[PATCH 5.4 152/232] io_uring: honor original task RLIMIT_FSIZE

From: Greg Kroah-Hartman
Date: Thu Apr 16 2020 - 11:18:31 EST


From: Jens Axboe <axboe@xxxxxxxxx>

commit 4ed734b0d0913e566a9d871e15d24eb240f269f7 upstream.

With the previous fixes for number of files open checking, I added some
debug code to see if we had other spots where we're checking rlimit()
against the async io-wq workers. The only one I found was file size
checking, which we should also honor.

During write and fallocate prep, store the max file size and override
that for the current ask if we're in io-wq worker context.

Cc: stable@xxxxxxxxxxxxxxx # 5.1+
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>


---
fs/io_uring.c | 11 +++++++++++
1 file changed, 11 insertions(+)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -331,6 +331,7 @@ struct io_kiocb {
#define REQ_F_ISREG 2048 /* regular file */
#define REQ_F_MUST_PUNT 4096 /* must be punted even for NONBLOCK */
#define REQ_F_TIMEOUT_NOSEQ 8192 /* no timeout sequence */
+ unsigned long fsize;
u64 user_data;
u32 result;
u32 sequence;
@@ -1085,6 +1086,9 @@ static int io_prep_rw(struct io_kiocb *r
if (S_ISREG(file_inode(req->file)->i_mode))
req->flags |= REQ_F_ISREG;

+ if (force_nonblock)
+ req->fsize = rlimit(RLIMIT_FSIZE);
+
/*
* If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
* we know to async punt it even if it was opened O_NONBLOCK
@@ -1504,10 +1508,17 @@ static int io_write(struct io_kiocb *req
}
kiocb->ki_flags |= IOCB_WRITE;

+ if (!force_nonblock)
+ current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize;
+
if (file->f_op->write_iter)
ret2 = call_write_iter(file, kiocb, &iter);
else
ret2 = loop_rw_iter(WRITE, file, kiocb, &iter);
+
+ if (!force_nonblock)
+ current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
+
if (!force_nonblock || ret2 != -EAGAIN) {
io_rw_done(kiocb, ret2);
} else {