Merge: netfs: Fix unbuffered write error handling

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/1371

- Fix unbuffered write error handling in netfslib

JIRA: https://issues.redhat.com/browse/RHEL-104442

Signed-off-by: Paulo Alcantara <paalcant@redhat.com>

Approved-by: Scott Mayhew <smayhew@redhat.com>
Approved-by: David Howells <dhowells@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>
Approved-by: Jay Shin <jaeshin@redhat.com>

Merged-by: Scott Weaver <scweaver@redhat.com>

Author: swvrrh

fs/netfs/read_collect.c

@@ -281,8 +281,10 @@ static void netfs_collect_read_results(struct netfs_io_request *rreq)
 		} else if (test_bit(NETFS_RREQ_SHORT_TRANSFER, &rreq->flags)) {
 			notes |= MADE_PROGRESS;
 		} else {
-			if (!stream->failed)
+			if (!stream->failed) {
 				stream->transferred += transferred;
+				stream->transferred_valid = true;
+			}
 			if (front->transferred < front->len)
 				set_bit(NETFS_RREQ_SHORT_TRANSFER, &rreq->flags);
 			notes |= MADE_PROGRESS;

fs/netfs/write_collect.c

@@ -254,6 +254,7 @@ static void netfs_collect_write_results(struct netfs_io_request *wreq)
 			if (front->start + front->transferred > stream->collected_to) {
 				stream->collected_to = front->start + front->transferred;
 				stream->transferred = stream->collected_to - wreq->start;
+				stream->transferred_valid = true;
 				notes |= MADE_PROGRESS;
 			}
 			if (test_bit(NETFS_SREQ_FAILED, &front->flags)) {
@@ -356,6 +357,7 @@ bool netfs_write_collection(struct netfs_io_request *wreq)
 {
 	struct netfs_inode *ictx = netfs_inode(wreq->inode);
 	size_t transferred;
+	bool transferred_valid = false;
 	int s;
 
 	_enter("R=%x", wreq->debug_id);
@@ -376,12 +378,16 @@ bool netfs_write_collection(struct netfs_io_request *wreq)
 			continue;
 		if (!list_empty(&stream->subrequests))
 			return false;
-		if (stream->transferred < transferred)
+		if (stream->transferred_valid &&
+		    stream->transferred < transferred) {
 			transferred = stream->transferred;
+			transferred_valid = true;
+		}
 	}
 
 	/* Okay, declare that all I/O is complete. */
-	wreq->transferred = transferred;
+	if (transferred_valid)
+		wreq->transferred = transferred;
 	trace_netfs_rreq(wreq, netfs_rreq_trace_write_done);
 
 	if (wreq->io_streams[1].active &&

fs/netfs/write_issue.c

@@ -118,12 +118,12 @@ struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
 	wreq->io_streams[0].prepare_write	= ictx->ops->prepare_write;
 	wreq->io_streams[0].issue_write		= ictx->ops->issue_write;
 	wreq->io_streams[0].collected_to	= start;
-	wreq->io_streams[0].transferred		= LONG_MAX;
+	wreq->io_streams[0].transferred		= 0;
 
 	wreq->io_streams[1].stream_nr		= 1;
 	wreq->io_streams[1].source		= NETFS_WRITE_TO_CACHE;
 	wreq->io_streams[1].collected_to	= start;
-	wreq->io_streams[1].transferred		= LONG_MAX;
+	wreq->io_streams[1].transferred		= 0;
 	if (fscache_resources_valid(&wreq->cache_resources)) {
 		wreq->io_streams[1].avail	= true;
 		wreq->io_streams[1].active	= true;

fs/splice.c

@@ -744,6 +744,9 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 		sd.pos = kiocb.ki_pos;
 		if (ret <= 0)
 			break;
+		WARN_ONCE(ret > sd.total_len - left,
+			  "Splice Exceeded! ret=%zd tot=%zu left=%zu\n",
+			  ret, sd.total_len, left);
 
 		sd.num_spliced += ret;
 		sd.total_len -= ret;

include/linux/netfs.h

@@ -150,6 +150,7 @@ struct netfs_io_stream {
 	bool			active;		/* T if stream is active */
 	bool			need_retry;	/* T if this stream needs retrying */
 	bool			failed;		/* T if this stream failed */
+	bool			transferred_valid; /* T is ->transferred is valid */
 };
 
 /*