From: Ilya Dryomov Date: Fri, 8 Aug 2014 08:43:39 +0000 (+0400) Subject: libceph: set last_piece in ceph_msg_data_pages_cursor_init() correctly X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=5f740d7e1531099b888410e6bab13f68da9b1a4d;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git libceph: set last_piece in ceph_msg_data_pages_cursor_init() correctly Determining ->last_piece based on the value of ->page_offset + length is incorrect because length here is the length of the entire message. ->last_piece set to false even if page array data item length is <= PAGE_SIZE, which results in invalid length passed to ceph_tcp_{send,recv}page() and causes various asserts to fire. # cat pages-cursor-init.sh #!/bin/bash rbd create --size 10 --image-format 2 foo FOO_DEV=$(rbd map foo) dd if=/dev/urandom of=$FOO_DEV bs=1M &>/dev/null rbd snap create foo@snap rbd snap protect foo@snap rbd clone foo@snap bar # rbd_resize calls librbd rbd_resize(), size is in bytes ./rbd_resize bar $(((4 << 20) + 512)) rbd resize --size 10 bar BAR_DEV=$(rbd map bar) # trigger a 512-byte copyup -- 512-byte page array data item dd if=/dev/urandom of=$BAR_DEV bs=1M count=1 seek=5 The problem exists only in ceph_msg_data_pages_cursor_init(), ceph_msg_data_pages_advance() does the right thing. The size_t cast is unnecessary. Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Ilya Dryomov Reviewed-by: Sage Weil Reviewed-by: Alex Elder --- diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index e51cad0db580..b2f571dd933d 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -901,7 +901,7 @@ static void ceph_msg_data_pages_cursor_init(struct ceph_msg_data_cursor *cursor, BUG_ON(page_count > (int)USHRT_MAX); cursor->page_count = (unsigned short)page_count; BUG_ON(length > SIZE_MAX - cursor->page_offset); - cursor->last_piece = (size_t)cursor->page_offset + length <= PAGE_SIZE; + cursor->last_piece = cursor->page_offset + cursor->resid <= PAGE_SIZE; } static struct page *