[PATCH 22/25] sysfs: sysfs_uptdate_file handle multiple superblocks

[Eric W. Biederman]

Teach sysfs_update_file how to handle multiple sysfs
superblocks.  Again we are just iterating over the superblocks
to so all of the filesystem modification notifications work
as expected.

Signed-off-by: Eric W. Biederman <ebiederm at xmission.com>
---
 fs/sysfs/file.c |   35 +++++++++++++++++++++--------------
 1 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index cff054f..1e6f9df 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -462,7 +462,8 @@ EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
 int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
 {
 	struct sysfs_dirent *victim_sd = NULL;
-	struct dentry *victim = NULL;
+	struct super_block *sb;
+	struct dentry *victim;
 	int rc;
 
 	rc = -ENOENT;
@@ -471,21 +472,27 @@ int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
 		goto out;
 
 	mutex_lock(&sysfs_rename_mutex);
-	victim = sysfs_get_dentry(sysfs_sb, victim_sd);
-	mutex_unlock(&sysfs_rename_mutex);
-	if (IS_ERR(victim)) {
-		rc = PTR_ERR(victim);
-		victim = NULL;
-		goto out;
+	sysfs_grab_supers();
+	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+		victim = sysfs_get_dentry(sb, victim_sd);
+		if (!victim)
+			continue;
+		if (IS_ERR(victim)) {
+			rc = PTR_ERR(victim);
+			victim = NULL;
+			goto out_unlock;
+		}
+		mutex_lock(&victim->d_inode->i_mutex);
+		victim->d_inode->i_mtime = CURRENT_TIME;
+		fsnotify_modify(victim);
+		mutex_unlock(&victim->d_inode->i_mutex);
+		rc = 0;
+		dput(victim);
 	}
-
-	mutex_lock(&victim->d_inode->i_mutex);
-	victim->d_inode->i_mtime = CURRENT_TIME;
-	fsnotify_modify(victim);
-	mutex_unlock(&victim->d_inode->i_mutex);
-	rc = 0;
+ out_unlock:
+	sysfs_release_supers();
+	mutex_unlock(&sysfs_rename_mutex);
  out:
-	dput(victim);
 	sysfs_put(victim_sd);
 	return rc;
 }
-- 
1.5.1.1.181.g2de0