diff options
| author | Raghavendra G <rgowdapp@redhat.com> | 2017-12-22 12:02:09 +0530 |
|---|---|---|
| committer | Jeff Darcy <jeff@pl.atyp.us> | 2017-12-22 17:44:57 +0000 |
| commit | 0bc22bef7f3c24663aadfb3548b348aa121e3047 (patch) | |
| tree | cd3d8bb534e3397f32563834b111cf75079e0559 /xlators | |
| parent | f4734305783ce3aa10721bf2731923f6aa39252b (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>
Diffstat (limited to 'xlators')
| -rw-r--r-- | xlators/performance/write-behind/src/write-behind.c | 5 |
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; } |