From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Mon, 4 Sep 2023 12:34:39 -0400
Subject: [PATCH] NFS: More O_DIRECT accounting fixes for error paths
Git-commit: 8982f7aff39fb526aba4441fff2525fcedd5e1a3
Patch-mainline: v6.6
References: git-fixes

If we hit a fatal error when retransmitting, we do need to record the
removal of the request from the count of written bytes.

Fixes: 031d73ed768a ("NFS: Fix O_DIRECT accounting of number of bytes read/written")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfs/direct.c |   47 +++++++++++++++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 16 deletions(-)

--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -135,12 +135,10 @@ nfs_direct_handle_truncated(struct nfs_d
 		dreq->max_count = dreq_len;
 		if (dreq->count > dreq_len)
 			dreq->count = dreq_len;
-
-		if (test_bit(NFS_IOHDR_ERROR, &hdr->flags))
-			dreq->error = hdr->error;
-		else /* Clear outstanding error if this is EOF */
-			dreq->error = 0;
 	}
+
+	if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && !dreq->error)
+		dreq->error = hdr->error;
 	if (mirror->count > dreq_len)
 		mirror->count = dreq_len;
 }
@@ -167,6 +165,18 @@ nfs_direct_count_bytes(struct nfs_direct
 		dreq->count = dreq_len;
 }
 
+static void nfs_direct_truncate_request(struct nfs_direct_req *dreq,
+					struct nfs_page *req)
+{
+	loff_t offs = req_offset(req);
+	size_t req_start = (size_t)(offs - dreq->io_start);
+
+	if (req_start < dreq->max_count)
+		dreq->max_count = req_start;
+	if (req_start < dreq->count)
+		dreq->count = req_start;
+}
+
 /**
  * nfs_direct_IO - NFS address space operation for direct I/O
  * @iocb: target I/O control block
@@ -562,10 +572,6 @@ static void nfs_direct_write_reschedule(
 	nfs_init_cinfo_from_dreq(&cinfo, dreq);
 	nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo);
 
-	dreq->count = 0;
-	dreq->max_count = 0;
-	list_for_each_entry(req, &reqs, wb_list)
-		dreq->max_count += req->wb_bytes;
 	nfs_clear_pnfs_ds_commit_verifiers(&dreq->ds_cinfo);
 	for (i = 0; i < dreq->mirror_count; i++)
 		dreq->mirrors[i].count = 0;
@@ -605,10 +611,14 @@ out_failed:
 		req = nfs_list_entry(reqs.next);
 		nfs_list_remove_request(req);
 		nfs_unlock_and_release_request(req);
-		if (desc.pg_error == -EAGAIN)
+		if (desc.pg_error == -EAGAIN) {
 			nfs_mark_request_commit(req, NULL, &cinfo, 0);
-		else
+		} else {
+			spin_lock(&dreq->lock);
+			nfs_direct_truncate_request(dreq, req);
+			spin_unlock(&dreq->lock);
 			nfs_release_request(req);
+		}
 	}
 
 	if (put_dreq(dreq))
@@ -626,8 +636,6 @@ static void nfs_direct_commit_complete(s
 	if (status < 0) {
 		/* Errors in commit are fatal */
 		dreq->error = status;
-		dreq->max_count = 0;
-		dreq->count = 0;
 		dreq->flags = NFS_ODIRECT_DONE;
 	} else if (dreq->flags == NFS_ODIRECT_DONE)
 		status = dreq->error;
@@ -637,10 +645,15 @@ static void nfs_direct_commit_complete(s
 	while (!list_empty(&data->pages)) {
 		req = nfs_list_entry(data->pages.next);
 		nfs_list_remove_request(req);
-		if (status >= 0 && !nfs_write_match_verf(verf, req)) {
+		if (status < 0) {
+			spin_lock(&dreq->lock);
+			nfs_direct_truncate_request(dreq, req);
+			spin_unlock(&dreq->lock);
+			nfs_release_request(req);
+		} else if (!nfs_write_match_verf(verf, req)) {
 			dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
 			nfs_mark_request_commit(req, NULL, &cinfo, 0);
-		} else /* Error or match */
+		} else
 			nfs_release_request(req);
 		nfs_unlock_and_release_request(req);
 	}
@@ -691,6 +704,7 @@ static void nfs_direct_write_clear_reqs(
 	while (!list_empty(&reqs)) {
 		req = nfs_list_entry(reqs.next);
 		nfs_list_remove_request(req);
+		nfs_direct_truncate_request(dreq, req);
 		nfs_release_request(req);
 		nfs_unlock_and_release_request(req);
 	}
@@ -737,7 +751,8 @@ static void nfs_direct_write_completion(
 	}
 
 	nfs_direct_count_bytes(dreq, hdr);
-	if (test_bit(NFS_IOHDR_UNSTABLE_WRITES, &hdr->flags)) {
+	if (test_bit(NFS_IOHDR_UNSTABLE_WRITES, &hdr->flags) &&
+	    !test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
 		switch (dreq->flags) {
 		case 0:
 			dreq->flags = NFS_ODIRECT_DO_COMMIT;