cifs: read pages from FS-Cache

Read pages from a FS-Cache data storage object into a CIFS inode.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/fs/cifs/fscache.c b/fs/cifs/fscache.c
index 3b1636704c85..9f3f5c4be161 100644
--- a/fs/cifs/fscache.c
+++ b/fs/cifs/fscache.c
@@ -140,6 +140,79 @@ int cifs_fscache_release_page(struct page *page, gfp_t gfp)
         return 1;
 }
 
+static void cifs_readpage_from_fscache_complete(struct page *page, void *ctx,
+                                                int error)
+{
+        cFYI(1, "CFS: readpage_from_fscache_complete (0x%p/%d)",
+                        page, error);
+        if (!error)
+                SetPageUptodate(page);
+        unlock_page(page);
+}
+
+/*
+ * Retrieve a page from FS-Cache
+ */
+int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
+{
+        int ret;
+
+        cFYI(1, "CIFS: readpage_from_fscache(fsc:%p, p:%p, i:0x%p",
+                        CIFS_I(inode)->fscache, page, inode);
+        ret = fscache_read_or_alloc_page(CIFS_I(inode)->fscache, page,
+                                         cifs_readpage_from_fscache_complete,
+                                         NULL,
+                                         GFP_KERNEL);
+        switch (ret) {
+
+        case 0: /* page found in fscache, read submitted */
+                cFYI(1, "CIFS: readpage_from_fscache: submitted");
+                return ret;
+        case -ENOBUFS:  /* page won't be cached */
+        case -ENODATA:  /* page not in cache */
+                cFYI(1, "CIFS: readpage_from_fscache %d", ret);
+                return 1;
+
+        default:
+                cERROR(1, "unknown error ret = %d", ret);
+        }
+        return ret;
+}
+
+/*
+ * Retrieve a set of pages from FS-Cache
+ */
+int __cifs_readpages_from_fscache(struct inode *inode,
+                                struct address_space *mapping,
+                                struct list_head *pages,
+                                unsigned *nr_pages)
+{
+        int ret;
+
+        cFYI(1, "CIFS: __cifs_readpages_from_fscache (0x%p/%u/0x%p)",
+                        CIFS_I(inode)->fscache, *nr_pages, inode);
+        ret = fscache_read_or_alloc_pages(CIFS_I(inode)->fscache, mapping,
+                                          pages, nr_pages,
+                                          cifs_readpage_from_fscache_complete,
+                                          NULL,
+                                          mapping_gfp_mask(mapping));
+        switch (ret) {
+        case 0: /* read submitted to the cache for all pages */
+                cFYI(1, "CIFS: readpages_from_fscache: submitted");
+                return ret;
+
+        case -ENOBUFS:  /* some pages are not cached and can't be */
+        case -ENODATA:  /* some pages are not cached */
+                cFYI(1, "CIFS: readpages_from_fscache: no page");
+                return 1;
+
+        default:
+                cFYI(1, "unknown error ret = %d", ret);
+        }
+
+        return ret;
+}
+
 void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
 {
         int ret;