[PATCH] madvise(MADV_REMOVE): remove pages from tmpfs shm backing store

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

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1b5f502a4b8fdb303f932079ac1f4498113d1374..115e72be25d0cd7b7a7436e4d82f389b7cbf7c8f 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -302,6 +302,37 @@ struct iattr {
  */
 #include <linux/quota.h>
 
+/** 
+ * enum positive_aop_returns - aop return codes with specific semantics
+ *
+ * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
+ *                         completed, that the page is still locked, and
+ *                         should be considered active.  The VM uses this hint
+ *                         to return the page to the active list -- it won't
+ *                         be a candidate for writeback again in the near
+ *                         future.  Other callers must be careful to unlock
+ *                         the page if they get this return.  Returned by
+ *                         writepage(); 
+ *
+ * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
+ *                     unlocked it and the page might have been truncated.
+ *                     The caller should back up to acquiring a new page and
+ *                     trying again.  The aop will be taking reasonable
+ *                     precautions not to livelock.  If the caller held a page
+ *                     reference, it should drop it before retrying.  Returned
+ *                     by readpage(), prepare_write(), and commit_write().
+ *
+ * address_space_operation functions return these large constants to indicate
+ * special semantics to the caller.  These are much larger than the bytes in a
+ * page to allow for functions that return the number of bytes operated on in a
+ * given page.
+ */
+
+enum positive_aop_returns {
+       AOP_WRITEPAGE_ACTIVATE  = 0x80000,
+       AOP_TRUNCATED_PAGE      = 0x80001,
+};
+
 /*
  * oh the beauties of C type declarations.
  */
@@ -874,6 +905,7 @@ static inline void unlock_super(struct super_block * sb)
 /*
  * VFS helper functions..
  */
+extern int vfs_permission(struct nameidata *, int);
 extern int vfs_create(struct inode *, struct dentry *, int, struct nameidata *);
 extern int vfs_mkdir(struct inode *, struct dentry *, int);
 extern int vfs_mknod(struct inode *, struct dentry *, int, dev_t);
@@ -888,6 +920,11 @@ extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct de
  */
 extern void dentry_unhash(struct dentry *dentry);
 
+/*
+ * VFS file helper functions.
+ */
+extern int file_permission(struct file *, int);
+
 /*
  * File types
  *
@@ -1013,6 +1050,7 @@ struct inode_operations {
        ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
        ssize_t (*listxattr) (struct dentry *, char *, size_t);
        int (*removexattr) (struct dentry *, const char *);
+       void (*truncate_range)(struct inode *, loff_t, loff_t);
 };
 
 struct seq_file;