Linux: Use positional r/w, not llseek
The Linux read/write file operations take a position. Use this
position to determine where we're reading or writing in a file,
rather than using the vfs_llseek() operator to set the file
position argument. This avoids a potential race condition, as
well as simplifying this code.
Change-Id: I82b4a109f9871fa2ce5b308bc32923b1bf910920
Reviewed-on: http://gerrit.openafs.org/1993
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Marc Dionne <marc.c.dionne@gmail.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>