Commit 3e69426d authored Feb 01, 2020 by Jens Axboe

io_uring: punt even fadvise() WILLNEED to async context



Andres correctly points out that read-ahead can block, if it needs to
read in meta data (or even just through the page cache page allocations).
Play it safe for now and just ensure WILLNEED is also punted to async
context.

While in there, allow the file settings hints from non-blocking
context. They don't need to start/do IO, and we can safely do them
inline.

Fixes: 4840e418 ("io_uring: add IORING_OP_FADVISE")
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 1a417f4e

fs/io_uring.c

+10 −3

Original line number	Diff line number	Diff line
		@@ -2730,9 +2730,16 @@ static int io_fadvise(struct io_kiocb req, struct io_kiocb *nxt,
		struct io_fadvise *fa = &req->fadvise;
		int ret;

		/* DONTNEED may block, others _should_ not */
		if (fa->advice == POSIX_FADV_DONTNEED && force_nonblock)
		if (force_nonblock) {
		switch (fa->advice) {
		case POSIX_FADV_NORMAL:
		case POSIX_FADV_RANDOM:
		case POSIX_FADV_SEQUENTIAL:
		break;
		default:
		return -EAGAIN;
		}
		}

		ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice);
		if (ret < 0)

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