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Diffstat (limited to 'fs/xfs/xfs_aops.c')
-rw-r--r--fs/xfs/xfs_aops.c1500
1 files changed, 1500 insertions, 0 deletions
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
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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,
+};