diff options
| author | Goldwyn Rodrigues <rgoldwyn@suse.com> | 2017-06-20 15:05:43 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2017-06-20 16:12:03 +0300 |
| commit | b745fafaf70c0a98a2e1e7ac8cb14542889ceb0e (patch) | |
| tree | 10a7b6f647945c63f17c6d55c346e84d99130ac3 | |
| parent | 9830f4be159b29399d107bffb99e0132bc5aedd4 (diff) | |
| download | linux-b745fafaf70c0a98a2e1e7ac8cb14542889ceb0e.tar.xz | |
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>
| -rw-r--r-- | fs/aio.c | 6 | ||||
| -rw-r--r-- | include/linux/fs.h | 9 | ||||
| -rw-r--r-- | include/uapi/linux/fs.h | 4 |
3 files changed, 18 insertions, 1 deletions
@@ -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"); diff --git a/include/linux/fs.h b/include/linux/fs.h index 0d34f5b5a6b0..4574121f4746 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -143,6 +143,9 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, /* File was opened by fanotify and shouldn't generate fanotify events */ #define FMODE_NONOTIFY ((__force fmode_t)0x4000000) +/* File is capable of returning -EAGAIN if AIO will block */ +#define FMODE_AIO_NOWAIT ((__force fmode_t)0x8000000) + /* * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector * that indicates that they should check the contents of the iovec are @@ -269,6 +272,7 @@ struct writeback_control; #define IOCB_DSYNC (1 << 4) #define IOCB_SYNC (1 << 5) #define IOCB_WRITE (1 << 6) +#define IOCB_NOWAIT (1 << 7) struct kiocb { struct file *ki_filp; @@ -3064,6 +3068,11 @@ static inline int kiocb_set_rw_flags(struct kiocb *ki, int flags) if (unlikely(flags & ~RWF_SUPPORTED)) return -EOPNOTSUPP; + if (flags & RWF_NOWAIT) { + if (!(ki->ki_filp->f_mode & FMODE_AIO_NOWAIT)) + return -EOPNOTSUPP; + ki->ki_flags |= IOCB_NOWAIT; + } if (flags & RWF_HIPRI) ki->ki_flags |= IOCB_HIPRI; if (flags & RWF_DSYNC) diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 937c3e39650a..27d8c36c04af 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -360,7 +360,9 @@ struct fscrypt_key { #define RWF_HIPRI 0x00000001 /* high priority request, poll if possible */ #define RWF_DSYNC 0x00000002 /* per-IO O_DSYNC */ #define RWF_SYNC 0x00000004 /* per-IO O_SYNC */ +#define RWF_NOWAIT 0x00000008 /* per-IO, return -EAGAIN if operation would block */ -#define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC) +#define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC |\ + RWF_NOWAIT) #endif /* _UAPI_LINUX_FS_H */ |