[PATCH] fix up new filp allocators

Some new uses of get_empty_filp() have crept in; switched
to alloc_file() to make sure that pieces of initialization
won't be missing.

We really need to kill get_empty_filp().

[AV] fixed dentry leak on failure exit in anon_inode_getfd()

Cc: Erez Zadok <ezk@cs.sunysb.edu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J Bruce Fields" <bfields@fieldses.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 23 insertions, 20 deletions

diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c
index 23321889d9b0..f42be069e085 100644
--- a/fs/anon_inodes.c
+++ b/fs/anon_inodes.c
@@ -81,13 +81,10 @@ int anon_inode_getfd(int *pfd, struct inode **pinode, struct file **pfile,
 
         if (IS_ERR(anon_inode_inode))
                 return -ENODEV;
-        file = get_empty_filp();
-        if (!file)
-                return -ENFILE;
 
         error = get_unused_fd();
         if (error < 0)
-                goto err_put_filp;
+                return error;
         fd = error;
 
         /*
@@ -114,14 +111,15 @@ int anon_inode_getfd(int *pfd, struct inode **pinode, struct file **pfile,
         dentry->d_flags &= ~DCACHE_UNHASHED;
         d_instantiate(dentry, anon_inode_inode);
 
-        file->f_path.mnt = mntget(anon_inode_mnt);
-        file->f_path.dentry = dentry;
+        error = -ENFILE;
+        file = alloc_file(anon_inode_mnt, dentry,
+                          FMODE_READ | FMODE_WRITE, fops);
+        if (!file)
+                goto err_dput;
         file->f_mapping = anon_inode_inode->i_mapping;
 
         file->f_pos = 0;
         file->f_flags = O_RDWR;
-        file->f_op = fops;
-        file->f_mode = FMODE_READ | FMODE_WRITE;
         file->f_version = 0;
         file->private_data = priv;
 
@@ -132,10 +130,10 @@ int anon_inode_getfd(int *pfd, struct inode **pinode, struct file **pfile,
         *pfile = file;
         return 0;
 
+err_dput:
+        dput(dentry);
 err_put_unused_fd:
         put_unused_fd(fd);
-err_put_filp:
-        put_filp(file);
         return error;
 }
 EXPORT_SYMBOL_GPL(anon_inode_getfd);
diff --git a/fs/file_table.c b/fs/file_table.c
index 6d27befe2d48..986ff4ed0a7c 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -83,6 +83,12 @@ int proc_nr_files(ctl_table *table, int write, struct file *filp,
 /* Find an unused file structure and return a pointer to it.
  * Returns NULL, if there are no more free file structures or
  * we run out of memory.
+ *
+ * Be very careful using this.  You are responsible for
+ * getting write access to any mount that you might assign
+ * to this filp, if it is opened for write.  If this is not
+ * done, you will imbalance int the mount's writer count
+ * and a warning at __fput() time.
  */
 struct file *get_empty_filp(void)
 {
diff --git a/fs/pipe.c b/fs/pipe.c
index 3c185b6527bc..8be381bbcb54 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -957,13 +957,10 @@ struct file *create_write_pipe(void)
         struct dentry *dentry;
         struct qstr name = { .name = "" };
 
-        f = get_empty_filp();
-        if (!f)
-                return ERR_PTR(-ENFILE);
         err = -ENFILE;
         inode = get_pipe_inode();
         if (!inode)
-                goto err_file;
+                goto err;
 
         err = -ENOMEM;
         dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name);
@@ -978,22 +975,24 @@ struct file *create_write_pipe(void)
          */
         dentry->d_flags &= ~DCACHE_UNHASHED;
         d_instantiate(dentry, inode);
-        f->f_path.mnt = mntget(pipe_mnt);
-        f->f_path.dentry = dentry;
+
+        err = -ENFILE;
+        f = alloc_file(pipe_mnt, dentry, FMODE_WRITE, &write_pipe_fops);
+        if (!f)
+                goto err_dentry;
         f->f_mapping = inode->i_mapping;
 
         f->f_flags = O_WRONLY;
-        f->f_op = &write_pipe_fops;
-        f->f_mode = FMODE_WRITE;
         f->f_version = 0;
 
         return f;
 
+ err_dentry:
+        dput(dentry);
  err_inode:
         free_pipe_info(inode);
         iput(inode);
- err_file:
-        put_filp(f);
+ err:
         return ERR_PTR(err);
 }