afs: Read of file returns EBADMSG

A read of a large file on an afs mount failed:

# cat junk.file > /dev/null
cat: junk.file: Bad message

Looking at the trace, call->offset wrapped since it is only an
unsigned short. In afs_extract_data:

        _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
...

        if (call->offset < count) {
                if (last) {
                        _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
                        return -EBADMSG;
                }

Which matches the trace:

[cat   ] ==> afs_extract_data({65132},{524},1,,65536)
[cat   ] <== afs_extract_data() = -EBADMSG [0 < 65536]

call->offset went from 65132 to 0. Fix this by making call->offset an
unsigned int.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index d2b0888..a306bb6 100644 (file)
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -109,7 +109,7 @@ struct afs_call {
        unsigned                reply_size;     /* current size of reply */
        unsigned                first_offset;   /* offset into mapping[first] */
        unsigned                last_to;        /* amount of mapping[last] */
-       unsigned short          offset;         /* offset into received data store */
+       unsigned                offset;         /* offset into received data store */
        unsigned char           unmarshall;     /* unmarshalling phase */
        bool                    incoming;       /* T if incoming call */
        bool                    send_pages;     /* T if data from mapping should be sent */