[PATCH] afs: check function return

[trix at redhat.com]

From: Tom Rix <trix at redhat.com>

Static analysis reports this problem

write.c:773:29: warning: Assigned value is garbage or undefined
  mapping->writeback_index = next;
                           ^ ~~~~
The call to afs_writepages_region() can return without setting
next.  So check the function return before using next.

Fixes: e87b03f5830e ("afs: Prepare for use of THPs")
Signed-off-by: Tom Rix <trix at redhat.com>
---
 fs/afs/write.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/afs/write.c b/fs/afs/write.c
index dc66ff15dd16..cabacb6b59da 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -769,7 +769,7 @@ int afs_writepages(struct address_space *mapping,
 		mapping->writeback_index = next / PAGE_SIZE;
 	} else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
 		ret = afs_writepages_region(mapping, wbc, 0, LLONG_MAX, &next);
-		if (wbc->nr_to_write > 0)
+		if (wbc->nr_to_write > 0 && ret == 0)
 			mapping->writeback_index = next;
 	} else {
 		ret = afs_writepages_region(mapping, wbc,
-- 
2.26.3