[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/fs/xfs/xfs_aops.c b/src/kernel/linux/v4.14/fs/xfs/xfs_aops.c
new file mode 100644
index 0000000..b0cccf8
--- /dev/null
+++ b/src/kernel/linux/v4.14/fs/xfs/xfs_aops.c
@@ -0,0 +1,1494 @@
+/*
+ * 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_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_trans.h"
+#include "xfs_inode_item.h"
+#include "xfs_alloc.h"
+#include "xfs_error.h"
+#include "xfs_iomap.h"
+#include "xfs_trace.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_util.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_reflink.h"
+#include <linux/gfp.h>
+#include <linux/mpage.h>
+#include <linux/pagevec.h>
+#include <linux/writeback.h>
+
+/*
+ * structure owned by writepages passed to individual writepage calls
+ */
+struct xfs_writepage_ctx {
+ struct xfs_bmbt_irec imap;
+ bool imap_valid;
+ unsigned int io_type;
+ struct xfs_ioend *ioend;
+ sector_t last_block;
+};
+
+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);
+}
+
+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;
+}
+
+struct dax_device *
+xfs_find_daxdev_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_daxdev;
+ else
+ return mp->m_ddev_targp->bt_daxdev;
+}
+
+/*
+ * We're now finished for good with this page. Update the page state via the
+ * associated buffer_heads, paying attention to the start and end offsets that
+ * we need to process on the page.
+ *
+ * Note that we open code the action in end_buffer_async_write here so that we
+ * only have to iterate over the buffers attached to the page once. This is not
+ * only more efficient, but also ensures that we only calls end_page_writeback
+ * at the end of the iteration, and thus avoids the pitfall of having the page
+ * and buffers potentially freed after every call to end_buffer_async_write.
+ */
+static void
+xfs_finish_page_writeback(
+ struct inode *inode,
+ struct bio_vec *bvec,
+ int error)
+{
+ struct buffer_head *head = page_buffers(bvec->bv_page), *bh = head;
+ bool busy = false;
+ unsigned int off = 0;
+ unsigned long flags;
+
+ ASSERT(bvec->bv_offset < PAGE_SIZE);
+ ASSERT((bvec->bv_offset & (i_blocksize(inode) - 1)) == 0);
+ ASSERT(bvec->bv_offset + bvec->bv_len <= PAGE_SIZE);
+ ASSERT((bvec->bv_len & (i_blocksize(inode) - 1)) == 0);
+
+ local_irq_save(flags);
+ bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
+ do {
+ if (off >= bvec->bv_offset &&
+ off < bvec->bv_offset + bvec->bv_len) {
+ ASSERT(buffer_async_write(bh));
+ ASSERT(bh->b_end_io == NULL);
+
+ if (error) {
+ mark_buffer_write_io_error(bh);
+ clear_buffer_uptodate(bh);
+ SetPageError(bvec->bv_page);
+ } else {
+ set_buffer_uptodate(bh);
+ }
+ clear_buffer_async_write(bh);
+ unlock_buffer(bh);
+ } else if (buffer_async_write(bh)) {
+ ASSERT(buffer_locked(bh));
+ busy = true;
+ }
+ off += bh->b_size;
+ } while ((bh = bh->b_this_page) != head);
+ bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
+ local_irq_restore(flags);
+
+ if (!busy)
+ end_page_writeback(bvec->bv_page);
+}
+
+/*
+ * We're now finished for good with this ioend structure. Update the page
+ * state, release holds on bios, and finally free up memory. Do not use the
+ * ioend after this.
+ */
+STATIC void
+xfs_destroy_ioend(
+ struct xfs_ioend *ioend,
+ int error)
+{
+ struct inode *inode = ioend->io_inode;
+ struct bio *bio = &ioend->io_inline_bio;
+ struct bio *last = ioend->io_bio, *next;
+ u64 start = bio->bi_iter.bi_sector;
+ bool quiet = bio_flagged(bio, BIO_QUIET);
+
+ for (bio = &ioend->io_inline_bio; bio; bio = next) {
+ struct bio_vec *bvec;
+ int i;
+
+ /*
+ * For the last bio, bi_private points to the ioend, so we
+ * need to explicitly end the iteration here.
+ */
+ if (bio == last)
+ next = NULL;
+ else
+ next = bio->bi_private;
+
+ /* walk each page on bio, ending page IO on them */
+ bio_for_each_segment_all(bvec, bio, i)
+ xfs_finish_page_writeback(inode, bvec, error);
+
+ bio_put(bio);
+ }
+
+ if (unlikely(error && !quiet)) {
+ xfs_err_ratelimited(XFS_I(inode)->i_mount,
+ "writeback error on sector %llu", start);
+ }
+}
+
+/*
+ * Fast and loose check if this write could update the on-disk inode size.
+ */
+static inline bool xfs_ioend_is_append(struct xfs_ioend *ioend)
+{
+ return ioend->io_offset + ioend->io_size >
+ XFS_I(ioend->io_inode)->i_d.di_size;
+}
+
+STATIC int
+xfs_setfilesize_trans_alloc(
+ struct xfs_ioend *ioend)
+{
+ struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount;
+ struct xfs_trans *tp;
+ int error;
+
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
+ if (error)
+ return error;
+
+ ioend->io_append_trans = tp;
+
+ /*
+ * We may pass freeze protection with a transaction. So tell lockdep
+ * we released it.
+ */
+ __sb_writers_release(ioend->io_inode->i_sb, SB_FREEZE_FS);
+ /*
+ * We hand off the transaction to the completion thread now, so
+ * clear the flag here.
+ */
+ current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+ return 0;
+}
+
+/*
+ * Update on-disk file size now that data has been written to disk.
+ */
+STATIC int
+__xfs_setfilesize(
+ struct xfs_inode *ip,
+ struct xfs_trans *tp,
+ xfs_off_t offset,
+ size_t size)
+{
+ xfs_fsize_t isize;
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ isize = xfs_new_eof(ip, offset + size);
+ if (!isize) {
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ xfs_trans_cancel(tp);
+ return 0;
+ }
+
+ trace_xfs_setfilesize(ip, offset, size);
+
+ ip->i_d.di_size = isize;
+ xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+ xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+ return xfs_trans_commit(tp);
+}
+
+int
+xfs_setfilesize(
+ struct xfs_inode *ip,
+ xfs_off_t offset,
+ size_t size)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_trans *tp;
+ int error;
+
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
+ if (error)
+ return error;
+
+ return __xfs_setfilesize(ip, tp, offset, size);
+}
+
+STATIC int
+xfs_setfilesize_ioend(
+ struct xfs_ioend *ioend,
+ int error)
+{
+ struct xfs_inode *ip = XFS_I(ioend->io_inode);
+ struct xfs_trans *tp = ioend->io_append_trans;
+
+ /*
+ * The transaction may have been allocated in the I/O submission thread,
+ * thus we need to mark ourselves as being in a transaction manually.
+ * Similarly for freeze protection.
+ */
+ current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
+ __sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS);
+
+ /* we abort the update if there was an IO error */
+ if (error) {
+ xfs_trans_cancel(tp);
+ return error;
+ }
+
+ return __xfs_setfilesize(ip, tp, ioend->io_offset, ioend->io_size);
+}
+
+/*
+ * IO write completion.
+ */
+STATIC void
+xfs_end_io(
+ struct work_struct *work)
+{
+ struct xfs_ioend *ioend =
+ container_of(work, struct xfs_ioend, io_work);
+ struct xfs_inode *ip = XFS_I(ioend->io_inode);
+ xfs_off_t offset = ioend->io_offset;
+ size_t size = ioend->io_size;
+ int error;
+
+ /*
+ * Just clean up the in-memory strutures if the fs has been shut down.
+ */
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+ error = -EIO;
+ goto done;
+ }
+
+ /*
+ * Clean up any COW blocks on an I/O error.
+ */
+ error = blk_status_to_errno(ioend->io_bio->bi_status);
+ if (unlikely(error)) {
+ switch (ioend->io_type) {
+ case XFS_IO_COW:
+ xfs_reflink_cancel_cow_range(ip, offset, size, true);
+ break;
+ }
+
+ goto done;
+ }
+
+ /*
+ * Success: commit the COW or unwritten blocks if needed.
+ */
+ switch (ioend->io_type) {
+ case XFS_IO_COW:
+ error = xfs_reflink_end_cow(ip, offset, size);
+ break;
+ case XFS_IO_UNWRITTEN:
+ /* writeback should never update isize */
+ error = xfs_iomap_write_unwritten(ip, offset, size, false);
+ break;
+ default:
+ ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_append_trans);
+ break;
+ }
+
+done:
+ if (ioend->io_append_trans)
+ error = xfs_setfilesize_ioend(ioend, error);
+ xfs_destroy_ioend(ioend, error);
+}
+
+STATIC void
+xfs_end_bio(
+ struct bio *bio)
+{
+ struct xfs_ioend *ioend = bio->bi_private;
+ struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount;
+
+ if (ioend->io_type == XFS_IO_UNWRITTEN || ioend->io_type == XFS_IO_COW)
+ queue_work(mp->m_unwritten_workqueue, &ioend->io_work);
+ else if (ioend->io_append_trans)
+ queue_work(mp->m_data_workqueue, &ioend->io_work);
+ else
+ xfs_destroy_ioend(ioend, blk_status_to_errno(bio->bi_status));
+}
+
+STATIC int
+xfs_map_blocks(
+ struct inode *inode,
+ loff_t offset,
+ struct xfs_bmbt_irec *imap,
+ int type)
+{
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ ssize_t count = i_blocksize(inode);
+ 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 -EIO;
+
+ ASSERT(type != XFS_IO_COW);
+ if (type == XFS_IO_UNWRITTEN)
+ bmapi_flags |= XFS_BMAPI_IGSTATE;
+
+ 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_super->s_maxbytes);
+
+ if ((xfs_ufsize_t)offset + count > mp->m_super->s_maxbytes)
+ count = mp->m_super->s_maxbytes - offset;
+ end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
+ offset_fsb = XFS_B_TO_FSBT(mp, offset);
+ error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
+ imap, &nimaps, bmapi_flags);
+ /*
+ * Truncate an overwrite extent if there's a pending CoW
+ * reservation before the end of this extent. This forces us
+ * to come back to writepage to take care of the CoW.
+ */
+ if (nimaps && type == XFS_IO_OVERWRITE)
+ xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb, imap);
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+
+ if (error)
+ return error;
+
+ if (type == XFS_IO_DELALLOC &&
+ (!nimaps || isnullstartblock(imap->br_startblock))) {
+ error = xfs_iomap_write_allocate(ip, XFS_DATA_FORK, offset,
+ imap);
+ if (!error)
+ trace_xfs_map_blocks_alloc(ip, offset, count, type, imap);
+ return error;
+ }
+
+#ifdef DEBUG
+ if (type == XFS_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 bool
+xfs_imap_valid(
+ struct inode *inode,
+ struct xfs_bmbt_irec *imap,
+ xfs_off_t offset)
+{
+ offset >>= inode->i_blkbits;
+
+ /*
+ * We have to make sure the cached mapping is within EOF to protect
+ * against eofblocks trimming on file release leaving us with a stale
+ * mapping. Otherwise, a page for a subsequent file extending buffered
+ * write could get picked up by this writeback cycle and written to the
+ * wrong blocks.
+ *
+ * Note that what we really want here is a generic mapping invalidation
+ * mechanism to protect us from arbitrary extent modifying contexts, not
+ * just eofblocks.
+ */
+ xfs_trim_extent_eof(imap, XFS_I(inode));
+
+ return offset >= imap->br_startoff &&
+ offset < imap->br_startoff + imap->br_blockcount;
+}
+
+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));
+
+ bh->b_end_io = NULL;
+ set_buffer_async_write(bh);
+ set_buffer_uptodate(bh);
+ clear_buffer_dirty(bh);
+}
+
+STATIC void
+xfs_start_page_writeback(
+ struct page *page,
+ int clear_dirty)
+{
+ ASSERT(PageLocked(page));
+ ASSERT(!PageWriteback(page));
+
+ /*
+ * if the page was not fully cleaned, we need to ensure that the higher
+ * layers come back to it correctly. That means we need to keep the page
+ * dirty, and for WB_SYNC_ALL writeback we need to ensure the
+ * PAGECACHE_TAG_TOWRITE index mark is not removed so another attempt to
+ * write this page in this writeback sweep will be made.
+ */
+ if (clear_dirty) {
+ clear_page_dirty_for_io(page);
+ set_page_writeback(page);
+ } else
+ set_page_writeback_keepwrite(page);
+
+ unlock_page(page);
+}
+
+static inline int xfs_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 the bio for an ioend. We are passed an ioend with a bio attached to
+ * it, and we submit that bio. The ioend may be used for multiple bio
+ * submissions, so we only want to allocate an append transaction for the ioend
+ * once. In the case of multiple bio submission, each bio will take an IO
+ * reference to the ioend to ensure that the ioend completion is only done once
+ * all bios have been submitted and the ioend is really done.
+ *
+ * If @fail is non-zero, it means that we have a situation where some part of
+ * the submission process has failed after we have marked paged for writeback
+ * and unlocked them. In this situation, we need to fail the bio and ioend
+ * rather than submit it to IO. This typically only happens on a filesystem
+ * shutdown.
+ */
+STATIC int
+xfs_submit_ioend(
+ struct writeback_control *wbc,
+ struct xfs_ioend *ioend,
+ int status)
+{
+ /* Convert CoW extents to regular */
+ if (!status && ioend->io_type == XFS_IO_COW) {
+ status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
+ ioend->io_offset, ioend->io_size);
+ }
+
+ /* Reserve log space if we might write beyond the on-disk inode size. */
+ if (!status &&
+ ioend->io_type != XFS_IO_UNWRITTEN &&
+ xfs_ioend_is_append(ioend) &&
+ !ioend->io_append_trans)
+ status = xfs_setfilesize_trans_alloc(ioend);
+
+ ioend->io_bio->bi_private = ioend;
+ ioend->io_bio->bi_end_io = xfs_end_bio;
+ ioend->io_bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
+
+ /*
+ * If we are failing the IO now, just mark the ioend with an
+ * error and finish it. This will run IO completion immediately
+ * as there is only one reference to the ioend at this point in
+ * time.
+ */
+ if (status) {
+ ioend->io_bio->bi_status = errno_to_blk_status(status);
+ bio_endio(ioend->io_bio);
+ return status;
+ }
+
+ ioend->io_bio->bi_write_hint = ioend->io_inode->i_write_hint;
+ submit_bio(ioend->io_bio);
+ return 0;
+}
+
+static void
+xfs_init_bio_from_bh(
+ struct bio *bio,
+ struct buffer_head *bh)
+{
+ bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
+ bio_set_dev(bio, bh->b_bdev);
+}
+
+static struct xfs_ioend *
+xfs_alloc_ioend(
+ struct inode *inode,
+ unsigned int type,
+ xfs_off_t offset,
+ struct buffer_head *bh)
+{
+ struct xfs_ioend *ioend;
+ struct bio *bio;
+
+ bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, xfs_ioend_bioset);
+ xfs_init_bio_from_bh(bio, bh);
+
+ ioend = container_of(bio, struct xfs_ioend, io_inline_bio);
+ INIT_LIST_HEAD(&ioend->io_list);
+ ioend->io_type = type;
+ ioend->io_inode = inode;
+ ioend->io_size = 0;
+ ioend->io_offset = offset;
+ INIT_WORK(&ioend->io_work, xfs_end_io);
+ ioend->io_append_trans = NULL;
+ ioend->io_bio = bio;
+ return ioend;
+}
+
+/*
+ * Allocate a new bio, and chain the old bio to the new one.
+ *
+ * Note that we have to do perform the chaining in this unintuitive order
+ * so that the bi_private linkage is set up in the right direction for the
+ * traversal in xfs_destroy_ioend().
+ */
+static void
+xfs_chain_bio(
+ struct xfs_ioend *ioend,
+ struct writeback_control *wbc,
+ struct buffer_head *bh)
+{
+ struct bio *new;
+
+ new = bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
+ xfs_init_bio_from_bh(new, bh);
+
+ bio_chain(ioend->io_bio, new);
+ bio_get(ioend->io_bio); /* for xfs_destroy_ioend */
+ ioend->io_bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
+ ioend->io_bio->bi_write_hint = ioend->io_inode->i_write_hint;
+ submit_bio(ioend->io_bio);
+ ioend->io_bio = new;
+}
+
+/*
+ * 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 the ioend we finished off so that the caller can submit it
+ * once it has finished processing the dirty page.
+ */
+STATIC void
+xfs_add_to_ioend(
+ struct inode *inode,
+ struct buffer_head *bh,
+ xfs_off_t offset,
+ struct xfs_writepage_ctx *wpc,
+ struct writeback_control *wbc,
+ struct list_head *iolist)
+{
+ if (!wpc->ioend || wpc->io_type != wpc->ioend->io_type ||
+ bh->b_blocknr != wpc->last_block + 1 ||
+ offset != wpc->ioend->io_offset + wpc->ioend->io_size) {
+ if (wpc->ioend)
+ list_add(&wpc->ioend->io_list, iolist);
+ wpc->ioend = xfs_alloc_ioend(inode, wpc->io_type, offset, bh);
+ }
+
+ /*
+ * If the buffer doesn't fit into the bio we need to allocate a new
+ * one. This shouldn't happen more than once for a given buffer.
+ */
+ while (xfs_bio_add_buffer(wpc->ioend->io_bio, bh) != bh->b_size)
+ xfs_chain_bio(wpc->ioend, wbc, bh);
+
+ wpc->ioend->io_size += bh->b_size;
+ wpc->last_block = bh->b_blocknr;
+ xfs_start_buffer_writeback(bh);
+}
+
+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 contains at least one buffer of a given @type.
+ * If @check_all_buffers is true, then we walk all the buffers in the page to
+ * try to find one of the type passed in. If it is not set, then the caller only
+ * needs to check the first buffer on the page for a match.
+ */
+STATIC bool
+xfs_check_page_type(
+ struct page *page,
+ unsigned int type,
+ bool check_all_buffers)
+{
+ struct buffer_head *bh;
+ struct buffer_head *head;
+
+ if (PageWriteback(page))
+ return false;
+ if (!page->mapping)
+ return false;
+ if (!page_has_buffers(page))
+ return false;
+
+ bh = head = page_buffers(page);
+ do {
+ if (buffer_unwritten(bh)) {
+ if (type == XFS_IO_UNWRITTEN)
+ return true;
+ } else if (buffer_delay(bh)) {
+ if (type == XFS_IO_DELALLOC)
+ return true;
+ } else if (buffer_dirty(bh) && buffer_mapped(bh)) {
+ if (type == XFS_IO_OVERWRITE)
+ return true;
+ }
+
+ /* If we are only checking the first buffer, we are done now. */
+ if (!check_all_buffers)
+ break;
+ } while ((bh = bh->b_this_page) != head);
+
+ return false;
+}
+
+STATIC void
+xfs_vm_invalidatepage(
+ struct page *page,
+ unsigned int offset,
+ unsigned int length)
+{
+ trace_xfs_invalidatepage(page->mapping->host, page, offset,
+ length);
+
+ /*
+ * If we are invalidating the entire page, clear the dirty state from it
+ * so that we can check for attempts to release dirty cached pages in
+ * xfs_vm_releasepage().
+ */
+ if (offset == 0 && length >= PAGE_SIZE)
+ cancel_dirty_page(page);
+ block_invalidatepage(page, offset, length);
+}
+
+/*
+ * 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_check_page_type(page, XFS_IO_DELALLOC, true))
+ 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 += i_blocksize(inode);
+
+ } while ((bh = bh->b_this_page) != head);
+
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+out_invalidate:
+ xfs_vm_invalidatepage(page, 0, PAGE_SIZE);
+ return;
+}
+
+static int
+xfs_map_cow(
+ struct xfs_writepage_ctx *wpc,
+ struct inode *inode,
+ loff_t offset,
+ unsigned int *new_type)
+{
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_bmbt_irec imap;
+ bool is_cow = false;
+ int error;
+
+ /*
+ * If we already have a valid COW mapping keep using it.
+ */
+ if (wpc->io_type == XFS_IO_COW) {
+ wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap, offset);
+ if (wpc->imap_valid) {
+ *new_type = XFS_IO_COW;
+ return 0;
+ }
+ }
+
+ /*
+ * Else we need to check if there is a COW mapping at this offset.
+ */
+ xfs_ilock(ip, XFS_ILOCK_SHARED);
+ is_cow = xfs_reflink_find_cow_mapping(ip, offset, &imap);
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+
+ if (!is_cow)
+ return 0;
+
+ /*
+ * And if the COW mapping has a delayed extent here we need to
+ * allocate real space for it now.
+ */
+ if (isnullstartblock(imap.br_startblock)) {
+ error = xfs_iomap_write_allocate(ip, XFS_COW_FORK, offset,
+ &imap);
+ if (error)
+ return error;
+ }
+
+ wpc->io_type = *new_type = XFS_IO_COW;
+ wpc->imap_valid = true;
+ wpc->imap = imap;
+ return 0;
+}
+
+/*
+ * We implement an immediate ioend submission policy here to avoid needing to
+ * chain multiple ioends and hence nest mempool allocations which can violate
+ * forward progress guarantees we need to provide. The current ioend we are
+ * adding buffers to is cached on the writepage context, and if the new buffer
+ * does not append to the cached ioend it will create a new ioend and cache that
+ * instead.
+ *
+ * If a new ioend is created and cached, the old ioend is returned and queued
+ * locally for submission once the entire page is processed or an error has been
+ * detected. While ioends are submitted immediately after they are completed,
+ * batching optimisations are provided by higher level block plugging.
+ *
+ * At the end of a writeback pass, there will be a cached ioend remaining on the
+ * writepage context that the caller will need to submit.
+ */
+static int
+xfs_writepage_map(
+ struct xfs_writepage_ctx *wpc,
+ struct writeback_control *wbc,
+ struct inode *inode,
+ struct page *page,
+ loff_t offset,
+ uint64_t end_offset)
+{
+ LIST_HEAD(submit_list);
+ struct xfs_ioend *ioend, *next;
+ struct buffer_head *bh, *head;
+ ssize_t len = i_blocksize(inode);
+ int error = 0;
+ int count = 0;
+ int uptodate = 1;
+ unsigned int new_type;
+
+ bh = head = page_buffers(page);
+ offset = page_offset(page);
+ do {
+ 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)) {
+ wpc->imap_valid = false;
+ continue;
+ }
+
+ if (buffer_unwritten(bh))
+ new_type = XFS_IO_UNWRITTEN;
+ else if (buffer_delay(bh))
+ new_type = XFS_IO_DELALLOC;
+ else if (buffer_uptodate(bh))
+ new_type = XFS_IO_OVERWRITE;
+ else {
+ if (PageUptodate(page))
+ ASSERT(buffer_mapped(bh));
+ /*
+ * This buffer is not uptodate and will not be
+ * written to disk. Ensure that we will put any
+ * subsequent writeable buffers into a new
+ * ioend.
+ */
+ wpc->imap_valid = false;
+ continue;
+ }
+
+ if (xfs_is_reflink_inode(XFS_I(inode))) {
+ error = xfs_map_cow(wpc, inode, offset, &new_type);
+ if (error)
+ goto out;
+ }
+
+ if (wpc->io_type != new_type) {
+ wpc->io_type = new_type;
+ wpc->imap_valid = false;
+ }
+
+ if (wpc->imap_valid)
+ wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
+ offset);
+ if (!wpc->imap_valid) {
+ error = xfs_map_blocks(inode, offset, &wpc->imap,
+ wpc->io_type);
+ if (error)
+ goto out;
+ wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
+ offset);
+ }
+ if (wpc->imap_valid) {
+ lock_buffer(bh);
+ if (wpc->io_type != XFS_IO_OVERWRITE)
+ xfs_map_at_offset(inode, bh, &wpc->imap, offset);
+ xfs_add_to_ioend(inode, bh, offset, wpc, wbc, &submit_list);
+ count++;
+ }
+
+ } while (offset += len, ((bh = bh->b_this_page) != head));
+
+ if (uptodate && bh == head)
+ SetPageUptodate(page);
+
+ ASSERT(wpc->ioend || list_empty(&submit_list));
+
+out:
+ /*
+ * On error, we have to fail the ioend here because we have locked
+ * buffers in the ioend. If we don't do this, we'll deadlock
+ * invalidating the page as that tries to lock the buffers on the page.
+ * Also, because we may have set pages under writeback, we have to make
+ * sure we run IO completion to mark the error state of the IO
+ * appropriately, so we can't cancel the ioend directly here. That means
+ * we have to mark this page as under writeback if we included any
+ * buffers from it in the ioend chain so that completion treats it
+ * correctly.
+ *
+ * If we didn't include the page in the ioend, the on error we can
+ * simply discard and unlock it as there are no other users of the page
+ * or it's buffers right now. The caller will still need to trigger
+ * submission of outstanding ioends on the writepage context so they are
+ * treated correctly on error.
+ */
+ if (count) {
+ xfs_start_page_writeback(page, !error);
+
+ /*
+ * Preserve the original error if there was one, otherwise catch
+ * submission errors here and propagate into subsequent ioend
+ * submissions.
+ */
+ list_for_each_entry_safe(ioend, next, &submit_list, io_list) {
+ int error2;
+
+ list_del_init(&ioend->io_list);
+ error2 = xfs_submit_ioend(wbc, ioend, error);
+ if (error2 && !error)
+ error = error2;
+ }
+ } else if (error) {
+ xfs_aops_discard_page(page);
+ ClearPageUptodate(page);
+ unlock_page(page);
+ } else {
+ /*
+ * We can end up here with no error and nothing to write if we
+ * race with a partial page truncate on a sub-page block sized
+ * filesystem. In that case we need to mark the page clean.
+ */
+ xfs_start_page_writeback(page, 1);
+ end_page_writeback(page);
+ }
+
+ mapping_set_error(page->mapping, error);
+ return error;
+}
+
+/*
+ * 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_do_writepage(
+ struct page *page,
+ struct writeback_control *wbc,
+ void *data)
+{
+ struct xfs_writepage_ctx *wpc = data;
+ struct inode *inode = page->mapping->host;
+ loff_t offset;
+ uint64_t end_offset;
+ pgoff_t end_index;
+
+ trace_xfs_writepage(inode, page, 0, 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 never happen except in the case of a VM regression so
+ * warn about it.
+ */
+ if (WARN_ON_ONCE((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_ONCE(current->flags & PF_MEMALLOC_NOFS))
+ goto redirty;
+
+ /*
+ * Is this page beyond the end of the file?
+ *
+ * The page index is less than the end_index, adjust the end_offset
+ * to the highest offset that this page should represent.
+ * -----------------------------------------------------
+ * | file mapping | <EOF> |
+ * -----------------------------------------------------
+ * | Page ... | Page N-2 | Page N-1 | Page N | |
+ * ^--------------------------------^----------|--------
+ * | desired writeback range | see else |
+ * ---------------------------------^------------------|
+ */
+ offset = i_size_read(inode);
+ end_index = offset >> PAGE_SHIFT;
+ if (page->index < end_index)
+ end_offset = (xfs_off_t)(page->index + 1) << PAGE_SHIFT;
+ else {
+ /*
+ * Check whether the page to write out is beyond or straddles
+ * i_size or not.
+ * -------------------------------------------------------
+ * | file mapping | <EOF> |
+ * -------------------------------------------------------
+ * | Page ... | Page N-2 | Page N-1 | Page N | Beyond |
+ * ^--------------------------------^-----------|---------
+ * | | Straddles |
+ * ---------------------------------^-----------|--------|
+ */
+ unsigned offset_into_page = offset & (PAGE_SIZE - 1);
+
+ /*
+ * Skip the page if it is fully outside i_size, e.g. due to a
+ * truncate operation that is in progress. We must redirty the
+ * page so that reclaim stops reclaiming it. Otherwise
+ * xfs_vm_releasepage() is called on it and gets confused.
+ *
+ * Note that the end_index is unsigned long, it would overflow
+ * if the given offset is greater than 16TB on 32-bit system
+ * and if we do check the page is fully outside i_size or not
+ * via "if (page->index >= end_index + 1)" as "end_index + 1"
+ * will be evaluated to 0. Hence this page will be redirtied
+ * and be written out repeatedly which would result in an
+ * infinite loop, the user program that perform this operation
+ * will hang. Instead, we can verify this situation by checking
+ * if the page to write is totally beyond the i_size or if it's
+ * offset is just equal to the EOF.
+ */
+ if (page->index > end_index ||
+ (page->index == end_index && offset_into_page == 0))
+ goto redirty;
+
+ /*
+ * The page straddles i_size. It must be zeroed out on each
+ * and every writepage invocation because it may be mmapped.
+ * "A file is mapped in multiples of the page size. For a file
+ * that is not a multiple of the page size, the remaining
+ * memory is zeroed when mapped, and writes to that region are
+ * not written out to the file."
+ */
+ zero_user_segment(page, offset_into_page, PAGE_SIZE);
+
+ /* Adjust the end_offset to the end of file */
+ end_offset = offset;
+ }
+
+ return xfs_writepage_map(wpc, wbc, inode, page, offset, end_offset);
+
+redirty:
+ redirty_page_for_writepage(wbc, page);
+ unlock_page(page);
+ return 0;
+}
+
+STATIC int
+xfs_vm_writepage(
+ struct page *page,
+ struct writeback_control *wbc)
+{
+ struct xfs_writepage_ctx wpc = {
+ .io_type = XFS_IO_INVALID,
+ };
+ int ret;
+
+ ret = xfs_do_writepage(page, wbc, &wpc);
+ if (wpc.ioend)
+ ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
+ return ret;
+}
+
+STATIC int
+xfs_vm_writepages(
+ struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct xfs_writepage_ctx wpc = {
+ .io_type = XFS_IO_INVALID,
+ };
+ int ret;
+
+ xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
+ if (dax_mapping(mapping))
+ return dax_writeback_mapping_range(mapping,
+ xfs_find_bdev_for_inode(mapping->host), wbc);
+
+ ret = write_cache_pages(mapping, wbc, xfs_do_writepage, &wpc);
+ if (wpc.ioend)
+ ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
+ return ret;
+}
+
+/*
+ * 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, 0);
+
+ /*
+ * mm accommodates an old ext3 case where clean pages might not have had
+ * the dirty bit cleared. Thus, it can send actual dirty pages to
+ * ->releasepage() via shrink_active_list(). Conversely,
+ * block_invalidatepage() can send pages that are still marked dirty but
+ * otherwise have invalidated buffers.
+ *
+ * We want to release the latter to avoid unnecessary buildup of the
+ * LRU, so xfs_vm_invalidatepage() clears the page dirty flag on pages
+ * that are entirely invalidated and need to be released. Hence the
+ * only time we should get dirty pages here is through
+ * shrink_active_list() and so we can simply skip those now.
+ *
+ * warn if we've left any lingering delalloc/unwritten buffers on clean
+ * or invalidated pages we are about to release.
+ */
+ if (PageDirty(page))
+ return 0;
+
+ xfs_count_page_state(page, &delalloc, &unwritten);
+
+ if (WARN_ON_ONCE(delalloc))
+ return 0;
+ if (WARN_ON_ONCE(unwritten))
+ return 0;
+
+ return try_to_free_buffers(page);
+}
+
+/*
+ * 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 the mapping spans EOF, then we have to break the mapping up as the mapping
+ * for blocks beyond EOF must be marked new so that sub block regions can be
+ * correctly zeroed. We can't do this for mappings within EOF unless the mapping
+ * was just allocated or is unwritten, otherwise the callers would overwrite
+ * existing data with zeros. Hence we have to split the mapping into a range up
+ * to and including EOF, and a second mapping for beyond EOF.
+ */
+static void
+xfs_map_trim_size(
+ struct inode *inode,
+ sector_t iblock,
+ struct buffer_head *bh_result,
+ struct xfs_bmbt_irec *imap,
+ xfs_off_t offset,
+ ssize_t size)
+{
+ 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 (offset < i_size_read(inode) &&
+ (xfs_ufsize_t)offset + mapping_size >= i_size_read(inode)) {
+ /* limit mapping to block that spans EOF */
+ mapping_size = roundup_64(i_size_read(inode) - offset,
+ i_blocksize(inode));
+ }
+ if (mapping_size > LONG_MAX)
+ mapping_size = LONG_MAX;
+
+ bh_result->b_size = mapping_size;
+}
+
+static int
+xfs_get_blocks(
+ struct inode *inode,
+ sector_t iblock,
+ struct buffer_head *bh_result,
+ int create)
+{
+ 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;
+
+ BUG_ON(create);
+
+ if (XFS_FORCED_SHUTDOWN(mp))
+ return -EIO;
+
+ offset = (xfs_off_t)iblock << inode->i_blkbits;
+ ASSERT(bh_result->b_size >= i_blocksize(inode));
+ size = bh_result->b_size;
+
+ if (offset >= i_size_read(inode))
+ return 0;
+
+ /*
+ * Direct I/O is usually done on preallocated files, so try getting
+ * a block mapping without an exclusive lock first.
+ */
+ lockmode = xfs_ilock_data_map_shared(ip);
+
+ ASSERT(offset <= mp->m_super->s_maxbytes);
+ if ((xfs_ufsize_t)offset + size > mp->m_super->s_maxbytes)
+ size = mp->m_super->s_maxbytes - offset;
+ end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + size);
+ offset_fsb = XFS_B_TO_FSBT(mp, offset);
+
+ error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
+ &imap, &nimaps, XFS_BMAPI_ENTIRE);
+ if (error)
+ goto out_unlock;
+
+ if (nimaps) {
+ trace_xfs_get_blocks_found(ip, offset, size,
+ imap.br_state == XFS_EXT_UNWRITTEN ?
+ XFS_IO_UNWRITTEN : XFS_IO_OVERWRITE, &imap);
+ xfs_iunlock(ip, lockmode);
+ } else {
+ trace_xfs_get_blocks_notfound(ip, offset, size);
+ goto out_unlock;
+ }
+
+ /* trim mapping down to size requested */
+ xfs_map_trim_size(inode, iblock, bh_result, &imap, offset, size);
+
+ /*
+ * For unwritten extents do not report a disk address in the buffered
+ * read case (treat as if we're reading into a hole).
+ */
+ if (xfs_bmap_is_real_extent(&imap))
+ xfs_map_buffer(inode, bh_result, &imap, offset);
+
+ /*
+ * 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);
+ return 0;
+
+out_unlock:
+ xfs_iunlock(ip, lockmode);
+ return error;
+}
+
+STATIC ssize_t
+xfs_vm_direct_IO(
+ struct kiocb *iocb,
+ struct iov_iter *iter)
+{
+ /*
+ * We just need the method present so that open/fcntl allow direct I/O.
+ */
+ return -EINVAL;
+}
+
+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));
+
+ /*
+ * The swap code (ab-)uses ->bmap to get a block mapping and then
+ * bypasseѕ the file system for actual I/O. We really can't allow
+ * that on reflinks inodes, so we have to skip out here. And yes,
+ * 0 is the magic code for a bmap error.
+ *
+ * Since we don't pass back blockdev info, we can't return bmap
+ * information for rt files either.
+ */
+ if (xfs_is_reflink_inode(ip) || XFS_IS_REALTIME_INODE(ip))
+ return 0;
+
+ filemap_write_and_wait(mapping);
+ return generic_block_bmap(mapping, block, xfs_get_blocks);
+}
+
+STATIC int
+xfs_vm_readpage(
+ struct file *unused,
+ struct page *page)
+{
+ trace_xfs_vm_readpage(page->mapping->host, 1);
+ 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)
+{
+ trace_xfs_vm_readpages(mapping->host, nr_pages);
+ return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
+}
+
+/*
+ * This is basically a copy of __set_page_dirty_buffers() with one
+ * small tweak: buffers beyond EOF do not get marked dirty. If we mark them
+ * dirty, we'll never be able to clean them because we don't write buffers
+ * beyond EOF, and that means we can't invalidate pages that span EOF
+ * that have been marked dirty. Further, the dirty state can leak into
+ * the file interior if the file is extended, resulting in all sorts of
+ * bad things happening as the state does not match the underlying data.
+ *
+ * XXX: this really indicates that bufferheads in XFS need to die. Warts like
+ * this only exist because of bufferheads and how the generic code manages them.
+ */
+STATIC int
+xfs_vm_set_page_dirty(
+ struct page *page)
+{
+ struct address_space *mapping = page->mapping;
+ struct inode *inode = mapping->host;
+ loff_t end_offset;
+ loff_t offset;
+ int newly_dirty;
+
+ if (unlikely(!mapping))
+ return !TestSetPageDirty(page);
+
+ end_offset = i_size_read(inode);
+ offset = page_offset(page);
+
+ spin_lock(&mapping->private_lock);
+ if (page_has_buffers(page)) {
+ struct buffer_head *head = page_buffers(page);
+ struct buffer_head *bh = head;
+
+ do {
+ if (offset < end_offset)
+ set_buffer_dirty(bh);
+ bh = bh->b_this_page;
+ offset += i_blocksize(inode);
+ } while (bh != head);
+ }
+ /*
+ * Lock out page->mem_cgroup migration to keep PageDirty
+ * synchronized with per-memcg dirty page counters.
+ */
+ lock_page_memcg(page);
+ newly_dirty = !TestSetPageDirty(page);
+ spin_unlock(&mapping->private_lock);
+
+ if (newly_dirty) {
+ /* sigh - __set_page_dirty() is static, so copy it here, too */
+ unsigned long flags;
+
+ spin_lock_irqsave(&mapping->tree_lock, flags);
+ if (page->mapping) { /* Race with truncate? */
+ WARN_ON_ONCE(!PageUptodate(page));
+ account_page_dirtied(page, mapping);
+ radix_tree_tag_set(&mapping->page_tree,
+ page_index(page), PAGECACHE_TAG_DIRTY);
+ }
+ spin_unlock_irqrestore(&mapping->tree_lock, flags);
+ }
+ unlock_page_memcg(page);
+ if (newly_dirty)
+ __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+ return newly_dirty;
+}
+
+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,
+ .set_page_dirty = xfs_vm_set_page_dirty,
+ .releasepage = xfs_vm_releasepage,
+ .invalidatepage = xfs_vm_invalidatepage,
+ .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,
+};