Merge tag 'io_uring-6.12-20241101' of git://git.kernel.dk/linux
Pull io_uring fix from Jens Axboe:
- Fix not honoring IOCB_NOWAIT for starting buffered writes in terms of
calling sb_start_write(), leading to a deadlock if someone is
attempting to freeze the file system with writes in progress, as each
side will end up waiting for the other to make progress.
* tag 'io_uring-6.12-20241101' of git://git.kernel.dk/linux:
io_uring/rw: fix missing NOWAIT check for O_DIRECT start write
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 354c4e1..155938f 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -1014,6 +1014,25 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
return IOU_OK;
}
+static bool io_kiocb_start_write(struct io_kiocb *req, struct kiocb *kiocb)
+{
+ struct inode *inode;
+ bool ret;
+
+ if (!(req->flags & REQ_F_ISREG))
+ return true;
+ if (!(kiocb->ki_flags & IOCB_NOWAIT)) {
+ kiocb_start_write(kiocb);
+ return true;
+ }
+
+ inode = file_inode(kiocb->ki_filp);
+ ret = sb_start_write_trylock(inode->i_sb);
+ if (ret)
+ __sb_writers_release(inode->i_sb, SB_FREEZE_WRITE);
+ return ret;
+}
+
int io_write(struct io_kiocb *req, unsigned int issue_flags)
{
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
@@ -1051,8 +1070,8 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags)
if (unlikely(ret))
return ret;
- if (req->flags & REQ_F_ISREG)
- kiocb_start_write(kiocb);
+ if (unlikely(!io_kiocb_start_write(req, kiocb)))
+ return -EAGAIN;
kiocb->ki_flags |= IOCB_WRITE;
if (likely(req->file->f_op->write_iter))
