From a298dbde92c68022a06ef51f2bb559b0975e4920 Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Mon, 15 Oct 2012 13:41:44 -0700 Subject: [PATCH] Condition variable usage, zp->r_{rd,wr}_cv The following incorrect usage of cv_broadcast() was caught by code inspection. The cv_broadcast() function must be called under the associated mutex to preventing racing with cv_wait(). Signed-off-by: Brian Behlendorf --- module/zfs/zfs_rlock.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/module/zfs/zfs_rlock.c b/module/zfs/zfs_rlock.c index 208de10f3..c278035b1 100644 --- a/module/zfs/zfs_rlock.c +++ b/module/zfs/zfs_rlock.c @@ -486,7 +486,7 @@ zfs_range_unlock_reader(znode_t *zp, rl_t *remove, list_t *free_list) */ if (remove->r_cnt == 1) { avl_remove(tree, remove); - mutex_exit(&zp->z_range_lock); + if (remove->r_write_wanted) cv_broadcast(&remove->r_wr_cv); @@ -530,7 +530,6 @@ zfs_range_unlock_reader(znode_t *zp, rl_t *remove, list_t *free_list) } } - mutex_exit(&zp->z_range_lock); kmem_free(remove, sizeof (rl_t)); } } @@ -554,7 +553,6 @@ zfs_range_unlock(rl_t *rl) if (rl->r_type == RL_WRITER) { /* writer locks can't be shared or split */ avl_remove(&zp->z_range_avl, rl); - mutex_exit(&zp->z_range_lock); if (rl->r_write_wanted) cv_broadcast(&rl->r_wr_cv); @@ -569,6 +567,7 @@ zfs_range_unlock(rl_t *rl) */ zfs_range_unlock_reader(zp, rl, &free_list); } + mutex_exit(&zp->z_range_lock); while ((free_rl = list_head(&free_list)) != NULL) { list_remove(&free_list, free_rl); @@ -599,11 +598,13 @@ zfs_range_reduce(rl_t *rl, uint64_t off, uint64_t len) mutex_enter(&zp->z_range_lock); rl->r_off = off; rl->r_len = len; - mutex_exit(&zp->z_range_lock); + if (rl->r_write_wanted) cv_broadcast(&rl->r_wr_cv); if (rl->r_read_wanted) cv_broadcast(&rl->r_rd_cv); + + mutex_exit(&zp->z_range_lock); } /*