[PATCH 0/2] commit_metadata export operation v3

[PATCH 0/2] commit_metadata export operation v3

[Ben Myers]

Here is the latest version of the knfsd sync changes.  I have addressed the
suggestions provided by Christoph, Trond, and Dave.

Thanks,
	Ben

---

Ben Myers (2):
      commit_metadata export operation replacing nfsd_sync_dir
      xfs_export_operations.commit_metadata


 fs/nfsd/nfs3proc.c            |    2 -
 fs/nfsd/nfs4proc.c            |    2 -
 fs/nfsd/nfs4recover.c         |    4 -
 fs/nfsd/nfs4state.c           |    2 -
 fs/nfsd/nfsproc.c             |    4 +
 fs/nfsd/vfs.c                 |  116 +++++++++++++++++++----------------------
 fs/nfsd/vfs.h                 |    3 -
 fs/xfs/linux-2.6/xfs_export.c |   43 +++++++++++++++
 include/linux/exportfs.h      |    6 ++
 9 files changed, 111 insertions(+), 71 deletions(-)

-- 

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[PATCH 1/2] commit_metadata export operation replacing nfsd_sync_dir

[Ben Myers]

- Add commit_metadata export_operation to allow the underlying filesystem to
  decide how to sync parent and child inodes most efficiently.

- Usage of nfsd_sync_dir and write_inode_now has been replaced with the
  commit_metadata function that takes a svc_fh and optional dentry for the child.

- The commit_metadata function calls the commit_metadata export_op if it's
  there, or else falls back to sync_inode instead of fsync and write_inode_now
  because only metadata need be synched here.

- nfsd4_sync_rec_dir now uses vfs_fsync so that commit_metadata can be static

- Add a 'delay_commit' arg to nfsd_setattr so that callers of
  nfsd_create_setattr can commit parent and child together avoiding an extra
  sync.

Signed-off-by: Ben Myers <bpm@sgi.com>
---
 fs/nfsd/nfs3proc.c       |    2 -
 fs/nfsd/nfs4proc.c       |    2 -
 fs/nfsd/nfs4recover.c    |    4 --
 fs/nfsd/nfs4state.c      |    2 -
 fs/nfsd/nfsproc.c        |    4 +-
 fs/nfsd/vfs.c            |  116 ++++++++++++++++++++++------------------------
 fs/nfsd/vfs.h            |    3 -
 include/linux/exportfs.h |    6 ++
 8 files changed, 68 insertions(+), 71 deletions(-)

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 3d68f45..fe3af23 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -76,7 +76,7 @@ nfsd3_proc_setattr(struct svc_rqst *rqstp, struct nfsd3_sattrargs *argp,
 
 	fh_copy(&resp->fh, &argp->fh);
 	nfserr = nfsd_setattr(rqstp, &resp->fh, &argp->attrs,
-			      argp->check_guard, argp->guardtime);
+			      argp->check_guard, argp->guardtime, 0);
 	RETURN_STATUS(nfserr);
 }
 
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 37514c4..c6e3c7f 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -803,7 +803,7 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	if (status)
 		goto out;
 	status = nfsd_setattr(rqstp, &cstate->current_fh, &setattr->sa_iattr,
-				0, (time_t)0);
+				0, 0, 0);
 out:
 	mnt_drop_write(cstate->current_fh.fh_export->ex_path.mnt);
 	return status;
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 5a754f7..98fb98e 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -119,9 +119,7 @@ out_no_tfm:
 static void
 nfsd4_sync_rec_dir(void)
 {
-	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
-	nfsd_sync_dir(rec_dir.dentry);
-	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
+	vfs_fsync(NULL, rec_dir.dentry, 0);
 }
 
 int
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3a20c09..f2fc8c8 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2290,7 +2290,7 @@ nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh,
 		return 0;
 	if (!(open->op_share_access & NFS4_SHARE_ACCESS_WRITE))
 		return nfserr_inval;
-	return nfsd_setattr(rqstp, fh, &iattr, 0, (time_t)0);
+	return nfsd_setattr(rqstp, fh, &iattr, 0, 0, 0);
 }
 
 static __be32
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index a047ad6..f5e8280 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -69,7 +69,7 @@ nfsd_proc_setattr(struct svc_rqst *rqstp, struct nfsd_sattrargs *argp,
 		argp->attrs.ia_valid, (long) argp->attrs.ia_size);
 
 	fh_copy(&resp->fh, &argp->fh);
-	nfserr = nfsd_setattr(rqstp, &resp->fh, &argp->attrs,0, (time_t)0);
+	nfserr = nfsd_setattr(rqstp, &resp->fh, &argp->attrs, 0, 0, 0);
 	return nfsd_return_attrs(nfserr, resp);
 }
 
@@ -326,7 +326,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp,
 		 */
 		attr->ia_valid &= ATTR_SIZE;
 		if (attr->ia_valid)
-			nfserr = nfsd_setattr(rqstp, newfhp, attr, 0, (time_t)0);
+			nfserr = nfsd_setattr(rqstp, newfhp, attr, 0, 0, 0);
 	}
 
 out_unlock:
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 7062925..734a088 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -27,6 +27,8 @@
 #include <linux/jhash.h>
 #include <linux/ima.h>
 #include <asm/uaccess.h>
+#include <linux/exportfs.h>
+#include <linux/writeback.h>
 
 #ifdef CONFIG_NFSD_V3
 #include "xdr3.h"
@@ -271,6 +273,38 @@ out:
 	return err;
 }
 
+/*
+ * Commit metadata changes to stable storage.  You pay pass NULL for dchild.
+ */
+static int
+commit_metadata(struct svc_fh *fhp, struct dentry *dchild)
+{
+	struct inode *parent = fhp->fh_dentry->d_inode;
+	struct inode *child = NULL;
+	const struct export_operations *export_ops = parent->i_sb->s_export_op;
+	struct writeback_control wbc = {
+		.sync_mode = WB_SYNC_ALL,
+		.nr_to_write = 0, /* metadata only */
+	};
+	int error = 0, error2 = 0;
+
+	if (!EX_ISSYNC(fhp->fh_export))
+		return 0;
+
+	if (dchild) 
+		child = dchild->d_inode;
+
+	if (export_ops->commit_metadata) {
+		error = export_ops->commit_metadata(parent, child);
+	} else {
+		if (child)
+			error2 = sync_inode(child, &wbc);
+		error = sync_inode(parent, &wbc);
+		if (error2)
+			error = error2;
+	}
+	return error;
+}
 
 /*
  * Set various file attributes.
@@ -278,7 +312,7 @@ out:
  */
 __be32
 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
-	     int check_guard, time_t guardtime)
+	     int check_guard, time_t guardtime, int delay_commit)
 {
 	struct dentry	*dentry;
 	struct inode	*inode;
@@ -415,9 +449,8 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 	}
 	if (size_change)
 		put_write_access(inode);
-	if (!err)
-		if (EX_ISSYNC(fhp->fh_export))
-			write_inode_now(inode, 1);
+	if (!err && !delay_commit)
+		err = nfserrno(commit_metadata(fhp, NULL));
 out:
 	return err;
 
@@ -770,28 +803,6 @@ nfsd_close(struct file *filp)
 }
 
 /*
- * Sync a directory to disk.
- *
- * We can't just call vfs_fsync because our requirements are slightly odd:
- *
- *  a) we do not have a file struct available
- *  b) we expect to have i_mutex already held by the caller
- */
-int
-nfsd_sync_dir(struct dentry *dentry)
-{
-	struct inode *inode = dentry->d_inode;
-	int error;
-
-	WARN_ON(!mutex_is_locked(&inode->i_mutex));
-
-	error = filemap_write_and_wait(inode->i_mapping);
-	if (!error && inode->i_fop->fsync)
-		error = inode->i_fop->fsync(NULL, dentry, 0);
-	return error;
-}
-
-/*
  * Obtain the readahead parameters for the file
  * specified by (dev, ino).
  */
@@ -1199,8 +1210,10 @@ nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
 	 */
 	if (current_fsuid() != 0)
 		iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
-	if (iap->ia_valid)
-		return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
+	if (iap->ia_valid) {
+		return nfsd_setattr(rqstp, resfhp, iap, 0, 0,
+				1 /* delay commit. our caller does it. */);
+	}
 	return 0;
 }
 
@@ -1332,12 +1345,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		goto out_nfserr;
 	}
 
-	if (EX_ISSYNC(fhp->fh_export)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
-		write_inode_now(dchild->d_inode, 1);
-	}
-
-	err2 = nfsd_create_setattr(rqstp, resfhp, iap);
+	err = nfsd_create_setattr(rqstp, resfhp, iap);
+	err2 = nfserrno(commit_metadata(fhp, dchild));
 	if (err2)
 		err = err2;
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
@@ -1369,7 +1378,6 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	struct dentry	*dentry, *dchild = NULL;
 	struct inode	*dirp;
 	__be32		err;
-	__be32		err2;
 	int		host_err;
 	__u32		v_mtime=0, v_atime=0;
 
@@ -1464,11 +1472,6 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	if (created)
 		*created = 1;
 
-	if (EX_ISSYNC(fhp->fh_export)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
-		/* setattr will sync the child (or not) */
-	}
-
 	nfsd_check_ignore_resizing(iap);
 
 	if (createmode == NFS3_CREATE_EXCLUSIVE) {
@@ -1483,9 +1486,9 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	}
 
  set_attr:
-	err2 = nfsd_create_setattr(rqstp, resfhp, iap);
-	if (err2)
-		err = err2;
+	err = nfsd_create_setattr(rqstp, resfhp, iap);
+	if (!err) 
+		err = nfserrno(commit_metadata(fhp, dchild));
 
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 	/*
@@ -1600,12 +1603,10 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		}
 	} else
 		host_err = vfs_symlink(dentry->d_inode, dnew, path);
-
-	if (!host_err) {
-		if (EX_ISSYNC(fhp->fh_export))
-			host_err = nfsd_sync_dir(dentry);
-	}
 	err = nfserrno(host_err);
+	if (!err)
+		err = nfserrno(commit_metadata(fhp, NULL));
+
 	fh_unlock(fhp);
 
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
@@ -1667,11 +1668,7 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
 	}
 	host_err = vfs_link(dold, dirp, dnew);
 	if (!host_err) {
-		if (EX_ISSYNC(ffhp->fh_export)) {
-			err = nfserrno(nfsd_sync_dir(ddir));
-			write_inode_now(dest, 1);
-		}
-		err = 0;
+		err = nfserrno(commit_metadata(ffhp, dold));
 	} else {
 		if (host_err == -EXDEV && rqstp->rq_vers == 2)
 			err = nfserr_acces;
@@ -1767,10 +1764,10 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
 		goto out_dput_new;
 
 	host_err = vfs_rename(fdir, odentry, tdir, ndentry);
-	if (!host_err && EX_ISSYNC(tfhp->fh_export)) {
-		host_err = nfsd_sync_dir(tdentry);
+	if (!host_err) {
+		host_err = commit_metadata(tfhp, NULL);
 		if (!host_err)
-			host_err = nfsd_sync_dir(fdentry);
+			host_err = commit_metadata(ffhp, NULL);
 	}
 
 	mnt_drop_write(ffhp->fh_export->ex_path.mnt);
@@ -1851,12 +1848,9 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 
 	dput(rdentry);
 
-	if (host_err)
-		goto out_drop;
-	if (EX_ISSYNC(fhp->fh_export))
-		host_err = nfsd_sync_dir(dentry);
+	if (!host_err)
+		host_err = commit_metadata(fhp, NULL);
 
-out_drop:
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 out_nfserr:
 	err = nfserrno(host_err);
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index 4b1de0a..5062afd 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -41,7 +41,7 @@ __be32		 nfsd_lookup_dentry(struct svc_rqst *, struct svc_fh *,
 				const char *, unsigned int,
 				struct svc_export **, struct dentry **);
 __be32		nfsd_setattr(struct svc_rqst *, struct svc_fh *,
-				struct iattr *, int, time_t);
+				struct iattr *, int, time_t, int);
 int nfsd_mountpoint(struct dentry *, struct svc_export *);
 #ifdef CONFIG_NFSD_V4
 __be32          nfsd4_set_nfs4_acl(struct svc_rqst *, struct svc_fh *,
@@ -91,7 +91,6 @@ __be32		nfsd_statfs(struct svc_rqst *, struct svc_fh *,
 int		nfsd_notify_change(struct inode *, struct iattr *);
 __be32		nfsd_permission(struct svc_rqst *, struct svc_export *,
 				struct dentry *, int);
-int		nfsd_sync_dir(struct dentry *dp);
 
 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 struct posix_acl *nfsd_get_posix_acl(struct svc_fh *, int);
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index dc12f41..9102ecf 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -96,6 +96,7 @@ struct fid {
  * @fh_to_parent:   find the implied object's parent and get a dentry for it
  * @get_name:       find the name for a given inode in a given directory
  * @get_parent:     find the parent of a given directory
+ * @commit_metadata: commit metadata changes to stable storage
  *
  * See Documentation/filesystems/nfs/Exporting for details on how to use
  * this interface correctly.
@@ -137,6 +138,10 @@ struct fid {
  *    is also a directory.  In the event that it cannot be found, or storage
  *    space cannot be allocated, a %ERR_PTR should be returned.
  *
+ * commit_metadata:
+ *    @commit_metadata should commit metadata changes to stable storage.
+ *    Parent or child can be NULL.
+ *
  * Locking rules:
  *    get_parent is called with child->d_inode->i_mutex down
  *    get_name is not (which is possibly inconsistent)
@@ -152,6 +157,7 @@ struct export_operations {
 	int (*get_name)(struct dentry *parent, char *name,
 			struct dentry *child);
 	struct dentry * (*get_parent)(struct dentry *child);
+	int (*commit_metadata)(struct inode *parent, struct inode *child);
 };
 
 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,

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[PATCH 2/2] xfs_export_operations.commit_metadata

[Ben Myers]

This is the commit_metadata export operation for XFS, including the changes
suggested by hch and dgc:

- Takes two two inodes instead of dentries and can assume the parent is
  always set.

- Uses xfs_lock_two_inodes for the ilock.

- Forces the log up to the larger lsn of parent and child.

- Uses XFS_LSN_CMP for lsn comparison.

- Doesn't force the log if nobody had a pincount.

Signed-off-by: Ben Myers <bpm@sgi.com>
---
 fs/xfs/linux-2.6/xfs_export.c |   43 +++++++++++++++++++++++++++++++++++++++++
 1 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_export.c b/fs/xfs/linux-2.6/xfs_export.c
index 87b8cbd..d37ced1 100644
--- a/fs/xfs/linux-2.6/xfs_export.c
+++ b/fs/xfs/linux-2.6/xfs_export.c
@@ -29,6 +29,7 @@
 #include "xfs_vnodeops.h"
 #include "xfs_bmap_btree.h"
 #include "xfs_inode.h"
+#include "xfs_inode_item.h"
 
 /*
  * Note that we only accept fileids which are long enough rather than allow
@@ -215,9 +216,51 @@ xfs_fs_get_parent(
 	return d_obtain_alias(VFS_I(cip));
 }
 
+STATIC int
+xfs_fs_nfs_commit_metadata(
+	struct inode		*parent,
+	struct inode		*child)
+{
+	struct xfs_inode	*dp = XFS_I(parent);
+	struct xfs_inode	*ip = NULL;
+	struct xfs_mount	*mp = dp->i_mount;
+	xfs_lsn_t		force_lsn = NULLCOMMITLSN;
+	int			error = 0;
+
+	if (child) {
+		ip = XFS_I(child);
+		xfs_lock_two_inodes(dp, ip, XFS_ILOCK_SHARED);
+	} else {
+		xfs_ilock(dp, XFS_ILOCK_SHARED);
+	}
+
+	if (xfs_ipincount(dp)) {
+		force_lsn = dp->i_itemp->ili_last_lsn;
+		if (ip && xfs_ipincount(ip) &&
+		    XFS_LSN_CMP(force_lsn, ip->i_itemp->ili_last_lsn) < 0) {
+			force_lsn = ip->i_itemp->ili_last_lsn;
+		}
+	} else if (ip && xfs_ipincount(ip)) {
+		force_lsn = ip->i_itemp->ili_last_lsn;
+	}
+
+	if (force_lsn != NULLCOMMITLSN) {
+		error = _xfs_log_force(mp, force_lsn,
+				XFS_LOG_FORCE | XFS_LOG_SYNC, NULL);
+	}
+
+	if (child)
+		xfs_iunlock(ip, XFS_ILOCK_SHARED);
+	if (parent)
+		xfs_iunlock(dp, XFS_ILOCK_SHARED);
+
+	return error;
+}
+
 const struct export_operations xfs_export_operations = {
 	.encode_fh		= xfs_fs_encode_fh,
 	.fh_to_dentry		= xfs_fs_fh_to_dentry,
 	.fh_to_parent		= xfs_fs_fh_to_parent,
 	.get_parent		= xfs_fs_get_parent,
+	.commit_metadata	= xfs_fs_nfs_commit_metadata,
 };

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Re: [PATCH 0/2] commit_metadata export operation v3

[Trond Myklebust]

On Thu, 2010-02-11 at 13:26 -0600, Ben Myers wrote: 
> Here is the latest version of the knfsd sync changes.  I have addressed the
> suggestions provided by Christoph, Trond, and Dave.
> 
> Thanks,
> 	Ben

Hi Ben,

This looks good to me, but before you send it on to Bruce, you might
want to try rebasing this against his for-2.6.34 branch. That branch
contains the stuff that is queued up for the next merge window, and
includes Christoph's vfs_fsync() changes and my vfs_fsync_range() change
to nfsd_commit().

See
http://git.linux-nfs.org/?p=bfields/linux.git;a=shortlog;h=refs/heads/for-2.6.34

Cheers
  Trond

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[PATCH 1/2] commit_metadata export operation replacing nfsd_sync_dir

[Ben Myers]

- Add commit_metadata export_operation to allow the underlying filesystem to
decide how to sync parent and child inodes most efficiently.

- Usage of nfsd_sync_dir and write_inode_now has been replaced with the
commit_metadata function that takes a svc_fh and optional dentry for the child.

- The commit_metadata function calls the commit_metadata export_op if it's
there, or else falls back to sync_inode instead of fsync and write_inode_now
because only metadata need be synched here.

- nfsd4_sync_rec_dir now uses vfs_fsync so that commit_metadata can be static

- Add a 'delay_commit' arg to nfsd_setattr so that callers of
nfsd_create_setattr can commit parent and child together avoiding an extra
sync.

Signed-off-by: Ben Myers <bpm@sgi.com>
---
 fs/nfsd/nfs3proc.c       |    2 -
 fs/nfsd/nfs4proc.c       |    2 -
 fs/nfsd/nfs4recover.c    |    4 --
 fs/nfsd/nfs4state.c      |    2 -
 fs/nfsd/nfsproc.c        |    4 +-
 fs/nfsd/vfs.c            |  116 ++++++++++++++++++++++------------------------
 fs/nfsd/vfs.h            |    3 -
 include/linux/exportfs.h |    6 ++
 8 files changed, 68 insertions(+), 71 deletions(-)

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 3d68f45..fe3af23 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -76,7 +76,7 @@ nfsd3_proc_setattr(struct svc_rqst *rqstp, struct nfsd3_sattrargs *argp,
 
 	fh_copy(&resp->fh, &argp->fh);
 	nfserr = nfsd_setattr(rqstp, &resp->fh, &argp->attrs,
-			      argp->check_guard, argp->guardtime);
+			      argp->check_guard, argp->guardtime, 0);
 	RETURN_STATUS(nfserr);
 }
 
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 37514c4..c6e3c7f 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -803,7 +803,7 @@ nfsd4_setattr(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	if (status)
 		goto out;
 	status = nfsd_setattr(rqstp, &cstate->current_fh, &setattr->sa_iattr,
-				0, (time_t)0);
+				0, 0, 0);
 out:
 	mnt_drop_write(cstate->current_fh.fh_export->ex_path.mnt);
 	return status;
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 5a754f7..98fb98e 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -119,9 +119,7 @@ out_no_tfm:
 static void
 nfsd4_sync_rec_dir(void)
 {
-	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
-	nfsd_sync_dir(rec_dir.dentry);
-	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
+	vfs_fsync(NULL, rec_dir.dentry, 0);
 }
 
 int
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3a20c09..f2fc8c8 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2290,7 +2290,7 @@ nfsd4_truncate(struct svc_rqst *rqstp, struct svc_fh *fh,
 		return 0;
 	if (!(open->op_share_access & NFS4_SHARE_ACCESS_WRITE))
 		return nfserr_inval;
-	return nfsd_setattr(rqstp, fh, &iattr, 0, (time_t)0);
+	return nfsd_setattr(rqstp, fh, &iattr, 0, 0, 0);
 }
 
 static __be32
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index a047ad6..f5e8280 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -69,7 +69,7 @@ nfsd_proc_setattr(struct svc_rqst *rqstp, struct nfsd_sattrargs *argp,
 		argp->attrs.ia_valid, (long) argp->attrs.ia_size);
 
 	fh_copy(&resp->fh, &argp->fh);
-	nfserr = nfsd_setattr(rqstp, &resp->fh, &argp->attrs,0, (time_t)0);
+	nfserr = nfsd_setattr(rqstp, &resp->fh, &argp->attrs, 0, 0, 0);
 	return nfsd_return_attrs(nfserr, resp);
 }
 
@@ -326,7 +326,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp,
 		 */
 		attr->ia_valid &= ATTR_SIZE;
 		if (attr->ia_valid)
-			nfserr = nfsd_setattr(rqstp, newfhp, attr, 0, (time_t)0);
+			nfserr = nfsd_setattr(rqstp, newfhp, attr, 0, 0, 0);
 	}
 
 out_unlock:
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index ed024d3..97474fb 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -27,6 +27,8 @@
 #include <linux/jhash.h>
 #include <linux/ima.h>
 #include <asm/uaccess.h>
+#include <linux/exportfs.h>
+#include <linux/writeback.h>
 
 #ifdef CONFIG_NFSD_V3
 #include "xdr3.h"
@@ -271,6 +273,38 @@ out:
 	return err;
 }
 
+/*
+ * Commit metadata changes to stable storage.  You pay pass NULL for dchild.
+ */
+static int
+commit_metadata(struct svc_fh *fhp, struct dentry *dchild)
+{
+	struct inode *parent = fhp->fh_dentry->d_inode;
+	struct inode *child = NULL;
+	const struct export_operations *export_ops = parent->i_sb->s_export_op;
+	struct writeback_control wbc = {
+		.sync_mode = WB_SYNC_ALL,
+		.nr_to_write = 0, /* metadata only */
+	};
+	int error = 0, error2 = 0;
+
+	if (!EX_ISSYNC(fhp->fh_export))
+		return 0;
+
+	if (dchild) 
+		child = dchild->d_inode;
+
+	if (export_ops->commit_metadata) {
+		error = export_ops->commit_metadata(parent, child);
+	} else {
+		if (child)
+			error2 = sync_inode(child, &wbc);
+		error = sync_inode(parent, &wbc);
+		if (error2)
+			error = error2;
+	}
+	return error;
+}
 
 /*
  * Set various file attributes.
@@ -278,7 +312,7 @@ out:
  */
 __be32
 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
-	     int check_guard, time_t guardtime)
+	     int check_guard, time_t guardtime, int delay_commit)
 {
 	struct dentry	*dentry;
 	struct inode	*inode;
@@ -415,9 +449,8 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 	}
 	if (size_change)
 		put_write_access(inode);
-	if (!err)
-		if (EX_ISSYNC(fhp->fh_export))
-			write_inode_now(inode, 1);
+	if (!err && !delay_commit)
+		err = nfserrno(commit_metadata(fhp, NULL));
 out:
 	return err;
 
@@ -769,28 +802,6 @@ nfsd_close(struct file *filp)
 }
 
 /*
- * Sync a directory to disk.
- *
- * We can't just call vfs_fsync because our requirements are slightly odd:
- *
- *  a) we do not have a file struct available
- *  b) we expect to have i_mutex already held by the caller
- */
-int
-nfsd_sync_dir(struct dentry *dentry)
-{
-	struct inode *inode = dentry->d_inode;
-	int error;
-
-	WARN_ON(!mutex_is_locked(&inode->i_mutex));
-
-	error = filemap_write_and_wait(inode->i_mapping);
-	if (!error && inode->i_fop->fsync)
-		error = inode->i_fop->fsync(NULL, dentry, 0);
-	return error;
-}
-
-/*
  * Obtain the readahead parameters for the file
  * specified by (dev, ino).
  */
@@ -1198,8 +1209,10 @@ nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
 	 */
 	if (current_fsuid() != 0)
 		iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
-	if (iap->ia_valid)
-		return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
+	if (iap->ia_valid) {
+		return nfsd_setattr(rqstp, resfhp, iap, 0, 0,
+				1 /* delay commit. our caller does it. */);
+	}
 	return 0;
 }
 
@@ -1331,12 +1344,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		goto out_nfserr;
 	}
 
-	if (EX_ISSYNC(fhp->fh_export)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
-		write_inode_now(dchild->d_inode, 1);
-	}
-
-	err2 = nfsd_create_setattr(rqstp, resfhp, iap);
+	err = nfsd_create_setattr(rqstp, resfhp, iap);
+	err2 = nfserrno(commit_metadata(fhp, dchild));
 	if (err2)
 		err = err2;
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
@@ -1368,7 +1377,6 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	struct dentry	*dentry, *dchild = NULL;
 	struct inode	*dirp;
 	__be32		err;
-	__be32		err2;
 	int		host_err;
 	__u32		v_mtime=0, v_atime=0;
 
@@ -1463,11 +1471,6 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	if (created)
 		*created = 1;
 
-	if (EX_ISSYNC(fhp->fh_export)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
-		/* setattr will sync the child (or not) */
-	}
-
 	nfsd_check_ignore_resizing(iap);
 
 	if (createmode == NFS3_CREATE_EXCLUSIVE) {
@@ -1482,9 +1485,9 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	}
 
  set_attr:
-	err2 = nfsd_create_setattr(rqstp, resfhp, iap);
-	if (err2)
-		err = err2;
+	err = nfsd_create_setattr(rqstp, resfhp, iap);
+	if (!err) 
+		err = nfserrno(commit_metadata(fhp, dchild));
 
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 	/*
@@ -1599,12 +1602,10 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		}
 	} else
 		host_err = vfs_symlink(dentry->d_inode, dnew, path);
-
-	if (!host_err) {
-		if (EX_ISSYNC(fhp->fh_export))
-			host_err = nfsd_sync_dir(dentry);
-	}
 	err = nfserrno(host_err);
+	if (!err)
+		err = nfserrno(commit_metadata(fhp, NULL));
+
 	fh_unlock(fhp);
 
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
@@ -1666,11 +1667,7 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
 	}
 	host_err = vfs_link(dold, dirp, dnew);
 	if (!host_err) {
-		if (EX_ISSYNC(ffhp->fh_export)) {
-			err = nfserrno(nfsd_sync_dir(ddir));
-			write_inode_now(dest, 1);
-		}
-		err = 0;
+		err = nfserrno(commit_metadata(ffhp, dold));
 	} else {
 		if (host_err == -EXDEV && rqstp->rq_vers == 2)
 			err = nfserr_acces;
@@ -1766,10 +1763,10 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
 		goto out_dput_new;
 
 	host_err = vfs_rename(fdir, odentry, tdir, ndentry);
-	if (!host_err && EX_ISSYNC(tfhp->fh_export)) {
-		host_err = nfsd_sync_dir(tdentry);
+	if (!host_err) {
+		host_err = commit_metadata(tfhp, NULL);
 		if (!host_err)
-			host_err = nfsd_sync_dir(fdentry);
+			host_err = commit_metadata(ffhp, NULL);
 	}
 
 	mnt_drop_write(ffhp->fh_export->ex_path.mnt);
@@ -1850,12 +1847,9 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 
 	dput(rdentry);
 
-	if (host_err)
-		goto out_drop;
-	if (EX_ISSYNC(fhp->fh_export))
-		host_err = nfsd_sync_dir(dentry);
+	if (!host_err)
+		host_err = commit_metadata(fhp, NULL);
 
-out_drop:
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 out_nfserr:
 	err = nfserrno(host_err);
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index 4b1de0a..5062afd 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -41,7 +41,7 @@ __be32		 nfsd_lookup_dentry(struct svc_rqst *, struct svc_fh *,
 				const char *, unsigned int,
 				struct svc_export **, struct dentry **);
 __be32		nfsd_setattr(struct svc_rqst *, struct svc_fh *,
-				struct iattr *, int, time_t);
+				struct iattr *, int, time_t, int);
 int nfsd_mountpoint(struct dentry *, struct svc_export *);
 #ifdef CONFIG_NFSD_V4
 __be32          nfsd4_set_nfs4_acl(struct svc_rqst *, struct svc_fh *,
@@ -91,7 +91,6 @@ __be32		nfsd_statfs(struct svc_rqst *, struct svc_fh *,
 int		nfsd_notify_change(struct inode *, struct iattr *);
 __be32		nfsd_permission(struct svc_rqst *, struct svc_export *,
 				struct dentry *, int);
-int		nfsd_sync_dir(struct dentry *dp);
 
 #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
 struct posix_acl *nfsd_get_posix_acl(struct svc_fh *, int);
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index dc12f41..9102ecf 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -96,6 +96,7 @@ struct fid {
  * @fh_to_parent:   find the implied object's parent and get a dentry for it
  * @get_name:       find the name for a given inode in a given directory
  * @get_parent:     find the parent of a given directory
+ * @commit_metadata: commit metadata changes to stable storage
  *
  * See Documentation/filesystems/nfs/Exporting for details on how to use
  * this interface correctly.
@@ -137,6 +138,10 @@ struct fid {
  *    is also a directory.  In the event that it cannot be found, or storage
  *    space cannot be allocated, a %ERR_PTR should be returned.
  *
+ * commit_metadata:
+ *    @commit_metadata should commit metadata changes to stable storage.
+ *    Parent or child can be NULL.
+ *
  * Locking rules:
  *    get_parent is called with child->d_inode->i_mutex down
  *    get_name is not (which is possibly inconsistent)
@@ -152,6 +157,7 @@ struct export_operations {
 	int (*get_name)(struct dentry *parent, char *name,
 			struct dentry *child);
 	struct dentry * (*get_parent)(struct dentry *child);
+	int (*commit_metadata)(struct inode *parent, struct inode *child);
 };
 
 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,

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Re: [PATCH 1/2] commit_metadata export operation replacing nfsd_sync_dir

[Alex Elder]

Generally this looks like a good change, but I do have
some questions embedded below.

					-Alex

On Thu, 2010-02-11 at 16:05 -0600, Ben Myers wrote:
> - Add commit_metadata export_operation to allow the underlying filesystem to
> decide how to sync parent and child inodes most efficiently.
> 
> - Usage of nfsd_sync_dir and write_inode_now has been replaced with the
> commit_metadata function that takes a svc_fh and optional dentry for the child.

In the cases you pass the child dentry, you will now be syncing
things to disk in a slightly different way/order from before.
I think this way is actually much better, but I thought I'd ask
anyway:  are you sure that it's OK to sync them at the same time,
rather than directory first, then child (or the other way around,
depending on the case)?

> - The commit_metadata function calls the commit_metadata export_op if it's
> there, or else falls back to sync_inode instead of fsync and write_inode_now
> because only metadata need be synched here.
> 
> - nfsd4_sync_rec_dir now uses vfs_fsync so that commit_metadata can be static
> 
> - Add a 'delay_commit' arg to nfsd_setattr so that callers of
> nfsd_create_setattr can commit parent and child together avoiding an extra
> sync.

I think this is a distinct enough change to warrant a separate patch
from the commit_metadata feature.

> 
> Signed-off-by: Ben Myers <bpm@sgi.com>

. . .

> index 5a754f7..98fb98e 100644
> --- a/fs/nfsd/nfs4recover.c
> +++ b/fs/nfsd/nfs4recover.c
> @@ -119,9 +119,7 @@ out_no_tfm:
>  static void
>  nfsd4_sync_rec_dir(void)
>  {
> -	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
> -	nfsd_sync_dir(rec_dir.dentry);
> -	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
> +	vfs_fsync(NULL, rec_dir.dentry, 0);

Why do you no longer need to acquire the mutex here?
I see it gets acquired during the ->fsync() call
inside vfs_fsync_range(), but is there a reason
that it needed to be held during the filemap_write_and_wait()
(as is done in the nfsd_sync_dir() code) also?

. . .

> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index ed024d3..97474fb 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c

. . .

> @@ -415,9 +449,8 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
>  	}
>  	if (size_change)
>  		put_write_access(inode);
> -	if (!err)
> -		if (EX_ISSYNC(fhp->fh_export))
> -			write_inode_now(inode, 1);
> +	if (!err && !delay_commit)
> +		err = nfserrno(commit_metadata(fhp, NULL));

Is this sufficient even if the size has changed?

>  out:
>  	return err;
>  

. . .

> @@ -1766,10 +1763,10 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
>  		goto out_dput_new;
>  
>  	host_err = vfs_rename(fdir, odentry, tdir, ndentry);
> -	if (!host_err && EX_ISSYNC(tfhp->fh_export)) {
> -		host_err = nfsd_sync_dir(tdentry);
> +	if (!host_err) {
> +		host_err = commit_metadata(tfhp, NULL);
>  		if (!host_err)
> -			host_err = nfsd_sync_dir(fdentry);
> +			host_err = commit_metadata(ffhp, NULL);

It violates the spirit of the "parent" and "child"
nature of its arguments, but it might be nice to
commit both directories' metadata with the same
call here.

. . .

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Re: [PATCH 1/2] commit_metadata export operation replacing nfsd_sync_dir

[Christoph Hellwig]

> In the cases you pass the child dentry, you will now be syncing
> things to disk in a slightly different way/order from before.
> I think this way is actually much better, but I thought I'd ask
> anyway:  are you sure that it's OK to sync them at the same time,
> rather than directory first, then child (or the other way around,
> depending on the case)?

The order is defined by when we commit the transactions, if we do
the log force on the later one first we already write out the first
transaction.  Note that in any transaction filesystems the changes
that create/mkdir/link/unlink do to parent and child will be in
the same transaction anyway, which is kinda the point of adding
the transactions to start with.  Only for the case where we do
a setattr in addition to the primary transaction we'll actually
have another transaction to deal with and the above applies.

> >  nfsd4_sync_rec_dir(void)
> >  {
> > -	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
> > -	nfsd_sync_dir(rec_dir.dentry);
> > -	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
> > +	vfs_fsync(NULL, rec_dir.dentry, 0);
> 
> Why do you no longer need to acquire the mutex here?
> I see it gets acquired during the ->fsync() call
> inside vfs_fsync_range(), but is there a reason
> that it needed to be held during the filemap_write_and_wait()
> (as is done in the nfsd_sync_dir() code) also?

We don't need i_mutex for filemap_write_and_wait, it's just held
because someone used the nfsd_sync_dir helper where it doesn't
fit very well.

> > @@ -415,9 +449,8 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
> >  	}
> >  	if (size_change)
> >  		put_write_access(inode);
> > -	if (!err)
> > -		if (EX_ISSYNC(fhp->fh_export))
> > -			write_inode_now(inode, 1);
> > +	if (!err && !delay_commit)
> > +		err = nfserrno(commit_metadata(fhp, NULL));
> 
> Is this sufficient even if the size has changed?

Yes.

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[PATCH 1/2] commit_metadata export operation replacing nfsd_sync_dir

[Ben Myers]

- Add commit_metadata export_operation to allow the underlying filesystem to
decide how to commit an inode most efficiently.

- Usage of nfsd_sync_dir and write_inode_now has been replaced with the
commit_metadata function that takes a svc_fh.

- The commit_metadata function calls the commit_metadata export_op if it's
there, or else falls back to sync_inode instead of fsync and write_inode_now
because only metadata need be synced here.

- nfsd4_sync_rec_dir now uses vfs_fsync so that commit_metadata can be static

Signed-off-by: Ben Myers <bpm@sgi.com>
---
 fs/nfsd/nfs4recover.c    |    4 --
 fs/nfsd/vfs.c            |  109 ++++++++++++++++++++++------------------------
 include/linux/exportfs.h |    5 ++
 3 files changed, 59 insertions(+), 59 deletions(-)

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 5a754f7..98fb98e 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -119,9 +119,7 @@ out_no_tfm:
 static void
 nfsd4_sync_rec_dir(void)
 {
-	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
-	nfsd_sync_dir(rec_dir.dentry);
-	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
+	vfs_fsync(NULL, rec_dir.dentry, 0);
 }
 
 int
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index ed024d3..cde275b 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -27,6 +27,8 @@
 #include <linux/jhash.h>
 #include <linux/ima.h>
 #include <asm/uaccess.h>
+#include <linux/exportfs.h>
+#include <linux/writeback.h>
 
 #ifdef CONFIG_NFSD_V3
 #include "xdr3.h"
@@ -271,6 +273,31 @@ out:
 	return err;
 }
 
+/*
+ * Commit metadata changes to stable storage.  You pay pass NULL for dchild.
+ */
+static int
+commit_metadata(struct svc_fh *fhp)
+{
+	struct inode *inode = fhp->fh_dentry->d_inode;
+	const struct export_operations *export_ops = inode->i_sb->s_export_op;
+	struct writeback_control wbc = {
+		.sync_mode = WB_SYNC_ALL,
+		.nr_to_write = 0, /* metadata only */
+	};
+	int error = 0;
+
+	if (!EX_ISSYNC(fhp->fh_export))
+		return 0;
+
+	if (export_ops->commit_metadata) {
+		error = export_ops->commit_metadata(inode);
+	} else {
+		error = sync_inode(inode, &wbc);
+	}
+
+	return error;
+}
 
 /*
  * Set various file attributes.
@@ -769,28 +796,6 @@ nfsd_close(struct file *filp)
 }
 
 /*
- * Sync a directory to disk.
- *
- * We can't just call vfs_fsync because our requirements are slightly odd:
- *
- *  a) we do not have a file struct available
- *  b) we expect to have i_mutex already held by the caller
- */
-int
-nfsd_sync_dir(struct dentry *dentry)
-{
-	struct inode *inode = dentry->d_inode;
-	int error;
-
-	WARN_ON(!mutex_is_locked(&inode->i_mutex));
-
-	error = filemap_write_and_wait(inode->i_mapping);
-	if (!error && inode->i_fop->fsync)
-		error = inode->i_fop->fsync(NULL, dentry, 0);
-	return error;
-}
-
-/*
  * Obtain the readahead parameters for the file
  * specified by (dev, ino).
  */
@@ -1199,7 +1204,7 @@ nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
 	if (current_fsuid() != 0)
 		iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
 	if (iap->ia_valid)
-		return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
+		return nfsd_setattr(rqstp, resfhp, iap, 0, 0);
 	return 0;
 }
 
@@ -1331,13 +1336,15 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		goto out_nfserr;
 	}
 
-	if (EX_ISSYNC(fhp->fh_export)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
-		write_inode_now(dchild->d_inode, 1);
-	}
+	err = nfsd_create_setattr(rqstp, resfhp, iap);
 
-	err2 = nfsd_create_setattr(rqstp, resfhp, iap);
-	if (err2)
+	/*
+	 * nfsd_setattr already committed the child.  Transactional filesystems
+	 * had a chance to commit changes for both parent and child
+	 * simultaneously making the following commit_metadata a noop.
+	 */
+	err2 = nfserrno(commit_metadata(fhp));
+       	if (err2)
 		err = err2;
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 	/*
@@ -1368,7 +1375,6 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	struct dentry	*dentry, *dchild = NULL;
 	struct inode	*dirp;
 	__be32		err;
-	__be32		err2;
 	int		host_err;
 	__u32		v_mtime=0, v_atime=0;
 
@@ -1463,11 +1469,6 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	if (created)
 		*created = 1;
 
-	if (EX_ISSYNC(fhp->fh_export)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
-		/* setattr will sync the child (or not) */
-	}
-
 	nfsd_check_ignore_resizing(iap);
 
 	if (createmode == NFS3_CREATE_EXCLUSIVE) {
@@ -1482,9 +1483,13 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	}
 
  set_attr:
-	err2 = nfsd_create_setattr(rqstp, resfhp, iap);
-	if (err2)
-		err = err2;
+	err = nfsd_create_setattr(rqstp, resfhp, iap);
+
+	/*
+	 * nfsd_setattr already committed the child (and possibly also the parent).
+	 */
+	if (!err)
+		err = nfserrno(commit_metadata(fhp));
 
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 	/*
@@ -1599,12 +1604,9 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		}
 	} else
 		host_err = vfs_symlink(dentry->d_inode, dnew, path);
-
-	if (!host_err) {
-		if (EX_ISSYNC(fhp->fh_export))
-			host_err = nfsd_sync_dir(dentry);
-	}
 	err = nfserrno(host_err);
+	if (!err)
+		err = nfserrno(commit_metadata(fhp));
 	fh_unlock(fhp);
 
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
@@ -1666,11 +1668,9 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
 	}
 	host_err = vfs_link(dold, dirp, dnew);
 	if (!host_err) {
-		if (EX_ISSYNC(ffhp->fh_export)) {
-			err = nfserrno(nfsd_sync_dir(ddir));
-			write_inode_now(dest, 1);
-		}
-		err = 0;
+		err = nfserrno(commit_metadata(ffhp));
+		if (!err)
+			err = nfserrno(commit_metadata(tfhp));
 	} else {
 		if (host_err == -EXDEV && rqstp->rq_vers == 2)
 			err = nfserr_acces;
@@ -1766,10 +1766,10 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
 		goto out_dput_new;
 
 	host_err = vfs_rename(fdir, odentry, tdir, ndentry);
-	if (!host_err && EX_ISSYNC(tfhp->fh_export)) {
-		host_err = nfsd_sync_dir(tdentry);
+	if (!host_err) {
+		host_err = commit_metadata(tfhp);
 		if (!host_err)
-			host_err = nfsd_sync_dir(fdentry);
+			host_err = commit_metadata(ffhp);
 	}
 
 	mnt_drop_write(ffhp->fh_export->ex_path.mnt);
@@ -1850,12 +1850,9 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 
 	dput(rdentry);
 
-	if (host_err)
-		goto out_drop;
-	if (EX_ISSYNC(fhp->fh_export))
-		host_err = nfsd_sync_dir(dentry);
+	if (!host_err)
+		host_err = commit_metadata(fhp);
 
-out_drop:
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 out_nfserr:
 	err = nfserrno(host_err);
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index dc12f41..a9cd507 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -96,6 +96,7 @@ struct fid {
  * @fh_to_parent:   find the implied object's parent and get a dentry for it
  * @get_name:       find the name for a given inode in a given directory
  * @get_parent:     find the parent of a given directory
+ * @commit_metadata: commit metadata changes to stable storage
  *
  * See Documentation/filesystems/nfs/Exporting for details on how to use
  * this interface correctly.
@@ -137,6 +138,9 @@ struct fid {
  *    is also a directory.  In the event that it cannot be found, or storage
  *    space cannot be allocated, a %ERR_PTR should be returned.
  *
+ * commit_metadata:
+ *    @commit_metadata should commit metadata changes to stable storage.
+ *
  * Locking rules:
  *    get_parent is called with child->d_inode->i_mutex down
  *    get_name is not (which is possibly inconsistent)
@@ -152,6 +156,7 @@ struct export_operations {
 	int (*get_name)(struct dentry *parent, char *name,
 			struct dentry *child);
 	struct dentry * (*get_parent)(struct dentry *child);
+	int (*commit_metadata)(struct inode *inode);
 };
 
 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,

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Re: [PATCH 1/2] commit_metadata export operation replacing nfsd_sync_dir

[Christoph Hellwig]

This looks very good to me.  A couple of tiny nitpicks below:


> +/*
> + * Commit metadata changes to stable storage.  You pay pass NULL for dchild.
> + */

The dchild argument is gone in this version.

> +	struct writeback_control wbc = {
> +		.sync_mode = WB_SYNC_ALL,
> +		.nr_to_write = 0, /* metadata only */
> +	};
> +	int error = 0;
> +
> +	if (!EX_ISSYNC(fhp->fh_export))
> +		return 0;
> +
> +	if (export_ops->commit_metadata) {
> +		error = export_ops->commit_metadata(inode);
> +	} else {
> +		error = sync_inode(inode, &wbc);
> +	}

Maybe move the wbc declaration into the else branch here to keep
variables in the smallest possible scope.

> @@ -1199,7 +1204,7 @@ nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
>  	if (current_fsuid() != 0)
>  		iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
>  	if (iap->ia_valid)
> -		return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
> +		return nfsd_setattr(rqstp, resfhp, iap, 0, 0);

While this is a worthwhile cleanup I'd not put it into a patch that is
now entirely unrelated.

> +	err = nfsd_create_setattr(rqstp, resfhp, iap);
>  
> +	/*
> +	 * nfsd_setattr already committed the child.  Transactional filesystems
> +	 * had a chance to commit changes for both parent and child
> +	 * simultaneously making the following commit_metadata a noop.
> +	 */
> +	err2 = nfserrno(commit_metadata(fhp));
> +       	if (err2)
>  		err = err2;

The if statement above seems rather minindented, possibly due to the
partial use of spaces instead of tabs.

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[PATCH 1/2] commit_metadata export operation replacing nfsd_sync_dir

[Ben Myers]

- Add commit_metadata export_operation to allow the underlying filesystem to
decide how to commit an inode most efficiently.

- Usage of nfsd_sync_dir and write_inode_now has been replaced with the
commit_metadata function that takes a svc_fh.

- The commit_metadata function calls the commit_metadata export_op if it's
there, or else falls back to sync_inode instead of fsync and write_inode_now
because only metadata need be synced here.

- nfsd4_sync_rec_dir now uses vfs_fsync so that commit_metadata can be static

Signed-off-by: Ben Myers <bpm@sgi.com>
---
 fs/nfsd/nfs4recover.c    |    4 --
 fs/nfsd/vfs.c            |  106 +++++++++++++++++++++++-----------------------
 include/linux/exportfs.h |    5 ++
 3 files changed, 58 insertions(+), 57 deletions(-)

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 5a754f7..98fb98e 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -119,9 +119,7 @@ out_no_tfm:
 static void
 nfsd4_sync_rec_dir(void)
 {
-	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
-	nfsd_sync_dir(rec_dir.dentry);
-	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
+	vfs_fsync(NULL, rec_dir.dentry, 0);
 }
 
 int
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index ed024d3..8afdba5 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -27,6 +27,8 @@
 #include <linux/jhash.h>
 #include <linux/ima.h>
 #include <asm/uaccess.h>
+#include <linux/exportfs.h>
+#include <linux/writeback.h>
 
 #ifdef CONFIG_NFSD_V3
 #include "xdr3.h"
@@ -271,6 +273,32 @@ out:
 	return err;
 }
 
+/*
+ * Commit metadata changes to stable storage.
+ */
+static int
+commit_metadata(struct svc_fh *fhp)
+{
+	struct inode *inode = fhp->fh_dentry->d_inode;
+	const struct export_operations *export_ops = inode->i_sb->s_export_op;
+	int error = 0;
+
+	if (!EX_ISSYNC(fhp->fh_export))
+		return 0;
+
+	if (export_ops->commit_metadata) {
+		error = export_ops->commit_metadata(inode);
+	} else {
+		struct writeback_control wbc = {
+			.sync_mode = WB_SYNC_ALL,
+			.nr_to_write = 0, /* metadata only */
+		};
+
+		error = sync_inode(inode, &wbc);
+	}
+
+	return error;
+}
 
 /*
  * Set various file attributes.
@@ -769,28 +797,6 @@ nfsd_close(struct file *filp)
 }
 
 /*
- * Sync a directory to disk.
- *
- * We can't just call vfs_fsync because our requirements are slightly odd:
- *
- *  a) we do not have a file struct available
- *  b) we expect to have i_mutex already held by the caller
- */
-int
-nfsd_sync_dir(struct dentry *dentry)
-{
-	struct inode *inode = dentry->d_inode;
-	int error;
-
-	WARN_ON(!mutex_is_locked(&inode->i_mutex));
-
-	error = filemap_write_and_wait(inode->i_mapping);
-	if (!error && inode->i_fop->fsync)
-		error = inode->i_fop->fsync(NULL, dentry, 0);
-	return error;
-}
-
-/*
  * Obtain the readahead parameters for the file
  * specified by (dev, ino).
  */
@@ -1331,12 +1337,14 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		goto out_nfserr;
 	}
 
-	if (EX_ISSYNC(fhp->fh_export)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
-		write_inode_now(dchild->d_inode, 1);
-	}
+	err = nfsd_create_setattr(rqstp, resfhp, iap);
 
-	err2 = nfsd_create_setattr(rqstp, resfhp, iap);
+	/*
+	 * nfsd_setattr already committed the child.  Transactional filesystems
+	 * had a chance to commit changes for both parent and child
+	 * simultaneously making the following commit_metadata a noop.
+	 */
+	err2 = nfserrno(commit_metadata(fhp));
 	if (err2)
 		err = err2;
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
@@ -1368,7 +1376,6 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	struct dentry	*dentry, *dchild = NULL;
 	struct inode	*dirp;
 	__be32		err;
-	__be32		err2;
 	int		host_err;
 	__u32		v_mtime=0, v_atime=0;
 
@@ -1463,11 +1470,6 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	if (created)
 		*created = 1;
 
-	if (EX_ISSYNC(fhp->fh_export)) {
-		err = nfserrno(nfsd_sync_dir(dentry));
-		/* setattr will sync the child (or not) */
-	}
-
 	nfsd_check_ignore_resizing(iap);
 
 	if (createmode == NFS3_CREATE_EXCLUSIVE) {
@@ -1482,9 +1484,13 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	}
 
  set_attr:
-	err2 = nfsd_create_setattr(rqstp, resfhp, iap);
-	if (err2)
-		err = err2;
+	err = nfsd_create_setattr(rqstp, resfhp, iap);
+
+	/*
+	 * nfsd_setattr already committed the child (and possibly also the parent).
+	 */
+	if (!err)
+		err = nfserrno(commit_metadata(fhp));
 
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 	/*
@@ -1599,12 +1605,9 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
 		}
 	} else
 		host_err = vfs_symlink(dentry->d_inode, dnew, path);
-
-	if (!host_err) {
-		if (EX_ISSYNC(fhp->fh_export))
-			host_err = nfsd_sync_dir(dentry);
-	}
 	err = nfserrno(host_err);
+	if (!err)
+		err = nfserrno(commit_metadata(fhp));
 	fh_unlock(fhp);
 
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
@@ -1666,11 +1669,9 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
 	}
 	host_err = vfs_link(dold, dirp, dnew);
 	if (!host_err) {
-		if (EX_ISSYNC(ffhp->fh_export)) {
-			err = nfserrno(nfsd_sync_dir(ddir));
-			write_inode_now(dest, 1);
-		}
-		err = 0;
+		err = nfserrno(commit_metadata(ffhp));
+		if (!err)
+			err = nfserrno(commit_metadata(tfhp));
 	} else {
 		if (host_err == -EXDEV && rqstp->rq_vers == 2)
 			err = nfserr_acces;
@@ -1766,10 +1767,10 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
 		goto out_dput_new;
 
 	host_err = vfs_rename(fdir, odentry, tdir, ndentry);
-	if (!host_err && EX_ISSYNC(tfhp->fh_export)) {
-		host_err = nfsd_sync_dir(tdentry);
+	if (!host_err) {
+		host_err = commit_metadata(tfhp);
 		if (!host_err)
-			host_err = nfsd_sync_dir(fdentry);
+			host_err = commit_metadata(ffhp);
 	}
 
 	mnt_drop_write(ffhp->fh_export->ex_path.mnt);
@@ -1850,12 +1851,9 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 
 	dput(rdentry);
 
-	if (host_err)
-		goto out_drop;
-	if (EX_ISSYNC(fhp->fh_export))
-		host_err = nfsd_sync_dir(dentry);
+	if (!host_err)
+		host_err = commit_metadata(fhp);
 
-out_drop:
 	mnt_drop_write(fhp->fh_export->ex_path.mnt);
 out_nfserr:
 	err = nfserrno(host_err);
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index dc12f41..a9cd507 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -96,6 +96,7 @@ struct fid {
  * @fh_to_parent:   find the implied object's parent and get a dentry for it
  * @get_name:       find the name for a given inode in a given directory
  * @get_parent:     find the parent of a given directory
+ * @commit_metadata: commit metadata changes to stable storage
  *
  * See Documentation/filesystems/nfs/Exporting for details on how to use
  * this interface correctly.
@@ -137,6 +138,9 @@ struct fid {
  *    is also a directory.  In the event that it cannot be found, or storage
  *    space cannot be allocated, a %ERR_PTR should be returned.
  *
+ * commit_metadata:
+ *    @commit_metadata should commit metadata changes to stable storage.
+ *
  * Locking rules:
  *    get_parent is called with child->d_inode->i_mutex down
  *    get_name is not (which is possibly inconsistent)
@@ -152,6 +156,7 @@ struct export_operations {
 	int (*get_name)(struct dentry *parent, char *name,
 			struct dentry *child);
 	struct dentry * (*get_parent)(struct dentry *child);
+	int (*commit_metadata)(struct inode *inode);
 };
 
 extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,

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