CIFS: Fix async reading on reconnects

commit 038bc961c31b070269ecd07349a7ee2e839d4fec upstream.

If we get into read_into_pages() from cifs_readv_receive() and then
loose a network, we issue cifs_reconnect that moves all mids to
a private list and issue their callbacks. The callback of the async
read request sets a mid to retry, frees it and wakes up a process
that waits on the rdata completion.

After the connection is established we return from read_into_pages()
with a short read, use the mid that was freed before and try to read
the remaining data from the a newly created socket. Both actions are
not what we want to do. In reconnect cases (-EAGAIN) we should not
mask off the error with a short read but should return the error
code instead.

Acked-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 8b0c656f2ab26d79c10648fa38129bb38fc52265..97b03895ac8c9bc908202925d3faa6f2b5779f9f 100644 (file)
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2809,7 +2809,7 @@ cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
                total_read += result;
        }
 
-       return total_read > 0 ? total_read : result;
+       return total_read > 0 && result != -EAGAIN ? total_read : result;
 }
 
 static ssize_t
@@ -3232,7 +3232,7 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
                total_read += result;
        }
 
-       return total_read > 0 ? total_read : result;
+       return total_read > 0 && result != -EAGAIN ? total_read : result;
 }
 
 static int cifs_readpages(struct file *file, struct address_space *mapping,