afs: check function return
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.
Changes:
ver #2:
- Need to fix the range_cyclic case also[1].
Fixes: e87b03f5830e ("afs: Prepare for use of THPs")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/20210430155031.3287870-1-trix@redhat.com
Link: https://lore.kernel.org/r/CAB9dFdvHsLsw7CMnB+4cgciWDSqVjuij4mH3TaXnHQB8sz5rHw@mail.gmail.com/ [1]
Link: https://lore.kernel.org/r/162609464716.3133237.10354897554363093252.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/162610727640.3408253.8687445613469681311.stgit@warthog.procyon.org.uk/ # v2
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 3104b62..1ed62e0 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -771,13 +771,19 @@
if (wbc->range_cyclic) {
start = mapping->writeback_index * PAGE_SIZE;
ret = afs_writepages_region(mapping, wbc, start, LLONG_MAX, &next);
- if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
- ret = afs_writepages_region(mapping, wbc, 0, start,
- &next);
- mapping->writeback_index = next / PAGE_SIZE;
+ if (ret == 0) {
+ mapping->writeback_index = next / PAGE_SIZE;
+ if (start > 0 && wbc->nr_to_write > 0) {
+ ret = afs_writepages_region(mapping, wbc, 0,
+ start, &next);
+ if (ret == 0)
+ 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,
