diff options
| author | Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2011-04-20 10:09:16 +0000 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2011-05-23 13:24:43 -0400 |
| commit | 1f78160ce1b1b8e657e2248118c4d91f881763f0 (patch) | |
| tree | 98c5496a9ab3e77e4cd682c0487f4c0127198396 /fs/btrfs/disk-io.c | |
| parent | 46224705656633466ca7dc71d81b3c0abc76cae4 (diff) | |
Btrfs: using rcu lock in the reader side of devices list
fs_devices->devices is only updated on remove and add device paths, so we can
use rcu to protect it in the reader side
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/disk-io.c')
| -rw-r--r-- | fs/btrfs/disk-io.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 4e53a4fc467f..deba3d9c8853 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1410,8 +1410,8 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits) struct btrfs_device *device; struct backing_dev_info *bdi; - mutex_lock(&info->fs_devices->device_list_mutex); - list_for_each_entry(device, &info->fs_devices->devices, dev_list) { + rcu_read_lock(); + list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) { if (!device->bdev) continue; bdi = blk_get_backing_dev_info(device->bdev); @@ -1420,7 +1420,7 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits) break; } } - mutex_unlock(&info->fs_devices->device_list_mutex); + rcu_read_unlock(); return ret; } @@ -2332,9 +2332,9 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors) sb = &root->fs_info->super_for_commit; dev_item = &sb->dev_item; - mutex_lock(&root->fs_info->fs_devices->device_list_mutex); + rcu_read_lock(); head = &root->fs_info->fs_devices->devices; - list_for_each_entry(dev, head, dev_list) { + list_for_each_entry_rcu(dev, head, dev_list) { if (!dev->bdev) { total_errors++; continue; @@ -2367,7 +2367,7 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors) } total_errors = 0; - list_for_each_entry(dev, head, dev_list) { + list_for_each_entry_rcu(dev, head, dev_list) { if (!dev->bdev) continue; if (!dev->in_fs_metadata || !dev->writeable) @@ -2377,7 +2377,7 @@ int write_all_supers(struct btrfs_root *root, int max_mirrors) if (ret) total_errors++; } - mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); + rcu_read_unlock(); if (total_errors > max_errors) { printk(KERN_ERR "btrfs: %d errors while writing supers\n", total_errors); |