mirror of https://github.com/torvalds/linux.git
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> |
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| .. | ||
| bitops | ||
| 4level-fixup.h | ||
| Kbuild | ||
| Kbuild.asm | ||
| atomic-long.h | ||
| atomic.h | ||
| atomic64.h | ||
| audit_change_attr.h | ||
| audit_dir_write.h | ||
| audit_read.h | ||
| audit_signal.h | ||
| audit_write.h | ||
| auxvec.h | ||
| bitops.h | ||
| bitsperlong.h | ||
| bug.h | ||
| bugs.h | ||
| cache.h | ||
| cacheflush.h | ||
| checksum.h | ||
| cmpxchg-local.h | ||
| cmpxchg.h | ||
| cputime.h | ||
| current.h | ||
| delay.h | ||
| device.h | ||
| div64.h | ||
| dma-coherent.h | ||
| dma-mapping-broken.h | ||
| dma-mapping-common.h | ||
| dma.h | ||
| emergency-restart.h | ||
| errno-base.h | ||
| errno.h | ||
| fb.h | ||
| fcntl.h | ||
| futex.h | ||
| getorder.h | ||
| gpio.h | ||
| hardirq.h | ||
| hw_irq.h | ||
| ide_iops.h | ||
| int-l64.h | ||
| int-ll64.h | ||
| io.h | ||
| ioctl.h | ||
| ioctls.h | ||
| iomap.h | ||
| ipcbuf.h | ||
| irq.h | ||
| irq_regs.h | ||
| irqflags.h | ||
| kdebug.h | ||
| kmap_types.h | ||
| libata-portmap.h | ||
| linkage.h | ||
| local.h | ||
| memory_model.h | ||
| mm_hooks.h | ||
| mman-common.h | ||
| mman.h | ||
| mmu.h | ||
| mmu_context.h | ||
| module.h | ||
| msgbuf.h | ||
| mutex-dec.h | ||
| mutex-null.h | ||
| mutex-xchg.h | ||
| mutex.h | ||
| page.h | ||
| param.h | ||
| parport.h | ||
| pci-dma-compat.h | ||
| pci.h | ||
| percpu.h | ||
| pgalloc.h | ||
| pgtable-nopmd.h | ||
| pgtable-nopud.h | ||
| pgtable.h | ||
| poll.h | ||
| posix_types.h | ||
| resource.h | ||
| rtc.h | ||
| scatterlist.h | ||
| sections.h | ||
| segment.h | ||
| sembuf.h | ||
| serial.h | ||
| setup.h | ||
| shmbuf.h | ||
| shmparam.h | ||
| siginfo.h | ||
| signal-defs.h | ||
| signal.h | ||
| socket.h | ||
| sockios.h | ||
| spinlock.h | ||
| stat.h | ||
| statfs.h | ||
| string.h | ||
| swab.h | ||
| syscall.h | ||
| syscalls.h | ||
| system.h | ||
| termbits.h | ||
| termios-base.h | ||
| termios.h | ||
| timex.h | ||
| tlb.h | ||
| tlbflush.h | ||
| topology.h | ||
| types.h | ||
| uaccess-unaligned.h | ||
| uaccess.h | ||
| ucontext.h | ||
| unaligned.h | ||
| unistd.h | ||
| user.h | ||
| vga.h | ||
| vmlinux.lds.h | ||
| xor.h | ||