AFS: write support fixes

AFS write support fixes:

 (1) Support large files using the 64-bit file access operations if available
     on the server.

 (2) Use kmap_atomic() rather than kmap() in afs_prepare_page().

 (3) Don't do stuff in afs_writepage() that's done by the caller.

[akpm@linux-foundation.org: fix right shift count >= width of type]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 11 deletions

diff --git a/fs/afs/write.c b/fs/afs/write.c
index 83ff29262816..aa03d43984b3 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -122,7 +122,7 @@ static int afs_prepare_page(struct afs_vnode *vnode, struct page *page,
         if (offset == 0 && to == PAGE_SIZE)
                 return 0;
 
-        p = kmap(page);
+        p = kmap_atomic(page, KM_USER0);
 
         i_size = i_size_read(&vnode->vfs_inode);
         pos = (loff_t) page->index << PAGE_SHIFT;
@@ -133,7 +133,7 @@ static int afs_prepare_page(struct afs_vnode *vnode, struct page *page,
                         memset(p, 0, offset);
                 if (to < PAGE_SIZE)
                         memset(p + to, 0, PAGE_SIZE - to);
-                kunmap(page);
+                kunmap_atomic(p, KM_USER0);
                 return 0;
         }
 
@@ -152,7 +152,7 @@ static int afs_prepare_page(struct afs_vnode *vnode, struct page *page,
                         memset(p + eof, 0, PAGE_SIZE - eof);
         }
 
-        kunmap(p);
+        kunmap_atomic(p, KM_USER0);
 
         ret = 0;
         if (offset > 0 || eof > to) {
@@ -489,14 +489,6 @@ int afs_writepage(struct page *page, struct writeback_control *wbc)
 
         _enter("{%lx},", page->index);
 
-        if (wbc->sync_mode != WB_SYNC_NONE)
-                wait_on_page_writeback(page);
-
-        if (PageWriteback(page) || !PageDirty(page)) {
-                unlock_page(page);
-                return 0;
-        }
-
         wb = (struct afs_writeback *) page_private(page);
         ASSERT(wb != NULL);