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authorGoldwyn Rodrigues <rgoldwyn@suse.com>2017-06-20 15:05:43 +0300
committerJens Axboe <axboe@kernel.dk>2017-06-20 16:12:03 +0300
commitb745fafaf70c0a98a2e1e7ac8cb14542889ceb0e (patch)
tree10a7b6f647945c63f17c6d55c346e84d99130ac3 /include/uapi
parent9830f4be159b29399d107bffb99e0132bc5aedd4 (diff)
downloadlinux-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>
Diffstat (limited to 'include/uapi')
-rw-r--r--include/uapi/linux/fs.h4
1 files changed, 3 insertions, 1 deletions
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 */