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1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2  * vim:expandtab:shiftwidth=8:tabstop=8:
3  *
4  *  Copyright (c) 2001-2003 Cluster File Systems, Inc.
5  *
6  *   This file is part of Lustre, http://www.lustre.org.
7  *
8  *   Lustre is free software; you can redistribute it and/or
9  *   modify it under the terms of version 2 of the GNU General Public
10  *   License as published by the Free Software Foundation.
11  *
12  *   Lustre is distributed in the hope that it will be useful,
13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *   GNU General Public License for more details.
16  *
17  *   You should have received a copy of the GNU General Public License
18  *   along with Lustre; if not, write to the Free Software
19  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20  */
21
22 #ifndef AUTOCONF_INCLUDED
23 #include <linux/config.h>
24 #endif
25 #include <linux/kernel.h>
26 #include <linux/mm.h>
27 #include <linux/string.h>
28 #include <linux/stat.h>
29 #include <linux/errno.h>
30 #include <linux/smp_lock.h>
31 #include <linux/unistd.h>
32 #include <linux/version.h>
33 #include <asm/system.h>
34 #include <asm/uaccess.h>
35
36 #include <linux/fs.h>
37 #include <linux/stat.h>
38 #include <asm/uaccess.h>
39 #include <linux/mm.h>
40 #include <linux/pagemap.h>
41 #include <linux/smp_lock.h>
42
43 #define DEBUG_SUBSYSTEM S_LLITE
44
45 //#include <lustre_mdc.h>
46 #include <lustre_lite.h>
47 #include "llite_internal.h"
48 #include <linux/lustre_compat25.h>
49
50 #define VMA_DEBUG(vma, fmt, arg...)                                     \
51         CDEBUG(D_MMAP, "vma(%p) start(%ld) end(%ld) pgoff(%ld) inode(%p) "   \
52                "ino(%lu) iname(%s): " fmt, vma, vma->vm_start, vma->vm_end,  \
53                vma->vm_pgoff, vma->vm_file->f_dentry->d_inode,               \
54                vma->vm_file->f_dentry->d_inode->i_ino,                       \
55                vma->vm_file->f_dentry->d_iname, ## arg);                     \
56
57
58 struct ll_lock_tree_node {
59         rb_node_t               lt_node;
60         struct list_head        lt_locked_item;
61         __u64                   lt_oid;
62         ldlm_policy_data_t      lt_policy;
63         struct lustre_handle    lt_lockh;
64         ldlm_mode_t             lt_mode;
65         struct inode           *lt_inode;
66 };
67
68 int lt_get_mmap_locks(struct ll_lock_tree *tree,
69                       unsigned long addr, size_t count);
70
71 struct page *ll_nopage(struct vm_area_struct *vma, unsigned long address,
72                        int *type);
73
74 struct ll_lock_tree_node * ll_node_from_inode(struct inode *inode, __u64 start,
75                                               __u64 end, ldlm_mode_t mode)
76 {
77         struct ll_lock_tree_node *node;
78
79         OBD_ALLOC(node, sizeof(*node));
80         if (node == NULL)
81                 RETURN(ERR_PTR(-ENOMEM));
82
83         node->lt_inode = inode;
84         node->lt_oid = ll_i2info(inode)->lli_smd->lsm_object_id;
85         node->lt_policy.l_extent.start = start;
86         node->lt_policy.l_extent.end = end;
87         memset(&node->lt_lockh, 0, sizeof(node->lt_lockh));
88         INIT_LIST_HEAD(&node->lt_locked_item);
89         node->lt_mode = mode;
90
91         return node;
92 }
93
94 int lt_compare(struct ll_lock_tree_node *one, struct ll_lock_tree_node *two)
95 {
96         /* To avoid multiple fs deadlock */
97         if (one->lt_inode->i_sb->s_dev < two->lt_inode->i_sb->s_dev)
98                 return -1;
99         if (one->lt_inode->i_sb->s_dev > two->lt_inode->i_sb->s_dev)
100                 return 1;
101
102         if (one->lt_oid < two->lt_oid)
103                 return -1;
104         if (one->lt_oid > two->lt_oid)
105                 return 1;
106
107         if (one->lt_policy.l_extent.end < two->lt_policy.l_extent.start)
108                 return -1;
109         if (one->lt_policy.l_extent.start > two->lt_policy.l_extent.end)
110                 return 1;
111
112         return 0; /* they are the same object and overlap */
113 }
114
115 static void lt_merge(struct ll_lock_tree_node *dst,
116                      struct ll_lock_tree_node *src)
117 {
118         dst->lt_policy.l_extent.start = min(dst->lt_policy.l_extent.start,
119                                             src->lt_policy.l_extent.start);
120         dst->lt_policy.l_extent.end = max(dst->lt_policy.l_extent.end,
121                                           src->lt_policy.l_extent.end);
122
123         /* XXX could be a real call to the dlm to find superset modes */
124         if (src->lt_mode == LCK_PW && dst->lt_mode != LCK_PW)
125                 dst->lt_mode = LCK_PW;
126 }
127
128 static void lt_insert(struct ll_lock_tree *tree,
129                       struct ll_lock_tree_node *node)
130 {
131         struct ll_lock_tree_node *walk;
132         rb_node_t **p, *parent;
133         ENTRY;
134
135 restart:
136         p = &tree->lt_root.rb_node;
137         parent = NULL;
138         while (*p) {
139                 parent = *p;
140                 walk = rb_entry(parent, struct ll_lock_tree_node, lt_node);
141                 switch (lt_compare(node, walk)) {
142                 case -1:
143                         p = &(*p)->rb_left;
144                         break;
145                 case 1:
146                         p = &(*p)->rb_right;
147                         break;
148                 case 0:
149                         lt_merge(node, walk);
150                         rb_erase(&walk->lt_node, &tree->lt_root);
151                         OBD_FREE(walk, sizeof(*walk));
152                         goto restart;
153                         break;
154                 default:
155                         LBUG();
156                         break;
157                 }
158         }
159         rb_link_node(&node->lt_node, parent, p);
160         rb_insert_color(&node->lt_node, &tree->lt_root);
161         EXIT;
162 }
163
164 static struct ll_lock_tree_node *lt_least_node(struct ll_lock_tree *tree)
165 {
166         rb_node_t *rbnode;
167         struct ll_lock_tree_node *node = NULL;
168
169         for ( rbnode = tree->lt_root.rb_node; rbnode != NULL;
170               rbnode = rbnode->rb_left) {
171                 if (rbnode->rb_left == NULL) {
172                         node = rb_entry(rbnode, struct ll_lock_tree_node,
173                                         lt_node);
174                         break;
175                 }
176         }
177         RETURN(node);
178 }
179
180 int ll_tree_unlock(struct ll_lock_tree *tree)
181 {
182         struct ll_lock_tree_node *node;
183         struct list_head *pos, *n;
184         struct inode *inode;
185         int rc = 0;
186         ENTRY;
187
188         list_for_each_safe(pos, n, &tree->lt_locked_list) {
189                 node = list_entry(pos, struct ll_lock_tree_node,
190                                   lt_locked_item);
191
192                 inode = node->lt_inode;
193                 rc = ll_extent_unlock(tree->lt_fd, inode,
194                                       ll_i2info(inode)->lli_smd, node->lt_mode,
195                                       &node->lt_lockh);
196                 if (rc != 0) {
197                         /* XXX better message */
198                         CERROR("couldn't unlock %d\n", rc);
199                 }
200                 list_del(&node->lt_locked_item);
201                 OBD_FREE(node, sizeof(*node));
202         }
203
204         while ((node = lt_least_node(tree))) {
205                 rb_erase(&node->lt_node, &tree->lt_root);
206                 OBD_FREE(node, sizeof(*node));
207         }
208
209         RETURN(rc);
210 }
211
212 int ll_tree_lock(struct ll_lock_tree *tree,
213                  struct ll_lock_tree_node *first_node,
214                  const char *buf, size_t count, int ast_flags)
215 {
216         struct ll_lock_tree_node *node;
217         int rc = 0;
218         ENTRY;
219
220         tree->lt_root.rb_node = NULL;
221         INIT_LIST_HEAD(&tree->lt_locked_list);
222         if (first_node != NULL)
223                 lt_insert(tree, first_node);
224
225         /* To avoid such subtle deadlock case: client1 try to read file1 to
226          * mmapped file2, on the same time, client2 try to read file2 to
227          * mmapped file1.*/
228         rc = lt_get_mmap_locks(tree, (unsigned long)buf, count);
229         if (rc)
230                 GOTO(out, rc);
231
232         while ((node = lt_least_node(tree))) {
233                 struct inode *inode = node->lt_inode;
234                 rc = ll_extent_lock(tree->lt_fd, inode,
235                                     ll_i2info(inode)->lli_smd, node->lt_mode,
236                                     &node->lt_policy, &node->lt_lockh,
237                                     ast_flags);
238                 if (rc != 0)
239                         GOTO(out, rc);
240
241                 rb_erase(&node->lt_node, &tree->lt_root);
242                 list_add_tail(&node->lt_locked_item, &tree->lt_locked_list);
243         }
244         RETURN(rc);
245 out:
246         ll_tree_unlock(tree);
247         RETURN(rc);
248 }
249
250 static ldlm_mode_t mode_from_vma(struct vm_area_struct *vma)
251 {
252         /* we only want to hold PW locks if the mmap() can generate
253          * writes back to the file and that only happens in shared
254          * writable vmas */
255         if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
256                 return LCK_PW;
257         return LCK_PR;
258 }
259
260 static void policy_from_vma(ldlm_policy_data_t *policy,
261                             struct vm_area_struct *vma, unsigned long addr,
262                             size_t count)
263 {
264         policy->l_extent.start = ((addr - vma->vm_start) & CFS_PAGE_MASK) +
265                                  (vma->vm_pgoff << CFS_PAGE_SHIFT);
266         policy->l_extent.end = (policy->l_extent.start + count - 1) |
267                                ~CFS_PAGE_MASK;
268 }
269
270 static struct vm_area_struct * our_vma(unsigned long addr, size_t count)
271 {
272         struct mm_struct *mm = current->mm;
273         struct vm_area_struct *vma, *ret = NULL;
274         ENTRY;
275
276         /* No MM (e.g. NFS)? No vmas too. */
277         if (!mm)
278                 RETURN(NULL);
279
280         spin_lock(&mm->page_table_lock);
281         for(vma = find_vma(mm, addr);
282             vma != NULL && vma->vm_start < (addr + count); vma = vma->vm_next) {
283                 if (vma->vm_ops && vma->vm_ops->nopage == ll_nopage &&
284                     vma->vm_flags & VM_SHARED) {
285                         ret = vma;
286                         break;
287                 }
288         }
289         spin_unlock(&mm->page_table_lock);
290         RETURN(ret);
291 }
292
293 int ll_region_mapped(unsigned long addr, size_t count)
294 {
295         return !!our_vma(addr, count);
296 }
297
298 int lt_get_mmap_locks(struct ll_lock_tree *tree,
299                       unsigned long addr, size_t count)
300 {
301         struct vm_area_struct *vma;
302         struct ll_lock_tree_node *node;
303         ldlm_policy_data_t policy;
304         struct inode *inode;
305         ENTRY;
306
307         if (count == 0)
308                 RETURN(0);
309
310         /* we need to look up vmas on page aligned addresses */
311         count += addr & (~CFS_PAGE_MASK);
312         addr &= CFS_PAGE_MASK;
313
314         while ((vma = our_vma(addr, count)) != NULL) {
315                 LASSERT(vma->vm_file);
316
317                 inode = vma->vm_file->f_dentry->d_inode;
318                 policy_from_vma(&policy, vma, addr, count);
319                 node = ll_node_from_inode(inode, policy.l_extent.start,
320                                           policy.l_extent.end,
321                                           mode_from_vma(vma));
322                 if (IS_ERR(node)) {
323                         CERROR("not enough mem for lock_tree_node!\n");
324                         RETURN(-ENOMEM);
325                 }
326                 lt_insert(tree, node);
327
328                 if (vma->vm_end - addr >= count)
329                         break;
330                 count -= vma->vm_end - addr;
331                 addr = vma->vm_end;
332         }
333         RETURN(0);
334 }
335
336 /**
337  * Page fault handler.
338  *
339  * \param vma - is virtiual area struct related to page fault
340  * \param address - address when hit fault
341  * \param type - of fault
342  *
343  * \return allocated and filled page for address
344  * \retval NOPAGE_SIGBUS if page not exist on this address
345  * \retval NOPAGE_OOM not have memory for allocate new page
346  */
347 struct page *ll_nopage(struct vm_area_struct *vma, unsigned long address,
348                        int *type)
349 {
350         struct file *filp = vma->vm_file;
351         struct ll_file_data *fd = LUSTRE_FPRIVATE(filp);
352         struct inode *inode = filp->f_dentry->d_inode;
353         struct lustre_handle lockh = { 0 };
354         ldlm_policy_data_t policy;
355         ldlm_mode_t mode;
356         struct page *page = NULL;
357         struct ll_inode_info *lli = ll_i2info(inode);
358         struct lov_stripe_md *lsm;
359         struct ost_lvb lvb;
360         __u64 kms, old_mtime;
361         unsigned long pgoff, size, rand_read, seq_read;
362         int rc = 0;
363         ENTRY;
364
365         if (lli->lli_smd == NULL) {
366                 CERROR("No lsm on fault?\n");
367                 RETURN(NULL);
368         }
369
370         ll_clear_file_contended(inode);
371
372         /* start and end the lock on the first and last bytes in the page */
373         policy_from_vma(&policy, vma, address, CFS_PAGE_SIZE);
374
375         CDEBUG(D_MMAP, "nopage vma %p inode %lu, locking ["LPU64", "LPU64"]\n",
376                vma, inode->i_ino, policy.l_extent.start, policy.l_extent.end);
377
378         mode = mode_from_vma(vma);
379         old_mtime = LTIME_S(inode->i_mtime);
380
381         lsm = lli->lli_smd;
382         rc = ll_extent_lock(fd, inode, lsm, mode, &policy,
383                             &lockh, LDLM_FL_CBPENDING | LDLM_FL_NO_LRU);
384         if (rc != 0)
385                 RETURN(NULL);
386
387         if (vma->vm_flags & VM_EXEC && LTIME_S(inode->i_mtime) != old_mtime)
388                 CWARN("binary changed. inode %lu\n", inode->i_ino);
389
390         lov_stripe_lock(lsm);
391         inode_init_lvb(inode, &lvb);
392         obd_merge_lvb(ll_i2dtexp(inode), lsm, &lvb, 1);
393         kms = lvb.lvb_size;
394
395         pgoff = ((address - vma->vm_start) >> CFS_PAGE_SHIFT) + vma->vm_pgoff;
396         size = (kms + CFS_PAGE_SIZE - 1) >> CFS_PAGE_SHIFT;
397
398         if (pgoff >= size) {
399                 lov_stripe_unlock(lsm);
400                 ll_glimpse_size(inode, LDLM_FL_BLOCK_GRANTED);
401         } else {
402                 /* XXX change inode size without ll_inode_size_lock() held!
403                  *     there is a race condition with truncate path. (see
404                  *     ll_extent_lock) */
405                 /* XXX i_size_write() is not used because it is not safe to
406                  *     take the ll_inode_size_lock() due to a potential lock
407                  *     inversion (bug 6077).  And since it's not safe to use
408                  *     i_size_write() without a covering mutex we do the
409                  *     assignment directly.  It is not critical that the
410                  *     size be correct. */
411                 /* region is within kms and, hence, within real file size (A).
412                  * We need to increase i_size to cover the read region so that
413                  * generic_file_read() will do its job, but that doesn't mean
414                  * the kms size is _correct_, it is only the _minimum_ size.
415                  * If someone does a stat they will get the correct size which
416                  * will always be >= the kms value here.  b=11081 */
417                 if (i_size_read(inode) < kms) {
418                         inode->i_size = kms;
419                         CDEBUG(D_INODE, "ino=%lu, updating i_size %llu\n",
420                                inode->i_ino, i_size_read(inode));
421                 }
422                 lov_stripe_unlock(lsm);
423         }
424
425         /* If mapping is writeable, adjust kms to cover this page,
426          * but do not extend kms beyond actual file size.
427          * policy.l_extent.end is set to the end of the page by policy_from_vma
428          * bug 10919 */
429         lov_stripe_lock(lsm);
430         if (mode == LCK_PW)
431                 obd_adjust_kms(ll_i2dtexp(inode), lsm,
432                                min_t(loff_t, policy.l_extent.end + 1,
433                                i_size_read(inode)), 0);
434         lov_stripe_unlock(lsm);
435
436         /* disable VM_SEQ_READ and use VM_RAND_READ to make sure that
437          * the kernel will not read other pages not covered by ldlm in
438          * filemap_nopage. we do our readahead in ll_readpage.
439          */
440         rand_read = vma->vm_flags & VM_RAND_READ;
441         seq_read = vma->vm_flags & VM_SEQ_READ;
442         vma->vm_flags &= ~ VM_SEQ_READ;
443         vma->vm_flags |= VM_RAND_READ;
444
445         page = filemap_nopage(vma, address, type);
446         if (page != NOPAGE_SIGBUS && page != NOPAGE_OOM)
447                 LL_CDEBUG_PAGE(D_PAGE, page, "got addr %lu type %lx\n", address,
448                                (long)type);
449         else
450                 CDEBUG(D_PAGE, "got addr %lu type %lx - SIGBUS\n",  address,
451                                (long)type);
452
453         vma->vm_flags &= ~VM_RAND_READ;
454         vma->vm_flags |= (rand_read | seq_read);
455
456         ll_extent_unlock(fd, inode, ll_i2info(inode)->lli_smd, mode, &lockh);
457         RETURN(page);
458 }
459
460 /* To avoid cancel the locks covering mmapped region for lock cache pressure,
461  * we track the mapped vma count by lli_mmap_cnt.
462  * ll_vm_open():  when first vma is linked, split locks from lru.
463  * ll_vm_close(): when last vma is unlinked, join all this file's locks to lru.
464  *
465  * XXX we don't check the if the region of vma/lock for performance.
466  */
467 static void ll_vm_open(struct vm_area_struct * vma)
468 {
469         struct inode *inode = vma->vm_file->f_dentry->d_inode;
470         struct ll_inode_info *lli = ll_i2info(inode);
471         ENTRY;
472
473         LASSERT(vma->vm_file);
474
475         spin_lock(&lli->lli_lock);
476         LASSERT(atomic_read(&lli->lli_mmap_cnt) >= 0);
477
478         atomic_inc(&lli->lli_mmap_cnt);
479         if (atomic_read(&lli->lli_mmap_cnt) == 1) {
480                 struct lov_stripe_md *lsm = lli->lli_smd;
481                 struct ll_sb_info *sbi = ll_i2sbi(inode);
482                 int count;
483
484                 spin_unlock(&lli->lli_lock);
485
486                 if (!lsm)
487                         return;
488                 count = obd_join_lru(sbi->ll_dt_exp, lsm, 0);
489                 VMA_DEBUG(vma, "split %d unused locks from lru\n", count);
490         } else {
491                 spin_unlock(&lli->lli_lock);
492         }
493
494 }
495
496 static void ll_vm_close(struct vm_area_struct *vma)
497 {
498         struct inode *inode = vma->vm_file->f_dentry->d_inode;
499         struct ll_inode_info *lli = ll_i2info(inode);
500         ENTRY;
501
502         LASSERT(vma->vm_file);
503
504         spin_lock(&lli->lli_lock);
505         LASSERT(atomic_read(&lli->lli_mmap_cnt) > 0);
506
507         atomic_dec(&lli->lli_mmap_cnt);
508         if (atomic_read(&lli->lli_mmap_cnt) == 0) {
509                 struct lov_stripe_md *lsm = lli->lli_smd;
510                 struct ll_sb_info *sbi = ll_i2sbi(inode);
511                 int count;
512
513                 spin_unlock(&lli->lli_lock);
514
515                 if (!lsm)
516                         return;
517                 count = obd_join_lru(sbi->ll_dt_exp, lsm, 1);
518                 VMA_DEBUG(vma, "join %d unused locks to lru\n", count);
519         } else {
520                 spin_unlock(&lli->lli_lock);
521         }
522 }
523
524 #ifndef HAVE_FILEMAP_POPULATE
525 static int (*filemap_populate)(struct vm_area_struct * area, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock);
526 #endif
527 static int ll_populate(struct vm_area_struct *area, unsigned long address,
528                        unsigned long len, pgprot_t prot, unsigned long pgoff,
529                        int nonblock)
530 {
531         int rc = 0;
532         ENTRY;
533
534         /* always set nonblock as true to avoid page read ahead */
535         rc = filemap_populate(area, address, len, prot, pgoff, 1);
536         RETURN(rc);
537 }
538
539 /* return the user space pointer that maps to a file offset via a vma */
540 static inline unsigned long file_to_user(struct vm_area_struct *vma, __u64 byte)
541 {
542         return vma->vm_start + (byte - ((__u64)vma->vm_pgoff << CFS_PAGE_SHIFT));
543
544 }
545
546 /* XXX put nice comment here.  talk about __free_pte -> dirty pages and
547  * nopage's reference passing to the pte */
548 int ll_teardown_mmaps(struct address_space *mapping, __u64 first, __u64 last)
549 {
550         int rc = -ENOENT;
551         ENTRY;
552
553         LASSERTF(last > first, "last "LPU64" first "LPU64"\n", last, first);
554         if (mapping_mapped(mapping)) {
555                 rc = 0;
556                 unmap_mapping_range(mapping, first + CFS_PAGE_SIZE - 1,
557                                     last - first + 1, 0);
558         }
559
560         RETURN(rc);
561 }
562
563 static struct vm_operations_struct ll_file_vm_ops = {
564         .nopage         = ll_nopage,
565         .open           = ll_vm_open,
566         .close          = ll_vm_close,
567         .populate       = ll_populate,
568 };
569
570 int ll_file_mmap(struct file * file, struct vm_area_struct * vma)
571 {
572         int rc;
573         ENTRY;
574
575         ll_stats_ops_tally(ll_i2sbi(file->f_dentry->d_inode), LPROC_LL_MAP, 1);
576         rc = generic_file_mmap(file, vma);
577         if (rc == 0) {
578 #if !defined(HAVE_FILEMAP_POPULATE)
579                 if (!filemap_populate)
580                         filemap_populate = vma->vm_ops->populate;
581 #endif
582                 vma->vm_ops = &ll_file_vm_ops;
583                 vma->vm_ops->open(vma);
584                 /* update the inode's size and mtime */
585                 rc = ll_glimpse_size(file->f_dentry->d_inode, 0);
586         }
587
588         RETURN(rc);
589 }