Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux...

[cascardo/linux.git] / include / linux / fs.h

diff --git a/include/linux/fs.h b/include/linux/fs.h
index ac3a36e..c213b48 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -387,7 +387,7 @@ struct address_space {
        struct inode            *host;          /* owner: inode, block_device */
        struct radix_tree_root  page_tree;      /* radix tree of all pages */
        spinlock_t              tree_lock;      /* and lock protecting it */
-       unsigned int            i_mmap_writable;/* count VM_SHARED mappings */
+       atomic_t                i_mmap_writable;/* count VM_SHARED mappings */
        struct rb_root          i_mmap;         /* tree of private and shared mappings */
        struct list_head        i_mmap_nonlinear;/*list VM_NONLINEAR mappings */
        struct mutex            i_mmap_mutex;   /* protect tree, count, list */
@@ -470,10 +470,35 @@ static inline int mapping_mapped(struct address_space *mapping)
  * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
  * marks vma as VM_SHARED if it is shared, and the file was opened for
  * writing i.e. vma may be mprotected writable even if now readonly.
+ *
+ * If i_mmap_writable is negative, no new writable mappings are allowed. You
+ * can only deny writable mappings, if none exists right now.
  */
 static inline int mapping_writably_mapped(struct address_space *mapping)
 {
-       return mapping->i_mmap_writable != 0;
+       return atomic_read(&mapping->i_mmap_writable) > 0;
+}
+
+static inline int mapping_map_writable(struct address_space *mapping)
+{
+       return atomic_inc_unless_negative(&mapping->i_mmap_writable) ?
+               0 : -EPERM;
+}
+
+static inline void mapping_unmap_writable(struct address_space *mapping)
+{
+       atomic_dec(&mapping->i_mmap_writable);
+}
+
+static inline int mapping_deny_writable(struct address_space *mapping)
+{
+       return atomic_dec_unless_positive(&mapping->i_mmap_writable) ?
+               0 : -EBUSY;
+}
+
+static inline void mapping_allow_writable(struct address_space *mapping)
+{
+       atomic_inc(&mapping->i_mmap_writable);
 }
 
 /*
@@ -833,7 +858,7 @@ static inline struct file *get_file(struct file *f)
  *
  * Lockd stuffs a "host" pointer into this.
  */
-typedef struct files_struct *fl_owner_t;
+typedef void *fl_owner_t;
 
 struct file_lock_operations {
        void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
@@ -1250,6 +1275,7 @@ struct super_block {
 
        /* AIO completions deferred from interrupt context */
        struct workqueue_struct *s_dio_done_wq;
+       struct hlist_head s_pins;
 
        /*
         * Keep the lru lists last in the structure so they always sit on their
@@ -2336,6 +2362,7 @@ extern int do_pipe_flags(int *, int);
 
 extern int kernel_read(struct file *, loff_t, char *, unsigned long);
 extern ssize_t kernel_write(struct file *, const char *, size_t, loff_t);
+extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
 extern struct file * open_exec(const char *);
  
 /* fs/dcache.c -- generic fs support functions */
@@ -2689,7 +2716,7 @@ static const struct file_operations __fops = {                            \
        .read    = simple_attr_read,                                    \
        .write   = simple_attr_write,                                   \
        .llseek  = generic_file_llseek,                                 \
-};
+}
 
 static inline __printf(1, 2)
 void __simple_attr_check_format(const char *fmt, ...)