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, 12 insertions, 18 deletions

diff --git a/fs/dax.c b/fs/dax.c
index 516f995a988c..38fae11ee419 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1507,7 +1507,7 @@ static int dax_zero_iter(struct iomap_iter *iter, bool *did_zero)
 
 	/* already zeroed?  we're done. */
 	if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN)
-		return iomap_iter_advance(iter, &length);
+		return iomap_iter_advance(iter, length);
 
 	/*
 	 * invalidate the pages whose sharing state is to be changed
@@ -1536,10 +1536,10 @@ static int dax_zero_iter(struct iomap_iter *iter, bool *did_zero)
 		if (ret < 0)
 			return ret;
 
-		ret = iomap_iter_advance(iter, &length);
+		ret = iomap_iter_advance(iter, length);
 		if (ret)
 			return ret;
-	} while (length > 0);
+	} while ((length = iomap_length(iter)) > 0);
 
 	if (did_zero)
 		*did_zero = true;
@@ -1597,7 +1597,7 @@ static int dax_iomap_iter(struct iomap_iter *iomi, struct iov_iter *iter)
 
 		if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) {
 			done = iov_iter_zero(min(length, end - pos), iter);
-			return iomap_iter_advance(iomi, &done);
+			return iomap_iter_advance(iomi, done);
 		}
 	}
 
@@ -1681,12 +1681,12 @@ static int dax_iomap_iter(struct iomap_iter *iomi, struct iov_iter *iter)
 			xfer = dax_copy_to_iter(dax_dev, pgoff, kaddr,
 					map_len, iter);
 
-		length = xfer;
-		ret = iomap_iter_advance(iomi, &length);
+		ret = iomap_iter_advance(iomi, xfer);
 		if (!ret && xfer == 0)
 			ret = -EFAULT;
 		if (xfer < map_len)
 			break;
+		length = iomap_length(iomi);
 	}
 	dax_read_unlock(id);
 
@@ -1919,10 +1919,8 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, unsigned long *pfnp,
 			ret |= VM_FAULT_MAJOR;
 		}
 
-		if (!(ret & VM_FAULT_ERROR)) {
-			u64 length = PAGE_SIZE;
-			iter.status = iomap_iter_advance(&iter, &length);
-		}
+		if (!(ret & VM_FAULT_ERROR))
+			iter.status = iomap_iter_advance(&iter, PAGE_SIZE);
 	}
 
 	if (iomap_errp)
@@ -2034,10 +2032,8 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, unsigned long *pfnp,
 			continue; /* actually breaks out of the loop */
 
 		ret = dax_fault_iter(vmf, &iter, pfnp, &xas, &entry, true);
-		if (ret != VM_FAULT_FALLBACK) {
-			u64 length = PMD_SIZE;
-			iter.status = iomap_iter_advance(&iter, &length);
-		}
+		if (ret != VM_FAULT_FALLBACK)
+			iter.status = iomap_iter_advance(&iter, PMD_SIZE);
 	}
 
 unlock_entry:
@@ -2163,7 +2159,6 @@ static int dax_range_compare_iter(struct iomap_iter *it_src,
 	const struct iomap *smap = &it_src->iomap;
 	const struct iomap *dmap = &it_dest->iomap;
 	loff_t pos1 = it_src->pos, pos2 = it_dest->pos;
-	u64 dest_len;
 	void *saddr, *daddr;
 	int id, ret;
 
@@ -2196,10 +2191,9 @@ static int dax_range_compare_iter(struct iomap_iter *it_src,
 	dax_read_unlock(id);
 
 advance:
-	dest_len = len;
-	ret = iomap_iter_advance(it_src, &len);
+	ret = iomap_iter_advance(it_src, len);
 	if (!ret)
-		ret = iomap_iter_advance(it_dest, &dest_len);
+		ret = iomap_iter_advance(it_dest, len);
 	return ret;
 
 out_unlock: