There is no real problem merging ioends that go beyond i_size into an
ioend that doesn't. We just need to move the append transaction to the
base ioend. Also use the opportunity to use a real error code instead
of the magic 1 to cancel the transactions, and write a comment
explaining the scheme.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/xfs/xfs_aops.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 8b3070a40245..4ef8343c3759 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -314,11 +314,28 @@ xfs_ioend_can_merge(
return false;
if (ioend->io_offset + ioend->io_size != next->io_offset)
return false;
- if (xfs_ioend_is_append(ioend) != xfs_ioend_is_append(next))
- return false;
return true;
}
+/*
+ * If the to be merged ioend has a preallocated transaction for file
+ * size updates we need to ensure the ioend it is merged into also
+ * has one. If it already has one we can simply cancel the transaction
+ * as it is guaranteed to be clean.
+ */
+static void
+xfs_ioend_merge_append_transactions(
+ struct xfs_ioend *ioend,
+ struct xfs_ioend *next)
+{
+ if (!ioend->io_append_trans) {
+ ioend->io_append_trans = next->io_append_trans;
+ next->io_append_trans = NULL;
+ } else {
+ xfs_setfilesize_ioend(next, -ECANCELED);
+ }
+}
+
/* Try to merge adjacent completions. */
STATIC void
xfs_ioend_try_merge(
@@ -327,7 +344,6 @@ xfs_ioend_try_merge(
{
struct xfs_ioend *next_ioend;
int ioend_error;
- int error;
if (list_empty(more_ioends))
return;
@@ -341,10 +357,8 @@ xfs_ioend_try_merge(
break;
list_move_tail(&next_ioend->io_list, &ioend->io_list);
ioend->io_size += next_ioend->io_size;
- if (ioend->io_append_trans) {
- error = xfs_setfilesize_ioend(next_ioend, 1);
- ASSERT(error == 1);
- }
+ if (next_ioend->io_append_trans)
+ xfs_ioend_merge_append_transactions(ioend, next_ioend);
}
}
--
2.20.1
