[PATCH] sanitize hppfs

* hppfs_iget() and its users are racy; there's no need to pollute icache
  anyway, new_inode() works fine and is safe, unlike the current kludges
  (these relied on overwriting ->i_ino before another iget_locked() gets
  to that one - and did it after unlocking).
* merge hppfs_iget()/init_inode()/hppfs_read_inode(), while we are
  at it.
* to pass proper vfsmount to dentry_open() store the reference
  in hppfs superblock.

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

1 files changed, 34 insertions, 79 deletions

diff --git a/fs/hppfs/hppfs_kern.c b/fs/hppfs/hppfs_kern.c
index 0c0f62f5164f..8601d8ef3b55 100644
--- a/fs/hppfs/hppfs_kern.c
+++ b/fs/hppfs/hppfs_kern.c
@@ -18,8 +18,7 @@
 #include <asm/uaccess.h>
 #include "os.h"
 
-static int init_inode(struct inode *inode, struct dentry *dentry,
-                      struct vfsmount *mnt);
+static struct inode *get_inode(struct super_block *, struct dentry *);
 
 struct hppfs_data {
         struct list_head list;
@@ -35,7 +34,6 @@ struct hppfs_private {
 
 struct hppfs_inode_info {
         struct dentry *proc_dentry;
-        struct vfsmount *proc_mnt;
         struct inode vfs_inode;
 };
 
@@ -137,40 +135,6 @@ static int file_removed(struct dentry *dentry, const char *file)
         return 0;
 }
 
-static void hppfs_read_inode(struct inode *ino)
-{
-        struct inode *proc_ino;
-
-        if (HPPFS_I(ino)->proc_dentry == NULL)
-                return;
-
-        proc_ino = HPPFS_I(ino)->proc_dentry->d_inode;
-        ino->i_uid = proc_ino->i_uid;
-        ino->i_gid = proc_ino->i_gid;
-        ino->i_atime = proc_ino->i_atime;
-        ino->i_mtime = proc_ino->i_mtime;
-        ino->i_ctime = proc_ino->i_ctime;
-        ino->i_ino = proc_ino->i_ino;
-        ino->i_mode = proc_ino->i_mode;
-        ino->i_nlink = proc_ino->i_nlink;
-        ino->i_size = proc_ino->i_size;
-        ino->i_blocks = proc_ino->i_blocks;
-}
-
-static struct inode *hppfs_iget(struct super_block *sb)
-{
-        struct inode *inode;
-
-        inode = iget_locked(sb, 0);
-        if (!inode)
-                return ERR_PTR(-ENOMEM);
-        if (inode->i_state & I_NEW) {
-                hppfs_read_inode(inode);
-                unlock_new_inode(inode);
-        }
-        return inode;
-}
-
 static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
                                   struct nameidata *nd)
 {
@@ -206,23 +170,14 @@ static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
         if (IS_ERR(proc_dentry))
                 return proc_dentry;
 
-        inode = hppfs_iget(ino->i_sb);
-        if (IS_ERR(inode)) {
-                err = PTR_ERR(inode);
+        err = -ENOMEM;
+        inode = get_inode(ino->i_sb, proc_dentry);
+        if (!inode)
                 goto out_dput;
-        }
-
-        err = init_inode(inode, proc_dentry, HPPFS_I(ino)->proc_mnt);
-        if (err)
-                goto out_put;
-
-        hppfs_read_inode(inode);
 
         d_add(dentry, inode);
         return NULL;
 
- out_put:
-        iput(inode);
  out_dput:
         dput(proc_dentry);
  out:
@@ -489,7 +444,7 @@ static int hppfs_open(struct inode *inode, struct file *file)
                 goto out_free2;
 
         proc_dentry = HPPFS_I(inode)->proc_dentry;
-        proc_mnt = HPPFS_I(inode)->proc_mnt;
+        proc_mnt = inode->i_sb->s_fs_info;
 
         /* XXX This isn't closed anywhere */
         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
@@ -547,7 +502,7 @@ static int hppfs_dir_open(struct inode *inode, struct file *file)
                 goto out;
 
         proc_dentry = HPPFS_I(inode)->proc_dentry;
-        proc_mnt = HPPFS_I(inode)->proc_mnt;
+        proc_mnt = inode->i_sb->s_fs_info;
         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
                                       file_mode(file->f_mode));
         err = PTR_ERR(data->proc_file);
@@ -659,7 +614,6 @@ static struct inode *hppfs_alloc_inode(struct super_block *sb)
                 return NULL;
 
         hi->proc_dentry = NULL;
-        hi->proc_mnt = NULL;
         inode_init_once(&hi->vfs_inode);
         return &hi->vfs_inode;
 }
@@ -676,7 +630,7 @@ static void hppfs_destroy_inode(struct inode *inode)
 
 static void hppfs_put_super(struct super_block *sb)
 {
-        mntput(HPPFS_I(sb->s_root->d_inode)->proc_mnt);
+        mntput(sb->s_fs_info);
 }
 
 static const struct super_operations hppfs_sbops = {
@@ -696,7 +650,7 @@ static int hppfs_readlink(struct dentry *dentry, char __user *buffer,
         int ret;
 
         proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
-        proc_mnt = HPPFS_I(dentry->d_inode)->proc_mnt;
+        proc_mnt = dentry->d_sb->s_fs_info;
 
         proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt), O_RDONLY);
         if (IS_ERR(proc_file))
@@ -717,7 +671,7 @@ static void* hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
         void *ret;
 
         proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
-        proc_mnt = HPPFS_I(dentry->d_inode)->proc_mnt;
+        proc_mnt = dentry->d_sb->s_fs_info;
 
         proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt), O_RDONLY);
         if (IS_ERR(proc_file))
@@ -739,9 +693,14 @@ static const struct inode_operations hppfs_link_iops = {
         .follow_link    = hppfs_follow_link,
 };
 
-static int init_inode(struct inode *inode, struct dentry *dentry,
-                struct vfsmount *mnt)
+static struct inode *get_inode(struct super_block *sb, struct dentry *dentry)
 {
+        struct inode *proc_ino = dentry->d_inode;
+        struct inode *inode = new_inode(sb);
+
+        if (!inode)
+                return ERR_PTR(-ENOMEM);
+
         if (S_ISDIR(dentry->d_inode->i_mode)) {
                 inode->i_op = &hppfs_dir_iops;
                 inode->i_fop = &hppfs_dir_fops;
@@ -754,7 +713,17 @@ static int init_inode(struct inode *inode, struct dentry *dentry,
         }
 
         HPPFS_I(inode)->proc_dentry = dentry;
-        HPPFS_I(inode)->proc_mnt = mnt;
+
+        inode->i_uid = proc_ino->i_uid;
+        inode->i_gid = proc_ino->i_gid;
+        inode->i_atime = proc_ino->i_atime;
+        inode->i_mtime = proc_ino->i_mtime;
+        inode->i_ctime = proc_ino->i_ctime;
+        inode->i_ino = proc_ino->i_ino;
+        inode->i_mode = proc_ino->i_mode;
+        inode->i_nlink = proc_ino->i_nlink;
+        inode->i_size = proc_ino->i_size;
+        inode->i_blocks = proc_ino->i_blocks;
 
         return 0;
 }
@@ -762,17 +731,10 @@ static int init_inode(struct inode *inode, struct dentry *dentry,
 static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
 {
         struct inode *root_inode;
-        struct file_system_type *procfs;
         struct vfsmount *proc_mnt;
-        int err;
+        int err = -ENOENT;
 
-        err = -ENOENT;
-        procfs = get_fs_type("proc");
-        if (!procfs)
-                goto out;
-
-        proc_mnt = vfs_kern_mount(procfs, 0, procfs->name, NULL);
-        put_filesystem(procfs);
+        proc_mnt = do_kern_mount("proc", 0, "proc", NULL);
         if (IS_ERR(proc_mnt))
                 goto out;
 
@@ -780,24 +742,17 @@ static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
         sb->s_blocksize_bits = 10;
         sb->s_magic = HPPFS_SUPER_MAGIC;
         sb->s_op = &hppfs_sbops;
-
-        root_inode = hppfs_iget(sb);
-        if (IS_ERR(root_inode)) {
-                err = PTR_ERR(root_inode);
-                goto out;
-        }
-
-        err = init_inode(root_inode, proc_mnt->mnt_sb->s_root, proc_mnt);
-        if (err)
-                goto out_iput;
+        sb->s_fs_info = proc_mnt;
 
         err = -ENOMEM;
+        root_inode = get_inode(sb, proc_mnt->mnt_sb->s_root);
+        if (!root_inode)
+                goto out_mntput;
+
         sb->s_root = d_alloc_root(root_inode);
         if (!sb->s_root)
                 goto out_iput;
 
-        hppfs_read_inode(root_inode);
-
         return 0;
 
  out_iput: