/* * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This copyrighted material is made available to anyone wishing to use, * modify, copy, or redistribute it subject to the terms and conditions * of the GNU General Public License version 2. */ #include <linux/sched.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/completion.h> #include <linux/buffer_head.h> #include <linux/pagemap.h> #include <linux/pagevec.h> #include <linux/mpage.h> #include <linux/fs.h> #include <linux/writeback.h> #include <linux/swap.h> #include <linux/gfs2_ondisk.h> #include <linux/backing-dev.h> #include <linux/uio.h> #include <trace/events/writeback.h> #include "gfs2.h" #include "incore.h" #include "bmap.h" #include "glock.h" #include "inode.h" #include "log.h" #include "meta_io.h" #include "quota.h" #include "trans.h" #include "rgrp.h" #include "super.h" #include "util.h" #include "glops.h" static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page, unsigned int from, unsigned int to) { struct buffer_head *head = page_buffers(page); unsigned int bsize = head->b_size; struct buffer_head *bh; unsigned int start, end; for (bh = head, start = 0; bh != head || !start; bh = bh->b_this_page, start = end) { end = start + bsize; if (end <= from || start >= to) continue; if (gfs2_is_jdata(ip)) set_buffer_uptodate(bh); gfs2_trans_add_data(ip->i_gl, bh); } } /** * gfs2_get_block_noalloc - Fills in a buffer head with details about a block * @inode: The inode * @lblock: The block number to look up * @bh_result: The buffer head to return the result in * @create: Non-zero if we may add block to the file * * Returns: errno */ static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock, struct buffer_head *bh_result, int create) { int error; error = gfs2_block_map(inode, lblock, bh_result, 0); if (error) return error; if (!buffer_mapped(bh_result)) return -EIO; return 0; } static int gfs2_get_block_direct(struct inode *inode, sector_t lblock, struct buffer_head *bh_result, int create) { return gfs2_block_map(inode, lblock, bh_result, 0); } /** * gfs2_writepage_common - Common bits of writepage * @page: The page to be written * @wbc: The writeback control * * Returns: 1 if writepage is ok, otherwise an error code or zero if no error. */ static int gfs2_writepage_common(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_sbd *sdp = GFS2_SB(inode); loff_t i_size = i_size_read(inode); pgoff_t end_index = i_size >> PAGE_SHIFT; unsigned offset; if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) goto out; if (current->journal_info) goto redirty; /* Is the page fully outside i_size? (truncate in progress) */ offset = i_size & (PAGE_SIZE-1); if (page->index > end_index || (page->index == end_index && !offset)) { page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE); goto out; } return 1; redirty: redirty_page_for_writepage(wbc, page); out: unlock_page(page); return 0; } /** * gfs2_writepage - Write page for writeback mappings * @page: The page * @wbc: The writeback control * */ static int gfs2_writepage(struct page *page, struct writeback_control *wbc) { int ret; ret = gfs2_writepage_common(page, wbc); if (ret <= 0) return ret; return nobh_writepage(page, gfs2_get_block_noalloc, wbc); } /* This is the same as calling block_write_full_page, but it also * writes pages outside of i_size */ int gfs2_write_full_page(struct page *page, get_block_t *get_block, struct writeback_control *wbc) { struct inode * const inode = page->mapping->host; loff_t i_size = i_size_read(inode); const pgoff_t end_index = i_size >> PAGE_SHIFT; unsigned offset; /* * The page straddles i_size. It must be zeroed out on each and every * writepage invocation because it may be mmapped. "A file is mapped * in multiples of the page size. For a file that is not a multiple of * the page size, the remaining memory is zeroed when mapped, and * writes to that region are not written out to the file." */ offset = i_size & (PAGE_SIZE-1); if (page->index == end_index && offset) zero_user_segment(page, offset, PAGE_SIZE); return __block_write_full_page(inode, page, get_block, wbc, end_buffer_async_write); } /** * __gfs2_jdata_writepage - The core of jdata writepage * @page: The page to write * @wbc: The writeback control * * This is shared between writepage and writepages and implements the * core of the writepage operation. If a transaction is required then * PageChecked will have been set and the transaction will have * already been started before this is called. */ static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_sbd *sdp = GFS2_SB(inode); if (PageChecked(page)) { ClearPageChecked(page); if (!page_has_buffers(page)) { create_empty_buffers(page, inode->i_sb->s_blocksize, BIT(BH_Dirty)|BIT(BH_Uptodate)); } gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1); } return gfs2_write_full_page(page, gfs2_get_block_noalloc, wbc); } /** * gfs2_jdata_writepage - Write complete page * @page: Page to write * @wbc: The writeback control * * Returns: errno * */ static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_sbd *sdp = GFS2_SB(inode); int ret; if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) goto out; if (PageChecked(page) || current->journal_info) goto out_ignore; ret = __gfs2_jdata_writepage(page, wbc); return ret; out_ignore: redirty_page_for_writepage(wbc, page); out: unlock_page(page); return 0; } /** * gfs2_writepages - Write a bunch of dirty pages back to disk * @mapping: The mapping to write * @wbc: Write-back control * * Used for both ordered and writeback modes. */ static int gfs2_writepages(struct address_space *mapping, struct writeback_control *wbc) { return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc); } /** * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages * @mapping: The mapping * @wbc: The writeback control * @pvec: The vector of pages * @nr_pages: The number of pages to write * @end: End position * @done_index: Page index * * Returns: non-zero if loop should terminate, zero otherwise */ static int gfs2_write_jdata_pagevec(struct address_space *mapping, struct writeback_control *wbc, struct pagevec *pvec, int nr_pages, pgoff_t end, pgoff_t *done_index) { struct inode *inode = mapping->host; struct gfs2_sbd *sdp = GFS2_SB(inode); unsigned nrblocks = nr_pages * (PAGE_SIZE/inode->i_sb->s_blocksize); int i; int ret; ret = gfs2_trans_begin(sdp, nrblocks, nrblocks); if (ret < 0) return ret; for(i = 0; i < nr_pages; i++) { struct page *page = pvec->pages[i]; /* * At this point, the page may be truncated or * invalidated (changing page->mapping to NULL), or * even swizzled back from swapper_space to tmpfs file * mapping. However, page->index will not change * because we have a reference on the page. */ if (page->index > end) { /* * can't be range_cyclic (1st pass) because * end == -1 in that case. */ ret = 1; break; } *done_index = page->index; lock_page(page); if (unlikely(page->mapping != mapping)) { continue_unlock: unlock_page(page); continue; } if (!PageDirty(page)) { /* someone wrote it for us */ goto continue_unlock; } if (PageWriteback(page)) { if (wbc->sync_mode != WB_SYNC_NONE) wait_on_page_writeback(page); else goto continue_unlock; } BUG_ON(PageWriteback(page)); if (!clear_page_dirty_for_io(page)) goto continue_unlock; trace_wbc_writepage(wbc, inode_to_bdi(inode)); ret = __gfs2_jdata_writepage(page, wbc); if (unlikely(ret)) { if (ret == AOP_WRITEPAGE_ACTIVATE) { unlock_page(page); ret = 0; } else { /* * done_index is set past this page, * so media errors will not choke * background writeout for the entire * file. This has consequences for * range_cyclic semantics (ie. it may * not be suitable for data integrity * writeout). */ *done_index = page->index + 1; ret = 1; break; } } /* * We stop writing back only if we are not doing * integrity sync. In case of integrity sync we have to * keep going until we have written all the pages * we tagged for writeback prior to entering this loop. */ if (--wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) { ret = 1; break; } } gfs2_trans_end(sdp); return ret; } /** * gfs2_write_cache_jdata - Like write_cache_pages but different * @mapping: The mapping to write * @wbc: The writeback control * * The reason that we use our own function here is that we need to * start transactions before we grab page locks. This allows us * to get the ordering right. */ static int gfs2_write_cache_jdata(struct address_space *mapping, struct writeback_control *wbc) { int ret = 0; int done = 0; struct pagevec pvec; int nr_pages; pgoff_t uninitialized_var(writeback_index); pgoff_t index; pgoff_t end; pgoff_t done_index; int cycled; int range_whole = 0; int tag; pagevec_init(&pvec, 0); if (wbc->range_cyclic) { writeback_index = mapping->writeback_index; /* prev offset */ index = writeback_index; if (index == 0) cycled = 1; else cycled = 0; end = -1; } else { index = wbc->range_start >> PAGE_SHIFT; end = wbc->range_end >> PAGE_SHIFT; if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) range_whole = 1; cycled = 1; /* ignore range_cyclic tests */ } if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) tag = PAGECACHE_TAG_TOWRITE; else tag = PAGECACHE_TAG_DIRTY; retry: if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) tag_pages_for_writeback(mapping, index, end); done_index = index; while (!done && (index <= end)) { nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag, min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1); if (nr_pages == 0) break; ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end, &done_index); if (ret) done = 1; if (ret > 0) ret = 0; pagevec_release(&pvec); cond_resched(); } if (!cycled && !done) { /* * range_cyclic: * We hit the last page and there is more work to be done: wrap * back to the start of the file */ cycled = 1; index = 0; end = writeback_index - 1; goto retry; } if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) mapping->writeback_index = done_index; return ret; } /** * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk * @mapping: The mapping to write * @wbc: The writeback control * */ static int gfs2_jdata_writepages(struct address_space *mapping, struct writeback_control *wbc) { struct gfs2_inode *ip = GFS2_I(mapping->host); struct gfs2_sbd *sdp = GFS2_SB(mapping->host); int ret; ret = gfs2_write_cache_jdata(mapping, wbc); if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) { gfs2_log_flush(sdp, ip->i_gl, NORMAL_FLUSH); ret = gfs2_write_cache_jdata(mapping, wbc); } return ret; } /** * stuffed_readpage - Fill in a Linux page with stuffed file data * @ip: the inode * @page: the page * * Returns: errno */ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page) { struct buffer_head *dibh; u64 dsize = i_size_read(&ip->i_inode); void *kaddr; int error; /* * Due to the order of unstuffing files and ->fault(), we can be * asked for a zero page in the case of a stuffed file being extended, * so we need to supply one here. It doesn't happen often. */ if (unlikely(page->index)) { zero_user(page, 0, PAGE_SIZE); SetPageUptodate(page); return 0; } error = gfs2_meta_inode_buffer(ip, &dibh); if (error) return error; kaddr = kmap_atomic(page); if (dsize > (dibh->b_size - sizeof(struct gfs2_dinode))) dsize = (dibh->b_size - sizeof(struct gfs2_dinode)); memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize); memset(kaddr + dsize, 0, PAGE_SIZE - dsize); kunmap_atomic(kaddr); flush_dcache_page(page); brelse(dibh); SetPageUptodate(page); return 0; } /** * __gfs2_readpage - readpage * @file: The file to read a page for * @page: The page to read * * This is the core of gfs2's readpage. Its used by the internal file * reading code as in that case we already hold the glock. Also its * called by gfs2_readpage() once the required lock has been granted. * */ static int __gfs2_readpage(void *file, struct page *page) { struct gfs2_inode *ip = GFS2_I(page->mapping->host); struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host); int error; if (gfs2_is_stuffed(ip)) { error = stuffed_readpage(ip, page); unlock_page(page); } else { error = mpage_readpage(page, gfs2_block_map); } if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) return -EIO; return error; } /** * gfs2_readpage - read a page of a file * @file: The file to read * @page: The page of the file * * This deals with the locking required. We have to unlock and * relock the page in order to get the locking in the right * order. */ static int gfs2_readpage(struct file *file, struct page *page) { struct address_space *mapping = page->mapping; struct gfs2_inode *ip = GFS2_I(mapping->host); struct gfs2_holder gh; int error; unlock_page(page); gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh); error = gfs2_glock_nq(&gh); if (unlikely(error)) goto out; error = AOP_TRUNCATED_PAGE; lock_page(page); if (page->mapping == mapping && !PageUptodate(page)) error = __gfs2_readpage(file, page); else unlock_page(page); gfs2_glock_dq(&gh); out: gfs2_holder_uninit(&gh); if (error && error != AOP_TRUNCATED_PAGE) lock_page(page); return error; } /** * gfs2_internal_read - read an internal file * @ip: The gfs2 inode * @buf: The buffer to fill * @pos: The file position * @size: The amount to read * */ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos, unsigned size) { struct address_space *mapping = ip->i_inode.i_mapping; unsigned long index = *pos / PAGE_SIZE; unsigned offset = *pos & (PAGE_SIZE - 1); unsigned copied = 0; unsigned amt; struct page *page; void *p; do { amt = size - copied; if (offset + size > PAGE_SIZE) amt = PAGE_SIZE - offset; page = read_cache_page(mapping, index, __gfs2_readpage, NULL); if (IS_ERR(page)) return PTR_ERR(page); p = kmap_atomic(page); memcpy(buf + copied, p + offset, amt); kunmap_atomic(p); put_page(page); copied += amt; index++; offset = 0; } while(copied < size); (*pos) += size; return size; } /** * gfs2_readpages - Read a bunch of pages at once * @file: The file to read from * @mapping: Address space info * @pages: List of pages to read * @nr_pages: Number of pages to read * * Some notes: * 1. This is only for readahead, so we can simply ignore any things * which are slightly inconvenient (such as locking conflicts between * the page lock and the glock) and return having done no I/O. Its * obviously not something we'd want to do on too regular a basis. * Any I/O we ignore at this time will be done via readpage later. * 2. We don't handle stuffed files here we let readpage do the honours. * 3. mpage_readpages() does most of the heavy lifting in the common case. * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places. */ static int gfs2_readpages(struct file *file, struct address_space *mapping, struct list_head *pages, unsigned nr_pages) { struct inode *inode = mapping->host; struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_sbd *sdp = GFS2_SB(inode); struct gfs2_holder gh; int ret; gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh); ret = gfs2_glock_nq(&gh); if (unlikely(ret)) goto out_uninit; if (!gfs2_is_stuffed(ip)) ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map); gfs2_glock_dq(&gh); out_uninit: gfs2_holder_uninit(&gh); if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) ret = -EIO; return ret; } /** * gfs2_write_begin - Begin to write to a file * @file: The file to write to * @mapping: The mapping in which to write * @pos: The file offset at which to start writing * @len: Length of the write * @flags: Various flags * @pagep: Pointer to return the page * @fsdata: Pointer to return fs data (unused by GFS2) * * Returns: errno */ static int gfs2_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { struct gfs2_inode *ip = GFS2_I(mapping->host); struct gfs2_sbd *sdp = GFS2_SB(mapping->host); struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); unsigned int data_blocks = 0, ind_blocks = 0, rblocks; unsigned requested = 0; int alloc_required; int error = 0; pgoff_t index = pos >> PAGE_SHIFT; unsigned from = pos & (PAGE_SIZE - 1); struct page *page; gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh); error = gfs2_glock_nq(&ip->i_gh); if (unlikely(error)) goto out_uninit; if (&ip->i_inode == sdp->sd_rindex) { error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE, &m_ip->i_gh); if (unlikely(error)) { gfs2_glock_dq(&ip->i_gh); goto out_uninit; } } alloc_required = gfs2_write_alloc_required(ip, pos, len); if (alloc_required || gfs2_is_jdata(ip)) gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks); if (alloc_required) { struct gfs2_alloc_parms ap = { .aflags = 0, }; requested = data_blocks + ind_blocks; ap.target = requested; error = gfs2_quota_lock_check(ip, &ap); if (error) goto out_unlock; error = gfs2_inplace_reserve(ip, &ap); if (error) goto out_qunlock; } rblocks = RES_DINODE + ind_blocks; if (gfs2_is_jdata(ip)) rblocks += data_blocks ? data_blocks : 1; if (ind_blocks || data_blocks) rblocks += RES_STATFS + RES_QUOTA; if (&ip->i_inode == sdp->sd_rindex) rblocks += 2 * RES_STATFS; if (alloc_required) rblocks += gfs2_rg_blocks(ip, requested); error = gfs2_trans_begin(sdp, rblocks, PAGE_SIZE/sdp->sd_sb.sb_bsize); if (error) goto out_trans_fail; error = -ENOMEM; flags |= AOP_FLAG_NOFS; page = grab_cache_page_write_begin(mapping, index, flags); *pagep = page; if (unlikely(!page)) goto out_endtrans; if (gfs2_is_stuffed(ip)) { error = 0; if (pos + len > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) { error = gfs2_unstuff_dinode(ip, page); if (error == 0) goto prepare_write; } else if (!PageUptodate(page)) { error = stuffed_readpage(ip, page); } goto out; } prepare_write: error = __block_write_begin(page, from, len, gfs2_block_map); out: if (error == 0) return 0; unlock_page(page); put_page(page); gfs2_trans_end(sdp); if (pos + len > ip->i_inode.i_size) gfs2_trim_blocks(&ip->i_inode); goto out_trans_fail; out_endtrans: gfs2_trans_end(sdp); out_trans_fail: if (alloc_required) { gfs2_inplace_release(ip); out_qunlock: gfs2_quota_unlock(ip); } out_unlock: if (&ip->i_inode == sdp->sd_rindex) { gfs2_glock_dq(&m_ip->i_gh); gfs2_holder_uninit(&m_ip->i_gh); } gfs2_glock_dq(&ip->i_gh); out_uninit: gfs2_holder_uninit(&ip->i_gh); return error; } /** * adjust_fs_space - Adjusts the free space available due to gfs2_grow * @inode: the rindex inode */ static void adjust_fs_space(struct inode *inode) { struct gfs2_sbd *sdp = inode->i_sb->s_fs_info; struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode); struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master; struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local; struct buffer_head *m_bh, *l_bh; u64 fs_total, new_free; /* Total up the file system space, according to the latest rindex. */ fs_total = gfs2_ri_total(sdp); if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0) return; spin_lock(&sdp->sd_statfs_spin); gfs2_statfs_change_in(m_sc, m_bh->b_data + sizeof(struct gfs2_dinode)); if (fs_total > (m_sc->sc_total + l_sc->sc_total)) new_free = fs_total - (m_sc->sc_total + l_sc->sc_total); else new_free = 0; spin_unlock(&sdp->sd_statfs_spin); fs_warn(sdp, "File system extended by %llu blocks.\n", (unsigned long long)new_free); gfs2_statfs_change(sdp, new_free, new_free, 0); if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0) goto out; update_statfs(sdp, m_bh, l_bh); brelse(l_bh); out: brelse(m_bh); } /** * gfs2_stuffed_write_end - Write end for stuffed files * @inode: The inode * @dibh: The buffer_head containing the on-disk inode * @pos: The file position * @len: The length of the write * @copied: How much was actually copied by the VFS * @page: The page * * This copies the data from the page into the inode block after * the inode data structure itself. * * Returns: errno */ static int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh, loff_t pos, unsigned len, unsigned copied, struct page *page) { struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_sbd *sdp = GFS2_SB(inode); struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); u64 to = pos + copied; void *kaddr; unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode); BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode))); kaddr = kmap_atomic(page); memcpy(buf + pos, kaddr + pos, copied); memset(kaddr + pos + copied, 0, len - copied); flush_dcache_page(page); kunmap_atomic(kaddr); if (!PageUptodate(page)) SetPageUptodate(page); unlock_page(page); put_page(page); if (copied) { if (inode->i_size < to) i_size_write(inode, to); mark_inode_dirty(inode); } if (inode == sdp->sd_rindex) { adjust_fs_space(inode); sdp->sd_rindex_uptodate = 0; } brelse(dibh); gfs2_trans_end(sdp); if (inode == sdp->sd_rindex) { gfs2_glock_dq(&m_ip->i_gh); gfs2_holder_uninit(&m_ip->i_gh); } gfs2_glock_dq(&ip->i_gh); gfs2_holder_uninit(&ip->i_gh); return copied; } /** * gfs2_write_end * @file: The file to write to * @mapping: The address space to write to * @pos: The file position * @len: The length of the data * @copied: How much was actually copied by the VFS * @page: The page that has been written * @fsdata: The fsdata (unused in GFS2) * * The main write_end function for GFS2. We have a separate one for * stuffed files as they are slightly different, otherwise we just * put our locking around the VFS provided functions. * * Returns: errno */ static int gfs2_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { struct inode *inode = page->mapping->host; struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_sbd *sdp = GFS2_SB(inode); struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); struct buffer_head *dibh; unsigned int from = pos & (PAGE_SIZE - 1); unsigned int to = from + len; int ret; struct gfs2_trans *tr = current->journal_info; BUG_ON(!tr); BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL); ret = gfs2_meta_inode_buffer(ip, &dibh); if (unlikely(ret)) { unlock_page(page); put_page(page); goto failed; } if (gfs2_is_stuffed(ip)) return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page); if (!gfs2_is_writeback(ip)) gfs2_page_add_databufs(ip, page, from, to); ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata); if (tr->tr_num_buf_new) __mark_inode_dirty(inode, I_DIRTY_DATASYNC); else gfs2_trans_add_meta(ip->i_gl, dibh); if (inode == sdp->sd_rindex) { adjust_fs_space(inode); sdp->sd_rindex_uptodate = 0; } brelse(dibh); failed: gfs2_trans_end(sdp); gfs2_inplace_release(ip); if (ip->i_qadata && ip->i_qadata->qa_qd_num) gfs2_quota_unlock(ip); if (inode == sdp->sd_rindex) { gfs2_glock_dq(&m_ip->i_gh); gfs2_holder_uninit(&m_ip->i_gh); } gfs2_glock_dq(&ip->i_gh); gfs2_holder_uninit(&ip->i_gh); return ret; } /** * gfs2_set_page_dirty - Page dirtying function * @page: The page to dirty * * Returns: 1 if it dirtyed the page, or 0 otherwise */ static int gfs2_set_page_dirty(struct page *page) { SetPageChecked(page); return __set_page_dirty_buffers(page); } /** * gfs2_bmap - Block map function * @mapping: Address space info * @lblock: The block to map * * Returns: The disk address for the block or 0 on hole or error */ static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock) { struct gfs2_inode *ip = GFS2_I(mapping->host); struct gfs2_holder i_gh; sector_t dblock = 0; int error; error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh); if (error) return 0; if (!gfs2_is_stuffed(ip)) dblock = generic_block_bmap(mapping, lblock, gfs2_block_map); gfs2_glock_dq_uninit(&i_gh); return dblock; } static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh) { struct gfs2_bufdata *bd; lock_buffer(bh); gfs2_log_lock(sdp); clear_buffer_dirty(bh); bd = bh->b_private; if (bd) { if (!list_empty(&bd->bd_list) && !buffer_pinned(bh)) list_del_init(&bd->bd_list); else gfs2_remove_from_journal(bh, REMOVE_JDATA); } bh->b_bdev = NULL; clear_buffer_mapped(bh); clear_buffer_req(bh); clear_buffer_new(bh); gfs2_log_unlock(sdp); unlock_buffer(bh); } static void gfs2_invalidatepage(struct page *page, unsigned int offset, unsigned int length) { struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host); unsigned int stop = offset + length; int partial_page = (offset || length < PAGE_SIZE); struct buffer_head *bh, *head; unsigned long pos = 0; BUG_ON(!PageLocked(page)); if (!partial_page) ClearPageChecked(page); if (!page_has_buffers(page)) goto out; bh = head = page_buffers(page); do { if (pos + bh->b_size > stop) return; if (offset <= pos) gfs2_discard(sdp, bh); pos += bh->b_size; bh = bh->b_this_page; } while (bh != head); out: if (!partial_page) try_to_release_page(page, 0); } /** * gfs2_ok_for_dio - check that dio is valid on this file * @ip: The inode * @offset: The offset at which we are reading or writing * * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o) * 1 (to accept the i/o request) */ static int gfs2_ok_for_dio(struct gfs2_inode *ip, loff_t offset) { /* * Should we return an error here? I can't see that O_DIRECT for * a stuffed file makes any sense. For now we'll silently fall * back to buffered I/O */ if (gfs2_is_stuffed(ip)) return 0; if (offset >= i_size_read(&ip->i_inode)) return 0; return 1; } static ssize_t gfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; struct address_space *mapping = inode->i_mapping; struct gfs2_inode *ip = GFS2_I(inode); loff_t offset = iocb->ki_pos; struct gfs2_holder gh; int rv; /* * Deferred lock, even if its a write, since we do no allocation * on this path. All we need change is atime, and this lock mode * ensures that other nodes have flushed their buffered read caches * (i.e. their page cache entries for this inode). We do not, * unfortunately have the option of only flushing a range like * the VFS does. */ gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh); rv = gfs2_glock_nq(&gh); if (rv) goto out_uninit; rv = gfs2_ok_for_dio(ip, offset); if (rv != 1) goto out; /* dio not valid, fall back to buffered i/o */ /* * Now since we are holding a deferred (CW) lock at this point, you * might be wondering why this is ever needed. There is a case however * where we've granted a deferred local lock against a cached exclusive * glock. That is ok provided all granted local locks are deferred, but * it also means that it is possible to encounter pages which are * cached and possibly also mapped. So here we check for that and sort * them out ahead of the dio. The glock state machine will take care of * everything else. * * If in fact the cached glock state (gl->gl_state) is deferred (CW) in * the first place, mapping->nr_pages will always be zero. */ if (mapping->nrpages) { loff_t lstart = offset & ~(PAGE_SIZE - 1); loff_t len = iov_iter_count(iter); loff_t end = PAGE_ALIGN(offset + len) - 1; rv = 0; if (len == 0) goto out; if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags)) unmap_shared_mapping_range(ip->i_inode.i_mapping, offset, len); rv = filemap_write_and_wait_range(mapping, lstart, end); if (rv) goto out; if (iov_iter_rw(iter) == WRITE) truncate_inode_pages_range(mapping, lstart, end); } rv = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter, gfs2_get_block_direct, NULL, NULL, 0); out: gfs2_glock_dq(&gh); out_uninit: gfs2_holder_uninit(&gh); return rv; } /** * gfs2_releasepage - free the metadata associated with a page * @page: the page that's being released * @gfp_mask: passed from Linux VFS, ignored by us * * Call try_to_free_buffers() if the buffers in this page can be * released. * * Returns: 0 */ int gfs2_releasepage(struct page *page, gfp_t gfp_mask) { struct address_space *mapping = page->mapping; struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping); struct buffer_head *bh, *head; struct gfs2_bufdata *bd; if (!page_has_buffers(page)) return 0; /* * From xfs_vm_releasepage: mm accommodates an old ext3 case where * clean pages might not have had the dirty bit cleared. Thus, it can * send actual dirty pages to ->releasepage() via shrink_active_list(). * * As a workaround, we skip pages that contain dirty buffers below. * Once ->releasepage isn't called on dirty pages anymore, we can warn * on dirty buffers like we used to here again. */ gfs2_log_lock(sdp); spin_lock(&sdp->sd_ail_lock); head = bh = page_buffers(page); do { if (atomic_read(&bh->b_count)) goto cannot_release; bd = bh->b_private; if (bd && bd->bd_tr) goto cannot_release; if (buffer_dirty(bh) || WARN_ON(buffer_pinned(bh))) goto cannot_release; bh = bh->b_this_page; } while(bh != head); spin_unlock(&sdp->sd_ail_lock); head = bh = page_buffers(page); do { bd = bh->b_private; if (bd) { gfs2_assert_warn(sdp, bd->bd_bh == bh); if (!list_empty(&bd->bd_list)) list_del_init(&bd->bd_list); bd->bd_bh = NULL; bh->b_private = NULL; kmem_cache_free(gfs2_bufdata_cachep, bd); } bh = bh->b_this_page; } while (bh != head); gfs2_log_unlock(sdp); return try_to_free_buffers(page); cannot_release: spin_unlock(&sdp->sd_ail_lock); gfs2_log_unlock(sdp); return 0; } static const struct address_space_operations gfs2_writeback_aops = { .writepage = gfs2_writepage, .writepages = gfs2_writepages, .readpage = gfs2_readpage, .readpages = gfs2_readpages, .write_begin = gfs2_write_begin, .write_end = gfs2_write_end, .bmap = gfs2_bmap, .invalidatepage = gfs2_invalidatepage, .releasepage = gfs2_releasepage, .direct_IO = gfs2_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; static const struct address_space_operations gfs2_ordered_aops = { .writepage = gfs2_writepage, .writepages = gfs2_writepages, .readpage = gfs2_readpage, .readpages = gfs2_readpages, .write_begin = gfs2_write_begin, .write_end = gfs2_write_end, .set_page_dirty = gfs2_set_page_dirty, .bmap = gfs2_bmap, .invalidatepage = gfs2_invalidatepage, .releasepage = gfs2_releasepage, .direct_IO = gfs2_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; static const struct address_space_operations gfs2_jdata_aops = { .writepage = gfs2_jdata_writepage, .writepages = gfs2_jdata_writepages, .readpage = gfs2_readpage, .readpages = gfs2_readpages, .write_begin = gfs2_write_begin, .write_end = gfs2_write_end, .set_page_dirty = gfs2_set_page_dirty, .bmap = gfs2_bmap, .invalidatepage = gfs2_invalidatepage, .releasepage = gfs2_releasepage, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; void gfs2_set_aops(struct inode *inode) { struct gfs2_inode *ip = GFS2_I(inode); if (gfs2_is_writeback(ip)) inode->i_mapping->a_ops = &gfs2_writeback_aops; else if (gfs2_is_ordered(ip)) inode->i_mapping->a_ops = &gfs2_ordered_aops; else if (gfs2_is_jdata(ip)) inode->i_mapping->a_ops = &gfs2_jdata_aops; else BUG(); }