@@ -957,6 +957,8 @@ int btrfs_reada_wait(void *handle)
struct reada_control *rc = handle;
while (atomic_read(&rc->elems)) {
+ if (!atomic_read(&works_cnt))
+ reada_start_machine(rc->root->fs_info);
wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0,
5 * HZ);
dump_devs(rc->root->fs_info,
@@ -975,6 +977,8 @@ int btrfs_reada_wait(void *handle)
struct reada_control *rc = handle;
while (atomic_read(&rc->elems)) {
+ if (!atomic_read(&works_cnt))
+ reada_start_machine(rc->root->fs_info);
wait_event(rc->wait, atomic_read(&rc->elems) == 0);
}
In some case, reada background works exit before all extents read, for example, if a device reachs workload limit(MAX_IN_FLIGHT), or total reads reachs max limit. In old code, every works queue 2x new works, so many works make above problem rarely happened. After we limit max works by patch titled: btrfs: reada: limit max works count The chance of above problem invreased. Fix: We can check running background works in btrfs_reada_wait(), and create one work if no works exist. Note: 1: It is patch for debug, discussed on following thread in maillist: Re: [PATCH 1/2] btrfs: reada: limit max works count I havn't reproduce problem in above mail until now, this patch is created by reviewing code. And I also havn't reproduced the problem before patch. I only comfirmed no-problem after this patch applied. 2: It is based on patch named: btrfs: reada: limit max works count The above patch and some detail in this patch needs more improvement before applied. Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> --- fs/btrfs/reada.c | 4 ++++ 1 file changed, 4 insertions(+)