From 7df05a4266fe8549cedb9a2d71bb8bff6ab11112 Mon Sep 17 00:00:00 2001 From: Richard Yao Date: Wed, 10 Oct 2012 23:57:45 -0400 Subject: [PATCH] Fix zfs_write_limit_max integer size mismatch on 32-bit systems Commit c409e4647f221ab724a0bd10c480ac95447203c3 introduced a number of module parameters. This required several types to be changed to accomidate the required module parameters Linux macros. Unfortunately, arc.c contained its own extern definition of the zfs_write_limit_max variable and its type was not updated to be consistent with its dsl_pool.c counterpart. If the variable had been properly marked extern in a common header, then gcc would have generated a warning and this would not have slipped through. The result of this was that the ARC unconditionally expected zfs_write_limit_max to be 64-bit. Unfortunately, the largest size integer module parameter that Linux supports is unsigned long, which varies in size depending on the host system's native word size. The effect was that on 32-bit systems, ARC incorrectly performed 64-bit operations on a 32-bit value by reading the neighboring 32 bits as the upper 32 bits of the 64-bit value. We correct that by changing the extern declaration to use the unsigned long type and move these extern definitions in to the common arc.h header. This should make ARC correctly treat zfs_write_limit_max as a 32-bit value on 32-bit systems. Reported-by: Jorgen Lundman Signed-off-by: Richard Yao Signed-off-by: Brian Behlendorf Closes #749 --- include/sys/arc.h | 5 +++++ module/zfs/arc.c | 4 ---- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/include/sys/arc.h b/include/sys/arc.h index dd9b128bc..443597df0 100644 --- a/include/sys/arc.h +++ b/include/sys/arc.h @@ -150,6 +150,11 @@ void l2arc_fini(void); void l2arc_start(void); void l2arc_stop(void); +/* Global tunings */ +extern int zfs_write_limit_shift; +extern unsigned long zfs_write_limit_max; +extern kmutex_t zfs_write_limit_lock; + #ifdef __cplusplus } #endif diff --git a/module/zfs/arc.c b/module/zfs/arc.c index 55f1909c5..829b4d9c3 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -147,10 +147,6 @@ static kmutex_t arc_reclaim_thr_lock; static kcondvar_t arc_reclaim_thr_cv; /* used to signal reclaim thr */ static uint8_t arc_thread_exit; -extern int zfs_write_limit_shift; -extern uint64_t zfs_write_limit_max; -extern kmutex_t zfs_write_limit_lock; - /* number of bytes to prune from caches when at arc_meta_limit is reached */ uint_t arc_meta_prune = 1048576; -- 2.40.0