Merge branch 'stable-3.2' into pandora-3.2

[pandora-kernel.git] / include / linux / fs.h

diff --git a/include/linux/fs.h b/include/linux/fs.h
index dd74385..12e19eb 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -486,6 +486,12 @@ struct iattr {
  */
 #include <linux/quota.h>
 
+/*
+ * Maximum number of layers of fs stack.  Needs to be limited to
+ * prevent kernel stack overflow
+ */
+#define FILESYSTEM_MAX_STACK_DEPTH 2
+
 /** 
  * enum positive_aop_returns - aop return codes with specific semantics
  *
@@ -645,7 +651,7 @@ 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 prio_tree_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 */
@@ -725,10 +731,35 @@ 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);
 }
 
 /*
@@ -1026,7 +1057,11 @@ struct file_handle {
        unsigned char f_handle[0];
 };
 
-#define get_file(x)    atomic_long_inc(&(x)->f_count)
+static inline struct file *get_file(struct file *f)
+{
+       atomic_long_inc(&f->f_count);
+       return f;
+}
 #define fput_atomic(x) atomic_long_add_unless(&(x)->f_count, -1, 1)
 #define file_count(x)  atomic_long_read(&(x)->f_count)
 
@@ -1410,6 +1445,9 @@ extern int send_sigurg(struct fown_struct *fown);
 #define UMOUNT_NOFOLLOW        0x00000008      /* Don't follow symlink on umount */
 #define UMOUNT_UNUSED  0x80000000      /* Flag guaranteed to be unused */
 
+/* sb->s_iflags */
+#define SB_I_MULTIROOT 0x00000008      /* Multiple roots to the dentry tree */
+
 extern struct list_head super_blocks;
 extern spinlock_t sb_lock;
 
@@ -1426,6 +1464,7 @@ struct super_block {
        const struct quotactl_ops       *s_qcop;
        const struct export_operations *s_export_op;
        unsigned long           s_flags;
+       unsigned long           s_iflags;       /* internal SB_I_* flags */
        unsigned long           s_magic;
        struct dentry           *s_root;
        struct rw_semaphore     s_umount;
@@ -1497,6 +1536,11 @@ struct super_block {
        int cleancache_poolid;
 
        struct shrinker s_shrink;       /* per-sb shrinker handle */
+
+       /*
+        * Indicates how deep in a filesystem stack this SB is
+        */
+       int s_stack_depth;
 };
 
 /* superblock cache pruning functions */
@@ -1962,6 +2006,11 @@ extern bool our_mnt(struct vfsmount *mnt);
 
 extern int current_umask(void);
 
+static inline struct inode *file_inode(struct file *f)
+{
+       return f->f_dentry->d_inode;
+}
+
 /* /sys/fs */
 extern struct kobject *fs_kobj;
 
@@ -2073,7 +2122,7 @@ extern long do_sys_open(int dfd, const char __user *filename, int flags,
                        int mode);
 extern struct file *filp_open(const char *, int, int);
 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
-                                  const char *, int);
+                                  const char *, int, umode_t);
 extern struct file * dentry_open(struct dentry *, struct vfsmount *, int,
                                 const struct cred *);
 extern int filp_close(struct file *, fl_owner_t id);
@@ -2604,7 +2653,7 @@ extern int buffer_migrate_page(struct address_space *,
 #define buffer_migrate_page NULL
 #endif
 
-extern int inode_change_ok(const struct inode *, struct iattr *);
+extern int setattr_prepare(struct dentry *, struct iattr *);
 extern int inode_newsize_ok(const struct inode *, loff_t offset);
 extern void setattr_copy(struct inode *inode, const struct iattr *attr);