kernel-doc: detect/prevent duplicate doc section names

[linux-2.6-omap-h63xx.git] / fs / file_table.c

diff --git a/fs/file_table.c b/fs/file_table.c
index 664e3f2309b89811b028603da0f17a6e266ee9fd..7a0a9b8722513faae34fc0f145c06f241f2630f7 100644 (file)
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -42,6 +42,7 @@ static inline void file_free_rcu(struct rcu_head *head)
 static inline void file_free(struct file *f)
 {
        percpu_counter_dec(&nr_files);
+       file_check_state(f);
        call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
 }
 
@@ -83,6 +84,12 @@ 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)
 {
@@ -193,11 +200,23 @@ int init_file(struct file *file, struct vfsmount *mnt, struct dentry *dentry,
        file->f_mapping = dentry->d_inode->i_mapping;
        file->f_mode = mode;
        file->f_op = fop;
+
+       /*
+        * These mounts don't really matter in practice
+        * for r/o bind mounts.  They aren't userspace-
+        * visible.  We do this for consistency, and so
+        * that we can do debugging checks at __fput()
+        */
+       if ((mode & FMODE_WRITE) && !special_file(dentry->d_inode->i_mode)) {
+               file_take_write(file);
+               error = mnt_want_write(mnt);
+               WARN_ON(error);
+       }
        return error;
 }
 EXPORT_SYMBOL(init_file);
 
-void fastcall fput(struct file *file)
+void fput(struct file *file)
 {
        if (atomic_dec_and_test(&file->f_count))
                __fput(file);
@@ -205,10 +224,35 @@ void fastcall fput(struct file *file)
 
 EXPORT_SYMBOL(fput);
 
+/**
+ * drop_file_write_access - give up ability to write to a file
+ * @file: the file to which we will stop writing
+ *
+ * This is a central place which will give up the ability
+ * to write to @file, along with access to write through
+ * its vfsmount.
+ */
+void drop_file_write_access(struct file *file)
+{
+       struct vfsmount *mnt = file->f_path.mnt;
+       struct dentry *dentry = file->f_path.dentry;
+       struct inode *inode = dentry->d_inode;
+
+       put_write_access(inode);
+
+       if (special_file(inode->i_mode))
+               return;
+       if (file_check_writeable(file) != 0)
+               return;
+       mnt_drop_write(mnt);
+       file_release_write(file);
+}
+EXPORT_SYMBOL_GPL(drop_file_write_access);
+
 /* __fput is called from task context when aio completion releases the last
  * last use of a struct file *.  Do not use otherwise.
  */
-void fastcall __fput(struct file *file)
+void __fput(struct file *file)
 {
        struct dentry *dentry = file->f_path.dentry;
        struct vfsmount *mnt = file->f_path.mnt;
@@ -230,10 +274,10 @@ void fastcall __fput(struct file *file)
        if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL))
                cdev_put(inode->i_cdev);
        fops_put(file->f_op);
-       if (file->f_mode & FMODE_WRITE)
-               put_write_access(inode);
        put_pid(file->f_owner.pid);
        file_kill(file);
+       if (file->f_mode & FMODE_WRITE)
+               drop_file_write_access(file);
        file->f_path.dentry = NULL;
        file->f_path.mnt = NULL;
        file_free(file);
@@ -241,7 +285,7 @@ void fastcall __fput(struct file *file)
        mntput(mnt);
 }
 
-struct file fastcall *fget(unsigned int fd)
+struct file *fget(unsigned int fd)
 {
        struct file *file;
        struct files_struct *files = current->files;
@@ -269,7 +313,7 @@ EXPORT_SYMBOL(fget);
  * and a flag is returned to be passed to the corresponding fput_light().
  * There must not be a cloning between an fget_light/fput_light pair.
  */
-struct file fastcall *fget_light(unsigned int fd, int *fput_needed)
+struct file *fget_light(unsigned int fd, int *fput_needed)
 {
        struct file *file;
        struct files_struct *files = current->files;