nfs: make nfs_path() work without vfsmount

part 3: now we have everything to get nfs_path() just by dentry -
just follow to (disconnected) root and pick the rest of the thing
there.

Start killing propagation of struct vfsmount * on the paths that
used to bring it to nfs_path().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 19 insertions, 24 deletions

diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 3c2a1724fbd..46942e2680a 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -54,33 +54,29 @@ Elong:
 /*
  * Determine the mount path as a string
  */
-static char *nfs4_path(const struct vfsmount *mnt_parent,
-		       const struct dentry *dentry,
-		       char *buffer, ssize_t buflen)
+static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
 {
-	const char *srvpath;
-
-	srvpath = strchr(mnt_parent->mnt_devname, ':');
-	if (srvpath)
-		srvpath++;
-	else
-		srvpath = mnt_parent->mnt_devname;
-
-	return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
+	char *limit;
+	char *path = nfs_path(&limit, dentry, buffer, buflen);
+	if (!IS_ERR(path)) {
+		char *colon = strchr(path, ':');
+		if (colon && colon < limit)
+			path = colon + 1;
+	}
+	return path;
 }
 
 /*
  * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
  * believe to be the server path to this dentry
  */
-static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
-				const struct dentry *dentry,
+static int nfs4_validate_fspath(struct dentry *dentry,
 				const struct nfs4_fs_locations *locations,
 				char *page, char *page2)
 {
 	const char *path, *fs_path;
 
-	path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
+	path = nfs4_path(dentry, page, PAGE_SIZE);
 	if (IS_ERR(path))
 		return PTR_ERR(path);
 
@@ -165,20 +161,20 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
 
 /**
  * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
- * @mnt_parent - mountpoint of parent directory
+ * @sb - superblock of parent directory
  * @dentry - parent directory
  * @locations - array of NFSv4 server location information
  *
  */
-static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
-					    const struct dentry *dentry,
+static struct vfsmount *nfs_follow_referral(struct super_block *sb,
+					    struct dentry *dentry,
 					    const struct nfs4_fs_locations *locations)
 {
 	struct vfsmount *mnt = ERR_PTR(-ENOENT);
 	struct nfs_clone_mount mountdata = {
-		.sb = mnt_parent->mnt_sb,
+		.sb = sb,
 		.dentry = dentry,
-		.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
+		.authflavor = NFS_SB(sb)->client->cl_auth->au_flavor,
 	};
 	char *page = NULL, *page2 = NULL;
 	int loc, error;
@@ -198,7 +194,7 @@ static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
 		goto out;
 
 	/* Ensure fs path is a prefix of current dentry path */
-	error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
+	error = nfs4_validate_fspath(dentry, locations, page, page2);
 	if (error < 0) {
 		mnt = ERR_PTR(error);
 		goto out;
@@ -225,11 +221,10 @@ out:
 
 /*
  * nfs_do_refmount - handle crossing a referral on server
- * @mnt_parent - mountpoint of referral
  * @dentry - dentry of referral
  *
  */
-struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
+struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry)
 {
 	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
 	struct dentry *parent;
@@ -262,7 +257,7 @@ struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentr
 	    fs_locations->fs_path.ncomponents <= 0)
 		goto out_free;
 
-	mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
+	mnt = nfs_follow_referral(sb, dentry, fs_locations);
 out_free:
 	__free_page(page);
 	kfree(fs_locations);