1 files changed, 1145 insertions, 0 deletions

diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
new file mode 100644
index 000000000000..03ebb439ace0
--- /dev/null
+++ b/fs/gfs2/aops.c
@@ -0,0 +1,1145 @@
+/*
+ * 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 "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_bh(ip->i_gl, bh, 0);
+        }
+}
+
+/**
+ * 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);
+                goto out;
+        }
+        return 1;
+redirty:
+        redirty_page_for_writepage(wbc, page);
+out:
+        unlock_page(page);
+        return 0;
+}
+
+/**
+ * gfs2_writeback_writepage - Write page for writeback mappings
+ * @page: The page
+ * @wbc: The writeback control
+ *
+ */
+
+static int gfs2_writeback_writepage(struct page *page,
+                                    struct writeback_control *wbc)
+{
+        int ret;
+
+        ret = gfs2_writepage_common(page, wbc);
+        if (ret <= 0)
+                return ret;
+
+        ret = mpage_writepage(page, gfs2_get_block_noalloc, wbc);
+        if (ret == -EAGAIN)
+                ret = block_write_full_page(page, gfs2_get_block_noalloc, wbc);
+        return ret;
+}
+
+/**
+ * gfs2_ordered_writepage - Write page for ordered data files
+ * @page: The page to write
+ * @wbc: The writeback control
+ *
+ */
+
+static int gfs2_ordered_writepage(struct page *page,
+                                  struct writeback_control *wbc)
+{
+        struct inode *inode = page->mapping->host;
+        struct gfs2_inode *ip = GFS2_I(inode);
+        int ret;
+
+        ret = gfs2_writepage_common(page, wbc);
+        if (ret <= 0)
+                return ret;
+
+        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, inode->i_sb->s_blocksize-1);
+        return block_write_full_page(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_writeback_writepages - Write a bunch of dirty pages back to disk
+ * @mapping: The mapping to write
+ * @wbc: Write-back control
+ *
+ * For the data=writeback case we can already ignore buffer heads
+ * and write whole extents at once. This is a big reduction in the
+ * number of I/O requests we send and the bmap calls we make in this case.
+ */
+static int gfs2_writeback_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)
+{
+        struct inode *inode = mapping->host;
+        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 = i_size & (PAGE_CACHE_SIZE-1);
+        unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize);
+        struct backing_dev_info *bdi = mapping->backing_dev_info;
+        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];
+
+                lock_page(page);
+
+                if (unlikely(page->mapping != mapping)) {
+                        unlock_page(page);
+                        continue;
+                }
+
+                if (!wbc->range_cyclic && page->index > end) {
+                        ret = 1;
+                        unlock_page(page);
+                        continue;
+                }
+
+                if (wbc->sync_mode != WB_SYNC_NONE)
+                        wait_on_page_writeback(page);
+
+                if (PageWriteback(page) ||
+                    !clear_page_dirty_for_io(page)) {
+                        unlock_page(page);
+                        continue;
+                }
+
+                /* Is the page fully outside i_size? (truncate in progress) */
+                if (page->index > end_index || (page->index == end_index && !offset)) {
+                        page->mapping->a_ops->invalidatepage(page, 0);
+                        unlock_page(page);
+                        continue;
+                }
+
+                ret = __gfs2_jdata_writepage(page, wbc);
+
+                if (ret || (--(wbc->nr_to_write) <= 0))
+                        ret = 1;
+                if (wbc->nonblocking && bdi_write_congested(bdi)) {
+                        wbc->encountered_congestion = 1;
+                        ret = 1;
+                }
+
+        }
+        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)
+{
+        struct backing_dev_info *bdi = mapping->backing_dev_info;
+        int ret = 0;
+        int done = 0;
+        struct pagevec pvec;
+        int nr_pages;
+        pgoff_t index;
+        pgoff_t end;
+        int scanned = 0;
+        int range_whole = 0;
+
+        if (wbc->nonblocking && bdi_write_congested(bdi)) {
+                wbc->encountered_congestion = 1;
+                return 0;
+        }
+
+        pagevec_init(&pvec, 0);
+        if (wbc->range_cyclic) {
+                index = mapping->writeback_index; /* Start from prev offset */
+                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;
+                scanned = 1;
+        }
+
+retry:
+         while (!done && (index <= end) &&
+                (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+                                               PAGECACHE_TAG_DIRTY,
+                                               min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
+                scanned = 1;
+                ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end);
+                if (ret)
+                        done = 1;
+                if (ret > 0)
+                        ret = 0;
+
+                pagevec_release(&pvec);
+                cond_resched();
+        }
+
+        if (!scanned && !done) {
+                /*
+                 * We hit the last page and there is more work to be done: wrap
+                 * back to the start of the file
+                 */
+                scanned = 1;
+                index = 0;
+                goto retry;
+        }
+
+        if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+                mapping->writeback_index = 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);
+                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;
+        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, KM_USER0);
+        memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
+               ip->i_disksize);
+        memset(kaddr + ip->i_disksize, 0, PAGE_CACHE_SIZE - ip->i_disksize);
+        kunmap_atomic(kaddr, KM_USER0);
+        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
+ * @ra_state: The readahead state (or NULL for no readahead)
+ * @buf: The buffer to fill
+ * @pos: The file position
+ * @size: The amount to read
+ *
+ */
+
+int gfs2_internal_read(struct gfs2_inode *ip, struct file_ra_state *ra_state,
+                       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, KM_USER0);
+                memcpy(buf + copied, p + offset, amt);
+                kunmap_atomic(p, KM_USER0);
+                mark_page_accessed(page);
+                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);
+        unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
+        int alloc_required;
+        int error = 0;
+        struct gfs2_alloc *al;
+        pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+        unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+        unsigned to = from + len;
+        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;
+
+        error = gfs2_write_alloc_required(ip, pos, len, &alloc_required);
+        if (error)
+                goto out_unlock;
+
+        if (alloc_required || gfs2_is_jdata(ip))
+                gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
+
+        if (alloc_required) {
+                al = gfs2_alloc_get(ip);
+                if (!al) {
+                        error = -ENOMEM;
+                        goto out_unlock;
+                }
+
+                error = gfs2_quota_lock_check(ip);
+                if (error)
+                        goto out_alloc_put;
+
+                al->al_requested = data_blocks + ind_blocks;
+                error = gfs2_inplace_reserve(ip);
+                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;
+
+        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_prepare_write(page, from, to, gfs2_block_map);
+out:
+        if (error == 0)
+                return 0;
+
+        page_cache_release(page);
+        if (pos + len > ip->i_inode.i_size)
+                vmtruncate(&ip->i_inode, ip->i_inode.i_size);
+out_endtrans:
+        gfs2_trans_end(sdp);
+out_trans_fail:
+        if (alloc_required) {
+                gfs2_inplace_release(ip);
+out_qunlock:
+                gfs2_quota_unlock(ip);
+out_alloc_put:
+                gfs2_alloc_put(ip);
+        }
+out_unlock:
+        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_statfs_change_host *m_sc = &sdp->sd_statfs_master;
+        struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
+        u64 fs_total, new_free;
+
+        /* Total up the file system space, according to the latest rindex. */
+        fs_total = gfs2_ri_total(sdp);
+
+        spin_lock(&sdp->sd_statfs_spin);
+        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);
+}
+
+/**
+ * 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);
+        u64 to = pos + copied;
+        void *kaddr;
+        unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode);
+        struct gfs2_dinode *di = (struct gfs2_dinode *)dibh->b_data;
+
+        BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode)));
+        kaddr = kmap_atomic(page, KM_USER0);
+        memcpy(buf + pos, kaddr + pos, copied);
+        memset(kaddr + pos + copied, 0, len - copied);
+        flush_dcache_page(page);
+        kunmap_atomic(kaddr, KM_USER0);
+
+        if (!PageUptodate(page))
+                SetPageUptodate(page);
+        unlock_page(page);
+        page_cache_release(page);
+
+        if (copied) {
+                if (inode->i_size < to) {
+                        i_size_write(inode, to);
+                        ip->i_disksize = inode->i_size;
+                }
+                gfs2_dinode_out(ip, di);
+                mark_inode_dirty(inode);
+        }
+
+        if (inode == sdp->sd_rindex)
+                adjust_fs_space(inode);
+
+        brelse(dibh);
+        gfs2_trans_end(sdp);
+        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 buffer_head *dibh;
+        struct gfs2_alloc *al = ip->i_alloc;
+        unsigned int from = pos & (PAGE_CACHE_SIZE - 1);
+        unsigned int to = from + len;
+        int ret;
+
+        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;
+        }
+
+        gfs2_trans_add_bh(ip->i_gl, dibh, 1);
+
+        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 (ret > 0) {
+                if (inode->i_size > ip->i_disksize)
+                        ip->i_disksize = inode->i_size;
+                gfs2_dinode_out(ip, dibh->b_data);
+                mark_inode_dirty(inode);
+        }
+
+        if (inode == sdp->sd_rindex)
+                adjust_fs_space(inode);
+
+        brelse(dibh);
+        gfs2_trans_end(sdp);
+failed:
+        if (al) {
+                gfs2_inplace_release(ip);
+                gfs2_quota_unlock(ip);
+                gfs2_alloc_put(ip);
+        }
+        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_le.le_list) && !buffer_pinned(bh))
+                        list_del_init(&bd->bd_le.le_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 long offset)
+{
+        struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
+        struct buffer_head *bh, *head;
+        unsigned long pos = 0;
+
+        BUG_ON(!PageLocked(page));
+        if (offset == 0)
+                ClearPageChecked(page);
+        if (!page_has_buffers(page))
+                goto out;
+
+        bh = head = page_buffers(page);
+        do {
+                if (offset <= pos)
+                        gfs2_discard(sdp, bh);
+                pos += bh->b_size;
+                bh = bh->b_this_page;
+        } while (bh != head);
+out:
+        if (offset == 0)
+                try_to_release_page(page, 0);
+}
+
+/**
+ * gfs2_ok_for_dio - check that dio is valid on this file
+ * @ip: The inode
+ * @rw: READ or WRITE
+ * @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, int rw, 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(int rw, struct kiocb *iocb,
+                              const struct iovec *iov, loff_t offset,
+                              unsigned long nr_segs)
+{
+        struct file *file = iocb->ki_filp;
+        struct inode *inode = file->f_mapping->host;
+        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, rw, offset);
+        if (rv != 1)
+                goto out; /* dio not valid, fall back to buffered i/o */
+
+        rv = blockdev_direct_IO_no_locking(rw, iocb, inode, inode->i_sb->s_bdev,
+                                           iov, offset, nr_segs,
+                                           gfs2_get_block_direct, NULL);
+out:
+        gfs2_glock_dq_m(1, &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 inode *aspace = page->mapping->host;
+        struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
+        struct buffer_head *bh, *head;
+        struct gfs2_bufdata *bd;
+
+        if (!page_has_buffers(page))
+                return 0;
+
+        gfs2_log_lock(sdp);
+        head = bh = page_buffers(page);
+        do {
+                if (atomic_read(&bh->b_count))
+                        goto cannot_release;
+                bd = bh->b_private;
+                if (bd && bd->bd_ail)
+                        goto cannot_release;
+                gfs2_assert_warn(sdp, !buffer_pinned(bh));
+                gfs2_assert_warn(sdp, !buffer_dirty(bh));
+                bh = bh->b_this_page;
+        } while(bh != head);
+        gfs2_log_unlock(sdp);
+
+        head = bh = page_buffers(page);
+        do {
+                gfs2_log_lock(sdp);
+                bd = bh->b_private;
+                if (bd) {
+                        gfs2_assert_warn(sdp, bd->bd_bh == bh);
+                        gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
+                        if (!list_empty(&bd->bd_le.le_list)) {
+                                if (!buffer_pinned(bh))
+                                        list_del_init(&bd->bd_le.le_list);
+                                else
+                                        bd = NULL;
+                        }
+                        if (bd)
+                                bd->bd_bh = NULL;
+                        bh->b_private = NULL;
+                }
+                gfs2_log_unlock(sdp);
+                if (bd)
+                        kmem_cache_free(gfs2_bufdata_cachep, bd);
+
+                bh = bh->b_this_page;
+        } while (bh != head);
+
+        return try_to_free_buffers(page);
+cannot_release:
+        gfs2_log_unlock(sdp);
+        return 0;
+}
+
+static const struct address_space_operations gfs2_writeback_aops = {
+        .writepage = gfs2_writeback_writepage,
+        .writepages = gfs2_writeback_writepages,
+        .readpage = gfs2_readpage,
+        .readpages = gfs2_readpages,
+        .sync_page = block_sync_page,
+        .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,
+};
+
+static const struct address_space_operations gfs2_ordered_aops = {
+        .writepage = gfs2_ordered_writepage,
+        .readpage = gfs2_readpage,
+        .readpages = gfs2_readpages,
+        .sync_page = block_sync_page,
+        .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,
+};
+
+static const struct address_space_operations gfs2_jdata_aops = {
+        .writepage = gfs2_jdata_writepage,
+        .writepages = gfs2_jdata_writepages,
+        .readpage = gfs2_readpage,
+        .readpages = gfs2_readpages,
+        .sync_page = block_sync_page,
+        .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,
+};
+
+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();
+}
+