vserver 1.9.3

[linux-2.6.git] / fs / nfs / symlink.c

diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c
index fabadfb..35f1065 100644 (file)
--- a/fs/nfs/symlink.c
+++ b/fs/nfs/symlink.c
@@ -23,20 +23,30 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/smp_lock.h>
+#include <linux/namei.h>
 
 /* Symlink caching in the page cache is even more simplistic
  * and straight-forward than readdir caching.
+ *
+ * At the beginning of the page we store pointer to struct page in question,
+ * simplifying nfs_put_link() (if inode got invalidated we can't find the page
+ * to be freed via pagecache lookup).
+ * The NUL-terminated string follows immediately thereafter.
  */
+
+struct nfs_symlink {
+       struct page *page;
+       char body[0];
+};
+
 static int nfs_symlink_filler(struct inode *inode, struct page *page)
 {
+       const unsigned int pgbase = offsetof(struct nfs_symlink, body);
+       const unsigned int pglen = PAGE_SIZE - pgbase;
        int error;
 
-       /* We place the length at the beginning of the page,
-        * in host byte order, followed by the string.  The
-        * XDR response verification will NULL terminate it.
-        */
        lock_kernel();
-       error = NFS_PROTO(inode)->readlink(inode, page);
+       error = NFS_PROTO(inode)->readlink(inode, page, pgbase, pglen);
        unlock_kernel();
        if (error < 0)
                goto error;
@@ -50,61 +60,58 @@ error:
        return -EIO;
 }
 
-static char *nfs_getlink(struct inode *inode, struct page **ppage)
+static int nfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
+       struct inode *inode = dentry->d_inode;
        struct page *page;
-       u32 *p;
-
-       page = ERR_PTR(nfs_revalidate_inode(NFS_SERVER(inode), inode));
-       if (page)
+       struct nfs_symlink *p;
+       void *err = ERR_PTR(nfs_revalidate_inode(NFS_SERVER(inode), inode));
+       if (err)
                goto read_failed;
        page = read_cache_page(&inode->i_data, 0,
                                (filler_t *)nfs_symlink_filler, inode);
-       if (IS_ERR(page))
+       if (IS_ERR(page)) {
+               err = page;
                goto read_failed;
-       if (!PageUptodate(page))
+       }
+       if (!PageUptodate(page)) {
+               err = ERR_PTR(-EIO);
                goto getlink_read_error;
-       *ppage = page;
+       }
        p = kmap(page);
-       return (char*)(p+1);
+       p->page = page;
+       nd_set_link(nd, p->body);
+       return 0;
 
 getlink_read_error:
        page_cache_release(page);
-       page = ERR_PTR(-EIO);
 read_failed:
-       return (char*)page;
+       nd_set_link(nd, err);
+       return 0;
 }
 
-static int nfs_readlink(struct dentry *dentry, char __user *buffer, int buflen)
+static void nfs_put_link(struct dentry *dentry, struct nameidata *nd)
 {
-       struct inode *inode = dentry->d_inode;
-       struct page *page = NULL;
-       int res = vfs_readlink(dentry,buffer,buflen,nfs_getlink(inode,&page));
-       if (page) {
-               kunmap(page);
-               page_cache_release(page);
-       }
-       return res;
-}
+       char *s = nd_get_link(nd);
+       if (!IS_ERR(s)) {
+               struct nfs_symlink *p;
+               struct page *page;
+
+               p = container_of(s, struct nfs_symlink, body[0]);
+               page = p->page;
 
-static int nfs_follow_link(struct dentry *dentry, struct nameidata *nd)
-{
-       struct inode *inode = dentry->d_inode;
-       struct page *page = NULL;
-       int res = vfs_follow_link(nd, nfs_getlink(inode,&page));
-       if (page) {
                kunmap(page);
                page_cache_release(page);
        }
-       return res;
 }
 
 /*
  * symlinks can't do much...
  */
 struct inode_operations nfs_symlink_inode_operations = {
-       .readlink       = nfs_readlink,
+       .readlink       = generic_readlink,
        .follow_link    = nfs_follow_link,
+       .put_link       = nfs_put_link,
        .getattr        = nfs_getattr,
        .setattr        = nfs_setattr,
 };