[PATCH 7.0 250/461] netfs: Fix cancellation of a DIO and single read subrequests

[PATCH 7.0 250/461] netfs: Fix cancellation of a DIO and single read subrequests

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 6f0f7ac1915abc0d202f0eb4b003a6548a5ba60d ]

When the preparation of a new subrequest for a read fails, if the
subrequest has already been added to the stream->subrequests list, it can't
simply be put and abandoned as the collector may see it.  Also, if it
hasn't been queued yet, it has two outstanding refs that both need to be
put.  Both DIO read and single-read dispatch fail at this; further, both
differ in the order they do things to the way buffered read works.

Fix cancellation of both DIO-read and single-read subrequests that failed
preparation by the following steps:

 (1) Harmonise all three reads (buffered, dio, single) to queue the subreq
     before prepping it.

 (2) Make all three call netfs_queue_read() to do the queuing.

 (3) Set NETFS_RREQ_ALL_QUEUED independently of the queuing as we don't
     know the length of the subreq at this point.

 (4) In all cases, set the error and NETFS_SREQ_FAILED flag on the subreq
     and then call netfs_read_subreq_terminated() to deal with it.  This
     will pass responsibility off to the collector for dealing with it.

Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Closes: https://sashiko.dev/#/patchset/20260425125426.3855807-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-2-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_read.c | 34 +++++++++++++-------------------
 fs/netfs/direct_read.c   | 42 +++++++++++++---------------------------
 fs/netfs/internal.h      |  3 +++
 fs/netfs/read_collect.c  | 11 +++++++++++
 fs/netfs/read_single.c   | 23 ++++++++++------------
 5 files changed, 50 insertions(+), 63 deletions(-)

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index a8c0d86118c58..a27ed501b6d43 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -156,9 +156,8 @@ static void netfs_read_cache_to_pagecache(struct netfs_io_request *rreq,
 			netfs_cache_read_terminated, subreq);
 }
 
-static void netfs_queue_read(struct netfs_io_request *rreq,
-			     struct netfs_io_subrequest *subreq,
-			     bool last_subreq)
+void netfs_queue_read(struct netfs_io_request *rreq,
+		      struct netfs_io_subrequest *subreq)
 {
 	struct netfs_io_stream *stream = &rreq->io_streams[0];
 
@@ -178,11 +177,6 @@ static void netfs_queue_read(struct netfs_io_request *rreq,
 		}
 	}
 
-	if (last_subreq) {
-		smp_wmb(); /* Write lists before ALL_QUEUED. */
-		set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags);
-	}
-
 	spin_unlock(&rreq->lock);
 }
 
@@ -233,6 +227,8 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq,
 		subreq->start	= start;
 		subreq->len	= size;
 
+		netfs_queue_read(rreq, subreq);
+
 		source = netfs_cache_prepare_read(rreq, subreq, rreq->i_size);
 		subreq->source = source;
 		if (source == NETFS_DOWNLOAD_FROM_SERVER) {
@@ -253,6 +249,7 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq,
 				       rreq->debug_id, subreq->debug_index,
 				       subreq->len, size,
 				       subreq->start, ictx->zero_point, rreq->i_size);
+				netfs_cancel_read(subreq, ret);
 				break;
 			}
 			subreq->len = len;
@@ -261,12 +258,7 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq,
 			if (rreq->netfs_ops->prepare_read) {
 				ret = rreq->netfs_ops->prepare_read(subreq);
 				if (ret < 0) {
-					subreq->error = ret;
-					/* Not queued - release both refs. */
-					netfs_put_subrequest(subreq,
-							     netfs_sreq_trace_put_cancel);
-					netfs_put_subrequest(subreq,
-							     netfs_sreq_trace_put_cancel);
+					netfs_cancel_read(subreq, ret);
 					break;
 				}
 				trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
@@ -289,23 +281,23 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq,
 
 		pr_err("Unexpected read source %u\n", source);
 		WARN_ON_ONCE(1);
+		netfs_cancel_read(subreq, ret);
 		break;
 
 	issue:
 		slice = netfs_prepare_read_iterator(subreq, ractl);
 		if (slice < 0) {
 			ret = slice;
-			subreq->error = ret;
-			trace_netfs_sreq(subreq, netfs_sreq_trace_cancel);
-			/* Not queued - release both refs. */
-			netfs_put_subrequest(subreq, netfs_sreq_trace_put_cancel);
-			netfs_put_subrequest(subreq, netfs_sreq_trace_put_cancel);
+			netfs_cancel_read(subreq, ret);
 			break;
 		}
-		size -= slice;
 		start += slice;
+		size -= slice;
+		if (size <= 0) {
+			smp_wmb(); /* Write lists before ALL_QUEUED. */
+			set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags);
+		}
 
-		netfs_queue_read(rreq, subreq, size <= 0);
 		netfs_issue_read(rreq, subreq);
 		cond_resched();
 	} while (size > 0);
diff --git a/fs/netfs/direct_read.c b/fs/netfs/direct_read.c
index f72e6da88cca7..6a8fb0d55e040 100644
--- a/fs/netfs/direct_read.c
+++ b/fs/netfs/direct_read.c
@@ -45,12 +45,11 @@ static void netfs_prepare_dio_read_iterator(struct netfs_io_subrequest *subreq)
  * Perform a read to a buffer from the server, slicing up the region to be read
  * according to the network rsize.
  */
-static int netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq)
+static void netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq)
 {
-	struct netfs_io_stream *stream = &rreq->io_streams[0];
 	unsigned long long start = rreq->start;
 	ssize_t size = rreq->len;
-	int ret = 0;
+	int ret;
 
 	do {
 		struct netfs_io_subrequest *subreq;
@@ -58,7 +57,10 @@ static int netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq)
 
 		subreq = netfs_alloc_subrequest(rreq);
 		if (!subreq) {
-			ret = -ENOMEM;
+			/* Stash the error in the request if there's not
+			 * already an error set.
+			 */
+			cmpxchg(&rreq->error, 0, -ENOMEM);
 			break;
 		}
 
@@ -66,25 +68,13 @@ static int netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq)
 		subreq->start	= start;
 		subreq->len	= size;
 
-		__set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
-
-		spin_lock(&rreq->lock);
-		list_add_tail(&subreq->rreq_link, &stream->subrequests);
-		if (list_is_first(&subreq->rreq_link, &stream->subrequests)) {
-			if (!stream->active) {
-				stream->collected_to = subreq->start;
-				/* Store list pointers before active flag */
-				smp_store_release(&stream->active, true);
-			}
-		}
-		trace_netfs_sreq(subreq, netfs_sreq_trace_added);
-		spin_unlock(&rreq->lock);
+		netfs_queue_read(rreq, subreq);
 
 		netfs_stat(&netfs_n_rh_download);
 		if (rreq->netfs_ops->prepare_read) {
 			ret = rreq->netfs_ops->prepare_read(subreq);
 			if (ret < 0) {
-				netfs_put_subrequest(subreq, netfs_sreq_trace_put_cancel);
+				netfs_cancel_read(subreq, ret);
 				break;
 			}
 		}
@@ -113,8 +103,6 @@ static int netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq)
 		set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags);
 		netfs_wake_collector(rreq);
 	}
-
-	return ret;
 }
 
 /*
@@ -137,21 +125,17 @@ static ssize_t netfs_unbuffered_read(struct netfs_io_request *rreq, bool sync)
 	// TODO: Use bounce buffer if requested
 
 	inode_dio_begin(rreq->inode);
+	netfs_dispatch_unbuffered_reads(rreq);
 
-	ret = netfs_dispatch_unbuffered_reads(rreq);
-
-	if (!rreq->submitted) {
-		netfs_put_request(rreq, netfs_rreq_trace_put_no_submit);
-		inode_dio_end(rreq->inode);
-		ret = 0;
-		goto out;
-	}
+	/* The collector will get run, even if we don't manage to submit any
+	 * subreqs, so we shouldn't call inode_dio_end() here.
+	 */
 
 	if (sync)
 		ret = netfs_wait_for_read(rreq);
 	else
 		ret = -EIOCBQUEUED;
-out:
+
 	_leave(" = %zd", ret);
 	return ret;
 }
diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h
index d436e20d34185..645996ecfc803 100644
--- a/fs/netfs/internal.h
+++ b/fs/netfs/internal.h
@@ -23,6 +23,8 @@
 /*
  * buffered_read.c
  */
+void netfs_queue_read(struct netfs_io_request *rreq,
+		      struct netfs_io_subrequest *subreq);
 void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error);
 int netfs_prefetch_for_write(struct file *file, struct folio *folio,
 			     size_t offset, size_t len);
@@ -108,6 +110,7 @@ static inline void netfs_see_subrequest(struct netfs_io_subrequest *subreq,
  */
 bool netfs_read_collection(struct netfs_io_request *rreq);
 void netfs_read_collection_worker(struct work_struct *work);
+void netfs_cancel_read(struct netfs_io_subrequest *subreq, int error);
 void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error);
 
 /*
diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c
index e5f6665b3341e..d2d902f466271 100644
--- a/fs/netfs/read_collect.c
+++ b/fs/netfs/read_collect.c
@@ -575,6 +575,17 @@ void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq)
 }
 EXPORT_SYMBOL(netfs_read_subreq_terminated);
 
+/*
+ * Cancel a read subrequest due to preparation failure.
+ */
+void netfs_cancel_read(struct netfs_io_subrequest *subreq, int error)
+{
+	trace_netfs_sreq(subreq, netfs_sreq_trace_cancel);
+	subreq->error = error;
+	__set_bit(NETFS_SREQ_FAILED, &subreq->flags);
+	netfs_read_subreq_terminated(subreq);
+}
+
 /*
  * Handle termination of a read from the cache.
  */
diff --git a/fs/netfs/read_single.c b/fs/netfs/read_single.c
index d0e23bc42445f..8833550d2eb60 100644
--- a/fs/netfs/read_single.c
+++ b/fs/netfs/read_single.c
@@ -89,7 +89,6 @@ static void netfs_single_read_cache(struct netfs_io_request *rreq,
  */
 static int netfs_single_dispatch_read(struct netfs_io_request *rreq)
 {
-	struct netfs_io_stream *stream = &rreq->io_streams[0];
 	struct netfs_io_subrequest *subreq;
 	int ret = 0;
 
@@ -102,14 +101,7 @@ static int netfs_single_dispatch_read(struct netfs_io_request *rreq)
 	subreq->len	= rreq->len;
 	subreq->io_iter	= rreq->buffer.iter;
 
-	__set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
-
-	spin_lock(&rreq->lock);
-	list_add_tail(&subreq->rreq_link, &stream->subrequests);
-	trace_netfs_sreq(subreq, netfs_sreq_trace_added);
-	/* Store list pointers before active flag */
-	smp_store_release(&stream->active, true);
-	spin_unlock(&rreq->lock);
+	netfs_queue_read(rreq, subreq);
 
 	netfs_single_cache_prepare_read(rreq, subreq);
 	switch (subreq->source) {
@@ -121,10 +113,14 @@ static int netfs_single_dispatch_read(struct netfs_io_request *rreq)
 				goto cancel;
 		}
 
+		smp_wmb(); /* Write lists before ALL_QUEUED. */
+		set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags);
 		rreq->netfs_ops->issue_read(subreq);
 		rreq->submitted += subreq->len;
 		break;
 	case NETFS_READ_FROM_CACHE:
+		smp_wmb(); /* Write lists before ALL_QUEUED. */
+		set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags);
 		trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
 		netfs_single_read_cache(rreq, subreq);
 		rreq->submitted += subreq->len;
@@ -134,14 +130,15 @@ static int netfs_single_dispatch_read(struct netfs_io_request *rreq)
 		pr_warn("Unexpected single-read source %u\n", subreq->source);
 		WARN_ON_ONCE(true);
 		ret = -EIO;
-		break;
+		goto cancel;
 	}
 
-	smp_wmb(); /* Write lists before ALL_QUEUED. */
-	set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags);
 	return ret;
 cancel:
-	netfs_put_subrequest(subreq, netfs_sreq_trace_put_cancel);
+	netfs_cancel_read(subreq, ret);
+	smp_wmb(); /* Write lists before ALL_QUEUED. */
+	set_bit(NETFS_RREQ_ALL_QUEUED, &rreq->flags);
+	netfs_wake_collector(rreq);
 	return ret;
 }
 
-- 
2.53.0

[PATCH 7.0 251/461] netfs: Fix missing locking around retry adding new subreqs

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit cce18c263e9623872327ba3c956012f73c1179cc ]

Fix netfs_retry_read_subrequests() and netfs_retry_write_stream() to take
the appropriate lock when adding extra subrequests into
stream->subrequests.

Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Fixes: 288ace2f57c9 ("netfs: New writeback implementation")
Closes: https://sashiko.dev/#/patchset/20260425125426.3855807-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-3-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/read_retry.c  | 6 +++++-
 fs/netfs/write_retry.c | 6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c
index cca9ac43c0773..5ec548b996d65 100644
--- a/fs/netfs/read_retry.c
+++ b/fs/netfs/read_retry.c
@@ -175,7 +175,9 @@ static void netfs_retry_read_subrequests(struct netfs_io_request *rreq)
 			list_for_each_entry_safe_from(subreq, tmp,
 						      &stream->subrequests, rreq_link) {
 				trace_netfs_sreq(subreq, netfs_sreq_trace_superfluous);
+				spin_lock(&rreq->lock);
 				list_del(&subreq->rreq_link);
+				spin_unlock(&rreq->lock);
 				netfs_put_subrequest(subreq, netfs_sreq_trace_put_done);
 				if (subreq == to)
 					break;
@@ -203,8 +205,10 @@ static void netfs_retry_read_subrequests(struct netfs_io_request *rreq)
 					     refcount_read(&subreq->ref),
 					     netfs_sreq_trace_new);
 
+			spin_lock(&rreq->lock);
 			list_add(&subreq->rreq_link, &to->rreq_link);
-			to = list_next_entry(to, rreq_link);
+			spin_unlock(&rreq->lock);
+			to = subreq;
 			trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
 
 			stream->sreq_max_len	= umin(len, rreq->rsize);
diff --git a/fs/netfs/write_retry.c b/fs/netfs/write_retry.c
index 29489a23a2209..32735abfa03f0 100644
--- a/fs/netfs/write_retry.c
+++ b/fs/netfs/write_retry.c
@@ -130,7 +130,9 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq,
 			list_for_each_entry_safe_from(subreq, tmp,
 						      &stream->subrequests, rreq_link) {
 				trace_netfs_sreq(subreq, netfs_sreq_trace_discard);
+				spin_lock(&wreq->lock);
 				list_del(&subreq->rreq_link);
+				spin_unlock(&wreq->lock);
 				netfs_put_subrequest(subreq, netfs_sreq_trace_put_done);
 				if (subreq == to)
 					break;
@@ -153,8 +155,10 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq,
 					     netfs_sreq_trace_new);
 			trace_netfs_sreq(subreq, netfs_sreq_trace_split);
 
+			spin_lock(&wreq->lock);
 			list_add(&subreq->rreq_link, &to->rreq_link);
-			to = list_next_entry(to, rreq_link);
+			spin_unlock(&wreq->lock);
+			to = subreq;
 			trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
 
 			stream->sreq_max_len	= len;
-- 
2.53.0

[PATCH 7.0 252/461] netfs: Fix missing barriers when accessing stream->subrequests locklessly

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit b5782e2d462c028096f922abca46318cec890670 ]

The list of subrequests attached to stream->subrequests is accessed without
locks by netfs_collect_read_results() and netfs_collect_write_results(),
and then they access subreq->flags without taking a barrier after getting
the subreq pointer from the list.  Relatedly, the functions that build the
list don't use any sort of write barrier when constructing the list to make
sure that the NETFS_SREQ_IN_PROGRESS flag is perceived to be set first if
no lock is taken.

Fix this by:

 (1) Add a new list_add_tail_release() function that uses a release barrier
     to set the pointer to the new member of the list.

 (2) Add a new list_first_entry_or_null_acquire() function that uses an
     acquire barrier to read the pointer to the first member in a list (or
     return NULL).

 (3) Use list_add_tail_release() when adding a subreq to ->subrequests.

 (4) Use list_first_entry_or_null_acquire() when initially accessing the
     front of the list (when an item is removed, the pointer to the new
     front iterm is obtained under the same lock).

Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Fixes: 288ace2f57c9 ("netfs: New writeback implementation")
Link: https://sashiko.dev/#/patchset/20260326104544.509518-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-4-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_read.c |  3 ++-
 fs/netfs/misc.c          |  1 +
 fs/netfs/read_collect.c  |  6 ++++--
 fs/netfs/write_collect.c |  6 ++++--
 fs/netfs/write_issue.c   |  3 ++-
 include/linux/list.h     | 37 +++++++++++++++++++++++++++++++++++++
 6 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index a27ed501b6d43..15d73026ff643 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -168,7 +168,8 @@ void netfs_queue_read(struct netfs_io_request *rreq,
 	 * remove entries off of the front.
 	 */
 	spin_lock(&rreq->lock);
-	list_add_tail(&subreq->rreq_link, &stream->subrequests);
+	/* Write IN_PROGRESS before pointer to new subreq */
+	list_add_tail_release(&subreq->rreq_link, &stream->subrequests);
 	if (list_is_first(&subreq->rreq_link, &stream->subrequests)) {
 		if (!stream->active) {
 			stream->collected_to = subreq->start;
diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c
index 6df89c92b10b0..21357907b7eee 100644
--- a/fs/netfs/misc.c
+++ b/fs/netfs/misc.c
@@ -356,6 +356,7 @@ void netfs_wait_for_in_progress_stream(struct netfs_io_request *rreq,
 	DEFINE_WAIT(myself);
 
 	list_for_each_entry(subreq, &stream->subrequests, rreq_link) {
+		smp_rmb(); /* Read ->next before IN_PROGRESS. */
 		if (!netfs_check_subreq_in_progress(subreq))
 			continue;
 
diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c
index d2d902f466271..3c9b847885c2a 100644
--- a/fs/netfs/read_collect.c
+++ b/fs/netfs/read_collect.c
@@ -205,8 +205,10 @@ static void netfs_collect_read_results(struct netfs_io_request *rreq)
 	 * in progress.  The issuer thread may be adding stuff to the tail
 	 * whilst we're doing this.
 	 */
-	front = list_first_entry_or_null(&stream->subrequests,
-					 struct netfs_io_subrequest, rreq_link);
+	front = list_first_entry_or_null_acquire(&stream->subrequests,
+						 struct netfs_io_subrequest, rreq_link);
+	/* Read first subreq pointer before IN_PROGRESS flag. */
+
 	while (front) {
 		size_t transferred;
 
diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c
index b194447f4b111..7fbf50907a7fc 100644
--- a/fs/netfs/write_collect.c
+++ b/fs/netfs/write_collect.c
@@ -228,8 +228,10 @@ static void netfs_collect_write_results(struct netfs_io_request *wreq)
 		if (!smp_load_acquire(&stream->active))
 			continue;
 
-		front = list_first_entry_or_null(&stream->subrequests,
-						 struct netfs_io_subrequest, rreq_link);
+		front = list_first_entry_or_null_acquire(&stream->subrequests,
+							 struct netfs_io_subrequest, rreq_link);
+		/* Read first subreq pointer before IN_PROGRESS flag. */
+
 		while (front) {
 			trace_netfs_collect_sreq(wreq, front);
 			//_debug("sreq [%x] %llx %zx/%zx",
diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
index 2db688f941251..b0e9690bb90ce 100644
--- a/fs/netfs/write_issue.c
+++ b/fs/netfs/write_issue.c
@@ -204,7 +204,8 @@ void netfs_prepare_write(struct netfs_io_request *wreq,
 	 * remove entries off of the front.
 	 */
 	spin_lock(&wreq->lock);
-	list_add_tail(&subreq->rreq_link, &stream->subrequests);
+	/* Write IN_PROGRESS before pointer to new subreq */
+	list_add_tail_release(&subreq->rreq_link, &stream->subrequests);
 	if (list_is_first(&subreq->rreq_link, &stream->subrequests)) {
 		if (!stream->active) {
 			stream->collected_to = subreq->start;
diff --git a/include/linux/list.h b/include/linux/list.h
index 00ea8e5fb88b0..09d979976b3b8 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -191,6 +191,29 @@ static inline void list_add_tail(struct list_head *new, struct list_head *head)
 	__list_add(new, head->prev, head);
 }
 
+/**
+ * list_add_tail_release - add a new entry with release barrier
+ * @new: new entry to be added
+ * @head: list head to add it before
+ *
+ * Insert a new entry before the specified head, using a release barrier to set
+ * the ->next pointer that points to it.  This is useful for implementing
+ * queues, in particular one that the elements will be walked through forwards
+ * locklessly.
+ */
+static inline void list_add_tail_release(struct list_head *new,
+					 struct list_head *head)
+{
+	struct list_head *prev = head->prev;
+
+	if (__list_add_valid(new, prev, head)) {
+		new->next = head;
+		new->prev = prev;
+		head->prev = new;
+		smp_store_release(&prev->next, new);
+	}
+}
+
 /*
  * Delete a list entry by making the prev/next entries
  * point to each other.
@@ -644,6 +667,20 @@ static inline void list_splice_tail_init(struct list_head *list,
 	pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
 })
 
+/**
+ * list_first_entry_or_null_acquire - get the first element from a list with barrier
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Note that if the list is empty, it returns NULL.
+ */
+#define list_first_entry_or_null_acquire(ptr, type, member) ({ \
+	struct list_head *head__ = (ptr); \
+	struct list_head *pos__ = smp_load_acquire(&head__->next); \
+	pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
+})
+
 /**
  * list_last_entry_or_null - get the last element from a list
  * @ptr:	the list head to take the element from.
-- 
2.53.0

[PATCH 7.0 253/461] netfs: Fix netfs_read_to_pagecache() to pause on subreq failure

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 8a8c0cfdf4658fc5b295b7fc87be56e0d76741f4 ]

Fix netfs_read_to_pagecache() so that it pauses the generation of new
subrequests if an already-issued subrequest fails.

Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Closes: https://sashiko.dev/#/patchset/20260425125426.3855807-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-5-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_read.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 15d73026ff643..fee0aebf5a3d6 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -300,6 +300,11 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq,
 		}
 
 		netfs_issue_read(rreq, subreq);
+
+		if (test_bit(NETFS_RREQ_PAUSE, &rreq->flags))
+			netfs_wait_for_paused_read(rreq);
+		if (test_bit(NETFS_RREQ_FAILED, &rreq->flags))
+			break;
 		cond_resched();
 	} while (size > 0);
 
-- 
2.53.0

[PATCH 7.0 254/461] netfs: Fix potential for tearing in ->remote_i_size and ->zero_point

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 2c8f4742bb76117d735f92a3932d85239b16c494 ]

Fix potential tearing in using ->remote_i_size and ->zero_point by copying
i_size_read() and i_size_write() and using the same seqcount as for i_size.

We need to make sure that netfslib and the filesystems that use it always
hold i_lock whilst updating any of the sizes to prevent i_size_seqcount
from getting corrupted.

Fixes: 4058f742105e ("netfs: Keep track of the actual remote file size")
Fixes: 100ccd18bb41 ("netfs: Optimise away reads above the point at which there can be no data")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-6-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/9p/v9fs_vfs.h          |  13 --
 fs/9p/vfs_inode.c         |   6 +-
 fs/9p/vfs_inode_dotl.c    |  12 +-
 fs/afs/file.c             |  24 +++-
 fs/afs/inode.c            |  31 ++--
 fs/afs/internal.h         |  11 +-
 fs/afs/write.c            |   2 +-
 fs/netfs/buffered_read.c  |   6 +-
 fs/netfs/buffered_write.c |   2 +-
 fs/netfs/direct_write.c   |   6 +-
 fs/netfs/misc.c           |  32 +++--
 fs/netfs/write_collect.c  |   9 +-
 fs/smb/client/cifsfs.c    |  38 +++--
 fs/smb/client/cifssmb.c   |   3 +-
 fs/smb/client/file.c      |  13 +-
 fs/smb/client/inode.c     |  14 +-
 fs/smb/client/readdir.c   |   3 +-
 fs/smb/client/smb2ops.c   |  42 +++---
 fs/smb/client/smb2pdu.c   |   3 +-
 include/linux/netfs.h     | 293 ++++++++++++++++++++++++++++++++++++--
 20 files changed, 450 insertions(+), 113 deletions(-)

diff --git a/fs/9p/v9fs_vfs.h b/fs/9p/v9fs_vfs.h
index d3aefbec4de6e..34c115d7c2502 100644
--- a/fs/9p/v9fs_vfs.h
+++ b/fs/9p/v9fs_vfs.h
@@ -75,17 +75,4 @@ static inline void v9fs_invalidate_inode_attr(struct inode *inode)
 
 int v9fs_open_to_dotl_flags(int flags);
 
-static inline void v9fs_i_size_write(struct inode *inode, loff_t i_size)
-{
-	/*
-	 * 32-bit need the lock, concurrent updates could break the
-	 * sequences and make i_size_read() loop forever.
-	 * 64-bit updates are atomic and can skip the locking.
-	 */
-	if (sizeof(i_size) > sizeof(long))
-		spin_lock(&inode->i_lock);
-	i_size_write(inode, i_size);
-	if (sizeof(i_size) > sizeof(long))
-		spin_unlock(&inode->i_lock);
-}
 #endif
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 97abe65bf7c1f..a0a5aec8e5d53 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -1141,11 +1141,13 @@ v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 	mode |= inode->i_mode & ~S_IALLUGO;
 	inode->i_mode = mode;
 
-	v9inode->netfs.remote_i_size = stat->length;
+	spin_lock(&inode->i_lock);
+	netfs_write_remote_i_size(inode, stat->length);
 	if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
-		v9fs_i_size_write(inode, stat->length);
+		i_size_write(inode, stat->length);
 	/* not real number of blocks, but 512 byte ones ... */
 	inode->i_blocks = (stat->length + 512 - 1) >> 9;
+	spin_unlock(&inode->i_lock);
 	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
 }
 
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 643e759eacb2a..d800f4fad555c 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -634,10 +634,12 @@ v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
 		mode |= inode->i_mode & ~S_IALLUGO;
 		inode->i_mode = mode;
 
-		v9inode->netfs.remote_i_size = stat->st_size;
+		spin_lock(&inode->i_lock);
+		netfs_write_remote_i_size(inode, stat->st_size);
 		if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
-			v9fs_i_size_write(inode, stat->st_size);
+			i_size_write(inode, stat->st_size);
 		inode->i_blocks = stat->st_blocks;
+		spin_unlock(&inode->i_lock);
 	} else {
 		if (stat->st_result_mask & P9_STATS_ATIME) {
 			inode_set_atime(inode, stat->st_atime_sec,
@@ -662,13 +664,15 @@ v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode,
 			mode |= inode->i_mode & ~S_IALLUGO;
 			inode->i_mode = mode;
 		}
+		spin_lock(&inode->i_lock);
 		if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE) &&
 		    stat->st_result_mask & P9_STATS_SIZE) {
-			v9inode->netfs.remote_i_size = stat->st_size;
-			v9fs_i_size_write(inode, stat->st_size);
+			netfs_write_remote_i_size(inode, stat->st_size);
+			i_size_write(inode, stat->st_size);
 		}
 		if (stat->st_result_mask & P9_STATS_BLOCKS)
 			inode->i_blocks = stat->st_blocks;
+		spin_unlock(&inode->i_lock);
 	}
 	if (stat->st_result_mask & P9_STATS_GEN)
 		inode->i_generation = stat->st_gen;
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 74d04af51ff4a..650595e1c3f37 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -424,21 +424,35 @@ static void afs_free_request(struct netfs_io_request *rreq)
 	afs_put_wb_key(rreq->netfs_priv2);
 }
 
-static void afs_update_i_size(struct inode *inode, loff_t new_i_size)
+/*
+ * Set the file size and block count, taking ->cb_lock and ->i_lock to maintain
+ * coherency and prevent 64-bit tearing on 32-bit arches.
+ *
+ * Also, estimate the number of 512 bytes blocks used, rounded up to nearest 1K
+ * for consistency with other AFS clients.
+ */
+void afs_set_i_size(struct afs_vnode *vnode, loff_t new_i_size)
 {
-	struct afs_vnode *vnode = AFS_FS_I(inode);
+	struct inode *inode = &vnode->netfs.inode;
 	loff_t i_size;
 
 	write_seqlock(&vnode->cb_lock);
-	i_size = i_size_read(&vnode->netfs.inode);
+	spin_lock(&inode->i_lock);
+	i_size = i_size_read(inode);
 	if (new_i_size > i_size) {
-		i_size_write(&vnode->netfs.inode, new_i_size);
-		inode_set_bytes(&vnode->netfs.inode, new_i_size);
+		i_size_write(inode, new_i_size);
+		inode_set_bytes(inode, round_up(new_i_size, 1024));
 	}
+	spin_unlock(&inode->i_lock);
 	write_sequnlock(&vnode->cb_lock);
 	fscache_update_cookie(afs_vnode_cache(vnode), NULL, &new_i_size);
 }
 
+static void afs_update_i_size(struct inode *inode, loff_t new_i_size)
+{
+	afs_set_i_size(AFS_FS_I(inode), new_i_size);
+}
+
 static void afs_netfs_invalidate_cache(struct netfs_io_request *wreq)
 {
 	struct afs_vnode *vnode = AFS_FS_I(wreq->inode);
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index dde1857fcabb3..df95b39ed308e 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -224,7 +224,8 @@ static int afs_inode_init_from_status(struct afs_operation *op,
 		return afs_protocol_error(NULL, afs_eproto_file_type);
 	}
 
-	afs_set_i_size(vnode, status->size);
+	i_size_write(inode, status->size);
+	inode_set_bytes(inode, status->size);
 	afs_set_netfs_context(vnode);
 
 	vnode->invalid_before	= status->data_version;
@@ -253,7 +254,8 @@ static void afs_apply_status(struct afs_operation *op,
 {
 	struct afs_file_status *status = &vp->scb.status;
 	struct afs_vnode *vnode = vp->vnode;
-	struct inode *inode = &vnode->netfs.inode;
+	struct netfs_inode *ictx = &vnode->netfs;
+	struct inode *inode = &ictx->inode;
 	struct timespec64 t;
 	umode_t mode;
 	bool unexpected_jump = false;
@@ -336,6 +338,8 @@ static void afs_apply_status(struct afs_operation *op,
 	}
 
 	if (data_changed) {
+		unsigned long long zero_point, size = status->size;
+
 		inode_set_iversion_raw(inode, status->data_version);
 
 		/* Only update the size if the data version jumped.  If the
@@ -343,16 +347,25 @@ static void afs_apply_status(struct afs_operation *op,
 		 * idea of what the size should be that's not the same as
 		 * what's on the server.
 		 */
-		vnode->netfs.remote_i_size = status->size;
-		if (change_size || status->size > i_size_read(inode)) {
-			afs_set_i_size(vnode, status->size);
+		spin_lock(&inode->i_lock);
+
+		if (change_size || size > i_size_read(inode)) {
+			/* We can read the sizes directly as we hold i_lock. */
+			zero_point = ictx->_zero_point;
+
 			if (unexpected_jump)
-				vnode->netfs.zero_point = status->size;
+				zero_point = size;
+			netfs_write_sizes(inode, size, size, zero_point);
+			inode_set_bytes(inode, size);
 			inode_set_ctime_to_ts(inode, t);
 			inode_set_atime_to_ts(inode, t);
+		} else {
+			netfs_write_remote_i_size(inode, size);
 		}
+		spin_unlock(&inode->i_lock);
+
 		if (op->ops == &afs_fetch_data_operation)
-			op->fetch.subreq->rreq->i_size = status->size;
+			op->fetch.subreq->rreq->i_size = size;
 	}
 }
 
@@ -709,7 +722,7 @@ int afs_getattr(struct mnt_idmap *idmap, const struct path *path,
 		 * it, but we need to give userspace the server's size.
 		 */
 		if (S_ISDIR(inode->i_mode))
-			stat->size = vnode->netfs.remote_i_size;
+			stat->size = netfs_read_remote_i_size(inode);
 	} while (read_seqretry(&vnode->cb_lock, seq));
 
 	return 0;
@@ -889,7 +902,7 @@ int afs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 		 */
 		if (!(attr->ia_valid & (supported & ~ATTR_SIZE & ~ATTR_MTIME)) &&
 		    attr->ia_size < i_size &&
-		    attr->ia_size > vnode->netfs.remote_i_size) {
+		    attr->ia_size > netfs_read_remote_i_size(inode)) {
 			truncate_setsize(inode, attr->ia_size);
 			netfs_resize_file(&vnode->netfs, size, false);
 			fscache_resize_cookie(afs_vnode_cache(vnode),
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 009064b8d6616..fb0449d024ff2 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -1158,6 +1158,7 @@ extern int afs_open(struct inode *, struct file *);
 extern int afs_release(struct inode *, struct file *);
 void afs_fetch_data_async_rx(struct work_struct *work);
 void afs_fetch_data_immediate_cancel(struct afs_call *call);
+void afs_set_i_size(struct afs_vnode *vnode, loff_t new_i_size);
 
 /*
  * flock.c
@@ -1759,16 +1760,6 @@ static inline void afs_update_dentry_version(struct afs_operation *op,
 			(void *)(unsigned long)dir_vp->scb.status.data_version;
 }
 
-/*
- * Set the file size and block count.  Estimate the number of 512 bytes blocks
- * used, rounded up to nearest 1K for consistency with other AFS clients.
- */
-static inline void afs_set_i_size(struct afs_vnode *vnode, u64 size)
-{
-	i_size_write(&vnode->netfs.inode, size);
-	vnode->netfs.inode.i_blocks = ((size + 1023) >> 10) << 1;
-}
-
 /*
  * Check for a conflicting operation on a directory that we just unlinked from.
  * If someone managed to sneak a link or an unlink in on the file we just
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 93ad86ff33453..e2ef19a73bbfc 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -143,7 +143,7 @@ static void afs_issue_write_worker(struct work_struct *work)
 	afs_begin_vnode_operation(op);
 
 	op->store.write_iter	= &subreq->io_iter;
-	op->store.i_size	= umax(pos + len, vnode->netfs.remote_i_size);
+	op->store.i_size	= umax(pos + len, netfs_read_remote_i_size(&vnode->netfs.inode));
 	op->mtime		= inode_get_mtime(&vnode->netfs.inode);
 
 	afs_wait_for_operation(op);
diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index fee0aebf5a3d6..ebd84a6cc3f09 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -209,7 +209,6 @@ static void netfs_issue_read(struct netfs_io_request *rreq,
 static void netfs_read_to_pagecache(struct netfs_io_request *rreq,
 				    struct readahead_control *ractl)
 {
-	struct netfs_inode *ictx = netfs_inode(rreq->inode);
 	unsigned long long start = rreq->start;
 	ssize_t size = rreq->len;
 	int ret = 0;
@@ -233,7 +232,8 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq,
 		source = netfs_cache_prepare_read(rreq, subreq, rreq->i_size);
 		subreq->source = source;
 		if (source == NETFS_DOWNLOAD_FROM_SERVER) {
-			unsigned long long zp = umin(ictx->zero_point, rreq->i_size);
+			unsigned long long zero_point = netfs_read_zero_point(rreq->inode);
+			unsigned long long zp = umin(zero_point, rreq->i_size);
 			size_t len = subreq->len;
 
 			if (unlikely(rreq->origin == NETFS_READ_SINGLE))
@@ -249,7 +249,7 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq,
 				pr_err("ZERO-LEN READ: R=%08x[%x] l=%zx/%zx s=%llx z=%llx i=%llx",
 				       rreq->debug_id, subreq->debug_index,
 				       subreq->len, size,
-				       subreq->start, ictx->zero_point, rreq->i_size);
+				       subreq->start, zero_point, rreq->i_size);
 				netfs_cancel_read(subreq, ret);
 				break;
 			}
diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index 22a4d61631c9d..c887a30c14d91 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -231,7 +231,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 		 * server would just return a block of zeros or a short read if
 		 * we try to read it.
 		 */
-		if (fpos >= ctx->zero_point) {
+		if (fpos >= netfs_read_zero_point(inode)) {
 			folio_zero_segment(folio, 0, offset);
 			copied = copy_folio_from_iter_atomic(folio, offset, part, iter);
 			if (unlikely(copied == 0))
diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c
index f9ab69de3e298..25f8ceb15fad6 100644
--- a/fs/netfs/direct_write.c
+++ b/fs/netfs/direct_write.c
@@ -376,8 +376,10 @@ ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (ret < 0)
 		goto out;
 	end = iocb->ki_pos + iov_iter_count(from);
-	if (end > ictx->zero_point)
-		ictx->zero_point = end;
+	spin_lock(&inode->i_lock);
+	if (end > ictx->_zero_point)
+		netfs_write_zero_point(inode, end);
+	spin_unlock(&inode->i_lock);
 
 	fscache_invalidate(netfs_i_cookie(ictx), NULL, i_size_read(inode),
 			   FSCACHE_INVAL_DIO_WRITE);
diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c
index 21357907b7eee..bad661ff2bec8 100644
--- a/fs/netfs/misc.c
+++ b/fs/netfs/misc.c
@@ -211,18 +211,25 @@ EXPORT_SYMBOL(netfs_clear_inode_writeback);
 void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length)
 {
 	struct netfs_folio *finfo;
-	struct netfs_inode *ctx = netfs_inode(folio_inode(folio));
+	struct inode *inode = folio_inode(folio);
+	struct netfs_inode *ctx = netfs_inode(inode);
 	size_t flen = folio_size(folio);
 
 	_enter("{%lx},%zx,%zx", folio->index, offset, length);
 
 	if (offset == 0 && length == flen) {
-		unsigned long long i_size = i_size_read(&ctx->inode);
+		unsigned long long i_size, remote_i_size, zero_point;
 		unsigned long long fpos = folio_pos(folio), end;
 
+		netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point);
 		end = umin(fpos + flen, i_size);
-		if (fpos < i_size && end > ctx->zero_point)
-			ctx->zero_point = end;
+		if (fpos < i_size && end > zero_point) {
+			spin_lock(&inode->i_lock);
+			end = umin(fpos + flen, inode->i_size);
+			if (fpos < i_size && end > ctx->_zero_point)
+				netfs_write_zero_point(inode, end);
+			spin_unlock(&inode->i_lock);
+		}
 	}
 
 	folio_wait_private_2(folio); /* [DEPRECATED] */
@@ -292,15 +299,22 @@ EXPORT_SYMBOL(netfs_invalidate_folio);
  */
 bool netfs_release_folio(struct folio *folio, gfp_t gfp)
 {
-	struct netfs_inode *ctx = netfs_inode(folio_inode(folio));
-	unsigned long long end;
+	struct inode *inode = folio_inode(folio);
+	struct netfs_inode *ctx = netfs_inode(inode);
+	unsigned long long i_size, remote_i_size, zero_point, end;
 
 	if (folio_test_dirty(folio))
 		return false;
 
-	end = umin(folio_next_pos(folio), i_size_read(&ctx->inode));
-	if (end > ctx->zero_point)
-		ctx->zero_point = end;
+	netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point);
+	end = umin(folio_next_pos(folio), i_size);
+	if (end > zero_point) {
+		spin_lock(&inode->i_lock);
+		end = umin(folio_next_pos(folio), inode->i_size);
+		if (end > ctx->_zero_point)
+			netfs_write_zero_point(inode, end);
+		spin_unlock(&inode->i_lock);
+	}
 
 	if (folio_test_private(folio))
 		return false;
diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c
index 7fbf50907a7fc..24fc2bb2f8a47 100644
--- a/fs/netfs/write_collect.c
+++ b/fs/netfs/write_collect.c
@@ -57,7 +57,8 @@ static void netfs_dump_request(const struct netfs_io_request *rreq)
 int netfs_folio_written_back(struct folio *folio)
 {
 	enum netfs_folio_trace why = netfs_folio_trace_clear;
-	struct netfs_inode *ictx = netfs_inode(folio->mapping->host);
+	struct inode *inode = folio_inode(folio);
+	struct netfs_inode *ictx = netfs_inode(inode);
 	struct netfs_folio *finfo;
 	struct netfs_group *group = NULL;
 	int gcount = 0;
@@ -69,8 +70,10 @@ int netfs_folio_written_back(struct folio *folio)
 		unsigned long long fend;
 
 		fend = folio_pos(folio) + finfo->dirty_offset + finfo->dirty_len;
-		if (fend > ictx->zero_point)
-			ictx->zero_point = fend;
+		spin_lock(&ictx->inode.i_lock);
+		if (fend > ictx->_zero_point)
+			netfs_write_zero_point(inode, fend);
+		spin_unlock(&ictx->inode.i_lock);
 
 		folio_detach_private(folio);
 		group = finfo->netfs_group;
diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index 97931e1ae3b2b..db6062dcbb3ec 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -470,7 +470,8 @@ cifs_alloc_inode(struct super_block *sb)
 	spin_lock_init(&cifs_inode->writers_lock);
 	cifs_inode->writers = 0;
 	cifs_inode->netfs.inode.i_blkbits = 14;  /* 2**14 = CIFS_MAX_MSGSIZE */
-	cifs_inode->netfs.remote_i_size = 0;
+	cifs_inode->netfs._remote_i_size = 0;
+	cifs_inode->netfs._zero_point = 0;
 	cifs_inode->uniqueid = 0;
 	cifs_inode->createtime = 0;
 	cifs_inode->epoch = 0;
@@ -1338,7 +1339,8 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
 	struct cifsFileInfo *smb_file_src = src_file->private_data;
 	struct cifsFileInfo *smb_file_target = dst_file->private_data;
 	struct cifs_tcon *target_tcon, *src_tcon;
-	unsigned long long destend, fstart, fend, old_size, new_size;
+	unsigned long long i_size, old_size, new_size, zero_point;
+	unsigned long long destend, fstart, fend;
 	unsigned int xid;
 	int rc;
 
@@ -1382,7 +1384,7 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
 	 * Advance the EOF marker after the flush above to the end of the range
 	 * if it's short of that.
 	 */
-	if (src_cifsi->netfs.remote_i_size < off + len) {
+	if (netfs_read_remote_i_size(src_inode) < off + len) {
 		rc = cifs_precopy_set_eof(src_inode, src_cifsi, src_tcon, xid, off + len);
 		if (rc < 0)
 			goto unlock;
@@ -1403,16 +1405,18 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
 	rc = cifs_flush_folio(target_inode, destend, &fstart, &fend, false);
 	if (rc)
 		goto unlock;
-	if (fend > target_cifsi->netfs.zero_point)
-		target_cifsi->netfs.zero_point = fend + 1;
-	old_size = target_cifsi->netfs.remote_i_size;
+
+	spin_lock(&target_inode->i_lock);
+	if (fend > zero_point)
+		netfs_write_zero_point(target_inode, fend + 1);
+	i_size = target_inode->i_size;
+	spin_unlock(&target_inode->i_lock);
 
 	/* Discard all the folios that overlap the destination region. */
 	cifs_dbg(FYI, "about to discard pages %llx-%llx\n", fstart, fend);
 	truncate_inode_pages_range(&target_inode->i_data, fstart, fend);
 
-	fscache_invalidate(cifs_inode_cookie(target_inode), NULL,
-			   i_size_read(target_inode), 0);
+	fscache_invalidate(cifs_inode_cookie(target_inode), NULL, i_size, 0);
 
 	rc = -EOPNOTSUPP;
 	if (target_tcon->ses->server->ops->duplicate_extents) {
@@ -1437,8 +1441,12 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
 					rc = -EINVAL;
 			}
 		}
-		if (rc == 0 && new_size > target_cifsi->netfs.zero_point)
-			target_cifsi->netfs.zero_point = new_size;
+		if (rc == 0) {
+			spin_lock(&target_inode->i_lock);
+			if (new_size > target_cifsi->netfs._zero_point)
+				netfs_write_zero_point(target_inode, new_size);
+			spin_unlock(&target_inode->i_lock);
+		}
 	}
 
 	/* force revalidate of size and timestamps of target file now
@@ -1509,7 +1517,7 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
 	 * Advance the EOF marker after the flush above to the end of the range
 	 * if it's short of that.
 	 */
-	if (src_cifsi->netfs.remote_i_size < off + len) {
+	if (netfs_read_remote_i_size(src_inode) < off + len) {
 		rc = cifs_precopy_set_eof(src_inode, src_cifsi, src_tcon, xid, off + len);
 		if (rc < 0)
 			goto unlock;
@@ -1537,8 +1545,12 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
 			fscache_resize_cookie(cifs_inode_cookie(target_inode),
 					      i_size_read(target_inode));
 		}
-		if (rc > 0 && destoff + rc > target_cifsi->netfs.zero_point)
-			target_cifsi->netfs.zero_point = destoff + rc;
+		if (rc > 0) {
+			spin_lock(&target_inode->i_lock);
+			if (destoff + rc > target_cifsi->netfs._zero_point)
+				netfs_write_zero_point(target_inode, destoff + rc);
+			spin_unlock(&target_inode->i_lock);
+		}
 	}
 
 	file_accessed(src_file);
diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c
index 3990a90122640..9e27bfa7376b1 100644
--- a/fs/smb/client/cifssmb.c
+++ b/fs/smb/client/cifssmb.c
@@ -1465,6 +1465,7 @@ cifs_readv_callback(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 	struct cifs_io_subrequest *rdata = mid->callback_data;
 	struct netfs_inode *ictx = netfs_inode(rdata->rreq->inode);
 	struct cifs_tcon *tcon = tlink_tcon(rdata->req->cfile->tlink);
+	struct inode *inode = &ictx->inode;
 	struct smb_rqst rqst = { .rq_iov = rdata->iov,
 				 .rq_nvec = 1,
 				 .rq_iter = rdata->subreq.io_iter };
@@ -1538,7 +1539,7 @@ cifs_readv_callback(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 	} else {
 		size_t trans = rdata->subreq.transferred + rdata->got_bytes;
 		if (trans < rdata->subreq.len &&
-		    rdata->subreq.start + trans >= ictx->remote_i_size) {
+		    rdata->subreq.start + trans >= netfs_read_remote_i_size(inode)) {
 			rdata->result = 0;
 			__set_bit(NETFS_SREQ_HIT_EOF, &rdata->subreq.flags);
 		} else if (rdata->got_bytes > 0) {
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index a69e05f86d7e2..ad624c01193eb 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -2491,18 +2491,23 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *flock)
 void cifs_write_subrequest_terminated(struct cifs_io_subrequest *wdata, ssize_t result)
 {
 	struct netfs_io_request *wreq = wdata->rreq;
-	struct netfs_inode *ictx = netfs_inode(wreq->inode);
+	struct inode *inode = wreq->inode;
+	struct netfs_inode *ictx = netfs_inode(inode);
 	loff_t wrend;
 
 	if (result > 0) {
+		spin_lock(&inode->i_lock);
+
 		wrend = wdata->subreq.start + wdata->subreq.transferred + result;
 
-		if (wrend > ictx->zero_point &&
+		if (wrend > ictx->_zero_point &&
 		    (wdata->rreq->origin == NETFS_UNBUFFERED_WRITE ||
 		     wdata->rreq->origin == NETFS_DIO_WRITE))
-			ictx->zero_point = wrend;
-		if (wrend > ictx->remote_i_size)
+			netfs_write_zero_point(inode, wrend);
+		if (wrend > ictx->_remote_i_size)
 			netfs_resize_file(ictx, wrend, true);
+
+		spin_unlock(&inode->i_lock);
 	}
 
 	netfs_write_subrequest_terminated(&wdata->subreq, result);
diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index 888f9e35f14b8..5b1beba77c0ec 100644
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -119,7 +119,7 @@ cifs_revalidate_cache(struct inode *inode, struct cifs_fattr *fattr)
 	fattr->cf_mtime = timestamp_truncate(fattr->cf_mtime, inode);
 	mtime = inode_get_mtime(inode);
 	if (timespec64_equal(&mtime, &fattr->cf_mtime) &&
-	    cifs_i->netfs.remote_i_size == fattr->cf_eof) {
+	    netfs_read_remote_i_size(inode) == fattr->cf_eof) {
 		cifs_dbg(FYI, "%s: inode %llu is unchanged\n",
 			 __func__, cifs_i->uniqueid);
 		return;
@@ -173,12 +173,12 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr,
 		CIFS_I(inode)->time = 0; /* force reval */
 		return -ESTALE;
 	}
-	if (inode_state_read_once(inode) & I_NEW)
-		CIFS_I(inode)->netfs.zero_point = fattr->cf_eof;
-
 	cifs_revalidate_cache(inode, fattr);
 
 	spin_lock(&inode->i_lock);
+	if (inode_state_read_once(inode) & I_NEW)
+		netfs_write_zero_point(inode, fattr->cf_eof);
+
 	fattr->cf_mtime = timestamp_truncate(fattr->cf_mtime, inode);
 	fattr->cf_atime = timestamp_truncate(fattr->cf_atime, inode);
 	fattr->cf_ctime = timestamp_truncate(fattr->cf_ctime, inode);
@@ -212,7 +212,7 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr,
 	else
 		clear_bit(CIFS_INO_DELETE_PENDING, &cifs_i->flags);
 
-	cifs_i->netfs.remote_i_size = fattr->cf_eof;
+	netfs_write_remote_i_size(inode, fattr->cf_eof);
 	/*
 	 * Can't safely change the file size here if the client is writing to
 	 * it due to potential races.
@@ -2771,7 +2771,9 @@ cifs_revalidate_mapping(struct inode *inode)
 		if (cifs_sb_flags(cifs_sb) & CIFS_MOUNT_RW_CACHE)
 			goto skip_invalidate;
 
-		cifs_inode->netfs.zero_point = cifs_inode->netfs.remote_i_size;
+		spin_lock(&inode->i_lock);
+		netfs_write_zero_point(inode, netfs_inode(inode)->_remote_i_size);
+		spin_unlock(&inode->i_lock);
 		rc = filemap_invalidate_inode(inode, true, 0, LLONG_MAX);
 		if (rc) {
 			cifs_dbg(VFS, "%s: invalidate inode %p failed with rc %d\n",
diff --git a/fs/smb/client/readdir.c b/fs/smb/client/readdir.c
index be22bbc4a65a0..e860fa08b5e30 100644
--- a/fs/smb/client/readdir.c
+++ b/fs/smb/client/readdir.c
@@ -143,7 +143,8 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
 						fattr->cf_rdev = inode->i_rdev;
 						fattr->cf_uid = inode->i_uid;
 						fattr->cf_gid = inode->i_gid;
-						fattr->cf_eof = CIFS_I(inode)->netfs.remote_i_size;
+						fattr->cf_eof =
+							netfs_read_remote_i_size(inode);
 						fattr->cf_symlink_target = NULL;
 					} else {
 						CIFS_I(inode)->time = 0;
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 00735607ce953..a07d72cd16dc1 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -3402,8 +3402,7 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
 	struct inode *inode = file_inode(file);
 	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 	struct cifsFileInfo *cfile = file->private_data;
-	struct netfs_inode *ictx = netfs_inode(inode);
-	unsigned long long i_size, new_size, remote_size;
+	unsigned long long i_size, new_size, remote_i_size, zero_point;
 	long rc;
 	unsigned int xid;
 
@@ -3414,9 +3413,8 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
 
 	filemap_invalidate_lock(inode->i_mapping);
 
-	i_size = i_size_read(inode);
-	remote_size = ictx->remote_i_size;
-	if (offset + len >= remote_size && offset < i_size) {
+	netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point);
+	if (offset + len >= remote_i_size && offset < i_size) {
 		unsigned long long top = umin(offset + len, i_size);
 
 		rc = filemap_write_and_wait_range(inode->i_mapping, offset, top - 1);
@@ -3449,9 +3447,11 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
 				  cfile->fid.volatile_fid, cfile->pid, new_size);
 		if (rc >= 0) {
 			truncate_setsize(inode, new_size);
+			spin_lock(&inode->i_lock);
 			netfs_resize_file(&cifsi->netfs, new_size, true);
-			if (offset < cifsi->netfs.zero_point)
-				cifsi->netfs.zero_point = offset;
+			if (offset < cifsi->netfs._zero_point)
+				netfs_write_zero_point(inode, offset);
+			spin_unlock(&inode->i_lock);
 			fscache_resize_cookie(cifs_inode_cookie(inode), new_size);
 		}
 	}
@@ -3474,7 +3474,7 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
 	struct inode *inode = file_inode(file);
 	struct cifsFileInfo *cfile = file->private_data;
 	struct file_zero_data_information fsctl_buf;
-	unsigned long long end = offset + len, i_size, remote_i_size;
+	unsigned long long end = offset + len, i_size, remote_i_size, zero_point;
 	long rc;
 	unsigned int xid;
 	__u8 set_sparse = 1;
@@ -3516,14 +3516,17 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
 	 * that we locally hole-punch the tail of the dirty data, the proposed
 	 * EOF update will end up in the wrong place.
 	 */
-	i_size = i_size_read(inode);
-	remote_i_size = netfs_inode(inode)->remote_i_size;
+	netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point);
+
 	if (end > remote_i_size && i_size > remote_i_size) {
 		unsigned long long extend_to = umin(end, i_size);
 		rc = SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
 				  cfile->fid.volatile_fid, cfile->pid, extend_to);
-		if (rc >= 0)
-			netfs_inode(inode)->remote_i_size = extend_to;
+		if (rc >= 0) {
+			spin_lock(&inode->i_lock);
+			netfs_write_remote_i_size(inode, extend_to);
+			spin_unlock(&inode->i_lock);
+		}
 	}
 
 unlock:
@@ -3787,7 +3790,6 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon,
 	struct inode *inode = file_inode(file);
 	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 	struct cifsFileInfo *cfile = file->private_data;
-	struct netfs_inode *ictx = &cifsi->netfs;
 	loff_t old_eof, new_eof;
 
 	xid = get_xid();
@@ -3805,7 +3807,9 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon,
 		goto out_2;
 
 	truncate_pagecache_range(inode, off, old_eof);
-	ictx->zero_point = old_eof;
+	spin_lock(&inode->i_lock);
+	netfs_write_zero_point(inode, old_eof);
+	spin_unlock(&inode->i_lock);
 	netfs_wait_for_outstanding_io(inode);
 
 	rc = smb2_copychunk_range(xid, cfile, cfile, off + len,
@@ -3822,8 +3826,10 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon,
 	rc = 0;
 
 	truncate_setsize(inode, new_eof);
+	spin_lock(&inode->i_lock);
 	netfs_resize_file(&cifsi->netfs, new_eof, true);
-	ictx->zero_point = new_eof;
+	netfs_write_zero_point(inode, new_eof);
+	spin_unlock(&inode->i_lock);
 	fscache_resize_cookie(cifs_inode_cookie(inode), new_eof);
 out_2:
 	filemap_invalidate_unlock(inode->i_mapping);
@@ -3866,13 +3872,17 @@ static long smb3_insert_range(struct file *file, struct cifs_tcon *tcon,
 		goto out_2;
 
 	truncate_setsize(inode, new_eof);
+	spin_lock(&inode->i_lock);
 	netfs_resize_file(&cifsi->netfs, i_size_read(inode), true);
+	spin_unlock(&inode->i_lock);
 	fscache_resize_cookie(cifs_inode_cookie(inode), i_size_read(inode));
 
 	rc = smb2_copychunk_range(xid, cfile, cfile, off, count, off + len);
 	if (rc < 0)
 		goto out_2;
-	cifsi->netfs.zero_point = new_eof;
+	spin_lock(&inode->i_lock);
+	netfs_write_zero_point(inode, new_eof);
+	spin_unlock(&inode->i_lock);
 
 	rc = smb3_zero_data(file, tcon, off, len, xid);
 	if (rc < 0)
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 5188218c25be4..967047894a1e6 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -4596,6 +4596,7 @@ smb2_readv_callback(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 	struct netfs_inode *ictx = netfs_inode(rdata->rreq->inode);
 	struct cifs_tcon *tcon = tlink_tcon(rdata->req->cfile->tlink);
 	struct smb2_hdr *shdr = (struct smb2_hdr *)rdata->iov[0].iov_base;
+	struct inode *inode = &ictx->inode;
 	struct cifs_credits credits = {
 		.value = 0,
 		.instance = 0,
@@ -4709,7 +4710,7 @@ smb2_readv_callback(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 	} else {
 		size_t trans = rdata->subreq.transferred + rdata->got_bytes;
 		if (trans < rdata->subreq.len &&
-		    rdata->subreq.start + trans >= ictx->remote_i_size) {
+		    rdata->subreq.start + trans >= netfs_read_remote_i_size(inode)) {
 			__set_bit(NETFS_SREQ_HIT_EOF, &rdata->subreq.flags);
 			rdata->result = 0;
 		}
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index ba17ac5bf356a..4fd1d796ad73b 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -62,8 +62,8 @@ struct netfs_inode {
 	struct fscache_cookie	*cache;
 #endif
 	struct mutex		wb_lock;	/* Writeback serialisation */
-	loff_t			remote_i_size;	/* Size of the remote file */
-	loff_t			zero_point;	/* Size after which we assume there's no data
+	loff_t			_remote_i_size;	/* Size of the remote file */
+	loff_t			_zero_point;	/* Size after which we assume there's no data
 						 * on the server */
 	atomic_t		io_count;	/* Number of outstanding reqs */
 	unsigned long		flags;
@@ -474,6 +474,254 @@ static inline struct netfs_inode *netfs_inode(struct inode *inode)
 	return container_of(inode, struct netfs_inode, inode);
 }
 
+/**
+ * netfs_read_remote_i_size - Read remote_i_size safely
+ * @inode: The inode to access
+ *
+ * Read remote_i_size safely without the potential for tearing on 32-bit
+ * arches.
+ *
+ * NOTE: in a 32bit arch with a preemptable kernel and an UP compile the
+ * i_size_read/write must be atomic with respect to the local cpu (unlike with
+ * preempt disabled), but they don't need to be atomic with respect to other
+ * cpus like in true SMP (so they need either to either locally disable irq
+ * around the read or for example on x86 they can be still implemented as a
+ * cmpxchg8b without the need of the lock prefix).  For SMP compiles and 64bit
+ * archs it makes no difference if preempt is enabled or not.
+ */
+static inline unsigned long long netfs_read_remote_i_size(const struct inode *inode)
+{
+	const struct netfs_inode *ictx = container_of(inode, struct netfs_inode, inode);
+	unsigned long long remote_i_size;
+
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+	unsigned int seq;
+
+	do {
+		seq = read_seqcount_begin(&inode->i_size_seqcount);
+		remote_i_size = ictx->_remote_i_size;
+	} while (read_seqcount_retry(&inode->i_size_seqcount, seq));
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
+	preempt_disable();
+	remote_i_size = ictx->_remote_i_size;
+	preempt_enable();
+#else
+	/* Pairs with smp_store_release() in netfs_write_remote_i_size() */
+	remote_i_size = smp_load_acquire(&ictx->_remote_i_size);
+#endif
+	return remote_i_size;
+}
+
+/*
+ * netfs_write_remote_i_size - Set remote_i_size safely
+ * @inode: The inode to access
+ * @remote_i_size: The new value for the size of the file on the server
+ *
+ * Set remote_i_size safely without the potential for tearing on 32-bit arches.
+ *
+ * Context: The caller must hold inode->i_lock.
+ *
+ * NOTE: unlike netfs_read_remote_i_size(), netfs_write_remote_i_size() does
+ * need locking around it (normally i_rwsem), otherwise on 32bit/SMP an update
+ * of i_size_seqcount can be lost, resulting in subsequent i_size_read() calls
+ * spinning forever.
+ */
+static inline void netfs_write_remote_i_size(struct inode *inode,
+					     unsigned long long remote_i_size)
+{
+	struct netfs_inode *ictx = netfs_inode(inode);
+
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+	write_seqcount_begin(&inode->i_size_seqcount);
+	ictx->_remote_i_size = remote_i_size;
+	write_seqcount_end(&inode->i_size_seqcount);
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
+	preempt_disable();
+	ictx->_remote_i_size = remote_i_size;
+	preempt_enable();
+#else
+	/*
+	 * Pairs with smp_load_acquire() in netfs_read_remote_i_size() to
+	 * ensure changes related to inode size (such as page contents) are
+	 * visible before we see the changed inode size.
+	 */
+	smp_store_release(&ictx->_remote_i_size, remote_i_size);
+#endif
+}
+
+/**
+ * netfs_read_zero_point - Read zero_point safely
+ * @inode: The inode to access
+ *
+ * Read zero_point safely without the potential for tearing on 32-bit
+ * arches.
+ *
+ * NOTE: in a 32bit arch with a preemptable kernel and an UP compile the
+ * i_size_read/write must be atomic with respect to the local cpu (unlike with
+ * preempt disabled), but they don't need to be atomic with respect to other
+ * cpus like in true SMP (so they need either to either locally disable irq
+ * around the read or for example on x86 they can be still implemented as a
+ * cmpxchg8b without the need of the lock prefix).  For SMP compiles and 64bit
+ * archs it makes no difference if preempt is enabled or not.
+ */
+static inline unsigned long long netfs_read_zero_point(const struct inode *inode)
+{
+	struct netfs_inode *ictx = container_of(inode, struct netfs_inode, inode);
+	unsigned long long zero_point;
+
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+	unsigned int seq;
+
+	do {
+		seq = read_seqcount_begin(&inode->i_size_seqcount);
+		zero_point = ictx->_zero_point;
+	} while (read_seqcount_retry(&inode->i_size_seqcount, seq));
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
+	preempt_disable();
+	zero_point = ictx->_zero_point;
+	preempt_enable();
+#else
+	/* Pairs with smp_store_release() in netfs_write_zero_point() */
+	zero_point = smp_load_acquire(&ictx->_zero_point);
+#endif
+	return zero_point;
+}
+
+/*
+ * netfs_write_zero_point - Set zero_point safely
+ * @inode: The inode to access
+ * @zero_point: The new value for the point beyond which the server has no data
+ *
+ * Set zero_point safely without the potential for tearing on 32-bit arches.
+ *
+ * Context: The caller must hold inode->i_lock.
+ *
+ * NOTE: unlike netfs_read_zero_point(), netfs_write_zero_point() does need
+ * locking around it (normally i_rwsem), otherwise on 32bit/SMP an update of
+ * i_size_seqcount can be lost, resulting in subsequent read calls spinning
+ * forever.
+ */
+static inline void netfs_write_zero_point(struct inode *inode,
+					  unsigned long long zero_point)
+{
+	struct netfs_inode *ictx = netfs_inode(inode);
+
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+	write_seqcount_begin(&inode->i_size_seqcount);
+	ictx->_zero_point = zero_point;
+	write_seqcount_end(&inode->i_size_seqcount);
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
+	preempt_disable();
+	ictx->_zero_point = zero_point;
+	preempt_enable();
+#else
+	/*
+	 * Pairs with smp_load_acquire() in netfs_read_zero_point() to
+	 * ensure changes related to inode size (such as page contents) are
+	 * visible before we see the changed inode size.
+	 */
+	smp_store_release(&ictx->_zero_point, zero_point);
+#endif
+}
+
+/**
+ * netfs_read_sizes - Read remote_i_size and zero_point safely
+ * @inode: The inode to access
+ * @i_size: Where to return the local file size.
+ * @remote_i_size: Where to return the size of the file on the server
+ * @zero_point: Where to return the the point beyond which the server has no data
+ *
+ * Read remote_i_size and zero_point safely without the potential for tearing
+ * on 32-bit arches.
+ *
+ * NOTE: in a 32bit arch with a preemptable kernel and an UP compile the
+ * i_size_read/write must be atomic with respect to the local cpu (unlike with
+ * preempt disabled), but they don't need to be atomic with respect to other
+ * cpus like in true SMP (so they need either to either locally disable irq
+ * around the read or for example on x86 they can be still implemented as a
+ * cmpxchg8b without the need of the lock prefix).  For SMP compiles and 64bit
+ * archs it makes no difference if preempt is enabled or not.
+ */
+static inline void netfs_read_sizes(const struct inode *inode,
+				    unsigned long long *i_size,
+				    unsigned long long *remote_i_size,
+				    unsigned long long *zero_point)
+{
+	const struct netfs_inode *ictx = container_of(inode, struct netfs_inode, inode);
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+	unsigned int seq;
+
+	do {
+		seq = read_seqcount_begin(&inode->i_size_seqcount);
+		*i_size = inode->i_size;
+		*remote_i_size = ictx->_remote_i_size;
+		*zero_point = ictx->_zero_point;
+	} while (read_seqcount_retry(&inode->i_size_seqcount, seq));
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
+	preempt_disable();
+	*i_size = inode->i_size;
+	*remote_i_size = ictx->_remote_i_size;
+	*zero_point = ictx->_zero_point;
+	preempt_enable();
+#else
+	/* Pairs with smp_store_release() in i_size_write() */
+	*i_size = smp_load_acquire(&inode->i_size);
+	/* Pairs with smp_store_release() in netfs_write_remote_i_size() */
+	*remote_i_size = smp_load_acquire(&ictx->_remote_i_size);
+	/* Pairs with smp_store_release() in netfs_write_zero_point() */
+	*zero_point = smp_load_acquire(&ictx->_zero_point);
+#endif
+}
+
+/*
+ * netfs_write_sizes - Set i_size, remote_i_size and zero_point safely
+ * @inode: The inode to access
+ * @i_size: The new value for the local size of the file
+ * @remote_i_size: The new value for the size of the file on the server
+ * @zero_point: The new value for the point beyond which the server has no data
+ *
+ * Set both remote_i_size and zero_point safely without the potential for
+ * tearing on 32-bit arches.
+ *
+ * Context: The caller must hold inode->i_lock.
+ *
+ * NOTE: unlike netfs_read_zero_point(), netfs_write_zero_point() does need
+ * locking around it (normally i_rwsem), otherwise on 32bit/SMP an update of
+ * i_size_seqcount can be lost, resulting in subsequent read calls spinning
+ * forever.
+ */
+static inline void netfs_write_sizes(struct inode *inode,
+				     unsigned long long i_size,
+				     unsigned long long remote_i_size,
+				     unsigned long long zero_point)
+{
+	struct netfs_inode *ictx = netfs_inode(inode);
+
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+	write_seqcount_begin(&inode->i_size_seqcount);
+	inode->i_size = i_size;
+	ictx->_remote_i_size = remote_i_size;
+	ictx->_zero_point = zero_point;
+	write_seqcount_end(&inode->i_size_seqcount);
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
+	preempt_disable();
+	inode->i_size = i_size;
+	ictx->_remote_i_size = remote_i_size;
+	ictx->_zero_point = zero_point;
+	preempt_enable();
+#else
+	/*
+	 * Pairs with smp_load_acquire() in i_size_read(),
+	 * netfs_read_remote_i_size() and netfs_read_zero_point() to ensure
+	 * changes related to inode size (such as page contents) are visible
+	 * before we see the changed inode size.
+	 */
+	smp_store_release(&inode->i_size, i_size);
+	smp_store_release(&ictx->_remote_i_size, remote_i_size);
+	smp_store_release(&ictx->_zero_point, zero_point);
+#endif
+}
+
 /**
  * netfs_inode_init - Initialise a netfslib inode context
  * @ctx: The netfs inode to initialise
@@ -488,8 +736,8 @@ static inline void netfs_inode_init(struct netfs_inode *ctx,
 				    bool use_zero_point)
 {
 	ctx->ops = ops;
-	ctx->remote_i_size = i_size_read(&ctx->inode);
-	ctx->zero_point = LLONG_MAX;
+	ctx->_remote_i_size = i_size_read(&ctx->inode);
+	ctx->_zero_point = LLONG_MAX;
 	ctx->flags = 0;
 	atomic_set(&ctx->io_count, 0);
 #if IS_ENABLED(CONFIG_FSCACHE)
@@ -498,7 +746,7 @@ static inline void netfs_inode_init(struct netfs_inode *ctx,
 	mutex_init(&ctx->wb_lock);
 	/* ->releasepage() drives zero_point */
 	if (use_zero_point) {
-		ctx->zero_point = ctx->remote_i_size;
+		ctx->_zero_point = ctx->_remote_i_size;
 		mapping_set_release_always(ctx->inode.i_mapping);
 	}
 }
@@ -511,13 +759,40 @@ static inline void netfs_inode_init(struct netfs_inode *ctx,
  *
  * Inform the netfs lib that a file got resized so that it can adjust its state.
  */
-static inline void netfs_resize_file(struct netfs_inode *ctx, loff_t new_i_size,
+static inline void netfs_resize_file(struct netfs_inode *ictx,
+				     unsigned long long new_i_size,
 				     bool changed_on_server)
 {
+#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+	struct inode *inode = &ictx->inode;
+
+	preempt_disable();
+	write_seqcount_begin(&inode->i_size_seqcount);
+	if (changed_on_server)
+		ictx->_remote_i_size = new_i_size;
+	if (new_i_size < ictx->_zero_point)
+		ictx->_zero_point = new_i_size;
+	write_seqcount_end(&inode->i_size_seqcount);
+	preempt_enable();
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
+	preempt_disable();
 	if (changed_on_server)
-		ctx->remote_i_size = new_i_size;
-	if (new_i_size < ctx->zero_point)
-		ctx->zero_point = new_i_size;
+		ictx->_remote_i_size = new_i_size;
+	if (new_i_size < ictx->_zero_point)
+		ictx->_zero_point = new_i_size;
+	preempt_enable();
+#else
+	/*
+	 * Pairs with smp_load_acquire() in netfs_read_remote_i_size and
+	 * netfs_read_zero_point() to ensure changes related to inode size
+	 * (such as page contents) are visible before we see the changed inode
+	 * size.
+	 */
+	if (changed_on_server)
+		smp_store_release(&ictx->_remote_i_size, new_i_size);
+	if (new_i_size < ictx->_zero_point)
+		smp_store_release(&ictx->_zero_point, new_i_size);
+#endif
 }
 
 /**
-- 
2.53.0

[PATCH 7.0 255/461] netfs: Fix zeropoint update where i_size > remote_i_size

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 4543a4d737944134a1394afe797622546fbcc98a ]

Fix the update of the zero point[*] by netfs_release_folio() when there is
uncommitted data in the pagecache beyond the folio being released but the
on-server EOF is in this folio (ie. i_size > remote_i_size).  The update
needs to limit zero_point to remote_i_size, not i_size as i_size is a local
phenomenon reflecting updates made locally to the pagecache, not stuff
written to the server.  remote_i_size tracks the server's i_size.

[*] The zero point is the file position from which we can assume that the
    server will just return zeros, so we can avoid generating reads.

Note that netfs_invalidate_folio() probably doesn't need fixing as
zero_point should be updated by setattr after truncation or fallocate.

Found with:

    fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \
        /xfstest.test/junk --replay-ops=junk.fsxops

using the following as junk.fsxops:

    truncate 0x0 0x1bbae 0x82864
    write 0x3ef2e 0xf9c8 0x1bbae
    write 0x67e05 0xcb5a 0x4e8f6
    mapread 0x57781 0x85b6 0x7495f
    copy_range 0x5d3d 0x10329 0x54fac 0x7495f
    write 0x64710 0x1c2b 0x7495f
    mapread 0x64000 0x1000 0x7495f

on cifs with the default cache option.

It shows read-gaps on folio 0x64 failing with a short read (ie. it hits
EOF) if the FMODE_READ check is commented out in netfs_perform_write():

                if (//(file->f_mode & FMODE_READ) ||
                    netfs_is_cache_enabled(ctx)) {

and no fscache.  This was initially found with the generic/522 xfstest.

Fixes: cce6bfa6ca0e ("netfs: Fix trimming of streaming-write folios in netfs_inval_folio()")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-7-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/misc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c
index bad661ff2bec8..723571ca1b885 100644
--- a/fs/netfs/misc.c
+++ b/fs/netfs/misc.c
@@ -307,10 +307,10 @@ bool netfs_release_folio(struct folio *folio, gfp_t gfp)
 		return false;
 
 	netfs_read_sizes(inode, &i_size, &remote_i_size, &zero_point);
-	end = umin(folio_next_pos(folio), i_size);
+	end = folio_next_pos(folio);
 	if (end > zero_point) {
 		spin_lock(&inode->i_lock);
-		end = umin(folio_next_pos(folio), inode->i_size);
+		end = umin(end, ctx->_remote_i_size);
 		if (end > ctx->_zero_point)
 			netfs_write_zero_point(inode, end);
 		spin_unlock(&inode->i_lock);
-- 
2.53.0

[PATCH 7.0 256/461] netfs: fix VM_BUG_ON_FOLIO() issue in netfs_write_begin() call

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>

[ Upstream commit dc7832d05deb4d632e8035e3299e31a3528fa0d0 ]

The multiple runs of generic/013 test-case is capable
to reproduce a kernel BUG at mm/filemap.c:1504 with
probability of 30%.

while true; do
  sudo ./check generic/013
done

[ 9849.452376] page: refcount:3 mapcount:0 mapping:00000000e58ff252 index:0x10781 pfn:0x1c322
[ 9849.452412] memcg:ffff8881a1915800
[ 9849.452417] aops:ceph_aops ino:1000058db9e dentry name(?):"f9XXXXXX"
[ 9849.452432] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
[ 9849.452441] raw: 0017ffffc0000000 0000000000000000 dead000000000122 ffff88816110d248
[ 9849.452445] raw: 0000000000010781 0000000000000000 00000003ffffffff ffff8881a1915800
[ 9849.452447] page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio))
[ 9849.452474] ------------[ cut here ]------------
[ 9849.452476] kernel BUG at mm/filemap.c:1504!
[ 9849.478635] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
[ 9849.481772] CPU: 2 UID: 0 PID: 84223 Comm: fsstress Not tainted 7.0.0-rc1+ #18 PREEMPT(full)
[ 9849.482881] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-9.fc43 06/1
0/2025
[ 9849.484539] RIP: 0010:folio_unlock+0x85/0xa0
[ 9849.485076] Code: 89 df 31 f6 e8 1c f3 ff ff 48 8b 5d f8 c9 31 c0 31 d2 31 f6 31 ff c3 cc
cc cc cc 48 c7 c6 80 6c d9 a7 48 89 df e8 4b b3 10 00 <0f> 0b 48 89 df e8 21 e6 2c 00 eb 9d 0f 1f 40 00 66 66 2e 0f 1f 84
[ 9849.493818] RSP: 0018:ffff8881bb8076b0 EFLAGS: 00010246
[ 9849.495740] RAX: 0000000000000000 RBX: ffffea00070c8980 RCX: 0000000000000000
[ 9849.498678] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 9849.500559] RBP: ffff8881bb8076b8 R08: 0000000000000000 R09: 0000000000000000
[ 9849.501097] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000010782000
[ 9849.502108] R13: ffff8881935de738 R14: ffff88816110d010 R15: 0000000000001000
[ 9849.502516] FS:  00007e36cbe94740(0000) GS:ffff88824a899000(0000) knlGS:0000000000000000
[ 9849.502996] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9849.503810] CR2: 000000c0002b0000 CR3: 000000011bbf6004 CR4: 0000000000772ef0
[ 9849.504459] PKRU: 55555554
[ 9849.504626] Call Trace:
[ 9849.505242]  <TASK>
[ 9849.505379]  netfs_write_begin+0x7c8/0x10a0
[ 9849.505877]  ? __kasan_check_read+0x11/0x20
[ 9849.506384]  ? __pfx_netfs_write_begin+0x10/0x10
[ 9849.507178]  ceph_write_begin+0x8c/0x1c0
[ 9849.507934]  generic_perform_write+0x391/0x8f0
[ 9849.508503]  ? __pfx_generic_perform_write+0x10/0x10
[ 9849.509062]  ? file_update_time_flags+0x19a/0x4b0
[ 9849.509581]  ? ceph_get_caps+0x63/0xf0
[ 9849.510259]  ? ceph_get_caps+0x63/0xf0
[ 9849.510530]  ceph_write_iter+0xe79/0x1ae0
[ 9849.511282]  ? __pfx_ceph_write_iter+0x10/0x10
[ 9849.511839]  ? lock_acquire+0x1ad/0x310
[ 9849.512334]  ? ksys_write+0xf9/0x230
[ 9849.512582]  ? lock_is_held_type+0xaa/0x140
[ 9849.513128]  vfs_write+0x512/0x1110
[ 9849.513634]  ? __fget_files+0x33/0x350
[ 9849.513893]  ? __pfx_vfs_write+0x10/0x10
[ 9849.514143]  ? mutex_lock_nested+0x1b/0x30
[ 9849.514394]  ksys_write+0xf9/0x230
[ 9849.514621]  ? __pfx_ksys_write+0x10/0x10
[ 9849.514887]  ? do_syscall_64+0x25e/0x1520
[ 9849.515122]  ? __kasan_check_read+0x11/0x20
[ 9849.515366]  ? trace_hardirqs_on_prepare+0x178/0x1c0
[ 9849.515655]  __x64_sys_write+0x72/0xd0
[ 9849.515885]  ? trace_hardirqs_on+0x24/0x1c0
[ 9849.516130]  x64_sys_call+0x22f/0x2390
[ 9849.516341]  do_syscall_64+0x12b/0x1520
[ 9849.516545]  ? do_syscall_64+0x27c/0x1520
[ 9849.516783]  ? do_syscall_64+0x27c/0x1520
[ 9849.517003]  ? lock_release+0x318/0x480
[ 9849.517220]  ? __x64_sys_io_getevents+0x143/0x2d0
[ 9849.517479]  ? percpu_ref_put_many.constprop.0+0x8f/0x210
[ 9849.517779]  ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 9849.518073]  ? do_syscall_64+0x25e/0x1520
[ 9849.518291]  ? __kasan_check_read+0x11/0x20
[ 9849.518519]  ? trace_hardirqs_on_prepare+0x178/0x1c0
[ 9849.518799]  ? do_syscall_64+0x27c/0x1520
[ 9849.519024]  ? local_clock_noinstr+0xf/0x120
[ 9849.519262]  ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 9849.519544]  ? do_syscall_64+0x25e/0x1520
[ 9849.519781]  ? __kasan_check_read+0x11/0x20
[ 9849.520008]  ? trace_hardirqs_on_prepare+0x178/0x1c0
[ 9849.520273]  ? do_syscall_64+0x27c/0x1520
[ 9849.520491]  ? trace_hardirqs_on_prepare+0x178/0x1c0
[ 9849.520767]  ? irqentry_exit+0x10c/0x6c0
[ 9849.520984]  ? trace_hardirqs_off+0x86/0x1b0
[ 9849.521224]  ? exc_page_fault+0xab/0x130
[ 9849.521472]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 9849.521766] RIP: 0033:0x7e36cbd14907
[ 9849.521989] Code: 10 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
[ 9849.523057] RSP: 002b:00007ffff2d2a968 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 9849.523484] RAX: ffffffffffffffda RBX: 000000000000e549 RCX: 00007e36cbd14907
[ 9849.523885] RDX: 000000000000e549 RSI: 00005bd797ec6370 RDI: 0000000000000004
[ 9849.524277] RBP: 0000000000000004 R08: 0000000000000047 R09: 00005bd797ec6370
[ 9849.524652] R10: 0000000000000078 R11: 0000000000000246 R12: 0000000000000049
[ 9849.525062] R13: 0000000010781a37 R14: 00005bd797ec6370 R15: 0000000000000000
[ 9849.525447]  </TASK>
[ 9849.525574] Modules linked in: intel_rapl_msr intel_rapl_common intel_uncore_frequency_common intel_pmc_core pmt_telemetry pmt_discovery pmt_class intel_pmc_ssram_telemetry intel_vsec kvm_intel joydev kvm irqbypass ghash_clmulni_intel aesni_intel input_leds rapl mac_hid psmouse vga16fb serio_raw vgastate floppy i2c_piix4 bochs qemu_fw_cfg i2c_smbus pata_acpi sch_fq_codel rbd msr parport_pc ppdev lp parport efi_pstore
[ 9849.529150] ---[ end trace 0000000000000000 ]---
[ 9849.529502] RIP: 0010:folio_unlock+0x85/0xa0
[ 9849.530813] Code: 89 df 31 f6 e8 1c f3 ff ff 48 8b 5d f8 c9 31 c0 31 d2 31 f6 31 ff c3 cc cc cc cc 48 c7 c6 80 6c d9 a7 48 89 df e8 4b b3 10 00 <0f> 0b 48 89 df e8 21 e6 2c 00 eb 9d 0f 1f 40 00 66 66 2e 0f 1f 84
[ 9849.534986] RSP: 0018:ffff8881bb8076b0 EFLAGS: 00010246
[ 9849.536198] RAX: 0000000000000000 RBX: ffffea00070c8980 RCX: 0000000000000000
[ 9849.537718] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 9849.539321] RBP: ffff8881bb8076b8 R08: 0000000000000000 R09: 0000000000000000
[ 9849.540862] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000010782000
[ 9849.542438] R13: ffff8881935de738 R14: ffff88816110d010 R15: 0000000000001000
[ 9849.543996] FS:  00007e36cbe94740(0000) GS:ffff88824b899000(0000) knlGS:0000000000000000
[ 9849.545854] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9849.547092] CR2: 00007e36cb3ff000 CR3: 000000011bbf6006 CR4: 0000000000772ef0
[ 9849.548679] PKRU: 55555554

The race sequence:
1. Read completes -> netfs_read_collection() runs
2. netfs_wake_rreq_flag(rreq, NETFS_RREQ_IN_PROGRESS, ...)
3. netfs_wait_for_read() returns -EFAULT to netfs_write_begin()
4. The netfs_unlock_abandoned_read_pages() unlocks the folio
5. netfs_write_begin() calls folio_unlock(folio) -> VM_BUG_ON_FOLIO()

The key reason of the issue that netfs_unlock_abandoned_read_pages()
doesn't check the flag NETFS_RREQ_NO_UNLOCK_FOLIO and executes
folio_unlock() unconditionally. This patch implements in
netfs_unlock_abandoned_read_pages() logic similar to
netfs_unlock_read_folio().

Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-8-dhowells@redhat.com
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: Ceph Development <ceph-devel@vger.kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/read_retry.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c
index 5ec548b996d65..e10eb5a073326 100644
--- a/fs/netfs/read_retry.c
+++ b/fs/netfs/read_retry.c
@@ -292,8 +292,15 @@ void netfs_unlock_abandoned_read_pages(struct netfs_io_request *rreq)
 			struct folio *folio = folioq_folio(p, slot);
 
 			if (folio && !folioq_is_marked2(p, slot)) {
-				trace_netfs_folio(folio, netfs_folio_trace_abandon);
-				folio_unlock(folio);
+				if (folio->index == rreq->no_unlock_folio &&
+				    test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO,
+					     &rreq->flags)) {
+					_debug("no unlock");
+				} else {
+					trace_netfs_folio(folio,
+						netfs_folio_trace_abandon);
+					folio_unlock(folio);
+				}
 			}
 		}
 	}
-- 
2.53.0

[PATCH 7.0 257/461] netfs: Fix overrun check in netfs_extract_user_iter()

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 0ef37eef83fad3542ee06db2940433ae1a92b39d ]

Fix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills
pages[], then those pages don't get included in the iterator constructed at
the end of the function.  If there was an overfill, memory corruption has
already happened.

Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator")
Closes: https://sashiko.dev/#/patchset/20260427154639.180684-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-11-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/iterator.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c
index 429e4396e1b00..b375567e0520e 100644
--- a/fs/netfs/iterator.c
+++ b/fs/netfs/iterator.c
@@ -72,21 +72,24 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
 			break;
 		}
 
-		if (ret > count) {
-			pr_err("get_pages rc=%zd more than %zu\n", ret, count);
+		if (WARN(ret > count,
+			 "%s: extract_pages overrun %zd > %zu bytes\n",
+			 __func__, ret, count)) {
+			ret = -EIO;
 			break;
 		}
 
-		count -= ret;
-		ret += offset;
-		cur_npages = DIV_ROUND_UP(ret, PAGE_SIZE);
-
-		if (npages + cur_npages > max_pages) {
-			pr_err("Out of bvec array capacity (%u vs %u)\n",
-			       npages + cur_npages, max_pages);
+		cur_npages = DIV_ROUND_UP(offset + ret, PAGE_SIZE);
+		if (WARN(cur_npages > max_pages - npages,
+			 "%s: extract_pages overrun %u > %u pages\n",
+			 __func__, npages + cur_npages, max_pages)) {
+			ret = -EIO;
 			break;
 		}
 
+		count -= ret;
+		ret += offset;
+
 		for (i = 0; i < cur_npages; i++) {
 			len = ret > PAGE_SIZE ? PAGE_SIZE : ret;
 			bvec_set_page(bv + npages + i, *pages++, len - offset, offset);
@@ -97,6 +100,11 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
 		npages += cur_npages;
 	}
 
+	/* Note: Don't try to clean up after EIO.  Either we got no pages, so
+	 * nothing to clean up, or we got a buffer overrun, memory corruption
+	 * and can't trust the stuff in the buffer (a WARN was emitted).
+	 */
+
 	if (ret < 0 && (ret == -ENOMEM || npages == 0)) {
 		for (i = 0; i < npages; i++)
 			unpin_user_page(bv[i].bv_page);
-- 
2.53.0

[PATCH 7.0 258/461] netfs: Fix netfs_invalidate_folio() to clear dirty bit if all changes gone

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 156ac2ec2ee77c44c4eb7439d6d165247ba12247 ]

If a streaming write is made, this will leave the relevant modified folio
in a not-uptodate, but dirty state with a netfs_folio struct hung off of
folio->private indicating the dirty range.  Subsequently truncating the
file such that the dirty data in the folio is removed, but the first part
of the folio theoretically remains will cause the netfs_folio struct to be
discarded... but will leave the dirty flag set.

If the folio is then read via mmap(), netfs_read_folio() will see that the
page is dirty and jump to netfs_read_gaps() to fill in the missing bits.
netfs_read_gaps(), however, expects there to be a netfs_folio struct
present and can oops because truncate removed it.

Fix this by calling folio_cancel_dirty() in netfs_invalidate_folio() in the
event that all the dirty data in the folio is erased (as nfs does).

Also add some tracepoints to log modifications to a dirty page.

This can be reproduced with something like:

    dd if=/dev/zero of=/xfstest.test/foo bs=1M count=1
    umount /xfstest.test
    mount /xfstest.test
    xfs_io -c "w 0xbbbf 0xf96c" \
           -c "truncate 0xbbbf" \
           -c "mmap -r 0xb000 0x11000" \
           -c "mr 0xb000 0x11000" \
           /xfstest.test/foo

with fscaching disabled (otherwise streaming writes are suppressed) and a
change to netfs_perform_write() to disallow streaming writes if the fd is
open O_RDWR:

	if (//(file->f_mode & FMODE_READ) || <--- comment this out
	    netfs_is_cache_enabled(ctx)) {

It should be reproducible even without this change, but if prevents the
above trivial xfs_io command from reproducing it.

Note that the initial dd is important: the file must start out sufficiently
large that the zero-point logic doesn't just clear the gaps because it
knows there's nothing in the file to read yet.  Unmounting and mounting is
needed to clear the pagecache (there are other ways to do that that may
also work).

This was initially reproduced with the generic/522 xfstest on some patches
that remove the FMODE_READ restriction.

Fixes: 9ebff83e6481 ("netfs: Prep to use folio->private for write grouping and streaming write")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-12-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/misc.c              | 6 +++++-
 include/trace/events/netfs.h | 4 ++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c
index 723571ca1b885..24b20e80e9a8a 100644
--- a/fs/netfs/misc.c
+++ b/fs/netfs/misc.c
@@ -263,6 +263,7 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length)
 			/* Move the start of the data. */
 			finfo->dirty_len = fend - iend;
 			finfo->dirty_offset = offset;
+			trace_netfs_folio(folio, netfs_folio_trace_invalidate_front);
 			return;
 		}
 
@@ -271,12 +272,14 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length)
 		 */
 		if (iend >= fend) {
 			finfo->dirty_len = offset - fstart;
+			trace_netfs_folio(folio, netfs_folio_trace_invalidate_tail);
 			return;
 		}
 
 		/* A partial write was split.  The caller has already zeroed
 		 * it, so just absorb the hole.
 		 */
+		trace_netfs_folio(folio, netfs_folio_trace_invalidate_middle);
 	}
 	return;
 
@@ -284,8 +287,9 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length)
 	netfs_put_group(netfs_folio_group(folio));
 	folio_detach_private(folio);
 	folio_clear_uptodate(folio);
+	folio_cancel_dirty(folio);
 	kfree(finfo);
-	return;
+	trace_netfs_folio(folio, netfs_folio_trace_invalidate_all);
 }
 EXPORT_SYMBOL(netfs_invalidate_folio);
 
diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h
index cbe28211106c5..88d814ba1e697 100644
--- a/include/trace/events/netfs.h
+++ b/include/trace/events/netfs.h
@@ -194,6 +194,10 @@
 	EM(netfs_folio_trace_copy_to_cache,	"mark-copy")	\
 	EM(netfs_folio_trace_end_copy,		"end-copy")	\
 	EM(netfs_folio_trace_filled_gaps,	"filled-gaps")	\
+	EM(netfs_folio_trace_invalidate_all,	"inval-all")	\
+	EM(netfs_folio_trace_invalidate_front,	"inval-front")	\
+	EM(netfs_folio_trace_invalidate_middle,	"inval-mid")	\
+	EM(netfs_folio_trace_invalidate_tail,	"inval-tail")	\
 	EM(netfs_folio_trace_kill,		"kill")		\
 	EM(netfs_folio_trace_kill_cc,		"kill-cc")	\
 	EM(netfs_folio_trace_kill_g,		"kill-g")	\
-- 
2.53.0

[PATCH 7.0 259/461] netfs: Defer the emission of trace_netfs_folio()

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit daeb443b92817021c1234e8eded219e164b7c35d ]

Change netfs_perform_write() to keep the netfs_folio trace value in a
variable and emit it later to make it easier to choose the value displayed.
This is a prerequisite for a subsequent patch.

Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-13-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: 7b4dcf1b9455 ("netfs: Fix streaming write being overwritten")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_write.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index c887a30c14d91..a695d5168b2fc 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -150,6 +150,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 	}
 
 	do {
+		enum netfs_folio_trace trace;
 		struct netfs_folio *finfo;
 		struct netfs_group *group;
 		unsigned long long fpos;
@@ -223,7 +224,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			if (unlikely(copied == 0))
 				goto copy_failed;
 			netfs_set_group(folio, netfs_group);
-			trace_netfs_folio(folio, netfs_folio_is_uptodate);
+			trace = netfs_folio_is_uptodate;
 			goto copied;
 		}
 
@@ -239,7 +240,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			folio_zero_segment(folio, offset + copied, flen);
 			__netfs_set_group(folio, netfs_group);
 			folio_mark_uptodate(folio);
-			trace_netfs_folio(folio, netfs_modify_and_clear);
+			trace = netfs_modify_and_clear;
 			goto copied;
 		}
 
@@ -257,7 +258,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			}
 			__netfs_set_group(folio, netfs_group);
 			folio_mark_uptodate(folio);
-			trace_netfs_folio(folio, netfs_whole_folio_modify);
+			trace = netfs_whole_folio_modify;
 			goto copied;
 		}
 
@@ -284,7 +285,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			if (unlikely(copied == 0))
 				goto copy_failed;
 			netfs_set_group(folio, netfs_group);
-			trace_netfs_folio(folio, netfs_just_prefetch);
+			trace = netfs_just_prefetch;
 			goto copied;
 		}
 
@@ -298,7 +299,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			if (offset == 0 && copied == flen) {
 				__netfs_set_group(folio, netfs_group);
 				folio_mark_uptodate(folio);
-				trace_netfs_folio(folio, netfs_streaming_filled_page);
+				trace = netfs_streaming_filled_page;
 				goto copied;
 			}
 
@@ -313,7 +314,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			finfo->dirty_len = copied;
 			folio_attach_private(folio, (void *)((unsigned long)finfo |
 							     NETFS_FOLIO_INFO));
-			trace_netfs_folio(folio, netfs_streaming_write);
+			trace = netfs_streaming_write;
 			goto copied;
 		}
 
@@ -333,9 +334,9 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 					folio_detach_private(folio);
 				folio_mark_uptodate(folio);
 				kfree(finfo);
-				trace_netfs_folio(folio, netfs_streaming_cont_filled_page);
+				trace = netfs_streaming_cont_filled_page;
 			} else {
-				trace_netfs_folio(folio, netfs_streaming_write_cont);
+				trace = netfs_streaming_write_cont;
 			}
 			goto copied;
 		}
@@ -351,6 +352,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 		continue;
 
 	copied:
+		trace_netfs_folio(folio, trace);
 		flush_dcache_folio(folio);
 
 		/* Update the inode size if we moved the EOF marker */
-- 
2.53.0

[PATCH 7.0 260/461] netfs: Fix streaming write being overwritten

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 7b4dcf1b9455a6e52ac7478b4057dbe10359576d ]

In order to avoid reading whilst writing, netfslib will allow "streaming
writes" in which dirty data is stored directly into folios without reading
them first.  Such folios are marked dirty but may not be marked uptodate.
If a folio is entirely written by a streaming write, uptodate will be set,
otherwise it will have a netfs_folio struct attached to ->private recording
the dirty region.

In the event that a partially written streaming write page is to be
overwritten entirely by a single write(), netfs_perform_write() will try to
copy over it, but doesn't discard the netfs_folio if it succeeds; further,
it doesn't correctly handle a partial copy that overwrites some of the
dirty data.

Fix this by the following:

 (1) If the folio is successfully overwritten, free the netfs_folio struct
     before marking the page uptodate.

 (2) If the copy to the folio partially fails, but short of the dirty data,
     just ignore the copy.

 (3) If the copy partially fails and overwrites some of the dirty data,
     accept the copy, update the netfs_folio struct to record the new data.
     If the folio is now filled, free the netfs_folio and set uptodate,
     otherwise return a partial write.

Found with:

	fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \
	  /xfstest.test/junk --replay-ops=junk.fsxops

using the following as junk.fsxops:

	truncate 0x0 0 0x927c0
	write 0x63fb8 0x53c8 0
	copy_range 0xb704 0x19b9 0x24429 0x79380
	write 0x2402b 0x144a2 0x90660 *
	write 0x204d5 0x140a0 0x927c0 *
	copy_range 0x1f72c 0x137d0 0x7a906 0x927c0 *
	read 0x00000 0x20000 0x9157c
	read 0x20000 0x20000 0x9157c
	read 0x40000 0x20000 0x9157c
	read 0x60000 0x20000 0x9157c
	read 0x7e1a0 0xcfb9 0x9157c

on cifs with the default cache option.

It shows folio 0x24 misbehaving if the FMODE_READ check is commented out in
netfs_perform_write():

		if (//(file->f_mode & FMODE_READ) ||
		    netfs_is_cache_enabled(ctx)) {

and no fscache.  This was initially found with the generic/522 xfstest.

Fixes: 8f52de0077ba ("netfs: Reduce number of conditional branches in netfs_perform_write()")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-14-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_write.c    | 47 ++++++++++++++++++++++++++----------
 include/trace/events/netfs.h |  3 +++
 2 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index a695d5168b2fc..0ff4c790ae263 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -247,18 +247,38 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 		/* See if we can write a whole folio in one go. */
 		if (!maybe_trouble && offset == 0 && part >= flen) {
 			copied = copy_folio_from_iter_atomic(folio, offset, part, iter);
-			if (unlikely(copied == 0))
+			if (likely(copied == part)) {
+				if (finfo) {
+					trace = netfs_whole_folio_modify_filled;
+					goto folio_now_filled;
+				}
+				__netfs_set_group(folio, netfs_group);
+				folio_mark_uptodate(folio);
+				trace = netfs_whole_folio_modify;
+				goto copied;
+			}
+			if (copied == 0)
 				goto copy_failed;
-			if (unlikely(copied < part)) {
+			if (!finfo || copied <= finfo->dirty_offset) {
 				maybe_trouble = true;
 				iov_iter_revert(iter, copied);
 				copied = 0;
 				folio_unlock(folio);
 				goto retry;
 			}
-			__netfs_set_group(folio, netfs_group);
-			folio_mark_uptodate(folio);
-			trace = netfs_whole_folio_modify;
+
+			/* We overwrote some existing dirty data, so we have to
+			 * accept the partial write.
+			 */
+			finfo->dirty_len += finfo->dirty_offset;
+			if (finfo->dirty_len == flen) {
+				trace = netfs_whole_folio_modify_filled_efault;
+				goto folio_now_filled;
+			}
+			if (copied > finfo->dirty_len)
+				finfo->dirty_len = copied;
+			finfo->dirty_offset = 0;
+			trace = netfs_whole_folio_modify_efault;
 			goto copied;
 		}
 
@@ -328,16 +348,10 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 				goto copy_failed;
 			finfo->dirty_len += copied;
 			if (finfo->dirty_offset == 0 && finfo->dirty_len == flen) {
-				if (finfo->netfs_group)
-					folio_change_private(folio, finfo->netfs_group);
-				else
-					folio_detach_private(folio);
-				folio_mark_uptodate(folio);
-				kfree(finfo);
 				trace = netfs_streaming_cont_filled_page;
-			} else {
-				trace = netfs_streaming_write_cont;
+				goto folio_now_filled;
 			}
+			trace = netfs_streaming_write_cont;
 			goto copied;
 		}
 
@@ -351,6 +365,13 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			goto out;
 		continue;
 
+	folio_now_filled:
+		if (finfo->netfs_group)
+			folio_change_private(folio, finfo->netfs_group);
+		else
+			folio_detach_private(folio);
+		folio_mark_uptodate(folio);
+		kfree(finfo);
 	copied:
 		trace_netfs_folio(folio, trace);
 		flush_dcache_folio(folio);
diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h
index 88d814ba1e697..db045135406c9 100644
--- a/include/trace/events/netfs.h
+++ b/include/trace/events/netfs.h
@@ -177,6 +177,9 @@
 	EM(netfs_folio_is_uptodate,		"mod-uptodate")	\
 	EM(netfs_just_prefetch,			"mod-prefetch")	\
 	EM(netfs_whole_folio_modify,		"mod-whole-f")	\
+	EM(netfs_whole_folio_modify_efault,	"mod-whole-f!")	\
+	EM(netfs_whole_folio_modify_filled,	"mod-whole-f+")	\
+	EM(netfs_whole_folio_modify_filled_efault, "mod-whole-f+!") \
 	EM(netfs_modify_and_clear,		"mod-n-clear")	\
 	EM(netfs_streaming_write,		"mod-streamw")	\
 	EM(netfs_streaming_write_cont,		"mod-streamw+")	\
-- 
2.53.0

[PATCH 7.0 261/461] netfs: Fix potential deadlock in write-through mode

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit b6a4ae1634b3ad2aaa05222e53d36da532852faf ]

Fix netfs_advance_writethrough() to always unlock the supplied folio and to
mark it dirty if it isn't yet written to the end.  Unfortunately, it can't
be marked for writeback until the folio is done with as that may cause a
deadlock against mmapped reads and writes.

Even though it has been marked dirty, premature writeback can't occur as
the caller is holding both inode->i_rwsem (which will prevent concurrent
truncation, fallocation, DIO and other writes) and ictx->wb_lock (which
will cause flushing to wait and writeback to skip or wait).

Note that this may be easier to deal with once the queuing of folios is
split from the generation of subrequests.

Fixes: 288ace2f57c9 ("netfs: New writeback implementation")
Closes: https://sashiko.dev/#/patchset/20260427154639.180684-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-15-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/write_issue.c | 39 +++++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 14 deletions(-)

diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
index b0e9690bb90ce..03961622996be 100644
--- a/fs/netfs/write_issue.c
+++ b/fs/netfs/write_issue.c
@@ -414,12 +414,7 @@ static int netfs_write_folio(struct netfs_io_request *wreq,
 	if (streamw)
 		netfs_issue_write(wreq, cache);
 
-	/* Flip the page to the writeback state and unlock.  If we're called
-	 * from write-through, then the page has already been put into the wb
-	 * state.
-	 */
-	if (wreq->origin == NETFS_WRITEBACK)
-		folio_start_writeback(folio);
+	folio_start_writeback(folio);
 	folio_unlock(folio);
 
 	if (fgroup == NETFS_FOLIO_COPY_TO_CACHE) {
@@ -647,29 +642,41 @@ int netfs_advance_writethrough(struct netfs_io_request *wreq, struct writeback_c
 			       struct folio *folio, size_t copied, bool to_page_end,
 			       struct folio **writethrough_cache)
 {
+	int ret;
+
 	_enter("R=%x ic=%zu ws=%u cp=%zu tp=%u",
 	       wreq->debug_id, wreq->buffer.iter.count, wreq->wsize, copied, to_page_end);
 
-	if (!*writethrough_cache) {
-		if (folio_test_dirty(folio))
-			/* Sigh.  mmap. */
-			folio_clear_dirty_for_io(folio);
+	/* The folio is locked. */
 
+	if (*writethrough_cache != folio) {
+		if (*writethrough_cache) {
+			/* Did the folio get moved? */
+			folio_put(*writethrough_cache);
+			*writethrough_cache = NULL;
+		}
 		/* We can make multiple writes to the folio... */
-		folio_start_writeback(folio);
 		if (wreq->len == 0)
 			trace_netfs_folio(folio, netfs_folio_trace_wthru);
 		else
 			trace_netfs_folio(folio, netfs_folio_trace_wthru_plus);
 		*writethrough_cache = folio;
+		folio_get(folio);
 	}
 
 	wreq->len += copied;
-	if (!to_page_end)
+
+	if (!to_page_end) {
+		folio_mark_dirty(folio);
+		folio_unlock(folio);
 		return 0;
+	}
 
+	ret = netfs_write_folio(wreq, wbc, folio);
+	folio_put(*writethrough_cache);
 	*writethrough_cache = NULL;
-	return netfs_write_folio(wreq, wbc, folio);
+	wreq->submitted = wreq->len;
+	return ret;
 }
 
 /*
@@ -683,8 +690,12 @@ ssize_t netfs_end_writethrough(struct netfs_io_request *wreq, struct writeback_c
 
 	_enter("R=%x", wreq->debug_id);
 
-	if (writethrough_cache)
+	if (writethrough_cache) {
+		folio_lock(writethrough_cache);
 		netfs_write_folio(wreq, wbc, writethrough_cache);
+		folio_put(writethrough_cache);
+		wreq->submitted = wreq->len;
+	}
 
 	netfs_end_issue_write(wreq);
 
-- 
2.53.0

[PATCH 7.0 262/461] netfs: Fix read-gaps to remove netfs_folio from filled folio

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit a41168aef634356a9b87ec44349e3c82835700a5 ]

Fix netfs_read_gaps() to remove the netfs_folio record from the folio
record before marking the folio uptodate if it successfully fills the gaps
around the dirty data in a streaming write folio (dirty, but not uptodate).

Found with:

    fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \
        /xfstest.test/junk --replay-ops=junk.fsxops

using the following as junk.fsxops:

    truncate 0x0 0x138b1 0x8b15d *
    write 0x507ee 0x10df7 0x927c0
    write 0x19993 0x10e04 0x927c0 *
    mapwrite 0x66214 0x1a253 0x927c0
    copy_range 0xb704 0x89b9 0x24429 0x79380
    write 0x2402b 0x144a2 0x90660 *
    mapwrite 0x204d5 0x140a0 0x927c0 *
    copy_range 0x1f72c 0x137d0 0x7a906 0x927c0 *
    read 0 0x9157c 0x9157c

on cifs with the default cache option.

It shows folio 0x24 misbehaving if the FMODE_READ check is commented out in
netfs_perform_write():

                if (//(file->f_mode & FMODE_READ) ||
                    netfs_is_cache_enabled(ctx)) {

and no fscache.  This was initially found with the generic/522 xfstest.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-16-dhowells@redhat.com
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_read.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index ebd84a6cc3f09..51f844bfbdff6 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -395,6 +395,7 @@ static int netfs_read_gaps(struct file *file, struct folio *folio)
 {
 	struct netfs_io_request *rreq;
 	struct address_space *mapping = folio->mapping;
+	struct netfs_group *group = netfs_folio_group(folio);
 	struct netfs_folio *finfo = netfs_folio_info(folio);
 	struct netfs_inode *ctx = netfs_inode(mapping->host);
 	struct folio *sink = NULL;
@@ -461,6 +462,12 @@ static int netfs_read_gaps(struct file *file, struct folio *folio)
 
 	ret = netfs_wait_for_read(rreq);
 	if (ret >= 0) {
+		if (group)
+			folio_change_private(folio, group);
+		else
+			folio_detach_private(folio);
+		kfree(finfo);
+		trace_netfs_folio(folio, netfs_folio_trace_filled_gaps);
 		flush_dcache_folio(folio);
 		folio_mark_uptodate(folio);
 	}
@@ -496,10 +503,8 @@ int netfs_read_folio(struct file *file, struct folio *folio)
 	struct netfs_inode *ctx = netfs_inode(mapping->host);
 	int ret;
 
-	if (folio_test_dirty(folio)) {
-		trace_netfs_folio(folio, netfs_folio_trace_read_gaps);
+	if (folio_test_dirty(folio))
 		return netfs_read_gaps(file, folio);
-	}
 
 	_enter("%lx", folio->index);
 
-- 
2.53.0

[PATCH 7.0 263/461] netfs: Fix write streaming disablement if fd open O_RDWR

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 70a7b9193bbbfceaab5974de66834c64ccc875dd ]

In netfs_perform_write(), "write streaming" (the caching of dirty data in
dirty but !uptodate folios) is performed to avoid the need to read data
that is just going to get immediately overwritten.  However, this is/will
be disabled in three circumstances: if the fd is open O_RDWR, if fscache is
in use (as we need to round out the blocks for DIO) or if content
encryption is enabled (again for rounding out purposes).

The idea behind disabling it if the fd is open O_RDWR is that we'd need to
flush the write-streaming page before we could read the data, particularly
through mmap.  But netfs now fills in the gaps if ->read_folio() is called
on the page, so that is unnecessary.  Further, this doesn't actually work
if a separate fd is open for reading.

Fix this by removing the check for O_RDWR, thereby allowing streaming
writes even when we might read.

This caused a number of problems with the generic/522 xfstest, but those
are now fixed.

Fixes: c38f4e96e605 ("netfs: Provide func to copy data to pagecache for buffered write")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-17-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_write.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index 0ff4c790ae263..b606c3bd84bcd 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -204,11 +204,11 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 		}
 
 		/* Decide how we should modify a folio.  We might be attempting
-		 * to do write-streaming, in which case we don't want to a
-		 * local RMW cycle if we can avoid it.  If we're doing local
-		 * caching or content crypto, we award that priority over
-		 * avoiding RMW.  If the file is open readably, then we also
-		 * assume that we may want to read what we wrote.
+		 * to do write-streaming, as we don't want to a local RMW cycle
+		 * if we can avoid it.  If we're doing local caching or content
+		 * crypto, we award that priority over avoiding RMW.  If the
+		 * file is open readably, then we let ->read_folio() fill in
+		 * the gaps.
 		 */
 		finfo = netfs_folio_info(folio);
 		group = netfs_folio_group(folio);
@@ -284,12 +284,9 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 
 		/* We don't want to do a streaming write on a file that loses
 		 * caching service temporarily because the backing store got
-		 * culled and we don't really want to get a streaming write on
-		 * a file that's open for reading as ->read_folio() then has to
-		 * be able to flush it.
+		 * culled.
 		 */
-		if ((file->f_mode & FMODE_READ) ||
-		    netfs_is_cache_enabled(ctx)) {
+		if (netfs_is_cache_enabled(ctx)) {
 			if (finfo) {
 				netfs_stat(&netfs_n_wh_wstream_conflict);
 				goto flush_content;
-- 
2.53.0

[PATCH 7.0 264/461] netfs: Fix early put of sink folio in netfs_read_gaps()

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 3e5dd91b87a8b1450217b56a336bee315f40da7d ]

Fix netfs_read_gaps() to release the sink page it uses after waiting for
the request to complete.  The way the sink page is used is that an
ITER_BVEC-class iterator is created that has the gaps from the target folio
at either end, but has the sink page tiled over the middle so that a single
read op can fill in both gaps.

The bug was found by KASAN detecting a UAF on the generic/075 xfstest in
the cifsd kernel thread that handles reception of data from the TCP socket:

 BUG: KASAN: use-after-free in _copy_to_iter+0x48a/0xa20
 Write of size 885 at addr ffff888107f92000 by task cifsd/1285
 CPU: 2 UID: 0 PID: 1285 Comm: cifsd Not tainted 7.0.0 #6 PREEMPT(lazy)
 Call Trace:
  dump_stack_lvl+0x5d/0x80
  print_report+0x17f/0x4f1
  kasan_report+0x100/0x1e0
  kasan_check_range+0x10f/0x1e0
  __asan_memcpy+0x3c/0x60
  _copy_to_iter+0x48a/0xa20
  __skb_datagram_iter+0x2c9/0x430
  skb_copy_datagram_iter+0x6e/0x160
  tcp_recvmsg_locked+0xce0/0x1130
  tcp_recvmsg+0xeb/0x300
  inet_recvmsg+0xcf/0x3a0
  sock_recvmsg+0xea/0x100
  cifs_readv_from_socket+0x3a6/0x4d0 [cifs]
  cifs_read_iter_from_socket+0xdd/0x130 [cifs]
  cifs_readv_receive+0xaad/0xb10 [cifs]
  cifs_demultiplex_thread+0x1148/0x1740 [cifs]
  kthread+0x1cf/0x210

Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Reported-by: Steve French <sfrench@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-18-dhowells@redhat.com
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_read.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 51f844bfbdff6..e7ad511e494cc 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -457,9 +457,6 @@ static int netfs_read_gaps(struct file *file, struct folio *folio)
 
 	netfs_read_to_pagecache(rreq, NULL);
 
-	if (sink)
-		folio_put(sink);
-
 	ret = netfs_wait_for_read(rreq);
 	if (ret >= 0) {
 		if (group)
@@ -471,6 +468,9 @@ static int netfs_read_gaps(struct file *file, struct folio *folio)
 		flush_dcache_folio(folio);
 		folio_mark_uptodate(folio);
 	}
+
+	if (sink)
+		folio_put(sink);
 	folio_unlock(folio);
 	netfs_put_request(rreq, netfs_rreq_trace_put_return);
 	return ret < 0 ? ret : 0;
-- 
2.53.0

[PATCH 7.0 265/461] netfs: Fix leak of request in netfs_write_begin() error handling

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 5046a34f0643441f05b0253ea64e1a3af87efe14 ]

Fix netfs_write_begin() to not leak our ref on the request in the event
that we get an error from netfs_wait_for_read().

Fixes: 4090b31422a6 ("netfs: Add a function to consolidate beginning a read")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-19-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_read.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index e7ad511e494cc..004d426c02b41 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -687,9 +687,9 @@ int netfs_write_begin(struct netfs_inode *ctx,
 
 	netfs_read_to_pagecache(rreq, NULL);
 	ret = netfs_wait_for_read(rreq);
+	netfs_put_request(rreq, netfs_rreq_trace_put_return);
 	if (ret < 0)
 		goto error;
-	netfs_put_request(rreq, netfs_rreq_trace_put_return);
 
 have_folio:
 	ret = folio_wait_private_2_killable(folio);
-- 
2.53.0

[PATCH 7.0 266/461] netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit dbe556972100fabb8e5a1b3d2163831ff07b1e8e ]

netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it
is wanting to unlock and compares that to rreq->no_unlock_folio so that it
doesn't unlock a folio being read for netfs_perform_write() or
netfs_write_begin().

However, given that netfs_unlock_abandoned_read_pages() is called _after_
NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to
dereference is the one specified by ->no_unlock_folio as ownership
immediately reverts to the caller.

Fix this by storing the folio pointer instead and using that rather than
the index.  Also fix netfs_unlock_read_folio() where the same applies.

Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-20-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_read.c | 4 ++--
 fs/netfs/read_collect.c  | 2 +-
 fs/netfs/read_retry.c    | 2 +-
 include/linux/netfs.h    | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 004d426c02b41..83d0b8153e96e 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -670,7 +670,7 @@ int netfs_write_begin(struct netfs_inode *ctx,
 		ret = PTR_ERR(rreq);
 		goto error;
 	}
-	rreq->no_unlock_folio	= folio->index;
+	rreq->no_unlock_folio	= folio;
 	__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);
 
 	ret = netfs_begin_cache_read(rreq, ctx);
@@ -736,7 +736,7 @@ int netfs_prefetch_for_write(struct file *file, struct folio *folio,
 		goto error;
 	}
 
-	rreq->no_unlock_folio = folio->index;
+	rreq->no_unlock_folio = folio;
 	__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);
 	ret = netfs_begin_cache_read(rreq, ctx);
 	if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
diff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c
index 3c9b847885c2a..23660a5901246 100644
--- a/fs/netfs/read_collect.c
+++ b/fs/netfs/read_collect.c
@@ -83,7 +83,7 @@ static void netfs_unlock_read_folio(struct netfs_io_request *rreq,
 	}
 
 just_unlock:
-	if (folio->index == rreq->no_unlock_folio &&
+	if (folio == rreq->no_unlock_folio &&
 	    test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) {
 		_debug("no unlock");
 	} else {
diff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c
index e10eb5a073326..f59a70f3a086b 100644
--- a/fs/netfs/read_retry.c
+++ b/fs/netfs/read_retry.c
@@ -292,7 +292,7 @@ void netfs_unlock_abandoned_read_pages(struct netfs_io_request *rreq)
 			struct folio *folio = folioq_folio(p, slot);
 
 			if (folio && !folioq_is_marked2(p, slot)) {
-				if (folio->index == rreq->no_unlock_folio &&
+				if (folio == rreq->no_unlock_folio &&
 				    test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO,
 					     &rreq->flags)) {
 					_debug("no unlock");
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 4fd1d796ad73b..243c0f7379388 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -252,7 +252,7 @@ struct netfs_io_request {
 	unsigned long long	collected_to;	/* Point we've collected to */
 	unsigned long long	cleaned_to;	/* Position we've cleaned folios to */
 	unsigned long long	abandon_to;	/* Position to abandon folios to */
-	pgoff_t			no_unlock_folio; /* Don't unlock this folio after read */
+	const struct folio	*no_unlock_folio; /* Don't unlock this folio after read */
 	unsigned int		direct_bv_count; /* Number of elements in direct_bv[] */
 	unsigned int		debug_id;
 	unsigned int		rsize;		/* Maximum read size (0 for none) */
-- 
2.53.0

[PATCH 7.0 267/461] netfs: Fix partial invalidation of streaming-write folio

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 6d91acc7fb85d33ea58fca9b964a32a453937f4b ]

In netfs_invalidate_folio(), if the region of a partial invalidation
overlaps the front (but not all) of a dirty write cached in a streaming
write page (dirty, but not uptodate, with the dirty region tracked by a
netfs_folio struct), the function modifies the dirty region - but
incorrectly as it moves the region forward by setting the start to the
start, not the end, of the invalidation region.

Fix this by setting finfo->dirty_offset to the end of the invalidation
region (iend).

Fixes: cce6bfa6ca0e ("netfs: Fix trimming of streaming-write folios in netfs_inval_folio()")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-21-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/misc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c
index 24b20e80e9a8a..5d554512ed23a 100644
--- a/fs/netfs/misc.c
+++ b/fs/netfs/misc.c
@@ -262,7 +262,7 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length)
 				goto erase_completely;
 			/* Move the start of the data. */
 			finfo->dirty_len = fend - iend;
-			finfo->dirty_offset = offset;
+			finfo->dirty_offset = iend;
 			trace_netfs_folio(folio, netfs_folio_trace_invalidate_front);
 			return;
 		}
-- 
2.53.0

[PATCH 7.0 268/461] netfs: Fix folio->private handling in netfs_perform_write()

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit ccde2ac757c713535b224233a296de40efe5212d ]

Under some circumstances, netfs_perform_write() doesn't correctly
manipulate folio->private between NULL, NETFS_FOLIO_COPY_TO_CACHE, pointing
to a group and pointing to a netfs_folio struct, leading to potential
multiple attachments of private data with associated folio ref leaks and
also leaks of netfs_folio structs or netfs_group refs.

Fix this by consolidating the place at which a folio is marked uptodate in
one place and having that look at what's attached to folio->private and
decide how to clean it up and then set the new group.  Also, the content
shouldn't be flushed if group is NULL, even if a group is specified in the
netfs_group parameter, as that would be the case for a new folio.  A
filesystem should always specify netfs_group or never specify netfs_group.

The Sashiko auto-review tool noted that it was theoretically possible that
the fpos >= ctx->zero_point section might leak if it modified a streaming
write folio.  This is unlikely, but with a network filesystem, third party
changes can happen.  It also pointed out that __netfs_set_group() would
leak if called multiple times on the same folio from the "whole folio
modify section".

Fixes: 8f52de0077ba ("netfs: Reduce number of conditional branches in netfs_perform_write()")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-22-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_write.c    | 134 +++++++++++++++++++++--------------
 include/trace/events/netfs.h |   1 +
 2 files changed, 82 insertions(+), 53 deletions(-)

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index b606c3bd84bcd..dee10570383bb 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -13,24 +13,6 @@
 #include <linux/pagevec.h>
 #include "internal.h"
 
-static void __netfs_set_group(struct folio *folio, struct netfs_group *netfs_group)
-{
-	if (netfs_group)
-		folio_attach_private(folio, netfs_get_group(netfs_group));
-}
-
-static void netfs_set_group(struct folio *folio, struct netfs_group *netfs_group)
-{
-	void *priv = folio_get_private(folio);
-
-	if (unlikely(priv != netfs_group)) {
-		if (netfs_group && (!priv || priv == NETFS_FOLIO_COPY_TO_CACHE))
-			folio_attach_private(folio, netfs_get_group(netfs_group));
-		else if (!netfs_group && priv == NETFS_FOLIO_COPY_TO_CACHE)
-			folio_detach_private(folio);
-	}
-}
-
 /*
  * Grab a folio for writing and lock it.  Attempt to allocate as large a folio
  * as possible to hold as much of the remaining length as possible in one go.
@@ -158,6 +140,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 		size_t offset;	/* Offset into pagecache folio */
 		size_t part;	/* Bytes to write to folio */
 		size_t copied;	/* Bytes copied from user */
+		void *priv;
 
 		offset = pos & (max_chunk - 1);
 		part = min(max_chunk - offset, iov_iter_count(iter));
@@ -203,6 +186,25 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			goto error_folio_unlock;
 		}
 
+		finfo = netfs_folio_info(folio);
+		group = netfs_folio_group(folio);
+
+		/* If the requested group differs from the group set on the
+		 * page, then we need to flush out the folio if it has a group
+		 * set (ie. is non-NULL).  Note that COPY_TO_CACHE is a special
+		 * case, being a netfs annotation rather than an actual group.
+		 *
+		 * The filesystem isn't permitted to mix writes with groups and
+		 * writes without groups as the NULL group is used to indicate
+		 * that no group is set.
+		 */
+		if (unlikely(group != netfs_group) &&
+		    group != NETFS_FOLIO_COPY_TO_CACHE &&
+		    group) {
+			WARN_ON_ONCE(!netfs_group);
+			goto flush_content;
+		}
+
 		/* Decide how we should modify a folio.  We might be attempting
 		 * to do write-streaming, as we don't want to a local RMW cycle
 		 * if we can avoid it.  If we're doing local caching or content
@@ -210,22 +212,14 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 		 * file is open readably, then we let ->read_folio() fill in
 		 * the gaps.
 		 */
-		finfo = netfs_folio_info(folio);
-		group = netfs_folio_group(folio);
-
-		if (unlikely(group != netfs_group) &&
-		    group != NETFS_FOLIO_COPY_TO_CACHE)
-			goto flush_content;
-
 		if (folio_test_uptodate(folio)) {
 			if (mapping_writably_mapped(mapping))
 				flush_dcache_folio(folio);
 			copied = copy_folio_from_iter_atomic(folio, offset, part, iter);
 			if (unlikely(copied == 0))
 				goto copy_failed;
-			netfs_set_group(folio, netfs_group);
 			trace = netfs_folio_is_uptodate;
-			goto copied;
+			goto copied_uptodate;
 		}
 
 		/* If the page is above the zero-point then we assume that the
@@ -238,24 +232,22 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			if (unlikely(copied == 0))
 				goto copy_failed;
 			folio_zero_segment(folio, offset + copied, flen);
-			__netfs_set_group(folio, netfs_group);
-			folio_mark_uptodate(folio);
-			trace = netfs_modify_and_clear;
-			goto copied;
+			if (finfo)
+				trace = netfs_modify_and_clear_rm_finfo;
+			else
+				trace = netfs_modify_and_clear;
+			goto mark_uptodate;
 		}
 
 		/* See if we can write a whole folio in one go. */
 		if (!maybe_trouble && offset == 0 && part >= flen) {
 			copied = copy_folio_from_iter_atomic(folio, offset, part, iter);
 			if (likely(copied == part)) {
-				if (finfo) {
+				if (finfo)
 					trace = netfs_whole_folio_modify_filled;
-					goto folio_now_filled;
-				}
-				__netfs_set_group(folio, netfs_group);
-				folio_mark_uptodate(folio);
-				trace = netfs_whole_folio_modify;
-				goto copied;
+				else
+					trace = netfs_whole_folio_modify;
+				goto mark_uptodate;
 			}
 			if (copied == 0)
 				goto copy_failed;
@@ -273,7 +265,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			finfo->dirty_len += finfo->dirty_offset;
 			if (finfo->dirty_len == flen) {
 				trace = netfs_whole_folio_modify_filled_efault;
-				goto folio_now_filled;
+				goto mark_uptodate;
 			}
 			if (copied > finfo->dirty_len)
 				finfo->dirty_len = copied;
@@ -301,11 +293,11 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			copied = copy_folio_from_iter_atomic(folio, offset, part, iter);
 			if (unlikely(copied == 0))
 				goto copy_failed;
-			netfs_set_group(folio, netfs_group);
 			trace = netfs_just_prefetch;
-			goto copied;
+			goto copied_uptodate;
 		}
 
+		/* Do a streaming write on a folio that has nothing in it yet. */
 		if (!finfo) {
 			ret = -EIO;
 			if (WARN_ON(folio_get_private(folio)))
@@ -314,10 +306,8 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			if (unlikely(copied == 0))
 				goto copy_failed;
 			if (offset == 0 && copied == flen) {
-				__netfs_set_group(folio, netfs_group);
-				folio_mark_uptodate(folio);
 				trace = netfs_streaming_filled_page;
-				goto copied;
+				goto mark_uptodate;
 			}
 
 			finfo = kzalloc_obj(*finfo);
@@ -346,7 +336,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			finfo->dirty_len += copied;
 			if (finfo->dirty_offset == 0 && finfo->dirty_len == flen) {
 				trace = netfs_streaming_cont_filled_page;
-				goto folio_now_filled;
+				goto mark_uptodate;
 			}
 			trace = netfs_streaming_write_cont;
 			goto copied;
@@ -362,13 +352,36 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			goto out;
 		continue;
 
-	folio_now_filled:
-		if (finfo->netfs_group)
-			folio_change_private(folio, finfo->netfs_group);
-		else
-			folio_detach_private(folio);
+		/* Mark a folio as being up to data when we've filled it
+		 * completely.  If the folio has a group attached, then it must
+		 * be the same group, otherwise we should have flushed it out
+		 * above.  We have to get rid of the netfs_folio struct if
+		 * there was one.
+		 */
+	mark_uptodate:
 		folio_mark_uptodate(folio);
-		kfree(finfo);
+
+	copied_uptodate:
+		priv = folio_get_private(folio);
+		if (likely(priv == netfs_group)) {
+			/* Already set correctly; no change required. */
+		} else if (priv == NETFS_FOLIO_COPY_TO_CACHE) {
+			if (!netfs_group)
+				folio_detach_private(folio);
+			else
+				folio_change_private(folio, netfs_get_group(netfs_group));
+		} else if (!priv) {
+			folio_attach_private(folio, netfs_get_group(netfs_group));
+		} else {
+			WARN_ON_ONCE(!finfo);
+			if (netfs_group)
+				/* finfo->netfs_group has a ref */
+				folio_change_private(folio, netfs_group);
+			else
+				folio_detach_private(folio);
+			kfree(finfo);
+		}
+
 	copied:
 		trace_netfs_folio(folio, trace);
 		flush_dcache_folio(folio);
@@ -531,6 +544,7 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr
 	struct inode *inode = file_inode(file);
 	struct netfs_inode *ictx = netfs_inode(inode);
 	vm_fault_t ret = VM_FAULT_NOPAGE;
+	void *priv;
 	int err;
 
 	_enter("%lx", folio->index);
@@ -551,7 +565,9 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr
 	}
 
 	group = netfs_folio_group(folio);
-	if (group != netfs_group && group != NETFS_FOLIO_COPY_TO_CACHE) {
+	if (group &&
+	    group != netfs_group &&
+	    group != NETFS_FOLIO_COPY_TO_CACHE) {
 		folio_unlock(folio);
 		err = filemap_fdatawrite_range(mapping,
 					       folio_pos(folio),
@@ -573,7 +589,19 @@ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_gr
 		trace_netfs_folio(folio, netfs_folio_trace_mkwrite_plus);
 	else
 		trace_netfs_folio(folio, netfs_folio_trace_mkwrite);
-	netfs_set_group(folio, netfs_group);
+
+	priv = folio_get_private(folio);
+	if (priv != netfs_group) {
+		if (!netfs_group && priv == NETFS_FOLIO_COPY_TO_CACHE)
+			folio_detach_private(folio);
+		else if (netfs_group && priv == NETFS_FOLIO_COPY_TO_CACHE)
+			folio_change_private(folio, netfs_get_group(netfs_group));
+		else if (netfs_group && !priv)
+			folio_attach_private(folio, netfs_get_group(netfs_group));
+		else
+			WARN_ON_ONCE(1);
+	}
+
 	file_update_time(file);
 	set_bit(NETFS_ICTX_MODIFIED_ATTR, &ictx->flags);
 	if (ictx->ops->post_modify)
diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h
index db045135406c9..3fe3980902c24 100644
--- a/include/trace/events/netfs.h
+++ b/include/trace/events/netfs.h
@@ -181,6 +181,7 @@
 	EM(netfs_whole_folio_modify_filled,	"mod-whole-f+")	\
 	EM(netfs_whole_folio_modify_filled_efault, "mod-whole-f+!") \
 	EM(netfs_modify_and_clear,		"mod-n-clear")	\
+	EM(netfs_modify_and_clear_rm_finfo,	"mod-n-clear+")	\
 	EM(netfs_streaming_write,		"mod-streamw")	\
 	EM(netfs_streaming_write_cont,		"mod-streamw+")	\
 	EM(netfs_flush_content,			"flush")	\
-- 
2.53.0

[PATCH 7.0 269/461] netfs: Fix netfs_read_folio() to wait on writeback

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit ded0c6f1606061148c202825f7e53d711f9f84cf ]

Fix netfs_read_folio() to wait for an ongoing writeback to complete so that
it can trust the dirty flag and whatever is attached to folio->private
(folio->private may get cleaned up by the collector before it clears the
writeback flag).

Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-23-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/netfs/buffered_read.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 83d0b8153e96e..76d0f6a29abab 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -503,6 +503,8 @@ int netfs_read_folio(struct file *file, struct folio *folio)
 	struct netfs_inode *ctx = netfs_inode(mapping->host);
 	int ret;
 
+	folio_wait_writeback(folio);
+
 	if (folio_test_dirty(folio))
 		return netfs_read_gaps(file, folio);
 
-- 
2.53.0

[PATCH 7.0 377/461] cifs: Fix undefined variables

[Greg Kroah-Hartman]

7.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

[ Upstream commit 8cf8b5ae8e093132b0dce0a932af10c9ef077936 ]

Fix a couple of undefined variables introduced by the patch to fix tearing
on ->remote_i_size and ->zero_point.  For some reason, make W=1 with gcc
doesn't give undefined variable warnings (but clang does).

Fixes: 2c8f4742bb76 ("netfs: Fix potential for tearing in ->remote_i_size and ->zero_point")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202605031459.eX5UbO3K-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202605021450.ca5QGqLH-lkp@intel.com/
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: Christian Brauner <brauner@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/client/cifsfs.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index db6062dcbb3ec..386b0d43f064f 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -1339,7 +1339,7 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
 	struct cifsFileInfo *smb_file_src = src_file->private_data;
 	struct cifsFileInfo *smb_file_target = dst_file->private_data;
 	struct cifs_tcon *target_tcon, *src_tcon;
-	unsigned long long i_size, old_size, new_size, zero_point;
+	unsigned long long i_size, new_size;
 	unsigned long long destend, fstart, fend;
 	unsigned int xid;
 	int rc;
@@ -1407,7 +1407,7 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
 		goto unlock;
 
 	spin_lock(&target_inode->i_lock);
-	if (fend > zero_point)
+	if (fend > target_cifsi->netfs._zero_point)
 		netfs_write_zero_point(target_inode, fend + 1);
 	i_size = target_inode->i_size;
 	spin_unlock(&target_inode->i_lock);
@@ -1422,7 +1422,7 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off,
 	if (target_tcon->ses->server->ops->duplicate_extents) {
 		rc = target_tcon->ses->server->ops->duplicate_extents(xid,
 			smb_file_src, smb_file_target, off, len, destoff);
-		if (rc == 0 && new_size > old_size) {
+		if (rc == 0 && new_size > i_size) {
 			truncate_setsize(target_inode, new_size);
 			fscache_resize_cookie(cifs_inode_cookie(target_inode),
 					      new_size);
-- 
2.53.0