summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorRaghavendra G <rgowdapp@redhat.com>2017-12-22 12:02:09 +0530
committerJeff Darcy <jeff@pl.atyp.us>2017-12-22 17:44:57 +0000
commit0bc22bef7f3c24663aadfb3548b348aa121e3047 (patch)
treecd3d8bb534e3397f32563834b111cf75079e0559
parentf4734305783ce3aa10721bf2731923f6aa39252b (diff)
performance/write-behind: fix bug while handling short writes
The variabled "fulfilled" in wb_fulfill_short_write is not reset to 0 while handling every member of the list. This has some interesting consequences: * If we break from the loop while processing last member of the list head->winds, req is reset to head as the list is a circular one. However, head is already fulfilled and can potentially be freed. So, we end up adding a freed request to wb_inode->todo list. This is the RCA for the crash tracked by the bug associated with this patch (Note that we saw "holder" which is freed in todo list). * If we break from the loop while processing any of the last but one member of the list head->winds, req is set to next member in the list, skipping the current request, even though it is not entirely synced. This can lead to data corruption. The fix is very simple and we've to change the code to make sure "fulfilled" reflects whether the current request is fulfilled or not and it doesn't carry history of previous requests in the list. Change-Id: Ia3d6988175a51c9e08efdb521a7b7938b01f93c8 BUG: 1528558 Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
-rw-r--r--xlators/performance/write-behind/src/write-behind.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/xlators/performance/write-behind/src/write-behind.c b/xlators/performance/write-behind/src/write-behind.c
index 67dd1f51ea1..2a2520147fe 100644
--- a/xlators/performance/write-behind/src/write-behind.c
+++ b/xlators/performance/write-behind/src/write-behind.c
@@ -964,6 +964,7 @@ __wb_fulfill_short_write (wb_request_t *req, int size, gf_boolean_t *fulfilled)
} else {
accounted_size = size;
__wb_modify_write_request (req, size);
+ *fulfilled = 0;
}
out:
@@ -1005,7 +1006,7 @@ wb_fulfill_short_write (wb_request_t *head, int size)
size -= accounted_size;
if (size == 0) {
- if (fulfilled)
+ if (fulfilled && (next != head))
req = next;
goto done;
@@ -1017,7 +1018,7 @@ wb_fulfill_short_write (wb_request_t *head, int size)
size -= accounted_size;
if (size == 0) {
- if (fulfilled)
+ if (fulfilled && (next != head))
req = next;
break;
}