pass a struct path to vfs_statfs

We'll need the path to implement the flags field for statvfs support.
We do have it available in all callers except:

 - ecryptfs_statfs.  This one doesn't actually need vfs_statfs but just
   needs to do a caller to the lower filesystem statfs method.
 - sys_ustat.  Add a non-exported statfs_by_dentry helper for it which
   doesn't won't be able to fill out the flags field later on.

In addition rename the helpers for statfs vs fstatfs to do_*statfs instead
of the misleading vfs prefix.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

7 files changed, 55 insertions, 35 deletions

diff --git a/fs/cachefiles/bind.c b/fs/cachefiles/bind.c
index 2906077..a2603e7 100644
--- a/fs/cachefiles/bind.c
+++ b/fs/cachefiles/bind.c
@@ -146,7 +146,7 @@ static int cachefiles_daemon_add_cache(struct cachefiles_cache *cache)
 		goto error_unsupported;
 
 	/* get the cache size and blocksize */
-	ret = vfs_statfs(root, &stats);
+	ret = vfs_statfs(&path, &stats);
 	if (ret < 0)
 		goto error_unsupported;
 
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index c241356..24eb0d3 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -683,6 +683,10 @@ int cachefiles_has_space(struct cachefiles_cache *cache,
 			 unsigned fnr, unsigned bnr)
 {
 	struct kstatfs stats;
+	struct path path = {
+		.mnt	= cache->mnt,
+		.dentry	= cache->mnt->mnt_root,
+	};
 	int ret;
 
 	//_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u",
@@ -697,7 +701,7 @@ int cachefiles_has_space(struct cachefiles_cache *cache,
 	/* find out how many pages of blockdev are available */
 	memset(&stats, 0, sizeof(stats));
 
-	ret = vfs_statfs(cache->mnt->mnt_root, &stats);
+	ret = vfs_statfs(&path, &stats);
 	if (ret < 0) {
 		if (ret == -EIO)
 			cachefiles_io_error(cache, "statfs failed");
diff --git a/fs/compat.c b/fs/compat.c
index 6490d21..fc6c2ad 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -266,7 +266,7 @@ asmlinkage long compat_sys_statfs(const char __user *pathname, struct compat_sta
 	error = user_path(pathname, &path);
 	if (!error) {
 		struct kstatfs tmp;
-		error = vfs_statfs(path.dentry, &tmp);
+		error = vfs_statfs(&path, &tmp);
 		if (!error)
 			error = put_compat_statfs(buf, &tmp);
 		path_put(&path);
@@ -284,7 +284,7 @@ asmlinkage long compat_sys_fstatfs(unsigned int fd, struct compat_statfs __user
 	file = fget(fd);
 	if (!file)
 		goto out;
-	error = vfs_statfs(file->f_path.dentry, &tmp);
+	error = vfs_statfs(&file->f_path, &tmp);
 	if (!error)
 		error = put_compat_statfs(buf, &tmp);
 	fput(file);
@@ -334,7 +334,7 @@ asmlinkage long compat_sys_statfs64(const char __user *pathname, compat_size_t s
 	error = user_path(pathname, &path);
 	if (!error) {
 		struct kstatfs tmp;
-		error = vfs_statfs(path.dentry, &tmp);
+		error = vfs_statfs(&path, &tmp);
 		if (!error)
 			error = put_compat_statfs64(buf, &tmp);
 		path_put(&path);
@@ -355,7 +355,7 @@ asmlinkage long compat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct c
 	file = fget(fd);
 	if (!file)
 		goto out;
-	error = vfs_statfs(file->f_path.dentry, &tmp);
+	error = vfs_statfs(&file->f_path, &tmp);
 	if (!error)
 		error = put_compat_statfs64(buf, &tmp);
 	fput(file);
@@ -378,7 +378,7 @@ asmlinkage long compat_sys_ustat(unsigned dev, struct compat_ustat __user *u)
 	sb = user_get_super(new_decode_dev(dev));
 	if (!sb)
 		return -EINVAL;
-	err = vfs_statfs(sb->s_root, &sbuf);
+	err = statfs_by_dentry(sb->s_root, &sbuf);
 	drop_super(sb);
 	if (err)
 		return err;
diff --git a/fs/ecryptfs/super.c b/fs/ecryptfs/super.c
index 4b5de6c..f7fc286 100644
--- a/fs/ecryptfs/super.c
+++ b/fs/ecryptfs/super.c
@@ -118,7 +118,11 @@ void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode)
  */
 static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
-	return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf);
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+
+	if (!lower_dentry->d_sb->s_op->statfs)
+		return -ENOSYS;
+	return lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
 }
 
 /**
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index ac17a70..4d6154f 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1756,6 +1756,10 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
 	struct nfs4_acl *acl = NULL;
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
 	u32 minorversion = resp->cstate.minorversion;
+	struct path path = {
+		.mnt	= exp->ex_path.mnt,
+		.dentry	= dentry,
+	};
 
 	BUG_ON(bmval1 & NFSD_WRITEONLY_ATTRS_WORD1);
 	BUG_ON(bmval0 & ~nfsd_suppattrs0(minorversion));
@@ -1776,7 +1780,7 @@ nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
 			FATTR4_WORD0_MAXNAME)) ||
 	    (bmval1 & (FATTR4_WORD1_SPACE_AVAIL | FATTR4_WORD1_SPACE_FREE |
 		       FATTR4_WORD1_SPACE_TOTAL))) {
-		err = vfs_statfs(dentry, &statfs);
+		err = vfs_statfs(&path, &statfs);
 		if (err)
 			goto out_nfserr;
 	}
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 3c11112..f6f1a71 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -2019,8 +2019,14 @@ out:
 __be32
 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access)
 {
-	__be32 err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
-	if (!err && vfs_statfs(fhp->fh_dentry,stat))
+	struct path path = {
+		.mnt	= fhp->fh_export->ex_path.mnt,
+		.dentry	= fhp->fh_dentry,
+	};
+	__be32 err;
+
+	err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access);
+	if (!err && vfs_statfs(&path, stat))
 		err = nfserr_io;
 	return err;
 }
diff --git a/fs/statfs.c b/fs/statfs.c
index 4ef021f..6a30570 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -7,33 +7,35 @@
 #include <linux/security.h>
 #include <linux/uaccess.h>
 
-int vfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
 {
-	int retval = -ENODEV;
-
-	if (dentry) {
-		retval = -ENOSYS;
-		if (dentry->d_sb->s_op->statfs) {
-			memset(buf, 0, sizeof(*buf));
-			retval = security_sb_statfs(dentry);
-			if (retval)
-				return retval;
-			retval = dentry->d_sb->s_op->statfs(dentry, buf);
-			if (retval == 0 && buf->f_frsize == 0)
-				buf->f_frsize = buf->f_bsize;
-		}
-	}
+	int retval;
+
+	if (!dentry->d_sb->s_op->statfs)
+		return -ENOSYS;
+
+	memset(buf, 0, sizeof(*buf));
+	retval = security_sb_statfs(dentry);
+	if (retval)
+		return retval;
+	retval = dentry->d_sb->s_op->statfs(dentry, buf);
+	if (retval == 0 && buf->f_frsize == 0)
+		buf->f_frsize = buf->f_bsize;
 	return retval;
 }
 
+int vfs_statfs(struct path *path, struct kstatfs *buf)
+{
+	return statfs_by_dentry(path->dentry, buf);
+}
 EXPORT_SYMBOL(vfs_statfs);
 
-static int vfs_statfs_native(struct dentry *dentry, struct statfs *buf)
+static int do_statfs_native(struct path *path, struct statfs *buf)
 {
 	struct kstatfs st;
 	int retval;
 
-	retval = vfs_statfs(dentry, &st);
+	retval = vfs_statfs(path, &st);
 	if (retval)
 		return retval;
 
@@ -72,12 +74,12 @@ static int vfs_statfs_native(struct dentry *dentry, struct statfs *buf)
 	return 0;
 }
 
-static int vfs_statfs64(struct dentry *dentry, struct statfs64 *buf)
+static int do_statfs64(struct path *path, struct statfs64 *buf)
 {
 	struct kstatfs st;
 	int retval;
 
-	retval = vfs_statfs(dentry, &st);
+	retval = vfs_statfs(path, &st);
 	if (retval)
 		return retval;
 
@@ -107,7 +109,7 @@ SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, b
 	error = user_path(pathname, &path);
 	if (!error) {
 		struct statfs tmp;
-		error = vfs_statfs_native(path.dentry, &tmp);
+		error = do_statfs_native(&path, &tmp);
 		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
 			error = -EFAULT;
 		path_put(&path);
@@ -125,7 +127,7 @@ SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct stat
 	error = user_path(pathname, &path);
 	if (!error) {
 		struct statfs64 tmp;
-		error = vfs_statfs64(path.dentry, &tmp);
+		error = do_statfs64(&path, &tmp);
 		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
 			error = -EFAULT;
 		path_put(&path);
@@ -143,7 +145,7 @@ SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
 	file = fget(fd);
 	if (!file)
 		goto out;
-	error = vfs_statfs_native(file->f_path.dentry, &tmp);
+	error = do_statfs_native(&file->f_path, &tmp);
 	if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
 		error = -EFAULT;
 	fput(file);
@@ -164,7 +166,7 @@ SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user
 	file = fget(fd);
 	if (!file)
 		goto out;
-	error = vfs_statfs64(file->f_path.dentry, &tmp);
+	error = do_statfs64(&file->f_path, &tmp);
 	if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
 		error = -EFAULT;
 	fput(file);
@@ -183,7 +185,7 @@ SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
 	if (!s)
 		return -EINVAL;
 
-	err = vfs_statfs(s->s_root, &sbuf);
+	err = statfs_by_dentry(s->s_root, &sbuf);
 	drop_super(s);
 	if (err)
 		return err;