1 files changed, 393 insertions, 195 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 1a8f82f478cb..51e31df4c546 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -6,7 +6,9 @@
   See the file COPYING.
 */
 
+#include "dev_uring_i.h"
 #include "fuse_i.h"
+#include "fuse_dev_i.h"
 
 #include <linux/init.h>
 #include <linux/module.h>
@@ -22,24 +24,14 @@
 #include <linux/splice.h>
 #include <linux/sched.h>
 
+#define CREATE_TRACE_POINTS
+#include "fuse_trace.h"
+
 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
 MODULE_ALIAS("devname:fuse");
 
-/* Ordinary requests have even IDs, while interrupts IDs are odd */
-#define FUSE_INT_REQ_BIT (1ULL << 0)
-#define FUSE_REQ_ID_STEP (1ULL << 1)
-
 static struct kmem_cache *fuse_req_cachep;
 
-static struct fuse_dev *fuse_get_dev(struct file *file)
-{
-	/*
-	 * Lockless access is OK, because file->private data is set
-	 * once during mount and is valid until the file is released.
-	 */
-	return READ_ONCE(file->private_data);
-}
-
 static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req)
 {
 	INIT_LIST_HEAD(&req->list);
@@ -84,7 +76,8 @@ void fuse_set_initialized(struct fuse_conn *fc)
 
 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
 {
-	return !fc->initialized || (for_background && fc->blocked);
+	return !fc->initialized || (for_background && fc->blocked) ||
+	       (fc->io_uring && fc->connected && !fuse_uring_ready(fc));
 }
 
 static void fuse_drop_waiting(struct fuse_conn *fc)
@@ -103,11 +96,17 @@ static void fuse_drop_waiting(struct fuse_conn *fc)
 
 static void fuse_put_request(struct fuse_req *req);
 
-static struct fuse_req *fuse_get_req(struct fuse_mount *fm, bool for_background)
+static struct fuse_req *fuse_get_req(struct mnt_idmap *idmap,
+				     struct fuse_mount *fm,
+				     bool for_background)
 {
 	struct fuse_conn *fc = fm->fc;
 	struct fuse_req *req;
+	bool no_idmap = !fm->sb || (fm->sb->s_iflags & SB_I_NOIDMAP);
+	kuid_t fsuid;
+	kgid_t fsgid;
 	int err;
+
 	atomic_inc(&fc->num_waiting);
 
 	if (fuse_block_alloc(fc, for_background)) {
@@ -135,19 +134,32 @@ static struct fuse_req *fuse_get_req(struct fuse_mount *fm, bool for_background)
 		goto out;
 	}
 
-	req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
-	req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
 	req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 
 	__set_bit(FR_WAITING, &req->flags);
 	if (for_background)
 		__set_bit(FR_BACKGROUND, &req->flags);
 
-	if (unlikely(req->in.h.uid == ((uid_t)-1) ||
-		     req->in.h.gid == ((gid_t)-1))) {
+	/*
+	 * Keep the old behavior when idmappings support was not
+	 * declared by a FUSE server.
+	 *
+	 * For those FUSE servers who support idmapped mounts,
+	 * we send UID/GID only along with "inode creation"
+	 * fuse requests, otherwise idmap == &invalid_mnt_idmap and
+	 * req->in.h.{u,g}id will be equal to FUSE_INVALID_UIDGID.
+	 */
+	fsuid = no_idmap ? current_fsuid() : mapped_fsuid(idmap, fc->user_ns);
+	fsgid = no_idmap ? current_fsgid() : mapped_fsgid(idmap, fc->user_ns);
+	req->in.h.uid = from_kuid(fc->user_ns, fsuid);
+	req->in.h.gid = from_kgid(fc->user_ns, fsgid);
+
+	if (no_idmap && unlikely(req->in.h.uid == ((uid_t)-1) ||
+				 req->in.h.gid == ((gid_t)-1))) {
 		fuse_put_request(req);
 		return ERR_PTR(-EOVERFLOW);
 	}
+
 	return req;
 
  out:
@@ -192,14 +204,25 @@ unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args)
 }
 EXPORT_SYMBOL_GPL(fuse_len_args);
 
-u64 fuse_get_unique(struct fuse_iqueue *fiq)
+static u64 fuse_get_unique_locked(struct fuse_iqueue *fiq)
 {
 	fiq->reqctr += FUSE_REQ_ID_STEP;
 	return fiq->reqctr;
 }
+
+u64 fuse_get_unique(struct fuse_iqueue *fiq)
+{
+	u64 ret;
+
+	spin_lock(&fiq->lock);
+	ret = fuse_get_unique_locked(fiq);
+	spin_unlock(&fiq->lock);
+
+	return ret;
+}
 EXPORT_SYMBOL_GPL(fuse_get_unique);
 
-static unsigned int fuse_req_hash(u64 unique)
+unsigned int fuse_req_hash(u64 unique)
 {
 	return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS);
 }
@@ -215,22 +238,71 @@ __releases(fiq->lock)
 	spin_unlock(&fiq->lock);
 }
 
+void fuse_dev_queue_forget(struct fuse_iqueue *fiq,
+			   struct fuse_forget_link *forget)
+{
+	spin_lock(&fiq->lock);
+	if (fiq->connected) {
+		fiq->forget_list_tail->next = forget;
+		fiq->forget_list_tail = forget;
+		fuse_dev_wake_and_unlock(fiq);
+	} else {
+		kfree(forget);
+		spin_unlock(&fiq->lock);
+	}
+}
+
+void fuse_dev_queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
+{
+	spin_lock(&fiq->lock);
+	if (list_empty(&req->intr_entry)) {
+		list_add_tail(&req->intr_entry, &fiq->interrupts);
+		/*
+		 * Pairs with smp_mb() implied by test_and_set_bit()
+		 * from fuse_request_end().
+		 */
+		smp_mb();
+		if (test_bit(FR_FINISHED, &req->flags)) {
+			list_del_init(&req->intr_entry);
+			spin_unlock(&fiq->lock);
+		} else  {
+			fuse_dev_wake_and_unlock(fiq);
+		}
+	} else {
+		spin_unlock(&fiq->lock);
+	}
+}
+
+static void fuse_dev_queue_req(struct fuse_iqueue *fiq, struct fuse_req *req)
+{
+	spin_lock(&fiq->lock);
+	if (fiq->connected) {
+		if (req->in.h.opcode != FUSE_NOTIFY_REPLY)
+			req->in.h.unique = fuse_get_unique_locked(fiq);
+		list_add_tail(&req->list, &fiq->pending);
+		fuse_dev_wake_and_unlock(fiq);
+	} else {
+		spin_unlock(&fiq->lock);
+		req->out.h.error = -ENOTCONN;
+		clear_bit(FR_PENDING, &req->flags);
+		fuse_request_end(req);
+	}
+}
+
 const struct fuse_iqueue_ops fuse_dev_fiq_ops = {
-	.wake_forget_and_unlock		= fuse_dev_wake_and_unlock,
-	.wake_interrupt_and_unlock	= fuse_dev_wake_and_unlock,
-	.wake_pending_and_unlock	= fuse_dev_wake_and_unlock,
+	.send_forget	= fuse_dev_queue_forget,
+	.send_interrupt	= fuse_dev_queue_interrupt,
+	.send_req	= fuse_dev_queue_req,
 };
 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
 
-static void queue_request_and_unlock(struct fuse_iqueue *fiq,
-				     struct fuse_req *req)
-__releases(fiq->lock)
+static void fuse_send_one(struct fuse_iqueue *fiq, struct fuse_req *req)
 {
 	req->in.h.len = sizeof(struct fuse_in_header) +
 		fuse_len_args(req->args->in_numargs,
 			      (struct fuse_arg *) req->args->in_args);
-	list_add_tail(&req->list, &fiq->pending);
-	fiq->ops->wake_pending_and_unlock(fiq);
+	trace_fuse_request_send(req);
+	fiq->ops->send_req(fiq, req);
 }
 
 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
@@ -241,15 +313,7 @@ void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 	forget->forget_one.nodeid = nodeid;
 	forget->forget_one.nlookup = nlookup;
 
-	spin_lock(&fiq->lock);
-	if (fiq->connected) {
-		fiq->forget_list_tail->next = forget;
-		fiq->forget_list_tail = forget;
-		fiq->ops->wake_forget_and_unlock(fiq);
-	} else {
-		kfree(forget);
-		spin_unlock(&fiq->lock);
-	}
+	fiq->ops->send_forget(fiq, forget);
 }
 
 static void flush_bg_queue(struct fuse_conn *fc)
@@ -263,9 +327,7 @@ static void flush_bg_queue(struct fuse_conn *fc)
 		req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
 		list_del(&req->list);
 		fc->active_background++;
-		spin_lock(&fiq->lock);
-		req->in.h.unique = fuse_get_unique(fiq);
-		queue_request_and_unlock(fiq, req);
+		fuse_send_one(fiq, req);
 	}
 }
 
@@ -286,6 +348,7 @@ void fuse_request_end(struct fuse_req *req)
 	if (test_and_set_bit(FR_FINISHED, &req->flags))
 		goto put_request;
 
+	trace_fuse_request_end(req);
 	/*
 	 * test_and_set_bit() implies smp_mb() between bit
 	 * changing and below FR_INTERRUPTED check. Pairs with
@@ -335,29 +398,12 @@ static int queue_interrupt(struct fuse_req *req)
 {
 	struct fuse_iqueue *fiq = &req->fm->fc->iq;
 
-	spin_lock(&fiq->lock);
 	/* Check for we've sent request to interrupt this req */
-	if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) {
-		spin_unlock(&fiq->lock);
+	if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags)))
 		return -EINVAL;
-	}
 
-	if (list_empty(&req->intr_entry)) {
-		list_add_tail(&req->intr_entry, &fiq->interrupts);
-		/*
-		 * Pairs with smp_mb() implied by test_and_set_bit()
-		 * from fuse_request_end().
-		 */
-		smp_mb();
-		if (test_bit(FR_FINISHED, &req->flags)) {
-			list_del_init(&req->intr_entry);
-			spin_unlock(&fiq->lock);
-			return 0;
-		}
-		fiq->ops->wake_interrupt_and_unlock(fiq);
-	} else {
-		spin_unlock(&fiq->lock);
-	}
+	fiq->ops->send_interrupt(fiq, req);
+
 	return 0;
 }
 
@@ -412,21 +458,15 @@ static void __fuse_request_send(struct fuse_req *req)
 	struct fuse_iqueue *fiq = &req->fm->fc->iq;
 
 	BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
-	spin_lock(&fiq->lock);
-	if (!fiq->connected) {
-		spin_unlock(&fiq->lock);
-		req->out.h.error = -ENOTCONN;
-	} else {
-		req->in.h.unique = fuse_get_unique(fiq);
-		/* acquire extra reference, since request is still needed
-		   after fuse_request_end() */
-		__fuse_get_request(req);
-		queue_request_and_unlock(fiq, req);
 
-		request_wait_answer(req);
-		/* Pairs with smp_wmb() in fuse_request_end() */
-		smp_rmb();
-	}
+	/* acquire extra reference, since request is still needed after
+	   fuse_request_end() */
+	__fuse_get_request(req);
+	fuse_send_one(fiq, req);
+
+	request_wait_answer(req);
+	/* Pairs with smp_wmb() in fuse_request_end() */
+	smp_rmb();
 }
 
 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
@@ -466,8 +506,14 @@ static void fuse_force_creds(struct fuse_req *req)
 {
 	struct fuse_conn *fc = req->fm->fc;
 
-	req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
-	req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
+	if (!req->fm->sb || req->fm->sb->s_iflags & SB_I_NOIDMAP) {
+		req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
+		req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
+	} else {
+		req->in.h.uid = FUSE_INVALID_UIDGID;
+		req->in.h.gid = FUSE_INVALID_UIDGID;
+	}
+
 	req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 }
 
@@ -482,7 +528,9 @@ static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
 		__set_bit(FR_ASYNC, &req->flags);
 }
 
-ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args)
+ssize_t __fuse_simple_request(struct mnt_idmap *idmap,
+			      struct fuse_mount *fm,
+			      struct fuse_args *args)
 {
 	struct fuse_conn *fc = fm->fc;
 	struct fuse_req *req;
@@ -499,7 +547,7 @@ ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args)
 		__set_bit(FR_FORCE, &req->flags);
 	} else {
 		WARN_ON(args->nocreds);
-		req = fuse_get_req(fm, false);
+		req = fuse_get_req(idmap, fm, false);
 		if (IS_ERR(req))
 			return PTR_ERR(req);
 	}
@@ -521,7 +569,25 @@ ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args)
 	return ret;
 }
 
-static bool fuse_request_queue_background(struct fuse_req *req)
+#ifdef CONFIG_FUSE_IO_URING
+static bool fuse_request_queue_background_uring(struct fuse_conn *fc,
+					       struct fuse_req *req)
+{
+	struct fuse_iqueue *fiq = &fc->iq;
+
+	req->in.h.unique = fuse_get_unique(fiq);
+	req->in.h.len = sizeof(struct fuse_in_header) +
+		fuse_len_args(req->args->in_numargs,
+			      (struct fuse_arg *) req->args->in_args);
+
+	return fuse_uring_queue_bq_req(req);
+}
+#endif
+
+/*
+ * @return true if queued
+ */
+static int fuse_request_queue_background(struct fuse_req *req)
 {
 	struct fuse_mount *fm = req->fm;
 	struct fuse_conn *fc = fm->fc;
@@ -533,6 +599,12 @@ static bool fuse_request_queue_background(struct fuse_req *req)
 		atomic_inc(&fc->num_waiting);
 	}
 	__set_bit(FR_ISREPLY, &req->flags);
+
+#ifdef CONFIG_FUSE_IO_URING
+	if (fuse_uring_ready(fc))
+		return fuse_request_queue_background_uring(fc, req);
+#endif
+
 	spin_lock(&fc->bg_lock);
 	if (likely(fc->connected)) {
 		fc->num_background++;
@@ -560,7 +632,7 @@ int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
 		__set_bit(FR_BACKGROUND, &req->flags);
 	} else {
 		WARN_ON(args->nocreds);
-		req = fuse_get_req(fm, true);
+		req = fuse_get_req(&invalid_mnt_idmap, fm, true);
 		if (IS_ERR(req))
 			return PTR_ERR(req);
 	}
@@ -581,9 +653,8 @@ static int fuse_simple_notify_reply(struct fuse_mount *fm,
 {
 	struct fuse_req *req;
 	struct fuse_iqueue *fiq = &fm->fc->iq;
-	int err = 0;
 
-	req = fuse_get_req(fm, false);
+	req = fuse_get_req(&invalid_mnt_idmap, fm, false);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
@@ -592,16 +663,9 @@ static int fuse_simple_notify_reply(struct fuse_mount *fm,
 
 	fuse_args_to_req(req, args);
 
-	spin_lock(&fiq->lock);
-	if (fiq->connected) {
-		queue_request_and_unlock(fiq, req);
-	} else {
-		err = -ENODEV;
-		spin_unlock(&fiq->lock);
-		fuse_put_request(req);
-	}
+	fuse_send_one(fiq, req);
 
-	return err;
+	return 0;
 }
 
 /*
@@ -641,22 +705,8 @@ static int unlock_request(struct fuse_req *req)
 	return err;
 }
 
-struct fuse_copy_state {
-	int write;
-	struct fuse_req *req;
-	struct iov_iter *iter;
-	struct pipe_buffer *pipebufs;
-	struct pipe_buffer *currbuf;
-	struct pipe_inode_info *pipe;
-	unsigned long nr_segs;
-	struct page *pg;
-	unsigned len;
-	unsigned offset;
-	unsigned move_pages:1;
-};
-
-static void fuse_copy_init(struct fuse_copy_state *cs, int write,
-			   struct iov_iter *iter)
+void fuse_copy_init(struct fuse_copy_state *cs, int write,
+		    struct iov_iter *iter)
 {
 	memset(cs, 0, sizeof(*cs));
 	cs->write = write;
@@ -763,6 +813,9 @@ static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 	*size -= ncpy;
 	cs->len -= ncpy;
 	cs->offset += ncpy;
+	if (cs->is_uring)
+		cs->ring.copied_sz += ncpy;
+
 	return ncpy;
 }
 
@@ -773,7 +826,6 @@ static int fuse_check_folio(struct folio *folio)
 	    (folio->flags & PAGE_FLAGS_CHECK_AT_PREP &
 	     ~(1 << PG_locked |
 	       1 << PG_referenced |
-	       1 << PG_uptodate |
 	       1 << PG_lru |
 	       1 << PG_active |
 	       1 << PG_workingset |
@@ -786,6 +838,12 @@ static int fuse_check_folio(struct folio *folio)
 	return 0;
 }
 
+/*
+ * Attempt to steal a page from the splice() pipe and move it into the
+ * pagecache. If successful, the pointer in @pagep will be updated. The
+ * folio that was originally in @pagep will lose a reference and the new
+ * folio returned in @pagep will carry a reference.
+ */
 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 {
 	int err;
@@ -818,9 +876,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 
 	newfolio = page_folio(buf->page);
 
-	if (!folio_test_uptodate(newfolio))
-		folio_mark_uptodate(newfolio);
-
+	folio_clear_uptodate(newfolio);
 	folio_clear_mappedtodisk(newfolio);
 
 	if (fuse_check_folio(newfolio) != 0)
@@ -980,17 +1036,27 @@ static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 	struct fuse_req *req = cs->req;
 	struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
 
-
-	for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
+	for (i = 0; i < ap->num_folios && (nbytes || zeroing); i++) {
 		int err;
 		unsigned int offset = ap->descs[i].offset;
 		unsigned int count = min(nbytes, ap->descs[i].length);
+		struct page *orig, *pagep;
 
-		err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
+		orig = pagep = &ap->folios[i]->page;
+
+		err = fuse_copy_page(cs, &pagep, offset, count, zeroing);
 		if (err)
 			return err;
 
 		nbytes -= count;
+
+		/*
+		 *  fuse_copy_page may have moved a page from a pipe instead of
+		 *  copying into our given page, so update the folios if it was
+		 *  replaced.
+		 */
+		if (pagep != orig)
+			ap->folios[i] = page_folio(pagep);
 	}
 	return 0;
 }
@@ -1010,9 +1076,9 @@ static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
 }
 
 /* Copy request arguments to/from userspace buffer */
-static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
-			  unsigned argpages, struct fuse_arg *args,
-			  int zeroing)
+int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
+		   unsigned argpages, struct fuse_arg *args,
+		   int zeroing)
 {
 	int err = 0;
 	unsigned i;
@@ -1076,9 +1142,9 @@ __releases(fiq->lock)
 	return err ? err : reqsize;
 }
 
-struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
-					     unsigned int max,
-					     unsigned int *countp)
+static struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
+						    unsigned int max,
+						    unsigned int *countp)
 {
 	struct fuse_forget_link *head = fiq->forget_list_head.next;
 	struct fuse_forget_link **newhead = &head;
@@ -1097,7 +1163,6 @@ struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
 
 	return head;
 }
-EXPORT_SYMBOL(fuse_dequeue_forget);
 
 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
 				   struct fuse_copy_state *cs,
@@ -1112,7 +1177,7 @@ __releases(fiq->lock)
 	struct fuse_in_header ih = {
 		.opcode = FUSE_FORGET,
 		.nodeid = forget->forget_one.nodeid,
-		.unique = fuse_get_unique(fiq),
+		.unique = fuse_get_unique_locked(fiq),
 		.len = sizeof(ih) + sizeof(arg),
 	};
 
@@ -1143,7 +1208,7 @@ __releases(fiq->lock)
 	struct fuse_batch_forget_in arg = { .count = 0 };
 	struct fuse_in_header ih = {
 		.opcode = FUSE_BATCH_FORGET,
-		.unique = fuse_get_unique(fiq),
+		.unique = fuse_get_unique_locked(fiq),
 		.len = sizeof(ih) + sizeof(arg),
 	};
 
@@ -1392,7 +1457,7 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
 	if (ret < 0)
 		goto out;
 
-	if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) {
+	if (pipe_buf_usage(pipe) + cs.nr_segs > pipe->max_usage) {
 		ret = -EIO;
 		goto out;
 	}
@@ -1607,22 +1672,25 @@ static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
 
 	num = outarg.size;
 	while (num) {
+		struct folio *folio;
 		struct page *page;
 		unsigned int this_num;
 
-		err = -ENOMEM;
-		page = find_or_create_page(mapping, index,
-					   mapping_gfp_mask(mapping));
-		if (!page)
+		folio = filemap_grab_folio(mapping, index);
+		err = PTR_ERR(folio);
+		if (IS_ERR(folio))
 			goto out_iput;
 
-		this_num = min_t(unsigned, num, PAGE_SIZE - offset);
+		page = &folio->page;
+		this_num = min_t(unsigned, num, folio_size(folio) - offset);
 		err = fuse_copy_page(cs, &page, offset, this_num, 0);
-		if (!err && offset == 0 &&
-		    (this_num == PAGE_SIZE || file_size == end))
-			SetPageUptodate(page);
-		unlock_page(page);
-		put_page(page);
+		if (!folio_test_uptodate(folio) && !err && offset == 0 &&
+		    (this_num == folio_size(folio) || file_size == end)) {
+			folio_zero_segment(folio, this_num, folio_size(folio));
+			folio_mark_uptodate(folio);
+		}
+		folio_unlock(folio);
+		folio_put(folio);
 
 		if (err)
 			goto out_iput;
@@ -1654,7 +1722,7 @@ static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args,
 	struct fuse_retrieve_args *ra =
 		container_of(args, typeof(*ra), ap.args);
 
-	release_pages(ra->ap.pages, ra->ap.num_pages);
+	release_pages(ra->ap.folios, ra->ap.num_folios);
 	kfree(ra);
 }
 
@@ -1668,7 +1736,7 @@ static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
 	unsigned int num;
 	unsigned int offset;
 	size_t total_len = 0;
-	unsigned int num_pages;
+	unsigned int num_pages, cur_pages = 0;
 	struct fuse_conn *fc = fm->fc;
 	struct fuse_retrieve_args *ra;
 	size_t args_size = sizeof(*ra);
@@ -1687,38 +1755,39 @@ static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
 	num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	num_pages = min(num_pages, fc->max_pages);
 
-	args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
+	args_size += num_pages * (sizeof(ap->folios[0]) + sizeof(ap->descs[0]));
 
 	ra = kzalloc(args_size, GFP_KERNEL);
 	if (!ra)
 		return -ENOMEM;
 
 	ap = &ra->ap;
-	ap->pages = (void *) (ra + 1);
-	ap->descs = (void *) (ap->pages + num_pages);
+	ap->folios = (void *) (ra + 1);
+	ap->descs = (void *) (ap->folios + num_pages);
 
 	args = &ap->args;
 	args->nodeid = outarg->nodeid;
 	args->opcode = FUSE_NOTIFY_REPLY;
-	args->in_numargs = 2;
+	args->in_numargs = 3;
 	args->in_pages = true;
 	args->end = fuse_retrieve_end;
 
 	index = outarg->offset >> PAGE_SHIFT;
 
-	while (num && ap->num_pages < num_pages) {
-		struct page *page;
+	while (num && cur_pages < num_pages) {
+		struct folio *folio;
 		unsigned int this_num;
 
-		page = find_get_page(mapping, index);
-		if (!page)
+		folio = filemap_get_folio(mapping, index);
+		if (IS_ERR(folio))
 			break;
 
 		this_num = min_t(unsigned, num, PAGE_SIZE - offset);
-		ap->pages[ap->num_pages] = page;
-		ap->descs[ap->num_pages].offset = offset;
-		ap->descs[ap->num_pages].length = this_num;
-		ap->num_pages++;
+		ap->folios[ap->num_folios] = folio;
+		ap->descs[ap->num_folios].offset = offset;
+		ap->descs[ap->num_folios].length = this_num;
+		ap->num_folios++;
+		cur_pages++;
 
 		offset = 0;
 		num -= this_num;
@@ -1727,9 +1796,10 @@ static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
 	}
 	ra->inarg.offset = outarg->offset;
 	ra->inarg.size = total_len;
-	args->in_args[0].size = sizeof(ra->inarg);
-	args->in_args[0].value = &ra->inarg;
-	args->in_args[1].size = total_len;
+	fuse_set_zero_arg0(args);
+	args->in_args[1].size = sizeof(ra->inarg);
+	args->in_args[1].value = &ra->inarg;
+	args->in_args[2].size = total_len;
 
 	err = fuse_simple_notify_reply(fm, args, outarg->notify_unique);
 	if (err)
@@ -1775,6 +1845,69 @@ copy_finish:
 	return err;
 }
 
+/*
+ * Resending all processing queue requests.
+ *
+ * During a FUSE daemon panics and failover, it is possible for some inflight
+ * requests to be lost and never returned. As a result, applications awaiting
+ * replies would become stuck forever. To address this, we can use notification
+ * to trigger resending of these pending requests to the FUSE daemon, ensuring
+ * they are properly processed again.
+ *
+ * Please note that this strategy is applicable only to idempotent requests or
+ * if the FUSE daemon takes careful measures to avoid processing duplicated
+ * non-idempotent requests.
+ */
+static void fuse_resend(struct fuse_conn *fc)
+{
+	struct fuse_dev *fud;
+	struct fuse_req *req, *next;
+	struct fuse_iqueue *fiq = &fc->iq;
+	LIST_HEAD(to_queue);
+	unsigned int i;
+
+	spin_lock(&fc->lock);
+	if (!fc->connected) {
+		spin_unlock(&fc->lock);
+		return;
+	}
+
+	list_for_each_entry(fud, &fc->devices, entry) {
+		struct fuse_pqueue *fpq = &fud->pq;
+
+		spin_lock(&fpq->lock);
+		for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
+			list_splice_tail_init(&fpq->processing[i], &to_queue);
+		spin_unlock(&fpq->lock);
+	}
+	spin_unlock(&fc->lock);
+
+	list_for_each_entry_safe(req, next, &to_queue, list) {
+		set_bit(FR_PENDING, &req->flags);
+		clear_bit(FR_SENT, &req->flags);
+		/* mark the request as resend request */
+		req->in.h.unique |= FUSE_UNIQUE_RESEND;
+	}
+
+	spin_lock(&fiq->lock);
+	if (!fiq->connected) {
+		spin_unlock(&fiq->lock);
+		list_for_each_entry(req, &to_queue, list)
+			clear_bit(FR_PENDING, &req->flags);
+		fuse_dev_end_requests(&to_queue);
+		return;
+	}
+	/* iq and pq requests are both oldest to newest */
+	list_splice(&to_queue, &fiq->pending);
+	fuse_dev_wake_and_unlock(fiq);
+}
+
+static int fuse_notify_resend(struct fuse_conn *fc)
+{
+	fuse_resend(fc);
+	return 0;
+}
+
 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
 		       unsigned int size, struct fuse_copy_state *cs)
 {
@@ -1800,6 +1933,9 @@ static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
 	case FUSE_NOTIFY_DELETE:
 		return fuse_notify_delete(fc, size, cs);
 
+	case FUSE_NOTIFY_RESEND:
+		return fuse_notify_resend(fc);
+
 	default:
 		fuse_copy_finish(cs);
 		return -EINVAL;
@@ -1807,7 +1943,7 @@ static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
 }
 
 /* Look up request on processing list by unique ID */
-static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
+struct fuse_req *fuse_request_find(struct fuse_pqueue *fpq, u64 unique)
 {
 	unsigned int hash = fuse_req_hash(unique);
 	struct fuse_req *req;
@@ -1819,10 +1955,17 @@ static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
 	return NULL;
 }
 
-static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
-			 unsigned nbytes)
+int fuse_copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
+		       unsigned nbytes)
 {
-	unsigned reqsize = sizeof(struct fuse_out_header);
+
+	unsigned int reqsize = 0;
+
+	/*
+	 * Uring has all headers separated from args - args is payload only
+	 */
+	if (!cs->is_uring)
+		reqsize = sizeof(struct fuse_out_header);
 
 	reqsize += fuse_len_args(args->out_numargs, args->out_args);
 
@@ -1884,7 +2027,7 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
 	spin_lock(&fpq->lock);
 	req = NULL;
 	if (fpq->connected)
-		req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
+		req = fuse_request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
 
 	err = -ENOENT;
 	if (!req) {
@@ -1922,7 +2065,7 @@ static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
 	if (oh.error)
 		err = nbytes != sizeof(oh) ? -EINVAL : 0;
 	else
-		err = copy_out_args(cs, req->args, nbytes);
+		err = fuse_copy_out_args(cs, req->args, nbytes);
 	fuse_copy_finish(cs);
 
 	spin_lock(&fpq->lock);
@@ -1964,7 +2107,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 				     struct file *out, loff_t *ppos,
 				     size_t len, unsigned int flags)
 {
-	unsigned int head, tail, mask, count;
+	unsigned int head, tail, count;
 	unsigned nbuf;
 	unsigned idx;
 	struct pipe_buffer *bufs;
@@ -1981,8 +2124,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 
 	head = pipe->head;
 	tail = pipe->tail;
-	mask = pipe->ring_size - 1;
-	count = head - tail;
+	count = pipe_occupancy(head, tail);
 
 	bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL);
 	if (!bufs) {
@@ -1992,8 +2134,8 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 
 	nbuf = 0;
 	rem = 0;
-	for (idx = tail; idx != head && rem < len; idx++)
-		rem += pipe->bufs[idx & mask].len;
+	for (idx = tail; !pipe_empty(head, idx) && rem < len; idx++)
+		rem += pipe_buf(pipe, idx)->len;
 
 	ret = -EINVAL;
 	if (rem < len)
@@ -2004,10 +2146,10 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 		struct pipe_buffer *ibuf;
 		struct pipe_buffer *obuf;
 
-		if (WARN_ON(nbuf >= count || tail == head))
+		if (WARN_ON(nbuf >= count || pipe_empty(head, tail)))
 			goto out_free;
 
-		ibuf = &pipe->bufs[tail & mask];
+		ibuf = pipe_buf(pipe, tail);
 		obuf = &bufs[nbuf];
 
 		if (rem >= ibuf->len) {
@@ -2077,7 +2219,7 @@ static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
 }
 
 /* Abort all requests on the given list (pending or processing) */
-static void end_requests(struct list_head *head)
+void fuse_dev_end_requests(struct list_head *head)
 {
 	while (!list_empty(head)) {
 		struct fuse_req *req;
@@ -2180,7 +2322,13 @@ void fuse_abort_conn(struct fuse_conn *fc)
 		wake_up_all(&fc->blocked_waitq);
 		spin_unlock(&fc->lock);
 
-		end_requests(&to_end);
+		fuse_dev_end_requests(&to_end);
+
+		/*
+		 * fc->lock must not be taken to avoid conflicts with io-uring
+		 * locks
+		 */
+		fuse_uring_abort(fc);
 	} else {
 		spin_unlock(&fc->lock);
 	}
@@ -2192,6 +2340,8 @@ void fuse_wait_aborted(struct fuse_conn *fc)
 	/* matches implicit memory barrier in fuse_drop_waiting() */
 	smp_mb();
 	wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
+
+	fuse_uring_wait_stopped_queues(fc);
 }
 
 int fuse_dev_release(struct inode *inode, struct file *file)
@@ -2210,7 +2360,7 @@ int fuse_dev_release(struct inode *inode, struct file *file)
 			list_splice_init(&fpq->processing[i], &to_end);
 		spin_unlock(&fpq->lock);
 
-		end_requests(&to_end);
+		fuse_dev_end_requests(&to_end);
 
 		/* Are we the last open device? */
 		if (atomic_dec_and_test(&fc->dev_count)) {
@@ -2251,49 +2401,94 @@ static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
 	return 0;
 }
 
-static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
-			   unsigned long arg)
+static long fuse_dev_ioctl_clone(struct file *file, __u32 __user *argp)
 {
 	int res;
 	int oldfd;
 	struct fuse_dev *fud = NULL;
-	struct fd f;
+
+	if (get_user(oldfd, argp))
+		return -EFAULT;
+
+	CLASS(fd, f)(oldfd);
+	if (fd_empty(f))
+		return -EINVAL;
+
+	/*
+	 * Check against file->f_op because CUSE
+	 * uses the same ioctl handler.
+	 */
+	if (fd_file(f)->f_op == file->f_op)
+		fud = fuse_get_dev(fd_file(f));
+
+	res = -EINVAL;
+	if (fud) {
+		mutex_lock(&fuse_mutex);
+		res = fuse_device_clone(fud->fc, file);
+		mutex_unlock(&fuse_mutex);
+	}
+
+	return res;
+}
+
+static long fuse_dev_ioctl_backing_open(struct file *file,
+					struct fuse_backing_map __user *argp)
+{
+	struct fuse_dev *fud = fuse_get_dev(file);
+	struct fuse_backing_map map;
+
+	if (!fud)
+		return -EPERM;
+
+	if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
+		return -EOPNOTSUPP;
+
+	if (copy_from_user(&map, argp, sizeof(map)))
+		return -EFAULT;
+
+	return fuse_backing_open(fud->fc, &map);
+}
+
+static long fuse_dev_ioctl_backing_close(struct file *file, __u32 __user *argp)
+{
+	struct fuse_dev *fud = fuse_get_dev(file);
+	int backing_id;
+
+	if (!fud)
+		return -EPERM;
+
+	if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
+		return -EOPNOTSUPP;
+
+	if (get_user(backing_id, argp))
+		return -EFAULT;
+
+	return fuse_backing_close(fud->fc, backing_id);
+}
+
+static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
 
 	switch (cmd) {
 	case FUSE_DEV_IOC_CLONE:
-		if (get_user(oldfd, (__u32 __user *)arg))
-			return -EFAULT;
+		return fuse_dev_ioctl_clone(file, argp);
 
-		f = fdget(oldfd);
-		if (!f.file)
-			return -EINVAL;
+	case FUSE_DEV_IOC_BACKING_OPEN:
+		return fuse_dev_ioctl_backing_open(file, argp);
+
+	case FUSE_DEV_IOC_BACKING_CLOSE:
+		return fuse_dev_ioctl_backing_close(file, argp);
 
-		/*
-		 * Check against file->f_op because CUSE
-		 * uses the same ioctl handler.
-		 */
-		if (f.file->f_op == file->f_op)
-			fud = fuse_get_dev(f.file);
-
-		res = -EINVAL;
-		if (fud) {
-			mutex_lock(&fuse_mutex);
-			res = fuse_device_clone(fud->fc, file);
-			mutex_unlock(&fuse_mutex);
-		}
-		fdput(f);
-		break;
 	default:
-		res = -ENOTTY;
-		break;
+		return -ENOTTY;
 	}
-	return res;
 }
 
 const struct file_operations fuse_dev_operations = {
 	.owner		= THIS_MODULE,
 	.open		= fuse_dev_open,
-	.llseek		= no_llseek,
 	.read_iter	= fuse_dev_read,
 	.splice_read	= fuse_dev_splice_read,
 	.write_iter	= fuse_dev_write,
@@ -2303,6 +2498,9 @@ const struct file_operations fuse_dev_operations = {
 	.fasync		= fuse_dev_fasync,
 	.unlocked_ioctl = fuse_dev_ioctl,
 	.compat_ioctl   = compat_ptr_ioctl,
+#ifdef CONFIG_FUSE_IO_URING
+	.uring_cmd	= fuse_uring_cmd,
+#endif
 };
 EXPORT_SYMBOL_GPL(fuse_dev_operations);