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-rw-r--r--fs/btrfs/super.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 96eb9fe..0eb9a4d 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -54,6 +54,7 @@
#include "version.h"
#include "export.h"
#include "compression.h"
+#include "rcu-string.h"
#define CREATE_TRACE_POINTS
#include <trace/events/btrfs.h>
@@ -1482,12 +1483,44 @@ static void btrfs_fs_dirty_inode(struct inode *inode, int flags)
"error %d\n", btrfs_ino(inode), ret);
}
+static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
+ struct btrfs_fs_devices *cur_devices;
+ struct btrfs_device *dev, *first_dev = NULL;
+ struct list_head *head;
+ struct rcu_string *name;
+
+ mutex_lock(&fs_info->fs_devices->device_list_mutex);
+ cur_devices = fs_info->fs_devices;
+ while (cur_devices) {
+ head = &cur_devices->devices;
+ list_for_each_entry(dev, head, dev_list) {
+ if (!first_dev || dev->devid < first_dev->devid)
+ first_dev = dev;
+ }
+ cur_devices = cur_devices->seed;
+ }
+
+ if (first_dev) {
+ rcu_read_lock();
+ name = rcu_dereference(first_dev->name);
+ seq_escape(m, name->str, " \t\n\\");
+ rcu_read_unlock();
+ } else {
+ WARN_ON(1);
+ }
+ mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+ return 0;
+}
+
static const struct super_operations btrfs_super_ops = {
.drop_inode = btrfs_drop_inode,
.evict_inode = btrfs_evict_inode,
.put_super = btrfs_put_super,
.sync_fs = btrfs_sync_fs,
.show_options = btrfs_show_options,
+ .show_devname = btrfs_show_devname,
.write_inode = btrfs_write_inode,
.dirty_inode = btrfs_fs_dirty_inode,
.alloc_inode = btrfs_alloc_inode,
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