* [PATCH] Btrfs: avoid unnecessary scrub workers allocation
@ 2013-10-11 18:11 Wang Shilong
0 siblings, 0 replies; only message in thread
From: Wang Shilong @ 2013-10-11 18:11 UTC (permalink / raw
To: linux-btrfs; +Cc: wangsl.fnst
From: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
We only allocate scrub workers if we pass all the necessary
checks, for example, there are no operation in progress.
Besides, move mutex lock protection outside of scrub_workers_get()
/scrub_workers_put().
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
---
fs/btrfs/scrub.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index f21e2df..54e1830 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2784,7 +2784,6 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
{
int ret = 0;
- mutex_lock(&fs_info->scrub_lock);
if (fs_info->scrub_workers_refcnt == 0) {
if (is_dev_replace)
btrfs_init_workers(&fs_info->scrub_workers, "scrub", 1,
@@ -2814,21 +2813,17 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
}
++fs_info->scrub_workers_refcnt;
out:
- mutex_unlock(&fs_info->scrub_lock);
-
return ret;
}
static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
{
- mutex_lock(&fs_info->scrub_lock);
if (--fs_info->scrub_workers_refcnt == 0) {
btrfs_stop_workers(&fs_info->scrub_workers);
btrfs_stop_workers(&fs_info->scrub_wr_completion_workers);
btrfs_stop_workers(&fs_info->scrub_nocow_workers);
}
WARN_ON(fs_info->scrub_workers_refcnt < 0);
- mutex_unlock(&fs_info->scrub_lock);
}
int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
@@ -2889,23 +2884,18 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
return -EINVAL;
}
- ret = scrub_workers_get(fs_info, is_dev_replace);
- if (ret)
- return ret;
mutex_lock(&fs_info->fs_devices->device_list_mutex);
dev = btrfs_find_device(fs_info, devid, NULL, NULL);
if (!dev || (dev->missing && !is_dev_replace)) {
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
- scrub_workers_put(fs_info);
return -ENODEV;
}
- mutex_lock(&fs_info->scrub_lock);
+ mutex_lock(&fs_info->scrub_lock);
if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) {
mutex_unlock(&fs_info->scrub_lock);
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
- scrub_workers_put(fs_info);
return -EIO;
}
@@ -2916,10 +2906,17 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
btrfs_dev_replace_unlock(&fs_info->dev_replace);
mutex_unlock(&fs_info->scrub_lock);
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
- scrub_workers_put(fs_info);
return -EINPROGRESS;
}
btrfs_dev_replace_unlock(&fs_info->dev_replace);
+
+ ret = scrub_workers_get(fs_info, is_dev_replace);
+ if (ret) {
+ mutex_unlock(&fs_info->scrub_lock);
+ mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+ return ret;
+ }
+
sctx = scrub_setup_ctx(dev, is_dev_replace);
if (IS_ERR(sctx)) {
mutex_unlock(&fs_info->scrub_lock);
@@ -2955,10 +2952,10 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
mutex_lock(&fs_info->scrub_lock);
dev->scrub_device = NULL;
+ scrub_workers_put(fs_info);
mutex_unlock(&fs_info->scrub_lock);
scrub_free_ctx(sctx);
- scrub_workers_put(fs_info);
return ret;
}
--
1.7.11.7
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2013-10-11 18:11 [PATCH] Btrfs: avoid unnecessary scrub workers allocation Wang Shilong
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