Commit 146a1192 authored Mar 16, 2017 by David Howells

afs: Fix the maths in afs_fs_store_data()



afs_fs_store_data() works out of the size of the write it's going to make,
but it uses 32-bit unsigned subtraction in one place that gets
automatically cast to loff_t.

However, if to < offset, then the number goes negative, but as the result
isn't signed, this doesn't get sign-extended to 64-bits when placed in a
loff_t.

Fix by casting the operands to loff_t.

Signed-off-by: David Howells <dhowells@redhat.com>

parent 2f5705a5

fs/afs/fsclient.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1236,7 +1236,7 @@ int afs_fs_store_data(struct afs_server server, struct afs_writeback wb,
		_enter(",%x,{%x:%u},,",
		key_serial(wb->key), vnode->fid.vid, vnode->fid.vnode);

		size = to - offset;
		size = (loff_t)to - (loff_t)offset;
		if (first != last)
		size += (loff_t)(last - first) << PAGE_SHIFT;
		pos = (loff_t)first << PAGE_SHIFT;

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