1 files changed, 634 insertions, 713 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 148a71b8b4d0..f102afc03359 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -20,6 +20,7 @@
 #include <linux/fs.h>
 #include <linux/filelock.h>
 #include <linux/splice.h>
+#include <linux/task_io_accounting_ops.h>
 
 static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
 			  unsigned int open_flags, int opcode,
@@ -50,13 +51,7 @@ static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
 	return fuse_simple_request(fm, &args);
 }
 
-struct fuse_release_args {
-	struct fuse_args args;
-	struct fuse_release_in inarg;
-	struct inode *inode;
-};
-
-struct fuse_file *fuse_file_alloc(struct fuse_mount *fm)
+struct fuse_file *fuse_file_alloc(struct fuse_mount *fm, bool release)
 {
 	struct fuse_file *ff;
 
@@ -65,15 +60,15 @@ struct fuse_file *fuse_file_alloc(struct fuse_mount *fm)
 		return NULL;
 
 	ff->fm = fm;
-	ff->release_args = kzalloc(sizeof(*ff->release_args),
-				   GFP_KERNEL_ACCOUNT);
-	if (!ff->release_args) {
-		kfree(ff);
-		return NULL;
+	if (release) {
+		ff->args = kzalloc(sizeof(*ff->args), GFP_KERNEL_ACCOUNT);
+		if (!ff->args) {
+			kfree(ff);
+			return NULL;
+		}
 	}
 
 	INIT_LIST_HEAD(&ff->write_entry);
-	mutex_init(&ff->readdir.lock);
 	refcount_set(&ff->count, 1);
 	RB_CLEAR_NODE(&ff->polled_node);
 	init_waitqueue_head(&ff->poll_wait);
@@ -85,8 +80,7 @@ struct fuse_file *fuse_file_alloc(struct fuse_mount *fm)
 
 void fuse_file_free(struct fuse_file *ff)
 {
-	kfree(ff->release_args);
-	mutex_destroy(&ff->readdir.lock);
+	kfree(ff->args);
 	kfree(ff);
 }
 
@@ -105,14 +99,17 @@ static void fuse_release_end(struct fuse_mount *fm, struct fuse_args *args,
 	kfree(ra);
 }
 
-static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir)
+static void fuse_file_put(struct fuse_file *ff, bool sync)
 {
 	if (refcount_dec_and_test(&ff->count)) {
-		struct fuse_args *args = &ff->release_args->args;
+		struct fuse_release_args *ra = &ff->args->release_args;
+		struct fuse_args *args = (ra ? &ra->args : NULL);
 
-		if (isdir ? ff->fm->fc->no_opendir : ff->fm->fc->no_open) {
-			/* Do nothing when client does not implement 'open' */
-			fuse_release_end(ff->fm, args, 0);
+		if (ra && ra->inode)
+			fuse_file_io_release(ff, ra->inode);
+
+		if (!args) {
+			/* Do nothing when server does not implement 'open' */
 		} else if (sync) {
 			fuse_simple_request(ff->fm, args);
 			fuse_release_end(ff->fm, args, 0);
@@ -132,27 +129,31 @@ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
 	struct fuse_conn *fc = fm->fc;
 	struct fuse_file *ff;
 	int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
+	bool open = isdir ? !fc->no_opendir : !fc->no_open;
 
-	ff = fuse_file_alloc(fm);
+	ff = fuse_file_alloc(fm, open);
 	if (!ff)
 		return ERR_PTR(-ENOMEM);
 
 	ff->fh = 0;
 	/* Default for no-open */
 	ff->open_flags = FOPEN_KEEP_CACHE | (isdir ? FOPEN_CACHE_DIR : 0);
-	if (isdir ? !fc->no_opendir : !fc->no_open) {
-		struct fuse_open_out outarg;
+	if (open) {
+		/* Store outarg for fuse_finish_open() */
+		struct fuse_open_out *outargp = &ff->args->open_outarg;
 		int err;
 
-		err = fuse_send_open(fm, nodeid, open_flags, opcode, &outarg);
+		err = fuse_send_open(fm, nodeid, open_flags, opcode, outargp);
 		if (!err) {
-			ff->fh = outarg.fh;
-			ff->open_flags = outarg.open_flags;
-
+			ff->fh = outargp->fh;
+			ff->open_flags = outargp->open_flags;
 		} else if (err != -ENOSYS) {
 			fuse_file_free(ff);
 			return ERR_PTR(err);
 		} else {
+			/* No release needed */
+			kfree(ff->args);
+			ff->args = NULL;
 			if (isdir)
 				fc->no_opendir = 1;
 			else
@@ -195,40 +196,50 @@ static void fuse_link_write_file(struct file *file)
 	spin_unlock(&fi->lock);
 }
 
-void fuse_finish_open(struct inode *inode, struct file *file)
+int fuse_finish_open(struct inode *inode, struct file *file)
 {
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = get_fuse_conn(inode);
+	int err;
+
+	err = fuse_file_io_open(file, inode);
+	if (err)
+		return err;
 
 	if (ff->open_flags & FOPEN_STREAM)
 		stream_open(inode, file);
 	else if (ff->open_flags & FOPEN_NONSEEKABLE)
 		nonseekable_open(inode, file);
 
-	if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
-		struct fuse_inode *fi = get_fuse_inode(inode);
-
-		spin_lock(&fi->lock);
-		fi->attr_version = atomic64_inc_return(&fc->attr_version);
-		i_size_write(inode, 0);
-		spin_unlock(&fi->lock);
-		file_update_time(file);
-		fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
-	}
 	if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
 		fuse_link_write_file(file);
+
+	return 0;
+}
+
+static void fuse_truncate_update_attr(struct inode *inode, struct file *file)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	struct fuse_inode *fi = get_fuse_inode(inode);
+
+	spin_lock(&fi->lock);
+	fi->attr_version = atomic64_inc_return(&fc->attr_version);
+	i_size_write(inode, 0);
+	spin_unlock(&fi->lock);
+	file_update_time(file);
+	fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
 }
 
-int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
+static int fuse_open(struct inode *inode, struct file *file)
 {
 	struct fuse_mount *fm = get_fuse_mount(inode);
+	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_conn *fc = fm->fc;
+	struct fuse_file *ff;
 	int err;
-	bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
-			  fc->atomic_o_trunc &&
-			  fc->writeback_cache;
-	bool dax_truncate = (file->f_flags & O_TRUNC) &&
-			  fc->atomic_o_trunc && FUSE_IS_DAX(inode);
+	bool is_truncate = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc;
+	bool is_wb_truncate = is_truncate && fc->writeback_cache;
+	bool dax_truncate = is_truncate && FUSE_IS_DAX(inode);
 
 	if (fuse_is_bad(inode))
 		return -EIO;
@@ -242,7 +253,7 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 
 	if (dax_truncate) {
 		filemap_invalidate_lock(inode->i_mapping);
-		err = fuse_dax_break_layouts(inode, 0, 0);
+		err = fuse_dax_break_layouts(inode, 0, -1);
 		if (err)
 			goto out_inode_unlock;
 	}
@@ -250,16 +261,20 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 	if (is_wb_truncate || dax_truncate)
 		fuse_set_nowrite(inode);
 
-	err = fuse_do_open(fm, get_node_id(inode), file, isdir);
-	if (!err)
-		fuse_finish_open(inode, file);
+	err = fuse_do_open(fm, get_node_id(inode), file, false);
+	if (!err) {
+		ff = file->private_data;
+		err = fuse_finish_open(inode, file);
+		if (err)
+			fuse_sync_release(fi, ff, file->f_flags);
+		else if (is_truncate)
+			fuse_truncate_update_attr(inode, file);
+	}
 
 	if (is_wb_truncate || dax_truncate)
 		fuse_release_nowrite(inode);
 	if (!err) {
-		struct fuse_file *ff = file->private_data;
-
-		if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC))
+		if (is_truncate)
 			truncate_pagecache(inode, 0);
 		else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
 			invalidate_inode_pages2(inode->i_mapping);
@@ -274,10 +289,13 @@ out_inode_unlock:
 }
 
 static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
-				 unsigned int flags, int opcode)
+				 unsigned int flags, int opcode, bool sync)
 {
 	struct fuse_conn *fc = ff->fm->fc;
-	struct fuse_release_args *ra = ff->release_args;
+	struct fuse_release_args *ra = &ff->args->release_args;
+
+	if (fuse_file_passthrough(ff))
+		fuse_passthrough_release(ff, fuse_inode_backing(fi));
 
 	/* Inode is NULL on error path of fuse_create_open() */
 	if (likely(fi)) {
@@ -292,6 +310,11 @@ static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
 
 	wake_up_interruptible_all(&ff->poll_wait);
 
+	if (!ra)
+		return;
+
+	/* ff->args was used for open outarg */
+	memset(ff->args, 0, sizeof(*ff->args));
 	ra->inarg.fh = ff->fh;
 	ra->inarg.flags = flags;
 	ra->args.in_numargs = 1;
@@ -301,23 +324,28 @@ static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
 	ra->args.nodeid = ff->nodeid;
 	ra->args.force = true;
 	ra->args.nocreds = true;
+
+	/*
+	 * Hold inode until release is finished.
+	 * From fuse_sync_release() the refcount is 1 and everything's
+	 * synchronous, so we are fine with not doing igrab() here.
+	 */
+	ra->inode = sync ? NULL : igrab(&fi->inode);
 }
 
 void fuse_file_release(struct inode *inode, struct fuse_file *ff,
 		       unsigned int open_flags, fl_owner_t id, bool isdir)
 {
 	struct fuse_inode *fi = get_fuse_inode(inode);
-	struct fuse_release_args *ra = ff->release_args;
+	struct fuse_release_args *ra = &ff->args->release_args;
 	int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
 
-	fuse_prepare_release(fi, ff, open_flags, opcode);
+	fuse_prepare_release(fi, ff, open_flags, opcode, false);
 
-	if (ff->flock) {
+	if (ra && ff->flock) {
 		ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
 		ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id);
 	}
-	/* Hold inode until release is finished */
-	ra->inode = igrab(inode);
 
 	/*
 	 * Normally this will send the RELEASE request, however if
@@ -328,7 +356,7 @@ void fuse_file_release(struct inode *inode, struct fuse_file *ff,
 	 * synchronous RELEASE is allowed (and desirable) in this case
 	 * because the server can be trusted not to screw up.
 	 */
-	fuse_file_put(ff, ff->fm->fc->destroy, isdir);
+	fuse_file_put(ff, ff->fm->fc->destroy);
 }
 
 void fuse_release_common(struct file *file, bool isdir)
@@ -337,11 +365,6 @@ void fuse_release_common(struct file *file, bool isdir)
 			  (fl_owner_t) file, isdir);
 }
 
-static int fuse_open(struct inode *inode, struct file *file)
-{
-	return fuse_open_common(inode, file, false);
-}
-
 static int fuse_release(struct inode *inode, struct file *file)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
@@ -363,12 +386,8 @@ void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
 		       unsigned int flags)
 {
 	WARN_ON(refcount_read(&ff->count) > 1);
-	fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
-	/*
-	 * iput(NULL) is a no-op and since the refcount is 1 and everything's
-	 * synchronous, we are fine with not doing igrab() here"
-	 */
-	fuse_file_put(ff, true, false);
+	fuse_prepare_release(fi, ff, flags, FUSE_RELEASE, true);
+	fuse_file_put(ff, true);
 }
 EXPORT_SYMBOL_GPL(fuse_sync_release);
 
@@ -396,74 +415,11 @@ u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 
 struct fuse_writepage_args {
 	struct fuse_io_args ia;
-	struct rb_node writepages_entry;
 	struct list_head queue_entry;
-	struct fuse_writepage_args *next;
 	struct inode *inode;
 	struct fuse_sync_bucket *bucket;
 };
 
-static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
-					    pgoff_t idx_from, pgoff_t idx_to)
-{
-	struct rb_node *n;
-
-	n = fi->writepages.rb_node;
-
-	while (n) {
-		struct fuse_writepage_args *wpa;
-		pgoff_t curr_index;
-
-		wpa = rb_entry(n, struct fuse_writepage_args, writepages_entry);
-		WARN_ON(get_fuse_inode(wpa->inode) != fi);
-		curr_index = wpa->ia.write.in.offset >> PAGE_SHIFT;
-		if (idx_from >= curr_index + wpa->ia.ap.num_pages)
-			n = n->rb_right;
-		else if (idx_to < curr_index)
-			n = n->rb_left;
-		else
-			return wpa;
-	}
-	return NULL;
-}
-
-/*
- * Check if any page in a range is under writeback
- *
- * This is currently done by walking the list of writepage requests
- * for the inode, which can be pretty inefficient.
- */
-static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
-				   pgoff_t idx_to)
-{
-	struct fuse_inode *fi = get_fuse_inode(inode);
-	bool found;
-
-	spin_lock(&fi->lock);
-	found = fuse_find_writeback(fi, idx_from, idx_to);
-	spin_unlock(&fi->lock);
-
-	return found;
-}
-
-static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
-{
-	return fuse_range_is_writeback(inode, index, index);
-}
-
-/*
- * Wait for page writeback to be completed.
- *
- * Since fuse doesn't rely on the VM writeback tracking, this has to
- * use some other means.
- */
-static void fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
-{
-	struct fuse_inode *fi = get_fuse_inode(inode);
-
-	wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
-}
-
 /*
  * Wait for all pending writepages on the inode to finish.
  *
@@ -498,10 +454,6 @@ static int fuse_flush(struct file *file, fl_owner_t id)
 	if (err)
 		return err;
 
-	inode_lock(inode);
-	fuse_sync_writes(inode);
-	inode_unlock(inode);
-
 	err = filemap_check_errors(file->f_mapping);
 	if (err)
 		return err;
@@ -626,16 +578,20 @@ void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
 	args->out_args[0].size = count;
 }
 
-static void fuse_release_user_pages(struct fuse_args_pages *ap,
+static void fuse_release_user_pages(struct fuse_args_pages *ap, ssize_t nres,
 				    bool should_dirty)
 {
 	unsigned int i;
 
-	for (i = 0; i < ap->num_pages; i++) {
+	for (i = 0; i < ap->num_folios; i++) {
 		if (should_dirty)
-			set_page_dirty_lock(ap->pages[i]);
-		put_page(ap->pages[i]);
+			folio_mark_dirty_lock(ap->folios[i]);
+		if (ap->args.is_pinned)
+			unpin_folio(ap->folios[i]);
 	}
+
+	if (nres > 0 && ap->args.invalidate_vmap)
+		invalidate_kernel_vmap_range(ap->args.vmap_base, nres);
 }
 
 static void fuse_io_release(struct kref *kref)
@@ -705,16 +661,16 @@ static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
 }
 
 static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io,
-					  unsigned int npages)
+						 unsigned int nfolios)
 {
 	struct fuse_io_args *ia;
 
 	ia = kzalloc(sizeof(*ia), GFP_KERNEL);
 	if (ia) {
 		ia->io = io;
-		ia->ap.pages = fuse_pages_alloc(npages, GFP_KERNEL,
-						&ia->ap.descs);
-		if (!ia->ap.pages) {
+		ia->ap.folios = fuse_folios_alloc(nfolios, GFP_KERNEL,
+						  &ia->ap.descs);
+		if (!ia->ap.folios) {
 			kfree(ia);
 			ia = NULL;
 		}
@@ -724,7 +680,7 @@ static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io,
 
 static void fuse_io_free(struct fuse_io_args *ia)
 {
-	kfree(ia->ap.pages);
+	kfree(ia->ap.folios);
 	kfree(ia);
 }
 
@@ -734,25 +690,29 @@ static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args,
 	struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
 	struct fuse_io_priv *io = ia->io;
 	ssize_t pos = -1;
-
-	fuse_release_user_pages(&ia->ap, io->should_dirty);
+	size_t nres;
 
 	if (err) {
 		/* Nothing */
 	} else if (io->write) {
 		if (ia->write.out.size > ia->write.in.size) {
 			err = -EIO;
-		} else if (ia->write.in.size != ia->write.out.size) {
-			pos = ia->write.in.offset - io->offset +
-				ia->write.out.size;
+		} else {
+			nres = ia->write.out.size;
+			if (ia->write.in.size != ia->write.out.size)
+				pos = ia->write.in.offset - io->offset +
+				      ia->write.out.size;
 		}
 	} else {
 		u32 outsize = args->out_args[0].size;
 
+		nres = outsize;
 		if (ia->read.in.size != outsize)
 			pos = ia->read.in.offset - io->offset + outsize;
 	}
 
+	fuse_release_user_pages(&ia->ap, err ?: nres, io->should_dirty);
+
 	fuse_aio_complete(io, err, pos);
 	fuse_io_free(ia);
 }
@@ -823,34 +783,27 @@ static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
 	 * reached the client fs yet.  So the hole is not present there.
 	 */
 	if (!fc->writeback_cache) {
-		loff_t pos = page_offset(ap->pages[0]) + num_read;
+		loff_t pos = folio_pos(ap->folios[0]) + num_read;
 		fuse_read_update_size(inode, pos, attr_ver);
 	}
 }
 
-static int fuse_do_readpage(struct file *file, struct page *page)
+static int fuse_do_readfolio(struct file *file, struct folio *folio)
 {
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio->mapping->host;
 	struct fuse_mount *fm = get_fuse_mount(inode);
-	loff_t pos = page_offset(page);
-	struct fuse_page_desc desc = { .length = PAGE_SIZE };
+	loff_t pos = folio_pos(folio);
+	struct fuse_folio_desc desc = { .length = folio_size(folio) };
 	struct fuse_io_args ia = {
 		.ap.args.page_zeroing = true,
 		.ap.args.out_pages = true,
-		.ap.num_pages = 1,
-		.ap.pages = &page,
+		.ap.num_folios = 1,
+		.ap.folios = &folio,
 		.ap.descs = &desc,
 	};
 	ssize_t res;
 	u64 attr_ver;
 
-	/*
-	 * Page writeback can extend beyond the lifetime of the
-	 * page-cache page, so make sure we read a properly synced
-	 * page.
-	 */
-	fuse_wait_on_page_writeback(inode, page->index);
-
 	attr_ver = fuse_get_attr_version(fm->fc);
 
 	/* Don't overflow end offset */
@@ -867,25 +820,24 @@ static int fuse_do_readpage(struct file *file, struct page *page)
 	if (res < desc.length)
 		fuse_short_read(inode, attr_ver, res, &ia.ap);
 
-	SetPageUptodate(page);
+	folio_mark_uptodate(folio);
 
 	return 0;
 }
 
 static int fuse_read_folio(struct file *file, struct folio *folio)
 {
-	struct page *page = &folio->page;
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio->mapping->host;
 	int err;
 
 	err = -EIO;
 	if (fuse_is_bad(inode))
 		goto out;
 
-	err = fuse_do_readpage(file, page);
+	err = fuse_do_readfolio(file, folio);
 	fuse_invalidate_atime(inode);
  out:
-	unlock_page(page);
+	folio_unlock(folio);
 	return err;
 }
 
@@ -899,8 +851,8 @@ static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
 	size_t num_read = args->out_args[0].size;
 	struct address_space *mapping = NULL;
 
-	for (i = 0; mapping == NULL && i < ap->num_pages; i++)
-		mapping = ap->pages[i]->mapping;
+	for (i = 0; mapping == NULL && i < ap->num_folios; i++)
+		mapping = ap->folios[i]->mapping;
 
 	if (mapping) {
 		struct inode *inode = mapping->host;
@@ -914,29 +866,23 @@ static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
 		fuse_invalidate_atime(inode);
 	}
 
-	for (i = 0; i < ap->num_pages; i++) {
-		struct page *page = ap->pages[i];
-
-		if (!err)
-			SetPageUptodate(page);
-		else
-			SetPageError(page);
-		unlock_page(page);
-		put_page(page);
+	for (i = 0; i < ap->num_folios; i++) {
+		folio_end_read(ap->folios[i], !err);
+		folio_put(ap->folios[i]);
 	}
 	if (ia->ff)
-		fuse_file_put(ia->ff, false, false);
+		fuse_file_put(ia->ff, false);
 
 	fuse_io_free(ia);
 }
 
-static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
+static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file,
+				unsigned int count)
 {
 	struct fuse_file *ff = file->private_data;
 	struct fuse_mount *fm = ff->fm;
 	struct fuse_args_pages *ap = &ia->ap;
-	loff_t pos = page_offset(ap->pages[0]);
-	size_t count = ap->num_pages << PAGE_SHIFT;
+	loff_t pos = folio_pos(ap->folios[0]);
 	ssize_t res;
 	int err;
 
@@ -947,7 +893,7 @@ static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
 	/* Don't overflow end offset */
 	if (pos + (count - 1) == LLONG_MAX) {
 		count--;
-		ap->descs[ap->num_pages - 1].length--;
+		ap->descs[ap->num_folios - 1].length--;
 	}
 	WARN_ON((loff_t) (pos + count) < 0);
 
@@ -970,7 +916,8 @@ static void fuse_readahead(struct readahead_control *rac)
 {
 	struct inode *inode = rac->mapping->host;
 	struct fuse_conn *fc = get_fuse_conn(inode);
-	unsigned int i, max_pages, nr_pages = 0;
+	unsigned int max_pages, nr_pages;
+	struct folio *folio = NULL;
 
 	if (fuse_is_bad(inode))
 		return;
@@ -978,9 +925,22 @@ static void fuse_readahead(struct readahead_control *rac)
 	max_pages = min_t(unsigned int, fc->max_pages,
 			fc->max_read / PAGE_SIZE);
 
-	for (;;) {
+	/*
+	 * This is only accurate the first time through, since readahead_folio()
+	 * doesn't update readahead_count() from the previous folio until the
+	 * next call.  Grab nr_pages here so we know how many pages we're going
+	 * to have to process.  This means that we will exit here with
+	 * readahead_count() == folio_nr_pages(last_folio), but we will have
+	 * consumed all of the folios, and read_pages() will call
+	 * readahead_folio() again which will clean up the rac.
+	 */
+	nr_pages = readahead_count(rac);
+
+	while (nr_pages) {
 		struct fuse_io_args *ia;
 		struct fuse_args_pages *ap;
+		unsigned cur_pages = min(max_pages, nr_pages);
+		unsigned int pages = 0;
 
 		if (fc->num_background >= fc->congestion_threshold &&
 		    rac->ra->async_size >= readahead_count(rac))
@@ -990,23 +950,46 @@ static void fuse_readahead(struct readahead_control *rac)
 			 */
 			break;
 
-		nr_pages = readahead_count(rac) - nr_pages;
-		if (nr_pages > max_pages)
-			nr_pages = max_pages;
-		if (nr_pages == 0)
-			break;
-		ia = fuse_io_alloc(NULL, nr_pages);
+		ia = fuse_io_alloc(NULL, cur_pages);
 		if (!ia)
-			return;
+			break;
 		ap = &ia->ap;
-		nr_pages = __readahead_batch(rac, ap->pages, nr_pages);
-		for (i = 0; i < nr_pages; i++) {
-			fuse_wait_on_page_writeback(inode,
-						    readahead_index(rac) + i);
-			ap->descs[i].length = PAGE_SIZE;
+
+		while (pages < cur_pages) {
+			unsigned int folio_pages;
+
+			/*
+			 * This returns a folio with a ref held on it.
+			 * The ref needs to be held until the request is
+			 * completed, since the splice case (see
+			 * fuse_try_move_page()) drops the ref after it's
+			 * replaced in the page cache.
+			 */
+			if (!folio)
+				folio =  __readahead_folio(rac);
+
+			folio_pages = folio_nr_pages(folio);
+			if (folio_pages > cur_pages - pages) {
+				/*
+				 * Large folios belonging to fuse will never
+				 * have more pages than max_pages.
+				 */
+				WARN_ON(!pages);
+				break;
+			}
+
+			ap->folios[ap->num_folios] = folio;
+			ap->descs[ap->num_folios].length = folio_size(folio);
+			ap->num_folios++;
+			pages += folio_pages;
+			folio = NULL;
 		}
-		ap->num_pages = nr_pages;
-		fuse_send_readpages(ia, rac->file);
+		fuse_send_readpages(ia, rac->file, pages << PAGE_SHIFT);
+		nr_pages -= pages;
+	}
+	if (folio) {
+		folio_end_read(folio, false);
+		folio_put(folio);
 	}
 }
 
@@ -1123,8 +1106,8 @@ static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
 	bool short_write;
 	int err;
 
-	for (i = 0; i < ap->num_pages; i++)
-		fuse_wait_on_page_writeback(inode, ap->pages[i]->index);
+	for (i = 0; i < ap->num_folios; i++)
+		folio_wait_writeback(ap->folios[i]);
 
 	fuse_write_args_fill(ia, ff, pos, count);
 	ia->write.in.flags = fuse_write_flags(iocb);
@@ -1138,24 +1121,24 @@ static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
 	short_write = ia->write.out.size < count;
 	offset = ap->descs[0].offset;
 	count = ia->write.out.size;
-	for (i = 0; i < ap->num_pages; i++) {
-		struct page *page = ap->pages[i];
+	for (i = 0; i < ap->num_folios; i++) {
+		struct folio *folio = ap->folios[i];
 
 		if (err) {
-			ClearPageUptodate(page);
+			folio_clear_uptodate(folio);
 		} else {
-			if (count >= PAGE_SIZE - offset)
-				count -= PAGE_SIZE - offset;
+			if (count >= folio_size(folio) - offset)
+				count -= folio_size(folio) - offset;
 			else {
 				if (short_write)
-					ClearPageUptodate(page);
+					folio_clear_uptodate(folio);
 				count = 0;
 			}
 			offset = 0;
 		}
-		if (ia->write.page_locked && (i == ap->num_pages - 1))
-			unlock_page(page);
-		put_page(page);
+		if (ia->write.folio_locked && (i == ap->num_folios - 1))
+			folio_unlock(folio);
+		folio_put(folio);
 	}
 
 	return err;
@@ -1170,67 +1153,80 @@ static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
 	struct fuse_conn *fc = get_fuse_conn(mapping->host);
 	unsigned offset = pos & (PAGE_SIZE - 1);
 	size_t count = 0;
-	int err;
+	unsigned int num;
+	int err = 0;
+
+	num = min(iov_iter_count(ii), fc->max_write);
+	num = min(num, max_pages << PAGE_SHIFT);
 
 	ap->args.in_pages = true;
 	ap->descs[0].offset = offset;
 
-	do {
+	while (num) {
 		size_t tmp;
-		struct page *page;
+		struct folio *folio;
 		pgoff_t index = pos >> PAGE_SHIFT;
-		size_t bytes = min_t(size_t, PAGE_SIZE - offset,
-				     iov_iter_count(ii));
-
-		bytes = min_t(size_t, bytes, fc->max_write - count);
+		unsigned int bytes;
+		unsigned int folio_offset;
 
  again:
-		err = -EFAULT;
-		if (fault_in_iov_iter_readable(ii, bytes))
-			break;
-
-		err = -ENOMEM;
-		page = grab_cache_page_write_begin(mapping, index);
-		if (!page)
+		folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
+					    mapping_gfp_mask(mapping));
+		if (IS_ERR(folio)) {
+			err = PTR_ERR(folio);
 			break;
+		}
 
 		if (mapping_writably_mapped(mapping))
-			flush_dcache_page(page);
+			flush_dcache_folio(folio);
+
+		folio_offset = ((index - folio->index) << PAGE_SHIFT) + offset;
+		bytes = min(folio_size(folio) - folio_offset, num);
 
-		tmp = copy_page_from_iter_atomic(page, offset, bytes, ii);
-		flush_dcache_page(page);
+		tmp = copy_folio_from_iter_atomic(folio, folio_offset, bytes, ii);
+		flush_dcache_folio(folio);
 
 		if (!tmp) {
-			unlock_page(page);
-			put_page(page);
+			folio_unlock(folio);
+			folio_put(folio);
+
+			/*
+			 * Ensure forward progress by faulting in
+			 * while not holding the folio lock:
+			 */
+			if (fault_in_iov_iter_readable(ii, bytes)) {
+				err = -EFAULT;
+				break;
+			}
+
 			goto again;
 		}
 
-		err = 0;
-		ap->pages[ap->num_pages] = page;
-		ap->descs[ap->num_pages].length = tmp;
-		ap->num_pages++;
+		ap->folios[ap->num_folios] = folio;
+		ap->descs[ap->num_folios].offset = folio_offset;
+		ap->descs[ap->num_folios].length = tmp;
+		ap->num_folios++;
 
 		count += tmp;
 		pos += tmp;
+		num -= tmp;
 		offset += tmp;
-		if (offset == PAGE_SIZE)
+		if (offset == folio_size(folio))
 			offset = 0;
 
-		/* If we copied full page, mark it uptodate */
-		if (tmp == PAGE_SIZE)
-			SetPageUptodate(page);
+		/* If we copied full folio, mark it uptodate */
+		if (tmp == folio_size(folio))
+			folio_mark_uptodate(folio);
 
-		if (PageUptodate(page)) {
-			unlock_page(page);
+		if (folio_test_uptodate(folio)) {
+			folio_unlock(folio);
 		} else {
-			ia->write.page_locked = true;
+			ia->write.folio_locked = true;
 			break;
 		}
-		if (!fc->big_writes)
+		if (!fc->big_writes || offset != 0)
 			break;
-	} while (iov_iter_count(ii) && count < fc->max_write &&
-		 ap->num_pages < max_pages && offset == 0);
+	}
 
 	return count > 0 ? count : err;
 }
@@ -1264,8 +1260,8 @@ static ssize_t fuse_perform_write(struct kiocb *iocb, struct iov_iter *ii)
 		unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
 						      fc->max_pages);
 
-		ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs);
-		if (!ap->pages) {
+		ap->folios = fuse_folios_alloc(nr_pages, GFP_KERNEL, &ap->descs);
+		if (!ap->folios) {
 			err = -ENOMEM;
 			break;
 		}
@@ -1287,7 +1283,7 @@ static ssize_t fuse_perform_write(struct kiocb *iocb, struct iov_iter *ii)
 					err = -EIO;
 			}
 		}
-		kfree(ap->pages);
+		kfree(ap->folios);
 	} while (!err && iov_iter_count(ii));
 
 	fuse_write_update_attr(inode, pos, res);
@@ -1299,13 +1295,94 @@ static ssize_t fuse_perform_write(struct kiocb *iocb, struct iov_iter *ii)
 	return res;
 }
 
+static bool fuse_io_past_eof(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode);
+}
+
+/*
+ * @return true if an exclusive lock for direct IO writes is needed
+ */
+static bool fuse_dio_wr_exclusive_lock(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct fuse_file *ff = file->private_data;
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct fuse_inode *fi = get_fuse_inode(inode);
+
+	/* Server side has to advise that it supports parallel dio writes. */
+	if (!(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES))
+		return true;
+
+	/*
+	 * Append will need to know the eventual EOF - always needs an
+	 * exclusive lock.
+	 */
+	if (iocb->ki_flags & IOCB_APPEND)
+		return true;
+
+	/* shared locks are not allowed with parallel page cache IO */
+	if (test_bit(FUSE_I_CACHE_IO_MODE, &fi->state))
+		return true;
+
+	/* Parallel dio beyond EOF is not supported, at least for now. */
+	if (fuse_io_past_eof(iocb, from))
+		return true;
+
+	return false;
+}
+
+static void fuse_dio_lock(struct kiocb *iocb, struct iov_iter *from,
+			  bool *exclusive)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct fuse_inode *fi = get_fuse_inode(inode);
+
+	*exclusive = fuse_dio_wr_exclusive_lock(iocb, from);
+	if (*exclusive) {
+		inode_lock(inode);
+	} else {
+		inode_lock_shared(inode);
+		/*
+		 * New parallal dio allowed only if inode is not in caching
+		 * mode and denies new opens in caching mode. This check
+		 * should be performed only after taking shared inode lock.
+		 * Previous past eof check was without inode lock and might
+		 * have raced, so check it again.
+		 */
+		if (fuse_io_past_eof(iocb, from) ||
+		    fuse_inode_uncached_io_start(fi, NULL) != 0) {
+			inode_unlock_shared(inode);
+			inode_lock(inode);
+			*exclusive = true;
+		}
+	}
+}
+
+static void fuse_dio_unlock(struct kiocb *iocb, bool exclusive)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct fuse_inode *fi = get_fuse_inode(inode);
+
+	if (exclusive) {
+		inode_unlock(inode);
+	} else {
+		/* Allow opens in caching mode after last parallel dio end */
+		fuse_inode_uncached_io_end(fi);
+		inode_unlock_shared(inode);
+	}
+}
+
 static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
+	struct mnt_idmap *idmap = file_mnt_idmap(file);
 	struct address_space *mapping = file->f_mapping;
 	ssize_t written = 0;
 	struct inode *inode = mapping->host;
-	ssize_t err;
+	ssize_t err, count;
 	struct fuse_conn *fc = get_fuse_conn(inode);
 
 	if (fc->writeback_cache) {
@@ -1316,7 +1393,7 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
 			return err;
 
 		if (fc->handle_killpriv_v2 &&
-		    setattr_should_drop_suidgid(&nop_mnt_idmap,
+		    setattr_should_drop_suidgid(idmap,
 						file_inode(file))) {
 			goto writethrough;
 		}
@@ -1327,15 +1404,13 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
 writethrough:
 	inode_lock(inode);
 
-	err = generic_write_checks(iocb, from);
+	err = count = generic_write_checks(iocb, from);
 	if (err <= 0)
 		goto out;
 
-	err = file_remove_privs(file);
-	if (err)
-		goto out;
+	task_io_account_write(count);
 
-	err = file_update_time(file);
+	err = kiocb_modified(iocb);
 	if (err)
 		goto out;
 
@@ -1369,55 +1444,97 @@ static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
 
 static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
 			       size_t *nbytesp, int write,
-			       unsigned int max_pages)
+			       unsigned int max_pages,
+			       bool use_pages_for_kvec_io)
 {
+	bool flush_or_invalidate = false;
+	unsigned int nr_pages = 0;
 	size_t nbytes = 0;  /* # bytes already packed in req */
 	ssize_t ret = 0;
 
-	/* Special case for kernel I/O: can copy directly into the buffer */
+	/* Special case for kernel I/O: can copy directly into the buffer.
+	 * However if the implementation of fuse_conn requires pages instead of
+	 * pointer (e.g., virtio-fs), use iov_iter_extract_pages() instead.
+	 */
 	if (iov_iter_is_kvec(ii)) {
-		unsigned long user_addr = fuse_get_user_addr(ii);
-		size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
+		void *user_addr = (void *)fuse_get_user_addr(ii);
 
-		if (write)
-			ap->args.in_args[1].value = (void *) user_addr;
-		else
-			ap->args.out_args[0].value = (void *) user_addr;
+		if (!use_pages_for_kvec_io) {
+			size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
 
-		iov_iter_advance(ii, frag_size);
-		*nbytesp = frag_size;
-		return 0;
+			if (write)
+				ap->args.in_args[1].value = user_addr;
+			else
+				ap->args.out_args[0].value = user_addr;
+
+			iov_iter_advance(ii, frag_size);
+			*nbytesp = frag_size;
+			return 0;
+		}
+
+		if (is_vmalloc_addr(user_addr)) {
+			ap->args.vmap_base = user_addr;
+			flush_or_invalidate = true;
+		}
+	}
+
+	/*
+	 * Until there is support for iov_iter_extract_folios(), we have to
+	 * manually extract pages using iov_iter_extract_pages() and then
+	 * copy that to a folios array.
+	 */
+	struct page **pages = kzalloc(max_pages * sizeof(struct page *),
+				      GFP_KERNEL);
+	if (!pages) {
+		ret = -ENOMEM;
+		goto out;
 	}
 
-	while (nbytes < *nbytesp && ap->num_pages < max_pages) {
-		unsigned npages;
+	while (nbytes < *nbytesp && nr_pages < max_pages) {
+		unsigned nfolios, i;
 		size_t start;
-		ret = iov_iter_get_pages2(ii, &ap->pages[ap->num_pages],
-					*nbytesp - nbytes,
-					max_pages - ap->num_pages,
-					&start);
+
+		ret = iov_iter_extract_pages(ii, &pages,
+					     *nbytesp - nbytes,
+					     max_pages - nr_pages,
+					     0, &start);
 		if (ret < 0)
 			break;
 
 		nbytes += ret;
 
-		ret += start;
-		npages = DIV_ROUND_UP(ret, PAGE_SIZE);
+		nfolios = DIV_ROUND_UP(ret + start, PAGE_SIZE);
+
+		for (i = 0; i < nfolios; i++) {
+			struct folio *folio = page_folio(pages[i]);
+			unsigned int offset = start +
+				(folio_page_idx(folio, pages[i]) << PAGE_SHIFT);
+			unsigned int len = min_t(unsigned int, ret, PAGE_SIZE - start);
 
-		ap->descs[ap->num_pages].offset = start;
-		fuse_page_descs_length_init(ap->descs, ap->num_pages, npages);
+			ap->descs[ap->num_folios].offset = offset;
+			ap->descs[ap->num_folios].length = len;
+			ap->folios[ap->num_folios] = folio;
+			start = 0;
+			ret -= len;
+			ap->num_folios++;
+		}
 
-		ap->num_pages += npages;
-		ap->descs[ap->num_pages - 1].length -=
-			(PAGE_SIZE - ret) & (PAGE_SIZE - 1);
+		nr_pages += nfolios;
 	}
+	kfree(pages);
+
+	if (write && flush_or_invalidate)
+		flush_kernel_vmap_range(ap->args.vmap_base, nbytes);
 
+	ap->args.invalidate_vmap = !write && flush_or_invalidate;
+	ap->args.is_pinned = iov_iter_extract_will_pin(ii);
 	ap->args.user_pages = true;
 	if (write)
 		ap->args.in_pages = true;
 	else
 		ap->args.out_pages = true;
 
+out:
 	*nbytesp = nbytes;
 
 	return ret < 0 ? ret : 0;
@@ -1456,7 +1573,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
 			return res;
 		}
 	}
-	if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
+	if (!cuse && filemap_range_has_writeback(mapping, pos, (pos + count - 1))) {
 		if (!write)
 			inode_lock(inode);
 		fuse_sync_writes(inode);
@@ -1479,7 +1596,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
 		size_t nbytes = min(count, nmax);
 
 		err = fuse_get_user_pages(&ia->ap, iter, &nbytes, write,
-					  max_pages);
+					  max_pages, fc->use_pages_for_kvec_io);
 		if (err && !nbytes)
 			break;
 
@@ -1493,7 +1610,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
 		}
 
 		if (!io->async || nres < 0) {
-			fuse_release_user_pages(&ia->ap, io->should_dirty);
+			fuse_release_user_pages(&ia->ap, nres, io->should_dirty);
 			fuse_io_free(ia);
 		}
 		ia = NULL;
@@ -1547,7 +1664,7 @@ static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
 	ssize_t res;
 
-	if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
+	if (!is_sync_kiocb(iocb)) {
 		res = fuse_direct_IO(iocb, to);
 	} else {
 		struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
@@ -1558,63 +1675,27 @@ static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	return res;
 }
 
-static bool fuse_direct_write_extending_i_size(struct kiocb *iocb,
-					       struct iov_iter *iter)
-{
-	struct inode *inode = file_inode(iocb->ki_filp);
-
-	return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode);
-}
-
 static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct inode *inode = file_inode(iocb->ki_filp);
-	struct file *file = iocb->ki_filp;
-	struct fuse_file *ff = file->private_data;
-	struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
 	ssize_t res;
-	bool exclusive_lock =
-		!(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES) ||
-		get_fuse_conn(inode)->direct_io_allow_mmap ||
-		iocb->ki_flags & IOCB_APPEND ||
-		fuse_direct_write_extending_i_size(iocb, from);
-
-	/*
-	 * Take exclusive lock if
-	 * - Parallel direct writes are disabled - a user space decision
-	 * - Parallel direct writes are enabled and i_size is being extended.
-	 * - Shared mmap on direct_io file is supported (FUSE_DIRECT_IO_ALLOW_MMAP).
-	 *   This might not be needed at all, but needs further investigation.
-	 */
-	if (exclusive_lock)
-		inode_lock(inode);
-	else {
-		inode_lock_shared(inode);
-
-		/* A race with truncate might have come up as the decision for
-		 * the lock type was done without holding the lock, check again.
-		 */
-		if (fuse_direct_write_extending_i_size(iocb, from)) {
-			inode_unlock_shared(inode);
-			inode_lock(inode);
-			exclusive_lock = true;
-		}
-	}
+	bool exclusive;
 
+	fuse_dio_lock(iocb, from, &exclusive);
 	res = generic_write_checks(iocb, from);
 	if (res > 0) {
-		if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
+		task_io_account_write(res);
+		if (!is_sync_kiocb(iocb)) {
 			res = fuse_direct_IO(iocb, from);
 		} else {
+			struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
+
 			res = fuse_direct_io(&io, from, &iocb->ki_pos,
 					     FUSE_DIO_WRITE);
 			fuse_write_update_attr(inode, iocb->ki_pos, res);
 		}
 	}
-	if (exclusive_lock)
-		inode_unlock(inode);
-	else
-		inode_unlock_shared(inode);
+	fuse_dio_unlock(iocb, exclusive);
 
 	return res;
 }
@@ -1631,10 +1712,13 @@ static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	if (FUSE_IS_DAX(inode))
 		return fuse_dax_read_iter(iocb, to);
 
-	if (!(ff->open_flags & FOPEN_DIRECT_IO))
-		return fuse_cache_read_iter(iocb, to);
-	else
+	/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
+	if (ff->open_flags & FOPEN_DIRECT_IO)
 		return fuse_direct_read_iter(iocb, to);
+	else if (fuse_file_passthrough(ff))
+		return fuse_passthrough_read_iter(iocb, to);
+	else
+		return fuse_cache_read_iter(iocb, to);
 }
 
 static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
@@ -1649,32 +1733,54 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (FUSE_IS_DAX(inode))
 		return fuse_dax_write_iter(iocb, from);
 
-	if (!(ff->open_flags & FOPEN_DIRECT_IO))
+	/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
+	if (ff->open_flags & FOPEN_DIRECT_IO)
+		return fuse_direct_write_iter(iocb, from);
+	else if (fuse_file_passthrough(ff))
+		return fuse_passthrough_write_iter(iocb, from);
+	else
 		return fuse_cache_write_iter(iocb, from);
+}
+
+static ssize_t fuse_splice_read(struct file *in, loff_t *ppos,
+				struct pipe_inode_info *pipe, size_t len,
+				unsigned int flags)
+{
+	struct fuse_file *ff = in->private_data;
+
+	/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
+	if (fuse_file_passthrough(ff) && !(ff->open_flags & FOPEN_DIRECT_IO))
+		return fuse_passthrough_splice_read(in, ppos, pipe, len, flags);
 	else
-		return fuse_direct_write_iter(iocb, from);
+		return filemap_splice_read(in, ppos, pipe, len, flags);
+}
+
+static ssize_t fuse_splice_write(struct pipe_inode_info *pipe, struct file *out,
+				 loff_t *ppos, size_t len, unsigned int flags)
+{
+	struct fuse_file *ff = out->private_data;
+
+	/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
+	if (fuse_file_passthrough(ff) && !(ff->open_flags & FOPEN_DIRECT_IO))
+		return fuse_passthrough_splice_write(pipe, out, ppos, len, flags);
+	else
+		return iter_file_splice_write(pipe, out, ppos, len, flags);
 }
 
 static void fuse_writepage_free(struct fuse_writepage_args *wpa)
 {
 	struct fuse_args_pages *ap = &wpa->ia.ap;
-	int i;
 
 	if (wpa->bucket)
 		fuse_sync_bucket_dec(wpa->bucket);
 
-	for (i = 0; i < ap->num_pages; i++)
-		__free_page(ap->pages[i]);
-
-	if (wpa->ia.ff)
-		fuse_file_put(wpa->ia.ff, false, false);
+	fuse_file_put(wpa->ia.ff, false);
 
-	kfree(ap->pages);
+	kfree(ap->folios);
 	kfree(wpa);
 }
 
-static void fuse_writepage_finish(struct fuse_mount *fm,
-				  struct fuse_writepage_args *wpa)
+static void fuse_writepage_finish(struct fuse_writepage_args *wpa)
 {
 	struct fuse_args_pages *ap = &wpa->ia.ap;
 	struct inode *inode = wpa->inode;
@@ -1682,11 +1788,17 @@ static void fuse_writepage_finish(struct fuse_mount *fm,
 	struct backing_dev_info *bdi = inode_to_bdi(inode);
 	int i;
 
-	for (i = 0; i < ap->num_pages; i++) {
+	for (i = 0; i < ap->num_folios; i++) {
+		/*
+		 * Benchmarks showed that ending writeback within the
+		 * scope of the fi->lock alleviates xarray lock
+		 * contention and noticeably improves performance.
+		 */
+		folio_end_writeback(ap->folios[i]);
 		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
-		dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP);
 		wb_writeout_inc(&bdi->wb);
 	}
+
 	wake_up(&fi->page_waitq);
 }
 
@@ -1696,12 +1808,15 @@ static void fuse_send_writepage(struct fuse_mount *fm,
 __releases(fi->lock)
 __acquires(fi->lock)
 {
-	struct fuse_writepage_args *aux, *next;
 	struct fuse_inode *fi = get_fuse_inode(wpa->inode);
+	struct fuse_args_pages *ap = &wpa->ia.ap;
 	struct fuse_write_in *inarg = &wpa->ia.write.in;
-	struct fuse_args *args = &wpa->ia.ap.args;
-	__u64 data_size = wpa->ia.ap.num_pages * PAGE_SIZE;
-	int err;
+	struct fuse_args *args = &ap->args;
+	__u64 data_size = 0;
+	int err, i;
+
+	for (i = 0; i < ap->num_folios; i++)
+		data_size += ap->descs[i].length;
 
 	fi->writectr++;
 	if (inarg->offset + data_size <= size) {
@@ -1732,17 +1847,8 @@ __acquires(fi->lock)
 
  out_free:
 	fi->writectr--;
-	rb_erase(&wpa->writepages_entry, &fi->writepages);
-	fuse_writepage_finish(fm, wpa);
+	fuse_writepage_finish(wpa);
 	spin_unlock(&fi->lock);
-
-	/* After fuse_writepage_finish() aux request list is private */
-	for (aux = wpa->next; aux; aux = next) {
-		next = aux->next;
-		aux->next = NULL;
-		fuse_writepage_free(aux);
-	}
-
 	fuse_writepage_free(wpa);
 	spin_lock(&fi->lock);
 }
@@ -1770,43 +1876,6 @@ __acquires(fi->lock)
 	}
 }
 
-static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root,
-						struct fuse_writepage_args *wpa)
-{
-	pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT;
-	pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1;
-	struct rb_node **p = &root->rb_node;
-	struct rb_node  *parent = NULL;
-
-	WARN_ON(!wpa->ia.ap.num_pages);
-	while (*p) {
-		struct fuse_writepage_args *curr;
-		pgoff_t curr_index;
-
-		parent = *p;
-		curr = rb_entry(parent, struct fuse_writepage_args,
-				writepages_entry);
-		WARN_ON(curr->inode != wpa->inode);
-		curr_index = curr->ia.write.in.offset >> PAGE_SHIFT;
-
-		if (idx_from >= curr_index + curr->ia.ap.num_pages)
-			p = &(*p)->rb_right;
-		else if (idx_to < curr_index)
-			p = &(*p)->rb_left;
-		else
-			return curr;
-	}
-
-	rb_link_node(&wpa->writepages_entry, parent, p);
-	rb_insert_color(&wpa->writepages_entry, root);
-	return NULL;
-}
-
-static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa)
-{
-	WARN_ON(fuse_insert_writeback(root, wpa));
-}
-
 static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
 			       int error)
 {
@@ -1826,44 +1895,8 @@ static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
 	if (!fc->writeback_cache)
 		fuse_invalidate_attr_mask(inode, FUSE_STATX_MODIFY);
 	spin_lock(&fi->lock);
-	rb_erase(&wpa->writepages_entry, &fi->writepages);
-	while (wpa->next) {
-		struct fuse_mount *fm = get_fuse_mount(inode);
-		struct fuse_write_in *inarg = &wpa->ia.write.in;
-		struct fuse_writepage_args *next = wpa->next;
-
-		wpa->next = next->next;
-		next->next = NULL;
-		next->ia.ff = fuse_file_get(wpa->ia.ff);
-		tree_insert(&fi->writepages, next);
-
-		/*
-		 * Skip fuse_flush_writepages() to make it easy to crop requests
-		 * based on primary request size.
-		 *
-		 * 1st case (trivial): there are no concurrent activities using
-		 * fuse_set/release_nowrite.  Then we're on safe side because
-		 * fuse_flush_writepages() would call fuse_send_writepage()
-		 * anyway.
-		 *
-		 * 2nd case: someone called fuse_set_nowrite and it is waiting
-		 * now for completion of all in-flight requests.  This happens
-		 * rarely and no more than once per page, so this should be
-		 * okay.
-		 *
-		 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
-		 * of fuse_set_nowrite..fuse_release_nowrite section.  The fact
-		 * that fuse_set_nowrite returned implies that all in-flight
-		 * requests were completed along with all of their secondary
-		 * requests.  Further primary requests are blocked by negative
-		 * writectr.  Hence there cannot be any in-flight requests and
-		 * no invocations of fuse_writepage_end() while we're in
-		 * fuse_set_nowrite..fuse_release_nowrite section.
-		 */
-		fuse_send_writepage(fm, next, inarg->offset + inarg->size);
-	}
 	fi->writectr--;
-	fuse_writepage_finish(fm, wpa);
+	fuse_writepage_finish(wpa);
 	spin_unlock(&fi->lock);
 	fuse_writepage_free(wpa);
 }
@@ -1909,7 +1942,7 @@ int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
 	ff = __fuse_write_file_get(fi);
 	err = fuse_flush_times(inode, ff);
 	if (ff)
-		fuse_file_put(ff, false, false);
+		fuse_file_put(ff, false);
 
 	return err;
 }
@@ -1922,9 +1955,9 @@ static struct fuse_writepage_args *fuse_writepage_args_alloc(void)
 	wpa = kzalloc(sizeof(*wpa), GFP_NOFS);
 	if (wpa) {
 		ap = &wpa->ia.ap;
-		ap->num_pages = 0;
-		ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs);
-		if (!ap->pages) {
+		ap->num_folios = 0;
+		ap->folios = fuse_folios_alloc(1, GFP_NOFS, &ap->descs);
+		if (!ap->folios) {
 			kfree(wpa);
 			wpa = NULL;
 		}
@@ -1947,128 +1980,113 @@ static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
 	rcu_read_unlock();
 }
 
-static int fuse_writepage_locked(struct page *page)
+static void fuse_writepage_args_page_fill(struct fuse_writepage_args *wpa, struct folio *folio,
+					  uint32_t folio_index)
 {
-	struct address_space *mapping = page->mapping;
-	struct inode *inode = mapping->host;
+	struct inode *inode = folio->mapping->host;
+	struct fuse_args_pages *ap = &wpa->ia.ap;
+
+	ap->folios[folio_index] = folio;
+	ap->descs[folio_index].offset = 0;
+	ap->descs[folio_index].length = folio_size(folio);
+
+	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
+}
+
+static struct fuse_writepage_args *fuse_writepage_args_setup(struct folio *folio,
+							     struct fuse_file *ff)
+{
+	struct inode *inode = folio->mapping->host;
 	struct fuse_conn *fc = get_fuse_conn(inode);
-	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_writepage_args *wpa;
 	struct fuse_args_pages *ap;
-	struct page *tmp_page;
-	int error = -ENOMEM;
-
-	set_page_writeback(page);
 
 	wpa = fuse_writepage_args_alloc();
 	if (!wpa)
-		goto err;
-	ap = &wpa->ia.ap;
-
-	tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
-	if (!tmp_page)
-		goto err_free;
-
-	error = -EIO;
-	wpa->ia.ff = fuse_write_file_get(fi);
-	if (!wpa->ia.ff)
-		goto err_nofile;
+		return NULL;
 
 	fuse_writepage_add_to_bucket(fc, wpa);
-	fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);
-
-	copy_highpage(tmp_page, page);
+	fuse_write_args_fill(&wpa->ia, ff, folio_pos(folio), 0);
 	wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
-	wpa->next = NULL;
+	wpa->inode = inode;
+	wpa->ia.ff = ff;
+
+	ap = &wpa->ia.ap;
 	ap->args.in_pages = true;
-	ap->num_pages = 1;
-	ap->pages[0] = tmp_page;
-	ap->descs[0].offset = 0;
-	ap->descs[0].length = PAGE_SIZE;
 	ap->args.end = fuse_writepage_end;
-	wpa->inode = inode;
 
-	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
-	inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
+	return wpa;
+}
+
+static int fuse_writepage_locked(struct folio *folio)
+{
+	struct address_space *mapping = folio->mapping;
+	struct inode *inode = mapping->host;
+	struct fuse_inode *fi = get_fuse_inode(inode);
+	struct fuse_writepage_args *wpa;
+	struct fuse_args_pages *ap;
+	struct fuse_file *ff;
+	int error = -EIO;
+
+	ff = fuse_write_file_get(fi);
+	if (!ff)
+		goto err;
+
+	wpa = fuse_writepage_args_setup(folio, ff);
+	error = -ENOMEM;
+	if (!wpa)
+		goto err_writepage_args;
+
+	ap = &wpa->ia.ap;
+	ap->num_folios = 1;
+
+	folio_start_writeback(folio);
+	fuse_writepage_args_page_fill(wpa, folio, 0);
 
 	spin_lock(&fi->lock);
-	tree_insert(&fi->writepages, wpa);
 	list_add_tail(&wpa->queue_entry, &fi->queued_writes);
 	fuse_flush_writepages(inode);
 	spin_unlock(&fi->lock);
 
-	end_page_writeback(page);
-
 	return 0;
 
-err_nofile:
-	__free_page(tmp_page);
-err_free:
-	kfree(wpa);
+err_writepage_args:
+	fuse_file_put(ff, false);
 err:
-	mapping_set_error(page->mapping, error);
-	end_page_writeback(page);
+	mapping_set_error(folio->mapping, error);
 	return error;
 }
 
-static int fuse_writepage(struct page *page, struct writeback_control *wbc)
-{
-	struct fuse_conn *fc = get_fuse_conn(page->mapping->host);
-	int err;
-
-	if (fuse_page_is_writeback(page->mapping->host, page->index)) {
-		/*
-		 * ->writepages() should be called for sync() and friends.  We
-		 * should only get here on direct reclaim and then we are
-		 * allowed to skip a page which is already in flight
-		 */
-		WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
-
-		redirty_page_for_writepage(wbc, page);
-		unlock_page(page);
-		return 0;
-	}
-
-	if (wbc->sync_mode == WB_SYNC_NONE &&
-	    fc->num_background >= fc->congestion_threshold)
-		return AOP_WRITEPAGE_ACTIVATE;
-
-	err = fuse_writepage_locked(page);
-	unlock_page(page);
-
-	return err;
-}
-
 struct fuse_fill_wb_data {
 	struct fuse_writepage_args *wpa;
 	struct fuse_file *ff;
 	struct inode *inode;
-	struct page **orig_pages;
-	unsigned int max_pages;
+	unsigned int max_folios;
+	unsigned int nr_pages;
 };
 
 static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
 {
 	struct fuse_args_pages *ap = &data->wpa->ia.ap;
 	struct fuse_conn *fc = get_fuse_conn(data->inode);
-	struct page **pages;
-	struct fuse_page_desc *descs;
-	unsigned int npages = min_t(unsigned int,
-				    max_t(unsigned int, data->max_pages * 2,
-					  FUSE_DEFAULT_MAX_PAGES_PER_REQ),
+	struct folio **folios;
+	struct fuse_folio_desc *descs;
+	unsigned int nfolios = min_t(unsigned int,
+				     max_t(unsigned int, data->max_folios * 2,
+					   FUSE_DEFAULT_MAX_PAGES_PER_REQ),
 				    fc->max_pages);
-	WARN_ON(npages <= data->max_pages);
+	WARN_ON(nfolios <= data->max_folios);
 
-	pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
-	if (!pages)
+	folios = fuse_folios_alloc(nfolios, GFP_NOFS, &descs);
+	if (!folios)
 		return false;
 
-	memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
-	memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
-	kfree(ap->pages);
-	ap->pages = pages;
+	memcpy(folios, ap->folios, sizeof(struct folio *) * ap->num_folios);
+	memcpy(descs, ap->descs, sizeof(struct fuse_folio_desc) * ap->num_folios);
+	kfree(ap->folios);
+	ap->folios = folios;
 	ap->descs = descs;
-	data->max_pages = npages;
+	data->max_folios = nfolios;
 
 	return true;
 }
@@ -2078,104 +2096,33 @@ static void fuse_writepages_send(struct fuse_fill_wb_data *data)
 	struct fuse_writepage_args *wpa = data->wpa;
 	struct inode *inode = data->inode;
 	struct fuse_inode *fi = get_fuse_inode(inode);
-	int num_pages = wpa->ia.ap.num_pages;
-	int i;
 
-	wpa->ia.ff = fuse_file_get(data->ff);
 	spin_lock(&fi->lock);
 	list_add_tail(&wpa->queue_entry, &fi->queued_writes);
 	fuse_flush_writepages(inode);
 	spin_unlock(&fi->lock);
-
-	for (i = 0; i < num_pages; i++)
-		end_page_writeback(data->orig_pages[i]);
 }
 
-/*
- * Check under fi->lock if the page is under writeback, and insert it onto the
- * rb_tree if not. Otherwise iterate auxiliary write requests, to see if there's
- * one already added for a page at this offset.  If there's none, then insert
- * this new request onto the auxiliary list, otherwise reuse the existing one by
- * swapping the new temp page with the old one.
- */
-static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
-			       struct page *page)
-{
-	struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
-	struct fuse_writepage_args *tmp;
-	struct fuse_writepage_args *old_wpa;
-	struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
-
-	WARN_ON(new_ap->num_pages != 0);
-	new_ap->num_pages = 1;
-
-	spin_lock(&fi->lock);
-	old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa);
-	if (!old_wpa) {
-		spin_unlock(&fi->lock);
-		return true;
-	}
-
-	for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
-		pgoff_t curr_index;
-
-		WARN_ON(tmp->inode != new_wpa->inode);
-		curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
-		if (curr_index == page->index) {
-			WARN_ON(tmp->ia.ap.num_pages != 1);
-			swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
-			break;
-		}
-	}
-
-	if (!tmp) {
-		new_wpa->next = old_wpa->next;
-		old_wpa->next = new_wpa;
-	}
-
-	spin_unlock(&fi->lock);
-
-	if (tmp) {
-		struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
-
-		dec_wb_stat(&bdi->wb, WB_WRITEBACK);
-		dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
-		wb_writeout_inc(&bdi->wb);
-		fuse_writepage_free(new_wpa);
-	}
-
-	return false;
-}
-
-static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
+static bool fuse_writepage_need_send(struct fuse_conn *fc, struct folio *folio,
 				     struct fuse_args_pages *ap,
 				     struct fuse_fill_wb_data *data)
 {
-	WARN_ON(!ap->num_pages);
-
-	/*
-	 * Being under writeback is unlikely but possible.  For example direct
-	 * read to an mmaped fuse file will set the page dirty twice; once when
-	 * the pages are faulted with get_user_pages(), and then after the read
-	 * completed.
-	 */
-	if (fuse_page_is_writeback(data->inode, page->index))
-		return true;
+	WARN_ON(!ap->num_folios);
 
 	/* Reached max pages */
-	if (ap->num_pages == fc->max_pages)
+	if (data->nr_pages + folio_nr_pages(folio) > fc->max_pages)
 		return true;
 
 	/* Reached max write bytes */
-	if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)
+	if ((data->nr_pages * PAGE_SIZE) + folio_size(folio) > fc->max_write)
 		return true;
 
 	/* Discontinuity */
-	if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
+	if (folio_next_index(ap->folios[ap->num_folios - 1]) != folio->index)
 		return true;
 
 	/* Need to grow the pages array?  If so, did the expansion fail? */
-	if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))
+	if (ap->num_folios == data->max_folios && !fuse_pages_realloc(data))
 		return true;
 
 	return false;
@@ -2190,7 +2137,6 @@ static int fuse_writepages_fill(struct folio *folio,
 	struct inode *inode = data->inode;
 	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_conn *fc = get_fuse_conn(inode);
-	struct page *tmp_page;
 	int err;
 
 	if (!data->ff) {
@@ -2200,74 +2146,30 @@ static int fuse_writepages_fill(struct folio *folio,
 			goto out_unlock;
 	}
 
-	if (wpa && fuse_writepage_need_send(fc, &folio->page, ap, data)) {
+	if (wpa && fuse_writepage_need_send(fc, folio, ap, data)) {
 		fuse_writepages_send(data);
 		data->wpa = NULL;
+		data->nr_pages = 0;
 	}
 
-	err = -ENOMEM;
-	tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
-	if (!tmp_page)
-		goto out_unlock;
-
-	/*
-	 * The page must not be redirtied until the writeout is completed
-	 * (i.e. userspace has sent a reply to the write request).  Otherwise
-	 * there could be more than one temporary page instance for each real
-	 * page.
-	 *
-	 * This is ensured by holding the page lock in page_mkwrite() while
-	 * checking fuse_page_is_writeback().  We already hold the page lock
-	 * since clear_page_dirty_for_io() and keep it held until we add the
-	 * request to the fi->writepages list and increment ap->num_pages.
-	 * After this fuse_page_is_writeback() will indicate that the page is
-	 * under writeback, so we can release the page lock.
-	 */
 	if (data->wpa == NULL) {
 		err = -ENOMEM;
-		wpa = fuse_writepage_args_alloc();
-		if (!wpa) {
-			__free_page(tmp_page);
+		wpa = fuse_writepage_args_setup(folio, data->ff);
+		if (!wpa)
 			goto out_unlock;
-		}
-		fuse_writepage_add_to_bucket(fc, wpa);
-
-		data->max_pages = 1;
-
+		fuse_file_get(wpa->ia.ff);
+		data->max_folios = 1;
 		ap = &wpa->ia.ap;
-		fuse_write_args_fill(&wpa->ia, data->ff, folio_pos(folio), 0);
-		wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
-		wpa->next = NULL;
-		ap->args.in_pages = true;
-		ap->args.end = fuse_writepage_end;
-		ap->num_pages = 0;
-		wpa->inode = inode;
 	}
 	folio_start_writeback(folio);
 
-	copy_highpage(tmp_page, &folio->page);
-	ap->pages[ap->num_pages] = tmp_page;
-	ap->descs[ap->num_pages].offset = 0;
-	ap->descs[ap->num_pages].length = PAGE_SIZE;
-	data->orig_pages[ap->num_pages] = &folio->page;
-
-	inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
-	inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
+	fuse_writepage_args_page_fill(wpa, folio, ap->num_folios);
+	data->nr_pages += folio_nr_pages(folio);
 
 	err = 0;
-	if (data->wpa) {
-		/*
-		 * Protected by fi->lock against concurrent access by
-		 * fuse_page_is_writeback().
-		 */
-		spin_lock(&fi->lock);
-		ap->num_pages++;
-		spin_unlock(&fi->lock);
-	} else if (fuse_writepage_add(wpa, &folio->page)) {
+	ap->num_folios++;
+	if (!data->wpa)
 		data->wpa = wpa;
-	} else {
-		folio_end_writeback(folio);
-	}
 out_unlock:
 	folio_unlock(folio);
 
@@ -2293,23 +2195,16 @@ static int fuse_writepages(struct address_space *mapping,
 	data.inode = inode;
 	data.wpa = NULL;
 	data.ff = NULL;
-
-	err = -ENOMEM;
-	data.orig_pages = kcalloc(fc->max_pages,
-				  sizeof(struct page *),
-				  GFP_NOFS);
-	if (!data.orig_pages)
-		goto out;
+	data.nr_pages = 0;
 
 	err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
 	if (data.wpa) {
-		WARN_ON(!data.wpa->ia.ap.num_pages);
+		WARN_ON(!data.wpa->ia.ap.num_folios);
 		fuse_writepages_send(&data);
 	}
 	if (data.ff)
-		fuse_file_put(data.ff, false, false);
+		fuse_file_put(data.ff, false);
 
-	kfree(data.orig_pages);
 out:
 	return err;
 }
@@ -2319,76 +2214,75 @@ out:
  * but how to implement it without killing performance need more thinking.
  */
 static int fuse_write_begin(struct file *file, struct address_space *mapping,
-		loff_t pos, unsigned len, struct page **pagep, void **fsdata)
+		loff_t pos, unsigned len, struct folio **foliop, void **fsdata)
 {
 	pgoff_t index = pos >> PAGE_SHIFT;
 	struct fuse_conn *fc = get_fuse_conn(file_inode(file));
-	struct page *page;
+	struct folio *folio;
 	loff_t fsize;
 	int err = -ENOMEM;
 
 	WARN_ON(!fc->writeback_cache);
 
-	page = grab_cache_page_write_begin(mapping, index);
-	if (!page)
+	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
+			mapping_gfp_mask(mapping));
+	if (IS_ERR(folio))
 		goto error;
 
-	fuse_wait_on_page_writeback(mapping->host, page->index);
-
-	if (PageUptodate(page) || len == PAGE_SIZE)
+	if (folio_test_uptodate(folio) || len >= folio_size(folio))
 		goto success;
 	/*
-	 * Check if the start this page comes after the end of file, in which
-	 * case the readpage can be optimized away.
+	 * Check if the start of this folio comes after the end of file,
+	 * in which case the readpage can be optimized away.
 	 */
 	fsize = i_size_read(mapping->host);
-	if (fsize <= (pos & PAGE_MASK)) {
-		size_t off = pos & ~PAGE_MASK;
+	if (fsize <= folio_pos(folio)) {
+		size_t off = offset_in_folio(folio, pos);
 		if (off)
-			zero_user_segment(page, 0, off);
+			folio_zero_segment(folio, 0, off);
 		goto success;
 	}
-	err = fuse_do_readpage(file, page);
+	err = fuse_do_readfolio(file, folio);
 	if (err)
 		goto cleanup;
 success:
-	*pagep = page;
+	*foliop = folio;
 	return 0;
 
 cleanup:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 error:
 	return err;
 }
 
 static int fuse_write_end(struct file *file, struct address_space *mapping,
 		loff_t pos, unsigned len, unsigned copied,
-		struct page *page, void *fsdata)
+		struct folio *folio, void *fsdata)
 {
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio->mapping->host;
 
 	/* Haven't copied anything?  Skip zeroing, size extending, dirtying. */
 	if (!copied)
 		goto unlock;
 
 	pos += copied;
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		/* Zero any unwritten bytes at the end of the page */
 		size_t endoff = pos & ~PAGE_MASK;
 		if (endoff)
-			zero_user_segment(page, endoff, PAGE_SIZE);
-		SetPageUptodate(page);
+			folio_zero_segment(folio, endoff, PAGE_SIZE);
+		folio_mark_uptodate(folio);
 	}
 
 	if (pos > inode->i_size)
 		i_size_write(inode, pos);
 
-	set_page_dirty(page);
+	folio_mark_dirty(folio);
 
 unlock:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 
 	return copied;
 }
@@ -2397,13 +2291,9 @@ static int fuse_launder_folio(struct folio *folio)
 {
 	int err = 0;
 	if (folio_clear_dirty_for_io(folio)) {
-		struct inode *inode = folio->mapping->host;
-
-		/* Serialize with pending writeback for the same page */
-		fuse_wait_on_page_writeback(inode, folio->index);
-		err = fuse_writepage_locked(&folio->page);
+		err = fuse_writepage_locked(folio);
 		if (!err)
-			fuse_wait_on_page_writeback(inode, folio->index);
+			folio_wait_writeback(folio);
 	}
 	return err;
 }
@@ -2437,17 +2327,17 @@ static void fuse_vma_close(struct vm_area_struct *vma)
  */
 static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
 {
-	struct page *page = vmf->page;
+	struct folio *folio = page_folio(vmf->page);
 	struct inode *inode = file_inode(vmf->vma->vm_file);
 
 	file_update_time(vmf->vma->vm_file);
-	lock_page(page);
-	if (page->mapping != inode->i_mapping) {
-		unlock_page(page);
+	folio_lock(folio);
+	if (folio->mapping != inode->i_mapping) {
+		folio_unlock(folio);
 		return VM_FAULT_NOPAGE;
 	}
 
-	fuse_wait_on_page_writeback(inode, page->index);
+	folio_wait_writeback(folio);
 	return VM_FAULT_LOCKED;
 }
 
@@ -2462,13 +2352,30 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = ff->fm->fc;
+	struct inode *inode = file_inode(file);
+	int rc;
 
 	/* DAX mmap is superior to direct_io mmap */
-	if (FUSE_IS_DAX(file_inode(file)))
+	if (FUSE_IS_DAX(inode))
 		return fuse_dax_mmap(file, vma);
 
+	/*
+	 * If inode is in passthrough io mode, because it has some file open
+	 * in passthrough mode, either mmap to backing file or fail mmap,
+	 * because mixing cached mmap and passthrough io mode is not allowed.
+	 */
+	if (fuse_file_passthrough(ff))
+		return fuse_passthrough_mmap(file, vma);
+	else if (fuse_inode_backing(get_fuse_inode(inode)))
+		return -ENODEV;
+
+	/*
+	 * FOPEN_DIRECT_IO handling is special compared to O_DIRECT,
+	 * as does not allow MAP_SHARED mmap without FUSE_DIRECT_IO_ALLOW_MMAP.
+	 */
 	if (ff->open_flags & FOPEN_DIRECT_IO) {
-		/* Can't provide the coherency needed for MAP_SHARED
+		/*
+		 * Can't provide the coherency needed for MAP_SHARED
 		 * if FUSE_DIRECT_IO_ALLOW_MMAP isn't set.
 		 */
 		if ((vma->vm_flags & VM_MAYSHARE) && !fc->direct_io_allow_mmap)
@@ -2476,7 +2383,21 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
 
 		invalidate_inode_pages2(file->f_mapping);
 
-		return generic_file_mmap(file, vma);
+		if (!(vma->vm_flags & VM_MAYSHARE)) {
+			/* MAP_PRIVATE */
+			return generic_file_mmap(file, vma);
+		}
+
+		/*
+		 * First mmap of direct_io file enters caching inode io mode.
+		 * Also waits for parallel dio writers to go into serial mode
+		 * (exclusive instead of shared lock).
+		 * After first mmap, the inode stays in caching io mode until
+		 * the direct_io file release.
+		 */
+		rc = fuse_file_cached_io_open(inode, ff);
+		if (rc)
+			return rc;
 	}
 
 	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
@@ -2509,14 +2430,14 @@ static int convert_fuse_file_lock(struct fuse_conn *fc,
 		 * translate it into the caller's pid namespace.
 		 */
 		rcu_read_lock();
-		fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
+		fl->c.flc_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
 		rcu_read_unlock();
 		break;
 
 	default:
 		return -EIO;
 	}
-	fl->fl_type = ffl->type;
+	fl->c.flc_type = ffl->type;
 	return 0;
 }
 
@@ -2530,10 +2451,10 @@ static void fuse_lk_fill(struct fuse_args *args, struct file *file,
 
 	memset(inarg, 0, sizeof(*inarg));
 	inarg->fh = ff->fh;
-	inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
+	inarg->owner = fuse_lock_owner_id(fc, fl->c.flc_owner);
 	inarg->lk.start = fl->fl_start;
 	inarg->lk.end = fl->fl_end;
-	inarg->lk.type = fl->fl_type;
+	inarg->lk.type = fl->c.flc_type;
 	inarg->lk.pid = pid;
 	if (flock)
 		inarg->lk_flags |= FUSE_LK_FLOCK;
@@ -2570,8 +2491,8 @@ static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
 	struct fuse_mount *fm = get_fuse_mount(inode);
 	FUSE_ARGS(args);
 	struct fuse_lk_in inarg;
-	int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
-	struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL;
+	int opcode = (fl->c.flc_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
+	struct pid *pid = fl->c.flc_type != F_UNLCK ? task_tgid(current) : NULL;
 	pid_t pid_nr = pid_nr_ns(pid, fm->fc->pid_ns);
 	int err;
 
@@ -2580,10 +2501,6 @@ static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
 		return -ENOLCK;
 	}
 
-	/* Unlock on close is handled by the flush method */
-	if ((fl->fl_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX)
-		return 0;
-
 	fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
 	err = fuse_simple_request(fm, &args);
 
@@ -2871,7 +2788,7 @@ static void fuse_do_truncate(struct file *file)
 	attr.ia_file = file;
 	attr.ia_valid |= ATTR_FILE;
 
-	fuse_do_setattr(file_dentry(file), &attr, file);
+	fuse_do_setattr(file_mnt_idmap(file), file_dentry(file), &attr, file);
 }
 
 static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
@@ -3014,7 +2931,7 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 	inode_lock(inode);
 	if (block_faults) {
 		filemap_invalidate_lock(inode->i_mapping);
-		err = fuse_dax_break_layouts(inode, 0, 0);
+		err = fuse_dax_break_layouts(inode, 0, -1);
 		if (err)
 			goto out;
 	}
@@ -3213,8 +3130,8 @@ static const struct file_operations fuse_file_operations = {
 	.lock		= fuse_file_lock,
 	.get_unmapped_area = thp_get_unmapped_area,
 	.flock		= fuse_file_flock,
-	.splice_read	= filemap_splice_read,
-	.splice_write	= iter_file_splice_write,
+	.splice_read	= fuse_splice_read,
+	.splice_write	= fuse_splice_write,
 	.unlocked_ioctl	= fuse_file_ioctl,
 	.compat_ioctl	= fuse_file_compat_ioctl,
 	.poll		= fuse_file_poll,
@@ -3225,10 +3142,10 @@ static const struct file_operations fuse_file_operations = {
 static const struct address_space_operations fuse_file_aops  = {
 	.read_folio	= fuse_read_folio,
 	.readahead	= fuse_readahead,
-	.writepage	= fuse_writepage,
 	.writepages	= fuse_writepages,
 	.launder_folio	= fuse_launder_folio,
 	.dirty_folio	= filemap_dirty_folio,
+	.migrate_folio	= filemap_migrate_folio,
 	.bmap		= fuse_bmap,
 	.direct_IO	= fuse_direct_IO,
 	.write_begin	= fuse_write_begin,
@@ -3238,15 +3155,19 @@ static const struct address_space_operations fuse_file_aops  = {
 void fuse_init_file_inode(struct inode *inode, unsigned int flags)
 {
 	struct fuse_inode *fi = get_fuse_inode(inode);
+	struct fuse_conn *fc = get_fuse_conn(inode);
 
 	inode->i_fop = &fuse_file_operations;
 	inode->i_data.a_ops = &fuse_file_aops;
+	if (fc->writeback_cache)
+		mapping_set_writeback_may_deadlock_on_reclaim(&inode->i_data);
 
 	INIT_LIST_HEAD(&fi->write_files);
 	INIT_LIST_HEAD(&fi->queued_writes);
 	fi->writectr = 0;
+	fi->iocachectr = 0;
 	init_waitqueue_head(&fi->page_waitq);
-	fi->writepages = RB_ROOT;
+	init_waitqueue_head(&fi->direct_io_waitq);
 
 	if (IS_ENABLED(CONFIG_FUSE_DAX))
 		fuse_dax_inode_init(inode, flags);