fs: limit filesystem stacking depth

[sfrench/cifs-2.6.git] / include / linux / fs.h

diff --git a/include/linux/fs.h b/include/linux/fs.h
index ab4f1a10da20c7fd059c50235d32aa33322f64a9..4e41a4a331bbf96c4b59c05cd9a0c522efec92ca 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -192,8 +192,6 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 #define READ                   0
 #define WRITE                  RW_MASK
 #define READA                  RWA_MASK
-#define KERNEL_READ            (READ|REQ_KERNEL)
-#define KERNEL_WRITE           (WRITE|REQ_KERNEL)
 
 #define READ_SYNC              (READ | REQ_SYNC)
 #define WRITE_SYNC             (WRITE | REQ_SYNC | REQ_NOIDLE)
@@ -224,6 +222,13 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 #define ATTR_OPEN      (1 << 15) /* Truncating from open(O_TRUNC) */
 #define ATTR_TIMES_SET (1 << 16)
 
+/*
+ * Whiteout is represented by a char device.  The following constants define the
+ * mode and device number to use.
+ */
+#define WHITEOUT_MODE 0
+#define WHITEOUT_DEV 0
+
 /*
  * This is the Inode Attributes structure, used for notify_change().  It
  * uses the above definitions as flags, to know which values have changed.
@@ -256,6 +261,12 @@ 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
  *
@@ -1268,6 +1279,11 @@ struct super_block {
        struct list_lru         s_dentry_lru ____cacheline_aligned_in_smp;
        struct list_lru         s_inode_lru ____cacheline_aligned_in_smp;
        struct rcu_head         rcu;
+
+       /*
+        * Indicates how deep in a filesystem stack this SB is
+        */
+       int s_stack_depth;
 };
 
 extern struct timespec current_fs_time(struct super_block *sb);
@@ -1400,6 +1416,7 @@ extern int vfs_link(struct dentry *, struct inode *, struct dentry *, struct ino
 extern int vfs_rmdir(struct inode *, struct dentry *);
 extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
 extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
+extern int vfs_whiteout(struct inode *, struct dentry *);
 
 /*
  * VFS dentry helper functions.
@@ -1530,6 +1547,9 @@ struct inode_operations {
                           umode_t create_mode, int *opened);
        int (*tmpfile) (struct inode *, struct dentry *, umode_t);
        int (*set_acl)(struct inode *, struct posix_acl *, int);
+
+       /* WARNING: probably going away soon, do not use! */
+       int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
 } ____cacheline_aligned;
 
 ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
@@ -1627,6 +1647,9 @@ struct super_operations {
 #define IS_AUTOMOUNT(inode)    ((inode)->i_flags & S_AUTOMOUNT)
 #define IS_NOSEC(inode)                ((inode)->i_flags & S_NOSEC)
 
+#define IS_WHITEOUT(inode)     (S_ISCHR(inode->i_mode) && \
+                                (inode)->i_rdev == WHITEOUT_DEV)
+
 /*
  * Inode state bits.  Protected by inode->i_lock
  *
@@ -2042,6 +2065,7 @@ extern struct file *file_open_name(struct filename *, int, umode_t);
 extern struct file *filp_open(const char *, int, umode_t);
 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
                                   const char *, int);
+extern int vfs_open(const struct path *, struct file *, const struct cred *);
 extern struct file * dentry_open(const struct path *, int, const struct cred *);
 extern int filp_close(struct file *, fl_owner_t id);
 
@@ -2255,7 +2279,9 @@ extern sector_t bmap(struct inode *, sector_t);
 #endif
 extern int notify_change(struct dentry *, struct iattr *, struct inode **);
 extern int inode_permission(struct inode *, int);
+extern int __inode_permission(struct inode *, int);
 extern int generic_permission(struct inode *, int);
+extern int __check_sticky(struct inode *dir, struct inode *inode);
 
 static inline bool execute_ok(struct inode *inode)
 {
@@ -2454,6 +2480,9 @@ extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
                struct file *, loff_t *, size_t, unsigned int);
 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
                struct file *out, loff_t *, size_t len, unsigned int flags);
+extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
+               loff_t *opos, size_t len, unsigned int flags);
+
 
 extern void
 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
@@ -2739,6 +2768,14 @@ static inline int is_sxid(umode_t mode)
        return (mode & S_ISUID) || ((mode & S_ISGID) && (mode & S_IXGRP));
 }
 
+static inline int check_sticky(struct inode *dir, struct inode *inode)
+{
+       if (!(dir->i_mode & S_ISVTX))
+               return 0;
+
+       return __check_sticky(dir, inode);
+}
+
 static inline void inode_has_no_xattr(struct inode *inode)
 {
        if (!is_sxid(inode->i_mode) && (inode->i_sb->s_flags & MS_NOSEC))