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 cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.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 cca9ac43c077..5ec548b996d6 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 29489a23a220..32735abfa03f 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;