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TOMOYO Linux Cross Reference
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  */
 41 static struct ceph_mds_request *
 42 prepare_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);
 59 out:
 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  */
 67 static 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  */
116 int 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));
203 out:
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  */
212 int 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 
276 out_err:
277         ceph_mdsc_put_request(req);
278         dout("atomic_open result=%d\n", err);
279         return err;
280 }
281 
282 int 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  */
308 static 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, left;
317         int io_align, page_align;
318         int 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 
334 more:
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~%llu (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;
354                 if (was_short && (pos + ret < inode->i_size)) {
355                         u64 tmp = min(this_len - ret,
356                                         inode->i_size - pos - ret);
357                         dout(" zero gap %llu to %llu\n",
358                                 pos + ret, pos + ret + tmp);
359                         ceph_zero_page_vector_range(page_align + read + ret,
360                                                         tmp, pages);
361                         ret += tmp;
362                 }
363 
364                 didpages = (page_align + ret) >> PAGE_CACHE_SHIFT;
365                 pos += ret;
366                 read = pos - off;
367                 left -= ret;
368                 page_pos += didpages;
369                 pages_left -= didpages;
370 
371                 /* hit stripe and need continue*/
372                 if (left && hit_stripe && pos < inode->i_size)
373                         goto more;
374         }
375 
376         if (read > 0) {
377                 ret = read;
378                 /* did we bounce off eof? */
379                 if (pos + left > inode->i_size)
380                         *checkeof = 1;
381         }
382 
383         dout("striped_read returns %d\n", ret);
384         return ret;
385 }
386 
387 /*
388  * Completely synchronous read and write methods.  Direct from __user
389  * buffer to osd, or directly to user pages (if O_DIRECT).
390  *
391  * If the read spans object boundary, just do multiple reads.
392  */
393 static ssize_t ceph_sync_read(struct file *file, char __user *data,
394                               unsigned len, loff_t *poff, int *checkeof)
395 {
396         struct inode *inode = file_inode(file);
397         struct page **pages;
398         u64 off = *poff;
399         int num_pages, ret;
400 
401         dout("sync_read on file %p %llu~%u %s\n", file, off, len,
402              (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
403 
404         if (file->f_flags & O_DIRECT) {
405                 num_pages = calc_pages_for((unsigned long)data, len);
406                 pages = ceph_get_direct_page_vector(data, num_pages, true);
407         } else {
408                 num_pages = calc_pages_for(off, len);
409                 pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
410         }
411         if (IS_ERR(pages))
412                 return PTR_ERR(pages);
413 
414         /*
415          * flush any page cache pages in this range.  this
416          * will make concurrent normal and sync io slow,
417          * but it will at least behave sensibly when they are
418          * in sequence.
419          */
420         ret = filemap_write_and_wait(inode->i_mapping);
421         if (ret < 0)
422                 goto done;
423 
424         ret = striped_read(inode, off, len, pages, num_pages, checkeof,
425                            file->f_flags & O_DIRECT,
426                            (unsigned long)data & ~PAGE_MASK);
427 
428         if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
429                 ret = ceph_copy_page_vector_to_user(pages, data, off, ret);
430         if (ret >= 0)
431                 *poff = off + ret;
432 
433 done:
434         if (file->f_flags & O_DIRECT)
435                 ceph_put_page_vector(pages, num_pages, true);
436         else
437                 ceph_release_page_vector(pages, num_pages);
438         dout("sync_read result %d\n", ret);
439         return ret;
440 }
441 
442 /*
443  * Write commit request unsafe callback, called to tell us when a
444  * request is unsafe (that is, in flight--has been handed to the
445  * messenger to send to its target osd).  It is called again when
446  * we've received a response message indicating the request is
447  * "safe" (its CEPH_OSD_FLAG_ONDISK flag is set), or when a request
448  * is completed early (and unsuccessfully) due to a timeout or
449  * interrupt.
450  *
451  * This is used if we requested both an ACK and ONDISK commit reply
452  * from the OSD.
453  */
454 static void ceph_sync_write_unsafe(struct ceph_osd_request *req, bool unsafe)
455 {
456         struct ceph_inode_info *ci = ceph_inode(req->r_inode);
457 
458         dout("%s %p tid %llu %ssafe\n", __func__, req, req->r_tid,
459                 unsafe ? "un" : "");
460         if (unsafe) {
461                 ceph_get_cap_refs(ci, CEPH_CAP_FILE_WR);
462                 spin_lock(&ci->i_unsafe_lock);
463                 list_add_tail(&req->r_unsafe_item,
464                               &ci->i_unsafe_writes);
465                 spin_unlock(&ci->i_unsafe_lock);
466         } else {
467                 spin_lock(&ci->i_unsafe_lock);
468                 list_del_init(&req->r_unsafe_item);
469                 spin_unlock(&ci->i_unsafe_lock);
470                 ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
471         }
472 }
473 
474 /*
475  * Synchronous write, straight from __user pointer or user pages (if
476  * O_DIRECT).
477  *
478  * If write spans object boundary, just do multiple writes.  (For a
479  * correct atomic write, we should e.g. take write locks on all
480  * objects, rollback on failure, etc.)
481  */
482 static ssize_t ceph_sync_write(struct file *file, const char __user *data,
483                                size_t left, loff_t pos, loff_t *ppos)
484 {
485         struct inode *inode = file_inode(file);
486         struct ceph_inode_info *ci = ceph_inode(inode);
487         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
488         struct ceph_snap_context *snapc;
489         struct ceph_vino vino;
490         struct ceph_osd_request *req;
491         int num_ops = 1;
492         struct page **pages;
493         int num_pages;
494         u64 len;
495         int written = 0;
496         int flags;
497         int check_caps = 0;
498         int page_align, io_align;
499         unsigned long buf_align;
500         int ret;
501         struct timespec mtime = CURRENT_TIME;
502         bool own_pages = false;
503 
504         if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
505                 return -EROFS;
506 
507         dout("sync_write on file %p %lld~%u %s\n", file, pos,
508              (unsigned)left, (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
509 
510         ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + left);
511         if (ret < 0)
512                 return ret;
513 
514         ret = invalidate_inode_pages2_range(inode->i_mapping,
515                                             pos >> PAGE_CACHE_SHIFT,
516                                             (pos + left) >> PAGE_CACHE_SHIFT);
517         if (ret < 0)
518                 dout("invalidate_inode_pages2_range returned %d\n", ret);
519 
520         flags = CEPH_OSD_FLAG_ORDERSNAP |
521                 CEPH_OSD_FLAG_ONDISK |
522                 CEPH_OSD_FLAG_WRITE;
523         if ((file->f_flags & (O_SYNC|O_DIRECT)) == 0)
524                 flags |= CEPH_OSD_FLAG_ACK;
525         else
526                 num_ops++;      /* Also include a 'startsync' command. */
527 
528         /*
529          * we may need to do multiple writes here if we span an object
530          * boundary.  this isn't atomic, unfortunately.  :(
531          */
532 more:
533         io_align = pos & ~PAGE_MASK;
534         buf_align = (unsigned long)data & ~PAGE_MASK;
535         len = left;
536 
537         snapc = ci->i_snap_realm->cached_context;
538         vino = ceph_vino(inode);
539         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
540                                     vino, pos, &len, num_ops,
541                                     CEPH_OSD_OP_WRITE, flags, snapc,
542                                     ci->i_truncate_seq, ci->i_truncate_size,
543                                     false);
544         if (IS_ERR(req))
545                 return PTR_ERR(req);
546 
547         /* write from beginning of first page, regardless of io alignment */
548         page_align = file->f_flags & O_DIRECT ? buf_align : io_align;
549         num_pages = calc_pages_for(page_align, len);
550         if (file->f_flags & O_DIRECT) {
551                 pages = ceph_get_direct_page_vector(data, num_pages, false);
552                 if (IS_ERR(pages)) {
553                         ret = PTR_ERR(pages);
554                         goto out;
555                 }
556 
557                 /*
558                  * throw out any page cache pages in this range. this
559                  * may block.
560                  */
561                 truncate_inode_pages_range(inode->i_mapping, pos,
562                                            (pos+len) | (PAGE_CACHE_SIZE-1));
563         } else {
564                 pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
565                 if (IS_ERR(pages)) {
566                         ret = PTR_ERR(pages);
567                         goto out;
568                 }
569                 ret = ceph_copy_user_to_page_vector(pages, data, pos, len);
570                 if (ret < 0) {
571                         ceph_release_page_vector(pages, num_pages);
572                         goto out;
573                 }
574 
575                 if ((file->f_flags & O_SYNC) == 0) {
576                         /* get a second commit callback */
577                         req->r_unsafe_callback = ceph_sync_write_unsafe;
578                         req->r_inode = inode;
579                         own_pages = true;
580                 }
581         }
582         osd_req_op_extent_osd_data_pages(req, 0, pages, len, page_align,
583                                         false, own_pages);
584 
585         /* BUG_ON(vino.snap != CEPH_NOSNAP); */
586         ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
587 
588         ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
589         if (!ret)
590                 ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
591 
592         if (file->f_flags & O_DIRECT)
593                 ceph_put_page_vector(pages, num_pages, false);
594         else if (file->f_flags & O_SYNC)
595                 ceph_release_page_vector(pages, num_pages);
596 
597 out:
598         ceph_osdc_put_request(req);
599         if (ret == 0) {
600                 pos += len;
601                 written += len;
602                 left -= len;
603                 data += len;
604                 if (left)
605                         goto more;
606 
607                 ret = written;
608                 *ppos = pos;
609                 if (pos > i_size_read(inode))
610                         check_caps = ceph_inode_set_size(inode, pos);
611                 if (check_caps)
612                         ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY,
613                                         NULL);
614         } else if (ret != -EOLDSNAPC && written > 0) {
615                 ret = written;
616         }
617         return ret;
618 }
619 
620 /*
621  * Wrap generic_file_aio_read with checks for cap bits on the inode.
622  * Atomically grab references, so that those bits are not released
623  * back to the MDS mid-read.
624  *
625  * Hmm, the sync read case isn't actually async... should it be?
626  */
627 static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
628                              unsigned long nr_segs, loff_t pos)
629 {
630         struct file *filp = iocb->ki_filp;
631         struct ceph_file_info *fi = filp->private_data;
632         loff_t *ppos = &iocb->ki_pos;
633         size_t len = iov->iov_len;
634         struct inode *inode = file_inode(filp);
635         struct ceph_inode_info *ci = ceph_inode(inode);
636         void __user *base = iov->iov_base;
637         ssize_t ret;
638         int want, got = 0;
639         int checkeof = 0, read = 0;
640 
641         dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
642              inode, ceph_vinop(inode), pos, (unsigned)len, inode);
643 again:
644         if (fi->fmode & CEPH_FILE_MODE_LAZY)
645                 want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
646         else
647                 want = CEPH_CAP_FILE_CACHE;
648         ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
649         if (ret < 0)
650                 goto out;
651         dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
652              inode, ceph_vinop(inode), pos, (unsigned)len,
653              ceph_cap_string(got));
654 
655         if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
656             (iocb->ki_filp->f_flags & O_DIRECT) ||
657             (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
658             (fi->flags & CEPH_F_SYNC))
659                 /* hmm, this isn't really async... */
660                 ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
661         else
662                 ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
663 
664 out:
665         dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
666              inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
667         ceph_put_cap_refs(ci, got);
668 
669         if (checkeof && ret >= 0) {
670                 int statret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
671 
672                 /* hit EOF or hole? */
673                 if (statret == 0 && *ppos < inode->i_size) {
674                         dout("aio_read sync_read hit hole, ppos %lld < size %lld, reading more\n", *ppos, inode->i_size);
675                         read += ret;
676                         base += ret;
677                         len -= ret;
678                         checkeof = 0;
679                         goto again;
680                 }
681         }
682         if (ret >= 0)
683                 ret += read;
684 
685         return ret;
686 }
687 
688 /*
689  * Take cap references to avoid releasing caps to MDS mid-write.
690  *
691  * If we are synchronous, and write with an old snap context, the OSD
692  * may return EOLDSNAPC.  In that case, retry the write.. _after_
693  * dropping our cap refs and allowing the pending snap to logically
694  * complete _before_ this write occurs.
695  *
696  * If we are near ENOSPC, write synchronously.
697  */
698 static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
699                        unsigned long nr_segs, loff_t pos)
700 {
701         struct file *file = iocb->ki_filp;
702         struct ceph_file_info *fi = file->private_data;
703         struct inode *inode = file_inode(file);
704         struct ceph_inode_info *ci = ceph_inode(inode);
705         struct ceph_osd_client *osdc =
706                 &ceph_sb_to_client(inode->i_sb)->client->osdc;
707         ssize_t count, written = 0;
708         int err, want, got;
709         bool hold_mutex;
710 
711         if (ceph_snap(inode) != CEPH_NOSNAP)
712                 return -EROFS;
713 
714         sb_start_write(inode->i_sb);
715         mutex_lock(&inode->i_mutex);
716         hold_mutex = true;
717 
718         err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
719         if (err)
720                 goto out;
721 
722         /* We can write back this queue in page reclaim */
723         current->backing_dev_info = file->f_mapping->backing_dev_info;
724 
725         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
726         if (err)
727                 goto out;
728 
729         if (count == 0)
730                 goto out;
731 
732         err = file_remove_suid(file);
733         if (err)
734                 goto out;
735 
736         err = file_update_time(file);
737         if (err)
738                 goto out;
739 
740 retry_snap:
741         if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL)) {
742                 err = -ENOSPC;
743                 goto out;
744         }
745 
746         dout("aio_write %p %llx.%llx %llu~%zd getting caps. i_size %llu\n",
747              inode, ceph_vinop(inode), pos, count, inode->i_size);
748         if (fi->fmode & CEPH_FILE_MODE_LAZY)
749                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
750         else
751                 want = CEPH_CAP_FILE_BUFFER;
752         got = 0;
753         err = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, pos + count);
754         if (err < 0)
755                 goto out;
756 
757         dout("aio_write %p %llx.%llx %llu~%zd got cap refs on %s\n",
758              inode, ceph_vinop(inode), pos, count, ceph_cap_string(got));
759 
760         if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
761             (iocb->ki_filp->f_flags & O_DIRECT) ||
762             (inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
763             (fi->flags & CEPH_F_SYNC)) {
764                 mutex_unlock(&inode->i_mutex);
765                 written = ceph_sync_write(file, iov->iov_base, count,
766                                           pos, &iocb->ki_pos);
767         } else {
768                 written = generic_file_buffered_write(iocb, iov, nr_segs,
769                                                       pos, &iocb->ki_pos,
770                                                       count, 0);
771                 mutex_unlock(&inode->i_mutex);
772         }
773         hold_mutex = false;
774 
775         if (written >= 0) {
776                 int dirty;
777                 spin_lock(&ci->i_ceph_lock);
778                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
779                 spin_unlock(&ci->i_ceph_lock);
780                 if (dirty)
781                         __mark_inode_dirty(inode, dirty);
782         }
783 
784         dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
785              inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
786              ceph_cap_string(got));
787         ceph_put_cap_refs(ci, got);
788 
789         if (written >= 0 &&
790             ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host) ||
791              ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
792                 err = vfs_fsync_range(file, pos, pos + written - 1, 1);
793                 if (err < 0)
794                         written = err;
795         }
796 
797         if (written == -EOLDSNAPC) {
798                 dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",
799                      inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len);
800                 mutex_lock(&inode->i_mutex);
801                 hold_mutex = true;
802                 goto retry_snap;
803         }
804 out:
805         if (hold_mutex)
806                 mutex_unlock(&inode->i_mutex);
807         sb_end_write(inode->i_sb);
808         current->backing_dev_info = NULL;
809 
810         return written ? written : err;
811 }
812 
813 /*
814  * llseek.  be sure to verify file size on SEEK_END.
815  */
816 static loff_t ceph_llseek(struct file *file, loff_t offset, int whence)
817 {
818         struct inode *inode = file->f_mapping->host;
819         int ret;
820 
821         mutex_lock(&inode->i_mutex);
822         __ceph_do_pending_vmtruncate(inode, false);
823 
824         if (whence == SEEK_END || whence == SEEK_DATA || whence == SEEK_HOLE) {
825                 ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
826                 if (ret < 0) {
827                         offset = ret;
828                         goto out;
829                 }
830         }
831 
832         switch (whence) {
833         case SEEK_END:
834                 offset += inode->i_size;
835                 break;
836         case SEEK_CUR:
837                 /*
838                  * Here we special-case the lseek(fd, 0, SEEK_CUR)
839                  * position-querying operation.  Avoid rewriting the "same"
840                  * f_pos value back to the file because a concurrent read(),
841                  * write() or lseek() might have altered it
842                  */
843                 if (offset == 0) {
844                         offset = file->f_pos;
845                         goto out;
846                 }
847                 offset += file->f_pos;
848                 break;
849         case SEEK_DATA:
850                 if (offset >= inode->i_size) {
851                         ret = -ENXIO;
852                         goto out;
853                 }
854                 break;
855         case SEEK_HOLE:
856                 if (offset >= inode->i_size) {
857                         ret = -ENXIO;
858                         goto out;
859                 }
860                 offset = inode->i_size;
861                 break;
862         }
863 
864         if (offset < 0 || offset > inode->i_sb->s_maxbytes) {
865                 offset = -EINVAL;
866                 goto out;
867         }
868 
869         /* Special lock needed here? */
870         if (offset != file->f_pos) {
871                 file->f_pos = offset;
872                 file->f_version = 0;
873         }
874 
875 out:
876         mutex_unlock(&inode->i_mutex);
877         return offset;
878 }
879 
880 const struct file_operations ceph_file_fops = {
881         .open = ceph_open,
882         .release = ceph_release,
883         .llseek = ceph_llseek,
884         .read = do_sync_read,
885         .write = do_sync_write,
886         .aio_read = ceph_aio_read,
887         .aio_write = ceph_aio_write,
888         .mmap = ceph_mmap,
889         .fsync = ceph_fsync,
890         .lock = ceph_lock,
891         .flock = ceph_flock,
892         .splice_read = generic_file_splice_read,
893         .splice_write = generic_file_splice_write,
894         .unlocked_ioctl = ceph_ioctl,
895         .compat_ioctl   = ceph_ioctl,
896 };
897 
898 

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