uml: hppfs fixes

hppfs tidying and fixes noticed during hch's get_inode work -
      style fixes
      a copy_to_user got its return value checked
      hppfs_write no longer fiddles file->f_pos because it gets and
returns pos in its arguments
      hppfs_delete_inode dputs the underlyng procfs dentry stored in
its private data and mntputs the vfsmnt stashed in s_fs_info
      hppfs_put_super no longer needs to mntput the s_fs_info, so it
no longer needs to exist
      hppfs_readlink and hppfs_follow_link were doing a bunch of stuff
with a struct file which they didn't use
      there is now a ->permission which calls generic_permission
      get_inode was always returning 0 for some reason - it now
returns an inode if nothing bad happened

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 52 deletions

diff --git a/fs/hppfs/hppfs_kern.c b/fs/hppfs/hppfs_kern.c
index 8601d8ef3b55..65077aa90f0a 100644
--- a/fs/hppfs/hppfs_kern.c
+++ b/fs/hppfs/hppfs_kern.c
@@ -33,7 +33,7 @@ struct hppfs_private {
 };
 
 struct hppfs_inode_info {
-        struct dentry *proc_dentry;
+        struct dentry *proc_dentry;
         struct inode vfs_inode;
 };
 
@@ -52,7 +52,7 @@ static int is_pid(struct dentry *dentry)
         int i;
 
         sb = dentry->d_sb;
-        if ((sb->s_op != &hppfs_sbops) || (dentry->d_parent != sb->s_root))
+        if (dentry->d_parent != sb->s_root)
                 return 0;
 
         for (i = 0; i < dentry->d_name.len; i++) {
@@ -136,7 +136,7 @@ static int file_removed(struct dentry *dentry, const char *file)
 }
 
 static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
-                                  struct nameidata *nd)
+                                   struct nameidata *nd)
 {
         struct dentry *proc_dentry, *new, *parent;
         struct inode *inode;
@@ -254,6 +254,8 @@ static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
         int err;
 
         if (hppfs->contents != NULL) {
+                int rem;
+
                 if (*ppos >= hppfs->len)
                         return 0;
 
@@ -267,8 +269,10 @@ static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
 
                 if (off + count > hppfs->len)
                         count = hppfs->len - off;
-                copy_to_user(buf, &data->contents[off], count);
-                *ppos += count;
+                rem = copy_to_user(buf, &data->contents[off], count);
+                *ppos += count - rem;
+                if (rem > 0)
+                        return -EFAULT;
         } else if (hppfs->host_fd != -1) {
                 err = os_seek_file(hppfs->host_fd, *ppos);
                 if (err) {
@@ -285,21 +289,15 @@ static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
         return count;
 }
 
-static ssize_t hppfs_write(struct file *file, const char __user *buf, size_t len,
-                           loff_t *ppos)
+static ssize_t hppfs_write(struct file *file, const char __user *buf,
+                           size_t len, loff_t *ppos)
 {
         struct hppfs_private *data = file->private_data;
         struct file *proc_file = data->proc_file;
         ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
-        int err;
 
         write = proc_file->f_path.dentry->d_inode->i_fop->write;
-
-        proc_file->f_pos = file->f_pos;
-        err = (*write)(proc_file, buf, len, &proc_file->f_pos);
-        file->f_pos = proc_file->f_pos;
-
-        return err;
+        return (*write)(proc_file, buf, len, ppos);
 }
 
 static int open_host_sock(char *host_file, int *filter_out)
@@ -357,7 +355,7 @@ static struct hppfs_data *hppfs_get_data(int fd, int filter,
 
         if (filter) {
                 while ((n = read_proc(proc_file, data->contents,
-                                     sizeof(data->contents), NULL, 0)) > 0)
+                                      sizeof(data->contents), NULL, 0)) > 0)
                         os_write_file(fd, data->contents, n);
                 err = os_shutdown_socket(fd, 0, 1);
                 if (err) {
@@ -429,8 +427,8 @@ static int file_mode(int fmode)
 static int hppfs_open(struct inode *inode, struct file *file)
 {
         struct hppfs_private *data;
-        struct dentry *proc_dentry;
         struct vfsmount *proc_mnt;
+        struct dentry *proc_dentry;
         char *host_file;
         int err, fd, type, filter;
 
@@ -492,8 +490,8 @@ static int hppfs_open(struct inode *inode, struct file *file)
 static int hppfs_dir_open(struct inode *inode, struct file *file)
 {
         struct hppfs_private *data;
-        struct dentry *proc_dentry;
         struct vfsmount *proc_mnt;
+        struct dentry *proc_dentry;
         int err;
 
         err = -ENOMEM;
@@ -620,6 +618,9 @@ static struct inode *hppfs_alloc_inode(struct super_block *sb)
 
 void hppfs_delete_inode(struct inode *ino)
 {
+        dput(HPPFS_I(ino)->proc_dentry);
+        mntput(ino->i_sb->s_fs_info);
+
         clear_inode(ino);
 }
 
@@ -628,69 +629,46 @@ static void hppfs_destroy_inode(struct inode *inode)
         kfree(HPPFS_I(inode));
 }
 
-static void hppfs_put_super(struct super_block *sb)
-{
-        mntput(sb->s_fs_info);
-}
-
 static const struct super_operations hppfs_sbops = {
         .alloc_inode    = hppfs_alloc_inode,
         .destroy_inode  = hppfs_destroy_inode,
         .delete_inode   = hppfs_delete_inode,
         .statfs         = hppfs_statfs,
-        .put_super      = hppfs_put_super,
 };
 
 static int hppfs_readlink(struct dentry *dentry, char __user *buffer,
                           int buflen)
 {
-        struct file *proc_file;
         struct dentry *proc_dentry;
-        struct vfsmount *proc_mnt;
-        int ret;
 
         proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
-        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))
-                return PTR_ERR(proc_file);
-
-        ret = proc_dentry->d_inode->i_op->readlink(proc_dentry, buffer, buflen);
-
-        fput(proc_file);
-
-        return ret;
+        return proc_dentry->d_inode->i_op->readlink(proc_dentry, buffer,
+                                                    buflen);
 }
 
-static void* hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
+static void *hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
-        struct file *proc_file;
         struct dentry *proc_dentry;
-        struct vfsmount *proc_mnt;
-        void *ret;
 
         proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
-        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))
-                return proc_file;
-
-        ret = proc_dentry->d_inode->i_op->follow_link(proc_dentry, nd);
 
-        fput(proc_file);
+        return proc_dentry->d_inode->i_op->follow_link(proc_dentry, nd);
+}
 
-        return ret;
+int hppfs_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+        return generic_permission(inode, mask, NULL);
 }
 
 static const struct inode_operations hppfs_dir_iops = {
         .lookup         = hppfs_lookup,
+        .permission     = hppfs_permission,
 };
 
 static const struct inode_operations hppfs_link_iops = {
         .readlink       = hppfs_readlink,
         .follow_link    = hppfs_follow_link,
+        .permission     = hppfs_permission,
 };
 
 static struct inode *get_inode(struct super_block *sb, struct dentry *dentry)
@@ -712,7 +690,7 @@ static struct inode *get_inode(struct super_block *sb, struct dentry *dentry)
                 inode->i_fop = &hppfs_file_fops;
         }
 
-        HPPFS_I(inode)->proc_dentry = dentry;
+        HPPFS_I(inode)->proc_dentry = dget(dentry);
 
         inode->i_uid = proc_ino->i_uid;
         inode->i_gid = proc_ino->i_gid;
@@ -725,7 +703,7 @@ static struct inode *get_inode(struct super_block *sb, struct dentry *dentry)
         inode->i_size = proc_ino->i_size;
         inode->i_blocks = proc_ino->i_blocks;
 
-        return 0;
+        return inode;
 }
 
 static int hppfs_fill_super(struct super_block *sb, void *d, int silent)