Merge branch 'at91/trng' into next/driver

1 files changed, 1500 insertions, 0 deletions

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
new file mode 100644
index 000000000000..8c37dde4c521
--- /dev/null
+++ b/fs/xfs/xfs_aops.c
@@ -0,0 +1,1500 @@
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include "xfs.h"
+#include "xfs_bit.h"
+#include "xfs_log.h"
+#include "xfs_inum.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_trans.h"
+#include "xfs_mount.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_dinode.h"
+#include "xfs_inode.h"
+#include "xfs_alloc.h"
+#include "xfs_error.h"
+#include "xfs_rw.h"
+#include "xfs_iomap.h"
+#include "xfs_vnodeops.h"
+#include "xfs_trace.h"
+#include "xfs_bmap.h"
+#include <linux/gfp.h>
+#include <linux/mpage.h>
+#include <linux/pagevec.h>
+#include <linux/writeback.h>
+
+
+/*
+ * Prime number of hash buckets since address is used as the key.
+ */
+#define NVSYNC          37
+#define to_ioend_wq(v)  (&xfs_ioend_wq[((unsigned long)v) % NVSYNC])
+static wait_queue_head_t xfs_ioend_wq[NVSYNC];
+
+void __init
+xfs_ioend_init(void)
+{
+        int i;
+
+        for (i = 0; i < NVSYNC; i++)
+                init_waitqueue_head(&xfs_ioend_wq[i]);
+}
+
+void
+xfs_ioend_wait(
+        xfs_inode_t     *ip)
+{
+        wait_queue_head_t *wq = to_ioend_wq(ip);
+
+        wait_event(*wq, (atomic_read(&ip->i_iocount) == 0));
+}
+
+STATIC void
+xfs_ioend_wake(
+        xfs_inode_t     *ip)
+{
+        if (atomic_dec_and_test(&ip->i_iocount))
+                wake_up(to_ioend_wq(ip));
+}
+
+void
+xfs_count_page_state(
+        struct page             *page,
+        int                     *delalloc,
+        int                     *unwritten)
+{
+        struct buffer_head      *bh, *head;
+
+        *delalloc = *unwritten = 0;
+
+        bh = head = page_buffers(page);
+        do {
+                if (buffer_unwritten(bh))
+                        (*unwritten) = 1;
+                else if (buffer_delay(bh))
+                        (*delalloc) = 1;
+        } while ((bh = bh->b_this_page) != head);
+}
+
+STATIC struct block_device *
+xfs_find_bdev_for_inode(
+        struct inode            *inode)
+{
+        struct xfs_inode        *ip = XFS_I(inode);
+        struct xfs_mount        *mp = ip->i_mount;
+
+        if (XFS_IS_REALTIME_INODE(ip))
+                return mp->m_rtdev_targp->bt_bdev;
+        else
+                return mp->m_ddev_targp->bt_bdev;
+}
+
+/*
+ * We're now finished for good with this ioend structure.
+ * Update the page state via the associated buffer_heads,
+ * release holds on the inode and bio, and finally free
+ * up memory.  Do not use the ioend after this.
+ */
+STATIC void
+xfs_destroy_ioend(
+        xfs_ioend_t             *ioend)
+{
+        struct buffer_head      *bh, *next;
+        struct xfs_inode        *ip = XFS_I(ioend->io_inode);
+
+        for (bh = ioend->io_buffer_head; bh; bh = next) {
+                next = bh->b_private;
+                bh->b_end_io(bh, !ioend->io_error);
+        }
+
+        /*
+         * Volume managers supporting multiple paths can send back ENODEV
+         * when the final path disappears.  In this case continuing to fill
+         * the page cache with dirty data which cannot be written out is
+         * evil, so prevent that.
+         */
+        if (unlikely(ioend->io_error == -ENODEV)) {
+                xfs_do_force_shutdown(ip->i_mount, SHUTDOWN_DEVICE_REQ,
+                                      __FILE__, __LINE__);
+        }
+
+        xfs_ioend_wake(ip);
+        mempool_free(ioend, xfs_ioend_pool);
+}
+
+/*
+ * If the end of the current ioend is beyond the current EOF,
+ * return the new EOF value, otherwise zero.
+ */
+STATIC xfs_fsize_t
+xfs_ioend_new_eof(
+        xfs_ioend_t             *ioend)
+{
+        xfs_inode_t             *ip = XFS_I(ioend->io_inode);
+        xfs_fsize_t             isize;
+        xfs_fsize_t             bsize;
+
+        bsize = ioend->io_offset + ioend->io_size;
+        isize = MAX(ip->i_size, ip->i_new_size);
+        isize = MIN(isize, bsize);
+        return isize > ip->i_d.di_size ? isize : 0;
+}
+
+/*
+ * Update on-disk file size now that data has been written to disk.  The
+ * current in-memory file size is i_size.  If a write is beyond eof i_new_size
+ * will be the intended file size until i_size is updated.  If this write does
+ * not extend all the way to the valid file size then restrict this update to
+ * the end of the write.
+ *
+ * This function does not block as blocking on the inode lock in IO completion
+ * can lead to IO completion order dependency deadlocks.. If it can't get the
+ * inode ilock it will return EAGAIN. Callers must handle this.
+ */
+STATIC int
+xfs_setfilesize(
+        xfs_ioend_t             *ioend)
+{
+        xfs_inode_t             *ip = XFS_I(ioend->io_inode);
+        xfs_fsize_t             isize;
+
+        if (unlikely(ioend->io_error))
+                return 0;
+
+        if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
+                return EAGAIN;
+
+        isize = xfs_ioend_new_eof(ioend);
+        if (isize) {
+                trace_xfs_setfilesize(ip, ioend->io_offset, ioend->io_size);
+                ip->i_d.di_size = isize;
+                xfs_mark_inode_dirty(ip);
+        }
+
+        xfs_iunlock(ip, XFS_ILOCK_EXCL);
+        return 0;
+}
+
+/*
+ * Schedule IO completion handling on the final put of an ioend.
+ */
+STATIC void
+xfs_finish_ioend(
+        struct xfs_ioend        *ioend)
+{
+        if (atomic_dec_and_test(&ioend->io_remaining)) {
+                if (ioend->io_type == IO_UNWRITTEN)
+                        queue_work(xfsconvertd_workqueue, &ioend->io_work);
+                else
+                        queue_work(xfsdatad_workqueue, &ioend->io_work);
+        }
+}
+
+/*
+ * IO write completion.
+ */
+STATIC void
+xfs_end_io(
+        struct work_struct *work)
+{
+        xfs_ioend_t     *ioend = container_of(work, xfs_ioend_t, io_work);
+        struct xfs_inode *ip = XFS_I(ioend->io_inode);
+        int             error = 0;
+
+        /*
+         * For unwritten extents we need to issue transactions to convert a
+         * range to normal written extens after the data I/O has finished.
+         */
+        if (ioend->io_type == IO_UNWRITTEN &&
+            likely(!ioend->io_error && !XFS_FORCED_SHUTDOWN(ip->i_mount))) {
+
+                error = xfs_iomap_write_unwritten(ip, ioend->io_offset,
+                                                 ioend->io_size);
+                if (error)
+                        ioend->io_error = error;
+        }
+
+        /*
+         * We might have to update the on-disk file size after extending
+         * writes.
+         */
+        error = xfs_setfilesize(ioend);
+        ASSERT(!error || error == EAGAIN);
+
+        /*
+         * If we didn't complete processing of the ioend, requeue it to the
+         * tail of the workqueue for another attempt later. Otherwise destroy
+         * it.
+         */
+        if (error == EAGAIN) {
+                atomic_inc(&ioend->io_remaining);
+                xfs_finish_ioend(ioend);
+                /* ensure we don't spin on blocked ioends */
+                delay(1);
+        } else {
+                if (ioend->io_iocb)
+                        aio_complete(ioend->io_iocb, ioend->io_result, 0);
+                xfs_destroy_ioend(ioend);
+        }
+}
+
+/*
+ * Call IO completion handling in caller context on the final put of an ioend.
+ */
+STATIC void
+xfs_finish_ioend_sync(
+        struct xfs_ioend        *ioend)
+{
+        if (atomic_dec_and_test(&ioend->io_remaining))
+                xfs_end_io(&ioend->io_work);
+}
+
+/*
+ * Allocate and initialise an IO completion structure.
+ * We need to track unwritten extent write completion here initially.
+ * We'll need to extend this for updating the ondisk inode size later
+ * (vs. incore size).
+ */
+STATIC xfs_ioend_t *
+xfs_alloc_ioend(
+        struct inode            *inode,
+        unsigned int            type)
+{
+        xfs_ioend_t             *ioend;
+
+        ioend = mempool_alloc(xfs_ioend_pool, GFP_NOFS);
+
+        /*
+         * Set the count to 1 initially, which will prevent an I/O
+         * completion callback from happening before we have started
+         * all the I/O from calling the completion routine too early.
+         */
+        atomic_set(&ioend->io_remaining, 1);
+        ioend->io_error = 0;
+        ioend->io_list = NULL;
+        ioend->io_type = type;
+        ioend->io_inode = inode;
+        ioend->io_buffer_head = NULL;
+        ioend->io_buffer_tail = NULL;
+        atomic_inc(&XFS_I(ioend->io_inode)->i_iocount);
+        ioend->io_offset = 0;
+        ioend->io_size = 0;
+        ioend->io_iocb = NULL;
+        ioend->io_result = 0;
+
+        INIT_WORK(&ioend->io_work, xfs_end_io);
+        return ioend;
+}
+
+STATIC int
+xfs_map_blocks(
+        struct inode            *inode,
+        loff_t                  offset,
+        struct xfs_bmbt_irec    *imap,
+        int                     type,
+        int                     nonblocking)
+{
+        struct xfs_inode        *ip = XFS_I(inode);
+        struct xfs_mount        *mp = ip->i_mount;
+        ssize_t                 count = 1 << inode->i_blkbits;
+        xfs_fileoff_t           offset_fsb, end_fsb;
+        int                     error = 0;
+        int                     bmapi_flags = XFS_BMAPI_ENTIRE;
+        int                     nimaps = 1;
+
+        if (XFS_FORCED_SHUTDOWN(mp))
+                return -XFS_ERROR(EIO);
+
+        if (type == IO_UNWRITTEN)
+                bmapi_flags |= XFS_BMAPI_IGSTATE;
+
+        if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) {
+                if (nonblocking)
+                        return -XFS_ERROR(EAGAIN);
+                xfs_ilock(ip, XFS_ILOCK_SHARED);
+        }
+
+        ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
+               (ip->i_df.if_flags & XFS_IFEXTENTS));
+        ASSERT(offset <= mp->m_maxioffset);
+
+        if (offset + count > mp->m_maxioffset)
+                count = mp->m_maxioffset - offset;
+        end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
+        offset_fsb = XFS_B_TO_FSBT(mp, offset);
+        error = xfs_bmapi(NULL, ip, offset_fsb, end_fsb - offset_fsb,
+                          bmapi_flags,  NULL, 0, imap, &nimaps, NULL);
+        xfs_iunlock(ip, XFS_ILOCK_SHARED);
+
+        if (error)
+                return -XFS_ERROR(error);
+
+        if (type == IO_DELALLOC &&
+            (!nimaps || isnullstartblock(imap->br_startblock))) {
+                error = xfs_iomap_write_allocate(ip, offset, count, imap);
+                if (!error)
+                        trace_xfs_map_blocks_alloc(ip, offset, count, type, imap);
+                return -XFS_ERROR(error);
+        }
+
+#ifdef DEBUG
+        if (type == IO_UNWRITTEN) {
+                ASSERT(nimaps);
+                ASSERT(imap->br_startblock != HOLESTARTBLOCK);
+                ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
+        }
+#endif
+        if (nimaps)
+                trace_xfs_map_blocks_found(ip, offset, count, type, imap);
+        return 0;
+}
+
+STATIC int
+xfs_imap_valid(
+        struct inode            *inode,
+        struct xfs_bmbt_irec    *imap,
+        xfs_off_t               offset)
+{
+        offset >>= inode->i_blkbits;
+
+        return offset >= imap->br_startoff &&
+                offset < imap->br_startoff + imap->br_blockcount;
+}
+
+/*
+ * BIO completion handler for buffered IO.
+ */
+STATIC void
+xfs_end_bio(
+        struct bio              *bio,
+        int                     error)
+{
+        xfs_ioend_t             *ioend = bio->bi_private;
+
+        ASSERT(atomic_read(&bio->bi_cnt) >= 1);
+        ioend->io_error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : error;
+
+        /* Toss bio and pass work off to an xfsdatad thread */
+        bio->bi_private = NULL;
+        bio->bi_end_io = NULL;
+        bio_put(bio);
+
+        xfs_finish_ioend(ioend);
+}
+
+STATIC void
+xfs_submit_ioend_bio(
+        struct writeback_control *wbc,
+        xfs_ioend_t             *ioend,
+        struct bio              *bio)
+{
+        atomic_inc(&ioend->io_remaining);
+        bio->bi_private = ioend;
+        bio->bi_end_io = xfs_end_bio;
+
+        /*
+         * If the I/O is beyond EOF we mark the inode dirty immediately
+         * but don't update the inode size until I/O completion.
+         */
+        if (xfs_ioend_new_eof(ioend))
+                xfs_mark_inode_dirty(XFS_I(ioend->io_inode));
+
+        submit_bio(wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE, bio);
+}
+
+STATIC struct bio *
+xfs_alloc_ioend_bio(
+        struct buffer_head      *bh)
+{
+        int                     nvecs = bio_get_nr_vecs(bh->b_bdev);
+        struct bio              *bio = bio_alloc(GFP_NOIO, nvecs);
+
+        ASSERT(bio->bi_private == NULL);
+        bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
+        bio->bi_bdev = bh->b_bdev;
+        return bio;
+}
+
+STATIC void
+xfs_start_buffer_writeback(
+        struct buffer_head      *bh)
+{
+        ASSERT(buffer_mapped(bh));
+        ASSERT(buffer_locked(bh));
+        ASSERT(!buffer_delay(bh));
+        ASSERT(!buffer_unwritten(bh));
+
+        mark_buffer_async_write(bh);
+        set_buffer_uptodate(bh);
+        clear_buffer_dirty(bh);
+}
+
+STATIC void
+xfs_start_page_writeback(
+        struct page             *page,
+        int                     clear_dirty,
+        int                     buffers)
+{
+        ASSERT(PageLocked(page));
+        ASSERT(!PageWriteback(page));
+        if (clear_dirty)
+                clear_page_dirty_for_io(page);
+        set_page_writeback(page);
+        unlock_page(page);
+        /* If no buffers on the page are to be written, finish it here */
+        if (!buffers)
+                end_page_writeback(page);
+}
+
+static inline int bio_add_buffer(struct bio *bio, struct buffer_head *bh)
+{
+        return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
+}
+
+/*
+ * Submit all of the bios for all of the ioends we have saved up, covering the
+ * initial writepage page and also any probed pages.
+ *
+ * Because we may have multiple ioends spanning a page, we need to start
+ * writeback on all the buffers before we submit them for I/O. If we mark the
+ * buffers as we got, then we can end up with a page that only has buffers
+ * marked async write and I/O complete on can occur before we mark the other
+ * buffers async write.
+ *
+ * The end result of this is that we trip a bug in end_page_writeback() because
+ * we call it twice for the one page as the code in end_buffer_async_write()
+ * assumes that all buffers on the page are started at the same time.
+ *
+ * The fix is two passes across the ioend list - one to start writeback on the
+ * buffer_heads, and then submit them for I/O on the second pass.
+ */
+STATIC void
+xfs_submit_ioend(
+        struct writeback_control *wbc,
+        xfs_ioend_t             *ioend)
+{
+        xfs_ioend_t             *head = ioend;
+        xfs_ioend_t             *next;
+        struct buffer_head      *bh;
+        struct bio              *bio;
+        sector_t                lastblock = 0;
+
+        /* Pass 1 - start writeback */
+        do {
+                next = ioend->io_list;
+                for (bh = ioend->io_buffer_head; bh; bh = bh->b_private)
+                        xfs_start_buffer_writeback(bh);
+        } while ((ioend = next) != NULL);
+
+        /* Pass 2 - submit I/O */
+        ioend = head;
+        do {
+                next = ioend->io_list;
+                bio = NULL;
+
+                for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
+
+                        if (!bio) {
+ retry:
+                                bio = xfs_alloc_ioend_bio(bh);
+                        } else if (bh->b_blocknr != lastblock + 1) {
+                                xfs_submit_ioend_bio(wbc, ioend, bio);
+                                goto retry;
+                        }
+
+                        if (bio_add_buffer(bio, bh) != bh->b_size) {
+                                xfs_submit_ioend_bio(wbc, ioend, bio);
+                                goto retry;
+                        }
+
+                        lastblock = bh->b_blocknr;
+                }
+                if (bio)
+                        xfs_submit_ioend_bio(wbc, ioend, bio);
+                xfs_finish_ioend(ioend);
+        } while ((ioend = next) != NULL);
+}
+
+/*
+ * Cancel submission of all buffer_heads so far in this endio.
+ * Toss the endio too.  Only ever called for the initial page
+ * in a writepage request, so only ever one page.
+ */
+STATIC void
+xfs_cancel_ioend(
+        xfs_ioend_t             *ioend)
+{
+        xfs_ioend_t             *next;
+        struct buffer_head      *bh, *next_bh;
+
+        do {
+                next = ioend->io_list;
+                bh = ioend->io_buffer_head;
+                do {
+                        next_bh = bh->b_private;
+                        clear_buffer_async_write(bh);
+                        unlock_buffer(bh);
+                } while ((bh = next_bh) != NULL);
+
+                xfs_ioend_wake(XFS_I(ioend->io_inode));
+                mempool_free(ioend, xfs_ioend_pool);
+        } while ((ioend = next) != NULL);
+}
+
+/*
+ * Test to see if we've been building up a completion structure for
+ * earlier buffers -- if so, we try to append to this ioend if we
+ * can, otherwise we finish off any current ioend and start another.
+ * Return true if we've finished the given ioend.
+ */
+STATIC void
+xfs_add_to_ioend(
+        struct inode            *inode,
+        struct buffer_head      *bh,
+        xfs_off_t               offset,
+        unsigned int            type,
+        xfs_ioend_t             **result,
+        int                     need_ioend)
+{
+        xfs_ioend_t             *ioend = *result;
+
+        if (!ioend || need_ioend || type != ioend->io_type) {
+                xfs_ioend_t     *previous = *result;
+
+                ioend = xfs_alloc_ioend(inode, type);
+                ioend->io_offset = offset;
+                ioend->io_buffer_head = bh;
+                ioend->io_buffer_tail = bh;
+                if (previous)
+                        previous->io_list = ioend;
+                *result = ioend;
+        } else {
+                ioend->io_buffer_tail->b_private = bh;
+                ioend->io_buffer_tail = bh;
+        }
+
+        bh->b_private = NULL;
+        ioend->io_size += bh->b_size;
+}
+
+STATIC void
+xfs_map_buffer(
+        struct inode            *inode,
+        struct buffer_head      *bh,
+        struct xfs_bmbt_irec    *imap,
+        xfs_off_t               offset)
+{
+        sector_t                bn;
+        struct xfs_mount        *m = XFS_I(inode)->i_mount;
+        xfs_off_t               iomap_offset = XFS_FSB_TO_B(m, imap->br_startoff);
+        xfs_daddr_t             iomap_bn = xfs_fsb_to_db(XFS_I(inode), imap->br_startblock);
+
+        ASSERT(imap->br_startblock != HOLESTARTBLOCK);
+        ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
+
+        bn = (iomap_bn >> (inode->i_blkbits - BBSHIFT)) +
+              ((offset - iomap_offset) >> inode->i_blkbits);
+
+        ASSERT(bn || XFS_IS_REALTIME_INODE(XFS_I(inode)));
+
+        bh->b_blocknr = bn;
+        set_buffer_mapped(bh);
+}
+
+STATIC void
+xfs_map_at_offset(
+        struct inode            *inode,
+        struct buffer_head      *bh,
+        struct xfs_bmbt_irec    *imap,
+        xfs_off_t               offset)
+{
+        ASSERT(imap->br_startblock != HOLESTARTBLOCK);
+        ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
+
+        xfs_map_buffer(inode, bh, imap, offset);
+        set_buffer_mapped(bh);
+        clear_buffer_delay(bh);
+        clear_buffer_unwritten(bh);
+}
+
+/*
+ * Test if a given page is suitable for writing as part of an unwritten
+ * or delayed allocate extent.
+ */
+STATIC int
+xfs_is_delayed_page(
+        struct page             *page,
+        unsigned int            type)
+{
+        if (PageWriteback(page))
+                return 0;
+
+        if (page->mapping && page_has_buffers(page)) {
+                struct buffer_head      *bh, *head;
+                int                     acceptable = 0;
+
+                bh = head = page_buffers(page);
+                do {
+                        if (buffer_unwritten(bh))
+                                acceptable = (type == IO_UNWRITTEN);
+                        else if (buffer_delay(bh))
+                                acceptable = (type == IO_DELALLOC);
+                        else if (buffer_dirty(bh) && buffer_mapped(bh))
+                                acceptable = (type == IO_OVERWRITE);
+                        else
+                                break;
+                } while ((bh = bh->b_this_page) != head);
+
+                if (acceptable)
+                        return 1;
+        }
+
+        return 0;
+}
+
+/*
+ * Allocate & map buffers for page given the extent map. Write it out.
+ * except for the original page of a writepage, this is called on
+ * delalloc/unwritten pages only, for the original page it is possible
+ * that the page has no mapping at all.
+ */
+STATIC int
+xfs_convert_page(
+        struct inode            *inode,
+        struct page             *page,
+        loff_t                  tindex,
+        struct xfs_bmbt_irec    *imap,
+        xfs_ioend_t             **ioendp,
+        struct writeback_control *wbc)
+{
+        struct buffer_head      *bh, *head;
+        xfs_off_t               end_offset;
+        unsigned long           p_offset;
+        unsigned int            type;
+        int                     len, page_dirty;
+        int                     count = 0, done = 0, uptodate = 1;
+        xfs_off_t               offset = page_offset(page);
+
+        if (page->index != tindex)
+                goto fail;
+        if (!trylock_page(page))
+                goto fail;
+        if (PageWriteback(page))
+                goto fail_unlock_page;
+        if (page->mapping != inode->i_mapping)
+                goto fail_unlock_page;
+        if (!xfs_is_delayed_page(page, (*ioendp)->io_type))
+                goto fail_unlock_page;
+
+        /*
+         * page_dirty is initially a count of buffers on the page before
+         * EOF and is decremented as we move each into a cleanable state.
+         *
+         * Derivation:
+         *
+         * End offset is the highest offset that this page should represent.
+         * If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
+         * will evaluate non-zero and be less than PAGE_CACHE_SIZE and
+         * hence give us the correct page_dirty count. On any other page,
+         * it will be zero and in that case we need page_dirty to be the
+         * count of buffers on the page.
+         */
+        end_offset = min_t(unsigned long long,
+                        (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
+                        i_size_read(inode));
+
+        len = 1 << inode->i_blkbits;
+        p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
+                                        PAGE_CACHE_SIZE);
+        p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
+        page_dirty = p_offset / len;
+
+        bh = head = page_buffers(page);
+        do {
+                if (offset >= end_offset)
+                        break;
+                if (!buffer_uptodate(bh))
+                        uptodate = 0;
+                if (!(PageUptodate(page) || buffer_uptodate(bh))) {
+                        done = 1;
+                        continue;
+                }
+
+                if (buffer_unwritten(bh) || buffer_delay(bh) ||
+                    buffer_mapped(bh)) {
+                        if (buffer_unwritten(bh))
+                                type = IO_UNWRITTEN;
+                        else if (buffer_delay(bh))
+                                type = IO_DELALLOC;
+                        else
+                                type = IO_OVERWRITE;
+
+                        if (!xfs_imap_valid(inode, imap, offset)) {
+                                done = 1;
+                                continue;
+                        }
+
+                        lock_buffer(bh);
+                        if (type != IO_OVERWRITE)
+                                xfs_map_at_offset(inode, bh, imap, offset);
+                        xfs_add_to_ioend(inode, bh, offset, type,
+                                         ioendp, done);
+
+                        page_dirty--;
+                        count++;
+                } else {
+                        done = 1;
+                }
+        } while (offset += len, (bh = bh->b_this_page) != head);
+
+        if (uptodate && bh == head)
+                SetPageUptodate(page);
+
+        if (count) {
+                if (--wbc->nr_to_write <= 0 &&
+                    wbc->sync_mode == WB_SYNC_NONE)
+                        done = 1;
+        }
+        xfs_start_page_writeback(page, !page_dirty, count);
+
+        return done;
+ fail_unlock_page:
+        unlock_page(page);
+ fail:
+        return 1;
+}
+
+/*
+ * Convert & write out a cluster of pages in the same extent as defined
+ * by mp and following the start page.
+ */
+STATIC void
+xfs_cluster_write(
+        struct inode            *inode,
+        pgoff_t                 tindex,
+        struct xfs_bmbt_irec    *imap,
+        xfs_ioend_t             **ioendp,
+        struct writeback_control *wbc,
+        pgoff_t                 tlast)
+{
+        struct pagevec          pvec;
+        int                     done = 0, i;
+
+        pagevec_init(&pvec, 0);
+        while (!done && tindex <= tlast) {
+                unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);
+
+                if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
+                        break;
+
+                for (i = 0; i < pagevec_count(&pvec); i++) {
+                        done = xfs_convert_page(inode, pvec.pages[i], tindex++,
+                                        imap, ioendp, wbc);
+                        if (done)
+                                break;
+                }
+
+                pagevec_release(&pvec);
+                cond_resched();
+        }
+}
+
+STATIC void
+xfs_vm_invalidatepage(
+        struct page             *page,
+        unsigned long           offset)
+{
+        trace_xfs_invalidatepage(page->mapping->host, page, offset);
+        block_invalidatepage(page, offset);
+}
+
+/*
+ * If the page has delalloc buffers on it, we need to punch them out before we
+ * invalidate the page. If we don't, we leave a stale delalloc mapping on the
+ * inode that can trip a BUG() in xfs_get_blocks() later on if a direct IO read
+ * is done on that same region - the delalloc extent is returned when none is
+ * supposed to be there.
+ *
+ * We prevent this by truncating away the delalloc regions on the page before
+ * invalidating it. Because they are delalloc, we can do this without needing a
+ * transaction. Indeed - if we get ENOSPC errors, we have to be able to do this
+ * truncation without a transaction as there is no space left for block
+ * reservation (typically why we see a ENOSPC in writeback).
+ *
+ * This is not a performance critical path, so for now just do the punching a
+ * buffer head at a time.
+ */
+STATIC void
+xfs_aops_discard_page(
+        struct page             *page)
+{
+        struct inode            *inode = page->mapping->host;
+        struct xfs_inode        *ip = XFS_I(inode);
+        struct buffer_head      *bh, *head;
+        loff_t                  offset = page_offset(page);
+
+        if (!xfs_is_delayed_page(page, IO_DELALLOC))
+                goto out_invalidate;
+
+        if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+                goto out_invalidate;
+
+        xfs_alert(ip->i_mount,
+                "page discard on page %p, inode 0x%llx, offset %llu.",
+                        page, ip->i_ino, offset);
+
+        xfs_ilock(ip, XFS_ILOCK_EXCL);
+        bh = head = page_buffers(page);
+        do {
+                int             error;
+                xfs_fileoff_t   start_fsb;
+
+                if (!buffer_delay(bh))
+                        goto next_buffer;
+
+                start_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
+                error = xfs_bmap_punch_delalloc_range(ip, start_fsb, 1);
+                if (error) {
+                        /* something screwed, just bail */
+                        if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+                                xfs_alert(ip->i_mount,
+                        "page discard unable to remove delalloc mapping.");
+                        }
+                        break;
+                }
+next_buffer:
+                offset += 1 << inode->i_blkbits;
+
+        } while ((bh = bh->b_this_page) != head);
+
+        xfs_iunlock(ip, XFS_ILOCK_EXCL);
+out_invalidate:
+        xfs_vm_invalidatepage(page, 0);
+        return;
+}
+
+/*
+ * Write out a dirty page.
+ *
+ * For delalloc space on the page we need to allocate space and flush it.
+ * For unwritten space on the page we need to start the conversion to
+ * regular allocated space.
+ * For any other dirty buffer heads on the page we should flush them.
+ */
+STATIC int
+xfs_vm_writepage(
+        struct page             *page,
+        struct writeback_control *wbc)
+{
+        struct inode            *inode = page->mapping->host;
+        struct buffer_head      *bh, *head;
+        struct xfs_bmbt_irec    imap;
+        xfs_ioend_t             *ioend = NULL, *iohead = NULL;
+        loff_t                  offset;
+        unsigned int            type;
+        __uint64_t              end_offset;
+        pgoff_t                 end_index, last_index;
+        ssize_t                 len;
+        int                     err, imap_valid = 0, uptodate = 1;
+        int                     count = 0;
+        int                     nonblocking = 0;
+
+        trace_xfs_writepage(inode, page, 0);
+
+        ASSERT(page_has_buffers(page));
+
+        /*
+         * Refuse to write the page out if we are called from reclaim context.
+         *
+         * This avoids stack overflows when called from deeply used stacks in
+         * random callers for direct reclaim or memcg reclaim.  We explicitly
+         * allow reclaim from kswapd as the stack usage there is relatively low.
+         *
+         * This should really be done by the core VM, but until that happens
+         * filesystems like XFS, btrfs and ext4 have to take care of this
+         * by themselves.
+         */
+        if ((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC)
+                goto redirty;
+
+        /*
+         * Given that we do not allow direct reclaim to call us, we should
+         * never be called while in a filesystem transaction.
+         */
+        if (WARN_ON(current->flags & PF_FSTRANS))
+                goto redirty;
+
+        /* Is this page beyond the end of the file? */
+        offset = i_size_read(inode);
+        end_index = offset >> PAGE_CACHE_SHIFT;
+        last_index = (offset - 1) >> PAGE_CACHE_SHIFT;
+        if (page->index >= end_index) {
+                if ((page->index >= end_index + 1) ||
+                    !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
+                        unlock_page(page);
+                        return 0;
+                }
+        }
+
+        end_offset = min_t(unsigned long long,
+                        (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
+                        offset);
+        len = 1 << inode->i_blkbits;
+
+        bh = head = page_buffers(page);
+        offset = page_offset(page);
+        type = IO_OVERWRITE;
+
+        if (wbc->sync_mode == WB_SYNC_NONE)
+                nonblocking = 1;
+
+        do {
+                int new_ioend = 0;
+
+                if (offset >= end_offset)
+                        break;
+                if (!buffer_uptodate(bh))
+                        uptodate = 0;
+
+                /*
+                 * set_page_dirty dirties all buffers in a page, independent
+                 * of their state.  The dirty state however is entirely
+                 * meaningless for holes (!mapped && uptodate), so skip
+                 * buffers covering holes here.
+                 */
+                if (!buffer_mapped(bh) && buffer_uptodate(bh)) {
+                        imap_valid = 0;
+                        continue;
+                }
+
+                if (buffer_unwritten(bh)) {
+                        if (type != IO_UNWRITTEN) {
+                                type = IO_UNWRITTEN;
+                                imap_valid = 0;
+                        }
+                } else if (buffer_delay(bh)) {
+                        if (type != IO_DELALLOC) {
+                                type = IO_DELALLOC;
+                                imap_valid = 0;
+                        }
+                } else if (buffer_uptodate(bh)) {
+                        if (type != IO_OVERWRITE) {
+                                type = IO_OVERWRITE;
+                                imap_valid = 0;
+                        }
+                } else {
+                        if (PageUptodate(page)) {
+                                ASSERT(buffer_mapped(bh));
+                                imap_valid = 0;
+                        }
+                        continue;
+                }
+
+                if (imap_valid)
+                        imap_valid = xfs_imap_valid(inode, &imap, offset);
+                if (!imap_valid) {
+                        /*
+                         * If we didn't have a valid mapping then we need to
+                         * put the new mapping into a separate ioend structure.
+                         * This ensures non-contiguous extents always have
+                         * separate ioends, which is particularly important
+                         * for unwritten extent conversion at I/O completion
+                         * time.
+                         */
+                        new_ioend = 1;
+                        err = xfs_map_blocks(inode, offset, &imap, type,
+                                             nonblocking);
+                        if (err)
+                                goto error;
+                        imap_valid = xfs_imap_valid(inode, &imap, offset);
+                }
+                if (imap_valid) {
+                        lock_buffer(bh);
+                        if (type != IO_OVERWRITE)
+                                xfs_map_at_offset(inode, bh, &imap, offset);
+                        xfs_add_to_ioend(inode, bh, offset, type, &ioend,
+                                         new_ioend);
+                        count++;
+                }
+
+                if (!iohead)
+                        iohead = ioend;
+
+        } while (offset += len, ((bh = bh->b_this_page) != head));
+
+        if (uptodate && bh == head)
+                SetPageUptodate(page);
+
+        xfs_start_page_writeback(page, 1, count);
+
+        if (ioend && imap_valid) {
+                xfs_off_t               end_index;
+
+                end_index = imap.br_startoff + imap.br_blockcount;
+
+                /* to bytes */
+                end_index <<= inode->i_blkbits;
+
+                /* to pages */
+                end_index = (end_index - 1) >> PAGE_CACHE_SHIFT;
+
+                /* check against file size */
+                if (end_index > last_index)
+                        end_index = last_index;
+
+                xfs_cluster_write(inode, page->index + 1, &imap, &ioend,
+                                  wbc, end_index);
+        }
+
+        if (iohead)
+                xfs_submit_ioend(wbc, iohead);
+
+        return 0;
+
+error:
+        if (iohead)
+                xfs_cancel_ioend(iohead);
+
+        if (err == -EAGAIN)
+                goto redirty;
+
+        xfs_aops_discard_page(page);
+        ClearPageUptodate(page);
+        unlock_page(page);
+        return err;
+
+redirty:
+        redirty_page_for_writepage(wbc, page);
+        unlock_page(page);
+        return 0;
+}
+
+STATIC int
+xfs_vm_writepages(
+        struct address_space    *mapping,
+        struct writeback_control *wbc)
+{
+        xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
+        return generic_writepages(mapping, wbc);
+}
+
+/*
+ * Called to move a page into cleanable state - and from there
+ * to be released. The page should already be clean. We always
+ * have buffer heads in this call.
+ *
+ * Returns 1 if the page is ok to release, 0 otherwise.
+ */
+STATIC int
+xfs_vm_releasepage(
+        struct page             *page,
+        gfp_t                   gfp_mask)
+{
+        int                     delalloc, unwritten;
+
+        trace_xfs_releasepage(page->mapping->host, page, 0);
+
+        xfs_count_page_state(page, &delalloc, &unwritten);
+
+        if (WARN_ON(delalloc))
+                return 0;
+        if (WARN_ON(unwritten))
+                return 0;
+
+        return try_to_free_buffers(page);
+}
+
+STATIC int
+__xfs_get_blocks(
+        struct inode            *inode,
+        sector_t                iblock,
+        struct buffer_head      *bh_result,
+        int                     create,
+        int                     direct)
+{
+        struct xfs_inode        *ip = XFS_I(inode);
+        struct xfs_mount        *mp = ip->i_mount;
+        xfs_fileoff_t           offset_fsb, end_fsb;
+        int                     error = 0;
+        int                     lockmode = 0;
+        struct xfs_bmbt_irec    imap;
+        int                     nimaps = 1;
+        xfs_off_t               offset;
+        ssize_t                 size;
+        int                     new = 0;
+
+        if (XFS_FORCED_SHUTDOWN(mp))
+                return -XFS_ERROR(EIO);
+
+        offset = (xfs_off_t)iblock << inode->i_blkbits;
+        ASSERT(bh_result->b_size >= (1 << inode->i_blkbits));
+        size = bh_result->b_size;
+
+        if (!create && direct && offset >= i_size_read(inode))
+                return 0;
+
+        if (create) {
+                lockmode = XFS_ILOCK_EXCL;
+                xfs_ilock(ip, lockmode);
+        } else {
+                lockmode = xfs_ilock_map_shared(ip);
+        }
+
+        ASSERT(offset <= mp->m_maxioffset);
+        if (offset + size > mp->m_maxioffset)
+                size = mp->m_maxioffset - offset;
+        end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + size);
+        offset_fsb = XFS_B_TO_FSBT(mp, offset);
+
+        error = xfs_bmapi(NULL, ip, offset_fsb, end_fsb - offset_fsb,
+                          XFS_BMAPI_ENTIRE,  NULL, 0, &imap, &nimaps, NULL);
+        if (error)
+                goto out_unlock;
+
+        if (create &&
+            (!nimaps ||
+             (imap.br_startblock == HOLESTARTBLOCK ||
+              imap.br_startblock == DELAYSTARTBLOCK))) {
+                if (direct) {
+                        error = xfs_iomap_write_direct(ip, offset, size,
+                                                       &imap, nimaps);
+                } else {
+                        error = xfs_iomap_write_delay(ip, offset, size, &imap);
+                }
+                if (error)
+                        goto out_unlock;
+
+                trace_xfs_get_blocks_alloc(ip, offset, size, 0, &imap);
+        } else if (nimaps) {
+                trace_xfs_get_blocks_found(ip, offset, size, 0, &imap);
+        } else {
+                trace_xfs_get_blocks_notfound(ip, offset, size);
+                goto out_unlock;
+        }
+        xfs_iunlock(ip, lockmode);
+
+        if (imap.br_startblock != HOLESTARTBLOCK &&
+            imap.br_startblock != DELAYSTARTBLOCK) {
+                /*
+                 * For unwritten extents do not report a disk address on
+                 * the read case (treat as if we're reading into a hole).
+                 */
+                if (create || !ISUNWRITTEN(&imap))
+                        xfs_map_buffer(inode, bh_result, &imap, offset);
+                if (create && ISUNWRITTEN(&imap)) {
+                        if (direct)
+                                bh_result->b_private = inode;
+                        set_buffer_unwritten(bh_result);
+                }
+        }
+
+        /*
+         * If this is a realtime file, data may be on a different device.
+         * to that pointed to from the buffer_head b_bdev currently.
+         */
+        bh_result->b_bdev = xfs_find_bdev_for_inode(inode);
+
+        /*
+         * If we previously allocated a block out beyond eof and we are now
+         * coming back to use it then we will need to flag it as new even if it
+         * has a disk address.
+         *
+         * With sub-block writes into unwritten extents we also need to mark
+         * the buffer as new so that the unwritten parts of the buffer gets
+         * correctly zeroed.
+         */
+        if (create &&
+            ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
+             (offset >= i_size_read(inode)) ||
+             (new || ISUNWRITTEN(&imap))))
+                set_buffer_new(bh_result);
+
+        if (imap.br_startblock == DELAYSTARTBLOCK) {
+                BUG_ON(direct);
+                if (create) {
+                        set_buffer_uptodate(bh_result);
+                        set_buffer_mapped(bh_result);
+                        set_buffer_delay(bh_result);
+                }
+        }
+
+        /*
+         * If this is O_DIRECT or the mpage code calling tell them how large
+         * the mapping is, so that we can avoid repeated get_blocks calls.
+         */
+        if (direct || size > (1 << inode->i_blkbits)) {
+                xfs_off_t               mapping_size;
+
+                mapping_size = imap.br_startoff + imap.br_blockcount - iblock;
+                mapping_size <<= inode->i_blkbits;
+
+                ASSERT(mapping_size > 0);
+                if (mapping_size > size)
+                        mapping_size = size;
+                if (mapping_size > LONG_MAX)
+                        mapping_size = LONG_MAX;
+
+                bh_result->b_size = mapping_size;
+        }
+
+        return 0;
+
+out_unlock:
+        xfs_iunlock(ip, lockmode);
+        return -error;
+}
+
+int
+xfs_get_blocks(
+        struct inode            *inode,
+        sector_t                iblock,
+        struct buffer_head      *bh_result,
+        int                     create)
+{
+        return __xfs_get_blocks(inode, iblock, bh_result, create, 0);
+}
+
+STATIC int
+xfs_get_blocks_direct(
+        struct inode            *inode,
+        sector_t                iblock,
+        struct buffer_head      *bh_result,
+        int                     create)
+{
+        return __xfs_get_blocks(inode, iblock, bh_result, create, 1);
+}
+
+/*
+ * Complete a direct I/O write request.
+ *
+ * If the private argument is non-NULL __xfs_get_blocks signals us that we
+ * need to issue a transaction to convert the range from unwritten to written
+ * extents.  In case this is regular synchronous I/O we just call xfs_end_io
+ * to do this and we are done.  But in case this was a successful AIO
+ * request this handler is called from interrupt context, from which we
+ * can't start transactions.  In that case offload the I/O completion to
+ * the workqueues we also use for buffered I/O completion.
+ */
+STATIC void
+xfs_end_io_direct_write(
+        struct kiocb            *iocb,
+        loff_t                  offset,
+        ssize_t                 size,
+        void                    *private,
+        int                     ret,
+        bool                    is_async)
+{
+        struct xfs_ioend        *ioend = iocb->private;
+        struct inode            *inode = ioend->io_inode;
+
+        /*
+         * blockdev_direct_IO can return an error even after the I/O
+         * completion handler was called.  Thus we need to protect
+         * against double-freeing.
+         */
+        iocb->private = NULL;
+
+        ioend->io_offset = offset;
+        ioend->io_size = size;
+        if (private && size > 0)
+                ioend->io_type = IO_UNWRITTEN;
+
+        if (is_async) {
+                /*
+                 * If we are converting an unwritten extent we need to delay
+                 * the AIO completion until after the unwrittent extent
+                 * conversion has completed, otherwise do it ASAP.
+                 */
+                if (ioend->io_type == IO_UNWRITTEN) {
+                        ioend->io_iocb = iocb;
+                        ioend->io_result = ret;
+                } else {
+                        aio_complete(iocb, ret, 0);
+                }
+                xfs_finish_ioend(ioend);
+        } else {
+                xfs_finish_ioend_sync(ioend);
+        }
+
+        /* XXX: probably should move into the real I/O completion handler */
+        inode_dio_done(inode);
+}
+
+STATIC ssize_t
+xfs_vm_direct_IO(
+        int                     rw,
+        struct kiocb            *iocb,
+        const struct iovec      *iov,
+        loff_t                  offset,
+        unsigned long           nr_segs)
+{
+        struct inode            *inode = iocb->ki_filp->f_mapping->host;
+        struct block_device     *bdev = xfs_find_bdev_for_inode(inode);
+        ssize_t                 ret;
+
+        if (rw & WRITE) {
+                iocb->private = xfs_alloc_ioend(inode, IO_DIRECT);
+
+                ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
+                                            offset, nr_segs,
+                                            xfs_get_blocks_direct,
+                                            xfs_end_io_direct_write, NULL, 0);
+                if (ret != -EIOCBQUEUED && iocb->private)
+                        xfs_destroy_ioend(iocb->private);
+        } else {
+                ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
+                                            offset, nr_segs,
+                                            xfs_get_blocks_direct,
+                                            NULL, NULL, 0);
+        }
+
+        return ret;
+}
+
+STATIC void
+xfs_vm_write_failed(
+        struct address_space    *mapping,
+        loff_t                  to)
+{
+        struct inode            *inode = mapping->host;
+
+        if (to > inode->i_size) {
+                /*
+                 * punch out the delalloc blocks we have already allocated. We
+                 * don't call xfs_setattr() to do this as we may be in the
+                 * middle of a multi-iovec write and so the vfs inode->i_size
+                 * will not match the xfs ip->i_size and so it will zero too
+                 * much. Hence we jus truncate the page cache to zero what is
+                 * necessary and punch the delalloc blocks directly.
+                 */
+                struct xfs_inode        *ip = XFS_I(inode);
+                xfs_fileoff_t           start_fsb;
+                xfs_fileoff_t           end_fsb;
+                int                     error;
+
+                truncate_pagecache(inode, to, inode->i_size);
+
+                /*
+                 * Check if there are any blocks that are outside of i_size
+                 * that need to be trimmed back.
+                 */
+                start_fsb = XFS_B_TO_FSB(ip->i_mount, inode->i_size) + 1;
+                end_fsb = XFS_B_TO_FSB(ip->i_mount, to);
+                if (end_fsb <= start_fsb)
+                        return;
+
+                xfs_ilock(ip, XFS_ILOCK_EXCL);
+                error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
+                                                        end_fsb - start_fsb);
+                if (error) {
+                        /* something screwed, just bail */
+                        if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+                                xfs_alert(ip->i_mount,
+                        "xfs_vm_write_failed: unable to clean up ino %lld",
+                                                ip->i_ino);
+                        }
+                }
+                xfs_iunlock(ip, XFS_ILOCK_EXCL);
+        }
+}
+
+STATIC int
+xfs_vm_write_begin(
+        struct file             *file,
+        struct address_space    *mapping,
+        loff_t                  pos,
+        unsigned                len,
+        unsigned                flags,
+        struct page             **pagep,
+        void                    **fsdata)
+{
+        int                     ret;
+
+        ret = block_write_begin(mapping, pos, len, flags | AOP_FLAG_NOFS,
+                                pagep, xfs_get_blocks);
+        if (unlikely(ret))
+                xfs_vm_write_failed(mapping, pos + len);
+        return ret;
+}
+
+STATIC int
+xfs_vm_write_end(
+        struct file             *file,
+        struct address_space    *mapping,
+        loff_t                  pos,
+        unsigned                len,
+        unsigned                copied,
+        struct page             *page,
+        void                    *fsdata)
+{
+        int                     ret;
+
+        ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
+        if (unlikely(ret < len))
+                xfs_vm_write_failed(mapping, pos + len);
+        return ret;
+}
+
+STATIC sector_t
+xfs_vm_bmap(
+        struct address_space    *mapping,
+        sector_t                block)
+{
+        struct inode            *inode = (struct inode *)mapping->host;
+        struct xfs_inode        *ip = XFS_I(inode);
+
+        trace_xfs_vm_bmap(XFS_I(inode));
+        xfs_ilock(ip, XFS_IOLOCK_SHARED);
+        xfs_flush_pages(ip, (xfs_off_t)0, -1, 0, FI_REMAPF);
+        xfs_iunlock(ip, XFS_IOLOCK_SHARED);
+        return generic_block_bmap(mapping, block, xfs_get_blocks);
+}
+
+STATIC int
+xfs_vm_readpage(
+        struct file             *unused,
+        struct page             *page)
+{
+        return mpage_readpage(page, xfs_get_blocks);
+}
+
+STATIC int
+xfs_vm_readpages(
+        struct file             *unused,
+        struct address_space    *mapping,
+        struct list_head        *pages,
+        unsigned                nr_pages)
+{
+        return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
+}
+
+const struct address_space_operations xfs_address_space_operations = {
+        .readpage               = xfs_vm_readpage,
+        .readpages              = xfs_vm_readpages,
+        .writepage              = xfs_vm_writepage,
+        .writepages             = xfs_vm_writepages,
+        .releasepage            = xfs_vm_releasepage,
+        .invalidatepage         = xfs_vm_invalidatepage,
+        .write_begin            = xfs_vm_write_begin,
+        .write_end              = xfs_vm_write_end,
+        .bmap                   = xfs_vm_bmap,
+        .direct_IO              = xfs_vm_direct_IO,
+        .migratepage            = buffer_migrate_page,
+        .is_partially_uptodate  = block_is_partially_uptodate,
+        .error_remove_page      = generic_error_remove_page,
+};