1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
4 * Copyright (c) 2001-2003 Cluster File Systems, Inc.
6 * This file is part of Lustre, http://www.lustre.org.
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.
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.
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.
22 #include <linux/config.h>
23 #include <linux/kernel.h>
25 #include <linux/string.h>
26 #include <linux/stat.h>
27 #include <linux/errno.h>
28 #include <linux/smp_lock.h>
29 #include <linux/unistd.h>
30 #include <linux/version.h>
31 #include <asm/system.h>
32 #include <asm/uaccess.h>
35 #include <linux/stat.h>
36 #include <asm/uaccess.h>
37 #include <asm/segment.h>
39 #include <linux/pagemap.h>
40 #include <linux/smp_lock.h>
41 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
42 #include <linux/iobuf.h>
45 #define DEBUG_SUBSYSTEM S_LLITE
47 #include <linux/lustre_mds.h>
48 #include <linux/lustre_lite.h>
49 #include "llite_internal.h"
50 #include <linux/lustre_compat25.h>
53 struct ll_lock_tree_node {
55 struct list_head lt_locked_item;
57 ldlm_policy_data_t lt_policy;
58 struct lustre_handle lt_lockh;
62 __u64 lov_merge_size(struct lov_stripe_md *lsm, int kms);
63 int lt_get_mmap_locks(struct ll_lock_tree *tree, struct inode *inode,
64 unsigned long addr, size_t count);
65 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0))
66 struct page *ll_nopage(struct vm_area_struct *vma, unsigned long address,
69 struct page *ll_nopage(struct vm_area_struct *vma, unsigned long address,
73 struct ll_lock_tree_node * ll_node_from_inode(struct inode *inode, __u64 start,
74 __u64 end, ldlm_mode_t mode)
76 struct ll_lock_tree_node *node;
78 OBD_ALLOC(node, sizeof(*node));
80 RETURN(ERR_PTR(-ENOMEM));
82 node->lt_oid = ll_i2info(inode)->lli_smd->lsm_object_id;
83 node->lt_policy.l_extent.start = start;
84 node->lt_policy.l_extent.end = end;
85 memset(&node->lt_lockh, 0, sizeof(node->lt_lockh));
86 INIT_LIST_HEAD(&node->lt_locked_item);
92 int lt_compare(struct ll_lock_tree_node *one, struct ll_lock_tree_node *two)
94 if ( one->lt_oid < two->lt_oid)
96 if ( one->lt_oid > two->lt_oid)
99 if ( one->lt_policy.l_extent.end < two->lt_policy.l_extent.start )
101 if ( one->lt_policy.l_extent.start > two->lt_policy.l_extent.end )
104 return 0; /* they are the same object and overlap */
107 static void lt_merge(struct ll_lock_tree_node *dst,
108 struct ll_lock_tree_node *src)
110 dst->lt_policy.l_extent.start = min(dst->lt_policy.l_extent.start,
111 src->lt_policy.l_extent.start);
112 dst->lt_policy.l_extent.end = max(dst->lt_policy.l_extent.end,
113 src->lt_policy.l_extent.end);
115 /* XXX could be a real call to the dlm to find superset modes */
116 if (src->lt_mode == LCK_PW && dst->lt_mode != LCK_PW)
117 dst->lt_mode = LCK_PW;
120 static void lt_insert(struct ll_lock_tree *tree,
121 struct ll_lock_tree_node *node)
123 struct ll_lock_tree_node *walk;
124 rb_node_t **p, *parent;
128 p = &tree->lt_root.rb_node;
132 walk = rb_entry(parent, struct ll_lock_tree_node, lt_node);
133 switch (lt_compare(node, walk)) {
141 lt_merge(node, walk);
142 rb_erase(&walk->lt_node, &tree->lt_root);
143 OBD_FREE(walk, sizeof(*walk));
151 rb_link_node(&node->lt_node, parent, p);
152 rb_insert_color(&node->lt_node, &tree->lt_root);
156 static struct ll_lock_tree_node *lt_least_node(struct ll_lock_tree *tree)
159 struct ll_lock_tree_node *node = NULL;
161 for ( rbnode = tree->lt_root.rb_node; rbnode != NULL;
162 rbnode = rbnode->rb_left) {
163 if (rbnode->rb_left == NULL) {
164 node = rb_entry(rbnode, struct ll_lock_tree_node,
172 int ll_tree_unlock(struct ll_lock_tree *tree, struct inode *inode)
174 struct ll_lock_tree_node *node;
175 struct list_head *pos, *n;
179 list_for_each_safe(pos, n, &tree->lt_locked_list) {
180 node = list_entry(pos, struct ll_lock_tree_node,
183 rc = ll_extent_unlock(tree->lt_fd, inode,
184 ll_i2info(inode)->lli_smd, node->lt_mode,
187 /* XXX better message */
188 CERROR("couldn't unlock %d\n", rc);
190 list_del(&node->lt_locked_item);
191 OBD_FREE(node, sizeof(*node));
194 while ((node = lt_least_node(tree))) {
195 rb_erase(&node->lt_node, &tree->lt_root);
196 OBD_FREE(node, sizeof(*node));
202 int ll_tree_lock(struct ll_lock_tree *tree,
203 struct ll_lock_tree_node *first_node, struct inode *inode,
204 const char *buf, size_t count, int ast_flags)
206 struct ll_lock_tree_node *node;
210 tree->lt_root.rb_node = NULL;
211 INIT_LIST_HEAD(&tree->lt_locked_list);
212 if (first_node != NULL)
213 lt_insert(tree, first_node);
215 if (mapping_mapped(inode->i_mapping)) {
216 rc = lt_get_mmap_locks(tree, inode, (unsigned long)buf, count);
221 while ((node = lt_least_node(tree))) {
222 struct obd_service_time *stime;
223 stime = (node->lt_mode & LCK_PW) ?
224 &ll_i2sbi(inode)->ll_write_stime :
225 &ll_i2sbi(inode)->ll_read_stime;
227 rc = ll_extent_lock(tree->lt_fd, inode,
228 ll_i2info(inode)->lli_smd, node->lt_mode,
229 &node->lt_policy, &node->lt_lockh,
234 rb_erase(&node->lt_node, &tree->lt_root);
235 list_add_tail(&node->lt_locked_item, &tree->lt_locked_list);
239 ll_tree_unlock(tree, inode);
243 static ldlm_mode_t mode_from_vma(struct vm_area_struct *vma)
245 /* we only want to hold PW locks if the mmap() can generate
246 * writes back to the file and that only happens in shared
248 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
253 static void policy_from_vma(ldlm_policy_data_t *policy,
254 struct vm_area_struct *vma, unsigned long addr,
257 policy->l_extent.start = ((addr - vma->vm_start) & PAGE_CACHE_MASK) +
258 (vma->vm_pgoff << PAGE_CACHE_SHIFT);
259 policy->l_extent.end = (policy->l_extent.start + count - 1) |
260 (PAGE_CACHE_SIZE - 1);
262 static struct vm_area_struct * our_vma(unsigned long addr, size_t count)
264 struct mm_struct *mm = current->mm;
265 struct vm_area_struct *vma, *ret = NULL;
268 spin_lock(&mm->page_table_lock);
269 for(vma = find_vma(mm, addr);
270 vma != NULL && vma->vm_start < (addr + count); vma = vma->vm_next) {
271 if (vma->vm_ops && vma->vm_ops->nopage == ll_nopage) {
276 spin_unlock(&mm->page_table_lock);
280 int lt_get_mmap_locks(struct ll_lock_tree *tree, struct inode *inode,
281 unsigned long addr, size_t count)
283 struct vm_area_struct *vma;
284 struct ll_lock_tree_node *node;
285 ldlm_policy_data_t policy;
291 /* we need to look up vmas on page aligned addresses */
292 count += addr & (PAGE_SIZE - 1);
293 addr -= addr & (PAGE_SIZE - 1);
295 while ((vma = our_vma(addr, count)) != NULL) {
297 policy_from_vma(&policy, vma, addr, count);
298 node = ll_node_from_inode(inode, policy.l_extent.start,
302 CERROR("not enough mem for lock_tree_node!\n");
305 lt_insert(tree, node);
307 if (vma->vm_end - addr >= count)
309 count -= vma->vm_end - addr;
314 /* FIXME: there is a pagefault race goes as follow:
315 * 1. A user process on node A accesses a portion of a mapped file,
316 * resulting in a page fault. The pagefault handler invokes the
317 * ll_nopage function, which reads the page into memory.
318 * 2. A user process on node B writes to the same portion of the file
319 * (either via mmap or write()), that cause node A to cancel the
320 * lock and truncate the page.
321 * 3. Node A then executes the rest of do_no_page(), entering the
322 * now-invalid page into the PTEs.
324 * Make the whole do_no_page as a hook to cover both the page cache
325 * and page mapping installing with dlm lock would eliminate this race.
327 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0))
328 struct page *ll_nopage(struct vm_area_struct *vma, unsigned long address,
331 struct page *ll_nopage(struct vm_area_struct *vma, unsigned long address,
335 struct file *filp = vma->vm_file;
336 struct ll_file_data *fd = filp->private_data;
337 struct inode *inode = filp->f_dentry->d_inode;
338 struct lustre_handle lockh = { 0 };
339 ldlm_policy_data_t policy;
342 struct obd_service_time *stime;
344 unsigned long pgoff, size, rand_read, seq_read;
348 if (ll_i2info(inode)->lli_smd == NULL) {
349 CERROR("No lsm on fault?\n");
353 /* start and end the lock on the first and last bytes in the page */
354 policy_from_vma(&policy, vma, address, PAGE_CACHE_SIZE);
356 CDEBUG(D_MMAP, "nopage vma %p inode %lu, locking ["LPU64", "LPU64"]\n",
357 vma, inode->i_ino, policy.l_extent.start,
358 policy.l_extent.end);
360 mode = mode_from_vma(vma);
361 stime = (mode & LCK_PW) ? &ll_i2sbi(inode)->ll_write_stime :
362 &ll_i2sbi(inode)->ll_read_stime;
364 rc = ll_extent_lock(fd, inode, ll_i2info(inode)->lli_smd, mode, &policy,
365 &lockh, LDLM_FL_CBPENDING, stime);
369 /* XXX change inode size without i_sem hold! there is a race condition
370 * with truncate path. (see ll_extent_lock) */
371 kms = lov_merge_size(ll_i2info(inode)->lli_smd, 1);
372 pgoff = ((address - vma->vm_start) >> PAGE_CACHE_SHIFT) + vma->vm_pgoff;
373 size = (kms + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
376 ll_glimpse_size(inode);
380 /* disable VM_SEQ_READ and use VM_RAND_READ to make sure that
381 * the kernel will not read other pages not covered by ldlm in
382 * filemap_nopage. we do our readahead in ll_readpage.
384 rand_read = vma->vm_flags & VM_RAND_READ;
385 seq_read = vma->vm_flags & VM_SEQ_READ;
386 vma->vm_flags &= ~ VM_SEQ_READ;
387 vma->vm_flags |= VM_RAND_READ;
389 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0))
390 page = filemap_nopage(vma, address, type);
392 page = filemap_nopage(vma, address, unused);
394 vma->vm_flags &= ~VM_RAND_READ;
395 vma->vm_flags |= (rand_read | seq_read);
397 ll_extent_unlock(fd, inode, ll_i2info(inode)->lli_smd, mode, &lockh);
401 /* return the user space pointer that maps to a file offset via a vma */
402 static inline unsigned long file_to_user(struct vm_area_struct *vma,
405 return vma->vm_start +
406 (byte - ((__u64)vma->vm_pgoff << PAGE_CACHE_SHIFT));
410 #define VMA_DEBUG(vma, fmt, arg...) \
411 CDEBUG(D_MMAP, "vma(%p) start(%ld) end(%ld) pgoff(%ld) inode(%p): " \
412 fmt, vma, vma->vm_start, vma->vm_end, vma->vm_pgoff, \
413 vma->vm_file->f_dentry->d_inode, ## arg);
415 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
416 /* [first, last] are the byte offsets affected.
417 * vm_{start, end} are user addresses of the first byte of the mapping and
418 * the next byte beyond it
419 * vm_pgoff is the page index of the first byte in the mapping */
420 static void teardown_vmas(struct vm_area_struct *vma, __u64 first,
423 unsigned long address, len;
424 for (; vma ; vma = vma->vm_next_share) {
425 if (last >> PAGE_CACHE_SHIFT < vma->vm_pgoff)
427 if (first >> PAGE_CACHE_SHIFT > (vma->vm_pgoff +
428 ((vma->vm_end - vma->vm_start) >> PAGE_CACHE_SHIFT)))
431 address = max((unsigned long)vma->vm_start,
432 file_to_user(vma, first));
433 len = min((unsigned long)vma->vm_end,
434 file_to_user(vma, last) + 1) - address;
436 VMA_DEBUG(vma, "zapping vma [address=%ld len=%ld]\n",
439 ll_zap_page_range(vma, address, len);
444 /* XXX put nice comment here. talk about __free_pte -> dirty pages and
445 * nopage's reference passing to the pte */
446 int ll_teardown_mmaps(struct address_space *mapping, __u64 first,
452 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0))
453 if (mapping_mapped(mapping)) {
455 unmap_mapping_range(mapping, first + PAGE_SIZE - 1,
456 last - first + 1, 1);
459 spin_lock(&mapping->i_shared_lock);
460 if (mapping->i_mmap != NULL) {
462 teardown_vmas(mapping->i_mmap, first, last);
464 if (mapping->i_mmap_shared != NULL) {
466 teardown_vmas(mapping->i_mmap_shared, first, last);
468 spin_unlock(&mapping->i_shared_lock);
474 static struct vm_operations_struct ll_file_vm_ops = {
478 int ll_file_mmap(struct file * file, struct vm_area_struct * vma)
483 rc = generic_file_mmap(file, vma);
485 vma->vm_ops = &ll_file_vm_ops;