On Wed, Nov 05, 2014 at 12:53:17AM -0800, Christoph Hellwig wrote: > On Tue, Nov 04, 2014 at 03:38:28PM -0500, Trond Myklebust wrote: > > Hi Ben, > > > > On Tue, Nov 4, 2014 at 10:47 AM, Benjamin Coddington > > <bcodding@xxxxxxxxxx> wrote: > > > I have a customer that would like the client to use DATA_SYNC instead of > > > FILE_SYNC when writing a file with O_DSYNC. It looks like the client will > > > only use FILE_SYNC since: > > > > > > 87ed5eb44ad9338b1617 NFS: Don't use DATA_SYNC writes > > > http://marc.info/?l=git-commits-head&m=131180398113265&w=2 > > > > > > I've been unable to dig up any other discussion on this, so I think it > > > has just been an overlooked point until now. I'm only starting to > > > figure out what would need to change for this, and I thought that while > > > I do that I'd ask the list if anyone thinks that serious implementation > > > issues might emerge if this were attempted. > > > > I'm not aware of any servers that make a real distinction between > > FILE_SYNC and DATA_SYNC. Has anybody done any performance measurements > > to show that it is worth the effort? > > For a fully allocated file the difference between fdatasync and fsync > or O_DSYNC / O_SYNC can make a difference, this is especially notiable > on data base workloads that do lots of small I/O on fully preallocated > files. > > Implementing this difference for the Linux NFS server also seem fairly > trivial, patch attached. Makes sense to me.--b. > > >From 61fee1aacf2f31b6fb1bb90d90f5e625994970f6 Mon Sep 17 00:00:00 2001 > From: Christoph Hellwig <hch@xxxxxx> > Date: Wed, 5 Nov 2014 09:50:35 +0100 > Subject: nfsd: implement DATA_SYNC4 support > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > --- > fs/nfsd/nfs3proc.c | 4 ++-- > fs/nfsd/nfs4proc.c | 7 +++---- > fs/nfsd/nfsproc.c | 7 ++----- > fs/nfsd/vfs.c | 14 +++++++------- > fs/nfsd/vfs.h | 3 ++- > 5 files changed, 16 insertions(+), 19 deletions(-) > > diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c > index 12f2aab..cc9622f 100644 > --- a/fs/nfsd/nfs3proc.c > +++ b/fs/nfsd/nfs3proc.c > @@ -191,12 +191,12 @@ nfsd3_proc_write(struct svc_rqst *rqstp, struct nfsd3_writeargs *argp, > argp->stable? " stable" : ""); > > fh_copy(&resp->fh, &argp->fh); > - resp->committed = argp->stable; > nfserr = nfsd_write(rqstp, &resp->fh, NULL, > argp->offset, > rqstp->rq_vec, argp->vlen, > &cnt, > - &resp->committed); > + argp->stable); > + resp->committed = argp->stable; > resp->count = cnt; > RETURN_STATUS(nfserr); > } > diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c > index c4a2adc..b11fd3b 100644 > --- a/fs/nfsd/nfs4proc.c > +++ b/fs/nfsd/nfs4proc.c > @@ -998,15 +998,14 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, > } > > cnt = write->wr_buflen; > - write->wr_how_written = write->wr_stable_how; > gen_boot_verifier(&write->wr_verifier, SVC_NET(rqstp)); > > nvecs = fill_in_write_vector(rqstp->rq_vec, write); > WARN_ON_ONCE(nvecs > ARRAY_SIZE(rqstp->rq_vec)); > > - status = nfsd_write(rqstp, &cstate->current_fh, filp, > - write->wr_offset, rqstp->rq_vec, nvecs, > - &cnt, &write->wr_how_written); > + status = nfsd_write(rqstp, &cstate->current_fh, filp, write->wr_offset, > + rqstp->rq_vec, nvecs, &cnt, write->wr_stable_how); > + write->wr_how_written = write->wr_stable_how; > if (filp) > fput(filp); > > diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c > index b868073..90caa00 100644 > --- a/fs/nfsd/nfsproc.c > +++ b/fs/nfsd/nfsproc.c > @@ -158,7 +158,6 @@ nfsd_proc_write(struct svc_rqst *rqstp, struct nfsd_writeargs *argp, > struct nfsd_attrstat *resp) > { > __be32 nfserr; > - int stable = 1; > unsigned long cnt = argp->len; > > dprintk("nfsd: WRITE %s %d bytes at %d\n", > @@ -166,10 +165,8 @@ nfsd_proc_write(struct svc_rqst *rqstp, struct nfsd_writeargs *argp, > argp->len, argp->offset); > > nfserr = nfsd_write(rqstp, fh_copy(&resp->fh, &argp->fh), NULL, > - argp->offset, > - rqstp->rq_vec, argp->vlen, > - &cnt, > - &stable); > + argp->offset, rqstp->rq_vec, argp->vlen, > + &cnt, NFS_FILE_SYNC); > return nfsd_return_attrs(nfserr, resp); > } > > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c > index 989129e..2ea8ff6 100644 > --- a/fs/nfsd/vfs.c > +++ b/fs/nfsd/vfs.c > @@ -927,7 +927,7 @@ static int wait_for_concurrent_writes(struct file *file) > static __be32 > nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, > loff_t offset, struct kvec *vec, int vlen, > - unsigned long *cnt, int *stablep) > + unsigned long *cnt, enum nfs3_stable_how stable) > { > struct svc_export *exp; > struct dentry *dentry; > @@ -935,7 +935,6 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, > mm_segment_t oldfs; > __be32 err = 0; > int host_err; > - int stable = *stablep; > int use_wgather; > loff_t pos = offset; > unsigned int pflags = current->flags; > @@ -956,7 +955,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, > use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp); > > if (!EX_ISSYNC(exp)) > - stable = 0; > + stable = NFS_UNSTABLE; > > /* Write the data. */ > oldfs = get_fs(); set_fs(KERNEL_DS); > @@ -972,7 +971,8 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, > if (use_wgather) > host_err = wait_for_concurrent_writes(file); > else > - host_err = vfs_fsync_range(file, offset, offset+*cnt, 0); > + host_err = vfs_fsync_range(file, offset, offset+*cnt, > + stable == NFS_DATA_SYNC); > } > > out_nfserr: > @@ -1051,7 +1051,7 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, > __be32 > nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, > loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt, > - int *stablep) > + enum nfs3_stable_how stable) > { > __be32 err = 0; > > @@ -1061,7 +1061,7 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, > if (err) > goto out; > err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt, > - stablep); > + stable); > } else { > err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file); > if (err) > @@ -1069,7 +1069,7 @@ nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, > > if (cnt) > err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, > - cnt, stablep); > + cnt, stable); > nfsd_close(file); > } > out: > diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h > index c2ff3f1..3cb8e55 100644 > --- a/fs/nfsd/vfs.h > +++ b/fs/nfsd/vfs.h > @@ -81,7 +81,8 @@ __be32 nfsd_readv(struct file *, loff_t, struct kvec *, int, > __be32 nfsd_read(struct svc_rqst *, struct svc_fh *, > loff_t, struct kvec *, int, unsigned long *); > __be32 nfsd_write(struct svc_rqst *, struct svc_fh *,struct file *, > - loff_t, struct kvec *,int, unsigned long *, int *); > + loff_t, struct kvec *,int, unsigned long *, > + enum nfs3_stable_how); > __be32 nfsd_readlink(struct svc_rqst *, struct svc_fh *, > char *, int *); > __be32 nfsd_symlink(struct svc_rqst *, struct svc_fh *, > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
