[PATCH v13 8/8] netfs: Set subrequest->source at alloc before trace emission

From: David Howells

Date: Wed Sep 09 2026 - 03:25:23 EST


Set subrequest->source in netfs_alloc_subrequest() before we emit the trace
line indicating we allocated the subrequest. Note that this requires the
allocation of the subreq in netfs_read_to_pagecache() to be pushed to after
the decision about what sort of subreq it should be.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Paulo Alcantara <pc@xxxxxxxxxxxxx>
cc: netfs@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
cc: linux-mm@xxxxxxxxx
---
fs/netfs/buffered_read.c | 4 ++--
fs/netfs/direct_read.c | 3 +--
fs/netfs/internal.h | 3 ++-
fs/netfs/objects.c | 4 +++-
fs/netfs/read_retry.c | 3 +--
fs/netfs/read_single.c | 3 +--
fs/netfs/write_issue.c | 3 +--
fs/netfs/write_retry.c | 3 +--
8 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 887d45f3745a..68496e1a171f 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -276,10 +276,10 @@ static void netfs_read_to_pagecache(struct netfs_io_request *rreq)

do {
struct netfs_io_subrequest *subreq;
- enum netfs_io_source source = NETFS_SOURCE_UNKNOWN;
+ enum netfs_io_source source;
ssize_t slice;

- subreq = netfs_alloc_subrequest(rreq);
+ subreq = netfs_alloc_subrequest(rreq, NETFS_SOURCE_UNKNOWN);
if (!subreq) {
ret = -ENOMEM;
break;
diff --git a/fs/netfs/direct_read.c b/fs/netfs/direct_read.c
index 5405e108b7a3..8c15f3079723 100644
--- a/fs/netfs/direct_read.c
+++ b/fs/netfs/direct_read.c
@@ -55,7 +55,7 @@ static void netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq)
struct netfs_io_subrequest *subreq;
ssize_t slice;

- subreq = netfs_alloc_subrequest(rreq);
+ subreq = netfs_alloc_subrequest(rreq, NETFS_DOWNLOAD_FROM_SERVER);
if (!subreq) {
/* Stash the error in the request if there's not
* already an error set.
@@ -64,7 +64,6 @@ static void netfs_dispatch_unbuffered_reads(struct netfs_io_request *rreq)
break;
}

- subreq->source = NETFS_DOWNLOAD_FROM_SERVER;
subreq->start = start;
subreq->len = size;

diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h
index d579c5d79609..4891e6e3c5db 100644
--- a/fs/netfs/internal.h
+++ b/fs/netfs/internal.h
@@ -92,7 +92,8 @@ void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace
void netfs_clear_subrequests(struct netfs_io_request *rreq);
void netfs_put_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what);
void netfs_put_failed_request(struct netfs_io_request *rreq);
-struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq);
+struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq,
+ enum netfs_io_source source);

static inline void netfs_see_request(struct netfs_io_request *rreq,
enum netfs_rreq_ref_trace what)
diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c
index 3460aa1c4af1..9c6ea718692a 100644
--- a/fs/netfs/objects.c
+++ b/fs/netfs/objects.c
@@ -207,7 +207,8 @@ void netfs_put_failed_request(struct netfs_io_request *rreq)
/*
* Allocate and partially initialise an I/O request structure.
*/
-struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
+struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq,
+ enum netfs_io_source source)
{
struct netfs_io_subrequest *subreq;
mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
@@ -224,6 +225,7 @@ struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq
INIT_WORK(&subreq->work, NULL);
INIT_LIST_HEAD(&subreq->rreq_link);
refcount_set(&subreq->ref, 2);
+ subreq->source = source;
subreq->rreq = rreq;
subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
diff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c
index 46810d29f0c0..396a05432a7e 100644
--- a/fs/netfs/read_retry.c
+++ b/fs/netfs/read_retry.c
@@ -195,12 +195,11 @@ static void netfs_retry_read_subrequests(struct netfs_io_request *rreq)
* and insert them after.
*/
do {
- subreq = netfs_alloc_subrequest(rreq);
+ subreq = netfs_alloc_subrequest(rreq, NETFS_DOWNLOAD_FROM_SERVER);
if (!subreq) {
subreq = to;
goto abandon_after;
}
- subreq->source = NETFS_DOWNLOAD_FROM_SERVER;
subreq->start = start;
subreq->len = len;
subreq->stream_nr = stream->stream_nr;
diff --git a/fs/netfs/read_single.c b/fs/netfs/read_single.c
index ccb5fc809d99..81295c055ced 100644
--- a/fs/netfs/read_single.c
+++ b/fs/netfs/read_single.c
@@ -92,11 +92,10 @@ static int netfs_single_dispatch_read(struct netfs_io_request *rreq)
struct netfs_io_subrequest *subreq;
int ret = 0;

- subreq = netfs_alloc_subrequest(rreq);
+ subreq = netfs_alloc_subrequest(rreq, NETFS_SOURCE_UNKNOWN);
if (!subreq)
return -ENOMEM;

- subreq->source = NETFS_SOURCE_UNKNOWN;
subreq->start = 0;
subreq->len = rreq->len;
subreq->io_iter = rreq->buffer.iter;
diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
index 9a528da4bf9f..e7cb496f6324 100644
--- a/fs/netfs/write_issue.c
+++ b/fs/netfs/write_issue.c
@@ -168,10 +168,9 @@ void netfs_prepare_write(struct netfs_io_request *wreq,
wreq_iter->folioq_slot >= folioq_nr_slots(wreq_iter->folioq))
rolling_buffer_make_space(&wreq->buffer, wreq->gfp);

- subreq = netfs_alloc_subrequest(wreq);
+ subreq = netfs_alloc_subrequest(wreq, stream->source);
if (!subreq)
return;
- subreq->source = stream->source;
subreq->start = start;
subreq->stream_nr = stream->stream_nr;
subreq->io_iter = *wreq_iter;
diff --git a/fs/netfs/write_retry.c b/fs/netfs/write_retry.c
index 6cd584242af2..d7d5348496fc 100644
--- a/fs/netfs/write_retry.c
+++ b/fs/netfs/write_retry.c
@@ -149,8 +149,7 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq,
* and insert them after.
*/
do {
- subreq = netfs_alloc_subrequest(wreq);
- subreq->source = to->source;
+ subreq = netfs_alloc_subrequest(wreq, stream->source);
subreq->start = start;
subreq->stream_nr = to->stream_nr;
subreq->retry_count = 1;