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Commit e1fc742e authored by Jürg Billeter's avatar Jürg Billeter Committed by Al Viro
Browse files

fs: add RWF_APPEND 



This is the per-I/O equivalent of O_APPEND to support atomic append
operations on any open file.

If a file is opened with O_APPEND, pwrite() ignores the offset and
always appends data to the end of the file. RWF_APPEND enables atomic
append and pwrite() with offset on a single file descriptor.

Signed-off-by: default avatarJürg Billeter <j@bitron.ch>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c981f254

include/linux/fs.h

+2 −0
Original line number Diff line number Diff line
@@ -3224,6 +3224,8 @@ static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags) 
		ki->ki_flags |= IOCB_DSYNC;

	if (flags & RWF_SYNC)

		ki->ki_flags |= (IOCB_DSYNC | IOCB_SYNC);

	if (flags & RWF_APPEND)

		ki->ki_flags |= IOCB_APPEND;

	return 0;

}

include/uapi/linux/fs.h

+5 −1
Original line number Diff line number Diff line
@@ -377,7 +377,11 @@ typedef int __bitwise __kernel_rwf_t; 
/* per-IO, return -EAGAIN if operation would block */

#define RWF_NOWAIT	((__force __kernel_rwf_t)0x00000008)



/* per-IO O_APPEND */

#define RWF_APPEND	((__force __kernel_rwf_t)0x00000010)



/* mask of flags supported by the kernel */

#define RWF_SUPPORTED	(RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT)

#define RWF_SUPPORTED	(RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\

			 RWF_APPEND)



#endif /* _UAPI_LINUX_FS_H */