AFS: Don't put struct file on the stack

Don't put struct file on the stack as it takes up quite a lot of space
and violates lifetime rules for struct file.

Rather than calling afs_readpage() indirectly from the directory routines by
way of read_mapping_page(), split afs_readpage() to have afs_page_filler()
that's given a key instead of a file and call read_cache_page(), specifying the
new function directly.  Use it in afs_readpages() as well.

Also make use of this in afs_mntpt_check_symlink() too for the same reason.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index adc1cb7..b42d5cc 100644 (file)
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -189,13 +189,9 @@ static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
                                     struct key *key)
 {
        struct page *page;
-       struct file file = {
-               .private_data = key,
-       };
-
        _enter("{%lu},%lu", dir->i_ino, index);
 
-       page = read_mapping_page(dir->i_mapping, index, &file);
+       page = read_cache_page(dir->i_mapping, index, afs_page_filler, key);
        if (!IS_ERR(page)) {
                kmap(page);
                if (!PageChecked(page))

diff --git a/fs/afs/file.c b/fs/afs/file.c
index 0df9bc2..14d89fa 100644 (file)
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -121,34 +121,19 @@ static void afs_file_readpage_read_complete(struct page *page,
 #endif
 
 /*
- * AFS read page from file, directory or symlink
+ * read page from file, directory or symlink, given a key to use
  */
-static int afs_readpage(struct file *file, struct page *page)
+int afs_page_filler(void *data, struct page *page)
 {
-       struct afs_vnode *vnode;
-       struct inode *inode;
-       struct key *key;
+       struct inode *inode = page->mapping->host;
+       struct afs_vnode *vnode = AFS_FS_I(inode);
+       struct key *key = data;
        size_t len;
        off_t offset;
        int ret;
 
-       inode = page->mapping->host;
-
-       if (file) {
-               key = file->private_data;
-               ASSERT(key != NULL);
-       } else {
-               key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
-               if (IS_ERR(key)) {
-                       ret = PTR_ERR(key);
-                       goto error_nokey;
-               }
-       }
-
        _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
 
-       vnode = AFS_FS_I(inode);
-
        BUG_ON(!PageLocked(page));
 
        ret = -ESTALE;
@@ -214,31 +199,56 @@ static int afs_readpage(struct file *file, struct page *page)
                unlock_page(page);
        }
 
-       if (!file)
-               key_put(key);
        _leave(" = 0");
        return 0;
 
 error:
        SetPageError(page);
        unlock_page(page);
-       if (!file)
-               key_put(key);
-error_nokey:
        _leave(" = %d", ret);
        return ret;
 }
 
 /*
+ * read page from file, directory or symlink, given a file to nominate the key
+ * to be used
+ */
+static int afs_readpage(struct file *file, struct page *page)
+{
+       struct key *key;
+       int ret;
+
+       if (file) {
+               key = file->private_data;
+               ASSERT(key != NULL);
+               ret = afs_page_filler(key, page);
+       } else {
+               struct inode *inode = page->mapping->host;
+               key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
+               if (IS_ERR(key)) {
+                       ret = PTR_ERR(key);
+               } else {
+                       ret = afs_page_filler(key, page);
+                       key_put(key);
+               }
+       }
+       return ret;
+}
+
+/*
  * read a set of pages
  */
 static int afs_readpages(struct file *file, struct address_space *mapping,
                         struct list_head *pages, unsigned nr_pages)
 {
+       struct key *key = file->private_data;
        struct afs_vnode *vnode;
        int ret = 0;
 
-       _enter(",{%lu},,%d", mapping->host->i_ino, nr_pages);
+       _enter("{%d},{%lu},,%d",
+              key_serial(key), mapping->host->i_ino, nr_pages);
+
+       ASSERT(key != NULL);
 
        vnode = AFS_FS_I(mapping->host);
        if (vnode->flags & AFS_VNODE_DELETED) {
@@ -279,7 +289,7 @@ static int afs_readpages(struct file *file, struct address_space *mapping,
        }
 
        /* load the missing pages from the network */
-       ret = read_cache_pages(mapping, pages, (void *) afs_readpage, file);
+       ret = read_cache_pages(mapping, pages, afs_page_filler, key);
 
        _leave(" = %d [netting]", ret);
        return ret;

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index a10f258..807f284 100644 (file)
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -494,6 +494,7 @@ extern const struct file_operations afs_file_operations;
 
 extern int afs_open(struct inode *, struct file *);
 extern int afs_release(struct inode *, struct file *);
+extern int afs_page_filler(void *, struct page *);
 
 /*
  * flock.c

diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c
index b3feddc..a9e2303 100644 (file)
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -49,9 +49,6 @@ static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
  */
 int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
 {
-       struct file file = {
-               .private_data = key,
-       };
        struct page *page;
        size_t size;
        char *buf;
@@ -61,7 +58,8 @@ int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
               vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
 
        /* read the contents of the symlink into the pagecache */
-       page = read_mapping_page(AFS_VNODE_TO_I(vnode)->i_mapping, 0, &file);
+       page = read_cache_page(AFS_VNODE_TO_I(vnode)->i_mapping, 0,
+                              afs_page_filler, key);
        if (IS_ERR(page)) {
                ret = PTR_ERR(page);
                goto out;