fs: limit filesystem stacking depth

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

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2ae90d3..a509bee 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -92,6 +92,10 @@ struct inodes_stat_t {
 /* File is opened using open(.., 3, ..) and is writeable only for ioctls
    (specialy hack for floppy.c) */
 #define FMODE_WRITE_IOCTL      ((__force fmode_t)0x100)
+/* 32bit hashes as llseek() offset (for directories) */
+#define FMODE_32BITHASH         ((__force fmode_t)0x200)
+/* 64bit hashes as llseek() offset (for directories) */
+#define FMODE_64BITHASH         ((__force fmode_t)0x400)
 
 /*
  * Don't update ctime and mtime.
@@ -482,6 +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
  *
@@ -525,6 +535,7 @@ enum positive_aop_returns {
 struct page;
 struct address_space;
 struct writeback_control;
+enum migrate_mode;
 
 struct iov_iter {
        const struct iovec *iov;
@@ -614,7 +625,7 @@ struct address_space_operations {
         * is false, it must not block.
         */
        int (*migratepage) (struct address_space *,
-                       struct page *, struct page *, bool);
+                       struct page *, struct page *, enum migrate_mode);
        int (*launder_page) (struct page *);
        int (*is_partially_uptodate) (struct page *, read_descriptor_t *,
                                        unsigned long);
@@ -906,9 +917,11 @@ static inline loff_t i_size_read(const struct inode *inode)
 static inline void i_size_write(struct inode *inode, loff_t i_size)
 {
 #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+       preempt_disable();
        write_seqcount_begin(&inode->i_size_seqcount);
        inode->i_size = i_size;
        write_seqcount_end(&inode->i_size_seqcount);
+       preempt_enable();
 #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
        preempt_disable();
        inode->i_size = i_size;
@@ -1490,6 +1503,11 @@ 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 */
@@ -2066,7 +2084,7 @@ 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);
@@ -2102,6 +2120,7 @@ extern void bd_forget(struct inode *inode);
 extern void bdput(struct block_device *);
 extern void invalidate_bdev(struct block_device *);
 extern int sync_blockdev(struct block_device *bdev);
+extern void kill_bdev(struct block_device *);
 extern struct super_block *freeze_bdev(struct block_device *);
 extern void emergency_thaw_all(void);
 extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
@@ -2109,6 +2128,7 @@ extern int fsync_bdev(struct block_device *);
 #else
 static inline void bd_forget(struct inode *inode) {}
 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
+static inline void kill_bdev(struct block_device *bdev) {}
 static inline void invalidate_bdev(struct block_device *bdev) {}
 
 static inline struct super_block *freeze_bdev(struct block_device *sb)
@@ -2589,7 +2609,8 @@ extern int generic_check_addressable(unsigned, u64);
 
 #ifdef CONFIG_MIGRATION
 extern int buffer_migrate_page(struct address_space *,
-                               struct page *, struct page *, bool);
+                               struct page *, struct page *,
+                               enum migrate_mode);
 #else
 #define buffer_migrate_page NULL
 #endif