From 6b9b3514aa188183e74049853be43380ad49314f Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:41 +0100 Subject: NFS: Add comment banners to some NFS functions Add comment banners to some NFS functions so that they can be modified by the NFS fscache patches for further information. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/nfs/file.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 0abf3f331f5..f5bc54dccec 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -409,6 +409,13 @@ static int nfs_write_end(struct file *file, struct address_space *mapping, return copied; } +/* + * Partially or wholly invalidate a page + * - Release the private state associated with a page if undergoing complete + * page invalidation + * - Called if either PG_private or PG_private_2 is set on the page + * - Caller holds page lock + */ static void nfs_invalidate_page(struct page *page, unsigned long offset) { dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset); @@ -419,6 +426,12 @@ static void nfs_invalidate_page(struct page *page, unsigned long offset) nfs_wb_page_cancel(page->mapping->host, page); } +/* + * Attempt to release the private state associated with a page + * - Called if either PG_private or PG_private_2 is set on the page + * - Caller holds page lock + * - Return true (may release page) or false (may not) + */ static int nfs_release_page(struct page *page, gfp_t gfp) { dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page); @@ -427,6 +440,14 @@ static int nfs_release_page(struct page *page, gfp_t gfp) return 0; } +/* + * Attempt to clear the private state associated with a page when an error + * occurs that requires the cached contents of an inode to be written back or + * destroyed + * - Called if either PG_private or PG_private_2 is set on the page + * - Caller holds page lock + * - Return 0 if successful, -error otherwise + */ static int nfs_launder_page(struct page *page) { struct inode *inode = page->mapping->host; @@ -451,6 +472,11 @@ const struct address_space_operations nfs_file_aops = { .launder_page = nfs_launder_page, }; +/* + * Notification that a PTE pointing to an NFS page is about to be made + * writable, implying that someone is about to modify the page through a + * shared-writable mapping + */ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) { struct page *page = vmf->page; -- cgit v1.2.3-70-g09d2