6b2f3d1f76
While Linux provided an O_SYNC flag basically since day 1, it took until Linux 2.4.0-test12pre2 to actually get it implemented for filesystems, since that day we had generic_osync_around with only minor changes and the great "For now, when the user asks for O_SYNC, we'll actually give O_DSYNC" comment. This patch intends to actually give us real O_SYNC semantics in addition to the O_DSYNC semantics. After Jan's O_SYNC patches which are required before this patch it's actually surprisingly simple, we just need to figure out when to set the datasync flag to vfs_fsync_range and when not. This patch renames the existing O_SYNC flag to O_DSYNC while keeping it's numerical value to keep binary compatibility, and adds a new real O_SYNC flag. To guarantee backwards compatiblity it is defined as expanding to both the O_DSYNC and the new additional binary flag (__O_SYNC) to make sure we are backwards-compatible when compiled against the new headers. This also means that all places that don't care about the differences can just check O_DSYNC and get the right behaviour for O_SYNC, too - only places that actuall care need to check __O_SYNC in addition. Drivers and network filesystems have been updated in a fail safe way to always do the full sync magic if O_DSYNC is set. The few places setting O_SYNC for lower layers are kept that way for now to stay failsafe. We enforce that O_DSYNC is set when __O_SYNC is set early in the open path to make sure we always get these sane options. Note that parisc really screwed up their headers as they already define a O_DSYNC that has always been a no-op. We try to repair it by using it for the new O_DSYNC and redefinining O_SYNC to send both the traditional O_SYNC numerical value _and_ the O_DSYNC one. Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger@sun.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jan Kara <jack@suse.cz>
54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
#ifndef _SPARC_FCNTL_H
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#define _SPARC_FCNTL_H
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#define O_APPEND 0x0008
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#define FASYNC 0x0040 /* fcntl, for BSD compatibility */
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#define O_CREAT 0x0200 /* not fcntl */
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#define O_TRUNC 0x0400 /* not fcntl */
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#define O_EXCL 0x0800 /* not fcntl */
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#define O_DSYNC 0x2000 /* used to be O_SYNC, see below */
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#define O_NONBLOCK 0x4000
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#if defined(__sparc__) && defined(__arch64__)
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#define O_NDELAY 0x0004
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#else
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#define O_NDELAY (0x0004 | O_NONBLOCK)
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#endif
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#define O_NOCTTY 0x8000 /* not fcntl */
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#define O_LARGEFILE 0x40000
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#define O_DIRECT 0x100000 /* direct disk access hint */
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#define O_NOATIME 0x200000
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#define O_CLOEXEC 0x400000
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/*
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* Before Linux 2.6.32 only O_DSYNC semantics were implemented, but using
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* the O_SYNC flag. We continue to use the existing numerical value
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* for O_DSYNC semantics now, but using the correct symbolic name for it.
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* This new value is used to request true Posix O_SYNC semantics. It is
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* defined in this strange way to make sure applications compiled against
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* new headers get at least O_DSYNC semantics on older kernels.
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*
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* This has the nice side-effect that we can simply test for O_DSYNC
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* wherever we do not care if O_DSYNC or O_SYNC is used.
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*
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* Note: __O_SYNC must never be used directly.
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*/
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#define __O_SYNC 0x800000
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#define O_SYNC (__O_SYNC|O_DSYNC)
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#define F_GETOWN 5 /* for sockets. */
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#define F_SETOWN 6 /* for sockets. */
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#define F_GETLK 7
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#define F_SETLK 8
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#define F_SETLKW 9
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/* for posix fcntl() and lockf() */
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#define F_RDLCK 1
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#define F_WRLCK 2
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#define F_UNLCK 3
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#define __ARCH_FLOCK_PAD short __unused;
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#define __ARCH_FLOCK64_PAD short __unused;
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#include <asm-generic/fcntl.h>
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#endif
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