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2ba090d521
This adds ordering of the updates and makes sure we always see the if_seq update before the extent tree is modified. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
1042 lines
30 KiB
C
1042 lines
30 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2000-2005 Silicon Graphics, Inc.
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* Copyright (c) 2016-2018 Christoph Hellwig.
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* All Rights Reserved.
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*/
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#include "xfs.h"
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#include "xfs_shared.h"
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#include "xfs_format.h"
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#include "xfs_log_format.h"
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#include "xfs_trans_resv.h"
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#include "xfs_mount.h"
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#include "xfs_inode.h"
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#include "xfs_trans.h"
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#include "xfs_inode_item.h"
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#include "xfs_alloc.h"
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#include "xfs_error.h"
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#include "xfs_iomap.h"
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#include "xfs_trace.h"
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#include "xfs_bmap.h"
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#include "xfs_bmap_util.h"
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#include "xfs_bmap_btree.h"
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#include "xfs_reflink.h"
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#include <linux/writeback.h>
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/*
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* structure owned by writepages passed to individual writepage calls
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*/
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struct xfs_writepage_ctx {
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struct xfs_bmbt_irec imap;
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unsigned int io_type;
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unsigned int cow_seq;
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struct xfs_ioend *ioend;
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};
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struct block_device *
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xfs_find_bdev_for_inode(
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struct inode *inode)
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{
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struct xfs_inode *ip = XFS_I(inode);
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struct xfs_mount *mp = ip->i_mount;
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if (XFS_IS_REALTIME_INODE(ip))
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return mp->m_rtdev_targp->bt_bdev;
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else
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return mp->m_ddev_targp->bt_bdev;
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}
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struct dax_device *
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xfs_find_daxdev_for_inode(
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struct inode *inode)
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{
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struct xfs_inode *ip = XFS_I(inode);
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struct xfs_mount *mp = ip->i_mount;
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if (XFS_IS_REALTIME_INODE(ip))
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return mp->m_rtdev_targp->bt_daxdev;
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else
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return mp->m_ddev_targp->bt_daxdev;
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}
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static void
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xfs_finish_page_writeback(
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struct inode *inode,
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struct bio_vec *bvec,
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int error)
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{
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struct iomap_page *iop = to_iomap_page(bvec->bv_page);
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if (error) {
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SetPageError(bvec->bv_page);
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mapping_set_error(inode->i_mapping, -EIO);
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}
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ASSERT(iop || i_blocksize(inode) == PAGE_SIZE);
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ASSERT(!iop || atomic_read(&iop->write_count) > 0);
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if (!iop || atomic_dec_and_test(&iop->write_count))
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end_page_writeback(bvec->bv_page);
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}
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/*
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* We're now finished for good with this ioend structure. Update the page
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* state, release holds on bios, and finally free up memory. Do not use the
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* ioend after this.
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*/
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STATIC void
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xfs_destroy_ioend(
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struct xfs_ioend *ioend,
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int error)
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{
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struct inode *inode = ioend->io_inode;
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struct bio *bio = &ioend->io_inline_bio;
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struct bio *last = ioend->io_bio, *next;
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u64 start = bio->bi_iter.bi_sector;
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bool quiet = bio_flagged(bio, BIO_QUIET);
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for (bio = &ioend->io_inline_bio; bio; bio = next) {
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struct bio_vec *bvec;
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int i;
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/*
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* For the last bio, bi_private points to the ioend, so we
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* need to explicitly end the iteration here.
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*/
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if (bio == last)
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next = NULL;
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else
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next = bio->bi_private;
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/* walk each page on bio, ending page IO on them */
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bio_for_each_segment_all(bvec, bio, i)
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xfs_finish_page_writeback(inode, bvec, error);
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bio_put(bio);
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}
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if (unlikely(error && !quiet)) {
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xfs_err_ratelimited(XFS_I(inode)->i_mount,
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"writeback error on sector %llu", start);
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}
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}
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/*
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* Fast and loose check if this write could update the on-disk inode size.
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*/
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static inline bool xfs_ioend_is_append(struct xfs_ioend *ioend)
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{
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return ioend->io_offset + ioend->io_size >
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XFS_I(ioend->io_inode)->i_d.di_size;
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}
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STATIC int
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xfs_setfilesize_trans_alloc(
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struct xfs_ioend *ioend)
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{
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struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount;
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struct xfs_trans *tp;
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int error;
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error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0,
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XFS_TRANS_NOFS, &tp);
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if (error)
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return error;
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ioend->io_append_trans = tp;
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/*
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* We may pass freeze protection with a transaction. So tell lockdep
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* we released it.
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*/
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__sb_writers_release(ioend->io_inode->i_sb, SB_FREEZE_FS);
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/*
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* We hand off the transaction to the completion thread now, so
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* clear the flag here.
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*/
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current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
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return 0;
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}
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/*
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* Update on-disk file size now that data has been written to disk.
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*/
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STATIC int
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__xfs_setfilesize(
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struct xfs_inode *ip,
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struct xfs_trans *tp,
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xfs_off_t offset,
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size_t size)
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{
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xfs_fsize_t isize;
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xfs_ilock(ip, XFS_ILOCK_EXCL);
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isize = xfs_new_eof(ip, offset + size);
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if (!isize) {
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xfs_iunlock(ip, XFS_ILOCK_EXCL);
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xfs_trans_cancel(tp);
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return 0;
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}
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trace_xfs_setfilesize(ip, offset, size);
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ip->i_d.di_size = isize;
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xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
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xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
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return xfs_trans_commit(tp);
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}
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int
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xfs_setfilesize(
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struct xfs_inode *ip,
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xfs_off_t offset,
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size_t size)
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{
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struct xfs_mount *mp = ip->i_mount;
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struct xfs_trans *tp;
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int error;
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error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
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if (error)
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return error;
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return __xfs_setfilesize(ip, tp, offset, size);
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}
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STATIC int
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xfs_setfilesize_ioend(
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struct xfs_ioend *ioend,
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int error)
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{
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struct xfs_inode *ip = XFS_I(ioend->io_inode);
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struct xfs_trans *tp = ioend->io_append_trans;
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/*
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* The transaction may have been allocated in the I/O submission thread,
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* thus we need to mark ourselves as being in a transaction manually.
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* Similarly for freeze protection.
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*/
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current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
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__sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS);
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/* we abort the update if there was an IO error */
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if (error) {
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xfs_trans_cancel(tp);
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return error;
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}
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return __xfs_setfilesize(ip, tp, ioend->io_offset, ioend->io_size);
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}
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/*
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* IO write completion.
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*/
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STATIC void
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xfs_end_io(
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struct work_struct *work)
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{
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struct xfs_ioend *ioend =
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container_of(work, struct xfs_ioend, io_work);
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struct xfs_inode *ip = XFS_I(ioend->io_inode);
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xfs_off_t offset = ioend->io_offset;
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size_t size = ioend->io_size;
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int error;
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/*
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* Just clean up the in-memory strutures if the fs has been shut down.
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*/
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if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
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error = -EIO;
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goto done;
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}
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/*
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* Clean up any COW blocks on an I/O error.
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*/
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error = blk_status_to_errno(ioend->io_bio->bi_status);
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if (unlikely(error)) {
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switch (ioend->io_type) {
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case XFS_IO_COW:
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xfs_reflink_cancel_cow_range(ip, offset, size, true);
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break;
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}
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goto done;
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}
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/*
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* Success: commit the COW or unwritten blocks if needed.
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*/
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switch (ioend->io_type) {
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case XFS_IO_COW:
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error = xfs_reflink_end_cow(ip, offset, size);
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break;
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case XFS_IO_UNWRITTEN:
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/* writeback should never update isize */
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error = xfs_iomap_write_unwritten(ip, offset, size, false);
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break;
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default:
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ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_append_trans);
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break;
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}
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done:
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if (ioend->io_append_trans)
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error = xfs_setfilesize_ioend(ioend, error);
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xfs_destroy_ioend(ioend, error);
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}
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STATIC void
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xfs_end_bio(
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struct bio *bio)
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{
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struct xfs_ioend *ioend = bio->bi_private;
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struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount;
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if (ioend->io_type == XFS_IO_UNWRITTEN || ioend->io_type == XFS_IO_COW)
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queue_work(mp->m_unwritten_workqueue, &ioend->io_work);
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else if (ioend->io_append_trans)
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queue_work(mp->m_data_workqueue, &ioend->io_work);
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else
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xfs_destroy_ioend(ioend, blk_status_to_errno(bio->bi_status));
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}
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STATIC int
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xfs_map_blocks(
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struct xfs_writepage_ctx *wpc,
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struct inode *inode,
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loff_t offset)
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{
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struct xfs_inode *ip = XFS_I(inode);
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struct xfs_mount *mp = ip->i_mount;
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ssize_t count = i_blocksize(inode);
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xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset), end_fsb;
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xfs_fileoff_t cow_fsb = NULLFILEOFF;
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struct xfs_bmbt_irec imap;
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int whichfork = XFS_DATA_FORK;
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struct xfs_iext_cursor icur;
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bool imap_valid;
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int error = 0;
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/*
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* We have to make sure the cached mapping is within EOF to protect
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* against eofblocks trimming on file release leaving us with a stale
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* mapping. Otherwise, a page for a subsequent file extending buffered
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* write could get picked up by this writeback cycle and written to the
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* wrong blocks.
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*
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* Note that what we really want here is a generic mapping invalidation
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* mechanism to protect us from arbitrary extent modifying contexts, not
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* just eofblocks.
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*/
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xfs_trim_extent_eof(&wpc->imap, ip);
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/*
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* COW fork blocks can overlap data fork blocks even if the blocks
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* aren't shared. COW I/O always takes precedent, so we must always
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* check for overlap on reflink inodes unless the mapping is already a
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* COW one, or the COW fork hasn't changed from the last time we looked
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* at it.
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*
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* It's safe to check the COW fork if_seq here without the ILOCK because
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* we've indirectly protected against concurrent updates: writeback has
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* the page locked, which prevents concurrent invalidations by reflink
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* and directio and prevents concurrent buffered writes to the same
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* page. Changes to if_seq always happen under i_lock, which protects
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* against concurrent updates and provides a memory barrier on the way
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* out that ensures that we always see the current value.
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*/
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imap_valid = offset_fsb >= wpc->imap.br_startoff &&
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offset_fsb < wpc->imap.br_startoff + wpc->imap.br_blockcount;
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if (imap_valid &&
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(!xfs_inode_has_cow_data(ip) ||
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wpc->io_type == XFS_IO_COW ||
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wpc->cow_seq == READ_ONCE(ip->i_cowfp->if_seq)))
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return 0;
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if (XFS_FORCED_SHUTDOWN(mp))
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return -EIO;
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/*
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* If we don't have a valid map, now it's time to get a new one for this
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* offset. This will convert delayed allocations (including COW ones)
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* into real extents. If we return without a valid map, it means we
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* landed in a hole and we skip the block.
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*/
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xfs_ilock(ip, XFS_ILOCK_SHARED);
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ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
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(ip->i_df.if_flags & XFS_IFEXTENTS));
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ASSERT(offset <= mp->m_super->s_maxbytes);
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if (offset > mp->m_super->s_maxbytes - count)
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count = mp->m_super->s_maxbytes - offset;
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end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
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/*
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* Check if this is offset is covered by a COW extents, and if yes use
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* it directly instead of looking up anything in the data fork.
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*/
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if (xfs_inode_has_cow_data(ip) &&
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xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
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cow_fsb = imap.br_startoff;
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if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
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wpc->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
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xfs_iunlock(ip, XFS_ILOCK_SHARED);
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/*
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* Truncate can race with writeback since writeback doesn't
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* take the iolock and truncate decreases the file size before
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* it starts truncating the pages between new_size and old_size.
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* Therefore, we can end up in the situation where writeback
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* gets a CoW fork mapping but the truncate makes the mapping
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* invalid and we end up in here trying to get a new mapping.
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* bail out here so that we simply never get a valid mapping
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* and so we drop the write altogether. The page truncation
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* will kill the contents anyway.
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*/
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if (offset > i_size_read(inode)) {
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wpc->io_type = XFS_IO_HOLE;
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return 0;
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}
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whichfork = XFS_COW_FORK;
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wpc->io_type = XFS_IO_COW;
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goto allocate_blocks;
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}
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/*
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* Map valid and no COW extent in the way? We're done.
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*/
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if (imap_valid) {
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xfs_iunlock(ip, XFS_ILOCK_SHARED);
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return 0;
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}
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/*
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* If we don't have a valid map, now it's time to get a new one for this
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* offset. This will convert delayed allocations (including COW ones)
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* into real extents.
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*/
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if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap))
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imap.br_startoff = end_fsb; /* fake a hole past EOF */
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xfs_iunlock(ip, XFS_ILOCK_SHARED);
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if (imap.br_startoff > offset_fsb) {
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/* landed in a hole or beyond EOF */
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imap.br_blockcount = imap.br_startoff - offset_fsb;
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imap.br_startoff = offset_fsb;
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imap.br_startblock = HOLESTARTBLOCK;
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wpc->io_type = XFS_IO_HOLE;
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} else {
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/*
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* Truncate to the next COW extent if there is one. This is the
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* only opportunity to do this because we can skip COW fork
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* lookups for the subsequent blocks in the mapping; however,
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* the requirement to treat the COW range separately remains.
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*/
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if (cow_fsb != NULLFILEOFF &&
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cow_fsb < imap.br_startoff + imap.br_blockcount)
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imap.br_blockcount = cow_fsb - imap.br_startoff;
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if (isnullstartblock(imap.br_startblock)) {
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/* got a delalloc extent */
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wpc->io_type = XFS_IO_DELALLOC;
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goto allocate_blocks;
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}
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if (imap.br_state == XFS_EXT_UNWRITTEN)
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wpc->io_type = XFS_IO_UNWRITTEN;
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else
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wpc->io_type = XFS_IO_OVERWRITE;
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}
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wpc->imap = imap;
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trace_xfs_map_blocks_found(ip, offset, count, wpc->io_type, &imap);
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return 0;
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allocate_blocks:
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error = xfs_iomap_write_allocate(ip, whichfork, offset, &imap,
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&wpc->cow_seq);
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if (error)
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return error;
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ASSERT(whichfork == XFS_COW_FORK || cow_fsb == NULLFILEOFF ||
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imap.br_startoff + imap.br_blockcount <= cow_fsb);
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wpc->imap = imap;
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trace_xfs_map_blocks_alloc(ip, offset, count, wpc->io_type, &imap);
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return 0;
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}
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|
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/*
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* Submit the bio for an ioend. We are passed an ioend with a bio attached to
|
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* it, and we submit that bio. The ioend may be used for multiple bio
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* submissions, so we only want to allocate an append transaction for the ioend
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* once. In the case of multiple bio submission, each bio will take an IO
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* reference to the ioend to ensure that the ioend completion is only done once
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* all bios have been submitted and the ioend is really done.
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*
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* If @fail is non-zero, it means that we have a situation where some part of
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* 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) {
|
|
/*
|
|
* Yuk. This can do memory allocation, but is not a
|
|
* transactional operation so everything is done in GFP_KERNEL
|
|
* context. That can deadlock, because we hold pages in
|
|
* writeback state and GFP_KERNEL allocations can block on them.
|
|
* Hence we must operate in nofs conditions here.
|
|
*/
|
|
unsigned nofs_flag;
|
|
|
|
nofs_flag = memalloc_nofs_save();
|
|
status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
|
|
ioend->io_offset, ioend->io_size);
|
|
memalloc_nofs_restore(nofs_flag);
|
|
}
|
|
|
|
/* 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 struct xfs_ioend *
|
|
xfs_alloc_ioend(
|
|
struct inode *inode,
|
|
unsigned int type,
|
|
xfs_off_t offset,
|
|
struct block_device *bdev,
|
|
sector_t sector)
|
|
{
|
|
struct xfs_ioend *ioend;
|
|
struct bio *bio;
|
|
|
|
bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, &xfs_ioend_bioset);
|
|
bio_set_dev(bio, bdev);
|
|
bio->bi_iter.bi_sector = sector;
|
|
|
|
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 block_device *bdev,
|
|
sector_t sector)
|
|
{
|
|
struct bio *new;
|
|
|
|
new = bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
|
|
bio_set_dev(new, bdev);
|
|
new->bi_iter.bi_sector = sector;
|
|
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 have an existing ioend structure that we could append to
|
|
* first, otherwise finish off the current ioend and start another.
|
|
*/
|
|
STATIC void
|
|
xfs_add_to_ioend(
|
|
struct inode *inode,
|
|
xfs_off_t offset,
|
|
struct page *page,
|
|
struct iomap_page *iop,
|
|
struct xfs_writepage_ctx *wpc,
|
|
struct writeback_control *wbc,
|
|
struct list_head *iolist)
|
|
{
|
|
struct xfs_inode *ip = XFS_I(inode);
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
struct block_device *bdev = xfs_find_bdev_for_inode(inode);
|
|
unsigned len = i_blocksize(inode);
|
|
unsigned poff = offset & (PAGE_SIZE - 1);
|
|
sector_t sector;
|
|
|
|
sector = xfs_fsb_to_db(ip, wpc->imap.br_startblock) +
|
|
((offset - XFS_FSB_TO_B(mp, wpc->imap.br_startoff)) >> 9);
|
|
|
|
if (!wpc->ioend || wpc->io_type != wpc->ioend->io_type ||
|
|
sector != bio_end_sector(wpc->ioend->io_bio) ||
|
|
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,
|
|
bdev, sector);
|
|
}
|
|
|
|
if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff)) {
|
|
if (iop)
|
|
atomic_inc(&iop->write_count);
|
|
if (bio_full(wpc->ioend->io_bio))
|
|
xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
|
|
__bio_add_page(wpc->ioend->io_bio, page, len, poff);
|
|
}
|
|
|
|
wpc->ioend->io_size += len;
|
|
}
|
|
|
|
STATIC void
|
|
xfs_vm_invalidatepage(
|
|
struct page *page,
|
|
unsigned int offset,
|
|
unsigned int length)
|
|
{
|
|
trace_xfs_invalidatepage(page->mapping->host, page, offset, length);
|
|
iomap_invalidatepage(page, offset, length);
|
|
}
|
|
|
|
/*
|
|
* If the page has delalloc blocks 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 up a later direct I/O read operation on the same region.
|
|
*
|
|
* We prevent this by truncating away the delalloc regions on the page. 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).
|
|
*/
|
|
STATIC void
|
|
xfs_aops_discard_page(
|
|
struct page *page)
|
|
{
|
|
struct inode *inode = page->mapping->host;
|
|
struct xfs_inode *ip = XFS_I(inode);
|
|
struct xfs_mount *mp = ip->i_mount;
|
|
loff_t offset = page_offset(page);
|
|
xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, offset);
|
|
int error;
|
|
|
|
if (XFS_FORCED_SHUTDOWN(mp))
|
|
goto out_invalidate;
|
|
|
|
xfs_alert(mp,
|
|
"page discard on page "PTR_FMT", inode 0x%llx, offset %llu.",
|
|
page, ip->i_ino, offset);
|
|
|
|
error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
|
|
PAGE_SIZE / i_blocksize(inode));
|
|
if (error && !XFS_FORCED_SHUTDOWN(mp))
|
|
xfs_alert(mp, "page discard unable to remove delalloc mapping.");
|
|
out_invalidate:
|
|
xfs_vm_invalidatepage(page, 0, PAGE_SIZE);
|
|
}
|
|
|
|
/*
|
|
* 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 blocks to is cached on the writepage context, and if the new block
|
|
* 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,
|
|
uint64_t end_offset)
|
|
{
|
|
LIST_HEAD(submit_list);
|
|
struct iomap_page *iop = to_iomap_page(page);
|
|
unsigned len = i_blocksize(inode);
|
|
struct xfs_ioend *ioend, *next;
|
|
uint64_t file_offset; /* file offset of page */
|
|
int error = 0, count = 0, i;
|
|
|
|
ASSERT(iop || i_blocksize(inode) == PAGE_SIZE);
|
|
ASSERT(!iop || atomic_read(&iop->write_count) == 0);
|
|
|
|
/*
|
|
* Walk through the page to find areas to write back. If we run off the
|
|
* end of the current map or find the current map invalid, grab a new
|
|
* one.
|
|
*/
|
|
for (i = 0, file_offset = page_offset(page);
|
|
i < (PAGE_SIZE >> inode->i_blkbits) && file_offset < end_offset;
|
|
i++, file_offset += len) {
|
|
if (iop && !test_bit(i, iop->uptodate))
|
|
continue;
|
|
|
|
error = xfs_map_blocks(wpc, inode, file_offset);
|
|
if (error)
|
|
break;
|
|
if (wpc->io_type == XFS_IO_HOLE)
|
|
continue;
|
|
xfs_add_to_ioend(inode, file_offset, page, iop, wpc, wbc,
|
|
&submit_list);
|
|
count++;
|
|
}
|
|
|
|
ASSERT(wpc->ioend || list_empty(&submit_list));
|
|
ASSERT(PageLocked(page));
|
|
ASSERT(!PageWriteback(page));
|
|
|
|
/*
|
|
* On error, we have to fail the ioend here 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 blocks 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
|
|
* now. The caller will still need to trigger submission of outstanding
|
|
* ioends on the writepage context so they are treated correctly on
|
|
* error.
|
|
*/
|
|
if (unlikely(error)) {
|
|
if (!count) {
|
|
xfs_aops_discard_page(page);
|
|
ClearPageUptodate(page);
|
|
unlock_page(page);
|
|
goto done;
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
set_page_writeback_keepwrite(page);
|
|
} else {
|
|
clear_page_dirty_for_io(page);
|
|
set_page_writeback(page);
|
|
}
|
|
|
|
unlock_page(page);
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
/*
|
|
* We can end up here with no error and nothing to write only if we race
|
|
* with a partial page truncate on a sub-page block sized filesystem.
|
|
*/
|
|
if (!count)
|
|
end_page_writeback(page);
|
|
done:
|
|
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.
|
|
*/
|
|
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);
|
|
|
|
/*
|
|
* 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, 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);
|
|
ret = write_cache_pages(mapping, wbc, xfs_do_writepage, &wpc);
|
|
if (wpc.ioend)
|
|
ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
|
|
return ret;
|
|
}
|
|
|
|
STATIC int
|
|
xfs_dax_writepages(
|
|
struct address_space *mapping,
|
|
struct writeback_control *wbc)
|
|
{
|
|
xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
|
|
return dax_writeback_mapping_range(mapping,
|
|
xfs_find_bdev_for_inode(mapping->host), wbc);
|
|
}
|
|
|
|
STATIC int
|
|
xfs_vm_releasepage(
|
|
struct page *page,
|
|
gfp_t gfp_mask)
|
|
{
|
|
trace_xfs_releasepage(page->mapping->host, page, 0, 0);
|
|
return iomap_releasepage(page, gfp_mask);
|
|
}
|
|
|
|
STATIC sector_t
|
|
xfs_vm_bmap(
|
|
struct address_space *mapping,
|
|
sector_t block)
|
|
{
|
|
struct xfs_inode *ip = XFS_I(mapping->host);
|
|
|
|
trace_xfs_vm_bmap(ip);
|
|
|
|
/*
|
|
* The swap code (ab-)uses ->bmap to get a block mapping and then
|
|
* bypasses 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;
|
|
return iomap_bmap(mapping, block, &xfs_iomap_ops);
|
|
}
|
|
|
|
STATIC int
|
|
xfs_vm_readpage(
|
|
struct file *unused,
|
|
struct page *page)
|
|
{
|
|
trace_xfs_vm_readpage(page->mapping->host, 1);
|
|
return iomap_readpage(page, &xfs_iomap_ops);
|
|
}
|
|
|
|
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 iomap_readpages(mapping, pages, nr_pages, &xfs_iomap_ops);
|
|
}
|
|
|
|
static int
|
|
xfs_iomap_swapfile_activate(
|
|
struct swap_info_struct *sis,
|
|
struct file *swap_file,
|
|
sector_t *span)
|
|
{
|
|
sis->bdev = xfs_find_bdev_for_inode(file_inode(swap_file));
|
|
return iomap_swapfile_activate(sis, swap_file, span, &xfs_iomap_ops);
|
|
}
|
|
|
|
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 = iomap_set_page_dirty,
|
|
.releasepage = xfs_vm_releasepage,
|
|
.invalidatepage = xfs_vm_invalidatepage,
|
|
.bmap = xfs_vm_bmap,
|
|
.direct_IO = noop_direct_IO,
|
|
.migratepage = iomap_migrate_page,
|
|
.is_partially_uptodate = iomap_is_partially_uptodate,
|
|
.error_remove_page = generic_error_remove_page,
|
|
.swap_activate = xfs_iomap_swapfile_activate,
|
|
};
|
|
|
|
const struct address_space_operations xfs_dax_aops = {
|
|
.writepages = xfs_dax_writepages,
|
|
.direct_IO = noop_direct_IO,
|
|
.set_page_dirty = noop_set_page_dirty,
|
|
.invalidatepage = noop_invalidatepage,
|
|
.swap_activate = xfs_iomap_swapfile_activate,
|
|
};
|