X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=include%2Flinux%2Ffs.h;h=12e19eb3934a6ac8268eccb0bfe75d39fe3063e6;hp=dd743859f04ef0bf4b926f44e09c45d4ff17e894;hb=fd15ae01c5b1c73f2c992afd219bd18856ae3e48;hpb=d63ff34838f434f99056ab6be25a5b55920283f0

diff --git a/include/linux/fs.h b/include/linux/fs.h
index dd743859f04e..12e19eb3934a 100644
--- 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);