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authorAl Viro <viro@zeniv.linux.org.uk>2023-08-28 18:47:31 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2023-10-27 20:14:11 -0400
commit1939316bf988f3e49a07d9c4dd6f660bf4daa53d (patch)
tree41ba99310df374f9125e15ee15f2a8e08dec6dd0 /io_uring
parent1f36cd05e0081f2c75769a551d584c4ffb2a5660 (diff)
io_uring: kiocb_done() should *not* trust ->ki_pos if ->{read,write}_iter() failed
->ki_pos value is unreliable in such cases. For an obvious example, consider O_DSYNC write - we feed the data to page cache and start IO, then we make sure it's completed. Update of ->ki_pos is dealt with by the first part; failure in the second ends up with negative value returned _and_ ->ki_pos left advanced as if sync had been successful. In the same situation write(2) does not advance the file position at all. Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/rw.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/io_uring/rw.c b/io_uring/rw.c
index c8c822fa7980..08d94fb972f0 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -339,7 +339,7 @@ static int kiocb_done(struct io_kiocb *req, ssize_t ret,
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
unsigned final_ret = io_fixup_rw_res(req, ret);
- if (req->flags & REQ_F_CUR_POS)
+ if (ret >= 0 && req->flags & REQ_F_CUR_POS)
req->file->f_pos = rw->kiocb.ki_pos;
if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) {
if (!__io_complete_rw_common(req, ret)) {