--- /dev/null
+/*
+ * 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();
+}
+
Code Review / kvmfornfv.git / blobdiff