rpms/kernel/F-11 linux-2.6-nfsd-report-short-writes.patch, NONE, 1.1 kernel.spec, 1.1642, 1.1643

[Chuck Ebbert]

Author: cebbert

Update of /cvs/pkgs/rpms/kernel/F-11
In directory cvs1.fedora.phx.redhat.com:/tmp/cvs-serv10239

Modified Files:
	kernel.spec 
Added Files:
	linux-2.6-nfsd-report-short-writes.patch 
Log Message:
Fix reporting of short writes to the NFS client (#493500)

linux-2.6-nfsd-report-short-writes.patch:

--- NEW FILE linux-2.6-nfsd-report-short-writes.patch ---
From: David Shaw <dshaw at jabberwocky.com>
Date: Fri, 6 Mar 2009 01:16:14 +0000 (-0500)
Subject: Short write in nfsd becomes a full write to the client
X-Git-Tag: v2.6.30-rc1~183^2~52
X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=31dec2538e45e9fff2007ea1f4c6bae9f78db724

Short write in nfsd becomes a full write to the client

If a filesystem being written to via NFS returns a short write count
(as opposed to an error) to nfsd, nfsd treats that as a success for
the entire write, rather than the short count that actually succeeded.

For example, given a 8192 byte write, if the underlying filesystem
only writes 4096 bytes, nfsd will ack back to the nfs client that all
8192 bytes were written.  The nfs client does have retry logic for
short writes, but this is never called as the client is told the
complete write succeeded.

There are probably other ways it could happen, but in my case it
happened with a fuse (filesystem in userspace) filesystem which can
rather easily have a partial write.

Here is a patch to properly return the short write count to the
client.

Signed-off-by: David Shaw <dshaw at jabberwocky.com>
Signed-off-by: J. Bruce Fields <bfields at citi.umich.edu>
---

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 579ce8c..7c9fe83 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -203,6 +203,7 @@ nfsd3_proc_write(struct svc_rqst *rqstp, struct nfsd3_writeargs *argp,
 					 struct nfsd3_writeres  *resp)
 {
 	__be32	nfserr;
+	unsigned long cnt = argp->len;
 
 	dprintk("nfsd: WRITE(3)    %s %d bytes at %ld%s\n",
 				SVCFH_fmt(&argp->fh),
@@ -215,9 +216,9 @@ nfsd3_proc_write(struct svc_rqst *rqstp, struct nfsd3_writeargs *argp,
 	nfserr = nfsd_write(rqstp, &resp->fh, NULL,
 				   argp->offset,
 				   rqstp->rq_vec, argp->vlen,
-				   argp->len,
+				   &cnt,
 				   &resp->committed);
-	resp->count = argp->count;
+	resp->count = cnt;
 	RETURN_STATUS(nfserr);
 }
 
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 77f584f..283d77a 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -682,6 +682,7 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	struct file *filp = NULL;
 	u32 *p;
 	__be32 status = nfs_ok;
+	unsigned long cnt;
 
 	/* no need to check permission - this will be done in nfsd_write() */
 
@@ -700,7 +701,7 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		return status;
 	}
 
-	write->wr_bytes_written = write->wr_buflen;
+	cnt = write->wr_buflen;
 	write->wr_how_written = write->wr_stable_how;
 	p = (u32 *)write->wr_verifier.data;
 	*p++ = nfssvc_boot.tv_sec;
@@ -708,10 +709,12 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 
 	status =  nfsd_write(rqstp, &cstate->current_fh, filp,
 			     write->wr_offset, rqstp->rq_vec, write->wr_vlen,
-			     write->wr_buflen, &write->wr_how_written);
+			     &cnt, &write->wr_how_written);
 	if (filp)
 		fput(filp);
 
+	write->wr_bytes_written = cnt;
+
 	if (status == nfserr_symlink)
 		status = nfserr_inval;
 	return status;
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 6f7f263..e298e26 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -180,6 +180,7 @@ nfsd_proc_write(struct svc_rqst *rqstp, struct nfsd_writeargs *argp,
 {
 	__be32	nfserr;
 	int	stable = 1;
+	unsigned long cnt = argp->len;
 
 	dprintk("nfsd: WRITE    %s %d bytes at %d\n",
 		SVCFH_fmt(&argp->fh),
@@ -188,7 +189,7 @@ nfsd_proc_write(struct svc_rqst *rqstp, struct nfsd_writeargs *argp,
 	nfserr = nfsd_write(rqstp, fh_copy(&resp->fh, &argp->fh), NULL,
 				   argp->offset,
 				   rqstp->rq_vec, argp->vlen,
-				   argp->len,
+			           &cnt,
 				   &stable);
 	return nfsd_return_attrs(nfserr, resp);
 }
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 0c07629..54404d7 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -960,7 +960,7 @@ static void kill_suid(struct dentry *dentry)
 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, int *stablep)
 {
 	struct svc_export	*exp;
 	struct dentry		*dentry;
@@ -974,7 +974,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	err = nfserr_perm;
 
 	if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) &&
-		(!lock_may_write(file->f_path.dentry->d_inode, offset, cnt)))
+		(!lock_may_write(file->f_path.dentry->d_inode, offset, *cnt)))
 		goto out;
 #endif
 
@@ -1006,7 +1006,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
 	set_fs(oldfs);
 	if (host_err >= 0) {
-		nfsdstats.io_write += cnt;
+		nfsdstats.io_write += host_err;
 		fsnotify_modify(file->f_path.dentry);
 	}
 
@@ -1051,9 +1051,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	}
 
 	dprintk("nfsd: write complete host_err=%d\n", host_err);
-	if (host_err >= 0)
+	if (host_err >= 0) {
 		err = 0;
-	else 
+		*cnt = host_err;
+	} else
 		err = nfserrno(host_err);
 out:
 	return err;
@@ -1095,7 +1096,7 @@ out:
  */
 __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,
+		loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt,
 		int *stablep)
 {
 	__be32			err = 0;
diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h
index 16f7b40..54beda1 100644
--- a/include/linux/nfsd/nfsd.h
+++ b/include/linux/nfsd/nfsd.h
@@ -105,7 +105,7 @@ void		nfsd_close(struct file *);
 __be32 		nfsd_read(struct svc_rqst *, struct svc_fh *, struct file *,
 				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 *, int *);
 __be32		nfsd_readlink(struct svc_rqst *, struct svc_fh *,
 				char *, int *);
 __be32		nfsd_symlink(struct svc_rqst *, struct svc_fh *,


Index: kernel.spec
===================================================================
RCS file: /cvs/pkgs/rpms/kernel/F-11/kernel.spec,v
retrieving revision 1.1642
retrieving revision 1.1643
diff -u -p -r1.1642 -r1.1643
--- kernel.spec	15 Jun 2009 13:11:07 -0000	1.1642
+++ kernel.spec	15 Jun 2009 14:58:17 -0000	1.1643
@@ -747,9 +747,10 @@ Patch5000: linux-2.6-add-qcserial.patch
 Patch6010: squashfs-broken-when-pagesize-greater-than-blocksize.patch
 
 Patch9001: revert-fix-modules_install-via-nfs.patch
+Patch9010: linux-2.6-nfsd-report-short-writes.patch
 
-Patch9002: cpufreq-add-atom-to-p4-clockmod.patch
-Patch9003: linux-2.6-cpufreq-enable-acpi-pstates-on-via.patch
+Patch9100: cpufreq-add-atom-to-p4-clockmod.patch
+Patch9110: linux-2.6-cpufreq-enable-acpi-pstates-on-via.patch
 
 #Adding dropwatch into rawhide until we get to 2.6.30
 Patch9200: linux-2.6-dropwatch-protocol.patch
@@ -1417,6 +1418,9 @@ ApplyPatch squashfs-broken-when-pagesize
 # revert 8b249b6856f16f09b0e5b79ce5f4d435e439b9d6
 ApplyPatch revert-fix-modules_install-via-nfs.patch
 
+# fix nfs reporting of short writes (#493500)
+ApplyPatch linux-2.6-nfsd-report-short-writes.patch
+
 ApplyPatch cpufreq-add-atom-to-p4-clockmod.patch
 ApplyPatch linux-2.6-cpufreq-enable-acpi-pstates-on-via.patch
 
@@ -2026,6 +2030,9 @@ fi
 # and build.
 
 %changelog
+* Mon Jun  15 2009 Chuck Ebbert <cebbert at redhat.com> - 2.6.29.5-181.rc1
+- Fix reporting of short writes to the NFS client (#493500)
+
 * Mon Jun 15 2009 John W. Linville <linville at redhat.com>
 - neigh: fix state transition INCOMPLETE->FAILED via Netlink request