[PATCH 6.10 083/273] 9p: Fix DIO read through netfs

[PATCH 6.10 083/273] 9p: Fix DIO read through netfs

[Greg Kroah-Hartman]

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

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

From: Dominique Martinet <asmadeus@codewreck.org>

[ Upstream commit e3786b29c54cdae3490b07180a54e2461f42144c ]

If a program is watching a file on a 9p mount, it won't see any change in
size if the file being exported by the server is changed directly in the
source filesystem, presumably because 9p doesn't have change notifications,
and because netfs skips the reads if the file is empty.

Fix this by attempting to read the full size specified when a DIO read is
requested (such as when 9p is operating in unbuffered mode) and dealing
with a short read if the EOF was less than the expected read.

To make this work, filesystems using netfslib must not set
NETFS_SREQ_CLEAR_TAIL if performing a DIO read where that read hit the EOF.
I don't want to mandatorily clear this flag in netfslib for DIO because,
say, ceph might make a read from an object that is not completely filled,
but does not reside at the end of file - and so we need to clear the
excess.

This can be tested by watching an empty file over 9p within a VM (such as
in the ktest framework):

        while true; do read content; if [ -n "$content" ]; then echo $content; break; fi; done < /host/tmp/foo

then writing something into the empty file.  The watcher should immediately
display the file content and break out of the loop.  Without this fix, it
remains in the loop indefinitely.

Fixes: 80105ed2fd27 ("9p: Use netfslib read/write_iter")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218916
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/1229195.1723211769@warthog.procyon.org.uk
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/9p/vfs_addr.c     |  3 ++-
 fs/afs/file.c        |  3 ++-
 fs/ceph/addr.c       |  6 ++++--
 fs/netfs/io.c        | 17 +++++++++++------
 fs/nfs/fscache.c     |  3 ++-
 fs/smb/client/file.c |  3 ++-
 6 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index a97ceb105cd8d..24fdc74caeba4 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -75,7 +75,8 @@ static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
 
 	/* if we just extended the file size, any portion not in
 	 * cache won't be on server and is zeroes */
-	__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+	if (subreq->rreq->origin != NETFS_DIO_READ)
+		__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
 
 	netfs_subreq_terminated(subreq, err ?: total, false);
 }
diff --git a/fs/afs/file.c b/fs/afs/file.c
index c3f0c45ae9a9b..ec1be0091fdb5 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -242,7 +242,8 @@ static void afs_fetch_data_notify(struct afs_operation *op)
 
 	req->error = error;
 	if (subreq) {
-		__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+		if (subreq->rreq->origin != NETFS_DIO_READ)
+			__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
 		netfs_subreq_terminated(subreq, error ?: req->actual_len, false);
 		req->subreq = NULL;
 	} else if (req->done) {
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 73b5a07bf94de..d2194022132ec 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -246,7 +246,8 @@ static void finish_netfs_read(struct ceph_osd_request *req)
 	if (err >= 0) {
 		if (sparse && err > 0)
 			err = ceph_sparse_ext_map_end(op);
-		if (err < subreq->len)
+		if (err < subreq->len &&
+		    subreq->rreq->origin != NETFS_DIO_READ)
 			__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
 		if (IS_ENCRYPTED(inode) && err > 0) {
 			err = ceph_fscrypt_decrypt_extents(inode,
@@ -282,7 +283,8 @@ static bool ceph_netfs_issue_op_inline(struct netfs_io_subrequest *subreq)
 	size_t len;
 	int mode;
 
-	__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+	if (rreq->origin != NETFS_DIO_READ)
+		__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
 	__clear_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags);
 
 	if (subreq->start >= inode->i_size)
diff --git a/fs/netfs/io.c b/fs/netfs/io.c
index f3abc5dfdbc0c..19ec6990dc91e 100644
--- a/fs/netfs/io.c
+++ b/fs/netfs/io.c
@@ -530,7 +530,8 @@ void netfs_subreq_terminated(struct netfs_io_subrequest *subreq,
 
 	if (transferred_or_error == 0) {
 		if (__test_and_set_bit(NETFS_SREQ_NO_PROGRESS, &subreq->flags)) {
-			subreq->error = -ENODATA;
+			if (rreq->origin != NETFS_DIO_READ)
+				subreq->error = -ENODATA;
 			goto failed;
 		}
 	} else {
@@ -601,9 +602,14 @@ netfs_rreq_prepare_read(struct netfs_io_request *rreq,
 			}
 			if (subreq->len > ictx->zero_point - subreq->start)
 				subreq->len = ictx->zero_point - subreq->start;
+
+			/* We limit buffered reads to the EOF, but let the
+			 * server deal with larger-than-EOF DIO/unbuffered
+			 * reads.
+			 */
+			if (subreq->len > rreq->i_size - subreq->start)
+				subreq->len = rreq->i_size - subreq->start;
 		}
-		if (subreq->len > rreq->i_size - subreq->start)
-			subreq->len = rreq->i_size - subreq->start;
 		if (rreq->rsize && subreq->len > rreq->rsize)
 			subreq->len = rreq->rsize;
 
@@ -739,11 +745,10 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync)
 	do {
 		kdebug("submit %llx + %llx >= %llx",
 		       rreq->start, rreq->submitted, rreq->i_size);
-		if (rreq->origin == NETFS_DIO_READ &&
-		    rreq->start + rreq->submitted >= rreq->i_size)
-			break;
 		if (!netfs_rreq_submit_slice(rreq, &io_iter))
 			break;
+		if (test_bit(NETFS_SREQ_NO_PROGRESS, &rreq->flags))
+			break;
 		if (test_bit(NETFS_RREQ_BLOCKED, &rreq->flags) &&
 		    test_bit(NETFS_RREQ_NONBLOCK, &rreq->flags))
 			break;
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index ddc1ee0319554..bc20ba50283c8 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -361,7 +361,8 @@ void nfs_netfs_read_completion(struct nfs_pgio_header *hdr)
 		return;
 
 	sreq = netfs->sreq;
-	if (test_bit(NFS_IOHDR_EOF, &hdr->flags))
+	if (test_bit(NFS_IOHDR_EOF, &hdr->flags) &&
+	    sreq->rreq->origin != NETFS_DIO_READ)
 		__set_bit(NETFS_SREQ_CLEAR_TAIL, &sreq->flags);
 
 	if (hdr->error)
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index 2e3c4d0277dbb..9e4f4e67768b9 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -196,7 +196,8 @@ static void cifs_req_issue_read(struct netfs_io_subrequest *subreq)
 			goto out;
 	}
 
-	__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
+	if (subreq->rreq->origin != NETFS_DIO_READ)
+		__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
 
 	rc = rdata->server->ops->async_readv(rdata);
 out:
-- 
2.43.0

[PATCH 6.10 142/273] cifs: Add a tracepoint to track credits involved in R/W requests

[Greg Kroah-Hartman]

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

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

From: David Howells <dhowells@redhat.com>

[ Upstream commit 519be989717c5bffaed1dc14a439e3872cb4bb8d ]

Add a tracepoint to track the credit changes and server in_flight value
involved in the lifetime of a R/W request, logging it against the
request/subreq debugging ID.  This requires the debugging IDs to be
recorded in the cifs_credits struct.

The tracepoint can be enabled with:

	echo 1 >/sys/kernel/debug/tracing/events/cifs/smb3_rw_credits/enable

Also add a three-state flag to struct cifs_credits to note if we're
interested in determining when the in_flight contribution ends and, if so,
to track whether we've decremented the contribution yet.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: 74c2ab6d653b ("smb/client: avoid possible NULL dereference in cifs_free_subrequest()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/client/cifsglob.h  | 17 +++++++-----
 fs/smb/client/file.c      | 32 ++++++++++++++++++++++-
 fs/smb/client/smb1ops.c   |  2 +-
 fs/smb/client/smb2ops.c   | 42 ++++++++++++++++++++++++++----
 fs/smb/client/smb2pdu.c   | 40 +++++++++++++++++++++++++---
 fs/smb/client/trace.h     | 55 ++++++++++++++++++++++++++++++++++++++-
 fs/smb/client/transport.c |  8 +++---
 7 files changed, 173 insertions(+), 23 deletions(-)

diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index d4bcc7da700c6..0a271b9fbc622 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -290,7 +290,7 @@ struct smb_version_operations {
 	int (*check_receive)(struct mid_q_entry *, struct TCP_Server_Info *,
 			     bool);
 	void (*add_credits)(struct TCP_Server_Info *server,
-			    const struct cifs_credits *credits,
+			    struct cifs_credits *credits,
 			    const int optype);
 	void (*set_credits)(struct TCP_Server_Info *, const int);
 	int * (*get_credits_field)(struct TCP_Server_Info *, const int);
@@ -550,8 +550,8 @@ struct smb_version_operations {
 				size_t *, struct cifs_credits *);
 	/* adjust previously taken mtu credits to request size */
 	int (*adjust_credits)(struct TCP_Server_Info *server,
-			      struct cifs_credits *credits,
-			      const unsigned int payload_size);
+			      struct cifs_io_subrequest *subreq,
+			      unsigned int /*enum smb3_rw_credits_trace*/ trace);
 	/* check if we need to issue closedir */
 	bool (*dir_needs_close)(struct cifsFileInfo *);
 	long (*fallocate)(struct file *, struct cifs_tcon *, int, loff_t,
@@ -848,6 +848,9 @@ static inline void cifs_server_unlock(struct TCP_Server_Info *server)
 struct cifs_credits {
 	unsigned int value;
 	unsigned int instance;
+	unsigned int in_flight_check;
+	unsigned int rreq_debug_id;
+	unsigned int rreq_debug_index;
 };
 
 static inline unsigned int
@@ -873,7 +876,7 @@ has_credits(struct TCP_Server_Info *server, int *credits, int num_credits)
 }
 
 static inline void
-add_credits(struct TCP_Server_Info *server, const struct cifs_credits *credits,
+add_credits(struct TCP_Server_Info *server, struct cifs_credits *credits,
 	    const int optype)
 {
 	server->ops->add_credits(server, credits, optype);
@@ -897,11 +900,11 @@ set_credits(struct TCP_Server_Info *server, const int val)
 }
 
 static inline int
-adjust_credits(struct TCP_Server_Info *server, struct cifs_credits *credits,
-	       const unsigned int payload_size)
+adjust_credits(struct TCP_Server_Info *server, struct cifs_io_subrequest *subreq,
+	       unsigned int /* enum smb3_rw_credits_trace */ trace)
 {
 	return server->ops->adjust_credits ?
-		server->ops->adjust_credits(server, credits, payload_size) : 0;
+		server->ops->adjust_credits(server, subreq, trace) : 0;
 }
 
 static inline __le64
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index 9e4f4e67768b9..b413cfef05422 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -80,6 +80,16 @@ static void cifs_prepare_write(struct netfs_io_subrequest *subreq)
 		return netfs_prepare_write_failed(subreq);
 	}
 
+	wdata->credits.rreq_debug_id = subreq->rreq->debug_id;
+	wdata->credits.rreq_debug_index = subreq->debug_index;
+	wdata->credits.in_flight_check = 1;
+	trace_smb3_rw_credits(wdata->rreq->debug_id,
+			      wdata->subreq.debug_index,
+			      wdata->credits.value,
+			      server->credits, server->in_flight,
+			      wdata->credits.value,
+			      cifs_trace_rw_credits_write_prepare);
+
 #ifdef CONFIG_CIFS_SMB_DIRECT
 	if (server->smbd_conn)
 		subreq->max_nr_segs = server->smbd_conn->max_frmr_depth;
@@ -101,7 +111,7 @@ static void cifs_issue_write(struct netfs_io_subrequest *subreq)
 		goto fail;
 	}
 
-	rc = adjust_credits(wdata->server, &wdata->credits, wdata->subreq.len);
+	rc = adjust_credits(wdata->server, wdata, cifs_trace_rw_credits_issue_write_adjust);
 	if (rc)
 		goto fail;
 
@@ -163,7 +173,18 @@ static bool cifs_clamp_length(struct netfs_io_subrequest *subreq)
 		return false;
 	}
 
+	rdata->credits.in_flight_check = 1;
+	rdata->credits.rreq_debug_id = rreq->debug_id;
+	rdata->credits.rreq_debug_index = subreq->debug_index;
+
+	trace_smb3_rw_credits(rdata->rreq->debug_id,
+			      rdata->subreq.debug_index,
+			      rdata->credits.value,
+			      server->credits, server->in_flight, 0,
+			      cifs_trace_rw_credits_read_submit);
+
 	subreq->len = min_t(size_t, subreq->len, rsize);
+
 #ifdef CONFIG_CIFS_SMB_DIRECT
 	if (server->smbd_conn)
 		subreq->max_nr_segs = server->smbd_conn->max_frmr_depth;
@@ -295,6 +316,15 @@ static void cifs_free_subrequest(struct netfs_io_subrequest *subreq)
 #endif
 	}
 
+	if (rdata->credits.value != 0)
+		trace_smb3_rw_credits(rdata->rreq->debug_id,
+				      rdata->subreq.debug_index,
+				      rdata->credits.value,
+				      rdata->server ? rdata->server->credits : 0,
+				      rdata->server ? rdata->server->in_flight : 0,
+				      -rdata->credits.value,
+				      cifs_trace_rw_credits_free_subreq);
+
 	add_credits_and_wake_if(rdata->server, &rdata->credits, 0);
 	if (rdata->have_xid)
 		free_xid(rdata->xid);
diff --git a/fs/smb/client/smb1ops.c b/fs/smb/client/smb1ops.c
index 212ec6f66ec65..e1f2feb56f45f 100644
--- a/fs/smb/client/smb1ops.c
+++ b/fs/smb/client/smb1ops.c
@@ -108,7 +108,7 @@ cifs_find_mid(struct TCP_Server_Info *server, char *buffer)
 
 static void
 cifs_add_credits(struct TCP_Server_Info *server,
-		 const struct cifs_credits *credits, const int optype)
+		 struct cifs_credits *credits, const int optype)
 {
 	spin_lock(&server->req_lock);
 	server->credits += credits->value;
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index c8e536540895a..7fe59235f0901 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -66,7 +66,7 @@ change_conf(struct TCP_Server_Info *server)
 
 static void
 smb2_add_credits(struct TCP_Server_Info *server,
-		 const struct cifs_credits *credits, const int optype)
+		 struct cifs_credits *credits, const int optype)
 {
 	int *val, rc = -1;
 	int scredits, in_flight;
@@ -94,7 +94,21 @@ smb2_add_credits(struct TCP_Server_Info *server,
 					    server->conn_id, server->hostname, *val,
 					    add, server->in_flight);
 	}
-	WARN_ON_ONCE(server->in_flight == 0);
+	if (credits->in_flight_check > 1) {
+		pr_warn_once("rreq R=%08x[%x] Credits not in flight\n",
+			     credits->rreq_debug_id, credits->rreq_debug_index);
+	} else {
+		credits->in_flight_check = 2;
+	}
+	if (WARN_ON_ONCE(server->in_flight == 0)) {
+		pr_warn_once("rreq R=%08x[%x] Zero in_flight\n",
+			     credits->rreq_debug_id, credits->rreq_debug_index);
+		trace_smb3_rw_credits(credits->rreq_debug_id,
+				      credits->rreq_debug_index,
+				      credits->value,
+				      server->credits, server->in_flight, 0,
+				      cifs_trace_rw_credits_zero_in_flight);
+	}
 	server->in_flight--;
 	if (server->in_flight == 0 &&
 	   ((optype & CIFS_OP_MASK) != CIFS_NEG_OP) &&
@@ -283,16 +297,23 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, size_t size,
 
 static int
 smb2_adjust_credits(struct TCP_Server_Info *server,
-		    struct cifs_credits *credits,
-		    const unsigned int payload_size)
+		    struct cifs_io_subrequest *subreq,
+		    unsigned int /*enum smb3_rw_credits_trace*/ trace)
 {
-	int new_val = DIV_ROUND_UP(payload_size, SMB2_MAX_BUFFER_SIZE);
+	struct cifs_credits *credits = &subreq->credits;
+	int new_val = DIV_ROUND_UP(subreq->subreq.len, SMB2_MAX_BUFFER_SIZE);
 	int scredits, in_flight;
 
 	if (!credits->value || credits->value == new_val)
 		return 0;
 
 	if (credits->value < new_val) {
+		trace_smb3_rw_credits(subreq->rreq->debug_id,
+				      subreq->subreq.debug_index,
+				      credits->value,
+				      server->credits, server->in_flight,
+				      new_val - credits->value,
+				      cifs_trace_rw_credits_no_adjust_up);
 		trace_smb3_too_many_credits(server->CurrentMid,
 				server->conn_id, server->hostname, 0, credits->value - new_val, 0);
 		cifs_server_dbg(VFS, "request has less credits (%d) than required (%d)",
@@ -308,6 +329,12 @@ smb2_adjust_credits(struct TCP_Server_Info *server,
 		in_flight = server->in_flight;
 		spin_unlock(&server->req_lock);
 
+		trace_smb3_rw_credits(subreq->rreq->debug_id,
+				      subreq->subreq.debug_index,
+				      credits->value,
+				      server->credits, server->in_flight,
+				      new_val - credits->value,
+				      cifs_trace_rw_credits_old_session);
 		trace_smb3_reconnect_detected(server->CurrentMid,
 			server->conn_id, server->hostname, scredits,
 			credits->value - new_val, in_flight);
@@ -316,6 +343,11 @@ smb2_adjust_credits(struct TCP_Server_Info *server,
 		return -EAGAIN;
 	}
 
+	trace_smb3_rw_credits(subreq->rreq->debug_id,
+			      subreq->subreq.debug_index,
+			      credits->value,
+			      server->credits, server->in_flight,
+			      new_val - credits->value, trace);
 	server->credits += credits->value - new_val;
 	scredits = server->credits;
 	in_flight = server->in_flight;
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 896147ba6660e..4cd5c33be2a1a 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -4505,8 +4505,15 @@ smb2_readv_callback(struct mid_q_entry *mid)
 	struct TCP_Server_Info *server = rdata->server;
 	struct smb2_hdr *shdr =
 				(struct smb2_hdr *)rdata->iov[0].iov_base;
-	struct cifs_credits credits = { .value = 0, .instance = 0 };
+	struct cifs_credits credits = {
+		.value = 0,
+		.instance = 0,
+		.rreq_debug_id = rdata->rreq->debug_id,
+		.rreq_debug_index = rdata->subreq.debug_index,
+	};
 	struct smb_rqst rqst = { .rq_iov = &rdata->iov[1], .rq_nvec = 1 };
+	unsigned int rreq_debug_id = rdata->rreq->debug_id;
+	unsigned int subreq_debug_index = rdata->subreq.debug_index;
 
 	if (rdata->got_bytes) {
 		rqst.rq_iter	  = rdata->subreq.io_iter;
@@ -4590,10 +4597,16 @@ smb2_readv_callback(struct mid_q_entry *mid)
 		if (rdata->subreq.start < rdata->subreq.rreq->i_size)
 			rdata->result = 0;
 	}
+	trace_smb3_rw_credits(rreq_debug_id, subreq_debug_index, rdata->credits.value,
+			      server->credits, server->in_flight,
+			      0, cifs_trace_rw_credits_read_response_clear);
 	rdata->credits.value = 0;
 	INIT_WORK(&rdata->subreq.work, smb2_readv_worker);
 	queue_work(cifsiod_wq, &rdata->subreq.work);
 	release_mid(mid);
+	trace_smb3_rw_credits(rreq_debug_id, subreq_debug_index, 0,
+			      server->credits, server->in_flight,
+			      credits.value, cifs_trace_rw_credits_read_response_add);
 	add_credits(server, &credits, 0);
 }
 
@@ -4650,7 +4663,7 @@ smb2_async_readv(struct cifs_io_subrequest *rdata)
 				min_t(int, server->max_credits -
 						server->credits, credit_request));
 
-		rc = adjust_credits(server, &rdata->credits, rdata->subreq.len);
+		rc = adjust_credits(server, rdata, cifs_trace_rw_credits_call_readv_adjust);
 		if (rc)
 			goto async_readv_out;
 
@@ -4769,7 +4782,14 @@ smb2_writev_callback(struct mid_q_entry *mid)
 	struct cifs_tcon *tcon = tlink_tcon(wdata->req->cfile->tlink);
 	struct TCP_Server_Info *server = wdata->server;
 	struct smb2_write_rsp *rsp = (struct smb2_write_rsp *)mid->resp_buf;
-	struct cifs_credits credits = { .value = 0, .instance = 0 };
+	struct cifs_credits credits = {
+		.value = 0,
+		.instance = 0,
+		.rreq_debug_id = wdata->rreq->debug_id,
+		.rreq_debug_index = wdata->subreq.debug_index,
+	};
+	unsigned int rreq_debug_id = wdata->rreq->debug_id;
+	unsigned int subreq_debug_index = wdata->subreq.debug_index;
 	ssize_t result = 0;
 	size_t written;
 
@@ -4840,9 +4860,15 @@ smb2_writev_callback(struct mid_q_entry *mid)
 				      tcon->tid, tcon->ses->Suid,
 				      wdata->subreq.start, wdata->subreq.len);
 
+	trace_smb3_rw_credits(rreq_debug_id, subreq_debug_index, wdata->credits.value,
+			      server->credits, server->in_flight,
+			      0, cifs_trace_rw_credits_write_response_clear);
 	wdata->credits.value = 0;
 	cifs_write_subrequest_terminated(wdata, result ?: written, true);
 	release_mid(mid);
+	trace_smb3_rw_credits(rreq_debug_id, subreq_debug_index, 0,
+			      server->credits, server->in_flight,
+			      credits.value, cifs_trace_rw_credits_write_response_add);
 	add_credits(server, &credits, 0);
 }
 
@@ -4972,7 +4998,7 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
 				min_t(int, server->max_credits -
 						server->credits, credit_request));
 
-		rc = adjust_credits(server, &wdata->credits, io_parms->length);
+		rc = adjust_credits(server, wdata, cifs_trace_rw_credits_call_writev_adjust);
 		if (rc)
 			goto async_writev_out;
 
@@ -4997,6 +5023,12 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
 	cifs_small_buf_release(req);
 out:
 	if (rc) {
+		trace_smb3_rw_credits(wdata->rreq->debug_id,
+				      wdata->subreq.debug_index,
+				      wdata->credits.value,
+				      server->credits, server->in_flight,
+				      -(int)wdata->credits.value,
+				      cifs_trace_rw_credits_write_response_clear);
 		add_credits_and_wake_if(wdata->server, &wdata->credits, 0);
 		cifs_write_subrequest_terminated(wdata, rc, true);
 	}
diff --git a/fs/smb/client/trace.h b/fs/smb/client/trace.h
index 36d47ce596317..36d5295c2a6f9 100644
--- a/fs/smb/client/trace.h
+++ b/fs/smb/client/trace.h
@@ -20,6 +20,22 @@
 /*
  * Specify enums for tracing information.
  */
+#define smb3_rw_credits_traces \
+	EM(cifs_trace_rw_credits_call_readv_adjust,	"rd-call-adj") \
+	EM(cifs_trace_rw_credits_call_writev_adjust,	"wr-call-adj") \
+	EM(cifs_trace_rw_credits_free_subreq,		"free-subreq") \
+	EM(cifs_trace_rw_credits_issue_read_adjust,	"rd-issu-adj") \
+	EM(cifs_trace_rw_credits_issue_write_adjust,	"wr-issu-adj") \
+	EM(cifs_trace_rw_credits_no_adjust_up,		"no-adj-up  ") \
+	EM(cifs_trace_rw_credits_old_session,		"old-session") \
+	EM(cifs_trace_rw_credits_read_response_add,	"rd-resp-add") \
+	EM(cifs_trace_rw_credits_read_response_clear,	"rd-resp-clr") \
+	EM(cifs_trace_rw_credits_read_submit,		"rd-submit  ") \
+	EM(cifs_trace_rw_credits_write_prepare,		"wr-prepare ") \
+	EM(cifs_trace_rw_credits_write_response_add,	"wr-resp-add") \
+	EM(cifs_trace_rw_credits_write_response_clear,	"wr-resp-clr") \
+	E_(cifs_trace_rw_credits_zero_in_flight,	"ZERO-IN-FLT")
+
 #define smb3_tcon_ref_traces					      \
 	EM(netfs_trace_tcon_ref_dec_dfs_refer,		"DEC DfsRef") \
 	EM(netfs_trace_tcon_ref_free,			"FRE       ") \
@@ -59,7 +75,8 @@
 #define EM(a, b) a,
 #define E_(a, b) a
 
-enum smb3_tcon_ref_trace { smb3_tcon_ref_traces } __mode(byte);
+enum smb3_rw_credits_trace	{ smb3_rw_credits_traces } __mode(byte);
+enum smb3_tcon_ref_trace	{ smb3_tcon_ref_traces } __mode(byte);
 
 #undef EM
 #undef E_
@@ -71,6 +88,7 @@ enum smb3_tcon_ref_trace { smb3_tcon_ref_traces } __mode(byte);
 #define EM(a, b) TRACE_DEFINE_ENUM(a);
 #define E_(a, b) TRACE_DEFINE_ENUM(a);
 
+smb3_rw_credits_traces;
 smb3_tcon_ref_traces;
 
 #undef EM
@@ -1316,6 +1334,41 @@ TRACE_EVENT(smb3_tcon_ref,
 		      __entry->ref)
 	    );
 
+TRACE_EVENT(smb3_rw_credits,
+	    TP_PROTO(unsigned int rreq_debug_id,
+		     unsigned int subreq_debug_index,
+		     unsigned int subreq_credits,
+		     unsigned int server_credits,
+		     int server_in_flight,
+		     int credit_change,
+		     enum smb3_rw_credits_trace trace),
+	    TP_ARGS(rreq_debug_id, subreq_debug_index, subreq_credits,
+		    server_credits, server_in_flight, credit_change, trace),
+	    TP_STRUCT__entry(
+		    __field(unsigned int, rreq_debug_id)
+		    __field(unsigned int, subreq_debug_index)
+		    __field(unsigned int, subreq_credits)
+		    __field(unsigned int, server_credits)
+		    __field(int,	  in_flight)
+		    __field(int,	  credit_change)
+		    __field(enum smb3_rw_credits_trace, trace)
+			     ),
+	    TP_fast_assign(
+		    __entry->rreq_debug_id	= rreq_debug_id;
+		    __entry->subreq_debug_index	= subreq_debug_index;
+		    __entry->subreq_credits	= subreq_credits;
+		    __entry->server_credits	= server_credits;
+		    __entry->in_flight		= server_in_flight;
+		    __entry->credit_change	= credit_change;
+		    __entry->trace		= trace;
+			   ),
+	    TP_printk("R=%08x[%x] %s cred=%u chg=%d pool=%u ifl=%d",
+		      __entry->rreq_debug_id, __entry->subreq_debug_index,
+		      __print_symbolic(__entry->trace, smb3_rw_credits_traces),
+		      __entry->subreq_credits, __entry->credit_change,
+		      __entry->server_credits, __entry->in_flight)
+	    );
+
 
 #undef EM
 #undef E_
diff --git a/fs/smb/client/transport.c b/fs/smb/client/transport.c
index 012b9bd069952..adfe0d0587010 100644
--- a/fs/smb/client/transport.c
+++ b/fs/smb/client/transport.c
@@ -988,10 +988,10 @@ static void
 cifs_compound_callback(struct mid_q_entry *mid)
 {
 	struct TCP_Server_Info *server = mid->server;
-	struct cifs_credits credits;
-
-	credits.value = server->ops->get_credits(mid);
-	credits.instance = server->reconnect_instance;
+	struct cifs_credits credits = {
+		.value = server->ops->get_credits(mid),
+		.instance = server->reconnect_instance,
+	};
 
 	add_credits(server, &credits, mid->optype);
 
-- 
2.43.0

Re: [PATCH 6.10 083/273] 9p: Fix DIO read through netfs

[Dominique Martinet]

Greg Kroah-Hartman wrote on Tue, Aug 27, 2024 at 04:36:47PM +0200:
> From: Dominique Martinet <asmadeus@codewreck.org>
> 
> [ Upstream commit e3786b29c54cdae3490b07180a54e2461f42144c ]

As much as I'd like to have this in, it breaks cifs so please hold this
patch until at least these two patches also get backported (I didn't
actually test the fix so not sure which is needed, *probably*
either/both):
950b03d0f66 ("netfs: Fix missing iterator reset on retry of short read")
https://lore.kernel.org/r/20240823200819.532106-8-dhowells@redhat.com ("netfs, cifs: Fix handling of short DIO read")

For some reason the former got in master but the later wasn't despite
having been sent together, I might have missed some mails and only the
first might actually be required.. David, Steve please let us know if
just the first is enough.

Either way the 9p patch can wait a couple more weeks; stuck debian CI
(9p) is bad but cifs corruptions are worse.

Thanks,
-- 
Dominique

Re: [PATCH 6.10 083/273] 9p: Fix DIO read through netfs

[Steve French]

We are working through this regression with David this week -
hopefully will have more info in a few days

On Tue, Aug 27, 2024 at 2:59 PM Dominique Martinet
<asmadeus@codewreck.org> wrote:
>
> Greg Kroah-Hartman wrote on Tue, Aug 27, 2024 at 04:36:47PM +0200:
> > From: Dominique Martinet <asmadeus@codewreck.org>
> >
> > [ Upstream commit e3786b29c54cdae3490b07180a54e2461f42144c ]
>
> As much as I'd like to have this in, it breaks cifs so please hold this
> patch until at least these two patches also get backported (I didn't
> actually test the fix so not sure which is needed, *probably*
> either/both):
> 950b03d0f66 ("netfs: Fix missing iterator reset on retry of short read")
> https://lore.kernel.org/r/20240823200819.532106-8-dhowells@redhat.com ("netfs, cifs: Fix handling of short DIO read")
>
> For some reason the former got in master but the later wasn't despite
> having been sent together, I might have missed some mails and only the
> first might actually be required.. David, Steve please let us know if
> just the first is enough.
>
> Either way the 9p patch can wait a couple more weeks; stuck debian CI
> (9p) is bad but cifs corruptions are worse.
>
> Thanks,
> --
> Dominique
>


-- 
Thanks,

Steve

Re: [PATCH 6.10 083/273] 9p: Fix DIO read through netfs

[Greg Kroah-Hartman]

On Wed, Aug 28, 2024 at 04:58:33AM +0900, Dominique Martinet wrote:
> Greg Kroah-Hartman wrote on Tue, Aug 27, 2024 at 04:36:47PM +0200:
> > From: Dominique Martinet <asmadeus@codewreck.org>
> > 
> > [ Upstream commit e3786b29c54cdae3490b07180a54e2461f42144c ]
> 
> As much as I'd like to have this in, it breaks cifs so please hold this
> patch until at least these two patches also get backported (I didn't
> actually test the fix so not sure which is needed, *probably*
> either/both):
> 950b03d0f66 ("netfs: Fix missing iterator reset on retry of short read")
> https://lore.kernel.org/r/20240823200819.532106-8-dhowells@redhat.com ("netfs, cifs: Fix handling of short DIO read")
> 
> For some reason the former got in master but the later wasn't despite
> having been sent together, I might have missed some mails and only the
> first might actually be required.. David, Steve please let us know if
> just the first is enough.
> 
> Either way the 9p patch can wait a couple more weeks; stuck debian CI
> (9p) is bad but cifs corruptions are worse.

Ok, now dropped, thanks!

greg k-h