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-rw-r--r--fs/xfs/xfs_aops.c698
1 files changed, 698 insertions, 0 deletions
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
new file mode 100644
index 000000000..8b6119776
--- /dev/null
+++ b/fs/xfs/xfs_aops.c
@@ -0,0 +1,698 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * Copyright (c) 2016-2025 Christoph Hellwig.
+ * All Rights Reserved.
+ */
+#include "xfs_platform.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_iomap.h"
+#include "xfs_trace.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_util.h"
+#include "xfs_reflink.h"
+#include "xfs_errortag.h"
+#include "xfs_error.h"
+#include "xfs_icache.h"
+#include "xfs_ioend.h"
+#include "xfs_zone_alloc.h"
+#include "xfs_rtgroup.h"
+#include <linux/bio-integrity.h>
+
+struct xfs_writepage_ctx {
+ struct iomap_writepage_ctx ctx;
+ unsigned int data_seq;
+ unsigned int cow_seq;
+};
+
+static inline struct xfs_writepage_ctx *
+XFS_WPC(struct iomap_writepage_ctx *ctx)
+{
+ return container_of(ctx, struct xfs_writepage_ctx, ctx);
+}
+
+/*
+ * Update on-disk file size now that data has been written to disk.
+ */
+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;
+ xfs_fsize_t isize;
+ int error;
+
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
+ if (error)
+ return error;
+
+ 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_disk_size = isize;
+ xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+ xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+ return xfs_trans_commit(tp);
+}
+
+/*
+ * We cannot cancel the ioend directly on error. We may have already set other
+ * pages under writeback and hence we have to run I/O completion to mark the
+ * error state of the pages under writeback appropriately.
+ *
+ * If the folio has delalloc blocks on it, the caller is asking us to punch them
+ * out. If we don't, we can leave a stale delalloc mapping covered by a clean
+ * page that needs to be dirtied again before the delalloc mapping can be
+ * converted. This stale delalloc mapping 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 folio. 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_discard_folio(
+ struct folio *folio,
+ loff_t pos)
+{
+ struct xfs_inode *ip = XFS_I(folio->mapping->host);
+ struct xfs_mount *mp = ip->i_mount;
+
+ if (xfs_is_shutdown(mp))
+ return;
+
+ xfs_alert_ratelimited(mp,
+ "page discard on page "PTR_FMT", inode 0x%llx, pos %llu.",
+ folio, I_INO(ip), pos);
+
+ /*
+ * The end of the punch range is always the offset of the first
+ * byte of the next folio. Hence the end offset is only dependent on the
+ * folio itself and not the start offset that is passed in.
+ */
+ xfs_bmap_punch_delalloc_range(ip, XFS_DATA_FORK, pos,
+ folio_next_pos(folio), NULL);
+}
+
+/*
+ * Fast revalidation of the cached writeback mapping. Return true if the current
+ * mapping is valid, false otherwise.
+ */
+static bool
+xfs_imap_valid(
+ struct iomap_writepage_ctx *wpc,
+ struct xfs_inode *ip,
+ loff_t offset)
+{
+ if (offset < wpc->iomap.offset ||
+ offset >= wpc->iomap.offset + wpc->iomap.length)
+ return false;
+ /*
+ * If this is a COW mapping, it is sufficient to check that the mapping
+ * covers the offset. Be careful to check this first because the caller
+ * can revalidate a COW mapping without updating the data seqno.
+ */
+ if (wpc->iomap.flags & IOMAP_F_SHARED)
+ return true;
+
+ /*
+ * This is not a COW mapping. Check the sequence number of the data fork
+ * because concurrent changes could have invalidated the extent. Check
+ * the COW fork because concurrent changes since the last time we
+ * checked (and found nothing at this offset) could have added
+ * overlapping blocks.
+ */
+ if (XFS_WPC(wpc)->data_seq != READ_ONCE(ip->i_df.if_seq)) {
+ trace_xfs_wb_data_iomap_invalid(ip, &wpc->iomap,
+ XFS_WPC(wpc)->data_seq, XFS_DATA_FORK);
+ return false;
+ }
+ if (xfs_inode_has_cow_data(ip) &&
+ XFS_WPC(wpc)->cow_seq != READ_ONCE(ip->i_cowfp->if_seq)) {
+ trace_xfs_wb_cow_iomap_invalid(ip, &wpc->iomap,
+ XFS_WPC(wpc)->cow_seq, XFS_COW_FORK);
+ return false;
+ }
+ return true;
+}
+
+static int
+xfs_map_blocks(
+ struct iomap_writepage_ctx *wpc,
+ loff_t offset,
+ unsigned int len)
+{
+ struct xfs_inode *ip = XFS_I(wpc->inode);
+ struct xfs_mount *mp = ip->i_mount;
+ ssize_t count = i_blocksize(wpc->inode);
+ xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
+ xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
+ xfs_fileoff_t cow_fsb;
+ int whichfork;
+ struct xfs_bmbt_irec imap;
+ struct xfs_iext_cursor icur;
+ int retries = 0;
+ int error = 0;
+ unsigned int *seq;
+
+ if (xfs_is_shutdown(mp))
+ return -EIO;
+
+ XFS_ERRORTAG_DELAY(mp, XFS_ERRTAG_WB_DELAY_MS);
+
+ /*
+ * COW fork blocks can overlap data fork blocks even if the blocks
+ * aren't shared. COW I/O always takes precedent, so we must always
+ * check for overlap on reflink inodes unless the mapping is already a
+ * COW one, or the COW fork hasn't changed from the last time we looked
+ * at it.
+ *
+ * It's safe to check the COW fork if_seq here without the ILOCK because
+ * we've indirectly protected against concurrent updates: writeback has
+ * the page locked, which prevents concurrent invalidations by reflink
+ * and directio and prevents concurrent buffered writes to the same
+ * page. Changes to if_seq always happen under i_lock, which protects
+ * against concurrent updates and provides a memory barrier on the way
+ * out that ensures that we always see the current value.
+ */
+ if (xfs_imap_valid(wpc, ip, offset))
+ return 0;
+
+ /*
+ * If we don't have a valid map, now it's time to get a new one for this
+ * offset. This will convert delayed allocations (including COW ones)
+ * into real extents. If we return without a valid map, it means we
+ * landed in a hole and we skip the block.
+ */
+retry:
+ cow_fsb = NULLFILEOFF;
+ whichfork = XFS_DATA_FORK;
+ xfs_ilock(ip, XFS_ILOCK_SHARED);
+ ASSERT(!xfs_need_iread_extents(&ip->i_df));
+
+ /*
+ * Check if this is offset is covered by a COW extents, and if yes use
+ * it directly instead of looking up anything in the data fork.
+ */
+ if (xfs_inode_has_cow_data(ip) &&
+ xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
+ cow_fsb = imap.br_startoff;
+ if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
+ XFS_WPC(wpc)->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+
+ whichfork = XFS_COW_FORK;
+ goto allocate_blocks;
+ }
+
+ /*
+ * No COW extent overlap. Revalidate now that we may have updated
+ * ->cow_seq. If the data mapping is still valid, we're done.
+ */
+ if (xfs_imap_valid(wpc, ip, offset)) {
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+ return 0;
+ }
+
+ /*
+ * If we don't have a valid map, now it's time to get a new one for this
+ * offset. This will convert delayed allocations (including COW ones)
+ * into real extents.
+ */
+ if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap))
+ imap.br_startoff = end_fsb; /* fake a hole past EOF */
+ XFS_WPC(wpc)->data_seq = READ_ONCE(ip->i_df.if_seq);
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+
+ /* landed in a hole or beyond EOF? */
+ if (imap.br_startoff > offset_fsb) {
+ imap.br_blockcount = imap.br_startoff - offset_fsb;
+ imap.br_startoff = offset_fsb;
+ imap.br_startblock = HOLESTARTBLOCK;
+ imap.br_state = XFS_EXT_NORM;
+ }
+
+ /*
+ * Truncate to the next COW extent if there is one. This is the only
+ * opportunity to do this because we can skip COW fork lookups for the
+ * subsequent blocks in the mapping; however, the requirement to treat
+ * the COW range separately remains.
+ */
+ if (cow_fsb != NULLFILEOFF &&
+ cow_fsb < imap.br_startoff + imap.br_blockcount)
+ imap.br_blockcount = cow_fsb - imap.br_startoff;
+
+ /* got a delalloc extent? */
+ if (imap.br_startblock != HOLESTARTBLOCK &&
+ isnullstartblock(imap.br_startblock))
+ goto allocate_blocks;
+
+ xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0, 0, XFS_WPC(wpc)->data_seq);
+ trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap);
+ return 0;
+allocate_blocks:
+ /*
+ * Convert a dellalloc extent to a real one. The current page is held
+ * locked so nothing could have removed the block backing offset_fsb,
+ * although it could have moved from the COW to the data fork by another
+ * thread.
+ */
+ if (whichfork == XFS_COW_FORK)
+ seq = &XFS_WPC(wpc)->cow_seq;
+ else
+ seq = &XFS_WPC(wpc)->data_seq;
+
+ error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
+ &wpc->iomap, seq);
+ if (error) {
+ /*
+ * If we failed to find the extent in the COW fork we might have
+ * raced with a COW to data fork conversion or truncate.
+ * Restart the lookup to catch the extent in the data fork for
+ * the former case, but prevent additional retries to avoid
+ * looping forever for the latter case.
+ */
+ if (error == -EAGAIN && whichfork == XFS_COW_FORK && !retries++)
+ goto retry;
+ ASSERT(error != -EAGAIN);
+ return error;
+ }
+
+ /*
+ * Due to merging the return real extent might be larger than the
+ * original delalloc one. Trim the return extent to the next COW
+ * boundary again to force a re-lookup.
+ */
+ if (whichfork != XFS_COW_FORK && cow_fsb != NULLFILEOFF) {
+ loff_t cow_offset = XFS_FSB_TO_B(mp, cow_fsb);
+
+ if (cow_offset < wpc->iomap.offset + wpc->iomap.length)
+ wpc->iomap.length = cow_offset - wpc->iomap.offset;
+ }
+
+ ASSERT(wpc->iomap.offset <= offset);
+ ASSERT(wpc->iomap.offset + wpc->iomap.length > offset);
+ trace_xfs_map_blocks_alloc(ip, offset, count, whichfork, &imap);
+ return 0;
+}
+
+static ssize_t
+xfs_writeback_range(
+ struct iomap_writepage_ctx *wpc,
+ struct folio *folio,
+ u64 offset,
+ unsigned int len,
+ u64 end_pos)
+{
+ ssize_t ret;
+
+ ret = xfs_map_blocks(wpc, offset, len);
+ if (!ret)
+ ret = iomap_add_to_ioend(wpc, folio, offset, end_pos, len);
+ if (ret < 0)
+ xfs_discard_folio(folio, offset);
+ return ret;
+}
+
+static bool
+xfs_ioend_needs_wq_completion(
+ struct iomap_ioend *ioend)
+{
+ /* Changing inode size requires a transaction. */
+ if (xfs_ioend_is_append(ioend))
+ return true;
+
+ /* Extent manipulation requires a transaction. */
+ if (ioend->io_flags & (IOMAP_IOEND_UNWRITTEN | IOMAP_IOEND_SHARED))
+ return true;
+
+ return false;
+}
+
+static int
+xfs_writeback_submit(
+ struct iomap_writepage_ctx *wpc,
+ int error)
+{
+ struct iomap_ioend *ioend = wpc->wb_ctx;
+
+ /*
+ * Convert CoW extents to regular.
+ *
+ * We can allocate memory here while doing writeback on behalf of memory
+ * reclaim. To avoid memory allocation deadlocks, set the task-wide
+ * nofs context.
+ */
+ if (!error && (ioend->io_flags & IOMAP_IOEND_SHARED)) {
+ unsigned int nofs_flag;
+
+ nofs_flag = memalloc_nofs_save();
+ error = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
+ ioend->io_offset, ioend->io_size);
+ memalloc_nofs_restore(nofs_flag);
+ }
+
+ /*
+ * Send ioends that might require a transaction to the completion wq,
+ * and disable the block layer task completion for them as there is no
+ * need to defer twice.
+ */
+ if (xfs_ioend_needs_wq_completion(ioend)) {
+ ioend->io_bio.bi_end_io = xfs_end_bio;
+ bio_clear_flag(&ioend->io_bio, BIO_COMPLETE_IN_TASK);
+ }
+
+ return iomap_ioend_writeback_submit(wpc, error);
+}
+
+static const struct iomap_writeback_ops xfs_writeback_ops = {
+ .writeback_range = xfs_writeback_range,
+ .writeback_submit = xfs_writeback_submit,
+};
+
+struct xfs_zoned_writepage_ctx {
+ struct iomap_writepage_ctx ctx;
+ struct xfs_open_zone *open_zone;
+};
+
+static inline struct xfs_zoned_writepage_ctx *
+XFS_ZWPC(struct iomap_writepage_ctx *ctx)
+{
+ return container_of(ctx, struct xfs_zoned_writepage_ctx, ctx);
+}
+
+static int
+xfs_zoned_map_blocks(
+ struct iomap_writepage_ctx *wpc,
+ loff_t offset,
+ unsigned int len)
+{
+ struct xfs_inode *ip = XFS_I(wpc->inode);
+ struct xfs_mount *mp = ip->i_mount;
+ xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
+ xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + len);
+ xfs_filblks_t count_fsb;
+ struct xfs_bmbt_irec imap, del;
+ struct xfs_iext_cursor icur;
+
+ if (xfs_is_shutdown(mp))
+ return -EIO;
+
+ XFS_ERRORTAG_DELAY(mp, XFS_ERRTAG_WB_DELAY_MS);
+
+ /*
+ * All dirty data must be covered by delalloc extents. But truncate can
+ * remove delalloc extents underneath us or reduce their size.
+ * Returning a hole tells iomap to not write back any data from this
+ * range, which is the right thing to do in that case.
+ *
+ * Otherwise just tell iomap to treat ranges previously covered by a
+ * delalloc extent as mapped. The actual block allocation will be done
+ * just before submitting the bio.
+ *
+ * This implies we never map outside folios that are locked or marked
+ * as under writeback, and thus there is no need check the fork sequence
+ * count here.
+ */
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
+ imap.br_startoff = end_fsb; /* fake a hole past EOF */
+ if (imap.br_startoff > offset_fsb) {
+ imap.br_blockcount = imap.br_startoff - offset_fsb;
+ imap.br_startoff = offset_fsb;
+ imap.br_startblock = HOLESTARTBLOCK;
+ imap.br_state = XFS_EXT_NORM;
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0, 0, 0);
+ return 0;
+ }
+ end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
+ count_fsb = end_fsb - offset_fsb;
+
+ del = imap;
+ xfs_trim_extent(&del, offset_fsb, count_fsb);
+ xfs_bmap_del_extent_delay(ip, XFS_COW_FORK, &icur, &imap, &del,
+ XFS_BMAPI_REMAP);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+ xfs_iomap_set_anon_write(ip, &wpc->iomap, offset,
+ XFS_FSB_TO_B(mp, count_fsb));
+ trace_xfs_zoned_map_blocks(ip, offset, wpc->iomap.length);
+ return 0;
+}
+
+static ssize_t
+xfs_zoned_writeback_range(
+ struct iomap_writepage_ctx *wpc,
+ struct folio *folio,
+ u64 offset,
+ unsigned int len,
+ u64 end_pos)
+{
+ ssize_t ret;
+
+ ret = xfs_zoned_map_blocks(wpc, offset, len);
+ if (!ret)
+ ret = iomap_add_to_ioend(wpc, folio, offset, end_pos, len);
+ if (ret < 0)
+ xfs_discard_folio(folio, offset);
+ return ret;
+}
+
+static int
+xfs_zoned_writeback_submit(
+ struct iomap_writepage_ctx *wpc,
+ int error)
+{
+ struct iomap_ioend *ioend = wpc->wb_ctx;
+
+ /*
+ * Defer all completions to our workqueue as all zoned writes require a
+ * transaction to be persisted. This also means we never need the block
+ * layer in-task completion for a task context.
+ */
+ ioend->io_bio.bi_end_io = xfs_end_bio;
+ bio_clear_flag(&ioend->io_bio, BIO_COMPLETE_IN_TASK);
+
+ if (error) {
+ ioend->io_bio.bi_status = errno_to_blk_status(error);
+ bio_endio(&ioend->io_bio);
+ return error;
+ }
+ if (wpc->iomap.flags & IOMAP_F_INTEGRITY)
+ fs_bio_integrity_generate(&ioend->io_bio);
+ xfs_zone_alloc_and_submit(ioend, &XFS_ZWPC(wpc)->open_zone);
+ return 0;
+}
+
+static const struct iomap_writeback_ops xfs_zoned_writeback_ops = {
+ .writeback_range = xfs_zoned_writeback_range,
+ .writeback_submit = xfs_zoned_writeback_submit,
+};
+
+STATIC int
+xfs_vm_writepages(
+ struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct xfs_inode *ip = XFS_I(mapping->host);
+
+ xfs_iflags_clear(ip, XFS_ITRUNCATED);
+
+ if (xfs_is_zoned_inode(ip)) {
+ struct xfs_zoned_writepage_ctx xc = {
+ .ctx = {
+ .inode = mapping->host,
+ .wbc = wbc,
+ .ops = &xfs_zoned_writeback_ops
+ },
+ };
+ int error;
+
+ error = iomap_writepages(&xc.ctx);
+ if (xc.open_zone)
+ xfs_open_zone_put(xc.open_zone);
+ return error;
+ } else {
+ struct xfs_writepage_ctx wpc = {
+ .ctx = {
+ .inode = mapping->host,
+ .wbc = wbc,
+ .ops = &xfs_writeback_ops
+ },
+ };
+
+ return iomap_writepages(&wpc.ctx);
+ }
+}
+
+STATIC int
+xfs_dax_writepages(
+ struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct xfs_inode *ip = XFS_I(mapping->host);
+
+ xfs_iflags_clear(ip, XFS_ITRUNCATED);
+ return dax_writeback_mapping_range(mapping,
+ xfs_inode_buftarg(ip)->bt_daxdev, wbc);
+}
+
+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_cow_inode(ip) || XFS_IS_REALTIME_INODE(ip))
+ return 0;
+ return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
+}
+
+static void
+xfs_bio_submit_read(
+ const struct iomap_iter *iter,
+ struct iomap_read_folio_ctx *ctx)
+{
+ struct bio *bio = ctx->read_ctx;
+
+ /* defer read completions to the ioend workqueue */
+ iomap_init_ioend(iter->inode, bio, ctx->read_ctx_file_offset, 0);
+ iomap_bio_submit_read_endio(iter, ctx, xfs_end_bio);
+}
+
+static const struct iomap_read_ops xfs_iomap_read_ops = {
+ .read_folio_range = iomap_bio_read_folio_range,
+ .submit_read = xfs_bio_submit_read,
+ .bio_set = &iomap_ioend_bioset,
+};
+
+static inline const struct iomap_read_ops *
+xfs_get_iomap_read_ops(
+ const struct address_space *mapping)
+{
+ struct xfs_inode *ip = XFS_I(mapping->host);
+
+ if (bdev_has_integrity_csum(xfs_inode_buftarg(ip)->bt_bdev))
+ return &xfs_iomap_read_ops;
+ return &iomap_bio_read_ops;
+}
+
+STATIC int
+xfs_vm_read_folio(
+ struct file *file,
+ struct folio *folio)
+{
+ struct iomap_read_folio_ctx ctx = { .cur_folio = folio };
+
+ ctx.ops = xfs_get_iomap_read_ops(folio->mapping);
+ iomap_read_folio(&xfs_read_iomap_ops, &ctx, NULL);
+ return 0;
+}
+
+STATIC void
+xfs_vm_readahead(
+ struct readahead_control *rac)
+{
+ struct iomap_read_folio_ctx ctx = { .rac = rac };
+
+ ctx.ops = xfs_get_iomap_read_ops(rac->mapping),
+ iomap_readahead(&xfs_read_iomap_ops, &ctx, NULL);
+}
+
+static int
+xfs_vm_swap_activate(
+ struct swap_info_struct *sis,
+ struct file *swap_file,
+ sector_t *span)
+{
+ struct xfs_inode *ip = XFS_I(file_inode(swap_file));
+
+ if (xfs_is_zoned_inode(ip))
+ return -EINVAL;
+
+ /*
+ * Swap file activation can race against concurrent shared extent
+ * removal in files that have been cloned. If this happens,
+ * iomap_swapfile_iter() can fail because it encountered a shared
+ * extent even though an operation is in progress to remove those
+ * shared extents.
+ *
+ * This race becomes problematic when we defer extent removal
+ * operations beyond the end of a syscall (i.e. use async background
+ * processing algorithms). Users think the extents are no longer
+ * shared, but iomap_swapfile_iter() still sees them as shared
+ * because the refcountbt entries for the extents being removed have
+ * not yet been updated. Hence the swapon call fails unexpectedly.
+ *
+ * The race condition is currently most obvious from the unlink()
+ * operation as extent removal is deferred until after the last
+ * reference to the inode goes away. We then process the extent
+ * removal asynchronously, hence triggers the "syscall completed but
+ * work not done" condition mentioned above. To close this race
+ * window, we need to flush any pending inodegc operations to ensure
+ * they have updated the refcountbt records before we try to map the
+ * swapfile.
+ */
+ xfs_inodegc_flush(ip->i_mount);
+
+ /*
+ * Direct the swap code to the correct block device when this file
+ * sits on the RT device.
+ */
+ sis->bdev = xfs_inode_buftarg(ip)->bt_bdev;
+
+ return iomap_swapfile_activate(sis, swap_file, span,
+ &xfs_read_iomap_ops);
+}
+
+const struct address_space_operations xfs_address_space_operations = {
+ .read_folio = xfs_vm_read_folio,
+ .readahead = xfs_vm_readahead,
+ .writepages = xfs_vm_writepages,
+ .dirty_folio = iomap_dirty_folio,
+ .release_folio = iomap_release_folio,
+ .invalidate_folio = iomap_invalidate_folio,
+ .bmap = xfs_vm_bmap,
+ .migrate_folio = filemap_migrate_folio,
+ .is_partially_uptodate = iomap_is_partially_uptodate,
+ .error_remove_folio = generic_error_remove_folio,
+ .swap_activate = xfs_vm_swap_activate,
+};
+
+const struct address_space_operations xfs_dax_aops = {
+ .writepages = xfs_dax_writepages,
+ .dirty_folio = noop_dirty_folio,
+ .swap_activate = xfs_vm_swap_activate,
+};