afs: Fix the maths in afs_fs_store_data()
authorDavid Howells <dhowells@redhat.com>
Thu, 16 Mar 2017 16:27:47 +0000 (16:27 +0000)
committerDavid Howells <dhowells@redhat.com>
Thu, 16 Mar 2017 16:27:47 +0000 (16:27 +0000)
commit146a1192783697810b63a1e41c4d59fc93387340
treef96b12c641b60681eeac2bfd612c8532793e6420
parent2f5705a5c805e7f761f2228820656bb9363a3d8c
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>
fs/afs/fsclient.c