root/fs/ceph/addr.c

DEFINITIONS

1. page_snap_context
2. ceph_set_page_dirty
3. ceph_invalidatepage
4. ceph_releasepage
5. ceph_do_readpage
6. ceph_readpage
7. finish_read
8. start_read
9. ceph_readpages
10. get_oldest_context
11. get_writepages_data_length
12. writepage_nounlock
13. ceph_writepage
14. writepages_finish
15. ceph_writepages_start
16. context_is_writeable_or_written
17. ceph_update_writeable_page
18. ceph_write_begin
19. ceph_write_end
20. ceph_direct_io
21. ceph_block_sigs
22. ceph_restore_sigs
23. ceph_filemap_fault
24. ceph_page_mkwrite
25. ceph_fill_inline_data
26. ceph_uninline_data
27. ceph_mmap
28. __ceph_pool_perm_get
29. ceph_pool_perm_check
30. ceph_pool_perm_destroy

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/ceph/ceph_debug.h>
   3 
   4 #include <linux/backing-dev.h>
   5 #include <linux/fs.h>
   6 #include <linux/mm.h>
   7 #include <linux/pagemap.h>
   8 #include <linux/writeback.h>    /* generic_writepages */
   9 #include <linux/slab.h>
  10 #include <linux/pagevec.h>
  11 #include <linux/task_io_accounting_ops.h>
  12 #include <linux/signal.h>
  13 #include <linux/iversion.h>
  14 
  15 #include "super.h"
  16 #include "mds_client.h"
  17 #include "cache.h"
  18 #include <linux/ceph/osd_client.h>
  19 #include <linux/ceph/striper.h>
  20 
  21 /*
  22  * Ceph address space ops.
  23  *
  24  * There are a few funny things going on here.
  25  *
  26  * The page->private field is used to reference a struct
  27  * ceph_snap_context for _every_ dirty page.  This indicates which
  28  * snapshot the page was logically dirtied in, and thus which snap
  29  * context needs to be associated with the osd write during writeback.
  30  *
  31  * Similarly, struct ceph_inode_info maintains a set of counters to
  32  * count dirty pages on the inode.  In the absence of snapshots,
  33  * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
  34  *
  35  * When a snapshot is taken (that is, when the client receives
  36  * notification that a snapshot was taken), each inode with caps and
  37  * with dirty pages (dirty pages implies there is a cap) gets a new
  38  * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
  39  * order, new snaps go to the tail).  The i_wrbuffer_ref_head count is
  40  * moved to capsnap->dirty. (Unless a sync write is currently in
  41  * progress.  In that case, the capsnap is said to be "pending", new
  42  * writes cannot start, and the capsnap isn't "finalized" until the
  43  * write completes (or fails) and a final size/mtime for the inode for
  44  * that snap can be settled upon.)  i_wrbuffer_ref_head is reset to 0.
  45  *
  46  * On writeback, we must submit writes to the osd IN SNAP ORDER.  So,
  47  * we look for the first capsnap in i_cap_snaps and write out pages in
  48  * that snap context _only_.  Then we move on to the next capsnap,
  49  * eventually reaching the "live" or "head" context (i.e., pages that
  50  * are not yet snapped) and are writing the most recently dirtied
  51  * pages.
  52  *
  53  * Invalidate and so forth must take care to ensure the dirty page
  54  * accounting is preserved.
  55  */
  56 
  57 #define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
  58 #define CONGESTION_OFF_THRESH(congestion_kb)                            \
  59         (CONGESTION_ON_THRESH(congestion_kb) -                          \
  60          (CONGESTION_ON_THRESH(congestion_kb) >> 2))
  61 
  62 static inline struct ceph_snap_context *page_snap_context(struct page *page)
  63 {
  64         if (PagePrivate(page))
  65                 return (void *)page->private;
  66         return NULL;
  67 }
  68 
  69 /*
  70  * Dirty a page.  Optimistically adjust accounting, on the assumption
  71  * that we won't race with invalidate.  If we do, readjust.
  72  */
  73 static int ceph_set_page_dirty(struct page *page)
  74 {
  75         struct address_space *mapping = page->mapping;
  76         struct inode *inode;
  77         struct ceph_inode_info *ci;
  78         struct ceph_snap_context *snapc;
  79         int ret;
  80 
  81         if (unlikely(!mapping))
  82                 return !TestSetPageDirty(page);
  83 
  84         if (PageDirty(page)) {
  85                 dout("%p set_page_dirty %p idx %lu -- already dirty\n",
  86                      mapping->host, page, page->index);
  87                 BUG_ON(!PagePrivate(page));
  88                 return 0;
  89         }
  90 
  91         inode = mapping->host;
  92         ci = ceph_inode(inode);
  93 
  94         /* dirty the head */
  95         spin_lock(&ci->i_ceph_lock);
  96         BUG_ON(ci->i_wr_ref == 0); // caller should hold Fw reference
  97         if (__ceph_have_pending_cap_snap(ci)) {
  98                 struct ceph_cap_snap *capsnap =
  99                                 list_last_entry(&ci->i_cap_snaps,
 100                                                 struct ceph_cap_snap,
 101                                                 ci_item);
 102                 snapc = ceph_get_snap_context(capsnap->context);
 103                 capsnap->dirty_pages++;
 104         } else {
 105                 BUG_ON(!ci->i_head_snapc);
 106                 snapc = ceph_get_snap_context(ci->i_head_snapc);
 107                 ++ci->i_wrbuffer_ref_head;
 108         }
 109         if (ci->i_wrbuffer_ref == 0)
 110                 ihold(inode);
 111         ++ci->i_wrbuffer_ref;
 112         dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
 113              "snapc %p seq %lld (%d snaps)\n",
 114              mapping->host, page, page->index,
 115              ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
 116              ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
 117              snapc, snapc->seq, snapc->num_snaps);
 118         spin_unlock(&ci->i_ceph_lock);
 119 
 120         /*
 121          * Reference snap context in page->private.  Also set
 122          * PagePrivate so that we get invalidatepage callback.
 123          */
 124         BUG_ON(PagePrivate(page));
 125         page->private = (unsigned long)snapc;
 126         SetPagePrivate(page);
 127 
 128         ret = __set_page_dirty_nobuffers(page);
 129         WARN_ON(!PageLocked(page));
 130         WARN_ON(!page->mapping);
 131 
 132         return ret;
 133 }
 134 
 135 /*
 136  * If we are truncating the full page (i.e. offset == 0), adjust the
 137  * dirty page counters appropriately.  Only called if there is private
 138  * data on the page.
 139  */
 140 static void ceph_invalidatepage(struct page *page, unsigned int offset,
 141                                 unsigned int length)
 142 {
 143         struct inode *inode;
 144         struct ceph_inode_info *ci;
 145         struct ceph_snap_context *snapc = page_snap_context(page);
 146 
 147         inode = page->mapping->host;
 148         ci = ceph_inode(inode);
 149 
 150         if (offset != 0 || length != PAGE_SIZE) {
 151                 dout("%p invalidatepage %p idx %lu partial dirty page %u~%u\n",
 152                      inode, page, page->index, offset, length);
 153                 return;
 154         }
 155 
 156         ceph_invalidate_fscache_page(inode, page);
 157 
 158         WARN_ON(!PageLocked(page));
 159         if (!PagePrivate(page))
 160                 return;
 161 
 162         ClearPageChecked(page);
 163 
 164         dout("%p invalidatepage %p idx %lu full dirty page\n",
 165              inode, page, page->index);
 166 
 167         ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
 168         ceph_put_snap_context(snapc);
 169         page->private = 0;
 170         ClearPagePrivate(page);
 171 }
 172 
 173 static int ceph_releasepage(struct page *page, gfp_t g)
 174 {
 175         dout("%p releasepage %p idx %lu (%sdirty)\n", page->mapping->host,
 176              page, page->index, PageDirty(page) ? "" : "not ");
 177 
 178         /* Can we release the page from the cache? */
 179         if (!ceph_release_fscache_page(page, g))
 180                 return 0;
 181 
 182         return !PagePrivate(page);
 183 }
 184 
 185 /*
 186  * read a single page, without unlocking it.
 187  */
 188 static int ceph_do_readpage(struct file *filp, struct page *page)
 189 {
 190         struct inode *inode = file_inode(filp);
 191         struct ceph_inode_info *ci = ceph_inode(inode);
 192         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 193         int err = 0;
 194         u64 off = page_offset(page);
 195         u64 len = PAGE_SIZE;
 196 
 197         if (off >= i_size_read(inode)) {
 198                 zero_user_segment(page, 0, PAGE_SIZE);
 199                 SetPageUptodate(page);
 200                 return 0;
 201         }
 202 
 203         if (ci->i_inline_version != CEPH_INLINE_NONE) {
 204                 /*
 205                  * Uptodate inline data should have been added
 206                  * into page cache while getting Fcr caps.
 207                  */
 208                 if (off == 0)
 209                         return -EINVAL;
 210                 zero_user_segment(page, 0, PAGE_SIZE);
 211                 SetPageUptodate(page);
 212                 return 0;
 213         }
 214 
 215         err = ceph_readpage_from_fscache(inode, page);
 216         if (err == 0)
 217                 return -EINPROGRESS;
 218 
 219         dout("readpage inode %p file %p page %p index %lu\n",
 220              inode, filp, page, page->index);
 221         err = ceph_osdc_readpages(&fsc->client->osdc, ceph_vino(inode),
 222                                   &ci->i_layout, off, &len,
 223                                   ci->i_truncate_seq, ci->i_truncate_size,
 224                                   &page, 1, 0);
 225         if (err == -ENOENT)
 226                 err = 0;
 227         if (err < 0) {
 228                 SetPageError(page);
 229                 ceph_fscache_readpage_cancel(inode, page);
 230                 if (err == -EBLACKLISTED)
 231                         fsc->blacklisted = true;
 232                 goto out;
 233         }
 234         if (err < PAGE_SIZE)
 235                 /* zero fill remainder of page */
 236                 zero_user_segment(page, err, PAGE_SIZE);
 237         else
 238                 flush_dcache_page(page);
 239 
 240         SetPageUptodate(page);
 241         ceph_readpage_to_fscache(inode, page);
 242 
 243 out:
 244         return err < 0 ? err : 0;
 245 }
 246 
 247 static int ceph_readpage(struct file *filp, struct page *page)
 248 {
 249         int r = ceph_do_readpage(filp, page);
 250         if (r != -EINPROGRESS)
 251                 unlock_page(page);
 252         else
 253                 r = 0;
 254         return r;
 255 }
 256 
 257 /*
 258  * Finish an async read(ahead) op.
 259  */
 260 static void finish_read(struct ceph_osd_request *req)
 261 {
 262         struct inode *inode = req->r_inode;
 263         struct ceph_osd_data *osd_data;
 264         int rc = req->r_result <= 0 ? req->r_result : 0;
 265         int bytes = req->r_result >= 0 ? req->r_result : 0;
 266         int num_pages;
 267         int i;
 268 
 269         dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
 270         if (rc == -EBLACKLISTED)
 271                 ceph_inode_to_client(inode)->blacklisted = true;
 272 
 273         /* unlock all pages, zeroing any data we didn't read */
 274         osd_data = osd_req_op_extent_osd_data(req, 0);
 275         BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
 276         num_pages = calc_pages_for((u64)osd_data->alignment,
 277                                         (u64)osd_data->length);
 278         for (i = 0; i < num_pages; i++) {
 279                 struct page *page = osd_data->pages[i];
 280 
 281                 if (rc < 0 && rc != -ENOENT) {
 282                         ceph_fscache_readpage_cancel(inode, page);
 283                         goto unlock;
 284                 }
 285                 if (bytes < (int)PAGE_SIZE) {
 286                         /* zero (remainder of) page */
 287                         int s = bytes < 0 ? 0 : bytes;
 288                         zero_user_segment(page, s, PAGE_SIZE);
 289                 }
 290                 dout("finish_read %p uptodate %p idx %lu\n", inode, page,
 291                      page->index);
 292                 flush_dcache_page(page);
 293                 SetPageUptodate(page);
 294                 ceph_readpage_to_fscache(inode, page);
 295 unlock:
 296                 unlock_page(page);
 297                 put_page(page);
 298                 bytes -= PAGE_SIZE;
 299         }
 300         kfree(osd_data->pages);
 301 }
 302 
 303 /*
 304  * start an async read(ahead) operation.  return nr_pages we submitted
 305  * a read for on success, or negative error code.
 306  */
 307 static int start_read(struct inode *inode, struct ceph_rw_context *rw_ctx,
 308                       struct list_head *page_list, int max)
 309 {
 310         struct ceph_osd_client *osdc =
 311                 &ceph_inode_to_client(inode)->client->osdc;
 312         struct ceph_inode_info *ci = ceph_inode(inode);
 313         struct page *page = lru_to_page(page_list);
 314         struct ceph_vino vino;
 315         struct ceph_osd_request *req;
 316         u64 off;
 317         u64 len;
 318         int i;
 319         struct page **pages;
 320         pgoff_t next_index;
 321         int nr_pages = 0;
 322         int got = 0;
 323         int ret = 0;
 324 
 325         if (!rw_ctx) {
 326                 /* caller of readpages does not hold buffer and read caps
 327                  * (fadvise, madvise and readahead cases) */
 328                 int want = CEPH_CAP_FILE_CACHE;
 329                 ret = ceph_try_get_caps(inode, CEPH_CAP_FILE_RD, want,
 330                                         true, &got);
 331                 if (ret < 0) {
 332                         dout("start_read %p, error getting cap\n", inode);
 333                 } else if (!(got & want)) {
 334                         dout("start_read %p, no cache cap\n", inode);
 335                         ret = 0;
 336                 }
 337                 if (ret <= 0) {
 338                         if (got)
 339                                 ceph_put_cap_refs(ci, got);
 340                         while (!list_empty(page_list)) {
 341                                 page = lru_to_page(page_list);
 342                                 list_del(&page->lru);
 343                                 put_page(page);
 344                         }
 345                         return ret;
 346                 }
 347         }
 348 
 349         off = (u64) page_offset(page);
 350 
 351         /* count pages */
 352         next_index = page->index;
 353         list_for_each_entry_reverse(page, page_list, lru) {
 354                 if (page->index != next_index)
 355                         break;
 356                 nr_pages++;
 357                 next_index++;
 358                 if (max && nr_pages == max)
 359                         break;
 360         }
 361         len = nr_pages << PAGE_SHIFT;
 362         dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
 363              off, len);
 364         vino = ceph_vino(inode);
 365         req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len,
 366                                     0, 1, CEPH_OSD_OP_READ,
 367                                     CEPH_OSD_FLAG_READ, NULL,
 368                                     ci->i_truncate_seq, ci->i_truncate_size,
 369                                     false);
 370         if (IS_ERR(req)) {
 371                 ret = PTR_ERR(req);
 372                 goto out;
 373         }
 374 
 375         /* build page vector */
 376         nr_pages = calc_pages_for(0, len);
 377         pages = kmalloc_array(nr_pages, sizeof(*pages), GFP_KERNEL);
 378         if (!pages) {
 379                 ret = -ENOMEM;
 380                 goto out_put;
 381         }
 382         for (i = 0; i < nr_pages; ++i) {
 383                 page = list_entry(page_list->prev, struct page, lru);
 384                 BUG_ON(PageLocked(page));
 385                 list_del(&page->lru);
 386 
 387                 dout("start_read %p adding %p idx %lu\n", inode, page,
 388                      page->index);
 389                 if (add_to_page_cache_lru(page, &inode->i_data, page->index,
 390                                           GFP_KERNEL)) {
 391                         ceph_fscache_uncache_page(inode, page);
 392                         put_page(page);
 393                         dout("start_read %p add_to_page_cache failed %p\n",
 394                              inode, page);
 395                         nr_pages = i;
 396                         if (nr_pages > 0) {
 397                                 len = nr_pages << PAGE_SHIFT;
 398                                 osd_req_op_extent_update(req, 0, len);
 399                                 break;
 400                         }
 401                         goto out_pages;
 402                 }
 403                 pages[i] = page;
 404         }
 405         osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false);
 406         req->r_callback = finish_read;
 407         req->r_inode = inode;
 408 
 409         dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
 410         ret = ceph_osdc_start_request(osdc, req, false);
 411         if (ret < 0)
 412                 goto out_pages;
 413         ceph_osdc_put_request(req);
 414 
 415         /* After adding locked pages to page cache, the inode holds cache cap.
 416          * So we can drop our cap refs. */
 417         if (got)
 418                 ceph_put_cap_refs(ci, got);
 419 
 420         return nr_pages;
 421 
 422 out_pages:
 423         for (i = 0; i < nr_pages; ++i) {
 424                 ceph_fscache_readpage_cancel(inode, pages[i]);
 425                 unlock_page(pages[i]);
 426         }
 427         ceph_put_page_vector(pages, nr_pages, false);
 428 out_put:
 429         ceph_osdc_put_request(req);
 430 out:
 431         if (got)
 432                 ceph_put_cap_refs(ci, got);
 433         return ret;
 434 }
 435 
 436 
 437 /*
 438  * Read multiple pages.  Leave pages we don't read + unlock in page_list;
 439  * the caller (VM) cleans them up.
 440  */
 441 static int ceph_readpages(struct file *file, struct address_space *mapping,
 442                           struct list_head *page_list, unsigned nr_pages)
 443 {
 444         struct inode *inode = file_inode(file);
 445         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 446         struct ceph_file_info *fi = file->private_data;
 447         struct ceph_rw_context *rw_ctx;
 448         int rc = 0;
 449         int max = 0;
 450 
 451         if (ceph_inode(inode)->i_inline_version != CEPH_INLINE_NONE)
 452                 return -EINVAL;
 453 
 454         rc = ceph_readpages_from_fscache(mapping->host, mapping, page_list,
 455                                          &nr_pages);
 456 
 457         if (rc == 0)
 458                 goto out;
 459 
 460         rw_ctx = ceph_find_rw_context(fi);
 461         max = fsc->mount_options->rsize >> PAGE_SHIFT;
 462         dout("readpages %p file %p ctx %p nr_pages %d max %d\n",
 463              inode, file, rw_ctx, nr_pages, max);
 464         while (!list_empty(page_list)) {
 465                 rc = start_read(inode, rw_ctx, page_list, max);
 466                 if (rc < 0)
 467                         goto out;
 468         }
 469 out:
 470         ceph_fscache_readpages_cancel(inode, page_list);
 471 
 472         dout("readpages %p file %p ret %d\n", inode, file, rc);
 473         return rc;
 474 }
 475 
 476 struct ceph_writeback_ctl
 477 {
 478         loff_t i_size;
 479         u64 truncate_size;
 480         u32 truncate_seq;
 481         bool size_stable;
 482         bool head_snapc;
 483 };
 484 
 485 /*
 486  * Get ref for the oldest snapc for an inode with dirty data... that is, the
 487  * only snap context we are allowed to write back.
 488  */
 489 static struct ceph_snap_context *
 490 get_oldest_context(struct inode *inode, struct ceph_writeback_ctl *ctl,
 491                    struct ceph_snap_context *page_snapc)
 492 {
 493         struct ceph_inode_info *ci = ceph_inode(inode);
 494         struct ceph_snap_context *snapc = NULL;
 495         struct ceph_cap_snap *capsnap = NULL;
 496 
 497         spin_lock(&ci->i_ceph_lock);
 498         list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
 499                 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
 500                      capsnap->context, capsnap->dirty_pages);
 501                 if (!capsnap->dirty_pages)
 502                         continue;
 503 
 504                 /* get i_size, truncate_{seq,size} for page_snapc? */
 505                 if (snapc && capsnap->context != page_snapc)
 506                         continue;
 507 
 508                 if (ctl) {
 509                         if (capsnap->writing) {
 510                                 ctl->i_size = i_size_read(inode);
 511                                 ctl->size_stable = false;
 512                         } else {
 513                                 ctl->i_size = capsnap->size;
 514                                 ctl->size_stable = true;
 515                         }
 516                         ctl->truncate_size = capsnap->truncate_size;
 517                         ctl->truncate_seq = capsnap->truncate_seq;
 518                         ctl->head_snapc = false;
 519                 }
 520 
 521                 if (snapc)
 522                         break;
 523 
 524                 snapc = ceph_get_snap_context(capsnap->context);
 525                 if (!page_snapc ||
 526                     page_snapc == snapc ||
 527                     page_snapc->seq > snapc->seq)
 528                         break;
 529         }
 530         if (!snapc && ci->i_wrbuffer_ref_head) {
 531                 snapc = ceph_get_snap_context(ci->i_head_snapc);
 532                 dout(" head snapc %p has %d dirty pages\n",
 533                      snapc, ci->i_wrbuffer_ref_head);
 534                 if (ctl) {
 535                         ctl->i_size = i_size_read(inode);
 536                         ctl->truncate_size = ci->i_truncate_size;
 537                         ctl->truncate_seq = ci->i_truncate_seq;
 538                         ctl->size_stable = false;
 539                         ctl->head_snapc = true;
 540                 }
 541         }
 542         spin_unlock(&ci->i_ceph_lock);
 543         return snapc;
 544 }
 545 
 546 static u64 get_writepages_data_length(struct inode *inode,
 547                                       struct page *page, u64 start)
 548 {
 549         struct ceph_inode_info *ci = ceph_inode(inode);
 550         struct ceph_snap_context *snapc = page_snap_context(page);
 551         struct ceph_cap_snap *capsnap = NULL;
 552         u64 end = i_size_read(inode);
 553 
 554         if (snapc != ci->i_head_snapc) {
 555                 bool found = false;
 556                 spin_lock(&ci->i_ceph_lock);
 557                 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
 558                         if (capsnap->context == snapc) {
 559                                 if (!capsnap->writing)
 560                                         end = capsnap->size;
 561                                 found = true;
 562                                 break;
 563                         }
 564                 }
 565                 spin_unlock(&ci->i_ceph_lock);
 566                 WARN_ON(!found);
 567         }
 568         if (end > page_offset(page) + PAGE_SIZE)
 569                 end = page_offset(page) + PAGE_SIZE;
 570         return end > start ? end - start : 0;
 571 }
 572 
 573 /*
 574  * Write a single page, but leave the page locked.
 575  *
 576  * If we get a write error, mark the mapping for error, but still adjust the
 577  * dirty page accounting (i.e., page is no longer dirty).
 578  */
 579 static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 580 {
 581         struct inode *inode;
 582         struct ceph_inode_info *ci;
 583         struct ceph_fs_client *fsc;
 584         struct ceph_snap_context *snapc, *oldest;
 585         loff_t page_off = page_offset(page);
 586         int err, len = PAGE_SIZE;
 587         struct ceph_writeback_ctl ceph_wbc;
 588 
 589         dout("writepage %p idx %lu\n", page, page->index);
 590 
 591         inode = page->mapping->host;
 592         ci = ceph_inode(inode);
 593         fsc = ceph_inode_to_client(inode);
 594 
 595         /* verify this is a writeable snap context */
 596         snapc = page_snap_context(page);
 597         if (!snapc) {
 598                 dout("writepage %p page %p not dirty?\n", inode, page);
 599                 return 0;
 600         }
 601         oldest = get_oldest_context(inode, &ceph_wbc, snapc);
 602         if (snapc->seq > oldest->seq) {
 603                 dout("writepage %p page %p snapc %p not writeable - noop\n",
 604                      inode, page, snapc);
 605                 /* we should only noop if called by kswapd */
 606                 WARN_ON(!(current->flags & PF_MEMALLOC));
 607                 ceph_put_snap_context(oldest);
 608                 redirty_page_for_writepage(wbc, page);
 609                 return 0;
 610         }
 611         ceph_put_snap_context(oldest);
 612 
 613         /* is this a partial page at end of file? */
 614         if (page_off >= ceph_wbc.i_size) {
 615                 dout("%p page eof %llu\n", page, ceph_wbc.i_size);
 616                 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
 617                 return 0;
 618         }
 619 
 620         if (ceph_wbc.i_size < page_off + len)
 621                 len = ceph_wbc.i_size - page_off;
 622 
 623         dout("writepage %p page %p index %lu on %llu~%u snapc %p seq %lld\n",
 624              inode, page, page->index, page_off, len, snapc, snapc->seq);
 625 
 626         if (atomic_long_inc_return(&fsc->writeback_count) >
 627             CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
 628                 set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 629 
 630         set_page_writeback(page);
 631         err = ceph_osdc_writepages(&fsc->client->osdc, ceph_vino(inode),
 632                                    &ci->i_layout, snapc, page_off, len,
 633                                    ceph_wbc.truncate_seq,
 634                                    ceph_wbc.truncate_size,
 635                                    &inode->i_mtime, &page, 1);
 636         if (err < 0) {
 637                 struct writeback_control tmp_wbc;
 638                 if (!wbc)
 639                         wbc = &tmp_wbc;
 640                 if (err == -ERESTARTSYS) {
 641                         /* killed by SIGKILL */
 642                         dout("writepage interrupted page %p\n", page);
 643                         redirty_page_for_writepage(wbc, page);
 644                         end_page_writeback(page);
 645                         return err;
 646                 }
 647                 if (err == -EBLACKLISTED)
 648                         fsc->blacklisted = true;
 649                 dout("writepage setting page/mapping error %d %p\n",
 650                      err, page);
 651                 mapping_set_error(&inode->i_data, err);
 652                 wbc->pages_skipped++;
 653         } else {
 654                 dout("writepage cleaned page %p\n", page);
 655                 err = 0;  /* vfs expects us to return 0 */
 656         }
 657         page->private = 0;
 658         ClearPagePrivate(page);
 659         end_page_writeback(page);
 660         ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
 661         ceph_put_snap_context(snapc);  /* page's reference */
 662 
 663         if (atomic_long_dec_return(&fsc->writeback_count) <
 664             CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
 665                 clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 666 
 667         return err;
 668 }
 669 
 670 static int ceph_writepage(struct page *page, struct writeback_control *wbc)
 671 {
 672         int err;
 673         struct inode *inode = page->mapping->host;
 674         BUG_ON(!inode);
 675         ihold(inode);
 676         err = writepage_nounlock(page, wbc);
 677         if (err == -ERESTARTSYS) {
 678                 /* direct memory reclaimer was killed by SIGKILL. return 0
 679                  * to prevent caller from setting mapping/page error */
 680                 err = 0;
 681         }
 682         unlock_page(page);
 683         iput(inode);
 684         return err;
 685 }
 686 
 687 /*
 688  * async writeback completion handler.
 689  *
 690  * If we get an error, set the mapping error bit, but not the individual
 691  * page error bits.
 692  */
 693 static void writepages_finish(struct ceph_osd_request *req)
 694 {
 695         struct inode *inode = req->r_inode;
 696         struct ceph_inode_info *ci = ceph_inode(inode);
 697         struct ceph_osd_data *osd_data;
 698         struct page *page;
 699         int num_pages, total_pages = 0;
 700         int i, j;
 701         int rc = req->r_result;
 702         struct ceph_snap_context *snapc = req->r_snapc;
 703         struct address_space *mapping = inode->i_mapping;
 704         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 705         bool remove_page;
 706 
 707         dout("writepages_finish %p rc %d\n", inode, rc);
 708         if (rc < 0) {
 709                 mapping_set_error(mapping, rc);
 710                 ceph_set_error_write(ci);
 711                 if (rc == -EBLACKLISTED)
 712                         fsc->blacklisted = true;
 713         } else {
 714                 ceph_clear_error_write(ci);
 715         }
 716 
 717         /*
 718          * We lost the cache cap, need to truncate the page before
 719          * it is unlocked, otherwise we'd truncate it later in the
 720          * page truncation thread, possibly losing some data that
 721          * raced its way in
 722          */
 723         remove_page = !(ceph_caps_issued(ci) &
 724                         (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO));
 725 
 726         /* clean all pages */
 727         for (i = 0; i < req->r_num_ops; i++) {
 728                 if (req->r_ops[i].op != CEPH_OSD_OP_WRITE)
 729                         break;
 730 
 731                 osd_data = osd_req_op_extent_osd_data(req, i);
 732                 BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
 733                 num_pages = calc_pages_for((u64)osd_data->alignment,
 734                                            (u64)osd_data->length);
 735                 total_pages += num_pages;
 736                 for (j = 0; j < num_pages; j++) {
 737                         page = osd_data->pages[j];
 738                         BUG_ON(!page);
 739                         WARN_ON(!PageUptodate(page));
 740 
 741                         if (atomic_long_dec_return(&fsc->writeback_count) <
 742                              CONGESTION_OFF_THRESH(
 743                                         fsc->mount_options->congestion_kb))
 744                                 clear_bdi_congested(inode_to_bdi(inode),
 745                                                     BLK_RW_ASYNC);
 746 
 747                         ceph_put_snap_context(page_snap_context(page));
 748                         page->private = 0;
 749                         ClearPagePrivate(page);
 750                         dout("unlocking %p\n", page);
 751                         end_page_writeback(page);
 752 
 753                         if (remove_page)
 754                                 generic_error_remove_page(inode->i_mapping,
 755                                                           page);
 756 
 757                         unlock_page(page);
 758                 }
 759                 dout("writepages_finish %p wrote %llu bytes cleaned %d pages\n",
 760                      inode, osd_data->length, rc >= 0 ? num_pages : 0);
 761 
 762                 release_pages(osd_data->pages, num_pages);
 763         }
 764 
 765         ceph_put_wrbuffer_cap_refs(ci, total_pages, snapc);
 766 
 767         osd_data = osd_req_op_extent_osd_data(req, 0);
 768         if (osd_data->pages_from_pool)
 769                 mempool_free(osd_data->pages,
 770                              ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool);
 771         else
 772                 kfree(osd_data->pages);
 773         ceph_osdc_put_request(req);
 774 }
 775 
 776 /*
 777  * initiate async writeback
 778  */
 779 static int ceph_writepages_start(struct address_space *mapping,
 780                                  struct writeback_control *wbc)
 781 {
 782         struct inode *inode = mapping->host;
 783         struct ceph_inode_info *ci = ceph_inode(inode);
 784         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 785         struct ceph_vino vino = ceph_vino(inode);
 786         pgoff_t index, start_index, end = -1;
 787         struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
 788         struct pagevec pvec;
 789         int rc = 0;
 790         unsigned int wsize = i_blocksize(inode);
 791         struct ceph_osd_request *req = NULL;
 792         struct ceph_writeback_ctl ceph_wbc;
 793         bool should_loop, range_whole = false;
 794         bool done = false;
 795 
 796         dout("writepages_start %p (mode=%s)\n", inode,
 797              wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
 798              (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
 799 
 800         if (READ_ONCE(fsc->mount_state) == CEPH_MOUNT_SHUTDOWN) {
 801                 if (ci->i_wrbuffer_ref > 0) {
 802                         pr_warn_ratelimited(
 803                                 "writepage_start %p %lld forced umount\n",
 804                                 inode, ceph_ino(inode));
 805                 }
 806                 mapping_set_error(mapping, -EIO);
 807                 return -EIO; /* we're in a forced umount, don't write! */
 808         }
 809         if (fsc->mount_options->wsize < wsize)
 810                 wsize = fsc->mount_options->wsize;
 811 
 812         pagevec_init(&pvec);
 813 
 814         start_index = wbc->range_cyclic ? mapping->writeback_index : 0;
 815         index = start_index;
 816 
 817 retry:
 818         /* find oldest snap context with dirty data */
 819         snapc = get_oldest_context(inode, &ceph_wbc, NULL);
 820         if (!snapc) {
 821                 /* hmm, why does writepages get called when there
 822                    is no dirty data? */
 823                 dout(" no snap context with dirty data?\n");
 824                 goto out;
 825         }
 826         dout(" oldest snapc is %p seq %lld (%d snaps)\n",
 827              snapc, snapc->seq, snapc->num_snaps);
 828 
 829         should_loop = false;
 830         if (ceph_wbc.head_snapc && snapc != last_snapc) {
 831                 /* where to start/end? */
 832                 if (wbc->range_cyclic) {
 833                         index = start_index;
 834                         end = -1;
 835                         if (index > 0)
 836                                 should_loop = true;
 837                         dout(" cyclic, start at %lu\n", index);
 838                 } else {
 839                         index = wbc->range_start >> PAGE_SHIFT;
 840                         end = wbc->range_end >> PAGE_SHIFT;
 841                         if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 842                                 range_whole = true;
 843                         dout(" not cyclic, %lu to %lu\n", index, end);
 844                 }
 845         } else if (!ceph_wbc.head_snapc) {
 846                 /* Do not respect wbc->range_{start,end}. Dirty pages
 847                  * in that range can be associated with newer snapc.
 848                  * They are not writeable until we write all dirty pages
 849                  * associated with 'snapc' get written */
 850                 if (index > 0)
 851                         should_loop = true;
 852                 dout(" non-head snapc, range whole\n");
 853         }
 854 
 855         ceph_put_snap_context(last_snapc);
 856         last_snapc = snapc;
 857 
 858         while (!done && index <= end) {
 859                 int num_ops = 0, op_idx;
 860                 unsigned i, pvec_pages, max_pages, locked_pages = 0;
 861                 struct page **pages = NULL, **data_pages;
 862                 mempool_t *pool = NULL; /* Becomes non-null if mempool used */
 863                 struct page *page;
 864                 pgoff_t strip_unit_end = 0;
 865                 u64 offset = 0, len = 0;
 866 
 867                 max_pages = wsize >> PAGE_SHIFT;
 868 
 869 get_more_pages:
 870                 pvec_pages = pagevec_lookup_range_nr_tag(&pvec, mapping, &index,
 871                                                 end, PAGECACHE_TAG_DIRTY,
 872                                                 max_pages - locked_pages);
 873                 dout("pagevec_lookup_range_tag got %d\n", pvec_pages);
 874                 if (!pvec_pages && !locked_pages)
 875                         break;
 876                 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
 877                         page = pvec.pages[i];
 878                         dout("? %p idx %lu\n", page, page->index);
 879                         if (locked_pages == 0)
 880                                 lock_page(page);  /* first page */
 881                         else if (!trylock_page(page))
 882                                 break;
 883 
 884                         /* only dirty pages, or our accounting breaks */
 885                         if (unlikely(!PageDirty(page)) ||
 886                             unlikely(page->mapping != mapping)) {
 887                                 dout("!dirty or !mapping %p\n", page);
 888                                 unlock_page(page);
 889                                 continue;
 890                         }
 891                         /* only if matching snap context */
 892                         pgsnapc = page_snap_context(page);
 893                         if (pgsnapc != snapc) {
 894                                 dout("page snapc %p %lld != oldest %p %lld\n",
 895                                      pgsnapc, pgsnapc->seq, snapc, snapc->seq);
 896                                 if (!should_loop &&
 897                                     !ceph_wbc.head_snapc &&
 898                                     wbc->sync_mode != WB_SYNC_NONE)
 899                                         should_loop = true;
 900                                 unlock_page(page);
 901                                 continue;
 902                         }
 903                         if (page_offset(page) >= ceph_wbc.i_size) {
 904                                 dout("%p page eof %llu\n",
 905                                      page, ceph_wbc.i_size);
 906                                 if ((ceph_wbc.size_stable ||
 907                                     page_offset(page) >= i_size_read(inode)) &&
 908                                     clear_page_dirty_for_io(page))
 909                                         mapping->a_ops->invalidatepage(page,
 910                                                                 0, PAGE_SIZE);
 911                                 unlock_page(page);
 912                                 continue;
 913                         }
 914                         if (strip_unit_end && (page->index > strip_unit_end)) {
 915                                 dout("end of strip unit %p\n", page);
 916                                 unlock_page(page);
 917                                 break;
 918                         }
 919                         if (PageWriteback(page)) {
 920                                 if (wbc->sync_mode == WB_SYNC_NONE) {
 921                                         dout("%p under writeback\n", page);
 922                                         unlock_page(page);
 923                                         continue;
 924                                 }
 925                                 dout("waiting on writeback %p\n", page);
 926                                 wait_on_page_writeback(page);
 927                         }
 928 
 929                         if (!clear_page_dirty_for_io(page)) {
 930                                 dout("%p !clear_page_dirty_for_io\n", page);
 931                                 unlock_page(page);
 932                                 continue;
 933                         }
 934 
 935                         /*
 936                          * We have something to write.  If this is
 937                          * the first locked page this time through,
 938                          * calculate max possinle write size and
 939                          * allocate a page array
 940                          */
 941                         if (locked_pages == 0) {
 942                                 u64 objnum;
 943                                 u64 objoff;
 944                                 u32 xlen;
 945 
 946                                 /* prepare async write request */
 947                                 offset = (u64)page_offset(page);
 948                                 ceph_calc_file_object_mapping(&ci->i_layout,
 949                                                               offset, wsize,
 950                                                               &objnum, &objoff,
 951                                                               &xlen);
 952                                 len = xlen;
 953 
 954                                 num_ops = 1;
 955                                 strip_unit_end = page->index +
 956                                         ((len - 1) >> PAGE_SHIFT);
 957 
 958                                 BUG_ON(pages);
 959                                 max_pages = calc_pages_for(0, (u64)len);
 960                                 pages = kmalloc_array(max_pages,
 961                                                       sizeof(*pages),
 962                                                       GFP_NOFS);
 963                                 if (!pages) {
 964                                         pool = fsc->wb_pagevec_pool;
 965                                         pages = mempool_alloc(pool, GFP_NOFS);
 966                                         BUG_ON(!pages);
 967                                 }
 968 
 969                                 len = 0;
 970                         } else if (page->index !=
 971                                    (offset + len) >> PAGE_SHIFT) {
 972                                 if (num_ops >= (pool ?  CEPH_OSD_SLAB_OPS :
 973                                                         CEPH_OSD_MAX_OPS)) {
 974                                         redirty_page_for_writepage(wbc, page);
 975                                         unlock_page(page);
 976                                         break;
 977                                 }
 978 
 979                                 num_ops++;
 980                                 offset = (u64)page_offset(page);
 981                                 len = 0;
 982                         }
 983 
 984                         /* note position of first page in pvec */
 985                         dout("%p will write page %p idx %lu\n",
 986                              inode, page, page->index);
 987 
 988                         if (atomic_long_inc_return(&fsc->writeback_count) >
 989                             CONGESTION_ON_THRESH(
 990                                     fsc->mount_options->congestion_kb)) {
 991                                 set_bdi_congested(inode_to_bdi(inode),
 992                                                   BLK_RW_ASYNC);
 993                         }
 994 
 995 
 996                         pages[locked_pages++] = page;
 997                         pvec.pages[i] = NULL;
 998 
 999                         len += PAGE_SIZE;
1000                 }
1001 
1002                 /* did we get anything? */
1003                 if (!locked_pages)
1004                         goto release_pvec_pages;
1005                 if (i) {
1006                         unsigned j, n = 0;
1007                         /* shift unused page to beginning of pvec */
1008                         for (j = 0; j < pvec_pages; j++) {
1009                                 if (!pvec.pages[j])
1010                                         continue;
1011                                 if (n < j)
1012                                         pvec.pages[n] = pvec.pages[j];
1013                                 n++;
1014                         }
1015                         pvec.nr = n;
1016 
1017                         if (pvec_pages && i == pvec_pages &&
1018                             locked_pages < max_pages) {
1019                                 dout("reached end pvec, trying for more\n");
1020                                 pagevec_release(&pvec);
1021                                 goto get_more_pages;
1022                         }
1023                 }
1024 
1025 new_request:
1026                 offset = page_offset(pages[0]);
1027                 len = wsize;
1028 
1029                 req = ceph_osdc_new_request(&fsc->client->osdc,
1030                                         &ci->i_layout, vino,
1031                                         offset, &len, 0, num_ops,
1032                                         CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE,
1033                                         snapc, ceph_wbc.truncate_seq,
1034                                         ceph_wbc.truncate_size, false);
1035                 if (IS_ERR(req)) {
1036                         req = ceph_osdc_new_request(&fsc->client->osdc,
1037                                                 &ci->i_layout, vino,
1038                                                 offset, &len, 0,
1039                                                 min(num_ops,
1040                                                     CEPH_OSD_SLAB_OPS),
1041                                                 CEPH_OSD_OP_WRITE,
1042                                                 CEPH_OSD_FLAG_WRITE,
1043                                                 snapc, ceph_wbc.truncate_seq,
1044                                                 ceph_wbc.truncate_size, true);
1045                         BUG_ON(IS_ERR(req));
1046                 }
1047                 BUG_ON(len < page_offset(pages[locked_pages - 1]) +
1048                              PAGE_SIZE - offset);
1049 
1050                 req->r_callback = writepages_finish;
1051                 req->r_inode = inode;
1052 
1053                 /* Format the osd request message and submit the write */
1054                 len = 0;
1055                 data_pages = pages;
1056                 op_idx = 0;
1057                 for (i = 0; i < locked_pages; i++) {
1058                         u64 cur_offset = page_offset(pages[i]);
1059                         if (offset + len != cur_offset) {
1060                                 if (op_idx + 1 == req->r_num_ops)
1061                                         break;
1062                                 osd_req_op_extent_dup_last(req, op_idx,
1063                                                            cur_offset - offset);
1064                                 dout("writepages got pages at %llu~%llu\n",
1065                                      offset, len);
1066                                 osd_req_op_extent_osd_data_pages(req, op_idx,
1067                                                         data_pages, len, 0,
1068                                                         !!pool, false);
1069                                 osd_req_op_extent_update(req, op_idx, len);
1070 
1071                                 len = 0;
1072                                 offset = cur_offset; 
1073                                 data_pages = pages + i;
1074                                 op_idx++;
1075                         }
1076 
1077                         set_page_writeback(pages[i]);
1078                         len += PAGE_SIZE;
1079                 }
1080 
1081                 if (ceph_wbc.size_stable) {
1082                         len = min(len, ceph_wbc.i_size - offset);
1083                 } else if (i == locked_pages) {
1084                         /* writepages_finish() clears writeback pages
1085                          * according to the data length, so make sure
1086                          * data length covers all locked pages */
1087                         u64 min_len = len + 1 - PAGE_SIZE;
1088                         len = get_writepages_data_length(inode, pages[i - 1],
1089                                                          offset);
1090                         len = max(len, min_len);
1091                 }
1092                 dout("writepages got pages at %llu~%llu\n", offset, len);
1093 
1094                 osd_req_op_extent_osd_data_pages(req, op_idx, data_pages, len,
1095                                                  0, !!pool, false);
1096                 osd_req_op_extent_update(req, op_idx, len);
1097 
1098                 BUG_ON(op_idx + 1 != req->r_num_ops);
1099 
1100                 pool = NULL;
1101                 if (i < locked_pages) {
1102                         BUG_ON(num_ops <= req->r_num_ops);
1103                         num_ops -= req->r_num_ops;
1104                         locked_pages -= i;
1105 
1106                         /* allocate new pages array for next request */
1107                         data_pages = pages;
1108                         pages = kmalloc_array(locked_pages, sizeof(*pages),
1109                                               GFP_NOFS);
1110                         if (!pages) {
1111                                 pool = fsc->wb_pagevec_pool;
1112                                 pages = mempool_alloc(pool, GFP_NOFS);
1113                                 BUG_ON(!pages);
1114                         }
1115                         memcpy(pages, data_pages + i,
1116                                locked_pages * sizeof(*pages));
1117                         memset(data_pages + i, 0,
1118                                locked_pages * sizeof(*pages));
1119                 } else {
1120                         BUG_ON(num_ops != req->r_num_ops);
1121                         index = pages[i - 1]->index + 1;
1122                         /* request message now owns the pages array */
1123                         pages = NULL;
1124                 }
1125 
1126                 req->r_mtime = inode->i_mtime;
1127                 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
1128                 BUG_ON(rc);
1129                 req = NULL;
1130 
1131                 wbc->nr_to_write -= i;
1132                 if (pages)
1133                         goto new_request;
1134 
1135                 /*
1136                  * We stop writing back only if we are not doing
1137                  * integrity sync. In case of integrity sync we have to
1138                  * keep going until we have written all the pages
1139                  * we tagged for writeback prior to entering this loop.
1140                  */
1141                 if (wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE)
1142                         done = true;
1143 
1144 release_pvec_pages:
1145                 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
1146                      pvec.nr ? pvec.pages[0] : NULL);
1147                 pagevec_release(&pvec);
1148         }
1149 
1150         if (should_loop && !done) {
1151                 /* more to do; loop back to beginning of file */
1152                 dout("writepages looping back to beginning of file\n");
1153                 end = start_index - 1; /* OK even when start_index == 0 */
1154 
1155                 /* to write dirty pages associated with next snapc,
1156                  * we need to wait until current writes complete */
1157                 if (wbc->sync_mode != WB_SYNC_NONE &&
1158                     start_index == 0 && /* all dirty pages were checked */
1159                     !ceph_wbc.head_snapc) {
1160                         struct page *page;
1161                         unsigned i, nr;
1162                         index = 0;
1163                         while ((index <= end) &&
1164                                (nr = pagevec_lookup_tag(&pvec, mapping, &index,
1165                                                 PAGECACHE_TAG_WRITEBACK))) {
1166                                 for (i = 0; i < nr; i++) {
1167                                         page = pvec.pages[i];
1168                                         if (page_snap_context(page) != snapc)
1169                                                 continue;
1170                                         wait_on_page_writeback(page);
1171                                 }
1172                                 pagevec_release(&pvec);
1173                                 cond_resched();
1174                         }
1175                 }
1176 
1177                 start_index = 0;
1178                 index = 0;
1179                 goto retry;
1180         }
1181 
1182         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
1183                 mapping->writeback_index = index;
1184 
1185 out:
1186         ceph_osdc_put_request(req);
1187         ceph_put_snap_context(last_snapc);
1188         dout("writepages dend - startone, rc = %d\n", rc);
1189         return rc;
1190 }
1191 
1192 
1193 
1194 /*
1195  * See if a given @snapc is either writeable, or already written.
1196  */
1197 static int context_is_writeable_or_written(struct inode *inode,
1198                                            struct ceph_snap_context *snapc)
1199 {
1200         struct ceph_snap_context *oldest = get_oldest_context(inode, NULL, NULL);
1201         int ret = !oldest || snapc->seq <= oldest->seq;
1202 
1203         ceph_put_snap_context(oldest);
1204         return ret;
1205 }
1206 
1207 /*
1208  * We are only allowed to write into/dirty the page if the page is
1209  * clean, or already dirty within the same snap context.
1210  *
1211  * called with page locked.
1212  * return success with page locked,
1213  * or any failure (incl -EAGAIN) with page unlocked.
1214  */
1215 static int ceph_update_writeable_page(struct file *file,
1216                             loff_t pos, unsigned len,
1217                             struct page *page)
1218 {
1219         struct inode *inode = file_inode(file);
1220         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1221         struct ceph_inode_info *ci = ceph_inode(inode);
1222         loff_t page_off = pos & PAGE_MASK;
1223         int pos_in_page = pos & ~PAGE_MASK;
1224         int end_in_page = pos_in_page + len;
1225         loff_t i_size;
1226         int r;
1227         struct ceph_snap_context *snapc, *oldest;
1228 
1229         if (READ_ONCE(fsc->mount_state) == CEPH_MOUNT_SHUTDOWN) {
1230                 dout(" page %p forced umount\n", page);
1231                 unlock_page(page);
1232                 return -EIO;
1233         }
1234 
1235 retry_locked:
1236         /* writepages currently holds page lock, but if we change that later, */
1237         wait_on_page_writeback(page);
1238 
1239         snapc = page_snap_context(page);
1240         if (snapc && snapc != ci->i_head_snapc) {
1241                 /*
1242                  * this page is already dirty in another (older) snap
1243                  * context!  is it writeable now?
1244                  */
1245                 oldest = get_oldest_context(inode, NULL, NULL);
1246                 if (snapc->seq > oldest->seq) {
1247                         ceph_put_snap_context(oldest);
1248                         dout(" page %p snapc %p not current or oldest\n",
1249                              page, snapc);
1250                         /*
1251                          * queue for writeback, and wait for snapc to
1252                          * be writeable or written
1253                          */
1254                         snapc = ceph_get_snap_context(snapc);
1255                         unlock_page(page);
1256                         ceph_queue_writeback(inode);
1257                         r = wait_event_killable(ci->i_cap_wq,
1258                                context_is_writeable_or_written(inode, snapc));
1259                         ceph_put_snap_context(snapc);
1260                         if (r == -ERESTARTSYS)
1261                                 return r;
1262                         return -EAGAIN;
1263                 }
1264                 ceph_put_snap_context(oldest);
1265 
1266                 /* yay, writeable, do it now (without dropping page lock) */
1267                 dout(" page %p snapc %p not current, but oldest\n",
1268                      page, snapc);
1269                 if (!clear_page_dirty_for_io(page))
1270                         goto retry_locked;
1271                 r = writepage_nounlock(page, NULL);
1272                 if (r < 0)
1273                         goto fail_unlock;
1274                 goto retry_locked;
1275         }
1276 
1277         if (PageUptodate(page)) {
1278                 dout(" page %p already uptodate\n", page);
1279                 return 0;
1280         }
1281 
1282         /* full page? */
1283         if (pos_in_page == 0 && len == PAGE_SIZE)
1284                 return 0;
1285 
1286         /* past end of file? */
1287         i_size = i_size_read(inode);
1288 
1289         if (page_off >= i_size ||
1290             (pos_in_page == 0 && (pos+len) >= i_size &&
1291              end_in_page - pos_in_page != PAGE_SIZE)) {
1292                 dout(" zeroing %p 0 - %d and %d - %d\n",
1293                      page, pos_in_page, end_in_page, (int)PAGE_SIZE);
1294                 zero_user_segments(page,
1295                                    0, pos_in_page,
1296                                    end_in_page, PAGE_SIZE);
1297                 return 0;
1298         }
1299 
1300         /* we need to read it. */
1301         r = ceph_do_readpage(file, page);
1302         if (r < 0) {
1303                 if (r == -EINPROGRESS)
1304                         return -EAGAIN;
1305                 goto fail_unlock;
1306         }
1307         goto retry_locked;
1308 fail_unlock:
1309         unlock_page(page);
1310         return r;
1311 }
1312 
1313 /*
1314  * We are only allowed to write into/dirty the page if the page is
1315  * clean, or already dirty within the same snap context.
1316  */
1317 static int ceph_write_begin(struct file *file, struct address_space *mapping,
1318                             loff_t pos, unsigned len, unsigned flags,
1319                             struct page **pagep, void **fsdata)
1320 {
1321         struct inode *inode = file_inode(file);
1322         struct page *page;
1323         pgoff_t index = pos >> PAGE_SHIFT;
1324         int r;
1325 
1326         do {
1327                 /* get a page */
1328                 page = grab_cache_page_write_begin(mapping, index, 0);
1329                 if (!page)
1330                         return -ENOMEM;
1331 
1332                 dout("write_begin file %p inode %p page %p %d~%d\n", file,
1333                      inode, page, (int)pos, (int)len);
1334 
1335                 r = ceph_update_writeable_page(file, pos, len, page);
1336                 if (r < 0)
1337                         put_page(page);
1338                 else
1339                         *pagep = page;
1340         } while (r == -EAGAIN);
1341 
1342         return r;
1343 }
1344 
1345 /*
1346  * we don't do anything in here that simple_write_end doesn't do
1347  * except adjust dirty page accounting
1348  */
1349 static int ceph_write_end(struct file *file, struct address_space *mapping,
1350                           loff_t pos, unsigned len, unsigned copied,
1351                           struct page *page, void *fsdata)
1352 {
1353         struct inode *inode = file_inode(file);
1354         bool check_cap = false;
1355 
1356         dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1357              inode, page, (int)pos, (int)copied, (int)len);
1358 
1359         /* zero the stale part of the page if we did a short copy */
1360         if (!PageUptodate(page)) {
1361                 if (copied < len) {
1362                         copied = 0;
1363                         goto out;
1364                 }
1365                 SetPageUptodate(page);
1366         }
1367 
1368         /* did file size increase? */
1369         if (pos+copied > i_size_read(inode))
1370                 check_cap = ceph_inode_set_size(inode, pos+copied);
1371 
1372         set_page_dirty(page);
1373 
1374 out:
1375         unlock_page(page);
1376         put_page(page);
1377 
1378         if (check_cap)
1379                 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1380 
1381         return copied;
1382 }
1383 
1384 /*
1385  * we set .direct_IO to indicate direct io is supported, but since we
1386  * intercept O_DIRECT reads and writes early, this function should
1387  * never get called.
1388  */
1389 static ssize_t ceph_direct_io(struct kiocb *iocb, struct iov_iter *iter)
1390 {
1391         WARN_ON(1);
1392         return -EINVAL;
1393 }
1394 
1395 const struct address_space_operations ceph_aops = {
1396         .readpage = ceph_readpage,
1397         .readpages = ceph_readpages,
1398         .writepage = ceph_writepage,
1399         .writepages = ceph_writepages_start,
1400         .write_begin = ceph_write_begin,
1401         .write_end = ceph_write_end,
1402         .set_page_dirty = ceph_set_page_dirty,
1403         .invalidatepage = ceph_invalidatepage,
1404         .releasepage = ceph_releasepage,
1405         .direct_IO = ceph_direct_io,
1406 };
1407 
1408 static void ceph_block_sigs(sigset_t *oldset)
1409 {
1410         sigset_t mask;
1411         siginitsetinv(&mask, sigmask(SIGKILL));
1412         sigprocmask(SIG_BLOCK, &mask, oldset);
1413 }
1414 
1415 static void ceph_restore_sigs(sigset_t *oldset)
1416 {
1417         sigprocmask(SIG_SETMASK, oldset, NULL);
1418 }
1419 
1420 /*
1421  * vm ops
1422  */
1423 static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf)
1424 {
1425         struct vm_area_struct *vma = vmf->vma;
1426         struct inode *inode = file_inode(vma->vm_file);
1427         struct ceph_inode_info *ci = ceph_inode(inode);
1428         struct ceph_file_info *fi = vma->vm_file->private_data;
1429         struct page *pinned_page = NULL;
1430         loff_t off = vmf->pgoff << PAGE_SHIFT;
1431         int want, got, err;
1432         sigset_t oldset;
1433         vm_fault_t ret = VM_FAULT_SIGBUS;
1434 
1435         ceph_block_sigs(&oldset);
1436 
1437         dout("filemap_fault %p %llx.%llx %llu~%zd trying to get caps\n",
1438              inode, ceph_vinop(inode), off, (size_t)PAGE_SIZE);
1439         if (fi->fmode & CEPH_FILE_MODE_LAZY)
1440                 want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
1441         else
1442                 want = CEPH_CAP_FILE_CACHE;
1443 
1444         got = 0;
1445         err = ceph_get_caps(vma->vm_file, CEPH_CAP_FILE_RD, want, -1,
1446                             &got, &pinned_page);
1447         if (err < 0)
1448                 goto out_restore;
1449 
1450         dout("filemap_fault %p %llu~%zd got cap refs on %s\n",
1451              inode, off, (size_t)PAGE_SIZE, ceph_cap_string(got));
1452 
1453         if ((got & (CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO)) ||
1454             ci->i_inline_version == CEPH_INLINE_NONE) {
1455                 CEPH_DEFINE_RW_CONTEXT(rw_ctx, got);
1456                 ceph_add_rw_context(fi, &rw_ctx);
1457                 ret = filemap_fault(vmf);
1458                 ceph_del_rw_context(fi, &rw_ctx);
1459                 dout("filemap_fault %p %llu~%zd drop cap refs %s ret %x\n",
1460                         inode, off, (size_t)PAGE_SIZE,
1461                                 ceph_cap_string(got), ret);
1462         } else
1463                 err = -EAGAIN;
1464 
1465         if (pinned_page)
1466                 put_page(pinned_page);
1467         ceph_put_cap_refs(ci, got);
1468 
1469         if (err != -EAGAIN)
1470                 goto out_restore;
1471 
1472         /* read inline data */
1473         if (off >= PAGE_SIZE) {
1474                 /* does not support inline data > PAGE_SIZE */
1475                 ret = VM_FAULT_SIGBUS;
1476         } else {
1477                 struct address_space *mapping = inode->i_mapping;
1478                 struct page *page = find_or_create_page(mapping, 0,
1479                                                 mapping_gfp_constraint(mapping,
1480                                                 ~__GFP_FS));
1481                 if (!page) {
1482                         ret = VM_FAULT_OOM;
1483                         goto out_inline;
1484                 }
1485                 err = __ceph_do_getattr(inode, page,
1486                                          CEPH_STAT_CAP_INLINE_DATA, true);
1487                 if (err < 0 || off >= i_size_read(inode)) {
1488                         unlock_page(page);
1489                         put_page(page);
1490                         ret = vmf_error(err);
1491                         goto out_inline;
1492                 }
1493                 if (err < PAGE_SIZE)
1494                         zero_user_segment(page, err, PAGE_SIZE);
1495                 else
1496                         flush_dcache_page(page);
1497                 SetPageUptodate(page);
1498                 vmf->page = page;
1499                 ret = VM_FAULT_MAJOR | VM_FAULT_LOCKED;
1500 out_inline:
1501                 dout("filemap_fault %p %llu~%zd read inline data ret %x\n",
1502                      inode, off, (size_t)PAGE_SIZE, ret);
1503         }
1504 out_restore:
1505         ceph_restore_sigs(&oldset);
1506         if (err < 0)
1507                 ret = vmf_error(err);
1508 
1509         return ret;
1510 }
1511 
1512 /*
1513  * Reuse write_begin here for simplicity.
1514  */
1515 static vm_fault_t ceph_page_mkwrite(struct vm_fault *vmf)
1516 {
1517         struct vm_area_struct *vma = vmf->vma;
1518         struct inode *inode = file_inode(vma->vm_file);
1519         struct ceph_inode_info *ci = ceph_inode(inode);
1520         struct ceph_file_info *fi = vma->vm_file->private_data;
1521         struct ceph_cap_flush *prealloc_cf;
1522         struct page *page = vmf->page;
1523         loff_t off = page_offset(page);
1524         loff_t size = i_size_read(inode);
1525         size_t len;
1526         int want, got, err;
1527         sigset_t oldset;
1528         vm_fault_t ret = VM_FAULT_SIGBUS;
1529 
1530         prealloc_cf = ceph_alloc_cap_flush();
1531         if (!prealloc_cf)
1532                 return VM_FAULT_OOM;
1533 
1534         sb_start_pagefault(inode->i_sb);
1535         ceph_block_sigs(&oldset);
1536 
1537         if (ci->i_inline_version != CEPH_INLINE_NONE) {
1538                 struct page *locked_page = NULL;
1539                 if (off == 0) {
1540                         lock_page(page);
1541                         locked_page = page;
1542                 }
1543                 err = ceph_uninline_data(vma->vm_file, locked_page);
1544                 if (locked_page)
1545                         unlock_page(locked_page);
1546                 if (err < 0)
1547                         goto out_free;
1548         }
1549 
1550         if (off + PAGE_SIZE <= size)
1551                 len = PAGE_SIZE;
1552         else
1553                 len = size & ~PAGE_MASK;
1554 
1555         dout("page_mkwrite %p %llx.%llx %llu~%zd getting caps i_size %llu\n",
1556              inode, ceph_vinop(inode), off, len, size);
1557         if (fi->fmode & CEPH_FILE_MODE_LAZY)
1558                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
1559         else
1560                 want = CEPH_CAP_FILE_BUFFER;
1561 
1562         got = 0;
1563         err = ceph_get_caps(vma->vm_file, CEPH_CAP_FILE_WR, want, off + len,
1564                             &got, NULL);
1565         if (err < 0)
1566                 goto out_free;
1567 
1568         dout("page_mkwrite %p %llu~%zd got cap refs on %s\n",
1569              inode, off, len, ceph_cap_string(got));
1570 
1571         /* Update time before taking page lock */
1572         file_update_time(vma->vm_file);
1573         inode_inc_iversion_raw(inode);
1574 
1575         do {
1576                 lock_page(page);
1577 
1578                 if ((off > size) || (page->mapping != inode->i_mapping)) {
1579                         unlock_page(page);
1580                         ret = VM_FAULT_NOPAGE;
1581                         break;
1582                 }
1583 
1584                 err = ceph_update_writeable_page(vma->vm_file, off, len, page);
1585                 if (err >= 0) {
1586                         /* success.  we'll keep the page locked. */
1587                         set_page_dirty(page);
1588                         ret = VM_FAULT_LOCKED;
1589                 }
1590         } while (err == -EAGAIN);
1591 
1592         if (ret == VM_FAULT_LOCKED ||
1593             ci->i_inline_version != CEPH_INLINE_NONE) {
1594                 int dirty;
1595                 spin_lock(&ci->i_ceph_lock);
1596                 ci->i_inline_version = CEPH_INLINE_NONE;
1597                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR,
1598                                                &prealloc_cf);
1599                 spin_unlock(&ci->i_ceph_lock);
1600                 if (dirty)
1601                         __mark_inode_dirty(inode, dirty);
1602         }
1603 
1604         dout("page_mkwrite %p %llu~%zd dropping cap refs on %s ret %x\n",
1605              inode, off, len, ceph_cap_string(got), ret);
1606         ceph_put_cap_refs(ci, got);
1607 out_free:
1608         ceph_restore_sigs(&oldset);
1609         sb_end_pagefault(inode->i_sb);
1610         ceph_free_cap_flush(prealloc_cf);
1611         if (err < 0)
1612                 ret = vmf_error(err);
1613         return ret;
1614 }
1615 
1616 void ceph_fill_inline_data(struct inode *inode, struct page *locked_page,
1617                            char *data, size_t len)
1618 {
1619         struct address_space *mapping = inode->i_mapping;
1620         struct page *page;
1621 
1622         if (locked_page) {
1623                 page = locked_page;
1624         } else {
1625                 if (i_size_read(inode) == 0)
1626                         return;
1627                 page = find_or_create_page(mapping, 0,
1628                                            mapping_gfp_constraint(mapping,
1629                                            ~__GFP_FS));
1630                 if (!page)
1631                         return;
1632                 if (PageUptodate(page)) {
1633                         unlock_page(page);
1634                         put_page(page);
1635                         return;
1636                 }
1637         }
1638 
1639         dout("fill_inline_data %p %llx.%llx len %zu locked_page %p\n",
1640              inode, ceph_vinop(inode), len, locked_page);
1641 
1642         if (len > 0) {
1643                 void *kaddr = kmap_atomic(page);
1644                 memcpy(kaddr, data, len);
1645                 kunmap_atomic(kaddr);
1646         }
1647 
1648         if (page != locked_page) {
1649                 if (len < PAGE_SIZE)
1650                         zero_user_segment(page, len, PAGE_SIZE);
1651                 else
1652                         flush_dcache_page(page);
1653 
1654                 SetPageUptodate(page);
1655                 unlock_page(page);
1656                 put_page(page);
1657         }
1658 }
1659 
1660 int ceph_uninline_data(struct file *filp, struct page *locked_page)
1661 {
1662         struct inode *inode = file_inode(filp);
1663         struct ceph_inode_info *ci = ceph_inode(inode);
1664         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1665         struct ceph_osd_request *req;
1666         struct page *page = NULL;
1667         u64 len, inline_version;
1668         int err = 0;
1669         bool from_pagecache = false;
1670 
1671         spin_lock(&ci->i_ceph_lock);
1672         inline_version = ci->i_inline_version;
1673         spin_unlock(&ci->i_ceph_lock);
1674 
1675         dout("uninline_data %p %llx.%llx inline_version %llu\n",
1676              inode, ceph_vinop(inode), inline_version);
1677 
1678         if (inline_version == 1 || /* initial version, no data */
1679             inline_version == CEPH_INLINE_NONE)
1680                 goto out;
1681 
1682         if (locked_page) {
1683                 page = locked_page;
1684                 WARN_ON(!PageUptodate(page));
1685         } else if (ceph_caps_issued(ci) &
1686                    (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) {
1687                 page = find_get_page(inode->i_mapping, 0);
1688                 if (page) {
1689                         if (PageUptodate(page)) {
1690                                 from_pagecache = true;
1691                                 lock_page(page);
1692                         } else {
1693                                 put_page(page);
1694                                 page = NULL;
1695                         }
1696                 }
1697         }
1698 
1699         if (page) {
1700                 len = i_size_read(inode);
1701                 if (len > PAGE_SIZE)
1702                         len = PAGE_SIZE;
1703         } else {
1704                 page = __page_cache_alloc(GFP_NOFS);
1705                 if (!page) {
1706                         err = -ENOMEM;
1707                         goto out;
1708                 }
1709                 err = __ceph_do_getattr(inode, page,
1710                                         CEPH_STAT_CAP_INLINE_DATA, true);
1711                 if (err < 0) {
1712                         /* no inline data */
1713                         if (err == -ENODATA)
1714                                 err = 0;
1715                         goto out;
1716                 }
1717                 len = err;
1718         }
1719 
1720         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
1721                                     ceph_vino(inode), 0, &len, 0, 1,
1722                                     CEPH_OSD_OP_CREATE, CEPH_OSD_FLAG_WRITE,
1723                                     NULL, 0, 0, false);
1724         if (IS_ERR(req)) {
1725                 err = PTR_ERR(req);
1726                 goto out;
1727         }
1728 
1729         req->r_mtime = inode->i_mtime;
1730         err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
1731         if (!err)
1732                 err = ceph_osdc_wait_request(&fsc->client->osdc, req);
1733         ceph_osdc_put_request(req);
1734         if (err < 0)
1735                 goto out;
1736 
1737         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
1738                                     ceph_vino(inode), 0, &len, 1, 3,
1739                                     CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE,
1740                                     NULL, ci->i_truncate_seq,
1741                                     ci->i_truncate_size, false);
1742         if (IS_ERR(req)) {
1743                 err = PTR_ERR(req);
1744                 goto out;
1745         }
1746 
1747         osd_req_op_extent_osd_data_pages(req, 1, &page, len, 0, false, false);
1748 
1749         {
1750                 __le64 xattr_buf = cpu_to_le64(inline_version);
1751                 err = osd_req_op_xattr_init(req, 0, CEPH_OSD_OP_CMPXATTR,
1752                                             "inline_version", &xattr_buf,
1753                                             sizeof(xattr_buf),
1754                                             CEPH_OSD_CMPXATTR_OP_GT,
1755                                             CEPH_OSD_CMPXATTR_MODE_U64);
1756                 if (err)
1757                         goto out_put;
1758         }
1759 
1760         {
1761                 char xattr_buf[32];
1762                 int xattr_len = snprintf(xattr_buf, sizeof(xattr_buf),
1763                                          "%llu", inline_version);
1764                 err = osd_req_op_xattr_init(req, 2, CEPH_OSD_OP_SETXATTR,
1765                                             "inline_version",
1766                                             xattr_buf, xattr_len, 0, 0);
1767                 if (err)
1768                         goto out_put;
1769         }
1770 
1771         req->r_mtime = inode->i_mtime;
1772         err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
1773         if (!err)
1774                 err = ceph_osdc_wait_request(&fsc->client->osdc, req);
1775 out_put:
1776         ceph_osdc_put_request(req);
1777         if (err == -ECANCELED)
1778                 err = 0;
1779 out:
1780         if (page && page != locked_page) {
1781                 if (from_pagecache) {
1782                         unlock_page(page);
1783                         put_page(page);
1784                 } else
1785                         __free_pages(page, 0);
1786         }
1787 
1788         dout("uninline_data %p %llx.%llx inline_version %llu = %d\n",
1789              inode, ceph_vinop(inode), inline_version, err);
1790         return err;
1791 }
1792 
1793 static const struct vm_operations_struct ceph_vmops = {
1794         .fault          = ceph_filemap_fault,
1795         .page_mkwrite   = ceph_page_mkwrite,
1796 };
1797 
1798 int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1799 {
1800         struct address_space *mapping = file->f_mapping;
1801 
1802         if (!mapping->a_ops->readpage)
1803                 return -ENOEXEC;
1804         file_accessed(file);
1805         vma->vm_ops = &ceph_vmops;
1806         return 0;
1807 }
1808 
1809 enum {
1810         POOL_READ       = 1,
1811         POOL_WRITE      = 2,
1812 };
1813 
1814 static int __ceph_pool_perm_get(struct ceph_inode_info *ci,
1815                                 s64 pool, struct ceph_string *pool_ns)
1816 {
1817         struct ceph_fs_client *fsc = ceph_inode_to_client(&ci->vfs_inode);
1818         struct ceph_mds_client *mdsc = fsc->mdsc;
1819         struct ceph_osd_request *rd_req = NULL, *wr_req = NULL;
1820         struct rb_node **p, *parent;
1821         struct ceph_pool_perm *perm;
1822         struct page **pages;
1823         size_t pool_ns_len;
1824         int err = 0, err2 = 0, have = 0;
1825 
1826         down_read(&mdsc->pool_perm_rwsem);
1827         p = &mdsc->pool_perm_tree.rb_node;
1828         while (*p) {
1829                 perm = rb_entry(*p, struct ceph_pool_perm, node);
1830                 if (pool < perm->pool)
1831                         p = &(*p)->rb_left;
1832                 else if (pool > perm->pool)
1833                         p = &(*p)->rb_right;
1834                 else {
1835                         int ret = ceph_compare_string(pool_ns,
1836                                                 perm->pool_ns,
1837                                                 perm->pool_ns_len);
1838                         if (ret < 0)
1839                                 p = &(*p)->rb_left;
1840                         else if (ret > 0)
1841                                 p = &(*p)->rb_right;
1842                         else {
1843                                 have = perm->perm;
1844                                 break;
1845                         }
1846                 }
1847         }
1848         up_read(&mdsc->pool_perm_rwsem);
1849         if (*p)
1850                 goto out;
1851 
1852         if (pool_ns)
1853                 dout("__ceph_pool_perm_get pool %lld ns %.*s no perm cached\n",
1854                      pool, (int)pool_ns->len, pool_ns->str);
1855         else
1856                 dout("__ceph_pool_perm_get pool %lld no perm cached\n", pool);
1857 
1858         down_write(&mdsc->pool_perm_rwsem);
1859         p = &mdsc->pool_perm_tree.rb_node;
1860         parent = NULL;
1861         while (*p) {
1862                 parent = *p;
1863                 perm = rb_entry(parent, struct ceph_pool_perm, node);
1864                 if (pool < perm->pool)
1865                         p = &(*p)->rb_left;
1866                 else if (pool > perm->pool)
1867                         p = &(*p)->rb_right;
1868                 else {
1869                         int ret = ceph_compare_string(pool_ns,
1870                                                 perm->pool_ns,
1871                                                 perm->pool_ns_len);
1872                         if (ret < 0)
1873                                 p = &(*p)->rb_left;
1874                         else if (ret > 0)
1875                                 p = &(*p)->rb_right;
1876                         else {
1877                                 have = perm->perm;
1878                                 break;
1879                         }
1880                 }
1881         }
1882         if (*p) {
1883                 up_write(&mdsc->pool_perm_rwsem);
1884                 goto out;
1885         }
1886 
1887         rd_req = ceph_osdc_alloc_request(&fsc->client->osdc, NULL,
1888                                          1, false, GFP_NOFS);
1889         if (!rd_req) {
1890                 err = -ENOMEM;
1891                 goto out_unlock;
1892         }
1893 
1894         rd_req->r_flags = CEPH_OSD_FLAG_READ;
1895         osd_req_op_init(rd_req, 0, CEPH_OSD_OP_STAT, 0);
1896         rd_req->r_base_oloc.pool = pool;
1897         if (pool_ns)
1898                 rd_req->r_base_oloc.pool_ns = ceph_get_string(pool_ns);
1899         ceph_oid_printf(&rd_req->r_base_oid, "%llx.00000000", ci->i_vino.ino);
1900 
1901         err = ceph_osdc_alloc_messages(rd_req, GFP_NOFS);
1902         if (err)
1903                 goto out_unlock;
1904 
1905         wr_req = ceph_osdc_alloc_request(&fsc->client->osdc, NULL,
1906                                          1, false, GFP_NOFS);
1907         if (!wr_req) {
1908                 err = -ENOMEM;
1909                 goto out_unlock;
1910         }
1911 
1912         wr_req->r_flags = CEPH_OSD_FLAG_WRITE;
1913         osd_req_op_init(wr_req, 0, CEPH_OSD_OP_CREATE, CEPH_OSD_OP_FLAG_EXCL);
1914         ceph_oloc_copy(&wr_req->r_base_oloc, &rd_req->r_base_oloc);
1915         ceph_oid_copy(&wr_req->r_base_oid, &rd_req->r_base_oid);
1916 
1917         err = ceph_osdc_alloc_messages(wr_req, GFP_NOFS);
1918         if (err)
1919                 goto out_unlock;
1920 
1921         /* one page should be large enough for STAT data */
1922         pages = ceph_alloc_page_vector(1, GFP_KERNEL);
1923         if (IS_ERR(pages)) {
1924                 err = PTR_ERR(pages);
1925                 goto out_unlock;
1926         }
1927 
1928         osd_req_op_raw_data_in_pages(rd_req, 0, pages, PAGE_SIZE,
1929                                      0, false, true);
1930         err = ceph_osdc_start_request(&fsc->client->osdc, rd_req, false);
1931 
1932         wr_req->r_mtime = ci->vfs_inode.i_mtime;
1933         err2 = ceph_osdc_start_request(&fsc->client->osdc, wr_req, false);
1934 
1935         if (!err)
1936                 err = ceph_osdc_wait_request(&fsc->client->osdc, rd_req);
1937         if (!err2)
1938                 err2 = ceph_osdc_wait_request(&fsc->client->osdc, wr_req);
1939 
1940         if (err >= 0 || err == -ENOENT)
1941                 have |= POOL_READ;
1942         else if (err != -EPERM) {
1943                 if (err == -EBLACKLISTED)
1944                         fsc->blacklisted = true;
1945                 goto out_unlock;
1946         }
1947 
1948         if (err2 == 0 || err2 == -EEXIST)
1949                 have |= POOL_WRITE;
1950         else if (err2 != -EPERM) {
1951                 if (err2 == -EBLACKLISTED)
1952                         fsc->blacklisted = true;
1953                 err = err2;
1954                 goto out_unlock;
1955         }
1956 
1957         pool_ns_len = pool_ns ? pool_ns->len : 0;
1958         perm = kmalloc(sizeof(*perm) + pool_ns_len + 1, GFP_NOFS);
1959         if (!perm) {
1960                 err = -ENOMEM;
1961                 goto out_unlock;
1962         }
1963 
1964         perm->pool = pool;
1965         perm->perm = have;
1966         perm->pool_ns_len = pool_ns_len;
1967         if (pool_ns_len > 0)
1968                 memcpy(perm->pool_ns, pool_ns->str, pool_ns_len);
1969         perm->pool_ns[pool_ns_len] = 0;
1970 
1971         rb_link_node(&perm->node, parent, p);
1972         rb_insert_color(&perm->node, &mdsc->pool_perm_tree);
1973         err = 0;
1974 out_unlock:
1975         up_write(&mdsc->pool_perm_rwsem);
1976 
1977         ceph_osdc_put_request(rd_req);
1978         ceph_osdc_put_request(wr_req);
1979 out:
1980         if (!err)
1981                 err = have;
1982         if (pool_ns)
1983                 dout("__ceph_pool_perm_get pool %lld ns %.*s result = %d\n",
1984                      pool, (int)pool_ns->len, pool_ns->str, err);
1985         else
1986                 dout("__ceph_pool_perm_get pool %lld result = %d\n", pool, err);
1987         return err;
1988 }
1989 
1990 int ceph_pool_perm_check(struct inode *inode, int need)
1991 {
1992         struct ceph_inode_info *ci = ceph_inode(inode);
1993         struct ceph_string *pool_ns;
1994         s64 pool;
1995         int ret, flags;
1996 
1997         if (ci->i_vino.snap != CEPH_NOSNAP) {
1998                 /*
1999                  * Pool permission check needs to write to the first object.
2000                  * But for snapshot, head of the first object may have alread
2001                  * been deleted. Skip check to avoid creating orphan object.
2002                  */
2003                 return 0;
2004         }
2005 
2006         if (ceph_test_mount_opt(ceph_inode_to_client(inode),
2007                                 NOPOOLPERM))
2008                 return 0;
2009 
2010         spin_lock(&ci->i_ceph_lock);
2011         flags = ci->i_ceph_flags;
2012         pool = ci->i_layout.pool_id;
2013         spin_unlock(&ci->i_ceph_lock);
2014 check:
2015         if (flags & CEPH_I_POOL_PERM) {
2016                 if ((need & CEPH_CAP_FILE_RD) && !(flags & CEPH_I_POOL_RD)) {
2017                         dout("ceph_pool_perm_check pool %lld no read perm\n",
2018                              pool);
2019                         return -EPERM;
2020                 }
2021                 if ((need & CEPH_CAP_FILE_WR) && !(flags & CEPH_I_POOL_WR)) {
2022                         dout("ceph_pool_perm_check pool %lld no write perm\n",
2023                              pool);
2024                         return -EPERM;
2025                 }
2026                 return 0;
2027         }
2028 
2029         pool_ns = ceph_try_get_string(ci->i_layout.pool_ns);
2030         ret = __ceph_pool_perm_get(ci, pool, pool_ns);
2031         ceph_put_string(pool_ns);
2032         if (ret < 0)
2033                 return ret;
2034 
2035         flags = CEPH_I_POOL_PERM;
2036         if (ret & POOL_READ)
2037                 flags |= CEPH_I_POOL_RD;
2038         if (ret & POOL_WRITE)
2039                 flags |= CEPH_I_POOL_WR;
2040 
2041         spin_lock(&ci->i_ceph_lock);
2042         if (pool == ci->i_layout.pool_id &&
2043             pool_ns == rcu_dereference_raw(ci->i_layout.pool_ns)) {
2044                 ci->i_ceph_flags |= flags;
2045         } else {
2046                 pool = ci->i_layout.pool_id;
2047                 flags = ci->i_ceph_flags;
2048         }
2049         spin_unlock(&ci->i_ceph_lock);
2050         goto check;
2051 }
2052 
2053 void ceph_pool_perm_destroy(struct ceph_mds_client *mdsc)
2054 {
2055         struct ceph_pool_perm *perm;
2056         struct rb_node *n;
2057 
2058         while (!RB_EMPTY_ROOT(&mdsc->pool_perm_tree)) {
2059                 n = rb_first(&mdsc->pool_perm_tree);
2060                 perm = rb_entry(n, struct ceph_pool_perm, node);
2061                 rb_erase(n, &mdsc->pool_perm_tree);
2062                 kfree(perm);
2063         }
2064 }