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TOMOYO Linux Cross Reference
Linux/fs/ceph/file.c

Version: ~ [ linux-5.4-rc7 ] ~ [ linux-5.3.11 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.84 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.154 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.201 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.201 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.77 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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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/falloc.h>
 11 
 12 #include "super.h"
 13 #include "mds_client.h"
 14 #include "cache.h"
 15 
 16 /*
 17  * Ceph file operations
 18  *
 19  * Implement basic open/close functionality, and implement
 20  * read/write.
 21  *
 22  * We implement three modes of file I/O:
 23  *  - buffered uses the generic_file_aio_{read,write} helpers
 24  *
 25  *  - synchronous is used when there is multi-client read/write
 26  *    sharing, avoids the page cache, and synchronously waits for an
 27  *    ack from the OSD.
 28  *
 29  *  - direct io takes the variant of the sync path that references
 30  *    user pages directly.
 31  *
 32  * fsync() flushes and waits on dirty pages, but just queues metadata
 33  * for writeback: since the MDS can recover size and mtime there is no
 34  * need to wait for MDS acknowledgement.
 35  */
 36 
 37 /*
 38  * Calculate the length sum of direct io vectors that can
 39  * be combined into one page vector.
 40  */
 41 static size_t dio_get_pagev_size(const struct iov_iter *it)
 42 {
 43     const struct iovec *iov = it->iov;
 44     const struct iovec *iovend = iov + it->nr_segs;
 45     size_t size;
 46 
 47     size = iov->iov_len - it->iov_offset;
 48     /*
 49      * An iov can be page vectored when both the current tail
 50      * and the next base are page aligned.
 51      */
 52     while (PAGE_ALIGNED((iov->iov_base + iov->iov_len)) &&
 53            (++iov < iovend && PAGE_ALIGNED((iov->iov_base)))) {
 54         size += iov->iov_len;
 55     }
 56     dout("dio_get_pagevlen len = %zu\n", size);
 57     return size;
 58 }
 59 
 60 /*
 61  * Allocate a page vector based on (@it, @nbytes).
 62  * The return value is the tuple describing a page vector,
 63  * that is (@pages, @page_align, @num_pages).
 64  */
 65 static struct page **
 66 dio_get_pages_alloc(const struct iov_iter *it, size_t nbytes,
 67                     size_t *page_align, int *num_pages)
 68 {
 69         struct iov_iter tmp_it = *it;
 70         size_t align;
 71         struct page **pages;
 72         int ret = 0, idx, npages;
 73 
 74         align = (unsigned long)(it->iov->iov_base + it->iov_offset) &
 75                 (PAGE_SIZE - 1);
 76         npages = calc_pages_for(align, nbytes);
 77         pages = kmalloc(sizeof(*pages) * npages, GFP_KERNEL);
 78         if (!pages) {
 79                 pages = vmalloc(sizeof(*pages) * npages);
 80                 if (!pages)
 81                         return ERR_PTR(-ENOMEM);
 82         }
 83 
 84         for (idx = 0; idx < npages; ) {
 85                 size_t start;
 86                 ret = iov_iter_get_pages(&tmp_it, pages + idx, nbytes,
 87                                          npages - idx, &start);
 88                 if (ret < 0)
 89                         goto fail;
 90 
 91                 iov_iter_advance(&tmp_it, ret);
 92                 nbytes -= ret;
 93                 idx += (ret + start + PAGE_SIZE - 1) / PAGE_SIZE;
 94         }
 95 
 96         BUG_ON(nbytes != 0);
 97         *num_pages = npages;
 98         *page_align = align;
 99         dout("dio_get_pages_alloc: got %d pages align %zu\n", npages, align);
100         return pages;
101 fail:
102         ceph_put_page_vector(pages, idx, false);
103         return ERR_PTR(ret);
104 }
105 
106 /*
107  * Prepare an open request.  Preallocate ceph_cap to avoid an
108  * inopportune ENOMEM later.
109  */
110 static struct ceph_mds_request *
111 prepare_open_request(struct super_block *sb, int flags, int create_mode)
112 {
113         struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
114         struct ceph_mds_client *mdsc = fsc->mdsc;
115         struct ceph_mds_request *req;
116         int want_auth = USE_ANY_MDS;
117         int op = (flags & O_CREAT) ? CEPH_MDS_OP_CREATE : CEPH_MDS_OP_OPEN;
118 
119         if (flags & (O_WRONLY|O_RDWR|O_CREAT|O_TRUNC))
120                 want_auth = USE_AUTH_MDS;
121 
122         req = ceph_mdsc_create_request(mdsc, op, want_auth);
123         if (IS_ERR(req))
124                 goto out;
125         req->r_fmode = ceph_flags_to_mode(flags);
126         req->r_args.open.flags = cpu_to_le32(flags);
127         req->r_args.open.mode = cpu_to_le32(create_mode);
128 out:
129         return req;
130 }
131 
132 /*
133  * initialize private struct file data.
134  * if we fail, clean up by dropping fmode reference on the ceph_inode
135  */
136 static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
137 {
138         struct ceph_file_info *cf;
139         int ret = 0;
140         struct ceph_inode_info *ci = ceph_inode(inode);
141         struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
142         struct ceph_mds_client *mdsc = fsc->mdsc;
143 
144         switch (inode->i_mode & S_IFMT) {
145         case S_IFREG:
146                 /* First file open request creates the cookie, we want to keep
147                  * this cookie around for the filetime of the inode as not to
148                  * have to worry about fscache register / revoke / operation
149                  * races.
150                  *
151                  * Also, if we know the operation is going to invalidate data
152                  * (non readonly) just nuke the cache right away.
153                  */
154                 ceph_fscache_register_inode_cookie(mdsc->fsc, ci);
155                 if ((fmode & CEPH_FILE_MODE_WR))
156                         ceph_fscache_invalidate(inode);
157         case S_IFDIR:
158                 dout("init_file %p %p 0%o (regular)\n", inode, file,
159                      inode->i_mode);
160                 cf = kmem_cache_zalloc(ceph_file_cachep, GFP_KERNEL);
161                 if (cf == NULL) {
162                         ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
163                         return -ENOMEM;
164                 }
165                 cf->fmode = fmode;
166                 cf->next_offset = 2;
167                 cf->readdir_cache_idx = -1;
168                 file->private_data = cf;
169                 BUG_ON(inode->i_fop->release != ceph_release);
170                 break;
171 
172         case S_IFLNK:
173                 dout("init_file %p %p 0%o (symlink)\n", inode, file,
174                      inode->i_mode);
175                 ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
176                 break;
177 
178         default:
179                 dout("init_file %p %p 0%o (special)\n", inode, file,
180                      inode->i_mode);
181                 /*
182                  * we need to drop the open ref now, since we don't
183                  * have .release set to ceph_release.
184                  */
185                 ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
186                 BUG_ON(inode->i_fop->release == ceph_release);
187 
188                 /* call the proper open fop */
189                 ret = inode->i_fop->open(inode, file);
190         }
191         return ret;
192 }
193 
194 /*
195  * If we already have the requisite capabilities, we can satisfy
196  * the open request locally (no need to request new caps from the
197  * MDS).  We do, however, need to inform the MDS (asynchronously)
198  * if our wanted caps set expands.
199  */
200 int ceph_open(struct inode *inode, struct file *file)
201 {
202         struct ceph_inode_info *ci = ceph_inode(inode);
203         struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
204         struct ceph_mds_client *mdsc = fsc->mdsc;
205         struct ceph_mds_request *req;
206         struct ceph_file_info *cf = file->private_data;
207         int err;
208         int flags, fmode, wanted;
209 
210         if (cf) {
211                 dout("open file %p is already opened\n", file);
212                 return 0;
213         }
214 
215         /* filter out O_CREAT|O_EXCL; vfs did that already.  yuck. */
216         flags = file->f_flags & ~(O_CREAT|O_EXCL);
217         if (S_ISDIR(inode->i_mode))
218                 flags = O_DIRECTORY;  /* mds likes to know */
219 
220         dout("open inode %p ino %llx.%llx file %p flags %d (%d)\n", inode,
221              ceph_vinop(inode), file, flags, file->f_flags);
222         fmode = ceph_flags_to_mode(flags);
223         wanted = ceph_caps_for_mode(fmode);
224 
225         /* snapped files are read-only */
226         if (ceph_snap(inode) != CEPH_NOSNAP && (file->f_mode & FMODE_WRITE))
227                 return -EROFS;
228 
229         /* trivially open snapdir */
230         if (ceph_snap(inode) == CEPH_SNAPDIR) {
231                 spin_lock(&ci->i_ceph_lock);
232                 __ceph_get_fmode(ci, fmode);
233                 spin_unlock(&ci->i_ceph_lock);
234                 return ceph_init_file(inode, file, fmode);
235         }
236 
237         /*
238          * No need to block if we have caps on the auth MDS (for
239          * write) or any MDS (for read).  Update wanted set
240          * asynchronously.
241          */
242         spin_lock(&ci->i_ceph_lock);
243         if (__ceph_is_any_real_caps(ci) &&
244             (((fmode & CEPH_FILE_MODE_WR) == 0) || ci->i_auth_cap)) {
245                 int mds_wanted = __ceph_caps_mds_wanted(ci);
246                 int issued = __ceph_caps_issued(ci, NULL);
247 
248                 dout("open %p fmode %d want %s issued %s using existing\n",
249                      inode, fmode, ceph_cap_string(wanted),
250                      ceph_cap_string(issued));
251                 __ceph_get_fmode(ci, fmode);
252                 spin_unlock(&ci->i_ceph_lock);
253 
254                 /* adjust wanted? */
255                 if ((issued & wanted) != wanted &&
256                     (mds_wanted & wanted) != wanted &&
257                     ceph_snap(inode) != CEPH_SNAPDIR)
258                         ceph_check_caps(ci, 0, NULL);
259 
260                 return ceph_init_file(inode, file, fmode);
261         } else if (ceph_snap(inode) != CEPH_NOSNAP &&
262                    (ci->i_snap_caps & wanted) == wanted) {
263                 __ceph_get_fmode(ci, fmode);
264                 spin_unlock(&ci->i_ceph_lock);
265                 return ceph_init_file(inode, file, fmode);
266         }
267 
268         spin_unlock(&ci->i_ceph_lock);
269 
270         dout("open fmode %d wants %s\n", fmode, ceph_cap_string(wanted));
271         req = prepare_open_request(inode->i_sb, flags, 0);
272         if (IS_ERR(req)) {
273                 err = PTR_ERR(req);
274                 goto out;
275         }
276         req->r_inode = inode;
277         ihold(inode);
278 
279         req->r_num_caps = 1;
280         err = ceph_mdsc_do_request(mdsc, NULL, req);
281         if (!err)
282                 err = ceph_init_file(inode, file, req->r_fmode);
283         ceph_mdsc_put_request(req);
284         dout("open result=%d on %llx.%llx\n", err, ceph_vinop(inode));
285 out:
286         return err;
287 }
288 
289 
290 /*
291  * Do a lookup + open with a single request.  If we get a non-existent
292  * file or symlink, return 1 so the VFS can retry.
293  */
294 int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
295                      struct file *file, unsigned flags, umode_t mode,
296                      int *opened)
297 {
298         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
299         struct ceph_mds_client *mdsc = fsc->mdsc;
300         struct ceph_mds_request *req;
301         struct dentry *dn;
302         struct ceph_acls_info acls = {};
303        int mask;
304         int err;
305 
306         dout("atomic_open %p dentry %p '%pd' %s flags %d mode 0%o\n",
307              dir, dentry, dentry,
308              d_unhashed(dentry) ? "unhashed" : "hashed", flags, mode);
309 
310         if (dentry->d_name.len > NAME_MAX)
311                 return -ENAMETOOLONG;
312 
313         err = ceph_init_dentry(dentry);
314         if (err < 0)
315                 return err;
316 
317         if (flags & O_CREAT) {
318                 err = ceph_pre_init_acls(dir, &mode, &acls);
319                 if (err < 0)
320                         return err;
321         }
322 
323         /* do the open */
324         req = prepare_open_request(dir->i_sb, flags, mode);
325         if (IS_ERR(req)) {
326                 err = PTR_ERR(req);
327                 goto out_acl;
328         }
329         req->r_dentry = dget(dentry);
330         req->r_num_caps = 2;
331         if (flags & O_CREAT) {
332                 req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
333                 req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
334                 if (acls.pagelist) {
335                         req->r_pagelist = acls.pagelist;
336                         acls.pagelist = NULL;
337                 }
338         }
339 
340        mask = CEPH_STAT_CAP_INODE | CEPH_CAP_AUTH_SHARED;
341        if (ceph_security_xattr_wanted(dir))
342                mask |= CEPH_CAP_XATTR_SHARED;
343        req->r_args.open.mask = cpu_to_le32(mask);
344 
345         req->r_locked_dir = dir;           /* caller holds dir->i_mutex */
346         err = ceph_mdsc_do_request(mdsc,
347                                    (flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
348                                    req);
349         err = ceph_handle_snapdir(req, dentry, err);
350         if (err)
351                 goto out_req;
352 
353         if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
354                 err = ceph_handle_notrace_create(dir, dentry);
355 
356         if (d_unhashed(dentry)) {
357                 dn = ceph_finish_lookup(req, dentry, err);
358                 if (IS_ERR(dn))
359                         err = PTR_ERR(dn);
360         } else {
361                 /* we were given a hashed negative dentry */
362                 dn = NULL;
363         }
364         if (err)
365                 goto out_req;
366         if (dn || d_really_is_negative(dentry) || d_is_symlink(dentry)) {
367                 /* make vfs retry on splice, ENOENT, or symlink */
368                 dout("atomic_open finish_no_open on dn %p\n", dn);
369                 err = finish_no_open(file, dn);
370         } else {
371                 dout("atomic_open finish_open on dn %p\n", dn);
372                 if (req->r_op == CEPH_MDS_OP_CREATE && req->r_reply_info.has_create_ino) {
373                         ceph_init_inode_acls(d_inode(dentry), &acls);
374                         *opened |= FILE_CREATED;
375                 }
376                 err = finish_open(file, dentry, ceph_open, opened);
377         }
378 out_req:
379         if (!req->r_err && req->r_target_inode)
380                 ceph_put_fmode(ceph_inode(req->r_target_inode), req->r_fmode);
381         ceph_mdsc_put_request(req);
382 out_acl:
383         ceph_release_acls_info(&acls);
384         dout("atomic_open result=%d\n", err);
385         return err;
386 }
387 
388 int ceph_release(struct inode *inode, struct file *file)
389 {
390         struct ceph_inode_info *ci = ceph_inode(inode);
391         struct ceph_file_info *cf = file->private_data;
392 
393         dout("release inode %p file %p\n", inode, file);
394         ceph_put_fmode(ci, cf->fmode);
395         if (cf->last_readdir)
396                 ceph_mdsc_put_request(cf->last_readdir);
397         kfree(cf->last_name);
398         kfree(cf->dir_info);
399         kmem_cache_free(ceph_file_cachep, cf);
400 
401         /* wake up anyone waiting for caps on this inode */
402         wake_up_all(&ci->i_cap_wq);
403         return 0;
404 }
405 
406 enum {
407         HAVE_RETRIED = 1,
408         CHECK_EOF =    2,
409         READ_INLINE =  3,
410 };
411 
412 /*
413  * Read a range of bytes striped over one or more objects.  Iterate over
414  * objects we stripe over.  (That's not atomic, but good enough for now.)
415  *
416  * If we get a short result from the OSD, check against i_size; we need to
417  * only return a short read to the caller if we hit EOF.
418  */
419 static int striped_read(struct inode *inode,
420                         u64 off, u64 len,
421                         struct page **pages, int num_pages,
422                         int *checkeof)
423 {
424         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
425         struct ceph_inode_info *ci = ceph_inode(inode);
426         u64 pos, this_len, left;
427         loff_t i_size;
428         int page_align, pages_left;
429         int read, ret;
430         struct page **page_pos;
431         bool hit_stripe, was_short;
432 
433         /*
434          * we may need to do multiple reads.  not atomic, unfortunately.
435          */
436         pos = off;
437         left = len;
438         page_pos = pages;
439         pages_left = num_pages;
440         read = 0;
441 
442 more:
443         page_align = pos & ~PAGE_MASK;
444         this_len = left;
445         ret = ceph_osdc_readpages(&fsc->client->osdc, ceph_vino(inode),
446                                   &ci->i_layout, pos, &this_len,
447                                   ci->i_truncate_seq,
448                                   ci->i_truncate_size,
449                                   page_pos, pages_left, page_align);
450         if (ret == -ENOENT)
451                 ret = 0;
452         hit_stripe = this_len < left;
453         was_short = ret >= 0 && ret < this_len;
454         dout("striped_read %llu~%llu (read %u) got %d%s%s\n", pos, left, read,
455              ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");
456 
457         i_size = i_size_read(inode);
458         if (ret >= 0) {
459                 int didpages;
460                 if (was_short && (pos + ret < i_size)) {
461                         int zlen = min(this_len - ret, i_size - pos - ret);
462                         int zoff = (off & ~PAGE_MASK) + read + ret;
463                         dout(" zero gap %llu to %llu\n",
464                                 pos + ret, pos + ret + zlen);
465                         ceph_zero_page_vector_range(zoff, zlen, pages);
466                         ret += zlen;
467                 }
468 
469                 didpages = (page_align + ret) >> PAGE_SHIFT;
470                 pos += ret;
471                 read = pos - off;
472                 left -= ret;
473                 page_pos += didpages;
474                 pages_left -= didpages;
475 
476                 /* hit stripe and need continue*/
477                 if (left && hit_stripe && pos < i_size)
478                         goto more;
479         }
480 
481         if (read > 0) {
482                 ret = read;
483                 /* did we bounce off eof? */
484                 if (pos + left > i_size)
485                         *checkeof = CHECK_EOF;
486         }
487 
488         dout("striped_read returns %d\n", ret);
489         return ret;
490 }
491 
492 /*
493  * Completely synchronous read and write methods.  Direct from __user
494  * buffer to osd, or directly to user pages (if O_DIRECT).
495  *
496  * If the read spans object boundary, just do multiple reads.
497  */
498 static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *i,
499                                 int *checkeof)
500 {
501         struct file *file = iocb->ki_filp;
502         struct inode *inode = file_inode(file);
503         struct page **pages;
504         u64 off = iocb->ki_pos;
505         int num_pages, ret;
506         size_t len = iov_iter_count(i);
507 
508         dout("sync_read on file %p %llu~%u %s\n", file, off,
509              (unsigned)len,
510              (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
511 
512         if (!len)
513                 return 0;
514         /*
515          * flush any page cache pages in this range.  this
516          * will make concurrent normal and sync io slow,
517          * but it will at least behave sensibly when they are
518          * in sequence.
519          */
520         ret = filemap_write_and_wait_range(inode->i_mapping, off,
521                                                 off + len);
522         if (ret < 0)
523                 return ret;
524 
525         num_pages = calc_pages_for(off, len);
526         pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
527         if (IS_ERR(pages))
528                 return PTR_ERR(pages);
529         ret = striped_read(inode, off, len, pages,
530                                 num_pages, checkeof);
531         if (ret > 0) {
532                 int l, k = 0;
533                 size_t left = ret;
534 
535                 while (left) {
536                         size_t page_off = off & ~PAGE_MASK;
537                         size_t copy = min_t(size_t, left,
538                                             PAGE_SIZE - page_off);
539                         l = copy_page_to_iter(pages[k++], page_off, copy, i);
540                         off += l;
541                         left -= l;
542                         if (l < copy)
543                                 break;
544                 }
545         }
546         ceph_release_page_vector(pages, num_pages);
547 
548         if (off > iocb->ki_pos) {
549                 ret = off - iocb->ki_pos;
550                 iocb->ki_pos = off;
551         }
552 
553         dout("sync_read result %d\n", ret);
554         return ret;
555 }
556 
557 struct ceph_aio_request {
558         struct kiocb *iocb;
559         size_t total_len;
560         int write;
561         int error;
562         struct list_head osd_reqs;
563         unsigned num_reqs;
564         atomic_t pending_reqs;
565         struct timespec mtime;
566         struct ceph_cap_flush *prealloc_cf;
567 };
568 
569 struct ceph_aio_work {
570         struct work_struct work;
571         struct ceph_osd_request *req;
572 };
573 
574 static void ceph_aio_retry_work(struct work_struct *work);
575 
576 static void ceph_aio_complete(struct inode *inode,
577                               struct ceph_aio_request *aio_req)
578 {
579         struct ceph_inode_info *ci = ceph_inode(inode);
580         int ret;
581 
582         if (!atomic_dec_and_test(&aio_req->pending_reqs))
583                 return;
584 
585         ret = aio_req->error;
586         if (!ret)
587                 ret = aio_req->total_len;
588 
589         dout("ceph_aio_complete %p rc %d\n", inode, ret);
590 
591         if (ret >= 0 && aio_req->write) {
592                 int dirty;
593 
594                 loff_t endoff = aio_req->iocb->ki_pos + aio_req->total_len;
595                 if (endoff > i_size_read(inode)) {
596                         if (ceph_inode_set_size(inode, endoff))
597                                 ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
598                 }
599 
600                 spin_lock(&ci->i_ceph_lock);
601                 ci->i_inline_version = CEPH_INLINE_NONE;
602                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR,
603                                                &aio_req->prealloc_cf);
604                 spin_unlock(&ci->i_ceph_lock);
605                 if (dirty)
606                         __mark_inode_dirty(inode, dirty);
607 
608         }
609 
610         ceph_put_cap_refs(ci, (aio_req->write ? CEPH_CAP_FILE_WR :
611                                                 CEPH_CAP_FILE_RD));
612 
613         aio_req->iocb->ki_complete(aio_req->iocb, ret, 0);
614 
615         ceph_free_cap_flush(aio_req->prealloc_cf);
616         kfree(aio_req);
617 }
618 
619 static void ceph_aio_complete_req(struct ceph_osd_request *req,
620                                   struct ceph_msg *msg)
621 {
622         int rc = req->r_result;
623         struct inode *inode = req->r_inode;
624         struct ceph_aio_request *aio_req = req->r_priv;
625         struct ceph_osd_data *osd_data = osd_req_op_extent_osd_data(req, 0);
626         int num_pages = calc_pages_for((u64)osd_data->alignment,
627                                        osd_data->length);
628 
629         dout("ceph_aio_complete_req %p rc %d bytes %llu\n",
630              inode, rc, osd_data->length);
631 
632         if (rc == -EOLDSNAPC) {
633                 struct ceph_aio_work *aio_work;
634                 BUG_ON(!aio_req->write);
635 
636                 aio_work = kmalloc(sizeof(*aio_work), GFP_NOFS);
637                 if (aio_work) {
638                         INIT_WORK(&aio_work->work, ceph_aio_retry_work);
639                         aio_work->req = req;
640                         queue_work(ceph_inode_to_client(inode)->wb_wq,
641                                    &aio_work->work);
642                         return;
643                 }
644                 rc = -ENOMEM;
645         } else if (!aio_req->write) {
646                 if (rc == -ENOENT)
647                         rc = 0;
648                 if (rc >= 0 && osd_data->length > rc) {
649                         int zoff = osd_data->alignment + rc;
650                         int zlen = osd_data->length - rc;
651                         /*
652                          * If read is satisfied by single OSD request,
653                          * it can pass EOF. Otherwise read is within
654                          * i_size.
655                          */
656                         if (aio_req->num_reqs == 1) {
657                                 loff_t i_size = i_size_read(inode);
658                                 loff_t endoff = aio_req->iocb->ki_pos + rc;
659                                 if (endoff < i_size)
660                                         zlen = min_t(size_t, zlen,
661                                                      i_size - endoff);
662                                 aio_req->total_len = rc + zlen;
663                         }
664 
665                         if (zlen > 0)
666                                 ceph_zero_page_vector_range(zoff, zlen,
667                                                             osd_data->pages);
668                 }
669         }
670 
671         ceph_put_page_vector(osd_data->pages, num_pages, false);
672         ceph_osdc_put_request(req);
673 
674         if (rc < 0)
675                 cmpxchg(&aio_req->error, 0, rc);
676 
677         ceph_aio_complete(inode, aio_req);
678         return;
679 }
680 
681 static void ceph_aio_retry_work(struct work_struct *work)
682 {
683         struct ceph_aio_work *aio_work =
684                 container_of(work, struct ceph_aio_work, work);
685         struct ceph_osd_request *orig_req = aio_work->req;
686         struct ceph_aio_request *aio_req = orig_req->r_priv;
687         struct inode *inode = orig_req->r_inode;
688         struct ceph_inode_info *ci = ceph_inode(inode);
689         struct ceph_snap_context *snapc;
690         struct ceph_osd_request *req;
691         int ret;
692 
693         spin_lock(&ci->i_ceph_lock);
694         if (__ceph_have_pending_cap_snap(ci)) {
695                 struct ceph_cap_snap *capsnap =
696                         list_last_entry(&ci->i_cap_snaps,
697                                         struct ceph_cap_snap,
698                                         ci_item);
699                 snapc = ceph_get_snap_context(capsnap->context);
700         } else {
701                 BUG_ON(!ci->i_head_snapc);
702                 snapc = ceph_get_snap_context(ci->i_head_snapc);
703         }
704         spin_unlock(&ci->i_ceph_lock);
705 
706         req = ceph_osdc_alloc_request(orig_req->r_osdc, snapc, 2,
707                         false, GFP_NOFS);
708         if (!req) {
709                 ret = -ENOMEM;
710                 req = orig_req;
711                 goto out;
712         }
713 
714         req->r_flags =  CEPH_OSD_FLAG_ORDERSNAP |
715                         CEPH_OSD_FLAG_ONDISK |
716                         CEPH_OSD_FLAG_WRITE;
717         req->r_base_oloc = orig_req->r_base_oloc;
718         req->r_base_oid = orig_req->r_base_oid;
719 
720         req->r_ops[0] = orig_req->r_ops[0];
721         osd_req_op_init(req, 1, CEPH_OSD_OP_STARTSYNC, 0);
722 
723         ceph_osdc_build_request(req, req->r_ops[0].extent.offset,
724                                 snapc, CEPH_NOSNAP, &aio_req->mtime);
725 
726         ceph_osdc_put_request(orig_req);
727 
728         req->r_callback = ceph_aio_complete_req;
729         req->r_inode = inode;
730         req->r_priv = aio_req;
731 
732         ret = ceph_osdc_start_request(req->r_osdc, req, false);
733 out:
734         if (ret < 0) {
735                 req->r_result = ret;
736                 ceph_aio_complete_req(req, NULL);
737         }
738 
739         ceph_put_snap_context(snapc);
740         kfree(aio_work);
741 }
742 
743 /*
744  * Write commit request unsafe callback, called to tell us when a
745  * request is unsafe (that is, in flight--has been handed to the
746  * messenger to send to its target osd).  It is called again when
747  * we've received a response message indicating the request is
748  * "safe" (its CEPH_OSD_FLAG_ONDISK flag is set), or when a request
749  * is completed early (and unsuccessfully) due to a timeout or
750  * interrupt.
751  *
752  * This is used if we requested both an ACK and ONDISK commit reply
753  * from the OSD.
754  */
755 static void ceph_sync_write_unsafe(struct ceph_osd_request *req, bool unsafe)
756 {
757         struct ceph_inode_info *ci = ceph_inode(req->r_inode);
758 
759         dout("%s %p tid %llu %ssafe\n", __func__, req, req->r_tid,
760                 unsafe ? "un" : "");
761         if (unsafe) {
762                 ceph_get_cap_refs(ci, CEPH_CAP_FILE_WR);
763                 spin_lock(&ci->i_unsafe_lock);
764                 list_add_tail(&req->r_unsafe_item,
765                               &ci->i_unsafe_writes);
766                 spin_unlock(&ci->i_unsafe_lock);
767         } else {
768                 spin_lock(&ci->i_unsafe_lock);
769                 list_del_init(&req->r_unsafe_item);
770                 spin_unlock(&ci->i_unsafe_lock);
771                 ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
772         }
773 }
774 
775 
776 static ssize_t
777 ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
778                        struct ceph_snap_context *snapc,
779                        struct ceph_cap_flush **pcf)
780 {
781         struct file *file = iocb->ki_filp;
782         struct inode *inode = file_inode(file);
783         struct ceph_inode_info *ci = ceph_inode(inode);
784         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
785         struct ceph_vino vino;
786         struct ceph_osd_request *req;
787         struct page **pages;
788         struct ceph_aio_request *aio_req = NULL;
789         int num_pages = 0;
790         int flags;
791         int ret;
792         struct timespec mtime = current_fs_time(inode->i_sb);
793         size_t count = iov_iter_count(iter);
794         loff_t pos = iocb->ki_pos;
795         bool write = iov_iter_rw(iter) == WRITE;
796 
797         if (write && ceph_snap(file_inode(file)) != CEPH_NOSNAP)
798                 return -EROFS;
799 
800         dout("sync_direct_read_write (%s) on file %p %lld~%u\n",
801              (write ? "write" : "read"), file, pos, (unsigned)count);
802 
803         ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + count);
804         if (ret < 0)
805                 return ret;
806 
807         if (write) {
808                 ret = invalidate_inode_pages2_range(inode->i_mapping,
809                                         pos >> PAGE_SHIFT,
810                                         (pos + count) >> PAGE_SHIFT);
811                 if (ret < 0)
812                         dout("invalidate_inode_pages2_range returned %d\n", ret);
813 
814                 flags = CEPH_OSD_FLAG_ORDERSNAP |
815                         CEPH_OSD_FLAG_ONDISK |
816                         CEPH_OSD_FLAG_WRITE;
817         } else {
818                 flags = CEPH_OSD_FLAG_READ;
819         }
820 
821         while (iov_iter_count(iter) > 0) {
822                 u64 size = dio_get_pagev_size(iter);
823                 size_t start = 0;
824                 ssize_t len;
825 
826                 vino = ceph_vino(inode);
827                 req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
828                                             vino, pos, &size, 0,
829                                             /*include a 'startsync' command*/
830                                             write ? 2 : 1,
831                                             write ? CEPH_OSD_OP_WRITE :
832                                                     CEPH_OSD_OP_READ,
833                                             flags, snapc,
834                                             ci->i_truncate_seq,
835                                             ci->i_truncate_size,
836                                             false);
837                 if (IS_ERR(req)) {
838                         ret = PTR_ERR(req);
839                         break;
840                 }
841 
842                 len = size;
843                 pages = dio_get_pages_alloc(iter, len, &start, &num_pages);
844                 if (IS_ERR(pages)) {
845                         ceph_osdc_put_request(req);
846                         ret = PTR_ERR(pages);
847                         break;
848                 }
849 
850                 /*
851                  * To simplify error handling, allow AIO when IO within i_size
852                  * or IO can be satisfied by single OSD request.
853                  */
854                 if (pos == iocb->ki_pos && !is_sync_kiocb(iocb) &&
855                     (len == count || pos + count <= i_size_read(inode))) {
856                         aio_req = kzalloc(sizeof(*aio_req), GFP_KERNEL);
857                         if (aio_req) {
858                                 aio_req->iocb = iocb;
859                                 aio_req->write = write;
860                                 INIT_LIST_HEAD(&aio_req->osd_reqs);
861                                 if (write) {
862                                         aio_req->mtime = mtime;
863                                         swap(aio_req->prealloc_cf, *pcf);
864                                 }
865                         }
866                         /* ignore error */
867                 }
868 
869                 if (write) {
870                         /*
871                          * throw out any page cache pages in this range. this
872                          * may block.
873                          */
874                         truncate_inode_pages_range(inode->i_mapping, pos,
875                                         (pos+len) | (PAGE_SIZE - 1));
876 
877                         osd_req_op_init(req, 1, CEPH_OSD_OP_STARTSYNC, 0);
878                 }
879 
880 
881                 osd_req_op_extent_osd_data_pages(req, 0, pages, len, start,
882                                                  false, false);
883 
884                 ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
885 
886                 if (aio_req) {
887                         aio_req->total_len += len;
888                         aio_req->num_reqs++;
889                         atomic_inc(&aio_req->pending_reqs);
890 
891                         req->r_callback = ceph_aio_complete_req;
892                         req->r_inode = inode;
893                         req->r_priv = aio_req;
894                         list_add_tail(&req->r_unsafe_item, &aio_req->osd_reqs);
895 
896                         pos += len;
897                         iov_iter_advance(iter, len);
898                         continue;
899                 }
900 
901                 ret = ceph_osdc_start_request(req->r_osdc, req, false);
902                 if (!ret)
903                         ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
904 
905                 size = i_size_read(inode);
906                 if (!write) {
907                         if (ret == -ENOENT)
908                                 ret = 0;
909                         if (ret >= 0 && ret < len && pos + ret < size) {
910                                 int zlen = min_t(size_t, len - ret,
911                                                  size - pos - ret);
912                                 ceph_zero_page_vector_range(start + ret, zlen,
913                                                             pages);
914                                 ret += zlen;
915                         }
916                         if (ret >= 0)
917                                 len = ret;
918                 }
919 
920                 ceph_put_page_vector(pages, num_pages, false);
921 
922                 ceph_osdc_put_request(req);
923                 if (ret < 0)
924                         break;
925 
926                 pos += len;
927                 iov_iter_advance(iter, len);
928 
929                 if (!write && pos >= size)
930                         break;
931 
932                 if (write && pos > size) {
933                         if (ceph_inode_set_size(inode, pos))
934                                 ceph_check_caps(ceph_inode(inode),
935                                                 CHECK_CAPS_AUTHONLY,
936                                                 NULL);
937                 }
938         }
939 
940         if (aio_req) {
941                 if (aio_req->num_reqs == 0) {
942                         kfree(aio_req);
943                         return ret;
944                 }
945 
946                 ceph_get_cap_refs(ci, write ? CEPH_CAP_FILE_WR :
947                                               CEPH_CAP_FILE_RD);
948 
949                 while (!list_empty(&aio_req->osd_reqs)) {
950                         req = list_first_entry(&aio_req->osd_reqs,
951                                                struct ceph_osd_request,
952                                                r_unsafe_item);
953                         list_del_init(&req->r_unsafe_item);
954                         if (ret >= 0)
955                                 ret = ceph_osdc_start_request(req->r_osdc,
956                                                               req, false);
957                         if (ret < 0) {
958                                 req->r_result = ret;
959                                 ceph_aio_complete_req(req, NULL);
960                         }
961                 }
962                 return -EIOCBQUEUED;
963         }
964 
965         if (ret != -EOLDSNAPC && pos > iocb->ki_pos) {
966                 ret = pos - iocb->ki_pos;
967                 iocb->ki_pos = pos;
968         }
969         return ret;
970 }
971 
972 /*
973  * Synchronous write, straight from __user pointer or user pages.
974  *
975  * If write spans object boundary, just do multiple writes.  (For a
976  * correct atomic write, we should e.g. take write locks on all
977  * objects, rollback on failure, etc.)
978  */
979 static ssize_t
980 ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
981                 struct ceph_snap_context *snapc)
982 {
983         struct file *file = iocb->ki_filp;
984         struct inode *inode = file_inode(file);
985         struct ceph_inode_info *ci = ceph_inode(inode);
986         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
987         struct ceph_vino vino;
988         struct ceph_osd_request *req;
989         struct page **pages;
990         u64 len;
991         int num_pages;
992         int written = 0;
993         int flags;
994         int check_caps = 0;
995         int ret;
996         struct timespec mtime = current_fs_time(inode->i_sb);
997         size_t count = iov_iter_count(from);
998 
999         if (ceph_snap(file_inode(file)) != CEPH_NOSNAP)
1000                 return -EROFS;
1001 
1002         dout("sync_write on file %p %lld~%u\n", file, pos, (unsigned)count);
1003 
1004         ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + count);
1005         if (ret < 0)
1006                 return ret;
1007 
1008         ret = invalidate_inode_pages2_range(inode->i_mapping,
1009                                             pos >> PAGE_SHIFT,
1010                                             (pos + count) >> PAGE_SHIFT);
1011         if (ret < 0)
1012                 dout("invalidate_inode_pages2_range returned %d\n", ret);
1013 
1014         flags = CEPH_OSD_FLAG_ORDERSNAP |
1015                 CEPH_OSD_FLAG_ONDISK |
1016                 CEPH_OSD_FLAG_WRITE |
1017                 CEPH_OSD_FLAG_ACK;
1018 
1019         while ((len = iov_iter_count(from)) > 0) {
1020                 size_t left;
1021                 int n;
1022 
1023                 vino = ceph_vino(inode);
1024                 req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
1025                                             vino, pos, &len, 0, 1,
1026                                             CEPH_OSD_OP_WRITE, flags, snapc,
1027                                             ci->i_truncate_seq,
1028                                             ci->i_truncate_size,
1029                                             false);
1030                 if (IS_ERR(req)) {
1031                         ret = PTR_ERR(req);
1032                         break;
1033                 }
1034 
1035                 /*
1036                  * write from beginning of first page,
1037                  * regardless of io alignment
1038                  */
1039                 num_pages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1040 
1041                 pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
1042                 if (IS_ERR(pages)) {
1043                         ret = PTR_ERR(pages);
1044                         goto out;
1045                 }
1046 
1047                 left = len;
1048                 for (n = 0; n < num_pages; n++) {
1049                         size_t plen = min_t(size_t, left, PAGE_SIZE);
1050                         ret = copy_page_from_iter(pages[n], 0, plen, from);
1051                         if (ret != plen) {
1052                                 ret = -EFAULT;
1053                                 break;
1054                         }
1055                         left -= ret;
1056                 }
1057 
1058                 if (ret < 0) {
1059                         ceph_release_page_vector(pages, num_pages);
1060                         goto out;
1061                 }
1062 
1063                 /* get a second commit callback */
1064                 req->r_unsafe_callback = ceph_sync_write_unsafe;
1065                 req->r_inode = inode;
1066 
1067                 osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0,
1068                                                 false, true);
1069 
1070                 /* BUG_ON(vino.snap != CEPH_NOSNAP); */
1071                 ceph_osdc_build_request(req, pos, snapc, vino.snap, &mtime);
1072 
1073                 ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
1074                 if (!ret)
1075                         ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
1076 
1077 out:
1078                 ceph_osdc_put_request(req);
1079                 if (ret == 0) {
1080                         pos += len;
1081                         written += len;
1082 
1083                         if (pos > i_size_read(inode)) {
1084                                 check_caps = ceph_inode_set_size(inode, pos);
1085                                 if (check_caps)
1086                                         ceph_check_caps(ceph_inode(inode),
1087                                                         CHECK_CAPS_AUTHONLY,
1088                                                         NULL);
1089                         }
1090                 } else
1091                         break;
1092         }
1093 
1094         if (ret != -EOLDSNAPC && written > 0) {
1095                 ret = written;
1096                 iocb->ki_pos = pos;
1097         }
1098         return ret;
1099 }
1100 
1101 /*
1102  * Wrap generic_file_aio_read with checks for cap bits on the inode.
1103  * Atomically grab references, so that those bits are not released
1104  * back to the MDS mid-read.
1105  *
1106  * Hmm, the sync read case isn't actually async... should it be?
1107  */
1108 static ssize_t ceph_read_iter(struct kiocb *iocb, struct iov_iter *to)
1109 {
1110         struct file *filp = iocb->ki_filp;
1111         struct ceph_file_info *fi = filp->private_data;
1112         size_t len = iov_iter_count(to);
1113         struct inode *inode = file_inode(filp);
1114         struct ceph_inode_info *ci = ceph_inode(inode);
1115         struct page *pinned_page = NULL;
1116         ssize_t ret;
1117         int want, got = 0;
1118         int retry_op = 0, read = 0;
1119 
1120 again:
1121         dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
1122              inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len, inode);
1123 
1124         if (fi->fmode & CEPH_FILE_MODE_LAZY)
1125                 want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
1126         else
1127                 want = CEPH_CAP_FILE_CACHE;
1128         ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, -1, &got, &pinned_page);
1129         if (ret < 0)
1130                 return ret;
1131 
1132         if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
1133             (iocb->ki_flags & IOCB_DIRECT) ||
1134             (fi->flags & CEPH_F_SYNC)) {
1135 
1136                 dout("aio_sync_read %p %llx.%llx %llu~%u got cap refs on %s\n",
1137                      inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len,
1138                      ceph_cap_string(got));
1139 
1140                 if (ci->i_inline_version == CEPH_INLINE_NONE) {
1141                         if (!retry_op && (iocb->ki_flags & IOCB_DIRECT)) {
1142                                 ret = ceph_direct_read_write(iocb, to,
1143                                                              NULL, NULL);
1144                                 if (ret >= 0 && ret < len)
1145                                         retry_op = CHECK_EOF;
1146                         } else {
1147                                 ret = ceph_sync_read(iocb, to, &retry_op);
1148                         }
1149                 } else {
1150                         retry_op = READ_INLINE;
1151                 }
1152         } else {
1153                 dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
1154                      inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len,
1155                      ceph_cap_string(got));
1156 
1157                 ret = generic_file_read_iter(iocb, to);
1158         }
1159         dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
1160              inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
1161         if (pinned_page) {
1162                 put_page(pinned_page);
1163                 pinned_page = NULL;
1164         }
1165         ceph_put_cap_refs(ci, got);
1166         if (retry_op > HAVE_RETRIED && ret >= 0) {
1167                 int statret;
1168                 struct page *page = NULL;
1169                 loff_t i_size;
1170                 if (retry_op == READ_INLINE) {
1171                         page = __page_cache_alloc(GFP_KERNEL);
1172                         if (!page)
1173                                 return -ENOMEM;
1174                 }
1175 
1176                 statret = __ceph_do_getattr(inode, page,
1177                                             CEPH_STAT_CAP_INLINE_DATA, !!page);
1178                 if (statret < 0) {
1179                          __free_page(page);
1180                         if (statret == -ENODATA) {
1181                                 BUG_ON(retry_op != READ_INLINE);
1182                                 goto again;
1183                         }
1184                         return statret;
1185                 }
1186 
1187                 i_size = i_size_read(inode);
1188                 if (retry_op == READ_INLINE) {
1189                         BUG_ON(ret > 0 || read > 0);
1190                         if (iocb->ki_pos < i_size &&
1191                             iocb->ki_pos < PAGE_SIZE) {
1192                                 loff_t end = min_t(loff_t, i_size,
1193                                                    iocb->ki_pos + len);
1194                                 end = min_t(loff_t, end, PAGE_SIZE);
1195                                 if (statret < end)
1196                                         zero_user_segment(page, statret, end);
1197                                 ret = copy_page_to_iter(page,
1198                                                 iocb->ki_pos & ~PAGE_MASK,
1199                                                 end - iocb->ki_pos, to);
1200                                 iocb->ki_pos += ret;
1201                                 read += ret;
1202                         }
1203                         if (iocb->ki_pos < i_size && read < len) {
1204                                 size_t zlen = min_t(size_t, len - read,
1205                                                     i_size - iocb->ki_pos);
1206                                 ret = iov_iter_zero(zlen, to);
1207                                 iocb->ki_pos += ret;
1208                                 read += ret;
1209                         }
1210                         __free_pages(page, 0);
1211                         return read;
1212                 }
1213 
1214                 /* hit EOF or hole? */
1215                 if (retry_op == CHECK_EOF && iocb->ki_pos < i_size &&
1216                     ret < len) {
1217                         dout("sync_read hit hole, ppos %lld < size %lld"
1218                              ", reading more\n", iocb->ki_pos, i_size);
1219 
1220                         read += ret;
1221                         len -= ret;
1222                         retry_op = HAVE_RETRIED;
1223                         goto again;
1224                 }
1225         }
1226 
1227         if (ret >= 0)
1228                 ret += read;
1229 
1230         return ret;
1231 }
1232 
1233 /*
1234  * Take cap references to avoid releasing caps to MDS mid-write.
1235  *
1236  * If we are synchronous, and write with an old snap context, the OSD
1237  * may return EOLDSNAPC.  In that case, retry the write.. _after_
1238  * dropping our cap refs and allowing the pending snap to logically
1239  * complete _before_ this write occurs.
1240  *
1241  * If we are near ENOSPC, write synchronously.
1242  */
1243 static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
1244 {
1245         struct file *file = iocb->ki_filp;
1246         struct ceph_file_info *fi = file->private_data;
1247         struct inode *inode = file_inode(file);
1248         struct ceph_inode_info *ci = ceph_inode(inode);
1249         struct ceph_osd_client *osdc =
1250                 &ceph_sb_to_client(inode->i_sb)->client->osdc;
1251         struct ceph_cap_flush *prealloc_cf;
1252         ssize_t count, written = 0;
1253         int err, want, got;
1254         loff_t pos;
1255 
1256         if (ceph_snap(inode) != CEPH_NOSNAP)
1257                 return -EROFS;
1258 
1259         prealloc_cf = ceph_alloc_cap_flush();
1260         if (!prealloc_cf)
1261                 return -ENOMEM;
1262 
1263         inode_lock(inode);
1264 
1265         /* We can write back this queue in page reclaim */
1266         current->backing_dev_info = inode_to_bdi(inode);
1267 
1268         if (iocb->ki_flags & IOCB_APPEND) {
1269                 err = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE, false);
1270                 if (err < 0)
1271                         goto out;
1272         }
1273 
1274         err = generic_write_checks(iocb, from);
1275         if (err <= 0)
1276                 goto out;
1277 
1278         pos = iocb->ki_pos;
1279         count = iov_iter_count(from);
1280         err = file_remove_privs(file);
1281         if (err)
1282                 goto out;
1283 
1284         err = file_update_time(file);
1285         if (err)
1286                 goto out;
1287 
1288         if (ci->i_inline_version != CEPH_INLINE_NONE) {
1289                 err = ceph_uninline_data(file, NULL);
1290                 if (err < 0)
1291                         goto out;
1292         }
1293 
1294 retry_snap:
1295         if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL)) {
1296                 err = -ENOSPC;
1297                 goto out;
1298         }
1299 
1300         dout("aio_write %p %llx.%llx %llu~%zd getting caps. i_size %llu\n",
1301              inode, ceph_vinop(inode), pos, count, i_size_read(inode));
1302         if (fi->fmode & CEPH_FILE_MODE_LAZY)
1303                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
1304         else
1305                 want = CEPH_CAP_FILE_BUFFER;
1306         got = 0;
1307         err = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, pos + count,
1308                             &got, NULL);
1309         if (err < 0)
1310                 goto out;
1311 
1312         dout("aio_write %p %llx.%llx %llu~%zd got cap refs on %s\n",
1313              inode, ceph_vinop(inode), pos, count, ceph_cap_string(got));
1314 
1315         if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
1316             (iocb->ki_flags & IOCB_DIRECT) || (fi->flags & CEPH_F_SYNC)) {
1317                 struct ceph_snap_context *snapc;
1318                 struct iov_iter data;
1319                 inode_unlock(inode);
1320 
1321                 spin_lock(&ci->i_ceph_lock);
1322                 if (__ceph_have_pending_cap_snap(ci)) {
1323                         struct ceph_cap_snap *capsnap =
1324                                         list_last_entry(&ci->i_cap_snaps,
1325                                                         struct ceph_cap_snap,
1326                                                         ci_item);
1327                         snapc = ceph_get_snap_context(capsnap->context);
1328                 } else {
1329                         BUG_ON(!ci->i_head_snapc);
1330                         snapc = ceph_get_snap_context(ci->i_head_snapc);
1331                 }
1332                 spin_unlock(&ci->i_ceph_lock);
1333 
1334                 /* we might need to revert back to that point */
1335                 data = *from;
1336                 if (iocb->ki_flags & IOCB_DIRECT)
1337                         written = ceph_direct_read_write(iocb, &data, snapc,
1338                                                          &prealloc_cf);
1339                 else
1340                         written = ceph_sync_write(iocb, &data, pos, snapc);
1341                 if (written == -EOLDSNAPC) {
1342                         dout("aio_write %p %llx.%llx %llu~%u"
1343                                 "got EOLDSNAPC, retrying\n",
1344                                 inode, ceph_vinop(inode),
1345                                 pos, (unsigned)count);
1346                         inode_lock(inode);
1347                         goto retry_snap;
1348                 }
1349                 if (written > 0)
1350                         iov_iter_advance(from, written);
1351                 ceph_put_snap_context(snapc);
1352         } else {
1353                 loff_t old_size = i_size_read(inode);
1354                 /*
1355                  * No need to acquire the i_truncate_mutex. Because
1356                  * the MDS revokes Fwb caps before sending truncate
1357                  * message to us. We can't get Fwb cap while there
1358                  * are pending vmtruncate. So write and vmtruncate
1359                  * can not run at the same time
1360                  */
1361                 written = generic_perform_write(file, from, pos);
1362                 if (likely(written >= 0))
1363                         iocb->ki_pos = pos + written;
1364                 if (i_size_read(inode) > old_size)
1365                         ceph_fscache_update_objectsize(inode);
1366                 inode_unlock(inode);
1367         }
1368 
1369         if (written >= 0) {
1370                 int dirty;
1371                 spin_lock(&ci->i_ceph_lock);
1372                 ci->i_inline_version = CEPH_INLINE_NONE;
1373                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR,
1374                                                &prealloc_cf);
1375                 spin_unlock(&ci->i_ceph_lock);
1376                 if (dirty)
1377                         __mark_inode_dirty(inode, dirty);
1378         }
1379 
1380         dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
1381              inode, ceph_vinop(inode), pos, (unsigned)count,
1382              ceph_cap_string(got));
1383         ceph_put_cap_refs(ci, got);
1384 
1385         if (written >= 0 &&
1386             ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host) ||
1387              ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
1388                 err = vfs_fsync_range(file, pos, pos + written - 1, 1);
1389                 if (err < 0)
1390                         written = err;
1391         }
1392 
1393         goto out_unlocked;
1394 
1395 out:
1396         inode_unlock(inode);
1397 out_unlocked:
1398         ceph_free_cap_flush(prealloc_cf);
1399         current->backing_dev_info = NULL;
1400         return written ? written : err;
1401 }
1402 
1403 /*
1404  * llseek.  be sure to verify file size on SEEK_END.
1405  */
1406 static loff_t ceph_llseek(struct file *file, loff_t offset, int whence)
1407 {
1408         struct inode *inode = file->f_mapping->host;
1409         loff_t i_size;
1410         int ret;
1411 
1412         inode_lock(inode);
1413 
1414         if (whence == SEEK_END || whence == SEEK_DATA || whence == SEEK_HOLE) {
1415                 ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE, false);
1416                 if (ret < 0) {
1417                         offset = ret;
1418                         goto out;
1419                 }
1420         }
1421 
1422         i_size = i_size_read(inode);
1423         switch (whence) {
1424         case SEEK_END:
1425                 offset += i_size;
1426                 break;
1427         case SEEK_CUR:
1428                 /*
1429                  * Here we special-case the lseek(fd, 0, SEEK_CUR)
1430                  * position-querying operation.  Avoid rewriting the "same"
1431                  * f_pos value back to the file because a concurrent read(),
1432                  * write() or lseek() might have altered it
1433                  */
1434                 if (offset == 0) {
1435                         offset = file->f_pos;
1436                         goto out;
1437                 }
1438                 offset += file->f_pos;
1439                 break;
1440         case SEEK_DATA:
1441                 if (offset >= i_size) {
1442                         ret = -ENXIO;
1443                         goto out;
1444                 }
1445                 break;
1446         case SEEK_HOLE:
1447                 if (offset >= i_size) {
1448                         ret = -ENXIO;
1449                         goto out;
1450                 }
1451                 offset = i_size;
1452                 break;
1453         }
1454 
1455         offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
1456 
1457 out:
1458         inode_unlock(inode);
1459         return offset;
1460 }
1461 
1462 static inline void ceph_zero_partial_page(
1463         struct inode *inode, loff_t offset, unsigned size)
1464 {
1465         struct page *page;
1466         pgoff_t index = offset >> PAGE_SHIFT;
1467 
1468         page = find_lock_page(inode->i_mapping, index);
1469         if (page) {
1470                 wait_on_page_writeback(page);
1471                 zero_user(page, offset & (PAGE_SIZE - 1), size);
1472                 unlock_page(page);
1473                 put_page(page);
1474         }
1475 }
1476 
1477 static void ceph_zero_pagecache_range(struct inode *inode, loff_t offset,
1478                                       loff_t length)
1479 {
1480         loff_t nearly = round_up(offset, PAGE_SIZE);
1481         if (offset < nearly) {
1482                 loff_t size = nearly - offset;
1483                 if (length < size)
1484                         size = length;
1485                 ceph_zero_partial_page(inode, offset, size);
1486                 offset += size;
1487                 length -= size;
1488         }
1489         if (length >= PAGE_SIZE) {
1490                 loff_t size = round_down(length, PAGE_SIZE);
1491                 truncate_pagecache_range(inode, offset, offset + size - 1);
1492                 offset += size;
1493                 length -= size;
1494         }
1495         if (length)
1496                 ceph_zero_partial_page(inode, offset, length);
1497 }
1498 
1499 static int ceph_zero_partial_object(struct inode *inode,
1500                                     loff_t offset, loff_t *length)
1501 {
1502         struct ceph_inode_info *ci = ceph_inode(inode);
1503         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1504         struct ceph_osd_request *req;
1505         int ret = 0;
1506         loff_t zero = 0;
1507         int op;
1508 
1509         if (!length) {
1510                 op = offset ? CEPH_OSD_OP_DELETE : CEPH_OSD_OP_TRUNCATE;
1511                 length = &zero;
1512         } else {
1513                 op = CEPH_OSD_OP_ZERO;
1514         }
1515 
1516         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
1517                                         ceph_vino(inode),
1518                                         offset, length,
1519                                         0, 1, op,
1520                                         CEPH_OSD_FLAG_WRITE |
1521                                         CEPH_OSD_FLAG_ONDISK,
1522                                         NULL, 0, 0, false);
1523         if (IS_ERR(req)) {
1524                 ret = PTR_ERR(req);
1525                 goto out;
1526         }
1527 
1528         ceph_osdc_build_request(req, offset, NULL, ceph_vino(inode).snap,
1529                                 &inode->i_mtime);
1530 
1531         ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
1532         if (!ret) {
1533                 ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
1534                 if (ret == -ENOENT)
1535                         ret = 0;
1536         }
1537         ceph_osdc_put_request(req);
1538 
1539 out:
1540         return ret;
1541 }
1542 
1543 static int ceph_zero_objects(struct inode *inode, loff_t offset, loff_t length)
1544 {
1545         int ret = 0;
1546         struct ceph_inode_info *ci = ceph_inode(inode);
1547         s32 stripe_unit = ceph_file_layout_su(ci->i_layout);
1548         s32 stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
1549         s32 object_size = ceph_file_layout_object_size(ci->i_layout);
1550         u64 object_set_size = object_size * stripe_count;
1551         u64 nearly, t;
1552 
1553         /* round offset up to next period boundary */
1554         nearly = offset + object_set_size - 1;
1555         t = nearly;
1556         nearly -= do_div(t, object_set_size);
1557 
1558         while (length && offset < nearly) {
1559                 loff_t size = length;
1560                 ret = ceph_zero_partial_object(inode, offset, &size);
1561                 if (ret < 0)
1562                         return ret;
1563                 offset += size;
1564                 length -= size;
1565         }
1566         while (length >= object_set_size) {
1567                 int i;
1568                 loff_t pos = offset;
1569                 for (i = 0; i < stripe_count; ++i) {
1570                         ret = ceph_zero_partial_object(inode, pos, NULL);
1571                         if (ret < 0)
1572                                 return ret;
1573                         pos += stripe_unit;
1574                 }
1575                 offset += object_set_size;
1576                 length -= object_set_size;
1577         }
1578         while (length) {
1579                 loff_t size = length;
1580                 ret = ceph_zero_partial_object(inode, offset, &size);
1581                 if (ret < 0)
1582                         return ret;
1583                 offset += size;
1584                 length -= size;
1585         }
1586         return ret;
1587 }
1588 
1589 static long ceph_fallocate(struct file *file, int mode,
1590                                 loff_t offset, loff_t length)
1591 {
1592         struct ceph_file_info *fi = file->private_data;
1593         struct inode *inode = file_inode(file);
1594         struct ceph_inode_info *ci = ceph_inode(inode);
1595         struct ceph_osd_client *osdc =
1596                 &ceph_inode_to_client(inode)->client->osdc;
1597         struct ceph_cap_flush *prealloc_cf;
1598         int want, got = 0;
1599         int dirty;
1600         int ret = 0;
1601         loff_t endoff = 0;
1602         loff_t size;
1603 
1604         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
1605                 return -EOPNOTSUPP;
1606 
1607         if (!S_ISREG(inode->i_mode))
1608                 return -EOPNOTSUPP;
1609 
1610         prealloc_cf = ceph_alloc_cap_flush();
1611         if (!prealloc_cf)
1612                 return -ENOMEM;
1613 
1614         inode_lock(inode);
1615 
1616         if (ceph_snap(inode) != CEPH_NOSNAP) {
1617                 ret = -EROFS;
1618                 goto unlock;
1619         }
1620 
1621         if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL) &&
1622                 !(mode & FALLOC_FL_PUNCH_HOLE)) {
1623                 ret = -ENOSPC;
1624                 goto unlock;
1625         }
1626 
1627         if (ci->i_inline_version != CEPH_INLINE_NONE) {
1628                 ret = ceph_uninline_data(file, NULL);
1629                 if (ret < 0)
1630                         goto unlock;
1631         }
1632 
1633         size = i_size_read(inode);
1634         if (!(mode & FALLOC_FL_KEEP_SIZE))
1635                 endoff = offset + length;
1636 
1637         if (fi->fmode & CEPH_FILE_MODE_LAZY)
1638                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
1639         else
1640                 want = CEPH_CAP_FILE_BUFFER;
1641 
1642         ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, endoff, &got, NULL);
1643         if (ret < 0)
1644                 goto unlock;
1645 
1646         if (mode & FALLOC_FL_PUNCH_HOLE) {
1647                 if (offset < size)
1648                         ceph_zero_pagecache_range(inode, offset, length);
1649                 ret = ceph_zero_objects(inode, offset, length);
1650         } else if (endoff > size) {
1651                 truncate_pagecache_range(inode, size, -1);
1652                 if (ceph_inode_set_size(inode, endoff))
1653                         ceph_check_caps(ceph_inode(inode),
1654                                 CHECK_CAPS_AUTHONLY, NULL);
1655         }
1656 
1657         if (!ret) {
1658                 spin_lock(&ci->i_ceph_lock);
1659                 ci->i_inline_version = CEPH_INLINE_NONE;
1660                 dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR,
1661                                                &prealloc_cf);
1662                 spin_unlock(&ci->i_ceph_lock);
1663                 if (dirty)
1664                         __mark_inode_dirty(inode, dirty);
1665         }
1666 
1667         ceph_put_cap_refs(ci, got);
1668 unlock:
1669         inode_unlock(inode);
1670         ceph_free_cap_flush(prealloc_cf);
1671         return ret;
1672 }
1673 
1674 const struct file_operations ceph_file_fops = {
1675         .open = ceph_open,
1676         .release = ceph_release,
1677         .llseek = ceph_llseek,
1678         .read_iter = ceph_read_iter,
1679         .write_iter = ceph_write_iter,
1680         .mmap = ceph_mmap,
1681         .fsync = ceph_fsync,
1682         .lock = ceph_lock,
1683         .flock = ceph_flock,
1684         .splice_read = generic_file_splice_read,
1685         .splice_write = iter_file_splice_write,
1686         .unlocked_ioctl = ceph_ioctl,
1687         .compat_ioctl   = ceph_ioctl,
1688         .fallocate      = ceph_fallocate,
1689 };
1690 
1691 

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