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authorGoldwyn Rodrigues <rgoldwyn@suse.com>2017-06-20 07:05:43 -0500
committerJens Axboe <axboe@kernel.dk>2017-06-20 07:12:03 -0600
commitb745fafaf70c0a98a2e1e7ac8cb14542889ceb0e (patch)
tree10a7b6f647945c63f17c6d55c346e84d99130ac3 /fs/aio.c
parent9830f4be159b29399d107bffb99e0132bc5aedd4 (diff)
downloadlinux-b745fafaf70c0a98a2e1e7ac8cb14542889ceb0e.tar.bz2
fs: Introduce RWF_NOWAIT and FMODE_AIO_NOWAIT
RWF_NOWAIT informs kernel to bail out if an AIO request will block for reasons such as file allocations, or a writeback triggered, or would block while allocating requests while performing direct I/O. RWF_NOWAIT is translated to IOCB_NOWAIT for iocb->ki_flags. FMODE_AIO_NOWAIT is a flag which identifies the file opened is capable of returning -EAGAIN if the AIO call will block. This must be set by supporting filesystems in the ->open() call. Filesystems xfs, btrfs and ext4 would be supported in the following patches. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/aio.c')
-rw-r--r--fs/aio.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 020fa0045e3c..34027b67e2f4 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1592,6 +1592,12 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
goto out_put_req;
}
+ if ((req->common.ki_flags & IOCB_NOWAIT) &&
+ !(req->common.ki_flags & IOCB_DIRECT)) {
+ ret = -EOPNOTSUPP;
+ goto out_put_req;
+ }
+
ret = put_user(KIOCB_KEY, &user_iocb->aio_key);
if (unlikely(ret)) {
pr_debug("EFAULT: aio_key\n");