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Commit f501912a authored by Ben Myers's avatar Ben Myers Committed by J. Bruce Fields
Browse files

commit_metadata export operation replacing nfsd_sync_dir 



- 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: default avatarBen Myers <bpm@sgi.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
parent 7e469af9

fs/nfsd/nfs4recover.c

+1 −3
Original line number Diff line number Diff line
@@ -119,9 +119,7 @@ nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname) 
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

fs/nfsd/vfs.c

+52 −54
Original line number Diff line number Diff line
@@ -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 @@ nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name, 
	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.
@@ -768,28 +796,6 @@ nfsd_close(struct file *filp) 
	fput(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);

include/linux/exportfs.h

+5 −0
Original line number Diff line number Diff line
@@ -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,