Merge patch series "netfs: Miscellaneous fixes"

David Howells <dhowells@redhat.com> says:

Here are some miscellaneous fixes and changes for netfslib:

 (1) Fix a number of read-retry hangs, including:

     (a) Incorrect getting/putting of references on subreqs as we retry
     	 them.

     (b) Failure to track whether a last old subrequest in a retried set is
     	 superfluous.

     (c) Inconsistency in the usage of wait queues used for subrequests
     	 (ie. using clear_and_wake_up_bit() whilst waiting on a private
     	 waitqueue).

     	 (Note that waitqueue consistency also needs looking at for
     	 netfs_io_request structs.)

 (2) Add stats counters for retries and publish in /proc/fs/netfs/stats.
     This is not a fix per se, but is useful in debugging and shouldn't
     otherwise change the operation of the code.

 (3) Fix the ordering of queuing subrequests with respect to setting the
     request flag that says we've now queued them all.

* patches from https://lore.kernel.org/r/20250212222402.3618494-1-dhowells@redhat.com:
  netfs: Fix setting NETFS_RREQ_ALL_QUEUED to be after all subreqs queued
  netfs: Add retry stat counters
  netfs: Fix a number of read-retry hangs

Link: https://lore.kernel.org/r/20250212222402.3618494-1-dhowells@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 13 insertions, 6 deletions

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index f761d44b3436..0d1b6d35ff3b 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -155,8 +155,9 @@ static void netfs_read_cache_to_pagecache(struct netfs_io_request *rreq,
 			netfs_cache_read_terminated, subreq);
 }
 
-static void netfs_issue_read(struct netfs_io_request *rreq,
-			     struct netfs_io_subrequest *subreq)
+static void netfs_queue_read(struct netfs_io_request *rreq,
+			     struct netfs_io_subrequest *subreq,
+			     bool last_subreq)
 {
 	struct netfs_io_stream *stream = &rreq->io_streams[0];
 
@@ -177,8 +178,17 @@ static void netfs_issue_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);
+}
 
+static void netfs_issue_read(struct netfs_io_request *rreq,
+			     struct netfs_io_subrequest *subreq)
+{
 	switch (subreq->source) {
 	case NETFS_DOWNLOAD_FROM_SERVER:
 		rreq->netfs_ops->issue_read(subreq);
@@ -293,11 +303,8 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq)
 		}
 		size -= slice;
 		start += 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);