Merge tag 'nfs-for-3.11-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

[cascardo/linux.git] / Documentation / filesystems / vfs.txt

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 1f0ba30..f93a882 100644 (file)
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -559,7 +559,6 @@ your filesystem. The following members are defined:
 struct address_space_operations {
        int (*writepage)(struct page *page, struct writeback_control *wbc);
        int (*readpage)(struct file *, struct page *);
-       int (*sync_page)(struct page *);
        int (*writepages)(struct address_space *, struct writeback_control *);
        int (*set_page_dirty)(struct page *page);
        int (*readpages)(struct file *filp, struct address_space *mapping,
@@ -581,6 +580,9 @@ struct address_space_operations {
        /* migrate the contents of a page to the specified target */
        int (*migratepage) (struct page *, struct page *);
        int (*launder_page) (struct page *);
+       int (*is_partially_uptodate) (struct page *, read_descriptor_t *,
+                                       unsigned long);
+       void (*is_dirty_writeback) (struct page *, bool *, bool *);
        int (*error_remove_page) (struct mapping *mapping, struct page *page);
        int (*swap_activate)(struct file *);
        int (*swap_deactivate)(struct file *);
@@ -612,13 +614,6 @@ struct address_space_operations {
        In this case, the page will be relocated, relocked and if
        that all succeeds, ->readpage will be called again.
 
-  sync_page: called by the VM to notify the backing store to perform all
-       queued I/O operations for a page. I/O operations for other pages
-       associated with this address_space object may also be performed.
-
-       This function is optional and is called only for pages with
-       PG_Writeback set while waiting for the writeback to complete.
-
   writepages: called by the VM to write out pages associated with the
        address_space object.  If wbc->sync_mode is WBC_SYNC_ALL, then
        the writeback_control will specify a range of pages that must be
@@ -747,6 +742,20 @@ struct address_space_operations {
        prevent redirtying the page, it is kept locked during the whole
        operation.
 
+  is_partially_uptodate: Called by the VM when reading a file through the
+       pagecache when the underlying blocksize != pagesize. If the required
+       block is up to date then the read can complete without needing the IO
+       to bring the whole page up to date.
+
+  is_dirty_writeback: Called by the VM when attempting to reclaim a page.
+       The VM uses dirty and writeback information to determine if it needs
+       to stall to allow flushers a chance to complete some IO. Ordinarily
+       it can use PageDirty and PageWriteback but some filesystems have
+       more complex state (unstable pages in NFS prevent reclaim) or
+       do not set those flags due to locking problems (jbd). This callback
+       allows a filesystem to indicate to the VM if a page should be
+       treated as dirty or writeback for the purposes of stalling.
+
   error_remove_page: normally set to generic_error_remove_page if truncation
        is ok for this address space. Used for memory failure handling.
        Setting this implies you deal with pages going away under you,