mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-15 23:25:07 +00:00
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> |
||
|---|---|---|
| .. | ||
| .gitignore | ||
| 8250-platform.c | ||
| asm-offsets.c | ||
| binfmt_elfn32.c | ||
| binfmt_elfo32.c | ||
| branch.c | ||
| cevt-bcm1480.c | ||
| cevt-ds1287.c | ||
| cevt-gt641xx.c | ||
| cevt-r4k.c | ||
| cevt-sb1250.c | ||
| cevt-smtc.c | ||
| cevt-txx9.c | ||
| cpu-bugs64.c | ||
| cpu-probe.c | ||
| csrc-bcm1480.c | ||
| csrc-ioasic.c | ||
| csrc-r4k.c | ||
| csrc-sb1250.c | ||
| early_printk.c | ||
| entry.S | ||
| genex.S | ||
| gpio_txx9.c | ||
| head.S | ||
| i8253.c | ||
| i8259.c | ||
| init_task.c | ||
| irq-gic.c | ||
| irq-gt641xx.c | ||
| irq-msc01.c | ||
| irq-rm7000.c | ||
| irq-rm9000.c | ||
| irq.c | ||
| irq_cpu.c | ||
| irq_txx9.c | ||
| kgdb.c | ||
| kspd.c | ||
| linux32.c | ||
| machine_kexec.c | ||
| Makefile | ||
| mips-mt-fpaff.c | ||
| mips-mt.c | ||
| mips_ksyms.c | ||
| module.c | ||
| octeon_switch.S | ||
| proc.c | ||
| process.c | ||
| ptrace.c | ||
| ptrace32.c | ||
| r4k_fpu.S | ||
| r4k_switch.S | ||
| r2300_fpu.S | ||
| r2300_switch.S | ||
| r6000_fpu.S | ||
| relocate_kernel.S | ||
| reset.c | ||
| rtlx.c | ||
| scall32-o32.S | ||
| scall64-64.S | ||
| scall64-n32.S | ||
| scall64-o32.S | ||
| setup.c | ||
| signal-common.h | ||
| signal.c | ||
| signal32.c | ||
| signal_n32.c | ||
| smp-cmp.c | ||
| smp-mt.c | ||
| smp-up.c | ||
| smp.c | ||
| smtc-asm.S | ||
| smtc-proc.c | ||
| smtc.c | ||
| spram.c | ||
| stacktrace.c | ||
| sync-r4k.c | ||
| syscall.c | ||
| time.c | ||
| topology.c | ||
| traps.c | ||
| unaligned.c | ||
| vmlinux.lds.S | ||
| vpe.c | ||
| watch.c | ||