
1661                 return false;
1662         }
1663         if (range->offset == NFS4_MAX_UINT64)
1664                 return false;
1665         if (range->length == 0)
1666                 return false;
1667         if (range->length != NFS4_MAX_UINT64 &&
1668             range->length > NFS4_MAX_UINT64 - range->offset)
1669                 return false;
1670         return true;
1671 }
1672 
1673 struct pnfs_layout_segment *
1674 pnfs_layout_process(struct nfs4_layoutget *lgp)
1675 {
1676         struct pnfs_layout_hdr *lo = NFS_I(lgp->args.inode)->layout;
1677         struct nfs4_layoutget_res *res = &lgp->res;
1678         struct pnfs_layout_segment *lseg;
1679         struct inode *ino = lo->plh_inode;
1680         LIST_HEAD(free_me);
1681         int status = -EINVAL;
1682 
1683         if (!pnfs_sanity_check_layout_range(&res->range))
1684                 goto out;
1685 
1686         /* Inject layout blob into I/O device driver */
1687         lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
1688         if (!lseg || IS_ERR(lseg)) {
1689                 if (!lseg)
1690                         status = -ENOMEM;
1691                 else
1692                         status = PTR_ERR(lseg);
1693                 dprintk("%s: Could not allocate layout: error %d\n",
1694                        __func__, status);
1695                 goto out;
1696         }
1697 
1698         init_lseg(lo, lseg);
1699         lseg->pls_range = res->range;
1700 
1701         spin_lock(&ino->i_lock);
1702         if (pnfs_layoutgets_blocked(lo)) {
1703                 dprintk("%s forget reply due to state\n", __func__);
1704                 goto out_forget_reply;
1705         }
1706 
1707         if (nfs4_stateid_match_other(&lo->plh_stateid, &res->stateid)) {
1708                 /* existing state ID, make sure the sequence number matches. */
1709                 if (pnfs_layout_stateid_blocked(lo, &res->stateid)) {
1710                         dprintk("%s forget reply due to sequence\n", __func__);
1711                         status = -EAGAIN;
1712                         goto out_forget_reply;
1713                 }
1714                 pnfs_set_layout_stateid(lo, &res->stateid, false);
1715         } else {
1716                 /*
1717                  * We got an entirely new state ID.  Mark all segments for the
1718                  * inode invalid, and don't bother validating the stateid
1719                  * sequence number.
1720                  */
1721                 pnfs_mark_matching_lsegs_invalid(lo, &free_me, NULL);
1722 
1723                 nfs4_stateid_copy(&lo->plh_stateid, &res->stateid);
1724                 lo->plh_barrier = be32_to_cpu(res->stateid.seqid);
1725         }
1726 
1727         clear_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
1728 
1729         pnfs_get_lseg(lseg);
1730         pnfs_layout_insert_lseg(lo, lseg, &free_me);
1731 
1732         if (res->return_on_close)
1733                 set_bit(NFS_LSEG_ROC, &lseg->pls_flags);
1734 
1735         spin_unlock(&ino->i_lock);
1736         pnfs_free_lseg_list(&free_me);
1737         return lseg;
1738 out:
1739         return ERR_PTR(status);
1740 
1741 out_forget_reply:
1742         spin_unlock(&ino->i_lock);
1743         lseg->pls_layout = lo;
1744         NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
1745         goto out;
1746 }
1747 
1748 static void
1749 pnfs_set_plh_return_iomode(struct pnfs_layout_hdr *lo, enum pnfs_iomode iomode)
1750 {
1751         if (lo->plh_return_iomode == iomode)
1752                 return;
1753         if (lo->plh_return_iomode != 0)
1754                 iomode = IOMODE_ANY;
1755         lo->plh_return_iomode = iomode;
1756         set_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags);
1757 }
1758 
1759 /**
1760  * pnfs_mark_matching_lsegs_return - Free or return matching layout segments
1761  * @lo: pointer to layout header
1762  * @tmp_list: list header to be used with pnfs_free_lseg_list()
1763  * @return_range: describe layout segment ranges to be returned
1764  *
1765  * This function is mainly intended for use by layoutrecall. It attempts
1766  * to free the layout segment immediately, or else to mark it for return
1767  * as soon as its reference count drops to zero.
1768  */
1769 int
1770 pnfs_mark_matching_lsegs_return(struct pnfs_layout_hdr *lo,
1771                                 struct list_head *tmp_list,
1772                                 const struct pnfs_layout_range *return_range)
1773 {
1774         struct pnfs_layout_segment *lseg, *next;
1775         int remaining = 0;
1776 
1777         dprintk("%s:Begin lo %p\n", __func__, lo);
1778 
1779         if (list_empty(&lo->plh_segs))
1780                 return 0;
1781 
1782         assert_spin_locked(&lo->plh_inode->i_lock);
1783 
1784         list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
1785                 if (should_free_lseg(&lseg->pls_range, return_range)) {
1786                         dprintk("%s: marking lseg %p iomode %d "
1787                                 "offset %llu length %llu\n", __func__,
1788                                 lseg, lseg->pls_range.iomode,
1789                                 lseg->pls_range.offset,
1790                                 lseg->pls_range.length);
1791                         if (mark_lseg_invalid(lseg, tmp_list))
1792                                 continue;
1793                         remaining++;
1794                         set_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
1795                         pnfs_set_plh_return_iomode(lo, return_range->iomode);
1796                 }
1797         return remaining;
1798 }
1799 
1800 void pnfs_error_mark_layout_for_return(struct inode *inode,
1801                                        struct pnfs_layout_segment *lseg)
1802 {
1803         struct pnfs_layout_hdr *lo = NFS_I(inode)->layout;
1804         struct pnfs_layout_range range = {
1805                 .iomode = lseg->pls_range.iomode,
1806                 .offset = 0,
1807                 .length = NFS4_MAX_UINT64,
1808         };
1809         LIST_HEAD(free_me);
1810         bool return_now = false;
1811 
1812         spin_lock(&inode->i_lock);
1813         pnfs_set_plh_return_iomode(lo, range.iomode);
1814         /*
1815          * mark all matching lsegs so that we are sure to have no live
1816          * segments at hand when sending layoutreturn. See pnfs_put_lseg()
1817          * for how it works.
1818          */
1819         if (!pnfs_mark_matching_lsegs_return(lo, &free_me, &range)) {
1820                 nfs4_stateid stateid;
1821                 enum pnfs_iomode iomode = lo->plh_return_iomode;
1822 
1823                 nfs4_stateid_copy(&stateid, &lo->plh_stateid);
1824                 return_now = pnfs_prepare_layoutreturn(lo);
1825                 spin_unlock(&inode->i_lock);
1826                 if (return_now)
1827                         pnfs_send_layoutreturn(lo, &stateid, iomode, false);
1828         } else {
1829                 spin_unlock(&inode->i_lock);
1830                 nfs_commit_inode(inode, 0);
1831         }
1832         pnfs_free_lseg_list(&free_me);
1833 }
1834 EXPORT_SYMBOL_GPL(pnfs_error_mark_layout_for_return);
1835 
1836 void
1837 pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
1838 {
1839         u64 rd_size = req->wb_bytes;
1840 
1841         if (pgio->pg_lseg == NULL) {
1842                 if (pgio->pg_dreq == NULL)
1843                         rd_size = i_size_read(pgio->pg_inode) - req_offset(req);
1844                 else
1845                         rd_size = nfs_dreq_bytes_left(pgio->pg_dreq);
1846 
1847                 pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1848                                                    req->wb_context,
1849                                                    req_offset(req),
1850                                                    rd_size,
1851                                                    IOMODE_READ,
1852                                                    GFP_KERNEL);
1853                 if (IS_ERR(pgio->pg_lseg)) {
1854                         pgio->pg_error = PTR_ERR(pgio->pg_lseg);
1855                         pgio->pg_lseg = NULL;
1856                         return;
1857                 }
1858         }
1859         /* If no lseg, fall back to read through mds */
1860         if (pgio->pg_lseg == NULL)
1861                 nfs_pageio_reset_read_mds(pgio);
1862 
1863 }
1864 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_read);
1865 
1866 void
1867 pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
1868                            struct nfs_page *req, u64 wb_size)
1869 {
1870         if (pgio->pg_lseg == NULL) {
1871                 pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1872                                                    req->wb_context,
1873                                                    req_offset(req),
1874                                                    wb_size,
1875                                                    IOMODE_RW,
1876                                                    GFP_NOFS);
1877                 if (IS_ERR(pgio->pg_lseg)) {
1878                         pgio->pg_error = PTR_ERR(pgio->pg_lseg);
1879                         pgio->pg_lseg = NULL;
1880                         return;
1881                 }
1882         }
1883         /* If no lseg, fall back to write through mds */
1884         if (pgio->pg_lseg == NULL)
1885                 nfs_pageio_reset_write_mds(pgio);
1886 }
1887 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
1888 
1889 void
1890 pnfs_generic_pg_cleanup(struct nfs_pageio_descriptor *desc)
1891 {
1892         if (desc->pg_lseg) {
1893                 pnfs_put_lseg(desc->pg_lseg);
1894                 desc->pg_lseg = NULL;
1895         }
1896 }
1897 EXPORT_SYMBOL_GPL(pnfs_generic_pg_cleanup);
1898 
1899 /*
1900  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
1901  * of bytes (maximum @req->wb_bytes) that can be coalesced.
1902  */
1903 size_t
1904 pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio,
1905                      struct nfs_page *prev, struct nfs_page *req)
1906 {
1907         unsigned int size;
1908         u64 seg_end, req_start, seg_left;
1909 
1910         size = nfs_generic_pg_test(pgio, prev, req);
1911         if (!size)
1912                 return 0;
1913 
1914         /*
1915          * 'size' contains the number of bytes left in the current page (up
1916          * to the original size asked for in @req->wb_bytes).
1917          *
1918          * Calculate how many bytes are left in the layout segment
1919          * and if there are less bytes than 'size', return that instead.
1920          *
1921          * Please also note that 'end_offset' is actually the offset of the
1922          * first byte that lies outside the pnfs_layout_range. FIXME?
1923          *
1924          */
1925         if (pgio->pg_lseg) {
1926                 seg_end = end_offset(pgio->pg_lseg->pls_range.offset,
1927                                      pgio->pg_lseg->pls_range.length);
1928                 req_start = req_offset(req);
1929                 WARN_ON_ONCE(req_start >= seg_end);
1930                 /* start of request is past the last byte of this segment */
1931                 if (req_start >= seg_end) {
1932                         /* reference the new lseg */
1933                         if (pgio->pg_ops->pg_cleanup)
1934                                 pgio->pg_ops->pg_cleanup(pgio);
1935                         if (pgio->pg_ops->pg_init)
1936                                 pgio->pg_ops->pg_init(pgio, req);
1937                         return 0;
1938                 }
1939 
1940                 /* adjust 'size' iff there are fewer bytes left in the
1941                  * segment than what nfs_generic_pg_test returned */
1942                 seg_left = seg_end - req_start;
1943                 if (seg_left < size)
1944                         size = (unsigned int)seg_left;
1945         }
1946 
1947         return size;
1948 }
1949 EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
1950 
1951 int pnfs_write_done_resend_to_mds(struct nfs_pgio_header *hdr)
1952 {
1953         struct nfs_pageio_descriptor pgio;
1954 
1955         /* Resend all requests through the MDS */
1956         nfs_pageio_init_write(&pgio, hdr->inode, FLUSH_STABLE, true,
1957                               hdr->completion_ops);
1958         set_bit(NFS_CONTEXT_RESEND_WRITES, &hdr->args.context->flags);
1959         return nfs_pageio_resend(&pgio, hdr);
1960 }
1961 EXPORT_SYMBOL_GPL(pnfs_write_done_resend_to_mds);
1962 
1963 static void pnfs_ld_handle_write_error(struct nfs_pgio_header *hdr)
1964 {
1965 
1966         dprintk("pnfs write error = %d\n", hdr->pnfs_error);
1967         if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
1968             PNFS_LAYOUTRET_ON_ERROR) {
1969                 pnfs_return_layout(hdr->inode);
1970         }
1971         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
1972                 hdr->task.tk_status = pnfs_write_done_resend_to_mds(hdr);
1973 }
1974 
1975 /*
1976  * Called by non rpc-based layout drivers
1977  */
1978 void pnfs_ld_write_done(struct nfs_pgio_header *hdr)
1979 {
1980         if (likely(!hdr->pnfs_error)) {
1981                 pnfs_set_layoutcommit(hdr->inode, hdr->lseg,
1982                                 hdr->mds_offset + hdr->res.count);
1983                 hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
1984         }
1985         trace_nfs4_pnfs_write(hdr, hdr->pnfs_error);
1986         if (unlikely(hdr->pnfs_error))
1987                 pnfs_ld_handle_write_error(hdr);
1988         hdr->mds_ops->rpc_release(hdr);
1989 }
1990 EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
1991 
1992 static void
1993 pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
1994                 struct nfs_pgio_header *hdr)
1995 {
1996         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1997 
1998         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1999                 list_splice_tail_init(&hdr->pages, &mirror->pg_list);
2000                 nfs_pageio_reset_write_mds(desc);
2001                 mirror->pg_recoalesce = 1;
2002         }
2003         nfs_pgio_data_destroy(hdr);
2004         hdr->release(hdr);
2005 }
2006 
2007 static enum pnfs_try_status
2008 pnfs_try_to_write_data(struct nfs_pgio_header *hdr,
2009                         const struct rpc_call_ops *call_ops,
2010                         struct pnfs_layout_segment *lseg,
2011                         int how)
2012 {
2013         struct inode *inode = hdr->inode;
2014         enum pnfs_try_status trypnfs;
2015         struct nfs_server *nfss = NFS_SERVER(inode);
2016 
2017         hdr->mds_ops = call_ops;
2018 
2019         dprintk("%s: Writing ino:%lu %u@%llu (how %d)\n", __func__,
2020                 inode->i_ino, hdr->args.count, hdr->args.offset, how);
2021         trypnfs = nfss->pnfs_curr_ld->write_pagelist(hdr, how);
2022         if (trypnfs != PNFS_NOT_ATTEMPTED)
2023                 nfs_inc_stats(inode, NFSIOS_PNFS_WRITE);
2024         dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
2025         return trypnfs;
2026 }
2027 
2028 static void
2029 pnfs_do_write(struct nfs_pageio_descriptor *desc,
2030               struct nfs_pgio_header *hdr, int how)
2031 {
2032         const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
2033         struct pnfs_layout_segment *lseg = desc->pg_lseg;
2034         enum pnfs_try_status trypnfs;
2035 
2036         trypnfs = pnfs_try_to_write_data(hdr, call_ops, lseg, how);
2037         if (trypnfs == PNFS_NOT_ATTEMPTED)
2038                 pnfs_write_through_mds(desc, hdr);
2039 }
2040 
2041 static void pnfs_writehdr_free(struct nfs_pgio_header *hdr)
2042 {
2043         pnfs_put_lseg(hdr->lseg);
2044         nfs_pgio_header_free(hdr);
2045 }
2046 
2047 int
2048 pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
2049 {
2050         struct nfs_pgio_header *hdr;
2051         int ret;
2052 
2053         hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
2054         if (!hdr) {
2055                 desc->pg_error = -ENOMEM;
2056                 return desc->pg_error;
2057         }
2058         nfs_pgheader_init(desc, hdr, pnfs_writehdr_free);
2059 
2060         hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
2061         ret = nfs_generic_pgio(desc, hdr);
2062         if (!ret)
2063                 pnfs_do_write(desc, hdr, desc->pg_ioflags);
2064 
2065         return ret;
2066 }
2067 EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
2068 
2069 int pnfs_read_done_resend_to_mds(struct nfs_pgio_header *hdr)
2070 {
2071         struct nfs_pageio_descriptor pgio;
2072 
2073         /* Resend all requests through the MDS */
2074         nfs_pageio_init_read(&pgio, hdr->inode, true, hdr->completion_ops);
2075         return nfs_pageio_resend(&pgio, hdr);
2076 }
2077 EXPORT_SYMBOL_GPL(pnfs_read_done_resend_to_mds);
2078 
2079 static void pnfs_ld_handle_read_error(struct nfs_pgio_header *hdr)
2080 {
2081         dprintk("pnfs read error = %d\n", hdr->pnfs_error);
2082         if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
2083             PNFS_LAYOUTRET_ON_ERROR) {
2084                 pnfs_return_layout(hdr->inode);
2085         }
2086         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
2087                 hdr->task.tk_status = pnfs_read_done_resend_to_mds(hdr);
2088 }
2089 
2090 /*
2091  * Called by non rpc-based layout drivers
2092  */
2093 void pnfs_ld_read_done(struct nfs_pgio_header *hdr)
2094 {
2095         if (likely(!hdr->pnfs_error)) {
2096                 __nfs4_read_done_cb(hdr);
2097                 hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
2098         }
2099         trace_nfs4_pnfs_read(hdr, hdr->pnfs_error);
2100         if (unlikely(hdr->pnfs_error))
2101                 pnfs_ld_handle_read_error(hdr);
2102         hdr->mds_ops->rpc_release(hdr);
2103 }
2104 EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
2105 
2106 static void
2107 pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
2108                 struct nfs_pgio_header *hdr)
2109 {
2110         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
2111 
2112         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
2113                 list_splice_tail_init(&hdr->pages, &mirror->pg_list);
2114                 nfs_pageio_reset_read_mds(desc);
2115                 mirror->pg_recoalesce = 1;
2116         }
2117         nfs_pgio_data_destroy(hdr);
2118         hdr->release(hdr);
2119 }
2120 
2121 /*
2122  * Call the appropriate parallel I/O subsystem read function.
2123  */
2124 static enum pnfs_try_status
2125 pnfs_try_to_read_data(struct nfs_pgio_header *hdr,
2126                        const struct rpc_call_ops *call_ops,
2127                        struct pnfs_layout_segment *lseg)
2128 {
2129         struct inode *inode = hdr->inode;
2130         struct nfs_server *nfss = NFS_SERVER(inode);
2131         enum pnfs_try_status trypnfs;
2132 
2133         hdr->mds_ops = call_ops;
2134 
2135         dprintk("%s: Reading ino:%lu %u@%llu\n",
2136                 __func__, inode->i_ino, hdr->args.count, hdr->args.offset);
2137 
2138         trypnfs = nfss->pnfs_curr_ld->read_pagelist(hdr);
2139         if (trypnfs != PNFS_NOT_ATTEMPTED)
2140                 nfs_inc_stats(inode, NFSIOS_PNFS_READ);
2141         dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
2142         return trypnfs;
2143 }
2144 
2145 /* Resend all requests through pnfs. */
2146 int pnfs_read_resend_pnfs(struct nfs_pgio_header *hdr)
2147 {
2148         struct nfs_pageio_descriptor pgio;
2149 
2150         nfs_pageio_init_read(&pgio, hdr->inode, false, hdr->completion_ops);
2151         return nfs_pageio_resend(&pgio, hdr);
2152 }
2153 EXPORT_SYMBOL_GPL(pnfs_read_resend_pnfs);
2154 
2155 static void
2156 pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
2157 {
2158         const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
2159         struct pnfs_layout_segment *lseg = desc->pg_lseg;
2160         enum pnfs_try_status trypnfs;
2161         int err = 0;
2162 
2163         trypnfs = pnfs_try_to_read_data(hdr, call_ops, lseg);
2164         if (trypnfs == PNFS_TRY_AGAIN)
2165                 err = pnfs_read_resend_pnfs(hdr);
2166         if (trypnfs == PNFS_NOT_ATTEMPTED || err)
2167                 pnfs_read_through_mds(desc, hdr);
2168 }
2169 
2170 static void pnfs_readhdr_free(struct nfs_pgio_header *hdr)
2171 {
2172         pnfs_put_lseg(hdr->lseg);
2173         nfs_pgio_header_free(hdr);
2174 }
2175 
2176 int
2177 pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
2178 {
2179         struct nfs_pgio_header *hdr;
2180         int ret;
2181 
2182         hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
2183         if (!hdr) {
2184                 desc->pg_error = -ENOMEM;
2185                 return desc->pg_error;
2186         }
2187         nfs_pgheader_init(desc, hdr, pnfs_readhdr_free);
2188         hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
2189         ret = nfs_generic_pgio(desc, hdr);
2190         if (!ret)
2191                 pnfs_do_read(desc, hdr);
2192         return ret;
2193 }
2194 EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
2195 
2196 static void pnfs_clear_layoutcommitting(struct inode *inode)
2197 {
2198         unsigned long *bitlock = &NFS_I(inode)->flags;
2199 
2200         clear_bit_unlock(NFS_INO_LAYOUTCOMMITTING, bitlock);
2201         smp_mb__after_atomic();
2202         wake_up_bit(bitlock, NFS_INO_LAYOUTCOMMITTING);
2203 }
2204 
2205 /*
2206  * There can be multiple RW segments.
2207  */
2208 static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp)
2209 {
2210         struct pnfs_layout_segment *lseg;
2211 
2212         list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
2213                 if (lseg->pls_range.iomode == IOMODE_RW &&
2214                     test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
2215                         list_add(&lseg->pls_lc_list, listp);
2216         }
2217 }
2218 
2219 static void pnfs_list_write_lseg_done(struct inode *inode, struct list_head *listp)
2220 {
2221         struct pnfs_layout_segment *lseg, *tmp;
2222 
2223         /* Matched by references in pnfs_set_layoutcommit */
2224         list_for_each_entry_safe(lseg, tmp, listp, pls_lc_list) {
2225                 list_del_init(&lseg->pls_lc_list);
2226                 pnfs_put_lseg(lseg);
2227         }
2228 
2229         pnfs_clear_layoutcommitting(inode);
2230 }
2231 
2232 void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg)
2233 {
2234         pnfs_layout_io_set_failed(lseg->pls_layout, lseg->pls_range.iomode);
2235 }
2236 EXPORT_SYMBOL_GPL(pnfs_set_lo_fail);
2237 
2238 void
2239 pnfs_set_layoutcommit(struct inode *inode, struct pnfs_layout_segment *lseg,
2240                 loff_t end_pos)
2241 {
2242         struct nfs_inode *nfsi = NFS_I(inode);
2243         bool mark_as_dirty = false;
2244 
2245         spin_lock(&inode->i_lock);
2246         if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
2247                 nfsi->layout->plh_lwb = end_pos;
2248                 mark_as_dirty = true;
2249                 dprintk("%s: Set layoutcommit for inode %lu ",
2250                         __func__, inode->i_ino);
2251         } else if (end_pos > nfsi->layout->plh_lwb)
2252                 nfsi->layout->plh_lwb = end_pos;
2253         if (!test_and_set_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags)) {
2254                 /* references matched in nfs4_layoutcommit_release */
2255                 pnfs_get_lseg(lseg);
2256         }
2257         spin_unlock(&inode->i_lock);
2258         dprintk("%s: lseg %p end_pos %llu\n",
2259                 __func__, lseg, nfsi->layout->plh_lwb);
2260 
2261         /* if pnfs_layoutcommit_inode() runs between inode locks, the next one
2262          * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
2263         if (mark_as_dirty)
2264                 mark_inode_dirty_sync(inode);
2265 }
2266 EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);
2267 
2268 void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data)
2269 {
2270         struct nfs_server *nfss = NFS_SERVER(data->args.inode);
2271 
2272         if (nfss->pnfs_curr_ld->cleanup_layoutcommit)
2273                 nfss->pnfs_curr_ld->cleanup_layoutcommit(data);
2274         pnfs_list_write_lseg_done(data->args.inode, &data->lseg_list);
2275 }
2276 
2277 /*
2278  * For the LAYOUT4_NFSV4_1_FILES layout type, NFS_DATA_SYNC WRITEs and
2279  * NFS_UNSTABLE WRITEs with a COMMIT to data servers must store enough
2280  * data to disk to allow the server to recover the data if it crashes.
2281  * LAYOUTCOMMIT is only needed when the NFL4_UFLG_COMMIT_THRU_MDS flag
2282  * is off, and a COMMIT is sent to a data server, or
2283  * if WRITEs to a data server return NFS_DATA_SYNC.
2284  */
2285 int
2286 pnfs_layoutcommit_inode(struct inode *inode, bool sync)
2287 {
2288         struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
2289         struct nfs4_layoutcommit_data *data;
2290         struct nfs_inode *nfsi = NFS_I(inode);
2291         loff_t end_pos;
2292         int status;
2293 
2294         if (!pnfs_layoutcommit_outstanding(inode))
2295                 return 0;
2296 
2297         dprintk("--> %s inode %lu\n", __func__, inode->i_ino);
2298 
2299         status = -EAGAIN;
2300         if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
2301                 if (!sync)
2302                         goto out;
2303                 status = wait_on_bit_lock_action(&nfsi->flags,
2304                                 NFS_INO_LAYOUTCOMMITTING,
2305                                 nfs_wait_bit_killable,
2306                                 TASK_KILLABLE);
2307                 if (status)
2308                         goto out;
2309         }
2310 
2311         status = -ENOMEM;
2312         /* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
2313         data = kzalloc(sizeof(*data), GFP_NOFS);
2314         if (!data)
2315                 goto clear_layoutcommitting;
2316 
2317         status = 0;
2318         spin_lock(&inode->i_lock);
2319         if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
2320                 goto out_unlock;
2321 
2322         INIT_LIST_HEAD(&data->lseg_list);
2323         pnfs_list_write_lseg(inode, &data->lseg_list);
2324 
2325         end_pos = nfsi->layout->plh_lwb;
2326 
2327         nfs4_stateid_copy(&data->args.stateid, &nfsi->layout->plh_stateid);
2328         spin_unlock(&inode->i_lock);
2329 
2330         data->args.inode = inode;
2331         data->cred = get_rpccred(nfsi->layout->plh_lc_cred);
2332         nfs_fattr_init(&data->fattr);
2333         data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
2334         data->res.fattr = &data->fattr;
2335         data->args.lastbytewritten = end_pos - 1;
2336         data->res.server = NFS_SERVER(inode);
2337 
2338         if (ld->prepare_layoutcommit) {
2339                 status = ld->prepare_layoutcommit(&data->args);
2340                 if (status) {
2341                         put_rpccred(data->cred);
2342                         spin_lock(&inode->i_lock);
2343                         set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags);
2344                         if (end_pos > nfsi->layout->plh_lwb)
2345                                 nfsi->layout->plh_lwb = end_pos;
2346                         goto out_unlock;
2347                 }
2348         }
2349 
2350 
2351         status = nfs4_proc_layoutcommit(data, sync);
2352 out:
2353         if (status)
2354                 mark_inode_dirty_sync(inode);
2355         dprintk("<-- %s status %d\n", __func__, status);
2356         return status;
2357 out_unlock:
2358         spin_unlock(&inode->i_lock);
2359         kfree(data);
2360 clear_layoutcommitting:
2361         pnfs_clear_layoutcommitting(inode);
2362         goto out;
2363 }
2364 EXPORT_SYMBOL_GPL(pnfs_layoutcommit_inode);
2365 
2366 int
2367 pnfs_generic_sync(struct inode *inode, bool datasync)
2368 {
2369         return pnfs_layoutcommit_inode(inode, true);
2370 }
2371 EXPORT_SYMBOL_GPL(pnfs_generic_sync);
2372 
2373 struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
2374 {
2375         struct nfs4_threshold *thp;
2376 
2377         thp = kzalloc(sizeof(*thp), GFP_NOFS);
2378         if (!thp) {
2379                 dprintk("%s mdsthreshold allocation failed\n", __func__);
2380                 return NULL;
2381         }
2382         return thp;
2383 }
2384 
2385 #if IS_ENABLED(CONFIG_NFS_V4_2)
2386 int
2387 pnfs_report_layoutstat(struct inode *inode, gfp_t gfp_flags)
2388 {
2389         struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
2390         struct nfs_server *server = NFS_SERVER(inode);
2391         struct nfs_inode *nfsi = NFS_I(inode);
2392         struct nfs42_layoutstat_data *data;
2393         struct pnfs_layout_hdr *hdr;
2394         int status = 0;
2395 
2396         if (!pnfs_enabled_sb(server) || !ld->prepare_layoutstats)
2397                 goto out;
2398 
2399         if (!nfs_server_capable(inode, NFS_CAP_LAYOUTSTATS))
2400                 goto out;
2401 
2402         if (test_and_set_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags))
2403                 goto out;
2404 
2405         spin_lock(&inode->i_lock);
2406         if (!NFS_I(inode)->layout) {
2407                 spin_unlock(&inode->i_lock);
2408                 goto out;
2409         }
2410         hdr = NFS_I(inode)->layout;
2411         pnfs_get_layout_hdr(hdr);
2412         spin_unlock(&inode->i_lock);
2413 
2414         data = kzalloc(sizeof(*data), gfp_flags);
2415         if (!data) {
2416                 status = -ENOMEM;
2417                 goto out_put;
2418         }
2419 
2420         data->args.fh = NFS_FH(inode);
2421         data->args.inode = inode;
2422         nfs4_stateid_copy(&data->args.stateid, &hdr->plh_stateid);
2423         status = ld->prepare_layoutstats(&data->args);
2424         if (status)
2425                 goto out_free;
2426 
2427         status = nfs42_proc_layoutstats_generic(NFS_SERVER(inode), data);
2428 
2429 out:
2430         dprintk("%s returns %d\n", __func__, status);
2431         return status;
2432 
2433 out_free:
2434         kfree(data);
2435 out_put:
2436         pnfs_put_layout_hdr(hdr);
2437         smp_mb__before_atomic();
2438         clear_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags);
2439         smp_mb__after_atomic();
2440         goto out;
2441 }
2442 EXPORT_SYMBOL_GPL(pnfs_report_layoutstat);
2443 #endif
2444 
2445 unsigned int layoutstats_timer;
2446 module_param(layoutstats_timer, uint, 0644);
2447 EXPORT_SYMBOL_GPL(layoutstats_timer);
2448 

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