afs: Make afs_init_request() get a key if not given a file

In a future patch, AFS directory caching will go through netfslib and this
will involve, at times, running on behalf of ->lookup(), which doesn't
provide us with a file from which we can get an authentication key.

If a file isn't provided, make afs_init_request() get a key from the
process's keyrings instead when setting up a read.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-21-dhowells@redhat.com
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/afs/file.c b/fs/afs/file.c
index f717168da4abb349136c183c2c2973cbdf571f09..a9d98d18407cf1c3bec5ce31859b2cbd832f5b45 100644 (file)
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -372,10 +372,26 @@ static int afs_symlink_read_folio(struct file *file, struct folio *folio)
 
 static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
 {
+       struct afs_vnode *vnode = AFS_FS_I(rreq->inode);
+
        if (file)
                rreq->netfs_priv = key_get(afs_file_key(file));
        rreq->rsize = 256 * 1024;
        rreq->wsize = 256 * 1024 * 1024;
+
+       switch (rreq->origin) {
+       case NETFS_READ_SINGLE:
+               if (!file) {
+                       struct key *key = afs_request_key(vnode->volume->cell);
+
+                       if (IS_ERR(key))
+                               return PTR_ERR(key);
+                       rreq->netfs_priv = key;
+               }
+               break;
+       default:
+               break;
+       }
        return 0;
 }