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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 #include <linux/falloc.h>
 12 
 13 #include "super.h"
 14 #include "mds_client.h"
 15 #include "cache.h"
 16 
 17 /*
 18  * Ceph file operations
 19  *
 20  * Implement basic open/close functionality, and implement
 21  * read/write.
 22  *
 23  * We implement three modes of file I/O:
 24  *  - buffered uses the generic_file_aio_{read,write} helpers
 25  *
 26  *  - synchronous is used when there is multi-client read/write
 27  *    sharing, avoids the page cache, and synchronously waits for an
 28  *    ack from the OSD.
 29  *
 30  *  - direct io takes the variant of the sync path that references
 31  *    user pages directly.
 32  *
 33  * fsync() flushes and waits on dirty pages, but just queues metadata
 34  * for writeback: since the MDS can recover size and mtime there is no
 35  * need to wait for MDS acknowledgement.
 36  */
 37 
 38 
 39 /*
 40  * Prepare an open request.  Preallocate ceph_cap to avoid an
 41  * inopportune ENOMEM later.
 42  */
 43 static struct ceph_mds_request *
 44 prepare_open_request(struct super_block *sb, int flags, int create_mode)
 45 {
 46         struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
 47         struct ceph_mds_client *mdsc = fsc->mdsc;
 48         struct ceph_mds_request *req;
 49         int want_auth = USE_ANY_MDS;
 50         int op = (flags & O_CREAT) ? CEPH_MDS_OP_CREATE : CEPH_MDS_OP_OPEN;
 51 
 52         if (flags & (O_WRONLY|O_RDWR|O_CREAT|O_TRUNC))
 53                 want_auth = USE_AUTH_MDS;
 54 
 55         req = ceph_mdsc_create_request(mdsc, op, want_auth);
 56         if (IS_ERR(req))
 57                 goto out;
 58         req->r_fmode = ceph_flags_to_mode(flags);
 59         req->r_args.open.flags = cpu_to_le32(flags);
 60         req->r_args.open.mode = cpu_to_le32(create_mode);
 61 out:
 62         return req;
 63 }
 64 
 65 /*
 66  * initialize private struct file data.
 67  * if we fail, clean up by dropping fmode reference on the ceph_inode
 68  */
 69 static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
 70 {
 71         struct ceph_file_info *cf;
 72         int ret = 0;
 73         struct ceph_inode_info *ci = ceph_inode(inode);
 74         struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
 75         struct ceph_mds_client *mdsc = fsc->mdsc;
 76 
 77         switch (inode->i_mode & S_IFMT) {
 78         case S_IFREG:
 79                 /* First file open request creates the cookie, we want to keep
 80                  * this cookie around for the filetime of the inode as not to
 81                  * have to worry about fscache register / revoke / operation
 82                  * races.
 83                  *
 84                  * Also, if we know the operation is going to invalidate data
 85                  * (non readonly) just nuke the cache right away.
 86                  */
 87                 ceph_fscache_register_inode_cookie(mdsc->fsc, ci);
 88                 if ((fmode & CEPH_FILE_MODE_WR))
 89                         ceph_fscache_invalidate(inode);
 90         case S_IFDIR:
 91                 dout("init_file %p %p 0%o (regular)\n", inode, file,
 92                      inode->i_mode);
 93                 cf = kmem_cache_alloc(ceph_file_cachep, GFP_NOFS | __GFP_ZERO);
 94                 if (cf == NULL) {
 95                         ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
 96                         return -ENOMEM;
 97                 }
 98                 cf->fmode = fmode;
 99                 cf->next_offset = 2;
100                 file->private_data = cf;
101                 BUG_ON(inode->i_fop->release != ceph_release);
102                 break;
103 
104         case S_IFLNK:
105                 dout("init_file %p %p 0%o (symlink)\n", inode, file,
106                      inode->i_mode);
107                 ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
108                 break;
109 
110         default:
111                 dout("init_file %p %p 0%o (special)\n", inode, file,
112                      inode->i_mode);
113                 /*
114                  * we need to drop the open ref now, since we don't
115                  * have .release set to ceph_release.
116                  */
117                 ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
118                 BUG_ON(inode->i_fop->release == ceph_release);
119 
120                 /* call the proper open fop */
121                 ret = inode->i_fop->open(inode, file);
122         }
123         return ret;
124 }
125 
126 /*
127  * If we already have the requisite capabilities, we can satisfy
128  * the open request locally (no need to request new caps from the
129  * MDS).  We do, however, need to inform the MDS (asynchronously)
130  * if our wanted caps set expands.
131  */
132 int ceph_open(struct inode *inode, struct file *file)
133 {
134         struct ceph_inode_info *ci = ceph_inode(inode);
135         struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
136         struct ceph_mds_client *mdsc = fsc->mdsc;
137         struct ceph_mds_request *req;
138         struct ceph_file_info *cf = file->private_data;
139         struct inode *parent_inode = NULL;
140         int err;
141         int flags, fmode, wanted;
142 
143         if (cf) {
144                 dout("open file %p is already opened\n", file);
145                 return 0;
146         }
147 
148         /* filter out O_CREAT|O_EXCL; vfs did that already.  yuck. */
149         flags = file->f_flags & ~(O_CREAT|O_EXCL);
150         if (S_ISDIR(inode->i_mode))
151                 flags = O_DIRECTORY;  /* mds likes to know */
152 
153         dout("open inode %p ino %llx.%llx file %p flags %d (%d)\n", inode,
154              ceph_vinop(inode), file, flags, file->f_flags);
155         fmode = ceph_flags_to_mode(flags);
156         wanted = ceph_caps_for_mode(fmode);
157 
158         /* snapped files are read-only */
159         if (ceph_snap(inode) != CEPH_NOSNAP && (file->f_mode & FMODE_WRITE))
160                 return -EROFS;
161 
162         /* trivially open snapdir */
163         if (ceph_snap(inode) == CEPH_SNAPDIR) {
164                 spin_lock(&ci->i_ceph_lock);
165                 __ceph_get_fmode(ci, fmode);
166                 spin_unlock(&ci->i_ceph_lock);
167                 return ceph_init_file(inode, file, fmode);
168         }
169 
170         /*
171          * No need to block if we have caps on the auth MDS (for
172          * write) or any MDS (for read).  Update wanted set
173          * asynchronously.
174          */
175         spin_lock(&ci->i_ceph_lock);
176         if (__ceph_is_any_real_caps(ci) &&
177             (((fmode & CEPH_FILE_MODE_WR) == 0) || ci->i_auth_cap)) {
178                 int mds_wanted = __ceph_caps_mds_wanted(ci);
179                 int issued = __ceph_caps_issued(ci, NULL);
180 
181                 dout("open %p fmode %d want %s issued %s using existing\n",
182                      inode, fmode, ceph_cap_string(wanted),
183                      ceph_cap_string(issued));
184                 __ceph_get_fmode(ci, fmode);
185                 spin_unlock(&ci->i_ceph_lock);
186 
187                 /* adjust wanted? */
188                 if ((issued & wanted) != wanted &&
189                     (mds_wanted & wanted) != wanted &&
190                     ceph_snap(inode) != CEPH_SNAPDIR)
191                         ceph_check_caps(ci, 0, NULL);
192 
193                 return ceph_init_file(inode, file, fmode);
194         } else if (ceph_snap(inode) != CEPH_NOSNAP &&
195                    (ci->i_snap_caps & wanted) == wanted) {
196                 __ceph_get_fmode(ci, fmode);
197                 spin_unlock(&ci->i_ceph_lock);
198                 return ceph_init_file(inode, file, fmode);
199         }
200 
201         spin_unlock(&ci->i_ceph_lock);
202 
203         dout("open fmode %d wants %s\n", fmode, ceph_cap_string(wanted));
204         req = prepare_open_request(inode->i_sb, flags, 0);
205         if (IS_ERR(req)) {
206                 err = PTR_ERR(req);
207                 goto out;
208         }
209         req->r_inode = inode;
210         ihold(inode);
211 
212         req->r_num_caps = 1;
213         if (flags & (O_CREAT|O_TRUNC))
214                 parent_inode = ceph_get_dentry_parent_inode(file->f_dentry);
215         err = ceph_mdsc_do_request(mdsc, parent_inode, req);
216         iput(parent_inode);
217         if (!err)
218                 err = ceph_init_file(inode, file, req->r_fmode);
219         ceph_mdsc_put_request(req);
220         dout("open result=%d on %llx.%llx\n", err, ceph_vinop(inode));
221 out:
222         return err;
223 }
224 
225 
226 /*
227  * Do a lookup + open with a single request.  If we get a non-existent
228  * file or symlink, return 1 so the VFS can retry.
229  */
230 int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
231                      struct file *file, unsigned flags, umode_t mode,
232                      int *opened)
233 {
234         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
235         struct ceph_mds_client *mdsc = fsc->mdsc;
236         struct ceph_mds_request *req;
237         struct dentry *dn;
238         int err;
239 
240         dout("atomic_open %p dentry %p '%.*s' %s flags %d mode 0%o\n",
241              dir, dentry, dentry->d_name.len, dentry->d_name.name,
242              d_unhashed(dentry) ? "unhashed" : "hashed", flags, mode);
243 
244         if (dentry->d_name.len > NAME_MAX)
245                 return -ENAMETOOLONG;
246 
247         err = ceph_init_dentry(dentry);
248         if (err < 0)
249                 return err;
250 
251         /* do the open */
252         req = prepare_open_request(dir->i_sb, flags, mode);
253         if (IS_ERR(req))
254                 return PTR_ERR(req);
255         req->r_dentry = dget(dentry);
256         req->r_num_caps = 2;
257         if (flags & O_CREAT) {
258                 req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
259                 req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
260         }
261         req->r_locked_dir = dir;           /* caller holds dir->i_mutex */
262         err = ceph_mdsc_do_request(mdsc,
263                                    (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
264                                    req);
265         if (err)
266                 goto out_err;
267 
268         err = ceph_handle_snapdir(req, dentry, err);
269         if (err == 0 && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
270                 err = ceph_handle_notrace_create(dir, dentry);
271 
272         if (d_unhashed(dentry)) {
273                 dn = ceph_finish_lookup(req, dentry, err);
274                 if (IS_ERR(dn))
275                         err = PTR_ERR(dn);
276         } else {
277                 /* we were given a hashed negative dentry */
278                 dn = NULL;
279         }
280         if (err)
281                 goto out_err;
282         if (dn || dentry->d_inode == NULL || S_ISLNK(dentry->d_inode->i_mode)) {
283                 /* make vfs retry on splice, ENOENT, or symlink */
284                 dout("atomic_open finish_no_open on dn %p\n", dn);
285                 err = finish_no_open(file, dn);
286         } else {
287                 dout("atomic_open finish_open on dn %p\n", dn);
288                 if (req->r_op == CEPH_MDS_OP_CREATE && req->r_reply_info.has_create_ino) {
289                         *opened |= FILE_CREATED;
290                 }
291                 err = finish_open(file, dentry, ceph_open, opened);
292         }
293 
294 out_err:
295         ceph_mdsc_put_request(req);
296         dout("atomic_open result=%d\n", err);
297         return err;
298 }
299 
300 int ceph_release(struct inode *inode, struct file *file)
301 {
302         struct ceph_inode_info *ci = ceph_inode(inode);
303         struct ceph_file_info *cf = file->private_data;
304 
305         dout("release inode %p file %p\n", inode, file);
306         ceph_put_fmode(ci, cf->fmode);
307         if (cf->last_readdir)
308                 ceph_mdsc_put_request(cf->last_readdir);
309         kfree(cf->last_name);
310         kfree(cf->dir_info);
311         dput(cf->dentry);
312         kmem_cache_free(ceph_file_cachep, cf);
313 
314         /* wake up anyone waiting for caps on this inode */
315         wake_up_all(&ci->i_cap_wq);
316         return 0;
317 }
318 
319 /*
320  * Read a range of bytes striped over one or more objects.  Iterate over
321  * objects we stripe over.  (That's not atomic, but good enough for now.)
322  *
323  * If we get a short result from the OSD, check against i_size; we need to
324  * only return a short read to the caller if we hit EOF.
325  */
326 static int striped_read(struct inode *inode,
327                         u64 off, u64 len,
328                         struct page **pages, int num_pages,
329                         int *checkeof, bool o_direct,
330                         unsigned long buf_align)
331 {
332         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
333         struct ceph_inode_info *ci = ceph_inode(inode);
334         u64 pos, this_len, left;
335         int io_align, page_align;
336         int pages_left;
337         int read;
338         struct page **page_pos;
339         int ret;
340         bool hit_stripe, was_short;
341 
342         /*
343          * we may need to do multiple reads.  not atomic, unfortunately.
344          */
345         pos = off;
346         left = len;
347         page_pos = pages;
348         pages_left = num_pages;
349         read = 0;
350         io_align = off & ~PAGE_MASK;
351 
352 more:
353         if (o_direct)
354                 page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
355         else
356                 page_align = pos & ~PAGE_MASK;
357         this_len = left;
358         ret = ceph_osdc_readpages(&fsc->client->osdc, ceph_vino(inode),
359                                   &ci->i_layout, pos, &this_len,
360                                   ci->i_truncate_seq,
361                                   ci->i_truncate_size,
362                                   page_pos, pages_left, page_align);
363         if (ret == -ENOENT)
364                 ret = 0;
365         hit_stripe = this_len < left;
366         was_short = ret >= 0 && ret < this_len;
367         dout("striped_read %llu~%llu (read %u) got %d%s%s\n", pos, left, read,
368              ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");
369 
370         if (ret >= 0) {
371                 int didpages;
372                 if (was_short && (pos + ret < inode->i_size)) {
373                         u64 tmp = min(this_len - ret,
374                                         inode->i_size - pos - ret);
375                         dout(" zero gap %llu to %llu\n",
376                                 pos + ret, pos + ret + tmp);
377                         ceph_zero_page_vector_range(page_align + read + ret,
378                                                         tmp, pages);
379                         ret += tmp;
380                 }
381 
382                 didpages = (page_align + ret) >> PAGE_CACHE_SHIFT;
383                 pos += ret;
384                 read = pos - off;
385                 left -= ret;
386                 page_pos += didpages;
387                 pages_left -= didpages;
388 
389                 /* hit stripe and need continue*/
390                 if (left && hit_stripe && pos < inode->i_size)
391                         goto more;
392         }
393 
394         if (read > 0) {
395                 ret = read;
396                 /* did we bounce off eof? */
397                 if (pos + left > inode->i_size)
398                         *checkeof = 1;
399         }
400 
401         dout("striped_read returns %d\n", ret);
402         return ret;
403 }
404 
405 /*
406  * Completely synchronous read and write methods.  Direct from __user
407  * buffer to osd, or directly to user pages (if O_DIRECT).
408  *
409  * If the read spans object boundary, just do multiple reads.
410  */
411 static ssize_t ceph_sync_read(struct file *file, char __user *data,
412                               unsigned len, loff_t *poff, int *checkeof)
413 {
414         struct inode *inode = file_inode(file);
415         struct page **pages;
416         u64 off = *poff;
417         int num_pages, ret;
418 
419         dout("sync_read on file %p %llu~%u %s\n", file, off, len,
420              (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
421 
422         if (file->f_flags & O_DIRECT) {
423                 num_pages = calc_pages_for((unsigned long)data, len);
424                 pages = ceph_get_direct_page_vector(data, num_pages, true);
425         } else {
426                 num_pages = calc_pages_for(off, len);
427                 pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
428         }
429         if (IS_ERR(pages))
430                 return PTR_ERR(pages);
431 
432         /*
433          * flush any page cache pages in this range.  this
434          * will make concurrent normal and sync io slow,
435          * but it will at least behave sensibly when they are
436          * in sequence.
437          */
438         ret = filemap_write_and_wait(inode->i_mapping);
439         if (ret < 0)
440                 goto done;
441 
442         ret = striped_read(inode, off, len, pages, num_pages, checkeof,
443                            file->f_flags & O_DIRECT,
444                            (unsigned long)data & ~PAGE_MASK);
445 
446         if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
447                 ret = ceph_copy_page_vector_to_user(pages, data, off, ret);
448         if (ret >= 0)
449                 *poff = off + ret;
450 
451 done:
452         if (file->f_flags & O_DIRECT)
453                 ceph_put_page_vector(pages, num_pages, true);
454         else
455                 ceph_release_page_vector(pages, num_pages);
456         dout("sync_read result %d\n", ret);
457         return ret;
458 }
459 
460 /*
461  * Write commit request unsafe callback, called to tell us when a
462  * request is unsafe (that is, in flight--has been handed to the
463  * messenger to send to its target osd).  It is called again when
464  * we've received a response message indicating the request is
465  * "safe" (its CEPH_OSD_FLAG_ONDISK flag is set), or when a request
466  * is completed early (and unsuccessfully) due to a timeout or
467  * interrupt.
468  *
469  * This is used if we requested both an ACK and ONDISK commit reply
470  * from the OSD.
471  */
472 static void ceph_sync_write_unsafe(struct ceph_osd_request *req, bool unsafe)
473 {
474         struct ceph_inode_info *ci = ceph_inode(req->r_inode);
475 
476         dout("%s %p tid %llu %ssafe\n", __func__, req, req->r_tid,
477                 unsafe ? "un" : "");
478         if (unsafe) {
479                 ceph_get_cap_refs(ci, CEPH_CAP_FILE_WR);
480                 spin_lock(&ci->i_unsafe_lock);
481                 list_add_tail(&req->r_unsafe_item,
482                               &ci->i_unsafe_writes);
483                 spin_unlock(&ci->i_unsafe_lock);
484         } else {
485                 spin_lock(&ci->i_unsafe_lock);
486                 list_del_init(&req->r_unsafe_item);
487                 spin_unlock(&ci->i_unsafe_lock);
488                 ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
489         }
490 }
491 
492 /*
493  * Synchronous write, straight from __user pointer or user pages (if
494  * O_DIRECT).
495  *
496  * If write spans object boundary, just do multiple writes.  (For a
497  * correct atomic write, we should e.g. take write locks on all
498  * objects, rollback on failure, etc.)
499  */
500 static ssize_t ceph_sync_write(struct file *file, const char __user *data,
501                                size_t left, loff_t pos, loff_t *ppos)
502 {
503         struct inode *inode = file_inode(file);
504         struct ceph_inode_info *ci = ceph_inode(inode);
505         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
506         struct ceph_snap_context *snapc;
507         struct ceph_vino vino;
508         struct ceph_osd_request *req;
509         int num_ops = 1;
510         struct page **pages;
511         int num_pages;
512         u64 len;
513         int written = 0;
514         int flags;
515         int check_caps = 0;
516         int page_align, io_align;
517         unsigned long buf_align;
518         int ret;
519         struct timespec mtime = CURRENT_TIME;
520         bool own_pages = false;
521 
522         if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
523                 return -EROFS;
524 
525         dout("sync_write on file %p %lld~%u %s\n", file, pos,
526              (unsigned)left, (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
527 
528         ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + left);
529         if (ret < 0)
530                 return ret;
531 
532         ret = invalidate_inode_pages2_range(inode->i_mapping,
533                                             pos >> PAGE_CACHE_SHIFT,
534                                             (pos + left) >> PAGE_CACHE_SHIFT);
535         if (ret < 0)
536                 dout("invalidate_inode_pages2_range returned %d\n", ret);
537 
538         flags = CEPH_OSD_FLAG_ORDERSNAP |
539                 CEPH_OSD_FLAG_ONDISK |
540                 CEPH_OSD_FLAG_WRITE;
541         if ((file->f_flags & (O_SYNC|O_DIRECT)) == 0)
542                 flags |= CEPH_OSD_FLAG_ACK;
543         else
544                 num_ops++;      /* Also include a 'startsync' command. */
545 
546         /*
547          * we may need to do multiple writes here if we span an object
548          * boundary.  this isn't atomic, unfortunately.  :(
549          */
550 more:
551         io_align = pos & ~PAGE_MASK;
552         buf_align = (unsigned long)data & ~PAGE_MASK;
553         len = left;
554 
555         snapc = ci->i_snap_realm->cached_context;
556         vino = ceph_vino(inode);
557         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
558                                     vino, pos, &len, num_ops,
559                                     CEPH_OSD_OP_WRITE, flags, snapc,
560                                     ci->i_truncate_seq, ci->i_truncate_size,
561                                     false);
562         if (IS_ERR(req))
563                 return PTR_ERR(req);
564 
565         /* write from beginning of first page, regardless of io alignment */
566         page_align = file->f_flags & O_DIRECT ? buf_align : io_align;
567         num_pages = calc_pages_for(page_align, len);
568         if (file->f_flags & O_DIRECT) {
569                 pages = ceph_get_direct_page_vector(data, num_pages, false);
570                 if (IS_ERR(pages)) {
571                         ret = PTR_ERR(pages);
572                         goto out;
573                 }
574 
575                 /*
576                  * throw out any page cache pages in this range. this
577                  * may block.
578                  */
579                 truncate_inode_pages_range(inode->i_mapping, pos,
580                                            (pos+len) | (PAGE_CACHE_SIZE-1));
581         } else {
582                 pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
583                 if (IS_ERR(pages)) {
584                         ret = PTR_ERR(pages);
585                         goto out;
586                 }
587                 ret = ceph_copy_user_to_page_vector(pages, data, pos, len);
588                 if (ret < 0) {
589                         ceph_release_page_vector(pages, num_pages);
590                         goto out;
591                 }
592 
593                 if ((file->f_flags & O_SYNC) == 0) {
594                         /* get a second commit callback */
595                         req->r_unsafe_callback = ceph_sync_write_unsafe;
596                         req->r_inode = inode;
597                         own_pages = true;
598                 }
599         }
600         osd_req_op_extent_osd_data_pages(req, 0, pages, len, page_align,
601                                         false, own_pages);
602 
603         /* BUG_ON(vino.snap != CEPH_NOSNAP); */
604         ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
605 
606         ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
607         if (!ret)
608                 ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
609 
610         if (file->f_flags & O_DIRECT)
611                 ceph_put_page_vector(pages, num_pages, false);
612         else if (file->f_flags & O_SYNC)
613                 ceph_release_page_vector(pages, num_pages);
614 
615 out:
616         ceph_osdc_put_request(req);
617         if (ret == 0) {
618                 pos += len;
619                 written += len;
620                 left -= len;
621                 data += len;
622                 if (left)
623                         goto more;
624 
625                 ret = written;
626                 *ppos = pos;
627                 if (pos > i_size_read(inode))
628                         check_caps = ceph_inode_set_size(inode, pos);
629                 if (check_caps)
630                         ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY,
631                                         NULL);
632         } else if (ret != -EOLDSNAPC && written > 0) {
633                 ret = written;
634         }
635         return ret;
636 }
637 
638 /*
639  * Wrap generic_file_aio_read with checks for cap bits on the inode.
640  * Atomically grab references, so that those bits are not released
641  * back to the MDS mid-read.
642  *
643  * Hmm, the sync read case isn't actually async... should it be?
644  */
645 static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
646                              unsigned long nr_segs, loff_t pos)
647 {
648         struct file *filp = iocb->ki_filp;
649         struct ceph_file_info *fi = filp->private_data;
650         loff_t *ppos = &iocb->ki_pos;
651         size_t len = iov->iov_len;
652         struct inode *inode = file_inode(filp);
653         struct ceph_inode_info *ci = ceph_inode(inode);
654         void __user *base = iov->iov_base;
655         ssize_t ret;
656         int want, got = 0;
657         int checkeof = 0, read = 0;
658 
659         dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
660              inode, ceph_vinop(inode), pos, (unsigned)len, inode);
661 again:
662         if (fi->fmode & CEPH_FILE_MODE_LAZY)
663                 want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
664         else
665                 want = CEPH_CAP_FILE_CACHE;
666         ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
667         if (ret < 0)
668                 goto out;
669         dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
670              inode, ceph_vinop(inode), pos, (unsigned)len,
671              ceph_cap_string(got));
672 
673         if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
674             (iocb->ki_filp->f_flags & O_DIRECT) ||
675             (fi->flags & CEPH_F_SYNC))
676                 /* hmm, this isn't really async... */
677                 ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
678         else
679                 ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
680 
681 out:
682         dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
683              inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
684         ceph_put_cap_refs(ci, got);
685 
686         if (checkeof && ret >= 0) {
687                 int statret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
688 
689                 /* hit EOF or hole? */
690                 if (statret == 0 && *ppos < inode->i_size) {
691                         dout("aio_read sync_read hit hole, ppos %lld < size %lld, reading more\n", *ppos, inode->i_size);
692                         read += ret;
693                         base += ret;
694                         len -= ret;
695                         checkeof = 0;
696                         goto again;
697                 }
698         }
699         if (ret >= 0)
700                 ret += read;
701 
702         return ret;
703 }
704 
705 /*
706  * Take cap references to avoid releasing caps to MDS mid-write.
707  *
708  * If we are synchronous, and write with an old snap context, the OSD
709  * may return EOLDSNAPC.  In that case, retry the write.. _after_
710  * dropping our cap refs and allowing the pending snap to logically
711  * complete _before_ this write occurs.
712  *
713  * If we are near ENOSPC, write synchronously.
714  */
715 static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
716                        unsigned long nr_segs, loff_t pos)
717 {
718         struct file *file = iocb->ki_filp;
719         struct ceph_file_info *fi = file->private_data;
720         struct inode *inode = file_inode(file);
721         struct ceph_inode_info *ci = ceph_inode(inode);
722         struct ceph_osd_client *osdc =
723                 &ceph_sb_to_client(inode->i_sb)->client->osdc;
724         ssize_t count, written = 0;
725         int err, want, got;
726 
727         if (ceph_snap(inode) != CEPH_NOSNAP)
728                 return -EROFS;
729 
730         mutex_lock(&inode->i_mutex);
731 
732         err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
733         if (err)
734                 goto out;
735 
736         /* We can write back this queue in page reclaim */
737         current->backing_dev_info = file->f_mapping->backing_dev_info;
738 
739         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
740         if (err)
741                 goto out;
742 
743         if (count == 0)
744                 goto out;
745 
746         err = file_remove_suid(file);
747         if (err)
748                 goto out;
749 
750         err = file_update_time(file);
751         if (err)
752                 goto out;
753 
754 retry_snap:
755         if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL)) {
756                 err = -ENOSPC;
757                 goto out;
758         }
759 
760         dout("aio_write %p %llx.%llx %llu~%zd getting caps. i_size %llu\n",
761              inode, ceph_vinop(inode), pos, count, inode->i_size);
762         if (fi->fmode & CEPH_FILE_MODE_LAZY)
763                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
764         else
765                 want = CEPH_CAP_FILE_BUFFER;
766         got = 0;
767         err = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, pos + count);
768         if (err < 0)
769                 goto out;
770 
771         dout("aio_write %p %llx.%llx %llu~%zd got cap refs on %s\n",
772              inode, ceph_vinop(inode), pos, count, ceph_cap_string(got));
773 
774         if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
775             (iocb->ki_filp->f_flags & O_DIRECT) ||
776             (fi->flags & CEPH_F_SYNC)) {
777                 mutex_unlock(&inode->i_mutex);
778                 written = ceph_sync_write(file, iov->iov_base, count,
779                                           pos, &iocb->ki_pos);
780                 if (written == -EOLDSNAPC) {
781                         dout("aio_write %p %llx.%llx %llu~%u"
782                                 "got EOLDSNAPC, retrying\n",
783                                 inode, ceph_vinop(inode),
784                                 pos, (unsigned)iov->iov_len);
785                         mutex_lock(&inode->i_mutex);
786                         goto retry_snap;
787                 }
788         } else {
789                 /*
790                  * No need to acquire the i_truncate_mutex. Because
791                  * the MDS revokes Fwb caps before sending truncate
792                  * message to us. We can't get Fwb cap while there
793                  * are pending vmtruncate. So write and vmtruncate
794                  * can not run at the same time
795                  */
796                 written = generic_file_buffered_write(iocb, iov, nr_segs,
797                                                       pos, &iocb->ki_pos,
798                                                       count, 0);
799                 mutex_unlock(&inode->i_mutex);
800         }
801 
802         if (written >= 0) {
803                 int dirty;
804                 spin_lock(&ci->i_ceph_lock);
805                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
806                 spin_unlock(&ci->i_ceph_lock);
807                 if (dirty)
808                         __mark_inode_dirty(inode, dirty);
809         }
810 
811         dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
812              inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
813              ceph_cap_string(got));
814         ceph_put_cap_refs(ci, got);
815 
816         if (written >= 0 &&
817             ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host) ||
818              ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
819                 err = vfs_fsync_range(file, pos, pos + written - 1, 1);
820                 if (err < 0)
821                         written = err;
822         }
823 
824         goto out_unlocked;
825 
826 out:
827         mutex_unlock(&inode->i_mutex);
828 out_unlocked:
829         current->backing_dev_info = NULL;
830         return written ? written : err;
831 }
832 
833 /*
834  * llseek.  be sure to verify file size on SEEK_END.
835  */
836 static loff_t ceph_llseek(struct file *file, loff_t offset, int whence)
837 {
838         struct inode *inode = file->f_mapping->host;
839         int ret;
840 
841         mutex_lock(&inode->i_mutex);
842 
843         if (whence == SEEK_END || whence == SEEK_DATA || whence == SEEK_HOLE) {
844                 ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
845                 if (ret < 0) {
846                         offset = ret;
847                         goto out;
848                 }
849         }
850 
851         switch (whence) {
852         case SEEK_END:
853                 offset += inode->i_size;
854                 break;
855         case SEEK_CUR:
856                 /*
857                  * Here we special-case the lseek(fd, 0, SEEK_CUR)
858                  * position-querying operation.  Avoid rewriting the "same"
859                  * f_pos value back to the file because a concurrent read(),
860                  * write() or lseek() might have altered it
861                  */
862                 if (offset == 0) {
863                         offset = file->f_pos;
864                         goto out;
865                 }
866                 offset += file->f_pos;
867                 break;
868         case SEEK_DATA:
869                 if (offset >= inode->i_size) {
870                         ret = -ENXIO;
871                         goto out;
872                 }
873                 break;
874         case SEEK_HOLE:
875                 if (offset >= inode->i_size) {
876                         ret = -ENXIO;
877                         goto out;
878                 }
879                 offset = inode->i_size;
880                 break;
881         }
882 
883         offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
884 
885 out:
886         mutex_unlock(&inode->i_mutex);
887         return offset;
888 }
889 
890 static inline void ceph_zero_partial_page(
891         struct inode *inode, loff_t offset, unsigned size)
892 {
893         struct page *page;
894         pgoff_t index = offset >> PAGE_CACHE_SHIFT;
895 
896         page = find_lock_page(inode->i_mapping, index);
897         if (page) {
898                 wait_on_page_writeback(page);
899                 zero_user(page, offset & (PAGE_CACHE_SIZE - 1), size);
900                 unlock_page(page);
901                 page_cache_release(page);
902         }
903 }
904 
905 static void ceph_zero_pagecache_range(struct inode *inode, loff_t offset,
906                                       loff_t length)
907 {
908         loff_t nearly = round_up(offset, PAGE_CACHE_SIZE);
909         if (offset < nearly) {
910                 loff_t size = nearly - offset;
911                 if (length < size)
912                         size = length;
913                 ceph_zero_partial_page(inode, offset, size);
914                 offset += size;
915                 length -= size;
916         }
917         if (length >= PAGE_CACHE_SIZE) {
918                 loff_t size = round_down(length, PAGE_CACHE_SIZE);
919                 truncate_pagecache_range(inode, offset, offset + size - 1);
920                 offset += size;
921                 length -= size;
922         }
923         if (length)
924                 ceph_zero_partial_page(inode, offset, length);
925 }
926 
927 static int ceph_zero_partial_object(struct inode *inode,
928                                     loff_t offset, loff_t *length)
929 {
930         struct ceph_inode_info *ci = ceph_inode(inode);
931         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
932         struct ceph_osd_request *req;
933         int ret = 0;
934         loff_t zero = 0;
935         int op;
936 
937         if (!length) {
938                 op = offset ? CEPH_OSD_OP_DELETE : CEPH_OSD_OP_TRUNCATE;
939                 length = &zero;
940         } else {
941                 op = CEPH_OSD_OP_ZERO;
942         }
943 
944         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
945                                         ceph_vino(inode),
946                                         offset, length,
947                                         1, op,
948                                         CEPH_OSD_FLAG_WRITE |
949                                         CEPH_OSD_FLAG_ONDISK,
950                                         NULL, 0, 0, false);
951         if (IS_ERR(req)) {
952                 ret = PTR_ERR(req);
953                 goto out;
954         }
955 
956         ceph_osdc_build_request(req, offset, NULL, ceph_vino(inode).snap,
957                                 &inode->i_mtime);
958 
959         ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
960         if (!ret) {
961                 ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
962                 if (ret == -ENOENT)
963                         ret = 0;
964         }
965         ceph_osdc_put_request(req);
966 
967 out:
968         return ret;
969 }
970 
971 static int ceph_zero_objects(struct inode *inode, loff_t offset, loff_t length)
972 {
973         int ret = 0;
974         struct ceph_inode_info *ci = ceph_inode(inode);
975         s32 stripe_unit = ceph_file_layout_su(ci->i_layout);
976         s32 stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
977         s32 object_size = ceph_file_layout_object_size(ci->i_layout);
978         u64 object_set_size = object_size * stripe_count;
979         u64 nearly, t;
980 
981         /* round offset up to next period boundary */
982         nearly = offset + object_set_size - 1;
983         t = nearly;
984         nearly -= do_div(t, object_set_size);
985 
986         while (length && offset < nearly) {
987                 loff_t size = length;
988                 ret = ceph_zero_partial_object(inode, offset, &size);
989                 if (ret < 0)
990                         return ret;
991                 offset += size;
992                 length -= size;
993         }
994         while (length >= object_set_size) {
995                 int i;
996                 loff_t pos = offset;
997                 for (i = 0; i < stripe_count; ++i) {
998                         ret = ceph_zero_partial_object(inode, pos, NULL);
999                         if (ret < 0)
1000                                 return ret;
1001                         pos += stripe_unit;
1002                 }
1003                 offset += object_set_size;
1004                 length -= object_set_size;
1005         }
1006         while (length) {
1007                 loff_t size = length;
1008                 ret = ceph_zero_partial_object(inode, offset, &size);
1009                 if (ret < 0)
1010                         return ret;
1011                 offset += size;
1012                 length -= size;
1013         }
1014         return ret;
1015 }
1016 
1017 static long ceph_fallocate(struct file *file, int mode,
1018                                 loff_t offset, loff_t length)
1019 {
1020         struct ceph_file_info *fi = file->private_data;
1021         struct inode *inode = file->f_dentry->d_inode;
1022         struct ceph_inode_info *ci = ceph_inode(inode);
1023         struct ceph_osd_client *osdc =
1024                 &ceph_inode_to_client(inode)->client->osdc;
1025         int want, got = 0;
1026         int dirty;
1027         int ret = 0;
1028         loff_t endoff = 0;
1029         loff_t size;
1030 
1031         if (!S_ISREG(inode->i_mode))
1032                 return -EOPNOTSUPP;
1033 
1034         if (IS_SWAPFILE(inode))
1035                 return -ETXTBSY;
1036 
1037         mutex_lock(&inode->i_mutex);
1038 
1039         if (ceph_snap(inode) != CEPH_NOSNAP) {
1040                 ret = -EROFS;
1041                 goto unlock;
1042         }
1043 
1044         if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL) &&
1045                 !(mode & FALLOC_FL_PUNCH_HOLE)) {
1046                 ret = -ENOSPC;
1047                 goto unlock;
1048         }
1049 
1050         size = i_size_read(inode);
1051         if (!(mode & FALLOC_FL_KEEP_SIZE))
1052                 endoff = offset + length;
1053 
1054         if (fi->fmode & CEPH_FILE_MODE_LAZY)
1055                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
1056         else
1057                 want = CEPH_CAP_FILE_BUFFER;
1058 
1059         ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, endoff);
1060         if (ret < 0)
1061                 goto unlock;
1062 
1063         if (mode & FALLOC_FL_PUNCH_HOLE) {
1064                 if (offset < size)
1065                         ceph_zero_pagecache_range(inode, offset, length);
1066                 ret = ceph_zero_objects(inode, offset, length);
1067         } else if (endoff > size) {
1068                 truncate_pagecache_range(inode, size, -1);
1069                 if (ceph_inode_set_size(inode, endoff))
1070                         ceph_check_caps(ceph_inode(inode),
1071                                 CHECK_CAPS_AUTHONLY, NULL);
1072         }
1073 
1074         if (!ret) {
1075                 spin_lock(&ci->i_ceph_lock);
1076                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
1077                 spin_unlock(&ci->i_ceph_lock);
1078                 if (dirty)
1079                         __mark_inode_dirty(inode, dirty);
1080         }
1081 
1082         ceph_put_cap_refs(ci, got);
1083 unlock:
1084         mutex_unlock(&inode->i_mutex);
1085         return ret;
1086 }
1087 
1088 const struct file_operations ceph_file_fops = {
1089         .open = ceph_open,
1090         .release = ceph_release,
1091         .llseek = ceph_llseek,
1092         .read = do_sync_read,
1093         .write = do_sync_write,
1094         .aio_read = ceph_aio_read,
1095         .aio_write = ceph_aio_write,
1096         .mmap = ceph_mmap,
1097         .fsync = ceph_fsync,
1098         .lock = ceph_lock,
1099         .flock = ceph_flock,
1100         .splice_read = generic_file_splice_read,
1101         .splice_write = generic_file_splice_write,
1102         .unlocked_ioctl = ceph_ioctl,
1103         .compat_ioctl   = ceph_ioctl,
1104         .fallocate      = ceph_fallocate,
1105 };
1106 
1107 

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