linux/fs/ceph/file.c
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   1#include <linux/ceph/ceph_debug.h>
   2
   3#include <linux/module.h>
   4#include <linux/sched.h>
   5#include <linux/slab.h>
   6#include <linux/file.h>
   7#include <linux/mount.h>
   8#include <linux/namei.h>
   9#include <linux/writeback.h>
  10#include <linux/aio.h>
  11
  12#include "super.h"
  13#include "mds_client.h"
  14
  15/*
  16 * Ceph file operations
  17 *
  18 * Implement basic open/close functionality, and implement
  19 * read/write.
  20 *
  21 * We implement three modes of file I/O:
  22 *  - buffered uses the generic_file_aio_{read,write} helpers
  23 *
  24 *  - synchronous is used when there is multi-client read/write
  25 *    sharing, avoids the page cache, and synchronously waits for an
  26 *    ack from the OSD.
  27 *
  28 *  - direct io takes the variant of the sync path that references
  29 *    user pages directly.
  30 *
  31 * fsync() flushes and waits on dirty pages, but just queues metadata
  32 * for writeback: since the MDS can recover size and mtime there is no
  33 * need to wait for MDS acknowledgement.
  34 */
  35
  36
  37/*
  38 * Prepare an open request.  Preallocate ceph_cap to avoid an
  39 * inopportune ENOMEM later.
  40 */
  41static struct ceph_mds_request *
  42prepare_open_request(struct super_block *sb, int flags, int create_mode)
  43{
  44        struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
  45        struct ceph_mds_client *mdsc = fsc->mdsc;
  46        struct ceph_mds_request *req;
  47        int want_auth = USE_ANY_MDS;
  48        int op = (flags & O_CREAT) ? CEPH_MDS_OP_CREATE : CEPH_MDS_OP_OPEN;
  49
  50        if (flags & (O_WRONLY|O_RDWR|O_CREAT|O_TRUNC))
  51                want_auth = USE_AUTH_MDS;
  52
  53        req = ceph_mdsc_create_request(mdsc, op, want_auth);
  54        if (IS_ERR(req))
  55                goto out;
  56        req->r_fmode = ceph_flags_to_mode(flags);
  57        req->r_args.open.flags = cpu_to_le32(flags);
  58        req->r_args.open.mode = cpu_to_le32(create_mode);
  59out:
  60        return req;
  61}
  62
  63/*
  64 * initialize private struct file data.
  65 * if we fail, clean up by dropping fmode reference on the ceph_inode
  66 */
  67static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
  68{
  69        struct ceph_file_info *cf;
  70        int ret = 0;
  71
  72        switch (inode->i_mode & S_IFMT) {
  73        case S_IFREG:
  74        case S_IFDIR:
  75                dout("init_file %p %p 0%o (regular)\n", inode, file,
  76                     inode->i_mode);
  77                cf = kmem_cache_alloc(ceph_file_cachep, GFP_NOFS | __GFP_ZERO);
  78                if (cf == NULL) {
  79                        ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
  80                        return -ENOMEM;
  81                }
  82                cf->fmode = fmode;
  83                cf->next_offset = 2;
  84                file->private_data = cf;
  85                BUG_ON(inode->i_fop->release != ceph_release);
  86                break;
  87
  88        case S_IFLNK:
  89                dout("init_file %p %p 0%o (symlink)\n", inode, file,
  90                     inode->i_mode);
  91                ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
  92                break;
  93
  94        default:
  95                dout("init_file %p %p 0%o (special)\n", inode, file,
  96                     inode->i_mode);
  97                /*
  98                 * we need to drop the open ref now, since we don't
  99                 * have .release set to ceph_release.
 100                 */
 101                ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
 102                BUG_ON(inode->i_fop->release == ceph_release);
 103
 104                /* call the proper open fop */
 105                ret = inode->i_fop->open(inode, file);
 106        }
 107        return ret;
 108}
 109
 110/*
 111 * If we already have the requisite capabilities, we can satisfy
 112 * the open request locally (no need to request new caps from the
 113 * MDS).  We do, however, need to inform the MDS (asynchronously)
 114 * if our wanted caps set expands.
 115 */
 116int ceph_open(struct inode *inode, struct file *file)
 117{
 118        struct ceph_inode_info *ci = ceph_inode(inode);
 119        struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
 120        struct ceph_mds_client *mdsc = fsc->mdsc;
 121        struct ceph_mds_request *req;
 122        struct ceph_file_info *cf = file->private_data;
 123        struct inode *parent_inode = NULL;
 124        int err;
 125        int flags, fmode, wanted;
 126
 127        if (cf) {
 128                dout("open file %p is already opened\n", file);
 129                return 0;
 130        }
 131
 132        /* filter out O_CREAT|O_EXCL; vfs did that already.  yuck. */
 133        flags = file->f_flags & ~(O_CREAT|O_EXCL);
 134        if (S_ISDIR(inode->i_mode))
 135                flags = O_DIRECTORY;  /* mds likes to know */
 136
 137        dout("open inode %p ino %llx.%llx file %p flags %d (%d)\n", inode,
 138             ceph_vinop(inode), file, flags, file->f_flags);
 139        fmode = ceph_flags_to_mode(flags);
 140        wanted = ceph_caps_for_mode(fmode);
 141
 142        /* snapped files are read-only */
 143        if (ceph_snap(inode) != CEPH_NOSNAP && (file->f_mode & FMODE_WRITE))
 144                return -EROFS;
 145
 146        /* trivially open snapdir */
 147        if (ceph_snap(inode) == CEPH_SNAPDIR) {
 148                spin_lock(&ci->i_ceph_lock);
 149                __ceph_get_fmode(ci, fmode);
 150                spin_unlock(&ci->i_ceph_lock);
 151                return ceph_init_file(inode, file, fmode);
 152        }
 153
 154        /*
 155         * No need to block if we have caps on the auth MDS (for
 156         * write) or any MDS (for read).  Update wanted set
 157         * asynchronously.
 158         */
 159        spin_lock(&ci->i_ceph_lock);
 160        if (__ceph_is_any_real_caps(ci) &&
 161            (((fmode & CEPH_FILE_MODE_WR) == 0) || ci->i_auth_cap)) {
 162                int mds_wanted = __ceph_caps_mds_wanted(ci);
 163                int issued = __ceph_caps_issued(ci, NULL);
 164
 165                dout("open %p fmode %d want %s issued %s using existing\n",
 166                     inode, fmode, ceph_cap_string(wanted),
 167                     ceph_cap_string(issued));
 168                __ceph_get_fmode(ci, fmode);
 169                spin_unlock(&ci->i_ceph_lock);
 170
 171                /* adjust wanted? */
 172                if ((issued & wanted) != wanted &&
 173                    (mds_wanted & wanted) != wanted &&
 174                    ceph_snap(inode) != CEPH_SNAPDIR)
 175                        ceph_check_caps(ci, 0, NULL);
 176
 177                return ceph_init_file(inode, file, fmode);
 178        } else if (ceph_snap(inode) != CEPH_NOSNAP &&
 179                   (ci->i_snap_caps & wanted) == wanted) {
 180                __ceph_get_fmode(ci, fmode);
 181                spin_unlock(&ci->i_ceph_lock);
 182                return ceph_init_file(inode, file, fmode);
 183        }
 184        spin_unlock(&ci->i_ceph_lock);
 185
 186        dout("open fmode %d wants %s\n", fmode, ceph_cap_string(wanted));
 187        req = prepare_open_request(inode->i_sb, flags, 0);
 188        if (IS_ERR(req)) {
 189                err = PTR_ERR(req);
 190                goto out;
 191        }
 192        req->r_inode = inode;
 193        ihold(inode);
 194        req->r_num_caps = 1;
 195        if (flags & (O_CREAT|O_TRUNC))
 196                parent_inode = ceph_get_dentry_parent_inode(file->f_dentry);
 197        err = ceph_mdsc_do_request(mdsc, parent_inode, req);
 198        iput(parent_inode);
 199        if (!err)
 200                err = ceph_init_file(inode, file, req->r_fmode);
 201        ceph_mdsc_put_request(req);
 202        dout("open result=%d on %llx.%llx\n", err, ceph_vinop(inode));
 203out:
 204        return err;
 205}
 206
 207
 208/*
 209 * Do a lookup + open with a single request.  If we get a non-existent
 210 * file or symlink, return 1 so the VFS can retry.
 211 */
 212int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 213                     struct file *file, unsigned flags, umode_t mode,
 214                     int *opened)
 215{
 216        struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
 217        struct ceph_mds_client *mdsc = fsc->mdsc;
 218        struct ceph_mds_request *req;
 219        struct dentry *dn;
 220        int err;
 221
 222        dout("atomic_open %p dentry %p '%.*s' %s flags %d mode 0%o\n",
 223             dir, dentry, dentry->d_name.len, dentry->d_name.name,
 224             d_unhashed(dentry) ? "unhashed" : "hashed", flags, mode);
 225
 226        if (dentry->d_name.len > NAME_MAX)
 227                return -ENAMETOOLONG;
 228
 229        err = ceph_init_dentry(dentry);
 230        if (err < 0)
 231                return err;
 232
 233        /* do the open */
 234        req = prepare_open_request(dir->i_sb, flags, mode);
 235        if (IS_ERR(req))
 236                return PTR_ERR(req);
 237        req->r_dentry = dget(dentry);
 238        req->r_num_caps = 2;
 239        if (flags & O_CREAT) {
 240                req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
 241                req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
 242        }
 243        req->r_locked_dir = dir;           /* caller holds dir->i_mutex */
 244        err = ceph_mdsc_do_request(mdsc,
 245                                   (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
 246                                   req);
 247        if (err)
 248                goto out_err;
 249
 250        err = ceph_handle_snapdir(req, dentry, err);
 251        if (err == 0 && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
 252                err = ceph_handle_notrace_create(dir, dentry);
 253
 254        if (d_unhashed(dentry)) {
 255                dn = ceph_finish_lookup(req, dentry, err);
 256                if (IS_ERR(dn))
 257                        err = PTR_ERR(dn);
 258        } else {
 259                /* we were given a hashed negative dentry */
 260                dn = NULL;
 261        }
 262        if (err)
 263                goto out_err;
 264        if (dn || dentry->d_inode == NULL || S_ISLNK(dentry->d_inode->i_mode)) {
 265                /* make vfs retry on splice, ENOENT, or symlink */
 266                dout("atomic_open finish_no_open on dn %p\n", dn);
 267                err = finish_no_open(file, dn);
 268        } else {
 269                dout("atomic_open finish_open on dn %p\n", dn);
 270                if (req->r_op == CEPH_MDS_OP_CREATE && req->r_reply_info.has_create_ino) {
 271                        *opened |= FILE_CREATED;
 272                }
 273                err = finish_open(file, dentry, ceph_open, opened);
 274        }
 275
 276out_err:
 277        ceph_mdsc_put_request(req);
 278        dout("atomic_open result=%d\n", err);
 279        return err;
 280}
 281
 282int ceph_release(struct inode *inode, struct file *file)
 283{
 284        struct ceph_inode_info *ci = ceph_inode(inode);
 285        struct ceph_file_info *cf = file->private_data;
 286
 287        dout("release inode %p file %p\n", inode, file);
 288        ceph_put_fmode(ci, cf->fmode);
 289        if (cf->last_readdir)
 290                ceph_mdsc_put_request(cf->last_readdir);
 291        kfree(cf->last_name);
 292        kfree(cf->dir_info);
 293        dput(cf->dentry);
 294        kmem_cache_free(ceph_file_cachep, cf);
 295
 296        /* wake up anyone waiting for caps on this inode */
 297        wake_up_all(&ci->i_cap_wq);
 298        return 0;
 299}
 300
 301/*
 302 * Read a range of bytes striped over one or more objects.  Iterate over
 303 * objects we stripe over.  (That's not atomic, but good enough for now.)
 304 *
 305 * If we get a short result from the OSD, check against i_size; we need to
 306 * only return a short read to the caller if we hit EOF.
 307 */
 308static int striped_read(struct inode *inode,
 309                        u64 off, u64 len,
 310                        struct page **pages, int num_pages,
 311                        int *checkeof, bool o_direct,
 312                        unsigned long buf_align)
 313{
 314        struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 315        struct ceph_inode_info *ci = ceph_inode(inode);
 316        u64 pos, this_len;
 317        int io_align, page_align;
 318        int left, pages_left;
 319        int read;
 320        struct page **page_pos;
 321        int ret;
 322        bool hit_stripe, was_short;
 323
 324        /*
 325         * we may need to do multiple reads.  not atomic, unfortunately.
 326         */
 327        pos = off;
 328        left = len;
 329        page_pos = pages;
 330        pages_left = num_pages;
 331        read = 0;
 332        io_align = off & ~PAGE_MASK;
 333
 334more:
 335        if (o_direct)
 336                page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
 337        else
 338                page_align = pos & ~PAGE_MASK;
 339        this_len = left;
 340        ret = ceph_osdc_readpages(&fsc->client->osdc, ceph_vino(inode),
 341                                  &ci->i_layout, pos, &this_len,
 342                                  ci->i_truncate_seq,
 343                                  ci->i_truncate_size,
 344                                  page_pos, pages_left, page_align);
 345        if (ret == -ENOENT)
 346                ret = 0;
 347        hit_stripe = this_len < left;
 348        was_short = ret >= 0 && ret < this_len;
 349        dout("striped_read %llu~%u (read %u) got %d%s%s\n", pos, left, read,
 350             ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");
 351
 352        if (ret > 0) {
 353                int didpages = (page_align + ret) >> PAGE_CACHE_SHIFT;
 354
 355                if (read < pos - off) {
 356                        dout(" zero gap %llu to %llu\n", off + read, pos);
 357                        ceph_zero_page_vector_range(page_align + read,
 358                                                    pos - off - read, pages);
 359                }
 360                pos += ret;
 361                read = pos - off;
 362                left -= ret;
 363                page_pos += didpages;
 364                pages_left -= didpages;
 365
 366                /* hit stripe? */
 367                if (left && hit_stripe)
 368                        goto more;
 369        }
 370
 371        if (was_short) {
 372                /* did we bounce off eof? */
 373                if (pos + left > inode->i_size)
 374                        *checkeof = 1;
 375
 376                /* zero trailing bytes (inside i_size) */
 377                if (left > 0 && pos < inode->i_size) {
 378                        if (pos + left > inode->i_size)
 379                                left = inode->i_size - pos;
 380
 381                        dout("zero tail %d\n", left);
 382                        ceph_zero_page_vector_range(page_align + read, left,
 383                                                    pages);
 384                        read += left;
 385                }
 386        }
 387
 388        if (ret >= 0)
 389                ret = read;
 390        dout("striped_read returns %d\n", ret);
 391        return ret;
 392}
 393
 394/*
 395 * Completely synchronous read and write methods.  Direct from __user
 396 * buffer to osd, or directly to user pages (if O_DIRECT).
 397 *
 398 * If the read spans object boundary, just do multiple reads.
 399 */
 400static ssize_t ceph_sync_read(struct file *file, char __user *data,
 401                              unsigned len, loff_t *poff, int *checkeof)
 402{
 403        struct inode *inode = file_inode(file);
 404        struct page **pages;
 405        u64 off = *poff;
 406        int num_pages, ret;
 407
 408        dout("sync_read on file %p %llu~%u %s\n", file, off, len,
 409             (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
 410
 411        if (file->f_flags & O_DIRECT) {
 412                num_pages = calc_pages_for((unsigned long)data, len);
 413                pages = ceph_get_direct_page_vector(data, num_pages, true);
 414        } else {
 415                num_pages = calc_pages_for(off, len);
 416                pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
 417        }
 418        if (IS_ERR(pages))
 419                return PTR_ERR(pages);
 420
 421        /*
 422         * flush any page cache pages in this range.  this
 423         * will make concurrent normal and sync io slow,
 424         * but it will at least behave sensibly when they are
 425         * in sequence.
 426         */
 427        ret = filemap_write_and_wait(inode->i_mapping);
 428        if (ret < 0)
 429                goto done;
 430
 431        ret = striped_read(inode, off, len, pages, num_pages, checkeof,
 432                           file->f_flags & O_DIRECT,
 433                           (unsigned long)data & ~PAGE_MASK);
 434
 435        if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
 436                ret = ceph_copy_page_vector_to_user(pages, data, off, ret);
 437        if (ret >= 0)
 438                *poff = off + ret;
 439
 440done:
 441        if (file->f_flags & O_DIRECT)
 442                ceph_put_page_vector(pages, num_pages, true);
 443        else
 444                ceph_release_page_vector(pages, num_pages);
 445        dout("sync_read result %d\n", ret);
 446        return ret;
 447}
 448
 449/*
 450 * Write commit request unsafe callback, called to tell us when a
 451 * request is unsafe (that is, in flight--has been handed to the
 452 * messenger to send to its target osd).  It is called again when
 453 * we've received a response message indicating the request is
 454 * "safe" (its CEPH_OSD_FLAG_ONDISK flag is set), or when a request
 455 * is completed early (and unsuccessfully) due to a timeout or
 456 * interrupt.
 457 *
 458 * This is used if we requested both an ACK and ONDISK commit reply
 459 * from the OSD.
 460 */
 461static void ceph_sync_write_unsafe(struct ceph_osd_request *req, bool unsafe)
 462{
 463        struct ceph_inode_info *ci = ceph_inode(req->r_inode);
 464
 465        dout("%s %p tid %llu %ssafe\n", __func__, req, req->r_tid,
 466                unsafe ? "un" : "");
 467        if (unsafe) {
 468                ceph_get_cap_refs(ci, CEPH_CAP_FILE_WR);
 469                spin_lock(&ci->i_unsafe_lock);
 470                list_add_tail(&req->r_unsafe_item,
 471                              &ci->i_unsafe_writes);
 472                spin_unlock(&ci->i_unsafe_lock);
 473        } else {
 474                spin_lock(&ci->i_unsafe_lock);
 475                list_del_init(&req->r_unsafe_item);
 476                spin_unlock(&ci->i_unsafe_lock);
 477                ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
 478        }
 479}
 480
 481/*
 482 * Synchronous write, straight from __user pointer or user pages (if
 483 * O_DIRECT).
 484 *
 485 * If write spans object boundary, just do multiple writes.  (For a
 486 * correct atomic write, we should e.g. take write locks on all
 487 * objects, rollback on failure, etc.)
 488 */
 489static ssize_t ceph_sync_write(struct file *file, const char __user *data,
 490                               size_t left, loff_t pos, loff_t *ppos)
 491{
 492        struct inode *inode = file_inode(file);
 493        struct ceph_inode_info *ci = ceph_inode(inode);
 494        struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 495        struct ceph_snap_context *snapc;
 496        struct ceph_vino vino;
 497        struct ceph_osd_request *req;
 498        int num_ops = 1;
 499        struct page **pages;
 500        int num_pages;
 501        u64 len;
 502        int written = 0;
 503        int flags;
 504        int check_caps = 0;
 505        int page_align, io_align;
 506        unsigned long buf_align;
 507        int ret;
 508        struct timespec mtime = CURRENT_TIME;
 509        bool own_pages = false;
 510
 511        if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
 512                return -EROFS;
 513
 514        dout("sync_write on file %p %lld~%u %s\n", file, pos,
 515             (unsigned)left, (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
 516
 517        ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + left);
 518        if (ret < 0)
 519                return ret;
 520
 521        ret = invalidate_inode_pages2_range(inode->i_mapping,
 522                                            pos >> PAGE_CACHE_SHIFT,
 523                                            (pos + left) >> PAGE_CACHE_SHIFT);
 524        if (ret < 0)
 525                dout("invalidate_inode_pages2_range returned %d\n", ret);
 526
 527        flags = CEPH_OSD_FLAG_ORDERSNAP |
 528                CEPH_OSD_FLAG_ONDISK |
 529                CEPH_OSD_FLAG_WRITE;
 530        if ((file->f_flags & (O_SYNC|O_DIRECT)) == 0)
 531                flags |= CEPH_OSD_FLAG_ACK;
 532        else
 533                num_ops++;      /* Also include a 'startsync' command. */
 534
 535        /*
 536         * we may need to do multiple writes here if we span an object
 537         * boundary.  this isn't atomic, unfortunately.  :(
 538         */
 539more:
 540        io_align = pos & ~PAGE_MASK;
 541        buf_align = (unsigned long)data & ~PAGE_MASK;
 542        len = left;
 543
 544        snapc = ci->i_snap_realm->cached_context;
 545        vino = ceph_vino(inode);
 546        req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
 547                                    vino, pos, &len, num_ops,
 548                                    CEPH_OSD_OP_WRITE, flags, snapc,
 549                                    ci->i_truncate_seq, ci->i_truncate_size,
 550                                    false);
 551        if (IS_ERR(req))
 552                return PTR_ERR(req);
 553
 554        /* write from beginning of first page, regardless of io alignment */
 555        page_align = file->f_flags & O_DIRECT ? buf_align : io_align;
 556        num_pages = calc_pages_for(page_align, len);
 557        if (file->f_flags & O_DIRECT) {
 558                pages = ceph_get_direct_page_vector(data, num_pages, false);
 559                if (IS_ERR(pages)) {
 560                        ret = PTR_ERR(pages);
 561                        goto out;
 562                }
 563
 564                /*
 565                 * throw out any page cache pages in this range. this
 566                 * may block.
 567                 */
 568                truncate_inode_pages_range(inode->i_mapping, pos,
 569                                           (pos+len) | (PAGE_CACHE_SIZE-1));
 570        } else {
 571                pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
 572                if (IS_ERR(pages)) {
 573                        ret = PTR_ERR(pages);
 574                        goto out;
 575                }
 576                ret = ceph_copy_user_to_page_vector(pages, data, pos, len);
 577                if (ret < 0) {
 578                        ceph_release_page_vector(pages, num_pages);
 579                        goto out;
 580                }
 581
 582                if ((file->f_flags & O_SYNC) == 0) {
 583                        /* get a second commit callback */
 584                        req->r_unsafe_callback = ceph_sync_write_unsafe;
 585                        req->r_inode = inode;
 586                        own_pages = true;
 587                }
 588        }
 589        osd_req_op_extent_osd_data_pages(req, 0, pages, len, page_align,
 590                                        false, own_pages);
 591
 592        /* BUG_ON(vino.snap != CEPH_NOSNAP); */
 593        ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
 594
 595        ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
 596        if (!ret)
 597                ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
 598
 599        if (file->f_flags & O_DIRECT)
 600                ceph_put_page_vector(pages, num_pages, false);
 601        else if (file->f_flags & O_SYNC)
 602                ceph_release_page_vector(pages, num_pages);
 603
 604out:
 605        ceph_osdc_put_request(req);
 606        if (ret == 0) {
 607                pos += len;
 608                written += len;
 609                left -= len;
 610                data += len;
 611                if (left)
 612                        goto more;
 613
 614                ret = written;
 615                *ppos = pos;
 616                if (pos > i_size_read(inode))
 617                        check_caps = ceph_inode_set_size(inode, pos);
 618                if (check_caps)
 619                        ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY,
 620                                        NULL);
 621        }
 622        return ret;
 623}
 624
 625/*
 626 * Wrap generic_file_aio_read with checks for cap bits on the inode.
 627 * Atomically grab references, so that those bits are not released
 628 * back to the MDS mid-read.
 629 *
 630 * Hmm, the sync read case isn't actually async... should it be?
 631 */
 632static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
 633                             unsigned long nr_segs, loff_t pos)
 634{
 635        struct file *filp = iocb->ki_filp;
 636        struct ceph_file_info *fi = filp->private_data;
 637        loff_t *ppos = &iocb->ki_pos;
 638        size_t len = iov->iov_len;
 639        struct inode *inode = file_inode(filp);
 640        struct ceph_inode_info *ci = ceph_inode(inode);
 641        void __user *base = iov->iov_base;
 642        ssize_t ret;
 643        int want, got = 0;
 644        int checkeof = 0, read = 0;
 645
 646        dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
 647             inode, ceph_vinop(inode), pos, (unsigned)len, inode);
 648again:
 649        if (fi->fmode & CEPH_FILE_MODE_LAZY)
 650                want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
 651        else
 652                want = CEPH_CAP_FILE_CACHE;
 653        ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
 654        if (ret < 0)
 655                goto out;
 656        dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
 657             inode, ceph_vinop(inode), pos, (unsigned)len,
 658             ceph_cap_string(got));
 659
 660        if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
 661            (iocb->ki_filp->f_flags & O_DIRECT) ||
 662            (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
 663            (fi->flags & CEPH_F_SYNC))
 664                /* hmm, this isn't really async... */
 665                ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
 666        else
 667                ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
 668
 669out:
 670        dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
 671             inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
 672        ceph_put_cap_refs(ci, got);
 673
 674        if (checkeof && ret >= 0) {
 675                int statret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
 676
 677                /* hit EOF or hole? */
 678                if (statret == 0 && *ppos < inode->i_size) {
 679                        dout("aio_read sync_read hit hole, ppos %lld < size %lld, reading more\n", *ppos, inode->i_size);
 680                        read += ret;
 681                        base += ret;
 682                        len -= ret;
 683                        checkeof = 0;
 684                        goto again;
 685                }
 686        }
 687        if (ret >= 0)
 688                ret += read;
 689
 690        return ret;
 691}
 692
 693/*
 694 * Take cap references to avoid releasing caps to MDS mid-write.
 695 *
 696 * If we are synchronous, and write with an old snap context, the OSD
 697 * may return EOLDSNAPC.  In that case, retry the write.. _after_
 698 * dropping our cap refs and allowing the pending snap to logically
 699 * complete _before_ this write occurs.
 700 *
 701 * If we are near ENOSPC, write synchronously.
 702 */
 703static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
 704                       unsigned long nr_segs, loff_t pos)
 705{
 706        struct file *file = iocb->ki_filp;
 707        struct ceph_file_info *fi = file->private_data;
 708        struct inode *inode = file_inode(file);
 709        struct ceph_inode_info *ci = ceph_inode(inode);
 710        struct ceph_osd_client *osdc =
 711                &ceph_sb_to_client(inode->i_sb)->client->osdc;
 712        ssize_t count, written = 0;
 713        int err, want, got;
 714        bool hold_mutex;
 715
 716        if (ceph_snap(inode) != CEPH_NOSNAP)
 717                return -EROFS;
 718
 719        mutex_lock(&inode->i_mutex);
 720        hold_mutex = true;
 721
 722        err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
 723        if (err)
 724                goto out;
 725
 726        /* We can write back this queue in page reclaim */
 727        current->backing_dev_info = file->f_mapping->backing_dev_info;
 728
 729        err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 730        if (err)
 731                goto out;
 732
 733        if (count == 0)
 734                goto out;
 735
 736        err = file_remove_suid(file);
 737        if (err)
 738                goto out;
 739
 740        err = file_update_time(file);
 741        if (err)
 742                goto out;
 743
 744retry_snap:
 745        if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL)) {
 746                err = -ENOSPC;
 747                goto out;
 748        }
 749
 750        dout("aio_write %p %llx.%llx %llu~%zd getting caps. i_size %llu\n",
 751             inode, ceph_vinop(inode), pos, count, inode->i_size);
 752        if (fi->fmode & CEPH_FILE_MODE_LAZY)
 753                want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
 754        else
 755                want = CEPH_CAP_FILE_BUFFER;
 756        got = 0;
 757        err = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, pos + count);
 758        if (err < 0)
 759                goto out;
 760
 761        dout("aio_write %p %llx.%llx %llu~%zd got cap refs on %s\n",
 762             inode, ceph_vinop(inode), pos, count, ceph_cap_string(got));
 763
 764        if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
 765            (iocb->ki_filp->f_flags & O_DIRECT) ||
 766            (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
 767            (fi->flags & CEPH_F_SYNC)) {
 768                mutex_unlock(&inode->i_mutex);
 769                written = ceph_sync_write(file, iov->iov_base, count,
 770                                          pos, &iocb->ki_pos);
 771        } else {
 772                written = generic_file_buffered_write(iocb, iov, nr_segs,
 773                                                      pos, &iocb->ki_pos,
 774                                                      count, 0);
 775                mutex_unlock(&inode->i_mutex);
 776        }
 777        hold_mutex = false;
 778
 779        if (written >= 0) {
 780                int dirty;
 781                spin_lock(&ci->i_ceph_lock);
 782                dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
 783                spin_unlock(&ci->i_ceph_lock);
 784                if (dirty)
 785                        __mark_inode_dirty(inode, dirty);
 786        }
 787
 788        dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
 789             inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
 790             ceph_cap_string(got));
 791        ceph_put_cap_refs(ci, got);
 792
 793        if (written >= 0 &&
 794            ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host) ||
 795             ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
 796                err = vfs_fsync_range(file, pos, pos + written - 1, 1);
 797                if (err < 0)
 798                        written = err;
 799        }
 800
 801        if (written == -EOLDSNAPC) {
 802                dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",
 803                     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len);
 804                mutex_lock(&inode->i_mutex);
 805                hold_mutex = true;
 806                goto retry_snap;
 807        }
 808out:
 809        if (hold_mutex)
 810                mutex_unlock(&inode->i_mutex);
 811        current->backing_dev_info = NULL;
 812
 813        return written ? written : err;
 814}
 815
 816/*
 817 * llseek.  be sure to verify file size on SEEK_END.
 818 */
 819static loff_t ceph_llseek(struct file *file, loff_t offset, int whence)
 820{
 821        struct inode *inode = file->f_mapping->host;
 822        int ret;
 823
 824        mutex_lock(&inode->i_mutex);
 825        __ceph_do_pending_vmtruncate(inode);
 826
 827        if (whence == SEEK_END || whence == SEEK_DATA || whence == SEEK_HOLE) {
 828                ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
 829                if (ret < 0) {
 830                        offset = ret;
 831                        goto out;
 832                }
 833        }
 834
 835        switch (whence) {
 836        case SEEK_END:
 837                offset += inode->i_size;
 838                break;
 839        case SEEK_CUR:
 840                /*
 841                 * Here we special-case the lseek(fd, 0, SEEK_CUR)
 842                 * position-querying operation.  Avoid rewriting the "same"
 843                 * f_pos value back to the file because a concurrent read(),
 844                 * write() or lseek() might have altered it
 845                 */
 846                if (offset == 0) {
 847                        offset = file->f_pos;
 848                        goto out;
 849                }
 850                offset += file->f_pos;
 851                break;
 852        case SEEK_DATA:
 853                if (offset >= inode->i_size) {
 854                        ret = -ENXIO;
 855                        goto out;
 856                }
 857                break;
 858        case SEEK_HOLE:
 859                if (offset >= inode->i_size) {
 860                        ret = -ENXIO;
 861                        goto out;
 862                }
 863                offset = inode->i_size;
 864                break;
 865        }
 866
 867        offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
 868
 869out:
 870        mutex_unlock(&inode->i_mutex);
 871        return offset;
 872}
 873
 874const struct file_operations ceph_file_fops = {
 875        .open = ceph_open,
 876        .release = ceph_release,
 877        .llseek = ceph_llseek,
 878        .read = do_sync_read,
 879        .write = do_sync_write,
 880        .aio_read = ceph_aio_read,
 881        .aio_write = ceph_aio_write,
 882        .mmap = ceph_mmap,
 883        .fsync = ceph_fsync,
 884        .lock = ceph_lock,
 885        .flock = ceph_flock,
 886        .splice_read = generic_file_splice_read,
 887        .splice_write = generic_file_splice_write,
 888        .unlocked_ioctl = ceph_ioctl,
 889        .compat_ioctl   = ceph_ioctl,
 890};
 891
 892
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