[PATCH 1/2] commit_metadata export operation replacing nfsd_sync_dir

Ben Myers
2010-02-11T22:05:04Z

- 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,