NFS: direct.c: Fix memory leak of dreq when nfs_get_lock_context fails

Commit Message

Misono Tomohiro Aug. 28, 2019, 8:01 a.m. UTC

When dreq is allocated by nfs_direct_req_alloc(), dreq->kref is
initialized to 2. Therefore we need to call nfs_direct_req_release()
twice to release the allocated dreq. Usually it is called in
nfs_file_direct_{read, write}() and nfs_direct_complete().

However, current code only calls nfs_direct_req_relese() once if
nfs_get_lock_context() fails in nfs_file_direct_{read, write}().
So, that case would result in memory leak.

Fix this by adding the missing call.

Signed-off-by: Misono Tomohiro <[e-mail]>
---
 Hello,

 I noticed this when reading the code.

 Thanks.

 fs/nfs/direct.c | 2 ++
 1 file changed, 2 insertions(+)

Patch

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 0cb442406168..18eff685e5fe 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -586,6 +586,7 @@  ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter)
 	l_ctx = nfs_get_lock_context(dreq->ctx);
 	if (IS_ERR(l_ctx)) {
 		result = PTR_ERR(l_ctx);
+		nfs_direct_req_release(dreq);
 		goto out_release;
 	}
 	dreq->l_ctx = l_ctx;
@@ -1014,6 +1015,7 @@  ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
 	l_ctx = nfs_get_lock_context(dreq->ctx);
 	if (IS_ERR(l_ctx)) {
 		result = PTR_ERR(l_ctx);
+		nfs_direct_req_release(dreq);
 		goto out_release;
 	}
 	dreq->l_ctx = l_ctx;