2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/pagemap.h>
16 #include <linux/pagevec.h>
17 #include <linux/mpage.h>
19 #include <linux/writeback.h>
20 #include <linux/swap.h>
21 #include <linux/gfs2_ondisk.h>
22 #include <linux/backing-dev.h>
23 #include <linux/aio.h>
40 static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
41 unsigned int from, unsigned int to)
43 struct buffer_head *head = page_buffers(page);
44 unsigned int bsize = head->b_size;
45 struct buffer_head *bh;
46 unsigned int start, end;
48 for (bh = head, start = 0; bh != head || !start;
49 bh = bh->b_this_page, start = end) {
51 if (end <= from || start >= to)
53 if (gfs2_is_jdata(ip))
54 set_buffer_uptodate(bh);
55 gfs2_trans_add_data(ip->i_gl, bh);
60 * gfs2_get_block_noalloc - Fills in a buffer head with details about a block
62 * @lblock: The block number to look up
63 * @bh_result: The buffer head to return the result in
64 * @create: Non-zero if we may add block to the file
69 static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
70 struct buffer_head *bh_result, int create)
74 error = gfs2_block_map(inode, lblock, bh_result, 0);
77 if (!buffer_mapped(bh_result))
82 static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
83 struct buffer_head *bh_result, int create)
85 return gfs2_block_map(inode, lblock, bh_result, 0);
89 * gfs2_writepage_common - Common bits of writepage
90 * @page: The page to be written
91 * @wbc: The writeback control
93 * Returns: 1 if writepage is ok, otherwise an error code or zero if no error.
96 static int gfs2_writepage_common(struct page *page,
97 struct writeback_control *wbc)
99 struct inode *inode = page->mapping->host;
100 struct gfs2_inode *ip = GFS2_I(inode);
101 struct gfs2_sbd *sdp = GFS2_SB(inode);
102 loff_t i_size = i_size_read(inode);
103 pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
106 if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
108 if (current->journal_info)
110 /* Is the page fully outside i_size? (truncate in progress) */
111 offset = i_size & (PAGE_CACHE_SIZE-1);
112 if (page->index > end_index || (page->index == end_index && !offset)) {
113 page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
118 redirty_page_for_writepage(wbc, page);
125 * gfs2_writepage - Write page for writeback mappings
127 * @wbc: The writeback control
131 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
135 ret = gfs2_writepage_common(page, wbc);
139 return nobh_writepage(page, gfs2_get_block_noalloc, wbc);
143 * __gfs2_jdata_writepage - The core of jdata writepage
144 * @page: The page to write
145 * @wbc: The writeback control
147 * This is shared between writepage and writepages and implements the
148 * core of the writepage operation. If a transaction is required then
149 * PageChecked will have been set and the transaction will have
150 * already been started before this is called.
153 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
155 struct inode *inode = page->mapping->host;
156 struct gfs2_inode *ip = GFS2_I(inode);
157 struct gfs2_sbd *sdp = GFS2_SB(inode);
159 if (PageChecked(page)) {
160 ClearPageChecked(page);
161 if (!page_has_buffers(page)) {
162 create_empty_buffers(page, inode->i_sb->s_blocksize,
163 (1 << BH_Dirty)|(1 << BH_Uptodate));
165 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
167 return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
171 * gfs2_jdata_writepage - Write complete page
172 * @page: Page to write
178 static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
180 struct inode *inode = page->mapping->host;
181 struct gfs2_sbd *sdp = GFS2_SB(inode);
185 if (PageChecked(page)) {
186 if (wbc->sync_mode != WB_SYNC_ALL)
188 ret = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
193 ret = gfs2_writepage_common(page, wbc);
195 ret = __gfs2_jdata_writepage(page, wbc);
201 redirty_page_for_writepage(wbc, page);
207 * gfs2_writepages - Write a bunch of dirty pages back to disk
208 * @mapping: The mapping to write
209 * @wbc: Write-back control
211 * Used for both ordered and writeback modes.
213 static int gfs2_writepages(struct address_space *mapping,
214 struct writeback_control *wbc)
216 return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
220 * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
221 * @mapping: The mapping
222 * @wbc: The writeback control
223 * @writepage: The writepage function to call for each page
224 * @pvec: The vector of pages
225 * @nr_pages: The number of pages to write
227 * Returns: non-zero if loop should terminate, zero otherwise
230 static int gfs2_write_jdata_pagevec(struct address_space *mapping,
231 struct writeback_control *wbc,
232 struct pagevec *pvec,
233 int nr_pages, pgoff_t end)
235 struct inode *inode = mapping->host;
236 struct gfs2_sbd *sdp = GFS2_SB(inode);
237 loff_t i_size = i_size_read(inode);
238 pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
239 unsigned offset = i_size & (PAGE_CACHE_SIZE-1);
240 unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize);
244 ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
248 for(i = 0; i < nr_pages; i++) {
249 struct page *page = pvec->pages[i];
253 if (unlikely(page->mapping != mapping)) {
258 if (!wbc->range_cyclic && page->index > end) {
264 if (wbc->sync_mode != WB_SYNC_NONE)
265 wait_on_page_writeback(page);
267 if (PageWriteback(page) ||
268 !clear_page_dirty_for_io(page)) {
273 /* Is the page fully outside i_size? (truncate in progress) */
274 if (page->index > end_index || (page->index == end_index && !offset)) {
275 page->mapping->a_ops->invalidatepage(page, 0,
281 ret = __gfs2_jdata_writepage(page, wbc);
283 if (ret || (--(wbc->nr_to_write) <= 0))
291 * gfs2_write_cache_jdata - Like write_cache_pages but different
292 * @mapping: The mapping to write
293 * @wbc: The writeback control
294 * @writepage: The writepage function to call
295 * @data: The data to pass to writepage
297 * The reason that we use our own function here is that we need to
298 * start transactions before we grab page locks. This allows us
299 * to get the ordering right.
302 static int gfs2_write_cache_jdata(struct address_space *mapping,
303 struct writeback_control *wbc)
314 pagevec_init(&pvec, 0);
315 if (wbc->range_cyclic) {
316 index = mapping->writeback_index; /* Start from prev offset */
319 index = wbc->range_start >> PAGE_CACHE_SHIFT;
320 end = wbc->range_end >> PAGE_CACHE_SHIFT;
321 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
327 while (!done && (index <= end) &&
328 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
330 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
332 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end);
338 pagevec_release(&pvec);
342 if (!scanned && !done) {
344 * We hit the last page and there is more work to be done: wrap
345 * back to the start of the file
352 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
353 mapping->writeback_index = index;
359 * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
360 * @mapping: The mapping to write
361 * @wbc: The writeback control
365 static int gfs2_jdata_writepages(struct address_space *mapping,
366 struct writeback_control *wbc)
368 struct gfs2_inode *ip = GFS2_I(mapping->host);
369 struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
372 ret = gfs2_write_cache_jdata(mapping, wbc);
373 if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
374 gfs2_log_flush(sdp, ip->i_gl);
375 ret = gfs2_write_cache_jdata(mapping, wbc);
381 * stuffed_readpage - Fill in a Linux page with stuffed file data
388 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
390 struct buffer_head *dibh;
391 u64 dsize = i_size_read(&ip->i_inode);
396 * Due to the order of unstuffing files and ->fault(), we can be
397 * asked for a zero page in the case of a stuffed file being extended,
398 * so we need to supply one here. It doesn't happen often.
400 if (unlikely(page->index)) {
401 zero_user(page, 0, PAGE_CACHE_SIZE);
402 SetPageUptodate(page);
406 error = gfs2_meta_inode_buffer(ip, &dibh);
410 kaddr = kmap_atomic(page);
411 if (dsize > (dibh->b_size - sizeof(struct gfs2_dinode)))
412 dsize = (dibh->b_size - sizeof(struct gfs2_dinode));
413 memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
414 memset(kaddr + dsize, 0, PAGE_CACHE_SIZE - dsize);
415 kunmap_atomic(kaddr);
416 flush_dcache_page(page);
418 SetPageUptodate(page);
425 * __gfs2_readpage - readpage
426 * @file: The file to read a page for
427 * @page: The page to read
429 * This is the core of gfs2's readpage. Its used by the internal file
430 * reading code as in that case we already hold the glock. Also its
431 * called by gfs2_readpage() once the required lock has been granted.
435 static int __gfs2_readpage(void *file, struct page *page)
437 struct gfs2_inode *ip = GFS2_I(page->mapping->host);
438 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
441 if (gfs2_is_stuffed(ip)) {
442 error = stuffed_readpage(ip, page);
445 error = mpage_readpage(page, gfs2_block_map);
448 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
455 * gfs2_readpage - read a page of a file
456 * @file: The file to read
457 * @page: The page of the file
459 * This deals with the locking required. We have to unlock and
460 * relock the page in order to get the locking in the right
464 static int gfs2_readpage(struct file *file, struct page *page)
466 struct address_space *mapping = page->mapping;
467 struct gfs2_inode *ip = GFS2_I(mapping->host);
468 struct gfs2_holder gh;
472 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
473 error = gfs2_glock_nq(&gh);
476 error = AOP_TRUNCATED_PAGE;
478 if (page->mapping == mapping && !PageUptodate(page))
479 error = __gfs2_readpage(file, page);
484 gfs2_holder_uninit(&gh);
485 if (error && error != AOP_TRUNCATED_PAGE)
491 * gfs2_internal_read - read an internal file
492 * @ip: The gfs2 inode
493 * @buf: The buffer to fill
494 * @pos: The file position
495 * @size: The amount to read
499 int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
502 struct address_space *mapping = ip->i_inode.i_mapping;
503 unsigned long index = *pos / PAGE_CACHE_SIZE;
504 unsigned offset = *pos & (PAGE_CACHE_SIZE - 1);
512 if (offset + size > PAGE_CACHE_SIZE)
513 amt = PAGE_CACHE_SIZE - offset;
514 page = read_cache_page(mapping, index, __gfs2_readpage, NULL);
516 return PTR_ERR(page);
517 p = kmap_atomic(page);
518 memcpy(buf + copied, p + offset, amt);
520 mark_page_accessed(page);
521 page_cache_release(page);
525 } while(copied < size);
531 * gfs2_readpages - Read a bunch of pages at once
534 * 1. This is only for readahead, so we can simply ignore any things
535 * which are slightly inconvenient (such as locking conflicts between
536 * the page lock and the glock) and return having done no I/O. Its
537 * obviously not something we'd want to do on too regular a basis.
538 * Any I/O we ignore at this time will be done via readpage later.
539 * 2. We don't handle stuffed files here we let readpage do the honours.
540 * 3. mpage_readpages() does most of the heavy lifting in the common case.
541 * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
544 static int gfs2_readpages(struct file *file, struct address_space *mapping,
545 struct list_head *pages, unsigned nr_pages)
547 struct inode *inode = mapping->host;
548 struct gfs2_inode *ip = GFS2_I(inode);
549 struct gfs2_sbd *sdp = GFS2_SB(inode);
550 struct gfs2_holder gh;
553 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
554 ret = gfs2_glock_nq(&gh);
557 if (!gfs2_is_stuffed(ip))
558 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
561 gfs2_holder_uninit(&gh);
562 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
568 * gfs2_write_begin - Begin to write to a file
569 * @file: The file to write to
570 * @mapping: The mapping in which to write
571 * @pos: The file offset at which to start writing
572 * @len: Length of the write
573 * @flags: Various flags
574 * @pagep: Pointer to return the page
575 * @fsdata: Pointer to return fs data (unused by GFS2)
580 static int gfs2_write_begin(struct file *file, struct address_space *mapping,
581 loff_t pos, unsigned len, unsigned flags,
582 struct page **pagep, void **fsdata)
584 struct gfs2_inode *ip = GFS2_I(mapping->host);
585 struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
586 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
587 unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
588 unsigned requested = 0;
591 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
592 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
595 gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
596 error = gfs2_glock_nq(&ip->i_gh);
599 if (&ip->i_inode == sdp->sd_rindex) {
600 error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE,
601 GL_NOCACHE, &m_ip->i_gh);
602 if (unlikely(error)) {
603 gfs2_glock_dq(&ip->i_gh);
608 alloc_required = gfs2_write_alloc_required(ip, pos, len);
610 if (alloc_required || gfs2_is_jdata(ip))
611 gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
613 if (alloc_required) {
614 error = gfs2_quota_lock_check(ip);
618 requested = data_blocks + ind_blocks;
619 error = gfs2_inplace_reserve(ip, requested, 0);
624 rblocks = RES_DINODE + ind_blocks;
625 if (gfs2_is_jdata(ip))
626 rblocks += data_blocks ? data_blocks : 1;
627 if (ind_blocks || data_blocks)
628 rblocks += RES_STATFS + RES_QUOTA;
629 if (&ip->i_inode == sdp->sd_rindex)
630 rblocks += 2 * RES_STATFS;
632 rblocks += gfs2_rg_blocks(ip, requested);
634 error = gfs2_trans_begin(sdp, rblocks,
635 PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
640 flags |= AOP_FLAG_NOFS;
641 page = grab_cache_page_write_begin(mapping, index, flags);
646 if (gfs2_is_stuffed(ip)) {
648 if (pos + len > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
649 error = gfs2_unstuff_dinode(ip, page);
652 } else if (!PageUptodate(page)) {
653 error = stuffed_readpage(ip, page);
659 error = __block_write_begin(page, from, len, gfs2_block_map);
665 page_cache_release(page);
668 if (pos + len > ip->i_inode.i_size)
669 gfs2_trim_blocks(&ip->i_inode);
675 if (alloc_required) {
676 gfs2_inplace_release(ip);
678 gfs2_quota_unlock(ip);
681 if (&ip->i_inode == sdp->sd_rindex) {
682 gfs2_glock_dq(&m_ip->i_gh);
683 gfs2_holder_uninit(&m_ip->i_gh);
685 gfs2_glock_dq(&ip->i_gh);
687 gfs2_holder_uninit(&ip->i_gh);
692 * adjust_fs_space - Adjusts the free space available due to gfs2_grow
693 * @inode: the rindex inode
695 static void adjust_fs_space(struct inode *inode)
697 struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
698 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
699 struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
700 struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
701 struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
702 struct buffer_head *m_bh, *l_bh;
703 u64 fs_total, new_free;
705 /* Total up the file system space, according to the latest rindex. */
706 fs_total = gfs2_ri_total(sdp);
707 if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0)
710 spin_lock(&sdp->sd_statfs_spin);
711 gfs2_statfs_change_in(m_sc, m_bh->b_data +
712 sizeof(struct gfs2_dinode));
713 if (fs_total > (m_sc->sc_total + l_sc->sc_total))
714 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
717 spin_unlock(&sdp->sd_statfs_spin);
718 fs_warn(sdp, "File system extended by %llu blocks.\n",
719 (unsigned long long)new_free);
720 gfs2_statfs_change(sdp, new_free, new_free, 0);
722 if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0)
724 update_statfs(sdp, m_bh, l_bh);
731 * gfs2_stuffed_write_end - Write end for stuffed files
733 * @dibh: The buffer_head containing the on-disk inode
734 * @pos: The file position
735 * @len: The length of the write
736 * @copied: How much was actually copied by the VFS
739 * This copies the data from the page into the inode block after
740 * the inode data structure itself.
744 static int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh,
745 loff_t pos, unsigned len, unsigned copied,
748 struct gfs2_inode *ip = GFS2_I(inode);
749 struct gfs2_sbd *sdp = GFS2_SB(inode);
750 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
751 u64 to = pos + copied;
753 unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode);
755 BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode)));
756 kaddr = kmap_atomic(page);
757 memcpy(buf + pos, kaddr + pos, copied);
758 memset(kaddr + pos + copied, 0, len - copied);
759 flush_dcache_page(page);
760 kunmap_atomic(kaddr);
762 if (!PageUptodate(page))
763 SetPageUptodate(page);
765 page_cache_release(page);
768 if (inode->i_size < to)
769 i_size_write(inode, to);
770 mark_inode_dirty(inode);
773 if (inode == sdp->sd_rindex) {
774 adjust_fs_space(inode);
775 sdp->sd_rindex_uptodate = 0;
780 if (inode == sdp->sd_rindex) {
781 gfs2_glock_dq(&m_ip->i_gh);
782 gfs2_holder_uninit(&m_ip->i_gh);
784 gfs2_glock_dq(&ip->i_gh);
785 gfs2_holder_uninit(&ip->i_gh);
791 * @file: The file to write to
792 * @mapping: The address space to write to
793 * @pos: The file position
794 * @len: The length of the data
796 * @page: The page that has been written
797 * @fsdata: The fsdata (unused in GFS2)
799 * The main write_end function for GFS2. We have a separate one for
800 * stuffed files as they are slightly different, otherwise we just
801 * put our locking around the VFS provided functions.
806 static int gfs2_write_end(struct file *file, struct address_space *mapping,
807 loff_t pos, unsigned len, unsigned copied,
808 struct page *page, void *fsdata)
810 struct inode *inode = page->mapping->host;
811 struct gfs2_inode *ip = GFS2_I(inode);
812 struct gfs2_sbd *sdp = GFS2_SB(inode);
813 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
814 struct buffer_head *dibh;
815 unsigned int from = pos & (PAGE_CACHE_SIZE - 1);
816 unsigned int to = from + len;
819 BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL);
821 ret = gfs2_meta_inode_buffer(ip, &dibh);
824 page_cache_release(page);
828 gfs2_trans_add_meta(ip->i_gl, dibh);
830 if (gfs2_is_stuffed(ip))
831 return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page);
833 if (!gfs2_is_writeback(ip))
834 gfs2_page_add_databufs(ip, page, from, to);
836 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
838 if (inode == sdp->sd_rindex) {
839 adjust_fs_space(inode);
840 sdp->sd_rindex_uptodate = 0;
846 gfs2_inplace_release(ip);
847 if (ip->i_res->rs_qa_qd_num)
848 gfs2_quota_unlock(ip);
849 if (inode == sdp->sd_rindex) {
850 gfs2_glock_dq(&m_ip->i_gh);
851 gfs2_holder_uninit(&m_ip->i_gh);
853 gfs2_glock_dq(&ip->i_gh);
854 gfs2_holder_uninit(&ip->i_gh);
859 * gfs2_set_page_dirty - Page dirtying function
860 * @page: The page to dirty
862 * Returns: 1 if it dirtyed the page, or 0 otherwise
865 static int gfs2_set_page_dirty(struct page *page)
867 SetPageChecked(page);
868 return __set_page_dirty_buffers(page);
872 * gfs2_bmap - Block map function
873 * @mapping: Address space info
874 * @lblock: The block to map
876 * Returns: The disk address for the block or 0 on hole or error
879 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
881 struct gfs2_inode *ip = GFS2_I(mapping->host);
882 struct gfs2_holder i_gh;
886 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
890 if (!gfs2_is_stuffed(ip))
891 dblock = generic_block_bmap(mapping, lblock, gfs2_block_map);
893 gfs2_glock_dq_uninit(&i_gh);
898 static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
900 struct gfs2_bufdata *bd;
904 clear_buffer_dirty(bh);
907 if (!list_empty(&bd->bd_list) && !buffer_pinned(bh))
908 list_del_init(&bd->bd_list);
910 gfs2_remove_from_journal(bh, current->journal_info, 0);
913 clear_buffer_mapped(bh);
914 clear_buffer_req(bh);
915 clear_buffer_new(bh);
916 gfs2_log_unlock(sdp);
920 static void gfs2_invalidatepage(struct page *page, unsigned int offset,
923 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
924 unsigned int stop = offset + length;
925 int partial_page = (offset || length < PAGE_CACHE_SIZE);
926 struct buffer_head *bh, *head;
927 unsigned long pos = 0;
929 BUG_ON(!PageLocked(page));
931 ClearPageChecked(page);
932 if (!page_has_buffers(page))
935 bh = head = page_buffers(page);
937 if (pos + bh->b_size > stop)
941 gfs2_discard(sdp, bh);
943 bh = bh->b_this_page;
944 } while (bh != head);
947 try_to_release_page(page, 0);
951 * gfs2_ok_for_dio - check that dio is valid on this file
954 * @offset: The offset at which we are reading or writing
956 * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
957 * 1 (to accept the i/o request)
959 static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
962 * Should we return an error here? I can't see that O_DIRECT for
963 * a stuffed file makes any sense. For now we'll silently fall
964 * back to buffered I/O
966 if (gfs2_is_stuffed(ip))
969 if (offset >= i_size_read(&ip->i_inode))
976 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
977 const struct iovec *iov, loff_t offset,
978 unsigned long nr_segs)
980 struct file *file = iocb->ki_filp;
981 struct inode *inode = file->f_mapping->host;
982 struct gfs2_inode *ip = GFS2_I(inode);
983 struct gfs2_holder gh;
987 * Deferred lock, even if its a write, since we do no allocation
988 * on this path. All we need change is atime, and this lock mode
989 * ensures that other nodes have flushed their buffered read caches
990 * (i.e. their page cache entries for this inode). We do not,
991 * unfortunately have the option of only flushing a range like
994 gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
995 rv = gfs2_glock_nq(&gh);
998 rv = gfs2_ok_for_dio(ip, rw, offset);
1000 goto out; /* dio not valid, fall back to buffered i/o */
1002 rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
1003 offset, nr_segs, gfs2_get_block_direct,
1007 gfs2_holder_uninit(&gh);
1012 * gfs2_releasepage - free the metadata associated with a page
1013 * @page: the page that's being released
1014 * @gfp_mask: passed from Linux VFS, ignored by us
1016 * Call try_to_free_buffers() if the buffers in this page can be
1022 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
1024 struct address_space *mapping = page->mapping;
1025 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
1026 struct buffer_head *bh, *head;
1027 struct gfs2_bufdata *bd;
1029 if (!page_has_buffers(page))
1033 spin_lock(&sdp->sd_ail_lock);
1034 head = bh = page_buffers(page);
1036 if (atomic_read(&bh->b_count))
1037 goto cannot_release;
1039 if (bd && bd->bd_tr)
1040 goto cannot_release;
1041 if (buffer_pinned(bh) || buffer_dirty(bh))
1043 bh = bh->b_this_page;
1044 } while(bh != head);
1045 spin_unlock(&sdp->sd_ail_lock);
1046 gfs2_log_unlock(sdp);
1048 head = bh = page_buffers(page);
1053 gfs2_assert_warn(sdp, bd->bd_bh == bh);
1054 if (!list_empty(&bd->bd_list)) {
1055 if (!buffer_pinned(bh))
1056 list_del_init(&bd->bd_list);
1062 bh->b_private = NULL;
1064 gfs2_log_unlock(sdp);
1066 kmem_cache_free(gfs2_bufdata_cachep, bd);
1068 bh = bh->b_this_page;
1069 } while (bh != head);
1071 return try_to_free_buffers(page);
1073 not_possible: /* Should never happen */
1074 WARN_ON(buffer_dirty(bh));
1075 WARN_ON(buffer_pinned(bh));
1077 spin_unlock(&sdp->sd_ail_lock);
1078 gfs2_log_unlock(sdp);
1082 static const struct address_space_operations gfs2_writeback_aops = {
1083 .writepage = gfs2_writepage,
1084 .writepages = gfs2_writepages,
1085 .readpage = gfs2_readpage,
1086 .readpages = gfs2_readpages,
1087 .write_begin = gfs2_write_begin,
1088 .write_end = gfs2_write_end,
1090 .invalidatepage = gfs2_invalidatepage,
1091 .releasepage = gfs2_releasepage,
1092 .direct_IO = gfs2_direct_IO,
1093 .migratepage = buffer_migrate_page,
1094 .is_partially_uptodate = block_is_partially_uptodate,
1095 .error_remove_page = generic_error_remove_page,
1098 static const struct address_space_operations gfs2_ordered_aops = {
1099 .writepage = gfs2_writepage,
1100 .writepages = gfs2_writepages,
1101 .readpage = gfs2_readpage,
1102 .readpages = gfs2_readpages,
1103 .write_begin = gfs2_write_begin,
1104 .write_end = gfs2_write_end,
1105 .set_page_dirty = gfs2_set_page_dirty,
1107 .invalidatepage = gfs2_invalidatepage,
1108 .releasepage = gfs2_releasepage,
1109 .direct_IO = gfs2_direct_IO,
1110 .migratepage = buffer_migrate_page,
1111 .is_partially_uptodate = block_is_partially_uptodate,
1112 .error_remove_page = generic_error_remove_page,
1115 static const struct address_space_operations gfs2_jdata_aops = {
1116 .writepage = gfs2_jdata_writepage,
1117 .writepages = gfs2_jdata_writepages,
1118 .readpage = gfs2_readpage,
1119 .readpages = gfs2_readpages,
1120 .write_begin = gfs2_write_begin,
1121 .write_end = gfs2_write_end,
1122 .set_page_dirty = gfs2_set_page_dirty,
1124 .invalidatepage = gfs2_invalidatepage,
1125 .releasepage = gfs2_releasepage,
1126 .is_partially_uptodate = block_is_partially_uptodate,
1127 .error_remove_page = generic_error_remove_page,
1130 void gfs2_set_aops(struct inode *inode)
1132 struct gfs2_inode *ip = GFS2_I(inode);
1134 if (gfs2_is_writeback(ip))
1135 inode->i_mapping->a_ops = &gfs2_writeback_aops;
1136 else if (gfs2_is_ordered(ip))
1137 inode->i_mapping->a_ops = &gfs2_ordered_aops;
1138 else if (gfs2_is_jdata(ip))
1139 inode->i_mapping->a_ops = &gfs2_jdata_aops;