[PATCH 5.16 110/285] ceph: fix memory leak in ceph_readdir when note_last_dentry returns error

Greg Kroah-Hartman
2022-04-12T07:45:57Z

From: Xiubo Li <xiubli@redhat.com>

[ Upstream commit f639d9867eea647005dc824e0e24f39ffc50d4e4 ]

Reset the last_readdir at the same time, and add a comment explaining
why we don't free last_readdir when dir_emit returns false.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ceph/dir.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 133dbd9338e7..d91fa53e12b3 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -478,8 +478,11 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
2 : (fpos_off(rde->offset) + 1);
err = note_last_dentry(dfi, rde->name, rde->name_len,
next_offset);
- if (err)
+ if (err) {
+ ceph_mdsc_put_request(dfi->last_readdir);
+ dfi->last_readdir = NULL;
return err;
+ }
} else if (req->r_reply_info.dir_end) {
dfi->next_offset = 2;
/* keep last name */
@@ -520,6 +523,12 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
if (!dir_emit(ctx, rde->name, rde->name_len,
ceph_present_ino(inode->i_sb, le64_to_cpu(rde->inode.in->ino)),
le32_to_cpu(rde->inode.in->mode) >> 12)) {
+ /*
+ * NOTE: Here no need to put the 'dfi->last_readdir',
+ * because when dir_emit stops us it's most likely
+ * doesn't have enough memory, etc. So for next readdir
+ * it will continue.
+ */
dout("filldir stopping us...\n");
return 0;
}
--
2.35.1