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authorDavid Howells <dhowells@redhat.com>2009-04-03 16:42:41 +0100
committerDavid Howells <dhowells@redhat.com>2009-04-03 16:42:41 +0100
commit6b9b3514aa188183e74049853be43380ad49314f (patch)
tree738f333421c2f57447dc4534ae83a19708e487cf
parent9b3f26c9110dcea62716aca9b8c68ceb482227ef (diff)
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 <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
-rw-r--r--fs/nfs/file.c26
1 files changed, 26 insertions, 0 deletions
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;