[PATCH 01/12] HPPFS: procfs acquiring superblock cleanups

[Paolo 'Blaisorblade' Giarrusso]

From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>, Al Viro

Cleanup dirty dricks to get a procfs superblock to wrap read/write
operations from procfs, and pass a mntget(proc_mnt) instead of NULL to
dentry_open.

Actually, since Al had suggested creating a vfsmount on our own, while I
found that proc_mnt already exists for this purpose and is initialized very
early, I use that, unless it is still NULL. We could probably drop this
check (but not the mntget() at each dentry_open(), since it expects this,
and can mntput() on error).

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>
---

 fs/hppfs/hppfs_kern.c |   38 ++++++++++++++++++++++++--------------
 1 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/fs/hppfs/hppfs_kern.c b/fs/hppfs/hppfs_kern.c
--- a/fs/hppfs/hppfs_kern.c
+++ b/fs/hppfs/hppfs_kern.c
@@ -13,6 +13,7 @@
 #include <linux/ctype.h>
 #include <linux/dcache.h>
 #include <linux/statfs.h>
+#include <linux/mount.h>
 #include <asm/uaccess.h>
 #include <asm/fcntl.h>
 #include "os.h"
@@ -44,6 +45,7 @@ static inline struct hppfs_inode_info *H
 #define HPPFS_SUPER_MAGIC 0xb00000ee
 
 static struct super_operations hppfs_sbops;
+static struct vfsmount * proc_submnt;
 
 static int is_pid(struct dentry *dentry)
 {
@@ -472,7 +474,7 @@ static int hppfs_open(struct inode *inod
 	proc_dentry = HPPFS_I(inode)->proc_dentry;
 
 	/* XXX This isn't closed anywhere */
-	data->proc_file = dentry_open(dget(proc_dentry), NULL,
+	data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_submnt),
 				      file_mode(file->f_mode));
 	err = PTR_ERR(data->proc_file);
 	if(IS_ERR(data->proc_file))
@@ -526,7 +528,7 @@ static int hppfs_dir_open(struct inode *
 		goto out;
 
 	proc_dentry = HPPFS_I(inode)->proc_dentry;
-	data->proc_file = dentry_open(dget(proc_dentry), NULL,
+	data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_submnt),
 				      file_mode(file->f_mode));
 	err = PTR_ERR(data->proc_file);
 	if(IS_ERR(data->proc_file))
@@ -665,7 +667,7 @@ static int hppfs_readlink(struct dentry 
 	int ret;
 
 	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
-	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
+	proc_file = dentry_open(dget(proc_dentry), mntget(proc_submnt), O_RDONLY);
 	if (IS_ERR(proc_file))
 		return PTR_ERR(proc_file);
 
@@ -683,7 +685,7 @@ static void* hppfs_follow_link(struct de
 	void *ret;
 
 	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
-	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
+	proc_file = dentry_open(dget(proc_dentry), mntget(proc_submnt), O_RDONLY);
 	if (IS_ERR(proc_file))
 		return proc_file;
 
@@ -726,20 +728,12 @@ static int init_inode(struct inode *inod
 static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
 {
 	struct inode *root_inode;
-	struct file_system_type *procfs;
 	struct super_block *proc_sb;
 	int err;
 
 	err = -ENOENT;
-	procfs = get_fs_type("proc");
-	if(procfs == NULL)
-		goto out;
-
-	if(list_empty(&procfs->fs_supers))
-		goto out;
 
-	proc_sb = list_entry(procfs->fs_supers.next, struct super_block,
-			     s_instances);
+	proc_sb = proc_submnt->mnt_sb;
 
 	sb->s_blocksize = 1024;
 	sb->s_blocksize_bits = 10;
@@ -786,12 +780,28 @@ static struct file_system_type hppfs_typ
 
 static int __init init_hppfs(void)
 {
-	return(register_filesystem(&hppfs_type));
+	int ret;
+	proc_submnt = do_kern_mount("proc", 0, "proc", NULL);
+
+	if (IS_ERR(proc_submnt)) {
+		ret = PTR_ERR(proc_submnt);
+		goto err;
+	}
+
+	ret = register_filesystem(&hppfs_type);
+	if (ret)
+		goto err_put;
+	return 0;
+err_put:
+	mntput(proc_submnt);
+err:
+	return ret;
 }
 
 static void __exit exit_hppfs(void)
 {
 	unregister_filesystem(&hppfs_type);
+	mntput(proc_submnt);
 }
 
 module_init(init_hppfs)

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