linux/arch/mips/mm
Christoph Hellwig 6b2f3d1f76 vfs: Implement proper O_SYNC semantics
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>
2009-12-10 15:02:50 +01:00
..
c-octeon.c cpumask: use mm_cpumask() wrapper: mips 2009-09-24 09:34:51 +09:30
c-r3k.c MIPS: Build fix - include <linux/smp.h> into all smp_processor_id() users. 2009-06-24 18:34:39 +01:00
c-r4k.c MIPS: Build fix - include <linux/smp.h> into all smp_processor_id() users. 2009-06-24 18:34:39 +01:00
c-tx39.c MIPS: Build fix - include <linux/smp.h> into all smp_processor_id() users. 2009-06-24 18:34:39 +01:00
cache.c vfs: Implement proper O_SYNC semantics 2009-12-10 15:02:50 +01:00
cerr-sb1.c [MIPS] Sibyte: Replace use of removed IO_SPACE_BASE with IOADDR. 2007-11-15 23:21:49 +00:00
cex-gen.S
cex-oct.S MIPS: Add Cavium OCTEON processor support files to arch/mips/cavium-octeon. 2009-01-11 09:57:21 +00:00
cex-sb1.S [MIPS] Fix loads of section missmatches 2008-03-12 14:14:41 +00:00
dma-default.c MIPS: Add DMA declare coherent memory support 2009-11-13 18:10:37 +01:00
extable.c MIPS: Eleminate filenames from comments 2009-08-03 17:52:40 +01:00
fault.c MIPS: Don't corrupt page tables on vmalloc fault. 2009-09-17 20:07:52 +02:00
highmem.c MIPS: Build fix - include <linux/smp.h> into all smp_processor_id() users. 2009-06-24 18:34:39 +01:00
hugetlbpage.c headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
init.c MIPS: Fix machine check exception in kmap_coherent() 2009-11-02 12:00:04 +01:00
ioremap.c MIPS: Use BUG_ON() where possible. 2009-03-30 14:49:44 +02:00
Makefile MIPS: Add support files for hugetlbfs. 2009-06-17 11:06:30 +01:00
page.c MIPS: Build fix - include <linux/smp.h> into all smp_processor_id() users. 2009-06-24 18:34:39 +01:00
pgtable-32.c
pgtable-64.c MIPS: Shrink the size of tlb handler 2009-09-17 20:07:51 +02:00
sc-ip22.c MIPS: IP22: Make indy_sc_ops variable static 2008-11-20 19:42:33 +00:00
sc-mips.c MIPS: MIPSxx SC: Avoid destructive invalidation on partial L2 cachelines. 2009-09-30 21:47:00 +02:00
sc-r5k.c [MIPS] Fix loads of section missmatches 2008-03-12 14:14:41 +00:00
sc-rm7k.c MIPS: IP32: Two symbols can become static 2009-05-14 13:50:24 +01:00
tlb-r3k.c MIPS: Build fix - include <linux/smp.h> into all smp_processor_id() users. 2009-06-24 18:34:39 +01:00
tlb-r4k.c MIPS: Remove useless zero initializations. 2009-09-17 20:07:51 +02:00
tlb-r8k.c MIPS: Build fix - include <linux/smp.h> into all smp_processor_id() users. 2009-06-24 18:34:39 +01:00
tlbex-fault.S
tlbex.c MIPS: BCM63xx: Add Broadcom 63xx CPU definitions. 2009-09-17 20:07:52 +02:00
uasm.c [MIPS] Make two functions static 2008-07-15 18:44:29 +01:00
uasm.h [MIPS] Make two functions static 2008-07-15 18:44:29 +01:00