Merge tag 'vfs-6.19-rc1.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull iomap updates from Christian Brauner:
 "FUSE iomap Support for Buffered Reads:

    This adds iomap support for FUSE buffered reads and readahead. This
    enables granular uptodate tracking with large folios so only
    non-uptodate portions need to be read. Also fixes a race condition
    with large folios + writeback cache that could cause data corruption
    on partial writes followed by reads.

     - Refactored iomap read/readahead bio logic into helpers
     - Added caller-provided callbacks for read operations
     - Moved buffered IO bio logic into new file
     - FUSE now uses iomap for read_folio and readahead

  Zero Range Folio Batch Support:

    Add folio batch support for iomap_zero_range() to handle dirty
    folios over unwritten mappings. Fix raciness issues where dirty data
    could be lost during zero range operations.

     - filemap_get_folios_tag_range() helper for dirty folio lookup
     - Optional zero range dirty folio processing
     - XFS fills dirty folios on zero range of unwritten mappings
     - Removed old partial EOF zeroing optimization

  DIO Write Completions from Interrupt Context:

    Restore pre-iomap behavior where pure overwrite completions run
    inline rather than being deferred to workqueue. Reduces context
    switches for high-performance workloads like ScyllaDB.

     - Removed unused IOCB_DIO_CALLER_COMP code
     - Error completions always run in user context (fixes zonefs)
     - Reworked REQ_FUA selection logic
     - Inverted IOMAP_DIO_INLINE_COMP to IOMAP_DIO_OFFLOAD_COMP

  Buffered IO Cleanups:

    Some performance and code clarity improvements:

     - Replace manual bitmap scanning with find_next_bit()
     - Simplify read skip logic for writes
     - Optimize pending async writeback accounting
     - Better variable naming
     - Documentation for iomap_finish_folio_write() requirements

  Misaligned Vectors for Zoned XFS:

    Enables sub-block aligned vectors in XFS always-COW mode for zoned
    devices via new IOMAP_DIO_FSBLOCK_ALIGNED flag.

  Bug Fixes:

     - Allocate s_dio_done_wq for async reads (fixes syzbot report after
       error completion changes)
     - Fix iomap_read_end() for already uptodate folios (regression fix)"

* tag 'vfs-6.19-rc1.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (40 commits)
  iomap: allocate s_dio_done_wq for async reads as well
  iomap: fix iomap_read_end() for already uptodate folios
  iomap: invert the polarity of IOMAP_DIO_INLINE_COMP
  iomap: support write completions from interrupt context
  iomap: rework REQ_FUA selection
  iomap: always run error completions in user context
  fs, iomap: remove IOCB_DIO_CALLER_COMP
  iomap: use find_next_bit() for uptodate bitmap scanning
  iomap: use find_next_bit() for dirty bitmap scanning
  iomap: simplify when reads can be skipped for writes
  iomap: simplify ->read_folio_range() error handling for reads
  iomap: optimize pending async writeback accounting
  docs: document iomap writeback's iomap_finish_folio_write() requirement
  iomap: account for unaligned end offsets when truncating read range
  iomap: rename bytes_pending/bytes_accounted to bytes_submitted/bytes_not_submitted
  xfs: support sub-block aligned vectors in always COW mode
  iomap: add IOMAP_DIO_FSBLOCK_ALIGNED flag
  xfs: error tag to force zeroing on debug kernels
  iomap: remove old partial eof zeroing optimization
  xfs: fill dirty folios on zero range of unwritten mappings
  ...

1 files changed, 11 insertions, 9 deletions

diff --git a/fs/iomap/iter.c b/fs/iomap/iter.c
index cef77ca0c20b..8692e5e41c6d 100644
--- a/fs/iomap/iter.c
+++ b/fs/iomap/iter.c
@@ -8,22 +8,24 @@
 
 static inline void iomap_iter_reset_iomap(struct iomap_iter *iter)
 {
+	if (iter->fbatch) {
+		folio_batch_release(iter->fbatch);
+		kfree(iter->fbatch);
+		iter->fbatch = NULL;
+	}
+
 	iter->status = 0;
 	memset(&iter->iomap, 0, sizeof(iter->iomap));
 	memset(&iter->srcmap, 0, sizeof(iter->srcmap));
 }
 
-/*
- * Advance the current iterator position and output the length remaining for the
- * current mapping.
- */
-int iomap_iter_advance(struct iomap_iter *iter, u64 *count)
+/* Advance the current iterator position and decrement the remaining length */
+int iomap_iter_advance(struct iomap_iter *iter, u64 count)
 {
-	if (WARN_ON_ONCE(*count > iomap_length(iter)))
+	if (WARN_ON_ONCE(count > iomap_length(iter)))
 		return -EIO;
-	iter->pos += *count;
-	iter->len -= *count;
-	*count = iomap_length(iter);
+	iter->pos += count;
+	iter->len -= count;
 	return 0;
 }