diff options
Diffstat (limited to 'kernel/fs/gfs2/aops.c')
| -rw-r--r-- | kernel/fs/gfs2/aops.c | 1229 |
1 files changed, 1229 insertions, 0 deletions
diff --git a/kernel/fs/gfs2/aops.c b/kernel/fs/gfs2/aops.c new file mode 100644 index 000000000..5551fea0a --- /dev/null +++ b/kernel/fs/gfs2/aops.c @@ -0,0 +1,1229 @@ +/* + * 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_CACHE_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_CACHE_SIZE-1); + if (page->index > end_index || (page->index == end_index && !offset)) { + page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_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); +} + +/** + * __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, + (1 << BH_Dirty)|(1 << BH_Uptodate)); + } + gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1); + } + return block_write_full_page(page, gfs2_get_block_noalloc, wbc); +} + +/** + * gfs2_jdata_writepage - Write complete page + * @page: Page to write + * + * Returns: errno + * + */ + +static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc) +{ + struct inode *inode = page->mapping->host; + struct gfs2_sbd *sdp = GFS2_SB(inode); + int ret; + int done_trans = 0; + + if (PageChecked(page)) { + if (wbc->sync_mode != WB_SYNC_ALL) + goto out_ignore; + ret = gfs2_trans_begin(sdp, RES_DINODE + 1, 0); + if (ret) + goto out_ignore; + done_trans = 1; + } + ret = gfs2_writepage_common(page, wbc); + if (ret > 0) + ret = __gfs2_jdata_writepage(page, wbc); + if (done_trans) + gfs2_trans_end(sdp); + return ret; + +out_ignore: + redirty_page_for_writepage(wbc, page); + 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 + * @writepage: The writepage function to call for each page + * @pvec: The vector of pages + * @nr_pages: The number of pages to write + * + * 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_CACHE_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 + * @writepage: The writepage function to call + * @data: The data to pass to writepage + * + * 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_CACHE_SHIFT; + end = wbc->range_end >> PAGE_CACHE_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_CACHE_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_CACHE_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_CACHE_SIZE; + unsigned offset = *pos & (PAGE_CACHE_SIZE - 1); + unsigned copied = 0; + unsigned amt; + struct page *page; + void *p; + + do { + amt = size - copied; + if (offset + size > PAGE_CACHE_SIZE) + amt = PAGE_CACHE_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); + page_cache_release(page); + copied += amt; + index++; + offset = 0; + } while(copied < size); + (*pos) += size; + return size; +} + +/** + * gfs2_readpages - Read a bunch of pages at once + * + * 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_CACHE_SHIFT; + unsigned from = pos & (PAGE_CACHE_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_CACHE_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); + page_cache_release(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); + page_cache_release(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: + * @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_CACHE_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); + page_cache_release(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_res->rs_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, current->journal_info, 0); + } + 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_CACHE_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, + loff_t offset) +{ + 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); + 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) + return rv; + 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_CACHE_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, + offset, gfs2_get_block_direct, NULL, NULL, 0); +out: + gfs2_glock_dq(&gh); + 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; + + 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_pinned(bh) || buffer_dirty(bh)) + goto not_possible; + 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); + +not_possible: /* Should never happen */ + WARN_ON(buffer_dirty(bh)); + WARN_ON(buffer_pinned(bh)); +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(); +} + |