Fix corrupted l2_asize in arcstats

Commit e0b0ca9 accidentally corrupted the l2_asize displayed in
arcstats.  This was caused by changing the l2arc_buf_hdr.b_asize
member from an int to uint32_t type.  There are places in the
code where this field is cast to a uint64_t resulting in the
b_hits member being treated as part of b_asize.

To resolve the issue the type has been changed to a uint64_t,
and the b_hits member is placed after the enum to prevent the
size of the structure from increasing.

This is a good example of exactly why it's a bad idea to use
ambiguous types (int) in these structures.

Signed-off-by: DHE <git@dehacked.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1990

diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 2459c9326f0d28c16f75cd85145fad531b95e9e5..cbe0a6028cd3fa52f4215b60a268e08b9750bbe4 100644 (file)
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -743,8 +743,8 @@ struct l2arc_buf_hdr {
        /* compression applied to buffer data */
        enum zio_compress       b_compress;
        /* real alloc'd buffer size depending on b_compress applied */
-       uint32_t                b_asize;
        uint32_t                b_hits;
+       uint64_t                b_asize;
        /* temporary buffer holder for in-flight compressed data */
        void                    *b_tmp_cdata;
 };